EVALUATION OF HVAC SYSTEM OPERATIONAL STRATEGIES FOR COMMERCIAL BUILDINGS

The inherent limitation in the performance of building envelope compon ents and heating, ventilating and air conditioning (HVAC) equipment ne cessitates examination of operational strategies for improvements in t he energy-efficient operation of buildings. Because of the ease of ins tallation and increasing capabilities of electronic controllers, opera tional strategies that could be programmed with these controllers are of particular interest. The objectives are concerned with the examinat ion 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), co ndenser water reset (CWR) and chilled water reset (CHWR). The indoor a ir quality requirements are met and the latest applicable energy rates from local utility companies are used for Des Moines, Iowa. The resul ts show that, in general, NP is not an effective strategy in buildings with low thermal mass storage, OSS reduces fan energy, and CWR and CH WR could be effective for chillers with multi-stage unloading characte ristics. The most energy-efficient operational strategies are the comb ination 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 new er-type building. Copyright (C) 1996 Elsevier Science Ltd