What is a high efficiency condensing boiler?
A high efficiency condensing
boiler works on the principle of recovering as much as
possible of the waste heat which is normally rejected to the
atmosphere from the flue of a conventional (non-condensing)
boiler. The best high efficiency condensing boilers convert
more than 90% of their fuel into heat, compared to 78% for
conventional types.
This is accomplished by using
a larger heat exchanger or sometimes two heat exchangers
within the boiler which maximises heat transfer from the
burner as well as recovering useful heat which would
normally be lost with the flue gases. When in condensing
mode (condensing boilers do not condense all the time) the
flue gases give up their 'latent heat' which is then
recovered by the heat exchanger within the boiler. As a
result the temperature of the gases exiting the flue of a
condensing boiler is typically 50-60°C compared with
120-180°C in a current non-condensing boiler. At the same
time an amount of water or 'condensate' is produced.
A condensing boiler will always have a better operating efficiency than a conventional non-condensing one due to its larger and more efficient heat exchanger. |