JP2007093117A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently secure the supercooling degree of a liquid refrigerant even in a great load change, keep discharge pressure optimum, and control a blower for a condenser even if a temperature detector or a pressure detector is malfunctioned because of a failure. <P>SOLUTION: A supercooling heat exchanger 3 is provided between a liquid receiver 5 and an expansion valve 6. The rotating speed of the blower 14 is controlled by a fan controller 201 so that pressure is converged to target discharge pressure predetermined depending on a value detected by an outside air temperature detector 105. The target discharge pressure is automatically changed depending on the average operating capacity of compressors 1a, 1b, so that the refrigerating device can be operated by consistently optimum discharge pressure. When the outside air temperature detector or the discharge pressure detector 102 is malfunctioned, the rotating speed of the blower is controlled depending on an operating current in the compressor or the average operating capacity of the compressor to enable continuous operation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus including a fan controller that controls the rotation speed of a condenser blower.

  As a refrigeration apparatus provided with a fan controller for controlling the rotation speed of a conventional condenser blower, there is known a refrigeration apparatus in which the air volume of a blower is controlled by a condensing temperature and an outside air temperature as shown in Patent Document 1. Yes.

JP 2002-147875 A

  Since the load fluctuation of the low-pressure side equipment connected to the refrigeration apparatus is large and frequent, the suction pressure varies greatly accordingly. An inverter refrigerator that drives the compressor by an inverter or a multi refrigerator that has a plurality of compressors frequently changes the operating capacity up and down because the operating capacity is changed by the suction pressure. As the operating capacity moves up and down, the discharge pressure of the refrigeration system also fluctuates. Therefore, when the operating capacity and the discharge pressure decrease due to a sudden decrease in the load, the fan is condensated by controlling the rotational speed. Try to keep the temperature constant. However, when the change in the discharge pressure is large, a sufficient degree of supercooling of the liquid refrigerant from the liquid receiver cannot be ensured, and flash gas may be generated. When flash gas is generated, the refrigeration capacity of the refrigeration apparatus is not stable, and the liquid injection control performed for cooling the motor of the compressor does not function normally. In addition, since the condensing temperature to be kept constant is not varied by the operating capacity, the target condensing temperature is not always optimal.

  An object of the present invention is to obtain a refrigeration apparatus that can sufficiently secure the degree of supercooling of a liquid refrigerant even with a large load fluctuation and can maintain an optimum discharge pressure.

  Another object of the present invention is to provide a refrigeration apparatus that makes it possible to control a condenser blower even when a temperature detector or a pressure detector becomes abnormal due to a failure or the like.

  In order to achieve the above object, a first feature of the present invention is that a refrigeration cycle having an inverter compressor or a plurality of compressors having a variable driving frequency and having a condenser, a liquid receiver, an expansion valve, and an evaporator. A discharge pressure detector that detects the discharge pressure of the compressor, an intake pressure detector that detects the intake pressure, an outside air temperature detector that detects the outside air temperature, and a rotation of the blower that sends cooling air to the condenser A refrigerating apparatus comprising: a fan controller that controls a number; and a control unit that determines a driving frequency of the inverter compressor or an operating number of the plurality of compressors based on a detection value of the suction pressure detector. A heat exchanger for further cooling the liquid refrigerant from the liquid receiver is provided between the expansion valve and the expansion valve, and the rotational speed control of the blower by the fan controller is predetermined according to the detection value of the outside air temperature detector. Is a function to control so as to converge to the target discharge pressure, further, it is to have a target discharge pressure changing means which is adapted to automatically change the target discharge pressure by an average operation capacity of the compressor.

  A second feature of the present invention is a refrigeration cycle including an inverter compressor having a variable driving frequency or a plurality of compressors and having a condenser, a receiver, an expansion valve, and an evaporator, and discharge of the compressor A discharge pressure detector for detecting the pressure, an intake pressure detector for detecting the intake pressure, an outside air temperature detector for detecting the outside air temperature, and a fan controller for controlling the rotational speed of the blower that sends cooling air to the condenser; In the refrigeration apparatus comprising control means for determining the drive frequency of the inverter compressor or the number of operating compressors based on the detection value of the suction pressure detector, between the receiver and the expansion valve A heat exchanger for further cooling the liquid refrigerant from the liquid receiver is provided, and the rotation speed control of the blower by the fan controller is adjusted to a target discharge pressure that is predetermined according to the detection value of the outside air temperature detector. And the target discharge pressure is shifted upward when the outside air temperature detected by the outside air temperature detector becomes a low outside air condition equal to or lower than a preset temperature. The object is to have a control means for controlling the rotational speed to be small.

  A third feature of the present invention is that a refrigeration cycle having a compressor, a condenser, a receiver, an expansion valve, and an evaporator, a discharge pressure detector for detecting the discharge pressure of the compressor, and suction into the compressor The rotation speed of the suction pressure detector for detecting pressure, the outside air temperature detector for detecting the outside air temperature, and the blower for sending cooling air to the condenser is controlled by the detected values of the discharge pressure detector and the outside air temperature detector. In the refrigeration apparatus having a fan controller, when the current detector that detects the operating current of the compressor and the outside air temperature detector or the discharge pressure detector become abnormal, detection by the compressor operating current detector And a control means for controlling the rotational speed of the blower based on the value.

  According to a fourth aspect of the present invention, there is provided a refrigeration cycle including an inverter compressor having a variable driving frequency or a plurality of compressors and having a condenser, a liquid receiver, an expansion valve and an evaporator, and discharge of the compressor. The discharge pressure detector that detects the pressure, the suction pressure detector that detects the suction pressure to the compressor, the outside air temperature detector that detects the outside air temperature, and the rotational speed of the blower that sends cooling air to the condenser In the refrigeration apparatus having a fan controller that is controlled by the detection values of the discharge pressure detector and the outside air temperature detector, the means for calculating the average operating capacity of the compressor, and the outside air temperature detector or the discharge pressure detector is abnormal. When it becomes, it has in the control means which controls the rotation speed of the said air blower with the average operating capacity of the said compressor.

  According to the present invention, the heat exchanger for further cooling the liquid refrigerant from the liquid receiver is provided between the liquid receiver and the expansion valve, and the rotational speed control of the blower by the fan controller is based on the detection value of the outside air temperature detector. Since it has a function to control to converge to a predetermined target discharge pressure in response to this, and further has a target discharge pressure changing means that automatically changes the target discharge pressure according to the average operating capacity of the compressor, Even if the load fluctuates greatly and the compressor driving frequency and the number of compressors operating fluctuate greatly, the degree of supercooling of the liquid refrigerant can be secured sufficiently, and the target discharge pressure is optimized by the compressor operating capacity. Since it can be changed automatically, it can also save energy.

  In addition, when the outside air temperature detected by the outside air temperature detector becomes a low outside air condition that is equal to or lower than a preset temperature, the control means for controlling the target discharge pressure to be shifted upward and the blower rotation speed to be reduced. If the outside air temperature is lowered at night or the like, the target discharge pressure is shifted upward, so that the rotation speed of the blower can be reduced and the noise can be reduced.

  A current detector for detecting the operating current of the compressor, and a control means for controlling the rotational speed of the blower based on a detection value of the current detector when an outside air temperature detector or a discharge pressure detector becomes abnormal. With this, even if the temperature detector or the pressure detector becomes abnormal due to a failure or the like, the rotation speed of the blower can be controlled by the compressor operating current, so that the operation can be continued without stopping the refrigeration apparatus.

  Means for calculating the average operating capacity of the compressor and control means for controlling the rotational speed of the blower by the average operating capacity of the compressor when the outside air temperature detector or the discharge pressure detector becomes abnormal Even if the temperature detector or the pressure detector becomes abnormal, the rotation speed of the blower can be controlled by the average operating capacity of the compressor, so that the operation of the refrigeration apparatus can be continued.

FIG. 1 is a system diagram showing the configuration of the refrigeration cycle unit.
In FIG. 1, I is an air-cooled integrated refrigeration apparatus, II is a low-pressure side device, and these are connected at pipe connection parts 15 and 16 to constitute a refrigeration cycle. Reference numerals 1a and 1b denote scroll compressors of a constant speed system driven by a commercial power source or a variable capacity system using an inverter. A condenser 2 is provided downstream of the scroll compressors 1a and 1b. 3 is a supercooler (heat exchanger), and is configured to be integrated with the condenser 2.

  The refrigerant gas discharged from the scroll compressor 1 is cooled and condensed by the condenser 2 and the blower 14, and the condensed liquid refrigerant is stored in the liquid receiver 5, and the liquid refrigerant having a dryness of 0 from the liquid receiver 5. Only the supercooler 3 is guided.

  The supercooled liquid refrigerant passes through the dryer 9 and the sight glass 8, evaporates in the low-pressure apparatus II constituted by the electromagnetic valve 7, the expansion valve 6, the evaporator 4, and the like, and becomes gas refrigerant again. Thereafter, the gas passes through the accumulator 13 and is sucked into the compressors 1a and 1b.

  A working space that is an intermediate pressure of the liquid refrigerant pipe downstream of the subcooler 3 and the scroll compressor 1 (a sealed working space formed by the orbiting scroll and the fixed scroll, and the suction pressure and the discharge pressure) Is connected by a liquid injection pipe 10. The liquid injection pipe 10 is provided with a pressure reducing device 11 such as an electronic expansion valve or a capillary tube in order to control the amount of liquid injection. The liquid injection is performed in order to keep the discharge gas temperature of the scroll compressors 1a and 1b at a temperature lower than the allowable value, and by injecting liquid refrigerant into the working space of the intermediate pressure of the scroll compressors 1a and 1b. The discharge gas is cooled.

  In this embodiment, the liquid injection pipe 10 connects the liquid refrigerant pipe downstream of the supercooler 3 and the scroll compressor 1, but connects the inside of the liquid receiver 5 and the scroll compressor. You may do it.

  In the low pressure device II in which the solenoid valve 7, the expansion valve 6 and the evaporator 4 are arranged, an internal temperature thermostat 301 that operates when the internal temperature of the low pressure device II becomes equal to or higher than a predetermined temperature, An electromagnetic valve 7 that opens and closes according to the operation of the internal temperature thermostat 301 is provided. Here, the electromagnetic valve 7 is disposed upstream of the expansion valve 6 in the refrigeration cycle.

Next, the rotational speed control of the blower 14 in the above embodiment will be described with reference to FIGS.
FIG. 2 is an example of a control diagram for determining a target discharge pressure value with respect to the outside air temperature. A target discharge pressure value with respect to the outside air temperature as shown in FIG. 2 is input to the fan controller 201 in advance, and the target discharge pressure value is obtained from the temperature detected by the outside air temperature thermistor (outside air temperature detector) 105, and the discharge pressure is obtained. If the actual operating discharge pressure detected by the sensor (discharge pressure detector) 102 is higher than the target value, the blower rotation speed is increased to bring the discharge pressure closer to the target, and if lower than the target value, the fan rotation speed is decreased to decrease the discharge pressure. The blower rotation speed control is performed so as to bring the pressure closer to the target, and the cycle is stabilized by keeping the discharge pressure constant. In this embodiment, the subcooler 3 provided on the downstream side of the liquid receiver 5 can sufficiently secure the degree of supercooling of the liquid refrigerant, and the operating capacity and the discharge pressure are reduced due to the sudden decrease in the load. It is possible to prevent the flash gas from being generated even when the pressure drops.

  Further, the present embodiment is provided with a control function (target discharge pressure changing means) for automatically changing the target discharge pressure according to the average operating capacity of the compressor. That is, an inverter refrigerator equipped with an inverter compressor whose drive frequency is variable, or a multi-chiller equipped with a plurality of compressors has an operating capacity depending on the load of the low-pressure side equipment at that time even at the same outside air temperature. Are very different. Therefore, if the target discharge pressure value obtained from the outside air temperature is constant, it cannot always be said to be optimal. Therefore, a control means (target discharge pressure changing means) is provided that calculates the average operating capacity of the refrigerator for a certain period of time and automatically shifts the target discharge pressure value downward when this is small. As a result, a sufficient degree of supercooling of the liquid refrigerant can be ensured, and the discharge pressure can be stabilized at a low level, thereby saving energy.

  In addition, when the outside air temperature becomes a low outside air condition that is equal to or lower than a preset temperature, the control unit (target discharge pressure changing unit) controls the target discharge pressure to shift upward, thereby rotating the fan. The number can be reduced. Since the refrigerator is operated for 24 hours, it is necessary to lower the noise level at night. Therefore, when the outside air temperature falls below a preset temperature assuming nighttime, noise can be reduced by shifting the target discharge pressure upward and lowering the rotational speed of the blower. Note that the upward shift of the target discharge pressure for the purpose of reducing noise can be shifted not by the outside air temperature but also by an input signal from the outside.

FIG. 3 shows an example in which the target discharge pressure value is determined according to the operating current or the average operating capacity. (A) is an example of a control diagram for determining the target discharge pressure value according to the operating current. It is an example of the control diagram which determines a target discharge pressure value according to an average operating capacity.
If the outside air temperature detector 105 or the discharge pressure detector 102 breaks down and becomes abnormal, the target discharge pressure cannot be obtained, and it becomes difficult to control the rotational speed of the blower. In this case, conventionally, the refrigeration apparatus is stopped immediately, and the operation of the refrigeration apparatus cannot be continued. Even if the outside air temperature detector or the discharge pressure detector breaks down, it is important to enable continuous operation of the blower rotation speed by another method without stopping the refrigeration apparatus. In this embodiment, when the outside air temperature detector or the discharge pressure detector fails, the target discharge pressure value can be held according to the operating current or the average operating capacity, as shown in FIG. 3 (a) or (b). Thus, a control means for controlling the rotational speed of the blower is provided.

  That is, as shown in FIG. 3A, the fan rotation speed is controlled by the current value detected by the current sensor (current detector) that detects the compressor operating current. Thereby, the target discharge pressure value can be controlled. This function can be applied not only to a refrigeration apparatus having a capacity control function such as an inverter refrigerator or a multi-chiller but also to a refrigeration apparatus having no capacity control function. Moreover, since it can apply irrespective of the presence or absence of the supercooler 3, it becomes an effective function in continuing the driving | operation of a freezing apparatus.

  Moreover, as shown in FIG.3 (b), it is also possible to control a fan rotation speed according to the average operating capacity of a compressor. In other words, those that can derive the average operating capacity of a compressor, such as an inverter refrigerator or a multi-chiller, can control the rotation speed of the fan even when a sensor such as an outside air temperature detector or a discharge pressure detector fails due to this average operating capacity. Can continue.

  Note that the blower rotation speed control as shown in FIG. 3 can be similarly performed when the outside air temperature detector or the discharge pressure detector causes a detection deviation. For example, if the discharge pressure detector 102 causes a detection error and can only detect a value lower than the normal discharge pressure, the blower rotation speed must be increased, but the detected discharge pressure is low. Therefore, the number of rotations does not increase, and the refrigeration apparatus is abnormally stopped by the high pressure shut-off device attached to protect the refrigeration apparatus. In order to avoid this, in this embodiment, when the compressor operating current or the average operating capacity of the compressor exceeds a predetermined value, the blower air volume is set to the full speed regardless of the detected value by the discharge pressure detector. If the function is provided, the operation can be continued without stopping abnormally.

  The function of continuing the rotation speed control of the blower based on the compressor operation current or the average operation capacity of the compressor when the sensor is abnormal is to provide a liquid refrigerant temperature sensor and perform the rotation speed control of the blower according to the detected value. The same applies to the refrigeration apparatus.

The systematic diagram which shows the refrigerating-cycle structure of one Example of this invention. The control figure (diagram) which shows an example which determines the target discharge pressure value with respect to outside temperature. The control figure (diagram) which shows the example which determines a target discharge pressure value with the operating current or average operating capacity of a compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS I ... Air-cooling integrated refrigerating device, II ... Low pressure side apparatus, 1a, 1b ... Compressor, 2 ... Condenser, 3 ... Supercooler (heat exchanger), 4 ... Evaporator, 5 ... Liquid receiver, 6 ... Expansion valve, 7 ... solenoid valve, 8 ... sight glass, 9 ... dryer, 10 ... liquid injection piping, 11 ... pressure reducing device, 12 ... solenoid valve, 13 ... accumulator, 14 ... blower, 15, 16 ... pipe connection, 101 ... suction pressure sensor (suction pressure detector), 102 ... discharge pressure sensor (discharge pressure detector), 103 ... suction gas temperature thermistor (suction gas temperature detector), 104 ... discharge gas temperature thermistor (discharge gas temperature detector) , 105 ... Outside temperature thermistor (outside temperature detector), 201 ... Fan controller, 301 ... Inside temperature thermostat.

Claims (4)

A refrigeration cycle comprising an inverter compressor having a variable driving frequency or a plurality of compressors and having a condenser, a liquid receiver, an expansion valve and an evaporator, and a discharge pressure detector for detecting the discharge pressure of the compressor A suction pressure detector for detecting the suction pressure, an outside air temperature detector for detecting the outside air temperature, a fan controller for controlling the rotational speed of a blower that sends cooling air to the condenser, and a detection value of the suction pressure detector In the refrigeration apparatus comprising control means for determining the drive frequency of the inverter compressor or the number of operating compressors of the plurality of compressors,
A heat exchanger for further cooling the liquid refrigerant from the liquid receiver is provided between the liquid receiver and the expansion valve,
The fan speed control by the fan controller has a function of controlling to converge to a predetermined target discharge pressure according to the detection value of the outside air temperature detector,
The refrigeration apparatus further comprising target discharge pressure changing means for automatically changing the target discharge pressure according to an average operating capacity of the compressor. A refrigeration cycle comprising an inverter compressor having a variable driving frequency or a plurality of compressors and having a condenser, a liquid receiver, an expansion valve and an evaporator, and a discharge pressure detector for detecting the discharge pressure of the compressor A suction pressure detector for detecting the suction pressure, an outside air temperature detector for detecting the outside air temperature, a fan controller for controlling the rotational speed of a blower that sends cooling air to the condenser, and a detection value of the suction pressure detector In the refrigeration apparatus comprising control means for determining the drive frequency of the inverter compressor or the number of operating compressors of the plurality of compressors,
A heat exchanger for further cooling the liquid refrigerant from the liquid receiver is provided between the liquid receiver and the expansion valve,
The fan speed control by the fan controller has a function of controlling to converge to a predetermined target discharge pressure according to the detection value of the outside air temperature detector,
Further, when the outside air temperature detected by the outside air temperature detector becomes a low outside air condition equal to or lower than a preset temperature, the target discharge pressure is shifted upward, and the blower rotational speed is reduced. A refrigeration apparatus comprising control means. A refrigeration cycle having a compressor, a condenser, a liquid receiver, an expansion valve and an evaporator; a discharge pressure detector for detecting the discharge pressure of the compressor; and a suction pressure detector for detecting the suction pressure to the compressor; In the refrigeration apparatus comprising an outside air temperature detector for detecting the outside air temperature, and a fan controller for controlling the number of rotations of the blower that sends cooling air to the condenser with the detection values of the discharge pressure detector and the outside air temperature detector,
A current detector for detecting an operating current of the compressor;
Control means for controlling the rotational speed of the blower on the basis of a value detected by the compressor operating current detector when the outside air temperature detector or the discharge pressure detector becomes abnormal. apparatus. A refrigeration cycle comprising an inverter compressor having a variable driving frequency or a plurality of compressors and having a condenser, a liquid receiver, an expansion valve and an evaporator, and a discharge pressure detector for detecting the discharge pressure of the compressor A suction pressure detector for detecting a suction pressure to the compressor, an outside air temperature detector for detecting an outside air temperature, and a rotation speed of a blower for sending cooling air to the condenser, the discharge pressure detector and the outside air temperature detector. In a refrigeration apparatus equipped with a fan controller that is controlled by the detected value of
Means for calculating an average operating capacity of the compressor;
And a control means for controlling the rotational speed of the blower according to an average operating capacity of the compressor when the outside air temperature detector or the discharge pressure detector becomes abnormal.

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