Economisers or heat exchange systems

These systems can recover heat from the flue for preheating boiler feedwater. This option is especially effective if not all condensate is returned to the boiler. Direct-contact economisers spray water directly into the flue gas, which also remove particles and acid gases such as sulphur dioxide (SO2).

Air preheaters

Air preheaters are used to heat the inlet air to increase combustion efficiency and can use recovered heat from the flue gases as well as warm air from the boiler room ceiling or even solar panels.