Passive temperature regulation of outdoor cabinets and shelters using pure water and night sky radiation

Passive air conditioning of outdoor cabinets and shelters has been performed for many years. Heat from the equipment is stored in a thermal mass as latent heat then disposed of through a heat exchanger to the relatively cool night air. During the hottest time of the year, sky temperature is often at least 15°C below ambient, allowing 60 watts/M² to radiate outward even after the radiator has cooled to ambient temperature. To explore night sky radiation the radiator is larger than the shelter roof, giving both day time shade and extra night cooling. The water is its own thermostat because it ceases to flow by convection to the radiator at 4°C, the temperature of maximum density. Water´s high (80 cal/gram) heat of fusion makes it the perfect medium for storing heat to prevent cabinets from cooling below 0°C. All components must be freeze tolerant