Control method of gas water heater and gas water heater

Abstract

The present application relates to the technical field of water heaters, and discloses a control method of a gas water heater and the gas water heater. The gas water heater comprises a main heat exchanger, a condensing heat exchanger, a water inlet main pipe and an atomizer. The condensing heat exchanger has a water collecting cavity for collecting condensed water. The atomizer is used for atomizing the condensed water. The water inlet main pipe, the condensing heat exchanger and the main heat exchanger are sequentially communicated to form a water inlet waterway. When the real-time liquid level of the condensed water is greater than a preset liquid level threshold, the output load of the burner in the main heat exchanger is reduced. In this way, the gas water heater can reduce the generation amount of the condensed water when the condensing heat exchanger keeps working, reduce the situation that the condensed water liquid level reaches a dangerous liquid level, reduce the risk that the condensed water liquid level reaches the dangerous liquid level and triggers the shutdown of the gas water heater. Compared with stopping the work of the condensing heat exchanger to prevent the condensed water liquid level from rising, the condensing heat exchanger does not need to stop working and can continuously recover the heat in the high-temperature flue gas, so that the decline range of the thermal efficiency of the gas water heater can be reduced.

Description

Technical Field

[0001] This invention relates to the field of water heater technology, and more particularly to a control method for a gas water heater and a gas water heater. Background Technology

[0002] In the water heater with a condensing heat exchanger disclosed in existing patent document (CN120868618A), the water circuit switching component connects the inlet main pipe, the condensing heat exchanger, and the main heat exchanger sequentially in the first operating mode to form a first flow path. In the second operating mode, the water circuit switching component connects the inlet main pipe to the main heat exchanger to form a second flow path, and disconnects the inlet and / or outlet of the condensing heat exchanger from the second flow path. When the water circuit switching component operates in the first operating mode, the condensing heat exchanger works normally and produces condensate. When the liquid level in the water collection chamber reaches a first preset level, the atomization module is activated to atomize the condensate in the water collection chamber and discharge it through the flue gas outlet. When the liquid level in the water collection chamber reaches a second preset level, posing a risk of backflow into the main heat exchanger and triggering a shutdown, the water circuit switching component switches to the second operating mode. The condensing heat exchanger stops producing condensate, and the flue gas temperature increases, which helps to atomize and discharge the residual condensate in the water collection chamber, reducing the liquid level in the water collection chamber and ensuring combustion safety.

[0003] In the water heater disclosed in the aforementioned patent documents, when the liquid level in the water collection chamber reaches the second preset level and there is a risk of backflow triggering shutdown, it directly switches to the second working mode. The condensing heat exchanger stops heat exchange and no longer recovers the latent heat of vaporization in the flue gas, resulting in a significant reduction in the thermal efficiency of the gas water heater. Summary of the Invention

[0004] One of the technical problems solved by this invention is to provide a control method for a gas water heater that can reduce the amount of condensate generated and lower the risk of the gas water heater shutting down when the condenser heat exchanger is in operation.

[0005] The second technical problem solved by this invention is to provide a gas water heater that can reduce the amount of condensate generated when the condenser heat exchanger is in operation, thereby reducing the risk of the gas water heater shutting down when the condensate level reaches a dangerous level.

[0006] The first technical problem mentioned above is solved by the following technical solution: A control method for a gas water heater, the gas water heater comprising a main heat exchanger, a condensing heat exchanger, a main inlet pipe, and an atomizer, wherein the condensing heat exchanger has a water collection chamber for collecting condensate produced by the condensing heat exchanger, and the atomizer is used to atomize the condensate; the main inlet pipe, the condensing heat exchanger, and the main heat exchanger are sequentially connected to form an inlet water circuit, and the control method includes: After the gas water heater is in operation, the real-time liquid level of the condensate in the water collection chamber is obtained; Determine whether the real-time liquid level is greater than a preset liquid level threshold; If so, reduce the output load of the burner in the main heat exchanger to reduce the amount of condensate generated.

[0007] The control method for gas water heaters described in this invention has the following advantages compared to the prior art: During the operation of the gas water heater, the real-time liquid level of condensate in the water collection chamber is obtained. When the real-time liquid level of condensate is greater than the preset liquid level threshold, the output load of the burner in the main heat exchanger is reduced. This allows the gas water heater to reduce the amount of condensate generated while the condensing heat exchanger is still working, causing the condensate level to drop. This reduces the chance of the condensate level reaching the danger level and lowers the risk of the gas water heater shutting down when the condensate level reaches the danger level. In addition, compared to stopping the operation of the condensing heat exchanger to prevent the condensate level from rising, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater.

[0008] The second technical problem mentioned above is solved by the following technical solution: A gas water heater includes a main heat exchanger, a condensing heat exchanger, a main inlet pipe, an atomizer, and a controller. The condensing heat exchanger has a water collection chamber for collecting condensate produced by the condensing heat exchanger. The atomizer atomizes the condensate. The main inlet pipe, the condensing heat exchanger, and the main heat exchanger are sequentially connected to form an inlet water path. The controller is communicatively connected to the main heat exchanger and is used to execute the control method of the gas water heater according to the present invention.

[0009] Compared with the prior art, the gas water heater of the present invention has the following advantages: During the operation of the gas water heater, the real-time liquid level of condensate in the water collection chamber is obtained. When the real-time liquid level of condensate is greater than the preset liquid level threshold, the output load of the burner in the main heat exchanger is reduced. This allows the gas water heater to reduce the amount of condensate generated while the condensing heat exchanger is still working, causing the condensate level to drop. This reduces the chance of the condensate level reaching the danger level and lowers the risk of the gas water heater shutting down when the condensate level reaches the danger level. In addition, compared to stopping the operation of the condensing heat exchanger to prevent the condensate level from rising, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater.

[0010] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a control method for a gas water heater provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of a gas water heater provided in an embodiment of the present invention; Figure 3 This is a flowchart of a control method for a gas water heater provided in Embodiment 2 of the present invention; Figure 4 This is a flowchart of a control method for a gas water heater provided in Embodiment 3 of the present invention; Figure 5 This is a flowchart of a control method for a gas water heater provided in Embodiment 4 of the present invention. Detailed Implementation

[0013] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0014] Example 1 Figure 1 A flowchart of a control method for a gas water heater provided in Embodiment 1 of the present invention is shown below. Figure 1 As shown, the control method of this gas water heater includes: S101. After the gas water heater starts working, obtain the real-time liquid level of condensate in the water collection chamber.

[0015] The gas water heater in this embodiment is a water heater with a condensing heat exchanger, which recovers heat from the flue gas generated by gas combustion. Figure 2As shown, a gas water heater may include a main heat exchanger 1, a condensing heat exchanger 2, a main inlet pipe 3, an atomizer 4, and a controller 5. The main heat exchanger 1 has a burner, which is the main component for combustion and heat exchange. The high-temperature flue gas generated by combustion in the main heat exchanger 1 enters the condensing heat exchanger 2 through the flue 6. The flue gas exchanges heat with the heat exchange tubes in the condensing heat exchanger 2 to achieve heat recovery from the flue gas. At the same time, condensate is generated and collected by the water collection chamber 21 in the condensing heat exchanger 2. The atomizer 4 is used to atomize the condensate in the water collection chamber 21 and discharge it into the atmosphere. The main inlet pipe 3, the condensing heat exchanger 2, and the main heat exchanger 1 are connected in sequence to form the water inlet circuit. Figure 2 The direction of the middle arrow indicates the direction of water flow. Cold water in the main inlet pipe 3 flows into the condenser heat exchanger 2, where it undergoes heat exchange and its temperature rises before flowing into the main heat exchanger 1.

[0016] After the gas water heater is working, the real-time liquid level of the condensate in the water collection chamber 21 can be detected by a liquid level gauge. The liquid level gauge can be of various forms, and this embodiment does not limit the liquid level gauge.

[0017] S102. Determine whether the real-time liquid level is greater than the preset liquid level threshold.

[0018] In this embodiment, the preset liquid level threshold can be a value lower than the danger level. The danger level can be the liquid level that triggers the gas water heater to shut down. In one example, the danger level can be the liquid level at which condensate can backflow from the flue 6 into the main heat exchanger 1. The preset liquid level threshold can be a liquid level value that is slightly lower than the danger level.

[0019] When the real-time liquid level of condensate is detected, the real-time liquid level can be compared with the preset liquid level threshold to determine whether the real-time liquid level is greater than the preset liquid level threshold. If it is, execute S103; otherwise, continue to obtain the next real-time liquid level and compare it with the preset liquid level threshold.

[0020] S103. Reduce the output load of the burner in the main heat exchanger to reduce the amount of condensate generated.

[0021] When the real-time liquid level exceeds the preset liquid level threshold, it indicates that the condensate liquid level will continue to rise and reach a dangerous level. The controller can reduce the output load of the burner in the main heat exchanger. In one embodiment, the outlet water temperature of the gas water heater can be kept constant while reducing the inlet water flow rate of the main inlet pipe 3 to reduce the output load of the burner. For example, the controller 5 controls the water flow regulating valve 31 in the main inlet pipe 3 to reduce the inlet water flow rate. The outlet water temperature of the main heat exchanger 1 (equal to the user's set temperature) remains unchanged from the cold water inlet temperature, and the required output load decreases. This allows the controller 5 to adjust the gas regulating valve of the burner in the main heat exchanger 1 to reduce the output load of the burner by reducing the inlet water flow rate. In another embodiment, the outlet water temperature of the gas water heater can also be reduced to reduce the output load of the burner while keeping the inlet water flow rate constant. For example, the controller 5 can directly adjust the gas regulating valve of the burner in the main heat exchanger 1 to directly reduce the output load of the burner.

[0022] In one optional embodiment, when the output load of the burner decreases, the outlet water temperature of the main heat exchanger is not lower than the lower limit temperature corresponding to the user-set temperature. This lower limit temperature is lower than the set temperature. For example, the difference between the set temperature and the lower limit temperature is less than or equal to 3°C, so as to reduce the impact on the user's water use caused by the excessive decrease in outlet water temperature after the output load decreases.

[0023] This embodiment reduces the output load of the burner, thereby reducing the amount of condensate generated in the condensing heat exchanger. At the same time, the condensate is atomized by the atomizer, which lowers the condensate level and reduces the risk of the condensate level continuing to rise to the danger level and triggering the gas water heater to shut down. Compared to stopping the condensing heat exchanger to prevent the condensate level from rising to the danger level, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater.

[0024] Example 2 Figure 3 A flowchart of a control method for a gas water heater provided in Embodiment 2 of the present invention is shown below. Figure 3 As shown, the control method of this gas water heater includes: S301. After the gas water heater is working, obtain the real-time liquid level of condensate in the water collection chamber.

[0025] like Figure 2The gas water heater shown has an inlet main pipe 3, a condenser heat exchanger 2, and a main heat exchanger 1 connected in sequence to form an inlet water path. The arrows indicate the direction of water flow. Cold water in the inlet main pipe 3 flows into the condenser heat exchanger 2, where its temperature rises after heat exchange. It then flows into the main heat exchanger 1. The high-temperature flue gas generated by combustion in the main heat exchanger 1 enters the condenser heat exchanger 2 through the flue 6. The flue gas exchanges heat with the heat exchange tubes in the condenser heat exchanger 2, realizing the recovery of flue gas heat. At the same time, condensate is generated and collected by the water collection chamber 21 in the condenser heat exchanger 2. The atomizer 4 is used to atomize the condensate in the water collection chamber 21 and discharge it into the atmosphere.

[0026] After the gas water heater is working, the real-time liquid level of the condensate in the water collection chamber 21 can be detected by a liquid level gauge. The liquid level gauge can be of various forms, and this embodiment does not limit the liquid level gauge.

[0027] S302. Determine whether the real-time liquid level is greater than the preset liquid level threshold.

[0028] The preset liquid level threshold can be a value lower than the danger level, where the danger level can be the liquid level that triggers the gas water heater to shut down. In one example, the danger level can be the liquid level at which condensate can backflow from the flue 6 into the main heat exchanger 1, and the preset liquid level threshold can be a liquid level value slightly lower than the danger level.

[0029] When the real-time liquid level of condensate is detected, the real-time liquid level can be compared with the preset liquid level threshold to determine whether the real-time liquid level is greater than the preset liquid level threshold. If yes, execute S303; otherwise, continue to obtain the next real-time liquid level and compare it with the preset liquid level threshold.

[0030] S303. Keep the outlet water temperature of the gas water heater constant and reduce the inlet water flow rate of the main inlet pipe to reduce the output load of the burner.

[0031] In this embodiment, the outlet water temperature of the gas water heater can be kept constant, and the output load of the burner can be reduced by decreasing the inlet flow rate of cold water.

[0032] In an optional embodiment, the current inlet flow rate of the main inlet pipe can be gradually reduced. Specifically, a target inlet flow rate is determined based on the current inlet flow rate and a preset flow rate reduction. It is then determined whether the target inlet flow rate is less than a preset lower limit. If not, the current inlet flow rate is adjusted to the target inlet flow rate, and the process returns to step S302. The flow rate reduction can be pre-configured; for example, a larger reduction can be configured when the total cold water flow rate is large, and a smaller reduction can be configured when the total cold water flow rate is small. The reduction can also be dynamically adjusted; if the liquid level continues to rise after a single flow rate reduction, the subsequent flow rate reduction can be increased.

[0033] The preset lower limit for inlet water flow is the minimum water flow rate required to meet the user's hot water needs. Inlet water flow rates below this lower limit will affect user water usage. Each time a target inlet water flow rate is determined, it is compared to the lower limit. If the target inlet water flow rate is greater than the lower limit, the controller can control the water flow regulating valve to adjust the current inlet water flow rate to the target rate and execute step S302 to check if the real-time liquid level is greater than the preset liquid level threshold. If so, it indicates that condensate generation is excessive and the condensate level has not decreased; the current inlet water flow rate can be further reduced. If not, it indicates that condensate generation has decreased and the condensate level has decreased; the adjustment of the current inlet water flow rate stops. If the target inlet water flow rate is less than or equal to the lower limit, further reducing the inlet water flow rate will affect the user's hot water usage; the controller can then control the water flow regulating valve to adjust the current inlet water flow rate to the lower limit.

[0034] This embodiment determines the minimum inlet water flow rate that lowers the condensate level by gradually reducing the inlet water flow rate. This reduces the burner's output load, decreases condensate generation, and minimizes the impact of the reduced inlet water flow rate on the user.

[0035] In another optional embodiment, the gas water heater has a preset correspondence between the inlet water flow rate and the target inlet water flow rate. The target inlet water flow rate is less than the inlet water flow rate. This correspondence can be pre-configured; for example, when the total cold water flow rate is greater than a preset value, the target inlet water flow rate is configured to be 80% of the total inlet water flow rate; when the total cold water flow rate is less than the preset value, the target inlet water flow rate is configured to be 90% of the total flow rate. Alternatively, a lookup table of different inlet water flow rate ranges and target inlet water flow rates can be configured. This lookup table determines the current inlet water flow rate range to obtain the corresponding target inlet water flow rate. The target inlet water flow rate can be determined based on the current inlet water flow rate of the main inlet pipe, and the current inlet water flow rate can be adjusted to the target inlet water flow rate to reduce the burner's output load. For example, the controller can control the water flow regulating valve to adjust the current inlet water flow rate to the target inlet water flow rate, thereby reducing the inlet water flow rate, reducing the burner's output load, and decreasing the amount of condensate generated. This embodiment directly adjusts the inlet water flow rate to the target inlet water flow rate, which can rapidly reduce the output load of the burner, reduce the amount of condensate generated in a short time, and quickly lower the condensate level.

[0036] In this embodiment, after the gas water heater starts operating, the real-time liquid level of condensate in the collection chamber is acquired. When the real-time liquid level is higher than a preset liquid level threshold, the outlet water temperature of the gas water heater is kept constant, and the current inlet flow rate of the main inlet pipe is reduced. This reduces the output load of the burner, decreases the amount of condensate generated, and lowers the condensate level. This reduces the risk of the condensate level continuing to rise to a dangerous level and triggering the water heater to shut down. Furthermore, compared to preventing the condensate level from rising to a dangerous level by stopping the condensate heat exchanger, the condensate heat exchanger does not need to stop operating and can continuously recover heat from the high-temperature flue gas, thus reducing the decrease in the thermal efficiency of the gas water heater. In addition, reducing the output load of the burner by reducing the inlet flow rate can reduce fluctuations in the outlet water temperature, keeping the outlet water temperature within the user's set temperature range, thus reducing the impact of reduced output load and outlet water temperature fluctuations on the user's water experience.

[0037] Example 3 Figure 4 A flowchart of a control method for a gas water heater provided in Embodiment 3 of the present invention is shown below. Figure 4 As shown, the control method of this gas water heater includes: S401. After the gas water heater starts working, obtain the real-time liquid level of condensate in the water collection chamber.

[0038] like Figure 2 The gas water heater shown has an inlet main pipe 3, a condenser heat exchanger 2, and a main heat exchanger 1 connected in sequence to form an inlet water path. The arrows indicate the direction of water flow. Cold water in the inlet main pipe 3 flows into the condenser heat exchanger 2, where its temperature rises after heat exchange. It then flows into the main heat exchanger 1. The high-temperature flue gas generated by combustion in the main heat exchanger 1 enters the condenser heat exchanger 2 through the flue 6. The flue gas exchanges heat with the heat exchange tubes in the condenser heat exchanger 2, realizing the recovery of flue gas heat. At the same time, condensate is generated and collected by the water collection chamber 21 in the condenser heat exchanger 2. The atomizer 4 is used to atomize the condensate in the water collection chamber 21 and discharge it into the atmosphere.

[0039] After the gas water heater is working, the real-time liquid level of the condensate in the water collection chamber 21 can be detected by a liquid level gauge. The liquid level gauge can be of various forms, and this embodiment does not limit the liquid level gauge.

[0040] S402. Determine whether the real-time liquid level is greater than the preset liquid level threshold.

[0041] The preset liquid level threshold can be a value lower than the danger level, where the danger level can be the liquid level that triggers the gas water heater to shut down. In one example, the danger level can be the liquid level at which condensate can backflow from the flue 6 into the main heat exchanger 1, and the preset liquid level threshold can be a liquid level value slightly lower than the danger level.

[0042] When the real-time liquid level of condensate is detected, the real-time liquid level can be compared with the preset liquid level threshold to determine whether the real-time liquid level is greater than the preset liquid level threshold. If it is, execute S403; otherwise, continue to obtain the next real-time liquid level and compare it with the preset liquid level threshold.

[0043] S403. Keep the inlet water flow rate of the main inlet pipe constant and reduce the outlet water temperature of the gas water heater to reduce the output load of the burner.

[0044] In this embodiment, the burner's output load can be directly reduced by adjusting the gas regulating valve while keeping the inlet water temperature and flow rate constant. When reducing the burner's output load, the outlet water temperature of the main heat exchanger will not be lower than the lower limit temperature corresponding to the user-set temperature, which is lower than the set temperature. Optionally, the difference between the set temperature and the lower limit temperature is less than or equal to 3°C to ensure that the outlet water temperature fluctuates within a reasonable range when the burner's output load is directly reduced, minimizing the impact of the reduced outlet water temperature on the user's water usage.

[0045] In one optional embodiment, the user's set temperature has an allowable range. When the outlet water temperature is within this allowable range, the impact on the user's water experience is minimal. The lower limit of the set temperature can be determined first, the inlet water temperature can be obtained, and the target output load can be calculated based on the current inlet water flow rate, inlet water temperature, and lower limit temperature. The burner can then be adjusted from the current output load to the target output load. The lower limit of the set temperature can be pre-configured in the controller.

[0046] For example, assuming the user sets the set temperature to 65℃, the user will hardly feel any temperature change when the outlet water temperature is 65℃ or 63℃. The lower limit temperature can be set to 63℃. The target output load is calculated based on the current inlet water flow rate, inlet water temperature, and lower limit temperature. This target output load is lower than the current output load calculated using the set temperature. The controller adjusts the opening of the gas regulating valve to reduce the burner from the current output load to the target output load, thereby reducing the amount of condensate generated.

[0047] This embodiment determines the lower limit temperature based on the user's set temperature, calculates the target output load based on the current inlet water flow rate, inlet water temperature, and lower limit temperature, and adjusts the gas regulating valve to reduce the burner's output load from the current output load to the target output load. This allows the burner's output load to drop rapidly, reducing the amount of condensate generated in a short time and lowering the condensate level quickly.

[0048] In another optional embodiment, the outlet water temperature can be gradually reduced within the allowable range of the set temperature to reduce the output load of the burner. Specifically, the target outlet water temperature is determined based on the set temperature and the preset temperature reduction range. It is then determined whether the target outlet water temperature is lower than the lower limit temperature. If not, the target output load is calculated based on the current inlet water flow rate, inlet water temperature, and target outlet water temperature. The opening of the gas regulating valve is adjusted to reduce the burner's output load from the current output load to the target output load. Step S402 is then executed until the real-time liquid level of the condensate is lower than the preset liquid level threshold, or the target outlet water temperature is lower than the lower limit temperature. The temperature reduction range can be pre-configured; for example, a larger reduction range is configured when the set temperature is high, and a smaller reduction range is configured when the set temperature is low. The reduction range also supports dynamic adjustment; if the liquid level continues to rise after a single reduction in the outlet water temperature, the reduction range of subsequent outlet water temperatures can be increased.

[0049] The lower limit temperature is the lower limit value of the set temperature by the user. A water outlet temperature lower than the lower limit will affect the user's water usage. Each time the water outlet temperature is determined, it is compared with the lower limit temperature. If the target water outlet temperature is higher than the lower limit temperature, the controller can control the gas regulating valve to reduce the gas supply to the burner, directly reducing the burner's output load. It then executes S402 to check if the real-time liquid level is higher than the preset liquid level threshold. If so, it indicates that condensate generation is too high and the condensate level has not dropped, so the water outlet temperature can continue to be lowered. If not, it indicates that condensate generation has already decreased and the condensate level has dropped, so the water outlet temperature reduction should stop. If the target water outlet temperature is less than or equal to the lower limit temperature, further lowering the water outlet temperature will affect the user's hot water usage. The controller can then adjust the burner's output load to the required load corresponding to the lower limit temperature.

[0050] This embodiment determines the minimum outlet water temperature that causes the condensate level to drop by gradually reducing the outlet water temperature. This reduces the burner's output load, decreases the amount of condensate generated, and minimizes the impact of the outlet water temperature drop on the user.

[0051] In this embodiment, after the gas water heater starts working, the real-time liquid level of condensate in the water collection chamber is obtained. When the real-time liquid level is greater than the preset liquid level threshold, the output load of the burner is directly reduced, thereby reducing the amount of condensate generated and lowering the condensate liquid level. This reduces the risk of the condensate liquid level continuing to rise to the danger level and triggering the water heater to shut down. Moreover, compared to preventing the condensate liquid level from rising to the danger level by stopping the operation of the condensing heat exchanger, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater. In addition, by directly reducing the output load of the burner, a stable water flow can be guaranteed within the allowable range of the set temperature, reducing the impact of water temperature fluctuations on the user's water experience.

[0052] Example 4 Figure 5 A flowchart of a control method for a gas water heater provided in Embodiment 4 of the present invention is shown below. Figure 5 As shown, the control method of this gas water heater includes: S501. After the gas water heater starts working, obtain the real-time liquid level of condensate in the water collection chamber.

[0053] like Figure 2 The gas water heater shown has an inlet main pipe 3, a condenser heat exchanger 2, and a main heat exchanger 1 connected in sequence to form an inlet water path. The arrows indicate the direction of water flow. Cold water in the inlet main pipe 3 flows into the condenser heat exchanger 2, where its temperature rises after heat exchange. It then flows into the main heat exchanger 1. The high-temperature flue gas generated by combustion in the main heat exchanger 1 enters the condenser heat exchanger 2 through the flue 6. The flue gas exchanges heat with the heat exchange tubes in the condenser heat exchanger 2, realizing the recovery of flue gas heat. At the same time, condensate is generated and collected by the water collection chamber 21 in the condenser heat exchanger 2. The atomizer 4 is used to atomize the condensate in the water collection chamber 21 and discharge it into the atmosphere.

[0054] After the gas water heater is working, the real-time liquid level of the condensate in the water collection chamber 21 can be detected by a liquid level gauge. The liquid level gauge can be of various forms, and this embodiment does not limit the liquid level gauge.

[0055] S502. Determine whether the real-time liquid level is greater than the preset liquid level threshold.

[0056] The preset liquid level threshold can be a value lower than the danger level, where the danger level can be the liquid level that triggers the gas water heater to shut down. In one example, the danger level can be the liquid level at which condensate can backflow from the flue 6 into the main heat exchanger 1, and the preset liquid level threshold can be a liquid level value slightly lower than the danger level.

[0057] When the real-time liquid level of condensate is detected, the real-time liquid level can be compared with the preset liquid level threshold to determine whether the real-time liquid level is greater than the preset liquid level threshold. If yes, execute S503; otherwise, continue to obtain the next real-time liquid level and compare it with the preset liquid level threshold.

[0058] S503: Obtain the current inlet water flow rate and the current output load of the burner.

[0059] In this embodiment, a water flow meter can be installed in the main water inlet pipe 3 to detect the current water inlet flow rate. The current combustion load can be the output load calculated by the current water inlet flow rate, water inlet temperature and set temperature.

[0060] S504. If the current inlet water flow rate is greater than or equal to the preset flow rate threshold, the first load reduction method is used to reduce the output load of the burner.

[0061] S505. If the current inlet water flow rate is less than the preset flow rate threshold and the current output load is greater than or equal to the preset load threshold, the first load reduction method is used to reduce the output load of the burner.

[0062] S506. If the current inlet water flow rate is less than the preset flow rate threshold and the current output load is less than the preset load threshold, the second load reduction method shall be adopted to reduce the output load of the burner.

[0063] In this embodiment, the methods for reducing the output load of the burner include a first load reduction method and a second load reduction method. The first load reduction method is to keep the outlet water temperature of the gas water heater constant and reduce the inlet water flow rate of the main inlet pipe to reduce the output load of the burner. The second load reduction method is to keep the inlet water flow rate of the main inlet pipe constant and reduce the outlet water temperature of the gas water heater to reduce the output load of the burner. The gas water heater can select the appropriate method to reduce the output load under different operating conditions.

[0064] Specifically, the operating condition of the gas water heater can be determined based on the current inlet water flow and the current output load to select an appropriate method to reduce the output load. For example, the preset flow threshold can be 6L / min, and the preset load threshold can be 60% of the rated load. If the current inlet water flow is ≥6L / min, the first load reduction method is preferentially selected to reduce the output load, so as to keep the outlet water temperature of the gas water heater unchanged and reduce the output load of the burner by reducing the current inlet water flow. If the current inlet water flow is <6L / min, and the current output load is ≥60% of the rated load, the first load reduction method is preferentially selected to reduce the output load, so as to keep the outlet water temperature of the gas water heater unchanged and reduce the output load of the burner by reducing the current inlet water flow. If the current inlet water flow is <6L / min, and the current output load is <60% of the rated load, the second load reduction method is preferentially selected to reduce the output load, keeping the inlet water flow of the main inlet pipe unchanged and reducing the outlet water temperature of the gas water heater to reduce the output load of the burner. The above two methods of reducing output load can be referred to in Embodiments 2 and 3, and will not be described in detail here.

[0065] It should be noted that in Examples 1, 2, 3, and 4, if the real-time liquid level is still greater than the preset liquid level threshold within a preset time after reducing the output load of the burner in the main heat exchanger, it indicates that reducing the output load cannot effectively reduce the condensate level. This can control the gas water heater to shut down, reduce the risk of the gas water heater shutting down due to the condensate level continuously rising to a dangerous level, and improve the safety performance of the gas water heater.

[0066] In this embodiment, after the gas water heater starts working, the real-time liquid level of condensate in the water collection chamber is obtained. When the real-time liquid level is greater than the preset liquid level threshold, the current inlet water flow rate and the current output load of the burner are obtained. Based on the current inlet water flow rate and the current output load, the method of reducing the output load of the burner is determined. On the one hand, different load reduction methods can be selected based on the current inlet water flow rate, the current output load, and other operating conditions. That is, depending on different operating conditions, it is preferable to reduce the output load of the burner by keeping the outlet water temperature or the outlet water flow rate unchanged. The method of reducing the output load is more flexible and can adapt to different operating conditions. On the other hand, as the output load of the burner decreases, the amount of condensate generated decreases, and the condensate liquid level decreases, reducing the risk that the condensate liquid level will continue to rise to the dangerous level and trigger the water heater to shut down. Moreover, compared to preventing the condensate liquid level from rising to the dangerous level by stopping the operation of the condensing heat exchanger, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater.

[0067] Example 5 Figure 2 This is a schematic diagram of the structure of a gas water heater provided in Embodiment 5 of the present invention. Figure 2 As shown, the gas water heater includes a main heat exchanger 1, a condenser heat exchanger 2, a main inlet pipe 3, an atomizer 4, and a controller 5. The condenser heat exchanger 2 has a water collection chamber 21 for collecting the condensate produced by the condenser heat exchanger 2. The atomizer 4 is used to atomize the condensate. The main inlet pipe 3, the condenser heat exchanger 2, and the main heat exchanger 1 are connected in sequence to form an inlet water circuit. The controller 5 is communicatively connected to the main heat exchanger 1. The controller 5 is used to execute the control method of the gas water heater in any of the embodiments of Example 1 to Example 4.

[0068] Of course, gas water heaters can also include various types of level gauges, gas regulating valves, water flow regulating valves, inlet water temperature sensors, outlet water temperature sensors, etc.

[0069] Controller 5 can be a variety of general-purpose and / or dedicated processing components with processing and computing capabilities. Some examples of controller 5 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, microcontroller, etc. Controller 5 performs the various methods and processes described above, such as the control methods for a gas water heater.

[0070] In some embodiments, the control method for the gas water heater may be implemented as a computer program tangibly contained in a computer-readable storage medium, which, when loaded and executed by the controller 5, can perform one or more steps of the control method for the gas water heater described above. Alternatively, in other embodiments, the controller 5 may be configured to perform the control method for the gas water heater by any other suitable means (e.g., by means of firmware).

[0071] In this embodiment, during the operation of the gas water heater, the real-time liquid level of condensate in the water collection chamber is obtained. When the real-time liquid level of condensate is greater than a preset liquid level threshold, the output load of the burner in the main heat exchanger is reduced, thereby reducing the amount of condensate generated. This allows the gas water heater to reduce the amount of condensate generated while the condensing heat exchanger is still working, causing the condensate level to drop. This reduces the possibility of the condensate level reaching a dangerous level and lowers the risk of the gas water heater shutting down when the condensate level reaches a dangerous level. In addition, compared to stopping the operation of the condensing heat exchanger to prevent the condensate level from rising, the condensing heat exchanger does not need to stop working and can continuously recover heat from the high-temperature flue gas, which can reduce the decrease in the thermal efficiency of the gas water heater.

[0072] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this invention does not impose any limitations on them.

[0073] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a gas water heater, characterized in that, The gas water heater includes a main heat exchanger (1), a condenser heat exchanger (2), a main inlet pipe (3), and an atomizer (4). The condenser heat exchanger (2) has a water collection chamber (21) for collecting the condensate produced by the condenser heat exchanger (2), and the atomizer (4) is used to atomize the condensate. The main inlet pipe (3), the condenser heat exchanger (2), and the main heat exchanger (1) are connected in sequence to form an inlet water circuit. The control method includes: After the gas water heater is in operation, the real-time liquid level of the condensate in the water collection chamber is obtained; Determine whether the real-time liquid level is greater than a preset liquid level threshold; If so, reduce the output load of the burner in the main heat exchanger to reduce the amount of condensate generated.

2. The control method according to claim 1, characterized in that, When the output load of the burner in the main heat exchanger is reduced, the outlet water temperature of the gas water heater shall not be lower than the lower limit temperature corresponding to the user-set temperature; wherein the lower limit temperature is lower than the set temperature.

3. The control method according to claim 2, characterized in that, The difference between the set temperature and the lower limit temperature is less than or equal to 3°C.

4. The control method according to claim 2, characterized in that, Reducing the output load of the burner in the main heat exchanger includes: To reduce the output load of the burner, the water flow rate in the main inlet pipe is reduced while maintaining the outlet water temperature of the gas water heater; or... Keep the inlet water flow rate of the main inlet pipe constant, and reduce the outlet water temperature of the gas water heater to reduce the output load of the burner.

5. The control method according to claim 4, characterized in that, Maintaining a constant outlet water temperature for the gas water heater and reducing the inlet flow rate of the main inlet pipe to reduce the output load of the burner includes: The target inlet flow rate is determined based on the current inlet flow rate of the main inlet pipe and the preset flow rate reduction. Determine whether the target influent flow rate is less than the preset lower limit of the influent flow rate; If not, adjust the current inlet water flow rate to the target inlet water flow rate to reduce the output load of the burner, and return to the step of determining whether the real-time liquid level is greater than the preset liquid level threshold.

6. The control method according to claim 4, characterized in that, The gas water heater has a preset correspondence between the inlet water flow rate and the target inlet water flow rate, wherein the target inlet water flow rate is less than the inlet water flow rate; maintaining the outlet water temperature of the gas water heater constant while reducing the inlet water flow rate of the main inlet pipe to reduce the output load of the burner includes: Based on the current inflow rate of the main inflow pipe, determine the corresponding target inflow rate; The current inlet water flow rate is adjusted to the target inlet water flow rate to reduce the output load of the burner.

7. The control method according to claim 4, characterized in that, Maintaining a constant inlet flow rate in the main inlet pipe while reducing the outlet water temperature of the gas water heater to decrease the burner's output load includes: Based on the set temperature, determine the corresponding lower limit temperature; Obtain the inlet water temperature; The target output load is calculated based on the current inlet flow rate, inlet temperature, and lower limit temperature of the main inlet pipe. Adjust the burner from the current output load to the target output load.

8. The control method according to claim 4, characterized in that, Directly reducing the output load of the burner includes: The target outlet water temperature is determined based on the set temperature and the preset temperature drop. Determine whether the target effluent temperature is lower than the lower limit temperature; If not, calculate the target output load based on the current inlet flow rate, inlet temperature, and the target outlet temperature; Adjust the burner from the current output load to the target output load, and return to the step of determining whether the real-time liquid level is greater than the preset liquid level threshold.

9. The control method according to claim 2, characterized in that, The gas water heater is preset with a first load reduction mode and a second load reduction mode; the first load reduction mode is to keep the outlet water temperature of the gas water heater constant and reduce the inlet water flow of the main inlet pipe to reduce the output load of the burner; the second load reduction mode is to keep the inlet water flow of the main inlet pipe constant and reduce the outlet water temperature of the gas water heater to reduce the output load of the burner. The reduction of the output load of the burner in the main heat exchanger includes: Obtain the current inlet water flow rate and the current output load of the burner; If the current inlet water flow rate is greater than or equal to a preset flow rate threshold, the first load reduction method is used to reduce the output load of the burner. If the current inlet water flow rate is less than a preset flow rate threshold and the current output load is greater than or equal to a preset load threshold, the first load reduction method is used to reduce the output load of the burner. If the current inlet water flow rate is less than a preset flow rate threshold and the current output load is less than a preset load threshold, the second load reduction method is used to reduce the output load of the burner.

10. The control method according to any one of claims 1-9, characterized in that, Also includes: If, after reducing the output load of the burner in the main heat exchanger, the real-time liquid level is still greater than the preset liquid level threshold within a preset time period; Control the gas water heater to stop.

11. A gas water heater, characterized in that, The gas water heater includes a main heat exchanger (1), a condenser heat exchanger (2), a main water inlet pipe (3), an atomizer (4), and a controller (5). The condenser heat exchanger (2) has a water collection chamber (21) for collecting the condensate produced by the condenser heat exchanger (2). The atomizer (4) is used to atomize the condensate. The main water inlet pipe (3), the condenser heat exchanger (2), and the main heat exchanger (1) are connected in sequence to form a water inlet path. The controller (5) is communicatively connected to the main heat exchanger (1). The controller (5) is used to execute the control method of the gas water heater according to any one of claims 1-10.

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