CETIAT has accomplished measurements of a combined brine-to-water heat pump using desuper¬hea¬ting of the compressed refrigerant. Fig. 1 depicts the layout of the system. The system has the following operation modes: space heating only and combined space heating and DHW production by desuperheating. In addition, an electrical back-up heater is used, if there is no space heating, during night times and if the maximum temperature of the storage tank is less than 60°C.
The testing of the system has been performed according to existing standards and standards being currently discussed or introduced: The single heating mode according to EN 14511, CEN/TS 14825 for part load operation, EN 255-3 and M/324 with the European reference tapping cycles No.2. In conclusion, a test procedure for these types of heat pump systems is proposed.
                          

Fig. 1: Simultaneous brine-to-water heat pump of French project

EdF has performed tests for part load operation of an air-to-water heat pump in heating and in cooling mode at different load ratios [5% to 100%], different capacities of the distribution/emission system [11, 22, 33 l/kW] and different settings of the hysteresis controller. Delivered results shall serve as hints for the calculation method by providing correction factors for part load operation.. Fig. 2 shows the layout of the test rig for the part load testing.

Fig. 2: Layout of the test-rig for the testing of part-load operation of an air-to-water heat pump