18 May 2017

K.1.5.1 10 years of heat pumps monitoring in Germany. Outcomes of several monitoring campaigns. From low-energy houses to un-retrofitted single-family dwellings.

Since 2006, Fraunhofer ISE from Freiburg, Germany has been investigating electric heat pumps in single-family dwellings. Within three projects, nearly 250 air-to-water and brine-to-water heat pumps systems have been investigated under real operating conditions in houses with various energetic standards (from low-energy to un-retrofitted stock buildings with high energy demand). In 2016, another project focusing heat pumps in stock buildings was started.
The main focus of all projects was the examination of the efficiency (SPF – seasonal performance factors) of heat pumps under consideration of various operating conditions. Second goal was to investigate possible optimization of running heat pumps systems and of their installation process.
The collected data and achieved results, based on an extensive number of investigated units and a long-term data acquisition, provide a good picture of the operation of heat pumps in central Europe. For example, the last year’s improvements of the components, in particular in air-to-water heat pumps, correspond with the increase of the average efficiency of newly installed units.
The main results confirm the high potential of heat pumps in term of reaching a high efficiency by correctly planed, installed and operated units. Still, a high spread of efficiency of similar heat pumps installation indicates potential of increasing the average values by avoiding failures.