Energy performance comparison of heating and air-conditioning systems for multi-family residential buildings

The type of HVAC system has a large impact on the heating and cooling energy consumption in multi-family residential buildings. This article compares the energy performance of three HVAC systems: a direct expansion split system, a split air-source heat pump system, and a closed-loop water-source heat pump system with a boiler and an evaporative fluid cooler as the central heating and cooling source. All three systems use a gas furnace for heating or heating backup. With the aid of the detailed energy simulation program, EnergyPlus, comparisons are made in a number of scenarios, including different climate conditions, system operation schemes, and applicable building codes. It is found that with minimum code-compliant equipment efficiency, the air-source heat pump performs the best among all simulated scenarios except in extremely cold climates. The water-source heat pump tends to perform better than the split direct expansion system in cold climates but is worse in hot climates.