SOLAR REFRIGERATOR

A solar-powered refrigerator is a refrigerator which runs on energy directly provided by sun, and may include photovoltaic or solar thermal energy. Solar-powered refrigerators are able to keep perishable goods such as meat and dairy cool in hot climates, and are used to keep much needed vaccines at their appropriate temperature to avoid spoilage. Solar-powered refrigerators are typically used in off-the-grid locations where utility provided AC power is not available. Traditionally solar-powered refrigerators and vaccine coolers use a combination of solar panels and lead batteries to store energy for cloudy days and at night in the absence of sunlight to keep their contents cool. These days, solar refrigerators feature no battery at all. Instead, the change of the refrigerants phase from gas to liquid produces enough thermal energy to keep the fridge going without a source of sunshine. This way, no batteries are required to power solar refrigerators at night.
Modern designs use wireless technology and fuzzy control theory for battery management. The street lights using this technology can operate as a network with each light having the capability of performing the turning on and off of the network