High-Temperature Heat Pump Test Bench with n-Butane (R-600) Generating Steam

The demand for process heat significantly contributes to energy consumption, and due to the typically fossil-based heat generation, it has a substantial contribution to Germany's greenhouse gas emissions. In order to decarbonize this sector, heat pumps generating process heat, particularly steam, are essential. This work presents a heat pump test bench using the natural refrigerant n-butane (R-600). The heat pump can provide temperatures of up to 120 °C, with capacities reaching up to 125 kWth depending on the source temperature. The results are in line with those from other test benches regarding the coefficient of performance (COP). Further, the operation in three different modes is tested and evaluated: pressurized water heating (PWH), wet steam generation (WSG), and dry steam generation (DSG). The heat transfer shows a slight increase when producing steam.