JPH11148745A - Control method of air conditioner - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To allow an outdoor unit to generate cold heat corresponding to a change in a cooling load promptly, and to prevent supercooling of a refrigerant condensed in the outdoor unit. SOLUTION: The refrigerant liquefied in the heat exchanger 2 is supplied to each indoor unit 4.
In an air conditioner configured to be cooled by each indoor unit 4 by the temperature sensor 17.
When the temperature of R is equal to or lower than _ ° C. at which the R-134a is likely to be in a supercooled state, for example, the opening of the fuel adjustment valve 13 is adjusted so that the temperature of R-134a detected by the temperature sensor 17 becomes 7 ° C. When the temperature of the R-134a detected by the temperature sensor 17 is higher than _ ° C. at which there is no concern that the R-134a will be in a supercooled state, the pressure sensor 15
Is detected, the pressure of R-134a is 7 ° C.
The opening of the fuel control valve 13 was adjusted so that the equilibrium pressure when condensing was 7.5 Pa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly, to an air conditioner between an outdoor unit and a plurality of indoor units, all or a majority of which are installed below the outdoor unit.
The present invention relates to control of a device configured to circulate a refrigerant capable of changing phase into two phases of a gas and a liquid mainly by using a specific gravity difference between a liquid and a gas and to be capable of cooling in each indoor unit.

[0002]

2. Description of the Related Art Conventionally, an air conditioner which does not require the power for transporting a phase-changeable refrigerant, that is, a refrigerant whose state changes between liquid and gas by taking in and out latent heat, is shown in FIG. 1, for example. There is such a device. In this device, an outdoor unit 1 functioning as a condenser is installed at a high position in a building, and the outdoor unit 1 and an indoor unit 4 installed in a room to be air-conditioned at a lower position are installed. Liquid phase tube 6 between heat exchanger 5
And the liquid which is radiated and condensed by the outdoor unit 1 is supplied to the heat exchanger 5 of the indoor unit 4 via the liquid phase tube 6 by its own weight, while the heat exchanger of the indoor unit 4 is connected. 5. A gas that has absorbed heat and exchanged heat with indoor air having a high temperature in step 5 to be circulated by returning to the outdoor unit 1 in which the refrigerant is condensed and having a low pressure through the gas phase pipe 7 to condense the refrigerant. Therefore, there is an advantage that a transfer power such as an electric pump is not required, and the running cost can be suppressed. In addition, 8 is a flow control valve and 9 is a blower.

[0003]

In the air conditioner of the above construction, the generation (amount) of cold heat in the outdoor unit for cooling and condensing and liquefying the phase-changeable refrigerant is usually determined by the temperature of the refrigerant. Or, it is controlled based on either the pressure. However, if the generation of the cold heat is controlled based on the temperature, it is not possible to quickly cope with the change in the air conditioning load.If the control is performed based on the pressure, the followability to the load change is improved. There is a problem that even if the refrigerant is in a supercooled state, it cannot be detected.

[0004] In particular, in an outdoor unit having a structure in which cold heat is generated by an absorption-type refrigeration evaporator operated by using oil or gas as a heat source to suppress power consumption in summer when power consumption peaks, supercooling is required. When it becomes a state, the water as the refrigerant of the absorption refrigerator freezes and it becomes impossible to continue operation,
It was necessary to enhance the follow-up of the generation of cold heat with respect to the load fluctuation, and to prevent a supercooling state.

[0005]

In order to solve the above-mentioned problems of the prior art, the present invention provides an outdoor unit functioning as a condenser,
It functions as an evaporator, and circulates the phase-changeable refrigerant mainly by using the specific gravity difference between the liquid phase and the gas phase between a plurality of indoor units, all or a majority of which are installed below the outdoor unit. ,
In the air conditioner configured to be capable of cooling in each indoor unit, the generation of cold heat in the outdoor unit for cooling and condensing the refrigerant is performed when the temperature of the refrigerant condensed in the outdoor unit and flowing is equal to or lower than a predetermined temperature. Based on the temperature, when the temperature is higher than the predetermined temperature, the control method of the air conditioner of the first configuration, wherein the control method based on the pressure of the refrigerant,

[0006] Between the outdoor unit functioning as a condenser and a plurality of indoor units functioning as an evaporator, all or a majority of which are installed below the outdoor unit, the phase-changeable refrigerant is mainly converted into a liquid phase. In the air conditioner configured to be circulated by utilizing the difference in specific gravity from the gas phase and capable of cooling in each indoor unit, the generation of cold heat in the outdoor unit for cooling and condensing the refrigerant is condensed by the outdoor unit and flows. Based on the temperature of the refrigerant when the difference between the saturated temperature converted from the pressure of the refrigerant and the temperature of the refrigerant measured by a thermometer is equal to or greater than a predetermined value, the difference is less than the predetermined value. And a control method of the air conditioner of the second configuration, wherein the control is performed based on the control information.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to FIG.
A description will be given with reference to the air conditioner of FIG. For easy understanding, the same reference numerals in FIG. 1 denote portions having the same functions as those described in FIG.

FIG. 1 shows an example of a configuration of an air conditioner configured to be capable of cooling and heating. Reference numeral 1 denotes an outdoor unit that can selectively generate cold or hot heat, such as an absorption refrigerator. It is installed in a machine room or the like on the roof of a building, for example, and is capable of undergoing a phase change into two phases of gas and liquid sealed in a closed circuit 3 via a heat exchanger 2 piped inside an evaporator, for example. It exchanges heat with refrigerant R-134a, which can easily evaporate when the pressure drops even at low temperatures, for example.

As an absorption refrigerator capable of supplying cold or warm heat from the heat exchanger 2 connected to the evaporator, for example, one disclosed in Japanese Patent Application Laid-Open No. 7-318189 is disclosed. Can be used.

Reference numeral 5 denotes a heat exchanger of the indoor unit 4 installed in each room of the building. The heat exchanger 2 of the outdoor unit 1 is different from the heat exchanger 2 of the outdoor unit 1 as shown in FIG. The closed circuit 3 is formed by piping and connection by a valve 8.

The liquid-phase tube 6 is heated by the heat exchanger 5 of the indoor unit 4 to perform a heating action, and condensed.
A lower path including a receiver tank 9 for storing the tank 34a, an electric pump 10 for returning the R-134a stored in the tank to the outdoor unit 1, and a bypass including an on-off valve 11 in parallel with the lower path. An upper path is provided as a path so that the heat exchanger 2 of the outdoor unit 1 and the heat exchanger 5 of the indoor unit 4 can communicate with each other via one or both of the lower path and the upper path. I have.

Reference numeral 12 denotes a blower for blowing indoor air to the heat exchanger 5 to recirculate the indoor air, and reference numeral 13 denotes a regenerator of an absorption refrigerator (not shown) for heating the absorption liquid and evaporating and separating the refrigerant vapor. A fuel regulating valve provided on a fuel pipe connected to the burner 14, a pressure sensor 15 for detecting a pressure of R-134a condensed in the heat exchanger 2 and discharged to the liquid phase pipe 6, and 16 to 19 are closed. R-1 circulating in circuit 3
A temperature sensor for detecting the temperature of 34a is provided. The temperature sensors 16 and 17 are provided at the entrance and exit of the heat exchanger 2, and the temperature sensors 18 and 19 are provided at the exit of the heat exchanger 5.

The outdoor unit 1 and the indoor unit 4 are provided with an outdoor controller 20 and an indoor controller 21 which can communicate with each other. Then, the outdoor control device 20 controls the electric pump 10
During the cooling operation, the temperature of the R-134a detected by the temperature sensor 17, ie, the cooling by the heat exchanger 2, is condensed and condensed.
Is discharged to a predetermined temperature, for example, R-134a.
When the temperature of the R-134a detected by the temperature sensor 17 is equal to or lower than, for example, 7 ° C., the opening of the fuel adjustment valve 13 is adjusted. Is higher than 0 ° C. at which there is no concern that the R-134a will be in a supercooled state, the R-134a detected by the pressure sensor 15
a. Adjust the fuel so that the pressure of R-134a, that is, the pressure of R-134a condensed in the heat exchanger 2 and discharged to the liquid phase tube 6, becomes an equilibrium pressure of 7.5 Pa when R-134a condenses at 7 ° C. A function of adjusting the opening of the valve 13 is provided. During the heating operation, the temperature of the R-134a detected by the temperature sensor 16, that is, R which evaporates due to the heating action in the heat exchanger 2 and is discharged to the gas phase pipe 6. The indoor control device 21 has a function of adjusting the opening of the fuel adjustment valve 13 so that the temperature of −134a becomes a predetermined temperature, for example, 55 ° C.
9, the temperature of R-134a, ie, the heat exchanger 5
Is cooled and evaporates, and the temperature of the R-134a discharged to the gas phase pipe 7 after rising to a predetermined temperature, for example, 1
It has a function of adjusting the opening of the flow control valve 8 so as to reach 2 ° C., and the temperature sensor 18 detects R-13 during the heating operation.
R-13 which is condensed by performing a heating action via the heat exchanger 5, that is, the temperature is lowered and discharged to the liquid phase pipe 6.
A function is provided for adjusting the opening of the flow control valve 8 so that the temperature of 4a becomes a predetermined temperature, for example, 50 ° C.

A remote controller 22 communicable with the indoor controller 21 and capable of designating cooling and heating, starting and stopping operation, selecting the intensity of ventilation, setting the temperature, and the like is provided for each indoor unit 4.

In the outdoor unit 1, when the opening of the fuel regulating valve 13 is increased during operation in the cooling mode to increase the fuel supplied to the burner 14 to increase the thermal power, a regenerator (not shown) causes The amount of refrigerant that evaporates and separates from the water increases. This increased refrigerant vapor is radiated and condensed by a condenser (not shown), and the heat exchanger 2 provided in the evaporator.
R-1 which is supplied as a liquid around the heat exchanger and flows through the heat exchanger 2
Since the heat is removed from the heat exchanger 34a and evaporated, the function of cooling the R-134a flowing in the heat exchanger 2 is strengthened. Conversely, when the opening of the fuel regulating valve 13 is reduced to reduce the thermal power of the burner 14, the function of cooling the R-134a flowing in the heat exchanger 2 is weakened, and the temperature reduction width is reduced.

On the other hand, if the degree of opening of the fuel regulating valve 13 is increased during operation in the heating mode to increase the amount of fuel supplied to the burner 14 to increase the thermal power, the amount of refrigerant that evaporates and separates from the absorption liquid (not shown) increases. I do. With this increased refrigerant vapor,
The absorbing liquid that has been heated to evaporate and separate the refrigerant is supplied to the periphery of the heat exchanger 2 in the evaporator, and flows through the heat exchanger 2.
-134a, so that R- flows through the heat exchanger 2.
The function of heating 134a is strengthened, and if the flow rate is the same, the width of temperature rise increases. Conversely, when the opening of the fuel adjustment valve 13 is reduced to reduce the thermal power of the burner 14, the function of heating the R-134a flowing in the heat exchanger 2 is weakened,
The temperature rise is reduced.

On the other hand, in each indoor unit 4, if the opening of the flow control valve 8 is the same, as the air conditioning load increases, the temperature difference between the R-134a detected by the temperature sensors 18 and 19 increases, and the air conditioning load increases. Is smaller, the temperature difference is smaller.

Next, the circulation cycle of the R-134a sealed in the closed circuit 3 will be described.
The operation is performed in a state where the on-off valve 11 is opened and the operation of the electric pump 10 is stopped based on the control signal output from the control signal 0.
Then, in the outdoor unit 1, cold heat is generated as described above, and the cold heat causes the R-134a to be cooled and condensed through the tube wall of the heat exchanger 2, and the R-134a is cooled to a predetermined temperature of 7 ° C. and 7.5 Pa.
The liquid is discharged to the liquid phase pipe 6 and supplied to the indoor unit 4 via the on-off valve 11 and the flow control valve 8.

In each indoor unit 4, since the high temperature indoor air is forcibly supplied to the heat exchanger 5 by the blower 12, the R of the liquid supplied from the outdoor unit 1 at 7 ° C. and 7.5 Pa is supplied. -134a removes heat from indoor air and evaporates to perform a cooling operation.

The gas R-134a is R
-134a is cooled, condensed and liquefied, and the circulation naturally occurs such that it flows into the heat exchanger 2 of the outdoor unit 1 at a low pressure through the gas phase tube 7.

In the circulation of R-134a, when the cooling load in a certain indoor unit 4 increases (or decreases) and the temperature of R-134a detected by the temperature sensor 19 of the indoor unit 4 rises (or decreases), In order to eliminate the rise in temperature (or decrease in temperature), the opening degree of the corresponding flow control valve 8 increases (or decreases) in response to the control signal from the indoor control device 21, and the indoor unit having an increased cooling load Since the amount of R-134a flowing into the heat exchanger 5 of No. 4 increases (or decreases), R-13 detected by the temperature sensor 19 is
The temperature rise (or decrease) of 4a is eliminated.

A change in the pressure and temperature of the R-134a in the indoor unit 4 due to a change in the cooling load has an immediate effect on the pressure of the R-134a detected by the pressure sensor 15 in the outdoor unit 1. That is, if the temperature sensor 17 is R-134
The detection of the change in temperature a is effected only when the R-134a whose temperature has changed in the indoor unit 4 actually flows into the outdoor unit 1 (heat conduction is ignored compared to the circulation speed of R-134a). However, the change in pressure of R-134a in the indoor unit 4 is quickly transmitted to the outdoor unit 1 by propagation.

In the present invention, the outdoor control device 2
When the temperature sensor 17 detects a temperature higher than 0 ° C. at which there is no concern that the R-134a will be in a supercooled state, the R-134a has excellent responsiveness detected by the pressure sensor 15.
Responsiveness is poor when the opening of the fuel adjustment valve 13 is controlled based on the pressure of 134a and the temperature sensor 17 detects a temperature of 0 ° C. or less at which there is a concern that the R-134a may be in a supercooled state. The opening of the fuel adjustment valve 13 is controlled so that the temperature detected by the temperature sensor 17 becomes a predetermined 7 ° C. so that the temperature can be accurately controlled even when the R-134a is in a supercooled state.

Therefore, the opening degree of the fuel regulating valve 13, that is, the amount of cold generated for cooling the R-134a in the outdoor unit 1 is more responsive than the temperature when there is no concern that the R-134a falls into a supercooled state. It is controlled based on the excellent pressure, and when there is a concern that the R-134a will fall into a supercooled state, it is controlled based on a temperature that can be accurately controlled even when the R-134a becomes a supercooled state, and the R-134a falls into a supercooled state. Since this is prevented beforehand, it is possible to avoid a situation in which the refrigerant (water) of the absorption refrigerator constituting the outdoor unit 1 causes a supercooling phenomenon and freezes, leading to a shutdown.

The R-13 detected by the pressure sensor 15
The difference between the saturation temperature converted from the pressure of 4a and the temperature of R-134a detected by the temperature sensor 17 is a predetermined value, for example, 5
When the temperature is higher than 0 ° C., the R-134a may be in a supercooled state. Therefore, the opening degree of the fuel regulating valve 13 is controlled based on the temperature detected by the temperature sensor 17 so that the saturation temperature and the temperature sensor 17 detect the temperature. When the difference from the measured temperature of the R-134a is smaller than a predetermined value of 5 ° C., the supercooling state is not established, and the opening degree of the fuel adjustment valve 13 is controlled based on the pressure of the R-134a detected by the pressure sensor 15. You may do it.

By controlling the opening degree of the fuel adjusting valve 13 as described above, the required cold heat in the outdoor unit 1 can be generated promptly in response to a load change, and the outdoor unit 1 is constituted. It is possible to avoid the supercooling phenomenon of the refrigerant (water) of the absorption refrigerator.

The on-off valve 11 is closed and the electric pump 1
R-134 at the time of heating operation performed in a state where 0 is activated
Explaining the circulation cycle of a, the outdoor unit 1 generates heat as described above, and this heat causes R-1.
34a is heated through the tube wall of the heat exchanger 2, evaporates and discharges to the gas phase tube 7, and is supplied to each heat exchanger 5 of the indoor unit 4 at a predetermined temperature, for example, 55 ° C.

In each indoor unit 4, since the low temperature indoor air is forcibly supplied to the heat exchanger 5 by the blower 12, the R of the gas supplied from the outdoor unit 1 at 55 ° C.
-134a radiates heat to room air and condenses to perform a heating action.

Then, R-134 which has condensed and becomes liquid
a is stored in the receiver tank 9 and sent to the heat exchanger 2 of the outdoor unit 1 through the liquid phase tube 6 by the electric pump 10.

In the circulation of R-134a, when the heating load on a certain indoor unit 4 increases (or decreases) and the temperature of R-134a detected by the temperature sensor 18 of the indoor unit 4 decreases (or increases), In order to eliminate the temperature drop (or temperature rise), the opening degree of the corresponding flow control valve 8 increases (or decreases) in response to the control signal from the indoor control device 21, and the indoor unit in which the heating load increases has been increased. Since the amount of R-134a flowing into the heat exchanger 5 of No. 4 increases (or decreases), R-13 detected by the temperature sensor 19 is
The temperature drop (or rise) of 4a is resolved.

Then, the R-134a whose temperature has changed due to the fluctuation of the heating load flows into the outdoor unit 1, or the flow rate of the R-134a flowing into the outdoor unit 1 changes, and the temperature sensor 16 detects the change. When the temperature of the R-134a changes, the outdoor control device 20 controls the opening of the fuel adjustment valve 13 so as to eliminate the change. Further, R-134 detected by a pressure sensor installed in place of the temperature sensor 16 is used.
The opening degree of the fuel adjustment valve 13 may be controlled by the outdoor control device 20 so that the pressure a is constant.

The air conditioner may have a configuration in which a receiver tank 23 and an electric pump 24 as an auxiliary pump for cooling are installed in the liquid phase pipe 6, as shown by a broken line in FIG. In the air conditioner having such a configuration, in the cooling operation, the conveying force of the electric pump 24 acts in addition to the specific gravity difference between the liquid and the gas of R-134a. Can be installed on the same floor.

As shown by the broken line, the electric pump 1
The discharge side of 0 is closed during the cooling operation and connected to the inflow side of the receiver tank 23 via the on-off valve 25 that opens during the heating operation, and the electric pump 10 conveys to the outdoor unit 1 during the heating operation. The transport resistance of the liquid R-134a may be reduced, or an air conditioner dedicated to cooling operation by omitting the lower path including the receiver tank 9 and the electric pump 10 may of course be used.

Further, in addition to R-134a, R-407c and R-404, which can easily change phase by controlling temperature and pressure, as phase-changeable refrigerant sealed in the closed circuit 3 are used.
A, R-410c or the like.

[0035]

As described above, according to the control method of the present invention, it is possible to generate cold heat corresponding to a load change promptly and to prevent the outdoor unit from being supercooled.
Therefore, the outdoor unit that functions as a condenser can be configured by an absorption refrigerator that does not use electric power to generate cold heat, and it is possible to suppress electric power consumption in summer, when electric power consumption peaks.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of an air conditioner operated by a method of the present invention.

FIG. 2 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outdoor unit 2 Heat exchanger 3 Closed circuit 4 Indoor unit 5 Heat exchanger 6 Liquid phase pipe 7 Gas phase pipe 8 Flow control valve 9 Receiver tank 10 Electric pump 11 Opening / closing valve 12 Blower 13 Fuel control valve 14 Burner 15 Pressure sensor 16 -19 Temperature sensor 20 Outdoor control device 21 Indoor control device 22 Remote control 23 Receiver tank 24 Electric pump 25 On-off valve

Claims (2)

[Claims] 1. A refrigerant mainly capable of phase change between an outdoor unit functioning as a condenser and a plurality of indoor units functioning as an evaporator, all or a majority of which are installed below the outdoor unit. Circulating by utilizing the specific gravity difference between the phase and the gas phase, in an air conditioner configured to be able to cool in each indoor unit, the cold heat generation in an outdoor unit for cooling and condensing the refrigerant is condensed in the outdoor unit. Controlling the air conditioner based on the temperature of the refrigerant when the temperature of the refrigerant flowing is equal to or lower than a predetermined temperature, and controlling the temperature based on the pressure of the refrigerant when the temperature is higher than the predetermined temperature. 2. The method according to claim 1, wherein a refrigerant capable of phase change is mainly used as a liquid between an outdoor unit functioning as a condenser and a plurality of indoor units functioning as an evaporator, all or a majority of which are installed below the outdoor unit. Circulating utilizing the difference in specific gravity between the phase and the gas phase, in an air conditioner configured to be able to cool in each indoor unit, the generation of cold heat in an outdoor unit for cooling and condensing the refrigerant is condensed in the outdoor unit. When the difference between the saturated temperature converted from the pressure of the refrigerant flowing through and the temperature of the refrigerant measured by a thermometer is equal to or greater than a predetermined value, based on the temperature of the refrigerant, and when the difference is smaller than the predetermined value, A method for controlling an air conditioner, wherein the control is performed based on pressure.