Refrigeration cycle, air conditioning system, and program

Abstract

[Problem] To provide a refrigeration cycle, an air conditioning system, and a program capable of improving air conditioning efficiency regardless of the use environment. [Solution] A refrigeration cycle comprises a controller that adjusts a control parameter that affects air conditioning efficiency (COP) calculated from air conditioning capacity and power consumption of the refrigeration cycle. The controller adjusts the control parameter, on the basis of an air conditioning efficiency change amount (ΔCOP) calculated from air conditioning efficiency (COP) during a first period and air conditioning efficiency (COP) during a second period after the first period, and a sensor value change amount calculated from a sensor value affected by a change in the control parameter during the first period and a sensor value during the second period, so that the air conditioning efficiency (COP) improves further than the air conditioning efficiency (COP) during the second period.

Description

Refrigeration cycle, air conditioning system and program

[0001] The present disclosure relates to a refrigeration cycle, an air conditioning system, and a program.

[0002] Air conditioners are used in a variety of situations, depending on the installation environment (e.g., height difference between the indoor and outdoor units, piping length, outdoor temperature), and operating methods with different air conditioning loads. Therefore, it is necessary to operate air conditioners so that they can achieve high air conditioning efficiency in any operating environment.

[0003] Patent Document 1 discloses a method of controlling the compressor and outdoor fan so as to minimize the total power consumption of the air conditioning system, determining the capacity of the air conditioning device from the operating mode and sensor values, and predicting and controlling the outdoor fan rotation speed based on that capacity using past data on the compressor's power consumption and air conditioning load.

[0004] In Patent Document 1, the capacity of the air conditioner is predicted using the air enthalpy method for heating and the compressor curve method for cooling. When the capacity of the air conditioner is predicted to be constant, the outdoor fan speed is determined so that the total power consumption of the compressor and outdoor fan is minimized. The outdoor fan speed is then controlled based on a predetermined table to achieve the fan speed closest to the predicted value. This control makes it possible to reduce power consumption under partial load operation and annual power consumption.

[0005] Patent No. 7191207

[0006] However, the control method described in Patent Document 1 controls the outdoor fan rotation speed based on a predetermined table, and since the power consumption characteristics of the outdoor fan rotation speed and the compressor rotation speed may vary depending on the installation environment and operating method, there is a risk that the control may not be sufficient to minimize the total power consumption depending on the usage conditions. In other words, there is a risk that the air conditioning efficiency of the air conditioner may deteriorate depending on the usage conditions.

[0007] An object of the present disclosure is to provide a refrigeration cycle, an air conditioning system, and a program that can improve air conditioning efficiency regardless of the usage environment.

[0008] The refrigeration cycle of the present disclosure is a refrigeration cycle including an outdoor unit and an indoor unit, and is provided with a controller that adjusts control parameters that affect air conditioning efficiency calculated from the air conditioning capacity and power consumption of the refrigeration cycle, and the controller adjusts the control parameters based on the air conditioning efficiency at a first time and an amount of change in air conditioning efficiency calculated from the air conditioning efficiency at a second time after the first time, a sensor value at the first time that is affected by the change in the control parameters, and an amount of change in sensor value calculated from the sensor value at the second time.

[0009] Fig. 1 is a diagram showing a refrigeration cycle including a refrigerant in one embodiment. Fig. 2 is a diagram showing a hardware arrangement of an air conditioning system in one embodiment. Fig. 3 is a diagram showing an example of a relationship between a discharge pressure target value and air conditioning efficiency. Fig. 4 is a diagram showing an example of a relationship between a discharge pressure target value and air conditioning efficiency. Fig. 5 is a flowchart showing an example of a process. Fig. 6 is a flowchart showing another example of a process.

[0010] An embodiment will be described below with reference to Figures 1 to 6. Figure 1 shows a refrigeration cycle of an air conditioning system according to an embodiment. The exemplary air conditioning system may be embodied as an air conditioning device, and more preferably, may be embodied as a VRF system, a PAC system, a RAC system, a refrigeration system, or the like.

[0011] As shown in Figure 1, the refrigeration cycle is assumed to be implemented in an air conditioning system constructed as a VRF (Building Multi-Air Conditioning) system including an outdoor unit 110 and multiple indoor units (also referred to as "IDUs") 130a, 130b. The multiple indoor units 130a, 130b are cooperatively controlled by a shared outdoor unit 110. The outdoor unit 110 is placed in an outdoor space, and the indoor units 130a, 130b are placed in an indoor space 120 such as an office building or apartment building.

[0012] The outdoor unit 110 controls multiple indoor units 130a, 130b to supply air conditioning to the building space and / or to handle the air conditioning load. The indoor units perform room air conditioning according to the air conditioning load. Although two indoor units 130a, 130b are illustrated in FIG. 1 , the number of indoor units can be selected appropriately depending on the specific air conditioning load in the building. Furthermore, the indoor units 130a, 130b can be located together in one large room, or each indoor unit 130a, 130b can be located in a separate room. Note that the combination of the number of indoor units and the room arrangement is not limited to the illustrated embodiment and can be changed depending on the specific air conditioning load, etc.

[0013] The indoor units 130a, 130b are provided with indoor sensors (also referred to as "IDr") 131a, 131b, respectively. The indoor sensors 131a, 131b are, for example, temperature sensors, and can detect the intake temperature from the indoor units 130a, 130b and the discharge temperature to the indoor units 130a, 130b depending on the locations of the temperature sensors. These temperature values ​​are transmitted to the outdoor unit 110 via transmission lines (not shown) and used to calculate the air conditioning capacity, which will be described later.

[0014] The outdoor unit 110 and each of the indoor units 130a, 130b are connected to each other by piping 140 for circulating the refrigerant. In one embodiment, the outdoor unit 110 and each of the indoor units 130a, 130b are connected in sequence by communication lines to control the air conditioning performance of the indoor units 130a, 130b so as to provide appropriate air conditioning within the building.

[0015] 2 shows the hardware arrangement of an air conditioning system in one embodiment. As shown in FIG. 2, the outdoor unit 110 includes a compressor 115, a heat exchanger 112, and an outdoor fan 113 driven by a fan motor 114.

[0016] The compressor 115 is, for example, a scroll compressor and is capable of compressing the refrigerant. The heat exchanger 112 performs heat exchange of the refrigerant flowing to and from the indoor units 130a, 130b, etc. through the four-way valve 111. The flow paths of the four-way valve 111 are indicated by solid and dotted lines, with the solid lines indicating the flow paths used in the cooling mode and the dotted lines indicating the flow paths used in the heating mode.

[0017] The outdoor fan 113 circulates outside air through the heat exchanger 112 to control the temperature of the heat exchanger 112 in order to improve air conditioning efficiency. The outdoor unit 110 further includes a controller 116 that controls the compressor 115 and the outdoor fan 113, and an inverter (not shown).

[0018] The outdoor unit 110 includes, for example, a discharge pressure sensor (also referred to as "Pd") 119a, a suction pressure sensor (also referred to as "Ps") 119b, a suction temperature sensor (also referred to as "Ts") 119c, and a refrigerant temperature sensor (also referred to as "Ts"). ｌｉｑ The compressor 115 further includes a discharge pressure sensor 119a that detects the discharge pressure of the refrigerant, a suction pressure sensor 119b that detects the suction pressure of the compressor 115, a suction temperature sensor 119c that detects the suction temperature, and a refrigerant temperature sensor 119d that detects the refrigerant temperature at a position adjacent to the heat exchanger 112.

[0019] The outdoor unit 110 is connected to the indoor units 130a and 130b via piping 140, check valves 120a and 120b, expansion valves 132a and 132b, etc. The refrigerant controlled by the outdoor unit 110 is circulated to each of the indoor units 130a and 130b to provide the required air conditioning. In one embodiment, the controller 116 controls the operation of the compressor 115, the outdoor fan 113, etc., as well as the expansion valves 132a and 132b and other components.

[0020] The outdoor unit 110 also includes another expansion valve 121, which adjusts the flow rate of refrigerant returning from the indoor units 130a, 130b, etc., and controls the enthalpy of the refrigerant drawn into the compressor 115.

[0021] The controller 116 is implemented as a controller board on which various electronic components are mounted, and the controller board can be arranged as an electrical module inside the outdoor unit 110. The controller 116 includes functional modules that cooperate with the indoor units 130a, 130b, the fan motor 114, and the compressor 115.

[0022] The controller 116 includes a RAM, a ROM, and a CPU. The RAM is a temporary memory for storing various data and provides a working space for the CPU. The RAM can be implemented as a separate memory, but a register memory integrated into the CPU may be used instead of and / or together with the RAM.

[0023] The ROM is a non-volatile memory that stores various programs and data for carrying out air conditioning processing. The RAM and ROM may be implemented inside the CPU module or may be provided separately from the CPU. The CPU may be implemented, for example, as a microprocessor. Data from the indoor units 130a, 130b, etc., is input into the CPU via a communication line, and the CPU controls the air conditioning system. The CPU also loads and executes various programs for carrying out control.

[0024] The data sent from the indoor units 130a, 130b includes, but is not limited to, various data such as the indoor temperatures of the indoor units 130a, 130b, as well as the intake temperatures and outlet temperatures of the indoor units 130a, 130b. Any data required for control execution can be sent from the indoor units 130a, 130b. The CPU applies various processes to the input data and outputs the results of the processes to various modules including the expansion valves 132a, 132b to control the air conditioning system.

[0025] The controller 116 adjusts control parameters that affect the air conditioning efficiency (also referred to as "COP"), which is calculated from the air conditioning capacity and power consumption of the refrigeration cycle. The air conditioning efficiency is calculated using, for example, the following formula (1).

[0026] In formula (1), q is the air conditioning capacity and P is the power consumption. The air conditioning capacity q is calculated, for example, using formula (2) below. The power consumption P is, for example, the sum of the compressor power, the outdoor fan power, and the indoor fan power. Note that the power consumption P may be the compressor power only, or the compressor power and the outdoor fan power, or the compressor power and the indoor fan power.

[0027] In equation (2), ρ is the air density, and Q is the air flow rate (m ３ / sec), and C ｐ is the specific heat of the intake air (kJ / kg·K), ΔT is the temperature difference between the indoor intake temperature and the indoor outlet temperature, and SHF is the ratio of sensible heat to latent heat. Note that the air conditioning capacity q may be calculated assuming SHF is 1. The air density ρ is estimated, for example, by the following formula (3), and the specific heat C of the intake air is ｐ is estimated by, for example, the following equation (4).

[0028] In equation (3), TiD is the indoor intake temperature (similarly to equation (4)).

[0029]

[0030] The controller 116 adjusts the control parameters based on the air conditioning efficiency change calculated from the air conditioning efficiency at the first time (also referred to as the “previous air conditioning efficiency”) and the air conditioning efficiency at the second time (also referred to as the “current air conditioning efficiency”), and the sensor value change calculated from the sensor value at the first time (also referred to as the “previous sensor value”) and the sensor value at the second time (also referred to as the “current sensor value”), so that the air conditioning efficiency is higher than the air conditioning efficiency at the second time (current air conditioning efficiency). This configuration adjusts the control parameters based on the air conditioning efficiency change and the sensor value change so that the air conditioning efficiency is higher than the air conditioning efficiency at the second time, thereby improving the air conditioning efficiency regardless of the installation environment, operating method, and other usage environments. Repeating this control (e.g., at one-minute or two-minute intervals) allows the air conditioning efficiency to approach its maximum value.

[0031] The second time is a time later than the first time, for example, the current time. The first time is a past time (for example, one minute before the second time). The second time may also be a past time, that is, the "present time" in the present air conditioning efficiency and the present sensor value includes a past time.

[0032] At least the previous air conditioning efficiency is stored in a memory such as a ROM. The air conditioning efficiency change amount is the difference between the previous air conditioning efficiency and the current air conditioning efficiency. Specifically, the air conditioning efficiency change amount is the value obtained by subtracting the previous air conditioning efficiency from the current air conditioning efficiency.

[0033] The sensor value is a value that is affected by changes in the control parameter. If the control parameter increases, the sensor value also increases, and if the control parameter decreases, the sensor value also decreases. At least the previous sensor value is stored in a memory such as a ROM. The sensor value change amount is the difference between the previous sensor value and the current sensor value. Specifically, the sensor value change amount is the value obtained by subtracting the previous sensor value from the current sensor value.

[0034] Preferably, the control parameter is a target discharge pressure of the compressor 115, and the sensor value is a discharge pressure value detected by the discharge pressure sensor 119a. This makes it possible to reduce power consumption and improve air conditioning efficiency by controlling the discharge pressure, which has a large impact on power consumption. When the control parameter is the target discharge pressure, the sensor value may be the frequency of the compressor 115. The control parameter is not limited to the above, and may be a target degree of superheat of the refrigerant on the outlet side of the heat exchanger of the indoor unit 130a (or 130b). When the control parameter is a target degree of superheat in the indoor unit 130a, the sensor value may be, for example, the opening degree or degree of superheat of the expansion valve 132a.

[0035] 3 and 4 are diagrams illustrating the relationship between the target discharge pressure value and the air conditioning efficiency. As shown in Fig. 3, when the change in the discharge pressure value (also referred to as "ΔPd"), which is the sensor value change, is less than 0 (i.e., when the target discharge pressure value at the second time is smaller than the target value at the first time), and the change in the air conditioning efficiency (also referred to as "ΔCOP") is less than 0 (i.e., when the air conditioning efficiency at the second time is smaller than the air conditioning efficiency at the first time), ΔCOP also decreases when the discharge pressure value (target discharge pressure value in the figure) decreases (the circled position in Fig. 3). Therefore, the controller controls the target discharge pressure value so that it is greater than the target value at the second time (by adding a positive adjustment value to the target discharge pressure value). The same applies when ΔPd and ΔCOP are zero.

[0036] Furthermore, when ΔPd is greater than 0 (i.e., when the target discharge pressure value for the second time period is greater than the target value for the first time period) and ΔCOP is greater than 0 (i.e., when the air conditioning efficiency for the second time period is greater than the air conditioning efficiency for the first time period), ΔCOP also increases when the target discharge pressure value increases (the position indicated by the circle in Figure 3), so the controller controls the target discharge pressure value so that it is greater than the target value for the second time period (by adding a positive adjustment value to the target discharge pressure value). These controls make it possible to improve air conditioning efficiency.

[0037] As shown in Fig. 4, when ΔPd is smaller than 0 and ΔCOP is larger than 0, ΔCOP increases when the target discharge pressure value decreases (the position indicated by a circle in Fig. 4), so the controller controls the target discharge pressure value to be smaller than the target value for the second time (by adding a negative adjustment value to the target discharge pressure value). The same applies when ΔPd is 0.

[0038] Furthermore, when ΔPd is greater than 0 and ΔCOP is less than 0, ΔCOP becomes smaller when the target discharge pressure value increases (the position indicated by the circle in FIG. 4), so the controller controls the target discharge pressure value so that it becomes smaller than the target value for the second time (by adding a negative adjustment value to the target discharge pressure value). The same applies when ΔCOP is 0. These controls make it possible to improve air conditioning efficiency. The adjustment values ​​described above are set appropriately depending on factors such as the air conditioning capacity and the type of control parameter.

[0039] As shown in Fig. 2, the controller 116 preferably changes the adjustment value of the control parameter in accordance with the amount of change in air conditioning efficiency. This makes it possible to quickly improve air conditioning efficiency and shorten the time it takes for the air conditioning efficiency to reach near its maximum value. For example, if the amount of change in air conditioning efficiency is greater than the change amount reference value, the controller 116 increases the adjustment value of the control parameter above the adjustment reference value (e.g., twice the adjustment reference value), and if the amount of change in air conditioning efficiency is smaller than the change amount reference value, the controller 116 decreases the adjustment value of the control parameter below the adjustment reference value (e.g., 0.5 times the adjustment reference value). The change amount reference value and the adjustment reference value are set as appropriate depending on the air conditioning capacity, the type of control parameter, and the like.

[0040] Preferably, the sensor values ​​include a first sensor value and a second sensor value, the control parameters include a first control parameter that affects the first sensor value and a second control parameter that affects the second sensor value, and the controller 116 adjusts the first control parameter or the second control parameter. With this configuration, by adjusting the first control parameter or the second control parameter based on the amount of change in air conditioning efficiency and the amount of change in sensor value so that the air conditioning efficiency is improved compared to the second time period, it is possible to improve the air conditioning efficiency regardless of the usage environment, such as the installation environment or the operating method.

[0041] The first sensor value and the second sensor value are sensor values ​​detected by different sensors. The first control parameter and the second control parameter are different control parameters. For example, the first sensor value is a discharge pressure value, the first control parameter is a target discharge pressure value, the second sensor value is an opening degree of an indoor expansion valve, and the second control parameter is a target degree of superheat of refrigerant on an outlet side of the indoor heat exchanger.

[0042] It is preferable that the controller 116 adjusts the first control parameter or the second control parameter, whichever has the greater impact on the air conditioning efficiency. This can increase the rate of improvement in the air conditioning efficiency. For example, the amounts of change in the air conditioning efficiency when the first control parameter and the second control parameter are adjusted are stored in a memory such as a ROM, and the controller 116 adjusts the control parameter that is larger among the stored amounts of change. For example, the controller 116 may adjust the first control parameter when the air conditioning efficiency is low, and adjust the second control parameter when the air conditioning efficiency is high, based on the stored amounts of change.

[0043] It is preferable that the air conditioning capacity be calculated from at least the air density, the air flow rate, the outlet temperature, and the intake temperature. Unlike the commonly used compressor curve method, this configuration is not affected by the refrigerant flow rate, making it possible to accurately calculate the air conditioning capacity and improve the accuracy of calculating the air conditioning efficiency. The compressor curve method calculates the air conditioning capacity from the refrigerant flow rate of the compressor and the refrigerant pressure and enthalpy difference at the indoor unit inlet and outlet. Therefore, if a flow rate error occurs when the compressor starts or stops, the accuracy of the air conditioning capacity calculation may decrease.

[0044] An example of a control method for improving air conditioning efficiency will be described in detail with reference to Fig. 5. Fig. 5 is a flowchart showing an example of processing. This processing is executed by, for example, a CPU.

[0045] In this process, the current value, blowout temperature, suction temperature, etc. at the second time are first acquired as sensor data (sensor values) (S101), and the air conditioning efficiency (COP) at the second time is calculated (for example, using the above formula (1)) (S102). Next, the air conditioning efficiency (COP) at the previous time (first time) is acquired from a memory such as a ROM (S103), and the change in air conditioning efficiency (ΔCOP) is calculated (S104). Next, the discharge pressure (Pd) is acquired as sensor data (sensor values) (S105), and the previous time (first time) discharge pressure (Pd) is acquired from the memory (S106), and the change in discharge pressure (ΔPd) is calculated (S107).

[0046] Next, it is determined whether the change in discharge pressure (ΔPd) is greater than 0 (S108). If the change in discharge pressure (ΔPd) is equal to or less than 0, it is determined whether the change in air conditioning efficiency (ΔCOP) is greater than 0 (S109). If the change in discharge pressure (ΔCOP) is equal to or less than 0, a positive constant (adjustment value) is added to the target discharge pressure value (Pdo) (S110). If the change in discharge pressure (ΔCOP) is greater than 0, a negative constant (adjustment value) is added to the target discharge pressure value (Pdo) (S111). Note that if the change in compressor frequency (ΔHz) is greater than 0.1 Hz, the target discharge pressure value from the previous time (before the first time or a second time different from the first time) may be used. This prevents miscalculation of the target discharge pressure value that may occur when the compressor frequency changes significantly.

[0047] If the amount of change in discharge pressure (ΔPd) is greater than 0 in step S108, it is determined whether the amount of change in air conditioning efficiency (ΔCOP) is greater than 0 (S112). If the amount of change (ΔCOP) is greater than 0, a positive constant (adjustment value) is added to the target discharge pressure value (Pdo) (S113). If the amount of change (ΔCOP) is equal to or less than 0, a negative constant (adjustment value) is added to the target discharge pressure value (Pdo) (S114). This process is preferably repeated, for example, at one-minute or two-minute intervals.

[0048] In the above process, the order of each step may be changed as appropriate. For example, the calculation of ΔCOP (S104) and the calculation of ΔPd (S107) may be changed, or the determination in step S108 and the determination in step S109 (step S112) may be changed. The same applies to the processes described below.

[0049] Next, another example of a control method for improving air conditioning efficiency will be described in detail with reference to Fig. 6. Fig. 6 is a flowchart showing another example of processing. This processing is executed by, for example, a CPU.

[0050] In this process, first, the current value, outlet temperature, suction temperature, etc. at the second time are acquired as sensor data (sensor values) (S201), and the air conditioning efficiency (COP) at the second time is calculated (for example, using the above formula (1)) (S202). Next, the air conditioning efficiency (COP) at the previous time (first time) is acquired from a memory such as a ROM (S203), and the change in air conditioning efficiency (ΔCOP) is calculated (S204). Next, the indoor expansion valve opening (Evi) is acquired as sensor data (sensor values) (S205), and the previous (first time) indoor expansion valve opening (Evi) is acquired from the memory (S206), and the change in the indoor expansion valve opening (ΔEvi) is calculated (S207).

[0051] Next, it is determined whether the amount of change (ΔEvi) in the opening degree of the indoor expansion valve is greater than 0 (S208). If the amount of change (ΔEvi) is equal to or less than 0, it is determined whether the amount of change (ΔCOP) in the air conditioning efficiency is greater than 0 (S209). If the amount of change (ΔCOP) is equal to or less than 0, a positive constant (adjustment value) is added to the target degree of superheat (SHO) of the indoor unit (S210). Then, if the amount of change (ΔCOP) is greater than 0, a negative constant (adjustment value) is added to the target degree of superheat (SHO) of the indoor unit (S211).

[0052] If the change in the opening degree of the indoor expansion valve (ΔEvi) is greater than 0 in S208, it is determined whether the change in the air conditioning efficiency (ΔCOP) is greater than 0 (S212). If the change (ΔCOP) is greater than 0, a positive constant (adjustment value) is added to the target superheat value (SHO) of the indoor unit (S213). If the change (ΔCOP) is equal to or less than 0, a negative constant (adjustment value) is added to the target superheat value (SHO) of the indoor unit (S214). This process is preferably repeated, for example, at one-minute or two-minute intervals.

[0053] The program may be coded in any programming language, such as assembler language, C language, C++ language, or other programming languages ​​adapted for network communication including Python, browser software, etc. In another specific embodiment, the air conditioning system can be implemented as a network system connected through wireless communication between the outdoor unit 110, the indoor units 130a, 130b, and the server, rather than through wired communication lines.

[0054] In yet another embodiment, the controller 116 may be implemented as a separate computer, a so-called server, to manage a large-scale refrigeration cycle, for example, the air conditioning system of a skyscraper or an intelligent city, where the air conditioning demand of a house or building or the like is supplied by the refrigeration cycle of the present invention. In this embodiment, the server may be networked with the indoor unit and the outdoor unit via a wireless transmission network, and the server controls the outdoor unit to control the air conditioning capacity to supply the air conditioning demand.

[0055] [1] As described above, in one embodiment, a refrigeration cycle including the outdoor unit 110 and the indoor unit 130a (and / or 130b) includes a controller 116 that adjusts control parameters that affect the air conditioning efficiency (COP) calculated from the air conditioning capacity (q) and power consumption (P) of the refrigeration cycle, and the controller 116 adjusts the control parameters so that the air conditioning efficiency (COP) is higher than the air conditioning efficiency (COP) at the second time based on the air conditioning efficiency (COP) at a first time and the air conditioning efficiency (COP) at a second time after the first time, a change in air conditioning efficiency (ΔCOP) calculated from the air conditioning efficiency (COP) at a first time and the air conditioning efficiency (COP) at a second time after the first time, and a sensor value change calculated from the sensor value affected by the change in the control parameter at the first time and the sensor value at the second time.

[0056] According to this configuration, by adjusting the control parameters based on the change in air conditioning efficiency (ΔCOP) and the change in sensor value so that the air conditioning efficiency (COP) is improved compared to the second time, it is possible to improve the air conditioning efficiency (COP) regardless of the usage environment, such as the installation environment or operating method.

[0057] [2] In the refrigeration cycle described in the above [1], it is preferable that the control parameter is a discharge pressure target value (Pdo), and the sensor value is a discharge pressure value detected by a discharge pressure sensor Pd.

[0058] According to this configuration, by controlling the discharge pressure, which has a large effect on power consumption, it is possible to reduce power consumption and improve the efficiency of air conditioning (COP).

[0059] [3] In the refrigeration cycle according to the above [1] or [2], it is preferable that the controller 116 changes the adjustment value of the control parameter in accordance with the amount of change in air conditioning efficiency (ΔCOP).

[0060] According to this configuration, the air conditioning efficiency (COP) can be improved in a short time, and the time required for the air conditioning efficiency (COP) to reach near its maximum value can be shortened.

[0061] [4] In the refrigeration cycle according to any one of [1] to [3] above, it is preferable that the sensor values ​​include a first sensor value and a second sensor value, the control parameters include a first control parameter that influences the first sensor value and a second control parameter that influences the second sensor value, and the controller 116 adjusts the first control parameter or the second control parameter.

[0062] According to this configuration, by adjusting the first control parameter or the second control parameter based on the change in air conditioning efficiency (ΔCOP) and the change in sensor value so that the air conditioning efficiency (COP) is improved compared to the second time, it is possible to improve the air conditioning efficiency (COP) regardless of the usage environment, such as the installation environment or operating method.

[0063] [5] In the refrigeration cycle described in [4] above, it is preferable that the controller 116 adjusts the first control parameter or the second control parameter, whichever has a greater influence on the efficiency of air conditioning (COP).

[0064] With this configuration, the improvement rate of the air conditioning efficiency (COP) can be increased.

[0065] [6] In the refrigeration cycle according to any one of the above [1] to [5], it is preferable that the air conditioning capacity (q) is calculated from at least the air density, the air flow rate, the blowing temperature, and the suction temperature.

[0066] With this configuration, unlike the commonly used compressor curve method, it is not affected by the refrigerant flow rate, so it is possible to accurately calculate the air conditioning capacity (q) and improve the accuracy of calculating the air conditioning efficiency (COP).

[0067] [7] In the refrigeration cycle according to any one of the above [1] to [6], it is preferable that the controller 116 determines whether to use the adjustment value of the control parameter calculated last time (at the first time or another time) or the adjustment value of the control parameter calculated at the second time, depending on the amount of change in the compressor frequency.

[0068] With this configuration, it is possible to avoid an error in calculation of the target discharge pressure value that occurs when the compressor frequency changes significantly.

[0069] [8] In an air conditioning system constituting a refrigeration cycle described in any one of [1] to [7] above, it is preferable that at least one indoor unit 130a (and / or 130b) is controlled by at least one outdoor unit 110.

[0070] [9] A program executed by the CPU includes a process for adjusting control parameters that affect the air conditioning efficiency (COP) calculated from the air conditioning capacity (q) and power consumption (P) of the refrigeration cycle, and the process adjusts the control parameters so that the air conditioning efficiency (COP) is improved compared to the air conditioning efficiency (COP) at the second time based on an air conditioning efficiency change (ΔCOP) calculated from the air conditioning efficiency (COP) at a first time and the air conditioning efficiency (COP) at a second time after the first time, and a sensor value affected by the change in the control parameter at the first time and a sensor value change calculated from the sensor value at the second time.

[0071] According to this program, by adjusting the control parameters based on the change in air conditioning efficiency (ΔCOP) and the change in sensor value so that the air conditioning efficiency (COP) is improved compared to the second time, it is possible to improve the air conditioning efficiency (COP) regardless of the usage environment, such as the installation environment or operating method.

[0072] The refrigeration cycle, the air conditioning system, and the program are not limited to the configurations of the above-described embodiments, and are not limited to the above-described effects. Furthermore, the refrigeration cycle, the air conditioning system, and the program may be modified in various ways without departing from the spirit of the present invention. For example, one or more of the configurations, methods, etc. of the various modifications described above may be arbitrarily selected and adopted in the configurations, methods, etc. of the above-described embodiments.

[0073] 110: outdoor unit, 111: four-way valve, 112: heat exchanger, 113: outdoor fan, 114: fan motor, 115: compressor, 116: controller, 119a: discharge pressure sensor, 119b: suction pressure sensor, 119c: suction temperature sensor, 119d: refrigerant temperature sensor, 120: indoor space, 120a: check valve, 120b: check valve, 121: expansion valve, 130a: indoor unit, 130b: indoor unit, 132a: expansion valve, 132b: expansion valve, 140: piping

Claims

1. A refrigeration cycle including an outdoor unit and an indoor unit, comprising a controller that adjusts control parameters that affect air conditioning efficiency calculated from the air conditioning capacity and power consumption of the refrigeration cycle, wherein the controller adjusts the control parameters based on the air conditioning efficiency at a first time and an amount of change in air conditioning efficiency calculated from the air conditioning efficiency at a second time after the first time, a sensor value at the first time that is affected by the change in the control parameters, and an amount of change in sensor value calculated from the sensor value at the second time, so that the air conditioning efficiency is improved compared to the air conditioning efficiency at the second time.

2. The refrigeration cycle according to claim 1, wherein the control parameter is a target discharge pressure value, and the sensor value is a discharge pressure value detected by a discharge pressure sensor.

3. The refrigeration cycle according to claim 1, wherein the controller changes the adjustment value of the control parameter in accordance with the amount of change in the air conditioning efficiency.

4. The refrigeration cycle of claim 1, wherein the sensor values ​​include a first sensor value and a second sensor value, the control parameters include a first control parameter that affects the first sensor value and a second control parameter that affects the second sensor value, and the controller adjusts the first control parameter or the second control parameter.

5. The refrigeration cycle according to claim 4, wherein the controller adjusts one of the first control parameter and the second control parameter, whichever has a greater effect on the air conditioning efficiency.

6. The refrigeration cycle according to claim 1, wherein the air conditioning capacity is calculated from at least air density, air flow rate, outlet temperature, and intake temperature.

7. The refrigeration cycle according to claim 2, wherein the controller determines whether to use the previously calculated adjustment value of the control parameter or the adjustment value of the control parameter calculated at the second time as the adjustment value of the control parameter, depending on the amount of change in the compressor frequency.

8. An air conditioning system comprising the refrigeration cycle according to any one of claims 1 to 7, wherein at least one of the indoor units is controlled by at least one of the outdoor units.

9. A program executed by a CPU, the program including a process for adjusting control parameters that affect air conditioning efficiency calculated from the air conditioning capacity and power consumption of a refrigeration cycle, the process adjusting the control parameters so that the air conditioning efficiency is improved compared to the air conditioning efficiency at the second time based on the air conditioning efficiency at a first time and the amount of change in air conditioning efficiency calculated from the air conditioning efficiency at a second time after the first time, the sensor value at the first time that is affected by the change in the control parameters, and the amount of change in sensor value calculated from the sensor value at the second time.

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