JPH065566Y2 - Heat pump device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of operation control of a heat pump device in which two parallel compressors are provided in the same refrigerant circuit, particularly control when the discharge pressure rises. .

[Conventional technology]

A conventional device of this type is shown in FIG. In the figure, (1a), (1b) is a compressor, (2) is a switching valve, (3a), (3b)
Is an indoor heat exchanger, (4) is a decompressor, (5) is an outdoor heat exchanger,
(6) is an accumulator, (7) is an oil separator, (8) is an oil separator
This is a solenoid valve provided in a bypass path (9) from (7) to the accumulator (6), and the refrigerating machine oil separated by cyclic opening / closing control is returned to the compressor via the accumulator (6). (10a) and (10b) are discharge check valves, (11a) and (11b) are suction check valves, and (12) is a pressure detection device, which has a constant on / off pressure difference and operates when the pressure rises. The heat pump device is controlled.

In the figure, the solid line arrow indicates the refrigerant flow direction during heating, and the broken line arrow indicates the refrigerant flow direction during cooling.

Next, the operation will be described. During heating, the compressor (1
The high-temperature high-pressure gas refrigerant discharged from (a) and (1b) flows into the oil separator (7) through the discharge check valves (10a) and (10b), and the gas refrigerant is discharged in the oil separator (7). The refrigerating machine oil discharged together with it is collected, and the gas refrigerant is transferred to the indoor heat exchangers (3a), (3
b), heat is dissipated to the room air and heating is performed.
The refrigerant becomes a high-pressure liquid refrigerant and is decompressed by the decompression device (4),
The low-pressure gas-liquid mixed refrigerant is supplied to the outdoor heat exchanger (5), and heat is taken from the outdoor air to become a low-pressure gas refrigerant.
Flow into the accumulator (6) via (2), separate liquid refrigerant and gas refrigerant, only gas refrigerant suction check valve (11a), (11b)
Is sucked into the compressors (1a), (1b) via the. Further, during cooling, the high-temperature high-pressure gas refrigerant discharged from the compressors (1a) and (1b) passes through the discharge check valves (10a), (10b), the oil separator (7) and the switching valve (2). Flow into the outdoor heat exchanger (5) to exchange heat with the outdoor air to become high-pressure liquid refrigerant, which is decompressed by the decompression device (4) and taken from the indoor air by the indoor heat exchangers (3a) and (3b). While heating and cooling, it becomes a gas refrigerant and is sucked into the compressors (1a) and (1b) via the switching valve (2), the accumulator (6) and the suction check valves (11a) and (11b).

In the conventional heat pump device configured as described above, the indoor heat exchanger (3a), (3b) is performed capacity control operation to control the number of operating compressors according to the indoor air conditioning load FIG. 5 together with the control circuit diagram of the heat pump device shown in FIG. 4 for the specific content of the control when the discharge pressure rises when the two compressors (1a) and (1b) are operating together. It will be described based on the pressure control flowchart shown in FIG. In FIG. 4, reference numeral (20) in FIG. 4 is a microcomputer that controls the control, and includes a CPU (21), a memory (22), an input circuit (23), and an output circuit (24), and a memory ( It is configured to control the heat pump device according to the program incorporated in 22). Reference numeral (12a) is a contact of the pressure detecting device (12) shown in FIG. 2, and a pressure detection signal is given to the input circuit (23) through the series resistor (27). It should be noted that the input circuit (23) is supplied with inputs of temperature signals and the like (above, not shown) of the respective parts via the operation switch of the heat pump device, the heating / cooling changeover switch and the analog / digital converter. Further, (26) is an output circuit of the microcomputer (20).
The output signal from (24) has a buffer circuit (2
The control relay circuit is supplied via 5), and includes the compressor relays (31a) and (31b) and the solenoid valve relay (32). Specifically, the relays (31a), (31b),
The heat pump device is controlled by a control circuit in which the normally open contact point (32) is connected in series to each compressor electromagnetic contactor and electromagnetic valve coil (above, not shown).

FIG. 5 is a flow chart when the discharge pressure rises when two compressors (1a) and (1b) among the control programs stored in advance in the memory (22) are operating. 1
The flow for determining the number of operating units in a) and (1b) is located upstream of the flow part shown in FIG. 5, and the flow for periodically opening the solenoid valve (8) is located downstream of the flow part shown in FIG. Is configured to. In FIG. 5, in step (40), it is judged whether or not the discharge pressure exceeds a predetermined value by the contact (12a) shown in FIG. 4, and if it does not exceed the set value, the step (41) is followed. The solenoid valve (8) is closed, or the closed state is continued, and the process proceeds to step (42). In step (42), the number of operating compressors is determined, and if the number of operating compressors is other than one, the operation proceeds to step (43) to continue operating two compressors. When the number of operating compressors is one in step (42), the process proceeds to step (44) to temporarily stop all the compressors, and the number of compressors is switched to two in the next routine. . In other words, when only one of the compressors (1a) and (1b) is in operation, switching to simultaneous operation of two compressors causes the discharge part of the compressor (1a) or (1b) which has been stopped until then. Since the pressure difference with the suction part is too large and a large starting torque is required, it may not be possible to start the compressor.
It is necessary to temporarily stop all of steps a) and (1b) and balance the pressure, and then set the number of units in operation to two.

When the discharge pressure exceeds the predetermined value in step (40), the process proceeds to steps (45) and (46), the number of operating compressors is set to one, and the solenoid valve (8) is opened to discharge pressure. Suppress the rise of. The number of operating compressors is 1 due to steps (45) and (46).
If the discharge pressure falls below the set value due to the solenoid valve (8) opening, it becomes the step (40a).
From (41) to (42) to (44), the compressor is completely stopped, and the timer set when the pressure exceeds the set pressure in step (40) is reset. If the pressure is equal to or higher than the set value in step (40a), proceed to step (47).
It is determined whether or not the time counted by the timer set in (40) is a predetermined value (for example, 30 minutes) or more, and after the predetermined time has elapsed, the process proceeds to step (48) to completely stop the compressor. .

[Problems to be solved by the invention]

As described above, in the conventional heat pump device, the compressor (1
When both a) and (1b) are operating together, the discharge pressure rises and the pressure detection device (12) operates, which causes either compressor (1a) or (1b) to stop, After that, if the discharge pressure falls below the operating value of the pressure detection device (12), the compressor (1
All of a) and (1b) are stopped, and operation is restarted with the two compressors (1a) and (1b). Therefore, depending on the indoor / outdoor conditions of the heat pump device, there is a problem that the above-mentioned operation pattern is repeated very frequently, and the life of the compressors (1a), (1b),
As a result, there is a problem that the life of the heat pump device is significantly reduced. Further, as described above, since all the stop and all the operation modes are repeated, the air conditioning capacity is not sufficiently obtained, and the energy saving is deteriorated, and the two compressors (1a) and (1b) are used. There is also a problem that the original purpose of performing capacity control cannot be achieved.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a heat pump device capable of suppressing an increase in discharge pressure without repeating frequent start and stop.

[Means for solving problems]

In this invention, a plurality of compressors connected in parallel, a switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and a refrigerant circuit in which an accumulator is annularly pipe-connected, and the compressor. Oil separator provided between the discharge side and the switching valve, the bypass passage from the oil separator to the accumulator via the solenoid valve, and the discharge pressure of the compressor is set to a predetermined pressure. When the discharge pressure of the compressor is above the specified pressure value, the number of operating compressors is reduced. In addition, when the pressure is less than the predetermined pressure, the number of operating compressors is maintained at the plurality of compressors, or the compressor operating number controller for switching to the plural compressor operation after the compressor is completely stopped, and the pressure detecting device. Pressure of An output signal as an input, a solenoid valve control means for opening the solenoid valve when the discharge pressure of the compressor is equal to or higher than the predetermined pressure value and closing the solenoid valve when the discharge pressure is less than the predetermined pressure value, the compression Decrease the number of compressors in operation by measuring the compressor reduction operation time after the discharge pressure of the compressor exceeds the above specified pressure value and by increasing the discharge pressure of the compressor above the specified pressure value. In addition, after the solenoid valve is opened, the discharge pressure becomes less than a predetermined pressure value, and even when the solenoid valve is closed, the heat pump device is provided with timer means for continuing the reduction operation of the compressor for a predetermined time. To achieve the above object.

[Action]

The heat pump device according to this invention reduces the number of operating compressors when the discharge pressure of the compressor rises and becomes equal to or higher than a predetermined pressure value. Even when the discharge pressure becomes less than the predetermined pressure and the electromagnetic valve is closed, the compressor is kept operating while continuing to reduce the number of compressors. Therefore, frequent start and stop of the compressor can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a discharge pressure control flowchart of a heat pump device according to an embodiment of the present invention. FIG. 2, FIG. 3, and FIG. 4 are an overall configuration diagram, a control block diagram, and a main part control circuit diagram of the heat pump device, respectively.

In FIG. 3, (12) is a pressure detecting device for detecting whether the discharge pressure of the compressor is equal to or higher than a preset predetermined pressure value, (102) is provided with indoor heat exchangers (3a), (3b) The number of operating compressors (1a), (1b) is controlled according to the indoor air-conditioning load, and the number of operating compressors (1a), (1b) is controlled when the discharge pressure is equal to or higher than a predetermined pressure value. This is a means for controlling the number of operating compressors to be one. (103) is an electromagnetic valve (8) that opens the solenoid valve (8) to periodically return the refrigeration oil collected in the oil separator (7) to the accumulator (6). Solenoid valve control means for opening (8) and closing the solenoid valve (8) when the pressure is less than a predetermined pressure, (104) is set when the number of operating compressors is one, the compressor (1a), (1
It is a timer means for measuring the cumulative operation time of b). (Ten
Reference numeral 5) is a control output unit that controls the operation of each device of the heat pump device according to each of the control units (102) to (104).

In this embodiment, in the refrigerant circuit shown in FIG.
(1a), the discharge pressure of (1b) is more than a predetermined pressure value set in advance, provided with a pressure detection device (12) for detecting whether or not,
When the output signal of this pressure detection device (12) is input and the discharge pressure of the compressors (1a), (1b) is above the predetermined pressure value, the compressor operating number control means (102) causes the compressor Control the increase or decrease of the discharge pressure of the compressor by opening the solenoid valve (8) provided in the bypass line (9) and operating the single unit of (1a) or (1b) I do. On the other hand, the timer means (104) is used as an input to the pressure detection signal of the pressure detection device (12) to measure the operating time of one compressor after the discharge pressure of the compressor becomes equal to or higher than a predetermined pressure value, And when the number of operating compressors is 1 and the solenoid valve (8) is opened as described above, the discharge pressure of the compressor becomes less than a predetermined value and the solenoid valve (8) is closed. However, it is configured such that the operation of one of the compressors can be continued for a predetermined time.

In FIG. 1, in step (40), the pressure detection device showing in FIG. 4 whether or not the discharge pressure of the compressor exceeds a predetermined value.
When it is detected by the contact (12a) of (12) and the pressure is less than the preset pressure value, the step (4
Continue to operate the two compressors (1a) and (1b) via 1), (42) and (43). In step (42), the number of operating compressors is 1
In the case of a table, it is determined in step (50) whether or not the time counted by the timer means set in step (40) is a predetermined time or more.
Go to the “O” side, and the timer judgment in step (50) is “Y
The above state is continued until it becomes "ES". When the predetermined time has elapsed, the process proceeds to step (51), the above-mentioned timer means is reset, and the compressor is completely stopped.

When the discharge pressure becomes equal to or higher than the predetermined pressure value in step (40), the process proceeds to steps (45) and (46) to set the number of operating compressors to one and open the solenoid valve (8). Suppress the rise in discharge pressure. It should be noted that if the discharge pressure continues to be equal to or higher than a predetermined value and one unit is operated for a predetermined time, it will stop at steps (47) and (48). Further, by the control as described above, in step (40a), when the discharge pressure is reduced to less than the predetermined pressure value and the contact (12a) of the pressure detection device (12) is opened, the steps from step (40a) to step (40a) are performed. Proceed to (41), the solenoid valve (8) is closed, and proceed to step (42). Since the number of operating compressors is one, the process proceeds to step (50), and the timer means (104) set when the contact (12a) is closed in step (40).
If the time has not expired, the step proceeds to the judgment “NO” side, and the state is continued until the timer judgment in step (50) becomes “Yes” while the operation of one compressor is continued. If the discharge pressure rises in the state and it proceeds to the step (45) side, continue operating one compressor and open the solenoid valve (8) in step (46) to raise the discharge pressure. Control to suppress.

[Effect of device]

In this invention, a plurality of compressors connected in parallel, a switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and a refrigerant circuit in which an accumulator is annularly pipe-connected, and the compressor. Oil separator provided between the discharge side and the switching valve, a bypass path from the oil separator to the accumulator via an electromagnetic valve, and the discharge pressure of the compressor is set to a predetermined value. Pressure detection device for detecting whether or not the pressure value or not, and the pressure detection signal of this pressure detection device as an input, and when the discharge pressure of the compressor is the predetermined pressure value or more, the number of operating compressors When the compressor operating number control means that decreases and the pressure detection signal of the pressure detection device are input, when the discharge pressure of the compressor is equal to or higher than the predetermined pressure value, the solenoid valve is opened and less than the predetermined pressure value. When The electromagnetic valve control means for closing the electromagnetic valve, and the pressure detection signal of the pressure detection device as an input, and measures the compressor decreasing operation time after the discharge pressure of the compressor becomes equal to or higher than the predetermined pressure value, And, since the discharge pressure of the compressor rises above a predetermined pressure value, the number of operating compressors is reduced and the solenoid valve is opened, after which the discharge pressure becomes less than the predetermined pressure value, and the solenoid valve is Even if the circuit is closed, the heat pump device is configured by providing the timer means for continuing the compressor reducing operation for a predetermined time, so that the compressor does not start and stop more frequently than necessary, and the life of the compressor is reduced. Can be made longer. Further, since the compressor does not frequently start and stop, the air conditioning capacity does not decrease due to the start and stop, so that there is an effect that an operation with high energy efficiency can be achieved.

[Brief description of drawings]

FIG. 1 is a flow chart of pressure control in a heat pump device according to an embodiment of the present invention, FIG. 2 is an overall configuration diagram of a conventional general heat pump device, and FIG. 3 is a control block of a heat pump device according to an embodiment of the present invention. FIG. 4 and FIG. 4 are control circuit diagrams of the main part of the conventional general heat pump device, and FIG. 5 is a pressure control flowchart of the conventional heat pump device. In the figure, (1a). (1b) is a compressor, (2) is a switching valve, and (3a).
(3b) Indoor heat exchanger, (4) Decompression device, (5) Outdoor heat exchanger, (6) Accumulator, (7) Oil separator, (8) Installed in bypass (9) Solenoid valve, (12) is a pressure detection device,
(102) is a compressor operating number control means, (103) is a solenoid valve control means, and (104) is a timer means. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] 1. A refrigerant circuit in which a plurality of compressors connected in parallel, a switching valve, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, and an accumulator are annularly pipe-connected, and the compressor. An oil separator provided between the discharge side and the switching valve, a bypass path from the oil separator to the accumulator via a solenoid valve, and the discharge pressure of the compressor is a preset pressure value or more. Whether the pressure detection device to detect whether or not, the pressure detection signal of the pressure detection device as an input, when the discharge pressure of the compressor is above the predetermined pressure value, while reducing the number of operating the compressor, When the pressure is less than the predetermined pressure, the number of operating compressors is maintained at the plurality of compressors, or the compressor operating number control means for switching to the operation of the plurality of compressors after the compressor is completely stopped, and the pressure detection signal of the pressure detecting device. And enter , A solenoid valve control means for opening the solenoid valve when the discharge pressure of the compressor is equal to or higher than the predetermined pressure value and closing the solenoid valve when the discharge pressure is less than the predetermined pressure, and the discharge pressure of the compressor is By measuring the compressor decreasing operation time after reaching the predetermined pressure value or more and increasing the discharge pressure of the compressor to the predetermined pressure value or more, the number of operating compressors is reduced and the solenoid valve is used. The heat pump device is provided with a timer means for continuing the reduction operation of the compressor for a predetermined time when the discharge pressure becomes less than a predetermined pressure value and the electromagnetic valve is closed after the circuit is opened.