JP2007225260A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device capable of preventing dew condensation of a liquid pipe more easily in comparison with large-scale construction such as applying thermal insulation treatment to the liquid pipe, when adding supercooling to the liquid pipe of the refrigerating cycle device to increase its cooling capacity. <P>SOLUTION: The refrigerating cycle device is provided with a first coolant circulation circuit connecting a first compressor 1, a first condenser 2, a first expansion valve 3 and a first evaporator 4 in order. It is provided with a cooling device 5 cooling a liquid coolant flowing from the first condenser 2 to the first expansion valve 3, a liquid pipe temperature sensor 6 detecting a temperature of the liquid pipe 15 sending the coolant cooled by the cooling device 5 to the first expansion valve 3, an ambient temperature sensor 7 detecting an ambient temperature of the liquid pipe 15, and a controller 8 controlling a cooling rate of the cooling device 5 on the basis of each detected value of the liquid pipe temperature sensor 6 and the ambient temperature sensor 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus such as a refrigeration apparatus or an air conditioner.

  In a conventional apparatus using a refrigeration cycle, as a means for increasing the cooling capacity, a method of providing an auxiliary refrigerant circuit for the main refrigerant circuit and adding supercooling to the liquid pipe of the main refrigerant circuit is known. (For example, see Patent Document 1).

Japanese Patent No. 3376844 (FIG. 1 etc.)

  As described above, when supercooling is added to the liquid pipe of the main refrigerant circuit, the cooling or refrigeration capacity is increased by increasing the amount of supercooling, but the temperature of the liquid pipe is lower than the ambient temperature. Condensation is likely to occur on the surface. When condensation occurs, mold or the like propagates on the back of the ceiling, and in some cases, water leakage from the ceiling occurs. Therefore, it is necessary to insulate the liquid pipe. However, in convenience stores and supermarkets where refrigeration cycle devices are widely used, the refrigerant circuit liquid pipes of the refrigeration cycle devices are often placed on the ceiling or the like, and the length is about 100 m from the store. In some cases, the heat insulation treatment is not easy and there is a problem such as an increase in construction costs. In addition, in a store where construction has already been completed, adding heat insulation treatment to piping such as the back of the ceiling has problems such as poor workability and a lot of time and cost for the construction.

  The present invention has been made to solve the above-described problems, and in the case where supercooling that increases the cooling capacity is added to the liquid pipe constituting the refrigerant circuit of the refrigeration cycle apparatus, the liquid pipe is insulated. It is an object of the present invention to provide a refrigeration cycle apparatus that can more easily prevent dew condensation of the liquid pipe without performing a large-scale construction such as processing.

The refrigeration cycle apparatus of the present invention is a refrigeration cycle apparatus including a first refrigerant circulation circuit in which a first compressor, a first condenser, a first decompression device, and a first evaporator are connected in order, A cooling device that cools the liquid refrigerant flowing from one condenser to the first pressure reducing device, and a pipe that detects, as a first detection value, a temperature of a refrigerant pipe that sends the refrigerant cooled by the cooling device to the first pressure reducing device. Temperature detection means; ambient temperature detection means for detecting an ambient temperature of a refrigerant pipe that sends the refrigerant cooled by the cooling device to the first decompression device as a second detection value; and the first and second detection values. And a controller for controlling the cooling amount of the cooling device.
The controller further includes ambient humidity detection means for detecting ambient humidity of a refrigerant pipe that sends the refrigerant cooled by the cooling device to the first decompression device as a third detection value, and the controller includes the first and first controllers. The cooling amount of the cooling device is controlled based on the second and third detection values.

According to the refrigeration cycle apparatus of the present invention, the controller controls the cooling operation of the cooling device by the controller so that the detection value of the pipe temperature detection means does not become lower than the detection value of the ambient temperature detection means. The cooling capacity can be enhanced while preventing the occurrence of condensation in the liquid pipes constituting the circulation circuit.
Also, the dew point temperature is obtained from the detected values of the ambient temperature detecting means and the ambient humidity detecting means, and the cooling operation of the cooling device is controlled by the controller so that the detected value of the pipe temperature detecting means is not lower than the dew point temperature. Thus, it is possible to enhance the cooling capacity while preventing the occurrence of dew condensation in the liquid pipe constituting the first refrigerant circulation circuit.

Embodiment 1 FIG.
1 is a diagram showing a schematic configuration of a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. In this refrigeration cycle apparatus, a first refrigerant circulation circuit in which a first compressor 1, a first condenser 2, a first expansion valve 3 as a pressure reducing device, and a first evaporator 4 are connected in order by a pipe as a main refrigerant circuit. A circuit (main refrigerant circuit) is provided.

  A cooling device 5 is disposed between the first condenser 2 and the first expansion valve 3 for cooling the refrigerant flowing therebetween. Since the high-pressure liquid refrigerant compressed by the first compressor 1 and liquefied by the first condenser 2 passes between the first condenser 2 and the first expansion valve 3 in the first refrigerant circulation circuit. In the specification, the pipe between the first condenser 2 and the first expansion valve 3 is also referred to as a liquid pipe 15.

Further, between the cooling device 5 and the first expansion valve 3, a liquid pipe temperature sensor 6 as a pipe temperature detecting means for detecting the pipe temperature of that part (temperature of the liquid pipe 15), and the ambient temperature of that part. An ambient temperature sensor 7 as an ambient temperature detection means for detecting, and an ambient humidity sensor 9 as an ambient humidity detection means for detecting the ambient humidity of the portion are provided. The ambient humidity sensor 9 is used in the second embodiment to be described later, and may not be in the first embodiment.
Furthermore, a controller 8 is provided that takes in the detection values of the liquid pipe temperature sensor 6, the ambient temperature sensor 7, and the ambient humidity sensor 9, and controls the cooling amount of the cooling device 5 based on these values. Here, an example is shown in which one liquid tube temperature sensor 6, one ambient temperature sensor 7, and one ambient humidity sensor 9 are used. However, a plurality of them may be used.

  Next, the operation of the refrigeration cycle apparatus of FIG. 1 will be described. The refrigerant in the first refrigerant circulation circuit is compressed into a high-temperature and high-pressure superheated gas by the first compressor 1, and then heat-exchanged with a medium such as air or water in the first condenser 2. The liquid refrigerant is condensed. The liquid refrigerant that has exited the first condenser 2 is converted into a liquid refrigerant that has been supercooled at high pressure by the cooling device 5. Then, the refrigerant is passed through the first expansion valve 3 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, and the refrigerant is heat-exchanged with surrounding air and water in the first evaporator 4 to generate a low-temperature and low-pressure superheated gas. It will be in a state and will be sucked into the first compressor 1 again.

  As described above, in the refrigeration cycle apparatus, it is possible to increase the capacity of the refrigeration cycle apparatus by adding supercooling to the refrigerant flowing through the liquid pipe 15 by the cooling apparatus 5. However, if the liquid pipe temperature falls below the surrounding dew point due to overcooling of the liquid pipe 15, condensation occurs from the surface of the liquid pipe 15, and the dew condensation water hangs down on the ceiling behind the liquid pipe 15. It will be. In order to avoid this, the following means is employed in the refrigeration cycle apparatus of the first embodiment.

FIG. 2 is a flowchart showing an example of the operation of the controller 8 in the first embodiment. According to this, when the refrigeration cycle apparatus is activated (S1), the controller 8 takes in the detected values of the liquid pipe temperature sensor 6 and the ambient temperature sensor 7 during the operation (S2), and compares these values. (S3). And when the temperature of the liquid pipe | tube 15 is equal to the temperature of the circumference | surroundings, operation is continued as it is, without performing special control with respect to the cooling device 5 (S4-1). On the other hand, when the temperature of the liquid pipe 15 is lower than the surrounding temperature, control is performed so that the operation of the cooling device 5 is stopped or decelerated (S4-2). On the other hand, when the temperature of the liquid pipe 15 is higher than the surrounding temperature, control is performed so that the operation of the cooling device 5 is started or accelerated (S4-3).
In FIG. 2, the determination of the cooling amount control of the cooling device 5 is performed in three cases. However, when the liquid pipe temperature ≦ the ambient temperature, the operation of the cooling device 5 is stopped or decelerated, When the tube temperature> the ambient temperature, the operation of the cooling device 5 may be controlled to start or increase in speed.
In order to avoid hunting of the cooling device 5, as a condition for maintaining the current state,
A tolerance may be given such that ambient temperature <liquid crystal temperature <ambient temperature + α (α is a predetermined temperature).

  According to the refrigeration cycle apparatus of the first embodiment controlled as described above, it is possible to ensure supercooling without causing condensation in the liquid pipe 15. For this reason, it is possible to prevent mold and the like from propagating on the back of the ceiling and water leakage from the ceiling. In addition, since the liquid pipe 15 can be supercooled within a range where condensation does not occur, a large-scale work such as a heat insulation treatment is not required for the liquid pipe disposed on the ceiling or the like, and the installation cost of the apparatus is not required. Can be made inexpensive. Furthermore, the supercooling cooling device 5 can be easily applied to a refrigeration cycle device in an existing store where piping has already been installed.

Embodiment 2. FIG.
In the second embodiment, the dew point temperature is determined or calculated from the temperature and humidity around the liquid pipe 15, the dew point temperature is compared with the liquid pipe temperature, and the cooling device 5 is controlled based on the result. It is a thing.
FIG. 3 is a flowchart showing an example of the operation of the controller 8 in the second embodiment. According to this, when the refrigeration cycle apparatus is activated (S11), the controller 8 takes in the detected values of the liquid pipe temperature sensor 6, the ambient temperature sensor 7, and the ambient humidity sensor 9 during the operation (S12). Then, the dew point temperature is determined or calculated from the detected values of the ambient temperature sensor 7 and the ambient humidity sensor 9. The dew point temperature can be obtained by obtaining the water vapor pressure from the air temperature and relative humidity and obtaining the temperature at which the water vapor pressure is the saturated water vapor pressure. Therefore, the dew point temperature can be obtained by preparing the calculation formula in advance and substituting the detection values of the ambient temperature sensor 7 and the ambient humidity sensor 9 into the calculation formula.

Subsequently, the dew point temperature calculated in S13 is compared with the liquid tube temperature detected by the liquid tube temperature sensor 6 (S14). Here, when the temperature of the liquid pipe 15 is equal to the dew point temperature, no special control is performed on the cooling device 5, and the operation is continued as it is (S15-1). On the other hand, when the temperature of the liquid pipe 15 is lower than the dew point temperature, control is performed to stop or decelerate the operation of the cooling device 5 (S15-2). On the other hand, when the temperature of the liquid pipe 15 is higher than the dew point temperature, control is performed so as to start or increase the operation of the cooling device 5 (S15-3).
In FIG. 3, the determination of the cooling amount control of the cooling device 5 is divided into three cases. However, when the liquid pipe temperature ≦ dew point temperature, the operation of the cooling device 5 is stopped or decelerated, When the tube temperature> the dew point temperature, the operation of the cooling device 5 may be started or accelerated.
In order to avoid hunting of the cooling device 5, as a condition for maintaining the current state,
The tolerance may be given as follows: dew point temperature <fluid temperature <dew point temperature + α (α is a predetermined temperature).

  Also in the case of the second embodiment, the same effect as in the first embodiment can be achieved. Since the dew point temperature around the liquid pipe 15 is necessarily lower than the ambient outside air temperature, the control of the cooling device according to the second embodiment causes more subcooling of the liquid pipe 15 than the control according to the first embodiment. It is possible to increase the capacity by supercooling.

Embodiment 3 FIG.
Here, a specific example of the cooling device 5 that cools the liquid pipe 15 will be described. The cooling device 5 is not limited to the one described below, and other devices (for example, a cooling device using ice or water) that can cool the liquid refrigerant flowing inside the liquid pipe 15 are appropriately used. It's okay.

  4 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to Embodiment 3 of the present invention. In FIG. 4, the configuration of the first refrigerant circulation circuit is the same as in the first and second embodiments. On the other hand, what was used as the cooling device 5 in the first and second embodiments is here the second compressor 10, the second condenser 11, the second expansion valve 12 as the second decompression device, and the refrigerant. It is comprised from the refrigerating cycle which has the 2nd refrigerant circulation circuit to which the heat exchanger 13 which heat-exchanges with a refrigerant | coolant was connected in order. The heat exchanger 13 includes a refrigerant flowing between the first condenser 2 and the first expansion valve 3 in the first refrigerant circulation circuit, and the second expansion valve 12 and the second compressor 10 in the second refrigerant circulation circuit. It arrange | positions so that heat exchange may be performed between the refrigerant | coolants which flow through.

  Next, the supercooling operation using the second refrigerant circulation circuit of the refrigeration cycle apparatus of FIG. 4 will be described. In the second refrigerant circulation circuit, the refrigerant is compressed into a high-temperature and high-pressure superheated gas by the second compressor 10, and then heat-exchanged with a medium such as air or water in the second condenser 11, whereby high-temperature and high-pressure is performed. The liquid refrigerant is condensed. Then, by passing the liquid refrigerant through the second expansion valve 12, it becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant state and enters the low-pressure side flow path of the heat exchanger 13. The low-temperature and low-pressure gas-liquid two-phase refrigerant exchanges heat with the liquid refrigerant in the first refrigerant circulation circuit that flows through the high-pressure side passage of the heat exchanger 13 to become a low-temperature and low-pressure superheated gas state. 10 is inhaled.

As described above, the liquid refrigerant flowing through the liquid pipe 15 of the first refrigerant circulation circuit is cooled by the heat exchanger 13 of the second refrigerant circulation circuit, and the supercooling is ensured.
In the third embodiment, the cooling amount control for preventing condensation of the liquid pipe 15 is performed in the same manner as in the first and second embodiments. In that case, in the third embodiment, the controller 8 controls the operating frequency of the second compressor 10 or controls the start and stop of the second compressor 10, thereby cooling by the second refrigerant circulation circuit. The amount can be easily controlled.

By the way, when operating both the first refrigerant circuit and the second refrigerant circuit, if the evaporation temperature of the second refrigerant circuit is higher than the evaporation temperature of the first refrigerant circuit, only the first refrigerant circuit is operated. Compared with the case where it is carrying out, it can always perform efficient operation.
Therefore, the controller 8 monitors the refrigerant evaporation temperatures of the first refrigerant circulation circuit and the second refrigerant circulation circuit, so that the evaporation temperature of the second refrigerant circulation circuit is always higher than the evaporation temperature of the first refrigerant circulation circuit. When the controller 8 is configured to control the operation state of the first compressor 1 and the second compressor 10, the operation efficiency of the refrigeration cycle apparatus is improved.

  In each of the above-described embodiments, when the controller 8 restricts the operation of the cooling device 5 to prevent condensation of the liquid pipe 15, the operation of the cooling device 5 is restricted on the use side of the refrigeration cycle device. It is preferable to give a display or warning so that it can be seen. Further, when such a display or warning is issued, for example, the first compressor 1 is controlled so as to increase its operation so as to compensate for the lack of capacity of the refrigeration cycle apparatus. Good.

It is a refrigerant circuit figure of the refrigerating cycle device concerning Embodiments 1 and 2 of this invention. 3 is a flowchart showing the operation of the controller in the first embodiment. 10 is a flowchart showing the operation of the controller in the second embodiment. It is a refrigerant circuit figure of the refrigerating cycle device concerning Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st compressor, 2nd 1st condenser, 3rd 1st expansion valve, 4th 1st evaporator, 5 cooling device, 6 liquid pipe temperature sensor, 7 ambient temperature sensor, 8 controller, 9 ambient humidity sensor, 10th 2 compressors, 11 second condenser, 12 second expansion valve, 13 heat exchanger, 15 liquid pipe.

Claims (8)

A refrigeration cycle apparatus including a first refrigerant circulation circuit in which a first compressor, a first condenser, a first decompression device, and a first evaporator are connected in order,
A cooling device for cooling the liquid refrigerant flowing from the first condenser to the first decompression device;
A pipe temperature detecting means for detecting, as a first detection value, a temperature of a refrigerant pipe that sends the refrigerant cooled by the cooling device to the first pressure reducing device;
Ambient temperature detection means for detecting the ambient temperature of the refrigerant pipe that sends the refrigerant cooled by the cooling device to the first decompression device as a second detection value;
A refrigeration cycle apparatus comprising: a controller that controls a cooling amount of the cooling device based on the first and second detection values.   The refrigeration cycle apparatus according to claim 1, wherein the controller controls a cooling operation of the cooling device so that the first detection value does not become lower than the second detection value. Ambient humidity detection means for detecting the ambient humidity of the refrigerant pipe that sends the refrigerant cooled by the cooling device to the first decompression device as a third detection value,
The refrigeration cycle apparatus according to claim 1, wherein the controller controls a cooling amount of the cooling device based on the first, second, and third detection values.   The controller determines a dew point temperature from the second detection value and the third detection value, and controls a cooling operation of the cooling device so that the first detection value does not become lower than the dew point temperature. The refrigeration cycle apparatus according to claim 3, wherein the refrigeration cycle apparatus is provided. The cooling device has a second refrigerant circuit in which a second compressor, a second condenser, a second decompression device, and a heat exchanger that performs heat exchange between the refrigerant and the refrigerant are connected in order,
The heat exchanger includes a refrigerant flowing between the first condenser of the first refrigerant circulation circuit and the first decompression device, the second decompression device and the second compressor of the second refrigerant circulation circuit. It arrange | positions so that heat exchange may be performed between the refrigerant | coolants which flow between between.   The refrigeration cycle apparatus according to claim 5, wherein the cooling amount control of the cooling device by the controller controls an operating frequency of the second compressor.   6. The refrigeration cycle apparatus according to claim 5, wherein the cooling amount control of the cooling device by the controller controls starting and stopping of the second compressor. The refrigeration cycle apparatus according to claim 5, wherein the controller is controlled such that an evaporation temperature of the second refrigerant circulation circuit is higher than an evaporation temperature of the first refrigerant circulation circuit.

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