JP2005241050A - Air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning system easy to specify a leaking part. <P>SOLUTION: An outdoor unit 1 is provided with an atmospheric temperature sensor 7 and pressure sensors 8 and 9. The atmospheric air temperature sensor 7 measures temperature of outside of a room wherein an outdoor unit 1 is arranged. The pressure sensors 8 and 9 measure pressure of the refrigerant inside a refrigerant pipe 2 arranged inside the outdoor unit 1. On the basis of a temperature, pressure characteristic showing relation between the temperature in the periphery of the refrigerant and the pressure of the refrigerant, estimated normal pressure of the refrigerant is computed by using the atmospheric temperature detected by the temperature sensor 7 as the peripheral temperature, and leakage of the refrigerant is determined by comparing the real pressure of the refrigerant detected by the pressure sensors 8 and 9 with the computed estimated normal pressure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air conditioning system for circulating a refrigerant in a pipe.

  In recent years, as an air conditioning system used in a building or the like, an individual distributed air conditioning system (multi air conditioner) in which a plurality of indoor units are individually controlled by one outdoor unit has become mainstream.

  FIG. 3 is a diagram for explaining a multi air conditioner. As shown in FIG. 3, in the multi air conditioner, for example, about 1 to 16 indoor units 3 are connected to the refrigerant pipe 2 with respect to one indoor unit 1. To reduce costs and save energy. Each indoor unit 3 is provided with an operation switch 30, and operations such as operation start, stop, and room temperature adjustment are performed from the operation switch 30.

  FIG. 4 is a diagram for explaining a piping path of the refrigerant piping 2 in the multi-air conditioner of FIG. The outdoor unit 1 has a heat exchanger 20 and a compressor 22 that compresses the refrigerant. The outdoor unit 1 has a four-way switching valve (four-way valve) 24 for switching the flow direction of the refrigerant during the cooling operation and the heating operation, and is supplied to each indoor unit 3 via the refrigerant pipe 2. Is circulated.

  Each indoor unit 3 has a heat exchanger 20 and an electronic expansion valve 24. The electronic expansion valve 24 supplies and stops the supply of refrigerant from the outdoor unit 1 to the indoor unit 3 provided with the electronic expansion valve 24, and adiabatically expands the refrigerant as needed when supplying the refrigerant. . Note that the stop valve 4 provided in the refrigerant pipe 2 remains “open” during normal operation or stoppage, and basically separation on the pipe between the outdoor unit 1 and each indoor unit 3 is not performed. I have not been told.

  When the refrigerant gas leaks from at least one of the outdoor unit 1, the refrigerant pipe 2, and the indoor unit 3 in the multi-air conditioner having the piping path shown in FIG. This is performed by detecting a decrease in the discharge gas temperature and an increase in the discharge gas temperature due to an excessive suction steam heating degree. That is, the pressure sensor 8 or 9 detects a pressure abnormality (for example, an internal pressure of 0.1 MPa or less), and the discharge temperature sensor 5 detects an increase in the discharge gas temperature to detect a discharge temperature abnormality. When it was done, the operation of the outdoor unit 1 was stopped.

  However, when the repair is performed by specifying the location where the refrigerant gas has leaked, since a plurality of indoor units 3 are connected, it is difficult to identify the leak location. For example, it is necessary to investigate the refrigerant pipes 2 around the indoor unit 3 one by one in order to identify the leaked part, and there is a problem that a great deal of time is required.

  Then, an object of this invention is to provide the air-conditioning system with which a leak location is easy to identify.

  In order to achieve the above object, an air conditioning system according to a preferred embodiment of the present invention includes a temperature sensor that detects an ambient temperature of a refrigerant and a pressure sensor that detects a refrigerant pressure in an air conditioning system that circulates the refrigerant in a pipe. And calculating an estimated normal pressure of the refrigerant from the ambient temperature detected by the temperature sensor based on a temperature-pressure characteristic indicating a correspondence relationship between the ambient temperature of the refrigerant and the pressure of the refrigerant, and detected by the pressure sensor. The refrigerant leakage is judged from a comparison between the refrigerant pressure and the calculated normal pressure.

  In order to achieve the above object, an air conditioning system according to a preferred aspect of the present invention is an air conditioning system in which a refrigerant is circulated through a pipe between an outdoor unit and the indoor unit. A solenoid valve provided in the pipe, an outdoor temperature sensor that detects an outdoor temperature, an outdoor unit pressure sensor that detects a refrigerant pressure on the outdoor unit side separated by the solenoid valve, And calculating an estimated normal pressure of the refrigerant using the outdoor temperature detected by the outdoor temperature sensor as the ambient temperature based on a temperature-pressure characteristic indicating a correspondence relationship between the ambient temperature of the refrigerant and the pressure of the refrigerant. It is characterized in that leakage of the refrigerant on the outdoor unit side is determined from a comparison between the refrigerant pressure detected by the outdoor pressure sensor and the calculated estimated normal pressure.

  Desirably, it further includes an indoor temperature sensor that detects the indoor temperature, and an indoor unit pressure sensor that detects the pressure of the refrigerant on the indoor unit side separated by the electromagnetic valve, and based on the temperature-pressure characteristics, The estimated normal pressure of the refrigerant is calculated using the indoor temperature detected by the indoor temperature sensor as an ambient temperature, and the indoor unit side is calculated by comparing the refrigerant pressure detected by the indoor unit pressure sensor with the calculated estimated normal pressure. It is characterized by judging the leakage of the refrigerant.

  Moreover, in order to achieve the said objective, the air conditioning system which is a suitable aspect of this invention includes the said outdoor unit in the air conditioning system which circulates a refrigerant | coolant via piping between an outdoor unit and several indoor units. A plurality of solenoid valves provided in the pipe for separating an outdoor unit area and an indoor unit area for each indoor unit including the indoor units, an outdoor temperature sensor for detecting an outdoor temperature, and the plurality An outdoor unit pressure sensor for detecting the pressure of the refrigerant in the outdoor unit area separated by the electromagnetic valve, and a room provided for each of the indoor units in order to detect a room temperature in the room in which the indoor units are arranged. A temperature sensor, and an indoor unit pressure sensor provided for each indoor unit to detect the pressure of the refrigerant in each indoor unit area separated by the plurality of solenoid valves, and the ambient temperature of the refrigerant Based on a temperature-pressure characteristic indicating a correspondence relationship with the refrigerant pressure, an estimated normal pressure of the refrigerant is calculated using the outdoor temperature detected by the outdoor temperature sensor as an ambient temperature, and the refrigerant detected by the outdoor unit pressure sensor is calculated. Based on the comparison between the pressure and the calculated estimated normal pressure, refrigerant leakage in the outdoor unit area is determined, and based on the temperature-pressure characteristics, the indoor temperature detected by the indoor temperature sensor of each indoor unit is used as the ambient temperature. The estimated normal pressure of the indoor unit is calculated, and from the comparison between the refrigerant pressure detected by the indoor unit pressure sensor of the indoor unit and the calculated estimated normal pressure, leakage of the refrigerant in the indoor unit area of the indoor unit is determined. It is characterized by that.

  According to the said structure, since the judgment of a leak is performed for every outdoor unit area and each indoor unit area, specification of a leak location becomes easy. In addition, by providing an electromagnetic valve for each area, the leakage area can be isolated by the electromagnetic valve and the supply of refrigerant to the leakage area can be stopped, so that air pollution due to leakage can be suppressed. It is also possible to isolate only the leaking area and repair only the leaking area while continuing to operate in other areas. Abnormal operation due to refrigerant leakage can be prevented, so that deterioration of refrigerant gas and oil can be prevented.

  According to the present invention, an air conditioning system is provided in which a leak location can be easily identified.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of an air conditioning system according to the present invention, and FIG. 1 is an overall configuration diagram of the air conditioning system of the present embodiment.

  The air conditioning system of this embodiment is a multi air conditioner that controls a plurality of indoor units 3 with a single outdoor unit 1, and is used for air conditioning of buildings, for example. A plurality of indoor units 3 are connected to an outdoor unit 1 installed outside a building or the like via a refrigerant pipe 2. Each indoor unit 3 is installed in each room in the building.

  The outdoor unit 1 has a heat exchanger 20 and a compressor 22 that compresses the refrigerant. Furthermore, the outdoor unit 1 has a four-way switching valve (four-way valve) 24 for switching the flow direction of the refrigerant during the cooling operation and the heating operation, and the refrigerant is supplied to each indoor unit 3 via the refrigerant pipe 2. The cooling operation or the heating operation is executed by circulating the air. The discharge temperature sensor 5 may detect an increase in the discharge gas temperature to determine an abnormality in the discharge temperature, and the operation of the outdoor unit 1 may be stopped when the abnormality is determined as usual. Each indoor unit 3 has a heat exchanger 20 and an electronic expansion valve 24 '. The electronic expansion valve 24 ′ supplies and stops supplying the refrigerant from the outdoor unit 1 to the indoor unit 3 provided with the electronic expansion valve 24 ′, and insulates the refrigerant when supplying the refrigerant as necessary. Inflate.

  The outdoor unit 1 and each indoor unit 3 are each provided with two electromagnetic valves 10. The electromagnetic valve 10 is provided to isolate the outdoor unit 1 and each indoor unit 3 on the piping path. That is, when the two electromagnetic valves 10 provided in the outdoor unit 1 are closed, in FIG. 1, the outdoor unit area on the left side of the two electromagnetic valves 10 (the area surrounded by the dotted line of the outdoor unit 1 in FIG. 1). Is isolated on the piping path. Similarly, when the two electromagnetic valves 10 provided in each indoor unit 3 are closed, the indoor unit area sandwiched between these two electromagnetic valves 10 (the area surrounded by the dotted line of each indoor unit 3 in FIG. 1). Is isolated on the piping path. The solenoid valve 10 is controlled by a control circuit (not shown) and is controlled to open and close as necessary.

  The outdoor unit 1 is further provided with an outside air temperature sensor 7 and pressure sensors 8 and 9. The outside air temperature sensor 7 measures the temperature outside the room where the outdoor unit 1 is disposed, and is attached to, for example, the heat exchanger 20. The pressure sensors 8 and 9 measure the pressure of the refrigerant in the refrigerant pipe 2 arranged in the outdoor unit 1. In the present embodiment, the estimated normal pressure of the refrigerant is calculated based on the temperature-pressure characteristics indicating the correspondence between the ambient temperature of the refrigerant and the pressure of the refrigerant, using the outside air temperature detected by the outside air temperature sensor 7 as the ambient temperature, Leakage of the refrigerant is determined from a comparison between the actual refrigerant pressure detected by the sensors 8 and 9 and the calculated estimated normal pressure. Therefore, a temperature-pressure characteristic indicating a correspondence relationship between the ambient temperature of the refrigerant and the pressure of the refrigerant will be described.

  The refrigerant gas has a characteristic that the pressure changes with a change in the ambient temperature. The relationship between the ambient temperature and the pressure (saturation pressure) is as follows. When the ambient temperature is T (absolute temperature) and the saturation pressure is P (absolute pressure), the temperature-pressure characteristic equation is approximately “log P = ab−T”. It is represented by a and b are constants determined by the type of refrigerant. That is, by setting a and b from the type of refrigerant gas used, the saturation pressure P can be calculated from the measurement result of the ambient temperature (T).

  Therefore, the refrigerant pressure can be calculated from the temperature detected by the outside air temperature sensor 7 of the outdoor unit 1. However, if the refrigerant leaks from the refrigerant pipe 2, the pressure of the refrigerant decreases, and the actual refrigerant pressure does not reach the value obtained by the temperature-pressure characteristic equation. Therefore, the leakage of the refrigerant can be determined from a comparison between the actual refrigerant pressure detected by the pressure sensors 8 and 9 and the pressure obtained from the temperature-pressure characteristic equation. Specifically, the estimated normal pressure Ps obtained from the temperature-pressure characteristic equation is compared with the actual refrigerant pressure P detected by the pressure sensors 8 and 9, and for example, the refrigerant leaks when P ≦ 0.8 Ps. Judge that you are doing. Note that 0.8 multiplied by Ps means that a leakage abnormality is determined based on a 20% decrease in the estimated normal pressure Ps, but if necessary, 10% decrease, 30% decrease, etc. Other criteria may be used.

  Each indoor unit 3 is also provided with a room temperature sensor 6 and a pressure sensor 11. Then, the estimated normal pressure Ps is calculated from the temperature-pressure characteristic equation with the room temperature measured by each room temperature sensor 6 as the ambient temperature, and from the comparison with the actual refrigerant pressure P detected by each pressure sensor 11, The leakage of the refrigerant is determined for each machine 3. Thus, in this embodiment, it is possible to determine the leakage of the refrigerant for each of the outdoor unit 1 and each indoor unit 3. Hereinafter, the detection processing operation will be described.

  FIG. 2 is a flowchart for explaining the refrigerant leak detection processing operation by the air conditioning system of FIG. Hereinafter, the refrigerant leak detection processing operation will be described with reference to FIG. 2 and the parts shown in FIG.

  The control circuit closes the electromagnetic valve 10 when the thermo-off or operation is stopped, and separates the outdoor unit 1 and each indoor unit 3 from each other on the piping path (S201). As a result, the air conditioning system shown in FIG. 1 is separated into an outdoor unit area and a plurality of indoor unit areas. Next, the control circuit detects the numerical values of the outdoor air temperature sensor 7 and the pressure sensors 8 and 9 of the outdoor unit 1, and detects the numerical values of the room temperature sensor 6 and the pressure sensor 11 of each indoor unit 3. (S202).

  Further, the control circuit calculates a saturation pressure (estimated normal pressure) Ps for each of the outdoor unit 1 and the plurality of indoor units 3 from the value of each temperature sensor detected in S202, and the actual pressure of the corresponding pressure sensor. Comparison operation processing with P is executed (S203).

  Then, for each of the outdoor unit 1 and the plurality of indoor units 3, it is determined whether or not P ≦ 0.8Ps is satisfied (S204), and it is determined that the refrigerant is leaking when P ≦ 0.8Ps, The fact that the refrigerant is abnormal is displayed on the operation panel of each device (S205). Of course, the refrigerant abnormality for each area may be displayed in a management room that centrally manages the air conditioning system. The processes of S204 and S205 are executed for each of the outdoor unit 1 and the plurality of indoor units 3, and as a result, refrigerant leakage is determined for each of the outdoor unit area and the plurality of indoor unit areas.

  As described above, in the air conditioning system of the present embodiment, the refrigerant leakage determination is performed for each of the outdoor unit area and the plurality of indoor unit areas. Therefore, it is specified where in the air conditioning system the refrigerant is leaking. It becomes easy. Moreover, since the leaking area is isolated by the electromagnetic valve 10, the amount of refrigerant gas leaked can be minimized to prevent air pollution. Further, the operation of the electromagnetic valve 10 makes it possible to repair the indoor unit area while isolating only the indoor unit area determined to be leaked and operating the air conditioning system quickly. In the repair, the stop valve 4 or the stop valve 12 provided in the refrigerant pipe 2 of FIG. 1 may be used. The stop valve 4 and the stop valve 12 are always opened during normal operation. For example, when replacing a certain indoor unit 3, two stop valves 12 corresponding to the indoor unit 3 are provided. By closing, it becomes possible to remove the indoor unit 3 while operating the air conditioning system.

  As described above, the air conditioning system according to the present embodiment is excellent in terms of maintenance in addition to easily identifying the leak location.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention.

It is a whole lineblock diagram of the air-conditioning system of this embodiment. It is a flowchart for demonstrating the detection processing operation | movement of the refrigerant | coolant leakage by the air conditioning system of this embodiment. It is a figure for demonstrating a multi air conditioner. It is a figure for demonstrating the piping path | route of the refrigerant | coolant piping in a multi air conditioner.

Explanation of symbols

  1 outdoor unit, 2 refrigerant piping, 3 indoor unit, 6 room temperature sensor, 7 outside air temperature sensor, 8, 9, 11 pressure sensor, 10 solenoid valve.

Claims (4)

In an air conditioning system that circulates refrigerant in a pipe,
A temperature sensor for detecting the ambient temperature of the refrigerant;
A pressure sensor for detecting the pressure of the refrigerant;
Have
Based on the temperature-pressure characteristics indicating the correspondence between the ambient temperature of the refrigerant and the refrigerant pressure, the estimated normal pressure of the refrigerant is calculated from the ambient temperature detected by the temperature sensor, and the refrigerant pressure and calculation detected by the pressure sensor are calculated. The refrigerant leakage is judged from the comparison with the estimated normal pressure.
An air conditioning system characterized by that. In the air conditioning system that circulates refrigerant between the outdoor unit and the indoor unit via piping,
A solenoid valve provided in the pipe for separating the outdoor unit and the indoor unit;
An outdoor temperature sensor for detecting the outdoor temperature;
An outdoor unit side pressure sensor for detecting the pressure of the refrigerant on the outdoor unit side separated by the electromagnetic valve;
Have
Based on the temperature-pressure characteristics indicating the correspondence between the ambient temperature of the refrigerant and the pressure of the refrigerant, the outdoor normal pressure sensor calculates the estimated normal pressure of the refrigerant using the outdoor temperature detected by the outdoor temperature sensor as the ambient temperature. The refrigerant leakage on the outdoor unit side is determined from a comparison between the refrigerant pressure detected by the estimated normal pressure calculated,
An air conditioning system characterized by that. The air conditioning system according to claim 2,
An indoor temperature sensor for detecting the indoor temperature;
An indoor unit side pressure sensor for detecting the pressure of the refrigerant on the indoor unit side separated by the electromagnetic valve;
Further comprising
Based on the temperature-pressure characteristics, the estimated normal pressure of the refrigerant is calculated using the indoor temperature detected by the indoor temperature sensor as the ambient temperature, and the estimated normal pressure calculated by the refrigerant pressure detected by the indoor unit-side pressure sensor is calculated. Judging refrigerant leakage on the indoor unit side from comparison with pressure,
An air conditioning system characterized by that. In the air conditioning system that circulates the refrigerant between the outdoor unit and the plurality of indoor units via a pipe,
A plurality of solenoid valves provided in the pipe to separate an outdoor unit area including the outdoor unit and an indoor unit area for each indoor unit including the indoor units;
An outdoor temperature sensor for detecting the outdoor temperature;
An outdoor unit pressure sensor for detecting a refrigerant pressure in an outdoor unit area separated by the plurality of solenoid valves;
An indoor temperature sensor provided for each of the indoor units in order to detect an indoor temperature in a room where the indoor units are disposed;
An indoor unit pressure sensor provided for each indoor unit to detect the pressure of the refrigerant in each indoor unit area separated by the plurality of solenoid valves;
Have
Based on the temperature-pressure characteristics indicating the correspondence between the ambient temperature of the refrigerant and the pressure of the refrigerant, the estimated normal pressure of the refrigerant is calculated using the outdoor temperature detected by the outdoor temperature sensor as the ambient temperature, and the outdoor unit pressure sensor From the comparison between the detected refrigerant pressure and the calculated estimated normal pressure, the leakage of the refrigerant in the outdoor unit area is judged,
Based on the temperature-pressure characteristics, the estimated normal pressure of the refrigerant is calculated using the indoor temperature detected by the indoor temperature sensor of each indoor unit as the ambient temperature, and the refrigerant pressure detected by the indoor unit pressure sensor of the indoor unit From the comparison with the estimated normal pressure calculated, the leakage of the refrigerant in the indoor unit area of the indoor unit is determined.
An air conditioning system characterized by that.

Images