Planning, design and construction of a multi-purpose high-temperature heat pump test bench for hydrocarbons

In this work the basic steps and considerations for design and construction of a multi-purpose heat pump learning circuit are shown to help and encourage further construction of HTHP with natural refrigerants. The refrigerant choice is motivated by basic thermodynamic considerations leading to Butane as choice. The design of the test bench is characterized by various connection options, such as a simple cycle, internal heat exchange or closed/open economizer with two-stage compression, as the most common configurations out of a market survey. The key components are described with a reciprocating piston compressor as most suitable device. Basic considerations on the necessary safety measures accompanied by a rough estimation of the refrigerant mass. An analytical investigation of the assumed design and configuration is performed in order to get an indication about the expected experimental results. For a temperature lift of 60K the open economizer (oEco) leads to the highest COP at the target condensation temperature of 130°C.