CT: Condensing boilers use heat from exhaust gases that would normally be released into the atmosphere through the flue. To use this latent heat, the water vapour from the exhaust gas is turned into liquid condensate.
S: WORCESTER – http://www.worcester-bosch.co.uk/homeowner/boilers/what-is-a-condensing-boiler (last access: 16 December 2014)
N: 1. condensing (adj): from condense. Early 15c., from Middle French condenser (14c.) or directly from Latin condensare “to make dense,” from com-, intensive prefix, + densare “make thick,” from densus “dense, thick, crowded,” a word used of crowds, darkness, clouds, etc.
boiler (n): 1540s, agent noun from boil (v.). Meaning “vessel for boiling” is from 1725; steam engine sense is from 1757.
2. In order to make the most of the latent heat within the condensate, condensing boilers use a larger heat exchanger, or sometimes a secondary heat exchanger.
3. Due to this process, a condensing boiler is able to extract more heat from the fuel it uses than a standard efficiency boiler. It also means that less heat is lost through the flue gases.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=boiler&searchmode=none (last access: 16 Dicember 2014); EO. 2 & 3. WORCESTER – http://www.worcester-bosch.co.uk/homeowner/boilers/what-is-a-condensing-boiler (last access: 16 December 2014).