"Heat exchanger for energy recovery from the flues. Exhaust fumes = Free energy The “ECONOMIZER” heat exchanger patented by CORAL, allows to recover the heat lost into the atmosphere from the combustion fumes of the industrial heaters or other hot fluids, sending hot air into the environment. Operating principle: The “ECONOMIZER” is a shell and tube exchanger with cross flow, preferably mounted vertically on the fume expulsion flues; passing upwards through the pipes, the fumes give up the heat to the cross flow of air generated by the helicoidal fan EER and spreads through the environment via the front vent with moveable fin or through ducts. The shell and tube is covered in galvanised sheet panels. Operating temperature not less than 180°C controlled by a minimum thermostat to prevent the formation of condensate in the chimney."