23 September 2011

EFFICIENCY OF HEAT PUMP SYSTEMS UNDER REAL OPERATING CONDITIONS


Under the direction of the Fraunhofer ISE, two large field tests of newly installed heat pumps have been investigated during last three years. Nearly 200 of air-water, brinewater
and water-water heat pump systems were examined under real operating conditions in single and multi-family dwellings. Values of volume flows, temperatures, heat quantity and
electricity consumption were collected and sent daily to the Fraunhofer ISE headquarter where they underwent an automatic plausibility check. The results show that the ground source heat pumps are especially promising when it comes to reaching high efficiencies
under real conditions. However, there is still a need for optimization in the integration of the unit in the supply system for the house and for the control strategies of the heat pump. Thus, a poorly integrated heat source or an incorrectly designed heat sink can significantly worsen the SPF of the heat pump.