This paper investigates the parameter dependencies in the design of ground source heat pump systems (GSHPS) for heating and domestic hot water purposes. Based on parameter studies using the system configurator GeoWPSys+Web, the system interrelationships in the design of GSHPS are analyzed with regard to technical, energetic, economic and ecological evaluation parameters. The cost-effectiveness and the ecological evaluation parameters are highly dependent on the building's energy demand and on the seasonal coefficient of performance (SCOP). Economic savings of a GSHPS compared to a gas condensing boiler (GCB) mainly depends on the investment costs as well as on the gas and electricity prices and their annual increases. In addition to economic and technical variation options, GeoWPSys+Web can also map influences on the CO2 emissions of the GSHPS, e.g. by changing the annual CO2 equivalent reduction rate for electricity. In this way, a future increased feed-in of renewable electricity into the power grid can be illustrated.
