TY - GEN
T1 - The cooling effect and water use efficiency of urban landscape strategies in a hot dry climate
AU - Shashua-Bar, Limor
AU - Erell, Evyatar
AU - Pearlmutter, David
PY - 2008/1/1
Y1 - 2008/1/1
N2 - This paper describes a climatic analysis of landscape strategies for outdoor cooling in a hot arid region, accounting for the efficiency of water use. Six landscape strategies were studied, using different combinations of trees, lawn, and an overhead shade-mesh. The effects of these treatments were tested in two adjacent courtyards at Sde-Boqer, in the Negev Highlands of southern Israel, during summer (July-August). On average, air temperature in the non-vegetated exposed courtyard reached a maximum of about 34°C in mid-afternoon. Compared to this base case, a configuration with shade trees and grass yielded a daytime temperature depression of up to 2.5°C, while shading the courtyard with a fabric shading mesh, counter-intuitively, caused a relative increase of nearly 1°C. Unshaded grass was found to provide only a small air temperature depression and had the highest water requirement. However when the grass was shaded, either by the trees or by the shade mesh, a synergic effect produced greater cooling as well as a reduction in total water use of over 50%. The "cooling efficiency" of these strategies was calculated as the ratio between the sensible heat removed from the space and the latent heat equivalent of the evaporated water. This measure is proposed as a criterion for evaluating landscape strategies in arid regions, where the water resource is scarce.
AB - This paper describes a climatic analysis of landscape strategies for outdoor cooling in a hot arid region, accounting for the efficiency of water use. Six landscape strategies were studied, using different combinations of trees, lawn, and an overhead shade-mesh. The effects of these treatments were tested in two adjacent courtyards at Sde-Boqer, in the Negev Highlands of southern Israel, during summer (July-August). On average, air temperature in the non-vegetated exposed courtyard reached a maximum of about 34°C in mid-afternoon. Compared to this base case, a configuration with shade trees and grass yielded a daytime temperature depression of up to 2.5°C, while shading the courtyard with a fabric shading mesh, counter-intuitively, caused a relative increase of nearly 1°C. Unshaded grass was found to provide only a small air temperature depression and had the highest water requirement. However when the grass was shaded, either by the trees or by the shade mesh, a synergic effect produced greater cooling as well as a reduction in total water use of over 50%. The "cooling efficiency" of these strategies was calculated as the ratio between the sensible heat removed from the space and the latent heat equivalent of the evaporated water. This measure is proposed as a criterion for evaluating landscape strategies in arid regions, where the water resource is scarce.
KW - Cooling
KW - Efficient water use
KW - Hot arid regions
KW - Landscaping
UR - http://www.scopus.com/inward/record.url?scp=85067728055&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:85067728055
SN - 9781905254347
T3 - PLEA 2008 - Towards Zero Energy Building: 25th PLEA International Conference on Passive and Low Energy Architecture, Conference Proceedings
BT - PLEA 2008 - Towards Zero Energy Building
PB - University College Dublin
T2 - 25th International Conference on Passive and Low Energy Architecture: Towards Zero Energy Building, PLEA 2008
Y2 - 22 October 2008 through 24 October 2008
ER -