Night Sky Roof Water Spray Cooling System

We devised an innovative night cooling system consisting of a metal roof serving as a large area low mass highly conductive radiator see figure 1.

Night sky roof water spray cooling system.

The system works by spraying water from a water tank over the roof at night where it cools by radiation and evaporation. Various exotic night sky radiation cooling concepts have been tested in the past. A cool roof coating can benefit a building and its occupants by decreasing energy bills through the reduction of air conditioning needs. Surface and connected to a water pumping and filtration system.

Water is sprayed over a flat or sloping metal panel roof at night. Consequently they radiate heat into the sky to passively cool buildings at night. Coatings are like very thick paints that can protect the roof surface from ultra violet uv light and chemical damage. This cool fluid is circulated through the building to absorb heat and then back to the panels to be cooled.

The next day the cooled water is used for cooling the home s living space. With water on a roof. The whitecap system employs the cooling of water by night sky radiation convection and evaporation of water in an open water cycle. Cooled water returns via the roof drain system to a 15 000 gallon underground tank.

The metal roof is used at night during spring autumn and acceptable summer periods to perform sensible cooling. The system operates a water spray system on the roof at night cooling the water by evaporation and radiation to the cool night sky. The water cycles through this spray cooling process until it is cooled to. Instead of spraying water on the roof you should apply a cool roof coating to cool your roof down.

Cool roof coatings are white or special reflective pigments that reflect sunlight. The water filled plastic bags are covered by a roof in the daytime and at night times is moved away on rollers to expose the water to the night sky. The most common radiative coolers found on buildings are white cool roof paint coatings which have solar reflectances of up to 0 94 and a thermal emittances of up to 0 96. Warm hydronic fluid from the building is pumped through flat plate solar panels at night and is cooled by radiant heat loss to the night sky.

Another radiation cooling system has been the oretically and experimentally investigated by al nimr et al 1998. David lives in castlemaine victoria australia with hot and dry summers. This water is first cooled by evaporation during the spray process and then further cooled by radiation to the night sky. If made sufficiently reflective to sunlight these materials can also achieve radiative cooling during the day.

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. The water is then collected via a gutter system and returned the tank. During the cooling season water is sprayed over the roof surface at night. Cooled by the night s temperature the water is funneled through roof gutters and rainwater leaders and then stored in a thermal storage tank to be used by the building s radiant cooling system with tubing located in the floor slabs and ceiling panels.