Pv green roofs proved to be more beneficial than conventional gravel roofs for both the pv module and the temperature of the roof surface.
Pv on green roof.
Hard standing on traditional roofs including concrete asphalt and metal roofs all radiate heat and substantially increase the ambient temperature by as much as 30c in the case of the chicago.
The pv panels should also increase the diversity of vegetation and therefore also fauna using the green roof.
While as a rule the substructure is mounted in such a way that the solar panels are at a height of 10 to 20 cm green roofs require a distance of at least 35 to 50 cm from the roof.
For every degree above this the pv panel can lose anything up to 0 5 efficiency.
The green roof element provides the ballast to hold the a frames and panels in place.
It is suggested that the panels optimum efficiency is at an ambient air temperature of approximately 25 c.
Certain characteristics of the plants lead to improved pv output and the modules protect the plants from high irradiance rates levels.
In order to minimise any shading from the vegetation and to protect the microclimate on green roofs the pv modules are mounted higher.
This means there is no impact on the waterproofing layer below.
Silicate pv panels work optimally at around 23c and american research including on city hall in chicago has shown that green roofs maintain the ambient air temperature at around 25c.
A green roof makes the installation of a frame panels easier.