In systems involving heat transfer, a condenser is a device or unit used to condense substance from its gaseous to its liquid state, by cooling it. In so doing, the latent heatis given up by the substance and transferred to the surrounding environment. Condensers can be made according to numerous designs, and come in many sizes ranging from rather small (hand-held) to very large (industrial-scale units used in plant processes). For example, a refrigerator uses a condenser to get rid of heat extracted from the interior of the unit to the outside air. Condensers are used in air conditioning, industrial chemical processes such as distillation, steampower plants and other heat-exchange systems. Use of cooling water or surrounding air as the coolant is common in many condensers.