Air Conditioning System

Abstract

To disclose an example of an air conditioning system capable of leveling cooling capacities generated by a plurality of air conditioners.SOLUTION: An air conditioning system can execute a thermo-off prohibition function. The thermo-off prohibition function is a control of prohibiting execution of a thermo-off function in a case when the number of times of execution of the thermo-off function is over a predetermined number of times within a predetermined time and a cooling capacity of the other air conditioner is larger than a predetermined lower limit value. Thus, for example, in a case when the thermo-off prohibition function is executed to the air conditioner 11A, the cooling capacity of the air conditioner 11A is kept at a time when the thermo-off prohibition function is executed. Accordingly, under the assumption that a heat generation amount in a server chamber is constant, the cooling capacity of the air conditioner 11B is gradually lowered. Thus, the cooling capacities generated in the plurality of air conditioners 11A, 11B can be leveled.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an air conditioning system in which a plurality of air conditioners perform air conditioning of the same room. [Background technology]

[0002] For example, in the air conditioning system described in Patent Document 1, when the compressor is frequently turned on and off, the compressor is continuously operated at the minimum operating frequency to prevent the compressor from being frequently turned on and off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5492625 Summary of the Invention [Problem to be solved by the invention]

[0004] In an air conditioning system in which a plurality of air conditioners draw in room air from the same room, cool the air that was drawn in, and supply it to the room, the cooling capacity generated by each air conditioner can vary greatly.

[0005] In other words, because the temperature of the indoor air is not uniform, the cooling capacity generated by an air conditioner that draws in high-temperature air and that draws in relatively low-temperature air differs. In view of the above, the present disclosure discloses an example of an air conditioning system that can equalize the cooling capacity generated by multiple air conditioners. [Means for solving the problem]

[0006] The air conditioning system includes a first air conditioner (11A) that draws in indoor air, cools the air, and supplies the cooled air to the room, a second air conditioner (11B) that draws in indoor air, cools the air, and supplies the cooled air to the room, a first temperature sensor that detects the temperature of the air before being cooled by the first air conditioner (11A) or the temperature of the air after being cooled by the first air conditioner (11A), and a second air conditioner (11B) that draws in indoor air, cools the air, and supplies the cooled air to the room, a first temperature sensor that detects the temperature of the air before being cooled by the first air conditioner (11A) or the temperature of the air after being cooled by the second air conditioner (11B), The control device (10, 16) is equipped with a second temperature sensor that detects the temperature of the air or the temperature of the air after it has been cooled by the second air conditioner (11B), and a control device (10, 16) that is capable of controlling the cooling capacity (hereinafter referred to as the first cooling capacity) generated by the first air conditioner (11A) and the cooling capacity (hereinafter referred to as the second cooling capacity) generated by the second air conditioner (11B), and that is capable of executing first air conditioner control, second air conditioner control, and thermo-off prohibition control.

[0007] The first air conditioner control is a control that controls the first cooling capacity within a predetermined range so that the temperature detected by the first temperature sensor (hereinafter referred to as the first temperature) becomes a predetermined temperature (hereinafter referred to as the first set temperature), and is capable of stopping the generation of the first cooling capacity (hereinafter referred to as the first thermo off) to set the first temperature to the first set temperature.

[0008] The second air conditioner control is a control that controls the second cooling capacity within a predetermined range so that the temperature detected by the second temperature sensor (hereinafter referred to as the second temperature) becomes a predetermined temperature (hereinafter referred to as the second set temperature), and is capable of stopping the generation of the second cooling capacity (hereinafter referred to as the second thermo off) to set the second temperature to the second set temperature.

[0009] The thermo-off prohibition control is control that prohibits the execution of the first thermo-off when the number of times the first thermo-off is executed exceeds a predetermined number of times within a predetermined time and the second cooling capacity is greater than a predetermined lower limit value, or control that prohibits the execution of the second thermo-off when the number of times the second thermo-off is executed exceeds a predetermined number of times within a predetermined time and the first cooling capacity is greater than a predetermined lower limit value.

[0010] As a result, for example, when the thermo-off prohibition control is executed for the first thermo-off, the first cooling capacity is maintained when the thermo-off prohibition control is executed. Therefore, if the amount of heat generated in the room is constant, the second cooling capacity is gradually reduced by executing the second air conditioner control. Therefore, the cooling capacity generated by the multiple air conditioners (11A, 11B) can be leveled out.

[0011] Incidentally, the symbols in the above parentheses are examples showing the corresponding relationship with the specific configurations etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations etc. shown by the symbols in the above parentheses. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing an air conditioning system according to a first embodiment. [Diagram 2] 4 is a flowchart showing an example of control of the air conditioning system according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following "embodiment of the invention" shows an example of an embodiment that falls within the technical scope of the present disclosure. In other words, the invention-specific matters described in the claims are not limited to the specific configurations and structures shown in the following embodiment.

[0014] At least one of each of the components or parts described with a reference number is provided, unless otherwise specified by "one". In other words, unless otherwise specified by "one", the component may be provided in two or more. The air conditioning system shown in this disclosure includes at least the components described with a reference number, as well as the structural elements shown in the drawings.

[0015] (First embodiment) <1. Overview of the air conditioning system> In this embodiment, an example of an air conditioning system according to the present disclosure is applied to an air conditioning system for conditioning a server room such as a data center or a communication equipment room. As shown in FIG. 1, the air conditioning system 1 includes a plurality of air conditioners 11 and an integrated control unit 10.

[0016] Each air conditioner 11 is a so-called "package air conditioner" configured with a vapor compression type refrigeration machine. Note that each of the multiple air conditioners 11 according to this embodiment (two in this embodiment) is a vapor compression type refrigeration machine with the same configuration and specifications.

[0017] Each air conditioner 11 generates cold heat or hot heat (cold heat in this embodiment) for air conditioning in the server room. Each of the multiple air conditioners 11 draws in air in the same server room, cools the air, and then supplies the cooled air to the room.

[0018] Hereinafter, when any one or all of the multiple air conditioners 11 are intended, they will be referred to as air conditioner 11. When a specific air conditioner among the multiple air conditioners 11 is intended, they will be referred to as air conditioner 11A or air conditioner 11B.

[0019] The air conditioner 11 includes a compressor 12, a condenser 13, a pressure reducer 14, an evaporator 15, a first fan 13f, a second fan 15f, a control unit 16, an intake temperature sensor S1, and an exhaust temperature sensor S2.

[0020] The compressor 12 compresses a low-pressure gas-phase refrigerant and supplies it to the condenser 13. The compressor 12 is driven by an electric motor (not shown). The electric motor is driven by an inverter-type drive circuit (not shown). The operation of the drive circuit is controlled by the control unit 16.

[0021] The drive circuit supplies a drive current to the electric motor and is capable of changing the frequency of the drive current (hereinafter referred to as the drive frequency). The drive circuit supplies the electric motor with a drive current having a drive frequency corresponding to a command frequency from the control unit 16. In other words, the operation of the compressor 12 is controlled by the control unit 16 via the drive circuit.

[0022] The condenser 13 is a high-pressure side heat exchanger that cools the high-pressure refrigerant compressed by the compressor 12. In the condenser 13, the gas-phase refrigerant is cooled and liquefied (condensed). The pressure reducer 14 reduces the pressure and expands the high-pressure refrigerant flowing out from the condenser 13, and supplies it to the evaporator 15.

[0023] The evaporator 15 evaporates the low-pressure refrigerant in liquid phase to generate cold, i.e., cooling capacity. The first fan 13f blows air for cooling to the condenser 13. The second fan 15f draws in air from within the server room and supplies it to the evaporator 15, and also supplies the air cooled by the evaporator 15 to the server room.

[0024] The control unit 16 controls at least the compressor 12 and the second fan 15f. Detection signals of the suction temperature sensor S1 and the discharge temperature sensor S2 are input to the control unit 16. The control unit 16 controls the compressor 12 and the second fan 15f by utilizing the detection signals.

[0025] The suction temperature sensor S1 detects the temperature of the air before it is cooled by the evaporator 15. The discharge temperature sensor S2 detects the temperature of the air after it is cooled by the evaporator 15. Hereinafter, the temperature detected by the suction temperature sensor S1 is referred to as the suction temperature Ti. The temperature detected by the discharge temperature sensor S2 is referred to as the discharge temperature To.

[0026] The control unit 16 is configured with a microcomputer having a CPU, a ROM, a RAM, etc. The following controls and functions are realized by the CPU executing software stored in a non-volatile storage unit such as a ROM.

[0027] <2. Air conditioning system control operation> <2.1 Overview of compressor control> The control unit 16 can control the compressor 12 using a suction priority control function (hereinafter also referred to as a normal control function), a thermo-off function, a thermo-on function, or a thermo-off prohibition function. The suction priority control function controls the magnitude of the cooling capacity generated by the evaporator 15.

[0028] The thermo-off function is a control for stopping the compressor 12 to stop the generation of cooling capacity. The thermo-on function is a control for starting the compressor 12 that has been stopped by the thermo-off function to generate cooling capacity. The thermo-off prohibition function is a control for stopping the execution of the thermo-off function.

[0029] <Suction priority control function (normal control function)> In the suction priority control function, the control unit 16 controls the rotation speed of the compressor 12 between a predetermined lower limit rotation speed and an upper limit rotation speed so that the suction temperature Ti becomes a predetermined temperature (hereinafter referred to as the set temperature Ts).

[0030] In other words, the control unit 16 controls the cooling capacity generated by the evaporator 15 between a lower limit value and an upper limit value so that the suction temperature Ti becomes the set temperature Ts. Incidentally, the second blower 15f is controlled so that the "difference between the suction temperature Ti and the blowing temperature To" or the "difference between the set temperature T and the blowing temperature To" falls within a predetermined temperature range.

[0031] The set temperature Ts for the air conditioner 11A and the set temperature Ts for the air conditioner 11B may be the same or different. Similarly, the lower limit (lower limit rotation speed) and upper limit (upper limit rotation speed) of the cooling capacity for the air conditioner 11A and the lower limit (lower limit rotation speed) and upper limit (upper limit rotation speed) of the cooling capacity for the air conditioner 11B may be the same or different.

[0032] <Thermo-off function> In the thermo-off function, when a predetermined condition (hereinafter referred to as a stop condition) is satisfied for a predetermined period of time, that is, when the thermo-off condition is satisfied, the control unit 16 stops the compressor 12 to stop the generation of cold heat. The stop condition is a necessary condition for the thermo-off function to be executed.

[0033] In addition, the stop condition in this embodiment refers to a state in which the temperature condition is satisfied such that the suction temperature Ti is equal to or lower than a predetermined temperature (hereinafter referred to as the thermo-off temperature Tc) and the rotation speed of the compressor 12 is equal to or lower than the lower limit rotation speed.

[0034] The thermo-off temperature Tc is the same as the set temperature Ts or a temperature lower than the set temperature Ts. The thermo-off temperature Tc for the air conditioner 11A and the thermo-off temperature Tc for the air conditioner 11B may be the same or different temperatures.

[0035] The control unit 16 according to this embodiment grasps the "rotation speed of the compressor 12" from the drive frequency. That is, the control unit 16 stops the compressor 12 when the suction temperature Ti falls to or below the thermo-off temperature Tc and the drive frequency remains below a frequency corresponding to the lower limit rotation speed (hereinafter referred to as the minimum frequency) for a predetermined period of time.

[0036] Specifically, when the suction temperature Ti is lower than the set temperature Ts, the control unit 16 reduces the rotation speed of the compressor 12 to reduce the cooling capacity so that the suction temperature Ti becomes the set temperature Ts. At this time, when the state in which the suction temperature Ti falls to or below the thermo-off temperature Tc and the drive frequency is equal to or below the minimum frequency continues for a predetermined time, the control unit 16 stops the compressor 12.

[0037] <Thermo-on function> This function starts the compressor 12 to generate cold heat when the suction temperature Ti exceeds a predetermined temperature (hereinafter referred to as the start-up temperature). The start-up temperature is a temperature obtained by adding a predetermined value equal to or greater than 0 to the thermo-off temperature Tc. After the compressor 12 is started by the thermo-on function, the suction priority control function is executed.

[0038] <Thermo-off prohibition function> With the thermo-off prohibition function, for example, if the number of times the thermo-off function is executed in air conditioner 11A exceeds a predetermined number of times within a predetermined time period and the drive frequency of compressor 12 of air conditioner 11B is higher than the minimum frequency, execution of the thermo-off function in air conditioner 11A is prohibited.

[0039] When the thermo-off prohibition function is executed in the air conditioner 11A, the compressor 12 of the air conditioner 11A continues to operate with the minimum frequency maintained. On the other hand, the normal control function is executed in the air conditioner 11B.

[0040] Then, after air conditioner 11A starts executing the thermo-off prohibition function, when the cooling capacity generated by air conditioner 11B increases due to the normal control function being executed by air conditioner 11B, the thermo-off prohibition function being executed by air conditioner 11A is stopped.

[0041] The reason is that if the cooling capacity generated by the air conditioner 11B increases while the thermo-off prohibition function is being executed in the air conditioner 11A, there is a high possibility that the amount of heat generated in the server room has increased.

[0042] Therefore, in this case, if the thermo-off prohibition function is stopped, the normal control function can be executed, and each air conditioner 11 can generate a cooling capacity corresponding to the increased amount of heat generation.

[0043] Note that "when the cooling capacity generated by air conditioner 11B increases" means when the increase in the cooling capacity generated by air conditioner 11B exceeds a predetermined increase amount, based on the cooling capacity of air conditioner 11B when the thermo-off prohibition function is executed in air conditioner 11A.

[0044] Specifically, for example, if the drive frequency of compressor 12 of air conditioner 11B when the thermo-off prohibition function is executed in air conditioner 11A is taken as the reference frequency, then "the time when the difference between the drive frequency of compressor 12 of air conditioner 11B and the reference frequency becomes larger than a predetermined value" corresponds to "the time when the cooling capacity generated by air conditioner 11B increases."

[0045] In addition, after the thermo-off prohibition function has started to be executed in air conditioner 11A, when the cooling capacity generated in air conditioner 11B due to the normal control function executed in air conditioner 11B reaches a predetermined lower limit, the thermo-off prohibition function executed in air conditioner 11A is stopped.

[0046] Specifically, after the thermo-off prohibition function starts to be executed in air conditioner 11A, when the drive frequency of compressor 12 of air conditioner 11B reaches the lower limit rotation speed due to the normal control function executed in air conditioner 11B, the thermo-off prohibition function executed in air conditioner 11A stops.

[0047] The reason for this is that when the thermo-off prohibition function is being executed in air conditioner 11A and the cooling capacity generated by air conditioner 11B reaches its lower limit, there is a high possibility that the amount of heat generated in the server room has decreased significantly.

[0048] Therefore, in this case, if the thermo-off prohibition function is stopped, the thermo-off function is executed, preventing an increase in power consumption of the air conditioning system 1 and preventing overcooling of the server room.

[0049] As described above, if the number of times the thermo-off function is executed in air conditioner 11B exceeds a predetermined number of times within a predetermined time period and the drive frequency of compressor 12 of air conditioner 11A is higher than the minimum frequency, execution of the thermo-off function in air conditioner 11B is prohibited.

[0050] Then, after air conditioner 11B starts executing the thermo-off prohibition function, when the cooling capacity generated by air conditioner 11A increases due to the normal control function executed by air conditioner 11A, or when the cooling capacity generated by air conditioner 11A due to the normal control function executed by air conditioner 11A reaches a lower limit value, the thermo-off prohibition function executed by air conditioner 11B stops.

[0051] The thermo-off prohibition function is realized by cooperation between the control unit 16 and the integrated control unit 10. The integrated control unit 10 is configured with a microcomputer having a CPU, ROM, RAM, etc., and is capable of communicating with each control unit 16. Hereinafter, the control unit 16 and the integrated control unit 10 are collectively referred to as the control device.

[0052] Then, software stored in a non-volatile storage unit such as a ROM is executed by the CPU, and a command is issued to the control unit 16 of the corresponding air conditioner 11 to execute the thermo-off prohibition function or to stop the thermo-off prohibition function.

[0053] Specifically, the thermo-off prohibition function is controlled as shown in Fig. 2. That is, when the air conditioning system 1 starts up, the control device executes the normal control function.

[0054] Then, when the thermo-off function is executed, the control device determines whether "in any of the air conditioners, the number of times the thermo-off function has been executed within a specified period of time exceeds a specified number of times, and the cooling capacity of the other air conditioners is greater than a lower limit value," in other words, whether "the thermo-off prohibition condition has been met" (S1).

[0055] If the thermo-off prohibition condition is met (S1: YES), the control device executes the thermo-off prohibition function (S3). Next, the control device judges whether the cooling capacity of the other air conditioners has increased after the execution of the thermo-off prohibition function started (S5), and if it is judged that the cooling capacity of the other air conditioners has increased (S5: YES), the control device stops the thermo-off prohibition function (S7).

[0056] If it is determined that the cooling capacity of the other air conditioners has not increased (S5: NO), the control device determines whether the cooling capacity of the other air conditioners has reached its lower limit after the start of execution of the thermo-off prohibition function (S9). If it is determined that the cooling capacity of the other air conditioners has reached its lower limit (S9: YES), the control device stops the thermo-off prohibition function (S11).

[0057] <3. Features of the Air Conditioning System According to the Present Embodiment> For example, when the thermo-off prohibition function is executed for the air conditioner 11A, the cooling capacity generated by the air conditioner 11A is maintained at the time when the thermo-off prohibition function was executed.

[0058] For this reason, if the amount of heat generated in the server room is constant, the cooling capacity generated by the air conditioner 11B will gradually decrease due to the normal control function executed by the air conditioner 11B. Therefore, the cooling capacities generated by the multiple air conditioners 11A and 11B can be leveled out.

[0059] (Other embodiments) In the above embodiment, an example of the air conditioning system according to the present disclosure is applied to an air conditioning system that conditions the air in a server room. However, the present disclosure is not limited thereto. That is, the present disclosure can be applied to air conditioning in rooms other than a server room, for example.

[0060] The heat exchanger of the air conditioning system 1 according to the above embodiment is a low-pressure side heat exchanger of a vapor compression refrigerator, that is, an evaporator. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, an air conditioning system that generates cold energy by circulating cold water cooled by an evaporator through the heat exchanger.

[0061] The air conditioning system according to the above embodiment is a cooling device that utilizes cold heat. However, the present disclosure is not limited to this. That is, the present disclosure is also applicable to, for example, a heating device that utilizes hot heat.

[0062] The normal control function according to the above embodiment is the suction priority control function. However, the present disclosure is not limited to this. That is, the disclosure may be configured such that the normal control function is executed by the blowing priority control function. Note that, in the blowing priority control function, the cold or hot heat is controlled so that the blowing temperature To becomes the set temperature, and the second blower 15f is controlled to increase or decrease in accordance with the rotation speed of the compressor 12.

[0063] In the above embodiment, each air conditioner 11 is provided with a control unit 16. However, the present disclosure is not limited to this. That is, the present disclosure may be configured, for example, such that the control unit 16 of each air conditioner 11 is eliminated and the integrated control unit 10 directly controls each air conditioner 11.

[0064] In the above-described embodiment, after the thermo-off prohibition function has started to be executed, the thermo-off prohibition function is stopped when the cooling capacity generated in the other air conditioner increases due to the normal control function being executed in the other air conditioner, or when the cooling capacity generated in the other air conditioner due to the normal control function being executed in the other air conditioner reaches a lower limit value.

[0065] However, the present disclosure is not limited to this. That is, the disclosure may be configured such that the thermo-off prohibition function is stopped when a predetermined time has elapsed after the start of execution of the thermo-off prohibition function, or when the temperature rise of the intake temperature Ti or the discharge temperature To of the air conditioner for which the thermo-off prohibition function is being executed exceeds a predetermined degree of rise.

[0066] In the above embodiment, the thermo-off function is executed when the state in which the stop condition is satisfied exceeds a predetermined time. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that the thermo-off function is executed when, for example, the suction temperature Ti becomes equal to or lower than the thermo-off temperature Tc, or when the rotation speed of the compressor 12 becomes equal to or lower than the lower limit rotation speed.

[0067] The air conditioning system according to the embodiment described above is configured with two air conditioners. However, the present disclosure is not limited to this. That is, the present disclosure may be configured with, for example, three or more air conditioners.

[0068] Furthermore, the present disclosure is not limited to the above-mentioned embodiments as long as it is consistent with the gist of the disclosure described in the above-mentioned embodiments. Therefore, the present disclosure may be a configuration in which at least two of the above-mentioned embodiments are combined, or a configuration in which any of the components illustrated or the components described with reference numerals in the above-mentioned embodiments are eliminated. [Explanation of symbols]

[0069] 1. Air conditioning system 10... Integrated control unit 11…Air conditioner 11A…Air conditioner 12… Compressor 13… Condenser 14… Pressure reducer 15… Evaporator 16... Control section S1... Intake temperature sensor S2: Air outlet temperature sensor

Claims

1. a first air conditioner that draws in air from within a room, cools the air, and then supplies the cooled air to the room; a second air conditioner that draws in air from the room, cools the air, and then supplies the cooled air to the room; a first temperature sensor that detects a temperature of air before being cooled by the first air conditioner or a temperature of air after being cooled by the first air conditioner; a second temperature sensor that detects a temperature of the air before being cooled by the second air conditioner or a temperature of the air after being cooled by the second air conditioner; a control device capable of controlling a cooling capacity generated by the first air conditioner (hereinafter referred to as a first cooling capacity) and a cooling capacity generated by the second air conditioner (hereinafter referred to as a second cooling capacity), and capable of executing first air conditioner control, second air conditioner control, and thermo-off prohibition control; The first air conditioner control is a control that controls the first cooling capacity within a predetermined range so that the temperature detected by the first temperature sensor (hereinafter referred to as the first temperature) becomes a preset temperature (hereinafter referred to as the first set temperature), and is capable of stopping the generation of the first cooling capacity to set the first temperature to the first set temperature (hereinafter referred to as the first thermo-off control), The second air conditioner control is a control capable of controlling the second cooling capacity within a predetermined range so that the temperature detected by the second temperature sensor (hereinafter referred to as the second temperature) becomes a preset temperature (hereinafter referred to as the second set temperature), and stopping the generation of the second cooling capacity to make the second temperature the second set temperature (hereinafter referred to as the second thermo-off control), The thermo-off prohibition control is a control for prohibiting the execution of the first thermo-off when the number of times the first thermo-off is executed exceeds a predetermined number of times within a predetermined time and the second cooling capacity is greater than a predetermined lower limit value. The air conditioning system.

2. The air conditioning system according to claim 1 , wherein the control device stops the thermo-off prohibition control when the second cooling capacity is increased by the execution of the second air conditioner control after the execution of the thermo-off prohibition control has started.

3. The air conditioning system according to claim 1 or 2, wherein the control device stops the thermo-off prohibition control when, after starting execution of the thermo-off prohibition control, the second cooling capacity reaches a predetermined lower limit value due to execution of the second air conditioner control.

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