Method and device for calculating optimal temperature of intermediate medium of two-stage heat pump coupling heat supply system

Abstract

The invention provides a method and device for calculating the optimal temperature of an intermediate medium of a two-stage heat pump coupling heat supply system, and the method comprises the steps: taking the local outdoor heating design temperature as the low-temperature heat source temperature, and taking the average value of the supply design temperature and the backflow design temperature of the heat supply medium of a heat user side as the high-temperature heat source temperature; under the operation working condition, the outdoor environment temperature in the heating operation period serves as the low-temperature heat source temperature, and the average value of the supply operation temperature and the backflow operation temperature of a heat supply medium of the heat user side serves as the high-temperature heat source temperature; and for different working conditions, corresponding low-temperature heat source temperature and high-temperature heat source temperature are selected, and the optimal temperature of the intermediate medium of the two-stage heat pump coupling heat supply system is calculated. According to the method, a standardized intermediate medium optimal temperature calculation formula is given, so that an effective solution is provided for accurately determining the intermediate medium optimal temperature of the two-stage heat pump coupling system under different low-temperature working conditions and guaranteeing efficient and stable operation of the whole system.

Description

Technical Field

[0001] The present invention relates to the technical field of heating, and in particular to a method and device for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system. Background Art

[0002] Winter heating energy consumption is the main part of building energy consumption. Heat pump technology is used for heating of various buildings and is widely used in shopping malls, schools, stations, offices, residences and other places.

[0003] The low-temperature heat source of air source heat pump comes from the air, which is convenient and available, and has the advantages of high efficiency, no pollution, simple structure, easy installation, etc., and is widely used. However, when the heating demand increases and the ambient temperature is low, there are many problems: the heating capacity decreases, the compressor pressure ratio increases, and the exhaust temperature increases, which will trigger the automatic shutdown protection and cause frequent start and stop. At the same time, the low evaporation temperature increases the viscosity of the evaporator lubricating oil, reducing the heat exchange and lubrication performance and the isentropic efficiency of the compressor.

[0004] At present, in order to deal with the above problems, quasi-two-stage compression system, two-stage compression system, two-stage heat pump coupling system, cascade system, etc. have been proposed. Among them, the working principle of the two-stage heat pump coupling system is to use the intermediate medium as a bridge for transferring heat between the first-stage heat pump and the second-stage heat pump, and realize the transfer of heat from the low-temperature heat source to the high-temperature heat user through the series operation of the two-stage heat pump.

[0005] However, for the performance optimization of the two-stage heat pump coupling system, the existing technology rarely explores how to determine the optimal temperature of the intermediate medium. If the intermediate medium temperature deviates from the optimal value, the primary heat pump and the secondary heat pump cannot operate under the optimal working conditions, causing the entire system to consume more energy to achieve the same heating effect as when the optimal value is configured; and the non-optimal intermediate medium temperature will reduce the coefficient of performance (COP) of the heat pump system, affecting the overall operating efficiency of the system. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a method and device for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system. The optimal temperature of the intermediate medium is calculated by obtaining the corresponding low-temperature heat source temperature and high-temperature heat source temperature under test conditions and operating conditions respectively, thereby providing an effective solution for the two-stage heat pump coupled system to accurately determine the optimal temperature of the intermediate medium under different low-temperature conditions and ensure the overall efficient and stable operation of the system.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system, comprising:

[0009] In the test condition, the local outdoor heating design temperature is used as the low-temperature heat source temperature, and the average of the supply design temperature and the return design temperature of the heating medium at the heat user end is used as the high-temperature heat source temperature;

[0010] In the operating condition, the outdoor ambient temperature during the heating operation is taken as the low-temperature heat source temperature, and the average of the supply operating temperature and the return operating temperature of the heating medium at the heat user end is taken as the high-temperature heat source temperature;

[0011] For different working conditions, the corresponding low-temperature heat source temperature and high-temperature heat source temperature are selected to calculate the optimal temperature of the intermediate medium in the two-stage heat pump coupled heating system.

[0012] Preferably, the specific process of calculating the optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system is:

[0013]

[0014] Among them, t f,m is the calculated optimal temperature, t HS is the temperature of the high temperature heat source, t CS is the temperature of the low-temperature heat source; c1 = -0.0337, c2 = 4.3694, c3 = -207.24, c4 = 7809.4, c5 = 6.2468, c6 = 0.02749.

[0015] Preferably, the optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system is the design temperature or set temperature of the intermediate medium that maximizes the heating energy efficiency ratio of the two-stage heat pump coupled heating system; wherein, for test conditions it is the design temperature, and for operating conditions it is the set temperature.

[0016] Preferably, the method further includes sending a data signal of the optimal temperature of the intermediate medium to a first-stage heat pump in a two-stage heat pump coupled heating system to determine a condensing temperature setting value, and sending the data signal to a second-stage heat pump to determine an evaporating temperature setting value.

[0017] In a second aspect, the present invention provides a device for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system, comprising:

[0018] A two-stage heat pump coupled heating system includes a primary heat pump, an intermediate medium fluid circulation pump, a secondary heat pump, a user-side circulation pump and a heat user;

[0019] Working condition selection module, used to select test working condition or operation working condition;

[0020] The test condition data set storage module is used to store the local outdoor heating design temperature of multiple heating areas and the supply design temperature and return design temperature of the heating medium at different heat user ends;

[0021] The operating condition data set acquisition module is used to obtain the outdoor ambient temperature during the heating operation and the supply operating temperature and return operating temperature of the heating medium at the heat user end;

[0022] Optimal temperature calculation module: used to obtain the working condition selection instruction of the working condition selection module, and correspondingly call the test working condition data set storage module data or the operating working condition data set acquisition module data to calculate the optimal temperature of the intermediate medium.

[0023] Preferably, the working condition selection instruction of the working condition selection module is obtained, and the data of the test working condition data set storage module or the data of the operation working condition data set acquisition module are correspondingly called to calculate the optimal temperature of the intermediate medium, specifically including:

[0024] When it is a test condition, call the data in the test condition data set storage module; take the local outdoor heating design temperature as the test low-temperature heat source temperature; take the average of the supply design temperature and the return design temperature of the heat user end heating medium as the test high-temperature heat source temperature; calculate the optimal temperature of the intermediate medium under the test condition based on the test low-temperature heat source temperature and the test high-temperature heat source temperature;

[0025] When it is an operating condition, call the operating condition data set to obtain the data in the module; take the outdoor ambient temperature during the heating operation as the operating low-temperature heat source temperature; take the average value of the supply operating temperature and the return operating temperature of the heating medium at the heat user end as the operating high-temperature heat source temperature; and calculate the optimal temperature of the intermediate medium under the operating condition based on the operating low-temperature heat source temperature and the operating high-temperature heat source temperature.

[0026] Preferably, it also includes a signal sending module for sending the intermediate medium optimal temperature data signal to the primary heat pump to determine the condensing temperature setting value, and to the secondary heat pump to determine the evaporation temperature setting value.

[0027] Preferably, the primary heat pump is an air source heat pump unit, which uses R410a as the refrigerant; the secondary heat pump is a water source heat pump unit, which uses R410a as the refrigerant.

[0028] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system described in the first aspect.

[0029] In a fourth aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system described in the first aspect are implemented.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention calculates the optimal temperature of the intermediate medium by distinguishing between the test condition and the operating condition. Calculating the optimal temperature under the test condition can provide an accurate blueprint for system design. Based on the fixed outdoor design temperature and the standard temperature of the heating medium, the intermediate medium parameters can be accurately determined, which is conducive to selecting suitable equipment components and ensuring that the initial construction of the system is efficient and reasonable. Calculating the optimal temperature under the operating condition enables the system to flexibly respond to actual changes. With the weather and user heating habits, the intermediate medium temperature can be dynamically adjusted according to the real-time environment and the actual heating temperature, maintaining a high energy efficiency ratio, reducing energy consumption, improving heating stability and extending the system life.

[0032] (2) The present invention proposes a standardized formula for calculating the optimal temperature of the intermediate medium. The optimal temperature of the intermediate medium can be quickly obtained by substituting the low-temperature heat source temperature and the high-temperature heat source temperature measured under different working conditions into the formula. This improves the calculation efficiency during the design and operation process; different engineering personnel can use the same formula to calculate the two-stage heat pump coupled heating system, ensuring the consistency and reliability of the system design and operation, and is also conducive to unified evaluation and optimization of the system.

[0033] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention but do not constitute a limitation of the present invention.

[0035] Figure 1 A main flow chart of a method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system provided by an embodiment of the present invention;

[0036] Figure 2 A detailed flow chart of a method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram showing the effect of the temperature of the intermediate circulating medium on the heating COP of a two-stage heat pump coupled heating system under test conditions provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of the effect of the intermediate circulating medium temperature on the heating COP of a two-stage heat pump coupled heating system under operating conditions provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The performance and efficiency of the two-stage heat pump coupled heating system are closely related to the temperature of the low-temperature heat source and the high-temperature heat source. The temperature of the intermediate medium needs to be determined according to the temperature of the low-temperature heat source and the high-temperature heat source to ensure that the heat pump system can efficiently absorb heat from the low-temperature heat source and transfer heat to the high-temperature heat source.

[0040] The temperature of the intermediate medium needs to be reasonably selected between the evaporation temperature of the low-temperature heat source and the condensation temperature of the high-temperature heat source to ensure that the compressor and other equipment of the heat pump system can operate under appropriate working conditions. The appropriate intermediate medium temperature can improve the coefficient of performance (COP) of the heat pump, reduce system energy consumption, and improve heating efficiency. If the intermediate medium temperature is unreasonable, the heat pump system may not work properly or have low energy efficiency.

[0041] The present invention provides a standardized formula, which can accurately calculate the optimal temperature of the intermediate medium according to the low-temperature heat source temperature and the high-temperature heat source temperature under different working conditions, avoiding the errors that may be caused by empirical estimation, ensuring that the intermediate medium operates at a suitable temperature, thereby improving the energy efficiency of the two-stage heat pump coupled heating system.

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] like Figure 1 As shown, this embodiment provides a method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system, comprising the following steps:

[0044] S1: In the test condition, the local outdoor heating design temperature is used as the low-temperature heat source temperature, and the average of the supply design temperature and the return design temperature of the heating medium at the heat user end is used as the high-temperature heat source temperature;

[0045] S2: In the operating condition, the outdoor ambient temperature during the heating operation is taken as the low-temperature heat source temperature, and the average of the supply operating temperature and the return operating temperature of the heating medium at the heat user end is taken as the high-temperature heat source temperature;

[0046] S3: For different working conditions, select the corresponding low-temperature heat source temperature and high-temperature heat source temperature, and calculate the optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system.

[0047] Next, combine Figure 2 , a method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system disclosed in this embodiment is described in detail.

[0048] The intermediate circulating medium is the carrier of heat transfer between the primary heat pump and the secondary heat pump, that is, the intermediate circulating medium is the high-temperature heat source produced by the primary heat pump and the low-temperature heat source of the secondary heat pump. In order to accurately determine the optimal temperature of the intermediate circulating medium, it is necessary to first determine the low-temperature heat source temperature and the high-temperature heat source temperature.

[0049] In S1, when it is a test condition, the local outdoor heating design temperature t is obtained from the outdoor heating design temperature data set. sw , and use it as the low-temperature heat source temperature t of the two-stage heat pump coupled heating system CS ; Let t CS =t sw .

[0050] According to the terminal equipment form of the heat user, the design temperature t' of the heating medium supply is given f,d and reflow design temperature t″ f,d The design value of the heating fluid is calculated according to formula (1): The temperature t of the high temperature heat source of the two-stage heat pump coupled heating system is HS :

[0051]

[0052] It should be understood that the outdoor heating design temperature refers to the outdoor air temperature value used to calculate the heating load when designing the heating system based on the local historical meteorological conditions and relevant specifications. The outdoor heating design temperature dataset refers to a collection of data related to outdoor heating design temperatures in different regions.

[0053] Heat user terminal equipment refers to equipment that transfers the heat of the heating medium to the indoor environment, such as radiators, floor heating coils, fan coils, etc. According to different terminal equipment forms, in order to ensure its normal operation and achieve the expected heating effect, it is necessary to determine the design values ​​of the corresponding heating medium supply temperature and return temperature. These design values ​​are calculated comprehensively during the system design stage based on factors such as the needs of heat users, the characteristics of terminal equipment, and the heat load of the building.

[0054] During the design phase, the performance of the system needs to be determined based on the most unfavorable meteorological conditions, and the local outdoor heating design temperature is a representative low temperature value obtained through statistical analysis, which can ensure that the system can operate normally even in extremely cold conditions. Therefore, this embodiment selects the local outdoor heating design temperature as the test condition. Since the system is configured according to the design parameters, the average of the supply design temperature and the return design temperature of the heating medium at the heat user end is used as the high-temperature heat source temperature, which can ensure that the system achieves the expected heating effect under the design conditions and ensure the rationality and reliability of the system design.

[0055] In S2, when it is in operating condition, the temperature of the ambient medium is measured by using a temperature measuring device or a temperature measuring instrument. amb , and use it as the low-temperature heat source temperature t of the two-stage heat pump coupled heating system CS ; Let t CS =t amb .

[0056] Use temperature measuring devices or instruments to test and obtain the supply operating temperature t' of the heating medium f,o and reflux operating temperature t″ f,o The average operating temperature of the heating fluid is calculated according to formula (2). The temperature t of the high temperature heat source of the two-stage heat pump coupled heating system is HS :

[0057]

[0058] It should be understood that the environmental medium is obtained by testing with a temperature measuring device or a temperature measuring instrument, that is, the temperature of the environmental medium such as the atmosphere, water, soil, etc. is measured and monitored using various temperature sensors or temperature measuring instruments to obtain environmental temperature information.

[0059] During the actual operation of the heating system, the temperature values ​​obtained by real-time measurement of the supply temperature and return temperature of the heating medium using temperature measuring devices or instruments are the operating values ​​of the supply temperature and return temperature of the heating medium. These operating values ​​can reflect the actual operating status and heating effect of the heating system, and are an important basis for adjusting and optimizing the heating system.

[0060] This embodiment uses the outdoor ambient temperature during heating operation as the low-temperature heat source temperature, which is more in line with actual operation conditions. The outdoor ambient temperature changes in real time during operation. Using the outdoor temperature during actual operation allows the system to be adjusted according to actual conditions, thereby improving the energy efficiency and heating effect of the system operation. Using the average of the supply operating temperature and the return operating temperature of the heat user-side heating medium as the high-temperature heat source temperature can reflect the heat user-side demand of the system in actual operation, and can adjust the system according to actual needs, avoid energy waste, and improve the adaptability and stability of the system.

[0061] In S3, the optimal temperature of the intermediate medium refers to the design temperature (for test conditions) or set temperature (for operating conditions) of the intermediate circulation medium that maximizes the heating energy efficiency ratio of the two-stage heat pump coupled heating system under the conditions of constant low-temperature heat source temperature and high-temperature heat source temperature.

[0062] Formula (3) is used to calculate the optimal temperature of the intermediate medium in the two-stage heat pump coupled heating system:

[0063]

[0064] Among them, t f,m is the calculated optimal temperature, t HS is the temperature of the high temperature heat source, t CSis the temperature of the low-temperature heat source; c1 = -0.0337, c2 = 4.3694, c3 = -207.24, c4 = 7809.4, c5 = 6.2468, c6 = 0.02749.

[0065] The standardized formula proposed in this embodiment can quickly obtain the optimal temperature of the intermediate medium by simply substituting the low-temperature heat source temperature and the high-temperature heat source temperature measured under different working conditions into the formula. This greatly improves the calculation efficiency during the design and operation process, makes the operation easier, and reduces the complexity and workload of manual calculations.

[0066] As a specific implementation, after the optimal temperature of the intermediate medium is calculated, the data signal of the optimal temperature of the intermediate medium is sent to the first-stage heat pump in the two-stage heat pump coupled heating system to determine the condensing temperature setting value, and sent to the second-stage heat pump to determine the evaporation temperature setting value. Specifically:

[0067] The condensing temperature of the first stage heat pump is set as:

[0068] t 1C =t f,m +Δt CM (4)

[0069] The evaporation temperature of the two-stage heat pump is set to:

[0070] t 2E =t f,m -Δt ME (5)

[0071] Among them, t f,m is the optimal temperature of the intermediate medium; Δt CM It represents the heat exchange temperature difference between the intermediate medium and the refrigerant in the condenser of the primary heat pump, and condensers of different structural forms have their own corresponding heat exchange temperature difference value range; Δt ME It represents the heat exchange temperature difference between the intermediate medium and the refrigerant in the evaporator of the two-stage heat pump. Similarly, evaporators of different structural forms also have their own corresponding heat exchange temperature difference value range.

[0072] In order to prove the effectiveness of the solution described in this embodiment, the following relevant experimental verification is carried out in combination with specific embodiments:

[0073] Example 1

[0074] Under the test conditions, the optimal design temperature of the intermediate medium in the two-stage heat pump coupled heating system is selected and calculated.

[0075] Assuming that a residential area adopts a two-stage heat pump coupled heating system for heating in winter, and the terminal form is floor radiation heating, the calculation process of the optimal design temperature of the intermediate circulation medium of the two-stage heat pump coupled heating system is as follows:

[0076] From the outdoor heating design temperature data set, the outdoor calculated temperature of Urumqi heating is t n,s =-18.6℃, then the low temperature heat source temperature of the two-stage heat pump coupled heating system is: t CS =t n,s =-18.6℃.

[0077] Because the terminal form is floor radiation heating, the supply design temperature of the circulating fluid on the user side is t' f,h =45℃, reflux design temperature is t″ f,h =40℃, according to formula (1), the high temperature heat source temperature of the two-stage heat pump coupled heating system is:

[0078]

[0079] According to formula (3), the optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system should be:

[0080]

[0081] The following is an analysis of the calculation effect of the optimal design temperature of the intermediate medium of the two-stage heat pump coupled heating system calculated based on the algorithm of the present invention. CS =-18.6℃, t HS =42.5℃, the influence of the intermediate medium temperature on the COP (coefficient of performance) of the two-stage heat pump coupled heating system in the heating mode, such as Figure 3 As shown. Figure 3 It can be seen that when the temperature of the intermediate circulating medium is 12.62°C, the heating COP is the largest, reaching 2.6078, that is, the optimal design temperature of the intermediate medium should be 12.62°C. According to the algorithm provided by the present invention, the optimal design temperature of the intermediate circulating medium is calculated to be 12.44°C, and the relative error with the theoretical value is only -1.45%. It can be seen that the algorithm provided by the present invention is feasible for calculating the optimal design temperature of the intermediate medium of the two-stage heat pump coupled heating system. The significance of the optimal design temperature of the intermediate medium is that it can make the heating COP of the two-stage heat pump coupled heating system under the test conditions reach the optimal.

[0082] Example 2

[0083] Under the operating conditions, the optimal operating temperature of the intermediate medium in the two-stage heat pump coupled heating system is selected and calculated.

[0084] Assuming that a residential area adopts a two-stage heat pump coupled heating system for heating in winter, and the terminal form is a fan coil, the selection and calculation process of the optimal operating temperature of the intermediate circulation medium of the two-stage heat pump coupled heating system is as follows:

[0085] Use a temperature measuring device or a temperature measuring instrument to measure the outdoor ambient temperature t amb = -23.4℃, then it is used as the low temperature heat source temperature t of the two-stage heat pump coupled heating system CS =t amb =-23.4℃.

[0086] Because the terminal form is a fan coil, the supply temperature of the circulating heat medium on the user side under the test condition is generally t′ f,h =60℃, reflux temperature is t" f,h =50℃, but the supply temperature and return temperature of the heat medium on the user side change in real time with the change of the building heat load under the operating conditions. Here, it is assumed that the supply temperature of the circulating fluid on the user side is t′ f,h =60℃, reflux temperature is t" f,h =52℃, according to formula (2), the high temperature heat source temperature of the two-stage heat pump coupled heating system is:

[0087]

[0088] According to formula (3), the optimal operating temperature of the intermediate medium of the two-stage heat pump coupled heating system should be:

[0089] The following is an analysis of the calculation effect of the optimal operating temperature of the intermediate medium of the two-stage heat pump coupled heating system calculated based on the algorithm of the present invention. CS =-23.4℃, t HS =56.5℃, the influence of the intermediate medium temperature on the heating COP of the two-stage heat pump coupled heating system, such as Figure 4 As shown. Figure 4 It can be seen that when the intermediate circulating medium is 21.58°C, the heating COP is the largest, reaching 2.1184. According to the algorithm provided by the present invention, the design temperature of the intermediate circulating medium is calculated to be 20.92°C, and the relative error with the optimal design temperature of the intermediate medium is only -3.01%. It can be seen that the algorithm provided by the present invention is feasible for calculating the optimal operating temperature of the intermediate medium of the two-stage heat pump coupled heating system. The significance of the optimal operating temperature of the intermediate medium is that it can achieve the optimal heating COP of the two-stage heat pump coupled heating system during operation.

[0090] In order to solve the problem of how to accurately determine the optimal temperature of the intermediate medium in a two-stage heat pump coupling system under different low-temperature conditions, this embodiment first determines the low-temperature heat source temperature. During the test condition, the local temperature is obtained from the outdoor heating design temperature data set as the low-temperature heat source temperature. During the operating condition, the ambient medium temperature is obtained through a temperature measuring device as the low-temperature heat source temperature. Secondly, the high-temperature heat source temperature is determined. During the test condition, the average operating temperature is calculated as the high-temperature heat source temperature based on the supply and return design temperatures of the heating medium given by the heat user terminal equipment. During the operating condition, the supply and return operating temperatures of the heating medium are obtained through temperature measurement and the average operating temperature is calculated as the high-temperature heat source temperature. Finally, the optimal temperature of the intermediate medium is calculated using a formula. The optimal temperature of the intermediate medium is calculated to ensure the overall efficient and stable operation of the system.

[0091] Embodiment 2

[0092] This embodiment discloses a device for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system, comprising:

[0093] A two-stage heat pump coupled heating system includes a primary heat pump, an intermediate medium fluid circulation pump, a secondary heat pump, a user-side circulation pump and a heat user;

[0094] Working condition selection module, used to select test working condition or operation working condition;

[0095] The test condition data set storage module is used to store the local outdoor heating design temperature of multiple heating areas and the supply design temperature and return design temperature of the heating medium at different heat user ends;

[0096] The operating condition data set acquisition module is used to obtain the outdoor ambient temperature during the heating operation and the supply operating temperature and return operating temperature of the heating medium at the heat user end;

[0097] Optimal temperature calculation module: used to obtain the working condition selection instruction of the working condition selection module, and correspondingly call the test working condition data set storage module data or the operating working condition data set acquisition module data to calculate the optimal temperature of the intermediate medium.

[0098] Among them, the medium in the intermediate medium fluid circulation pump serves as a carrier for heat transfer between the primary heat pump and the secondary heat pump, that is, the intermediate circulation medium is the high-temperature heat source produced by the primary heat pump and is also the low-temperature heat source of the secondary heat pump.

[0099] It should be understood that the intermediate medium fluid circulation pump and its medium act as a bridge for heat transfer in the two-stage heat pump coupled heating system. Whether the temperature of the intermediate medium is appropriate directly affects the heat transfer efficiency between the primary heat pump and the secondary heat pump. If the temperature of the intermediate medium is too high or too low, the heat produced by the primary heat pump cannot be effectively transferred to the secondary heat pump, or the secondary heat pump cannot normally use the heat of the intermediate medium for further heating. For example, when the temperature of the intermediate medium is too low, the efficiency of the secondary heat pump in absorbing heat from the intermediate medium will decrease, and it may not be able to reach the heating temperature required by the heat user, thereby affecting the heating stability of the entire system. Therefore, the calculation of the optimal temperature of the intermediate medium is particularly important for improving the stability of the two-stage heat pump coupled heating system.

[0100] The optimal temperature of the intermediate medium refers to the temperature of the low-temperature heat source t CS and high temperature heat source temperature t HS Under certain conditions, the design temperature (for test conditions) or set temperature (for operating conditions) of the intermediate circulation medium that maximizes the heating energy efficiency ratio of the two-stage heat pump coupled heating system.

[0101] Specifically, according to different working conditions, the test working condition data set storage module data or the operating working condition data set acquisition module data are called to calculate the optimal temperature of the intermediate medium fluid circulation pump:

[0102] (1) When it is a test condition, call the data in the test condition data set storage module; use the local outdoor heating design temperature as the test low-temperature heat source temperature; use the average of the supply design temperature and the return design temperature of the heating medium at the heat user end as the test high-temperature heat source temperature; calculate the optimal temperature of the intermediate medium under the test condition based on the test low-temperature heat source temperature and the test high-temperature heat source temperature.

[0103] In this embodiment, the test condition depends on the design data and is used in the system design stage. Under the test condition, the system operates based on the design parameters, and the optimal temperature of the intermediate medium at this time is the design temperature. This temperature is determined by design calculation so that the system can achieve the best heating energy efficiency in theory.

[0104] (2) When it is an operating condition, call the data in the operating condition data set acquisition module; use the outdoor ambient temperature during the heating operation as the operating low-temperature heat source temperature; use the average value of the supply operating temperature and the return operating temperature of the heating medium at the heat user end as the operating high-temperature heat source temperature; and calculate the optimal temperature of the intermediate medium under the operating condition based on the operating low-temperature heat source temperature and the operating high-temperature heat source temperature.

[0105] In this embodiment, the operating conditions rely on measured data and are used to adjust parameters during the actual operation of the system. Under the operating conditions, the actual operating environment of the system may be different from the design. The heating energy efficiency is optimized by adjusting the set temperature of the intermediate medium to achieve the best in actual operation.

[0106] Furthermore, the calculation process of the optimal temperature of the intermediate medium fluid circulation pump is specifically as follows:

[0107]

[0108] Among them, t HS To test the high temperature heat source temperature or operate the high temperature heat source temperature; t CS To test the low-temperature heat source temperature or run the low-temperature heat source temperature; c1 = -0.0337, c2 = 4.3694, c3 = -207.24, c4 = 7809.4, c5 = 6.2468, c6 = 0.02749.

[0109] Through the above formula, as well as the low-temperature heat source temperature and high-temperature heat source temperature obtained under different working conditions, the optimal temperature of the intermediate medium can be solved.

[0110] As a specific implementation, it also includes a signal sending module for sending the intermediate medium optimal temperature data signal to the primary heat pump to determine the condensing temperature setting value, and to the secondary heat pump to determine the evaporation temperature setting value.

[0111] As a specific implementation method, the primary heat pump is an air source heat pump unit, which uses R410a as a refrigerant, and the condensing temperature of the primary heat pump is set to t 1C =t f,m +Δt CE The secondary heat pump uses a water source heat pump unit, which uses R410a as the refrigerant. The evaporation temperature of the secondary heat pump is set to t 1C =t f,m -Δt CE .

[0112] As a specific implementation method, the two-stage heat pump coupled heating system also includes other auxiliary equipment and devices, including constant pressure equipment, water replenishment equipment, temperature measuring devices, pressure measuring devices, valves and other common auxiliary equipment and devices in the heating system, which are used to ensure the stable, safe and accurate operation of the two-stage heat pump coupled heating system and facilitate the corresponding parameter monitoring and adjustment; the specific type and quantity of equipment used are not limited in this embodiment.

[0113] When determining the temperature of the low-temperature heat source, this embodiment distinguishes between the test condition and the operating condition to obtain data, so that the temperature determination is more accurate and can better adapt to the actual situation. For the determination of the temperature of the high-temperature heat source, whether it is based on the design value or the measured value, there is a scientific calculation method to ensure the reliability of the temperature of the high-temperature heat source. Calculating the optimal temperature of the intermediate medium through the formula helps to optimize the operation of the two-stage heat pump coupled heating system. This can not only improve the energy utilization efficiency of the system and reduce energy waste, but also reduce the operating cost and maintenance cost of the system to a certain extent.

[0114] Embodiment 3

[0115] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps in the method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system as described in the first embodiment above are implemented.

[0116] Embodiment 4

[0117] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system as described in the first embodiment above are implemented.

[0118] The steps or modules involved in the above embodiments 2 to 4 correspond to those in embodiment 1. For the specific implementation, please refer to the relevant description of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system, characterized in that: include: In the test condition, the local outdoor heating design temperature is used as the low-temperature heat source temperature, and the average of the supply design temperature and the return design temperature of the heating medium at the heat user end is used as the high-temperature heat source temperature; In the operating condition, the outdoor ambient temperature during the heating operation is taken as the low-temperature heat source temperature, and the average of the supply operating temperature and the return operating temperature of the heating medium at the heat user end is taken as the high-temperature heat source temperature; For different working conditions, the corresponding low-temperature heat source temperature and high-temperature heat source temperature are selected to calculate the optimal temperature of the intermediate medium in the two-stage heat pump coupled heating system.

2. A method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 1, characterized in that: The specific process of calculating the optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system is as follows: Among them, t f,m is the calculated optimal temperature, t HS is the temperature of the high temperature heat source, t CS is the temperature of the low-temperature heat source; c1 = -0.0337, c2 = 4.3694, c3 = -207.24, c4 = 7809.4, c5 = 6.2468, c6 = 0.02749.

3. A method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 1, characterized in that: The optimal temperature of the intermediate medium of the two-stage heat pump coupled heating system is the design temperature or set temperature of the intermediate medium that maximizes the heating energy efficiency ratio of the two-stage heat pump coupled heating system; wherein, for the test condition it is the design temperature, and for the operating condition it is the set temperature.

4. A method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 1, characterized in that: The method also includes sending a data signal of the optimal temperature of the intermediate medium to a first-stage heat pump in a two-stage heat pump coupled heating system to determine a condensing temperature setting value, and sending the data signal to a second-stage heat pump to determine an evaporation temperature setting value.

5. A device for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system, characterized in that: include: A two-stage heat pump coupled heating system includes a primary heat pump, an intermediate medium fluid circulation pump, a secondary heat pump, a user-side circulation pump and a heat user; Working condition selection module, used to select test working condition or operation working condition; The test condition data set storage module is used to store the local outdoor heating design temperature of multiple heating areas and the supply design temperature and return design temperature of the heating medium at different heat user ends; The operating condition data set acquisition module is used to obtain the outdoor ambient temperature during the heating operation and the supply operating temperature and return operating temperature of the heating medium at the heat user end; Optimal temperature calculation module: used to obtain the working condition selection instruction of the working condition selection module, and correspondingly call the test working condition data set storage module data or the operating working condition data set acquisition module data to calculate the optimal temperature of the intermediate medium.

6. The device for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 5, characterized in that: The working condition selection instruction of the working condition selection module is obtained, and the data of the test working condition data set storage module or the data of the operation working condition data set acquisition module are correspondingly called to calculate the optimal temperature of the intermediate medium, specifically including: When it is a test condition, call the data in the test condition data set storage module; take the local outdoor heating design temperature as the test low-temperature heat source temperature; take the average of the supply design temperature and the return design temperature of the heat user end heating medium as the test high-temperature heat source temperature; calculate the optimal temperature of the intermediate medium under the test condition based on the test low-temperature heat source temperature and the test high-temperature heat source temperature; When it is an operating condition, call the operating condition data set to obtain the data in the module; take the outdoor ambient temperature during the heating operation as the operating low-temperature heat source temperature; take the average value of the supply operating temperature and the return operating temperature of the heating medium at the heat user end as the operating high-temperature heat source temperature; and calculate the optimal temperature of the intermediate medium under the operating condition based on the operating low-temperature heat source temperature and the operating high-temperature heat source temperature.

7. The device for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 5, characterized in that: It also includes a signal sending module for sending the intermediate medium optimal temperature data signal to the first-level heat pump to determine the condensing temperature setting value, and to the second-level heat pump to determine the evaporation temperature setting value.

8. The device for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system according to claim 5, characterized in that: The primary heat pump is an air source heat pump unit, which uses R410a as the refrigerant; the secondary heat pump is a water source heat pump unit, which uses R410a as the refrigerant.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for calculating the optimal temperature of an intermediate medium in a two-stage heat pump coupled heating system as described in any one of claims 1 to 4 are implemented.

10. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps in the method for calculating the optimal temperature of the intermediate medium in a two-stage heat pump coupled heating system as described in any one of claims 1 to 4 are implemented.

Images