Basic Adsorption Heat Exchanger Theory for Performance Prediction of Adsorption Heat Pumps

Adsorption modules are the core components of thermally driven adsorption heat pumps and chillers. Due to the transient nature of the adsorption and desorption processes, usually complicated numerical models are used for prediction of efficiency and heat flow rates. In this research article, we suggest a radically simplified calculation based on splitting up the ad- and desorption half cycle into a transient, strongly non-isothermal switching phase and a quasi-isothermal phase. In the quasi-isothermal phase, the heat flow rates can be calculated with relationship between temperature effectiveness (ϵ) and number of transfer units (NTU). Effective thermal resistances account for the heat and mass transfer processes. The prediction quality of our simple calculation in terms of heat flow rates is within ±20% compared with experimental data of two different sorption modules. The suggested method and its experimental validation lay the foundation of a basic adsorption heat exchanger theory.