16 September 2011

HEATING AND COOLING WITH HEAT PUMPS IN SWISS RESIDENTIAL BUILDINGS


The energy demand for heating decreases in highly-insulated dwellings. Comfort cooling becomes more important due to higher thermal loads and rising summer thermal comfort demands. Heat pumps can provide space heat and domestic hot water but may also provide cooling. The aim of the project is to support energy efficient solutions of heat pump heating systems with additional space cooling option for residential buildings. Nevertheless, first step should always be reducing heat loads by e.g. shading and night-time ventilation. In a simulation study three heat pump systems have been compared. A brine-to-water borehole heat pump system yields the highest efficiency in all operation modes. Only few additional components are necessary to supply also a comfort cooling. An air-to-water heat pump shows the lowest efficiency but also lowest additional system expenditure. A relatively high efficiency achieved a state of the art multi-split air-to-air heat pump, albeit significantly
below the brine-to-water in passive cooling mode. All systems achieve good thermal comfort. Furthermore, an approach is presented how to integrate passive cooling with borehole heat
exchangers into the seasonal performance calculation of heat pump heating systems. Two field measurements of passive cooling with borehole heat exchanger confirm the simulation results and optimisation potential.