Mechanical Ventilation and Fabric Thermal Storage

Abstract

Modern UK office buildings have a reputation of being energy profligate, largely due to the fan power require ments of commercial air conditioning. Most architects and HVAC designers only associate low-energy con sumption with natural ventilation. However, the UK elec tricity utilities have peak maximum demands in winter, and buildings need to be designed for year-round low- energy usage. Relatively few monitored studies of the total annual energy implications of natural and mechani cal ventilation strategies operating in conjunction with fabric thermal storage have been published. This paper reviews independently published performance data of low-energy buildings and the impact of the various venti lation and fabric energy storage strategies now avail able. It demonstrates that low-energy mechanical venti lation systems incorporating efficient heat recovery and effective fabric energy storage have higher year-round comfort criteria, and significantly lower prime energy consumption, than natural ventilation strategies. Sup plementary cooling and heating demands and consump tion are shown to be minimal in such buildings for tem perate maritime climates.