Refrigeration is a branch of science that deals with the process of removing heat from a substance or space in order to make it cooler.
Refrigerator is defined as a device that is used in cooling the internal temperature below the room temperature (that is between 250C to 300C).Generally, however, for a space or substance to be cooler, it must loss that heat to another. Also, for a space or substance to get hotter, it must absorb heat from another, which must be at higher temperature. For both process to occur, heat must be absorbed or lost, thus heat is the characteristics agent of heating and cooling, consequently, for heat flow there is absorbs at a lower temperature region and rejected at a higher temperature region, which is the quantity being determined by the temperature gradient of the two regions.