Conference article

In this study we analyze the primary energy implications of ventilation heat recovery (VHR) in residential buildings; considering the entire energy chains. We calculate the operation primary energy use of a case-study apartment building built to conventional and passive house standard; both with and without VHR; and heated with electric resistance heating; bedrock heat pump or district heating. VHR increases the electrical energy used for ventilation and reduces the heat energy used for space heating. The primary energy savings of VHR are greater for the passive building than for the conventional building. Significantly more primary energy is saved when VHR is used in resistance heated buildings than in district heated buildings. For district heated buildings the primary energy savings are small. VHR systems can give substantial final energy reduction; but the primary energy benefit depends strongly on the type of heat supply system; and also on the amount of electricity used for VHR and the airtightness of buildings. This study shows the importance of considering the interactions between heat supply systems; VHR systems; building thermal properties and its airtightness to reduce primary energy use in buildings.

Mechanical ventilation; Heat recovery; Heat supply systems; Electric resistance heating; Heat pumps; District heating; CHP plant; Primary energy