JPH06272971A - Air conditioner - Google Patents

Abstract

PURPOSE:To expand the operation range in which a cooling operation can be performed continuously by opening a by-pass solenoid valve when a sensed temperature reaches a first set temperature during a cooling operation and stopping a compressor emergently when the sensed temperature reaches a second set temperature. CONSTITUTION:During a cooling operation, when an outlet pipe temperature T of an outdoor heat exchanger 3 exceeds a first set temperature (T1: 60 deg.), a by-pass solenoid valve 10 is opened, whereby the load of a compressor 1 is reduced. When, under conditions that the valve 10 is open, the outlet pipe temperature T of the exchanger 3 exceeds a second set temperature (T2: 67 deg.C), the compressor 1 is stopped emergently to protect it. And when, under conditions that the valve 10 is opened, the outlet pipe temperature T of the exchanger 3 falls below a third set temperature, the valve 10 is closed to restore its original condition. By opening the valve 10, the range of the operation is expanded and hence even if the suction temperature of the exchanger 3 rises, the cooling operation can be continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for controlling a bypass solenoid valve and for controlling a compressor in order to expand an operating range under severe installation conditions and temperature conditions. Is.

[0002]

2. Description of the Related Art Generally, an air conditioner is provided with a bypass path for capacity control in order to secure the proof strength against its installation environment and operating temperature conditions.

FIG. 9 shows, for example, Japanese Patent Laid-Open No. 63-19785.
It is a figure which shows the refrigerating cycle of the conventional air conditioner shown by the 3rd publication.

As shown in FIG. 9, the air conditioner has a compressor 1 for compressing a refrigerant such as Freon, and the discharge side of the compressor 1 is a refrigerant suitable for a high pressure and high temperature gas refrigerant. Piping 7
a is connected. At the other end of the refrigerant pipe 7a, a four-way valve 2 that switches its direction between cooling and heating
Are connected, the solid line indicates cooling, and the broken line indicates heating. Further, the four-way valve 2 is connected to an outdoor heat exchanger 3 for exchanging heat between the refrigerant and the outside air via a refrigerant pipe 7b, and the outdoor heat exchanger 3 is a pipe for passing a blower fan and the refrigerant. It functions as a condenser during cooling and as an evaporator during heating.

The outdoor heat exchanger 3 has a capillary tube 4a as a throttle means for squeezing and expanding the high-pressure refrigerant liquefied by the outdoor heat exchanger 3, and a check valve 21a for blocking the inflow of the refrigerant during cooling. Are connected in parallel, and the capillary tube 4a and the check valve 21a are connected to each other.
A check valve 21b, which is opened during cooling through the refrigerant pipe 8a and blocks the inflow of refrigerant during heating, and a throttle means for squeezing and expanding high-pressure refrigerant liquefied by an indoor heat exchanger 5 described later during heating. Capillary tube 4
b and b are connected in parallel. An indoor heat exchanger 5 for exchanging heat between the refrigerant and the outside air is connected to the capillary tube 4b and the check valve 21b, and the indoor heat exchanger 5 includes a blower fan and a pipe through which the refrigerant passes. It functions as a condenser during heating and as an evaporator during cooling.

Further, the indoor heat exchanger 5 has a refrigerant pipe 8b.
The four-way valve 2 is connected through the accumulator 6 for storing the gas refrigerant evaporated by the indoor heat exchanger 5 or the outdoor heat exchanger 3 via the refrigerant pipe 8c.
Is connected, and the suction side of the compressor 1 is connected to the accumulator 6 via the refrigerant pipe 8d.

A bypass line 9 is connected between the refrigerant pipe 7a on the discharge side of the compressor 1 and the refrigerant pipe 8a connecting the capillary tube 4a and the check valve 21b. A bypass solenoid valve 10 is provided in the.

Next, the operation will be described.

During cooling, the compressor 1 draws in a low-pressure low-temperature gas refrigerant from the accumulator 6, compresses it, and uses it as a high-pressure high-temperature gas refrigerant as a refrigerant pipe 7a, a four-way valve 2 and a refrigerant pipe 7b.
And is delivered to the outdoor heat exchanger 3. Then, the outdoor heat exchanger 3 transfers the high-pressure and high-temperature gas refrigerant to the outside air (for example, 35 ° C.).
Is cooled and liquefied to obtain a high-pressure liquid refrigerant.

Then, the liquid refrigerant expands and is depressurized when passing through the capillary tube 4a to become a low-pressure liquid refrigerant, and the low-pressure liquid refrigerant passes through the refrigerant pipe 8a and the check valve 21b to heat the indoor heat. It is evaporated in the exchanger 5 to become a gas refrigerant. Since the capillary tube 4b has a large resistance, the liquid refrigerant passes only the check valve 21b. At this time, the indoor air is cooled by the temperature drop due to the evaporation of the refrigerant, and the room is cooled. Further, the gas refrigerant is the refrigerant pipe 8
b, return to the accumulator 6 through the four-way valve 2 and the refrigerant pipe 8c.

On the other hand, during heating, the four-way valve 2 is switched as shown by the broken line. The high-pressure and high-temperature gas refrigerant compressed by the compressor 1 is sent to the indoor heat exchanger 5 through the refrigerant pipe 8b, and the indoor heat exchanger 5 liquefies the high-pressure and high-temperature gas refrigerant by cooling it with indoor air. The high-pressure liquid refrigerant. That is, the room air is warmed by the heat of the high-temperature gas refrigerant, and the room is heated.

Then, this liquid refrigerant expands and is depressurized when passing through the capillary tube 4b to become a low-pressure liquid refrigerant, and this low-pressure liquid refrigerant passes through the refrigerant pipe 8a and the check valve 21a to generate outdoor heat. It is evaporated in the exchanger 3 to become a gas refrigerant. Further, the gas refrigerant is the refrigerant pipe 7b, the four-way valve 2
And it returns to the accumulator 6 through the refrigerant pipe 8c.

Further, since the outside air may be 0 ° C. or less during heating, frost may be formed on the capillary tube 4b and the outdoor heat exchanger 3. Therefore, the bypass solenoid valve 10 is opened every predetermined time, the high temperature gas refrigerant compressed by the compressor 1 is supplied to the capillary tube 4b and the outdoor heat exchanger 3, and so-called hot gas defrost that melts the adhered frost is generated. To do.

Further, when the indoor air temperature rises during heating or the discharge pressure of the compressor 1 increases due to a decrease in the air volume of the blower fan due to the clogging of the filter of the outdoor heat exchanger 3, the bypass The solenoid valve 10 is opened to prevent the discharge pressure of the compressor 1 from rising abnormally.

[0015]

The conventional air conditioner is
It is configured as described above, and proposes expansion of the operating range under the temperature conditions of the low temperature condition side during cooling and heating, that is, the low temperature condition side during cooling, and the high temperature condition side during heating. . A similar proposal is disclosed in, for example, Japanese Patent Laid-Open No. 1-1
There is an air conditioner using a capacity control type compressor disclosed in Japanese Patent No. 47265.

However, looking at the installation environment of recent air conditioners, the problem is that the air conditioning load is larger than the problem when the air conditioning load is low, especially when the temperature is high during cooling operation. It has become. That is, by installing an outdoor heat exchanger in a narrow space due to lack of installation space for the outdoor heat exchanger and deterioration of the installation environment, a short cycle may occur and air stagnation may occur due to poor ventilation of the outdoor heat exchanger. As a result, it is forced to operate at a suction air temperature that is considerably higher than the outside air temperature, resulting in an abnormal increase in refrigerant pressure and a rise in compressor discharge temperature during cooling operation, which exceeds the allowable operating range of the compressor. Therefore, it often happens that the air conditioner is abnormally stopped and the original cooling effect cannot be obtained.

Further, cooling is most necessary under the condition that the outside air temperature is high. However, in the above-mentioned conventional air conditioner, when the outside air temperature exceeds the predetermined condition, the air conditioner is temporarily stopped. There is a problem in that the original cooling operation cannot be performed because the compressor is protected by either performing it or stopping it abnormally.

Further, when the compressor is once stopped under such conditions, a control method for facilitating the starting of the compressor after the stop is presented in, for example, Japanese Patent Laid-Open No. 233255/1988. However, the control method of this publication does not continue the cooling operation when cooling is required.

The present invention has been made to solve the above-mentioned problems, and the installation environment of the outdoor heat exchanger is bad under the overload condition of the cooling operation of the air conditioner, that is, the condition that the outside air temperature is high. Causing some short cycles,
Even when the ventilation around the outdoor heat exchanger is bad and air stagnation occurs, the air conditioner does not stop abnormally and avoids the severe operation that causes the failure of the compressor, thus continuously performing the cooling operation. The purpose is to obtain an air conditioner with an expanded operating range.

[0020]

An air conditioner according to the present invention is a compressor for compressing a refrigerant, an outdoor heat exchanger for exchanging heat between the refrigerant and the outside air, and a refrigerant and a room. An indoor heat exchanger for exchanging heat with air, a throttle means for expanding the high-pressure refrigerant liquefied by the outdoor heat exchanger or the indoor heat exchanger, a compressor, an outdoor heat exchanger, a throttle means, And a refrigerant pipe that sequentially connects the indoor heat exchangers, a first bypass path that is connected from the discharge-side high-pressure pipe of the compressor to the refrigerant pipe that connects the expansion mechanism and the indoor heat exchanger, and is arranged in the bypass path. The bypass solenoid valve, the temperature detecting means provided in the outlet pipe of the outdoor heat exchanger, the first preset temperature and the second preset temperature higher than the first preset temperature, and the cooling is performed. During operation, the temperature detected by the temperature detecting means is the first set temperature. A control device for opening the bypass solenoid valve when the temperature reaches a predetermined temperature, and for making an emergency stop of the compressor when the temperature detected by the temperature detecting means reaches a second set temperature. .

An air conditioner according to a second aspect of the invention is
A compressor that compresses the refrigerant, an outdoor heat exchanger that performs heat exchange between the refrigerant and the outside air, an indoor heat exchanger that performs heat exchange between the refrigerant and the indoor air, and an outdoor heat exchanger or indoor heat From the expansion means that restricts and expands the high-pressure refrigerant liquefied by the exchanger, the refrigerant piping that sequentially connects the compressor, the outdoor heat exchanger, the expansion means, and the indoor heat exchanger, and the high-pressure piping on the discharge side of the compressor. A second bypass path connected to the suction-side low-pressure refrigerant pipe, a bypass solenoid valve arranged in the bypass path, a temperature detecting means provided in the outlet pipe of the outdoor heat exchanger, and a first set temperature. A second preset temperature higher than the first preset temperature is preset, and the bypass solenoid valve is opened when the detected temperature of the temperature detecting means reaches the first preset temperature during the cooling operation, The temperature detected by the temperature detecting means becomes the second set temperature. It is characterized in that when a control device for emergency stop of the compressor.

An air conditioner according to a third aspect of the invention is
A compressor that compresses the refrigerant, an outdoor heat exchanger that performs heat exchange between the refrigerant and the outside air, an indoor heat exchanger that performs heat exchange between the refrigerant and the indoor air, and an outdoor heat exchanger or indoor heat From the expansion means that restricts and expands the high-pressure refrigerant liquefied by the exchanger, the refrigerant piping that sequentially connects the compressor, the outdoor heat exchanger, the expansion means, and the indoor heat exchanger, and the high-pressure piping on the discharge side of the compressor. A second bypass path connected to the suction-side low-pressure refrigerant pipe; a bypass solenoid valve arranged in the bypass path; and a temperature detecting means for detecting the discharge refrigerant temperature of the compressor,
When the first set temperature and the second set temperature higher than the first set temperature are set in advance and the detected temperature of the temperature detecting means reaches the first set temperature during the cooling operation, the bypass electromagnetic And a control device for opening the valve and stopping the compressor in an emergency when the temperature detected by the temperature detecting means reaches the second set temperature.

[0023]

In the air conditioner according to the present invention, the first preset temperature and the second preset temperature higher than the first preset temperature are set in the control device in advance, and the outlet pipe of the outdoor heat exchanger is set in the cooling operation. When the temperature detected by the temperature detecting means provided reaches the first set temperature, the bypass solenoid valve is opened, and when the temperature detected by the temperature detecting means reaches the second set temperature, the compressor is turned off. By stopping, the operating range can be expanded and the cooling operation can be continued under the cooling overload condition without increasing the load on the compressor.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

(1) First Embodiment FIG. 1 is a configuration diagram showing a refrigeration cycle of an air conditioner according to the invention described in claim 1.

As shown in FIG. 1, the air conditioner has a compressor 1 for compressing a refrigerant such as Freon, and the discharge side of the compressor 1 is a refrigerant suitable for a high pressure and high temperature gas refrigerant. Piping 7
a is connected. At the other end of the refrigerant pipe 7a, a four-way valve 2 that switches its direction between cooling and heating
Are connected, the solid line indicates cooling, and the broken line indicates heating. Further, the four-way valve 2 is connected to an outdoor heat exchanger 3 for exchanging heat between the refrigerant and the outside air via a refrigerant pipe 7b, and the outdoor heat exchanger 3 is a pipe for passing a blower fan and the refrigerant. It is an outdoor fan coil unit consisting of, and functions as a condenser during cooling and as an evaporator during heating.

A capillary tube 4 is connected to the outdoor heat exchanger 3 as a throttle means for squeezing and expanding the high-pressure refrigerant liquefied by the outdoor heat exchanger 3 during cooling.
An indoor heat exchanger 5 for exchanging heat between the refrigerant and the outside air is connected to the capillary tube 4 via a refrigerant pipe 8a. The indoor heat exchanger 5 includes a blower fan and a pipe through which the refrigerant passes. This indoor fan coil unit functions as a condenser during heating and as an evaporator during cooling. Furthermore, in the indoor heat exchanger 5,
The four-way valve 2 is connected via a refrigerant pipe 8b, and the four-way valve 2 is connected to an accumulator 6 for storing the gas refrigerant evaporated by the indoor heat exchanger 5 or the outdoor heat exchanger 3 via a refrigerant pipe 8c. The suction side of the compressor 1 is connected to the accumulator 6 via a refrigerant pipe 8d.

A bypass line 9 is connected between the refrigerant pipe 7a on the discharge side of the compressor 1 and the refrigerant pipe 8a connecting the capillary tube 4 and the indoor heat exchanger 5, and the bypass line 9 is connected. A bypass solenoid valve 10 is arranged therein. Further, the bypass solenoid valve 10 and the compressor 1 are electrically connected with a control device 12 for controlling the operation thereof, and the control device 12 is provided with a temperature detection device provided in an outlet pipe of the outdoor heat exchanger 3. Means 11 are connected. The temperature detecting means 11 is composed of a thermistor, a thermocouple, a bimetal thermostat, a refrigerant gas pressure type thermostat, and the like, and is not limited to that type.

Next, the operation of this embodiment will be described.

During cooling, the compressor 1 draws in the low-pressure low-temperature gas refrigerant from the accumulator 6, compresses it, and uses it as the high-pressure high-temperature gas refrigerant in the refrigerant pipe 7a, the four-way valve 2 and the refrigerant pipe 7b.
And is delivered to the outdoor heat exchanger 3. Then, the outdoor heat exchanger 3 transfers the high-pressure and high-temperature gas refrigerant to the outside air (for example, 35 ° C.).
Is cooled and liquefied to obtain a high-pressure liquid refrigerant.

Then, this liquid refrigerant is expanded and depressurized when passing through the capillary tube 4 to become a low pressure liquid refrigerant, and this low pressure liquid refrigerant is evaporated in the indoor heat exchanger 5 through the refrigerant pipe 8a. And becomes a gas refrigerant. At this time, the indoor air is cooled by the temperature drop due to the evaporation of the refrigerant, and the room is cooled. Further, the gas refrigerant is the refrigerant pipe 8
b, return to the accumulator 6 through the four-way valve 2 and the refrigerant pipe 8c.

On the other hand, during heating, the four-way valve 2 is switched as shown by the broken line. The high-pressure and high-temperature gas refrigerant compressed by the compressor 1 is sent to the indoor heat exchanger 5 through the refrigerant pipe 8b, and the indoor heat exchanger 5 liquefies the high-pressure and high-temperature gas refrigerant by cooling it with indoor air. The high-pressure liquid refrigerant. That is, the room air is warmed by the heat of the high-temperature gas refrigerant, and the room is heated.

Then, this liquid refrigerant is sent to the capillary tube 4 through the refrigerant pipe 8a, and when passing through the capillary tube 4, it is expanded and decompressed to become a low pressure liquid refrigerant. It evaporates in the outdoor heat exchanger 3 to become a gas refrigerant. Further, the gas refrigerant returns to the accumulator 6 through the refrigerant pipe 7b, the four-way valve 2 and the refrigerant pipe 8c.

Further, in the outdoor heat exchanger 3, heat is exchanged between the high temperature gas refrigerant compressed by the compressor 1 and the outside air, and the gas refrigerant releases heat to the outside air and condenses into a liquid refrigerant. However, when ventilation around the outdoor heat exchanger 3 is poor and air stagnation occurs, the temperature of the air passing through the outdoor heat exchanger 3 rises, heat exchange deteriorates, and as a result, the discharge pressure of the compressor 1 rises. Moreover, the temperature of the refrigerant discharged from the compressor 1 also rises abnormally. Further, if the compressor 1 is not operated below a predetermined discharge pressure and discharge refrigerant temperature, the bearing or the like will be damaged. Therefore, it is necessary to always operate below this restriction pressure and temperature. The solenoid valve 10 is opened, and the control device 12 controls the discharge pressure and the discharge refrigerant temperature to be low.

That is, when the bypass solenoid valve 10 of the bypass path 9 is opened during cooling, part of the refrigerant discharged from the compressor 1 passes through the bypass path 9 and the inlet side of the indoor heat exchanger 5 as an evaporator. Is supplied to the indoor heat exchanger 5, the evaporation capacity of the indoor heat exchanger 5 is reduced, and the amount of circulating refrigerant to the outdoor heat exchanger 3 as a condenser is reduced, so that the condensation pressure, that is, the discharge pressure can be suppressed to a low level. As a result, the discharged refrigerant temperature can be lowered.

FIG. 2 shows the limit operating characteristics of the air conditioner of the present invention under cooling overload conditions. As an operating condition, the indoor temperature is constant at 35 ° C. in any case.
Driving NO. The air conditioners A and B have an outdoor temperature, that is, an intake air temperature of the outdoor heat exchanger 3 of 53.5 ° C.
Driving NO. In the air conditioner A, the bypass solenoid valve 10 is closed and the operation NO. B air conditioner has bypass solenoid valve 1
The operating state with 0 open is shown. In addition, driving N
O. The air conditioner of C operates with the operation No. The operating state when the outdoor temperature is raised from the same state as the air conditioner of B is shown. Driving NO. In the air conditioner A, the discharge pressure of the compressor 1 is 3.10 MPa (about 30.7 kgf / cm ² G).
(G indicates a gauge pressure), and the discharge temperature is 119.8 ° C., but in this state the limit of the allowable operating range of the compressor 1 has already been reached, so the bypass solenoid valve 10 is opened and the operating NO. By making it in the same state as the air conditioner of B,
The discharge pressure and the discharge refrigerant temperature of the compressor 1 are set to 2.8.
6 MPa (about 28.2 kgf / cm ² G), 103.0
It can be reduced to ° C.

Although the limit values of the allowable operating range of the discharge pressure and the discharge temperature of the compressor 1 cannot be generally stated, the discharge pressure should be kept to 3.04 MPa (about 30 kgf / cm ² G) and the discharge temperature to 120 ° C. or less. is necessary. Then, in this embodiment, the temperature detection means 11 attached to the outlet side pipe of the outdoor heat exchanger 3 detects the limit of the allowable operating range of the compressor 1, and the discharge pressure and discharge temperature of the compressor 1 and the outdoor heat. Since the outlet pipe temperature of the exchanger 3 has a predetermined relationship, it is possible to estimate whether or not the discharge pressure and the discharge temperature are at the limit values based on this temperature.

FIG. 3 and FIG. 4 are characteristic diagrams showing a predetermined relationship between the outdoor heat exchanger outlet temperature and the compressor outlet pipe temperature when the outdoor air temperature is changed during the cooling operation. As shown in FIGS. 3 and 4, it can be seen that when the discharge pressure and discharge temperature of the compressor 1 rise as the outside air temperature rises, the outdoor unit heat exchanger 3 outlet pipe temperature also rises in a predetermined relationship. Here, the characteristics are not continuous in the closed state and the opened state of the bypass solenoid valve 10, but this is for the following reason.

That is, when the bypass solenoid valve 10 is opened and part of the refrigerant discharged from the compressor 1 is bypassed to the inlet side of the indoor heat exchanger 5, the amount of refrigerant circulated to the outdoor heat exchanger 3 decreases. However, since the capillary tube as the throttling means is the same, the throttling amount consequently becomes less and the degree of supercooling is reduced, and the outlet pipe temperature of the outdoor heat exchanger is proportional to the discharge pressure and the discharge temperature decrease. The result is not much reduced. The operation No. of FIG. Comparing the operating states of A and B, the discharge pressure is reduced from 3.10 MPa (about 30.7 kgf / cm ² G) to 2.86 MPa (about 28.2 kgf / cm ² G) by opening the bypass solenoid valve 10. However, the temperature of the outdoor heat exchanger outlet piping is 62.4 ° C.
To 62.8 ° C, which is almost unchanged.

Therefore, in order to control the temperature at the outlet pipe of the outdoor heat exchanger, the bypass solenoid valve 10 is used as the control temperature.
It is necessary to divide the control temperature according to the open / close state of. According to the characteristics of FIGS. 3 and 4, the discharge pressure is 3.04 MPa (about 30 kgf / cm ² G) when the bypass solenoid valve 10 is closed.
Hereinafter, in order to suppress the discharge temperature to 120 ° C. or lower, it is necessary to set the temperature of the outdoor heat exchanger outlet pipe to about 60 ° C. or lower, and when the bypass solenoid valve 10 is open, the discharge pressure is 3.04 MPa (about In order to keep the discharge temperature at 30 kgf / cm ² G) or lower and the discharge temperature at 120 ° C. or lower, it is necessary to set the outdoor heat exchanger outlet piping temperature to about 67 ° C. or lower.

Therefore, in the air conditioner of this embodiment, the first set temperature is preset to 60 ° C. and the second set temperature is set to 67 ° C., and the outdoor heat exchanger outlet detected by the temperature detecting means 11 is detected. The bypass solenoid valve 10 and the compressor 1 are connected to the controller 1 by comparing the pipe temperature with the first and second set temperatures.
It is controlled by 2.

FIG. 5 is a flow chart showing the control operation of the bypass solenoid valve during the cooling operation by the controller of the air conditioner according to this embodiment. The operation of the control device will be described below with reference to this flowchart.

The controller 12 determines whether the air conditioner is in an operating state (step 1), and if it is in an operating state, determines whether it is in an abnormal mode (step 2). When it is determined that the abnormal mode is not set, the control device 12
Starts the compressor 1 (step 3), and the outdoor heat exchanger 3
The outlet pipe temperature T of the outdoor heat exchanger 3 is detected by the temperature detecting means 11 provided on the outlet side of the (step 4). Then, the control device 12 determines the current open / closed state of the bypass solenoid valve 10 of the bypass path 9 (step 5), and when the bypass solenoid valve 10 is closed, the outlet pipe temperature T of the outdoor heat exchanger 3 and the outlet pipe temperature T are determined in advance. A comparison is made with the set first set temperature (T1: 60 ° C.) (step 6), and if the pipe temperature T is higher than the first set temperature T1, the bypass solenoid valve 10 is opened (step 7), Return to step 1.

If it is determined in step 5 that the bypass solenoid valve 10 is open, the controller 12
Compares the outlet pipe temperature T of the outdoor heat exchanger 3 with a preset second set temperature (T2: 67 ° C.) (step 8), and the pipe temperature T is higher than the second set temperature T2. If it is also high, the abnormal mode is set (step 9), and the compressor 1
Is stopped (step 10), the bypass solenoid valve 10 is closed (step 11), and the process returns to step 1. When it is determined that the pipe temperature T is lower than the second set temperature T2, the control device 12 determines whether the pipe temperature T is lower than a preset third set temperature T3, and the pipe temperature T T
Is lower than the third set temperature T3, the above step 11
Performs the following operations. Further, when the pipe temperature T is higher than the third set temperature T3, nothing is performed and the process returns to step 1.

On the other hand, when it is determined in step 1 that the air conditioner is not in the operating state, the control device 12
The operation after step 10 is performed. Furthermore, the above-mentioned step 2
When it is determined that the abnormal mode is set in, the operation after step 9 is performed.

As described above, the outlet pipe temperature T of the outdoor heat exchanger 3 during the cooling operation is the first set temperature (T1: 60 ° C.).
When the temperature exceeds the limit, the load of the compressor 1 is reduced by opening the bypass solenoid valve 10, and the outlet pipe temperature T of the outdoor heat exchanger 3 is set to the second set temperature (T2: 67 when the bypass solenoid valve 10 is opened). (° C), the compressor 1 is stopped to protect it. Further, when the outlet pipe temperature T of the outdoor heat exchanger 3 falls below the third set temperature with the bypass solenoid valve 10 open, the bypass solenoid valve 10 is closed and returned to the original state. This is because when the bypass solenoid valve 10 is opened, the load on the compressor 1 can be reduced, but the cooling capacity is slightly reduced and the operating efficiency is deteriorated. Therefore, the operating conditions are eased and the outdoor heat exchanger 3 is cooled. If the outlet pipe temperature T falls below a predetermined temperature and the bypass solenoid valve 10 is closed but the limit value of the allowable operating range of the compressor 1 is not exceeded, the bypass solenoid valve 10 is closed for efficient operation. It is for doing. The third set temperature is lower than the first set temperature by a predetermined temperature.

When the degree of expansion of the operating range during the cooling operation by the above control is estimated from the actual machine operation data shown in FIG. 2, the operation NO. Operation No. A with bypass solenoid valve 10 and bypass solenoid valve 10 open. Compressor 1 with C
Since the discharge pressures of the two are almost the same, the difference in outdoor temperature at this time (59.3 ° C-53.5 ° C = 5.8 deg)
However, it can be considered that the operating range is expanded by opening the bypass solenoid valve 10, and it is about 5 to 6 as compared with the conventional device.
Even if the suction temperature of the outdoor heat exchanger 3 rises by ° C, the cooling operation can be continued.

(2) Second Embodiment Next, an embodiment according to the present invention will be described with reference to the drawings. FIG. 6 is a configuration diagram showing a refrigeration cycle of the air conditioner of the second embodiment. The same components as those in FIG. 1 described above are designated by the same reference numerals and the description thereof will be omitted.

A bypass passage 9 is connected between the refrigerant pipe 7a and the refrigerant pipe 8c on the discharge side of the compressor 1, and a bypass solenoid valve 10 is arranged in the bypass passage 9. The bypass solenoid valve 10, the compressor 1, and the temperature detecting means 11 are connected to the control device 12.

Next, the operation of this embodiment will be described.

During cooling, the compressor 1 draws in the low-pressure low-temperature gas refrigerant from the accumulator 6, compresses it, and uses it as the high-pressure high-temperature gas refrigerant as the refrigerant pipe 7a, the four-way valve 2 and the refrigerant pipe 7b.
And is delivered to the outdoor heat exchanger 3. Then, the outdoor heat exchanger 3 transfers the high-pressure and high-temperature gas refrigerant to the outside air (for example, 35 ° C.).
Is cooled and liquefied to obtain a high-pressure liquid refrigerant.

Then, this liquid refrigerant is expanded and depressurized when passing through the capillary tube 4 to become a low pressure liquid refrigerant, and this low pressure liquid refrigerant is evaporated in the indoor heat exchanger 5 through the refrigerant pipe 8a. And becomes a gas refrigerant. At this time, the indoor air is cooled by the temperature drop due to the evaporation of the refrigerant, and the room is cooled. Further, the gas refrigerant is the refrigerant pipe 8
b, return to the accumulator 6 through the four-way valve 2 and the refrigerant pipe 8c.

On the other hand, during heating, the four-way valve 2 is switched as shown by the broken line. The high-pressure and high-temperature gas refrigerant compressed by the compressor 1 is sent to the indoor heat exchanger 5 through the refrigerant pipe 8b, and the indoor heat exchanger 5 liquefies the high-pressure and high-temperature gas refrigerant by cooling it with indoor air. The high-pressure liquid refrigerant. That is, the room air is warmed by the heat of the high-temperature gas refrigerant, and the room is heated.

Then, this liquid refrigerant is sent to the capillary tube 4 through the refrigerant pipe 8a, and when passing through the capillary tube 4, it is expanded and decompressed to become a low-pressure liquid refrigerant. This low-pressure liquid refrigerant is It evaporates in the outdoor heat exchanger 3 to become a gas refrigerant. Further, the gas refrigerant returns to the accumulator 6 through the refrigerant pipe 7b, the four-way valve 2 and the refrigerant pipe 8c.

Further, the temperature of the outside air rises, the environment in which the outdoor heat exchanger 3 is installed is bad, and a short cycle occurs.
Ventilation around the outdoor heat exchanger 3 is poor and air stagnation occurs,
When the temperature of the air passing through the outdoor heat exchanger 3 rises and the heat exchange deteriorates, and as a result, the discharge pressure of the compressor 1 rises and the discharge refrigerant temperature of the compressor 1 also rises abnormally, the bypass path 9 The bypass solenoid valve 10 is opened and the control device 12 controls the discharge pressure and the discharge refrigerant temperature of the refrigerant discharged from the compressor 1 to be low.

That is, when the bypass solenoid valve 10 of the bypass path 9 is opened during cooling, a part of the refrigerant discharged from the compressor 1 is supplied to the suction side of the compressor 1 through the bypass path 9. The amount of the refrigerant circulated to the main refrigeration cycle is reduced, the condensing pressure, that is, the discharge pressure can be suppressed low, and as a result, the discharged refrigerant temperature can be lowered. Here, as a matter of course, the opening / closing timing of the bypass solenoid valve 10 needs to be performed so as not to exceed the allowable operating range of the compressor 1. Even in the air conditioner of the second embodiment, the outdoor heat exchanger outlet side piping is The temperature is detected by the attached temperature detecting means 11. Since the discharge pressure and discharge temperature of the compressor 1 and the outlet pipe temperature of the outdoor heat exchanger 3 have a predetermined relationship, it is possible to estimate whether or not the discharge pressure and discharge temperature are at their limit values by this temperature. It is possible.

FIG. 7 and FIG. 8 are characteristic diagrams showing a predetermined relationship between the outdoor heat exchanger outlet temperature and the compressor outlet pipe temperature when the outdoor air temperature is changed during the cooling operation. As shown in FIGS. 7 and 8, it can be seen that when the discharge pressure and discharge temperature of the compressor 1 rise as the outside air temperature rises, the outdoor unit heat exchanger 3 outlet pipe temperature also rises in a predetermined relationship. Here, the characteristics are not continuous in the closed state and the opened state of the bypass solenoid valve 10, but this is for the same reason as in the above-described first embodiment.

That is, when the bypass solenoid valve 10 is opened and part of the refrigerant discharged from the compressor 1 is bypassed to the inlet side of the indoor heat exchanger 5, the amount of refrigerant circulated to the outdoor heat exchanger 3 is reduced. However, since the capillary tube as the throttling means is the same, the throttling amount consequently becomes less and the degree of supercooling is reduced, and the outlet pipe temperature of the outdoor heat exchanger is proportional to the discharge pressure and the discharge temperature decrease. The result is not much reduced.

Therefore, in order to control the temperature at the outlet pipe of the outdoor heat exchanger, the bypass solenoid valve 10 is used as the control temperature.
It is necessary to divide the control temperature according to the open / close state of. According to the characteristics of FIGS. 7 and 8, the discharge pressure is 3.04 MPa (about 30 kgf / cm ² G) when the bypass solenoid valve 10 is closed.
Hereinafter, in order to suppress the discharge temperature to 120 ° C. or lower, it is necessary to set the temperature of the outdoor heat exchanger outlet pipe to about 60 ° C. or lower, and when the bypass solenoid valve 10 is open, the discharge pressure is 3.04 MPa (about In order to control the discharge temperature to 30 kgf / cm ² G) or less and the discharge temperature to 120 ° C. or less, it is necessary to set the outdoor heat exchanger outlet piping temperature to about 65 ° C. or less.

Therefore, in the air conditioner according to the second aspect of the present invention, the first set temperature is preset to 60 ° C. and the second set temperature is set to 65 ° C., and the outdoor heat detected by the temperature detecting means 11 is detected. The bypass solenoid valve 10 and the compressor 1 are controlled by the controller 12 by comparing the exchanger outlet pipe temperature with the first and second set temperatures.

The control operation of the bypass solenoid valve 10 during the cooling operation by the controller 12 is performed according to the flow chart shown in FIG. In the invention described in claim 2, the second set temperature (T2: 65 ° C.) and the second set temperature T3 are different from the embodiment of the invention set forth in claim 1.

When the outlet pipe temperature T of the outdoor heat exchanger 3 exceeds the first set temperature (T1: 60 ° C.) during the cooling operation,
By opening the bypass solenoid valve 10, the load on the compressor 1 is reduced, and when the bypass solenoid valve 10 is opened, the outlet pipe temperature T of the outdoor heat exchanger 3 is set to the second set temperature (T2: 65).
(° C), the compressor 1 is abnormally stopped.

When the outlet pipe temperature T of the outdoor heat exchanger 3 falls below the third set temperature with the bypass solenoid valve 10 open, the bypass solenoid valve 10 is closed to return to the original normal state.
This is because when the bypass solenoid valve 10 is opened, the load on the compressor 1 can be reduced, but the cooling capacity is slightly reduced and the operating efficiency is deteriorated. Therefore, the operating conditions are eased and the outdoor heat exchanger 3 is cooled. If the outlet pipe temperature T falls below a predetermined temperature and the bypass solenoid valve 10 is closed but the limit value of the allowable operating range of the compressor 1 is not exceeded, the bypass solenoid valve 10
This is for closing the to enable efficient driving. The third set temperature is lower than the first set temperature by a predetermined temperature.

With the above control, the cooling operation can be continued even if the suction temperature of the outdoor heat exchanger 3 rises by about 4 to 5 ° C. as compared with the conventional apparatus, and the operation on the high temperature side during the cooling operation can be continued. The range can be expanded.

In the above embodiment, the operating range of the compressor is expanded under the overload condition of the cooling operation, and the opening / closing timing of the bypass solenoid valve 10, that is, the allowable operating range limit of the compressor 1 is detected. Although it is performed by the outlet pipe temperature of the outdoor heat exchanger, it goes without saying that the operating range can be similarly expanded by directly detecting the discharge pressure or the discharge refrigerant temperature of the compressor and controlling the bypass valve.

Further, if the pipe temperature sensor used for defrosting detection or for the outdoor heat exchanger also serves as the temperature detecting means 11, the number of parts is not increased and the operating range can be expanded without increasing the cost. It is possible.

Further, in the above-mentioned embodiment, the capillary tube is described as an example of the throttle means, but the invention is not limited to this, and an expansion valve may be used.

[0068]

As described above, according to the present invention, the first preset temperature and the second preset temperature higher than the first preset temperature are preset in the control device, and the temperature is detected during the cooling operation. When the temperature detected by the means reaches the first set temperature,
Since the bypass solenoid valve is opened and the compressor is configured to be brought to an emergency stop when the temperature detected by the temperature detecting means reaches the second set temperature, the air conditioner is abnormally stopped even under the cooling overload condition. In addition, the operation range can be expanded without increasing the load on the compressor, and the cooling operation can be continued.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a refrigeration cycle of a first embodiment of an air conditioner according to the present invention, and particularly relates to the invention according to claim 1.

[Fig. 2] Fig. 2 is a diagram showing a limit operation characteristic under a cooling overload condition of the air conditioner of the first embodiment.

FIG. 3 is a characteristic diagram showing a relationship between an outdoor heat exchanger outlet pipe temperature and a compressor discharge pressure during a cooling operation of the air conditioner of the first embodiment.

FIG. 4 is a characteristic diagram showing a relationship between an outdoor heat exchanger outlet pipe temperature and a compressor discharge refrigerant temperature during a cooling operation of the air conditioner of the first embodiment.

FIG. 5 is a flowchart showing a control operation of the control device for the air-conditioning apparatus of the first embodiment.

FIG. 6 is a configuration diagram showing a refrigeration cycle of a second embodiment of the air conditioner according to the present invention, and particularly relates to the invention according to claim 2.

FIG. 7 is a characteristic diagram showing a relationship between an outdoor heat exchanger outlet pipe temperature and a compressor discharge pressure during a cooling operation of the air conditioner of the second embodiment.

FIG. 8 is a characteristic diagram showing a relationship between an outdoor heat exchanger outlet pipe temperature and a compressor discharge refrigerant temperature during a cooling operation of the air conditioner of the second embodiment.

FIG. 9 is a configuration diagram showing a refrigeration cycle of a conventional air conditioner.

[Explanation of symbols]

 1 Compressor 3 Outdoor Heat Exchanger 4 Capillary Tube 5 Indoor Heat Exchanger 7a, 7b, 8a, 8b, 8c, 8d Refrigerant Piping 9 Bypass Path 10 Bypass Solenoid Valve 11 Temperature Detection Means 12 Controller

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[Procedure amendment]

[Submission date] September 14, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Further, the bypass electromagnetic wave of the bypass circuit (9)
If the valve (10) is opened, the discharged refrigerant will be discharged both during cooling and during heating.
Indoor heat exchanger (5) in which is an evaporator, and outdoor heat exchange
It is supplied to the entrance of the vessel (3) and is called hot gas bypass.
It becomes a pass operation, and when cooling, the indoor heat exchanger that is an evaporator
By preventing freezing and reducing the evaporation capacity during heating,
The discharge pressure can be reduced. That is, during cooling
The suction pressure drops and the indoor heat exchanger is likely to frost.
Then, the bypass valve is opened to prevent frost formation.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

During heating, the room air temperature rises.
Or the air volume decreases due to filter clogging, etc.
When the discharge pressure becomes high, the bypass solenoid valve opens
It is intended to prevent the refrigerant pressure from rising.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (3)

[Claims] 1. A compressor for compressing a refrigerant, an outdoor heat exchanger for exchanging heat between the refrigerant and the outside air, an indoor heat exchanger for exchanging heat between the refrigerant and indoor air, and the outdoor unit. A throttle means for squeezing and expanding a high-pressure refrigerant liquefied by a heat exchanger or the indoor heat exchanger, and a refrigerant that sequentially connects the compressor, the outdoor heat exchanger, the throttle means, and the indoor heat exchanger. A pipe, a first bypass path connected from a high-pressure pipe on the discharge side of the compressor to a refrigerant pipe connecting the throttle mechanism and the indoor heat exchanger, a bypass solenoid valve arranged in the bypass path, The temperature detection means provided in the outlet pipe of the outdoor heat exchanger, the first set temperature and the second set temperature higher than the first set temperature are preset, and the temperature detection means of the temperature detection means is set during the cooling operation. The detected temperature has reached the first set temperature Said bypass solenoid valve is opened, the detected temperature is an air conditioner which is characterized in that and a control device for emergency stop of the compressor when it reaches the second predetermined temperature of the temperature detecting means when. 2. A compressor for compressing a refrigerant, an outdoor heat exchanger for exchanging heat between the refrigerant and the outside air, an indoor heat exchanger for exchanging heat between the refrigerant and indoor air, and the outdoor unit. A throttling means for throttling and expanding the high-pressure refrigerant liquefied by the heat exchanger or the indoor heat exchanger, and a refrigerant pipe for sequentially connecting the compressor, the outdoor heat exchanger, the throttling means, and the indoor heat exchanger. A second bypass path connected from the discharge high-pressure piping of the compressor to the suction low-pressure refrigerant piping; a bypass solenoid valve arranged in the bypass path; and an outlet piping of the outdoor heat exchanger. The preset temperature detection means, the first preset temperature and a second preset temperature higher than the first preset temperature, and the detected temperature of the temperature detector is set to the first preset temperature during the cooling operation. When it reaches, the bypass solenoid valve is opened. And, an air conditioner, characterized in that it comprises a control device for emergency stop of the compressor when the detected temperature of said temperature detecting means reaches a second predetermined temperature. 3. A compressor for compressing a refrigerant, an outdoor heat exchanger for exchanging heat between the refrigerant and the outside air, an indoor heat exchanger for exchanging heat between the refrigerant and indoor air, and the outdoor unit. A throttling means for throttling and expanding the high-pressure refrigerant liquefied by the heat exchanger or the indoor heat exchanger, and a refrigerant pipe for sequentially connecting the compressor, the outdoor heat exchanger, the throttling means, and the indoor heat exchanger. A second bypass path connected from the discharge high-pressure piping of the compressor to the suction low-pressure refrigerant piping; a bypass solenoid valve arranged in the bypass path; and detecting the discharge refrigerant temperature of the compressor. The temperature detection means, the first set temperature and the second set temperature higher than the first set temperature are preset, and the detected temperature of the temperature detection means reaches the first set temperature during the cooling operation. If the bypass solenoid valve is opened An air conditioner characterized in that it comprises a control device for emergency stop of the compressor when the detected temperature of said temperature detecting means reaches a second predetermined temperature.