JP2008249204A - Refrigerating cycle apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle apparatus, improving the capability of a compressor and efficiently cooling a space to be cooled. <P>SOLUTION: This refrigerating cycle apparatus R is constructed by a refrigerating circuit 40 including a compressor 26 and an evaporator 27. The apparatus includes a chamber temperature sensor 38 for detecting the temperature in a display chamber 11 cooled by the evaporator 27 and a control device C for controlling the operating frequency of a compressor motor 26M for driving the compressor 26, wherein the control device C includes a liquid crystal display panel 8 as a means for controlling the operating frequency of the compressor motor 26M by PID control based on a deviation between the target temperature in the display chamber 11 and the temperature in the display chamber 11 detected by the temperature sensor 48, and setting the speed for changing the operating frequency of the compressor motor 26M. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus including a refrigerant circuit including a compressor and an evaporator, and more particularly to operation frequency control of a compressor motor of a compressor.

Conventionally, a refrigeration cycle apparatus forms a predetermined refrigerant circuit by sequentially connecting a compressor, a condenser, an expansion valve as a pressure reducing device, an evaporator, and the like in an annular manner through a pipe, and a predetermined amount is contained in the refrigerant circuit. The refrigerant is enclosed. When the compressor is operated, the refrigerant is compressed into a high-temperature and high-pressure gas state and flows into the condenser. The refrigerant dissipates heat in the condenser and is condensed and liquefied, and then decompressed by an expansion valve and supplied to the evaporator. In the evaporator, the liquid refrigerant after being depressurized evaporates, and at that time, it absorbs heat from the surroundings and exhibits a cooling action. In addition, there exists a cooling storage as shown in patent document 1 as an apparatus provided with the said refrigeration cycle apparatus.
JP 2002-286347 A

  In the cooling storage as described above, the operating frequency of the DC motor of the compressor is controlled by an inverter device. Specifically, in the pull-down operation, the compressor is operated at a predetermined frequency, and as the temperature detected by the internal temperature sensor approaches the set temperature, the operation frequency of the compressor is gradually reduced by the inverter device. ing.

  However, in the operation frequency control of the compressor, since the speed for changing the operation frequency is constant, there is a problem that the operation frequency control according to each of the storage and the showcase in which the refrigeration cycle apparatus is mounted cannot be realized. there were.

  Therefore, when it is mounted on a device having a small capacity of the space to be cooled, there is a problem in that the speed of changing the operating frequency is too high, causing a hunting phenomenon. On the other hand, when mounted on a device having a large capacity of the space to be cooled, there is a problem that followability is poor because the speed of changing the operating frequency is slow.

  Therefore, the present invention has been made to solve the conventional technical problems, and can improve the capacity of the compressor and can efficiently cool the space to be cooled. I will provide a.

  The refrigeration cycle apparatus of the present invention includes a refrigerant circuit including a compressor and an evaporator, and includes a temperature sensor that detects the temperature of a space to be cooled that is cooled by the evaporator, and a compression that drives the compressor. Control means for controlling the operating frequency of the machine motor, the control means operating the compressor motor by PID control based on the deviation between the target temperature of the cooled space and the temperature of the cooled space detected by the temperature sensor. Means is provided for controlling the frequency and setting a speed for changing the operating frequency of the compressor motor.

  According to the present invention, in a refrigeration cycle apparatus including a refrigerant circuit including a compressor and an evaporator, a temperature sensor that detects the temperature of a space to be cooled that is cooled by the evaporator, and a compressor motor that drives the compressor Control means for controlling the operating frequency of the compressor motor, and the control means determines the operating frequency of the compressor motor by PID control based on the deviation between the target temperature of the cooled space and the temperature of the cooled space detected by the temperature sensor. In addition to controlling, by providing means for setting a speed for changing the operating frequency of the compressor motor, the ability of the compressor according to the capacity of the space to be cooled of the model in which the refrigeration cycle apparatus is mounted is exhibited. Is possible.

  As a result, even if the size of the compressor is small, it becomes possible to efficiently cool the cooled space in accordance with the capacity of the other types of cooled space, thereby improving versatility. Is possible.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a showcase 1 according to an embodiment to which the present invention is applied, and FIG. 2 is a vertical side view of the showcase 1 of FIG. The showcase 1 of an Example is an open showcase which has an opening in the front surface installed in stores, such as a convenience store and a supermarket. In the display room 11 for displaying products formed in the showcase 1, a cooling area, a heating area, or both a cooling area and a heating area can be configured, so that the use of cooling / heating is possible. It is supposed to be possible.

  The main body 2 is constituted by a heat insulating wall 3 having a substantially U-shaped cross section that opens to the front surface of the showcase 1 and side plates 4 and 4 attached to both sides thereof. A back panel 6 and a top panel 7 are disposed on the back and top surfaces of the inside of the heat insulating wall 3 with a space therebetween, and the back panel 6 and the top panel 7 and the heat insulating wall 3 are spaced from the back. A rear duct 9 extending upward is formed.

  In addition, a deck pan 10 extending forward is provided at the lower end of the back panel 6, and a display chamber 11 is formed inside the back panel 6, the top panel 7, and the deck pan 10. A lower duct 14 communicating with the rear duct 9 and constituting a part thereof is formed below the deck pan 10.

  The upper end of the rear duct 9 communicates with the upper cool air discharge port 16 positioned at the upper edge of the front opening of the display chamber 11, and the front end of the lower duct 14 is positioned at the lower edge of the front opening of the display chamber 11 and includes a plurality of slits. It communicates with the cold air inlet 17. A cool air circulation blower 19 is disposed in the lower duct 14 below the deck pan 10, and a refrigeration cycle apparatus R is configured in the rear duct 9 behind the display chamber 11 together with a compressor 26 and a condenser 27 described later. An evaporator 15 is provided vertically.

  A plurality of shelves 12 are installed in the display chamber 11, and in this embodiment, four shelves are installed vertically. Each shelf device 12 has a pair of left and right brackets 20 having hook-like claws protruding rearward at the rear end, a shelf board 21 mounted on the bracket 20 and mounted thereon, and a product placement surface of the shelf board 21. And a heating electric heater 22 (shown in FIG. 4) attached to the back side of the heater.

  Then, each shelf device 12 is engaged with the engagement holes of the shelf columns (not shown) attached to both front surfaces of the rear panel 6 in the display chamber 11 so that the rack devices 12 can be engaged and disengaged. It is installed so that the vertical position (height) can be changed inside.

  Further, in FIG. 2, reference numeral 35 denotes a shelf duct member. In the shelf duct member 35, a shelf duct 36 having a shelf lower cool air discharge port 37 that opens obliquely forward and downward is formed at the front end. In addition, a damper member 39 is provided in the shelf duct 36 so as to advance and retract toward the rear duct 9 so as to close the rear duct 9.

  On the other hand, a machine room 25 is formed below the heat insulating wall 3, and a compressor 26, a condenser 27, a condenser blower 28, and the like are installed in the machine room 25, as well as a power source and a control. An electrical box (not shown) that houses the substrate is also provided.

  Here, the refrigerant circuit 40 which comprises the refrigerating-cycle apparatus R in a present Example is demonstrated with reference to the refrigerant circuit figure of FIG. A condenser 27 is connected to the piping 42 on the discharge side of the compressor 26. An expansion valve 44 as a pressure reducing device is connected to the outlet side of the condenser 27 via a pipe 43. The expansion valve 44 is connected to the evaporator 15, and the outlet side of the evaporator 15 is connected to the compressor 26 to constitute an annular refrigeration cycle.

  A back plate 29 made of steel plate is attached to the back of the heat insulating wall 3 with a predetermined distance from the back surface of the heat insulating wall 3, and an exhaust duct is provided between the back plate 29 and the heat insulating wall 3. 30 is configured. The lower end of the exhaust duct 30 opens and communicates with the rear portion of the machine room 25, and the upper end is open above the showcase 1. Therefore, when the condenser blower 28 is operated, the outside air sucked into the machine room 25 passes through the condenser 27 and exchanges heat, and is then blown to the compressor 26 to cool the compressor 26 by air. Then, it is discharged to the outside through the exhaust duct 30.

  A panel 31 closes the front surface of the machine room 25 so that it can be opened and closed. Reference numeral 32 denotes an evaporating dish provided in the lower part of the machine room 25, and drain water (dewed water, defrosted water, etc.) from the evaporator 15 flows in through a drain hose (not shown) and is stored.

  Next, the control device (control means) C in the present embodiment will be described with reference to FIG. The control device C is composed of a general-purpose microcomputer and incorporates a timer 50 as a time limit means, a PID arithmetic processing unit 56, and a storage unit 57. Further, a control panel 47 having various setting switches and a display unit is connected. The various setting switches include an LCD panel (setting means) 8 for arbitrarily setting a model in which the refrigeration cycle apparatus R is mounted as will be described in detail later. Further, an internal temperature sensor 48 for detecting the internal temperature, a shelf sensor 49 for detecting the temperature of each shelf device 12, and the like are connected to the input side of the control device C.

  Here, the in-compartment temperature sensor 48 is provided, for example, on the ceiling in the display room 11 of the showcase 1 and detects the in-compartment temperature that is the temperature in the display room 11. The shelf sensor 49 is provided in each shelf device 12 and detects a shelf temperature that is the temperature of each shelf device 12.

  On the other hand, on the output side of the control device C, a compressor motor 26M that drives the compressor 26, an electric heater 22 provided in each shelf device 12, a blower motor 19M that drives the cool air circulation blower 19, and a condenser blower 28 A blower motor 28M, an expansion valve 44, and the like are connected. Here, the compressor motor 26M is connected via the inverter device 41, and thereby the frequency of the power source is changed, and the rotational speed of the compressor motor 26M is changed to thereby compress the refrigerant in the compressor 26. Can be changed. Moreover, the electric heater 22 is connected via the heater control part 51, and, thereby, it is possible to change the energization amount for each electric heater 22 by duty control or the like. Moreover, the blower motor 19M of the blower 19 for cold air circulation is connected via a drive circuit 52 such as a chopper circuit, whereby the rotational speed of the blower motor 19M can be arbitrarily changed. Similarly, the blower motor 28M of the condenser blower 28 is connected via a drive circuit 53 such as a chopper circuit, whereby the rotational speed of the blower motor 28M can be arbitrarily changed.

  The control operation of the showcase 1 will be described with the above configuration. First, based on the input setting by the control panel 47 or the like, the control device C determines whether the entire display room 11 is refrigerated and used as a cooling region or the whole is used as a heating region as a heating region. The damper member 39 provided determines whether the display chamber 11 is to be used in cold / hot conditions where the interior of the display chamber 11 is divided into a cooling region and a heating region.

  When it is determined that the entire display chamber 11 is used as a heating area, the control device C operates the compressor motor 26M, the blower motor 28M of the condenser blower 28, and the blower motor 19M of the cooler circulation blower 19. While stopping, the energization control to the electric heater 22 for each shelf device 12 is executed based on the shelf temperature detected by the shelf sensor 49 provided in each shelf device 12. Specifically, when the shelf temperature detected by the shelf sensor 49 is equal to or lower than the temperature obtained by subtracting the differential temperature from the heating set temperature, the electric heater 22 of the shelf device 12 is energized, and the shelf sensor 49 When the detected shelf temperature is equal to or higher than the temperature obtained by adding the differential temperature to the warming set temperature, energization to the electric heater 22 of the shelf device 12 is stopped. Thereby, the inside of the display chamber 11 on each shelf apparatus 12 and also the inside of the display chamber 11 is maintained at the heating set temperature.

  On the other hand, when it is determined that the entire display chamber 11 is refrigerated and used as a cooling region, the control device C deenergizes all the electric heaters 22 and displays the display chamber (cooled) detected by the internal temperature sensor 48. The cooling operation is executed based on the internal temperature which is the temperature in the space 11.

  That is, when the operation of the compressor 26 is started, the high-temperature and high-pressure gas refrigerant discharged from the piping 42 on the discharge side of the compressor 26 flows out to the condenser 27. Here, since the expansion valve 44 is controlled to be opened and closed by the control device C, the sufficiently condensed and liquefied refrigerant is decompressed by the expansion valve 44 and then flows into the evaporator 15. Then, the refrigerant flowing into the evaporator 15 disposed in the back duct 9 evaporates, takes heat from the surroundings and exhibits a cooling action, and then returns to the compressor 26.

  The cold air exchanged heat with the evaporator 15 is passed through the upper cold air discharge port 16 and the under shelf cold air discharge port 37 of the shelf duct 36 by the cool air circulation blower 19 disposed in the lower duct 14 communicating with the rear duct 9. After being discharged, a part of the cool air circulates in the display chamber 11 to cool the display chamber 11 to a predetermined cooling temperature, and then the lower duct is passed through the cool air suction port 17 located at the lower edge of the front opening of the display chamber 11. Return to 14 Thereby, an air curtain by cold air is formed in the front opening of the display chamber 11, and cold air leakage and outside air intrusion in the display chamber 11 are suppressed.

  Here, the operating frequency of the compressor motor 26M of the compressor 26 is the temperature detected by the internal temperature sensor 48 by the PID arithmetic processing unit 56 provided in the control device C (in the display chamber 11 which is the space to be cooled). PID control based on execution of proportional (P), integral (I), and differential (D) calculations from deviation e between the target cooling set temperature Ts set by the control panel 47 Is executed. Specifically, the PID control arithmetic processing unit 56 calculates a control amount in a direction in which the temperature Tp detected by the internal temperature sensor 48 is reduced in proportion to the difference e between the target cooling set temperature Ts. The integral operation for calculating the control amount in the direction to reduce the operation, the integral value of the deviation e (the value obtained by integrating the deviation e with the cooling set temperature Ts in the time axis direction), and the slope (differential value) of the variation of the deviation e. A differential operation for calculating the control amount in the decreasing direction is performed, and the operating frequency of the compressor motor 26M of the compressor 26 is determined from the control amount obtained by adding these control amounts. The calculation formula is shown below.

Expression Kp × deviation e + Ki × integral value of deviation e + Kd × differential value of deviation e = control amount By controlling the operating frequency of the compressor motor 26M by the inverter device 41 based on the calculated control amount, the display room 11 can be accurately brought close to the target temperature. In this control, the speed at which the operating frequency of the compressor motor 26M is changed is changed according to the setting as described later in detail.

  In addition, when the inside of the display room 11 is divided into a cooling area and a heating area by any shelf device 12 and is used for cooling / heating, the control apparatus C can select either one based on the input setting by the control panel 47 or the like. It is determined whether the upper side of the shelf device 12 is used as a heating region and the lower side is used as a cooling region.

  And the control apparatus C performs cooling operation based on the chamber internal temperature which is the temperature in the display chamber 11 which the chamber internal temperature sensor 44 detects. Also in the cooling operation, similarly to the above, the inside of the display chamber 11 below the shelf device 12 is cooled to a predetermined set temperature.

  Further, the control device C supplies the electric heaters 22 for each of the shelf devices 12 based on the shelf temperature detected by the shelf device 12 and the shelf sensor 49 provided in the shelf device 12 positioned above the shelf device 12. Execute energization control. Thereby, the inside of the display chamber 11 located on the upper side of the shelf device 12 is heated to the heating set temperature.

  Next, details of speed setting control for changing the operating frequency of the compressor motor 26M in each cooling operation as described above will be described with reference to the flowchart of FIG. In order to be able to support a plurality of models in which the refrigeration cycle apparatus R is mounted, the control device C stores a change rate (operation of the operating frequency of the compressor motor 26M in accordance with each model setting in the built-in storage unit 57. The speed at which the frequency is increased and the speed at which the operating frequency is decreased) are stored.

  In this embodiment, the storage unit 57 is configured by an EEPROM which is a nonvolatile memory, and has 10 to 50 model settings. Note that the closer the model setting is to 10, the setting corresponding to the apparatus having a smaller capacity of the cooled space with respect to the capacity of the compressor 26 to be mounted. The closer the model setting is to 50, the higher the capacity of the compressor 26 to be mounted. It is assumed that the setting corresponds to a device having a large capacity of the space to be cooled. Moreover, although the model setting is 10-50, if it is two or more types, the number of model settings will not be limited.

  Therefore, when the refrigeration cycle apparatus R is incorporated into the showcase 1 or at the time of installation, various switches are operated according to the display on the LCD panel 8 provided on the control panel 47 to set the model, which is 10 in this embodiment. Any one of ~ 50 is set.

  Accordingly, the control device C determines whether or not the set model is 10 in step S1, and if it is 10, the process proceeds to step S2 and the model setting 10 stored in the storage unit 57 is obtained. In this embodiment, the speed for increasing the operating frequency of the compressor motor 26M is set to 15 seconds / Hz. Thereafter, the process proceeds to step S3, and similarly, the set value stored in the storage unit 57 and the speed at which the operating frequency of the compressor motor 26M is lowered are set to 20 seconds / Hz. Then, the process proceeds to step S4, and thereafter, the operation frequency control of the compressor motor 26M in the cooling operation as described above is executed based on the set operation frequency change speed of the compressor motor 26M.

  On the other hand, if it is determined in step S1 that the set model is not 10, the control device C determines whether or not the set model is 20 in step S5. Advances to step S6. In step S6, the control device C sets the setting value corresponding to the model setting 20 stored in the storage unit 57, in this embodiment, the speed for increasing the operating frequency of the compressor motor 26M to 15 seconds / Hz. To do. Thereafter, the process proceeds to step S3, and similarly, the set value stored in the storage unit 57 and the speed at which the operating frequency of the compressor motor 26M is lowered are set to 15 seconds / Hz. Then, the process proceeds to step S4, and thereafter, the operation frequency control of the compressor motor 26M in the cooling operation as described above is executed based on the set operation frequency change speed of the compressor motor 26M.

  Similarly, when it is determined in step S5 that the set model is not 20, the control device C proceeds to step S8 and determines whether or not the set model is 30. When the model setting is 30, the process proceeds to step S9, where the control device C sets the setting value corresponding to the model setting 30 stored in the storage unit 57, in this embodiment, the operating frequency of the compressor motor 26M. The rate of increase is set to 10 seconds / Hz. Thereafter, the process proceeds to step S10, and similarly, the set value stored in the storage unit 57 and the speed at which the operating frequency of the compressor motor 26M is lowered are set to 10 seconds / Hz. Then, the process proceeds to step S4, and thereafter, the operation frequency control of the compressor motor 26M in the cooling operation as described above is executed based on the set operation frequency change speed of the compressor motor 26M.

  Similarly, when it is determined in step S8 that the set model is not 30, the control device C proceeds to step S11 and determines whether or not the set model is 40. When the model setting is 40, the process proceeds to step S12, and the control device C sets the setting value corresponding to the model setting 40 stored in the storage unit 57, in this embodiment, the operating frequency of the compressor motor 26M. Set the rate of increase to 5 seconds / Hz. Thereafter, the process proceeds to step S13, and similarly, the set value stored in the storage unit 57 and the speed at which the operating frequency of the compressor motor 26M is lowered are set to 10 seconds / Hz. Then, the process proceeds to step S4, and thereafter, the operation frequency control of the compressor motor 26M in the cooling operation as described above is executed based on the set operation frequency change speed of the compressor motor 26M.

  Similarly, when it is determined in step S11 that the set model is not 40, the control device C proceeds to step S14 and determines whether or not the set model is 50. When the model setting is 50, the process proceeds to step S15, and the control device C sets the setting value corresponding to the model setting 50 stored in the storage unit 57, in this embodiment, the operating frequency of the compressor motor 26M. Set the rate of increase to 1 second / Hz. Thereafter, the process proceeds to step S16, and similarly, the set value stored in the storage unit 57 and the speed at which the operating frequency of the compressor motor 26M is lowered are set to 5 seconds / Hz. Then, the process proceeds to step S4, and thereafter, the operation frequency control of the compressor motor 26M in the cooling operation as described above is executed based on the set operation frequency change speed of the compressor motor 26M.

  As described above, in this embodiment, since it is possible to set the rising speed and the falling speed of the operating frequency of the compressor motor 26M according to the model setting, the operating frequency control of the compressor motor 26M according to the model is performed. It can be realized. Specifically, when the capacity of the space to be cooled is smaller than the capacity of the compressor 26, for example, by setting the model setting to 10, the operating frequency of the compressor motor 26M by the control device C is PID controlled. The speed at which the operating frequency is raised is set to 15 seconds / Hz, and the speed to be lowered is set to 20 seconds / Hz. As a result, even when the capacity of the space to be cooled is relatively small, the occurrence of the hunting phenomenon can be suppressed and temperature control can be realized with high accuracy.

  On the other hand, when the capacity of the space to be cooled is larger than the capacity of the compressor 26, for example, by setting the model setting to 50, the operating frequency when the operating frequency of the compressor motor 26M by the control device C is PID controlled. Is set to 1 second / Hz, and the speed to decrease is set to 5 seconds / Hz. As a result, even when the capacity of the space to be cooled is relatively large, it is possible to improve the followability to the change in the internal temperature, and it is possible to realize temperature control with high accuracy.

  In particular, in this embodiment, since the speed of change in the operating frequency of the compressor motor 26M suitable for each model setting is stored in the storage unit 57 built in the control device C in advance, the model setting operation is performed. It is possible to control by changing the operating frequency of the compressor motor 26M suitable for the model only by performing it, and the ability of the compressor 26 according to the capacity of the space to be cooled can be exhibited.

  As a result, even if the size of the compressor 26 is small, the space to be cooled can be efficiently cooled according to the capacity of the other types of space to be cooled, thereby improving versatility. It becomes possible.

  In the present embodiment, the speed of changing the operating frequency of the compressor motor 26M can be set to a predetermined speed by performing model setting using the LCD panel 8. However, the present invention is not limited to this. The speed at which the operating frequency of the compressor motor 26M is changed, that is, the speed at which the operating frequency is raised and the speed at which it is lowered can be arbitrarily set directly by the LCD panel 8. Accordingly, the speed at which the operating frequency of the compressor motor 26M is changed can be arbitrarily set without being limited to the setting stored in the storage unit 57, and further control according to the model is realized. It becomes possible to do.

  In this embodiment, the speed at which the operating frequency of the compressor motor 26M is changed employs a setting method in which the time interval for changing 1 Hz is set to any one of 15 seconds to 1 second, but is limited to this. Instead, for example, a setting method in which a frequency (for example, 1 Hz to 15 Hz) is changed per unit time (for example, 1 to 15 seconds) may be used.

  In the present embodiment, the showcase 1 is described as an example. However, the present invention is not limited to this, and the present invention is not limited to this, as long as it is a refrigeration cycle apparatus R such as a refrigerator or a prefabricated refrigerator. Becomes effective.

It is a perspective view of a showcase to which the present invention is applied. It is a vertical side view of the showcase of FIG. It is a refrigerant circuit diagram. It is an electrical block diagram of a control apparatus. It is a flowchart which shows the change speed setting of the compressor operating frequency based on model setting.

Explanation of symbols

R Refrigeration cycle device C Control device (control means)
1 Showcase 8 LCD panel (setting means)
9 Rear Duct 11 Display Room 14 Lower Duct 15 Evaporator 16 Upper Cold Air Discharge Port 17 Cold Air Suction Port 19 Cooling Air Circulation Blower 26 Compressor 26M Compressor Motor 27 Condenser 40 Refrigerant Circuit 41 Inverter Device 44 Expansion Valve 48 Internal Temperature Sensor 50 timer 56 PID arithmetic processing unit 57 storage unit

Claims (1)

In the refrigeration cycle apparatus composed of a refrigerant circuit including a compressor and an evaporator,
A temperature sensor that detects the temperature of the space to be cooled that is cooled by the evaporator;
Control means for controlling the operating frequency of a compressor motor that drives the compressor,
The control means controls the operating frequency of the compressor motor by PID control based on the deviation between the target temperature of the cooled space and the temperature of the cooled space detected by the temperature sensor, and the compressor motor A refrigeration cycle apparatus comprising means for setting a speed for changing the operation frequency of the refrigeration cycle.

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