The Potential of Air-Water Heat Pumps in a Belgian Residential Retrofit Context in relation to Future Electricity Prices

Retrofitting plays an important role in reducing space heating energy demand in the Belgian residential building stock. Moreover, retrofitted buildings allow the application of low temperature heat emission systems combined with heat pumps. In this context, the potential of air-water heat pumps is assessed from an energetic and economic point of view, by considering multiple combinations of building retrofit options, heating system components and energy prices, resulting in different scenarios. Each scenario leads to a different space heating demand while domestic hot water demand is equal in all cases. Results of dynamic simulations in Modelica show that retrofitting the building envelope is always beneficial from an energetic point of view, but the economic viability strongly depends on the age of the dwelling and energy prices. Regarding the heating system, a single stage heat pump combined with a low temperature heat emission system, amongst which the recuperated original radiators are also taken into account, leads to the lowest energy use. A gas condensing boiler is still the most cost effective solution with current prices in Belgium, but the ratio between mean electricity price and gas price appears to be one of the most important drivers for the competitiveness of heat pumps.status: publishe