Solar panel are used to generate the amount of energy flowing from one body to another spontaneously due to their temperature difference, or by any means other than through work or the transfer of matter called heat.
 Also, high-cost, high-efficiency, and close-packed rectangular multi-junction (MJ) cells are usually used in solar panels on spacecraft, as they offer the highest ratio of generated power per kilogram lifted into space
 Such heat transfer occurs by conduction or by thermal radiation

