Double-tank hot water system and control method thereof

Abstract

The application discloses a double-water-tank hot water system and a control method thereof. The double-water-tank hot water system comprises a heat preservation water tank, a heating water tank and a heat pump unit. The water outlet side of the heat preservation water tank is connected to a user end through a second pump set. A pressure difference water supplement pipe with controllable on-off state is connected between the heating water tank and the heat preservation water tank. The heating water tank is further connected to an external water supplement pipe. The water inlet side of the heat pump unit is connected to the water outlet side of the heating water tank through a first pump set. The water outlet side of the heat pump unit is switchably connected to the water inlet side of the heating water tank and / or the water inlet side of the heat preservation water tank. The heat pump unit is designed at the water outlet side of the heating water tank. The connection state of the water outlet side of the heat pump unit is switched to realize heating or water supplement to the heating water tank and the heat preservation water tank. The system structure is simplified, the condensing temperature of the heat pump unit is reduced, and the operation energy efficiency of the hot water system is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot water systems, in particular to a double-tank hot water system and a control method thereof. BACKGROUND

[0002] Centralized hot water systems are widely used in schools, office buildings, breeding and other scenarios. Traditional centralized hot water systems use fossil fuel combustion or electric heating to produce hot water. Such methods are high in energy consumption and polluting. With the consensus on energy saving and carbon reduction, more new heat sources are used in the hot water field, including solar energy, soil energy and air energy, which are excellent in energy saving and environmental protection. Solar energy has regional differences and instability, and soil energy has harsh use conditions, so its widespread use is limited. Air source heat pump, as a new type of heat source that can stably produce heat and has higher energy efficiency than traditional heat sources by 2-3 times, is widely used.

[0003] There are design schemes in the prior art that can improve the operating energy efficiency of air source hot water systems. For example, the patent application with publication number CN112665183A discloses an air source heat pump double-tank hot water system and a control method thereof. According to the water demand of the system at different times of the year, the number of heat pump units put into use is adjusted to improve the system energy efficiency. However, this hot water system needs to be equipped with multiple air source heat pump units, the pipeline connection is complex, the cost is high, and the energy consumption of the whole machine is high when multiple units work at the same time, so there is still room for improvement in system energy efficiency.

[0004] Therefore, how to design a double-tank hot water system with simple pipeline connection and higher operating energy efficiency and a control method thereof is a technical problem that needs to be solved in the industry. SUMMARY

[0005] To solve the problems of complex connection and low energy efficiency of existing hot water systems, the present application proposes a double-tank hot water system and a control method thereof. The heat pump unit is designed on the outlet side of the heating tank, and the outlet side connection state of the heat pump unit is switched to heat or supplement the heating tank and the insulation tank. This simplifies the system structure and reduces the condensing temperature of the heat pump unit, effectively improving the operating energy efficiency of the hot water system.

[0006] The technical solution adopted by the present application is to design a double-tank hot water system, which includes an insulation tank, a heating tank and a heat pump unit. The outlet side of the insulation tank is connected to the user end through a second pump group. A pressure difference water supplement pipe with controllable on-off state is connected between the heating tank and the insulation tank. The heating tank is also connected to an external water supplement pipe. The inlet side of the heat pump unit is connected to the outlet side of the heating tank through a first pump group. The outlet side of the heat pump unit can be switched to connect the inlet side of the heating tank and / or the inlet side of the insulation tank.

[0007] Further, the heating water tank is provided with a heating water inlet pipe, the heat preservation water tank is provided with a heat preservation water inlet pipe, and the water outlet side of the heat pump unit is provided with a liquid supply pipe, the heating water inlet pipe and the heat preservation water inlet pipe are connected to the liquid supply pipe.

[0008] Further, the water outlet side of the heat preservation water tank is provided with a water return pipe, the outlet of the water return pipe is connected to the inlet of the heat preservation water inlet pipe, and the liquid supply pipe and the water return pipe are respectively provided with check valves that only allow liquid to flow to the heat preservation water inlet pipe.

[0009] Further, each pump group comprises two water pumps arranged in parallel.

[0010] The application further provides a control method of the double water tank hot water system, which is applied to the double water tank hot water system and comprises the following steps of:

[0011] detecting the actual water temperature t2 and the actual liquid level w1 of the heat preservation water tank;

[0012] determining whether the actual water temperature t2 of the heat preservation water tank is lower than a set heat preservation lower limit temperature t 2,0 or the actual liquid level w1 of the heat preservation water tank is lower than a set heat preservation lower limit liquid level w 1,0 .

[0013] If yes, a hot water supplement action is performed, the pressure difference water supplement pipe is turned on, the water outlet side of the heat pump unit is connected to the heat preservation water tank, the first pump group is started, and the heat pump unit is controlled to be started or stopped according to the working parameters of the heating water tank.

[0014] Further, the control of the heat pump unit to be started or stopped according to the working parameters of the heating water tank comprises the following steps of:

[0015] detecting the actual liquid level w2 and the actual water temperature t1 of the heating water tank;

[0016] determining whether the actual liquid level w2 of the heating water tank is higher than a set heating upper limit liquid level w 2,1 and the actual water temperature t1 of the heating water tank is higher than a set heating upper limit temperature t 1,2 .

[0017] If yes, the heat pump unit is stopped;

[0018] If no, the heat pump unit is started.

[0019] Further, the control of the heat pump unit to be started or stopped according to the working parameters of the heating water tank further comprises the following steps of: after the heat pump unit is stopped, determining whether the actual water temperature t2 of the heat preservation water tank is higher than a set heat preservation upper limit temperature t 2,1 and the actual liquid level w1 of the heat preservation water tank is higher than a set heat preservation upper limit liquid level w 1,1 , if no, the hot water supplement action is continuously performed.

[0020] Further, the control method further comprises:

[0021] detecting the actual liquid level w2 and the actual water temperature t1 of the heating water tank after the heat pump unit is started;

[0022] determining whether the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 or the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 .

[0023] if yes, stopping the hot water supplementing action and selecting the heating action and / or the water supplementing action on the heating water tank;

[0024] if no, determining whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit temperature t 2,1 and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit liquid level w 1,1 , if no, continuing the hot water supplementing action.

[0025] Further, the control method further comprises:

[0026] determining whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit temperature t 2,1 and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit liquid level w 1,1 , if yes, controlling the start or stop of the second pump set according to the outlet side working parameter of the heat preservation water tank.

[0027] Further, the control method further comprises:

[0028] detecting the outlet side pipe network pressure p1 of the heat preservation water tank;

[0029] determining whether the outlet side pipe network pressure p1 of the heat preservation water tank is less than the set lower limit pressure p0;

[0030] if yes, starting the second pump set to send water back to the heat preservation water tank until the outlet side pipe network pressure p1 of the heat preservation water tank is greater than or equal to the set upper limit pressure p2, and detecting the outlet side return water temperature t3 of the heat preservation water tank;

[0031] if no, detecting the outlet side return water temperature t3 of the heat preservation water tank;

[0032] wherein, after detecting the outlet side return water temperature t3 of the heat preservation water tank, when the outlet side return water temperature t3 of the heat preservation water tank is greater than or equal to the set return water temperature t 3,0 , the second pump set is stopped to stop sending water back to the heat preservation water tank, and the outlet side pipe network pressure p1 of the heat preservation water tank is detected again.

[0033] Further, the control method further comprises:

[0034] After detecting the return water temperature t3 of the outlet side of the heat preservation water tank, when the return water temperature t3 of the outlet side of the heat preservation water tank is less than the set return water temperature t 3,0 , it is determined whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set lower limit temperature t 2,0 of the heat preservation and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set lower limit liquid level w 1,0 .

[0035] If yes, the second pump group is turned off, the water is stopped from being sent back to the heat preservation water tank, and the outlet side pipe network pressure p1 of the heat preservation water tank is re-detected.

[0036] If no, a hot water supplementing action is performed until the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set upper limit temperature t 2,1 of the heat preservation and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set upper limit liquid level w 1,1 , the second pump group is turned off, the water is stopped from being sent back to the heat preservation water tank, and the outlet side pipe network pressure p1 of the heat preservation water tank is re-detected.

[0037] Further, the selection of performing the heating action and / or the water supplementing action on the heating water tank comprises:

[0038] When the actual liquid level w2 of the heating water tank is less than the set lower limit liquid level w 2,0 of the heating, the water supplementing action is performed, the pressure difference water supplementing pipe is turned off, and the external water supplementing pipe is turned on to supplement water to the heating water tank.

[0039] When the actual water temperature t1 of the heating water tank is less than the set lower limit temperature t 1,0 of the heating, the heating action is performed, the pressure difference water supplementing pipe is turned off, the first pump group and the heat pump unit are turned on, and the outlet side of the heat pump unit is connected to the heating water tank.

[0040] Further, the selection of performing the heating action and / or the water supplementing action on the heating water tank further comprises:

[0041] First, it is determined whether the actual liquid level w2 of the heating water tank is less than the set lower limit liquid level w 2,0 of the heating.

[0042] If yes, the water supplementing action is performed until the actual liquid level w2 of the heating water tank is greater than or equal to the set upper limit liquid level w 2,1 of the heating, it is determined whether the actual water temperature t1 of the heating water tank is less than the set lower limit temperature t 1,0 of the heating, if yes, the heating action is performed until the actual water temperature t1 of the heating water tank is greater than or equal to the set upper limit temperature t 1,2 of the heating, and the actual water temperature t2 and the actual liquid level w1 of the heat preservation water tank are re-detected.

[0043] If not, it is judged whether the actual water temperature t1 of the heating tank is less than the set heating lower limit temperature t 1,0 If not, it returns to re-detect the actual water temperature t2 and the actual liquid level w1 of the heat preservation tank, and if yes, it performs the heating action until the actual water temperature t1 of the heating tank is greater than or equal to the set heating upper limit temperature t 1,2 It returns to re-detect the actual water temperature t2 and the actual liquid level w1 of the heat preservation tank.

[0044] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0045] 1. The heat pump unit is designed at the outlet side of the heating tank, and the outlet side connection state of the heat pump unit is switched to realize heating of the heating tank and the heat preservation tank. When the heat pump unit is started, the outlet water of the heating tank is heated, the condensing temperature of the heat pump unit is reduced, the operation energy efficiency of the hot water system is effectively improved, and the first pump group provides power to completely heat the heating cycle of the heating tank and complete the heating and water replenishment cycle of the heat preservation tank, thereby simplifying the system structure and reducing the production cost of the hot water system.

[0046] 2. The actual water temperature t2 and the actual liquid level w1 of the heat preservation tank are monitored, the hot water replenishment action is performed when the water temperature or the water level is insufficient, the water in the heating tank is replenished into the heat preservation tank through the differential pressure water replenishment pipe and the first pump group, and the start or stop of the heat pump unit is controlled according to the working parameters of the heating tank, so that the heat preservation tank can be quickly and efficiently replenished with hot water.

[0047] 3. The actual liquid level w2 and the actual water temperature t1 of the heating tank are monitored during the process of replenishing hot water into the heat preservation tank, the heating action and / or the water replenishment action are performed when the water temperature or the water level is insufficient, the low-temperature water flowing out of the heating tank is heated by the condensing side of the heat pump unit, the heat exchange temperature difference of the condensing side is increased, efficient heat production management is achieved, hot water is replenished into the heat preservation tank after the water temperature and the water level of the heating tank are in place, the water temperature stability of the heat preservation tank is improved, and the energy efficiency of the hot water system is improved.

[0048] 4. After the hot water amount of the heat preservation tank is sufficient, the working parameters of the outlet side of the heat preservation tank are monitored, and when the outlet side return water temperature t3 drops excessively, the water in the pipe network is pumped into the heat preservation tank and then sent out until the outlet side return water temperature t3 rises, so that instant hot water can be sent out when each user end is used, and the user experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0049] The present application will be described in detail below in conjunction with the embodiments and the drawings, in which:

[0050] Figure 1 is a connection schematic diagram of the hot water system of the present application;

[0051] Figure 2is the operation logic schematic diagram of the heat preservation water tank of the present application;

[0052] Figure 3 is the heating logic schematic diagram of the heating water tank of the present application;

[0053] Figure 4 is the water replenishment logic schematic diagram of the heating water tank of the present application;

[0054] Figure 5 is the operation logic schematic diagram of the outlet side pipe network of the present application;

[0055] BRIEF DESCRIPTION OF DRAWINGS: 1, heating water tank; 2, heat preservation water tank; 3, heat pump unit; 4, user end; 5, external water replenishment pipe; 6, first pump group; 7, second pump group; 8, pressure difference water replenishment pipe; 9, on-off valve; 10, water replenishment valve; 11, liquid supply pipe; 12, heating water inlet pipe; 13, heat preservation water inlet pipe; 14, heating valve; 15, heat preservation valve; 16, backwater pipe; 17, first temperature sensor; 18, first liquid level sensor; 19, second temperature sensor; 20, second liquid level sensor; 21, pressure sensor; 22, third temperature sensor. DETAILED DESCRIPTION

[0056] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects more clearly understood, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0057] As shown in Figure 1 , the double water tank hot water system proposed by the present application comprises: a heating water tank 1, a heat preservation water tank 2 and a heat pump unit 3.

[0058] The water inlet side of the heat pump unit 3 is connected to the water outlet side of the heating water tank 1 through the first pump group 6, and the water outlet side of the heat pump unit 3 can be switchably connected to the water inlet side of the heating water tank 1 and / or the water inlet side of the heat preservation water tank 2. When the first pump group 6 is turned on, the water flowing out of the heating water tank 1 is driven to enter the water inlet side of the heat pump unit 3, and then flows out from the water outlet side of the heat pump unit 3 to the heating water tank 1 and / or the heat preservation water tank 2. The water outlet side of the heat preservation water tank 2 is connected to the user end 4 through the second pump group 7, and the water sent out by the heat preservation water tank 2 can flow to the user end 4.

[0059] A pressure-differential water supply pipe 8 is connected between the heating water tank 1 and the insulated water tank 2. This pipe is equipped with an on / off valve 9 that controls its on / off state. This pipe is typically located below the heating water tank 1 and the insulated water tank 2. When this pipe is connected, the heating water tank 1 and the insulated water tank 2 communicate, and the pressure differential causes the liquid levels in the two tanks to converge. The heating water tank 1 is also connected to an external water supply pipe 5, equipped with an on / off valve 10 that controls its on / off state. The water source for this external water supply pipe 5 includes, but is not limited to, tap water.

[0060] The present invention designs the heat pump unit on the water outlet side of the heating water tank 1, and heats the heating water tank 1 and the insulated water tank 2 by switching the connection state of the water outlet side of the heat pump unit 3. When the heat pump unit 3 is turned on, the outlet water of the heating water tank 1 is heated, the condensing temperature of the heat pump unit 3 is reduced, and the operating energy efficiency of the hot water system is effectively improved. Moreover, the power is provided by the first pump unit 6, which can not only completely complete the heating cycle of the heating water tank 1, but also complete the heating and water replenishment cycle of the insulated water tank 2, simplifying the system structure and reducing the production cost of the hot water system.

[0061] like Figure 1 As shown, specifically, the heating water tank 1 is provided with a heating water inlet pipe 12, the insulated water tank 2 is provided with an insulated water inlet pipe 13, and the water outlet side of the heat pump unit 3 is provided with a liquid supply pipe 11, and the heating water inlet pipe 12 and the insulated water inlet pipe 13 are both connected to the liquid supply pipe 11. Among them, the heating water inlet pipe 12 is installed with a heating valve 14, and the insulated water inlet pipe 13 is installed with an insulated valve 15. The heating valve 14 and the insulated valve 15 are used to switch the connection state of the water outlet side of the heat pump unit 3. When the heating valve 14 is open and the insulated valve 15 is closed, the water outlet side of the heat pump unit 3 is connected to the water inlet side of the heating water tank 1. When the heating valve 14 is closed and the insulated valve 15 is open, the water outlet side of the heat pump unit 3 is connected to the water inlet side of the insulated water tank 2.

[0062] By designing the heating water inlet pipe 12, the insulated water inlet pipe 13, the heating valve 14 and the insulated valve 15, the outlet side connection state of the heat pump unit 3 can be flexibly switched. The water passing through the heat pump unit 3 can be sent to the heating water tank 1 or the insulated water tank 2 according to usage requirements. The two water tanks can be heated by the same heat pump unit 3. The first pump group 6 and the liquid supply pipe 11 of the heat pump unit 3 can also be used to replenish the water in the heating water tank 1 into the insulated water tank 2, so that the pipeline structure of the entire hot water system is simple, with fewer components, and the production cost is greatly reduced.

[0063] In some feasible embodiments of the present invention, a return pipe 16 is provided on the water outlet side of the insulated water tank 2, the outlet of the return pipe 16 is connected to the inlet of the insulated water inlet pipe 13, and the liquid supply pipe 11 and the return pipe 16 are respectively installed with a check valve that only allows liquid to flow to the insulated water inlet pipe 13.

[0064] The design is equivalent to sharing the heat preservation water inlet pipe 13 by the water return pipe 16 and the liquid supply pipe 11, and the check valves installed on the liquid supply pipe 11 and the water return pipe 16 ensure the unidirectionality of water flow, that is, only allowing the liquid to flow to the heat preservation water inlet pipe 13, and the water supply and return pipeline of the heat preservation water tank 2 is more concise. When the heat preservation valve 15 of the heat preservation water inlet pipe 13 is closed, neither the water outlet side of the heat pump unit 3 nor the water return pipe 16 can send water into the heat preservation water tank 2; when the heat preservation valve 15 of the heat preservation water inlet pipe 13 is opened, water is sent into the heat preservation water tank 2 by the power provided by the first pump set 6 and the second pump set 7.

[0065] It should be pointed out that, as a preferred solution, each pump set contains two water pumps arranged in parallel, usually only one water pump is started, when one of the water pumps fails or needs maintenance, the other water pump can be started to continue working, ensuring uninterrupted water supply of the system, this design can significantly improve the reliability and stability of the system.

[0066] In addition, in order to realize the automatic control of the double-tank hot water system, the first temperature sensor 17 for detecting the actual water temperature t1 and the first liquid level sensor 18 for detecting the actual liquid level w2 are arranged in the heating water tank 1, and the second temperature sensor 19 for detecting the actual water temperature t2 and the second liquid level sensor 20 for detecting the actual liquid level w1 are arranged in the heat preservation water tank 2. The pressure sensor 21 for detecting the pipe network pressure p1 is arranged on the outlet side of the heat preservation water tank 2, and the third temperature sensor 22 for detecting the return water temperature t3 is arranged on the water return pipe 16. The controller receives the detection data of the temperature sensor and the liquid level sensor, and controls the running state of the hot water system.

[0067] As shown in Figure 2 , the application also provides a control method of the double-tank hot water system, which is applied to the double-tank hot water system and includes the following steps.

[0068] detecting the actual water temperature t2 and the actual liquid level w1 of the heat preservation water tank;

[0069] judging whether the actual water temperature t2 of the heat preservation water tank is less than a set heat preservation lower limit temperature t 2,0 or the actual liquid level w1 of the heat preservation water tank is less than a set heat preservation lower limit liquid level w 1,0 ;

[0070] If yes, it indicates that the water temperature or the liquid level of the heat preservation water tank is insufficient, which cannot guarantee the hot water supply of the user end, at this time, the hot water supplement action is performed, the pressure difference water supply pipe is connected (the switch valve is opened), the water outlet side of the heat pump unit is connected to the heat preservation water tank (the heat preservation valve is opened and the heating valve is closed), the first pump set is started, and the heat pump unit is started or stopped according to the working parameters of the heating water tank, when the heat pump unit is stopped, the water flowing out of the heating water tank is sent to the heat preservation water tank through the water outlet side of the heat pump unit, and when the heat pump unit is started, the water flowing through the water outlet side of the heat pump unit is heated.

[0071] The design can quickly and efficiently supplement hot water in the heat preservation water tank by performing a hot water supplement action when the water temperature or water level of the heat preservation water tank is insufficient, supplementing water in the heating water tank into the heat preservation water tank by using the pressure difference water supplement pipe and the first pump set, and controlling the opening or closing of the heat pump unit according to the working parameters of the heating water tank.

[0072] On this basis, in some feasible embodiments of the present application, the controlling of the opening or closing of the heat pump unit according to the working parameters of the heating water tank comprises:

[0073] detecting the actual water level w2 and the actual water temperature t1 of the heating water tank;

[0074] judging whether the actual water level w2 of the heating water tank is greater than or equal to the set heating upper limit water level w 2,1 and the actual water temperature t1 of the heating water tank is greater than or equal to the set heating upper limit temperature t 1,2 .

[0075] if yes, it indicates that the water temperature and water level in the heating water tank are both sufficient, and the hot water supplement demand of the heat preservation water tank can be met, so the heat pump unit is closed;

[0076] if no, it indicates that the water temperature or water level in the heating water tank is insufficient, and the hot water supplement demand of the heat preservation water tank cannot be met, so the heat pump unit is opened, and the water sent to the heat preservation water tank is heated by the heat pump unit.

[0077] The advantage of this design is that by monitoring the actual water level w2 and the actual water temperature t1 of the heating water tank in real time, the system can intelligently determine when to close or open the heat pump unit. When the heating water tank can meet the hot water supplement demand, the heat pump unit is closed to reduce unnecessary energy consumption. When the heating water tank cannot meet the hot water supplement demand, the heat pump unit is opened to ensure that the hot water in the heat preservation water tank is effectively supplemented, achieving the effect of energy saving and high efficiency.

[0078] As a preferred solution, the controlling of the opening or closing of the heat pump unit according to the working parameters of the heating water tank further comprises: after the heat pump unit is closed, judging whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit temperature t 2,1 and the actual water level w1 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit water level w 1,1 , if no, the hot water supplement action is continuously performed.

[0079] The advantage of this design is that when the water temperature and water level of the heating water tank are sufficient, the hot water supplement demand of the heat preservation water tank can be met, so it is directly judged whether the hot water of the heat preservation water tank is supplemented in place, without the need to analyze the state of the heating water tank in between, simplifying the control logic.

[0080] As a preferred solution, the controlling of the opening or closing of the heat pump unit according to the working parameters of the heating water tank further comprises:

[0081] After the heat pump unit is started, the actual liquid level w2 and the actual water temperature t1 of the heating water tank are detected;

[0082] It is judged whether the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 or the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 .

[0083] If yes, it indicates that the water temperature or the water level of the heating water tank is too low, the hot water supplement action is stopped, the heating action and / or the water supplement action are selected to be performed on the heating water tank, and the heating water tank is heated and / or watered in time;

[0084] If no, it indicates that the water temperature and the water temperature of the heating water tank are normal, at this time, it can be judged whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit temperature t 2,1 and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set heat preservation upper limit liquid level w 1,1 If no, the amount of hot water of the heat preservation water tank is still insufficient, and the hot water supplement action is continuously performed.

[0085] This design monitors the actual liquid level w2 and the actual water temperature t1 of the heating water tank in the process of supplementing hot water to the heat preservation water tank when the water level and the water level of the heating water tank do not reach the upper limit state, performs the heating action and / or the water supplement action when the water temperature or the water level is insufficient, the condensing side of the heat pump unit heats the low-temperature water flowing out of the heating water tank, increases the heat exchange temperature difference of the condensing side, achieves efficient heat production management, supplements hot water to the heat preservation water tank after the water temperature and the water level of the heating water tank are in place, improves the water temperature stability of the heat preservation water tank, and improves the energy efficiency of the hot water system.

[0086] As shown in FIGS. Figure 3 , 4 On this basis, in some feasible embodiments of the present application, selecting to perform the heating action and / or the water supplement action on the heating water tank includes:

[0087] When the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 , the water supplement action is performed, the differential pressure water supplement pipe is turned off (the switch valve is closed), and the external water supplement pipe is connected to the heating water tank (the water supplement valve is opened) to supplement water to the heating water tank;

[0088] When the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 , the heating action is performed, the differential pressure water supplement pipe is turned off (the switch valve is closed), and the first pump group and the heat pump unit are started to connect the water outlet side of the heat pump unit to the heating water tank.

[0089] The function of this design is to start the heat pump unit and the external water supplement pipe to heat and supplement water to the heating tank when the water temperature or water level in the heating tank is insufficient, so that the heating tank has sufficient hot water to supply to the heat preservation tank.

[0090] It should be noted that, as a preferred solution, selecting to perform the heating action and / or the water supplement action on the heating tank further comprises:

[0091] First, determine whether the actual liquid level w2 of the heating tank is less than the set heating lower limit liquid level w 2,0 ;

[0092] If yes, it means that the water level of the heating tank is too low, and the water supplement action is performed, the pressure differential water supplement pipe is turned off (the switch valve is closed), the external water supplement pipe is turned on to supplement water to the heating tank (the water supplement valve is opened), and the actual liquid level w2 of the heating tank is greater than or equal to the set heating upper limit liquid level w 2,1 Then, determine whether the actual water temperature t1 of the heating tank is less than the set heating lower limit temperature t 1,0 If yes, it means that the water temperature of the heating tank is too low, and the heating action is performed, the pressure differential water supplement pipe is turned off (the switch valve is closed), the first pump group and the heat pump unit are turned on, and the water outlet side of the heat pump unit is connected to the heating tank (the heating valve is opened and the heat preservation valve is closed), and the actual water temperature t1 of the heating tank is greater than or equal to the set heating upper limit temperature t 1,2 At this time, the water temperature and the water level of the heating tank are sufficient, and the actual water temperature t2 and the actual liquid level w1 of the heat preservation tank are re-detected.

[0093] If no, it means that the amount of water remaining in the heating tank can meet the hot water supplement demand of the heat preservation tank, and it is determined whether the actual water temperature t1 of the heating tank is less than the set heating lower limit temperature t 1,0 If no, it means that the amount of water and the water temperature in the heating tank can meet the hot water supplement demand of the heat preservation tank, and the actual water temperature t2 and the actual liquid level w1 of the heat preservation tank are re-detected. If yes, it means that the water temperature of the heating tank is too low, and the heating action is performed, the pressure differential water supplement pipe is turned off (the switch valve is closed), the first pump group and the heat pump unit are turned on, and the water outlet side of the heat pump unit is connected to the heating tank (the heating valve is opened and the heat preservation valve is closed), and the actual water temperature t1 of the heating tank is greater than or equal to the set heating upper limit temperature t 1,2 At this time, the amount of water and the water temperature of the heating tank can meet the hot water supplement demand of the heat preservation tank, and the actual water temperature t2 and the actual liquid level w1 of the heat preservation tank are re-detected.

[0094] This design can make the water level and water temperature in the heating tank recover to a state capable of supplementing hot water to the heat preservation tank as soon as possible. When the water level and the water temperature of the heating tank are appropriate, the actual liquid level w2 is greater than or equal to the set heating lower limit liquid level w 2,0 , and the actual water temperature t1 is greater than or equal to the set heating lower limit temperature t 1,0The actual water temperature t2 and the actual liquid level w1 of the heat preservation water tank can be returned to, the waiting time of the heat preservation water tank is shortened, and the hot water use demand of the user end is ensured to be met.

[0095] As shown in Figure 5 , as a preferred solution, the control method further comprises:

[0096] determining whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to a set upper limit temperature t 2,1 and the actual liquid level w1 of the heat preservation water tank is greater than or equal to a set upper limit liquid level w 1,1 If yes, it indicates that the amount of hot water in the heat preservation water tank is sufficient, and the opening or closing of the second pump group is controlled according to the outlet side working parameter of the heat preservation water tank.

[0097] Since the outlet side of the heat preservation water tank is connected to the user end, after the amount of hot water in the heat preservation water tank is sufficient, the water storage condition of the outlet side pipe network can be found in time by monitoring the outlet side working parameter of the heat preservation water tank, and then the water between the heat preservation water tank and the pipe network is driven to circulate by opening the second pump group, so that hot water is supplemented into the outlet side pipe network of the heat preservation water tank, and the use experience of the user is improved.

[0098] On this basis, in some feasible embodiments of the present application, the opening or closing of the second pump group according to the outlet side working parameter of the heat preservation water tank comprises:

[0099] detecting the outlet side pipe network pressure p1 of the heat preservation water tank;

[0100] determining whether the outlet side pipe network pressure p1 of the heat preservation water tank is less than a set lower limit pressure p0;

[0101] If yes, it indicates that the water pressure of the outlet side of the heat preservation water tank is small, the amount of water is insufficient, and hot water cannot be immediately discharged when the user end has a hot water use demand, so the second pump group is opened to send water back to the heat preservation water tank (the heat preservation valve is opened), until the outlet side pipe network pressure p1 of the heat preservation water tank is greater than or equal to a set upper limit pressure p2, at this time, the outlet side return water temperature t3 of the heat preservation water tank is detected, and when the outlet side return water temperature t3 of the heat preservation water tank is greater than or equal to a set return water temperature t 3,0 , it indicates that the water pressure in the outlet side pipe network of the heat preservation water tank is sufficient and the water temperature is moderate, so the second pump group is closed to stop sending water back to the heat preservation water tank (the heat preservation valve is closed), and the outlet side pipe network pressure p1 of the heat preservation water tank is returned to be detected again;

[0102] If no, it indicates that the water pressure of the outlet side of the heat preservation water tank is moderate, the amount of water is appropriate, and hot water can be immediately discharged when the user end has a hot water use demand, at this time, the outlet side return water temperature t3 of the heat preservation water tank is detected, and when the outlet side return water temperature t3 of the heat preservation water tank is greater than or equal to a set return water temperature t 3,0When the outlet-side pipe network pressure p1 of the heat preservation water tank is greater than the set outlet-side pipe network pressure p

[0103] This design stores sufficient hot water in the outlet-side pipe network by detecting the outlet-side pipe network pressure p1 and the outlet-side return water temperature t3, and guarantees the user experience. At the same time, when the outlet-side water pressure is insufficient, the water quantity in the return pipe is small, and the outlet-side return water temperature t3 cannot reflect the real water temperature in the pipe network. The control accuracy can be improved by detecting the outlet-side return water temperature t3 after the outlet-side water pressure is increased.

[0104] As shown in Figure 5 , as a preferred method, the control method further comprises:

[0105] After detecting the outlet-side return water temperature t3 of the heat preservation water tank, when the outlet-side return water temperature t3 of the heat preservation water tank is less than the set return water temperature t 3,0 , it is indicated that the water temperature of the outlet-side pipe network is still low. It is determined whether the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set lower limit temperature t 2,0 of the heat preservation and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set lower limit liquid level w 1,0 of the heat preservation.

[0106] If yes, it is indicated that the water quantity and the water temperature in the heat preservation water tank can meet the return water temperature increasing requirement. The second pump set is closed, the water is stopped from being sent back to the heat preservation water tank (the heat preservation valve is closed), and the outlet-side pipe network pressure p1 of the heat preservation water tank is re-detected.

[0107] If no, it is indicated that the water quantity and the water temperature in the heat preservation water tank cannot meet the return water temperature increasing requirement. A hot water supplement action is performed until the actual water temperature t2 of the heat preservation water tank is greater than or equal to the set upper limit temperature t 2,1 of the heat preservation and the actual liquid level w1 of the heat preservation water tank is greater than or equal to the set upper limit liquid level w 1,1 of the heat preservation. The second pump set is closed, the water is stopped from being sent back to the heat preservation water tank (the heat preservation valve is closed), and the outlet-side pipe network pressure p1 of the heat preservation water tank is re-detected.

[0108] The advantage of this design is that the cause of the low temperature of the outlet-side pipe network can be accurately identified. The outlet-side pipe network water quantity and water temperature can be effectively increased by re-detecting the outlet-side working parameters of the heat preservation water tank or supplementing hot water to the heat preservation water tank.

[0109] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and the like are specifically intended to be open-ended. These terms mean that a process, method, article, device or apparatus that "comprises", "comprising", "includes" or "including" something is not necessarily limited to the stated features, but can include other features that are not expressly listed or inherent to such process, method, article, device or apparatus. The words "preferably", "preferred", "prefer" or other similar words have no influence on the scope of the invention.

[0110] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, the techniques, methods, and apparatus should be considered part of the disclosure as appropriate. In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not limiting. Thus, other examples of the exemplary embodiments can have different values. It should be noted that like numbers and letters refer to like items throughout the following figures, and thus once an item is defined in one figure, it is not necessary to discuss it further in subsequent figures.

[0111] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the following claims.

Claims

1. A control method for a dual-tank hot water system, the dual-tank hot water system comprising: An insulated water tank, a heating water tank, and a heat pump unit, wherein the water outlet side of the insulated water tank is connected to the user end via a second pump unit, a pressure differential water supply pipe with controllable on / off state is connected between the heating water tank and the insulated water tank, and the heating water tank is also connected to an external water supply pipe; the water inlet side of the heat pump unit is connected to the water outlet side of the heating water tank via a first pump unit, and the water outlet side of the heat pump unit can be switchably connected to the water inlet side of the heating water tank and / or the water inlet side of the insulated water tank; Characterized in that the control method includes: Detecting the actual water temperature t2 and the actual liquid level w1 of the thermal insulation water tank; Determine whether the actual water temperature t2 of the thermal insulation water tank is less than the set thermal insulation lower limit temperature t 2,0 Or the actual liquid level w1 of the thermal insulation water tank is less than the set thermal insulation lower limit liquid level w 1,0 ; If so, perform the hot water replenishment action, connect the pressure difference water replenishment pipe, connect the water outlet side of the heat pump unit to the insulated water tank, start the first pump unit, detect the actual liquid level w2 and actual water temperature t1 of the heating water tank, and determine whether the actual liquid level w2 of the heating water tank ≥ the set upper limit liquid level w1. 2,1 The actual water temperature t1 of the heating water tank is greater than or equal to the set upper limit temperature t 1,2 If yes, then turn off the heat pump unit; if no, then turn on the heat pump unit.

2. The control method according to claim 1, characterized in that: The heating water tank is provided with a heating water inlet pipe, the insulation water tank is provided with an insulation water inlet pipe, the water outlet side of the heat pump unit is provided with a liquid supply pipe, and the heating water inlet pipe and the insulation water inlet pipe are both connected to the liquid supply pipe; The heating water inlet pipe is installed with a heating valve, and the insulation water inlet pipe is installed with an insulation valve, and the outlet side connection state of the heat pump unit is switched by the heating valve and the insulation valve.

3. The control method according to claim 2, characterized in that: A return pipe is provided on the water outlet side of the insulated water tank, the outlet of the return pipe is connected to the inlet of the insulated water inlet pipe, and the liquid supply pipe and the return pipe are respectively equipped with a check valve that only allows liquid to flow to the insulated water inlet pipe.

4. The control method according to any one of claims 1 to 3, characterized in that: Each pump unit consists of two water pumps connected in parallel.

5. The control method according to claim 1, characterized in that: Controlling the heat pump unit to be turned on or off according to the operating parameters of the heating water tank further includes: After shutting down the heat pump unit, it is determined whether the actual water temperature t2 of the insulation water tank is greater than or equal to the set insulation upper limit temperature t 2,1 And the actual liquid level w1 of the thermal insulation water tank is greater than or equal to the set upper limit of thermal insulation level w 1,1 If not, continue to perform the hot water replenishment action.

6. The control method according to claim 1, characterized in that: Controlling the heat pump unit to be turned on or off according to the operating parameters of the heating water tank further includes: After starting the heat pump unit, detecting the actual liquid level w2 and actual water temperature t1 of the heating water tank; Determine whether the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 Or the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 ; If yes, stop performing the hot water replenishment action, and select to perform the heating action and / or water replenishment action on the heating water tank; If not, it is determined whether the actual water temperature t2 of the thermal insulation water tank is greater than or equal to the set upper temperature limit t 2,1 And the actual liquid level w1 of the thermal insulation water tank is greater than or equal to the set upper limit of thermal insulation level w 1,1 If not, continue to perform the hot water replenishment action.

7. The control method according to claim 5 or 6, characterized in that: The control method further includes: Determine whether the actual water temperature t2 of the insulation water tank is greater than or equal to the set insulation upper limit temperature t 2,1 And the actual liquid level w1 of the thermal insulation water tank is greater than or equal to the set upper limit of thermal insulation level w 1,1 If so, the second pump group is controlled to be turned on or off according to the working parameters on the outlet side of the insulated water tank.

8. The control method according to claim 7, characterized in that: Controlling the opening or closing of the second pump group according to the outlet side working parameters of the thermal insulation water tank includes: Detecting the outlet pipe network pressure p1 of the thermal insulation water tank; Determine whether the outlet side pipe network pressure p1 of the thermal insulation water tank is less than the set lower limit pressure p0; If yes, start the second pump group to send water back to the insulated water tank until the outlet pipe network pressure p1 ≥ the set upper limit pressure p2, and detect the outlet return water temperature t3 of the insulated water tank; If not, then detect the return water temperature t3 at the outlet side of the thermal insulation water tank; Among them, after detecting the return water temperature t3 at the outlet of the insulation water tank, when the return water temperature t3 at the outlet of the insulation water tank ≥ the set return water temperature t 3,0 When the pressure reaches 0.01, turn off the second pump group, stop sending water back to the insulated water tank, and return to re-test the outlet side pipe network pressure p1 of the insulated water tank.

9. The control method according to claim 8, characterized in that: The control method further includes: After detecting the return water temperature t3 at the outlet of the insulation water tank, when the return water temperature t3 at the outlet of the insulation water tank is less than the set return water temperature t 3,0 When the actual water temperature t2 of the thermal insulation water tank is greater than the set thermal insulation lower limit temperature t 2,0 And the actual liquid level w1 of the thermal insulation water tank is greater than or equal to the set lower limit liquid level w 1,0 ; If yes, then shut down the second pump group, stop sending water back to the insulated water tank, and return to re-test the outlet side pipe network pressure p1 of the insulated water tank; If not, the hot water replenishment action is performed until the actual water temperature t2 of the insulation water tank ≥ the set insulation upper limit temperature t 2,1 And the actual liquid level w1 of the thermal insulation water tank is greater than or equal to the set upper limit of thermal insulation level w 1,1 , turn off the second pump group, stop sending water back to the insulated water tank, and return to re-test the outlet side pipe network pressure p1 of the insulated water tank.

10. The control method according to claim 6, characterized in that: Selecting to perform a heating action and / or a water replenishing action on the heating water tank includes: When the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 When the water supply is 100 ℃, the water supply action is performed, the pressure difference water supply pipe is closed, and the external water supply pipe is connected to supply water to the heating water tank; When the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 When the heating action is performed, the pressure difference water supply pipe is closed, the first pump group and the heat pump group are turned on, and the water outlet side of the heat pump group is connected to the heating water tank.

11. The control method according to claim 10, characterized in that: Selecting to perform a heating action and / or a water replenishing action on the heating water tank also includes: First determine whether the actual liquid level w2 of the heating water tank is less than the set heating lower limit liquid level w 2,0 ; If yes, the water replenishment action is performed until the actual liquid level w2 of the heating water tank is greater than or equal to the set upper limit liquid level w 2,1 , determine whether the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 If so, the heating action is performed until the actual water temperature t1 of the heating water tank is greater than the set upper limit temperature t 1,2 , return to re-detect the actual water temperature t2 and actual liquid level w1 of the thermal insulation water tank; If not, it is determined whether the actual water temperature t1 of the heating water tank is less than the set heating lower limit temperature t 1,0 If not, return to re-detect the actual water temperature t2 and actual liquid level w1 of the insulation water tank. If yes, perform the heating action until the actual water temperature t1 of the heating water tank ≥ the set upper limit temperature t 1,2 , return to re-detect the actual water temperature t2 and actual liquid level w1 of the insulated water tank.

Images