Why is the thermal efficiency of a gas steam boiler greater than 100%?
2019 / Jun / Mon
First of all, we must first know what is the high calorific value and low calorific value of the gas steam boiler fuel?
The fuel calorific value is divided into high calorific value and low calorific value. High calorific value: All the heat released when the fuel is completely burned, including the latent heat of vaporization from the condensation of water vapor in the flue gas into water.
Low calorific value: The latent heat of vaporization of water vapor in the flue gas is deducted from the high calorific value of the fuel.
High calorific value = low calorific value + latent heat of vaporization of water vapor
The low calorific value is the closest to the actual calorific value of industrial boilers. It is often used in design calculations. That is to say, the efficiency of the original boiler is not considered as part of the latent heat of vaporization in 11% of the exhaust gas.The thermal efficiency of the general boiler is 90. ~92%. Therefore, when calculating the boiler efficiency with low calorific value, if the condensation technology is utilized to utilize the latent heat of vaporization and partial sensible heat in the exhaust gas, the efficiency may be greater than 100%.