The world has in a way come up with many energy saving plans from, energy saving bulbs, water heaters and cooling systems. Solar energy has been seen as an alternative to artificial power supply to the high cost of producing it. Some people use solar energy as a result of not being able to access to electricity. According to NASA, 2 billion people across the world have no access to electricity.
Among these people some are lucky to access solar panels which convert sunlight into electricity and used to charge phones, watch television, radio and even International Space Station. The technology uses photovoltaic (PV) cells to convert sunlight to electricity. When the cooling system is provided with electricity it works more the same as the normal fridge used at our homes.
Photovoltaic Cells
There are two layers of semiconductor materials which are composed of silicon that are vital components of a PV cell. Through a process called doping, crystallized silicon is added impurities intentionally due to its inability to conduct electricity on its own and it is able to create a stage for electric current. Boron is used to dope the bottom layer of the PV which in turn bonds with the silicon to form a silicon charge. Phosphorus is used to dope the top layer of the PV cell and in turn bonds with silicon to form a negative charge. An electric field is produced when there is an electron movement between the p type and the n type semiconductors.
Energy from sunlight knocks electrons loose in both layers when sunlight enters the PV cell. Electrons tend to flow from the n type layer to the p type layer but an electric field between the p type and n type prevents this from happening. The external circuit provides the path for the electrons in the n type to travel to p type layer. The n type layer has extremely thin wires that run along which also provide an external circuit. The electrons flowing through this circuit provide a supply of electricity to the cooling system.
Cooling System
The only difference between the way an electric fridge and a solar powered cooler is the fact that you plug the compression-expansion system into a solar panel set up instead of a power grid. The cooler uses the vapor-compression system. A gas like ammonia (usually used for refrigeration) is placed under pressure till it is hot.
When this gas cools down it condenses into liquid which when passed through a lower pressure area expands and evaporates. During this evaporation the vaporous gas cools the inside of the cooler. It would hit a constant temperature of around 38 degrees F/ 3 degrees Celsius. To be able to supply enough power supply for the temperature to remain constant at least five hours of sunlight a day is required. They are also built to stay for long without sunlight by storing excess solar generated energy called the backup system.