Heat transfer in a solar radiation absorbing fluid layer flowing over a substrate
Abstract
A simple theoretical model has been developed to predict the temperature distribution in an irradiated liquid or liquid suspension flowing along an opaque substrate. The fluid is irradiated by focussing solar radiation on the layer. In the analysis the absorption and emission of radiation by the fluid and emission and reflection by the substrate are considered. A two-band (semitransparent and opaque) radiation model is employed to assess the feasibility of absorbing solar radiation directly in fluid and using the fluid layer-substrate system as a solar collector. The results obtained show that for given flow and thermal conditions there is an opacity of the fluid which yields an optimum thermal performance (e.g. collection efficiency) of such a system. The results also show that, all conditions and parameters being the same, a fluid in laminar flow will yield better performance than a fluid in turbulent flow.
- Publication:
-
Thermal Storage and Heat Transfer in Solar Energy Systems
- Pub Date:
- 1978
- Bibcode:
- 1978tsht.proc...13K
- Keywords:
-
- Fluid Films;
- Heat Transfer;
- Solar Collectors;
- Solar Energy Absorbers;
- Temperature Distribution;
- Working Fluids;
- Conductive Heat Transfer;
- Energy Conversion Efficiency;
- Laminar Flow;
- Liquid-Vapor Interfaces;
- Opacity;
- Radiative Transfer;
- Substrates;
- Fluid Mechanics and Heat Transfer