The flue gas temperature of ordinary hot water boilers during combustion is very high, about 130 degrees, which takes away a lot of heat. The condensing boiler condensing combustion technology reduces the flue gas temperature to 50 degrees, condenses part of the flue gas into a liquid state, and absorbs the flue gas. The heat from gas to liquid is recovered, that is, the heat originally taken away by the flue gas is recovered, so the thermal efficiency is much higher than that of ordinary boilers.
Since the heat carried by the high-temperature flue gas is not considered when calculating the thermal efficiency of the boiler, and the condensing boiler utilizes this part of the heat, the thermal efficiency of the condensing boiler exceeds 100%.
The amount of latent heat of water vapor in the flue gas that can be recovered by the condensing boiler is related to the type of fuel used by the boiler and the outlet water temperature of the boiler. When an ordinary boiler without a condensing recovery device burns natural gas, if the thermal efficiency of the boiler is calculated as 90% based on the low calorific value of the fuel, after using a condensing waste heat recovery device, the exhaust gas temperature will drop to 30 ~ 50 ℃, and its thermal efficiency will be improved. to about 108%. Under the condition of constant fuel consumption, the lower the return water of the heating system, the more heat recovered by the condensing waste heat recovery device, and the higher the thermal efficiency of the boiler. For the water-ring water source air conditioner that uses the boiler to provide heat energy in winter, the temperature of the hot water for heating is 25°C, and the use of a condensing boiler saves a considerable amount of operating costs compared with ordinary hot water boilers. Taking a 1 million kcal/h boiler as an example, the natural gas consumption of an ordinary boiler is 126.5Nm3/h (the low calorific value of natural gas is 8500kcal/Nm3), and the natural gas consumption of a condensing boiler is 110 Nm3/h. If the boiler runs for 10 hours a day, If the heating cycle is 100 days, the use of condensing boilers can save 16,500 Nm3 of natural gas per year, and the annual operating cost can be saved by 29,700 yuan based on the natural gas price of 1.8 yuan.
Fuel combustion will produce a large amount of CO2, NOX and a small amount of SO2. These substances are emitted to the atmosphere, which will cause the greenhouse effect and the production of acid rain, which will cause damage to the environment. The condensing boiler can easily remove these harmful substances in the flue gas while condensing the water vapor in the flue gas. Therefore, the use of a condensing boiler is also of great significance to protect the environment.