Design framework for the development of an efficient heat recovery system in Photovoltaic Modules for the suitability of low-medium temperature applications
- Authors: Maditsi, Koketso
- Date: 2019
- Subjects: Photovoltaic power systems , Heat recovery
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/444961 , uj:38910
- Description: Abstract: Energy regeneration through heat recovery is practically possible for maximizing energy obtained from the sun, by recovering and reusing the heat that is typically lost within energy dependent electrical equipment. Solar thermal systems utilize flat plates or evacuated tube collectors which absorb the heat from the sun. Similarly, Photovoltaic (PV) systems absorb solar irradiation to generate electricity. A combination of both technologies results in Solar Photovoltaic/Thermal (PV/T) systems wherein thermal plates or liquid contained tubes cool PV collectors resulting in increased efficiency. Solar Photovoltaic/Thermal Optimised (PV/TO) is simply a PV/T module with an improved thermal output designed and investigated in this research study. The PV cooling mechanism is important because excessive heat in PV panels generates high resistance, which impedes the performance of the solar cell and in the process, results in lower efficiency. PV/T systems are also known to produce low thermal output which makes them unsuitable for applications already serviced by market-ready solar thermal systems. The study is aimed at developing an efficient and cost effective heat recovery system which has been designed specifically to improve the thermal output without compromising the electrical output of the PV/T module. To achieve this, a survey was conducted to understand the PV/T technology market share compared to other solar technologies. Furthermore, a prototype was developed to investigate the effect of Peltier cooling method on PV cells. Two models (PV/T and PV/TO) were developed using Autodesk Inventor Professional and simulated using Autodesk CFD Simulation. The results from the simulations were then used with support from the mathematical models developed to determine the economic performance study of the two models. The survey results showed that only 11% of the respondents are actively participating in PV/T related matters. The experimental results showed that Peltier cooling improves performance by 1.1% higher than conventional cooling methods. The results from economic performance study showed that PV/TO model can archive over 100% solar fraction for the DHW demand of 800 litres/day using only 4 panels whereas PV/T model for the same demand and panel size archives just under 80% of the solar fraction using 9 panels. The overall results showed that PV/TO model optimise thermal output by over 150% and can compete with market-matured solar thermal technologies. , M.Tech. (Mechanical Engineering)
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Design framework for the development of dual heat recovery system in photo-voltaic powered air conditioning systems
- Authors: Maditsi, Koketso , Laseinde, Opeyeolu
- Date: 2018
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/284252 , uj:30693 , Citation: Maditsi, K. & Laseinde, O. 2018. Design framework for the development of dual heat recovery system in photo-voltaic powered air conditioning systems. 17th International Conference on Sustainable Energy Technologies – SET 2018 21st - 23rd of August 2018, Wuhan, China
- Description: Abstract: Energy regeneration through heat recovery is practically possible for maximizing energy obtained from the sun, by recovering and reusing the heat that is typically lost within energy dependent electrical equipment’s. The study is aimed at developing an efficient and cost effective heat recovery system, which is an improvement to existing variants. Solar thermal systems utilize flat plates or evacuated tube collectors which absorb the heat from the sun. Similarly, Photo-Voltaic (PV) systems absorb solar irradiation to generate electricity. A combination of both technologies results in Solar Photo-Voltaic Thermal (PV/T) systems wherein thermal plates or liquid contained tubes cool PV collectors resulting in increased efficiency. The PV cooling mechanism is important because excessive heat in PV panels generates high resistance, which impedes the performance of the solar cell and in the process, results in lower efficiency. PV/T systems are currently sold at relatively high cost and their availability is limited. The study focuses on the development of a dual heat recovery system for harnessing both the heat build-up on the PV plates and the heat generated from the heat exchanger exhaust outlet of a solar air- conditioning system, by incorporating electro-thermal generators and Peltier devices for the optimization process. The research is sectioned into design, prototype development, and a testing phase. The focus of this paper is to share the design phase of the project. The design highlighted herein is a cost effective and highly efficient PV/T model with a different heat absorption approach in comparison to conventional PV/T systems. The heat recovery system design is complete and is currently undergoing extensive tests to complete the testing and optimization phase.
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