Operation control method and electronic equipment based on air source heat pump load rate optimization

Abstract

The present invention relates to the field of control methods, and particularly to an operation control method and an electronic device based on the optimization of the load rate of an air source heat pump. The control method includes: calculating and determining whether the load rate Li of the heat pump unit obtained is ≤ 1; calculating the energy efficiency COP of the unit without frosting Li ; determining whether the evaporation temperature Tei satisfies Tei < Td and Tei < 0; calculating the defrost correction coefficient Fi, Fi = (Qi – Qd) / Wi / COP Li ; calculating and recording the comprehensive energy efficiency COPci of the heat pump unit, COPci = COP Li *Fi; determining whether i is equal to the maximum number of units n of the unit, and selecting the maximum value from the multiple COPcis calculated through program circulation to determine the optimal number of units to be started for the system. By performing cyclic iteration on the number of units to be started, calculating the load rate of the unit and the influence of frosting on energy efficiency under different numbers of units to be started, a more accurate comprehensive energy efficiency calculation result can be obtained. By comparing the highest value of the comprehensive energy efficiency of the unit under different numbers of units to be started, the optimal number of units to be started is determined, which can significantly improve the comprehensive energy efficiency of the unit, thereby achieving the purpose of energy conservation.

Description

Technical Field

[0001] The present invention relates to the field of control methods, and in particular to an operation control method and electronic equipment based on air source heat pump load rate optimization. Background Art

[0002] like Figure 1 As shown in the figure, the COP of the air source heat pump unit changes with the load rate of the unit. Under the same environmental conditions and outlet water temperature conditions, the energy efficiency of a certain fixed-frequency air source heat pump unit is highest under full load conditions. Therefore, the operating strategy of most air source heat pump heating projects is to reduce the number of units turned on as the load decreases, and keep the unit running at a high load rate as much as possible. However, these performance coefficients are all tested under non-frosting conditions. Frosting will cause the unit's energy efficiency to decline significantly, and in severe cases it may decline to 20%~30%. Therefore, the actual operating system energy efficiency is relatively low. For variable frequency units, the unit's highest energy efficiency point is not even under full load conditions, but in the range of 40%~80%.

[0003] For a specific building heating load, as the number of air-source heat pumps operating increases, the load factor of each unit decreases, and the fin heat exchanger area of ​​the air-source heat pump unit is fully utilized, thereby increasing the unit's evaporation temperature. In frosting conditions, the higher the unit's evaporation temperature, the slower the frosting rate, or even no frosting, thereby achieving higher overall energy efficiency for the unit.

[0004] Therefore, the present invention aims to propose an optimization control method to determine the optimal load rate of the unit under various operating conditions, and ultimately achieve the highest comprehensive energy efficiency operation strategy through unit number control, providing guidance for the operation of air source heat pump projects. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an operation control method and electronic device based on air source heat pump load rate optimization, to perform optimal calculation on a heating project with multiple air source heat pump units, and to calculate the load rate of the unit and the impact of frosting on energy efficiency under different numbers of units turned on by cyclic iteration, so as to obtain a more accurate comprehensive energy efficiency calculation result, and to determine the optimal number of units turned on by comparing the maximum value of the comprehensive energy efficiency of the unit under different numbers of units turned on, thereby achieving the purpose of energy saving.

[0006] In a first aspect, the present invention provides an operation control method based on air source heat pump load rate optimization, comprising the following steps:

[0007] S1: Input the number of units n, ambient dry bulb temperature Ta, ambient relative humidity RH, and unit outlet water temperature Tw, and calculate the air dew point temperature Td based on the ambient dry bulb temperature Ta and ambient relative humidity RH;

[0008] S2: Set the number of air source heat pump units started \(i = 1\), and calculate the load rate \(L_i\) of the heat pump unit when 1 unit is started;

[0009] S3: Determine whether the calculated load rate \(L_i\) of the heat pump unit is \(\leq1\). If so, go to step S4; if not, change the number of started heat pump units \(i\) to \(i + 1\), and recalculate the load rate \(L_i\) of the heat pump unit;

[0010] S4: Input the three - dimensional curve atlas of the evaporation temperature of the unit varying with the load rate, ambient dry - bulb temperature \(T_a\), and ambient relative humidity \(RH\). Query the evaporation temperature \(T_{ei}\) and heating power \(q\) , , , , , , Li ,

[0017] ,

[0016] ,

[0015] ,

[0014] ,

[0018] ,

[0013] 、power consumption \(p\) Li of the heat pump unit without frosting under the current working conditions, and calculate the energy efficiency COP of the unit without frosting Li ;

[0011] S5: Determine whether the evaporation temperature \(T_{ei}\) satisfies \(T_{ei}<T_d\) and \(T_{ei}<0\). If so, go to step S6; if not, the defrost correction factor \(F_i = 1.0\), and directly go to step S7;

[0012] S6: Calculate the defrost correction factor \(F_i\), \(F_i=[(Q_i–Q_d) / W_i] / COP\) Li , where \(Q_i\) is the cumulative cycle heating capacity of the unit under the defrost working condition, \(Q_d\) is the defrost heat consumption of the unit under the defrost working condition, and \(W_i\) is the cumulative cycle power consumption of the unit under the defrost working condition;

[0013] S7: Calculate and record the comprehensive energy efficiency \(COP_{ci}\) of the heat pump unit, \(COP_{ci}=COP\) Li *\(F_i\);

[0014] S8: Determine whether \(i\) is equal to the maximum number of units \(n\) of the unit. If not, change the number of started heat pump units \(i\) to \(i + 1\), and return to the step of calculating the load rate \(L_i\) of the heat pump unit for cyclic calculation. If so, select the maximum value from the multiple \(COP_{ci}\) obtained by cyclic calculation according to the program, so as to determine the optimal number of started units of the system.

[0015] Preferably, in steps S2 and S3, the calculation method of the load rate \(L_i\) of the heat pump unit is:

[0016] Monitor the supply water temperature \(T_s\), return water temperature \(T_r\) of the building heating main pipe, and the main pipe flow rate \(M\);

[0017] Calculate the building load \(L_b\): \(L_b = CM(T_s - T_r)\), where \(C\) is the specific heat capacity of water;

[0018] Calculate the heating capacity \(q\) of a single heat pump unit running at full load under the working conditions of the ambient dry - bulb temperature \(T_a\), ambient relative humidity \(RH\), and the outlet water temperature \(T_w\) of the unit;

[0019] Calculate the load rate Li of the heat pump unit: Li=[Lb / i] / q.

[0020] Preferably, in step S4, the energy efficiency COP of the unit during frost-free period is Li The calculation formula is: COP Li =q Li / p Li。

[0021] Preferably, in step S6, the defrost correction coefficient Fi is calculated as follows:

[0022] Input the defrost cycle duration of the unit and the three-dimensional curve of the random group evaporation temperature, ambient dry bulb temperature Ta, and ambient relative humidity RH;

[0023] Query the defrost cycle duration τ of the unit under the current working conditions i ;

[0024] According to the obtained defrost cycle time τ i , under the defrosting condition of the computer group, the cycle cumulative heating amount Qi, the defrosting heat consumption Qd and the cycle cumulative power consumption Wi;

[0025] Calculate the defrost correction factor Fi, Fi = [(Qi - Qd) / Wi] / COP Li .

[0026] In a second aspect, the present invention provides an electronic device comprising a processor, a network interface and a memory, wherein the processor, the network interface and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute any one of the control methods described.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention performs optimization calculation on projects that use multiple air source heat pump units for heating. By iterating the number of units turned on, the impact of frosting on the energy efficiency of the units under different numbers of units turned on is calculated, thereby obtaining a more accurate comprehensive energy efficiency calculation result.

[0029] By comparing the maximum comprehensive energy efficiency of the unit under different numbers of units turned on, and thus determining the optimal number of units turned on, the beneficial result of significantly improving the comprehensive energy efficiency of the unit can be achieved, thereby achieving the goal of energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the energy efficiency COP of the air source heat pump unit described in the background technology.

[0031] Figure 2 Schematic diagram of the control method of the present invention.

[0032] Figure 3 Schematic diagram of a method for calculating the load rate Li of the heat pump unit according to the present invention.

[0033] Figure 4 Schematic diagram of the calculation method of the defrost correction coefficient Fi according to the present invention.

[0034] Figure 5 This is a schematic diagram of the comprehensive energy efficiency of the unit calculated according to Example 2 of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0036] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating orientation or positional relationships such as "upper," "lower," "left," "right," "center," "inside," and "outside" are based on the orientation or positional relationships shown in the accompanying drawings, or are the orientation or positional relationships in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationships are merely for the purpose of facilitating the description of the present invention or simplifying the description of the specific embodiments to facilitate a quick understanding of the solutions by technicians, and do not indicate or imply that a particular device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0037] In addition, the use of terms such as "horizontal," "vertical," "overhanging," "parallel," and "coaxial" does not necessarily require that the corresponding devices / components / elements be absolutely horizontal, vertical, overhanging, parallel, or coaxial. Instead, they may be slightly tilted or have deviations, as long as they do not affect the normal function of the relevant components. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted. "Coaxial" means that the two components are arranged as coaxially as possible, so that they move in a coaxial or approximately coaxial manner when their relative positions change. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are arranged in a "horizontal," "vertical," "overhanging," "parallel," or "coaxial" direction, and can have an error / deviation of ±10% relative to the corresponding direction, more preferably within an error / deviation of ±8%, more preferably within an error / deviation of ±6%, more preferably within an error / deviation of ±5%, and more preferably within an error / deviation of ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the solution of the present invention.

[0038] In addition, the expressions “first”, “second”, “third”, etc. in the terms are merely used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of specific components.

[0039] In addition, in the description of the embodiments of the present invention, "several," "a plurality," and "a number" represent at least two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0040] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0041] Example 1

[0042] like Figure 2 As shown, an operation control method based on air source heat pump load rate optimization for air source heat pump engineering projects includes the following steps:

[0043] S1: Input the number of units n, ambient dry-bulb temperature Ta, ambient relative humidity RH, and unit outlet water temperature Tw. Calculate the air dew point temperature Td based on the ambient dry-bulb temperature Ta and ambient relative humidity RH. The program then enters a cyclic calculation process, setting the number of air source heat pump units i to be activated, and performing a cyclic calculation from 1 to n.

[0044] S2: Set the number of air source heat pump units turned on i=1, and calculate the load rate Li of the heat pump unit when one unit is turned on;

[0045] like Figure 3 As shown in Figure 2, the calculation method of the heat pump unit load rate Li is:

[0046] Monitor the building heating main water supply temperature Ts, main return water temperature Tr and main flow M;

[0047] Calculate the building load Lb: Lb = CM (Ts - Tr), where: C is the specific heat capacity of water;

[0048] Calculate the heating capacity q of a single heat pump unit operating at full load under the operating conditions of ambient dry-bulb temperature Ta, ambient relative humidity RH, and unit outlet water temperature Tw;

[0049] Calculate the load rate Li of the heat pump unit: Li=[Lb / i] / q.

[0050] S3: Determine whether the calculated heat pump unit load factor Li is ≤ 1. If so, proceed to step S4. If not, the number of active heat pump units, i, is increased to i+1, and the heat pump unit load factor Li is recalculated. Since the load factor Li normally ranges from 0 to 1, if it is greater than 1, it indicates that the total heat supply of the heat pump units, i, is insufficient to meet the building's heat load. Therefore, an additional unit is activated, increasing the number of active units, i, to i+1, and the heat pump unit load factor, Li, is recalculated until the newly calculated Li meets the requirements.

[0051] S4: Input the three-dimensional curve of the unit evaporation temperature along with the unit load rate, ambient dry bulb temperature Ta, and ambient relative humidity RH, and query the evaporation temperature Tei and heating power q of the heat pump unit under frost-free operation under this working condition. Li , power consumption p Li , and calculate the energy efficiency COP of the unit during frost-free period Li , COP Li =q Li / p Li .

[0052] S5: Determine whether the evaporation temperature Tei satisfies Tei < Td and Tei < 0. If so, proceed to step S6; if not, the defrost correction factor Fi = 1.0 and directly proceed to step S7. If the evaporation temperature Tei meets the requirements, it proves that the unit will frost. Therefore, the comprehensive energy efficiency of the unit needs to consider the attenuation effect of frosting and defrosting on energy efficiency. Quantify its impact in the form of the defrost correction factor Fi. The calculation method of the defrost correction factor Fi is as Figure 4 shown.

[0053] S6: As Figure 4 shown, input the three-dimensional curve atlas of the defrost cycle duration of the unit with respect to the three parameters of the unit's evaporation temperature, ambient dry bulb temperature Ta, and ambient relative humidity RH;

[0054] Query the defrost cycle duration τ of the unit under this operating condition i ;

[0055] According to the obtained defrost cycle duration τ i , calculate the cycle cumulative heating capacity Qi, defrost heat consumption Qd, and cycle cumulative power consumption Wi of the unit under the defrost operating condition;

[0056] Calculate the defrost correction factor Fi, Fi = [(Qi – Qd) / Wi] / COP Li .

[0057] S7: Calculate and record the comprehensive energy efficiency COPci of the heat pump unit, COPci = COP Li *Fi.

[0058] S8: Determine whether i is equal to the maximum number of units n of the unit. If not, the number of operating heat pump units i becomes i + 1, and return to the step of calculating the load rate Li of the heat pump unit for cyclic calculation. If so, select the maximum value from the multiple COPci obtained through cyclic calculation according to the program, so as to determine the optimal number of operating units of the system.

[0059] Example 2

[0060] On the basis of Example 1, take a certain actual office project as an example. The project uses 8 air-cooled screw heat pump units with the same capacity to heat the building, and the heating capacity of the unit under rated conditions is 700 kW.

[0061] First step: Determine the input conditions: n = 8, ambient dry bulb temperature Ta = 5°C, ambient relative humidity RH = 80%, unit outlet water temperature Tw = 45°C, and calculate the air dew point temperature Td = 1.84°C;

[0062] Second step: Start cyclic calculation, taking i = 1 as an example. Monitor the supply water temperature Ts = 45°C, return water temperature Tr = 40°C of the building heating main pipe, and the main pipe flow rate M = 400 m³ / h;

[0063] Step 3: Calculate the building load Lb = CM(Ts - Tr) = 2333 kW;

[0064] Step 4: According to the performance curve of the unit sample, calculate the heating capacity q = 658 kW when the heat pump unit operates at full load under the conditions of ambient dry-bulb temperature Ta = 5°C, ambient relative humidity RH = 80%, and unit outlet water temperature Tw = 45°C;

[0065] Step 5: Calculate and obtain L1 = Lb / 1 / q = 3.54;

[0066] Step 6: Judge and find that L1 ≥ 1, let i = 2, and re-loop the above steps for calculation. After calculation, it is found that until i = 4, after judgment, it is found that L4 = 0.89 ≤ 1;

[0067] Step 7: Input the three-dimensional curve atlas of the unit evaporation temperature Tei with respect to the three parameters of unit load ratio, ambient dry-bulb temperature Ta, and ambient relative humidity RH, and query the evaporation temperature Te4 = -5°C of the heat pump unit under this condition;

[0068] Step 8: Query that the unit load ratio of the unit under this condition is 89%, and the heating power qL4 = 615 kW, power consumption pL4 = 187 kW, and COP = 3.29 for frost-free operation of the unit;

[0069] Step 9: Judge that Te4 = -5°C < 0, and Te4 < Td, so the unit is in the frosting condition;

[0070] Step 10: Calculate the defrost correction coefficient F4, and input the three-dimensional curve atlas of the unit defrost cycle duration with respect to the three parameters of unit evaporation temperature, ambient dry-bulb temperature Ta, and ambient relative humidity RH;

[0071] Step 11: Query that the defrost cycle duration τ4 = 40 min of the unit under this condition. Calculate that under the defrost condition of the unit, the cumulative heat generation Q4 = 268 kWh, defrost heat consumption Qd = 55 kWh, and cumulative power consumption W4 = 125 kWh during the cycle;

[0072] Step 12: Calculate and obtain the defrost correction coefficient F4 = 0.65; [[ID=3]]

[0073] Step 13: Calculate cyclically to obtain the comprehensive energy efficiency COPc4 = 2.15, COPc5 = 2.17, COPc6 = 2.21, COPc7 = 2.17, COPc8 = 2.12;

[0074] Step 14: According to the calculation results as Figure 5 shown, by comparison, when the COPc is at its maximum value, the value of i is 6, and set the number of units started n = 6.

[0075] As can be seen from this embodiment, for a project using multiple air source heat pump units, when the building load is not at full load, the above optimization control method can achieve the beneficial result of significantly improving the comprehensive energy efficiency of the units.

[0076] Example 3

[0077] An electronic device includes a processor, a network interface and a memory, wherein the processor, the network interface and the memory are interconnected, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the control method described in Example 1.

[0078] A computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the control method as described in Example 1.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An operation control method based on air source heat pump load rate optimization, characterized in that: It includes the following steps: S1: Input the number of units n, the ambient dry-bulb temperature Ta, the ambient relative humidity RH, the water outlet temperature Tw of the unit, and calculate the air dew-point temperature Td based on the ambient dry-bulb temperature Ta and the ambient relative humidity RH; S2: Set the number of air-source heat pump units turned on i = 1, and calculate the load rate Li of the heat pump unit in the case of turning on 1 unit; S3: Judge whether the calculated load rate Li of the heat pump unit is ≤ 1. If so, enter step S4. If not, change the number of heat pump units turned on i to i + 1, and recalculate the load rate Li of the heat pump unit; S4: Input the three-dimensional curve of the unit evaporation temperature and the load rate, ambient dry bulb temperature Ta, and ambient relative humidity RH, and query the evaporation temperature Tei and heating power q of the heat pump unit under the current working conditions. Li , power consumption p Li , and calculate the energy efficiency COP of the unit during frost-free period Li ; S5: Judge whether the evaporation temperature Tei satisfies Tei < Td and Tei < 0. If so, enter step S6. If not, the defrost correction factor Fi = 1.0, and directly enter step S7; S6: Calculate the defrost correction factor Fi, Fi = [(Qi–Qd) / Wi] / COP Li , Qi is the cumulative heating capacity of the unit under defrosting conditions, Qd is the heat consumed by defrosting under defrosting conditions, and Wi is the cumulative power consumption of the unit under defrosting conditions; S7: Calculate and record the comprehensive energy efficiency COPci of the heat pump unit, COPci = COP Li *Fi; S8: Judge whether i is equal to the maximum number of units n. If not, change the number of heat pump units turned on i to i + 1, and return to the step of calculating the load rate Li of the heat pump unit for cyclic calculation. If so, select the maximum value from the multiple COPcis obtained by cyclic calculation according to the program, so as to determine the optimal number of units turned on in the system.

2. The operation control method based on air source heat pump load rate optimization according to claim 1 is characterized in that: In steps S2 and S3, the calculation method of the load rate Li of the heat pump unit is as follows: Monitor the supply water temperature Ts, the return water temperature Tr of the building heating main pipe, and the main pipe flow rate M; Calculate the building load Lb: Lb = CM(Ts - Tr), where: C is the specific heat capacity of water; Calculate the heating capacity q of a single heat pump unit under full load operation under the conditions of the ambient dry-bulb temperature Ta, the ambient relative humidity RH, and the water outlet temperature Tw of the unit; Calculate the load rate Li of the heat pump unit: Li = [Lb / i] / q.

3. The operation control method based on air source heat pump load rate optimization according to claim 1 is characterized in that: In step S4, the energy efficiency COP of the unit during frost-free period is Li The calculation formula is: COP Li =q Li / p Li。 4. The operation control method based on air source heat pump load rate optimization according to claim 1, characterized in that: In step S6, the calculation method of the defrost correction factor Fi is as follows: Input the three-dimensional curve atlas of the defrost cycle duration of the unit varying with three parameters, namely the evaporation temperature, the ambient dry-bulb temperature Ta, and the ambient relative humidity RH; Query the defrost cycle duration τ of the unit under the current working conditions i ; According to the obtained defrost cycle time τ i , under the defrosting condition of the computer group, the cycle cumulative heating amount Qi, the defrosting heat consumption Qd and the cycle cumulative power consumption Wi; Calculate the defrost correction factor Fi, Fi = [(Qi - Qd) / Wi] / COP Li .

5. An electronic device, characterized in that: It includes a processor, a network interface, and a memory, and the processor, the network interface, and the memory are interconnected. Among them, the memory is used to store a computer program, the computer program includes program instructions, and the processor is configured to call the program instructions to execute the control method according to any one of claims 1-4.

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