JP2000283574A - Refrigeration equipment - Google Patents

Abstract

(57) [Problem] To provide a refrigeration apparatus capable of controlling a proper refrigerant flow rate by detecting refrigerant discharge temperature, discharge pressure and input current of a compressor during overload operation. SOLUTION: A pair of bypass passages 14a and 14b communicating between the outside of a closed container of the compressor 3 and the compression chamber are provided, and outlets of the pair of bypass passages 14a and 14b are joined and connected to a bypass pipe 15.
The bypass pipe 15 and the outlet 4a of the condenser 4 are connected via a first on-off valve 16, and the bypass pipe 15 and the suction pipe 11 are connected to a second on-off valve 17
And a discharge temperature sensor 18 for detecting the discharge refrigerant gas temperature of the compressor 3, and the valve opening of the first on-off valve 16 in accordance with a change in the discharge refrigerant gas temperature detected by the discharge temperature sensor 18. The opening degree of the second on-off valve 17 is controlled in accordance with a change in the temperature of the evaporator temperature sensors 6a ', 6b', 6c 'for controlling and detecting the respective temperatures of the plurality of evaporators 6a, 6b, 6c. I did it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-type refrigeration system in which a plurality of indoor units are provided in one outdoor unit. More specifically, the present invention relates to the prevention of overload operation of a compressor and the prevention of an indoor unit. The present invention relates to a refrigerant circuit capable of performing a power save operation according to a load capacity.

[0002]

2. Description of the Related Art A conventional refrigeration system for forming a refrigerant circuit includes:
For example, as shown in FIGS. 2 and 3, the high-temperature and high-pressure refrigerant discharged from the compressor 31 flows in the direction of the solid line arrow, flows through the condenser 32, passes through the expansion valve 33, flows through the evaporator 34, and then compresses. It is constituted by a refrigerant circuit returning to the machine 31. The compressor 31 forms a plurality of compression chambers 10a and 10b in a closed vessel 7 by engaging a fixed scroll 8 having spiral wraps 8a and 9a and an orbiting scroll 9 to form a plurality of compression chambers 10a and 10b. A suction pipe 11 is connected to a suction port for sucking refrigerant gas into the compression chamber 10.
A discharge pipe 13 is connected to a discharge chamber 12 for discharging the refrigerant gas compressed at a, 10b. The discharge pipe 13 is arranged symmetrically with respect to the center of the fixed scroll 8 so that the outside of the closed container 7 and the compression chamber 10 are connected.
a, a pair of bypass paths 14a, 14b communicating with the
The bypass pipes 35 are provided by joining the outlets of the pair of bypass passages 14a and 14b, and the bypass pipes 35 and the outlets 32a of the condenser 32 are provided.
Are connected via an electronic expansion valve 36.

A discharge temperature sensor 37 for detecting a refrigerant gas temperature discharged from the compressor 31 and the electronic expansion valve in response to a change in the discharge refrigerant gas temperature detected by the discharge temperature sensor 37.
With the configuration including the first control unit 38 for controlling the opening degree of 36, when the discharge temperature rises during overload, part of the refrigerant liquefied at the outlet of the
Then, the refrigerant is injected into the compression chamber 10 of the compressor 31 to obtain a proper flow rate of the refrigerant, and the temperature of the discharged refrigerant gas can be kept constant.

However, in the above configuration, since the flow rate of the refrigerant is controlled only by the temperature of the discharged refrigerant gas, the compressor
There is a problem that it is not possible to control a change in the refrigerant flow rate due to a change in the refrigerant gas pressure discharged from the compressor 31 or a change in the input current of the compressor 31 due to power supply equipment or the like.

[0005]

DISCLOSURE OF THE INVENTION In the present invention, in consideration of the above problems, the discharge temperature of refrigerant of a compressor is detected,
Injects the liquid refrigerant of the condenser into the compression chamber according to the temperature, prevents overload operation of the compressor, maintains an appropriate refrigerant flow rate, and transfers refrigerant gas from the compression chamber to the suction pipe according to the load capacity of the indoor unit. Back,
An object of the present invention is to provide a refrigeration apparatus that can perform a power save operation.

[0006]

According to the present invention, in order to solve the above-mentioned problems, a compressor, a condenser and an expansion valve provided in an outdoor unit are sequentially connected to evaporators provided in a plurality of indoor units. A refrigerant circuit is formed, and the compressor forms a plurality of compression chambers in a closed container by interlocking a fixed scroll having a spiral wrap and an orbiting scroll, and sucks refrigerant gas into the compression chambers. A suction pipe is connected to a suction port to be connected, and a discharge pipe is connected to a discharge chamber that discharges the refrigerant gas compressed in the compression chamber. And a pair of bypass passages communicating with the compression chamber, a bypass pipe is provided by merging the outlets of the same pair of bypass paths, and the bypass pipe and the outlet of the condenser are connected via a first on-off valve. Along with
The bypass pipe and the suction pipe are connected via a second on-off valve, and a discharge temperature sensor for detecting a discharge refrigerant gas temperature is provided on the discharge pipe, while each of the plurality of evaporators is provided with:
An evaporator temperature sensor for detecting the temperature of the evaporator is provided, and when the discharge refrigerant gas temperature detected by the discharge temperature sensor rises by a predetermined value or more, a part of the liquid refrigerant at the outlet of the condenser according to the rise temperature. To inject into the compression chamber, control the valve opening of the first on-off valve, when the temperature of the evaporator detected by any of the evaporator temperature sensor rises above a predetermined value, the load decreases, The valve opening of the second on-off valve is controlled so that a part of the refrigerant gas in the compression chamber is returned to the suction pipe according to a load.

[0007] Further, the bypass passage communicates with a pair of compression chambers formed first between the spiral wraps.

[0008] Further, the bypass passage communicates with the outside of the side surface or the upper surface of the closed container.

Further, a temperature sensor having a small heat capacity is used as the discharge temperature sensor, and the discharge temperature sensor is provided near the compressor.

A pressure sensor for detecting the pressure of the refrigerant gas discharged from the compressor is provided in the discharge pipe, and the pressure sensor detects a change in the pressure of the discharged refrigerant gas detected by the pressure sensor and a rise in the temperature of the discharged refrigerant gas. Thus, the opening degree of the first on-off valve is controlled.

In addition, a current sensor for detecting an input current of the compressor is provided on a power supply line of a power supply for driving the compressor,
Changes in the compressor input current detected by the current sensor;
The opening degree of the first on-off valve is controlled in accordance with the rise in the temperature of the discharged refrigerant gas.

Further, the first and second on-off valves and the second on-off valve use an electronic expansion valve.

Further, the evaporator temperature sensor is provided near the inlet of each of the evaporators.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a refrigerant circuit diagram illustrating a multi-air conditioner dedicated to three-room cooling, and FIG. 2 is a cross-sectional view of a main part of a compressor. In the figure, 1 is an outdoor unit, 2a, 2b
And 2c are indoor units that can be operated simultaneously or arbitrarily. The high-temperature and high-pressure refrigerant discharged from the compressor 3 flows in the direction of the solid line arrow, flows through the condenser 4, passes through the expansion valve 5,
The refrigerant circuit is formed by branching and flowing through the respective evaporators 6 a, 6 b, 6 c, then joining and returning to the compressor 3.

The compressor 3 forms a plurality of compression chambers 10a and 10b in a closed container 7 by meshing a fixed scroll 8 having spiral wraps 8a and 9a and an orbiting scroll 9. A suction pipe 11 is connected to a suction port for sucking the refrigerant gas to 10a, 10b, and a discharge pipe 13 is connected to a discharge chamber 12 for discharging the refrigerant gas compressed in the compression chambers 10a, 10b. A pair of bypass passages 14a, 14b are provided symmetrically with respect to the center and communicate between the outside of the closed vessel 7 and the compression chambers 10a, 10b.
A bypass pipe 15 is provided by merging the outlets of the condenser pipe 14b and the bypass pipe 15 and the outlet 4a of the condenser 4 are connected via a first opening / closing valve 16, and the bypass pipe 15 and the suction pipe 11 are connected to a second pipe. On-off valve
Connect via 17.

A discharge temperature sensor 18 for detecting a refrigerant gas temperature discharged to the discharge pipe 13 of the compressor 3 and a discharge temperature sensor 18
The first on-off valve is configured such that, when the temperature of the discharged refrigerant gas detected by the above is increased by a predetermined value or more, a part of the liquid refrigerant at the outlet 4a of the condenser 4 is injected into the compression chambers 10a and 10b in accordance with the increased temperature. By controlling the valve opening degree of the 16th valve, the refrigerant gas control for suppressing the temperature rise of the compressor 3 during the overload operation of the indoor units 2a, 2b and 2c is performed, and the temperature is maintained at a constant level. A high refrigerant flow rate can be obtained.

The plurality of evaporators 6a, 6b, 6c are provided with evaporator temperature sensors 6a ', 6b', 6c 'for detecting respective temperatures, and the evaporator temperature sensors 6a', 6b ', 6c' detect the temperatures. Due to the change in the temperature of each of the evaporators 6a, 6b, 6c, the indoor units 2a, 2b, 2c
By controlling the valve opening of the second on-off valve 17 by capturing the load fluctuation of the operating condition of the above, a part of the refrigerant gas in the compression chambers 10a and 10b of the compressor 3 is transferred to the bypass pipe 15. Power save control can be performed by returning the suction pipe 11 to the suction pipe 11 through the suction pipe 11.

Further, the bypass passages 14a, 14b are formed by a pair of compression chambers 10a, 10a, which are formed first between the spiral wraps.
10b and the outside of the side surface or the top surface of the sealed container 7, the piping of the bypass pipe 15 can be simplified.

Further, by using a temperature sensor having a small heat capacity as the discharge temperature sensor 18 and being provided in the vicinity of the compressor 3, it is possible to improve the response of detecting the temperature of the discharged refrigerant gas.

The discharge pipe 13 is provided with a pressure sensor 19 for detecting the pressure of the refrigerant gas discharged from the compressor 3. The pressure sensor 19 detects a change in the pressure of the discharged refrigerant gas and a change in the temperature of the discharged refrigerant gas. The configuration in which the opening degree of the first opening / closing valve 16 is controlled in accordance with the rising temperature allows the refrigerant liquefied at the outlet 4a of the condenser 4 to change in accordance with the temperature of the discharged refrigerant gas pressure and temperature. Part of the bypass pipe
After being injected into the compression chambers 10a and 10b of the compressor 3 through 15,
Pressure control at the time of overload is performed, and the pressure is kept constant together with the temperature, so that an appropriate refrigerant flow rate can be obtained.

A current sensor 21 for detecting an input current of the compressor 3 is provided on a power supply line 20 of a power supply for driving the compressor 3.
And the valve opening of the first on-off valve 16 is controlled in accordance with a change in the input current of the compressor 3 detected by the current sensor 21 and a rise in the temperature of the discharged refrigerant gas. A part of the refrigerant liquefied at the outlet 4a of the condenser 4 is injected into the compression chambers 10a and 10b of the compressor 3 through the bypass pipe 15 in accordance with the input current and the temperature rise, thereby causing an overload. By controlling the current at the time, the current is kept constant with the temperature, and an appropriate refrigerant flow rate can be obtained.

The first on-off valve 16 and the second on-off valve
By using a configuration using an electronic expansion valve, the responsiveness of the opening degree of the valve is good, and fine adjustment of the refrigerant gas can be performed, and accurate capacity control can be performed.

The evaporator temperature sensors 6a ', 6b', 6c '
Is provided in the vicinity of the inlet of each of the evaporators 6a, 6b, and 6c, so that the responsiveness of the evaporator temperature detection can be improved, and the operation status of each indoor unit 2a, 2b, 2c can be quickly determined. Can be detected.

In the above configuration, the discharge temperature, discharge pressure, and input current of the refrigerant of the compressor 3 are detected, and each of the indoor units 2a, 2a,
When discharge temperature rise, pressure fluctuation and input current fluctuation occur during the overload operation of 2b and 2c, part of the refrigerant liquefied at the outlet 4a of the condenser 4 passes through the bypass pipe 15 and the compressor 3
By injecting the refrigerant into the compression chambers 10a and 10b, the discharge temperature, the discharge pressure, and the input current are stabilized, and an appropriate refrigerant flow rate can be obtained. Further, the evaporator temperature sensors 6a ', 6
b ', 6c' detects changes in the operating conditions of the indoor units 2a, 2b, 2c based on changes in the temperatures of the respective evaporators 6a, 6b, 6c detected by the evaporators 6a, 6b, 6c. A refrigeration apparatus capable of performing power save control by returning a part of the refrigerant gas in the compression chambers 10a and 10b of the compressor 3 to the suction pipe 11 via the bypass pipe 15. Becomes

[0025]

As described above, according to the present invention, the discharge temperature, discharge pressure and input current of the refrigerant of the compressor are detected, and the discharge temperature rise, pressure fluctuation and input current are detected when each indoor unit is overloaded. When fluctuations occur, a part of the refrigerant liquefied at the outlet of the condenser is injected into the compression chamber of the compressor through the bypass pipe, thereby stabilizing the discharge temperature, the discharge pressure and the input current, and adjusting the appropriate refrigerant flow rate. Obtainable. In addition, by changing the temperature of each evaporator detected by the evaporator temperature sensor, the load fluctuation of the operating condition of each indoor unit is captured, and the valve opening of the second on-off valve is controlled, so that the compressor By returning a part of the refrigerant gas in the compression chamber to the suction pipe via the bypass pipe, a refrigeration apparatus capable of performing power save control.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a compressor according to the present invention and a conventional example.

FIG. 3 is a refrigerant circuit diagram of a refrigeration apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outdoor unit 2a, 2b, 2c Indoor unit 3 Compressor 4 Condenser 5 Expansion valve 6a, 6b, 6c Evaporator 6a ', 6b', 6c 'Evaporator temperature sensor 7 Sealed container 8 Fixed scroll 9 Orbiting scroll 10a, 10b Compression chamber 11 Suction pipe 12 Discharge chamber 13 Discharge pipe 14a, 14b Bypass path 15 Bypass pipe 16 First open / close valve 17 Second open / close valve 18 Discharge temperature sensor 19 Pressure sensor 20 Power line 21 Current sensor

Claims (8)

[Claims] 1. A refrigerant circuit is formed by sequentially connecting a compressor, a condenser, and an expansion valve provided in an outdoor unit, and an evaporator provided in each of a plurality of indoor units, thereby forming a refrigerant circuit. A fixed scroll having a spiral wrap and an orbiting scroll are meshed with each other to form a plurality of compression chambers, and a suction pipe is connected to a suction port for sucking refrigerant gas into the compression chambers. A discharge pipe is connected to a discharge chamber that discharges compressed refrigerant gas, and the fixed scroll is provided symmetrically with respect to a center, and provided with a pair of bypass passages that communicate the outside of the sealed container and the compression chamber,
A bypass pipe is provided by merging the outlets of the pair of bypass paths, and the bypass pipe and the outlet of the condenser are connected via a first opening / closing valve, and the bypass pipe and the suction pipe are connected to a second opening / closing valve. And a discharge temperature sensor for detecting the temperature of the discharged refrigerant gas is provided on the discharge pipe, and an evaporator temperature sensor for detecting the temperature of the evaporator is provided for each of the plurality of evaporators. When the temperature of the discharged refrigerant gas detected by the temperature sensor rises by a predetermined value or more, the first opening / closing valve is opened so that a part of the liquid refrigerant at the outlet of the condenser is injected into the compression chamber in accordance with the temperature rise. When the temperature of the evaporator detected by any of the evaporator temperature sensors rises by a predetermined value or more and the load decreases, a part of the refrigerant gas in the compression chamber is transferred to the suction pipe according to the load. To return to
A refrigeration apparatus characterized by controlling a valve opening of the second on-off valve. 2. The refrigeration apparatus according to claim 1, wherein the bypass passage communicates with a pair of compression chambers formed first between the spiral wraps. 3. The refrigeration apparatus according to claim 1, wherein the bypass passage communicates with the outside of a side surface or an upper surface of the closed container. 4. The refrigerating apparatus according to claim 1, wherein a temperature sensor having a small heat capacity is used as the discharge temperature sensor, and the temperature sensor is provided near the compressor. 5. A pressure sensor for detecting a pressure of a refrigerant gas discharged from the compressor is provided in the discharge pipe, and the pressure sensor detects a change in the pressure of the discharged refrigerant gas detected by the pressure sensor and a rise in the temperature of the discharged refrigerant gas. The refrigeration apparatus according to claim 1, wherein the valve opening of the first on-off valve is controlled. 6. A current sensor for detecting an input current of the compressor is provided on a power line of a power input for driving the compressor, and a change in the compressor input current detected by the current sensor and a change in the discharge refrigerant gas temperature are detected. The refrigeration apparatus according to claim 1, wherein a valve opening of the first on-off valve is controlled in accordance with the temperature rise. 7. The refrigeration apparatus according to claim 1, wherein an electronic expansion valve is used for the first on-off valve and the second on-off valve. 8. The evaporator temperature sensor is provided near an inlet of each of the evaporators.
A refrigeration apparatus according to claim 1.