A Brief History of Refrigeration

Although these systems are far less widely used than compression systems, they are the only thermal refrigerating systems that are currently encountering a degree of development. In these systems, instead of using a mechanical compressor to circulate the refrigerant, a pump is used to circulate an absorbent liquid, the quantity of which, in terms of absorbed refrigerant, depends on the temperature and the pressure. The mechanical work is very reduced; however, this system
requires heat.