Air source integrated heat pump simulation model for EnergyPlus

Air source integrated heat pump (ASIHP) is an air source, multi-functional space-conditioning unit with water heating function (WH), which can lead to significant energy savings by recovering condensing waste heat in the cooling season and providing dedicated or desuperheating heat pump water heating in the remaining months. This paper summarizes development of the EnergyPlus ASIHP model. It introduces the physics, sub-models, working modes, and control logic. Based on the model, building energy simulations were conducted to demonstrate greater than 50% annual energy savings, in comparison to a baseline heat pump with electric water heater, over 10 US cities, using the EnergyPlus quick-service restaurant template building. We assessed water heating energy saving potentials using ASIHP versus gas heating, and identified the climate zones where ASIHPs are promising. In addition, a grid integration strategy was investigated to reveal further energy saving and electricity cost reduction potentials, via increasing the water heating set-point temperature during off-peak hours and using larger water tanks.