Absorption heat transformers – A comprehensive review

In recent years, the use of absorption heat transformers (AHTs) has reached a remarkable edge. AHTs have great potential in the utilization and upgrading of low-level heat sources. These are typically waste heat obtained from industrial processes and those supplied from solar and geothermal sources. Other benefits of absorption cycles include using significantly less electricity, potentially having less CO2 emission, causing no ozone layer depletion, and using natural refrigerants; and these contribute to increasing the attractiveness of these machines. The use of absorption heat transformers has become even more popular as the cost of fossil fuel continues to rise. In the present work, a comprehensive literature review has been carried out on AHTs, their applications, crystallization risk, working fluids, as well as performance evaluation by applying different models and economic aspects.