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

本项目对高温CO2热泵用喷射器进行了实验研究和CFD数值模拟。工作的重点是两个喷射器，一个取代膨胀阀和回油使用的喷油器。在高温CO2热泵中，高压侧压力水平高于先前研究的CO2制冷系统中的压力水平。因此，可能会出现新的效应，如亚稳态。因此，新的喷射器的实验研究以及在IfT开发的数值计算流体动力学模型的扩展是必要的。喷油器以前没有进行过研究，因此需要对这种新型喷射器进行广泛的新测量。CFD数值模型中需要考虑CO2-油混合物在喷油器中流动的流体特性，以正确描述其流体特性。

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.