Canada has an important potential of solar radiation, which predicts solar installations throughout the country. In addition, 80% of residential energy used is devoted to the production of domestic hot water and space heating (Sibbitt et al., 2007). This energy could be provided by solar evacuated tube collectors which have better performance than flat plate solar collectors when temperature reaches 70-80 oC because of their high insulation.
The main objective of this work is to study the flow of water in a vacuum tube solar collector open at both ends. The study is done using ANSYS Fluent 14.0 software. The fluid enters from the cold manifold. Then it is divided in different vacuum tubes and being heated by solar radiation to finally quit through the hot manifold. The weakness of this basic model is that it does not offer a balanced distribution of water in the various vacuum tubes.
Before discussing the results predicted for the flow in the solar collector of interest, it is necessary to validate the use of the software by comparing the results obtained with other theoretical results. The results are compared to those obtained by Jones and Lior (1994). A good agreement was found between the results obtained by both methods.
The distribution of water in the solar collector is quantified based on a parameter, Ω, which is a factor that "measures" the degree of uniformity. For the basic geometry (Z-configuration) and for a mass flow equal to 0.10 kg/s, Ω is equal to 99.17 %. Several geometrical parameters, such as the length of the tubes, the diameter ratio, r, and the spacing between the tubes, were varied to investigate their effect on the distribution. Also, the change in the positions of input and output of water showed that the U-shaped configuration provides a more uniform distribution in the solar collector.
Finally, the solution proposed to further improve the flow distribution is to shrink linearly the cold manifold. Thus, the factor Ω increases from 99.17 %, for the basic geometry, to 99.80 %.
| Date | 23 Sept 2015 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Daniel Rousse (Supervisor) & François Morency (Co-supervisor) |
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Boukadida, M. (Author),
Rousse (Supervisor) &
Morency (Co-supervisor),
23 Sept 2015Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering