A vapor absorption refrigeration system provides cooling using a heat source rather than electrical input as in the more familiar vapor compression cycle. It seems unreasonable that cooling can be achieved with heat, but that is what occurs within an absorption system.The differences cause an absorption system to use little to no work input, but energy must be supplied in the form of heat. This makes the system very attractive when there is a cheap source of heat, such as solar heat or waste heat from electricity or heat generation. Absorption chillers have recently gained widespread acceptance due to their capability of not only integrating with cogeneration systems but also because they can operate with industrial waste heat streams.