German national project

The national project of Germany is dedicated to field monitoring of heat pumps for low energy houses.
A large field test of about 100 heat pumps is conducted in co-operation with 7 heat pump manufacturers and 2 utilities.
The heat pump types in field testing are mainly ground-coupled brine-to-water as well as some outdoor-air-to-water and water-to-water heat pumps. The first part of the field test has been started in 2006 and will continue until 2008. Some systems will continue to be measured until 2010. In summer 2008 further 30 systems will be installed and measured until 2010.
Results shall serve

• to evaluate the actual seasonal performance of the latest generation of heat pump systems incl. the domestic hot water operation
• to derive technical expertise for the further development of heat pumps for well-insulated houses
• to investigate the impact of eventual refrigerant losses of heat pump on the seasonal performance

An example of the measurement points for a brine-to-water heat pump is given in Fig. 1.

Fig.1    Example of online visualisation with measurement points for heat flows, electricity inputs and temperatures

Moreover, another field test of heat pumps in the application of retrofitting of boilers will be accomplished in charge of the German utility E.ON in the years 2006-2009. Heat sources for the retrofit application are brine-to-water and air-to-water heat pumps. The selected houses comprise annual energy needs for space heating in the range of 150-250 kWh/m²/a and requirements for high supply temperatures. Results shall deliver the feasibility of this retrofit option in terms of energy savings, CO2-emission reduction and the economy of the system.