Effect of selective surface degradation on the performance of solar water heating systems
| Autor: | A.P. Brunger, K.G.T. Hollands, A. Karagiozis, G. Brouwer |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Solar System
Materials science Field (physics) Renewable Energy Sustainability and the Environment business.industry Selective surface Surfaces Coatings and Films Electronic Optical and Magnetic Materials Computational physics Optics Service life Range (statistics) Degradation (geology) Solar water heating Thermal emittance business |
| Zdroj: | Solar Energy Materials and Solar Cells. 25:125-141 |
| ISSN: | 0927-0248 |
| DOI: | 10.1016/0927-0248(92)90022-h |
| Popis: | Selective surface often degrade in the field. Their solar absorptivity αs and thermal emittance ϵ change with time in service by some amount, say Δαs and Δϵ, from their starting values. It is important to quantify the effect this degradation has on the annual fraction solar Fs. A given relative change in Fs can be caused by different combinations of Δαs, and Δϵ. In this paper we use computer simulation of solar domestic hot water systems to graph these combinations, in a plot of Δαs versus Δϵ, for relative changes in Fs, of 10% and 5%. The slope and intercepts of this plot, which is found to be linear, are studied for their dependence on a wide range of solar system parameters, such as geographical location, collector area, and set point temperature. We find that the slope, and - for starting values of Fs less than about 0.5 - the intercepts, are relatively insensitive to the system parameters. We show that this result is consistent with a simple model. For Fs ⩾ 0.5, the intercepts rise sharply with Fs, in a way that is strongly (and to some extent, only) dependent on the geographical latitude of location. These results have direct application to projecting the useful service life of a selective surface. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|