Heating, Ventilation, and Cooling Research

Evaporative Cooling

The Next Step to Evaporative Cooling

technical brief page

The OASys is a 3-ton equivalent evaporative cooler that was developed by the Davis Energy Group with the help of PIER. This system uses both direct and indirect evaporative cooling which produces a greater temperature drop than the conventional evaporative cooling units. The system is a considerable advancement from the conventional units for it is able to use less energy and provides a more comfortable environment for occupants. See the final report.

Night Ventilation

NightBreeze™ Cuts Peak Demand, Keeps Residents Cool

technical brief page

The NightBreeze™ is an innovative solution to high residential cooling loads. By circulating cool night air through a house, heat stored in a buildings thermal mass can be released during the night which then allows it to naturally store heat during the day. This significantly decreases energy consumed as well shifting that energy consumption to lower rate periods (off-peak).

A report has been drafted for recommended modeling rules, potential compliance credits, and preliminary eligibility criteria for residential night ventilation cooling systems, which are proposed to be added to the 2013 Title 24. This could potentially lead to substantial energy and thus cost savings for California residents.

Radiant Heating & Cooling

Radiant Heating & Cooling Made Easy

technical brief page

Radiant heating has well-recognized comfort benefits, but has been hindered by high installation costs and more challenging construction trades coordination issues. This brief summary or technical brief describes a PIER project which developed methods to reduce these barriers. See the final report.

These concepts were developed further at the Western Cooling Efficiency Center at UC Davis, culminating into the introduction of several products for commercial buildings, such as ClimateMat by Viega. Big-box retailers, like Walmart, have tested this system in floor-based radiant cooling systems in California and Nevada, and a Title 24 change has been proposed for 2013 to incorporate modeling for radiant cooling into non-residential compliance software. The radiant cooling systems are expected to save more than 40% of energy compared with all-air cooling.

In Viega's case study on Walmart, it was found that the Climate Mat reduced cooling energy consumption by 50% and required less maintenance than the standard forced air systems.


Variable Air Volume Systems

Static Pressure Reset Strategy Boosts Variable Air Volume (VAV) Systems Efficiency

technical brief page

With the help of PIER, a static pressure reset strategy has been created in order to boost the efficiency of VAV air handlers. While standard VAV's are set to maintain a constant pressure in supply ducts, this control strategy allows for reduced pressure during partial load conditions. Demonstrations have shown that this can decrease fan energy consumption by up to 30%.


Large VAVs (Variable Air Volume), Low Loads and High Performance

technical brief page

In the effort to increase the partial load efficiency of Variable-Air-Volume (VAV) air handling systems, PIER helped to create the Advanced Variable Air Volume System Design Guide. The guide provides design strategies that integrate the various system parts of VAV's in order to maintain high performance during low loads, which is often a failing point of standard VAV air handlers. While the guide is focused on multistory office buildings, it can applied to a wide range of building or system types.


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