Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Siddiqui, Kamran

2nd Supervisor

Straatman, Anthony

Joint Supervisor

Abstract

With the possibility of a global energy crisis on the horizon, the need for renewable energy processes is more crucial than ever before. Solar energy, specifically solar concentrated collectors can provide a green alternative to fossil fuel consumption, but several factors need to be considered to improve their efficiency and make them viable. The present research is aimed at the development of a novel “Optical Guide” to improve performance of traditional thermal receivers in Parabolic Dish Solar Collectors for use in a domestic solar water heater with PCM latent heat storage integration. Two ray trace programs, SolTrace and Tracer were used to model heat flux distributions developed at the bottom of the optical guide for various altitude angles with results indicating SolTrace to be the most accurate modelling tool for high resolution, reliable flux profiles. Generated flux distributions can be used to model heating mechanisms in the thermal storage unit, once favourable profiles for selected PCMs are determined. Mathematical modelling of the heat exchanger with integrated PCM, conducted under several assumptions to simplify heat transfer mechanisms, will be used to provide the framework for detailed development of the thermal storage system.

Summary for Lay Audience

Decreasing fossil fuel supplies for a potential uprising of global energy demand is a strong driving force to the development of efficient, renewable energy production. Solar concentrated collectors, unlike traditional PV solar cells, are capable of utilizing every wavelength of solar irradiance, allowing for extremely high performance efficiencies for these technologies. A deterrent in the feasibility of concentrated solar collectors is the losses associated when transferring heat collected to usable energy. The research proposes a parabolic dish collector system for use in domestic water heating utilizing a novel concept of reflecting all solar radiation to a thermal storage unit, the 'Optical Guide'. The novel optical guide will use optical physics for determination of component locations and will theoretically be able to transfer heat at higher efficiencies than traditional methodologies. Ray trace programs are used to model the flux that is produced in the optical guide to better understand heating mechanisms that occur in the thermal storage unit. Framework for a highly detailed mathematical model is developed and analyzed through alteration of key operating conditions for the solar water heating system.

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