Domestic ventilation heat recovery using heat pumps.

The application of heat pumps to ventilation heat recovery in domestic houses is considered. It is shown that the most effective system is a combination of heat pump and heat recovery unit; a plate heat exchanger is the type commonly used. Such units are now commercially available, and can provide heat at a lower cost per kilowatt hour than the Economy 7 tariff. The performance of several units is presented, and seasonal running costs have been computed for a house equivalent to the Capenhurst low energy house design. A heat pump VHR unit would be incorporated in a full house ventilation system, and could provide up to half of the heat required on a design day. It would be practical to reduce or eliminate the storage heating capacity in the house,and use direct acting heaters to provide flexible, accurate temperature control. Such a heating system would provide good temperature distribution and low running costs. The application of a heat pump VHR unit would therefore seem to be an attractive option in a low energy house. Development work is needed on the details of installation and control.