Development of a high-temperature Heat Pump in the KETEC research project [29]

Currently, a high-temperature Heat Pump for temperatures up to 140 °C in the range of 250 kW heating capacity is being developed at the ILK Dresden as part of the KETEC project (Research Platform for Refrigeration and Energy Technology) funded by the German Federal Ministry of Education and Research and the Free State of Saxony.

The starting point for these developments was an experimental sample in the smaller power range of approx. 15 kW heating capacity, which was developed, built and tested at the ILK in the years 2015-2017. The main objective is to provide useful heat at a temperature level of up to approx. 140 °C by utilising waste heat sources in the range of 70 to 90 °C. Challenges in the development are the stability of the refrigerant, the suitability of compressors, heat exchangers and injection valves as well as the selection of a suitable refrigerating machine oil, especially for the targeted high temperatures.

In particular, separate investigations were carried out on refrigerant compressors in advance (determination of characteristic envelope, start-up behaviour, special features). Special experiences with the compressor in connection with high temperatures, the different viscosities of the oil and the electrical integration were not previously available and are presented. These will be an essential part of the presentation.

Further analyses of individual components and an insight into the overall project (Presentation of P&I schematic, 3D design and further details) round off the presentation.