Roof Sprinkler System Cooling

Some of the water evaporates which increases the relative humidity while reducing temperatures in the microclimate.

Roof sprinkler system cooling.

When rooftop sprinklers are activated they spray water high up in the air which lands on the roof trees and other surfaces that are within range. This has been attempted thousands of times during wildfires with very limited success. The microclimate is the area right around where the sprinklers are located. This effect creates an effect equivalent of r 7 roof insulation during the day.

An evaporative roof cooling system is designed to reduce the temperature of a roof from 165 f to about 90 f. 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. The water evaporates and cools the surface. Roof sprinklers work by spraying water at predetermined intervals on a roof s surface.

Here is a some information on two roof sprinkler systems. 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. Heat is now transferred out of the building through the roof. One study indicates that water use is around 100 gallons per day per 1000 sqft of roof area.

As the water evaporates it cools the roof and helps to lower the temperature of the roof tiles and the ceiling cavity beneath it. The principle is similar to the way the human body cools itself with perspiration. These systems provide cooling by spraying water on the roof surface. They are simple and appear to be effective but would not be a good choice in areas where water is in short supply.

Yes water on the roof will help cool it. First the concept of sprinklers on the roof is not new. A rooftop sprinkler system ember s guard is adapted to protect homes from falling embers in the case of a wildfire or bushfire. It is also foreseeable that an owner can use the embers sprinkler system to wet the rooftop of houses on a hot day to cool down the house for general irrigation purposes or wet summer fun.

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. This cooling reverses the heat flow through the roof. These types of systems can also be set up to operate automatically either on a timer or connected to an automatic temperature sensor which triggers the system whenever it gets too hot.