Date of Award

2005

Document Type

Master Thesis

Degree Name

Master of Engineering (Research)

Department

Mechanical & Manufacturing Engineering

Abstract

Flat-plate collectors are the most economical and are popular in solar domestic heating water system since they are usually permanently fixed in position, 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 was to develop a mathematical model, for a forced convection solar heated water system. The solar collector in this study incorporated a honeycombed extruded polycarbonate structure, for both the cover and water channels.

A very detailed thermal analysis of the 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 cover 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. ISO 9806-2 standards are being used to validate the results, for the parametric study in the lab, under steady state conditions.

Based on the analysis, the flat-plate solar collector design program was developed. As well as determining the collector performance, the model also facilitates changes to the collector physical properties such as dimensions of the channels, ambient temperature, flow rate, absorbers, material thermal properties, collector and system design optimisation. The results from the program allowed a full parametric study of different collector design criteria, with this polycarbonate structure. The model has an ability to evaluate the collector performance with high accuracy and can be used as a design tool for flat-plate solar collectors.

Comments

The appendices were removed from the digital copy of this thesis due to copyright.

Access Level

info:eu-repo/semantics/openAccess

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