Roof Thermal Transfer Value

Thermal benefits of green roofs.

Roof thermal transfer value.

The rttv model is very similar to the ottv model except that due to different orientation the model coefficients are different. In this paper a new rttv model is proposed with new formulation for modelling the equivalent thermal resistance increment due to the solar reflectance effect on opaque roofs using the previously developed crht cool roof heat transfer model. Yik and wan 2005 stated that the ottv is an appropriate building envelope energy performance index for use in regulatory control. In a typical meteorology year the modeling results show that the shingle and thermoplastic polyolefin roof transfer 78 9 294 1 kwh m yr and 8 5 128 2 kwh m yr of heat into the.

Plants and substrate require energy and mass balance. In winter the heat loss is simple transmission based on the inside and outside temperature and u value of composite structure. Q winter u a ti to ti inside air temperature. The new formulation is incorporated into the u value estimation of the heat conduction gain component.

Modulate heat flux through the roof by. Roof thermal transfer value rttv 6 roof thermal transfer value rttv 6 1 if the roof of an air conditioned building is provided with skylight the ettv concept is also applicable to its roof. Not a conventional insulation material. Shading insulation thermal mass evapotranspiration et q et combined effect.

Roof thermal transfer value rttv model is prescribed for air conditioned non residential buildings as guidelines for thermal performance of roofs in numerous southeast asia countries. R value thermal resistance is a measure of the ability to resist heat transfer. In order to address the inherent limitations in the existing models this study proposes a novel method to incorporate the effects of surface solar reflectance of the opaque portion of roofs into. To outside air temperature.

U value thermal conductance is a measure of a material or assembly to transfer heat. To differentiate between the walls and the roof the term roof thermal transfer value rttv is used instead. In singapore an rttv roof thermal transfer value model is prescribed for air conditioned non residential buildings as guidelines for thermal performance of roofs. In summer the solar radiation affects the outside surface of wall and roof.

Roof and wall are analyzed in the same way.