Using a chain recooling system on buildings in hot and humid climates

In hot and humid climates, warm outside air with rich moisture content impacts several aspects of building operation. To meet the ventilation requirement while maintaining indoor relative humidity (RH) at the desired level, dehumidification is usually required. This is typically done by cooling the air to 55 °F (12.8 °C). However, if the zone cooling load is low, then inefficient reheat may be necessary to maintain the indoor temperature set-point. To achieve better system efficiency, a new HVAC system concept called the “Chain Recooling System” is proposed. In this paper, it is shown that compared to a conventional Single Duct Variable Air Volume (SDVAV) system, the proposed system has the potential to provide better indoor air quality, eliminate the reheat requirement, and reduce fan energy consumption. To demonstrate the advantages of the proposed system, a building on the Texas A&M University campus in College Station, TX, is selected as a case study. It is projected that the HVAC system related energy consumption would be reduced by 15.2% and the average contaminant level would be reduced by 27% if the SDVAV system were replaced by the CRS without sacrificing comfort in the individual zones.