Modern refrigerators use a regenerating cycle to reuse the same refrigerant over and over again. To understand how refrigeration works, lets assume that the refrigerant being used is pure ammonia, which boils at -27 degrees F, because many modern large industrial refrigerators still use ammonia. When the refrigerating unit is cooling, what is known as the compressor compresses the ammonia gas. The compressed gas then heats up caused by pressurization. From there, the coils usually found on the back of the refrigerator let the hot ammonia gas release its heat. The ammonia gas condenses into ammonia liquid at high pressure. The high-pressure ammonia liquid flows through the expansion valve, basically a small hole. On one side of the hole is high-pressure ammonia liquid, on the other is a low pressure area, caused by the compressor sucking gas out. The liquid ammonia instantaneously boils and vaporizes, its temperature dropping to -27 F. This makes the inside of the refrigerator cold. The cold ammonia gas is then sucked up by the compressor, and the cycle repeats. Complicated though refrigeration may be, it is necessary as, it helps remove toxic chemical from the area in which the unit is placed. Refrigeration is used to maintain certain processes at their required low temperatures, so if your company deals in food storage, your products will not go bad due to temperature, good news for those who handle temperature-sensitive foodstuffs. Food can also be ruined due to moisture and refrigeration condenses water vapor to reduce moisture content. If you have ever turned your car off on a hot summer day when you have had the air conditioner running, you may have heard a hissing noise under the hood. That noise is the sound of high-pressure liquid refrigerant flowing through the expansion valve. So you've experienced or been exposed to an aspect of industrial refrigeration without knowing it!