Abstract
Natural convection heat-transfer coefficients have been experimentally determined for trough-type collectors. The effects of Rayleigh number, tilt angle, and ideal concentration ratio on the Nusselt number have been experimentally determined over ranges representative of collector operation. The Rayleigh number range tested was up to 10 7, the tilt angle was varied from 30–90° and ideal concentration ratios of 2, 3, 4 and 5 were tested. The experimental results are supported by finite element solutions to the governing equations. A method of extending the results to truncated trough collectors and CPC collectors is suggested. The convective losses are compared to those for conventional flat plate collectors. The critical Rayleigh number increases with concentration ratio. Nusselt number increases more rapidly at high concentration ratio than at low values. Correlation equations are developed over the range of parameters tested. These results are useful to designers of collectors of this type, and allow estimation of the thermal losses during operation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
