JPH1163709A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drain dropping onto a drain pan from being frozen and ice from being accumulated by providing a sensor for detecting the temperature or the pressure of refrigerant in a supercooling heat exchanger and increasing the amount of restriction of a heating throttle mechanism when the detected value of the sensor is lowered to a value not higher than a prescribed value during a heating operation. SOLUTION: An electronic expansion valve 20 capable of adjusting the opening degree is connected in parallel with a check valve 15 in place of a capillary tube as a heating throttle mechanism. A sensor 26 for detecting temperature is attached to a supercooling heat exchanger 19 to increase or decrease the opening degree of the electronic expansion valve 20 in accordance with a command from the sensor 26. When outside temperature falls and the temperature or pressure of refrigerant in the supercooling heat exchanger 19 is lowered to a value not higher than a prescribed value during a heating operation, the valve opening degree of the electronic expansion valve 20 is decreased based on a command from the sensor 26 so that the amount of restriction thereof is increased. Then, the passage resistance of refrigerant passing through the electronic expansion valve 20 is increased so that the temperature and pressure of the refrigerant in the supercooling heat exchanger 19 are increased to maintain the temperature of the supercooling heat exchanger 19 to temperature not lower than 0 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an air conditioner.

[0002]

2. Description of the Related Art An example of a conventional air conditioner is shown in FIG. During the cooling operation of the air conditioner, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is, as shown by a solid line arrow,
In the process of flowing through a plurality of (three in the figure) circuits of the outdoor heat exchanger 18 through the four-way valve 2, heat is radiated to the outside air to be condensed and liquefied to become a high-pressure liquid refrigerant.

[0003] The liquid refrigerant passes through branch pipes 17a, 17b and 17c and joins in a distributor 16 and then passes through a check valve 15 to an outdoor heat exchanger.
In the process of flowing through the supercooling heat exchanger 19 integrated with the lower part of the part 18, the part is supercooled.

The liquid refrigerant is supplied to a joint 11, a connecting liquid pipe 10, a joint 9
Through the distributor 8 and is divided into a plurality (two in the figure) by a cooling device, and is adiabatically expanded by being throttled by cooling throttle mechanisms 7a and 7b each having a capillary tube interposed between the branch pipes 12a and 12b. Gas-liquid two-phase flow.

This refrigerant evaporates and evaporates into low-pressure refrigerant gas by cooling the room air in the process of flowing through a plurality of (two in the figure) circuits of the indoor heat exchanger 6, and becomes a low-pressure refrigerant gas. 4, joint 3, four-way valve 2, accumulator
It is sucked into the compressor 1 through 14.

During the heating operation of the air conditioner, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, the joint 3, the connecting gas pipe 4, and the joint 5, as indicated by the dashed arrows. In the process of flowing through the plurality of circuits of the exchanger 6, the room air is heated and condensed and liquefied to become a high-pressure liquid refrigerant.

The liquid refrigerant is partially decompressed in the course of passing through the cooling throttle mechanisms 7a and 7b interposed in the branch pipes 12a and 12b, and is joined by the distributor 8 before being joined by the joint 9 and the connecting liquid pipe. The heat is radiated to the outside air by the supercooling heat exchanger 19 via the joint 11 and the joint 11.

The liquid refrigerant is throttled in the process of flowing through the heating throttle mechanism 13 composed of a capillary tube, and adiabatically expands to form a gas-liquid two-phase flow. The liquid refrigerant branches at the distributor 16 and branches into the branch pipes 17a, 17b. , 17c, through the circuits of the outdoor heat exchanger 18, it absorbs heat from the outside air and evaporates to become low-pressure refrigerant gas, which is sucked into the compressor 1 through the four-way valve 2 and the accumulator 14.

During the heating operation, if the outside air temperature is low, frost adheres to the outdoor heat exchanger 18 and the heat absorption efficiency decreases, so that the defrost operation is performed by periodically switching the four-way valve 2 to perform the refrigerant. Is circulated as indicated by a solid line arrow in the same manner as in the cooling operation, so that the frost adhering to the outdoor heat exchanger 18 is melted and removed.

[0010]

In the above-described conventional air conditioner, when the outside air temperature decreases during the heating operation, the amount of heat absorbed by the outdoor heat exchanger 18 decreases, and the evaporation pressure decreases. As a result, the refrigerant circulation amount decreases. Then, since the flow resistance of the heating throttle mechanism 13 decreases, the pressure and temperature of the refrigerant in the supercooling heat exchanger 19 decrease.

Therefore, when the outside air temperature is extremely low, for example, -20
When the temperature drops to 0 ° C, the temperature of the supercooling heat exchanger 19 becomes 0 ° C.
The temperature of the outdoor heat exchanger 18 during defrost operation
Then, the drain water dripped onto the drain pan freezes, and the drain water drainage deteriorates, and ice accumulates on the drain pan, causing a problem that the supercooling heat exchanger 19 is deformed.

To cope with this, during the heating operation, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor is caused to flow into a freezing prevention heat exchanger disposed below the outdoor heat exchanger. Here, it has been proposed by Japanese Utility Model Laid-Open Publication No. 64-8176, Japanese Patent Application Laid-Open No. 6-1818064, etc. to suppress the freezing of drain water by releasing heat, but these are more effective for preventing freezing as the outside air temperature becomes lower. There has been a problem that the amount of heat released from the exchanger to the outside air increases and the heating capacity decreases.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the first invention is to provide a compressor, a four-way valve, an indoor heat exchanger, and cooling. Throttle mechanism, a heating throttle mechanism, an outdoor heat exchanger, and a subcooling heat exchanger integrated with the outdoor heat exchanger, and a liquid refrigerant condensed in the outdoor heat exchanger during cooling operation. Is supercooled by the supercooling heat exchanger, and the refrigerant radiated by the supercooling heat exchanger during the heating operation evaporates in the outdoor heat exchanger via the heating throttle mechanism. A sensor for detecting the temperature or pressure of the refrigerant in the cooling heat exchanger is provided, and when the detected value of the sensor decreases to a predetermined value or less during the heating operation, the throttle amount of the heating throttle mechanism is increased. Air conditioner.

Another feature is that the heating throttle mechanism is an electronic expansion valve whose valve opening can be adjusted, and the valve opening of the electronic expansion valve is reduced according to a decrease in the detection value of the sensor. It is in.

Still another feature is that the heating throttle mechanism is constituted by a plurality of fixed throttles connected in series, and an on-off valve is connected in parallel to a part of the fixed throttles. Is to close the above-mentioned on-off valve when the detection value falls below a predetermined value.

The gist of the second invention is that a compressor, a four-way valve, an indoor heat exchanger, a cooling throttling mechanism, a heating throttling mechanism, an outdoor heat exchanger, and a lower part of the outdoor heat exchanger. With an integrated supercooling heat exchanger, the liquid refrigerant condensed in the outdoor heat exchanger during cooling operation is supercooled by the supercooling heat exchanger, and the liquid refrigerant condensed by the supercooling heat exchanger during heating operation. In an air conditioner in which the radiated refrigerant evaporates in the outdoor heat exchanger via the heating throttle mechanism, the subcooling heat exchanger is divided into a plurality of parts and some of the divided subcooling heat exchangers are divided. Providing a sensor for detecting the temperature or pressure of the refrigerant of the present invention, and reducing the flow rate of the refrigerant flowing through the remaining subcooling heat exchanger divided when the detection value of the sensor drops below a predetermined value during the heating operation. An air conditioner characterized by the above.

Another feature is that a sensor for detecting the temperature or pressure of the refrigerant in the lowermost supercooling heat exchanger is provided, and when the detection value of the above sensor rises to a predetermined value or more during the heating operation. Another object of the present invention is to reduce the flow rate of refrigerant flowing through one or more supercooling heat exchangers above the lowermost supercooling heat exchanger.

Still another feature is that by reducing the opening degree of the electronic expansion valve whose valve opening degree can be adjusted and which is interposed in the outflow passage from the subcooling heat exchanger of the above-mentioned divided remaining part. The purpose is to reduce the flow rate of the refrigerant.

Still another feature is that the flow of the refrigerant is shut off by closing an on-off valve interposed in an outflow passage from the subcooling heat exchanger of the remaining portion.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. In the first embodiment, an electronic expansion valve 20 whose valve opening can be adjusted is connected in parallel with the check valve 15 instead of the capillary tube 13 as a heating throttle mechanism.
A sensor 26 for detecting the temperature is attached to the supercooling heat exchanger 19, and the degree of opening of the electronic expansion valve 20 is increased or decreased by a command from the sensor 26.

The sensor 26 may detect the temperature of the supercooling heat exchanger 19 and the inlet and outlet pipes thereof, or the temperature or pressure of the refrigerant therein. The other configuration is the same as that of the conventional one shown in FIG. 5, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

During the cooling operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 flows through a plurality of circuits of the outdoor heat exchanger 18 through the four-way valve 2 as indicated by solid arrows. In the process, heat is radiated to the outside air to condense and liquefy to become a high-pressure liquid refrigerant.

The liquid refrigerant passes through branch pipes 17a, 17b and 17c and joins in distributor 16 and then passes through check valve 15 to open-air heat exchanger.
In the process of flowing through the supercooling heat exchanger 19 integrated with the lower part of the part 18, the part is supercooled.

This liquid refrigerant is supplied to the joint 11, the connecting liquid pipe 10, the joint 9
And a cooling throttle mechanism composed of a capillary tube which is branched into a plurality of parts by the distributor 8 through the branch pipes 12a and 12b.
By being squeezed by 7a and 7b, adiabatic expansion and low-pressure gas-liquid two-phase flow are obtained.

This refrigerant evaporates and evaporates into low-pressure refrigerant gas by cooling indoor air in the process of flowing through a plurality of circuits of the indoor heat exchanger 6, and the joint 5, the connecting gas pipe 4, the joint 3, and the four-way It is sucked into the compressor 1 via the valve 2 and the accumulator 14.

During the heating operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, the joint 3, the connecting gas pipe 4, and the joint 5, as indicated by the dashed arrows, and the indoor heat exchanger 6. In the process of flowing through the plurality of circuits, the indoor air is heated and condensed and liquefied to become a high-pressure liquid refrigerant.

This liquid refrigerant is partially decompressed in the course of passing through the cooling throttle mechanisms 7a and 7b interposed in the branch pipes 12a and 12b, and is joined by the distributor 8 before being joined by the joint 9 and the connecting liquid pipe. The heat is radiated to the outside air by the supercooling heat exchanger 19 via the joint 11 and the joint 11.

This liquid refrigerant is adiabatically expanded by being throttled in the process of flowing through the electronic expansion valve 20 to form a gas-liquid two-phase flow, branched by the distributor 16 and passed through the branch pipes 17a, 17b, 17c to the outdoor room. In the course of flowing through each circuit of the heat exchanger 18, heat is absorbed from the outside air to evaporate and evaporate into low-pressure refrigerant gas, which is sucked into the compressor 1 via the four-way valve 2 and the accumulator 14.

During the heating operation, when the temperature or pressure of the refrigerant in the subcooling heat exchanger 19 falls below a predetermined value due to a decrease in the outside air temperature, the electronic expansion valve is operated by a command from the sensor 26 which detects this. The valve opening of the valve 20 becomes smaller, and the throttle amount increases. As a result, the flow resistance of the refrigerant flowing through the electronic expansion valve 20 increases, and the pressure and temperature of the refrigerant in the subcooling heat exchanger 19 increase, and the temperature of the subcooling heat exchanger 19 becomes zero.
Since the temperature is maintained at not less than ° C., it is possible to prevent the ice on the drain pan from growing and damaging the supercooling heat exchanger 19.

Further, since the valve opening of the electronic expansion valve 23 can be finely adjusted according to the detection value of the sensor 26, the pressure fluctuation of the supercooling heat exchanger 19 can be reduced and the supercooling heat exchanger 19 can be reduced. The temperature of No. 19 can be maintained at a predetermined temperature of 0 ° C. or more.

A second embodiment of the present invention is shown in FIG. In the second embodiment, an on-off valve 21 and a fixed throttle 22 formed of a capillary tube are provided between a refrigerant outlet of a supercooling heat exchanger 19 and a refrigerant inlet of a fixed throttle 13 formed of a capillary tube during a heating operation. The on-off valve 21 is opened and closed by a command from the sensor 26. The other configuration is the same as that of the conventional one shown in FIG. 5, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

When the temperature or pressure of the refrigerant in the supercooling heat exchanger 19 falls below a predetermined value due to a decrease in the outside air temperature during the heating operation, the on-off valve 14 is closed in response to a command from the sensor 26 which detects this. Becomes

Then, the liquid refrigerant flowing through the supercooling heat exchanger 19 flows through the capillary tubes 22 and 13 in this order, so that the throttle amount of the heating throttle mechanism increases and the flow path resistance increases. Since the refrigerant pressure in the supercooling heat exchanger 19 rises and the refrigerant temperature in the supercooling heat exchanger 19 rises accordingly, the temperature of the supercooling heat exchanger 19 rises to 0 ° C or more. Can be maintained.

When the pressure or temperature of the refrigerant in the subcooling heat exchanger 19 rises above a predetermined value, the on-off valve 14 is opened in response to a command from the sensor 26 that has detected this. Since the on-off valve 21 is kept open during the cooling operation, the liquid refrigerant condensed and liquefied in the outdoor heat exchanger 18 is branched into branch pipes 17a, 17b, 17c.
Then, it flows into the supercooling heat exchanger 19 via the distributor 16, the check valve 15, and the on-off valve 21, and is supercooled here.

A third embodiment of the present invention is shown in FIG. In the third embodiment, the first subcooling heat exchanger 19a is divided by dividing the subcooling heat exchanger.
And a second supercooling heat exchanger 19b. The first supercooling heat exchanger 19a is integrated with the outdoor heat exchanger 18 at a lower portion thereof, and the first supercooling heat exchanger 19a is formed. Is integrated with a second subcooling heat exchanger 19b.

During the cooling operation, the liquid refrigerant flowing through the check valve 15 branches into two, one of which passes through the electronic expansion valve 24 whose valve opening can be adjusted, and the first subcooling heat exchanger 19a. Flows into
The other flows into the second subcooling heat exchanger 19b.

During the heating operation, the liquid refrigerant partially depressurized by the cooling throttle mechanisms 7a, 7b is supplied to the subcooling coolers 19a, 19b.
Immediately before the second branch, one of them flows through the first supercooling heat exchanger 19a, and then flows through the second expansion subcooling heat exchanger 19b where the electronic expansion valve 24 flows. The liquid refrigerant flows and flows through the capillary tube 13 after being joined.

The valve opening of the electronic expansion valve 24 is adjusted by a command from a sensor 26 provided in the second subcooling heat exchanger 19b. The other configuration is the same as that of the conventional one shown in FIG. 5, and the corresponding members are denoted by the same reference numerals and description thereof will be omitted.

During the heating operation, when the temperature or pressure of the refrigerant in the second subcooling heat exchanger 19b drops below a predetermined value due to a decrease in the outside air temperature, the sensor 26 which detects this drops. With this command, the valve opening of the electronic expansion valve 24 decreases.

Thus, the first supercooling heat exchanger 19
As the amount of refrigerant flowing through the heat exchanger a decreases, the amount of heat radiation decreases, and the first and second supercooling heat exchangers 19a, 19b
Of the second subcooling heat exchanger 19
The temperature of b can be maintained at 0 ° C. or higher.

A fourth embodiment of the present invention is shown in FIG. The fourth embodiment is the same as the third embodiment shown in FIG. 3 except that an on-off valve 25 is used instead of the electronic expansion valve 24.

During the heating operation, when the temperature or pressure of the refrigerant in the second subcooling heat exchanger 19b falls below a predetermined value due to a decrease in the outside air temperature, the sensor 26 which has detected this decreases. , The on-off valve 25 is closed.

As a result, the liquid refrigerant does not flow through the first subcooling heat exchanger 19a but flows only through the second subcooling heat exchanger 19b and dissipates heat. The amount of heat radiation of the entire cooling heat exchangers 19a and 19b is reduced, and the pressure and temperature of the refrigerant in the second heat exchanger 19b can be increased. When the detection value of the sensor 26 becomes equal to or more than a predetermined value,
The opening / closing valve 25 is opened by a command from now on.

[0044]

According to the first aspect of the present invention,
A sensor for detecting the temperature or pressure of the refrigerant in the supercooling heat exchanger is provided. During the heating operation, when the detection value of this sensor drops below a predetermined value, the throttle amount of the heating throttle mechanism is increased to increase the supercooling. Since the pressure and temperature of the refrigerant in the heat exchanger for cooling rises and the temperature of the heat exchanger for supercooling can be maintained at 0 ° C. or higher, it is possible to prevent freezing of drain water on the drain pan.

Further, since the throttle amount of the heating throttle mechanism is increased only when the detection value of the sensor drops below a predetermined value, a decrease in the heating capacity can be suppressed.

If the heating throttle mechanism is an electronic expansion valve whose valve opening can be adjusted, and the valve opening of the electronic expansion valve is reduced in accordance with a decrease in the value detected by the sensor, the valve opening of the electronic expansion valve can be finely increased or decreased. Therefore, pressure fluctuation in the subcooling heat exchanger can be reduced.

When the heating throttle mechanism is constituted by a plurality of fixed throttles connected in series, and an on-off valve is connected in parallel to a part of the fixed throttle, and when the detection value of the sensor drops below a predetermined value, By closing the on-off valve, the throttle amount of the heating throttle mechanism can be increased.

According to the second aspect of the present invention, the sensor for dividing the subcooling heat exchanger into a plurality of parts and detecting the temperature or pressure of the refrigerant in some of the divided subcooling heat exchangers is provided. When the detected value of the heating operation sensor falls below a predetermined value, the amount of heat radiation of the entire subcooling heat exchanger is reduced by reducing the flow rate of the refrigerant flowing through the remaining subcooling heat exchanger divided. Therefore, the temperature of some subcooling heat exchangers can be maintained at 0 ° C. or higher.

A sensor for detecting the temperature or pressure of the refrigerant in the divided subcooling heat exchanger at the lowermost portion is provided, and when the detection value of the sensor during the heating operation drops below a predetermined value, the remaining portion of the divided If the flow rate of the refrigerant flowing through the subcooling heat exchanger is reduced, the temperature of the lowermost subcooling heat exchanger can be maintained at 0 ° C. or higher.

If the flow rate of the refrigerant is reduced by reducing the valve opening of the electronic expansion valve whose valve opening is adjustable, which is interposed in the outlet from the supercooling heat exchanger of the remaining divided portion, The temperature of the subcooling heat exchanger at the bottom can be finely adjusted.

If the refrigerant flow is shut off by closing an on-off valve interposed in the outflow path from the remaining subcooling heat exchanger, the temperature of the lowermost subcooling heat exchanger becomes zero. It can be maintained above ℃.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention.

FIG. 2 is a system diagram showing a second embodiment of the present invention.

FIG. 3 is a system diagram showing a third embodiment of the present invention.

FIG. 4 is a system diagram showing a fourth embodiment of the present invention.

FIG. 5 is a refrigerant circuit diagram of a conventional air conditioner.

[Explanation of symbols]

 Reference Signs List 1 compressor 2 four-way valve 6 indoor heat exchanger 7a, 7b cooling throttle mechanism 20 heating throttle mechanism 18 outdoor heat exchanger 19 supercooling heat exchanger 8 distributors 12a, 12b branch pipe 16 distributors 17a, 17b, 17c Branch pipe 14 Accumulator 15 Check valve 26 Sensor

Claims (7)

[Claims] 1. A compressor, a four-way valve, an indoor heat exchanger, a cooling throttle mechanism, a heating throttle mechanism, an outdoor heat exchanger, and a supercooling heat exchange integrated with a lower part of the outdoor heat exchanger. The liquid refrigerant condensed in the outdoor heat exchanger during the cooling operation is supercooled by the supercooling heat exchanger, and the refrigerant radiated by the supercooling heat exchanger during the heating operation is discharged by the heating throttle mechanism. In the air conditioner that evaporates in the outdoor heat exchanger through the above, a sensor for detecting the temperature or pressure of the refrigerant in the subcooling heat exchanger is provided, and the detection value of this sensor decreases to a predetermined value or less during the heating operation. An air conditioner characterized by increasing the amount of throttling of the throttling mechanism for heating. 2. The heating expansion mechanism according to claim 1, wherein the heating expansion mechanism is an electronic expansion valve whose valve opening can be adjusted, and the valve opening of the electronic expansion valve is reduced in accordance with a decrease in the value detected by the sensor. 2. The air conditioner according to 1. 3. The heating throttle mechanism is constituted by a plurality of fixed throttles connected in series, and an on-off valve is connected in parallel to a part of the fixed throttle, and a detection value of the sensor is equal to or less than a predetermined value. 2. The air conditioner according to claim 1, wherein the on-off valve is closed when the air conditioner drops. 4. A compressor, a four-way valve, an indoor heat exchanger, a cooling throttle mechanism, a heating throttle mechanism, an outdoor heat exchanger, and a heat exchange for supercooling integrated with a lower part of the outdoor heat exchanger. The liquid refrigerant condensed in the outdoor heat exchanger during the cooling operation is supercooled by the supercooling heat exchanger, and the refrigerant radiated by the supercooling heat exchanger during the heating operation is discharged by the heating throttle mechanism. In the air conditioner that evaporates in the outdoor heat exchanger through the above, the subcooling heat exchanger is divided into a plurality and the temperature or pressure of the refrigerant in some of the divided subcooling heat exchangers is detected. An air conditioner provided with a sensor, which reduces the flow rate of refrigerant flowing through the remaining subcooling heat exchanger divided when the detection value of the sensor drops below a predetermined value during a heating operation. 5. A sensor for detecting the temperature or pressure of the refrigerant in the divided lowermost supercooling heat exchanger, wherein when the detected value of the sensor decreases to a predetermined value or less during a heating operation,
The air conditioner according to claim 4, wherein the flow rate of the refrigerant flowing through the remaining subcooling heat exchanger that has been divided is reduced. 6. The refrigerant flow rate can be reduced by reducing the opening degree of an electronic expansion valve whose valve opening degree is adjustable, which is interposed in an outflow passage from the subcooling heat exchanger of the remaining part. The air conditioner according to claim 5, wherein 7. The air conditioner according to claim 5, wherein the refrigerant flow is shut off by closing an on-off valve interposed in an outflow passage from the subcooling heat exchanger of the remaining part. Machine.