Air conditioning device

Abstract

To disclose one example of air conditioner that can appropriately control an indoor temperature.SOLUTION: When an excessively increasing change amount and an excessively lowering change amount occur within an evaluation time, an air conditioner 1 determines that hunting has occurred and executes feedback control using a suppressing derivative gain smaller than a normal derivative gain. Thus since hunting can be suppressed, an indoor temperature can be controlled appropriately. The evaluation time is a predetermined time longer than a sampling time. A change time is a time shorter than the evaluation time and equal to or longer than the sampling time. The excessively increasing change amount is change amount that is a positive value and of which absolute value is a predetermined value or greater. The excessively lowering change amount is change amount that is a negative value and of which absolute value is a predetermined value or greater.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to air conditioning systems. [Background technology]

[0002] For example, paragraphs 0005 and 0006 of Patent Document 1 state that the control gain is reduced as a means for preventing the secondary refrigerant temperature from overshooting and hunting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-89783 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in a server room, heat generating elements such as information and communication technology devices are installed. The information and communication technology devices have computing units such as CPUs and GPUs, and cooling fans. The cooling fans blow indoor air to the computing units to cool them.

[0005] The air conditioner that cools the server room automatically adjusts its cooling capacity so that the temperature in the server room reaches the set temperature. At this time, if the room temperature detected by the temperature sensor fluctuates significantly, the temperature change trend may not be captured correctly, and the room temperature may not be controlled appropriately.

[0006] In view of the above, the present disclosure discloses an example of an air conditioner capable of appropriately controlling the room temperature. [Means for solving the problem]

[0007] An air conditioner that adjusts the room temperature to a target set temperature (Tt) desirably has at least one of the following configuration requirements, for example.

[0008] That is, the configuration includes a heat source unit (11) that generates cold or hot heat for air conditioning, a temperature sensor (7) that detects the temperature of indoor air, and a capacity control unit (6) that controls the amount of heat supplied to the room. The capacity control unit (6) acquires the temperature detected by the temperature sensor (7) (hereinafter referred to as the measured temperature (Ts)) at predetermined time intervals (hereinafter referred to as the sampling time), and calculates the temperature using the deviation (P) between the measured temperature (Ts) and a set temperature (Tt) and the rate of change (D) of the measured temperature (Ts). The capacity control unit (6) can control the amount of heat supply by PD control or PID control (hereinafter, these are referred to as feedback control) using a normal differential gain (Kd1) and a suppressed differential gain (Kd2) smaller than the normal differential gain (Kd1) as a differential gain used in the feedback control, and further, when an excessive increase or decrease in the amount of change occurs within the evaluation time, the capacity control unit (6) can execute feedback control using the suppressed differential gain (Kd2).

[0009] The evaluation time is a predetermined time that is longer than the sampling time, and the change time is a time that is shorter than the evaluation time and longer than the sampling time.

[0010] The amount of change refers to the difference between the measured temperatures (Ts) acquired at different times among the multiple measured temperatures (Ts) acquired within the evaluation time, when the difference between the different times is the change time.

[0011] The excessive change amount is a positive change amount whose absolute value is equal to or greater than a predetermined value, and the excessive change amount is a negative change amount whose absolute value is equal to or greater than a predetermined value.

[0012] As a result, in the air conditioner, if an excessive increase or decrease in the amount of change occurs within the evaluation time, it is assumed that hunting has occurred, and feedback control using the suppression differential gain (Kd2) is executed. Therefore, since hunting can be suppressed, it is possible to appropriately control the room temperature.

[0013] 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]

[0014] [Figure 1] 1 is a diagram showing an air conditioner according to a first embodiment. [Diagram 2] 4 is a flowchart showing control of the air conditioner according to the first embodiment. [Diagram 3] 1A and 1B are graphs for explaining features of the air conditioner according to the first embodiment. [Figure 4] 10 is a flowchart showing control of an air conditioner according to a second embodiment. [Diagram 5] FIG. 11 is a diagram showing an air conditioner according to a third embodiment. [Figure 6] 10 is a flowchart showing control of an air conditioner according to a third embodiment. [Figure 7] 10 is a graph for explaining features of the air conditioner according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] 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.

[0016] At least one of each of the components or parts described with a reference symbol is provided, unless otherwise specified by "one". In other words, unless otherwise specified by "one", two or more of the components may be provided. The air conditioner disclosed in this disclosure includes at least the components or parts described with a reference symbol, as well as the structural parts shown in the drawings.

[0017] (First embodiment) <1. Air conditioner configuration> In this embodiment, the present disclosure is applied to an air conditioning device that performs air conditioning in a communication equipment room, a server room, etc. (hereinafter, referred to as a server room.) At least one piece of information and communication technology equipment, etc. is installed in the server room.

[0018] The air conditioner 1 shown in Fig. 1 generates cold heat for air conditioning the inside of a server room. The air conditioner 1 is composed of a vapor compression type refrigerator. Specifically, the air conditioner 1 has a compressor 2, a radiator 3, a pressure reducer 4, an evaporator 5, a control unit 6, a temperature sensor 7, etc.

[0019] The compressor 2 compresses the low-pressure gas-phase refrigerant flowing out from the evaporator 5. The radiator 3 cools the high-pressure refrigerant discharged from the compressor 2 and having an increased temperature. In the radiator 3 according to this embodiment, the cooled refrigerant is condensed (liquefied).

[0020] The pressure reducer 4 reduces the pressure of the refrigerant flowing out from the radiator 3. The pressure reducer 4 according to this embodiment is configured with a thermostatic expansion valve. The thermostatic expansion valve automatically adjusts the opening degree (degree of pressure reduction) so that the degree of superheat of the refrigerant at the outlet side of the evaporator 5 becomes a predetermined value.

[0021] The evaporator 5 generates refrigeration capacity, that is, cold heat, by evaporating the liquid-phase refrigerant decompressed by the pressure reducer 4. Specifically, the evaporator 5 is a heat exchanger that exchanges heat between the refrigerant and the air-conditioning air supplied to the server room, thereby cooling the air-conditioning air.

[0022] The indoor fan 5A is a blower for adjusting the volume of conditioned air supplied to the server room. The outdoor fan 3A is a blower for blowing cooling air (outdoor air in this embodiment) to the radiator 3.

[0023] The temperature sensor 7 detects the temperature of the air supplied to the server room. Specifically, the temperature sensor 7 is disposed upstream or downstream of the evaporator 5 to detect the temperature of the air. The control unit 6 acquires the temperature detected by the temperature sensor 7 (hereinafter referred to as the measured temperature Ts) at predetermined time intervals (hereinafter referred to as the sampling time).

[0024] The control unit 6 controls the operation of the compressor 2, the indoor fan 5A, etc. Specifically, the control unit 6 controls the number of revolutions and stopping of the compressor 2 (hereinafter referred to as the operating state of the compressor 2) so that the measured temperature Ts becomes a target temperature (hereinafter referred to as the set temperature Tt). In other words, the control unit 6 functions as a capacity control unit that controls the amount of cold generated by the evaporator 5.

[0025] In addition, the set temperature Tt when the temperature sensor 7 is arranged upstream of the evaporator 5 (hereinafter referred to as suction temperature control) is different from the set temperature Tt when the temperature sensor 7 is arranged downstream of the evaporator 5 (hereinafter referred to as discharge temperature control).

[0026] In the case of suction temperature control, the air volume of the indoor fan 5A is controlled so that the difference between the suction temperature and the blowing temperature becomes a predetermined temperature difference. In the case of blowing temperature control, the air volume of the indoor fan 5A is increased or decreased according to an increase or decrease in the rotation speed of the compressor 2. In this embodiment, the compressor 2 and the indoor fan 5A, etc. are controlled by the suction temperature control.

[0027] The control unit 6 is configured with a microcomputer having at least a CPU, a ROM, a RAM, etc. Software for executing the control of the compressor 2, the indoor fan 5A, etc. is stored in advance in a non-volatile storage unit (not shown) such as a ROM.

[0028] <2. Control of air conditioners (especially compressors)> <Control Overview> The control unit 6 performs PD control (including PD control) or PID control (hereinafter, these are also referred to as feedback control) on the operating state of the compressor 2. Specifically, the control unit 6 determines the operation amount u when changing the rotation speed of the compressor 2, using the deviation P and the rate of change D.

[0029] The deviation P is the difference between the measured temperature Ts and the set temperature Tt. The rate of change D is the rate of change D of the measured temperature Ts. Then, the control unit 6 determines the operation amount u of the compressor 2 using, for example, "u = Kp P + Kd D".

[0030] Kp is a proportional gain. In this embodiment, a predetermined fixed value is always used as the proportional gain in the PD control. Kd is a differential gain. In this embodiment, two types of predetermined differential gains are used in the PD control.

[0031] That is, the control unit 6 according to this embodiment can execute normal control and hunting suppression control as control of the operating state of the compressor 2. The normal control and the hunting suppression control have different values ​​of the derivative gain used to determine the manipulated variable.

[0032] Specifically, the control unit 6 uses a normal differential gain Kd1 as the differential gain during normal control, and uses a suppression differential gain Kd2 as the differential gain during hunting suppression control. The suppression differential gain Kd2 is a value (including 0) smaller than the normal differential gain Kd1. Note that the suppression differential gain Kd2 according to this embodiment is 0.

[0033] When an excessive increase or decrease in the change amount occurs within the evaluation time, the control unit 6 executes hunting suppression control. When the measured temperature Ts detected within the evaluation time becomes lower than the set temperature Tt, the control unit 6 executes normal control.

[0034] The excessive change amount refers to a change amount that is a positive value and the absolute value of the change amount is equal to or greater than a predetermined value A. The excessive change amount refers to a change amount that is a negative value and the absolute value of the change amount is equal to or greater than a predetermined value A.

[0035] The amount of change means (a) "the difference between the measured temperatures Ts acquired at different times among the multiple measured temperatures Ts acquired within the evaluation time, where the difference between the different times is the change time" or (b) "the difference between any one of the multiple measured temperatures Ts acquired at each sampling time within the evaluation time and the measured temperature acquired immediately before that measured temperature".

[0036] The amount of change according to this embodiment is defined as (a) above. The evaluation time is a predetermined time that is longer than the sampling time. The change time is a time that is shorter than the evaluation time and is equal to or longer than the sampling time. In this embodiment, the sampling time is the change time.

[0037] <Control details> 2 is an example showing a control flow of the above-mentioned compressor 2. The control flow starts when a power switch (not shown) of the air conditioner 1 is turned on, and stops when the power switch is turned off.

[0038] When this control flow is started, the control unit 6 calculates the amount of change in the measured temperature Ts (in this embodiment, the suction temperature) and then stores the calculated amount of change (S1). Then, if an excessively high or low change occurs within the evaluation time, the control unit 6 stores the number of occurrences (S2, S3). Then, if an excessive increase or decrease in the amount of change occurs at least once within the evaluation time (S4: YES), the control unit 6 determines whether or not all of the multiple suction temperatures detected within the evaluation time are equal to or higher than the set temperature Tt (S5).

[0039] When all of the multiple suction temperatures detected within the evaluation time are equal to or higher than the set temperature Tt (S5: YES), the control unit 6 executes hunting suppression control. When at least one of the multiple suction temperatures detected within the evaluation time is lower than the set temperature Tt (S5: NO), or when no excessive increase or decrease in the amount of change occurred within the evaluation time (S4: NO), the control unit 6 executes normal control.

[0040] 3. Features of the Air Conditioner According to the Present Invention In the air conditioner 1 according to this embodiment, if an excessive increase or decrease in the change amount occurs within the evaluation time, it is assumed that hunting has occurred, and feedback control using the suppression differential gain Kd2 is executed. Therefore, since hunting can be suppressed, it is possible to appropriately control the room temperature.

[0041] That is, when the compressor 2 is controlled using conventional control, that is, only normal control, even if the measured temperature Ts continues to be higher than the set temperature Tt as shown in FIG. 3A, when hunting occurs, the control unit reduces the compressor capacity, that is, the drive frequency of the compressor 2 (see part a in FIG. 3A).

[0042] In contrast, in the air conditioner 1 according to this embodiment, when an excessive increase or decrease in the amount of change occurs within the evaluation time, the hunting suppression control is executed, so that the controller 6 is prevented from lowering the capacity of the compressor (see part b in FIG. 3B). As a result, it becomes possible to appropriately control the room temperature.

[0043] Second embodiment In the first embodiment, the control unit 6 executes normal control when the measured temperature Ts detected within the evaluation time falls below the set temperature Tt. In contrast, in the present embodiment, as shown in S5A of Fig. 4, when the average value of a plurality of measured temperatures Ts (intake temperature in the present embodiment) within the evaluation time falls below the set temperature Tt, normal control is executed.

[0044] Note that the other points are the same as those in the first embodiment. In Fig. 4, the same components as those in the above-mentioned embodiment are denoted by the same reference numerals as those in the above-mentioned embodiment. Therefore, in this embodiment, the overlapping description is omitted.

[0045] Third embodiment The suppression differential gain Kd2 according to the above embodiment is a predetermined fixed value. In contrast, the suppression differential gain Kd2 according to the above embodiment is determined as a function value having a rate of change of the blown temperature within the evaluation time as a variable.

[0046] That is, the control unit 6 determines the suppression differential gain Kd2 by utilizing the rate of change of the blown temperature within the evaluation time, and executes hunting suppression control (also referred to as suppression feedback control) by using the determined suppression differential gain Kd2.

[0047] For this reason, the air conditioner 1 according to this embodiment is provided with a second temperature sensor 8, as shown in Fig. 5. The second temperature sensor 8 detects the temperature of the air after heat exchange in the evaporator 5. It should be noted that the temperature sensor 7 detects the temperature of the air before heat exchange in the evaporator 5.

[0048] Then, as shown in FIG. 6, if an excessive increase or decrease in the amount of change occurs at least once within the evaluation time (S4: YES), the control unit 6 executes hunting suppression control using the suppression differential gain Kd2 determined using the rate of change of the blown temperature within the evaluation time (S8).

[0049] If no excessive increase or decrease in the change amount occurs within the evaluation time (S4: NO), the control unit 6 executes normal control (also called normal feedback control). Note that the normal control according to this embodiment is PD control or PID control that utilizes the deviation between the suction temperature and a predetermined set temperature Tt and the rate of change of the suction temperature.

[0050] Other than the above, the present embodiment is the same as the first embodiment. In Fig. 6, the same components as those in the above embodiment are denoted by the same reference numerals. Therefore, in this embodiment, the same description is omitted.

[0051] As described above, the hunting suppression control according to this embodiment is PD control or PID control that utilizes the deviation between the suction temperature (temperature detected by the temperature sensor 7) and the set temperature Tt, and the rate of change of the discharge temperature (temperature detected by the second temperature sensor 8), so that the control unit 6 is prevented from lowering the compressor capacity (see part c in FIG. 7). As a result, it is possible to appropriately control the room temperature.

[0052] (Other embodiments) The air conditioner 1 according to the above embodiment is a so-called "package air conditioner" configured with a vapor compression refrigeration machine. However, the present disclosure is not limited to this. That is, the present disclosure is also applicable to an air conditioner that performs cooling or heating by circulating cold water or hot water through a heat exchanger, for example.

[0053] The capacity control unit of the air conditioner controls the amount of cold or hot heat generated in the heat exchanger by controlling the flow rate of cold or hot water circulated through the heat exchanger. Specifically, the capacity control unit controls the amount of cold or hot heat generated in the heat exchanger by controlling the opening degree of a flow control valve.

[0054] In the above embodiment, the value A which is the threshold value of the excessive change amount and the value A which is the threshold value of the excessive change amount are the same value. However, the present disclosure is not limited to this. That is, the present disclosure may be, for example, that the two values ​​are different values.

[0055] In the above-described embodiment, hunting suppression control is executed when (1) an excessive increase or decrease in change amount occurs at least once within the evaluation time and the measured temperature Ts detected within the evaluation time becomes equal to or greater than the set temperature Tt, or (2) an excessive increase or decrease in change amount occurs at least once within the evaluation time and the average value of the measured temperature Ts within the evaluation time becomes equal to or greater than the set temperature Tt.

[0056] However, the present disclosure is not limited thereto. That is, the present disclosure may be configured such that, for example, when an excessively high change amount and an excessively low change amount occur at least once within an evaluation time, hunting suppression control is executed without determining other conditions.

[0057] The air conditioner 1 according to the embodiment described above is a cooling device that utilizes cold heat. However, the present disclosure is not limited to this. In other words, the present disclosure is also applicable to, for example, a heating device that utilizes hot heat.

[0058] 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]

[0059] 1…Air conditioner 2. Compressor 3… Heatsink 3A… Outdoor fan 4… Pressure reducer 5. Evaporator 5A… Indoor fan 6... Control section 7...Temperature sensor

Claims

1. In air conditioning equipment that adjusts room temperature, A heat exchanger that cools or heats air supplied to the room; A temperature sensor for detecting the temperature of air supplied to the room; A capacity control unit for controlling the amount of cold or hot heat generated by the heat exchanger, The capacity control unit acquires the temperature detected by the temperature sensor (hereinafter referred to as the measured temperature) at a predetermined time interval (hereinafter referred to as the sampling time), and is capable of controlling the amount of heat supply by PD control or PID control (hereinafter referred to as feedback control) utilizing the deviation between the measured temperature and a predetermined set temperature and the rate of change of the measured temperature; A predetermined time that is longer than the sampling time is set as an evaluation time, A time period shorter than the evaluation time period and equal to or longer than the sampling time period is set as a change time period, a difference between the measured temperatures acquired at different times among the plurality of measured temperatures acquired within the evaluation time, the difference being the change time between the different times; and The amount of change is a positive value, and an amount of change in which the absolute value of the amount of change is equal to or greater than a predetermined value is defined as an excess amount of change, When the amount of change is a negative value and the absolute value of the amount of change is equal to or greater than a predetermined value, the amount of change is defined as an excessive amount of change. the capability control unit is capable of using a normal differential gain and a suppression differential gain smaller than the normal differential gain as a differential gain used in the feedback control, Furthermore, the capacity control unit is capable of executing the feedback control using the suppression differential gain when the excessive increase and decrease in the amount of change occurs within the evaluation time.

2. In air conditioning equipment that adjusts room temperature, A heat exchanger that cools or heats air supplied to the room; A temperature sensor for detecting the temperature of air supplied to the room; A capacity control unit for controlling the amount of cold or hot heat generated by the heat exchanger, The capacity control unit acquires the temperature detected by the temperature sensor (hereinafter referred to as the measured temperature) at a predetermined time interval (hereinafter referred to as the sampling time), and is capable of controlling the amount of heat supply by PD control or PID control (hereinafter referred to as feedback control) utilizing the deviation between the measured temperature and a predetermined set temperature and the rate of change of the measured temperature; A predetermined time that is longer than the sampling time is set as an evaluation time, a difference between any one of the plurality of measured temperatures acquired at each sampling time within the evaluation time and a measured temperature acquired immediately before the measured temperature is defined as an amount of change; The amount of change is a positive value, and an amount of change in which the absolute value of the amount of change is equal to or greater than a predetermined value is defined as an excess amount of change, When the amount of change is a negative value and the absolute value of the amount of change is equal to or greater than a predetermined value, the amount of change is defined as an excessive amount of change. the capability control unit is capable of using a normal differential gain and a suppression differential gain smaller than the normal differential gain as a differential gain used in the feedback control, Furthermore, the capacity control unit is capable of executing the feedback control using the suppression differential gain when the excessive increase and decrease in the amount of change occurs within the evaluation time.

3. 3. The air conditioner according to claim 1, wherein the capacity control unit is capable of executing the feedback control using the normal differential gain when the measured temperature detected within the evaluation time falls below the set temperature.

4. 3. The air conditioner according to claim 1, wherein the capacity control unit is capable of executing the feedback control using the normal differential gain when an average value of the plurality of measured temperatures within the evaluation time period falls below the set temperature.

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