Total flue gas waste heat recovery system and method for gas boiler or direct-fired machine

Abstract

The invention discloses a total flue gas waste heat recovery system and method for a gas boiler or a direct-fired machine. The total flue gas waste heat recovery system comprises the gas boiler or the direct-fired machine, one or more heat exchangers, an induced draft fan, one or more condensers and a heat pump. A high-temperature flue gas channel of the gas boiler or the direct-fired machine is connected with the heat exchangers, the induced draft fan and the condensers in sequence. The flue gas output end of each condenser is connected with the outdoor place. Hot water connection of the flue gas waste heat recovery system includes a parallel connection manner and / or a series connection manner. The parallel connection manner is characterized in that a hot water return pipe is divided into two ways to be connected with the heat exchangers and the heat pump respectively, and the output of the heat exchangers and the output of the heat pump are connected with a heating system. The series connection manner is characterized in that the hot water return pipe is connected with the heat pump, outlet water of the heat pump is connected with the heat exchangers, and the output of the heat exchangers is connected with the heating system. By means of the total flue gas waste heat recovery system, the flue gas waste heat of the gas boiler or the direct-fired machine is totally recycled and used for heating, sanitary water heating, replenished water heating and other kinds of technological application, and the aims of saving energy, reducing consumption and reducing emission are achieved.

Description

technical field [0001] The invention belongs to the technical field of energy-saving and environment-friendly equipment, and in particular relates to a system and method for recovering the waste heat of flue gas from a gas-fired boiler or a direct-fired machine. Background technique [0002] At present, a considerable part of the heat energy of gas-fired boilers or direct-fired engines is wasted with flue gas emissions. However, the flue gas waste heat recovery technology introduced in the field of waste heat recovery and the exhaust gas temperature of the condensing boiler are also above 40°C, and there is still a large amount of waste heat that is difficult to recycle. Therefore, the current so-called "waste heat" recovery technology only recovers part of the latent heat, and does not really realize the full heat recovery of natural gas heat energy. Contents of the invention [0003] The technical problem to be solved by the present invention is: to solve the problems e...

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Problems solved by technology

[0002] At present, a considerable part of the heat energy of gas-fired boilers or direct-fired engines is wasted with flue gas emissions.

However, the flue gas waste heat recovery technology introduced in the field of waste heat recovery and the exhaust gas temperature of the condensing boiler are also above 40°C, and there is still a large amount of waste heat that is difficult to recycle.

Therefore, the current so-called "waste heat" recovery technology only recovers part of the latent heat, and does not really realize the full heat recovery of natural gas heat energy.

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