Roof Surface Evaporative Cooling

Cool roof coatings are white or special reflective pigments that reflect sunlight.

Roof surface evaporative cooling.

This sets up a temperature gradient between the inside air and outside roof surface resulting in loss of heat from the inside to outside. Evaporative cooling is one of the well known techniques to cool the roof surface resulting in the reduction of thermal load of the building. During a shower or artificial watering the porous construction material of a roof absorbs some water depending on its water holding capacity. Coatings are like very thick paints that can protect the roof surface from ultra violet uv light and chemical damage and some offer water protection and restorative features.

A roof with a clean smooth bright white surface can reflect about 85 of incident sunlight and emit thermal radiation with 90 efficiency. The water evaporates and cools the surface. This surface will be only 9 f warmer than the outside air on a typical summer afternoon. This cooling reverses the heat flow through the roof.

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. They are simple and appear to be effective but would not be a good choice in areas where water is in short supply. One study indicates that water use is around 100 gallons per day per 1000 sqft of roof area. In warm climates evaporative spray roof cooling esrc systems not to be confused with roof ponds.

A better way to cool the roof is to change its color. 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. Motor not included model 5000 sd 684 28 684 28. An evaporative cooling system consists of an intake chamber filter s supply fan direct contact or indirect contact heat exchanger exhaust fan water sprays re circulating water pump and water sump.

Evaporative cooling systems are characterised by low energy use compared with refrigeration cooling. An evaporative roof cooling system is designed to reduce the temperature of a roof from 165 f to about 90 f. The evaporation of water causes cooling of the roof surface. You can usually make a new or existing roof cool by selecting the appropriate surface.

These systems provide cooling by spraying water on the roof surface. Champion cooler 6500 cfm side draft wall roof evaporative cooler for 2300 sq. There are many types of roof systems available but the surface exposed to the sun is the one that determines if a roof is cool or not.