TY - GEN
T1 - White roof turning green
AU - Lerum, Vidar
PY - 2005
Y1 - 2005
N2 - The thermal performance of a green roof on a single family residence in Norway has been monitored since 2003. A previous paper (1) reported on the dampening effect of the well insulated high mass roof on the heating load during winter conditions. It was also found that the surface temperature at the roof membrane was prevented from going below zero degrees C while the ambient air temperature dipped down to below minus ten degrees C. This effect, which was evident only when the freeze and thaw cycles were shorter than five days, was attributed to the thermal lag represented by the phase change of water into ice. A layer of snow with varying thickness and moisture content represents a dynamic, added R-value to the roof assembly. This second paper from the same research project reports on the analysis of the thermal performance of the green roof during summer conditions. Parallel to the winter performance, a dampening effect of the high mass roof on the roof membrane surface temperatures was detected. This means that the cooling system may be down-sized significantly or eliminated all together. It was also found that a grass roof may deliver additional cooling to the building interior on sunny days preceded by rain. At the actual location in Norway, this phenomenon was detected late in the fall when no cooling was required to condition the interior space. It was assumed that this evaporative cooling effect could represent a significant passive cooling strategy in arid climates, provided that the green roof was irrigated.
AB - The thermal performance of a green roof on a single family residence in Norway has been monitored since 2003. A previous paper (1) reported on the dampening effect of the well insulated high mass roof on the heating load during winter conditions. It was also found that the surface temperature at the roof membrane was prevented from going below zero degrees C while the ambient air temperature dipped down to below minus ten degrees C. This effect, which was evident only when the freeze and thaw cycles were shorter than five days, was attributed to the thermal lag represented by the phase change of water into ice. A layer of snow with varying thickness and moisture content represents a dynamic, added R-value to the roof assembly. This second paper from the same research project reports on the analysis of the thermal performance of the green roof during summer conditions. Parallel to the winter performance, a dampening effect of the high mass roof on the roof membrane surface temperatures was detected. This means that the cooling system may be down-sized significantly or eliminated all together. It was also found that a grass roof may deliver additional cooling to the building interior on sunny days preceded by rain. At the actual location in Norway, this phenomenon was detected late in the fall when no cooling was required to condition the interior space. It was assumed that this evaporative cooling effect could represent a significant passive cooling strategy in arid climates, provided that the green roof was irrigated.
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M3 - Conference contribution
AN - SCOPUS:84870488017
SN - 9781622762637
T3 - Proceedings of the Solar World Congress 2005: Bringing Water to the World, Including Proceedings of 34th ASES Annual Conference and Proceedings of 30th National Passive Solar Conference
SP - 424
EP - 429
BT - Proceedings of the Solar World Congress 2005
T2 - Solar World Congress 2005: Bringing Water to the World, Including 34th ASES Annual Conference and 30th National Passive Solar Conference
Y2 - 6 August 2005 through 12 August 2005
ER -