... , about the high heat of 10%.Flue gas condensing heat recovery unit, the use of low-temperature water or air-cooled flue ... heat water or air to be heated, to achieve energy recovery, increase the boiler thermal efficiency.Boiler thermal efficiency: 1NM3 the ... , if the check 80 % of flue gas entering the heat recovery unit can increase the utilization of geothermal energy for more than ...