Methods For Reducing Heat Losses From Flat Plate Solar Collectors - Phase 2 - Final Report PDF Download

Author: University of Waterloo. Research Institute
Publisher:
ISBN:
Category :
Languages : en
Pages : 75

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Author:
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Category :
Languages : en
Pages :

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Improvements to flat plate solar collectors for heating and cooling of buildings are being investigated through two parallel studies. The first study, which deals with the free convective heat loss from V-corrugated absorber plate to a plane glass cover, has shown that, for the same average spacing, the free convective heat loss is greater for a V-corrugated absorber plate than for a plane absorber plate. However, provided the average spacing is large enough, the amount of increase is slight. The second study, which deals with the free convective heat loss in a honeycomb solar collector in which the honeycomb consists of a set of horizontal partitions, or slits, has shown that provided the solar collector is tilted to near vertical, such a honeycomb gives better free convective loss suppression than does a square-celled honeycomb having the same amount of material.

Author: K. G. T. Hollands
Publisher:
ISBN:
Category : Solar energy
Languages : en
Pages : 40

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Author: K. G. T. Hollands
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 80

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Author:
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Category : Solar collectors
Languages : en
Pages : 76

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Author:
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Category :
Languages : en
Pages :

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The present study extends earlier studies by examining the effect of the emissivities of both the absorber plate and the glass cover on the honeycomb's ability to suppress free convection, and on the radiative and conductive heat transfer which takes place across the honeycomb in the absence of free convection. By means of heat transfer measurements on ten Mylar honeycombs, this study has shown that the effect of the above emissivities on the suppression of convection by the honeycomb is slight, and can probably be ignored. On the other hand, the measurements also showed that the effect of these emissivities on the non-convective heat transfer is substantial, but not nearly so large as would have been predicted by existing theories. To explain this latter result theories were developed which take into account the important coupling (ignored by previous theories) between the conductive and radiative modes of heat transfer. These new theories predict the measured heat transfer rates to with about +-15%, depending on the emissivities. The results of this study have direct application to evaluating solar collectors which combine a selective surface with a honeycomb.

Author: University of Waterloo. Research Institute
Publisher:
ISBN:
Category :
Languages : en
Pages : 200

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Book Description

Author: K. G. T. Hollands
Publisher:
ISBN:
Category : Solar collectors
Languages : en
Pages : 40

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Book Description

Author: University of Waterloo. Research Institute
Publisher:
ISBN:
Category :
Languages : en
Pages : 35

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Book Description

Author: K. G. T. Hollands
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 78

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Book Description
Improvements to flat plate solar collectors for heating and cooling of buildings were investigated through two parallel studies. The first study, which deals with the free convective heat loss from V-corrugated absorber plate to a plane glass cover, has shown that, for the same average spacing, the free convective heat loss is greater for a V-corrugated absorber plate than for a plane absorber plate. However, provided the average spacing is large enough, the amount of increase is slight. The second study, which deals with the free convective heat loss in a honeycomb solar collector in which the honeycomb consists of a set of horizontal partitions, or slits, has shown that provided the solar collector is tilted to near vertical, such a honeycomb gives equivalent or superior free convective loss suppression than does a square-celled honeycomb having the same amount of material. Correlation equations for the free convective heat loss are given for both studies.