MEASUREMENT RESULTS OF A HYBRID ADSORPTION-COMPRESSION HEAT PUMP BASED ON A ROOTS COMPRESSOR AND SILICA GEL-WATER SORPTION CYCLE

摘要

Thermally driven sorption systems can provide significant energy savings, especially in industrial applications. The driving temperature for operation of such systems limits the operating window and can be a barrier for market-introduction. By adding a work-driven compressor, the heat-driven cycle can be made with waste heat at lower temperatures. In this paper such heat pumps, using both the work potential from waste heat and work from a compressor, will be referred to as hybrid heat pumps. ECN has a long history on sorption heat pump research, including both silica gel-water as well as ammonia-salt sorption systems, and has recently started the development of a hybrid heat pump. The final goal is to develop a hybrid heat pump for upgrading lower (＜100°C) temperature industrial waste heat to above pinch temperatures. This heat pump will likely be based on the adsorption and desorption of ammonia on ammonia-salts and combine the continuous process of the compressor with the batch operated sorption reactors. The compressor for these heat pumps will typically run at a low pressure ratio (＜3), to achieve high energy efficiency, and at relatively high volume-flows (＞1000 m~3/hr). The first tests on a hybrid heat pump are, however, conducted on a silica gel-water system that has been thoroughly tested earlier, in combination with a roots compressor. This paper will present the results of measurements on this hybrid heat pump system.