Investigation and Integration of CO2-Ejectors in Heat Pump Systems for Energy Efficient Design of High-Temperature Heat Pumps with High Heating Capacity

• Applicant: Professor Dr.-Ing. Jürgen Köhler
• Subject Area: Technical Thermodynamics
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 263898634

In the project, ejectors used in high-temperature CO2 heat pumps are investigated experimentally and numerically using CFD. The work focuses on two ejectors, one replacing the expansion valve and an oil-ejector used in the oil return. In a high-temperature CO2 heat pump, the high-side pressure level is higher than the one in the previously investigated CO2 refrigeration systems. Thus, new effects such as metastability might occur. Therefore, new experimental investigations of the ejector as well as an extension of the numerical CFD model developed at IfT is needed. The oil-ejector has not been investigated previously, thus extensive new measurements of this novel ejector are needed. Fluid properties of a CO2-oil-mixture, which flows in the oil-ejector, are needed in the numerical CFD model, which describes the fluid properties of the mixture correctly.

• DFG Programme: Research Grants