Full Description

Experiments were performed to compare the wind-related heat losses for a flat-plate solar collector which faces away from the wind (leeward orientation) with the losses for a collector which faces into the wind (windward orientation). The measurements were made utilizing a roof-like model situated in a wind tunnel. The results show that the wind heat losses for the leeward orientation are slightly smaller (+/-10%) than those for the windward orientation when the Reynolds number is lower than 60,000. However, for higher Reynolds numbers, the losses are greater for the leeward case. In addition to the heat transfer experiments, a flow visualization study was performed. This study revealed the presence of a pair of counter-rotating eddies situated adjacent to the leeward-facing surface. At higher Reynolds numbers, the vigorous fluid motions within the eddies tend to enhance the heat transfer at the plate surface.

Citation: ASHRAE Transactions, Volume 87, Part 1, Chicago, Illinois