Energy-saving operation method of variable frequency heating ventilation air conditioner and related device

Abstract

This invention discloses an energy-saving operation method and related equipment for a variable frequency HVAC system. The method includes: obtaining the target total load of the variable frequency HVAC system; calculating the test energy efficiency ratio (EER) of the chillers in different groups when the target total load is reached; obtaining the high-efficiency EERs (HERs) among the test EERs that are greater than a preset EER, and calculating the high-efficiency operating range of the test chillers based on the HERs; if the current load rate of the currently operating chillers is not within the high-efficiency operating range and the number meets a preset requirement, then controlling the number of currently operating chillers to increase or decrease based on the current load rate; obtaining the number of times the currently operating chillers are started within a preset time period, and if the preset number requirement is met, then starting the variable frequency HVAC system. This invention sets the number of operating chillers in the variable frequency HVAC system based on the load rate of the chillers, enabling the chillers to always operate within the high-efficiency range, achieving true energy saving.

Description

Technical Field

[0001] This invention relates to the field of air conditioning energy-saving technology, and in particular to an energy-saving operation method, system, variable frequency HVAC system, and computer-readable storage medium. Background Technology

[0002] Currently, a large portion of data center air conditioning systems still utilize chilled water systems. These systems primarily consist of cooling towers, cooling water pumps, chiller units, refrigerated pumps, and terminal precision air conditioners. The energy consumption of data center air conditioning systems accounts for a significant portion of total operating energy consumption. With increasingly stringent requirements for PUE (Power Usage Effectiveness), higher demands are being placed on the energy-efficient operation of data center air conditioning systems. In current water-cooled air conditioning systems, most equipment now employs variable frequency drives (VFDs), such as VFD chillers, VFD pumps, and VFD cooling towers.

[0003] Traditional equipment addition / reduction logic (adding or removing chillers) is based on the percentage of operating current or outlet water temperature. Adding a chiller occurs when the chiller's operating current reaches 95%–105% of its rated current, or when the outlet water temperature reaches the set value plus the error dead zone value. Using this traditional strategy, the chiller's actual operating condition is close to 100% of its rated operating condition.

[0004] However, at this time, the frequency converter is not energy-efficient because the frequency converter has certain losses, which means that the frequency converter is not as energy-efficient as the power frequency converter when operating at 100% capacity, and the frequency converter cannot give full play to its advantages.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] The main objective of this invention is to provide an energy-saving operation method, system, variable frequency HVAC system, and computer-readable storage medium for variable frequency HVAC systems, aiming to solve the problem that variable frequency HVAC systems cannot maintain a high-efficiency operating state for a long time in the prior art, resulting in energy-inefficient variable frequency HVAC systems.

[0007] To achieve the above objectives, the present invention provides an energy-saving operation method for a variable frequency HVAC system, the energy-saving operation method comprising the following steps:

[0008] Obtain the target total load of the variable frequency HVAC system, and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached, wherein the number of test chillers in different groups is different;

[0009] Obtain the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and calculate the high-efficiency operating range of the load rate of the test chiller based on the high-efficiency energy efficiency ratios;

[0010] The current load rate of the currently running chiller is obtained. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chillers meets the preset number, the number of currently running chillers is increased or decreased according to the current load rate.

[0011] The number of times the currently running chiller is started within a preset time period is obtained. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

[0012] Optionally, the energy-saving operation method for the variable frequency HVAC system includes obtaining the target total load of the variable frequency HVAC system and calculating the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. Specifically, the number of test chillers differs in different groups.

[0013] Obtain the target total load of the variable frequency HVAC system and group the test chillers in the variable frequency HVAC system, wherein the number of test chillers in different groups is different;

[0014] Control a different number of test chillers in each group to run at the target total load, calculate the first test load rate when a different number of test chillers in each group reach the target total load, and calculate the test energy efficiency ratio corresponding to the first test load rate based on the first test load rate.

[0015] Optionally, the energy-saving operation method for the variable frequency HVAC system, wherein obtaining the high-efficiency energy efficiency ratio (HER) among the tested HERs that is greater than a preset HER, and calculating the high-efficiency operating range of the tested chiller based on the HER, specifically includes:

[0016] The tested energy efficiency ratio is compared with the preset energy efficiency ratio, and the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratio are extracted from the tested energy efficiency ratios.

[0017] Calculate the second test load rate corresponding to the high efficiency energy efficiency ratio based on the high efficiency energy efficiency ratio, and obtain the high efficiency operating range of the test chiller based on the second test load rate.

[0018] Optionally, the energy-saving operation method for the variable frequency HVAC system, wherein obtaining the current load rate of the currently operating chiller, and when the current load rate is not within the high-efficiency operating range and the number of currently operating chillers meets a preset number, then controlling the number of currently operating chillers to increase or decrease according to the current load rate, specifically includes:

[0019] Obtain the current load rate of the currently operating chiller and the number of currently operating chillers;

[0020] If the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is lower than the first threshold of the high-efficiency operating range of the load rate;

[0021] If the current load rate is lower than the first threshold and the number of currently operating chiller units is less than the first preset number, then the number of currently operating chiller units is incremented by one.

[0022] Alternatively, if the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is higher than the second threshold of the high-efficiency operating range of the load rate;

[0023] If the current load rate is higher than the second threshold and the number of currently operating chiller units is greater than the second preset number, control the number of currently operating chiller units to be reduced by one.

[0024] Wherein, the first threshold is less than the second threshold, and the first preset quantity is greater than the second preset quantity.

[0025] Optionally, the energy-saving operation method for variable frequency HVAC systems, wherein after obtaining the current load rate of the currently operating chiller and the number of currently operating chillers, further includes:

[0026] If the current load rate is within the high-efficiency operating range of the load rate, then the number of currently operating chillers will be controlled to continue to operate normally.

[0027] Optionally, the energy-saving operation method for the variable frequency HVAC system, wherein obtaining the number of times the currently operating chiller is started within a preset time, and if the number of starts meets the preset number requirement, then starting the currently operating chiller to perform a variable frequency HVAC system with an increased or decreased number of units, specifically includes:

[0028] The number of times the number of currently running chillers increases or decreases within a preset time period is obtained, and it is determined whether the number of startups meets the preset number requirement.

[0029] If the number of startups meets the preset number requirement, an equipment operation command is issued, and the currently running chiller is started according to the equipment operation command to perform variable frequency HVAC after increasing or decreasing the number.

[0030] Optionally, the energy-saving operation method for the variable frequency HVAC system, wherein obtaining the number of times the currently operating chiller is started within a preset time, and if the number of starts meets the preset number requirement, then starting the currently operating chiller to perform a variable frequency HVAC system with an increased or decreased number of units, further includes:

[0031] If the number of startups does not meet the preset requirement, a device shutdown command will be issued.

[0032] According to the equipment shutdown command, the variable frequency HVAC system suspends the start of the currently running chiller main unit after increasing or decreasing the number of units, and waits for the load rate of the currently running chiller main unit to be refreshed. When the number of start-ups of the currently running chiller main unit meets the preset number requirement, the variable frequency HVAC system starts the currently running chiller main unit after increasing or decreasing the number of units.

[0033] Furthermore, to achieve the above objectives, the present invention also provides an energy-saving operation system for a variable frequency HVAC system, wherein the energy-saving operation system for the variable frequency HVAC system includes:

[0034] The test energy efficiency ratio acquisition module is used to acquire the target total load of the variable frequency HVAC system and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. The number of test chillers is different in different groups.

[0035] The high-efficiency operating range acquisition module is used to acquire the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and to calculate the load rate high-efficiency operating range of the test chiller based on the high-efficiency energy efficiency ratios.

[0036] The chiller unit addition / subtraction module is used to obtain the current load rate of the currently running chiller unit. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chiller units meets the preset number, the module controls the number of currently running chiller units to be increased or decreased according to the current load rate.

[0037] The variable frequency HVAC start-up module is used to obtain the number of times the currently running chiller is started within a preset time. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

[0038] In addition, to achieve the above objectives, the present invention also provides a variable frequency HVAC system, wherein the variable frequency HVAC system includes: a memory, a processor, and an energy-saving operation program of the variable frequency HVAC system stored in the memory and executable on the processor. When the energy-saving operation program of the variable frequency HVAC system is executed by the processor, it implements the steps of the energy-saving operation method of the variable frequency HVAC system as described above.

[0039] In addition, to achieve the above objectives, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores an energy-saving operation program for a variable frequency HVAC system, and when the energy-saving operation program for the variable frequency HVAC system is executed by a processor, it implements the steps of the energy-saving operation method for the variable frequency HVAC system as described above.

[0040] In this invention, the target total load of the variable frequency HVAC system is obtained, and the test energy efficiency ratio (EER) of the test chillers in different groups is calculated when the target total load is reached. The number of test chillers in different groups is different. The high-efficiency EERs (HERs) greater than a preset EER are obtained from the test EERs, and the high-efficiency operating range of the test chillers is calculated based on the HERs. The current load rate of the currently operating chillers is obtained. When the current load rate is not within the high-efficiency operating range and the number of currently operating chillers meets a preset requirement, the number of currently operating chillers is increased or decreased based on the current load rate. The number of times the currently operating chillers are started within a preset time period is obtained. If the number of starts meets a preset requirement, the variable frequency HVAC system with increased or decreased number of currently operating chillers is started. This invention calculates the high-efficiency operating range of the chiller's load rate and adjusts the number of chillers in operation based on the high-efficiency operating range using a new operating control logic. This helps to fully leverage the advantages of variable frequency HVAC systems, ensuring that the variable frequency equipment always operates within the high-efficiency range, thereby achieving energy-saving operation. Attached Figure Description

[0041] Figure 1 This is a flowchart of a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention;

[0042] Figure 2 This is a flowchart of the system logic control of a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention;

[0043] Figure 3 This is a schematic diagram illustrating the relationship between the number of operating devices and the cooling capacity in a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention.

[0044] Figure 4This is a schematic diagram illustrating the change in energy efficiency ratio with load rate of a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention.

[0045] Figure 5 This is a schematic diagram comparing the load rates of two schemes in a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention.

[0046] Figure 6 This is a schematic diagram showing the relationship between the number of equipment, the total power of the chiller station, and the cooling capacity of two preferred embodiments of the energy-saving operation method of the variable frequency HVAC system of the present invention.

[0047] Figure 7 This is a schematic diagram comparing the energy-saving rates at each stage of two schemes in a preferred embodiment of the energy-saving operation method of the variable frequency HVAC system of the present invention.

[0048] Figure 8 This is a structural diagram of a preferred embodiment of the energy-saving operation system of the variable frequency HVAC system of the present invention;

[0049] Figure 9 This is a structural diagram of a preferred embodiment of the variable frequency HVAC system of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0051] Currently, a large portion of data center air conditioning systems still utilize chilled water systems. These systems primarily consist of cooling towers, cooling water pumps, chiller units, refrigerated pumps, and terminal precision air conditioners. Air conditioning systems account for a significant portion of total energy consumption in data centers. With increasingly stringent requirements for PUE (Power Usage Effectiveness, a parameter characterizing the energy efficiency of data centers, calculated as the ratio of total electrical energy consumed by all electrical equipment to the total electrical energy consumed by all electronic information equipment), higher demands are being placed on the energy-efficient operation of data center air conditioning systems. In current water-cooled air conditioning systems, most equipment has adopted variable frequency drives (VFDs), such as VFD chillers, VFD pumps, and VFD cooling towers.

[0052] Traditional equipment addition / reduction logic (adding or removing chillers) is based on the percentage of operating current or outlet water temperature. Adding a chiller occurs when the chiller's operating current reaches 95%–105% of its rated current, or when the outlet water temperature reaches the set value plus the error dead zone value. Using this traditional strategy, the actual operating condition of the chiller is close to 100% of its rated operating condition.

[0053] However, at this time, the frequency converter is not energy-efficient because the frequency converter has certain losses. As a result, the frequency converter is not as energy-efficient as the power frequency converter when it is operating at 100% capacity. The frequency converter cannot give full play to its advantages. In view of the characteristics of the current frequency converter chiller, frequency converter water pump and cooling tower, this method adopts a new control operation logic, which enables the frequency converter to operate in the high-efficiency range, thereby achieving the purpose of energy saving.

[0054] The energy-saving operation method of the variable frequency HVAC system described in the preferred embodiment of the present invention, such as... Figure 1 and Figure 2 As shown, the energy-saving operation method of the variable frequency HVAC system includes the following steps:

[0055] Step S10: Obtain the target total load of the variable frequency HVAC system, and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. The number of test chillers in different groups is different.

[0056] In existing variable frequency chiller technology (mainly for variable frequency centrifugal chillers), the main control logic of the equipment is as follows: When the required cooling load (defined as the heat that must be removed from the room by the air conditioning system to maintain the building's thermal and humidity environment and required indoor temperature, or the amount of cooling that needs to be supplied to the room at a certain moment, including sensible heat and latent heat) is 100%, the variable frequency equipment operates at 50Hz, at which point the frequency conversion is equivalent to the power frequency. When the load is between approximately 60% and 100% (different manufacturers have different ranges for frequency conversion adjustment), the frequency converter adjusts its output frequency (higher frequency output for higher load, lower frequency output for lower load) to keep the guide vanes fully open, controlling the unit's load through frequency control. When the load drops below 60%, the guide vanes begin to gradually close (by closing the regulating valve to reduce refrigerant flow, thereby reducing the generated cooling capacity). When the load continues to decrease to an even lower level, to avoid compressor surge due to excessively low load, the speed will be appropriately increased (increasing the motor speed of the variable frequency chiller compressor). Due to the combined adjustment of the guide vanes and the frequency converter, the operating load range of the equipment is expanded, and the operating efficiency of the chiller at partial load is also improved. However, the most efficient operating range of the equipment is not near 100% load, but rather between approximately 40% and 60% (referred to as the high-efficiency operating range in this invention).

[0057] Specifically, the target total load of the variable frequency HVAC system is obtained, and the test chillers in the variable frequency HVAC system are grouped, wherein the number of test chillers in different groups is different;

[0058] Control a different number of test chillers in each group to run at the target total load, calculate the first test load rate when a different number of test chillers in each group reach the target total load, and calculate the test energy efficiency ratio corresponding to the first test load rate based on the first test load rate.

[0059] In this invention, a calculation comparison method is used to compare the operating data under two operating conditions (using different numbers of chiller units), and finally analyze the operating data and results.

[0060] This invention assumes that a project uses 5 centrifugal chillers in a 4+1 configuration (4 main chillers and 1 standby), with a single chiller capacity of 2500KW, a total cooling capacity of 10000KW, a rated COP of 5.24 (COP is the energy efficiency ratio), and a rated power of 477KW. The chilled water pumps and cooling water pumps use the same configuration, also 4+1, with a rated power of 70KW. The cooling towers also use the same configuration, with a rated power of 60KW.

[0061] Option 1 (existing technology) adopts a 100% load operation mode. In this mode, the number of chilled water pumps, cooling water pumps, and cooling towers turned on is equal to the number of chiller units turned on. In order to avoid the water pumps operating at too low a frequency at low load, resulting in insufficient water flow to the chiller units, the minimum frequency of chilled water pumps and cooling water pumps is limited to 30Hz, and the minimum frequency of cooling towers is limited to 25Hz.

[0062] like Figure 3 For scheme 1 ( Figure 3 (The broken line part of A) and Scheme 2 ( Figure 3 The section with two operating modes (the broken line section in the middle B) is the interval between the additional machines.

[0063] Option 1, in accordance with design requirements, always keeps one unit in standby mode (i.e., controls a maximum of four chiller units to operate simultaneously).

[0064] Option 2 involves adding more chillers when the chiller reaches approximately 45% load, aiming to maintain the equipment at around 45% load. The number of operating cooling water pumps, chilled water pumps, and cooling towers is the same as that of the chiller. The minimum frequency for chilled water pumps and cooling water pumps is maintained at 30Hz, and the minimum frequency for cooling towers is maintained at 25Hz. The maximum number of units operating in Option 2 is 5 (meaning that a standby chiller can be used while the primary chiller is running simultaneously).

[0065] Step S20: Obtain the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and calculate the high-efficiency operating zone of the load rate of the test chiller based on the high-efficiency energy efficiency ratios.

[0066] When selecting a centrifuge, it is often based on 100% load, and additional centrifuges are added based on 100% load. As the energy consumption at the terminal increases, the centrifuge begins to increase the load, and additional centrifuges are added when it approaches 100% load. When the operating conditions of two machines are close to 100%, a third machine is started, and so on.

[0067] Based on the ratio of speed to energy consumption of frequency converter equipment: When the equipment speed is reduced to 70% of the original speed, the power consumption will be reduced to 0.343 times the original power consumption, and the energy consumption will be greatly reduced.

[0068] This invention employs a new control logic for adding or removing equipment to keep the equipment operating in the high-efficiency zone, thereby improving overall operating energy efficiency and reducing operating power consumption.

[0069] Specifically, the tested energy efficiency ratio is compared with the preset energy efficiency ratio, and the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratio are extracted from the tested energy efficiency ratios.

[0070] Calculate the second test load rate corresponding to the high efficiency energy efficiency ratio based on the high efficiency energy efficiency ratio, and obtain the high efficiency operating range of the test chiller based on the second test load rate.

[0071] like Figure 4 As shown, the centrifuge COP (coefficient of performance) versus load rate curve is assumed to be as follows (the high efficiency point is different for different equipment); the high efficiency operating range of the test chiller can be determined based on the curve of the relationship between the COP and the load rate.

[0072] Step S30: Obtain the current load rate of the currently running chiller. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chillers meets the preset number, the number of currently running chillers is increased or decreased according to the current load rate.

[0073] Specifically, the current load rate of the currently operating chiller and the number of currently operating chillers are obtained.

[0074] If the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is lower than the first threshold of the high-efficiency operating range of the load rate.

[0075] If the current load rate is lower than the first threshold and the number of currently operating chiller units is less than the first preset number, then the number of currently operating chiller units is incremented by one.

[0076] When the current load rate is not within the high-efficiency operating range of the load rate, it is necessary to determine whether the chiller meets the start-stop logic. The start-stop logic includes determining the number of available devices. Assuming there are 5 units on site, the minimum number of operating units is 1 and the maximum number of operating units is 5. However, this may include unavailable devices, which include faulty devices and devices under maintenance. In other words, when the number of chiller units needs to be increased or decreased, it is necessary to determine whether it is possible to increase or decrease. For example, if the number of chiller units currently operating is 1, then the number of chiller units cannot be reduced. Or, if the number of chiller units currently operating is 5, then the number of chiller units cannot be increased.

[0077] Alternatively, if the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is higher than the second threshold of the high-efficiency operating range of the load rate.

[0078] If the current load rate is higher than the second threshold and the number of currently operating chiller units is greater than the second preset number, the number of currently operating chiller units is reduced by one.

[0079] Wherein, the first threshold is less than the second threshold, and the first preset quantity is greater than the second preset quantity.

[0080] If the current load rate is within the high-efficiency operating range of the load rate, then the number of currently operating chillers will be controlled to continue to operate normally.

[0081] like Figure 5 As shown, Scheme 1 ( Figure 5 The middle section (part A) added chillers at total cooling capacities of 2400KW, 5000KW, and 7400KW respectively. (The first addition was when one chiller reached 2400KW and the total cooling capacity of one chiller was 2500KW; the second addition was when two chillers reached 5000KW and the third addition was when three chillers reached 7500KW, all of which were added only when the chillers were close to full load.) The maximum number of chillers in operation was 4.

[0082] Option 2 ( Figure 5(Part B of the broken line) Additional units were added at 1600KW, 3200KW, 4800KW, and 6200KW. (The first addition resulted in a load rate of 64%, followed by a load rate of 32% (1600 / 2500 / 2 = 32%). The second addition resulted in a load rate of 43% (3200 / 2500 / 3 = 43%). The third addition resulted in a load rate of 48% (4800 / 2500 / 4 = 48%). Except for the first addition, which operated between 32% and 64%, all other additions operated within the high-efficiency range of around 45%.) This application also put standby equipment into use, with a maximum of 5 units activated. Although the equipment was activated earlier, increasing the total number of operating units, each unit maintained a low load rate.

[0083] Depend on Figure 5 As can be seen, in the traditional operating mode ( Figure 5 (Part A of the broken line), the host load rate is maintained between 0.5 and 1.0. After optimization ( Figure 5 (Part B of the middle zigzag line) The load rate of the host is maintained between 0 and 0.6 or between 0.32 and 0.64.

[0084] Comparing the total operating power consumption of the two schemes above, the total operating power consumption is equal to the sum of the operating power consumption of the chiller, the chilled water pump, the cooling water pump, and the cooling tower.

[0085] like Figure 6 As shown, when the total cooling capacity is below 1600KW, the number of devices is 1, and the power consumption curves overlap. Figure 6 (The front sections of A1 and A2 overlap). When the power exceeds 1600KW, the optimized solution of this invention starts two devices, reducing the load rate of a single device and increasing the COP value of the device. Although the number of devices increases, the total power consumption is still reduced.

[0086] When the total cooling capacity demand is large, for example, around 7400KW, if the original solution (existing technology) is used, then 3 devices will be operating, with each device having a load rate of approximately 99%, and the total power consumption will be approximately 2012.52KW. If the optimized solution (the solution of this invention) is used, then 4 devices will be operating, with each device having a load rate of approximately 59%, and the total power consumption will be approximately 986.23KW, resulting in energy savings of approximately 51.00%.

[0087] Comparing the energy saving rates at each stage, the energy saving rate = (total power consumption before optimization - total power consumption after optimization) / total power consumption before optimization. In the conventional market, the energy saving rate is generally 3%-25%.

[0088] like Figure 7As shown, when the number of chiller units in the two sets is the same, the total operating power of the existing technical solution and the solution of this invention is the same, and there is no room for energy saving. Except for the time period when the number of units is the same, the energy saving rate is high at other times.

[0089] Step S40: Obtain the number of times the currently running chiller unit is started within a preset time. If the number of starts meets the preset number requirement, start the currently running chiller unit to perform variable frequency HVAC after increasing or decreasing the number.

[0090] The number of starts refers to the number of times a unit can be started within a unit time. The value varies depending on the equipment manufacturer. Here, it is preferred that the unit can start and stop at a time interval of 10 minutes, that is, start once every 10 minutes.

[0091] Specifically, the number of times the number of currently running chillers increases or decreases within a preset time period is obtained, and it is determined whether the number of startups meets the preset number requirement.

[0092] If the number of startups meets the preset number requirement, an equipment operation command is issued, and the currently running chiller is started according to the equipment operation command to perform variable frequency HVAC after increasing or decreasing the number.

[0093] If the number of startups does not meet the preset requirement, a device shutdown command will be issued.

[0094] According to the equipment shutdown command, the variable frequency HVAC system suspends the start of the currently running chiller main unit after increasing or decreasing the number of units, and waits for the load rate of the currently running chiller main unit to be refreshed. When the number of start-ups of the currently running chiller main unit meets the preset number requirement, the variable frequency HVAC system starts the currently running chiller main unit after increasing or decreasing the number of units.

[0095] This method describes a unit number control method based on the optimal energy efficiency of the chiller. In practical engineering applications, the optimal operating range is set according to different equipment, and the terminal load of the chiller is matched with the optimal operating range of the chiller to ensure that the chiller is kept within the optimal operating range. By reducing the total power consumption of the equipment through frequency conversion, the purpose of energy-saving operation is achieved.

[0096] This method primarily protects a variable frequency air conditioning system's on / off strategy, prioritizing the activation of the main unit to maintain operation within the high-efficiency range and achieve energy savings.

[0097] Furthermore, such as Figure 8 As shown, based on the above-mentioned energy-saving operation method for variable frequency HVAC systems, the present invention also provides an energy-saving operation system for variable frequency HVAC systems, wherein the energy-saving operation system for variable frequency HVAC systems includes:

[0098] The test energy efficiency ratio acquisition module 51 is used to acquire the target total load of the variable frequency HVAC system and calculate the test energy efficiency ratio of the test chiller in different groups when the target total load is reached. The number of test chillers in different groups is different.

[0099] The high-efficiency operating range acquisition module 52 is used to acquire the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and to calculate the load rate high-efficiency operating range of the test chiller based on the high-efficiency energy efficiency ratios.

[0100] The chiller unit addition / subtraction module 53 is used to obtain the current load rate of the currently running chiller unit. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chiller units meets the preset number, the module controls the number of currently running chiller units to be increased or decreased according to the current load rate.

[0101] The variable frequency HVAC start-up module 54 is used to obtain the number of times the currently running chiller is started within a preset time. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

[0102] Furthermore, such as Figure 9 As shown, based on the above-mentioned energy-saving operation method and system for variable frequency HVAC, the present invention also provides a variable frequency HVAC system, which includes a processor 10, a memory 20 and a display 30. Figure 9 Only some of the components of a variable frequency HVAC system are shown; however, it should be understood that it is not required to implement all of the components shown, and more or fewer components may be implemented instead.

[0103] In some embodiments, the memory 20 may be an internal storage unit of the variable frequency HVAC system, such as a hard drive or memory. In other embodiments, the memory 20 may be an external storage device of the variable frequency HVAC system, such as a plug-in hard drive, smart media card (SMC), secure digital (SD) card, flash card, etc. Further, the memory 20 may include both internal and external storage units of the variable frequency HVAC system. The memory 20 is used to store application software and various types of data installed in the variable frequency HVAC system, such as the program code for installing the variable frequency HVAC system. The memory 20 can also be used to temporarily store data that has been output or will be output. In one embodiment, the memory 20 stores an energy-saving operation program 40 for the variable frequency HVAC system, which can be executed by the processor 10 to implement the energy-saving operation method of the variable frequency HVAC system in this application.

[0104] In some embodiments, the processor 10 may be a central processing unit (CPU), a microprocessor, or other data processing chip, used to run program code stored in the memory 20 or process data, such as executing the energy-saving operation method of the variable frequency HVAC system.

[0105] In some embodiments, the display 30 may be an LED display, a liquid crystal display, a touch-screen liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. The display 30 is used to display information about the variable frequency HVAC system and to display a visual user interface. The components 10-30 of the variable frequency HVAC system communicate with each other via a system bus.

[0106] In one embodiment, when the processor 10 executes the energy-saving operation program 40 for the variable frequency HVAC system in the memory 20, the following steps are performed:

[0107] Obtain the target total load of the variable frequency HVAC system, and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached, wherein the number of test chillers in different groups is different;

[0108] Obtain the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and calculate the high-efficiency operating range of the load rate of the test chiller based on the high-efficiency energy efficiency ratios;

[0109] The current load rate of the currently running chiller is obtained. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chillers meets the preset number, the number of currently running chillers is increased or decreased according to the current load rate.

[0110] The number of times the currently running chiller is started within a preset time period is obtained. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

[0111] The process involves obtaining the target total load of the variable frequency HVAC system and calculating the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. The number of test chillers varies across different groups, specifically including:

[0112] Obtain the target total load of the variable frequency HVAC system and group the test chillers in the variable frequency HVAC system, wherein the number of test chillers in different groups is different;

[0113] Control a different number of test chillers in each group to run at the target total load, calculate the first test load rate when a different number of test chillers in each group reach the target total load, and calculate the test energy efficiency ratio corresponding to the first test load rate based on the first test load rate.

[0114] The step of obtaining the high-efficiency energy efficiency ratios (HERs) that are greater than the preset HERs in the test energy efficiency ratios, and calculating the high-efficiency operating range of the test chiller based on the HERs, specifically includes:

[0115] The tested energy efficiency ratio is compared with the preset energy efficiency ratio, and the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratio are extracted from the tested energy efficiency ratios.

[0116] Calculate the second test load rate corresponding to the high efficiency energy efficiency ratio based on the high efficiency energy efficiency ratio, and obtain the high efficiency operating range of the test chiller based on the second test load rate.

[0117] Specifically, the step of obtaining the current load rate of the currently operating chiller, and when the current load rate is not within the high-efficiency operating range and the number of currently operating chillers meets a preset requirement, involves controlling the number of currently operating chillers to increase or decrease based on the current load rate.

[0118] Obtain the current load rate of the currently operating chiller and the number of currently operating chillers;

[0119] If the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is lower than the first threshold of the high-efficiency operating range of the load rate;

[0120] If the current load rate is lower than the first threshold and the number of currently operating chiller units is less than the first preset number, then the number of currently operating chiller units is incremented by one.

[0121] Alternatively, if the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is higher than the second threshold of the high-efficiency operating range of the load rate;

[0122] If the current load rate is higher than the second threshold and the number of currently operating chiller units is greater than the second preset number, control the number of currently operating chiller units to be reduced by one.

[0123] Wherein, the first threshold is less than the second threshold, and the first preset quantity is greater than the second preset quantity.

[0124] The process of obtaining the current load rate of the currently operating chiller and the number of currently operating chillers further includes:

[0125] If the current load rate is within the high-efficiency operating range of the load rate, then the number of currently operating chillers will be controlled to continue to operate normally.

[0126] The step of obtaining the number of times the currently operating chiller unit is started within a preset time period, and if the number of starts meets the preset requirement, then starting the currently operating chiller unit for variable frequency HVAC after increasing or decreasing the number, specifically includes:

[0127] The number of times the number of currently running chillers increases or decreases within a preset time period is obtained, and it is determined whether the number of startups meets the preset number requirement.

[0128] If the number of startups meets the preset number requirement, an equipment operation command is issued, and the currently running chiller is started according to the equipment operation command to perform variable frequency HVAC after increasing or decreasing the number.

[0129] The process includes obtaining the number of times the currently operating chiller is started within a preset time period; if the number of starts meets the preset requirement, then starting the currently operating chiller for variable frequency HVAC after increasing or decreasing the number of units; and further includes:

[0130] If the number of startups does not meet the preset requirement, a device shutdown command will be issued.

[0131] According to the equipment shutdown command, the variable frequency HVAC system suspends the start of the currently running chiller main unit after increasing or decreasing the number of units, and waits for the load rate of the currently running chiller main unit to be refreshed. When the number of start-ups of the currently running chiller main unit meets the preset number requirement, the variable frequency HVAC system starts the currently running chiller main unit after increasing or decreasing the number of units.

[0132] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores an energy-saving operation program for a variable frequency HVAC system, and when the energy-saving operation program for the variable frequency HVAC system is executed by a processor, it implements the steps of the energy-saving operation method for the variable frequency HVAC system as described above.

[0133] In summary, this invention provides an energy-saving operation method and related equipment for a variable frequency HVAC system. The method includes: obtaining the target total load of the variable frequency HVAC system; calculating the test energy efficiency ratio (EER) of the test chillers in different groups when the target total load is reached, wherein the number of test chillers in different groups is different; obtaining the high-efficiency EER of the test EER that is greater than a preset EER, and calculating the high-efficiency operating range of the load rate of the test chillers based on the high-efficiency EER; obtaining the current load rate of the currently operating chillers; when the current load rate is not within the high-efficiency operating range of the load rate and the number of currently operating chillers meets a preset number, then controlling the number of currently operating chillers to increase or decrease based on the current load rate; obtaining the number of times the currently operating chillers are started within a preset time; if the number of starts meets a preset number requirement, then starting the variable frequency HVAC system after increasing or decreasing the number of currently operating chillers. This invention calculates the high-efficiency operating range of the chiller's load rate and uses a new operating control logic based on this high-efficiency operating range to adjust the number of chillers in operation. This helps to fully leverage the advantages of variable frequency HVAC systems, ensuring that the variable frequency equipment always operates within the high-efficiency range, thereby achieving energy-saving operation.

[0134] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or variable frequency heating and ventilation system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or variable frequency heating and ventilation system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or variable frequency heating and ventilation system that includes that element.

[0135] Of course, those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.). The program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The computer-readable storage medium can be a memory, magnetic disk, optical disk, etc.

[0136] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for energy saving operation of a variable frequency heating, ventilation and air conditioning system, characterized in that, The energy-saving operation method of the variable frequency HVAC system includes: Obtain the target total load of the variable frequency HVAC system, and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached, wherein the number of test chillers in different groups is different; Obtain the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and calculate the high-efficiency operating range of the load rate of the test chiller based on the high-efficiency energy efficiency ratios; The current load rate of the currently running chiller is obtained. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chillers meets the preset number, the number of currently running chillers is increased or decreased according to the current load rate. The number of times the currently running chiller is started within a preset time period is obtained. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

2. The energy saving operation method of a variable frequency heating, ventilation, and air conditioning system according to claim 1, wherein, The process involves obtaining the target total load of the variable frequency HVAC system and calculating the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. The number of test chillers varies across different groups, specifically including: Obtain the target total load of the variable frequency HVAC system and group the test chillers in the variable frequency HVAC system, wherein the number of test chillers in different groups is different; Control a different number of test chillers in each group to run at the target total load, calculate the first test load rate when a different number of test chillers in each group reach the target total load, and calculate the test energy efficiency ratio corresponding to the first test load rate based on the first test load rate.

3. The energy saving operation method of a variable frequency heating, ventilation, and air conditioning system according to claim 1, wherein The step of obtaining the high-efficiency energy efficiency ratios (HERs) that are greater than the preset HERs from the tested HERs, and calculating the high-efficiency operating range of the tested chiller's load rate based on the HERs, specifically includes: The tested energy efficiency ratio is compared with the preset energy efficiency ratio, and the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratio are extracted from the tested energy efficiency ratios. Calculate the second test load rate corresponding to the high efficiency energy efficiency ratio based on the high efficiency energy efficiency ratio, and obtain the high efficiency operating range of the test chiller based on the second test load rate.

4. The energy saving operation method of a variable frequency heating, ventilation and air conditioning system according to claim 1, wherein The process of obtaining the current load rate of the currently operating chiller, and when the current load rate is not within the high-efficiency operating range and the number of currently operating chillers meets a preset requirement, then controlling the number of currently operating chillers to increase or decrease based on the current load rate, specifically includes: Obtain the current load rate of the currently operating chiller and the number of currently operating chillers; If the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is lower than the first threshold of the high-efficiency operating range of the load rate; If the current load rate is lower than the first threshold and the number of currently operating chiller units is less than the first preset number, then the number of currently operating chiller units is incremented by one. Alternatively, if the current load rate is not within the high-efficiency operating range of the load rate, then determine whether the current load rate is higher than the second threshold of the high-efficiency operating range of the load rate; If the current load rate is higher than the second threshold and the number of currently operating chiller units is greater than the second preset number, control the number of currently operating chiller units to be reduced by one. Wherein, the first threshold is less than the second threshold, and the first preset quantity is greater than the second preset quantity.

5. The energy-saving operation method of a variable frequency heating, ventilation, and air conditioning system according to claim 4, wherein The process of obtaining the current load rate of the currently operating chiller and the number of currently operating chillers further includes: If the current load rate is within the high-efficiency operating range of the load rate, then the number of currently operating chillers will be controlled to continue to operate normally.

6. The energy saving operation method of a variable frequency heating, ventilation and air conditioning system according to claim 1, wherein, The step of obtaining the number of times the currently operating chiller is started within a preset time period, and if the number of starts meets the preset requirement, then starting the currently operating chiller for variable frequency HVAC after increasing or decreasing the number, specifically includes: The number of times the number of currently running chillers increases or decreases within a preset time period is obtained, and it is determined whether the number of startups meets the preset number requirement. If the number of startups meets the preset number requirement, an equipment operation command is issued, and the currently running chiller is started according to the equipment operation command to perform variable frequency HVAC after increasing or decreasing the number.

7. The energy-saving operation method of a variable frequency heating, ventilation, and air conditioning system according to claim 6, wherein The process involves obtaining the number of times the currently operating chiller unit is started within a preset time period. If the number of starts meets the preset requirement, the currently operating chiller unit is started to perform variable frequency HVAC operations with an increased or decreased number of units. The process further includes: If the number of startups does not meet the preset requirement, a device shutdown command will be issued. According to the equipment shutdown command, the variable frequency HVAC system suspends the start of the currently running chiller main unit after increasing or decreasing the number of units, and waits for the load rate of the currently running chiller main unit to be refreshed. When the number of start-ups of the currently running chiller main unit meets the preset number requirement, the variable frequency HVAC system starts the currently running chiller main unit after increasing or decreasing the number of units.

8. An energy-saving operation system of a variable frequency heating, ventilation and air conditioning, characterized in that, The energy-saving operation system of the variable frequency HVAC system includes: The test energy efficiency ratio acquisition module is used to acquire the target total load of the variable frequency HVAC system and calculate the test energy efficiency ratio of the test chillers in different groups when the target total load is reached. The number of test chillers is different in different groups. The high-efficiency operating range acquisition module is used to acquire the high-efficiency energy efficiency ratios that are greater than the preset energy efficiency ratios in the test energy efficiency ratios, and to calculate the load rate high-efficiency operating range of the test chiller based on the high-efficiency energy efficiency ratios. The chiller unit addition / subtraction module is used to obtain the current load rate of the currently running chiller unit. When the current load rate is not in the high-efficiency operating range of the load rate and the number of currently running chiller units meets the preset number, the module controls the number of currently running chiller units to be increased or decreased according to the current load rate. The variable frequency HVAC start-up module is used to obtain the number of times the currently running chiller is started within a preset time. If the number of starts meets the preset number requirement, the currently running chiller is started to perform variable frequency HVAC after the number is increased or decreased.

9. A variable frequency heating, ventilation, and air conditioning system, characterized by, The variable frequency HVAC system includes: a memory, a processor, and an energy-saving operation program for the variable frequency HVAC system stored in the memory and executable on the processor. When the energy-saving operation program for the variable frequency HVAC system is executed by the processor, it implements the steps of the energy-saving operation method for the variable frequency HVAC system as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores an energy-saving operation program for a variable frequency HVAC system, which, when executed by a processor, implements the steps of the energy-saving operation method for a variable frequency HVAC system as described in any one of claims 1-7.

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