Also called an evaporative cooling system a roof misting system lowers surface temperatures by spraying an extremely small amount of water across the roof allowing the water to cool the roof as it evaporates.
Roof water cooling system.
While a sunlight absorbing black roof can reach up to 190 f in the summer a reflective roof s temperature can be as much as 60 f lower.
John s nebraska system.
As the water evaporates it cools the roof and helps to lower the temperature of the roof tiles and the ceiling cavity beneath it.
This effect creates an effect equivalent of r 7 roof insulation during the day.
This cooling reverses the heat flow through the roof.
The built in thermostat monitors the roof temperature constantly and activates mist when needed this helps keep your roof temperature normal and saves water as well.
Dark surfaces also contribute to the urban heat island effect.
The water evaporates and cools the surface.
A cool roof reflects the sun s energy reducing rooftop temperatures.
Heat is now transferred out of the building through the roof.
David s north carolina system.
An evaporative roof cooling system is designed to reduce the temperature of a roof from 165 f to about 90 f.
Roof sprinklers work by spraying water at predetermined intervals on a roof s surface.
At its lowest tech a roof misting system can be little more than a garden hose set to the mist setting and aimed across the roof.
They are simple and appear to be effective but would not be a good choice in areas where water is in short supply.
John estimates that his systems saves about 5kwh per day on his cooling bill.
The principle is similar to the way the human body cools itself with perspiration.