Energy performance of the economizer cycle under three climatic conditions in Saudi Arabia

Heating, ventilating and air conditioning (HVAC) systems are the main consumer of energy in buildings. A considerable amount of energy can be saved if the HVAC system is properly designed, operated and controlled. In all-air HVAC systems using an economizer cycle (which allows the use of outdoor air to condition interior spaces when it is at an appropriate temperature) can result in considerable energy savings. This study investigates the potential for energy savings when the economizer cycle is employed under three climatic conditions in Saudi Arabia: hot-humid summer and mild winter; moderate summer and winter; and, hot-dry summer and cold winter. The Building Energy Systems Analysis computer model (BESA) is utilised to model and analyse energy performance of the economizer cycle in a typical office building exposed to these three different climatic conditions. Simulation results indicate that the greatest energy saving by an economizer cycle is achieved in the hot-dry summer and cold winter climate with about 13% reduction in cooling energy requirement. The least energy saving (about 3%) corresponds to the hot-humid summer and mild winter climate. Results from this study are expected to be useful to HVAC designers and operators seeking energy efficiency in buildings through the economizer cycle.