Green Roof Evaporative Cooling

Methods of evaporative cooling include roof pond systems which can also lose heat by radiation and convection and water spraying.

Green roof evaporative cooling.

A concentration of green roofs in an urban area can even reduce the city s average temperatures during the summer combating the urban heat island. Department of energy the surface of a cool roof reflects more sunlight and releases more heat than a so called hot or dark roof. A cool roof is a roof designed to maintain a lower surface temperature in bright sunshine than a traditional roof source. An evaporative roof cooling system is designed to reduce the temperature of a roof from 165 f to about 90 f.

While the term cool roof is sometimes used to describe any roofing surface that is cooler than a standard rooftop green certification. In the simplest form this involves placing a pond on the building roof. Finally the experimental investigation summarizes the benefits of combining green roofs and evaporative and radiant cooling of a water to air heat exchanger as a solution for building cooling and proposes simple equations to anticipate their temperature cooling effects. This cools the roof which acts as a heat sink and absorbs heat from the.

Motor not included model 4001 sd 571 40 571 40. Studies in rio de janeiro have demonstrated that the underside of green roof systems are significantly cooler up to 12 deg c than plain concrete roofs. This effect creates an effect equivalent of r 7 roof insulation during the day. It should be noted that the minimum underside temperature during night time does not fall as much in a green roof system as the growth medium acts as an insulator 3.

Heat is now transferred out of the building through the roof. As water evaporates from the pond heat is consumed. A green roof reduces cooling by evaporative cooling loads on a building by fifty to ninety percent especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir. Rather than absorbing heat as does.