Towards the Development of Compact and High Efficiency Adsorption Heat Pumps

A set of thermal compressors (often referred to as adsorption beds) is employed in an adsorption heat pump (AHP) system to achieve the desired cooling, whereas electricity-driven compressors are used in a conventional vapor compression refrigeration system (VCRS). Although an AHP is much more environmentally friendly than VCRS, its massive size is one of the major hindrances towards its commercial application. The primary reason for this bulkiness is the huge amount of adsorbents that are being used in the adsorption beds. A remedy to this major flaw can be the use of composite adsorbents instead of loosely packed powders. Another colossal issue is the poor efficiency of this system which can be partially resolved by (i) proper selection of adsorbent, adsorbate, binder, thermal conductivity enhancer and optimizing their composition; (ii) applying optimum pressure in the consolidation process; (iii) determining the thermophysical properties of adsorbents to select the most suitable one, and (iv) ensuring efficient operation of the system by optimizing the duration of different recovery schemes. In this chapter, the synthesis technique to prepare silica gel-based high-quality consolidated adsorbents is demonstrated, a comparison of several thermophysical properties of the parent and composite adsorbents is presented, and finally, the system operation is investigated and optimized through simulation studies.