Experimental Assessment of a Combined Absorption-Compression Heat Pump with Ammonia-Water Working Fluid for High Temperature Application

The ammonia-water combined absorption-compression heat pump (CACHP), based on the Osenbrück cycle, represents a promising high-temperature heating technology. However, a significant challenge for the CACHP is the high compressor discharge temperature during large temperature lift between source and sink, which severely limits its application potential. To address this issue, an experimental performance evaluation of a CACHP system was conducted under various operating conditions using a liquid injection screw compressor. The goal was to enhance the understanding of system behavior and identify potential improvements for further development and diverse industrial applications. Experiments were conducted and analyzed based on defined performance parameters, such as achieving a sink outlet temperature above 100°C with a heat capacity of 100 kW. The system behavior was subsequently analyzed, and opportunities for further system development were identified. The results are comprehensively presented and discussed, providing valuable insights for future advancements in this technology. (Abstract)