An Analysis of Unglazed Transpired Solar Collectors Based on Exergetic Performance Criteria

In this paper, an exergetic performance analysis of unglazed transpired collectors (UTC), as well as an exergetic optimization of a typical UTC is performed. A steady-state model is used to calculate heat transfers and pressure drop through the perforated plate and back wall. In order to maximize the exergy efficiency, the optimization procedure is carried out for some important parameters including plate hole diameter and hole pitch. A maximum efficieny of 2.28% is obtained. In spite of all the thermal performance advantages, the exergetic efficiency of the UTC is significantly lower than its energetic efficiency. Other parameters such as incident solar radiation, approach velocity, plate hole diameter and pitch are examined in the parametric study.