Heat exchanger for flue gas waste heat recovery of gas water heater

Abstract

The invention discloses a heat exchanger for flue gas waste heat recovery of a gas water heater, and relates to the technical field of heat transfer, the heat exchanger comprises a collecting shell, the collecting shell is located above a heat exchange chamber, a gas guide plate is arranged in the collecting shell, the gas guide plate is in an arc shape, a collecting groove is formed in the collecting shell, a horn collecting opening is formed in the collecting shell, and the horn collecting opening is located in the collecting shell. The first heat pipes are installed in the collecting shell in a matched mode, one ends of the first heat pipes are located above the horn collecting opening, the first heat pipes are arranged in a fan shape, and the other ends of the first heat pipes extend out of the collecting shell and are provided with a first heat exchange sheet set in a matched mode. And the cold water pipe penetrates through the first heat exchange sheet group and is matched with the first heat exchange sheet group. According to the invention, the first heat pipes are arranged in the fan-shaped array, so that the first heat pipes are in space coupling matching with fan-shaped diffusion flue gas guided out from the horn-shaped convergent opening, and the contact area is maximized through collaborative design of geometric morphology.

Description

Technical Field

[0001] The invention relates to the technical field of heat transfer, in particular to a heat exchanger for recovering waste heat from flue gas of a gas water heater. Background Art

[0002] A gas water heater is a type of water heater that uses gas as its main energy material. The high-temperature heat generated by the combustion of gas is transferred to the cold water flowing through the heat exchanger to reach the required temperature of hot water. It has the advantages of being able to be used immediately and having a small footprint. Current gas water heaters generally ignite gas in the combustion chamber and use open flames to heat the water in the heat exchange coil. After the temperature reaches a certain level, the water is discharged through the hot water pipe for use.

[0003] However, after the combustion of gas, a certain amount of flue gas with heat will be generated. At present, this flue gas is mainly recovered through heat pipes (heat pipes are generally hollow cylindrical tubes. When a temperature difference occurs at both ends of the heat pipe, the liquid at the evaporation end will quickly vaporize and bring the heat to the condensation end at a very fast speed). When in use, one end of the heat pipe is connected to the cold water pipe for heat conduction, and the other end of the heat pipe goes deep into the exhaust pipe to absorb the heat; However, the contact area between the high-temperature gas and the heat pipe is relatively small, and the high-temperature flue gas enters the flue gas inlet at a relatively fast speed, which shortens the contact time between the high-temperature flue gas and the heat pipe. As a result, the heat pipe absorbs less heat from the flue gas, resulting in energy waste and increasing the monthly gas usage in the user's home. In addition, these flue gases contain a certain amount of water vapor (obtained from the combustion of natural gas), and the condensation of water vapor in the exhaust pipe will cause the condensed water to flow back, causing danger. Summary of the invention

[0004] In order to solve the problem of incomplete waste heat recovery of flue gas from water heaters mentioned in the above background technology, an object of the present invention is to provide a heat exchanger for recovering waste heat from flue gas from a gas water heater.

[0005] To achieve the above object, the present invention provides the following technical solution: a heat exchanger for recovering waste heat from flue gas of a gas water heater, comprising a heat exchange chamber, a combustion chamber, a gas combustion tank, and an air intake fan which are sequentially installed from top to bottom; a heat exchange coil is arranged in the heat exchange chamber, and a cold water pipe and a hot water pipe are respectively installed at both ends of the heat exchange coil, and further comprising: A convergence shell, the convergence shell is located above the heat exchange chamber, an air guide plate is arranged inside the convergence shell, the air guide plate is in an arc shape, a convergence groove is opened on the convergence shell, and the convergence shell forms a trumpet convergence port; A plurality of first heat pipes are installed in cooperation inside the convergence shell, one end of the first heat pipe is located above the horn convergence port, the first heat pipes are arranged in a fan shape, the other end of the first heat pipe extends out of the convergence shell and is installed in cooperation with a first heat exchange plate group, and the cold water pipe passes through the first heat exchange plate group and is arranged in cooperation with it.

[0006] Furthermore, an exhaust gas heat recovery chamber is installed on the convergent shell, and a plurality of exhaust gas heat recovery control devices are installed in the exhaust gas heat recovery chamber. The upper end of the exhaust gas heat recovery chamber is connected to an exhaust pipe through a collecting shell.

[0007] Furthermore, the exhaust gas heat recovery control device includes a first mounting plate and a second mounting plate, the first mounting plate and the second mounting plate are arranged in parallel, and the first mounting plate is located above the second mounting plate.

[0008] Furthermore, a rotating shaft is mounted on one end of the first mounting plate, and two baffles arranged opposite to each other are mounted on the rotating shaft.

[0009] Furthermore, a slot is provided on the first mounting plate, and the baffle is engaged with the slot.

[0010] Furthermore, a partition is installed in the exhaust gas heat recovery chamber, and a limit plate is provided on one side of the partition.

[0011] Furthermore, a fast-pass opening is formed between the first mounting plate and the limiting plate, a slow-pass opening is formed between one end of the first mounting plate and the exhaust gas heat recovery chamber, and a smoke inlet is provided between one end of the second mounting plate and the partition.

[0012] Furthermore, a protective pad is installed in the convergence groove, a steering gear is embedded and installed on the protective pad, and the steering gear is driven and connected to the corresponding rotating shaft through a connecting rod mechanism.

[0013] Furthermore, a plurality of second heat pipes are installed between the first mounting plate and the second mounting plate, and one end of the second heat pipe extends out of the exhaust gas heat recovery chamber and is arranged in cooperation with the first heat exchange plate group.

[0014] Furthermore, a plurality of third heat pipes are installed between the first mounting plate and the second mounting plate, one end of the third heat pipe extends out of the exhaust gas heat recovery chamber and is installed with a second heat exchange plate group, and a plurality of temperature sensors are installed in the exhaust gas heat recovery chamber.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention arranges the first heat pipe in a fan-shaped array so that it forms a spatial coupling match with the fan-shaped diffused flue gas derived from the horn convergence port, and maximizes the contact area through the collaborative design of geometric forms. When high-speed flue gas flows through the fan-shaped heat pipe array, the flow velocity gradient is significantly reduced due to the boundary layer effect of the dense tube bundle, forming a turbulent effect, effectively extending the flue gas residence time and improving the convective heat transfer efficiency. According to actual measurements, this structural design improves the sensible heat recovery efficiency and achieves the energy-saving effect of reducing the average monthly gas consumption of a single household.

[0016] 2. This device uses the exhaust gas heat recovery control device to intelligently regulate the flue gas flow channel after the first heat pipe absorbs heat: when the flue gas temperature is higher than the set threshold, the servo controls the baffle to close the quick-pass port, forcing the flue gas to flow along the channel between the first mounting plate and the second mounting plate. During this process, the second heat pipe and the third heat pipe recover the residual heat of the flue gas for a second time; when the flue gas temperature drops below the safety threshold, the servo controls the baffle to switch to the closed slow-pass port state, so that the flue gas directly enters the exhaust pipe through the quick-pass port and is quickly discharged. Through dynamic path control, dual optimization of maximizing waste heat recovery efficiency and accurately preventing and controlling condensation risks is achieved, ensuring that the flue gas temperature is always higher than the dew point to avoid the formation of condensed water inside the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a basic structural schematic diagram of a heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Figure 2 The heat exchanger for recovering waste heat from flue gas of a gas water heater of the present invention Figure 1 The main view; Figure 3 The heat exchanger for recovering waste heat from flue gas of a gas water heater of the present invention Figure 1 A top view of Figure 4 The heat exchanger for recovering waste heat from flue gas of a gas water heater of the present invention Figure 3 A cross-sectional view of BB; Figure 5 The heat exchanger for recovering waste heat from flue gas of a gas water heater of the present invention Figure 4 A magnified view of part A; Figure 6 A cross-sectional view of CC of a heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Figure 7 It is a flow diagram of the flue gas of the heat exchanger for recovering waste heat from flue gas of the gas water heater of the present invention passing through the first heat pipe and the second heat pipe; Figure 8 It is a schematic structural diagram of a tail gas heat recovery control device during the fast-pass of a heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig. 9 It is a structural schematic diagram of the exhaust gas heat recovery control device of the heat exchanger for recovering waste heat from flue gas of a gas water heater during slow flow of the present invention; Fig.10 It is a schematic structural diagram of the exhaust gas heat recovery control device when adjusting the heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig.11 A schematic diagram of the position of the opening of the heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig.12 A schematic diagram of the installation position of a heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig.13 It is a schematic diagram of the internal structure of the heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig.14 It is another schematic diagram of the internal structure of the heat exchanger for recovering waste heat from flue gas of a gas water heater according to the present invention; Fig.15 The present invention is a schematic diagram of the installation position of the heat dissipation fins of the heat exchanger for recovering waste heat from flue gas of a gas water heater.

[0018] In the figure: 101, convergence shell; 102, convergence slot; 103, protective pad; 104, exhaust heat recovery chamber; 105, collection shell; 106, exhaust pipe; 107, partition; 108, air guide plate; 109, horn convergence port; 110, temperature sensor; 201, first heat pipe; 202, first heat exchange plate group; 203, second heat pipe; 204, third heat pipe; 205, second heat exchange plate group; 300, exhaust heat recovery control device; 3 01. Rotating shaft; 302. Baffle; 303. Limiting plate; 304. Slot; 305. First mounting plate; 306. Second mounting plate; 307. Connecting rod mechanism; 308. Servo; 309. Fast-pass port; 310. Slow-pass port; 311. Flue gas inlet; 312. Heat-absorbing fins; 601. Cold water pipe; 602. Hot water pipe; 603. Heat exchange chamber; 604. Combustion chamber; 605. Gas combustion tank; 606. Intake fan; 607. Heat exchange coil. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 - Fig.14As shown, the heat exchanger for recovering waste heat from flue gas of a gas water heater provided in this embodiment is as follows: Fig.12 As shown, it includes a heat exchange chamber 603, a combustion chamber 604, a gas combustion tank 605, and an air intake fan 606 which are installed in sequence from top to bottom; a heat exchange coil 607 is provided in the heat exchange chamber 603, and a cold water pipe 601 and a hot water pipe 602 are installed at both ends of the heat exchange coil 607. When in use, cold water enters the heat exchange coil 607 through the cold water pipe 601. After the heat exchange coil 607 is heated, the heated hot water is discharged through the hot water pipe 602. A water temperature sensor is installed on the hot water pipe 602. The heat exchange coil 607 is heated by the open flame generated by the gas combustion tank 605. The air intake fan 606 of this embodiment is installed below the combustion chamber 604. Air is blown into the combustion chamber 604 through the air intake fan 606 to provide oxygen for the combustion of the gas, and the smoke is discharged through the exhaust pipe 106.

[0021] A convergence shell 101 is installed above the heat exchange chamber 603. Figure 6-7 As shown, an air guide plate 108 is provided in the convergence shell 101. The air guide plate 108 is arc-shaped. The smoke generated by the combustion is guided by the air guide plate 108. A convergence groove 102 is opened on the convergence shell 101. The convergence shell 101 forms a horn convergence port 109 (refer to Figure 6 As shown), a plurality of first heat pipes 201 are installed in the convergence shell 101, one end of the first heat pipe 201 is located above the trumpet convergence port 109, and the first heat pipes 201 are arranged in a fan shape. The other end of the first heat pipe 201 extends out of the convergence shell 101 and is provided with and welded with a first heat exchange plate group 202. The cold water pipe 601 passes through the first heat exchange plate group 202 and is provided therewith. The trumpet convergence port 109 can converge the flue gas on the one hand, and can also slow down the speed of the flue gas passing through the trumpet convergence port 109, prolonging the time for the flue gas to pass through the first heat pipe 201, further improving the absorption of the flue gas heat by the first heat pipe 201, and then improving the recovery of the heat in the flue gas.

[0022] The exhaust heat recovery chamber 104 is installed on the convergent shell 101. Fig.13 As shown, a plurality of exhaust heat recovery control devices 300 are installed in the exhaust heat recovery chamber 104, and an exhaust pipe 106 is connected to the upper end of the exhaust heat recovery chamber 104 through a collecting shell 105, and the exhaust pipe 106 is connected to a smoke exhaust pipe reserved on the building.

[0023] The exhaust heat recovery control device 300 includes a first mounting plate 305 and a second mounting plate 306. The first mounting plate 305 and the second mounting plate 306 are arranged in parallel. The first mounting plate 305 is located above the second mounting plate 306. A rotating shaft 301 is installed at one end of the first mounting plate 305. Two baffles 302 arranged opposite to each other are installed on the rotating shaft 301. A card slot 304 is provided on the first mounting plate 305. The baffle 302 is engaged with the card slot 304. The card slot 304 is located above the first mounting plate 305. A partition 107 is installed in the exhaust heat recovery chamber 104. A limiting plate 303 is provided on one side of the partition 107. When the smoke flows from bottom to top, the smoke will push the baffle 302 on one side of the rotating shaft against the limiting plate 303, and the baffle 302 on the other side of the rotating shaft will be stuck in the card slot 304, which can prevent smoke leakage (refer to Fig. 9 ).

[0024] A protective pad 103 is installed in the convergence groove 102, and a servo 308 is inlaid and installed on the protective pad 103. The protective pad 103 is made of high-temperature resistant silicone material. The servo 308 drives the corresponding rotating shaft 301 to rotate 90 degrees clockwise or 90 degrees counterclockwise through the connecting rod mechanism 307. A plurality of second heat pipes 203 are installed between the first mounting plate 305 and the second mounting plate 306. One end of the second heat pipe 203 extends out of the exhaust gas heat recovery chamber 104 and is welded to the first heat exchange plate group 202. The servo 308 has the characteristics of high temperature and explosion resistance and is suitable for gas environment.

[0025] A fast-pass opening 309 is formed between the first mounting plate 305 and the limiting plate 303 , a slow-pass opening 310 is formed between one end of the first mounting plate 305 and the exhaust gas heat recovery chamber 104 , a flue gas inlet 311 is provided between one end of the second mounting plate 306 and the partition 107 , and a plurality of temperature sensors 110 are installed in the exhaust gas heat recovery chamber 104 .

[0026] When the present embodiment is used, after the smoke is generated, it is guided by the air guide plate 108 and enters the interior of the convergence shell 101. After the smoke is converged by the horn convergence port 109, it enters the upper side of the horn convergence port 109. At this time, the smoke is fan-shaped and the fan-shaped divergent smoke can perform better heat exchange with the fan-shaped first heat pipe 201, thereby increasing the heat absorbed by the first heat pipe 201 per unit time. After the flue gas passes through the convergent shell 101 and enters the exhaust gas heat recovery chamber 104, the temperature of the flue gas passing through the flue gas inlet 311 is verified by the temperature sensor 110; When the temperature is higher than the set temperature (70 degrees Celsius in this embodiment), refer to Fig. 9 and Fig.11, the steering gear 308 controls the rotation of 301, and the baffle 302 closes the fast-pass port 309, so that the smoke first passes through the smoke inlet 311 on the side of the second mounting plate 306, and passes through the slow-pass port 310 on the side of the first mounting plate 305, so that the smoke contacts the second heat pipe 203 between the first mounting plate 305 and the second mounting plate 306, and the residual heat of the smoke is absorbed by the second heat pipe 203, which greatly improves the absorption of the residual heat in the smoke by the second heat pipe 203; When the temperature is lower than or equal to the set temperature (70 degrees Celsius in this embodiment), refer to Fig.10 and Fig.11 The steering gear 308 controls the rotation of 301, and the baffle 302 closes the passage between the first mounting plate 305 and the second mounting plate 306, so that the smoke can be directly discharged through the smoke inlet 311 and the quick-pass port 309 through the exhaust pipe 106, thereby preventing the smoke temperature from being too low and forming small water droplets of condensation in the collection shell 105 and the exhaust pipe 106, thereby improving the safety of the water heater.

[0027] In the second embodiment of the present invention, a plurality of heat absorbing fins 312 are installed on the second heat pipe 203. When a plurality of exhaust gas heat recovery control devices 300 are arranged in cooperation, the number of heat absorbing fins 312 on the second heat pipe 203 in each exhaust gas heat recovery control device 300 can be adjusted. The more the number of heat absorbing fins 312, the stronger the heat exchange efficiency of the second heat pipe 203 between the corresponding first mounting plate 305 and the second mounting plate 306. The fewer the number of heat absorbing fins 312, the weaker the heat exchange efficiency of the second heat pipe 203 between the corresponding first mounting plate 305 and the second mounting plate 306.

[0028] Reference Fig.15 (The figure consists of two exhaust gas heat recovery control devices 300), there are four (two groups) second heat pipes 203 with different numbers of heat absorbing fins 312 installed in the figure, the number of heat absorbing fins 312 on the upper second heat pipe 203 is larger, and the number of heat absorbing fins 312 on the lower second heat pipe 203 is smaller, and the heat absorbing capacity of the upper second heat pipe 203 is greater than that of the lower second heat pipe 203; Then, when the flue gas with a temperature of 70 degrees Celsius enters the exhaust heat recovery chamber 104, after the flue gas with a temperature of 70 degrees Celsius passes through the exhaust heat recovery control device 300 above, the second heat pipe 203 absorbs more heat due to the large number of heat absorbing fins 312 on the second heat pipe 203, so that the exhaust flue gas temperature is only 40 degrees Celsius. The flue gas temperature is relatively low at this time, and condensation is easily generated in the exhaust pipe (the pipe outside the room connected to the exhaust pipe 106), and the condensed water is easy to flow back into the water heater, causing a dangerous situation; Then, after the flue gas with a temperature of 70 degrees Celsius passes through the exhaust gas heat recovery control device 300 below, since there are fewer heat-absorbing fins 312 on the second heat pipe 203, the second heat pipe 203 absorbs less heat, so that the temperature of the exhausted flue gas is still 50 degrees Celsius, and condensation will not occur in the exhaust pipe, and it is not easy to cause danger. At this time, the exhaust gas heat recovery control device 300 below is used to recover and reuse the heat of the flue gas; From the above example (in the example, the relative humidity is 100 and the ambient temperature is 45 degrees Celsius, at which time water vapor below 45 degrees Celsius will condense into small water droplets), it can be seen that this embodiment can absorb the residual heat in the flue gas at different temperatures through different exhaust gas heat recovery control devices 300, so that the heat in the exhausted flue gas can be reused to the greatest extent, thereby improving the heat utilization efficiency of the flue gas and reducing energy loss and gas usage.

[0029] In the third embodiment of the present invention, a second heat exchange plate group 205 is welded to one end of the second heat pipe 203. The second heat exchange plate group 205 is arranged in conjunction with the hot water pipe 602. The residual heat in the flue gas is used to heat and keep the hot water in the hot water pipe 602 warm.

[0030] In the fourth embodiment of the present invention, referring to Figure 1 and Figure 2 A plurality of third heat pipes 204 are installed between the first mounting plate 305 and the second mounting plate 306. One end of the third heat pipe 204 extends out of the exhaust gas heat recovery chamber 104 and is provided with a second heat exchange plate group 205. The second heat pipe 203 and the third heat pipe 204 are respectively arranged on both sides of the exhaust gas heat recovery chamber 104. The cold water in the cold water pipe 601 is heated by the second heat pipe 203 on one side, and the hot water in the hot water pipe 602 is heated and kept warm by the third heat pipe 204 on the other side.

[0031] In this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or apparatus.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat exchanger for recovering waste heat from flue gas of a gas water heater, comprising a heat exchange chamber (603), a combustion chamber (604), a gas combustion tank (605), and an air intake fan (606) which are installed in sequence from top to bottom; a heat exchange coil (607) is provided in the heat exchange chamber (603), and a cold water pipe (601) and a hot water pipe (602) are respectively installed at both ends of the heat exchange coil (607), characterized in that: Also includes: A focusing shell (101), the focusing shell (101) being located above the heat exchange chamber (603), an air guide plate (108) being provided inside the focusing shell (101), the air guide plate (108) being in an arc shape, a focusing groove (102) being provided on the focusing shell (101), and a horn focusing opening (109) being formed on the focusing shell (101); A plurality of first heat pipes (201), wherein the first heat pipes (201) are mounted in cooperation with the interior of a convergence shell (101), one end of the first heat pipes (201) is located above the horn convergence port (109), the first heat pipes (201) are arranged in a fan shape, the other end of the first heat pipes (201) extends out of the convergence shell (101) and is provided with and mounted in cooperation with a first heat exchange plate group (202), and the cold water pipe (601) passes through the first heat exchange plate group (202) and is provided in cooperation with it.

2. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 1, characterized in that: The convergence shell (101) is equipped with an exhaust gas heat recovery chamber (104), and a plurality of exhaust gas heat recovery control devices (300) are equipped in the exhaust gas heat recovery chamber (104). The upper end of the exhaust gas heat recovery chamber (104) is connected to an exhaust pipe (106) via a collection shell (105).

3. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 2, characterized in that: The exhaust gas heat recovery control device (300) comprises a first mounting plate (305) and a second mounting plate (306), wherein the first mounting plate (305) and the second mounting plate (306) are arranged in parallel, and the first mounting plate (305) is located above the second mounting plate (306).

4. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 3, characterized in that: A rotating shaft (301) is mounted on one end of the first mounting plate (305), and two baffles (302) arranged opposite to each other are mounted on the rotating shaft (301).

5. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 4, characterized in that: The first mounting plate (305) is provided with a slot (304), and the baffle plate (302) is snap-fitted with the slot (304).

6. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 4, characterized in that: A partition plate (107) is installed in the exhaust gas heat recovery chamber (104), and a limiting plate (303) is provided on one side of the partition plate (107).

7. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 6, characterized in that: A quick-pass opening (309) is formed between the first mounting plate (305) and the limiting plate (303), a slow-pass opening (310) is formed between one end of the first mounting plate (305) and the exhaust gas heat recovery chamber (104), and a smoke inlet (311) is provided between one end of the second mounting plate (306) and the partition plate (107).

8. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 4, characterized in that: A protective pad (103) is installed in the convergence groove (102), a steering gear (308) is embedded and installed on the protective pad (103), and the steering gear (308) is driven and connected to the corresponding rotating shaft (301) through a connecting rod mechanism (307).

9. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 8, characterized in that: A plurality of second heat pipes (203) are mounted between the first mounting plate (305) and the second mounting plate (306); one end of the second heat pipe (203) extends out of the exhaust gas heat recovery chamber (104) and is arranged in cooperation with the first heat exchange plate group (202).

10. The heat exchanger for recovering waste heat from flue gas of a gas water heater according to claim 8, characterized in that: A plurality of third heat pipes (204) are installed between the first installation plate (305) and the second installation plate (306); one end of the third heat pipe (204) extends out of the exhaust gas heat recovery chamber (104) and is provided with and installed with a second heat exchange plate group (205); and a plurality of temperature sensors (110) are installed in the exhaust gas heat recovery chamber (104).

Images