Overview

 

Around 80% of individual systems in California are RTUs, and around half of all commercial floor space in the United States is cooled by RTUs.

 

Rooftop air conditioning units (RTUs) are self contained units that are typically installed on the roof but may be installed at ground level. Around 80% of individual systems in California are RTUs, and around half of all commercial floor space in the United States is cooled by RTUs. Most of these systems are older RTU models that are not as efficient as the models being made today. Installation of new RTUs is costly, which can discourage building owners from upgrading.

 

A cheaper solution to this problem is to retrofit the RTU. Not only is it appealing to retrofit older units, it can also be worthwhile to retrofit new RTUs with advanced control strategies. Some of the individual technologies that can be implemented in these retrofits include variable frequency drives (VFDs), advancedeconomizer controls, and demand control ventilation (DCV). In our research we want to answer the following questions:

 

  • With the integration of these new technologies in retrofitting packages, which combination of these technologies will be optimal for different applications?
  • What is the potential energy and money savings for these retrofitting options?
  • How do real world scenarios affect the efficiency of these technologies and what are the implications?

 

In answering these questions, applying these retrofits can be easier for the consumer and can lead to these specific technologies being rebated by utility companies if installed. Many of these technologies are already being installed with promising results.