Water Roof Sky Cooling

The cold water is stored for use during the day by direct conduction to the roof whitecap r fan coils whitecap t or coils entrenched in the floor slab whitecap f.

Water roof sky cooling. Traditional building surfaces such as paint coatings brick and concrete have high emittances of up to 0 96. The second cooling system consists of a green roof with pipes embedded in it and cooled with irrigation. Radiative cooling thus offers potential for passive cooling for residential and commercial buildings. Riffat experimental investigation of a building integrated photovoltaic thermal roof collector combined with a liquid desiccant enhanced indirect evaporative cooling system j.

A cool roof is a roof designed to maintain a lower surface temperature in bright sunshine than a traditional roof source. How to beat the heat for top floor owners. 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. Excess water that is not absorbed is recollected and reused.

The system works by spraying water from a water tank over the roof at night where it cools by radiation and evaporation. Consequently they radiate heat into the sky to passively cool buildings at night. Using a 10 00 per kw demand charge on a 100 ratchet. Yes water on the roof will help cool it.

Down to earth 277 501 views. While the term cool roof is sometimes used to describe any roofing surface that is cooler than a standard rooftop green certification. If you spread 1 gallon of water on the roof once an hour and it evaporates you. 77 tons uses 100 1 kw based on 1 3 kw per ton.

1 gallon of water consumes 8000 btu as it evaporates. A surface facing the sky will eventually eject some of its heat and that rejection takes the form of thermal radiation. The pipes absorb heat from the cells and then dissipate it through the green roof. References mahmut sami buker blaise mempouo saffa b.

Radiative sky cooling occurs wherever there s a ground and a sky. Both experiments demonstrate the potential for water based cooling combined with green roofs. Energy savings for this example illustrate the benefit of roof cooling in relieving the energy crisis. Department of energy the surface of a cool roof reflects more sunlight and releases more heat than a so called hot or dark roof.

The whitecap system employs the cooling of water by night sky radiation convection and evaporation of water in an open water cycle. He is working on a simple and inexpensive and very energy efficient space cooling system that uses water cooled via radiation to the night sky.