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

Abstract

The invention relates to the field of control methods, in particular to an operation control method and electronic equipment based on air source heat pump load rate optimization, and the control method comprises the following steps: calculating and judging whether the obtained heat pump unit load rate Li is less than or equal to 1; the unit energy efficiency COPLi in the frostless state is calculated; whether the evaporation temperature Tei meets the Tilt or not is judged; td, Tilt, Td, Tilt; 0; calculating a defrosting correction coefficient Fi, wherein Fi = (Qi-Qd) / Wi / COPLi; calculating and recording the comprehensive energy efficiency COPci of the heat pump unit, wherein COPci = COPLi * Fi; whether i is equal to the maximum number n of the units is judged, the maximum value is selected according to the multiple COPci obtained through program loop calculation, and therefore the optimal starting number of the system is determined. The number of started units is subjected to loop iteration, and the influence of unit load rates and frosting on energy efficiency under the condition of different numbers of started units is calculated, so that a more accurate comprehensive energy efficiency calculation result is obtained. The optimal number of started units is determined by comparing the maximum values of the comprehensive energy efficiency of the units under the condition of different numbers of started units, so that the comprehensive energy efficiency of the units can be remarkably improved, and the purpose of saving energy is achieved.

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: 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; S2: Set the number of air source heat pump units in operation \(i = 1\), and calculate the load factor \(L_i\) of the heat pump unit when 1 unit is in operation; S3: Determine whether the calculated load factor \(L_i\) of the heat pump unit is \(\leq1\). If so, proceed to step S4. If not, change the number of heat pump units in operation \(i\) to \(i + 1\), and recalculate the load factor \(L_i\) of the heat pump unit; S4: Input the three-dimensional curve atlas of the evaporation temperature \(T_e\) of the unit varying with the three parameters of the load factor \(L\) of the unit, the ambient dry bulb temperature \(T_a\), and the ambient relative humidity \(RH\), and query the evaporation temperature \(T_{ei}\) and heating power \(q\) of the heat pump unit for frost-free operation under the current working conditions Li , power consumption \(p\) Li , and calculate the energy efficiency COP of the unit during frost-free operation Li ; S5: Determine whether the evaporation temperature \(T_{ei}\) satisfies \(T_{ei}<T_d\) and \(T_{ei}<0\). If so, proceed to step S6. If not, the defrost correction factor \(F_i = 1.0\), and directly proceed to step S7; S6: Calculate the defrost correction factor \(F_i\), \(F_i=(Q_i - Q_d) / W_i / COP\) Li , where \(Q_i\) is the cumulative heat output during the defrost cycle of the unit, \(Q_d\) is the heat consumption during defrost of the unit, and \(W_i\) is the cumulative power consumption during the defrost cycle of the unit; S7: Calculate and record the comprehensive energy efficiency \(COP_{ci}\) of the heat pump unit, \(COP_{ci}=COP\) Li * \(F_i\); S8: Determine whether \(i\) is equal to the maximum number of units \(n\) of the unit. If not, change the number of heat pump units in operation \(i\) to \(i + 1\), and return to the step of calculating the load factor \(L_i\) of the heat pump unit for cyclic calculation. If so, select the maximum value from the multiple \(COP_{ci}\) obtained through cyclic calculation according to the program, so as to determine the optimal number of units in operation of the system.

[0007] Preferably, in steps S2 and S3, the calculation method of the load factor \(L_i\) of the heat pump unit is as follows: Monitor the supply water temperature \(T_s\), return water temperature \(T_r\) of the building heating main pipe, and the main pipe flow rate \(M\); Calculate the building load \(L_b\): \(L_b = CM(T_s - T_r)\), 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 working conditions of the ambient dry bulb temperature \(T_a\), ambient relative humidity \(RH\), and the outlet water temperature \(T_w\) of the unit; Calculate the load factor \(L_i\) of the heat pump unit: \(L_i = L_b / i / q\).

[0008] Preferably, in step S4, the formula for calculating the energy efficiency COP of the unit during frost-free operation Li is: COP Li =q Li / pLi。

[0009] Preferably, in step S6, the calculation method of the defrost correction coefficient Fi is as follows: Input the three-dimensional curve atlas of the defrost cycle duration τ of the unit varying with three parameters: the evaporation temperature Te of the unit, 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 condition i ; According to the obtained defrost cycle duration τ i , calculate the cumulative heat output Qi, the defrost heat consumption Qd, and the cumulative power consumption Wi during the cycle under the defrost working condition of the unit; Calculate the defrost correction coefficient Fi, Fi = (Qi - Qd) / Wi / COPLi.

[0010] In a second aspect, the present invention provides an electronic device, including a processor, a network interface, and a memory. 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 any one of the control methods.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention performs optimization calculations on projects using multiple air source heat pump units for heating. By performing cyclic iteration on the number of operating units, it calculates the impact of frosting of the units on energy efficiency under different numbers of operating units, so as to obtain a more accurate comprehensive energy efficiency calculation result.

[0012] By comparing the maximum values of the comprehensive energy efficiency of the units under different numbers of operating units, the optimal number of operating units is determined, which can achieve the beneficial result of significantly improving the comprehensive energy efficiency of the units, thereby achieving the purpose of energy conservation. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the energy efficiency COP of the air source heat pump unit described in the background technology.

[0014] Figure 2 It is a schematic flowchart of the control method described in the present invention.

[0015] Figure 3 It is a schematic diagram of the calculation method of the load factor Li of the heat pump unit described in the present invention.

[0016] Figure 4 It is a schematic diagram of the calculation method of the defrost correction coefficient Fi described in the present invention.

[0017] Figure 5Schematic diagram of the comprehensive energy efficiency of the unit calculated in Embodiment 2 of the present invention. Specific embodiments

[0018] The present invention will be further described in detail below in conjunction with specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. Any technology implemented based on the content of the present invention belongs to the scope of the present invention.

[0019] In the description of the specific embodiments of the present invention, unless otherwise specified, the expression terms indicating the orientation or positional relationship such as "upper", "lower", "left", "right", "center", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the invention product / device / device is normally used. These orientation or positional relationship terms are only for the convenience of describing the present invention solution or simplifying the description in specific embodiments, facilitating technicians to quickly understand the solution, rather than indicating or implying that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, it should not be construed as a limitation to the present invention.

[0020] In addition, if terms such as "horizontal", "vertical", "hanging", "parallel", "coaxial" appear, it does not mean that the corresponding device / component / element is required to be absolutely horizontal or vertical or hanging or parallel or coaxial, but can be slightly inclined or have a deviation, as long as the normal functions of the relevant components are not affected. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined; "coaxial" means that two components are arranged as coaxial as possible, and when the relative position changes, they move in a coaxial or approximately coaxial manner. Or, it can be simply understood that the corresponding device / component / element is arranged in directions such as "horizontal", "vertical", "hanging", "parallel", "coaxial", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2 - 1 mm, preferably within 0.2 - 0.5 mm. As long as the corresponding device / component / element is within the error / deviation range, it can still play its role in the solution of the present invention.

[0021] In addition, the expressions such as "first", "second", "third", etc. in the terms are only used to distinguish the description of the same or similar components, and should not be construed as emphasizing or implying the relative importance of specific components.

[0022] In addition, in the description of the embodiments of the present invention, "several", "multiple", and "a number of" represent at least two. It can be any situation such as 2, 3, 4, 5, 6, 7, 8, 9, etc., and even can be a situation exceeding 9.

[0023] In addition, in the description of the technical solutions of the present invention, unless otherwise clearly specified / defined / restricted, where the terms "set", "installed", "connected", "linked", "provided with", "laid", "arranged" appear, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be connection means commonly used in the art such as welding, riveting, bolting, and threaded connection. Such a connection can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components.

[0024] Embodiment 1 As Figure 2 shown, an operation control method based on the optimization of the load rate of an air-source heat pump for an air-source heat pump engineering project includes the following steps: S1: Input the number of units n, the ambient dry-bulb temperature Ta, the ambient relative humidity RH, and the water outlet temperature Tw of the unit, and calculate the air dew point temperature Td according to the ambient dry-bulb temperature Ta and the ambient relative humidity RH. Then the program enters the loop calculation process, and set the number of air-source heat pump units i to loop and calculate one by one from 1 to n.

[0025] S2: Set the number of air-source heat pump units i = 1, and calculate the load rate Li of the heat pump unit when 1 unit is turned on; As Figure 3 shown, the calculation method of the load rate Li of the heat pump unit is: Monitor the supply water temperature Ts, the return water temperature Tr, and the total flow rate M of the building heating main pipe; Calculate the building load Lb: Lb = CM(Ts - Tr), where: C is the specific heat capacity of water; Calculate the full-load heating capacity q of a single heat pump unit 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.

[0026] S3: Determine whether the calculated load rate Li of the heat pump unit is ≤ 1. If so, proceed to step S4. If not, the number of operating units i becomes i + 1, and recalculate the load rate Li of the heat pump unit. Since the normal range of the load rate Li is between 0 and 1, if the situation of > 1 occurs, it means that when the number of operating units is i, the total heat supply of the heat pump unit is difficult to meet the building heating load. Therefore, an additional unit needs to be started, that is, the number of operating units i becomes i + 1, and recalculate the load rate Li of the heat pump unit until the newly calculated Li meets the requirements.

[0027] S4: Input the three-dimensional curve atlas of the evaporating temperature Te of the unit with respect to the three parameters of the unit load rate L, the ambient dry-bulb temperature Ta, and the ambient relative humidity RH, and query the frost-free evaporating temperature Tei and the heating power q of the heat pump unit under this working condition Li , the power consumption p Li , and calculate the energy efficiency COP of the unit when there is no frost Li , COP Li = q Li / p Li .

[0028] S5: Determine whether the evaporating 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 evaporating 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 influence in the form of the defrost correction factor Fi. The calculation method of the defrost correction factor Fi is as Figure 4 shown.

[0029] S6: As Figure 4 shown, input the three-dimensional curve atlas of the defrost cycle duration τ of the unit with respect to the three parameters of the unit evaporating temperature Te, the ambient dry-bulb temperature Ta, and the ambient relative humidity RH; query the defrost cycle duration τ of the unit under this working condition i ; According to the obtained defrost cycle duration τ i , calculate the cumulative heat output Qi, the defrost heat consumption Qd, and the cumulative power consumption Wi during the cycle under the defrost working condition of the unit; Calculate the defrost correction factor Fi, Fi = (Qi – Qd) / Wi / COP Li .

[0030] S7: Calculate and record the comprehensive energy efficiency COPci of the heat pump unit, COPci = COP Li * Fi.

[0031] 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 factor Li of the heat pump unit for cyclic calculation. If so, select the maximum value from multiple COPcis obtained through cyclic calculation according to the program, so as to determine the optimal number of operating units of the system.

[0032] Embodiment 2 On the basis of Embodiment 1, taking 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.

[0033] The first step: Determine the input conditions: n = 8, ambient dry-bulb temperature Ta = 5 °C, ambient relative humidity RH = 80%, water outlet temperature of the unit Tw = 45 °C, and calculate the air dew point temperature Td = 1.84 °C; The 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 main building heating pipe and the main pipe flow rate M = 400 m³ / h; The third step: Calculate the building load Lb = CM(Ts - Tr) = 2333 kW; The fourth step: According to the performance curve of the unit sample, calculate the heating capacity q = 658 kW of the heat pump unit under full load operation under the conditions of ambient dry-bulb temperature Ta = 5 °C, ambient relative humidity RH = 80%, and water outlet temperature of the unit Tw = 45 °C; The fifth step: Calculate L1 = Lb / 1 / q = 3.54; The sixth step: Judge and find that L1 ≥ 1, let i = 2, and re-calculate the above steps in a loop. After calculation, it is found that until i = 4, after judgment, it is found that L4 = 0.89 ≤ 1; The seventh step: Input the three-dimensional curve atlas of the evaporation temperature Tei of the unit with respect to the three parameters of the unit load factor L, 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; The eighth step: Query that the unit load factor of the unit under this condition is 89%, the heating power qL4 = 615 kW and the power consumption pL4 = 187 kW of the unit without frosting operation, and COP = 3.29; The ninth step: Judge that Te4 = -5 °C < 0, and Te4 < Td, so the unit is in the frosting condition; The tenth step: Calculate the defrost correction coefficient F4, and input the three-dimensional curve atlas of the defrost cycle duration of the unit with respect to the three parameters of the evaporation temperature Te of the unit, ambient dry-bulb temperature Ta, and ambient relative humidity RH; The eleventh step: Query the defrosting cycle duration τ4 = 40 min of the unit under this operating condition. When the unit is in the defrosting operating condition, calculate the cumulative heat output Q4 = 268 kWh, the defrosting heat consumption Qd = 55 kWh, and the cumulative power consumption W4 = 125 kWh for one cycle; The twelfth step: Calculate and obtain the defrosting correction coefficient F4 = 0.65; The thirteenth step: Through cyclic calculation, obtain the comprehensive energy efficiency COPc4 = 2.15, COPc5 = 2.17, COPc6 = 2.21, COPc7 = 2.17, and COPc8 = 2.12; The fourteenth step: As shown in Figure 5 the figure, by comparison, when obtaining the maximum value of COPc, the value of i is 6, and set the number of operating units n = 6.

[0034] It can be seen from this embodiment that for a project using multiple air source heat pump units, when the building load is not at full load, through the above optimization control method, the beneficial result of significantly improving the comprehensive energy efficiency of the unit can be achieved.

[0035] Embodiment 3 An electronic device includes a processor, a network interface, and a memory. The processor, the network interface, and the memory are interconnected. Among them, the memory is used to store a computer program, and the computer program includes program instructions. The processor is configured to call the program instructions to execute the control method described in Embodiment 1.

[0036] A computer-readable storage medium includes a stored computer program. When the computer program runs, it controls the device where the computer-readable storage medium is located to execute the control method described in Embodiment 1.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An operation control method based on optimizing the load rate of an air source heat pump, 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 factor Li of the heat pump unit in the case of turning on 1 unit; S3: Judge whether the calculated load factor Li of the heat pump unit is ≤ 1. If so, go to step S4. If not, the number of heat pump units turned on i becomes i + 1, and recalculate the load factor Li of the heat pump unit; S4: Input the three-dimensional curve atlas of the evaporation temperature Te of the unit varying with three parameters: the unit load ratio L, the ambient dry-bulb temperature Ta, and the ambient relative humidity RH, and query the evaporation temperature Tei and the heating power q of the heat pump unit operating without frost under the current working conditions Li , the power consumption p Li , and calculate the energy efficiency COP of the unit without frost Li ; S5: Judge whether the evaporation temperature Tei satisfies Tei < Td and Tei < 0. If so, go to step S6. If not, the defrost correction factor Fi = 1.0, and directly go to step S7; S6: Calculate the defrost correction factor Fi, where Fi = (Qi – Qd) / Wi / COP Li , where Qi is the cumulative periodic heating capacity of the unit under the defrosting condition, Qd is the defrosting heat consumption of the unit under the defrosting condition, and Wi is the cumulative periodic power consumption of the unit under the defrosting condition; 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, the number of heat pump units turned on i becomes i + 1, and return to the step of calculating the load factor Li of the heat pump unit for cyclic calculation. If so, select the maximum value from the multiple COPci obtained by cyclic calculation according to the program, so as to determine the optimal number of units turned on for the system.

2. The operation control method based on the optimization of the air source heat pump load rate according to claim 1, wherein In steps S2 and S3, the calculation method of the load factor 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 operating at full load 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 factor Li of the heat pump unit: Li = Lb / i / q.

3. The operation control method based on the optimization of the air source heat pump load rate according to claim 1, wherein In step S4, the energy efficiency COP of the frost-free unit Li is calculated by the formula: COP Li =q Li / p Li。 4. The operation control method based on the optimization of the air source heat pump load rate according to claim 1, wherein, In step S6, the calculation method of the defrost correction factor Fi is as follows: Input the three-dimensional curve map of the defrost cycle duration τ of the unit varying with the three parameters of the evaporation temperature Te, the ambient dry-bulb temperature Ta, and the ambient relative humidity RH; Query the defrost cycle duration τ of the unit under the current operating conditions i ; According to the obtained defrosting cycle duration τ i , calculate the cumulative cycle heating capacity Qi, defrosting heat consumption Qd and cumulative cycle power consumption Wi of the unit under defrosting conditions; Calculate the defrost correction factor Fi, Fi = (Qi - Qd) / Wi / COPLi.

5. An electronic device, characterized in that, It includes a processor, a network interface, and a memory. 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. The processor is configured to call the program instructions to execute the control method according to any one of claims 1 - 4.

Images