An experimental and numerical study on heat and mass transfer in adsorbent bed of an adsorption heat pump

Abstract

Because of the limited conventional energy sources, the improvement of thermal heat pumps has gained attentions of researchers in recent years. Adsorption heat pump, which is a kind of thermal heat pump, can be directly operated with the low temperature heat sources such as waste heat, geothermal and solar energy. Although, adsorption heat pump has many advantages compared to the conventional heat pump, there are still many difficulties for its practical application. Adsorbent bed is one the most important component of adsorption heat pump. Heat and mass transfer in the adsorbent bed should be accelerated in order to attain a small sized, high powered adsorption heat pump. In this thesis, a theoretical and experimental study is performed on heat and mass transfer in an adsorbent bed. A detailed literature survey on the design of adsorbent bed is done. The designed adsorbent beds are classified, and their advantages and disadvantages are discussed. In order to analyze heat and mass transfer in an adsorbent bed, transport of adsorptive in an adsorbent particle should be well known. A theoretical study on heat and mass transfer in a single adsorbent particle located in an infinite adsorptive medium is performed to understand the effects of internal and external heat and mass transfer resistances. Heat and mass transfer equations for an annular adsorbent bed are derived for uniform and non-uniform pressure approaches and numerically solved to determine temperature and concentration profiles in the bed. These equations are also non-dimensionalized to reduce number of governing parameters. The non-dimensionalization of the equations yields important dimensionless parameters that can be used not only to describe heat and mass transfer in an adsorbent bed but also employ them during design of the bed. Furthermore, an experimental setup was designed and constructed to validate the obtained numerical results. The experimental results were compared with the solution of the numerical results and a good agreement was obtained between them.