Flue gas total-heat recovery device of gas boiler

Abstract

The invention relates to a flue gas total-heat recovery device of a gas boiler, belonging to the thermotechnical field. In the invention, the temperature of the flue gas exhausted by the gas boiler can be reduced to lower than 40 DEG C by a gas-water heat exchanger and a mixing cooler, then the cooled flue gas is directly supplied for an air-source heat pump water heater for generating the hot water, and the sensible heat and the latent heat in the flue gas can be totally recovered. Most CO2 and NOx in the flue gas can be absorbed by condensed water in the cooling process, thereby reducing the emission of harmful gas. The device comprises the gas-water heat exchanger, the mixing cooler and the heat pump water heater and is characterized in that the flue gas at 150-200 DEG C is cooled to lower than 90 DEG C by the gas-water heat exchanger and then can be cooled to lower than 40 DEG C in the mixing cooler, and the cooled flue gas can serve as heat source to directly enter an evaporator of the air-source heat pump water heater for heat exchange. The invention solves the problems of frosting and low efficiency of the air-source heat pump water heater due to low temperature in winter in the North while recovering the residual heat of the flue gas of the gas boiler at the same time; meanwhile, the emission of the harmful gas in the flue gas of the gas boiler can be reduced, thereby realizing energy saving and emission reduction.

Description

technical field [0001] The invention relates to a device for total heat recovery of gas boiler flue gas, belonging to the field of thermal engineering. Background technique [0002] In order to reduce the pollution of boiler flue gas to the urban atmosphere, many cities restrict coal-fired boilers and vigorously develop gas-fired boilers fueled by clean natural gas. At present, the exhaust gas temperature of gas boilers is about 150 degrees, especially in the heating season in the north, a large amount of heat energy is discharged into the air and wasted. In the prior art, after the gas-water heat exchanger is used to recover the heat of the flue gas, the exhaust temperature of the flue gas is still above 90°C. [0003] Air source heat pump water heater is the current water heater with energy saving, environmental protection and high energy efficiency ratio. It is developing rapidly in the south of the Yangtze River in my country. However, in the north, due to the low temp...

AI Technical Summary

Problems solved by technology

However, in the north, due to the low temperature in winter, the evaporator of the air source water heater is frosted and the energy efficiency ratio of the water heater is reduced, which restricts the popularization and development of this technology in the north.

Images