Heat Pump Experiments with Nonazeotropic Mixtures Preporatory Work
Rapport, 1990

The interest of nonazeotropic mixtures as working fluids in heat pumps has increased in the last years. This is due to the harmfulness of CFC fluids for the ozone layer and that nonazeotropic mixtures have been found as an alternative to the use of CFCs. A project has been started consisting of making an experimental study of an onefamily- house heat pump working with nonazeotropic mixtures of HCFC22 and HCFCI42b. The first part of the project is to instrument the heat pump and to make the measuring equipment work properly before starting further experiments. This includes three steps in the development of the work. Calibration of the measuring equipment (thermocouples, pressure transducers, flowmeter), writing of a measuring program check that all instrumentation is done in a correct way and works well. Test runs of the heat pump have been done with HCFC22 as refrigerant in order to check the measuring equipment. The results showed a misfit of the heat balance and after verifications, it occurred that the problem was due to an incorrectly placed thermocouple. Since the misfit was too high to be only due to heat losses, more tests run have been undertaken to find the sources of errors. In order to get accurate results, the valve on the radiator water side should be changed, a new temperature regulator of the brine should be installed and the condenser should be isolated. The first part is completed and before starting the experiments with nonazeotropic mixtures, some work is still required. The electronic expansion valve should be placed in the system and a regulating program to control it should be written.


Heat pump application

nonazeotropic mixtures



Lydie Buquet

Institutionen för värmeteknik och maskinlära