Optimisation and Parametric Study of Heat Transfer in Transpired Solar Collectors Using Computational Fluid Dynamics

Transpired Solar Collectors (TSCs) are building-integrated air-heating systems that are able to fully or partially meet the heating demands of buildings. They convert solar radiation into warm air that can either be used for ventilation, or to heat thermal storage media. TSCs are becoming an increasingly viable alternative to conventional fossil fuel-based heating systems or, more commonly, can be used in a way that is complementary to these systems such that reliance on fossil fuels is reduced. As a consequence TSCs have a potentially important role in meeting future carbon reduction goals. This research has produced a comprehensive numerical model for TSCs based on Computational Fluid Dynamics (CFD) analyses. The model allows parametric studies of key variables and is differentiated from previous models in that it takes full account of factors such as: wind speed and direction, non-uniform flow, turbulent flow, solar radiation intensity, sun position and flow suction rates. It comprises a full size section of cassette-panel TSC that can be easily morphed to reflect a wide range of geometries. A multi-block meshing approach has been employed to reduce grid size and to also resolve jet flows and boundary layers taking place in the plenum and around the absorber plate. Accuracy of the CFD model has been validated against experimental data. An optimisation study has been carried out based on the CFD model to derive the optimal design of the absorber plate. The study has benefited from Design of Experiments (DoE) which is an efficient and non-biased strategy for such analysis. Modeling demonstrated that factors such as wind angle have unexpectedly significant adverse effects on system thermal performance. The studies also furthered understanding of key performance attributes including the effects of suction ratio in terms of optimising performance, and the relationship between sun angle and system operating temperature (important for effective operation of heat storage systems). The optimisation analysis of the absorber plate geometry showed that an optimal combination perforations diameter and pitch together with plate thickness can increase the performance of current TSCs up to 48%. Consideration of these factors is essential if the future performance of TSCs is to be optimised and the technology developed to its fullest potential. This study has provided a basis for optimising the performance of TSCs, developing commercial products, and designing systems based on commercial products in relation to local conditions.

Grantor dc:publisher

Oxford Brookes University

Year dc:date

2018

Author dc:creator

• Tajdaran, Seyyed Sadjad

Contributors dc:contributor

• Ogden, Ray
• Bonatesta, Fabrizio
• Kendrick, Christopher

Statement dc:rights

• All rights reserved

Language dc:language

en

DOI dc:identifier

https://doi.org/10.24384/m6e3-me67

OAI identifier oai:identifier

tle:14499db7-b764-42b3-8fb6-af30afd91462:d6bd9758-527a-46cd-bfe2-c433766e8fca:1