Energy Interactions of Electric Clothes Dryers and Heat Pump Water Heaters with Building Equipment Systems

The way in which an appliance is used or where the appliance is located affects its energy usage. The building equipment system which usually is most affected by the efficiency and/or the manner of operation of other building equipment systems (appliances) is the house heating and cooling (HVAC) system. Two cases of energy interactions between appliances and the house HVAC are discussed, and measured operating data are used to calculate the appliance energy usage including the HVAC interaction. The first study involves the interaction between a heat pump water heater (HPWH) and the house HVAC. Since an HIPWH extracts energy from the air in its surroundings and adds it to the water it is heating, the load on the house HVAC will be changed if the HPWH is located in a conditioned space. The second study concerns the increased amount of infiltration air brought into a house caused by venting a clothes dryer to the outside. All the increased infiltration air must be conditioned by the house HVAC if the dryer is located in a conditioned space. Graphs and tables based on measured data are presented which show the estimated interaction of the house HVAC with an HPWH and a vented electric clothes dryer.