Solar absorption refrigeration is a great innovation for those who don’t have access to the electrical grid. It can keep vital vaccines and food cool by using solar energy. Small agricultural enterprises in remote areas can store their products longer until they can get them to market. There are two kinds of solar refrigerators. They use an absorption system, or they are connected to a solar panel which supplies electricity that runs the refrigerator’s compressor.
An absorption refrigerator uses solar heat as energy for the cooling system. This type of refrigerator uses a refrigerant with a low boiling point. Ammonia mixed with water is commonly used as a refrigerant. When heat is applied the temperature and pressure rise. When the heat is turned the pressure lowers and the liquid evaporates back into gas providing a cooling effect.
Set up the Troughs
Attach the parabolic troughs to their stands and place them end to end. Position this east to west and in the direction of the most direct sun, Fasteners will be included with the troughs.
Mount the Generator
Fill the steel pipe with calcium chloride and cap both ends. Mount the pipe on the two parabolic troughs. This is the generator pipe.
Connect the Condenser
Connect the generator pipe to the condenser coil with a stainless steel valve. Place the condenser coil in the drum which is being used as the condenser tank.
Set up the Storage Tank
Weld the two steel plates to either end of the shorter 3-inch pipe. The other end of the condenser coil should be joined to the storage tank with another valve. All connections should be welded to be airtight.
Prepare the Ice Box
Insert the storage tank in the icemaker box (chest freezer or box). Put water in the condenser tank to make a bath for cooling. Place a couple of bags around the storage tank.
Anhydrous ammonia in a pressurized tank evaporates into the generator via the valve. The generator pipe heats up and boils it out of the pipe, In the condenser coil, the gas turns to liquid. It drips into the storage tank below. At night the liquefied ammonia produces ice in the bags around the storage tank which keeps the icebox cool.
Ammonia is caustic and can be dangerous to work with. Be sure not to inhale it or get it near your eyes or nose. If there is a leak in the system, water should be readily available to dilute the ammonia and for cleanup.