Refrigeration

Refrigeration is the artificial cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient temperature. Early refrigeration uses consumable coolants such as ice and dry ice, while modern refrigeration is a self-sustaining heat exchanger process by which thermal energy is transferred against the temperature gradient via the use of a heat-transfer working fluid, which absorbs heat from a low-temperature medium and releases it to another higher-temperature m