Night Radiative Cooling (PA Technology)

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Last modified by Franz Schreier on 2014-12-28. This is a wiki so please feel free to update information by clicking on "Edit with form". | Printable version

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Name of technology example:		Type
Night Radiative Cooling		☐ Energy Efficiency ☑ Renewable Energy ☑ Alternative Methodology

Description	All objects constantly emit and absorb radiant energy. At night, the long-wave radiation from the clear sky is less than the long-wave infrared radiation emitted from a building, thus there is a net flow to the sky. Since the roof provides the greatest surface visible to the night sky, designing the roof to act as a radiator is an effective strategy. There are two types of radiative cooling strategies that utilize the roof surface: direct and indirect. Direct radiant cooling - In a building designed to optimize direct radiation cooling, the building roof acts as a heat sink to absorb the daily internal loads. The roof acts as the best heat sink because it is the greatest surface exposed to the night sky. Radiate heat transfer with the night sky will remove heat from the building roof, thus cooling the building structure. Roof ponds are an example of this strategy. The roof pond design became popular with the development of the Sky thermal system designed by Harold Hay in 1977. There are various designs and configurations for the roof pond system but the concept is the same for all designs. The roof uses water, either plastic bags filled with water or an open pond, as the heat sink while a system of movable insulation panels regulate the mode of heating or cooling. During daytime in the summer, the water on the roof is protected from the solar radiation and ambient air temperature by movable insulation, which allows it to serve as a heat sink and absorb, though the ceiling, the heat generated inside. At night, the panels are retracted to allow nocturnal radiation between the roof pond and the night sky, thus removing the stored heat from the day’s internal loads. In winter, the process is reversed so that the roof pond is allowed to absorb solar radiation during the day and release it during the night into the space below. Indirect radiant cooling - A heat transfer fluid removes heat from the building structure through radiate heat transfer with the night sky. A common design for this strategy involves a plenum between the building roof and the radiator surface. Air is drawn into the building through the plenum, cooled from the radiator, and cools the mass of the building structure. During the day, the building mass acts as a heat sink. (Source:http://en.wikipedia.org/wiki/Passive_cooling#Radiative_cooling)
Technology for the Application of	☐ Solar ☐ Biomass ☐ Biofuel ☐ Biogas ☐ Wind ☐ Geo-Thermal ☐ Hydro ☐ Energy Efficiency ☑ Other: Natural Cooling
Primarily Relevant for the following Agricultural Value Chain Steps	☐ Mechanization ☐ Efficiency of Operation ☑ Processing ☐ Transportation ☐ Controlled Atmosphere ☐ Controlled Temperature ☐ Mechanical Sorting ☐ Preservation ☐ Other: /
Primarily Relevant for the following Agricultural Value Chain Activities	☐ Grinding ☐ Hauling and conveying ☐ Sorting ☐ Seedbed Preparation ☐ Milling ☐ Tearing ☐ Planting ☐ Washing ☐ Mixing ☐ Pumping ☐ Heating ☑ Drying ☐ Irrigation ☑ Cooling ☐ Animal feeding ☐ Fertilizing ☑ Venting ☐ Animal health and Welfare ☐ Pest Management ☐ Lighting ☐ Packing and branding ☐ Cutting ☐ Sanitation ☐ Other: /
Primarily Implemented in the following Commodity Groups	☐ Cereals ☐ Fruits and vegetables ☐ Nuts and berries ☐ Forage ☐ Dairy products ☐ Meat products ☐ Oil Seeds ☐ Roots and Tubers ☐ Eggs ☐ Pulses ☐ Fiber Crops ☐ Forestry ☐ Sugars ☐ Stimulants ☐ Spices ☑ Other: All commodity groups with cooling requirements
Region & Country of Development	None ☐ Africa ☐ South Asia ☐ East Asia & The Pacific ☐ Europe & Central Asia ☐ Latin America & The Caribbean ☐ Middle East & North Africa ☐ North America ☐ N/A: /
Region & Country of Current Deployment	Worldwide ☑ Africa ☑ South Asia ☑ East Asia & The Pacific ☑ Europe & Central Asia ☑ Latin America & The Caribbean ☑ Middle East & North Africa ☑ North America ☐ N/A: /
Region & Country of Potential Deployment	Worldwide ☑ Africa ☑ South Asia ☑ East Asia & The Pacific ☑ Europe & Central Asia ☑ Latin America & The Caribbean ☑ Middle East & North Africa ☑ North America ☐ N/A: /
Manufacturers	Different activities and basic technologies, see links below;
Economics	Uses natural cooling potentials, in some cases only a few electricity (for small pumps) and no fuels necessary;
Technology Development Level	Research and development and first pilot installations;
Required Maintenance Technical Level	Basic: Technology can be maintained through its life cycle with common tools and a universally understood maintenance manual;
Required Infrastructure for Deployment	Low: Technology can be developed with less common tools, low development level supporting technologies and moderately trained personnel;
Required Resources during manufacture	Metal, plastics, glass, films, depending on type and developed production facility
Required Resources during operation	In some cases electricity;
Deployment Level	Research and development and Prototype testing;
Deployment Capability and Potential	High: The technology can be widely deployed limited only by education
Requirements for Deployment	Independent: Fully autonomous and self-supportingelectricity supply
Relevance for Autonomy and Food Security	Independent: Fully autonomous and self-supporting;
Environment Impacts (emissions)	Low: no direct emissions but indirect emissions;
Conformity with Bio- Cybernetic System Rules	high
Additional information / Comments	No comments.
Internal Reference
Additional Links	http://en.wikipedia.org/wiki/Passive_cooling#Radiative_cooling http://en.wikipedia.org/wiki/Radiative_cooling http://www.asterism.org/tutorials/tut37%20Radiative%20Cooling.pdf http://www.youtube.com/watch?v=544jTj0gpqY http://cedarmountainsolar.com/nightskyradiantcooling.php?PageID=5_TrueID%3D5 http://solarwall.com/en/products/nightsolar-air-cooling.php http://www.builditsolar.com/Experimental/RadiationCool/EvaproRad.htm http://www.understandingnano.com/nanophotonic-radiative-cooling.html http://misfitsarchitecture.com/2013/03/01/its-not-rocket-science-5-night-sky-radiant-cooling/ http://storage5.net/r/radiative-cooling-pdf.pdf http://www.nhbs.com/title/view/175686

"Renewable Energy, Alternative Methodology" is not in the list (Energy Efficiency, Renewable Energy, Alternative Methodology) of allowed values for the "PAT Type" property.