Energy Efficient HVAC Packages for Existing Residential Buildings
Diagram of one of the technology packages used for this research
This project will demonstrate and evaluate two residential retrofit packages that use advanced technologies to improve single-family building envelopes, indoor air quality, and cooling efficiency. Package 1 includes a sub-wetbulb evaporative chiller (SWEC) with distributed fan coils, combined with a Smart Residential Ventilation system and extra-tight envelope/ducts obtained with a new aerosol sealing technology. Package 2 includes the same sub-wetbulb evaporative chiller connected to a central-system fan coil, combined with a NightBreeze whole-house ventilation/pre-cooling system and extra-tight aerosol-sealed envelope/ducts.
Currently, WCEC has identified two residential sites for this project in Davis, CA. We will begin monitoring baseline data on the homes' performance this summer, and will install the retrofits in Summer of 2018. WCEC will collect one year of data for both baseline and post-retrofit periods to evaluate their performance.
Low Cost Geothermal Heat Pumps
This project seeks to validate less expensive methods of building the ground heat exchangers (GHEs) that are a key component of ground source heat pumps (GSHPs).
Currently, WCEC is collecting data on three different shallow-bore helical GSHP installations: two in Davis and one in Vacaville. The data collected will be used to validate a model of this technology that describes the thermal interaction between the GHE and the surrounding soil. Ultimately, the model will be integrated into EnergyPlus energy modeling software to simulate the performance of a GSHP that utilizes this new heat exchanger design.
Field Test for an Evaporatively-Cooled Condensing Unit
Diagram of the water-cooled condenser added to a traditional rooftop unit
WCEC field tested a water-cooled condenser unit retrofitted onto two existing package rooftop units (RTUs) in Simi Valley, CA. This project characterized the overall system performance and energy efficiency over a two-year span before and after the water-cooled condenser coil was added.
WCEC has drafted the final report for this field study, and the results will be published soon to the Emerging Technologies Coordination Council’s website here: Emerging Technologies Coordination Council Reports
The results showed that the new condenser reduced total cooling energy use over the summer by 12% and peak energy demand by 25% on the hottest days.