Evaluation of HVAC system operational strategies for commercial buildings

The inherent limitation in the performance of building envelope components and heating, ventilating and air conditioning (HVAC) equipment necessitates examination of operational strategies for improvements in the energy-efficient operation of buildings. Because of the ease of installation and increasing capabilities of electronic controllers, operational strategies that could be programmed with these controllers are of particular interest. The objectives are concerned with the examination of various operational strategies applied to older- and newer-type commercial office buildings utilizing constant-air-volume-reheat and variable-air-volume-reheat HVAC systems, respectively. The operational strategies are night purge (NP), fan optimum start and stop (OSS), condenser water reset (CWR) and chilled water reset (CHWR). The indoor air quality requirements are met and the latest applicable energy rates from local utility companies are used for Des Moines, Iowa. The results show that, in general, NP is not an effective strategy in buildings with low thermal mass storage, OSS reduces fan energy, and CWR and CHWR could be effective for chillers with multi-stage unloading characteristics. The most energy-efficient operational strategies are the combination of OSS, CWR, and CHWR for the older-type building, and OSS for the newer-type building. Economically, the most effective is the OSS strategy for the older-type building and the CHWR strategy for the newer-type building. Copyright (C) 1996 Elsevier Science Ltd