UC Davis Recognizes latest research from WCEC: Laboratory Results of an Energy Efficient Dehumidifier for Indoor Farms

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WCEC completed its laboratory study on a new dehumidifier system for indoor farms. Read UC Davis’ take on this recent development:

https://www.ucdavis.edu/news/scientists-test-solutions-energy-efficient-grow-houses

Ventilation in Schools

Schools sought to participate in CEC-funded research on Proposition 39 upgrades
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The Western Cooling Efficiency Center (WCEC), an engineering research center at the University of California, Davis, has received a grant from the California Energy Commission (CEC) to demonstrate promising approaches to improve ventilation, indoor air quality, and energy efficiency in California classrooms.  Together with its research partners, the Energy Efficiency Center and Department of Public Health Sciences staff at UC Davis, and the Lawrence Berkeley National Laboratory, the WCEC team will conduct a 3-year study to:

  • Survey the energy efficiency and ventilation characteristics of recent HVAC retrofits in schools,
  • Field test the technical performance of advanced HVAC systems designed to deliver both improved ventilation and energy efficiency;
  • Estimate the potential benefits of widespread adoption of advanced HVAC systems, in terms of student health and performance, and environmental impact; and
  • Identify ways to address market barriers that currently impede broader market adoption of advanced HVAC technologies by California

Schools needed for Phase I

In the first phase, the research team will characterize the energy efficiency and ventilation characteristics of HVAC retrofits in California schools completed in recent years (2013-2016).  To do this, we will conduct in-field evaluations of 100 classrooms around the State for which HVAC retrofits have been completed through Proposition 39 since 2013.  WCEC engineers will visit each classroom to collect information on the HVAC system and ventilation design, measure the noise the HVAC system generates, and gather information about classroom features.  They will also install unobtrusive devices to record temperature, humidity and CO2 levels for one month.  Typically, site visits to collect data from classrooms are scheduled on days when students are not present, to minimize disruption.

 

Teachers who work in the classrooms enrolled in the study will be asked to complete a survey on their experience as an occupant of the room.  Questions relate to comfort when the HVAC system is heating and cooling, thermostat control, and air quality.  The online survey can be taken any time, at the teachers’ convenience.  It should take 15-20 minutes to complete, after which we will send teachers a $25 Target gift card.

 

As part of the study we are also gathering information on how decisions are made about HVAC equipment purchases and maintenance.  For that, we will ask relevant facilities staff from schools enrolled in the study to participate in an interview with one of our researchers.  Interviews will be scheduled at the staffs’ convenience, and interviewees will also be offered a $25 Target gift card.

 

Schools that participate in our study may request a summary of the observations our engineers noted while gathering data from 5-10 classrooms and HVAC systems.  The typical problems identified in schools often have simple fixes that can immediately improve air quality, energy efficiency and occupant experience.

 

The data collected from Phase I will allow the researchers to establish an understanding of the baseline conditions statewide by characterizing the HVAC efficiency, ventilation design, noise, occupant experience, and barriers to adoption of high efficiency systems.  These findings will inform our recommendations to synergistically improve ventilation and indoor environmental quality while providing HVAC and whole-building energy efficiency retrofits in California schools.

 

Who is eligible for the study?

Eligibility for the study is based on several criteria:

  • Schools must be located in SCE, PG&E or SDG&E territory
  • Schools must have installed HVAC system upgrades using Prop 39 funds within the last 3 years
  • HVAC replacements must serve single-zone classrooms
  • At least 5 eligible HVAC replacements must have been made at a single school

If you’re unsure whether your school meets this criteria we would be happy to discuss it with you.

How can schools enroll in the study?

Schools that meet the eligibility criteria outlined above can contact the research team by email at k12study@ucdavis.edu or meet with WCEC researcher Sarah Outcault in person at the Green Schools Summit.  She will circulate flyers at sessions related to Prop 39 and meet with attendees at the CEC booth during the Expo on Wednesday and Thursday.

 

WCEC Summer Newsletter

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In WCEC’s Summer Newsletter, we will look at:

  • » WCEC’s upcoming projects funded by the CEC’s EPIC program
  • » Research being done to help bridge some of the market barriers for energy efficient HVAC adoption with links to a video presentation and the project paper
  • » Recent WCEC Graduates
  • » Highlights from this year’s Affiliates Forum with presentation slides and poster session posters

Read the Newsletter

Undergraduate Research Fellowship for Energy Efficiency in Buildings


 

Undergraduate engineers are invited to apply to join an interdisciplinary research team to advance simulation of energy efficient building systems.

 

What the Fellowship Program can offer to students:

  • Gain practical experience with state of the art energy solutions
  • Develop numerical simulations of efficient heating and cooling strategies
  • Complete specialized coursework in energy efficiency
  • Develop expertise with simulation of building energy systems
  • Professional development and industrial experience

Applicants will have experience with and/or interest in:

  • Computer modeling of physical systems
  • Heat transfer and thermodynamics
  • Design and control of complex multi-mode systems
  • Energy efficiency and sustainability in the built environment
  • Matlab/Simulink, Python, C++, Excel as modeling tools

 

For more information

Download more information: DOE Undergraduate Research Fellowship Overview

Students, Apply now for an Interview:

SUBMIT APPLICATION AND CV THROUGH AGGIE JOB LINKS (DUE AUGUST 1st): http://goo.gl/Rx3wEQ
“ID #813755 – STDT4 – STUDENT ASSISTANT – WESTERN COOLING EFFICIENCY CENTER”

or contact Jonathan Woolley directly: jmwoolley@ucdavis.edu | (530) 204 7619

Automated Aerosol-Sealing of Building Envelopes

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Demonstration images of the Aerosol Envelope Sealing technology

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The goal of this project is to demonstrate a new technology for automating the air sealing of building envelopes. This technology is expected to reduce overall sealing costs while also achieving better air-tightness than conventional methods. One study by the National Institute of Standards and Technology (NIST) has shown that reducing infiltration to reasonable levels can result in a 30% heating and cooling energy savings. This result is based on the average energy savings predicted by models of multiple commercial building types in five major U.S. cities. Besides the energy impact, limiting uncontrolled infiltration by sealing building envelope leaks is critical to an effective ventilation strategy by facilitating control of the source of make-up air for occupied spaces.

 

Partners:
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Thermal Moisture Imaging (TMI) will be coordinating demonstrations and performing sealing work

 

Demonstration Host Site Locations:

  • Navy – Pennsylvania Installations
  • Parris Island, SC
  • Fort Bragg, NC
  • Quantico, VA
  • Travis AFB, CA

 

Status > May 2016:

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Custom Pressure Testing Apparatus at WCEC’s Laboratory in Davis, CA

WCEC has an approved demonstration plan and will begin demonstrations at the end of June. Six buildings have been identified at Quantico MCB and Ft. Bragg Army Base in North Carolina. In addition, laboratory testing is underway for measuring the impact of application humidity on seal durability. Seals formed in the laboratory will be subjected to temperature and pressure cyclic testing in order to quantify seal performance.

2016 WCEC Affiliates Forum

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A Gathering of HVAC Industry Stakeholders

Energy Efficiency Progress, Policy & Potential Development.

WCEC’s annual affiliates forum brings together HVAC industry stakeholders to discuss recent energy policy affecting the State of California, affiliate member news and developments, and research results published by WCEC. The forum’s goal is to create a diverse and relevant discussion on HVAC energy efficiency, pushing forward toward solutions and facilitating market impacts.

 

Presentations

Mark1WCEC Year in Review – Mark Modera, WCEC Director

Director Mark Modera highlights some of WCEC’s research for the previous year including:

  • New refrigerant testing
  • Next generation heat pump testing
  • Feasibility of evaporative cooling in drought-ridden California
  • ASHRAE standard for Evaporative Pre-Coolers
  • User-Oriented Modeling tools for Climate Appropriate Air Conditioners
  • Create training videos for 2016 Building Energy Efficiency Standards

(Download the PDF Presentation)


Nancy1California Energy Policy: Old and NewNancy Skinner, Energy Efficiency Center

Nancy takes us through previous energy efficiency policy in California and highlights current and new measures such as:

  • Prop 39: Energy Efficient Schools
  • SB 350: Transportation Electrification
  • AB 802: Benchmarking and energy use disclosure program
  • AB 2514: Energy Storage Mandate

(Download the PDF Presentation)

 

 

 

 

 

Affiliate Highlight SessionJim McClendon, Director of Engineering, Walmart  //  Amit Gupta, CEO, Aeroseal  //  Steve Slayzak, Engineer, Seeley

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Jim McClendon presents some insights on how Walmart handles deployment of energy efficient technologies/prototype testing over such a large portfolio of buildings in diverse geographical locations. (Download the PDF presentation)

Amit Gupta gives the history of Aeroseal and highlights its latest licensed technology: Automated sealing of building envelopes using aerosols. (Download the PDF presentation)

Steve Slayzak gives a brief overview of the purchase of Coolerado by Seeley and how their products compliment each other rather than compete.

 

Sarah1Market Barriers to Adoption of Efficient HVAC Retrofit Technologies – Sarah Outcault, Behavior Scientist, WCEC

Dr. Outcault presents information on why stakeholders choose to or not to buy, sell, adopt or promote energy efficient technologies.

(Download the PDF Presentation)

(Download the research report)

 

 

 

 

 

 

Theresa1WCEC Future ResearchVinod Naranayan, Associate Director, WCEC & Theresa Pistochini, Engineering Manager, WCEC

A brief look at some of the new research projects WCEC has started or will begin in the coming months:

  • Dispatchable pre-coolers for demand response
  • Aquachill remote technology
  • Sub Wet-bulb Evaporative chillers
  • De-humidification for Indoor Agriculture
  • Cost-constrained energy efficiency optimization for multifamily and commercial buildings
  • Ventilation solutions for California Schools
  • Shallow bore ground heat-exchangers for heat pumps
  • Energy efficient HVAC retrofits for residential buildings and more!

(Download the presentation)

 

Poster Session

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This year’s forum featured a flexible, 2-hour lunch and poster session within WCEC’s office. Here are the posters that were displayed during that session:

Does Evaporative Cooling Make Sense in Arid Climates?—Nasim Tajmand, Graduate Student Researcher, WCEC

Multi-Tenant Light Commercial Modeling Research –Nelson Dichter, Associate Engineer, WCEC

A New Termination Control Method for a Clothes Drying Process in a Clothes Dryer—Assistant Engineer, Caton Mande, WCEC

Performance Evaluation of a Thermal Storage Solution—Assistant Engineer, Jose Garcia, WCEC

High Performance Waste Heat Recuperators for Heat Recovery Cycles—Vinod Naranayan, Associate Director, WCEC

(Download the Posters)

Modeling Hybrid Air Conditioners—the BUILD DOE Team: Jonathan Woolley, Associate Engineer, WCEC // Yuanxian Chen, Yitian Liang, Nicholas Cabrena, Kyle Cheung

(Download the Poster)

 

 

WCEC’s Marco Pritoni Featured in Washington Post Article

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As the summer heats up, Americans are running their air conditioning more than ever. Author Chris Mooney of the Washington Post highlights the often overlooked, yet essential component to air conditioning: the thermostat. These devices are often confusing, and that confusion has lead to widespread misuse, increasing energy use and costs to the consumer.

While there are many previous reports that come to similar conclusions, the paper highlighted in the Washington Post asked respondents to upload photos of their thermostats. WCEC’s Marco Pritoni, co-author of this research paper is quoted in the Post with regards to these photos, “The responses to this survey paint a remarkable picture of a technology that is widely misunderstood by its users.”

Read the full Washington Post article here »

Read the Journal paper written by Marco Pritoni, Alan Meier, Cecilia Aragon, Daniel Perry, and Therese Peffer here »

Reshaping the Focus for HVAC Efficiency: WCEC’s 2014 Annual Report

WCEC latest Annual Report is now online. Download the PDF here. (NOTE: Filesize is 20MB)

WCEC’s Newsletter for October 2014

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This month’s newsletter includes WCEC’s first ever webinar open to the public! This webinar will explore the significant energy savings potential in laboratories.

Our featured content this month focuses on some of the latest behavioral research currently in progress at the Center including a look at how users interact with new, more advanced thermostats and their efficacy for energy savings & an examination of energy use behavior and interventions for two different ZNE communities: e-Sogo in Yokohama, Japan & West Village in Davis, California.

Also included is an invitation to join this year’s ETCC Emerging Technologies Summit happening October 20-22nd in San Francisco, CA. A new WCEC webinar is available to view online on enhancing DSM program portfolios.

Read the Newsletter

WCEC’ Welcomes Carel, Our New Affiliate

We are pleased to have Carel Industries join our diverse team of Affiliates and Partners. Carel Industries has an established history of over 35 years in production of humidifiers and controllers for HVAC. To learn more about Carel, please visit their website: http://www.carelusa.com/

 

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Carel Company Profile

CAREL USA was founded in January 1990 as DGH Systems. DGH Systems distributed Carel Humidification systems and Air Conditioning Controls in the United States from their manufacturing plant located in Lancaster, PA. In 2000, DGH Systems became part of CAREL INDUSTRIES S.r.l. and was renamed Carel USA, LLC. The company continues to produce Humidification systems and distribute Air Conditioning Controls and has become a leading player in the North American HVAC market.
In need of space to accommodate their continued growth, Carel USA bought 11 acres of land in Manheim, PA (20 minutes north of Lancaster, PA) in December 2004 and built a new 40,000 square foot facility. Shortly thereafter, the company entered the Refrigeration Controls market and began to promote Carel electronic controls in North America. In 2008, the internal quality system was audited and formally certified as per ISO9001:2000 Quality Standards.

While Carel USA continued to expand its manufacturing and engineering capabilities, it also expanded its reach to a broader range of HVAC and Refrigeration customers with a more widespread sales network. Regional representatives and factory employees are located throughout North America and work together with our customers to contribute to their success.

Today, Carel USA continues to lead the market with innovative products that are built on sound quality standards and that help customers achieve superior performances while limiting energy usage and reducing CO2 footprint.

CAREL INDUSTRIES S.r.l. has a history of over 35 years in the production of humidifiers and controllers for HVAC/R applications. The group is headquartered in the Italian industrial heartland of Brugine (Padova). As of December 2009, The CAREL Group employs more than 700 employees in 14 commercial subsidiaries and four manufacturing plants worldwide.

Revisiting Water-Use Efficiency for Evaporative Technologies

In terms of energy savings and, especially peak demand savings, there is little debate about the virtues of evaporative technologies in hot dry climates like California. By using water to cool or pre-cool supply air, evaporative technologies realize very significant energy savings. Depending on the product and application, evaporative technologies can save anywhere from 20-40% on cooling HVAC energy use and, in some real-world cases, savings of over 80% have been achieved. Using water to cool or pre-cool

It is perhaps a bit ironic though that the climate zones that benefit the most from evaporative cooling are also likely the climate zones that are most concerned with water conservation. Should these areas be concerned about the water-use for evaporative technologies? Is the energy savings worth it?

To answer these questions, one must take into account the water-use factors for a given area or climate zone. One factor that is often overlooked is the water consumption that is necessary in the creation of energy at the plant level. Coal, nuclear and hydro plants all consume water in the process of creating energy. This Source energy also has significant losses by the time it reaches the site where the energy will be consumed and thus, more energy is needed for the actual site demand and more water is consumed to create that energy. By saving energy at the site level through energy efficiency (such as evaporative cooling), water consumption is decreased at the power plant level and is conserved for other uses.

The analyses presented in this paper suggest that certain evaporative technologies that significantly reduce peak electricity demand and annual energy consumption need not consume any more water than conventional systems.

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Download the PDF

WCEC Newsletter April 2014

The Western Cooling Connection for April has just been released! Read the Newsletter now

WCEC Engineer Featured in The Davis Enterprise

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Each year, Cool Davis recognizes Davis residents who model how to incorporate sustainable practices into their work, civic and everyday lives. WCEC’s own Kristin Heinemeier was featured in today’s Davis Enterprise. Read the article here.

Honda Smart Home episode of Designing Spaces features WCEC Engineer

The Honda Smart Home at UC Davis

The Honda Smart Home at UC Davis

The “Think Green” special segment of Designing Spaces takes an in-depth look at the variety of technologies and innovations in the new, Net Zero home at UC Davis, the Honda Smart Home. The episode titled “A Zero Carbon Lifestyle Home and Transportation” aired on April 10th and highlighted all of the major innovations including the power management system, building materials, lighting and mechanical systems. WCEC engineer, Jonathan Woolley, was tapped by Designing Spaces to discuss his design for the mechanical systems (time marker: 11 minutes). Woolley briefly describes the integrated relationships between the heat pump, radiant system, geo-thermal system and waste heat recovery system that make the Honda Smart Home so efficient. Another innovation on display at the Honda Home yet not detailed in this episode was the use of aerosols to seal the building envelope. Using aerosols to seal the building envelope stops the infiltration of unwanted outside air and the exfiltration of conditioned air.

To watch this episode: http://www.designingspaces.tv/show_segment.php?id=1419

WCEC Co-Designed Honda Smart Home Featured in the New York Times

In the Business Day section on March 25th, the New York Times highlights just a few of the many innovations at the Honda Smart Home at UC Davis. The Honda Smart Home was designed in collaboration with the Western Cooling Efficiency Center, California Lighting Technology Center, Energy Efficiency Center and American Honda Motor Company. Read the Article

WCEC Publishes Journal Article on Evaporative Test Protocols

WCEC engineers Theresa Pistochini, Perry Young and Mark Modera published a paper in the Journal of Thermal Science and Engineering.

 

ABSTRACT:

Evaporative precoolers for air-cooled condensing units have been demonstrated to reduce electricity demand and save energy, particularly in arid climates. However, no objective, standardized test data for these products exists in the United States, making it difficult for end-users and utilities to evaluate expected performance prior to purchase and installation. This paper proposes a test protocol for evaporative precoolers installed on condensing units up to 70 kW, and then executes the protocol using three precooling products designed for residential split system air conditioners. Several methods of evaluating performance are compared and a method called the equivalent performance method is proposed. Without direct measurements, the method determines the equivalent temperature reduction of the condenser inlet air due to the precooler. While the performance of the products tested was poor, the products were selected based on convenience and are not expected to be representative of the market.

 

Read the Journal Article online

Western Cooling Challenge Featured in Indoor Comfort News

Western Cooling Challenge featured on the cover of Indoor Comfort News.

Western Cooling Challenge featured on the cover of Indoor Comfort News.

WCEC’s own Jonathan Woolley and the Western Cooling Challenge are featured on the cover of Indoor Comfort News. The article highlights some of ongoing field tests for Western Cooling Challenge Equipment including the Trane DC Voyager, Munters EPX5000, and Indirect Evaporative add-ons such as the Coolerado M50 and Seeley’s Climate Wizard.

Read the issue

Welcome three new Affiliates

E Source logo E Source logo Belimo logo

WCEC would like to formally welcome three new affiliates that have recently joined our Center. The first is E-Source. For more than 20 years, E Source’s Research and Advisory business model enables their customers to begin to immediately implement industry best practices in a variety of energy efficiency programs including utility customer satisfaction, program design, marketing, customer management and sustainability. For more information, please visit the E Source website.

Our second affiliate is actually a new research partner that represents over 120 years in the energy business, Tokyo Gas. Tokyo Gas is a leading energy company focused on natuaral gas businesses. The Tokyo Gas Group works to actively contribute to solutions that will promote an environmentally friendly society, maintain and enhance trust from our customers, shareholders and the international community. Currently, WCEC and Tokyo Gas are pursuing energy efficiency research in behavioral studies that will focus on identifying what behavioral triggers support energy efficiency decisions in a multi-family environment. For more information, please visit the Tokyo Gas website.

Our third new affiliate is our first affiliate with a heavy focus on controls and dampers. Belimo focuses solely on innovative technology in damper actuators and control valves. Since its inception in 1975, the major developments in HVAC actuator technology have come from Belimo. Belimo products help create comfort, safety, and efficiency in buildings. Our customers’ satisfaction and loyalty have made us a leader in HVAC throughout the world. Visit Belimo Projects to view an overview sampling of recent installation with energy savings. For more information, please visit the Belimo website.

WCEC Director Featured on Radio Talk Show

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WCEC Director Mark Modera spoke on the broad topic of innovation and efficiency and the roles of the efficiency center’s at UC Davis for tackling energy issues and climate change. An audio archive of the show can be downloaded here on the Peggy Smedley Show website.

About the Show
The Peggy Smedley Show, the voice of M2M and connected devices, is broadcast live each Tuesday from 12 p.m. – 1 p.m. CT on the Connected World Network, owned by Specialty Publishing Co., and a member of the World Syndicated Radio Network (wsRadio). The Peggy Smedley Show is a weekly radio show that helps listeners not only understand connected devices, but also how to make these devices a part of their everyday lives.

The show is fun, entertaining, and smart—yet educational and informative—and helps listeners understand the issues and challenges of implementing the newest technologies both in the workplace and at home. With more than 200 live shows to date, our host Peggy Smedley and her guests, help to bring knowledge, analysis, and a sense of humor to each weekly show. Our host strives to meet listener expectations with a wealth of unique segments and topics, keeping listeners up to date on the hottest products and services in the connected devices space.

About the Host
Peggy Smedley is an internationally known speaker and highly respected personality in the media world, educating businesses and consumers on the latest technological advances shaping everyday lives.

An outspoken advocate and supporter of connected devices and M2M technology, Peggy is the quick-witted host of The Peggy Smedley Show, the editorial director of Connected World magazine and its sister publication Constructech, as well as the president of Specialty Publishing Co.

Based in the Chicago area, Peggy is a renowned author and an award-winning editor, having earned numerous honors for editorial excellence. She has also been a guest on television business and news programs and has been a voice on many national commercially syndicated radio shows.

 

Smart Schools Symposium

A one-day event to improve the efficiency and performance of California’s K–12 facilities

September 5, 2013 | 8:30 a.m. – 4:30 p.m. | UC Davis Conference Center | 550 Alumni Lane, Davis (Map)

 

Registration

$25 ($35 after June 30)

Lunch included

Register for the Smart Schools Symposium

 

The UC Davis Energy Efficiency Center, Western Cooling Efficiency Center and the California Lighting Technology Center and in collaboration with Greenwise Joint Ventures would like to cordially invite you to a Forum that is focused on retrofitting and revitalizing K-12 educational facilities with energy efficient solutions and best practices.

 
With the passage of Proposition 39, schools may soon have new opportunities to make energy efficiency improvements. With entire buildings in need of attention, what should be addressed first?

This symposium will offer information and insights on creative financing for cost-effective retrofit solutions that can be completed without major renovations.

 

Who should attend?

This event is designed for a range of school leaders, including facilities managers, business officers, superintendents, principals, and school board members. WCEC affiliates and partners are welcome to attend the event, sponsor a booth, and/or present on specific HVAC topics that will be determined soon. Contact Paul Fortunato (pfortunato -at- ucdavis.edu) if you are interested in presenting at the Forum, or contact Liz Salmi from Greenwise to sponsor a booth.

Sign up to receive updates on symposium agenda and confirmed speakers.

 

Why register?

  • Staff from school districts throughout Northern California will share case studies of successful retrofits and lessons learned.
  • Energy efficiency experts will provide objective, evidence based recommendations for lighting and HVAC upgrades that improve both the quality and efficiency of school facilities.
  • Financial professionals will also be on hand to share their expertise and guidance.

Register now.

 

For more information:

Liz Salmi*Communications & EngagementGreenwise Joint Venture

liz @ greenwisejv.org

(916) 520-4581

*Contact Liz for sponsorship opportunities.

Paul Fortunato, Outreach Coordinator, Western Cooling Efficiency Center, UC Davis

pfortunato @ ucdavis.edu

(530) 752-0280

WCEC Director to Present at International Workshop in Washington, DC

Professor Mark Modera, Director of the Western Cooling Efficiency Center

Dr. Modera, Director of the Western Cooling Efficiency Center, on-site at a demonstration utilizing the automated process of sealing using aerosolized adhesives for building envelopes in Stockton, California.

Mark Modera, Director of the Western Cooling Efficiency Center, will be presenting his field experience findings on sealing large building duct leakage with an aerosol-based sealing process. This presentation will be given to a large international audience in Washington DC on April 18th-19th at the AIVC (Air Infiltration and Ventilation Centre) International Workshop for Building and Ductwork Airtightness. Modera joins 40 other HVAC luminaries that span 16 different countries to give presentations that explore the problems, solutions and best practices for dealing with the energy loss due to leaky buildings and ductwork.

Modera’s work in this field spans over 2 decades of research and the successful creation of an automated duct-leakage sealing system. This system, first commercialized for residential applications, utilizes aerosolized adhesives to seek out leaks–even those that go undetected by manual sealing–and seal them quickly, with real-time verification. His presentation focuses on a field study that shows the efficacy of this technology in larger commercial building applications by applying the aerosol technology to 11 different buildings and sealing these ducts by over 90%.

In residential applications, the main motivating factor for sealing ducts is to save energy. Larger commercial applications are interested in this potential as well, but the initial cost to test and implement such a system in larger buildings is quite significant if energy savings were the only impetus. It turns out that there are other important reasons for sealing ductwork in large buildings that include: 1) reducing inadequate zone air flow 2) getting a building to proper code specifications for flows or pressures 3) comfort and 4) reducing overall ventilation rates. Mitigating these factors can be much more financially beneficial to building owners than just pure energy concerns.

Download Dr. Modera’s research summary

 

About AIVC
Ventilation and air infiltration into buildings represent a substantial energy demand which can account for between 25% to over 50% of a building’s total space heating (or cooling) needs. Unnecessary or excessive air change can therefore have an important impact on global energy use. On the other hand insufficient ventilation may result in poor indoor air quality and consequential health problems.

Designing for optimum ventilation performance is hence a vital part of building design. This task is made especially difficult, however, by the complexities of airflow behaviour, climatic influences, occupancy patterns and pollutant emission characteristics.

In recognition of the significant impact of ventilation on energy use, combined with concerns over indoor air quality, the International Energy Agency (IEA) inaugurated the Air Infiltration and Ventilation Centre in 1979 (To be more precise, the AIVC is one of the annexes running under the ECBCS, Energy Conservation in Buildings and Community Systems, which is one of the Implementing Agreements of the IEA). The AIVC offers industry and research organisations technical support aimed at optimising ventilation technology. We offer a range of services and facilities, including comprehensive database on literature standards, and ventilation data.

We also produce a series of guides and technical notes.The Centre holds annual conferences and workshops.

The operating agent of the AIVC is INIVE eeig (www.inive.org)

The following countries participate in the AIVC.

Belgium, Czech Republic, Denmark, France, Germany, Greece, Italy, Japan, Netherlands, New Zealand, Norway, Portugal, Republic of Korea, Sweden, USA

WCEC In the News: Aerosol Envelope Sealing Research Published in Multiple Outlets

WCEC’s research on aerosol-based automated sealing of building envelopes is featured in these media outlets:

News 10

Video link


Stockton Recorder

Curtis Harrington inspecting nozzle spray for the aerosol based envelope sealing test.

It’s not quite ready for “This Old House,” but a University of California, Davis, professor says he’s found a new way to seal up homes without relying on caulking guns and the imperfect human eye.
A team of Davis folks and interested observers crowded into the garage of a Stockton home under construction by Habitat for Humanity on Tuesday to demonstrate the new technology.
A tank in the garage fed a nitrogen sealant solution into tubes snaking through the house. In each room, the tubes led to nozzles about 5 feet above ground. The nozzles released the liquid sealant just like misters shoot out water on a hot day… Read More»

UC Davis News

George Koertzen of Habitat for Humanity observing the aerosol-based automated building envelope sealing demonstration.

A new building-sealing technology developed by researchers at the University of California, Davis, will get a real-world test today at a Habitat for Humanity home in Stockton, Calif.

Developed by scientists at the UC Davis Western Cooling Efficiency Center, the green technology is designed to take the guesswork out of sealing building leaks, which account for roughly 30 percent of the energy used to heat and cool a building.

Previous testing has shown that the UC Davis aerosol sealing technology can reduce available leaks by 50 percent. With further improvements, the researchers think it has the potential to bring leakage down to nearly zero… Read More»


Sacramento Business Journal

WCEC Director Mark Modera discussing the aerosol-based automated building envelope sealing demonstration to a reporter from News 10.

A research effort at the University of California Davis is touting a potential breakthrough that might be of considerable interest to homebuilders looking for energy efficiency.
Using a compressed nitrogen system developed at the university’s Western Cooling Efficiency Center, a sealant is pushed through five nozzles and seeks out, then seals, areas where air is leaking from a structure.
The center announced the system’s development Tuesday in a press release, and officials said it’s capable of plugging as much as 50 percent of the leaks found in a home. Reducing such leaks could help new home builders meet a state mandate for new homes to use zero net energy by 2020 by reducing the amount of escaped heating and cooling air… Read More»
The UC Davis press release was also featured on these websites: The Mountain Democrat and Phys.org

Aerosol Envelope Sealing Update: Crafting a Better Adhesive

WCEC’s previous envelope sealing tests were successful at effectively sealing over 50% of the available leaks in 2 different homes. The only issue with using the previous sealant was that it retained its stickiness almost indefinitely. This made it much less likely to be used in a retrofit without larger, more involved preparation beforehand. To make this technology more attractive and convenient for contractors to use, WCEC is working with a liquid adhesive manufacturer to help craft a more suitable product. On February 14th, in Stockton California, WCEC tested the new adhesive in another rough-in home provided by Habitat for Humanity.    
 

How Effective Was this New Formula Adhesive?
Nelson Dichter, one of WCEC’s field engineers confirmed some positive findings, “During the sealing process, I often enter the house to move the injector,” Dichter said. “What I noticed most was that the new adhesive could be easily wiped off my hair and body. Yet in larger clumps where it sealed leaks, the sealant hardened nicely to create a strong seal. The previous sealant was more problematic when moving the injector nozzle because it always remained sticky, and was difficult to clean off of any surface, including me.” Dichter concluded, “This sealant shows great promise.”

“There was one drawback to the new sealant,” said WCEC’s engineer Curtis Harrington, “it took longer to form seals at leak points compared to the previous adhesive.” Harrington continued,“The new sealant definitely took longer to get the house sealed up and required much more of it to fully seal a house. For this test, since we did not have another cannister of the new sealant, we decided to finish up the house with the previous sealant.” Harrington concluded, “We are confident that this particular sealant will only require some minor adjustments to find that balance between tackiness and hardness, to get the best overall seal with the least amount of clean-up time.”

The Next Steps Towards Commercialization
To solve the issue of requiring more sealant to fully seal a house and to dramatically reduce the sealing time, WCEC has developed a new, multi-point injection system. This system uses pressurized nitrogen instead of an air compressor to push the sealant out of the 6 available injection nozzles. This also allows the system to not require as much electrical power since the largest power draw besides the blower door is the air compressor. WCEC will begin real world testing of this system next week in another house provided by Habitat For Humanity. A full write up including results from this promising new technology will be available in WCEC’s next quarterly newsletter.
 

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PIER Diagnostic Evaluator Project Meeting

FDD Meeting 1

WCEC co-hosted a meeting this month to review the results of a CEC/PIER- and NIST-funded research project carried out by Purdue University via a contract with New Buildings Institute. This well-attended gathering of over 30 stakeholders spanned much of the HVAC industry including energy consultants, HVAC Manufacturers, government regulators, Utilities and worker representation groups.

David Yuill, a doctoral student at Purdue and the primary researcher on the project, reported on the development and testing of a Fault Detection and Diagnostics (FDD) algorithm evaluator. This evaluator is based upon laboratory data from a range of different investigators, and it can apply an FDD algorithm and determine whether or not the resulting alarms reflect the conditions that were measured in the lab. This evaluator will allow standards such as Title 24 to accurately and fairly judge the appropriateness of FDD tools, and will allow utility program planners to pick the best tools for their installation and maintenance programs.

WCEC, and West Village at large, are focused on creating a central hub of energy efficiency for all interested stakeholders to share knowledge and collaborate. When asked about the overall meeting experience, meeting organizer Mark Cherniak said,

Everything went well from the logistics of parking and facilities to the meeting content itself. I’d recommend the center [WCEC] for meetings anytime.

PIER Diagnostic Evaluator Project with Herrick Laboratories, Purdue University. Dr. James Braun, Principal Investigator. Managed by New Buildings Institute. For more information contact: Mark Cherniack, markc -at- newbuildings.org
 

Residential Radiant Systems: A Potential Solution to Reduce Residential Peak Demand Energy Use

William AllenWilliam Allen, Ph.D., Associate Development Engineer and head of the WCEC Residential Radiant project 
 

Residential Radiant ceiling panel prototype. Designed by WCEC and tested in a Sacramento home
 
 


Residential Radiant chilled water storage tank to offset peak load demand. Designed by WCEC and tested in a Sacramento home  
 

Whether for environmental or monetary reasons, energy efficiency and reduced energy use concerns have permeated into the collective consciousness of most people. Today, most homes are outfitted with CFL light bulbs that use a fraction of the energy as yesterday’s incandescent lamps (many switching to an even lower energy-use LED lamp) and HVAC units with a SEER greater than 13 are much more commonplace. All of these energy efficient technologies are helping to reduce overall energy consumption, but most of these now ubiquitous products have only a marginal impact on peak load use.    
 

What is Peak Energy Demand?
Peak demand, or peak load use, is the 6 hour window typically between 2pm-8pm when the demand for cooling is highest. We leave the comfort of our offices, come home, turn on the lights and crank the thermostats in our homes to our desired temperature. This has a significant impact on our power grid and utility infrastructure that has to build and maintain inefficient, quick and dirty power stations just to meet this demand.

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How Radiant Cooling Works
Radiant cooling works by actively chilling large surfaces in a space (usually either the floor or the ceiling). This allows them to absorb heat from surrounding surfaces, including the human body. Cooling is most often provided by cold water circulating in copper or PEX pipes. This type of cooling usually makes a room feel more consistently cool than a forced air system that may have cold spots near a vent. In a room with cool surfaces, people will tend to feel comfortable at a slightly higher thermostat setting than with a forced air system, thus saving energy. Radiant systems also aren’t susceptible to duct losses typical in most residential forced-air systems.

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Peak-Load Shifting
A standard, forced-air system relies on the outdoor condenser to remove heat from the refrigerant. Unfortunately, at peak-demand hours, these systems are running at their least efficient because ambient outdoor-air temperatures are already so high, increasing power use on the system to remove the excess heat. A water-cooled condenser can help alleviate the inefficiencies of running a condenser during hot, peak hours reducing a typical HVAC’s system draw during peak by 30%-50%, but is nowhere near as substantial a peak-reduction as what can be obtained by radiant systems. With a chilled water storage tank, a radiant system can reduce peak-time demand energy use by 95%… using only a fraction of energy to move the water through the system and keep the sensors/thermostat on. Later on at night during off-peak hours, when the outdoor air temperature has dropped, the chilled water storage tank turns on its condenser to cool the water in the storage tank for the next day’s hot weather; dramatically reducing peak demand and increasing efficiency of condenser operation due to cooler ambient runtime temperatures.
 
 
WCEC’s own William Allen has been researching the use of radiant systems in residential applications for over 3 years now, looking into the economic and practical viability of this technology. His research implements 2 different radiant system designs in homes in Sacramento, including a chilled water storage tank for peak load shifting. The report also highlights the market challenges for new HVAC technology and proposes some solutions for these systems to gain a foothold in the greater HVAC marketplace. He is currently in the process of finalizing his findings for the CEC.
 

Q: What do you find most promising about radiant technology?
3 things:
1) The potential for energy savings is significant due to the elimination of duct losses typically found in standard forced air systems, and the fact that using water a heat transport medium saves energy due to low pump power rather than the relatively high power used by fans for blowing air.
2) A radiant system’s large active area cools or heats more evenly throughout a space, removing entirely the hot/cold spots typically found in forced air systems. This greatly increases occupant comfort levels.
3) The potential for load shifting through a chilled water storage system. This load shifting not only reduces peak demand load off the utilities, but it also increases efficiency gains due to the condenser running later at night, when ambient temperatures are much lower than during the peak demand hours. It can also allow the use of evaporative or hybrid cooling systems, which will also tend to run more efficiently during cooler night hours.  
 

Q: What was the main focus for this research project?
The main focus of the project is to investigate, design and implement a cost effective radiant system with peak load shifting for use in new build houses or as a retrofit. This effort required market research, including existing solutions, development of an integrated control system for heating/cooling and the development of a cost effective chilled water storage system. Traditionally, these types of storage systems are only cost effective for larger applications, so we set out to create something that could be economically viable on a smaller scale. 
 

Q: What challenges did you encounter?
The downturn in the housing market made it more difficult to find new-build test sites. Finding industrial partners for the storage elements and panels was also very difficult, again due to the market downturn, which led to manufacturers being reluctant to commit the R&D money to develop a product like this. This led to WCEC to design our own prototype panels which we predict would have an installed cost of less than $5/sqft, compared to the typical $12-$15 for existing systems. We have also worked with Uponor who are developing a panel designed for new build installation with a projected cost of less than $4/sqft.
 

Q: What are the next steps for radiant to become a more prevalent technology?
We need to do wider field demonstrations and work with utilities to add incentives for load shifting to bring down customer first costs, as well educating the public about the benefits of radiant systems.

 

Q: What should be the next technological challenge that WCEC should take on in order to further advance the implementation of radiant technology?
We need to work with a major player in the marketplace to develop a ‘plug and play’ control system, and turn-key radiant system solution. At the moment, radiant is treated as a custom install, and is therefore not part of the standard HVAC lexicon with builders, installers and contractors. Because of this, radiant systems are rarely recommended by builders because they simply do not know enough about radiant and don’t know many contractors willing to install these systems. This lack of awareness about these systems limits demand which keeps prices high and prevents cost reductions available due to economies of scale. If we can work together with builders and manufacturers to create more modular systems, radiant cooling could break out of the niche mold it has been in for 30+ years.

 


 

Demonstrations Program Update & Interview with David Grupp

David GruppDavid Grupp, Associate Engineer and head of the WCEC division of the SPEED demonstrations program 
 
A few HVAC case study demonstrations done by WCEC

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Click to download  
 

To view more case studies, please visit the State Partnership for Energy Efficient (SPEED) Demonstrations Website

One of the biggest barriers to the proliferation and adoption of energy efficient technologies is the perceived risk. Will these products actually save energy once they are installed in a real-world environment? Are they resilient enough to stand the test of time like their tried-and-true standard cooling solution cousins? What are the real-world return-on-investment rates for these products?    
 

To help solve these questions in a risk-adverse market, the CEC created PIER, the The Public Interest Energy Research Program as an R&D arm of the energy commission that works to find energy efficiency solutions by bringing together utilities, manufacturers, and world-class scientists at California’s universities and national laboratories. The implementation arm of PIER that puts these new, realized technologies into real-world demonstration testing is SPEED (The State Partnership for Energy Efficient Demonstrations). 
 

SPEED partners with university research facilities like the WCEC and the CLTC to evaluate new energy efficient technologies and then install, test and monitor these technologies at California Universities. Technologies such as Bi-level LED lighting, smart controls, Demand Control Kitchen Ventilation, Evaporative Cooling, Fault Detection and intelligent energy management systems are just a few of the well researched technologies that SPEED implements on California’s colleges. The HVAC-based energy efficient technologies arm of SPEED’s research is headed by WCEC’s own David Grupp.  
 

Q: What is the latest project for SPEED you are working on?
I am currently evaluating an intelligent energy management system by Vigilent. My initial goal is to build a set of standardized metrics based off of the system’s performance that can be applied to other potential projects. These metrics would then be used to determine, with some accuracy, how much energy savings can be achieved by installing this system. 
 

Q: What are the main challenges to implementing these technologies?
The main challenge comes in building the business case to support the implementation of the technology.

It’s not enough to know that a particular project will save energy, you must also know with accuracy how energy will be saved and how one project’s projected savings compares with other projects competing for time, attention, and slice of the budget.

In building the business case to support a particular technology, there are many questions that must be answered. What was the average energy saved over all the projects using this technology? What was the average cost? What model or method of prediction was used to determine energy savings before undertaking the project? How can I implement this method of prediction to determine an estimate of energy savings for a newly proposed project? All this work is necessary to allow a project manager to effectively decide which energy saving projects to pursue first. Many new technologies don’t have an abundance of historical data to confidently make that case that investment in them will give the highest return. Because of this, the scaled deployment of these technologies may be hindered. Without the proper real world testing and analysis the SPEED program provides, these new technologies could be left out, and some of them could be true game changers in the long run. 
 

Q: What technologies do you believe should SPEED focus on in the coming year?
Demand control kitchen ventilation has proven to be a sure bet when it comes to energy savings and will be the focus of our business case development efforts. Also, RTU optimization retrofit products that utilize VFD’s and advanced controls will be demonstrated. 
 

Q: Where would you like to see the program headed in the future?
Our main goal is to show large scale deployments of energy efficient technologies, and this will continue to be our main push, but in order to make this goal a reality it takes a constant, steady positive stream of data that we can only get from doing more demonstrations and analysis. I would like to see us continue to push for more demonstrations and continue effort to build the solid basis of data and analysis that will make the unmistakable case for system-wide deployment of the most promising and proven technologies. The next part is to create more real world business case studies that more accurately represent real world savings that will result from implementing these technologies. This will give energy managers the necessary tools to accurately estimate their expected savings and ultimately, perpetuate the adoption of these technologies.

 

 


WCEC Research Featured on the Esource Blog

Weatherstripping a home may not be the most captivating of topics, but I’ve found two new methods to air-seal a home this year that really stuck with me, so to speak. One is pretty basic, using a seemingly mundane material—tape. Not just any tape, but a super sticky tape. The Swedish tape manufacturer SIGA  has a line of such tapes designed to stick to and seal just about any seam in a house, whether it’s between two sheets of drywall, between drywall and wood, or around penetrations in the building envelope, including masonry. It has vapor- and non-vapor-permeable options, as well as options for hot surfaces such as those around exhaust flues… Read More

Sac News & Review: The Climate Changers

SN&R writes about 15 scientists and policy makers in the Sacramento region who play vital roles in the global effort to fix a warming planet. Included on that list is WCEC’s very own director, Mark Modera.

Excerpt:

“Making indoor spaces comfortable in an energy-efficient manner is key to lowering emissions of greenhouse gases as well as saving water that will become scarcer as the climate warms. Mark Modera, director of the UC Davis Western Cooling Efficiency Center, is key in this fight. Air conditioning, especially, presents an enormous challenge, since traditional units are among the worst power guzzlers, and as the temperature warms, people will tend to use them more and more. Modera’s research team is also exploring energy-saving strategies for the California Energy Commission, such as hybrid rooftop air conditioners and technology that seals leaks in buildings.”

Read more

Hybrid Indirect-Evaporative Modeling Project Update

Motivation

Conventional, electricity‐powered, Direct‐eXpansion (DX) air conditioners cool the majority of existing buildings in California. Predominantly run during the summer afternoon hours, these DX systems cause significant peak power demand, with a contribution of nearly 30% of the total in California.

What is Indirect Evaporative Cooling

Indirect evaporative cooling (IEC) operates by the same fundamental concept as direct evaporative cooling (evaporating water to cool the air), except that cooling is achieved without adding moisture to the supply air stream. An indirect evaporative heat exchanger (IEHX) is the cooling source for IEC. It typically consists of a series of thin parallel plates assembled to form a multi-layer sandwich of alternating dry and wet channels. The supply air (to room) is cooled in the dry channel (without the addition of moisture) by evaporating water into the (exhaust) air stream in the wet channel and allowing the cool air in the wet channel to absorb heat from the warmer dry channel. In addition to the advantage of not adding moisture, IEC has the potential to ultimately cool the air to its dew point temperature, while direct evaporative cooling or swamp cooling is limited by the wet bulb temperature of the incoming air. The downside of an IEC is that its performance suffers in humid areas where the dry bulb and dew point temperatures are high.

One interesting option to reduce peak power is hybrid cooling – combining an indirect evaporative heat exchanger (IEHX) with a downsized DX system. The hybrid IEC/DX cooler is a promising technology, especially in dry, hot climates like the western US. For example, laboratory testing of a WCEC Western Cooling Challenge certified hybrid IEC/DX cooling system indicates almost 80% energy-use savings and over 60% peak-demand reduction, compared to conventional DX air conditioners. Among the components incorporated into a hybrid IEC/DX system, the IEHX is the critical one, as it is the core technology – the heart of the system.

Though a hybrid IEC/DX cooling system may, if it is properly designed and operated, take both advantages of the IEC (for energy efficient cooling) and the DX (for reliable cool air delivery), existing hybrid cooling systems generally pay the price of larger size and higher cost, resulting in relatively low market penetration. This means their energy saving potential is not fully tapped. Progress on development of IECs is hampered by, among other things:

  • a lack of understanding of the thermal-hydraulic behavior of the core IEHX
  • lack of a practical tool/model for analysis of differing system designs and estimation of their energy saving potential in different climates

This project aims to tap the energy saving potentials of the hybrid IEC/DX cooling system by addressing these two topics through both modeling work and experimental investigations.

Hybrid IEC/DX Systems Modeling
It is clear that the energy savings of a hybrid IEC/DX system will be heavily dependent on its design, configuration, component sizing and modes of operation, as well as the climates in which it operates. Design engineers and utilities urgently need solid, baseline savings data that can be used to analyze designs and to create incentive programs. A practical and accurate model will provide a good solution to this problem. The modeling work focuses on the behavior of the IEHX, given that it is the core of the system and there is a lack of practical models. Once the IEHX model is developed and verified, it will work as a module for system-level modeling of possible hybrid IEC/DX designs.

Thermal Modeling of IEHXs
A practical model for the steady state behaviors of plate IEHXs has been proposed, developed and compared to experimental data.The governing differential equations that describe IEHX heat/mass transfer behavior have been modified to produce a method that is analogous to the effectiveness-NTU method for sensible heat exchangers. The simplified set of equations can then be solved quickly and with numerical stability. Figure 2 shows some initial results where we compare the predictions of this model to experimental data of the IEHX developed by Davis Energy Group.

The main advantage of the proposed model is that the heat transfer performance of an IEHX can rapidly be calculated analytically with high accuracy for various IEHX air flow arrangements (e.g., counter flow and cross flow). This is desirable for a module that is embedded in a system-level hybrid IEC/DX modeling. This body of modeling work has been submitted for journal publication.

Experimental Investigations
The primary objective of the experimental investigation is to advance our understanding of the fluid flows on the IEHX wet channel surfaces in order to maximize heat transfers and minimize pressure drop, which are crucial for designing a highly effective IEHX. The experimental data will also allow further verification of the IEHX model. Since the IEHX is essentially an air-to-air heat exchanger, the pressure loss is as important as heat transfer from the point of view of effectiveness. Our initial experimental work involves measurements of the pressure drop in channels with different surface design patterns (see figure 3) including wicking surface coatings and/or pin-fin surfaces in both dry and wet conditions.

The set-up (figure 4), instrumentation, and benchmark testing of the experimental apparatus have been completed. The test uses counter current air-water flow in a single rectangular channel with a replaceable internal surface to represent the IEHX wet channel. It operates in dry conditions (with the water supply turned off) to simulate the air flow in the dry channel of an IEHX, and in wet conditions to simulate the wet channel. Figure 5 shows an example of the friction factor for a flocked/wicking surface over a range of Reynolds numbers, and a comparison with theoretical predictions. It shows a clear division of the flow regimes from laminar, through the transition region and finally fully turbulent flow. The next stage of the experiment will be to obtain and compare results for different surfaces for both wet and dry conditions. These results will feed back into the model which will be used to predict the pressure loss of different channel and material configurations.

Path Forward
The next step for the modeling work will utilize the verified IEHX model to conduct a more thorough parametric analysis to quantify which factors most significantly influence cooling performance and energy efficiency of the IEHXs so as to provide recommendations for optimizing designs. Next steps for the experimental investigation will be to study additional IEHX surface materials from existing IEHXs to account for the impact of surface patterns on IEHX hydrau¬lic performance, and continue the friction test on the IEHX surfaces in dry and wet condition to get additional data for comparison with the model.

Water Management Milestone Update

Researchers at the WCEC have recently been working to better understand water management strategies to minimize mineral scale formation in evaporative condensers, thus maximizing the evaporative condenser’s long-term performance. This research has included testing using a nominal three-ton evaporative condenser as well as miniature evaporative condensers, where the miniature apparatuses have enables higher throughput. This research has yielded some important insights, most importantly that the optimal bleed rate will be location-specific and dependant on the local water quality, namely magnesium and calcium concentrations; however,

bleed rates that had previously been recommended were likely compromising evaporative condenser performance, and a lower bleed rate (e.g., 15%) will improve the evaporative condenser’s long-term performance.

Experimental results were used to inform a preliminary model, which predicts that evaporative are an appropriate technology for many California water qualities (e.g., predicted life-spans >15 years for most assessed locations). Ongoing research is aiming to elucidate the importance of other water quality parameters such as pH, salinity, and other constituents (e.g., Si, Fe, PO43-, and SO42-).

Simulation of Aerosol Sealant Deposition


 
Thesis Introduction

Recent efforts to improve the energy efficiency of buildings in the US have included efforts to understand and address the tightness of air ducts and building shells. Recorded field measurements tend to show that ductwork in residential and small commercial buildings leaks by approximately 20%. Ayden et al. [13] have shown that the majority of leaks (78-96%) occur at joints in ductwork while the remaining leaks (4-22%) occur along seams. Leaks in the HVAC system and the building envelope result in excess infiltration and exfiltration, which create an increased load on the ventilation, heating and air conditioning equipment. Naturally ventilated buildings require a certain degree of exfiltration and infiltration in order to maintain acceptable indoor air quality, however, national surveys collected by Sherman et al. [15] have shown that less than 10% of US homes meet ASHRAE’s airtightness standard [16].
 
Much research has been conducted on leakage in building ducts and from that research very few innovative methods of sealing those leaks have been developed. One innovative method that has been successfully implemented as a means of sealing duct leaks quickly and efficiently is aerosolized sealants. This method of sealing ducts involves blocking all the inlets and outlets of a duct system, pressurizing the ducting with a fan and then injecting an aerosolized sealant into the ducts. The aerosolized sealant then stays suspended in the air until the flow field inside the duct carries it to a leak where it is deposited. Unlike the traditional method of sealing ducts with tapes and mastics, this method of application is noninvasive and does not require knowledge of the location of the leaks. Aerosolized sealants have been shown by Modera et al. [14] to seal duct leaks in ducts by as much as 86%.
 
Although the use of aerosolized sealants has been proven effective at sealing duct leaks both experimentally and in the field, little is known about the deposition mechanism or the relationship between particle size, streamline characteristics and deposition. These phenomena have proven difficult to explore experimentally because particle deposition occurs on such a small scale and over such a brief amount of time. To overcome the limitations of laboratory instrumentation and observe what actually occurs in the immediate vicinity of the leak as particles approach it, a computational fluid dynamics (CFD) simulation of the sealing process was created.
 
Research has shown that the deposition of small particles suspended in a fluid can be effectively modeled using numerical methods. Ding et al. [21] demonstrated a lattice Boltzmann method for simulating particle dispersion and deposition in laminar flow. Agnihotri et al. [22] investigated three different methods of modeling particle deposition in turbulent flow and validated each with experimental data. This topic of research has encompassed a broad range of applications. Extensive research has been focused on aerosol interactions with the human respiratory system. Tian et al. [23] developed an effective method to numerically simulate the deposition of pharmaceutical aerosols throughout the conducting airways. Liu et al. [24] used numerical simulations to investigate the deposition of aerosols in the human nasal cavity. Guha [25] provides a review of computational methods for simulating particle motion and deposition for both laminar and turbulent flows. The physical understanding of the various transport mechanisms including Brownian and turbulent diffusion, turbophoresis, thermophoresis, inertial impaction, gravitational settling, electrical forces, and the effects of surface roughness are outlined and the numerical methods for simulating them are presented.
 
To facilitate a comparison between the CFD results and experimental data many of the parameters of the apparatus used by Carrié et al [17] in their experiment investigating the deposition of aerosol sealants in joint-type leaks with transverse flow were recreated in the CFD simulation. The geometry of the joint-type leak used is shown in Figure 1.

The experimental apparatus included a 30 cm by 30 cm square duct with a 5 cm long (transverse to the flow), 3 mm wide (parallel to the flow) slot in the wall of the duct. To create a joint-type leak, a block of aluminum with a machined pocket was bolted over the slot. The aluminum block measured 75 mm long (transverse to the flow), 51 mm wide (parallel to the flow) and 2.23 mm tall and the pocket measured 50 mm across (transverse to the flow), 25.5 mm deep (parallel to the flow) and 1.7 mm tall. The flow rate inside the duct was maintained at 42 liters per second (translating to an average velocity of 0.46667 m/s) and the duct pressure was maintained constant. Several duct pressures ranging from 100 to 400 Pa were investigated. The sealant used in the experiment was a water-based vinyl acetate polymer with a density of 982 to 1050 kg/m3, which is what is typically used to seal ducts in practice.
 
Carrié et al [17] found that the joint leak seals due to sealant deposition 1 to 2 mm inside the inlet to the joint leak. Their results included particle diameter distributions obtained from a cascade impactor, sealing profiles of flow rate through the leak versus time over the course of the sealing process and overall deposition efficiencies. Their results for pressure drops across the leak ranging from 100 to 400 Pa indicate that pressure variations do not have a significant effect on the deposition efficiency.
 
The aim of the CFD simulation is to provide greater resolution of information on the deposition mechanisms. In the investigation of the deposition Carrié was required to dismantle the apparatus and remove the sealant plug in order to measure the amount of sealant deposited. Consequently, the experiment had to be terminated every time that a measurement was taken, thus only single point measurements were possible. Using CFD, the investigation can focus on the change over time in the deposition locations, rates and efficiency as well as changes to the flow as the leak is sealed.
 
Additionally, the use of numerical methods provides the opportunity to investigate the relationship between particle diameter, streamline characteristics and deposition. Since the generation of a mono-disperse aerosol is not feasible these relationships are unclear in experimental data. Using numerical methods a single particle can be traced from its point of injection, through the flow and to the location of deposition (if the particle deposits). By specifying the diameter and injection point of each particle and determining if and where they deposit the relationships between these three parameters can be determined.

Newsletter: Western Cooling Connection Update | October 30th, 2012

WCEC has made some major milestones recently including verification of Trane’s Voyager DC passing the Western Cooling Challenge, and the behavioral research team has finalized their report. Read about these projects and more in our latest newsletter update:

Western Cooling Connection Update | October 30th, 2012

Phase-Change Materials for Hydronic Systems Update

This project aims to reduce the running costs of hydronic heating and cooling systems in commercial buildings by reducing the pumping power. Pumping power can be reduced by lowering the required flow rate of the heat transfer fluid. However, maintaining capacity while reducing the flow rate requires an increase in the heat capacity of the fluid. Ice slurries have been used to do this in cooling applications, but while ice has a high latent heat of fusion (334 kJ/kg) and effectively increases the heat capacity of water, its use is limited by its fixed melting temperature. In order to address this limitation, we are investigating the use of phase change materials (PCMs) in hydronic systems.
 

PCMs have great potential for thermal energy storage. There are a wide range of applications of PCMs, ranging from building materials to clothing. The advantage of using PCMs rather than ice is that they can be engineered to melt at any desired temperature which facilitates their integration into existing systems.
 

The most promising PCMs are based on paraffin waxes due to their combination of a wide range of melting temperatures, high latent heats, low cost, and chemical stability.

To use these waxes in hydronic systems, we need to know how they behave when mixed with water. The simplest way is to create an emulsion, but this is likely to result in the wax depositing on the pipes, valves, and pump, causing loss of efficiency and capacity, as well as possible equipment failure. So the PCM needs to be physically isolated from the fluid. This is accomplished by encapsulating it.
 

Microencapsulation is generally classified as encapsulation of a substance with a diameter between 1-100 microns. Larger than this and the particles are considered to be macroencapsulated. The benefits of PCM microencapsulation in hydronic systems are multiple:

  • 1. The smaller size helps maximize the surface to volume ratio thereby reducing the time it takes for the particles to melt or freeze. This is particularly significant in view of the poor thermal conductivity of solid paraffin wax.
  • 2. Smaller particles are less likely to be trapped by pump impellors or valves, and so are less likely to rupture and release paraffin into the water, leading to potential failure

 
Behavior of Slurries
A mixture of microencapsulated PCM and water will act like a slurry. The increased viscosity of the slurry may offset some or all of the pump energy savings due to the lower flow rate, and the heat transfer behavior will be different from pure water. We have modeled the behavior of PCM slurries with varying fractions of PCM. Typical behavior is shown in the graph to the left where we have modeled a 4 ton system.
 

The reduction in pumping power is easy to see. The sharp drop in slurry flow rate and pumping power at a concentration of ≈ 0.08 is due the transition from laminar to turbulent flow. The model uses data for a commercially available microencapsulated PCM (made by Microtek) which has a melting point of 133ºF and a latent heat of 73BTU/lb.
 

Path Forward
Hydronic System Model
The goal of this experiment is to determine the performance of PCMs in a hydronic system. We are building a test set up in our laboratory which will replicate the behavior of a 2 ton heating and cooling system, shown in the PCM schematic on the left. A supply of conditioned air will provide a load to a fan coil, and a water to slurry heat exchanger will regenerate the PCM. The experiment will consist of 4 phases. The first phase will consist of pumping pure water to determine the pumping power required if the system did not include PCMs. The second phase consists of testing the slurry under heating conditions using a PCM with a phase change temperature of approximately 140°F. Then a different PCM with a lower phase change temperature (~50°F) will be used to create another slurry which will be tested under cooling conditions and finally a slurry containing PCMs with both high and low melting points will be used to simulate a 2 pipe system. The slurry will pass through a loop where it will go through a conditioning phase in the first heat exchanger. In the second heat exchanger the slurry will exchange heat with air which will be delivered to the room. The air will also need to be pre-conditioned to meet the standard temperatures for HVAC testing. Cold and hot water supplies on site will be used to pre-condition the slurry and the outdoor air.
 

During this experiment we will subject the PCM microcapsules to both thermal cycling and mechanical stresses. In order to separate any effects, we will also conduct two other experiments in which we subject the PCM capsules to only one variable: thermal or mechanical stress.
 

Pumping experiment
To determine the mechanical stability of the PCMs, a test will pump the PCM slurry in a closed loop. Samples will be taken periodically and studied to determine if any capsules have ruptured. The samples will be photographed, and imaging software will be used to determine the range of diameters before and after the pumping test. This will give an indication as to whether different sizes of capsules are more susceptible to rupture than others.
 

Thermal Cycling experiment
In order for the PCMs to remain useful in our application, their thermal properties need to remain constant after repeated cycling. The literature suggests that paraffin based PCMs are generally thermally stable. A thermal cycling test will measure the change in thermal properties such as melting temperature and heat of fusion, after repeated cycling. A sample of the slurry will be placed in a sealed container and thermally cycled between temperatures 10°F above and below the phase change temperature. Samples will be periodically removed from the container for testing by Differential Scanning Calorimetry.

 

 


Behavioral Research Team Releases Final Report

The HVAC Behavioral Research Initiative (HBRI) is excited to announce the release of its final report on the contractor and technician behavior study. The WCEC led the field observation part of the study, which looked directly at what technicians do when they respond to an HVAC maintenance service call. The study was conducted using an innovative method of undisclosed participant observation, followed by semi-structured interviews.
 

Posing as homeowners, HBRI’s lead Claudia Barriga and Verified, Inc’s lead trainer Robert Eshom called a number of contractors, and scheduled maintenance services for their “home”. The house used belonged to a research ally, and had a perfectly functioning HVAC system. When a technician came to provide the maintenance service, the “homeowners” showed him the AC system and explained that they didn’t know if the system was working correctly or efficiently. Then, they proceeded to observe the kind of service, diagnostics, explanations and repair offers that the technician provided. After the work was completed, (which did not include any actual modifications to the system, only recommendations for service), the technicians were paid, and then the “homeowners” revealed themselves to be researchers. The technicians were offered $100 for consenting to let the researchers use the observation for the research, and participate in a post-observation interview. Of the 16 technicians who were called, 13 allowed the researchers to use the observations, and 9 gave the researchers in-depth interviews.

While a sample size of 13 is certainly not sufficient to generalize to all technicians, it was an eye-opening study.

None of the technicians provided a service that remotely resembled ACCA Standard 4—the industry standard for what maintenance services are supposed to accomplish. In fact, none of them knew what ACCA Standard 4 was.

The figure shows which ACCA 4 tasks were completed correctly, which were attempted but not completed correctly, and which were not attempted at all. One technician did do several of the tasks that were expected, but most technicians did not attempt many of the tasks, or completed them incorrectly. One technician did not attempt to do any of the expected tasks. There was no relationship between the number of tasks completed correctly and the cost of the service (which ranged from $60 to $180), nor to the years of experience of the technician (which ranged from 1 to 26 years). There was something of a correlation to the duration of the service: it is simply not possible to do many of the ACCA 4 tasks within the 23 – 90 minutes most technicians had available.
 

Technicians were also observed to be consistently discouraging discussions about energy efficient upgrades. As “homeowners”, the researchers made increasing efforts to ask for energy efficiency optimization services, recommendations or possible upgrades. These efforts did not result in more thorough maintenance services. Moreover, technicians often stated that such things were “not necessary” or “not worth it”.
 

Maintenance is key to achieving cooling related energy goals in California. It has been shown to have the potential to save up to 30% of a typical air conditioner’s energy use and peak demand. But just as significantly, understanding the relationship between building owners and their service technicians sheds light on that magic moment when an HVAC system is not performing well and should be replaced with something, hopefully something efficient. The penetration of energy efficient technologies and services is significantly influenced by service technicians and contractors. In this case, the service that was provided would not have resulted in direct energy savings, and it did not provide some of the relationship-building elements that can lead to energy efficient choices. Were the technicians less than competent, or worse, lazy? Findings from the interviews indicate that this was not the case. Technicians were well trained and had the ability to perform at higher levels than they did. They were also proud of their abilities and training, and interested in providing good services to customers.
 

They simply did not have the time to do the job correctly. The way the industry and their specific job is structured provides no incentives for them to perform services up to ACCA 4 standards, or to promote energy efficient solutions and upgrades.
 

Overall, the conclusions drawn from this study were:

  • Technical performance by the observed technicians was below the standards of ACCA Standard 4. Yet, the technicians seemed to be more knowledgeable than their technical performance scores would suggest, and all seemed confident and proud of their work.
  • In general, technicians work hard to achieve their perceived company and customer goals: accomplish as many service calls as possible in one day. Industry transformation should include a way to make technicians see the non-traditional goals of quality technical performance as consistent with the goals of their employers and their customers.
  • There is a need to structure an industry system in which hard-won skills can be put to use, requiring competent technicians to “push” well-documented benefits, as well as early-adopter customers to value and “pull” the benefits. Technicians and contractors may also need to develop the skills to recognize and respond to this customer pull, a skill that was completely absent in our observations.
    This study was funded by the California IOUs and the CPUC, and the prime contractor was Energy Market Innovations (EMI). The overall project included also a major survey of HVAC contractors throughout California (led by EMI), which provides a very interesting contrast with the technician observation part of the study. Complete findings and analyses for both parts of the project are documented in a report entitled “California HVAC Contractor & Technician Behavior Study–Final Report”, released in September and available at CALMAC Study ID SCE0323.01

 

 


Western Cooling Challenge Certifies Trane’s Voyager DC

Western Cooling Challenge Certifies Trane’s Voyager DC

 

In an effort to advance commercial air conditioning equipment that operates more efficiently in hot dry climates such as California, Trane developed a hybrid rooftop air conditioner that utilizes indirect evaporative cooling to increase cooling capacity and reduce peak electrical demand by 40%.
 
The equipment was laboratory tested by the UC Davis Western Cooling Efficiency Center, and has been certified to pass the rigorous Western Cooling Challenge performance requirements. Trane is now the second manufacturer to achieve UC Davis’ Challenge certification, an effort sponsored by Southern California Edison, California Energy Commission and Pacific Gas & Electric.
 
“Many are not yet aware that new electric utility rates will saddle commercial building owners with large additional charges for power used during peak periods. Since air conditioning is the largest portion of electricity used at these times, the potential for 40% savings is enormous,” said Jonathan Woolley of the UC Davis Western Cooling Efficiency Center. “Trane’s Voyager DC met our performance goals on the mark, and promises to be one of the most cost effective ‘climate-appropriate’ cooling technologies available for commercial buildings”.
 
The California Public Utility Commission’s Statewide Energy Efficiency Strategic Plan demands the rapid commercialization of cooling technologies that are adapted for hot-dry climates. The plan specifies that 70% of air conditioners installed in 2020 should be “climate appropriate”.
 
Trane’s Voyager DC uses water evaporation to cool the condenser on an otherwise conventional air conditioner. It then uses the water chilled by evaporation to cool the hot outside air used for fresh air building ventilation. These techniques increase the number of hours a system can use “free-cooling” to cool a space with outside air, and dramatically reduce the amount of time a system operates at full speed. In addition to capturing large savings at peak operating conditions, the Trane Voyager DC incorporates variable speed fans, staged compressors, and other measures to maintain high efficiency operation at part load conditions.
 
Launched in June 2008, the UC Davis Western Cooling Challenge is a program designed to help HVAC manufacturers deliver ‘climate appropriate’ cooling technologies. The program evaluates equipment performance through laboratory and field tests, and assists utilities, engineers, and customers in applying the technologies.

About the Western Cooling Efficiency Center

The Western Cooling Efficiency Center is a key component of the UC Davis Energy Efficiency Center (EEC), which was founded in 2006 with support from the California Clean Energy Fund (CalCEF). The Center is supported by industry affiliates, including utilities, manufacturers, contractors and the California Energy Commission. Its mission is to partner with stakeholders to identify technologies, disseminate information and implement programs that reduce cooling-system electrical demand and energy consumption in the Western United States. wcec.ucdavis.edu

About Trane

Trane is a major global HVAC manufacturer, with a diverse portfolio of products and services related to HVAC, energy conservation, and renewable energy. A subsidiary of Ingersoll Rand, Trane has been manufacturing HVAC equipment for more than 100 years. With technologies and expertise in the field of energy, Trane also manages various energy efficiency programs for utilities, and supports financing solutions to advance the application of energy and cost saving measures. Trane.com

About UC Davis

For more than a century, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has 31,000 students, an annual research budget that exceeds $500 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science — and advanced degrees from six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing. UC Davis

Media contact(s):

 

 

Aerosol Building Envelope Sealing Demonstration


Effective Envelope Sealing

description

First field test to see if an aerosol-based sealant can quickly, and sufficiently seal building envelope leaks.

Aerosol Sealants: A Proven Technology
Today, aerosol-based sealing solutions such as Aeroseal are a proven, effective method for sealing leaks in specific applications. Aeroseal is a system that uses an aerosol-based sealant mist to seal the many leaks in ductwork. This technology works fast, doesn’t require a contractor to crawl through attics or punch holes in walls and the simple payback can be in less than two years. No wonder ‘This Old House Magazine’ awarded Aeroseal Best New Home Product of 2011.

What if we could apply the same basic idea of using aerosolized particles to seal leaks and map that onto a building’s entire envelope? WCEC is actively working to answer this question by testing aerosolized-based envelope sealing in a few test homes.

The First Ever Aerosol-Based Residential Envelope Sealing Test
Stockton, CA—With the help of Habitat for Humanity and CONSOL Energy, WCEC gained access to a new home at the rough-in building stage. Engineer Curtis Harrington along with graduate student Nelson Dichter, began the preparations for sealing the home’s envelope. They taped off areas that they didn’t want sealed such as the interior door jambs, HVAC ducts and the inside of double-hung windows. Once taping was complete, they lined the floors with plastic sheeting to prevent any sealant from sticking to the concrete floor. After the initial preparation, the engineers assembled and installed a blower door to the interior door in the garage, then turned on a high-powered heater to churn out hot air to heat the rooms, promoting a quicker drying process for the aerosol particles.

“So you can see here when the room begins to gain pressure. This means that the aerosol particles have found their way to the leaks in that room. We aren’t entirely sure when all of the potential leaks are sealed, but when the pressure stops changing significantly we will begin moving the aerosol nozzle from room to room.” Said Curtis.

Some Preliminary Results and Observations
“Since this is a first ever real-world test of this system and we are unable to reach the optimum nozzle pressure, we are erring on the side of restraint—using the sealant sparingly and moving the delivery device frequently until we know how much of it ends up on the floors or walls. If it doesn’t coat the walls or floors and doesn’t seal the majority of the leaks, we will test this system again in a new house (with new compressor fittings) and increase the sealant flow rate to speed up the sealing process.”

After collecting sufficient data, the engineers opened doors and windows to evacuate any stray aerosol particles.

What the engineers really wanted to know upon first inspection: Did the aerosol particles coat the walls or the floors? “I was extremely relieved to see that there was virtually no residual aerosol particles on any of the walls or floors except for a very minor amount of stickiness on the floor in one room,” said Curtis. “These results are very promising, and we believe if the sealing wasn’t substantial that we can safely try for more aggressive sealing goals in a future test.”

Back at the lab, WCEC preliminary data shows an almost 30% reduction in the test home’s leaks. “We are still working out our findings for our report, but we are confident that, with some process changes (and a properly working air compressor) we can achieve an envelope sealing effectiveness of 50% or more. We are even considering using this system to seal duct leaks at the same time. “ Said Curtis. But residential envelope sealing is just the beginning. Once WCEC has refined the process for residential homes, WCEC hopes to see similar results in commercial applications. “If we can reach these goals, this technology can have a significant impact on energy savings in both residential and
commercial sectors.”

description

Previous WCEC News

October Newsletter Update

WCEC has made some major milestones recently including verification of Trane’s Voyager DC passing the Western Cooling Challenge, and the behavioral research team has finalized their report. Read about these projects and more in our latest newsletter update:

Western Cooling Connection Update | October 30th, 2012


Phase-Change Materials Research Update

This project aims to reduce the running costs of hydronic heating and cooling systems in commercial buildings by reducing the pumping power. Pumping power can be reduced by lowering the required flow rate of the heat transfer fluid. However, maintaining capacity while reducing the flow rate requires an increase in the heat capacity of the fluid. Ice slurries have been used to do this in cooling applications, but while ice has a high latent heat of fusion (334 kJ/kg) and effectively increases the heat capacity of water, its use is limited by its fixed melting temperature. In order to address this limitation, we are investigating the use of phase change materials (PCMs) in hydronic systems.
PCMs have great potential for thermal energy storage. There are a wide range of applications of PCMs, ranging from building materials to clothing. The advantage of using PCMs rather than ice is that they can be engineered to melt at any desired temperature which facilitates their integration into existing systems.

The most promising PCMs are based on paraffin waxes due to their combination of a wide range of melting temperatures, high latent heats, low cost, and chemical stability.

To use these waxes in hydronic systems, we need to know how they behave when mixed with water. The simplest way is to create an emulsion, but this is likely to result in the wax depositing on the pipes, valves, and pump, causing loss of efficiency and capacity, as well as possible equipment failure. So the PCM needs to be physically isolated from the fluid. This is accomplished by encapsulating it.
Microencapsulation is generally classified as encapsulation of a substance with a diameter between 1-100 microns. Larger than this and the particles are considered to be macroencapsulated. The benefits of PCM microencapsulation in hydronic systems are multiple:

  • 1. The smaller size helps maximize the surface to volume ratio thereby reducing the time it takes for the particles to melt or freeze. This is particularly significant in view of the poor thermal conductivity of solid paraffin wax.
  • 2. Smaller particles are less likely to be trapped by pump impellors or valves, and so are less likely to rupture and release paraffin into the water, leading to potential failure

Behavior of Slurries

A mixture of microencapsulated PCM and water will act like a slurry. The increased viscosity of the slurry may offset some or all of the pump energy savings due to the lower flow rate, and the heat transfer behavior will be different from pure water. We have modeled the behavior of PCM slurries with varying fractions of PCM. Typical behavior is shown in the graph to the left where we have modeled a 4 ton system.
The reduction in pumping power is easy to see. The sharp drop in slurry flow rate and pumping power at a concentration of ≈ 0.08 is due the transition from laminar to turbulent flow. The model uses data for a commercially available microencapsulated PCM (made by Microtek) which has a melting point of 133ºF and a latent heat of 73BTU/lb.
Path Forward

Hydronic System Model
The goal of this experiment is to determine the performance of PCMs in a hydronic system. We are building a test set up in our laboratory which will replicate the behavior of a 2 ton heating and cooling system, shown in the PCM schematic on the left. A supply of conditioned air will provide a load to a fan coil, and a water to slurry heat exchanger will regenerate the PCM. The experiment will consist of 4 phases. The first phase will consist of pumping pure water to determine the pumping power required if the system did not include PCMs. The second phase consists of testing the slurry under heating conditions using a PCM with a phase change temperature of approximately 140°F. Then a different PCM with a lower phase change temperature (~50°F) will be used to create another slurry which will be tested under cooling conditions and finally a slurry containing PCMs with both high and low melting points will be used to simulate a 2 pipe system. The slurry will pass through a loop where it will go through a conditioning phase in the first heat exchanger. In the second heat exchanger the slurry will exchange heat with air which will be delivered to the room. The air will also need to be pre-conditioned to meet the standard temperatures for HVAC testing. Cold and hot water supplies on site will be used to pre-condition the slurry and the outdoor air.
During this experiment we will subject the PCM microcapsules to both thermal cycling and mechanical stresses. In order to separate any effects, we will also conduct two other experiments in which we subject the PCM capsules to only one variable: thermal or mechanical stress.
Pumping experiment
To determine the mechanical stability of the PCMs, a test will pump the PCM slurry in a closed loop. Samples will be taken periodically and studied to determine if any capsules have ruptured. The samples will be photographed, and imaging software will be used to determine the range of diameters before and after the pumping test. This will give an indication as to whether different sizes of capsules are more susceptible to rupture than others.
Thermal Cycling experiment
In order for the PCMs to remain useful in our application, their thermal properties need to remain constant after repeated cycling. The literature suggests that paraffin based PCMs are generally thermally stable. A thermal cycling test will measure the change in thermal properties such as melting temperature and heat of fusion, after repeated cycling. A sample of the slurry will be placed in a sealed container and thermally cycled between temperatures 10°F above and below the phase change temperature. Samples will be periodically removed from the container for testing by Differential Scanning Calorimetry.

 

 


Behavioral Research Update

The HVAC Behavioral Research Initiative (HBRI) is excited to announce the release of its final report on the contractor and technician behavior study. The WCEC led the field observation part of the study, which looked directly at what technicians do when they respond to an HVAC maintenance service call. The study was conducted using an innovative method of undisclosed participant observation, followed by semi-structured interviews.
Posing as homeowners, HBRI’s lead Claudia Barriga and Verified, Inc’s lead trainer Robert Eshom called a number of contractors, and scheduled maintenance services for their “home”. The house used belonged to a research ally, and had a perfectly functioning HVAC system. When a technician came to provide the maintenance service, the “homeowners” showed him the AC system and explained that they didn’t know if the system was working correctly or efficiently. Then, they proceeded to observe the kind of service, diagnostics, explanations and repair offers that the technician provided. After the work was completed, (which did not include any actual modifications to the system, only recommendations for service), the technicians were paid, and then the “homeowners” revealed themselves to be researchers. The technicians were offered $100 for consenting to let the researchers use the observation for the research, and participate in a post-observation interview. Of the 16 technicians who were called, 13 allowed the researchers to use the observations, and 9 gave the researchers in-depth interviews.

While a sample size of 13 is certainly not sufficient to generalize to all technicians, it was an eye-opening study.

None of the technicians provided a service that remotely resembled ACCA Standard 4—the industry standard for what maintenance services are supposed to accomplish. In fact, none of them knew what ACCA Standard 4 was.

The figure shows which ACCA 4 tasks were completed correctly, which were attempted but not completed correctly, and which were not attempted at all. One technician did do several of the tasks that were expected, but most technicians did not attempt many of the tasks, or completed them incorrectly. One technician did not attempt to do any of the expected tasks. There was no relationship between the number of tasks completed correctly and the cost of the service (which ranged from $60 to $180), nor to the years of experience of the technician (which ranged from 1 to 26 years). There was something of a correlation to the duration of the service: it is simply not possible to do many of the ACCA 4 tasks within the 23 – 90 minutes most technicians had available.
Technicians were also observed to be consistently discouraging discussions about energy efficient upgrades. As “homeowners”, the researchers made increasing efforts to ask for energy efficiency optimization services, recommendations or possible upgrades. These efforts did not result in more thorough maintenance services. Moreover, technicians often stated that such things were “not necessary” or “not worth it”.
Maintenance is key to achieving cooling related energy goals in California. It has been shown to have the potential to save up to 30% of a typical air conditioner’s energy use and peak demand. But just as significantly, understanding the relationship between building owners and their service technicians sheds light on that magic moment when an HVAC system is not performing well and should be replaced with something, hopefully something efficient. The penetration of energy efficient technologies and services is significantly influenced by service technicians and contractors. In this case, the service that was provided would not have resulted in direct energy savings, and it did not provide some of the relationship-building elements that can lead to energy efficient choices. Were the technicians less than competent, or worse, lazy? Findings from the interviews indicate that this was not the case. Technicians were well trained and had the ability to perform at higher levels than they did. They were also proud of their abilities and training, and interested in providing good services to customers.
They simply did not have the time to do the job correctly. The way the industry and their specific job is structured provides no incentives for them to perform services up to ACCA 4 standards, or to promote energy efficient solutions and upgrades.
Overall, the conclusions drawn from this study were:

  • Technical performance by the observed technicians was below the standards of ACCA Standard 4. Yet, the technicians seemed to be more knowledgeable than their technical performance scores would suggest, and all seemed confident and proud of their work.
  • In general, technicians work hard to achieve their perceived company and customer goals: accomplish as many service calls as possible in one day. Industry transformation should include a way to make technicians see the non-traditional goals of quality technical performance as consistent with the goals of their employers and their customers.
  • There is a need to structure an industry system in which hard-won skills can be put to use, requiring competent technicians to “push” well-documented benefits, as well as early-adopter customers to value and “pull” the benefits. Technicians and contractors may also need to develop the skills to recognize and respond to this customer pull, a skill that was completely absent in our observations.
    This study was funded by the California IOUs and the CPUC, and the prime contractor was Energy Market Innovations (EMI). The overall project included also a major survey of HVAC contractors throughout California (led by EMI), which provides a very interesting contrast with the technician observation part of the study. Complete findings and analyses for both parts of the project are documented in a report entitled “California HVAC Contractor & Technician Behavior Study–Final Report”, released in September and available at CALMAC Study ID SCE0323.01

 

 


 

 

Western Cooling Challenge Certifies Trane’s Voyager DC

 

In an effort to advance commercial air conditioning equipment that operates more efficiently in hot dry climates such as California, Trane developed a hybrid rooftop air conditioner that utilizes indirect evaporative cooling to increase cooling capacity and reduce peak electrical demand by 40%.
The equipment was laboratory tested by the UC Davis Western Cooling Efficiency Center, and has been certified to pass the rigorous Western Cooling Challenge performance requirements. Trane is now the second manufacturer to achieve UC Davis’ Challenge certification.
“Many are not yet aware that new electric utility rates will saddle commercial building owners with large additional charges for power used during peak periods. Since air conditioning is the largest portion of electricity used at these times, the potential for 40% savings is enormous,” said Jonathan Woolley of the UC Davis Western Cooling Efficiency Center. “Trane’s Voyager DC met our performance goals on the mark, and promises to be one of the most cost effective ‘climate-appropriate’ cooling technologies available for commercial buildings”.
The California Public Utility Commission’s Statewide Energy Efficiency Strategic Plan demands the rapid commercialization of cooling technologies that are adapted for hot-dry climates. The plan specifies that 70% of air conditioners installed in 2020 should be “climate appropriate”.
Trane’s Voyager DC uses water evaporation to cool the condenser on an otherwise conventional air conditioner. It then uses the water chilled by evaporation to cool the hot outside air used for fresh air building ventilation. These techniques increase the number of hours a system can use “free-cooling” to cool a space with outside air, and dramatically reduce the amount of time a system operates at full speed. In addition to capturing large savings at peak operating conditions, the Trane Voyager DC incorporates variable speed fans, staged compressors, and other measures to maintain high efficiency operation at part load conditions.
Launched in June 2008, the UC Davis Western Cooling Challenge is a program designed to help HVAC manufacturers deliver ‘climate appropriate’ cooling technologies. The program evaluates equipment performance through laboratory and field tests, and assists utilities, engineers, and customers in applying the technologies.
About the Western Cooling Efficiency Center
The Western Cooling Efficiency Center is a key component of the UC Davis Energy Efficiency Center (EEC), which was founded in 2006 with support from the California Clean Energy Fund (CalCEF). The Center is supported by industry affiliates, including utilities, manufacturers, contractors and the California Energy Commission. Its mission is to partner with stakeholders to identify technologies, disseminate information and implement programs that reduce cooling-system electrical demand and energy consumption in the Western United States. wcec.ucdavis.edu

About Trane
Trane is a major global HVAC manufacturer, with a diverse portfolio of products and services related to HVAC, energy conservation, and renewable energy. A subsidiary of Ingersoll Rand, Trane has been manufacturing HVAC equipment for more than 100 years. With technologies and expertise in the field of energy, Trane also manages various energy efficiency programs for utilities, and supports financing solutions to advance the application of energy and cost saving measures. Trane.com

About UC Davis
For more than a century, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has 31,000 students, an annual research budget that exceeds $500 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science — and advanced degrees from six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing. UC Davis
Media contact(s):

 

 

Effective Envelope Sealing

 

04/27/2012

First field test to see if an aerosol-based sealant can quickly, and sufficiently seal building envelope leaks.

Aerosol Sealants: A Proven Technology

Today, aerosol-based sealing solutions such as Aeroseal are a proven, effective method for sealing leaks in specific applications. Aeroseal is a system that uses an aerosol-based sealant mist to seal the many leaks in ductwork. This technology works fast, doesn’t require a contractor to crawl through attics or punch holes in walls and the simple payback can be in less than two years. No wonder ‘This Old House Magazine’ awarded Aeroseal Best New Home Product of 2011.

What if we could apply the same basic idea of using aerosolized particles to seal leaks and map that onto a building’s entire envelope? WCEC is actively working to answer this question by testing aerosolized-based envelope sealing in a few test homes.

The First Ever Aerosol-Based Residential Envelope Sealing Test

Stockton, CA—With the help of Habitat for Humanity and CONSOL Energy, WCEC gained access to a new home at the rough-in building stage. Engineer Curtis Harrington along with graduate student Nelson Dichter, began the preparations for sealing the home’s envelope. They taped off areas that they didn’t want sealed such as the interior door jambs, HVAC ducts and the inside of double-hung windows. Once taping was complete, they lined the floors with plastic sheeting to prevent any sealant from sticking to the concrete floor. After the initial preparation, the engineers assembled and installed a blower door to the interior door in the garage, then turned on a high-powered heater to churn out hot air to heat the rooms, promoting a quicker drying process for the aerosol particles.

“So you can see here when the room begins to gain pressure. This means that the aerosol particles have found their way to the leaks in that room. We aren’t entirely sure when all of the potential leaks are sealed, but when the pressure stops changing significantly we will begin moving the aerosol nozzle from room to room.” Said Curtis.

Some Preliminary Results and Observations

“Since this is a first ever real-world test of this system and we are unable to reach the optimum nozzle pressure, we are erring on the side of restraint—using the sealant sparingly and moving the delivery device frequently until we know how much of it ends up on the floors or walls. If it doesn’t coat the walls or floors and doesn’t seal the majority of the leaks, we will test this system again in a new house (with new compressor fittings) and increase the sealant flow rate to speed up the sealing process.”

After collecting sufficient data, the engineers opened doors and windows to evacuate any stray aerosol particles.

What the engineers really wanted to know upon first inspection: Did the aerosol particles coat the walls or the floors? “I was extremely relieved to see that there was virtually no residual aerosol particles on any of the walls or floors except for a very minor amount of stickiness on the floor in one room,” said Curtis. “These results are very promising, and we believe if the sealing wasn’t substantial that we can safely try for more aggressive sealing goals in a future test.”

Back at the lab, WCEC preliminary data shows an almost 30% reduction in the test home’s leaks. “We are still working out our findings for our report, but we are confident that, with some process changes (and a properly working air compressor) we can achieve an envelope sealing effectiveness of 50% or more. We are even considering using this system to seal duct leaks at the same time. “ Said Curtis. But residential envelope sealing is just the beginning. Once WCEC has refined the process for residential homes, WCEC hopes to see similar results in commercial applications. “If we can reach these goals, this technology can have a significant impact on energy savings in both residential and

commercial sectors.”

 

 

WCEC 2011-2012 Annual Report on Cooling in the West

 

Read about all the major projects currently being researched at WCEC here: WCEC 2011-2012 Annual Report

(NOTE: File is 11MB)

 

Water-Cooled Condensers: Longevity Research Update

 


The process of evaporating water to cool the air works extremely well in hot-dry climates. This technology works with commercial systems that already have the proper supply and ventilation duct work installed, but in residential applications, systems are mostly designed with a standard vapor-compression system in mind­­—ventilation and exhaust ducts just aren’t present in most single-family homes.

Water-cooled condenser units utilize the same energy efficient process of evaporation, but instead of cooling the supply air, they reduce the temperature on the condenser (refrigerant) coil. This increases the efficiency of the condensing cycle that requires the heavy expulsion of thermal energy to cool the refrigerant. This technology has shown to have a great impact on energy savings: between 30-50% reduction in energy used for cooling.

The main challenge for this technology is the creation of scale on the coil from the evaporation process. Before water-cooled condensers become a household name, they must prove that they can last years of harsh conditions without significant issues. Research on the longevity of water-cooled condensers is in the final stages of testing 4 different treatment methods that look to increase the lifespan of these products significantly and reduce overall water consumption.

 

By lowering the bleed amount, WCEC saves over 50% more water while retaining the same efficiency and longevity as the manufacturer’s bleed specifications.

 

Interesting findings:

      » Large scale build-up on condenser coil reduces efficiency by approximately 30%
      » The pumps are the components that cause the system to fail due to clogging/breaking from scale build-up
    » WCEC tested 4 different treatment methods
Download the latest Water-Cooled Condenser Longevity presentation update here

 

 

WCEC Engineer Interviewed in the Sacramento Business Journal

 

WCEC’s own Jonathan Woolley talks about Seeley’s Climate Wizard and the future of evaporative cooling as a high efficiency alternative to standard air conditioners.

Read a preview of the article here

Jonathan Woolley gave a SMUD presentation on evaporative technologies on July 19th and was featured again in the Sacramento Business Journal.

Read the article here

 

 

Behavioral Research Initiative Update

 

Read the latest article on WCEC’s behavioral research and learn about how contractors and end-users interact with HVAC technologies.

Go to our behavioral research page to learn more about what our projects are up to and what others have done in this field of study.

 

 

Western Cooling Connection Newsletter Update | May 2012

 

Read about the latest happenings at WCEC including:

  • 2012 WCEC Affiliates Forum
  • PBS Video featuring WCEC Director Mark Modera
  • Western Cooling Challenge Update
  • HVAC Behavioral Research Initiative

Read the Newsletter Update

 

 

PBS Interview with WCEC Director, Mark Modera

 

Aired on April 18th, 2012

Program: Office of the Future

Episode: Energy-Efficient Office Space

Office of the Future is an intriguing look at how designers, architects, engineers and builders are redesigning commercial office space throughout Southern California. The program explores how innovative and interactive lighting systems can lower operating costs and create a more comfortable and productive work environment.

Watch the video

 

 

WCEC 2012 Affiliates Forum: Exploring the barriers and solutions for HVAC energy efficiency acceptance

 

WCEC Affiliates Forum 2012

Exploring the barriers and solutions for HVAC energy efficiency acceptance from the perspectives of Manufacturers, Installers, Utilities, and Governing Entities. Join WCEC in a gathering of professionals from all corners of the HVAC industry to examine the issues of HVAC energy efficiency acceptance. Network with other industry leaders and contribute to the overarching goal of moving today’s energy efficient technologies into the marketplace.

 


Speaker Presentations

 

Mark Modera | Director | WCEC: Introduction to the Forum and some highlights from the WCEC.

PDF presentation download

Chris Scruton | Project Manager | CEC: Barriers and solutions to HVAC energy efficiency from the State perspective.

PDF presentation download

Nate Taylor | Engineer | Sempra Energy: Barriers and Solutions to HVAC Energy Efficiency Acceptance in the Commercial/Multi-Tenant Light Commercial Sectors from a utility perspective

PDF presentation download

Keith Forsman | Senior Product Manager | PG&E: Barriers and Solutions to HVAC Energy Efficiency Acceptance in the Commercial/Multi-Tenant Light Commercial Sectors from a utility perspective

PDF presentation download

Jerine Ahmed | Senior Engineer | SCE: Barriers and Solutions to HVAC Energy Efficiency Acceptance in the Residential Market from a utility perspective

PDF presentation download

Richard Lord | Fellow | Carrier: Barriers and Solutions to HVAC Energy Efficiency Acceptance from a large manufacturer perspective

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Tim Heaton | Vice President | Coolerado: Barriers and Solutions to HVAC Energy Efficiency Acceptance from a manufacturer perspective

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Rick Wylie | President | Beutler: Barriers and Solutions to HVAC Energy Efficiency Acceptance from an installer/contractor perspective

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Dick Bourne | President | Integrated Comfort Inc.: Efficiency as generation

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WCEC’s Director Given Prestigious ASHRAE Fellow Award

 

03/12/2012

Mark Modera accepting ASHRAE Fellow Honor

I am honored to be recognized by ASHRAE as a fellow. I plan to continue my work in HVAC research and technology development in support of ASHRAE, through my efforts at the Western Cooling Efficiency Center and as a Professor of Mechanical Engineering and Environmental Engineering at UC Davis.”

—Mark Modera, WCEC Director

Thirty-six people are being recognized by ASHRAE for their contributions to the Society and the building industry at the Society’s 2012 Winter Conference held Jan. 21-25.

 

Fellow ASHRAE is a membership grade that recognizes distinction in the arts and sciences of environmental technology and is earned through achievement as a researcher, designer, educator or engineering executive. The Society elevated 13 members to the grade of Fellow ASHRAE, and one of them was our very own Director, Mark Modera.

 

Dr. Modera’s contributions to ASHRAE have spanned over 25 years, during which time he chaired and served upon many Technical, Standards and Society-level committees, including serving as Chairman of ASHRAE Standards Project Committee 152P, which published a new standard for rating the efficiency of residential thermal distribution systems in 2004.

 

“I am honored to be recognized by ASHRAE as a fellow. I plan to continue my work in HVAC research and technology development in support of ASHRAE, through my efforts at the Western Cooling Efficiency Center and as a Professor of Mechanical Engineering and Environmental Engineering at UC Davis. Related to my work that ASHRAE recognized, the WCEC is currently testing the use of aerosol particles as a method for sealing building envelopes. We have recently achieved proof of concept n the laboratory, and performed a successful test in a new home. We are hopeful that this technology will prove successful in solving energy waste from leaks in building envelopes.”