JP2664437B2 - Refrigeration equipment - Google Patents

Description

The present invention relates to a refrigerating apparatus in which a fixed capacity compressor and a variable capacity compressor are combined.

(B) Conventional technology A refrigeration system in which a fixed capacity compressor and a variable capacity compressor are connected in parallel, and the compressor, a condenser, a decompressor, and an evaporator are sequentially connected to form a refrigerant circuit. Is
No. 221349.

(C) Problems to be Solved by the Invention According to the device disclosed in the above-mentioned publication, when shifting from the independent operation of the variable capacity compressor to the simultaneous operation of the variable capacity compressor and the fixed capacity compressor, Since the rated output of the compressor was suddenly added, the total output from both compressors increased rapidly, and there was a problem that efficient operation corresponding to the cooling and heating load could not be performed.

The present invention provides a refrigeration apparatus that solves such a problem.

(D) Means for Solving the Problems The present invention provides a bypass path for returning a part of the refrigerant discharged from a constant capacity type compressor to the suction side of the compressor, and a constant capacity type provided in the bypass path. The refrigeration system includes a bypass valve that is closed later than the start of operation of the compressor, and a control unit that reduces the capacity of the variable capacity compressor when the constant capacity compressor starts operation and when the bypass valve is closed. It is like that.

(E) Operation When transitioning from single operation using the variable capacity compressor to simultaneous operation with the variable capacity compressor and the constant capacity compressor, the bypass valve remains for a while after the constant capacity compressor starts operating. By opening and guiding a part of the refrigerant discharged from this compressor to the low pressure side through the bypass pipe, the output of the constant capacity type compressor is reduced below the rated output, and the capacity of the variable capacity type compressor is reduced. After preventing the output from increasing suddenly, gradually reduce the capacity of this compressor, and then close the bypass valve and simultaneously reduce the capacity of the variable capacity compressor so that the output does not increase suddenly. After that, gradually increase the capacity of this compressor.

(F) Embodiment An embodiment of the present invention will be described with reference to FIG.
(1) is a constant capacity compressor with a rated output of 5 hp (2a)
And a variable capacity compressor (2b) having a minimum output of 2 hp and a maximum output of 5 hp by changing the operating frequency by the inverter device, an outdoor heat exchanger (3), and a gas-liquid separator (4). (5a) (5b) (5c) is an indoor unit having an indoor heat exchanger (6a) (6b) (6c) and having a capacity of 2 horsepower, 3 horsepower, and 5 horsepower. The exchanger (3) is branched and connected to the high-pressure discharge pipe (7) and the low-pressure suction pipe (8) of the compressor (2) through the switching valves (9a) and (9b), and is guided to the outdoor unit (1). The inter-unit piping (10) connecting the units (5a), (5b) and (5c) is branched and connected to a high-pressure gas pipe (11) branched and connected to a high-pressure discharge pipe (7) and a low-pressure suction pipe (8). Each of the indoor heat exchangers (6a) (6b) (6c) is composed of a low-pressure gas pipe (12) and a liquid pipe (13) connected to the outdoor heat exchanger (3). Tube (11) and the low pressure gas pipe (12) and the respective switching valve (14a) (15b), (14b)
(15b), (14c) and (15c) are branched and connected to the liquid pipe (13), and the refrigerant pressure reducer (16a) (1
6b) Connected via (16c).

(17) is a check valve provided on the discharge branch pipe (7a) of the constant capacity compressor (2a), and (18) is between the check valve (17) and the discharge side of the compressor (2a). One end is connected to the other end between the gas-liquid separator (4) and the compressor (2a).
As shown in the figure, when the constant capacity compressor (2a) is stopped, the bypass valve (19) and the capillary (20), which are closed later than the start of operation of the compressor (2a), are connected. Is provided.

(21) is control means for reducing the capacity of the variable capacity compressor (2b) at the start of operation of the constant capacity compressor (2a) and at the time of closing the bypass valve (19).

Next, the driving operation will be described. When cooling all the rooms at the same time, one of the switching valves (9a) of the outdoor heat exchanger (3) is opened, the other switching valve (9b) is closed, and the indoor heat exchanger (6) is closed.
a) One of the switching valves (14a) (14b) (14c) of (6b) and (6c)
By closing and switching the other switching valves (15a) (15b) (15c), the refrigerant discharged from the compressors (2a) (2b) discharges the discharge pipe (7), the switching valve (9a), and the outdoor heat exchange. Tableware (3)
And then condensed and liquefied here, then through the liquid pipe (13), the refrigerant pressure reducer (16)
a) Partitioned into (16b) and (16c), where the pressure is reduced. Then, after evaporating in each indoor heat exchanger (6a) (6b) (6c), switching valves (15a) (15b) (15c), low-pressure gas pipe (12), suction pipe (8), It is sucked into the compressors (2a) and (2b) sequentially through the gas-liquid separator (4). All the rooms are simultaneously cooled by the indoor heat exchangers (6a) (6b) (6c) acting as such evaporators.

Conversely, when heating all the rooms simultaneously, one of the switching valves (9a) of the outdoor heat exchanger (3) is closed and the other switching valve (9b) is opened, and the indoor heat exchangers (6a) (6b) (6c)
By opening one of the switching valves (14a) (14b) (14c) and closing the other switching valve (15a) (15b) (15c), the discharge from the compressors (2a) (2b) (2c) The refrigerant passes through the discharge pipe (7) and the high-pressure gas pipe (11) sequentially,
a) (14b) (14c), indoor heat exchangers (6a) (6b) (6c)
After being condensed and liquefied here, the refrigerant is decompressed by each of the refrigerant decompressors (16a), (16b) and (16c) and is joined by the liquid pipe (13), and thereafter, the outdoor heat exchanger (3) After being evaporated and vaporized in, it is sucked into the compressors (2a) and (2b) through the switching valve (9b), the suction pipe (8) and the gas-liquid separator (4) in that order. Thus, each indoor heat exchanger (6a) (6b) (6
In c) all rooms are heated simultaneously.

During the simultaneous cooling operation and the simultaneous heating operation, the bypass valve (19) is closed and the constant capacity type compressor (2a) operates at the rated 5 hp and the variable capacity type compressor (2b) operates at the maximum output of 5 hp. Have been.

For example, when only the indoor unit (5b) is operated to cool or heat only this one room, the variable capacity compressor (2b) has a capacity corresponding to 3 horsepower of the indoor unit (5b).
Is operating, and the constant capacity compressor (2a) is stopped. During such a single-chamber operation, the pressure is released through the capillary tube (20) so that the refrigerant pressure in the discharge branch pipe (7a) of the constant capacity compressor (2a) is not increased by opening the bypass valve (19). The check valve (17) prevents the discharge refrigerant pressure of the variable capacity compressor (2b) from being applied to the inside of the discharge branch pipe (7a). Therefore, the constant capacity type compressor (2a) The discharge vane opens and starts smoothly.

This activation is performed when the operation mode shifts from the single-room operation to the two-room operation and further to the all-room operation described above.
As shown in FIG. 2, the control signal from the bypass valve (1
9) Opening and guiding a part of the refrigerant discharged from the constant capacity compressor (2a) to the low pressure side through the bypass (18) until the required horsepower of the indoor unit reaches 7 hp, The output of the constant capacity compressor (2a) is reduced to 3 hp and the capacity of the variable capacity compressor (2b) is reduced to 2 hp so that the output does not increase suddenly. After increasing the capacity of (2b) and then closing the bypass valve (19) and reducing the capacity of the variable capacity compressor (2b) again to 2 hp to prevent the output from increasing rapidly, Gradually increase the capacity of the compressor (2b). Therefore, the operation of the variable capacity compressor (2b) starts from the isolated operation of the variable capacity compressor (2b).
The output does not fluctuate abruptly when shifting to simultaneous operation of b) and the constant capacity compressor (2a).

In order to simultaneously cool two rooms and heat one room at the same time, for example, one switching valve (9a) of the outdoor heat exchanger (3) is opened and the other switching valve (9b) is closed, and cooling is performed. One switching valve (14b) (14c) of the indoor unit (5b) (5c)
Is closed and the other switching valve (15b) (15c) is opened and one of the switching valves (14a) of the indoor unit (5a) for heating is heated.
When the other is opened and the other switching valve (15a) is closed, part of the refrigerant discharged from the compressors (2a) and (2b) passes through the discharge pipe (7) and the switching valve (9a) in order, and the outdoor heat exchanger ( 3) and the remaining refrigerant flows to the switching valve (14a) and the indoor heat exchanger (6b) of the indoor unit (5a) for heating via the high-pressure gas pipe (11), and this indoor heat exchanger (6a) And the outdoor heat exchanger (3). The refrigerant is condensed and liquefied in the heat exchangers (6a) (3) and passes through the liquid pipe (13), and the refrigerant pressure reducers (16b) (16c) of the indoor units (5b) (5c)
After being decompressed in each of the indoor heat exchangers (6b) and (6c), they are evaporated and vaporized. Thereafter, they are combined in each of the low-pressure gas pipes (12) through the switching valves (15b) and (15c), and are suctioned. (8) It is sucked into the compressors (2a) and (2b) sequentially through the gas-liquid separator (4). Thus, one room is heated by the indoor heat exchanger (6a) acting as a condenser, and two rooms are cooled by the other indoor heat exchangers (6b) (6c) acting as an evaporator.

At the time of the simultaneous cooling and heating operation, the bypass valve (19) is closed, and the operating capacity of the heating indoor unit (5b) is 2 horsepower and the total operating capacity of the cooling indoor units (5b) and (5c) is 8 Compared to the horsepower, the constant capacity compressor (2a) is operated at 5 hp and the variable capacity compressor (2b) is operated at 3 hp to match the larger 8 hp.

In both of the above embodiments, the unit-to-unit piping (10) is composed of three refrigerant pipes, a high-pressure gas pipe (11), a low-pressure gas pipe (12), and a liquid pipe (13). Under a simple circuit configuration using a heat exchanger, simultaneous cooling and heating operation of a plurality of indoor units can be freely selected and performed in any indoor unit as well as simultaneous cooling and heating operation, and In the simultaneous cooling and heating operation, the indoor heat exchanger acting as a condenser and the indoor heat exchanger acting as an evaporator are connected in series, so that efficient operation by heat recovery can be performed. It is not limited to only circuits.

Further, in the above embodiment, one end of the bypass path (18) is connected to the discharge branch pipe (7a) of the constant capacity compressor (2a) d. Instead, one end of the bypass path (18) is connected to the constant capacity compressor. The compressor (2a) may be connected to the intermediate discharge port of the compressor (2a). The variable capacity compressor (2b) has a multi-stage capacity such as a pole number conversion type or unloader type in addition to an inverter type whose operating frequency changes. It may be changed to.

(G) Effects of the Invention According to the present invention, when the independent operation of the variable capacity compressor is shifted to the simultaneous operation of the variable capacity compressor and the constant capacity compressor, the discharge refrigerant of the constant capacity compressor is controlled. Reduce the capacity of the variable capacity compressor at the same time as returning part of it to the suction side, and then stop returning some of the refrigerant discharged from the constant capacity compressor to the suction side, and at the same time reduce the capacity of the variable capacity compressor. I decided to lower it,
It is possible to prevent the total output from both compressors from fluctuating abruptly, and it is possible to perform an efficient operation corresponding to the cooling and heating load.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus showing an embodiment of the present invention,
FIG. 2 is an explanatory diagram showing an operation pattern of the compressor. (2a) ... Constant capacity compressor, (2b) ... Variable capacity compressor, (18) ... Bypass path, (19) ... Bypass valve,
(21) Control means.

Claims (1)

(57) [Claims] 1. A refrigerating apparatus in which a constant capacity compressor and a variable capacity compressor are connected in parallel, and a compressor, a condenser, a decompressor, and an evaporator are sequentially connected to form a refrigerant circuit. A bypass passage for returning a part of the refrigerant discharged from the constant capacity compressor to the suction side of the compressor, and a bypass provided in the bypass passage and blocked later than the start of operation of the constant capacity compressor. A refrigeration system comprising: a valve; and control means for reducing the capacity of the variable capacity compressor at the start of operation of the constant capacity compressor and at the time of closing the bypass valve.