Study on adsorption and thermoelectric cooling systems using Boltzmann transport equation approach

Abstract

In this chapter, the Boltzmann Transport Equations (BTE) is used to formulate the transport laws for equilibrium and irreversible thermodynamics and these BTE equations are suitable for analyzing system performance that are associated with systems ranging from macro to micro dimensions. In this regard, particular attention is paid to analyze the energetic processes in adsorption phenomena as well as in semiconductors from the view point of irreversible thermodynamics. The continuity equations for (i) gaseous flow at adsorption surface, and (ii) electrons, holes and phonons movements in the semiconductor structures are studied. The energy and entropy balances equations of (i) the adsorption system for macro cooling, and (ii) the thermoelectric device for micro cooling are derived that lead to expressions for entropy generation and system's bottlenecks. The BTE equation is applied to model the adsorption cooling processes for single-stage, multi-stage and multi-bed systems, and the simulated results are compared with experimental data. This chapter also presents a thermodynamic framework for the estimation of the minimum driving heat source temperature of an advanced adsorption cooling device from the rigor of Boltzmann distribution function. From this thermodynamic analysis, an interesting and useful finding has been established that it is possible to develop an adsorption cooling device as a green and sustainable technology that operates with a driving heat source temperature of near ambient. Moreover, the Onsager relations are applied to model the thermoelectric transport equations and, after coupling with Gibbs law and BTE, the temperature-entropy flux derivations are further developed and presented the energetic performances of thermoelectric cooling systems. © 2010 Nova Science Publishers, Inc.