Exergoeconomic optimisation of an air-conditioning rotary regenerator: effect of matrix thermal conductivity on its performance

Abstract

The purpose of this paper is to demonstrate the importance of the use of exergoeconomic analysis in the optimisation of the geometry of a rotary regenerator. The optimum geometry of a rotary regenerator is determined using the unit cost of the exergy of the warm air delivered as the objective function. The running cost is determined using different unit costs for the pressure component of exergy, EΔP, and the thermal component of exergy, EΔT, which are evaluated separately. A mathematical model using a finite difference technique of matrix thermal conductivity and heat transfer is presented and the governing differential equations have been formulated in terms of the characteristic dimensionless groups (Πt, Λt and Ζt) and the effect of two different materials is examined. The effect of variation of the regenerator geometry on the objective function is examined and recommendations are made for the selection of the most appropriate parameters for a rotary regenerator. The results show that the effect of thermal conductivity on the minimum exergoeconomic objective function is slightly over 1% for mild steel and 3.374% for aluminium.