CFD analysis and energy simulation of a gymnasium

A computational fluid dynamics (CFD) program EXACT3 has been applied to investigate the temperature distribution and air movement within an air-conditioned gymnasium with four different, but commonly found, exhaust positions in Hong Kong. In this numerical study, the effects of thermal stratification on the energy performance (in terms of cooling load and electricity consumption) are examined with respect to the HVAC plant oversizing issue. It has been found that significant thermal stratification occurs in the gymnasium. The annual cooling load can be overestimated by 45.4% for the best exhaust position when the effect of thermal stratification is not considered. The corresponding peak cooling load and, hence, chiller plant size, will increase from 59.9 to 77.6 kW. The low energy efficiency of the oversized chiller at part-load operation results in a 7% increase in the annual energy use for the HVAC plant.