24 June 2014
This paper presents a cross-comparison of 16 ground-coupled heat pump systems installed in different non-residential buildings, based on high-quality measurement data
collected with high temporal resolution (typically 60 seconds) over several years of operation. The heat pumps have thermal powers ranging from 7 to 291 kWtherm, six of them can also
provide active cooling (reversible operation). They are integrated into various hydraulic concepts including different ways of free cooling and waste heat recovery.The heat pump
systems of the analyzed buildings reach seasonal performance factors (heat pump with compressor and primary pump) between 2.9 and 6.1 kWhtherm/kWhel in heating mode, 3.5 to 42.1 kWhtherm/kWhel when using free cooling via a heat exchanger and 2.1 to 5.0 kWhtherm/kWhel in active cooling. Crucial design factors are the auxiliary energy demand of the
primary pump as well as the supply temperature for the distribution systems. Good efficiencies can be reached when using heat pumps systems which include free cooling,
waste-heat-recovery and distribution systems which permit supply temperatures near room
temperature (16 to 20 °C in cooling mode, 28 to 33 °C in heating mode).