What is the difference between gas-fired boiler and condensing gas-fired boiler in working principle?

(1) The Introduction of Gas-fired Boiler’s Working Principle

The gas-fired boiler is a kind of thermal energy conversion equipment that burns fuel gas such as natural gas, liquefied gas, town gas and so on to generate heat that vaporizes the water in the boiler into steam.

Principle: heated by energy generated from the combustion of fuel gas in the furnace, the water in the drum generates steam with pressure. Due to the boiler is well-sealed and the boiling point of water rises with pressure, the expansion of water vapour is limited to produce pressure and then form thermal power (To be strict, water vapour is formed by heating the water in the drum with constant pressure to form saturated water into vaporization process) that is a kind of widely-used energy.

(2) The Introduction of Condensing Gas-fired Boiler’s Working Principle

The working principle of condensing gas-fired boiler is to use special device to recycle the energy contained in the hot smog (about 140℃) generated by boiler combustion. The temperature of exhaust gas is about 60℃ after recycling, which means there is 10% fuel gas is saved and thermal efficiency enhances by 10%; meanwhile, the recycling of energy also helps to lower the emission of harmful gas and reduce environmental pollution.

(3) The Comparison between Gas-fired Boiler and Condensing Gas-fired Boiler

The temperature of exhaust gas is 160~250℃ or higher for the traditional boiler, so that the water generated by fuel combustion is in the state of superheated steam in the smog. Due to the heat loss of smog from chimney, the thermal efficiency of traditional boiler is only 85%-91%.

However, the condensing gas-fired boiler can lower the temperature of exhaust gas to 50~70℃ and completely recycle the heat contained in the smog and potential heat generated from the condensation of water vapour. The process can save a lot of energy and the thermal efficiency can reach 109%.

Those above are the working principles of gas-fired boiler and condensing gas-fired boiler. In general, gas-fired boiler uses natural gas to heat water in order to provide heat source for underfloor heating and heating radiator, while condensing gas-fired uses condensation technology to recycle the thermal energy from the exhaust gas.