Advances in Waste Heat and Renewable Energy Utilization

Abstract

Apart from absorption cooling, absorption heating technologies are also widely used for waste heat recovery and renewable energy utilization. Waste heat recovery in district heating systems covers cogeneration heat recovery and flue gas heat recovery, which can improve the overall energy efficiency by 5–30%. Meanwhile, in industrial processes (drying, evaporation, and distillation), technologies such as closed/open absorption heat pump (AHP/OAHP), closed/open absorption heat transformers (AHT/OAHT) and absorption-compression heat pump (ACHP) are employed with various stages, effects and working fluids, to meet temperature requirements of 50–160 °C. To evaluate the efficiency of absorption heating technologies in the renewable energy field, solar heating performances between a solar air source absorption heating pump (ASAHP) and a conventional solar collector heating, are compared within ASAHP’s applicability domain (based on the temperature and radiation ranges). In addition, different geothermal heat pump systems are introduced for cascade utilization of geothermal energy. The absorption-compression heat pump (ACHP) is selected as a promising candidate, and detailed comparisons of this technology working with various novel NH3/IL working fluids are presented. This chapter also provides many advanced prospective for a more reasonable utilization of waste heat and renewable energy sources.