Condensate pre-heater outside the boiler

Condensate pre-heater outside the boiler

Condensate pre-heater outside the boiler

The condensate pre-heater in this system is outside the boiler and the heat is indirectly drawn from the flue gases via the economizer. The condensate is heated by means of the hot feedwater from the deaerator.

Advantages over systems with pre-heating in the boiler:

  • The condensate pre-heater is located outside of the boiler and is very compact (e.g. a plate heat exchanger)
  • Performance is less sensitive to the performance of the boiler

Disadvantages over systems with pre-heating in the boiler:

  • Reduced unit output (higher boiler inlet temperature)
  • The need to regulate condensate temperature in the external pre heater.

Systems with condensate pre-heating are slightly more complex due to the requirement of the pre-heater and associated controls. In addition, the steam for the deaerator must be extracted from a higher pressure source.