Effect of location on the predicted performance of a heat-pump water heater

A heat pump water heater (HPWH) extracts energy from the air in the environment. The question arises as to how this energy extraction would affect the house HVAC system if the HPWH were located in a conditioned space of a household. A second question concerns the savings obtained by locating the HPWH in an unconditioned space such as a garage or basement. A computer study of these effects was carried out. Since geography, house construction, type and efficiency of HVAC system, and hot water usage will all affect the effective performance, some of the variables were fixed and some were allowed to vary in the study. The effect of locating the HPWH in the conditioned spaces of houses with a high performance heat pump as well as resistance, gas, and oil heated houses with a high performance electric air conditioner was studied. Bin data for each of 18 US cities were used as input weather data. The monthly inlet supply water temperatures to the water heater f each of the 18 cities are given.