Solar cooling is one of the ways solar energy is adopted to preserve food items and vaccines at the required temperatures, particularly in tropical undeveloped countries where power supply can sometimes be unreliable. Storage is necessary to reduce post-harvest losses. However, a crucial question might be how does the heat and light radiating from sunlight cause cooling?
In Maruata, a village located 18 degrees north of the equator on the Mexican pacific coast and a predominant fishing community have been able to store fish using ice makers powered by the sun for over 16 years. Cooling from the sun can be achieved through Solar PV Refrigerators and Solar Thermal Refrigerators.
Solar-Photovoltaic(PV) refrigerator runs on energy from sunlight converted by photovoltaic panels. It is heavily insulated and uses batteries that sometimes deteriorate because of the heat in tropical regions.
Solar thermal refrigerators use heat from the sun to convert the refrigerant from vapour to liquid. This is similar to what electric-powered refrigerators do with compressors. The common combinations of refrigerants are lithium bromide or ammonia. The refrigerant condenses into a liquid at high pressure and back to gas at low pressure. The heat moderates the pressure to cause cooling.
This technology addresses the challenge of the cost of refrigeration systems making cooling accessible to remote areas without electricity. This technology will help improve food security by enabling cold storage and reducing post-harvest losses.