Control method and control system of dual-energy water heating device

Abstract

The invention discloses a control method and system of a dual-energy water heating device. The method at least comprises the following working modes according to user requirements: when a user aims at meeting a large amount of hot water requirements, a comfortable mode can be adopted; a user expected water use temperature Ts, a water tank upper part actual temperature Tu, a water tank lower part actual temperature Td, a gas heating return difference temperature Ta and a heat pump heating return difference temperature Tb are respectively obtained; when Td is smaller than or equal to Ts-Tb, the heat pump system is started to heat the water tank, and when Td is larger than or equal to Ts, the heat pump system is closed, and the previous step is executed again; and when Tu is smaller than or equal to Ts-Ta, a gas system is started to heat the water tank, and when Tu is larger than or equal to Ts, the gas system is closed, and the previous steps are returned. The dual-energy water heating device can be automatically controlled to operate in the most suitable heating mode in response to different requirements of users and external environment conditions. And in different operation modes, the use ratio of the heat pump to the fuel gas is dynamically adjusted, and the overall energy efficiency of the system is improved to the maximum extent while it is ensured that the user requirements are met.

Description

Technical Field

[0001] The invention relates to the technical field of water heaters, and in particular to a control method and a control system for a dual-energy water heater. Background Art

[0002] Heat pump water heaters and gas water heaters are two common types of water heaters on the market, each with its own unique advantages. Heat pump water heaters heat water by absorbing heat from the environment, have a high energy efficiency ratio (COP), and can usually provide sufficient hot water at a lower electricity consumption, which is particularly suitable for use during periods when electricity prices are low. However, heat pump water heaters usually heat up slowly, and their energy efficiency drops significantly when the ambient temperature is low. On the other hand, gas water heaters rely on natural gas as an energy source, and have the characteristics of fast heating speed and strong continuous heating capacity, which is particularly suitable for scenarios where a large amount of hot water is needed in a short period of time. However, the operating cost of gas water heaters depends on the price of natural gas, and certain carbon emissions will be generated during use.

[0003] As consumers' demand for diversified water use increases, as well as their requirements for energy efficiency and environmental protection, dual-energy water heater systems that combine heat pump water heaters with gas water heaters have begun to appear on the market. Such systems can intelligently select heat pumps or gas as heat sources based on different user needs and external environmental conditions, achieving higher energy efficiency and user experience. However, existing dual-energy water heater systems often have problems with complexity and lack of intelligence in their control methods, and are unable to automatically select the optimal heating mode based on the actual needs of users, resulting in poor user experience and difficulty in fully leveraging the advantages of dual-energy water heaters. Summary of the invention

[0004] The present invention aims to provide a control method and control system for automatically optimizing dual-energy heating modes and operating modes based on user needs and environmental conditions, in order to achieve the effects of meeting user needs, reducing energy consumption, and reducing carbon emissions.

[0005] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention includes:

[0006] The control method of the dual energy water heater device includes at least the following working modes according to user needs:

[0007] When the user aims to meet a large amount of hot water demand, the comfort mode can be adopted. The control method of the comfort mode includes:

[0008] S1. Obtain the user's expected water temperature Ts, the actual temperature of the upper part of the water tank Tu, the actual temperature of the lower part of the water tank Td, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb respectively;

[0009] S21, when Td≤Ts-Tb, start the heat pump system to heat the water tank until Td≥Ts, then turn off the heat pump system and return to step S1;

[0010] S22. When Tu≤Ts-Ta, start the gas system to heat the water tank until Tu≥Ts, then shut down the gas system and return to step S1.

[0011] Preferably, during the process of the heat pump system or the gas system heating the water tank, the heat pump system or the gas system is continuously detected to see if there is a fault. If so, the heat pump system or the gas system is shut down and an alarm is given to the user.

[0012] Preferably, when the user aims to minimize energy costs and meet basic hot water needs, the economic mode can be adopted, and the control method of the economic mode includes:

[0013] Obtain the unit price of electricity C1, unit price of natural gas C2 and current ambient temperature T1 for the current period; query the performance information of the heat pump system and the thermal efficiency η of the gas system;

[0014] The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value;

[0015] Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information;

[0016] When T1>T2 when the economic mode is started, the heat pump system is started to heat the water tank until T1≤T2-β, the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter;

[0017] When T1≤T2 when the economic mode is started, the gas system is started to heat the water tank until T1≥T2+β, the gas system is shut down and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

[0018] Preferably, when the user aims to minimize carbon emissions and meet basic hot water needs, the low-carbon mode can be adopted, and the control method of the low-carbon mode includes:

[0019] Obtain electricity carbon emission factor P1, natural gas carbon emission factor P2 and current ambient temperature T1; query heat pump system performance information and gas system thermal efficiency η;

[0020] The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目=α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value;

[0021] Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information;

[0022] When T1>T2 when the low-carbon mode is started, the heat pump system is started to heat the water tank until T1≤T2-β, the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter;

[0023] When T1≤T2 when the low-carbon mode is started, the gas system is started to heat the water tank until T1≥T2+β, the gas system is shut down and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

[0024] Preferably, the gas system opening temperature Tc and the gas system closing temperature Te are set, and when T1>T2 and Tu≤Tc, the gas system is started to heat the water tank until Tu≥Te; wherein 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

[0025] The present invention also provides a control system for a dual energy water heater, comprising:

[0026] A control panel, used to receive a desired water temperature Ts and an operation mode selection input by a user, wherein the operation modes include at least a comfort mode, an economic mode and a low-carbon mode;

[0027] The temperature acquisition module is used to respectively acquire the actual temperature Tu of the upper part of the water tank, the actual temperature Td of the lower part of the water tank, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb;

[0028] The controller is connected to the control panel and the temperature acquisition module respectively, and is configured as follows:

[0029] When the user selects the comfort mode with the goal of meeting a large demand for hot water, the controller continuously acquires the temperature data transmitted by the temperature acquisition module; when Td≤Ts-Tb, the controller controls the heat pump system to start heating the water tank until Td≥Ts, at which time the controller controls the heat pump system to shut down and continues to acquire the temperature data; when Tu≤Ts-Ta, the controller controls the gas system to start heating the water tank until Tu≥Ts, at which time the controller controls the gas system to shut down and continues to acquire the temperature data.

[0030] Preferably, it also includes an economic parameter acquisition module, which is connected to the controller and is used to obtain the unit price of electricity C1, the unit price of natural gas C2 and the current ambient temperature T1 in the current period, and query the performance information of the heat pump system and the thermal efficiency η of the gas system;

[0031] The controller is also configured to select the economic mode when the user aims to minimize energy costs and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2;

[0032] When T1>T2 when the economic mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the economic mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

[0033] Preferably, it also includes an economic parameter acquisition module, which is connected to the controller and is used to obtain the carbon emission factor P1 of electricity, the carbon emission factor P2 of natural gas and the current ambient temperature T1, and query the performance information of the heat pump system and the thermal efficiency η of the gas system;

[0034] The controller is also configured to select the low carbon mode when the user aims to minimize carbon emissions and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2;

[0035] When T1>T2 when the low-carbon mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the low-carbon mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

[0036] Preferably, it also includes a fault detection module, which is configured to continuously detect whether there is a fault in the heat pump system or the gas system during the process of the heat pump system or the gas system heating the water tank. If so, a shutdown command is sent to the controller to shut down the heat pump system or the gas system, and an alarm is given to the user.

[0037] Preferably, the controller has a built-in gas system opening temperature Tc and a gas system closing temperature Te. When T1>T2 and Tu≤Tc, the controller controls the gas system to start heating the water tank until Tu≥Te; wherein 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

[0038] Beneficial Effects

[0039] The present invention can respond to different needs of users and external environmental conditions, and automatically control the dual-energy water heater to operate in the most suitable heating mode. In different operating modes, the use ratio of heat pump and gas is dynamically adjusted to ensure that the overall energy efficiency of the system is maximized while meeting user needs. The present invention not only effectively reduces the total energy consumption, but also significantly reduces the user's use cost and avoids unnecessary energy waste, thereby achieving a more economical and environmentally friendly hot water supply, and improving energy utilization efficiency and reducing environmental burden. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of a control method of a dual energy water heater in a comfort mode provided in a preferred embodiment of the present invention;

[0041] Figure 2 It is a flow chart of a control method of a dual energy water heater in an economic mode provided in a preferred embodiment of the present invention;

[0042] Figure 3 A schematic flow chart of a control method of a dual-energy water heater in a low-carbon mode provided in a preferred embodiment of the present invention;

[0043] Figure 4A heat pump performance curve diagram of a dual-energy water heating device is provided in another preferred embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the control system structure of a dual-energy water heating device provided in another preferred embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0046] Example 1

[0047] The dual-energy water heater device refers to a water heater device that can use two different energy sources for heating at the same time. In this field, it can refer to at least two of a heat pump water heater device, a gas water heater device, and an electric water heater device. In the present invention, the clean energy air energy heat pump is the main one, and the traditional energy natural gas is the auxiliary one. The two systems operate independently and do not interfere with each other.

[0048] like Figure 1 As shown, this embodiment provides a control method for a dual-energy water heater, which includes at least the following working modes according to user needs:

[0049] When the user aims to meet a large amount of hot water demand, the comfort mode can be adopted. The control method of the comfort mode includes:

[0050] S1. Obtain the user's expected water temperature Ts, the actual temperature of the upper part of the water tank Tu, the actual temperature of the lower part of the water tank Td, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb respectively;

[0051] S21, when Td≤Ts-Tb, start the heat pump system to heat the water tank until Td≥Ts, then turn off the heat pump system and return to step S1;

[0052] S22. When Tu≤Ts-Ta, start the gas system to heat the water tank until Tu≥Ts, then shut down the gas system and return to step S1.

[0053] In this embodiment, the start-up condition of the heat pump system is that the temperature of the lower part of the water tank decreases. At this time, although the temperature of the lower part of the water tank decreases, there is still sufficient hot water stored in the water tank. The heat pump system will intervene at this time, and by slowly heating the water in the entire water tank, efficient energy utilization is achieved, ensuring that energy is saved to the maximum extent while meeting the instantaneous large-scale water demand. The start-up condition of the gas system is that the temperature of the upper part of the water tank decreases. At this time, the hot water in the water tank is about to be consumed, and the gas system will intervene quickly. The gas system has the characteristic of rapid heating. It will immediately heat the water in the upper part of the water tank to ensure that users can still get enough hot water supply when the demand for hot water is large.

[0054] In this mode, the present invention takes meeting the user's large demand for hot water as the primary premise, while fully considering the heating characteristics of the heat pump system and the gas system and the changing characteristics of the water temperature in the water tank. Specifically, although the heat pump system has a high energy utilization efficiency, its power is relatively low, so it has certain limitations in terms of rapid heat replenishment and cannot meet the user's instantaneous demand for a large amount of hot water in a short period of time. Therefore, the heat pump system is mainly used as the main heating method in a non-water use state or a small amount of water use state. Through a long period of slow heating, the water temperature in the water tank is kept stable to achieve energy-saving effects.

[0055] On the other hand, the gas system has the characteristic of rapid heating, which can quickly raise the water temperature when users need a large amount of hot water. However, the heating characteristics of the gas system determine that it cannot effectively heat the water in the entire water tank, which easily leads to obvious stratification of hot and cold water in the water tank. When users use hot water, the water temperature changes rapidly, and the gas system works longer and continuously emits carbon dioxide (CO 2 ), which is relatively not environmentally friendly. Nevertheless, the gas system can provide sufficient hot water supply when users use a lot of water instantly, making up for the shortcomings of the heat pump system.

[0056] This mode cleverly combines the advantages of the heat pump system and the gas system to achieve a balance between energy efficiency and performance. Under normal circumstances, the heat pump system operates as a normal heating mode to maintain the basic water temperature in the water tank. When users need a large amount of hot water, the gas system quickly intervenes to provide rapid heat replenishment to meet high-demand hot water usage scenarios. It is worth noting that in this mode, the control processes of the heat pump system and the gas system are independent of each other, that is, the opening and closing operations of one will not directly affect the opening and closing of the other. This design ensures that the two systems can operate flexibly and efficiently, each playing to its own strengths, while avoiding interference between systems and achieving a stable and reliable hot water supply.

[0057] In some preferred embodiments, in order to ensure the normal operation of the dual energy, a fault detection mechanism is also provided. Specifically, in the process of the heat pump system or the gas system heating the water tank, the heat pump system or the gas system is continuously detected to see if there is a fault. If so, the heat pump system or the gas system is shut down and an alarm is given to the user. In other preferred embodiments, before the dual energy water heater is powered on and starts to enter the working state, the system can also set a corresponding fault detection or elimination mechanism to ensure that the system is in a normal working state when it is started. This type of fault detection and elimination mechanism is a conventional technology in the field, and the present invention does not further limit this. Obviously, in a dual energy system, if any heating system fails, in addition to shutting down the corresponding faulty system and giving an alarm, the system will automatically switch to another heating system that is operating normally to ensure the continuity and stability of the hot water supply. This design not only improves the reliability of the system, but also avoids the situation where the hot water supply is interrupted due to a single system failure, providing users with a safer and more stable use experience.

[0058] It should be noted that the comfort mode described in this embodiment constitutes the underlying control logic of the present invention, which serves as the basic operating framework of the system. On this basis, the control logic under different subsequent working modes (such as economic mode and low-carbon mode) is a supplement and extension of the underlying control logic. These supplementary logics are adjusted according to specific user needs and external conditions (such as electricity prices, gas prices, ambient temperature, etc.) to achieve more optimized energy management and cost control.

[0059] Therefore, the system is always based on the control logic of the comfort mode. When the user needs to meet a large amount of instantaneous hot water demand, the system will operate according to the control logic of the comfort mode. In other cases (such as non-water use or small water use), the system will select the corresponding control strategy according to the setting of the current mode, so as to provide the best hot water supply solution in different usage scenarios. Through this hierarchical control logic, the present invention ensures the organic unity of flexibility, efficiency and user experience.

[0060] Example 2

[0061] This embodiment is developed on the basis of the above-mentioned embodiment 1. Figure 2 As shown, this embodiment provides a dual-energy water heater control method in an economic mode with the goal of minimizing energy costs and meeting basic hot water needs, specifically including:

[0062] When the user aims to minimize energy costs and meet basic hot water needs, the economic mode can be used. The control method of the economic mode includes:

[0063] Obtain the unit price of electricity C1, the unit price of natural gas C2 and the current ambient temperature T1 for the current period; query the performance information of the heat pump system and the thermal efficiency η of the gas system. The performance information of the heat pump system is a basic parameter fixed when the dual-energy water heater is shipped from the factory, which is generally presented in the form of a COP curve. Similarly, the thermal efficiency η of the gas system is also a fixed parameter of the dual-energy water heater when it is shipped from the factory.

[0064] The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value. The following is an explanation of the thinking process of the calculation formula proposed in this embodiment:

[0065] The core goal of this model is to select the most suitable heating system for use based on the current electricity price, gas price and operating conditions to minimize energy consumption costs. To this end, it is necessary to find the critical condition where the cost is equal when using only the heat pump system and only the gas system. Specifically, by calculating the COP value (energy efficiency ratio) of the heat pump system, it can be determined under what circumstances the cost of using the two heating systems is the same, that is: C1 / COP 热目 =C2 / (α×η); After mathematical transformation, the target COP of the heat pump system is obtained 热目 Calculation formula. Those skilled in the art will know that the calorific value of natural gas per cubic meter is generally between 8000 kcal and 8500 kcal, and 1 kcal is equal to 4.1868 kJ. Therefore, the calorific value of natural gas per cubic meter is between 33494.4 kJ and 35587.8 kJ. The calorific value of 1 kWh is 850 kilocalories, which is equivalent to 3.6×10^3 kJ. Therefore, the heat energy generated by the combustion of each cubic meter of natural gas is equivalent to the heat energy generated by 9.3 to 9.88 kWh. Therefore, α can be taken between 9.3 and 9.88, and preferably, the middle value of 9.6 can be taken.

[0066] Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information;

[0067] When T1>T2 when the economic mode is started, the actual COP value of the heat pump system during operation is higher than the COP 热目At this time, the cost of using the heat pump system for heating is lower than that of using the gas system. Therefore, the heat pump system should be used to heat the water tank first until T1≤T2-β, then the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated, where β is the ambient temperature adjustment parameter. It should be understood that the switching conditions of the heat pump system and the gas system in the subsequent time are set to a certain temperature hysteresis to avoid the possibility of frequent switching of the dual system heat sources due to changes in ambient temperature, thereby ensuring that the entire dual energy water heating device can operate stably. β defaults to 2. If the temperature at the installation location of the dual energy water heating device changes rapidly, the β value can be appropriately increased.

[0068] When the economic mode is started, T1≤T2, the actual COP value of the heat pump system during operation is lower than the COP 热目 At this time, the cost of using the heat pump system for heating is higher than that of using the gas system. Therefore, the gas system should be used to heat the water tank first until T1≥T2+β, then the gas system is turned off and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

[0069] The following is a further explanation using an actual case.

[0070] Commercial electricity in a certain place is 0.86 yuan / kW.h, and commercial gas is 3.23 yuan / m 3 , the thermal efficiency of the gas engine is 105%, α is 9.6, and the COP can be calculated: 热目 =9.6*105%*0.86 / 3.23≈2.7, Figure 4 The heat pump performance curve shown in the figure shows that the corresponding target ambient temperature is about 4°C. This means that when the ambient temperature is higher than 4°C, the actual COP value of the heat pump system is usually higher than 2.7, so the heat pump system should be used to heat the water tank to achieve higher energy efficiency and cost savings. On the contrary, when the ambient temperature is lower than 4°C, the actual COP value of the heat pump system may be lower than 2.7, and the gas system should be switched to for heating. In this case, the gas system can provide a more stable and efficient heating effect, ensuring that the user's hot water needs are met in a timely manner.

[0071] It should be understood that the above control logic is applicable to heating control in a non-water state or a small amount of water state. When the system is in these states, based on the ambient temperature and the actual COP value of the heat pump system, the system will automatically switch between the heat pump system and the gas system to maximize energy efficiency. However, when the user needs a larger instantaneous hot water supply, the system should automatically switch to the conventional control method provided in Example 1. In this case, the gas system will be started first to ensure that the user's hot water demand can be met in a timely manner, while the heat pump system continues to serve as an auxiliary heating method to ensure a continuous and sufficient supply of hot water.

[0072] Example 3

[0073] This embodiment is developed on the basis of the above-mentioned embodiment 1. Figure 3 As shown, this embodiment provides a dual-energy water heater control method in a low-carbon mode with the goal of minimizing carbon emissions and meeting basic hot water needs, specifically including:

[0074] When the user aims to minimize carbon emissions and meet basic hot water needs, the low-carbon mode can be adopted. The control method of the low-carbon mode includes:

[0075] Obtain the electricity carbon emission factor P1, natural gas carbon emission factor P2 and current ambient temperature T1; query the heat pump system performance information and gas system thermal efficiency η. Among them, the electricity carbon emission factor P1 depends on the local power source and can generally be obtained automatically through networking or manually input. The natural gas carbon emission factor P2 represents 1m 3 According to existing technology, the CO2 emission after natural gas combustion is 1.9 kg / m 3 , technicians in this field can make manual corrections based on this.

[0076] The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目 =α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value. The following is an explanation of the thinking process of the calculation formula proposed in this embodiment:

[0077] The core goal of this model is to select the most suitable heating system for use based on the local electricity carbon emission factor and operating conditions to minimize carbon emissions. To this end, it is necessary to find the critical condition where carbon emissions are equal when only the heat pump system is used and when only the gas system is used. Specifically, P1 / COP 热目 =P2 / (α×η); After mathematical transformation, the target COP of the heat pump system is obtained 热目 The calculation formula for .

[0078] Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information;

[0079] When T1>T2 when the low carbon mode is started, the actual COP value of the heat pump system during operation is higher than the COP 热目At this time, the carbon emission of using the heat pump system for heating is lower than that of using the gas system, so the heat pump system should be used to heat the water tank first, until T1≤T2-β, then the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated; where β is the ambient temperature adjustment parameter;

[0080] When T1≤T2 when the low carbon mode is started, the actual COP value of the heat pump system during operation is lower than the COP 热目 At this time, the carbon emissions of using the heat pump system for heating are higher than those of using the gas system. Therefore, the gas system should be used to heat the water tank first until T1≥T2+β, then the gas system is turned off and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

[0081] The following is a further explanation using an actual case.

[0082] The carbon emission factor of electricity in a certain place is 0.45kgCO2 / kWh, and the carbon emission of natural gas is 1.9kgCO2 / m 3 , the thermal efficiency of the gas engine is 105%, α is 9.6, and the COP can be calculated: 热目 =9.6*105%*0.45 / 1.9≈2.4, Figure 4 The heat pump performance curve shown in the figure shows that the corresponding target ambient temperature is about 2°C. This means that when the ambient temperature is higher than 2°C, the actual COP value of the heat pump system is usually higher than 2.4, so the heat pump system should be used to heat the water tank to achieve higher energy efficiency and reduce carbon emissions. On the contrary, when the ambient temperature is lower than 2°C, the actual COP value of the heat pump system may be lower than 2.4. At this time, the gas system should be switched to for heating. In this case, the gas system can provide a more stable and efficient heating effect, ensuring that the user's hot water needs are met in a timely manner.

[0083] It should be understood that the above control logic is applicable to heating control in a non-water state or a small amount of water state. When the system is in these states, based on the ambient temperature and the actual COP value of the heat pump system, the system will automatically switch between the heat pump system and the gas system to achieve the lowest carbon emissions. However, when the user requires a larger instantaneous hot water supply, the system should automatically switch to the conventional control method provided in Example 1. In this case, the gas system will be started first to ensure that the user's hot water demand can be met in a timely manner, while the heat pump system continues to serve as an auxiliary heating method to ensure a continuous and sufficient supply of hot water.

[0084] Example 4

[0085] This embodiment is developed on the basis of the above-mentioned embodiment 2 or 3. Considering that in the above-mentioned economic mode or low-carbon mode, when the ambient temperature is low, the water temperature in the water tank may decrease by a greater margin than the heating capacity of the heat pump system. At this time, the water temperature in the water tank will inevitably continue to decrease or even be far lower than the user's expected water temperature. Even if the gas system is used for heating at this time, the water temperature will rise slowly or fluctuate greatly, thereby affecting the user experience or even damaging the dual-energy water heater. Therefore, it is necessary to set a forced pre-start and close mechanism for the gas system, which specifically includes:

[0086] Set the gas system opening temperature Tc and the gas system closing temperature Te. When T1>T2 and Tu≤Tc, start the gas system to heat the water tank until Tu≥Te; 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

[0087] Example 5

[0088] like Figure 5 As shown, this embodiment also provides a control system for a dual energy water heater, including:

[0089] A control panel, used to receive a desired water temperature Ts and an operation mode selection input by a user, wherein the operation modes include at least a comfort mode, an economic mode and a low-carbon mode;

[0090] The temperature acquisition module is used to respectively acquire the actual temperature Tu of the upper part of the water tank, the actual temperature Td of the lower part of the water tank, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb;

[0091] The controller is connected to the control panel and the temperature acquisition module respectively, and is configured as follows:

[0092] When the user selects the comfort mode with the goal of meeting a large demand for hot water, the controller continuously acquires the temperature data transmitted by the temperature acquisition module; when Td≤Ts-Tb, the controller controls the heat pump system to start heating the water tank until Td≥Ts, at which time the controller controls the heat pump system to shut down and continues to acquire the temperature data; when Tu≤Ts-Ta, the controller controls the gas system to start heating the water tank until Tu≥Ts, at which time the controller controls the gas system to shut down and continues to acquire the temperature data.

[0093] In some preferred embodiments, an economic parameter acquisition module is further included, which is connected to the controller and is used to obtain the unit price of electricity C1, the unit price of natural gas C2 and the current ambient temperature T1 in the current period, and query the performance information of the heat pump system and the thermal efficiency η of the gas system;

[0094] The controller is also configured to select the economic mode when the user aims to minimize energy costs and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2.

[0095] When T1>T2 when the economic mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the economic mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

[0096] In some preferred embodiments, an economic parameter acquisition module is included, connected to the controller, for acquiring the carbon emission factor P1 of electricity, the carbon emission factor P2 of natural gas and the current ambient temperature T1, and querying the performance information of the heat pump system and the thermal efficiency η of the gas system;

[0097] The controller is also configured to select the low carbon mode when the user aims to minimize carbon emissions and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2.

[0098] When T1>T2 when the low-carbon mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the low-carbon mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

[0099] In some preferred embodiments, a fault detection module is also included, which is configured to continuously detect whether there is a fault in the heat pump system or the gas system during the process of the heat pump system or the gas system heating the water tank. If so, a shutdown command is sent to the controller to shut down the heat pump system or the gas system, and an alarm is given to the user.

[0100] In some preferred embodiments, the controller has built-in gas system opening temperature Tc and gas system closing temperature Te. When T1>T2 and Tu≤Tc, the controller controls the gas system to start heating the water tank until Tu≥Te; wherein 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

[0101] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A control method for a dual energy water heater, characterized in that: According to user needs, it includes at least the following working modes: When the user aims to meet a large amount of hot water demand, the comfort mode can be adopted. The control method of the comfort mode includes: S1. Obtain the user's expected water temperature Ts, the actual temperature of the upper part of the water tank Tu, the actual temperature of the lower part of the water tank Td, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb respectively; S21, when Td≤Ts-Tb, start the heat pump system to heat the water tank until Td≥Ts, then turn off the heat pump system and return to step S1; S22. When Tu≤Ts-Ta, start the gas system to heat the water tank until Tu≥Ts, then shut down the gas system and return to step S1.

2. The control method of the dual energy water heater according to claim 1, characterized in that: When the heat pump system or the gas system is heating the water tank, the heat pump system or the gas system is continuously checked for faults. If so, the heat pump system or the gas system is shut down and an alarm is given to the user.

3. The control method of the dual energy water heater according to claim 1, characterized in that: When the user aims to minimize energy costs and meet basic hot water needs, the economic mode can be used. The control method of the economic mode includes: Obtain the unit price of electricity C1, unit price of natural gas C2 and current ambient temperature T1 for the current period; query the performance information of the heat pump system and the thermal efficiency η of the gas system; The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information; When T1>T2 when the economic mode is started, the heat pump system is started to heat the water tank until T1≤T2-β, the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; When T1≤T2 when the economic mode is started, the gas system is started to heat the water tank until T1≥T2+β, the gas system is shut down and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

4. The control method of the dual energy water heater according to claim 1, characterized in that: When the user aims to minimize carbon emissions and meet basic hot water needs, the low-carbon mode can be adopted. The control method of the low-carbon mode includes: Obtain electricity carbon emission factor P1, natural gas carbon emission factor P2 and current ambient temperature T1; query heat pump system performance information and gas system thermal efficiency η; The target COP of the heat pump system is calculated by the following formula 热目 :COP 热目 =α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; Query the COP 热目 a target ambient temperature T2 corresponding to the heat pump system performance information; When T1>T2 when the low-carbon mode is started, the heat pump system is started to heat the water tank until T1≤T2-β, the heat pump system is turned off and the gas system is started to heat the water tank until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; When T1≤T2 when the low-carbon mode is started, the gas system is started to heat the water tank until T1≥T2+β, the gas system is shut down and the heat pump system is started to heat the water tank until T1≤T2, and this step is repeated.

5. The control method of the dual energy water heater according to claim 3 or 4, characterized in that: Set the gas system opening temperature Tc and the gas system closing temperature Te. When T1>T2 and Tu≤Tc, start the gas system to heat the water tank until Tu≥Te; 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

6. The control system of the dual energy water heater is characterized by: include: A control panel, used to receive a desired water temperature Ts and an operation mode selection input by a user, wherein the operation modes include at least a comfort mode, an economic mode and a low-carbon mode; The temperature acquisition module is used to respectively acquire the actual temperature Tu of the upper part of the water tank, the actual temperature Td of the lower part of the water tank, the gas heating hysteresis temperature Ta and the heat pump heating hysteresis temperature Tb; The controller is connected to the control panel and the temperature acquisition module respectively, and is configured as follows: When the user selects the comfort mode with the goal of meeting a large demand for hot water, the controller continuously obtains the temperature data transmitted by the temperature acquisition module; when Td≤Ts-Tb, the controller controls the heat pump system to start heating the water tank until Td≥Ts, at which time the controller controls the heat pump system to shut down and continues to obtain the temperature data; when Tu≤Ts-Ta, the controller controls the gas system to start heating the water tank until Tu≥Ts, at which time the controller controls the gas system to shut down and continues to obtain the temperature data.

7. The control system of the dual energy water heater according to claim 6, characterized in that: It also includes an economic parameter acquisition module, which is connected to the controller and is used to obtain the unit price of electricity C1, the unit price of natural gas C2 and the current ambient temperature T1 in the current period, and query the performance information of the heat pump system and the thermal efficiency η of the gas system; The controller is also configured to select the economic mode when the user aims to minimize energy costs and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×C1 / C2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2; When T1>T2 when the economic mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the economic mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

8. The control system of the dual energy water heater according to claim 6, characterized in that: It also includes an economic parameter acquisition module, which is connected to the controller and is used to obtain the carbon emission factor P1 of electricity, the carbon emission factor P2 of natural gas and the current ambient temperature T1, and query the performance information of the heat pump system and the thermal efficiency η of the gas system; The controller is also configured to select the low carbon mode when the user aims to minimize carbon emissions and meet basic hot water needs. The controller has a built-in heat pump system target COP. 热目 Calculation formula: COP 热目 =α×η×P1 / P2; where α is a dimensionless parameter, representing the calorific value of each cubic meter of natural gas combustion and the amount of electricity consumed by the heat pump system to produce equivalent calorific value; the controller obtains various parameters to calculate the target COP of the heat pump system 热目 , and query the COP in the heat pump system performance information 热目 The corresponding target ambient temperature T2; When T1>T2 when the low-carbon mode is started, the controller controls the heat pump system to start heating the water tank, until T1≤T2-β, the controller controls the heat pump system to shut down and controls the gas system to start heating the water tank, until T1>T2, and this step is repeated; wherein β is the ambient temperature adjustment parameter; when T1≤T2 when the low-carbon mode is started, the controller controls the gas system to start heating the water tank, until T1≥T2+β, the controller controls the gas system to shut down and controls the heat pump system to start heating the water tank, until T1≤T2, and this step is repeated.

9. The control system of the dual energy water heater according to claim 6, characterized in that: It also includes a fault detection module, which is configured to continuously detect whether there is a fault in the heat pump system or the gas system during the process of the heat pump system or the gas system heating the water tank. If so, a shutdown command is sent to the controller to shut down the heat pump system or the gas system, and an alarm is given to the user.

10. The control system of the dual energy water heater according to claim 7 or 8, characterized in that: The controller has built-in gas system opening temperature Tc and gas system closing temperature Te. When T1>T2 and Tu≤Tc, the controller controls the gas system to start heating the water tank until Tu≥Te; wherein 30℃≤Tc≤55℃, 35℃≤Te≤60℃, Te>Tc.

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