THERMALLY ACCEPTABLE TEMPERATURE DRIFTS CAN REDUCE THE ENERGY-CONSUMPTION FOR COOLING IN OFFICE BUILDINGS

The energy consumption and cost in large office buildings can be reduced by allowing the indoor environment to deviate from the optimum comfort conditions to situations which are still acceptable by most occupants. One such strategy is to allow the indoor temperature to increase in the afternoon in summer. A computer program was developed to predict the thermal sensation and discomfort under transient conditions, and the detailed computer program BLAST was used to evaluate the indoor air temperature, space cooling load, chilled water consumption and seasonal energy use. This paper presents a comparison performed for a reference office building in Montreal between a conventional design, with constant set-point temperature during the operating hours, and a new design, where the indoor temperature is allowed to increase after 3:00 p.m. The results show a reduction of seasonal consumption for chilled water between 34 and 40%, and a reduction of energy budget for HV AC systems of 11%.