18 May 2017

P.1.7.4 Evaluation of Solar Heat Pump for Residential Applications in the Midwest U.S.

More than 40% of the energy consumed in the U.S. is used in buildings and almost half of that amount is used for heating or cooling. Current HVAC technologies allow for efficient thermal management, but most utilize energy harvested from fossil fuels or convert electricity directly into thermal energy. Alternative heating technologies such as heat pumps and solar thermal collectors can reduce the energy used for heating.
To showcase these sustainable technologies, a teaching laboratory at a university integrated a residential heat pump water heater with an existing solar thermal system. Solar is the primary source of heat and the heat pump is used as a back-up for when the sun is not available. A primary/secondary pumping system allows multiple modes of operation, including hot water, hydronic heating, and reheat for a small commercial air handling unit.
An energy dashboard that evaluates the heating performance of the Solar Heat Pump System (SHPS) in real time has been created. The primary efficiency metric is the Energy Factor (EF), which is the ratio of useful heat delivered to the electricity used. The EF for the solar heat pump system varies from 1 to greater than 40 depending on the weather. Since the heat pump is located entirely inside the conditioned space an additional benefit/detriment for space cooling is noted based on the season.