Economizer
![One of two original 1940's 'Green's Economizers' inside the Killafaddy Board Mills boiler house on the outskirts of Launceston](/Images/godic/202501/12/A_1940's_'Green's_Economizer'_in_a_boiler_house_in_Launceston,_Tasmania3642.JPG")
![Two staged systems may need to double the pressure handlers installed in the cycle. The diagram displays two different thermal expansion valves (TXV) and two separate stages of gas compression.](/Images/godic/202501/12/Two_Staged_System3642.png")
![A subcooled booster has a subcooling heat exchanger (SHX) that provides subcooling for the condensed liquid line.](/Images/godic/202501/12/Subcooled_Booster3642.png")
![Some screw compressor manufacturers offer them with economizer. This systems can use flash-gas for the economizer input.](/Images/godic/202501/12/Flash_Economiser3642.png")
Economizers (US and Oxford spelling), or economisers (UK), are mechanical devices intended to reduce energy consumption, or to perform useful function such as preheating a fluid. The term economizer is used for other purposes as well. Boiler, power plant, heating, Refrigeration, ventilating, and air conditioning (HVAC) uses are discussed in this article. In simple terms, an economizer is a heat exchanger.