Numerical investigation of an ammonia-water absorption-compression high-temperature heat pump for hot water and steam production in food processing

Abstract

To achieve climate neutrality in the food sector, there is an urgent need for eco-friendly steam boilers. The absorption-compression heat pumps (ACHP) using an ammonia-water mixture as working fluid can provide a high heat sink temperature at low discharge pressure levels and with temperature glides in absorption and desorption. The present study aims to investigate the performance of the ACHP for hot water and steam production. The simulation model was established based on an ACHP prototype in a NTNU lab. A case of 150 kW heating capacity was simulated with a high pressure of 23.65 bar and a low pressure of 4 bar. The system COP was 2.85 for a pressurized hot water supply temperature of 105 °C. The system performance at different temperature lifts with different heat source inlet temperatures was investigated. In addition, the effects of rich solution composition and compressor intercooling on the system performance were also analyzed.