A water heater and control method

Abstract

The present application belongs to the field of water heaters, and particularly relates to a water heater and a control method. The water heater comprises a shell, an inner container, an instant heating unit, a heat storage heating unit, a water flow switch, a control unit, a temperature sensor, a water inlet end, and a water outlet end. The water heater further comprises a heat exchanger and a pump. The water inlet end, the heat exchanger, the instant heating unit, and the water outlet end are sequentially connected to form an instant heating channel. The heat exchanger, the pump, and the inner container are connected to form a circulating heat exchange channel. The heat storage heating unit is used for heating a heat storage medium in the inner container. The control unit controls the working state of the instant heating unit, the heat storage heating unit, and the pump according to one or more of the working mode of the water heater, the water flow state, and the temperature. The control unit comprises a speed regulation module, and the control unit controls the rotating speed of the pump according to the temperature parameter of the water heater to regulate the water outlet temperature. The control method realizes constant temperature water outlet by controlling the power of the instant heating unit or the rotating speed of the pump.

Description

Technical Field

[0001] This invention belongs to the field of water heaters, and in particular to an electric water heater. Background Technology

[0002] Electric storage water heaters are energy-intensive, insufficient for multiple users, bulky and unsightly, prone to scale buildup affecting water hygiene, and have a risk of bursting due to pressure. Furthermore, the alternating high pressure and temperature can cause micro-cracks and corrosion in the enamel layer, leading to stress corrosion in the stainless steel tank. Instantaneous water heaters have high power consumption, making them unsuitable for most households. Even with high power, the water flow is low in winter, making simultaneous supply to multiple points impossible and resulting in a poor user experience. Dual-mode instantaneous water heaters attempt to combine the advantages of both, but their small tank size and rapid temperature drop necessitate the use of a thermostatic valve for a satisfactory bathing experience. However, due to scale, sediment, and high-temperature, high-pressure conditions, thermostatic valves have a high failure rate, exceeding market acceptance. Additionally, the small tank capacity of instantaneous water heaters makes them susceptible to scale buildup; in areas with severe scale buildup, half the volume can be filled within two to three years. Instantaneous water heaters also suffer from the same problems as storage-type heaters. To address the issues of limescale buildup and inner tank corrosion in instant water heaters, heat exchange water heaters have emerged on the market. However, existing heat exchange solutions present even greater problems than traditional water heaters. While they solve the limescale buildup issue in the inner tank and heating element, scale can still form inside the heat exchange tubes. This scale buildup can lead to poor heat exchange or even blockages, rendering the water unusable. This is far more detrimental than the effects of limescale buildup in storage water heaters. Furthermore, heat exchange water heaters suffer from temperature differences and lower efficiency. Because the heat exchanger is located inside the inner tank, there is often very hot water when the water is turned off and then turned back on, posing a risk of scalding. Therefore, these water heaters require a thermostatic valve for optimal performance. As mentioned above, thermostatic valves have a high failure rate.

[0003] Based on a comprehensive and in-depth understanding of electric water heater products and the market, this application presents a novel heat exchange solution and constant temperature technology, solving the aforementioned problems of traditional water heaters and possessing significant practical value. Summary of the Invention

[0004] To address the shortcomings of existing water heater technology, this invention provides a new technical solution.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A water heater includes a shell, an inner tank, an instant heating unit, a heat storage heating unit, a flow switch, a control unit, a temperature sensor, an inlet, and an outlet. It also includes a heat exchanger and a pump. The inlet, heat exchanger, instant heating unit, and outlet are connected sequentially to form an instant heating channel. The heat exchanger, pump, and inner tank are connected to form a circulating heat exchange channel. The heat storage heating unit heats the heat storage medium in the inner tank. The control unit controls the operating status of the instant heating unit, heat storage heating unit, and pump based on one or more of the water heater's operating mode, water flow state, and temperature. The control unit includes a speed control module, which controls the pump speed according to the water heater's temperature parameters to adjust the outlet water temperature.

[0007] Optionally, the inner liner is in communication with the atmosphere and further includes a liquid level sensing unit and a water inlet valve. The liquid level sensing unit is installed on the inner liner or a component in communication with the inner liner and is used to sense the liquid level in the inner liner. The inner liner is connected to the instant heating channel through the water inlet valve.

[0008] Furthermore, the water inlet valve is connected to the inner tank through a heat exchanger, which is used to remove air from the heat exchanger and pump when water is added.

[0009] Furthermore, it also includes a level tube, in which the level sensing unit is installed, and the level tube is connected to the inner tank.

[0010] Optionally, it also includes a heat-conducting sheet and a temperature control switch. The two ends of the heat-conducting sheet are respectively thermally coupled to the instant heating unit and the heat storage heating unit or the inner liner, and the temperature control switch is installed on the heat-conducting sheet.

[0011] Optionally, it also includes a flow regulating valve, which is installed on the circulating heat exchange channel. The control unit controls the opening degree of the flow regulating valve to control the flow rate, thereby controlling the outlet water temperature of the water heater.

[0012] Optionally, the pump is located at the outlet end of the heat exchanger.

[0013] A control method, the control method comprising:

[0014] Obtain one or more of the following information: the water heater's operating mode, temperature, and water flow status;

[0015] Determine whether the pump needs to be started based on the obtained parameters;

[0016] If so, the outlet water temperature is controlled by controlling the pump flow rate;

[0017] If not, the outlet water temperature is controlled by adjusting the power of the instant heating unit.

[0018] Optionally, the water heater parameters include one or more of the following: operating mode, water flow switch status, inlet water temperature, inner tank temperature, and outlet water temperature, and the control method includes the following steps:

[0019] Step 1: Obtain the water heater's operating mode. If it is instantaneous mode, proceed to step 2; if it is rapid heating mode, proceed to step 9.

[0020] Step 2: Has the flow switch been activated? If yes, proceed to step 3; if no, proceed to step 22.

[0021] Step 3: Has the instant heating unit been activated? If yes, proceed to step 5; if no, proceed to step 4.

[0022] Step 4: Start the instant heating unit, then proceed to step 5;

[0023] Step 5: Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 6; if no, proceed to step 7.

[0024] Step 6: Increase the power of the instant heating unit, and then perform step 1;

[0025] Step 7: Is the outlet water temperature higher than the set outlet water temperature? If yes, proceed to step 8; if no, proceed to step 1.

[0026] Step 8: Reduce the power of the instant heating unit, and then perform step 1;

[0027] Step 9: Is the flow switch activated? If yes, proceed to step 10; if no, proceed to step 18.

[0028] Step 10: Is the inner tank temperature greater than the inlet water temperature plus 'a'? If yes, proceed to step 11; if no, proceed to step 3.

[0029] Step 11: Is the instant heating unit working? If yes, proceed to step 13; if no, proceed to step 12.

[0030] Step 12: The pump and instant heating unit start working, then proceed to step 13;

[0031] Step 13: Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 14; if no, proceed to step 15.

[0032] Step 14: Increase the pump flow rate, then perform step 1 again;

[0033] Step 15: Is the outlet water temperature higher than the set outlet water temperature? If yes, proceed to step 16; if no, proceed to step 1.

[0034] Step 16: Has the pump been started? If yes, proceed to step 17; if no, proceed to step 8.

[0035] Step 17: Reduce the pump flow rate, then perform step 1 again;

[0036] Step 18: Stop the pump and the instant heat pump, then proceed to step 19;

[0037] Step 19: Is the inner tank temperature lower than the set inner tank temperature? If yes, proceed to step 20; if no, proceed to step 21.

[0038] Step 20: The heat storage and heating unit starts working, then proceed to step 1;

[0039] Step 21: The heat storage and heating unit stops working, then proceed to step 1;

[0040] Step 22: The instant heating unit stops working, then proceed to step 1.

[0041] Beneficial effects

[0042] The water heater and control method disclosed in this application are more hygienic, energy-saving, convenient, aesthetically pleasing and safer than traditional electric storage water heaters; they have lower requirements for wiring and better installation adaptability than instantaneous water heaters, and can handle a larger volume of water; and they achieve a constant temperature effect by adjusting the heat exchange flow rate, which is a brand-new way of water heater temperature control, more stable and durable than traditional thermostatic valves, and has great potential for promotion. Attached Figure Description

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] Figure 1 A schematic diagram of the structure of a water heater Figure 1

[0045] Figure 2 A schematic diagram of the structure of a water heater Figure 2

[0046] Figure 3 A schematic diagram of the structure of a water heater Figure 3

[0047] Figure 4 A schematic diagram of the structure of a water heater Figure 4

[0048] Figure 5 A schematic diagram of the structure of a water heater Figure 5

[0049] Figure 6 A flowchart of a control method

[0050] Figure 7 A logic diagram of a control method.

[0051] In the picture:

[0052] 1. Outer shell 2. Inner tank 3. Instant heating unit 4. Heat storage heating unit 5. Heat exchanger 501. Heat exchanger shell 502. Heat exchange tube 6. Pump 7. Control unit 8. Flow switch 9. Temperature sensor 10. Liquid level sensing unit 11. Water inlet valve 12. Circulating water inlet pipe 13. Circulating water outlet pipe 14. Water inlet end 15. Water outlet end 16. Flow regulating valve 17. Insulation layer 18. Liquid level pipe 19. Vent 20. Connecting pipe 21. Heat-conducting plate 22. Temperature control switch Detailed Implementation

[0053] It should be noted that, without conflict, the embodiments and features described in this application can be combined with each other. The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0054] Example 1

[0055] A water heater includes a shell 1, an inner tank 2, an instant heating unit 3, a heat storage heating unit 4, a flow switch 8, a control unit 7, a temperature sensor 9, an inlet 14, and an outlet 15. It also includes a heat exchanger 5 and a pump 6. The inlet, heat exchanger, instant heating unit, and outlet are connected sequentially to form an instant heating channel. The heat exchanger, pump, and inner tank are connected to form a circulating heat exchange channel. The heat storage heating unit heats the heat storage medium in the inner tank. The control unit controls the operating status of the instant heating unit, heat storage heating unit, and pump according to one or more of the water heater's operating mode, water flow state, and temperature. The control unit includes a speed control module, which controls the pump speed according to the water heater's temperature parameters to adjust the outlet water temperature.

[0056] like Figure 1As shown, tap water enters the water heater from the inlet 14, flows sequentially through the flow switch 8, heat exchanger 5, and instant heating unit 3, and then flows out from the outlet 15 after being heated by the instant heating unit. This path is the instant heating channel. Compared with ordinary instant water heaters, this part only has an additional heat exchanger at the front end of the instant heating unit. The heat storage medium in the inner tank 2 enters from the circulating inlet pipe 12 under the drive of the pump 6, flows through the heat exchanger 5, transfers heat to the tap water in the instant heating channel, and then returns to the inner tank 2 through the pump 6 and the circulating outlet pipe. This heat exchange cycle is equivalent to preheating the cold water. Because the temperature of the heat storage medium decreases and its density decreases after heat exchange, it will sink to the bottom after entering the inner tank from the circulating outlet pipe 13, pushing the hot heat storage medium upwards. In this way, the temperature of the heat storage medium flowing into the circulating inlet pipe will remain relatively stable for a certain period of time. This external circulation heat exchange is far superior to a structure where the heat exchanger is installed directly inside the inner tank. While installing the heat exchanger directly inside the tank eliminates the need for a pump, it causes a continuous drop in the inner tank temperature, leading to unstable outlet water temperature. Even with a thermostatic valve, temperature control becomes relatively difficult. Furthermore, due to the temperature difference, the water flowing out of the heat exchanger is always colder than the heat exchange medium inside the tank, sometimes by tens of degrees Celsius without forced convection. When the water flow stops, the heat storage medium in the inner tank has ample time to bring the water in the heat exchanger to the same temperature. When the user turns on the shower at this point, a stream of extremely hot water comes out, resulting in a very unpleasant experience and a risk of scalding. Finally, because the tap water in the heat exchanger eventually reaches the same temperature as the heat storage medium in the inner tank, scale buildup occurs in the flow channels of the heat exchanger, quickly rendering it unusable. Figure 1 With the internal and external circulation heat exchange method, none of the above problems exist. When the water is turned off, the temperature of the heat medium in the heat exchanger is generally maintained below 50 degrees Celsius after the temperature of the tap water and the cold water is averaged. Moreover, the heat exchanger will also dissipate heat to the outside, so the conditions for scaling will not be met. Figure 1 Pump 6 is installed at the outlet end of the heat exchanger to ensure that the heat storage medium flowing through the pump is a low-temperature medium after releasing heat. Pump 6 is also installed at the inlet end of the heat exchanger 5, which is within the scope of this invention, but this installation method subjectes the pump to high temperatures, which is detrimental to the high-speed rotating impeller, magnets, and electronic components. The temperature of the heat storage medium in the inner tank drops significantly after releasing heat energy through the heat exchanger 5. A high-performance heat exchanger can reduce the temperature of the hot water to only a few degrees higher than the cold water inlet of the water heater. Therefore, installing the pump at the outlet end of the heat exchanger 5 is a better approach. The heat storage and heating unit 4 is installed in the inner tank 2 to heat the heat storage medium in the inner tank. The heat storage medium can be water, oil, or other liquids. Temperature sensors 9 are installed on the outlet end 15 and in the inner tank 2 to sense the temperature of the inner tank and the outlet water. The flow switch 8 can be installed at any position in the entire instant heating channel, such as on the outlet end 15, to sense the water flow status. Figure 1As shown by the dotted line, the water flow switch, temperature sensor, pump, instant heating unit, and heat storage heating unit are connected to the control unit 7 via wires. In special cases, some components can also be wirelessly connected using electromagnetic waves and mechanical waves. The control unit intelligently controls the pump, instant heating unit, and heat storage heating unit as actuators based on the working mode, water flow status, and temperature parameters set by the water heater.

[0057] The inner tank 2 can be either pressurized or non-pressurized. If pressurized, a pressure relief device must be installed; if non-pressurized, it needs an opening to connect to the atmosphere. Both pressurized and non-pressurized inner tanks can be filled with the heat storage medium manually or automatically. Manual filling can be achieved by opening a filling hole in the inner tank and injecting the medium through it; alternatively, a manual valve can be installed, with one end connected to the inner tank and the other to the tap water supply. The valve is manually opened for filling and closed after visual inspection. Automatic filling can be achieved by installing a solenoid valve or a stepper motor-driven valve between the tap water supply and the inner tank, controlled by the control unit 7. Automatic filling can only use tap water as the heat storage medium. The heat storage and heating unit 4 can be a resistance heater or an electromagnetic heater. The resistance heater can be installed inside the inner tank 2 to directly heat the heat storage medium, such as using an electric heating element, or it can be attached to the outer wall of the inner tank for indirect heating, such as using a cast aluminum heating plate. The electromagnetic induction coil of the electromagnetic heating device can only be located outside the inner tank.

[0058] Figure 1 The water heater can have at least two heating modes: instant heating mode and rapid heating mode. In instant heating mode, neither the heat storage heating unit 4 nor the pump 6 works. The cold water entering the water heater does not gain heat through the heat exchanger; it is heated only by the instant heating unit 3. The control unit 7 can control the power of the instant heating unit to adjust the outlet water temperature. In rapid heating mode, the heat storage heating unit 4 heats the heat storage medium in the inner tank. When the water flow switch 8 senses water flow, the pump 6 starts, drawing the heat storage medium from the inner tank and preheating the tap water flowing through the heat exchanger 5. The preheated tap water is then reheated by the instant heating unit 3 before flowing out. Rapid heating mode is used when the tap water temperature is too low for the instant heating mode to meet bathing requirements. These two heating modes combine the advantages of storage-type and instantaneous water heaters. When the tap water temperature is high, the heat storage medium in the inner tank does not need to store heat, allowing for immediate use and avoiding heat loss associated with storage-type water heaters. When the tap water temperature is low, the heat stored in the inner tank can be utilized, enabling the instantaneous heating unit to achieve a large volume of water for bathing with only a low power, thus solving the problem of high power and low water volume in instantaneous water heaters. At the same time, since the instantaneous heating unit with appropriate power plays a dominant role, the capacity of the inner tank can be greatly reduced. Its capacity is only needed to assist the instantaneous heating when the tap water temperature is low, making the water heater more aesthetically pleasing, heating up quickly, and allowing multiple people to take turns bathing.

[0059] Scale buildup in storage water heaters is a major industry problem. Large amounts of scale accumulate in the inner tank, significantly impacting water hygiene and the lifespan of the heating element. It also increases energy consumption, reduces the effective capacity of the water heater, and brings various adverse effects. Figure 1 The heat exchange structure adopted in this invention effectively solves this problem: 1. The inner tank 2 and the heat storage and heating unit 4 will not produce scale. Even if well water with severe scale is used as the heat storage medium in a 30-liter water heater using this invention, since the water in the inner tank is not discharged for use but is only used as a heat storage medium, after filling, only the amount of water evaporated needs to be replenished. During its lifespan of about 8 years, the amount of water entering the inner tank is expected to be around 80 liters, which is comparable to the amount of scale produced by a regular 80-liter water storage tank after one use, and can be ignored; 2. The heat exchanger 5 is also difficult to form scale. The heat storage medium flowing through the heat exchanger from the inner tank has a high temperature, but for the same reason as the inner tank, the scale is negligible; the tap water flowing through the heat exchanger has a low temperature and a fast flow rate, which does not meet the conditions for scale formation; 3. If the instant heating unit 3 uses a cast aluminum heater, based on more than ten years of experience in the instant water heater industry, it will not produce scale. Heat exchange methods are commonly used in water heaters, such as in multi-mode water heaters. However, because the heat exchanger is placed inside the inner tank, scale buildup inside the heat exchange tubes can cause the heat exchanger to lose its heat exchange function or even become blocked. Furthermore, placing the heat exchanger inside the inner tank can lead to scalding water when the water is turned off and then on again, severely impacting the user experience. Even with a thermostatic valve, the temperature stabilization process is prolonged, resulting in a poor experience. The heat exchanger's placement inside the inner tank causes a continuous drop in the overall tank temperature, leading to a continuous drop in the water outlet temperature, requiring frequent adjustments to the hot and cold water mixing ratio. It also makes maintenance inconvenient. This invention places the heat exchanger outside the inner tank. Although it adds a pump, it completely solves the above problems. Moreover, the water outlet temperature can be controlled by adjusting the pump flow rate, eliminating the need for a thermostatic valve. The increased pump cost offsets the cost of the thermostatic valve, making this solution extremely cost-effective.

[0060] Pump 6 can be an adjustable-speed pump or a regular non-adjustable pump. If it is not adjustable, the water temperature cannot be controlled by adjusting the flow rate, or the flow rate of the heat storage medium must be adjusted by adding a flow regulating valve to control the water temperature. Of course, in the quick-heating mode, the water temperature can be adjusted by controlling the power of the instant heating unit 3 or the flow rate of the tap water, without relying on adjusting the pump flow rate. However, this method will reduce the hot water output of the water heater because the power of the instant heating unit cannot be fully utilized; or it may not be adaptable to different water pressures. For example, if a suitable pump flow rate is fixed, when the user's tap water pressure is high, the tap water flow rate is large. Even after the tap water has undergone heat exchange and is heated to full power by the instant heating unit, it cannot reach the set water temperature. In this case, the user only needs to manually reduce the flow rate. The same situation applies when there are multiple water supply points. If the pump can adjust the flow rate, then only the pump flow rate needs to be increased. Therefore, when the heat exchanger needs to preheat the tap water in the quick-heating mode, it is a better solution to control the water outlet temperature of the water heater by adjusting the pump flow rate. This allows the instant heating unit 3 to operate at its maximum power. At this time, under a certain flow rate and water outlet temperature, the flow rate of the heat storage medium pumped out of the inner tank is the minimum, resulting in a longer water usage time and the maximum hot water output.

[0061] Example 2

[0062] The inner liner of this embodiment is connected to the atmosphere and also includes a liquid level sensing unit 10 and a water inlet valve 11. The liquid level sensing unit is installed on the inner liner or a component connected to the inner liner and is used to sense the liquid level in the inner liner. The inner liner is connected to the instant heating channel through the water inlet valve. It also includes a heat-conducting plate 21 and a temperature control switch 22. The two ends of the heat-conducting plate are thermally coupled to the instant heating unit 3 and the heat storage heating unit 4 or the inner liner 2, respectively. The temperature control switch is installed on the heat-conducting plate.

[0063] like Figure 2 As shown, an exhaust vent 19 is added to the inner liner 2 to communicate with the atmosphere. A liquid level sensing unit 10 is set on the top of the inner liner to sense the liquid level of the heat storage medium in the inner liner. By transmitting a signal to the control unit 7, it can play one or more roles such as prompting, controlling automatic water replenishment and preventing dry burning. Figure 2In this system, one end of the water inlet valve 11 is connected to the water inlet 14, and the other end is connected to the heat exchanger 5. The connection point with the heat exchanger should be chosen to facilitate the removal of air from the heat exchanger and pump 6. If there is too much air, the pump 6 may be unable to draw the heat storage medium from the inner tank. The purpose of the water inlet valve 11 is to add water to the inner tank 2. It can be a manual valve or an automatic valve. If a manual valve is used, when the liquid level sensing unit 10 senses that the liquid level is too low, it can prompt the user to add water through sound or light. If an automatic valve is used, when the liquid level sensing unit 10 senses that the liquid level is too low, the water inlet valve 11 will automatically add water and automatically shut off when full. The water inlet valve can be installed by simply connecting the inner tank to the tap water supply. However, if it is connected to the back end of the water flow switch 8, the water flow switch will also sense water flow when the inner tank is being filled, causing confusion with the user's water usage. If the instant heating unit starts at this time, it will lead to dry burning. This problem can be avoided through software design, for example, by having the instant heating unit not work when the liquid level sensing unit senses a low liquid level.

[0064] like Figure 2 As shown, heat exchanger 5 includes a heat exchanger shell 501 and heat exchange tubes 502, and is a shell-and-tube heat exchanger. This type of heat exchanger has a simple structure and low cost, but its heat exchange efficiency is poor due to laminar flow, making it inferior to shell-and-tube heat exchangers. However, shell-and-tube heat exchangers are more expensive and also have low heat exchange efficiency due to laminar flow, although they are much better than the heat exchanger shown in the figure. Considering performance, economy, and structural compactness, plate heat exchangers can be selected. The schematic diagram of this invention is only for simplicity and clarity, so the simplest shell-and-tube heat exchanger is used as a schematic diagram and should not be taken as a limitation of this invention.

[0065] like Figure 3 As shown, it also includes a liquid level tube 18, in which the liquid level sensing unit 10 is installed, and the liquid level tube is connected to the inner tank 2. This structure allows the liquid level sensing unit to avoid being subjected to the high temperature of the inner tank, resulting in better component reliability and a longer lifespan. Figure 3 The liquid level sensor in this system uses a float switch, which utilizes a magnet acting on a reed switch or Hall effect switch to detect the liquid level. These float switches achieve electrical isolation and meet the protection requirements of Class II electrical appliances. However, float switches may experience problems such as float jamming, reed switch or Hall effect element failure, and magnet demagnetization. If the liquid level sensor uses... Figure 4 Electrode induction is simpler and more reliable than float switches, but its disadvantage is the potential risk of leakage. Although the electrodes use a few volts of low voltage, there is still a risk of leakage due to transformer damage, bridging of strong and weak currents, or lightning strikes. Figure 4 In the middle, a slender and insulated connecting tube 20 is added, so that a sufficiently large resistor made of heat storage medium is connected in series between the inner tank and the liquid level sensing unit, so that even if the liquid level sensing unit 10 is charged with a voltage of 220 volts, it will not pose a safety hazard to the user.

[0066] like Figure 2 As shown, the water heater of this invention includes two heating elements: an instant heating unit and a storage heating unit. For safety reasons, electronic components may fail, and relay contacts may spark and become soldered shut, leading to temperature control failure. Therefore, each heating element or the associated inner tank needs to be equipped with a manually reset mechanical temperature control switch to prevent uncontrolled heating, serving as a last resort in case of electronic component failure. However, installing two temperature control switches not only increases costs but also multiplies the failure rate. Therefore, as... Figure 2 As shown, two heaters are directly or indirectly connected using a heat-conducting plate 21. A temperature control switch 22 is mounted on the heat-conducting plate, so that if either of the two heating units gets too hot, the temperature control switch will provide protection. Of course, one end of the heat-conducting plate connected to the heat storage and heating unit 4 can also be connected to the inner liner, as long as the temperature transfer is good.

[0067] Figure 2 A temperature sensor 9 is installed on the water inlet 14 to sense the temperature of the incoming tap water. Based on the incoming water temperature, the water heater can automatically determine whether to use instant or fast heating mode, how many degrees the inner tank temperature should be heated, and whether the pump should be started, thereby achieving more intelligent control.

[0068] like Figure 5 As shown, it also includes a flow regulating valve 16, which is installed on the circulating heat exchange channel. The control unit controls the opening degree of the flow regulating valve to control the pump flow rate, thereby controlling the water outlet temperature of the water heater. When adjusting the flow rate by the speed regulating pump is inaccurate or uneconomical, a valve can be used to regulate the flow rate, thereby achieving the purpose of regulating the outlet water temperature.

[0069] Example 3

[0070] The water heaters in the two embodiments described above require a new control method to better leverage the technological advantages brought about by the structural innovation. This embodiment introduces such a control method. It should be noted that the control method in this invention only addresses the control of the structural innovation portion of the invention and does not include a complete control method for the water heater. Figure 6 As shown, the control method includes, but is not limited to, the following steps:

[0071] Obtain one or more of the following information: the water heater's operating mode, temperature, and water flow status;

[0072] Determine whether the pump needs to be started based on the obtained parameters;

[0073] If so, the outlet water temperature is controlled by controlling the pump flow rate;

[0074] If not, the outlet water temperature is controlled by adjusting the power of the instant heating unit.

[0075] The water heater operating modes of this invention can include intelligent mode, instant heating mode, and fast heating mode. Intelligent mode automatically selects between instant heating mode and fast heating mode based on the inlet water temperature and automatically sets the temperature of the inner tank. Figure 7 The intelligent mode was not displayed.

[0076] The following provides a more specific control method. The portion concerning liquid level control is outside the scope of this invention, so control methods for liquid level control and low liquid level protection are omitted. For example... Figure 7 As shown, Tn is the actual temperature of the inner tank, Tns is the set temperature of the inner tank, Tc is the actual outlet water temperature, Tcs is the set outlet water temperature, Tj is the inlet water temperature, and a is any real number.

[0077] S201. After the water heater is powered on, first obtain the water heater's working mode. If it is instant heating mode, then execute S202; if it is fast heating mode, then execute S212.

[0078] S202, Instant heating mode, execute S203;

[0079] S203. Determine if there is water flowing in the water heater. If there is water flowing, proceed to S204. If there is no water flowing, proceed to S205.

[0080] S204. Determine if the instant heating unit is already in operation. If yes, proceed to S207; otherwise, proceed to S206. Since the parameters of the water heater are constantly changing, such as the user adjusting the water heater's operating mode and outlet water temperature during operation, or the tap water suddenly stopping, the program is always in a loop. When the parameters change, it can react in time. Step S204 is to determine whether it is the first loop after the water heater has just turned on or a subsequent loop. If it is the first loop, the instant heating unit needs to be activated. If it is a subsequent loop, it is only necessary to consider whether the power needs to be adjusted to make the outlet water temperature close to the set outlet water temperature.

[0081] S205, stop the instant heating unit from working, and then execute S208; if the instant heating unit was originally in the off state, then keep it in the off state.

[0082] S206. Start the instant heating unit, and then execute S207;

[0083] S207. Compare whether the actual outlet water temperature is lower than the outlet water set temperature. If so, execute S209 to increase the power of the instant heating unit; otherwise, execute S210 to compare whether the actual outlet water temperature is higher than the outlet water set temperature.

[0084] S208, Execute S201, return to the beginning of the program and start the next loop;

[0085] S209. Increase the power of the instant heater. The amount of increase depends on the actual test results and is also related to the time interval between the two cycles of the program. In short, the thermal lag problem must be taken into account. After the heater adjusts its power, it will take a certain amount of time to reflect the water temperature. Therefore, if the cycle speed is fast, the wattage of the power should be adjusted low each time. Otherwise, the water temperature will be hot and cold and will never be adjusted to the correct temperature.

[0086] S210. Compare whether the actual outlet water temperature is greater than the set outlet water temperature. If yes, execute S211 to reduce the power of the instant heating unit. If not, execute S228. In S207, it was already compared whether it was less than. In S210, it was compared whether it was greater than. If both are no, then it must be equal to, which proves that the current actual outlet water temperature is equal to the set outlet water temperature. There is no need to adjust the power of the instant heating unit.

[0087] S211, reduce the power of the instantaneous heating unit, and then execute S228;

[0088] S212, Quick Heating Mode, execute S213; The so-called quick heating mode is a working mode in which the inner tank of the water heater stores heat to provide auxiliary heat to the instant heating unit.

[0089] S213. Determine if there is water flow in the water heater. If there is water flow, execute S215. If there is no water flow, execute S214.

[0090] S214. Turn off the pump and the instant heating unit; if the pump and the instant heating unit were already in the off state, keep them in the off state, and then execute S217.

[0091] S215. Determine if the inner tank temperature is greater than the inlet water temperature plus 'a'. If yes, proceed to S218; otherwise, proceed to S216. The inner tank temperature must be slightly higher than the inlet water temperature for heat exchange to be meaningful. The exact difference depends on the heat exchanger's performance, so 'a' can be determined based on actual test data. If the inner tank temperature is too low, heat exchange is meaningless, so even in fast-heating mode, the pump will not start. In this case, the instant-heating mode program can be called to control the water heater's operation.

[0092] S216, Execute S204;

[0093] S217. Determine if the inner tank temperature is lower than the set inner tank temperature. If yes, execute S224; otherwise, execute S221. In the actual control program, 'a' should be added to determine if the inner tank temperature is lower than the set inner tank temperature. Otherwise, it will lead to frequent heating, such as heating only when the inner tank temperature is set to 80 degrees Celsius and then dropping below 75 degrees Celsius. This control method only provides the control logic of the water heater based on this invention and does not involve the details of the actual program.

[0094] S218. Determine if the instant heating unit is already in operation. If yes, proceed to S220; otherwise, proceed to S219. If the instant heating unit is not started in this step, it proves that the program is in the first cycle after the water flow is turned on. At this time, the pump must also not be started. If the instant heating unit has started in this step, it proves that it is no longer the first cycle. At this time, you only need to consider whether the outlet water temperature is equal to the outlet water setting temperature.

[0095] S219. Starting the pump and the instant heating unit: Generally, in rapid heating mode, the instant heating unit operates at its set maximum power upon startup. This set maximum power is the power level set by the user; for example, some users may set a lower power level due to concerns about circuit load. If no power setting is specified, the rated power, i.e., the maximum power of the water heater, is used. Of course, considering operating at the maximum set power upon startup is solely for increasing hot water output. The goal is to have the instant heating unit operate at maximum power, and by adjusting the pump flow rate to regulate the outlet water temperature, the amount of heat drawn from the inner tank is minimized, thus extending the usage time. If hot water output is not a concern, this consideration is unnecessary, and the pump flow rate does not need to be adjusted. In rapid heating mode, the outlet water temperature is regulated by adjusting the power of the instant heating unit. Even maintaining a constant outlet water temperature is not required; the user can adjust the water flow rate or the hot and cold water ratio themselves, all of which are within the scope of this invention. This control method merely provides a preferred solution.

[0096] S220. Determine if the outlet water temperature is lower than the set outlet water temperature. If yes, execute S223 to increase the pump flow rate; if no, execute S222.

[0097] S221. Turn off the heat storage and heating unit, and then execute S228;

[0098] S222. Determine if the outlet water temperature is greater than the outlet water setting temperature. If yes, execute S225; if no, execute S228. If the results of the comparisons in steps S220 and S222 are both no, then the actual outlet water temperature must be equal to the outlet water setting temperature. The program does not need to perform temperature adjustment and can directly return to the next loop.

[0099] S223, increase the pump flow rate, and then execute S228; the amount of increase or decrease in the pump flow rate each time should also be determined according to the speed of the program cycle, otherwise the outlet water temperature will fluctuate due to the thermal feedback delay of the heat exchange system and temperature sensor, and will never be stable.

[0100] S224. Start the heat storage and heating unit; starting the heat storage and heating unit is to heat the heat storage medium of the inner liner.

[0101] S225. Determine if the pump has started. If yes, execute S227 to reduce the pump flow rate; if no, execute S226 to reduce the power of the instant heating unit. The purpose of this step is that if the pump flow rate has been turned off but the outlet water temperature is still high, the outlet water temperature can only be controlled by reducing the power of the instant heating unit.

[0102] S226, Execute S211;

[0103] S227. Reduce the pump flow rate;

[0104] S228, Execute S201.

[0105] The control methods described above are just one of many available control methods; others can be based on... Figure 6 The flowchart design, as well as other specific control methods, are all within the scope of protection of this invention.

[0106] The above examples do not exhaust all structures and methods. All combinations of the above solutions, any solutions that can be easily conceived through this invention, and any modified solutions are all within the scope of protection of this patent.

Claims

1. A water heater, comprising a shell (1), an inner tank (2), an instant heating unit (3), a heat storage heating unit (4), a flow switch (8), a control unit (7), a temperature sensor (9), a water inlet (14), and a water outlet (15), characterized in that: It also includes a heat exchanger (5) and a pump (6). The water inlet, heat exchanger, instant heating unit and water outlet are connected in sequence to form an instant heating channel. The heat exchanger, pump and inner tank are connected to form a circulating heat exchange channel. The heat storage heating unit is used to heat the heat storage medium in the inner tank. The control unit controls the working status of the instant heating unit, heat storage heating unit and pump according to one or more of the water heater working mode, water flow state and temperature. The control unit (7) includes a speed control module. The control unit controls the pump speed according to the water heater temperature parameters to adjust the outlet water temperature.

2. A water heater according to claim 1, characterized in that: The inner liner is connected to the atmosphere and also includes a liquid level sensing unit (10) and a water inlet valve (11). The liquid level sensing unit is installed on the inner liner or a component connected to the inner liner and is used to sense the liquid level in the inner liner. The inner liner is connected to the instant heating channel through the water inlet valve.

3. A water heater according to claim 2, characterized in that: The water inlet valve (11) is connected to the inner tank through a heat exchanger and is used to remove air from the heat exchanger and pump when water is added.

4. A water heater according to claim 2, characterized in that: It also includes a level tube (18), in which the level sensing unit is installed and the level tube is connected to the inner liner (2).

5. A water heater according to claim 1, characterized in that: It also includes a heat-conducting sheet (21) and a temperature control switch (22). The two ends of the heat-conducting sheet are thermally coupled to the instant heating unit (3) and the heat storage heating unit (4) or the inner liner (2), respectively. The temperature control switch is installed on the heat-conducting sheet.

6. A water heater according to claim 1, characterized in that: It also includes a flow regulating valve (16), which is installed on the circulating heat exchange channel. The control unit controls the opening degree of the flow regulating valve to control the flow rate, thereby controlling the outlet water temperature of the water heater.

7. A water heater according to claim 1, characterized in that: The pump (6) is located at the outlet end of the heat exchanger (5).

8. A control method for a water heater according to any one of claims 1 to 7, characterized in that: The control method includes: Obtain one or more of the following information: the water heater's operating mode, temperature, and water flow status; Determine whether the pump needs to be started based on the obtained parameters; If so, the outlet water temperature is controlled by controlling the pump flow rate; If not, the outlet water temperature is controlled by adjusting the power of the instant heating unit.

9. The control method according to claim 8, characterized in that: The water heater parameters include one or more of the following: operating mode, water flow switch status, inlet water temperature, water tank temperature, and outlet water set temperature. Its control method includes the following steps: Step 1: Obtain the water heater's operating mode. If it is instantaneous mode, proceed to step 2; if it is rapid heating mode, proceed to step 9. Step 2: Has the flow switch been activated? If yes, proceed to step 3; if no, proceed to step 22. Step 3: Has the instant heating unit been activated? If yes, proceed to step 5; if no, proceed to step 4. Step 4: Start the instant heating unit, then proceed to step 5; Step 5: Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 6; if no, proceed to step 7. Step 6: Increase the power of the instant heating unit, and then perform step 1; Step 7: Is the outlet water temperature higher than the set outlet water temperature? If yes, proceed to step 8; if no, proceed to step 1. Step 8: Reduce the power of the instant heating unit, and then perform step 1; Step 9: Is the flow switch activated? If yes, proceed to step 10; if no, proceed to step 18. Step 10: Is the inner tank temperature greater than the inlet water temperature plus 'a'? If yes, proceed to step 11; if no, proceed to step 3. Step 11: Is the instant heating unit working? If yes, proceed to step 13; if no, proceed to step 12. Step 12: The pump and instant heating unit start working, then proceed to step 13; Step 13: Is the outlet water temperature lower than the set outlet water temperature? If yes, proceed to step 14; if no, proceed to step 15. Step 14: Increase the pump flow rate, then perform step 1 again; Step 15: Is the outlet water temperature higher than the set outlet water temperature? If yes, proceed to step 16; if no, proceed to step 1. Step 16: Has the pump been started? If yes, proceed to step 17; if no, proceed to step 8. Step 17: Reduce the pump flow rate, then perform step 1 again; Step 18: Stop the pump and the instant heat pump, then proceed to step 19; Step 19: Is the inner tank temperature lower than the set inner tank temperature? If yes, proceed to step 20; if no, proceed to step 21. Step 20: The heat storage and heating unit starts working, then proceed to step 1; Step 21: The heat storage and heating unit stops working, then proceed to step 1; Step 22: The instant heating unit stops working, then proceed to step 1.

Images