EXPERIMENTAL STUDY AND PREDICTIVE ANALYSES OF A LARGE SCALE FLAT PLATE SOLAR COLLECTOR WITH CONTINUOUS SERPENTINE TUBING CONFIGURATION AND BUILDING ENVELOPE INTEGRATION
Authors: Khan, Z. and Wen, Z.
Start date: 2 July 2017
The majority of commercially available solar heat collectors are installed on rooftops as frame-mounted or frame-supported installations without fully utilising the roof area. This also leads to an intrusion into the building aesthetics. Integrating solar heat collector into building envelope is a cost effective approach to create energy-generating buildings and at the same time maintaining their architectural value. In this paper, an experimental study of a large scale flat plate solar collector (LSFPSC) with serpentine tubing was conducted that utilised metal roof sheets as absorber either with or without glazing to assess its steady state performance. Continuous serpentine tubing underneath the absorber eliminates the presence of welded and fitted joints that are prone to leaks, corrosion and consequently enhances the system reliability and longevity.
Materials and production costs of LSFPSC are much cheaper (£27.14/m2 and £43.46/m2 for unglazed and glazed configurations respectively) than commercial flat plate collectors (typically > £200/m2 for glazed collectors).
Mean collector efficiencies of 45.36% and 50.20% were observed for the unglazed and glazed configurations of the LSFPSC during the experimental simulations. The experimental results were employed to validate predictive models for studying the effects of key conditional parameters including specific mass flow rate, wind speed and aperture areas with respects to the length and number of serpentine tubing segments.
Five locations across a range of latitudes with diversified solar irradiances, wind speed and ambient temperatures were selected for estimating the monthly and yearly performance of the LSFPSC. These five locations are: Kisangani, New Delhi, Madrid, London and Bechar. The estimation results showed that the glazed LSFPSC is capable of producing good performance in all five locations while the unglazed configuration is heavily dependent on seasonal variations Optimal system dimensions based on serpentine tubing segments were identified as 5 x 2m for glazed and 10 x 2m for unglazed, to fully utilise roofing areas for multiple installations. Both the experimental and predictive simulation results showed great potential of the LSFPSC as an economical renewable energy solution that can be integrated into residential, commercial and industrial building envelopes for a wide range of applications across various regions around the world.