Condensing heat exchanger and gas water heater

Abstract

The application discloses a condensing heat exchanger and a gas water heater, the condensing heat exchanger comprises a shell, the shell comprises a shell body and a gas cavity arranged in the shell body, a smoke inlet is formed in the circumferential side of the shell body, a smoke outlet is formed in the upper side of the shell body, and a water outlet is formed in the lower side of the shell body, the smoke inlet, the smoke outlet and the water outlet are communicated with the gas cavity; a condensate water path structure is installed in the shell; a first liquid seal plate is arranged in the gas cavity and located between the smoke inlet and the condensate water path structure, a first smoke inlet area is arranged on the upper portion of the first liquid seal plate, a second smoke inlet area is arranged on the lower portion of the first liquid seal plate, a first smoke inlet hole is formed in the first smoke inlet area, a second smoke inlet hole is formed in the second smoke inlet area, and the equivalent area of the first smoke inlet hole is equivalent to the equivalent area corresponding to the smoke concentration C required by the national standard when the gas water heater is combusted at the maximum load.

Description

Technical Field

[0001] This invention relates to the field of home appliance technology, and in particular to a condensing heat exchanger and a gas water heater. Background Technology

[0002] To improve heat exchange efficiency, existing gas water heaters typically include a condensing heat exchanger on one side of the main heat exchanger to further heat the high-temperature flue gas discharged from the main heat exchanger. However, condensate produced by the condensing heat exchanger can easily enter the main heat exchanger when the drain channel is blocked. Therefore, current technology generally uses a water level sensor to detect the condensate level, triggering an alarm and stopping the gas water heater when the level reaches a warning line to ensure safety. However, water level sensors are prone to failure in actual use, leading to unstable detection results and increasing the risk of safety accidents involving gas water heaters.

[0003] Therefore, there is an urgent need for a gas water heater to solve the above problems. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the problems existing in the prior art. To this end, the present invention proposes a condensing heat exchanger that can effectively and stably detect the condensate water level and prevent condensate water from entering the main heat exchanger of the gas water heater.

[0005] The above objectives are achieved through the following technical solutions:

[0006] A condensing heat exchanger, comprising:

[0007] The outer casing includes an outer casing body and an air cavity disposed within the outer casing body. A smoke inlet is provided on the periphery of the outer casing body, a smoke outlet is provided on the upper side of the outer casing body, and a water outlet is provided on the lower side of the outer casing body. The smoke inlet, the smoke outlet, and the water outlet are all connected to the air cavity.

[0008] A condensate drainage system is installed inside the outer casing;

[0009] A first liquid seal plate is disposed within the gas cavity and located between the flue gas inlet and the condensate water circuit structure. A first flue gas inlet area is provided on the upper part of the first liquid seal plate, and a second flue gas inlet area is provided on the lower part of the first liquid seal plate. A first flue gas inlet hole is provided in the first flue gas inlet area, and a second flue gas inlet hole is provided in the second flue gas inlet area. The sum of the areas of the first flue gas inlet hole and the second flue gas inlet hole is greater than the area of ​​the flue gas inlet. The equivalent area of ​​the first flue gas inlet hole is the equivalent area corresponding to the flue gas concentration C required by the national standard when the gas water heater is burning at maximum load.

[0010] Optionally, the condensate water circuit structure includes:

[0011] Multiple sets of water pipe assemblies, wherein the first liquid seal plate is located between the flue inlet and the multiple sets of water pipe assemblies;

[0012] The first water channel adapter plate includes a first water channel plate body and a plurality of first adapter water channels disposed on the first water channel plate body, and two adjacent groups of the water pipe assemblies are connected through one of the first adapter water channels.

[0013] The second water channel adapter plate includes a second water channel plate body and a plurality of second adapter water channels disposed on the second water channel plate body. Two adjacent sets of water pipe assemblies are connected through one of the second adapter water channels.

[0014] Optionally, each of the two opposite ends of the outer casing body is provided with an opening, the first water channel plate body is disposed at one of the openings and is sealed to the outer casing body, the second water channel plate body is disposed at the other opening and is sealed to the outer casing body, and the outer casing body, the first water channel plate body, and the second water channel plate body enclose the air cavity.

[0015] Optionally, the bottom side of the outer casing body is provided with a downwardly recessed flow guide groove, and the water outlet is opened in the flow guide groove.

[0016] Optionally, it also includes a liquid seal structure, the liquid seal structure comprising:

[0017] A liquid seal box has a cavity inside. The upper part of the liquid seal box has an inlet hole that connects the outlet to the cavity, and the lower part of the liquid seal box has an outlet hole that connects the drainage structure to the cavity.

[0018] A second liquid seal plate is disposed in the cavity. The upper end of the second liquid seal plate is connected to the upper side plate of the liquid seal box, and there is a water inlet gap between the lower end of the second liquid seal plate and the lower side plate of the liquid seal box.

[0019] A third liquid seal plate is disposed in the cavity at a distance from the second liquid seal plate. The lower end of the third liquid seal plate is connected to the lower side plate of the liquid seal box. There is a water outlet gap between the upper end of the third liquid seal plate and the upper side plate of the liquid seal box. The water inlet is located on the side of the second liquid seal plate opposite to the third liquid seal plate, and the water outlet is located on the side of the third liquid seal plate opposite to the second liquid seal plate.

[0020] Optionally, the liquid seal structure further includes a water level detector disposed on the upper part of the cavity, the water level detector being used to detect the water level information in the cavity and transmit the water level information to the control unit of the gas water heater.

[0021] Another aspect of the present invention provides a gas water heater, including a main heat exchanger and the aforementioned condensing heat exchanger. The main heat exchanger includes a shell, a fan, and a combustion heat exchanger disposed within the shell. The shell has an air inlet and a flue gas outlet, the air inlet being connected to the flue gas outlet. The lowest point of the flue gas outlet is higher than the lowest point of the air inlet. The fan is installed at the air inlet. A cooling channel is provided between the shell and the combustion heat exchanger, one end of the cooling channel being connected to the air inlet and the other end being connected to the flue gas outlet.

[0022] Optionally, the combustion heat exchanger includes a combustion chamber disposed within the housing and a burner and heat exchanger disposed within the combustion chamber, and the air-cooling channel is located between the housing and the combustion chamber.

[0023] Optionally, the air-cooling channel includes a front air-cooling channel, a rear air-cooling channel, a left air-cooling channel, and a right air-cooling channel. The front air-cooling channel is located between the front side plate of the housing and the front side wall of the combustion chamber. The rear air-cooling channel is located between the rear side plate of the housing and the rear side wall support of the combustion chamber. The left air-cooling channel is located between the left side plate of the housing and the left side wall of the combustion chamber. The right air-cooling channel is located between the right side plate of the housing and the right side wall of the combustion chamber.

[0024] Optionally, it also includes a flue pipe, through which the flue gas outlet and the flue gas inlet are connected.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] The condensing heat exchanger provided by this invention allows flue gas to enter the condensate water circuit structure through the first and second flue gas inlets of the first liquid seal plate for heat exchange before being discharged from the flue gas outlet. When the flue gas enters the condensate water circuit structure, the high-temperature flue gas exchanges heat with the condensate water circuit. When condensate water is generated on the condensate water circuit structure, the condensate water accumulates in the gas chamber and is discharged from the outlet. When the outlet is blocked, the water level of the condensate water gradually rises, the second flue gas inlet is gradually submerged, the resistance of the gas water heater's fan gradually increases, and the fan speed gradually increases. When the water level of the condensate water rises and submerges the second flue gas inlet area, the flue gas entering the condensate water circuit structure through the first liquid seal plate decreases to a preset value (the flue gas concentration C required by national standards). At this time, the fan speed of the gas water heater also increases to the preset maximum threshold. At this time, the system stops working and performs an alarm, thereby preventing the water level of the condensate water in the gas chamber from continuing to rise and eventually causing the condensate water to flow into the combustion heat exchanger of the gas water heater. Compared to existing technologies that use liquid level sensors to detect liquid levels, this method is safer and more reliable because liquid level sensors are prone to failure in practical applications, leading to liquid level detection failure. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of the condenser heat exchanger of the water heater provided in a specific embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Exploded view;

[0029] Figure 3 This is one of the cross-sectional views of the condenser heat exchanger of the water heater provided in a specific embodiment of the present invention;

[0030] Figure 4 This is a second cross-sectional view of the condenser heat exchanger of the water heater provided in a specific embodiment of the present invention;

[0031] Figure 5 This is one of the cross-sectional views of the condenser heat exchanger of the water heater provided in a specific embodiment of the present invention;

[0032] Figure 6 This is a three-dimensional structural diagram of the condenser heat exchanger of the water heater after removing the liquid seal structure and condensate pipe according to a specific embodiment of the present invention;

[0033] Figure 7 This is a second cross-sectional view of the condenser heat exchanger of the water heater provided in a specific embodiment of the present invention.

[0034] In the picture:

[0035] 10. Condensing heat exchanger; 1. Shell; 11. Shell body; 111. Flue gas inlet; 112. Flue gas outlet; 113. Water outlet; 114. Flow guide groove; 100. Air chamber;

[0036] 20. Main heat exchanger; 2. Condensate circuit structure; 21. Water pipe assembly; 211. Water pipe; 22. First water circuit adapter plate; 221. First water circuit plate body; 222. First adapter water circuit; 23. Second water circuit adapter plate; 231. Second water circuit plate body; 232. Second adapter water circuit; 24. Inlet connector; 25. Outlet connector;

[0037] 3. First liquid seal plate; 31. First smoke inlet area; 301. First smoke inlet hole; 32. Second smoke inlet area; 302. Second smoke inlet hole;

[0038] 4. Liquid seal structure; 41. Liquid seal box; 40. Cavity; 42. Water inlet; 43. Water outlet; 44. Water level detector; 451. Second liquid seal plate; 452. Third liquid seal plate;

[0039] 5. Condensate drain pipe;

[0040] 6. Shell;

[0041] 7. Smoke pipe;

[0042] 81. Burner; 82. Heat exchanger;

[0043] 9. Fan;

[0044] 200. Combustion chamber;

[0045] 301. Front air-cooling aisle; 302. Rear air-cooling aisle; 303. Left air-cooling aisle; 304. Right air-cooling aisle. Detailed Implementation

[0046] The following embodiments illustrate the present invention, but the present invention is not limited to these embodiments. Modifications to the specific embodiments of the present invention or equivalent substitutions for some technical features, without departing from the spirit of the present invention, should all be covered within the scope of the technical solutions claimed in the present invention.

[0047] Please refer to Figures 1-7 This invention provides a condensing heat exchanger 20, comprising a shell 1, a condensate water passage structure 2, and a first liquid seal plate 3. The shell 1 includes a shell body 11 and an air cavity 100 disposed within the shell body 11. A flue gas inlet 111 is formed on the periphery of the shell body 11, a flue gas outlet 112 is formed on the upper side of the shell body 11, and a water outlet 113 is formed on the lower side of the shell body 11. The flue gas inlet 111, flue gas outlet 112, and water outlet 113 are all connected to the air cavity 100. The condensate water passage structure 2 is installed inside the shell 1. The first liquid seal plate 3 is disposed in the gas cavity 100 and located between the smoke inlet 111 and the condensate water circuit structure 2. The upper part of the first liquid seal plate 3 is provided with a first smoke inlet area 31, and the lower part of the first liquid seal plate 3 is provided with a second smoke inlet area 32. The first smoke inlet area 31 is provided with a first smoke inlet hole 301, and the second smoke inlet area 32 is provided with a second smoke inlet hole 302. The sum of the areas of the first smoke inlet hole 301 and the second smoke inlet hole 302 is greater than the area of ​​the smoke inlet 111. The equivalent area of ​​the first smoke inlet hole 301 is the equivalent area corresponding to the flue gas concentration C required by the national standard when the gas water heater is burning at maximum load.

[0048] The condenser heat exchanger 2082 provided by this invention allows flue gas to enter the condensate water passage structure 2 through the first flue gas inlet 301 and the second flue gas inlet 302 of the first liquid seal plate 3 for heat exchange before being discharged from the flue gas outlet 112. When the flue gas enters the condensate water passage structure 2, the high-temperature flue gas exchanges heat with the condensate water passage. When condensate water is generated on the condensate water passage structure 2, the condensate water accumulates in the gas chamber 100 and is discharged from the outlet 113. When the outlet 113 is blocked, the water level of the condensate water gradually rises, and the second flue gas inlet 302 is gradually submerged, thus reducing the combustion heat. As the resistance of the water heater's fan 9 gradually increases, its rotational speed also gradually increases. When the condensate water level rises and submerges the second flue gas inlet area 32, the flue gas entering the condensate water path structure 2 via the first liquid seal plate 3 decreases to a preset value (the national standard required flue gas concentration C). At this point, the rotational speed of the gas water heater's fan 9 also increases to the preset maximum threshold. The system then stops working and triggers an alarm, thus preventing the condensate water level in the gas chamber 100 from continuously rising and ultimately causing condensate water to flow into the gas water heater's combustion heat exchanger 82. Compared to the existing technology that uses a liquid level sensor to detect the liquid level, this method is safer and more reliable because, in practical applications, liquid level sensors are prone to failure, leading to liquid level detection failure.

[0049] The current national standard requires that the system must sound an alarm when the outlet 113 is blocked and the flue gas concentration reaches 2000 ppm.

[0050] Optionally, the condensate water circuit structure 2 includes multiple sets of water pipe assemblies 21, a first water circuit adapter plate 22, and a second water circuit adapter plate 23. A first liquid seal plate 3 is located between the flue gas inlet 111 and the multiple sets of water pipe assemblies 21. The first water circuit adapter plate 22 includes a first water circuit plate body 221 and multiple first adapter water circuits 222 disposed on the first water circuit plate body 221, with adjacent sets of water pipe assemblies 21 connected via a first adapter water circuit 222. The second water circuit adapter plate 23 includes a second water circuit plate body 231 and multiple second adapter water circuits 232 disposed on the second water circuit plate body 231, with adjacent sets of water pipe assemblies 21 connected via a second adapter water circuit 232.

[0051] Optionally, the condensate water circuit structure 2 also includes an inlet connector 24 and an outlet connector 25. The inlet connector 24 is connected to a first transition water circuit 222, and the outlet connector 25 is connected to another first transition water circuit 222.

[0052] Optionally, the water pipe assembly 21 includes multiple water pipes 211.

[0053] Optionally, openings are provided at both opposite ends of the outer shell body 11. The first water channel plate body 221 is located at one of the openings and is sealed to the outer shell body 11. The second water channel plate body 231 is located at the other opening and is sealed to the outer shell body 11. The outer shell body 11, the first water channel plate body 221, and the second water channel plate body 231 enclose and form an air cavity 100, which has a simple and compact structure.

[0054] Optionally, a downwardly recessed flow guide groove 114 is provided on the bottom side of the outer casing 11, and a water outlet 113 is provided in the flow guide groove 114. By providing the flow guide groove 114, the condensate on the bottom side of the outer casing 11 is guided to the water outlet 113.

[0055] Optionally, the system also includes a liquid seal structure 4, which comprises a liquid seal box 41, a second liquid seal plate 451, and a third liquid seal plate 452. The liquid seal box 41 contains a cavity 40. The upper part of the liquid seal box 41 has an inlet hole 42 connecting the outlet 113 to the cavity 40, and the lower part of the liquid seal box 41 has an outlet hole 43 connecting the drainage structure to the cavity 40. The second liquid seal plate 451 is disposed within the cavity 40. The upper end of the second liquid seal plate 451 is connected to the upper side plate of the liquid seal box 41, and a water inlet gap exists between the lower end of the second liquid seal plate 451 and the lower side plate of the liquid seal box 41. The third liquid seal plate 452 and the second liquid seal plate 451 are spaced apart within the cavity 40. The lower end of the third liquid seal plate 452 is connected to the lower side plate of the liquid seal box 41, and there is a water outlet gap between the upper end of the third liquid seal plate 452 and the upper side plate of the liquid seal box 41. The water inlet 42 is located on the side of the second liquid seal plate 451 opposite to the third liquid seal plate 452, and the water outlet 43 is located on the side of the third liquid seal plate 452 opposite to the second liquid seal plate 451. The condensate in the gas cavity 100 flows into the cavity 40 through the water outlet 113, and then flows out through the water inlet gap and the water outlet gap to the water outlet 43, and then is discharged to the drainage structure outside the gas water heater, while preventing flue gas from being discharged through the water outlet 43.

[0056] Optionally, it also includes a condensate pipe 5211, through which the outlet 113 and the inlet 42 are connected.

[0057] Optionally, the liquid seal structure 4 also includes a water level detector 44 disposed on the upper part of the cavity 40. The water level detector 44 is used to detect the water level information in the cavity 40 and transmit the water level information to the control unit of the gas water heater. Specifically, when the drainage structure is blocked, the condensate in the cavity 40 gradually rises. When the water level rises to a preset position, the water level detector 44 is activated, thereby detecting the information of the drainage structure blockage. At this time, the control unit issues an alarm.

[0058] In this embodiment, when the water level detector 44 fails, the water level in the cavity 40 will continue to rise, and the condensate will gradually accumulate in the gas cavity 100 and continue to rise. When the water level submerges the second smoke inlet area 32 of the first liquid seal plate 3, the fan speed 9 reaches the preset maximum threshold. At this time, the system stops working and performs an alarm, thereby avoiding the problem that the condensate water level in the gas cavity 100 will continue to rise and eventually cause the condensate water to flow into the combustion heat exchanger 82 of the gas water heater. This embodiment sets up a dual condensate water level detection function, which effectively reduces the problem of condensate water entering the combustion heat exchanger 82.

[0059] Another aspect of the present invention provides a gas water heater, including a main heat exchanger 1082 and the aforementioned condensing heat exchanger 2082. The main heat exchanger 1082 includes a shell 6, a fan 9, and a combustion heat exchanger 82 disposed within the shell 6. The shell 6 has an air inlet and a flue gas outlet. The flue gas inlet 111 is connected to the flue gas outlet. The lowest point of the flue gas outlet is set higher than the lowest point of the flue gas inlet 111 to prevent condensate from entering the combustion heat exchanger 82 when the condensate has not submerged the second flue gas inlet area 32. The fan 9 is installed at the air inlet. A cooling channel is provided between the shell 6 and the combustion heat exchanger 82. One end of the cooling channel is connected to the air inlet, and the other end is connected to the flue gas outlet. The fan 9 draws cold air from the outside into the cooling channel. The cold air heated in the cooling channel and the high-temperature flue gas generated by the combustion heat exchanger 82 are both flowed through the flue gas outlet to the condensing heat exchanger 2082 for further heat exchange due to the negative pressure generated by the fan 9.

[0060] Optionally, the combustion heat exchanger 82 includes a combustion chamber 200 disposed within the housing 6, and a burner 81 and a heat exchanger 82 disposed within the combustion chamber 200. An air-cooling channel is located between the housing 6 and the combustion chamber 200. The fan 9 draws in outside cold air into the air-cooling channel to cool the inner wall of the combustion chamber 200. The heated cold air is then discharged through the flue gas outlet to the condensing heat exchanger 2082 for heat exchange, thereby improving the heat exchange efficiency of the gas water heater and preventing overheating of the housing 6.

[0061] Optionally, the air-cooling channel includes a front air-cooling channel 301, a rear air-cooling channel 302, a left air-cooling channel 303, and a right air-cooling channel 304. The front air-cooling channel 301 is located between the front side plate of the housing 6 and the front side wall of the combustion chamber 200; the rear air-cooling channel 302 is located between the rear side plate of the housing 6 and the rear side wall support of the combustion chamber 200; the left air-cooling channel 303 is located between the left side plate of the housing 6 and the left side wall of the combustion chamber 200; and the right air-cooling channel 304 is located between the right side plate of the housing 6 and the right side wall of the combustion chamber 200. By setting the front air-cooling channel 301, the rear air-cooling channel 302, the left air-cooling channel 303, and the right air-cooling channel 304, uniform cooling and heat exchange of the cavity wall of the combustion chamber 200 can be achieved.

[0062] Optionally, it also includes a flue pipe 7, through which the flue gas outlet and the flue gas inlet 111 are connected. By providing the flue pipe 7, the flue gas of the main heat exchanger 1082 can be guided to the condensing heat exchanger 2082.

[0063] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A condensing heat exchanger, characterized in that, include: The outer shell (1) includes an outer shell body (11) and an air cavity (100) disposed within the outer shell body (11). A smoke inlet (111) is provided on the periphery of the outer shell body (11), a smoke outlet (112) is provided on the upper side of the outer shell body (11), and a water outlet (113) is provided on the lower side of the outer shell body (11). The smoke inlet (111), the smoke outlet (112), and the water outlet (113) are all connected to the air cavity (100). The condensate drainage structure (2) is installed inside the outer casing (1); A first liquid seal plate (3) is disposed in the gas cavity (100) and located between the smoke inlet (111) and the condensate water circuit structure (2). A first smoke inlet area (31) is provided on the upper part of the first liquid seal plate (3), and a second smoke inlet area (32) is provided on the lower part of the first liquid seal plate (3). A first smoke inlet hole (301) is provided on the first smoke inlet area (31), and a second smoke inlet hole (302) is provided on the second smoke inlet area (32). The sum of the areas of the first smoke inlet hole (301) and the second smoke inlet hole (302) is greater than the area of ​​the smoke inlet (111). The equivalent area of ​​the first smoke inlet hole (301) is the equivalent area corresponding to the flue gas concentration C required by the national standard when the gas water heater is burning at maximum load.

2. The condensing heat exchanger according to claim 1, characterized in that, The condensate drainage system (2) includes: Multiple sets of water pipe assemblies (21), with the first liquid seal plate (3) located between the flue gas inlet (111) and the multiple sets of water pipe assemblies (21); The first water channel adapter plate (22) includes a first water channel plate body (221) and a plurality of first adapter water channels (222) disposed on the first water channel plate body (221). Two adjacent sets of water pipe assemblies (21) are connected through one of the first adapter water channels (222). The second water channel adapter plate (23) includes a second water channel plate body (231) and a plurality of second adapter water channels (232) disposed on the second water channel plate body (231). Two adjacent sets of water pipe assemblies (21) are connected through a second adapter water channel (232).

3. The condensing heat exchanger according to claim 2, characterized in that, The outer shell body (11) has openings at both opposite ends. The first water channel plate body (221) is disposed at one of the openings and is sealed to the outer shell body (11). The second water channel plate body (231) is disposed at the other opening and is sealed to the outer shell body (11). The outer shell body (11), the first water channel plate body (221), and the second water channel plate body (231) enclose the air cavity (100).

4. The condensing heat exchanger according to claim 1, characterized in that, The bottom side of the outer shell body (11) is provided with a downwardly recessed flow guide groove (114), and the water outlet (113) is opened in the flow guide groove (114).

5. The condensing heat exchanger according to any one of claims 1-4, characterized in that, It also includes a liquid seal structure (4), which comprises: A liquid seal box (41) is provided with a cavity (40) inside. The upper part of the liquid seal box (41) is provided with a water inlet (42) that connects the water outlet (113) and the cavity (40), and the lower part of the liquid seal box (41) is provided with a water outlet (43) that connects the drainage structure and the cavity (40). A second liquid seal plate (451) is disposed in the cavity (40). The upper end of the second liquid seal plate (451) is connected to the upper side plate of the liquid seal box (41), and there is a water inlet gap (4510) between the lower end of the second liquid seal plate (451) and the lower side plate of the liquid seal box (41). The third liquid seal plate (452) is disposed in the cavity (40) at a distance from the second liquid seal plate (451). The lower end of the third liquid seal plate (452) is connected to the lower side plate of the liquid seal box (41). The upper end of the third liquid seal plate (452) has a water outlet gap (4520) between it and the upper side plate of the liquid seal box (41). The water inlet (42) is located on the side of the second liquid seal plate (451) away from the third liquid seal plate (452). The water outlet (43) is located on the side of the third liquid seal plate (452) away from the second liquid seal plate (451).

6. The condensing heat exchanger according to claim 5, characterized in that, The liquid seal structure (4) also includes a water level detector (44) disposed on the upper part of the cavity (40). The water level detector (44) is used to detect the water level information in the cavity (40) and transmit the water level information to the control unit of the gas water heater.

7. A gas water heater, comprising a main heat exchanger (10) and a condensing heat exchanger (20) as described in any one of claims 1-6, wherein the main heat exchanger (10) comprises a shell (6), a fan (9) and a combustion heat exchanger disposed within the shell (6), wherein the shell (6) is provided with an air inlet and a flue gas outlet, the flue gas inlet (111) is connected to the flue gas outlet, the lowest point of the flue gas outlet is higher than the lowest point of the flue gas inlet (111), the fan (9) is installed at the air inlet, and an air-cooling channel is provided between the shell (6) and the combustion heat exchanger, one end of the air-cooling channel is connected to the air inlet and the other end is connected to the flue gas outlet.

8. The gas water heater according to claim 7, characterized in that, The combustion heat exchanger includes a combustion chamber (200) disposed in the housing (6) and a burner (81) and a heat exchanger (82) disposed in the combustion chamber (200). The air-cooling channel is located between the housing (6) and the combustion chamber (200).

9. The gas water heater according to claim 8, characterized in that, The air-cooling channels include a front air-cooling channel (301), a rear air-cooling channel (302), a left air-cooling channel (303), and a right air-cooling channel (304). The front air-cooling channel (301) is located between the front side plate of the housing (6) and the front side wall of the combustion chamber (200). The rear air-cooling channel (302) is located between the rear side plate of the housing (6) and the rear side wall support of the combustion chamber (200). The left air-cooling channel (303) is located between the left side plate of the housing (6) and the left side wall of the combustion chamber (200). The right air-cooling channel (304) is located between the right side plate of the housing (6) and the right side wall of the combustion chamber (200).

10. The gas water heater according to claim 7, characterized in that, It also includes a flue (7), through which the flue gas outlet and the flue gas inlet (111) are connected.

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