| 摘要 |
<p>A normally smooth metal surface in a solar energy absorber which reflects sun heat undesirably, even under a black coating given. is mechanically roughened. This may be done by sandblasting, or by brushing or friction with coarse granular material, before the black coating was applied. An additional advantage of roughening the surface is that the black coating adheres better, and survives possible bending when the sheet is being erected. The invention applied equally to flat surfaces and to those textured with ribs, hollows, etc.</p> |
