Water On The Roof For Cooling

These systems provide cooling by spraying the water evaporates and cools the surface.

Water on the roof for cooling. In the simplest form this involves placing a pond on the building roof. Ambient indoor temperature is approx. Cooling with liquid water running off from a sprinkler is not efficient but evaporative cooling from a small amount of water like a periodic sprinkle is very efficient. There should be 1 square foot of vent for every 300 square feet of floor space.

1 gallon of water consumes 8000 btu as it evaporates. Prototype for a evaporative roof for radiant cooling cherry valley ca usa reconsidering comfort. A more refined method involves insulating the pond during the daytime to prevent solar gain. An evaporating layer of water on the roof approaches a wet bulb temperature of 12 c a typical roof reaches 60 100 c mitigating the albedo effect.

Yes water on the roof will help cool it. One study indicates that water use is around 100 gallons per day per 1000 sqft of roof area. Yes you can spray your roof to help cool it down but that will only cool the shingles for a short time and be a large waste of water. As water evaporates from the pond heat is consumed.

This cools the roof which acts as a heat sink and absorbs heat from the interior of the building. 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. 50 radiant heat from surface radiation and 50 air temperature.