Development of a compact ammonia-water Gas Absorption Heat Pump

Costs and size reduction is crucial to assure a large market penetration of Gas Absorption Heat Pumps (GHP) and the resulting cut in CO2 emissions. Such target has driven this work, focused on the development of a small rated ammonia-water GHP, mainly built of components derived from large series production, whose manufacturers actively collaborate to the project. In particular, all heat exchangers except the desorber are fusion-bonded plate heat exchangers. The outcome is an 8 kW GHP prototype, whose diaphragm pump and generator have been specifically designed to reduce the appliance size to the dimensions of a domestic condensing boiler. We investigated the effectiveness of different configurations of the refrigerant circuit, and the benefits of adapting the flow rate of refrigerant and solution to different operating conditions. We achieved a remarkable Seasonal Gas Utilization Efficiency (SGUE) of 1.58 on a net calorific value basis, according to standard EN 12309-6:2014.