A control method for a gas water heating device

Abstract

The application provides a control method of a gas water heater, the gas water heater comprising: a first heat exchanger; a burner for heating the first heat exchanger; a second heat exchanger comprising a first flow channel and a second flow channel capable of heat exchange; the first flow channel is communicated with the first heat exchanger so that the liquid heated in the first heat exchanger flows into the first flow channel; the second flow channel is communicated with a domestic water inlet and a domestic water outlet; the control method comprises: obtaining a domestic water use signal of a user; controlling the first heat exchanger to be communicated with the first flow channel when the domestic water use signal is obtained; obtaining the heat energy stored in the first heat exchanger and capable of being released; obtaining the required heat load for heating the domestic water to a preset temperature; and controlling the burner to operate according to the first preset rule based on the required heat load and the heat energy stored in the first heat exchanger and capable of being released. The application improves the accuracy of the domestic water temperature control, and solves the problems of unstable domestic water outlet temperature and poor constant temperature performance of the gas water heater.

Description

Technical Field

[0001] This invention relates to the field of hot water engineering technology, and specifically to a control method for a gas-fired hot water device. Background Technology

[0002] A wall-hung boiler is short for a gas-fired wall-mounted heating boiler, which can use natural gas, liquefied petroleum gas, or city gas as energy sources for heating and providing domestic hot water.

[0003] When existing wall-hung boilers are used as water heaters to provide domestic hot water, the actual outlet water temperature is sometimes higher than the target temperature. This results in a poor user experience due to the excessively high temperature, especially when the inlet water temperature is high and the water flow rate is low. This can easily lead to the actual outlet water temperature being higher than the target temperature, resulting in poor temperature stability. Summary of the Invention

[0004] To address the problems in the prior art, embodiments of the present invention provide a control method for a gas-fired water heating device, which can at least partially solve the problems existing in the prior art.

[0005] This invention proposes a control method for a gas-fired water heating device, the gas-fired water heating device comprising:

[0006] First heat exchanger;

[0007] A burner for heating the first heat exchanger;

[0008] The second heat exchanger includes a first flow channel and a second flow channel for heat exchange; the first flow channel is connected to the first heat exchanger so that the heated liquid in the first heat exchanger flows into the first flow channel; the second flow channel is connected to a domestic water inlet and a domestic water outlet.

[0009] The control method includes:

[0010] Acquire user's domestic water usage signals;

[0011] When the user's domestic water usage signal is received, the first heat exchanger is connected to the first flow channel.

[0012] Obtain the heat energy that can be released from the first heat exchanger;

[0013] Obtain the required heat load to heat the domestic water to a preset temperature;

[0014] The burner is controlled to operate according to a first preset rule based on the obtained required heat load and the heat energy that can be released from the first heat exchanger.

[0015] Furthermore, the first preset rule includes controlling the burner to start combustion when the heat energy stored in the first heat exchanger is released to the point that the temperature of the domestic water flowing through the second channel can no longer rise.

[0016] Furthermore, the first preset rule includes obtaining a first time when the heat energy stored in the first heat exchanger is released to a point where the temperature of the domestic water flowing through the second channel cannot continue to rise, and controlling the burner to start combustion after the first time is turned off.

[0017] Furthermore, the first time is the time calculated by dividing the heat energy that can be released stored in the first heat exchanger by the required heat load.

[0018] Furthermore, the control method further includes:

[0019] Obtain the heat energy generated when the burner is ignited;

[0020] The burner is controlled to operate according to a second preset rule based on the required heat load, the heat energy generated when the burner is ignited, and the heat energy released from the energy stored in the first heat exchanger.

[0021] Furthermore, the second preset rule includes obtaining a second time when the heat energy stored in the first heat exchanger and the heat energy generated when the burner is ignited are released to a point where the temperature of the domestic water flowing through the second channel cannot continue to rise, and controlling the burner to start combustion after the second time is turned off.

[0022] Furthermore, the second time is the time calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy generated when the burner is ignited by the required heat load.

[0023] Furthermore, the heat energy generated by the burner ignition is a preset value stored in the controller of the gas-fired water heater.

[0024] Furthermore, the control method further includes:

[0025] After the burner starts combustion, when the required heat load is less than the minimum load that the burner can supply, the heat energy that can be released stored in the first heat exchanger is acquired in real time.

[0026] When the time it takes for the heat energy stored in the first heat exchanger to heat the domestic water flowing through the second channel to the preset temperature is longer than the preset time, the burner is controlled to stop burning, and at the same time, the liquid in the first heat exchanger is controlled to continue flowing into the first channel to continue heating the domestic water flowing through the second channel to the preset temperature.

[0027] When the heat stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second channel to the preset temperature, the burner is controlled to restart combustion.

[0028] Furthermore, the step of obtaining the heat energy stored in the first heat exchanger and releasing it includes:

[0029] Obtain the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel;

[0030] Based on the outlet water temperature of the first heat exchanger, the inlet water temperature of the second flow channel, and a first preset correspondence, the heat energy that can be released stored in the first heat exchanger is obtained; wherein, the first preset correspondence is the correspondence between the heat energy that can be released stored in the first heat exchanger and the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel.

[0031] Furthermore, in the first preset correspondence, the difference between the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel is proportional to the heat energy that can be released stored in the first heat exchanger.

[0032] Furthermore, obtaining the required heat load to heat the domestic water to a preset temperature includes:

[0033] Obtain the inlet water temperature and inlet water flow rate of the second flow channel;

[0034] The required heat load is obtained based on the preset temperature, the inlet water temperature of the second flow channel, the inlet water flow rate of the second flow channel, and the second preset correspondence; the second preset correspondence is the correspondence between the required heat load and the preset temperature, the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel.

[0035] Furthermore, in the second preset correspondence, the difference between the preset temperature and the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel are both proportional to the required heat load.

[0036] Furthermore, the gas-fired water heater also includes a circulation pump, which is installed in the water path between the first heat exchanger and the first flow channel. The circulation pump can drive the liquid in the first heat exchanger to flow into the first flow channel and drive the liquid after flowing through the first flow channel to flow back to the first heat exchanger.

[0037] Furthermore, the gas-fired water heater also includes a domestic water circulation pump, which is installed in the waterway between the second flow channel and the domestic water inlet.

[0038] Furthermore, the gas-fired water heater also includes a heating outlet and a switching device. The switching device includes a first port connected to the outlet of the first heat exchanger, a second port connected to the inlet of the first flow channel, and a third port connected to the heating outlet. The switching device includes at least a first state in which the first port is connected to the second port and a second state in which the first port is connected to the third port. When the switching device is in the first state, it allows the liquid flowing out of the first heat exchanger to flow into the first flow channel to heat the domestic water flowing through the second flow channel. When the switching device is in the second state, it allows the liquid flowing out of the first heat exchanger to flow towards the heating outlet.

[0039] Furthermore, the control method further includes:

[0040] The heat energy that can be released is obtained from the water path between the first heat exchanger and the first flow channel;

[0041] The burner is controlled to operate according to a third preset rule based on the obtained required heat load, the heat energy that can be released stored in the first heat exchanger, and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel.

[0042] Furthermore, the third preset rule includes obtaining a third time when the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel are released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the third time is turned off.

[0043] Furthermore, the third time is the time calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel by the required heat load.

[0044] Furthermore, the heat energy stored in the first heat exchanger that can be released is the heat energy stored in the liquid within the first heat exchanger that can be transferred to the domestic water flowing through the second flow channel via the first flow channel of the second heat exchanger.

[0045] Furthermore, the first heat exchanger has a coil-type structure.

[0046] Furthermore, the volume of the first heat exchanger is greater than or equal to 1 liter.

[0047] The control method for a gas-fired water heater provided in this invention acquires a user's domestic water usage signal; when the user's domestic water usage signal is acquired, the first heat exchanger is connected to the first flow channel; the heat energy that can be released stored in the first heat exchanger is acquired; the required heat load to heat the domestic water to a preset temperature is acquired; and the burner is controlled to operate according to a first preset rule based on the acquired required heat load and the heat energy that can be released stored in the first heat exchanger. This method can reduce the occurrence of domestic water temperatures that are too high and exceed the user's set temperature, solves the problems of unstable domestic water outlet temperature and poor constant temperature performance of gas-fired water heaters, and improves the accuracy of domestic water temperature control. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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. In the drawings:

[0049] Figure 1 This is a schematic diagram of the structure of the gas-fired water heater provided in the first embodiment of the present invention.

[0050] Figure 2 This is a flowchart illustrating the control method of the gas-fired hot water device provided in the second embodiment of the present invention.

[0051] Figure 3 This is a flowchart illustrating the control method of the gas-fired hot water device provided in the third embodiment of the present invention.

[0052] Figure 4 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the fourth embodiment of the present invention.

[0053] Figure 5 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the fifth embodiment of the present invention.

[0054] Figure 6 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the sixth embodiment of the present invention.

[0055] Figure 7 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the seventh embodiment of the present invention.

[0056] Figure 8 This is a schematic diagram of the structure of the gas-fired water heater provided in the eighth embodiment of the present invention.

[0057] Figure 9This is a schematic diagram comparing the inlet and outlet water temperatures of the second flow channel provided in the ninth embodiment of the present invention.

[0058] Explanation of reference numerals in the attached figures:

[0059] 1. First heat exchanger;

[0060] 2. Burner;

[0061] 3. Second heat exchanger;

[0062] 4. First flow channel;

[0063] 5. Second flow channel;

[0064] 6. Circulating pump;

[0065] 7. Domestic water circulation pump;

[0066] 8. Switching device;

[0067] 81. The first bite;

[0068] 82. The second bite;

[0069] 83. The third bite;

[0070] 9. First temperature sensor;

[0071] 10. Second temperature sensor;

[0072] 11. Third temperature sensor;

[0073] 12. Fourth temperature sensor;

[0074] 13. Flow sensor. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0076] Figure 1 This is a schematic diagram of the structure of the gas-fired water heater provided in the first embodiment of the present invention, as shown below. Figure 1 As shown, the gas-fired water heating device provided in this embodiment of the invention includes:

[0077] First heat exchanger 1;

[0078] Burner 2 for heating the first heat exchanger 1;

[0079] The second heat exchanger 3 includes a first flow channel 4 and a second flow channel 5 for heat exchange; the first flow channel 4 is connected to the first heat exchanger 1 so that the heated liquid in the first heat exchanger 1 flows into the first flow channel 4; the second flow channel 5 is connected to the domestic water inlet and the domestic water outlet.

[0080] Specifically, the gas-fired water heater provided in this embodiment of the invention can heat domestic water. Liquid flowing into the first heat exchanger 1 is heated by the burner 2, increasing its temperature, and then flows into the first flow channel 4. In the second heat exchanger 3, the liquid in the first flow channel 4 exchanges heat with the domestic water in the second flow channel 5, causing the temperature of the domestic water in the second flow channel 5 to rise. After being heated, the domestic water in the second flow channel 5 flows out from the domestic water outlet for user use.

[0081] A circulation pump 6 can be installed in the water path between the first heat exchanger 1 and the first flow channel 4 to drive the liquid in the first heat exchanger 1 into the first flow channel 4 and drive the liquid after flowing through the first flow channel 4 back into the first heat exchanger 1. A domestic water circulation pump 7 can be installed in the water path between the second flow channel 5 and the domestic water inlet. The domestic water circulation pump 7 can drive the domestic water in the domestic water inlet into the second flow channel 5 and drive the domestic water after flowing through the second flow channel 5 out to the domestic water outlet.

[0082] A switching device 8 can be installed in the water path between the first flow channel 4 and the outlet of the first heat exchanger 1. The switching device 8 includes a first port 81, a second port 82, and a third port 83. The first port 81 is connected to the outlet of the first heat exchanger 1, the second port 82 is connected to the inlet of the first flow channel 4, and the third port 83 is connected to the heating outlet. When the first port 81 and the second port 82 are connected, the switching device 8 is in a first state, and the liquid being heated in the first heat exchanger 1 can flow into the first flow channel 4. When the first port 81 and the third port 83 are connected, the switching device 8 is in a second state, and the liquid in the first heat exchanger 1 flows to the heating outlet. The switching device 8 can be a three-way valve.

[0083] A first temperature sensor 9 can be installed in the waterway between the second flow channel 5 and the domestic water outlet. The first temperature sensor 9 is used to collect the outlet water temperature of the second flow channel 5.

[0084] It is understood that the gas-fired water heater has a controller. The controller, as the executing entity, is capable of executing the control method for the gas-fired water heater provided in this embodiment of the invention.

[0085] Figure 2 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the second embodiment of the present invention, as shown below. Figure 2 As shown, the control method for a gas-fired water heater provided in this embodiment of the invention can be applied to the aforementioned gas-fired water heater, including:

[0086] S101. Obtain the user's domestic water usage signal;

[0087] Specifically, when a user needs to use the aforementioned gas-fired water heater, they can turn it on via a control switch and set the target heating temperature, i.e., the preset temperature. The controller of the gas-fired water heater receives the control switch activation signal and the preset temperature, thereby obtaining the user's domestic water usage signal. It is understood that if the user has previously used a gas-fired water heater, they can turn it on via the control switch without setting the temperature; the controller will continue to use the previously set preset temperature.

[0088] S102. When the user's domestic water usage signal is obtained, control the first heat exchanger to connect with the first flow channel;

[0089] Specifically, after the controller receives the user's domestic water usage signal, it will control the first heat exchanger to connect with the first flow channel, so that the liquid flowing out of the first heat exchanger flows into the first flow channel, so that the liquid in the first flow channel can exchange heat with the domestic water in the second flow channel in the second heat exchanger.

[0090] For example, a three-way valve is installed between the first heat exchanger and the first flow channel. The three-way valve includes a first port connected to the outlet of the first heat exchanger, a second port connected to the inlet of the first flow channel, and a third port connected to the heating water outlet. After receiving a user's domestic water usage signal, the controller controls the first port and the second port of the three-way valve to connect, thus connecting the first heat exchanger and the first flow channel. When heating of the domestic water in the second flow channel is not required, the controller controls the first port and the second port of the three-way valve to disconnect, thereby preventing the first heat exchanger from connecting to the first flow channel. The controller can also control the first port and the third port of the three-way valve to connect, allowing the heated liquid in the first heat exchanger to flow into the heating circulation pipe through the heating water outlet, thereby providing heating functionality.

[0091] S103. Obtain the heat energy that can be released from the first heat exchanger;

[0092] Specifically, after acquiring the user's domestic water usage signal, the controller can acquire the heat energy stored in the first heat exchanger that can be released.

[0093] For example, the controller can calculate the heat energy that can be released stored in the first heat exchanger based on the detected outlet water temperature of the first heat exchanger, the inlet water temperature of the first flow channel, and a first preset correspondence. The first preset correspondence is pre-set and stored in the controller. For example, the first preset correspondence is Q1 = cm1(T2 - T3), where Q1 represents the heat energy that can be released stored in the first heat exchanger, T2 represents the outlet water temperature of the first heat exchanger, T3 represents the inlet water temperature of the second flow channel, m1 represents the mass of water stored in the first heat exchanger, c represents the specific heat capacity of water, and c and m1 are constants. T2 and T3 can be obtained by temperature sensors.

[0094] S104. Obtain the required heat load to heat the domestic water to a preset temperature;

[0095] Specifically, after acquiring the user's domestic water usage signal, the controller can detect the temperature of the domestic water flowing into the second channel (i.e., the inlet temperature of the second channel) using a temperature sensor; and it can detect the flow rate of the domestic water flowing through the second channel (i.e., the inlet flow rate of the second channel) using a flow sensor. The controller can then determine the required heat load to heat the domestic water to a preset temperature based on the inlet temperature of the second channel, the inlet flow rate of the second channel, and a preset temperature.

[0096] For example, according to the formula P = c(T0-T3)L, the required heat load P to heat the domestic water to the preset temperature can be calculated, where T0 represents the preset temperature, T3 represents the inlet water temperature of the second flow channel, L represents the inlet water flow rate of the second flow channel, and c represents the specific heat capacity of water.

[0097] S105. The burner is controlled to operate according to a first preset rule based on the obtained required heat load and the heat energy that can be released stored in the first heat exchanger.

[0098] Specifically, after obtaining the required heat load and the heat energy that can be released stored in the first heat exchanger, with the goal of heating the domestic water to a preset temperature, the burner is controlled to operate according to a first preset rule based on the required heat load and the heat energy that can be released stored in the first heat exchanger. The first preset rule is set according to actual needs, and this embodiment of the invention does not impose any limitations.

[0099] The control method for a gas-fired water heater provided in this invention acquires a user's domestic water usage signal; when the user's domestic water usage signal is acquired, the first heat exchanger is connected to the first flow channel; the heat energy that can be released stored in the first heat exchanger is acquired; the required heat load to heat the domestic water to a preset temperature is acquired; and the burner is controlled to operate according to a first preset rule based on the acquired required heat load and the heat energy that can be released stored in the first heat exchanger. This method can reduce the occurrence of domestic water temperatures that are too high and exceed the user's set temperature, solves the problems of unstable domestic water outlet temperature and poor constant temperature performance of gas-fired water heaters, and improves the accuracy of domestic water temperature control.

[0100] Based on the above embodiments, the first preset rule further includes controlling the burner to start combustion when the heat energy stored in the first heat exchanger is released to the point that the temperature of the domestic water flowing through the second flow channel can no longer rise.

[0101] Specifically, the burner can be left off initially, and the domestic water can be heated using the heat energy stored in the first heat exchanger to save gas. During the heating process, as the domestic water flows continuously in the second channel, the heat energy stored in the first heat exchanger is continuously consumed. When the controller detects that the heat energy stored in the first heat exchanger has been released to a level that can no longer raise the temperature of the domestic water flowing through the second channel, it can control the burner to start combustion to heat the first heat exchanger, increase the temperature of the liquid flowing into the first channel, and thus increase the outlet temperature of the second channel to a preset temperature.

[0102] For example, when the heat energy stored in the first heat exchanger is sufficient to heat the domestic water to a preset temperature, the burner is not turned on initially. During the process of heating the domestic water to the preset temperature, the controller can detect the outlet water temperature of the second flow channel through a temperature sensor. If the current outlet water temperature of the second flow channel is lower than the previous outlet water temperature, and the current outlet water temperature of the second flow channel is also lower than the preset temperature, then the controller can control the burner to start combustion.

[0103] For example, the controller can detect the outlet water temperature of the second flow channel using a temperature sensor. If, during the process of heating the domestic water to a preset temperature, the outlet water temperature of the second flow channel still has not reached the preset temperature after a set time, the controller can control the burner to start combustion. The set time is determined based on practical experience and is not limited in this embodiment of the invention.

[0104] For example, the controller can detect the inlet and outlet water temperatures of the second flow channel using a temperature sensor. During the process of heating the domestic water to a preset temperature, if the outlet water temperature of the second flow channel is not higher than the inlet water temperature of the second flow channel, the controller can control the burner to start combustion.

[0105] Based on the above embodiments, the first preset rule further includes obtaining a first time when the heat energy stored in the first heat exchanger is released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the first time is turned off.

[0106] Specifically, with the burner in the off state, the controller calculates a first time based on the heat energy stored in the first heat exchanger and the required heat load. During this first time, the heat energy stored in the first heat exchanger is sufficient to continuously raise the temperature of the domestic water. After the first time, the heat energy stored in the first heat exchanger is released until it can no longer raise the temperature of the domestic water flowing through the second channel, and the domestic water temperature does not reach the preset temperature. In this case, the controller will control the burner to start combustion to heat the first heat exchanger, increase the temperature of the liquid flowing into the first channel, and thereby increase the temperature of the domestic water in the second channel to the preset temperature.

[0107] Based on the above embodiments, the first time is further defined as the time calculated by dividing the heat energy that can be released stored in the first heat exchanger by the required heat load.

[0108] Specifically, the controller divides the quotient of the heat energy that can be released stored in the first heat exchanger by the required heat load, and uses this quotient as the first time.

[0109] For example, the first time t1 is calculated according to the formula t1 = E / P, where E represents the heat energy that can be released from the first heat exchanger and P represents the required heat load.

[0110] When using a gas-fired water heater, heat energy accumulates in the first heat exchanger. In existing technologies, when controlling the temperature of gas-fired water heaters such as wall-hung boilers, the burner ignites directly upon receiving a user's water usage signal without considering the accumulated heat energy in the first heat exchanger. This results in the domestic water temperature exceeding the user's desired temperature, leading to a poor user experience. This is especially true when the gas-fired water heater is frequently used within a short period, causing a large amount of heat energy to accumulate in the first heat exchanger, resulting in consistently high water temperatures each time the user uses the water. The control method for a gas-fired water heater provided in this invention releases the heat energy stored in the first heat exchanger before starting the burner. This facilitates precise control of the domestic water temperature, making the outlet water temperature more comfortable and improving the user's water usage experience. Furthermore, if the heat energy stored in the first heat exchanger is sufficient to heat the domestic water to the preset temperature, there is no need to start the burner, thus saving gas.

[0111] Figure 3 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the third embodiment of the present invention, as shown below. Figure 3 As shown, based on the above embodiments, the control method for the gas-fired water heater provided in this embodiment of the invention further includes:

[0112] S301. Obtain the heat energy generated when the burner is ignited;

[0113] Specifically, the controller can acquire the heat energy generated when the burner ignites. The heat energy generated when the burner ignites is preset.

[0114] S302. Based on the obtained required heat load, the heat energy generated when the burner is ignited and burned, and the heat energy that can be released from the first heat exchanger, the burner is controlled to operate according to the second preset rule.

[0115] Specifically, with the goal of heating the domestic water to a preset temperature, the controller controls the operation of the burner according to a second preset rule based on the required heat load, the heat energy generated when the burner ignites and burns, and the heat energy released from the required heat load and the energy stored in the first heat exchanger. The second preset rule is set according to actual needs, and this embodiment of the invention does not impose limitations.

[0116] Based on the above embodiments, the second preset rule further includes obtaining a second time when the heat energy stored in the first heat exchanger and the heat energy generated when the burner is ignited are released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the second time is turned off.

[0117] Specifically, before controlling the burner to start combustion, the controller calculates a second time based on the heat energy that can be released stored in the first heat exchanger, the heat energy generated when the burner ignites, and the required heat load. After the second time, the controller controls the burner to start combustion to heat the first heat exchanger, increase the temperature of the liquid flowing into the first flow channel, and thereby increase the temperature of the domestic water in the second flow channel to a preset temperature.

[0118] Based on the above embodiments, the second time is further calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy generated when the burner is ignited by the required heat load.

[0119] Specifically, the controller divides the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy generated when the burner is ignited by the required heat load by the quotient value, and uses this as the second time.

[0120] For example, the second time t2 is calculated according to the formula t2=(E+Q0) / P, where E represents the heat energy that can be released stored in the first heat exchanger, Q0 represents the heat energy generated when the burner is ignited and burned, and P represents the required heat load.

[0121] Based on the above embodiments, the heat energy generated by the burner ignition is a preset value stored in the controller of the gas-fired water heater. The preset value is set according to actual conditions, and this embodiment of the invention does not impose any limitations.

[0122] The control method for the gas-fired water heater provided in this embodiment of the invention allows for a second time before the burner is turned on. This releases the heat energy stored in the first heat exchanger, which is beneficial for precise control of the domestic water temperature. Furthermore, it helps to suppress the rapid temperature rise during ignition, which is beneficial for maintaining temperature stability.

[0123] Figure 4 This is a schematic flowchart of the control method for a gas-fired hot water device provided in the fourth embodiment of the present invention, as shown below. Figure 4 As shown, based on the above embodiments, the control method further includes:

[0124] S401. After the burner starts combustion, when the required heat load is less than the minimum load that the burner can supply, the heat energy that can be released stored in the first heat exchanger is obtained in real time.

[0125] Specifically, after the burner starts combustion, the controller compares the required heat load with the minimum load that the burner can supply. If the required load is less than the minimum load, the controller acquires the heat energy stored in the first heat exchanger that can be released in real time. The minimum load is preset.

[0126] For example, the outlet water temperature T2 of the first heat exchanger and the inlet water temperature T3 of the second flow channel are detected in real time. Then, according to the formula Q1=cm1(T2-T3), the heat energy Q1 that can be released stored in the first heat exchanger is calculated, where m1 represents the mass of water stored in the first heat exchanger, c represents the specific heat capacity of water, and c and m1 are constants.

[0127] S402. When the time it takes for the heat energy stored in the first heat exchanger to heat the domestic water flowing through the second channel to the preset temperature is longer than the preset time, the burner is controlled to stop burning, and at the same time, the liquid in the first heat exchanger is controlled to continue flowing into the first channel to continue heating the domestic water flowing through the second channel to the preset temperature.

[0128] Specifically, the controller can obtain the time required for the released heat energy stored in the first heat exchanger to heat the domestic water flowing through the second flow channel to the preset temperature. Then, it compares this time with a preset duration. If the time exceeds the preset duration, the controller can control the burner to stop combustion. Simultaneously, the connection between the first heat exchanger and the first flow channel is maintained, allowing liquid in the first heat exchanger to continue flowing into the first flow channel, thereby continuing to heat the domestic water flowing through the second flow channel until it exits the second flow channel and reaches the preset temperature. The preset duration is set according to actual needs, and this embodiment of the invention does not impose a limitation.

[0129] The time t3 for the released heat energy stored in the first heat exchanger to heat the domestic water flowing through the second flow channel to the preset temperature can be determined by the formula t3 = E. ′ / P is calculated, where E ′ P represents the heat energy that can be released stored in the first heat exchanger, which is acquired in real time, and P represents the heat load required to heat the domestic water flowing through the second channel to the preset temperature.

[0130] After the burner starts combustion, if the required heat load is less than the minimum load that the burner can supply, and the burner operates at its minimum load, the domestic water outlet will experience overheating, meaning the actual outlet temperature of the domestic water will be higher than the preset temperature, affecting the user's water experience. When the time required for the released heat energy stored in the first heat exchanger to heat the domestic water flowing through the second flow channel to the preset temperature is longer than a preset duration, the burner is controlled to stop combustion. The released heat energy stored in the first heat exchanger is then used to continue heating the domestic water. This consumption of the heat energy stored in the first heat exchanger helps to more accurately control the domestic water flowing out of the second flow channel at the preset temperature, reducing or even avoiding overheating and improving the user's water experience.

[0131] S403. When the heat stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second channel to a preset temperature, the burner is controlled to restart combustion.

[0132] Specifically, after the burner stops combustion, the released heat energy stored in the first heat exchanger heats the domestic water flowing through the second channel to a preset temperature. Due to the continuous flow of domestic water in the second channel, the released heat energy stored in the first heat exchanger is continuously consumed. When the released heat energy stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second channel to the preset temperature, the controller will control the burner to restart combustion in order to heat the domestic water flowing through the second channel to the preset temperature.

[0133] For example, the controller can detect the outlet water temperature T4 of the second flow channel using a sensor. If T4 is less than the preset temperature, it indicates that the heat stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second flow channel to the preset temperature. In this case, the burner can be controlled to start combustion. Furthermore, since it is difficult to maintain the outlet water temperature of the second flow channel at the preset temperature, it is usually controlled to fluctuate within a certain range around the preset temperature. For example, setting the outlet water temperature of the second flow channel to fluctuate within ±β℃ of the preset temperature T0 meets the outlet water temperature control requirements. Therefore, if T4 is less than T0-β, it indicates that the heat stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second flow channel to the preset temperature. In this case, the burner can be controlled to start combustion.

[0134] Figure 5 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the fifth embodiment of the present invention, as shown below. Figure 5 As shown, based on the above embodiments, further, obtaining the heat energy stored in the first heat exchanger that can be released includes:

[0135] S501. Obtain the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel;

[0136] Specifically, the controller can acquire the outlet water temperature of the first heat exchanger through a third temperature sensor, and can detect and acquire the inlet water temperature of the second flow channel through a fourth temperature sensor. The third temperature sensor can be installed in the water path between the first flow channel and the outlet of the first heat exchanger; the fourth temperature sensor can be installed in the water path between the second flow channel and the domestic water inlet.

[0137] S502. Based on the outlet water temperature of the first heat exchanger, the inlet water temperature of the second flow channel, and the first preset correspondence, obtain the heat energy that can be released stored in the first heat exchanger; wherein, the first preset correspondence is the correspondence between the heat energy that can be released stored in the first heat exchanger and the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel.

[0138] Specifically, the controller maps the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel to the first preset correspondence, thereby obtaining the heat energy stored in the first heat exchanger that can be released. The first preset correspondence is the relationship between the heat energy stored in the first heat exchanger that can be released and the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel. This relationship can be set according to actual needs, and this embodiment of the invention does not impose any limitations.

[0139] Based on the above embodiments, further, in the first preset correspondence, the difference between the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel is proportional to the heat energy that can be released stored in the first heat exchanger. That is, the greater the difference between the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel, the more heat energy that can be released stored in the first heat exchanger.

[0140] For example, the first preset correspondence is Q1 = cm1(T2-T3), where Q1 represents the heat energy that can be released stored in the first heat exchanger, T2 represents the outlet water temperature of the first heat exchanger, T3 represents the inlet water temperature of the second flow channel, m1 represents the mass of water stored in the first heat exchanger, c represents the specific heat capacity of water, and c and m1 are constants.

[0141] Figure 6 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the sixth embodiment of the present invention, as shown below. Figure 6 As shown, based on the above embodiments, further, obtaining the required heat load to heat the domestic water to a preset temperature includes:

[0142] S601. Obtain the inlet water temperature and the inlet water flow rate of the second flow channel;

[0143] Specifically, the controller can acquire the inlet water flow rate of the second flow channel through a flow sensor, and can detect and acquire the inlet water temperature of the second flow channel through a fourth temperature sensor. The flow sensor can be installed in the water path between the second flow channel and the domestic water inlet; the fourth temperature sensor can also be installed in the water path between the second flow channel and the domestic water inlet.

[0144] S602. Obtain the required heat load based on the preset temperature, the inlet water temperature of the second flow channel, the flow rate of the second flow channel, and the second preset correspondence; wherein, the second preset correspondence is the correspondence between the heat load and the preset temperature, the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel.

[0145] Specifically, the controller incorporates the preset temperature, the inlet water temperature of the second flow channel, and the flow rate of the second flow channel into a second preset correspondence to obtain the required heat load. The second preset correspondence is the relationship between the heat load and the preset temperature, the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel.

[0146] Based on the above embodiments, further, in the second preset correspondence, the difference between the preset temperature and the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel are both proportional to the required heat load. That is, when the difference between the preset temperature and the inlet water temperature of the second flow channel remains unchanged, an increase in the inlet water flow rate of the second flow channel will increase the required heat load; when the inlet water flow rate of the second flow channel remains unchanged, an increase in the difference between the preset temperature and the inlet water temperature of the second flow channel will increase the required heat load.

[0147] For example, the second preset correspondence is: P = c(T0-T3)L, where P represents the required heat load, T0 represents the preset temperature, T3 represents the inlet water temperature of the second flow channel, L represents the inlet water flow rate of the second flow channel, and c represents the specific heat capacity of water.

[0148] like Figure 1 As shown, based on the above embodiments, the gas-fired water heater further includes a circulation pump 6, which is installed in the water path between the first heat exchanger 1 and the first flow channel 4. The circulation pump 6 can drive the liquid in the first heat exchanger 1 to flow into the first flow channel 4 and drive the liquid after flowing through the first flow channel 4 to flow back to the first heat exchanger 1.

[0149] like Figure 1As shown, based on the above embodiments, the gas-fired water heater further includes a domestic water circulation pump 7, which is installed in the waterway between the second flow channel 5 and the domestic water inlet. The domestic water circulation pump 7 can drive the domestic water in the domestic water inlet into the second flow channel 5 and drive the domestic water after flowing through the second flow channel 5 to the domestic water outlet.

[0150] like Figure 1 As shown, based on the above embodiments, the gas-fired water heater further includes a heating outlet and a switching device 8. The switching device 8 includes a first port 81 connected to the outlet of the first heat exchanger, a second port 82 connected to the inlet of the first flow channel, and a third port 83 connected to the heating outlet. The switching device 8 includes at least a first state in which the first port 81 and the second port 82 are connected, and a second state in which the first port 81 and the third port 83 are connected. When the switching device 8 is in the first state, the liquid flowing out of the first heat exchanger 1 can flow into the first flow channel 4 to heat the domestic water flowing through the second flow channel 5. When the switching device 8 is in the second state, the liquid flowing out of the first heat exchanger 1 can flow to the heating outlet.

[0151] The switching device 8 can be a three-way valve or other device, and the choice is made according to actual needs. This embodiment of the invention does not limit the choice.

[0152] Figure 7 This is a flowchart illustrating the control method for a gas-fired hot water device provided in the seventh embodiment of the present invention, as shown below. Figure 7 As shown, based on the above embodiments, the control method further includes:

[0153] S701. Obtain the heat energy that can be released from the water path between the first heat exchanger and the first flow channel;

[0154] Specifically, in order to more accurately control the outlet water temperature of the second flow channel, the heat energy stored in the water path between the first heat exchanger and the first flow channel that can be released is taken into account. The controller can acquire both the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel.

[0155] For example, the controller can calculate the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel based on the detected outlet water temperature of the first heat exchanger, the inlet water temperature of the first flow channel, and a third preset correspondence. The third preset correspondence is pre-set and stored in the controller, and it represents the relationship between the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel and the outlet water temperature of the first heat exchanger and the inlet water temperature of the first flow channel. For example, the third preset correspondence is Q2 = cm2(T2 - T3), where Q2 represents the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel, T2 represents the outlet water temperature of the first heat exchanger, T3 represents the inlet water temperature of the second flow channel, m2 represents the mass of water stored in the water path between the first heat exchanger and the first flow channel, c represents the specific heat capacity of water, and c and m2 are constants.

[0156] S702. The burner is controlled to operate according to the third preset rule based on the obtained required heat load, the heat energy that can be released stored in the first heat exchanger, and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel.

[0157] Specifically, after obtaining the required heat load, the heat energy that can be released stored in the first heat exchanger, and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel, with the goal of heating the domestic water to a preset temperature, the burner is controlled to operate according to a third preset rule based on the required heat load, the heat energy that can be released stored in the first heat exchanger, and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel. The third preset rule is set according to actual needs, and this embodiment of the invention does not limit its implementation. The specific implementation process of this step is similar to that of step S105, which controls the burner to operate according to the first preset rule based on the obtained required heat load and the heat energy that can be released stored in the first heat exchanger, and will not be described in detail here.

[0158] For example, the third preset rule includes controlling the burner to start combustion when the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel are released to the point that the temperature of the domestic water flowing through the second flow channel can no longer rise.

[0159] Based on the above embodiments, the third preset rule further includes obtaining a third time when the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel are released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the third time is turned off.

[0160] Specifically, with the burner off, the controller calculates a third time period based on the heat energy stored in the first heat exchanger, the heat energy stored in the water path between the first heat exchanger and the first flow channel, and the required heat load. During this third time period, the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel are sufficient to continuously raise the domestic water temperature. After the third time period, if the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel decreases to the point where the domestic water temperature flowing through the second flow channel can no longer rise, and the domestic water temperature does not reach the preset temperature, then the controller will control the burner to start combustion to heat the first heat exchanger, increase the temperature of the liquid flowing into the first flow channel, and thereby increase the temperature of the domestic water in the second flow channel to the preset temperature.

[0161] Based on the above embodiments, the third time is further calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel by the required heat load.

[0162] Specifically, the controller calculates the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel, and then divides the sum by the required heat load to obtain a quotient value, which is used as the third time.

[0163] For example, the third time t3 is calculated according to the formula t3=(E1-E2) / P, where E1 represents the heat energy that can be released stored in the first heat exchanger, E2 represents the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel, and P represents the required heat load.

[0164] Based on the above embodiments, the control method further includes:

[0165] The burner is controlled to operate according to the fourth preset rule based on the obtained required heat load, the heat energy generated when the burner is ignited, the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel.

[0166] Specifically, with the goal of heating the domestic water to a preset temperature, the controller controls the burner's operation according to a fourth preset rule based on the required heat load, the heat energy generated during burner ignition, the required heat load, the heat energy stored in the first heat exchanger, and the heat energy stored in the water path between the first heat exchanger and the first flow channel. The fourth preset rule is set according to actual needs and is not limited in this embodiment of the invention. The specific implementation process of this step is similar to that of step S302, which controls the burner's operation according to the second preset rule based on the obtained required heat load, the heat energy generated during burner ignition, and the heat energy stored in the first heat exchanger; therefore, it will not be described in detail here.

[0167] For example, the fourth preset rule includes obtaining a fourth time interval for releasing the heat energy generated when the burner ignites, the heat energy stored in the first heat exchanger, and the heat energy stored in the water path between the first heat exchanger and the first flow channel until the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the fourth time interval. The fourth time interval is calculated by dividing the sum of the heat energy generated when the burner ignites, the heat energy stored in the first heat exchanger, and the heat energy stored in the water path between the first heat exchanger and the first flow channel by the required heat load.

[0168] The control method for a gas-fired water heater provided in this embodiment of the invention, in the process of controlling the domestic water temperature, takes into account the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel, which can further improve the accuracy of domestic water temperature control.

[0169] Based on the above embodiments, the heat energy stored in the first heat exchanger that can be released is the heat energy stored in the liquid in the first heat exchanger that can be transferred to the domestic water flowing through the second flow channel through the first flow channel of the second heat exchanger.

[0170] Based on the above embodiments, the first heat exchanger is further described as a coil-type structure.

[0171] The first heat exchanger in the coil structure can store a large amount of liquid, thus easily storing a large amount of releaseable heat energy. The control method for the gas-fired water heater provided in this embodiment of the invention facilitates the release of releaseable heat energy stored in the liquid within the coil structure, improving the accuracy of domestic water temperature control.

[0172] Based on the above embodiments, the volume of the first heat exchanger is greater than or equal to 1 liter. A larger volume first heat exchanger can store more liquid, thus easily storing more releaseable heat energy. The control method for the gas-fired water heater provided in this embodiment of the invention facilitates the release of releaseable heat energy stored in the liquid within the larger first heat exchanger, improving the accuracy of domestic water temperature control.

[0173] like Figure 1 As shown, based on the above embodiments, the gas-fired water heater further includes:

[0174] A first temperature sensor 9 is installed in the water path between the second flow channel 5 and the domestic water outlet. The first temperature sensor 9 is used to collect the outlet water temperature of the second flow channel 5. By comparing the outlet water temperature of the second flow channel 5 with a preset temperature, it can be determined whether the outlet water temperature of the second flow channel 5 has reached the preset temperature.

[0175] Figure 8 This is a schematic diagram of the structure of the gas-fired hot water device provided in the eighth embodiment of the present invention, as shown below. Figure 8 As shown, based on the above embodiments, the gas-fired water heater further includes:

[0176] The second temperature sensor 10 is disposed in the water path between the first flow channel 4 and the inlet of the first heat exchanger 1. The second temperature sensor 10 is used to collect the inlet water temperature of the first heat exchanger 1.

[0177] The third temperature sensor 11 is installed in the water path between the first flow channel 4 and the outlet of the first heat exchanger 1. The third temperature sensor 11 is used to collect the outlet water temperature of the first heat exchanger 1.

[0178] The fourth temperature sensor 12 is disposed in the water path between the second flow channel 5 and the domestic water inlet. The fourth temperature sensor 12 is used to collect the inlet water temperature of the second flow channel 5.

[0179] Flow sensor 13 is installed in the water path between the second flow channel 5 and the domestic water inlet. Flow sensor 13 is used to collect the inlet flow rate of the second flow channel 5.

[0180] Figure 9This is a schematic diagram comparing the outlet water temperature of the second flow channel provided in the ninth embodiment of the present invention, as shown below. Figure 9 As shown, the control method in the prior art and the control method of the gas water heater provided in the embodiment of the present invention are respectively applied to the gas water heater provided in the embodiment of the present invention. Under the same initial operating conditions, the outlet water temperature of the second flow channel is controlled. The inlet water temperature of the second flow channel is 20°C, the preset temperature is 38°C, and the required heat load is less than the minimum load that the burner of the gas water heater can supply.

[0181] The first temperature curve is the outlet water temperature curve of the second channel obtained using the existing control method. It can be seen that as the water usage time increases, the outlet water temperature of the second channel exceeds 38℃, and after the water usage time exceeds 90ms, the temperature remains above 40℃, significantly exceeding the user-set temperature. This is because the existing control method cannot release the accumulated heat energy in the first heat exchanger, and the burner's minimum load in the gas-fired water heater is too high, causing the amount of heat energy stored in the first heat exchanger to increase, resulting in a persistently high outlet water temperature in the second channel.

[0182] The second temperature curve is the outlet water temperature curve of the second flow channel obtained by applying the control method of the gas-fired water heater provided in this embodiment of the invention. It can be seen that after the outlet water temperature of the second flow channel rises to 38°C, it fluctuates around 38°C and does not exceed 40°C. The control method of the gas-fired water heater provided in this embodiment of the invention, because it considers the heat energy that can be released stored in the first heat exchanger during the temperature control process, can release the heat energy that can be released stored in the first heat exchanger in a timely manner, reducing the occurrence of water temperature exceeding the user-set temperature, providing users with a better water use experience, and because it can effectively utilize the heat energy that can be released stored in the first heat exchanger to heat domestic water, it can also save gas.

[0183] It is understood that, in the embodiments of this specification, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0184] In the description of this specification, the references to terms such as "an embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0185] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for a gas-fired hot water device, characterized in that, The gas-fired hot water device includes: First heat exchanger; A burner for heating the first heat exchanger; the first heat exchanger is a coil type structure, and the volume of the first heat exchanger is greater than or equal to 1 liter; The second heat exchanger includes a first flow channel and a second flow channel for heat exchange; the first flow channel is connected to the first heat exchanger so that the heated liquid in the first heat exchanger flows into the first flow channel; the second flow channel is connected to a domestic water inlet and a domestic water outlet. The control method includes: Acquire user's domestic water usage signals; When the user's domestic water usage signal is received, the first heat exchanger is connected to the first flow channel. Obtain the heat energy that can be released stored in the first heat exchanger; wherein, the heat energy that can be released stored in the first heat exchanger is the heat energy released by the water stored in the first heat exchanger; Obtain the required heat load to heat the domestic water to a preset temperature; The burner is controlled to operate according to a first preset rule based on the obtained required heat load and the heat energy that can be released from the first heat exchanger. The first preset rule includes controlling the burner to start combustion when the heat energy stored in the first heat exchanger is released to the point that the temperature of the domestic water flowing through the second flow channel can no longer rise. The control method further includes: After the burner starts combustion, when the required heat load is less than the minimum load that the burner can supply, the heat energy that can be released stored in the first heat exchanger is acquired in real time. When the time it takes for the heat energy stored in the first heat exchanger to heat the domestic water flowing through the second channel to the preset temperature is longer than the preset time, the burner is controlled to stop burning, and at the same time, the liquid in the first heat exchanger is controlled to continue flowing into the first channel to continue heating the domestic water flowing through the second channel to the preset temperature. When the heat stored in the first heat exchanger is insufficient to heat the domestic water flowing through the second channel to the preset temperature, the burner is controlled to restart combustion.

2. The control method for the gas-fired hot water device as described in claim 1, characterized in that, The first preset rule includes obtaining a first time when the heat energy stored in the first heat exchanger is released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the first time is turned off.

3. The control method for the gas-fired hot water device as described in claim 2, characterized in that, The first time is the time calculated by dividing the heat energy that can be released stored in the first heat exchanger by the required heat load.

4. The control method for the gas-fired hot water device as described in claim 1, characterized in that, The control method further includes: Obtain the heat energy generated when the burner is ignited; The burner is controlled to operate according to a second preset rule based on the required heat load, the heat energy generated when the burner is ignited, and the heat energy released from the energy stored in the first heat exchanger.

5. The control method for the gas-fired hot water device as described in claim 4, characterized in that, The second preset rule includes obtaining a second time when the heat energy stored in the first heat exchanger and the heat energy generated when the burner is ignited are released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the second time is turned off.

6. The control method for a gas-fired hot water device as described in claim 5, characterized in that, The second time is the time calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy generated when the burner is ignited by the required heat load.

7. The control method for a gas-fired hot water device as described in claim 4, characterized in that, The heat energy generated by the burner ignition is a preset value stored in the controller of the gas-fired water heater.

8. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The process of obtaining the released thermal energy stored in the first heat exchanger includes: Obtain the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel; The heat energy that can be released stored in the first heat exchanger is obtained based on the outlet water temperature of the first heat exchanger, the inlet water temperature of the second flow channel, and a first preset correspondence. The first preset correspondence is the correspondence between the heat energy that can be released stored in the first heat exchanger and the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel.

9. The control method for a gas-fired hot water device as described in claim 8, characterized in that, In the first preset correspondence, the difference between the outlet water temperature of the first heat exchanger and the inlet water temperature of the second flow channel is proportional to the heat energy that can be released stored in the first heat exchanger.

10. The control method for a gas-fired hot water device as described in claim 1, characterized in that, Obtaining the required heat load to heat the domestic water to a preset temperature includes: Obtain the inlet water temperature and inlet water flow rate of the second flow channel; The required heat load is obtained based on the preset temperature, the inlet water temperature of the second flow channel, the inlet water flow rate of the second flow channel, and a second preset correspondence; the second preset correspondence is the correspondence between the required heat load and the preset temperature, the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel.

11. The control method for a gas-fired hot water device as described in claim 10, characterized in that, In the second preset correspondence, the difference between the preset temperature and the inlet water temperature of the second flow channel, and the inlet water flow rate of the second flow channel are both proportional to the required heat load.

12. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The gas-fired water heater also includes a circulation pump, which is installed in the water path between the first heat exchanger and the first flow channel. The circulation pump can drive the liquid in the first heat exchanger to flow into the first flow channel and drive the liquid after flowing through the first flow channel to flow back to the first heat exchanger.

13. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The gas-fired water heater also includes a domestic water circulation pump, which is installed in the waterway between the second flow channel and the domestic water inlet or the domestic water outlet.

14. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The gas-fired water heater further includes a heating outlet and a switching device. The switching device includes a first port connected to the outlet of the first heat exchanger, a second port connected to the inlet of the first flow channel, and a third port connected to the heating outlet. The switching device includes at least a first state in which the first port is connected to the second port and a second state in which the first port is connected to the third port. When the switching device is in the first state, it allows the liquid flowing out of the first heat exchanger to flow into the first flow channel to heat the domestic water flowing through the second flow channel. When the switching device is in the second state, it allows the liquid flowing out of the first heat exchanger to flow towards the heating outlet.

15. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The control method further includes: The heat energy that can be released is obtained from the water path between the first heat exchanger and the first flow channel; The burner is controlled to operate according to a third preset rule based on the obtained required heat load, the heat energy that can be released stored in the first heat exchanger, and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel.

16. The control method for a gas-fired hot water device as described in claim 15, characterized in that, The third preset rule includes obtaining a third time when the heat energy stored in the first heat exchanger and the heat energy stored in the water path between the first heat exchanger and the first flow channel are released to a point where the temperature of the domestic water flowing through the second flow channel cannot continue to rise, and controlling the burner to start combustion after the third time is turned off.

17. The control method for a gas-fired hot water device as described in claim 16, characterized in that, The third time is the time calculated by dividing the sum of the heat energy that can be released stored in the first heat exchanger and the heat energy that can be released stored in the water path between the first heat exchanger and the first flow channel by the required heat load.

18. The control method for a gas-fired hot water device as described in claim 1, characterized in that, The heat energy stored in the first heat exchanger that can be released is the heat energy stored in the liquid in the first heat exchanger that can be transferred to the domestic water flowing through the second flow channel through the first flow channel of the second heat exchanger.

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