Development of a Flat Plate Solar Collector Design Program

Abstract

Flat-plate solar collectors have potential applications in HVAC system, industrial thermal process, and solar engineering. Flat-plate collectors are the most economical and popular in solar domestic heating water system since they are permanently fixed in positions, have simple construction, and require little maintenance. The design of a solar energy system is generally concerned with obtaining maximum efficiency at minimum cost. The aim of this thesis is to develop a design tool for predicting the performance of a flat-plate solar collector. A very detailed thermal analysis of a flat-plate solar collector was carried out to predict the thermal performance. The analysis is based on the established theory about flat-plate solar collector: the radiation absorption, heat loss from the collector, and temperature distribution on the plate. The calculation of useful energy and top heat loss from the collector is based on the aperture area to make a more accurate prediction of collector performance. The net-radiation method was employed to obtain the radiation component of top heat loss from the general collector cover system. The correlation for natural convection heat transfer between the covers and between the plate and cover was selected with the consideration of the low conductivity of plastics. The semi-gray radiation model was adopted to determine the optical properties of the collector cover and absorber plate. Results comparing the design tool calculations with experiments showed good agreement. The collector tests were performed by Florida Solar Energy Center. The calculations based on the information from test reports yielded an accurate prediction of the thermal performance of flat-plate solar collectors. Based on the analysis, a flat-plate solar collector design program (CoDePro) has been developed. The program is arranged so that detailed information about the collector can be specified with an easy-to-use graphic interface. Compiled versions of CoDePro have been distributed to solar engineers from its development level, and it has been modified according to their suggestions. CoDePro has an ability to evaluate the collector performance with high accuracy and can be used as a design tool for flat-plate solar collectors.