Double-water-tank hot water system and control method thereof

Abstract

The invention 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 side through a second pump unit, and a pressure difference water supplementing pipe with the controllable on-off state is connected between the heating water tank and the heat preservation water tank; the heating water tank is further connected with an external water supplementing pipe. The water inlet side of the heat pump unit is connected to the water outlet side of the heating water tank through the first pump set, and the water outlet side of the heat pump unit is connected with the water inlet side of the heating water tank and / or the water inlet side of the heat preservation water tank in a switchable mode. The heat pump unit is designed on the water outlet side of the heating water tank, the heating water tank and the heat preservation water tank are heated or supplemented with water by switching the connecting state of the water outlet side of the heat pump unit, the condensation temperature of the heat pump unit is reduced while the system structure is simplified, and the operation energy efficiency of the hot water system is effectively improved.

Description

Technical Field

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

[0002] Centralized hot water systems are widely used in schools, office buildings, and aquaculture. Traditional centralized hot water uses fossil fuel combustion or electric heating to produce hot water, which is energy-intensive and polluting. As the goal of energy conservation and carbon reduction has gained consensus, more new heat sources are being used in the field of hot water, including solar energy, soil energy, and air energy, which are both energy-saving and environmentally friendly. Solar energy has regional differences and instability, and soil energy has harsh conditions for use, so its widespread use is limited. Air source heat pumps, as a new type of heat source that can produce heat stably and has an energy efficiency 2 to 3 times higher than traditional heat sources, are widely promoted and used.

[0003] There are design solutions in the prior art that can improve the energy efficiency of air source hot water systems. For example, the patent application with publication number CN112665183A discloses an air source heat pump dual-tank hot water system and its control method. According to the water demand of the system at different times of the year, the system energy efficiency is improved by adjusting the number of heat pump units put into use. However, the hot water system needs to be equipped with multiple air source heat pump units, which has complex pipe connections and high costs. In addition, when multiple units work at the same time, the energy consumption of the whole machine is high, and the system energy efficiency still needs to be improved.

[0004] Therefore, how to design a dual-tank hot water system with simple pipe connections and higher energy efficiency and its control method is a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0005] In order to solve the problems of complex connection and low energy efficiency of existing hot water systems, the present invention proposes a dual-water tank hot water system and a control method thereof. The hot water system designs a heat pump unit on the water outlet side of the heating water tank, and switches the connection state of the water outlet side of the heat pump unit to achieve heating or water replenishment to the heating water tank and the insulation water tank, thereby simplifying the system structure and reducing the condensing temperature of the heat pump unit, thereby effectively improving the operating energy efficiency of the hot water system.

[0006] The technical solution adopted by the present invention is to design a double-tank hot water system, including: an insulated water tank, a heating water tank and a heat pump unit, the water outlet side of the insulated water tank is connected to the user end through the second pump unit, a pressure difference 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 through the first pump unit, and the water outlet side of the heat pump unit can be switched to connect to the water inlet side of the heating water tank and / or the water inlet side of the insulated water tank.

[0007] Furthermore, 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 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. Among them, 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.

[0008] Furthermore, 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 installed with check valves that only allow liquid to flow to the insulated water inlet pipe.

[0009] Furthermore, each pump group includes two water pumps arranged in parallel.

[0010] The present invention also proposes a control method for a dual-tank hot water system, which is applied to the dual-tank hot water system, and includes:

[0011] Detect the actual water temperature of the insulation water tank 2 and the actual liquid level w 1 ;

[0012] Determine whether the actual water temperature of the insulation water tank is t 2 <Set the lower limit temperature of insulation 2,0 Or the actual liquid level of the insulation water tank w 1 <Set the lower limit of insulation level w 1,0 ;

[0013] 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 group, and control the heat pump unit to turn on or off according to the working parameters of the heating water tank.

[0014] Further, controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank includes:

[0015] Detect the actual liquid level of the heating water tank w 2 and the actual water temperature t 1 ;

[0016] Determine whether to heat the actual liquid level of the water tank 2 ≥Set the upper limit of heating level w 2,1 And the actual water temperature of the heating water tank is t 1 ≥Set the upper limit temperature of heating 1,2 ;

[0017] If yes, shut down the heat pump unit;

[0018] If not, turn on the heat pump unit.

[0019] Further, controlling the heat pump unit to be turned on or off according to the working parameters of the heating water tank also includes: after turning off the heat pump unit, determining whether the actual water temperature t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 , if not, continue to perform the hot water replenishment action.

[0020] Furthermore, controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank also includes:

[0021] After starting the heat pump unit, check the actual liquid level of the heating water tank. 2 and the actual water temperature t 1 ;

[0022] Determine whether to heat the actual liquid level of the water tank 2 <Set the lower limit of heating level w 2,0 Or the actual water temperature of the heating tank t 1 <Set the lower limit temperature of heating 1,0 ;

[0023] 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;

[0024] If not, determine whether the actual water temperature of the insulation water tank is t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 , if not, continue to perform the hot water replenishment action.

[0025] Furthermore, the control method also includes:

[0026] Determine whether the actual water temperature of the insulation water tank is t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of 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 insulation water tank.

[0027] Further, controlling the opening or closing of the second pump group according to the working parameters at the outlet side of the thermal insulation water tank includes:

[0028] Detect the outlet pipe network pressure p of the insulation water tank 1 ;

[0029] Determine whether the outlet pipe pressure of the insulated water tank is 1 <Set lower limit pressure p0 ;

[0030] If yes, start the second pump group to send water back to the insulation water tank until the outlet pipe pressure of the insulation water tank reaches p 1 ≥Set upper limit pressure p 2 , detect the return water temperature t at the outlet of the insulation water tank 3 ;

[0031] If not, then detect the return water temperature t at the outlet of the insulation water tank. 3 ;

[0032] Among them, the return water temperature t at the outlet of the insulation water tank is detected 3 Afterwards, when the return water temperature at the outlet of the insulation water tank is 3 ≥Set return water temperature t 3,0 When the water is pumped back to the insulated water tank, turn off the second pump group, stop sending water back to the insulated water tank, and return to re-test the outlet pipe network pressure p of the insulated water tank. 1 .

[0033] Furthermore, the control method also includes:

[0034] Detect the return water temperature t at the outlet of the insulation water tank 3 Afterwards, when the return water temperature at the outlet of the insulation water tank is 3 <Set return water temperature t 3,0 When the actual water temperature of the insulation water tank is t 2 ≥Set the lower limit temperature of insulation 2,0 And the actual liquid level of the insulation water tank w 1 ≥Set the lower limit of insulation level w 1,0 ;

[0035] If yes, turn off the second pump group, stop sending water back to the insulation water tank, and return to re-test the outlet pipe network pressure p of the insulation water tank. 1 ;

[0036] If not, hot water replenishment is performed until the actual water temperature of the insulation water tank reaches t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 , turn off the second pump group, stop sending water back to the insulation water tank, return to re-test the outlet side pipe network pressure p of the insulation water tank 1 .

[0037] Further, selecting to perform a heating action and / or a water replenishing action on the heating water tank includes:

[0038] When the actual liquid level of the heating water tank is w 2 <Set the lower limit of heating level w 2,0When the water supply is on, the water supply action is executed, the pressure difference water supply pipe is closed, and the external water supply pipe is connected to supply water to the heating water tank;

[0039] When the actual water temperature of the heating water tank is t 1 <Set the lower limit temperature of heating 1,0 When the heating action is performed, the pressure difference water supply pipe is closed, the first pump unit and the heat pump unit are turned on, and the water outlet side of the heat pump unit is connected to the heating water tank.

[0040] Further, selecting to perform a heating action and / or a water replenishing action on the heating water tank also includes:

[0041] First determine whether to heat the actual liquid level of the water tank w 2 <Set the lower limit of heating level w 2,0 ;

[0042] If yes, the water replenishment action is performed until the actual liquid level of the heating water tank reaches w 2 ≥Set the upper limit of heating level w 2,1 , determine whether to heat the actual water temperature of the water tank t 1 <Set the lower limit temperature of heating 1,0 If yes, the heating action is performed until the actual water temperature of the heating water tank reaches t 1 ≥Set the upper limit temperature of heating 1,2 , return to re-test the actual water temperature t of the insulation water tank 2 and the actual liquid level w 1 ;

[0043] If not, determine whether to heat the actual water temperature of the water tank t 1 <Set the lower limit temperature of heating 1,0 Otherwise, return to re-check the actual water temperature t of the insulation water tank 2 and the actual liquid level w 1 If yes, the heating action is performed until the actual water temperature of the heating water tank reaches t 1 ≥Set the upper limit temperature of heating 1,2 , return to re-test the actual water temperature t of the insulation water tank 2 and the actual liquid level w 1 .

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

[0045] 1. The heat pump unit is designed at the outlet side of the heating water tank. By switching the outlet connection state of the heat pump unit, heating of the heating water tank and the insulation water tank is realized. When the heat pump unit is turned on, the outlet water of the heating water tank is heated to reduce the condensation temperature of the heat pump unit, effectively improving the operation energy efficiency of the hot water system. Moreover, the power is provided by the first pump unit, which can not only completely heat the heating cycle of the heating water tank, but also complete the heating and water replenishment cycle of the insulation water tank, simplifying the system structure and reducing the production cost of the hot water system.

[0046] 2. Monitor the actual water temperature of the insulation water tank 2 and the actual liquid level w 1 , when the water temperature or water level is insufficient, hot water replenishment is performed, the water in the heating water tank is replenished into the insulation water tank through the pressure difference water replenishment pipe and the first pump group, and the heat pump unit is controlled to be turned on or off according to the working parameters of the heating water tank, so that the insulation water tank can be quickly and efficiently filled with hot water;

[0047] 3. Monitor the actual liquid level of the heating water tank during the process of adding hot water to the insulation water tank. 2 and the actual water temperature t 1 , when the water temperature or water level is insufficient, the heating action and / or water replenishment action is performed. The condensing side of the heat pump unit heats the low-temperature water flowing out of the heating water tank, increasing the heat exchange temperature difference on the condensing side to achieve efficient heat production management. After the water temperature and water level of the heating water tank are in place, hot water is added to the insulation water tank to improve the water temperature stability of the insulation water tank and improve the energy efficiency of the hot water system;

[0048] 4. After the hot water in the insulation water tank is sufficient, monitor the working parameters of the outlet side of the insulation water tank. 3 When the temperature drops too low, the water in the pipe network is pumped into the insulation water tank and then sent out again until the return water temperature at the outlet reaches t 3 The water temperature rises, ensuring that each user end has instant hot water when in use, improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

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

[0051] Figure 2 It is a schematic diagram of the operation logic of the thermal insulation water tank of the present invention;

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

[0053] Figure 4 It is a logical diagram of water replenishment of the heating water tank of the present invention;

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

[0055] Description of the drawings: 1. Heating water tank; 2. Insulated water tank; 3. Heat pump unit; 4. User end; 5. External water supply pipe; 6. First pump group; 7. Second pump group; 8. Pressure difference water supply pipe; 9. Switch valve; 10. Water supply valve; 11. Liquid supply pipe; 12. Heating water inlet pipe; 13. Insulated water inlet pipe; 14. Heating valve; 15. Insulated valve; 16. Return 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, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0057] like Figure 1 As shown, the dual-tank hot water system proposed in the present invention includes: a heating water tank 1, an insulation 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 unit 6, and the water outlet side of the heat pump unit 3 can be switched to connect to the water inlet side of the heating water tank 1 and / or the water inlet side of the insulation water tank 2. When the first pump unit 6 is turned on, the water flowing out of the heating water tank 1 enters 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 insulation water tank 2. The water outlet side of the insulation water tank 2 is connected to the user end 4 through the second pump unit 7, and the water sent out of the insulation 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 insulation water tank 2. The pressure differential water supply pipe 8 is equipped with a switch valve 9 to control its on and off state. The pressure differential water supply pipe 8 is usually located at the lower part of the heating water tank 1 and the insulation water tank 2. When the pressure differential water supply pipe 8 is connected, the heating water tank 1 and the insulation water tank 2 are connected, and the liquid levels of the two water tanks tend to be the same under the pressure difference. The heating water tank 1 is also connected to an external water supply pipe 5. The external water supply pipe 5 is equipped with a water supply valve 10 to control its on and off state. The water source of the 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 insulation 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 to reduce the condensation temperature of the heat pump unit 3, effectively improving the operating energy efficiency of the hot water system, and providing power through the first pump unit 6, which can not only completely heat the heating cycle of the heating water tank 1, but also complete the heating and water replenishment cycle of the insulation 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 insulation water tank 2 is provided with an insulation 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 insulation 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 insulation water inlet pipe 13 is installed with an insulation valve 15, and the connection state of the water outlet side of the heat pump unit 3 is switched by the heating valve 14 and the insulation valve 15. When the heating valve 14 is opened and the insulation 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 insulation valve 15 is opened, the water outlet side of the heat pump unit 3 is connected to the water inlet side of the insulation 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 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 unit 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 check valves that only allow liquid to flow to the insulated water inlet pipe 13.

[0064] This design is equivalent to the return pipe 16 and the liquid supply pipe 11 sharing the insulated water inlet pipe 13. The check valves installed on the liquid supply pipe 11 and the return pipe 16 ensure the unidirectionality of the water flow, that is, the liquid is only allowed to flow to the insulated water inlet pipe 13, and the water supply and return pipes of the insulated water tank 2 are simpler. When the insulated valve 15 of the insulated water inlet pipe 13 is closed, the water outlet side of the heat pump unit 3 and the return pipe 16 cannot send water into the insulated water tank 2; when the insulated valve 15 of the insulated water inlet pipe 13 is opened, the first pump group 6 and the second pump group 7 provide power to send water into the insulated water tank 2.

[0065] It should be pointed out that, as a preferred solution, each pump group includes two water pumps arranged in parallel, and usually only one water pump is turned on. When one of the water pumps fails or needs maintenance, the other water pump can be turned on to continue working to ensure uninterrupted water supply to 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 dual-tank hot water system, the heating water tank 1 is provided with a device for detecting the actual water temperature t 1 The first temperature sensor 17 and the first temperature sensor 17 for detecting the actual liquid level w 2 The first liquid level sensor 18 is provided in the thermal insulation water tank 2 for detecting the actual water temperature t 2 The second temperature sensor 19 and the second temperature sensor 19 for detecting the actual liquid level w 1 The outlet side of the insulated water tank 2 is equipped with a second liquid level sensor 20 for detecting the pipe network pressure p 1 The return pipe 16 is provided with a pressure sensor 21 for detecting the return water temperature t 3 The controller receives the detection data of the temperature sensor and the liquid level sensor and controls the operation state of the hot water system.

[0067] like Figure 2 As shown, the present invention also proposes a control method for a double water tank hot water system, which is applied to the above double water tank hot water system, including:

[0068] Detect the actual water temperature of the insulation water tank 2 and the actual liquid level w 1 ;

[0069] Determine whether the actual water temperature of the insulation water tank is t 2 <Set the lower limit temperature of insulation 2,0 Or the actual liquid level of the insulation water tank w 1 <Set the lower limit of insulation level w 1,0 ;

[0070] If so, it means that the current water temperature or water level in the insulated water tank is insufficient, and the hot water supply at the user end cannot be guaranteed. At this time, the hot water replenishment action is performed, the pressure difference water replenishment pipe is connected (the switch valve is opened), and the water outlet side of the heat pump unit is connected to the insulated water tank (the insulation valve is opened and the heating valve is closed). The first pump group is turned on, and the heat pump unit is controlled to be turned on or off according to the working parameters of the heating water tank. When the heat pump unit is turned off, the water flowing out of the heating water tank is sent to the insulated water tank through the water outlet side of the heat pump unit. When the heat pump unit is turned on, the water flowing through its water outlet side is heated.

[0071] This design performs hot water replenishment when the water temperature or water level in the insulated water tank is insufficient, uses the pressure difference water replenishment pipe and the first pump group to replenish the water in the heating water tank into the insulated water tank, and controls the opening or closing of the heat pump unit according to the working parameters of the heating water tank. The insulated water tank can be filled with hot water quickly and efficiently.

[0072] On this basis, in some feasible embodiments of the present invention, controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank includes:

[0073] Detect the actual liquid level of the heating water tank w 2 and the actual water temperature t 1 ;

[0074] Determine whether to heat the actual liquid level of the water tank 2 ≥Set the upper limit of heating level w 2,1 And the actual water temperature of the heating water tank is t 1 ≥Set the upper limit temperature of heating 1,2 ;

[0075] If yes, it means that the water temperature and water level in the heating water tank are sufficient to meet the hot water replenishment demand of the insulation water tank, so the heat pump unit is turned off;

[0076] If not, it means that the water temperature or water level in the heating water tank is insufficient to meet the hot water replenishment demand of the insulation water tank, so the heat pump unit is turned on to heat the water sent to the insulation water tank.

[0077] The benefit of this design is that it can monitor the actual liquid level of the heating water tank in real time. 2 and the actual water temperature t 1 The system can intelligently decide when to shut down or start the heat pump unit. When the heating water tank can meet the hot water replenishment demand, shutting down the heat pump unit can reduce unnecessary energy consumption. When the heating water tank cannot meet the hot water replenishment demand, turning on the heat pump unit can ensure that the hot water in the insulation water tank is effectively replenished, achieving energy-saving and high-efficiency effects.

[0078] As a preferred solution, controlling the heat pump unit to be turned on or off according to the working parameters of the heating water tank also includes: after turning off the heat pump unit, determining whether the actual water temperature t of the insulation water tank is 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 , if not, continue to perform the hot water replenishment action.

[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 replenishment demand of the insulation water tank can be met. Therefore, it is directly judged whether the hot water in the insulation water tank is replenished, without the need to analyze the status of the heating water tank in the middle, which simplifies the control logic.

[0080] As a preferred solution, controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank also includes:

[0081] After starting the heat pump unit, check the actual liquid level of the heating water tank. 2 and the actual water temperature t 1 ;

[0082] Determine whether to heat the actual liquid level of the water tank 2 <Set the lower limit of heating level w 2,0 Or the actual water temperature of the heating tank t 1 <Set the lower limit temperature of heating 1,0 ;

[0083] If yes, it means that the water temperature or water level of the heating water tank is too low, so the hot water replenishment action is stopped, and the heating action and / or water replenishment action is selected to heat and / or replenish the heating water tank in time;

[0084] If not, it means that the water temperature of the heating water tank and the water temperature are normal. At this time, it can be determined whether the actual water temperature of the insulation water tank is t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 If not, the amount of hot water in the insulated water tank is still insufficient, and the hot water replenishment action continues.

[0085] This design monitors the actual liquid level of the heating water tank during the process of adding hot water to the insulation water tank when the water level in the heating water tank has not reached the upper limit. 2 and the actual water temperature t 1 , when the water temperature or water level is insufficient, heating and / or water replenishment actions are performed. The condensing side of the heat pump unit heats the low-temperature water flowing out of the heating water tank, increasing the heat exchange temperature difference on the condensing side to achieve efficient heat production management. After the water temperature and water level of the heating water tank are in place, hot water is added to the insulation water tank to improve the water temperature stability of the insulation water tank and improve the energy efficiency of the hot water system.

[0086] like Figure 3 , 4 As shown, on this basis, in some feasible embodiments of the present invention, selecting to perform a heating action and / or a water replenishment action on the heating water tank includes:

[0087] When the actual liquid level of the heating water tank is w 2<Set the lower limit of heating level w 2,0 When the water supply is too low, the water supply action is executed, the pressure difference water supply pipe is shut off (the switch valve is closed), and the external water supply pipe is connected to supply water to the heating water tank (the water supply valve is opened);

[0088] When the actual water temperature of the heating water tank is t 1 <Set the lower limit temperature of heating 1,0 When the heating action is executed, the pressure difference water supply pipe is cut off (the switch valve is closed), the first pump unit and the heat pump unit are turned on, and the water outlet side of the heat pump unit is connected to the heating water tank.

[0089] The purpose of this design is to turn on the heat pump unit and the external water supply pipe to heat and replenish the heating water tank when the water temperature or water level in the heating water tank is insufficient, so that there is sufficient hot water in the heating water tank to supply the insulation water tank.

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

[0091] First determine whether to heat the actual liquid level of the water tank w 2 <Set the lower limit of heating level w 2,0 ;

[0092] If yes, it means that the water level in the heating water tank is too low. Perform water replenishment, close the pressure difference water replenishment pipe (close the switch valve), connect the external water replenishment pipe to replenish water to the heating water tank (open the water replenishment valve), until the actual liquid level of the heating water tank reaches w 2 ≥Set the upper limit of heating level w 2,1 , and then determine whether to heat the actual water temperature of the water tank t 1 <Set the lower limit temperature of heating 1,0 If it is, it means that the water temperature of the heating water tank is too low. Perform the heating action, close the pressure difference water supply pipe (close the switch valve), start the first pump unit and the heat pump unit, and connect the water outlet side of the heat pump unit to the heating water tank (open the heating valve and close the insulation valve) until the actual water temperature of the heating water tank reaches t 1 ≥Set the upper limit temperature of heating 1,2 At this time, the water temperature and water level of the heating water tank are sufficient, and the actual water temperature t of the insulation water tank is re-tested. 2 and the actual liquid level w 1 ;

[0093] If not, it means that the remaining water in the heating water tank can meet the hot water replenishment demand of the insulation water tank. 1 <Set the lower limit temperature of heating 1,0 If not, it means that the water volume and water temperature in the heating water tank can meet the hot water replenishment demand of the insulation water tank, and return to re-test the actual water temperature of the insulation water tank t 2 and the actual liquid level w 1If yes, it means the water temperature in the heating water tank is too low. Execute the heating action, shut off the differential pressure water supply pipe (close the switch valve), start the first pump unit and the heat pump unit, and connect the outlet side of the heat pump unit to the heating water tank (open the heating valve and close the insulation valve) until the actual water temperature of the heating water tank reaches t 1 ≥Set the upper limit temperature of heating 1,2 At this time, the water volume and water temperature of the heating water tank can meet the hot water replenishment demand of the insulation water tank, and return to re-detect the actual water temperature of the insulation water tank t 2 and the actual liquid level w 1 .

[0094] This design can restore the water level and water temperature in the heating water tank to a state where hot water can be added to the insulation water tank as soon as possible. When the water level and water temperature in the heating water tank are appropriate, the actual liquid level w 2 ≥Set the lower limit of heating level w 2,0 The actual water temperature t 1 ≥Set the lower limit temperature of heating 1,0 You can return to re-check the actual water temperature of the insulation water tank 2 and the actual liquid level w 1 , shorten the waiting time of the insulated water tank and ensure that the hot water needs of users are met.

[0095] like Figure 5 As shown, as a preferred solution, the control method also includes:

[0096] Determine whether the actual water temperature of the insulation water tank is t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 If yes, it means that there is enough hot water in the insulated water tank, and the second pump group is turned on or off according to the working parameters on the outlet side of the insulated water tank.

[0097] Since the outlet side of the insulated water tank is connected to the user end, after the hot water in the insulated water tank is sufficient, the water storage situation of the outlet side pipeline can be discovered in time by monitoring the outlet side working parameters of the insulated water tank, and then the second pump group can be turned on to drive the water between the insulated water tank and the pipeline to circulate, and the hot water can be added to the outlet side pipeline of the insulated water tank, ensuring that each user end has instant hot water when in use, thereby improving the user experience.

[0098] On this basis, in some feasible embodiments of the present invention, controlling the opening or closing of the second pump group according to the working parameters of the outlet side of the thermal insulation water tank includes:

[0099] Detect the outlet pipe network pressure p of the insulation water tank 1 ;

[0100] Determine whether the outlet pipe pressure of the insulated water tank is 1 <Set lower limit pressure p 0 ;

[0101] If yes, it means that the water pressure at the outlet of the insulated water tank is too low and the water volume is insufficient. When the user needs hot water, water cannot be immediately supplied. Turn on the second pump group to send water back to the insulated water tank (open the insulation valve) until the outlet pipe pressure p 1 ≥Set upper limit pressure p 2 At this time, the return water temperature t at the outlet of the insulation water tank is detected 3 , when the return water temperature at the outlet of the insulation water tank is t 3 ≥Set return water temperature t 3,0 When the pressure of the outlet pipe network of the insulated water tank is sufficient and the water temperature is moderate, the second pump group is turned off, and the water is stopped from being sent back to the insulated water tank (the insulation valve is closed). The pressure of the outlet pipe network of the insulated water tank is re-tested. 1 ;

[0102] If not, it means that the water pressure at the outlet of the thermal insulation water tank is moderate, the water volume is appropriate, and the user can immediately supply water when there is a demand for hot water. At this time, the return water temperature t at the outlet of the thermal insulation water tank is detected. 3 , when the return water temperature at the outlet of the insulation water tank is t 3 ≥Set return water temperature t 3,0 When the pressure and volume of the pipe network at the outlet of the insulated water tank are both moderate, turn off the second pump group, stop sending water back to the insulated water tank (close the insulation valve), and return to re-test the pressure p of the pipe network at the outlet of the insulated water tank. 1 .

[0103] This design detects the outlet side pipe network pressure p 1 and the return water temperature at the outlet side t 3 , so that there is sufficient hot water stored in the outlet pipe network to ensure the user experience. At the same time, due to the lack of water pressure on the outlet side, the amount of water in the return pipe is small, and the return water temperature t 3 It cannot reflect the actual water temperature in the pipe network. After increasing the water pressure on the outlet side, the return water temperature on the outlet side is detected. 3 Can improve control accuracy.

[0104] like Figure 5 As shown, as a preferred method, the control method also includes:

[0105] Detect the return water temperature t at the outlet of the insulation water tank 3 Afterwards, when the return water temperature at the outlet of the insulation water tank is 3 <Set return water temperature t 3,0 When the water temperature of the outlet pipe network is still low, it is necessary to judge whether the actual water temperature of the insulation water tank is t 2 ≥Set the lower limit temperature of insulation2,0 And the actual liquid level of the insulation water tank w 1 ≥Set the lower limit of insulation level w 1,0 ;

[0106] If yes, it means that the water volume and water temperature in the insulation water tank can meet the return water temperature increase requirements. Turn off the second pump group, stop sending water back to the insulation water tank (close the insulation valve), and return to re-test the outlet side pipe network pressure p of the insulation water tank. 1 ;

[0107] If not, it means that the water volume and water temperature in the insulation water tank cannot meet the return water temperature increase requirements, and hot water replenishment is performed until the actual water temperature of the insulation water tank reaches t 2 ≥Set the upper limit temperature of insulation 2,1 And the actual liquid level of the insulation water tank w 1 ≥Set the upper limit of insulation level w 1,1 , turn off the second pump group, stop sending water back to the insulation water tank (close the insulation valve), return to re-test the outlet side pipe network pressure p of the insulation water tank 1 .

[0108] The advantage of this design is that it can accurately identify the reason why the outlet side pipe network temperature is low. By re-testing the outlet side working parameters of the insulated water tank or adding hot water to the insulated water tank, the water volume and water temperature of the outlet side pipe network can be effectively increased.

[0109] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. When the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. The order of execution of actions, steps, etc. in the devices and methods shown in the specification and the accompanying drawings can be implemented in any order as long as there is no special explicit limitation on the order and the output of the previous processing is not used in the subsequent processing. Similar terms of order used for the convenience of description do not mean that they must be implemented in such an order.

[0110] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Double water tank hot water system, including: An insulated water tank, a heating water tank and a heat pump unit, wherein the outlet side of the insulated water tank is connected to the user end through a second pump unit, a pressure difference 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; It is characterized in that 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 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 insulation water tank.

2. The dual water tank hot water system 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. Wherein, 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 connection state of the water outlet side of the heat pump unit is switched by the heating valve and the insulation valve.

3. The dual water tank hot water system 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 installed with check valves that only allow liquid to flow to the insulated water inlet pipe.

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

5. A control method for a dual-tank hot water system, the control method being applied to the dual-tank hot water system according to any one of claims 1 to 4, characterized in that: include: 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, and control the heat pump unit to turn on or off according to the working parameters of the heating water tank.

6. The control method according to claim 5, characterized in that: Controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank includes: Detecting the actual liquid level w2 and the actual water temperature t1 of the heating water tank; Determine whether 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 The actual water temperature of the heating water tank t1 ≥ the set upper limit temperature of heating t 1,2 ; If yes, shut down the heat pump unit; If not, the heat pump unit is turned on.

7. The control method according to claim 6, characterized in that: Controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank also includes: After the heat pump unit is turned off, it is determined whether the actual water temperature t2 of the insulation water tank is greater than the set insulation upper limit temperature t 2,1 And the actual liquid level w1 of the insulation water tank ≥ the set insulation upper limit liquid level w 1,1 , if not, continue to perform the hot water replenishment action.

8. The control method according to claim 6, characterized in that: Controlling the heat pump unit to turn on or off according to the working parameters of the heating water tank also includes: After starting the heat pump unit, detecting the actual liquid level w2 and the 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, 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 insulation water tank ≥ the set insulation upper limit liquid level w 1,1 , if not, continue to perform the hot water replenishment action.

9. The control method according to claim 7 or 8, characterized in that: The control method further comprises: 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 insulation water tank ≥ the set insulation upper limit liquid 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.

10. The control method according to claim 9, 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; 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 is too low, 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.

11. The control method according to claim 10, characterized in that: The control method further comprises: 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 or equal to the set thermal insulation lower limit temperature t 2,0 And the actual liquid level w1 of the insulation water tank ≥ the set insulation lower limit liquid level w 1,0 ; If yes, then 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; 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 insulation water tank ≥ the set insulation upper limit liquid 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.

12. The control method according to claim 8, characterized in that: Selecting to perform a heating action and / or a water replenishment 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 turned off, the water supply pipe is turned off, and the external water supply pipe is turned on 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 unit and the heat pump unit are turned on, and the water outlet side of the heat pump unit is connected to the heating water tank.

13. The control method according to claim 12, characterized in that: Selecting to perform a heating action and / or a water replenishment 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 ≥ 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 ≥ the set upper limit temperature t 1,2 , return to re-detect the actual water temperature t2 and the 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 heating 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 the actual liquid level w1 of the insulated water tank.

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