JPS6332256A - Heat pump system - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a heat pump system,
More specifically, the present invention relates to a heat pump system having a heating overload control function for a compressor with variable compression capacity.

(Prior Art) In recent years, inverter type compressors are being adopted as compressors with variable compression capacity from the viewpoint of providing comfortable air conditioning and saving energy. In an air conditioner incorporating such a compressor, a specific example of a compressor drive control method during heating overload is disclosed in Japanese Patent Application Laid-Open No. 59-1191, for example.
For example, the method described in Publication No. 49 can be mentioned. In this method, a method is shown in which an overload condition is detected by a pressure increase in the refrigerant pipe, and the signal from a pressure switch that closes at a pressure higher than a set pressure is used as an overload signal to control overload of the compressor. It is something to do. When an overload signal occurs, the compressor's rotational speed is reduced to the minimum rotational speed, and after the overload signal is released, the compressor's rotational speed is returned to the original rotational speed. It is expected that the engine will be in an unstable state close to the overload level, so if the engine speed is returned to the original speed immediately, the engine will become overloaded again, and there is a risk that the overload process will be repeated again, resulting in a so-called hunting state. be. Therefore, a method has been proposed in which the rotational speed is first increased to one step lower than the original rotational speed, and after this state is continued for a certain period of time, the original rotational speed is returned. However, in the conventional method in which the rotational speed of the compressor is lowered to the minimum rotational speed when an overload is detected, the heating capacity is significantly reduced during that time, resulting in a significant loss of comfort.

Therefore, we have set multiple levels of overload detection levels, and in addition to the final processing level that requires the compressor to actually reduce its rotational speed to the minimum rotational speed or stop it, we have set up multiple levels of overload detection levels, as well as a final processing level that requires the compressor to actually reduce its rotational speed to the minimum rotational speed or stop it. Set the level at which it is determined that
A conceivable configuration is to generate an overload signal in advance and thereby shift to overload processing. The overload processing method at this time is to gradually reduce the rotation speed of the compressor from the rotation speed of the compressor at the time the overload signal was generated, and in this process perform a process that attempts to release the overload signal. be able to. In order to prevent hunting as described above, the compressor rotation speed at the time of the overload signal cancellation is maintained for a certain period of time, and then the rotation speed is returned to the original rotation speed, or the heating load is changed using the rotation speed at that time as the initial value. This is to return to follow-up control.

When such overload processing is performed, heating performance does not decrease significantly, and therefore, overload processing can be performed without significantly impairing comfort.

Incidentally, in the above air conditioner, in addition to the pressure signal in the refrigerant circuit, for example, a temperature signal of the heat exchanger is also monitored as a detection signal of an overload state. In other words, when a large difference arises between the set processing capacity of the heat exchanger that acts as a condenser or evaporator and the compression capacity of the compressor, the condensing temperature or evaporation temperature increases, and the heat exchanger temperature increases. I'll come. Therefore, by detecting the heat exchanger temperature, if it exceeds a set temperature, it is considered an overload and the compression capacity of the compressor is reduced.

(Problem to be Solved by the Invention) Recently, a single heat source heat exchanger is equipped with multiple indoor heat exchangers for air conditioning, and even user-side heat exchangers for hot water heating, bath heating, etc. Heat pump systems consisting of exchangers connected in parallel are being put into practical use. In such a multi-type heat pump system, the following problem arises when attempting to detect the temperature of the user-side heat exchanger and perform overload processing when the temperature exceeds a set temperature. This is a problem that occurs when some of the user heat exchangers are stopped and the stopped user heat exchanger adds a new operation request. The problem with No. 1 is that when the above-mentioned addition is performed, the temperature signal of the added usage-side heat exchanger may lead to overload processing almost at the same time as the addition. For example, in the case of heating operation in a multi-type air conditioner, in an indoor unit in a shut-down room, high-temperature discharged gas refrigerant from the compressor flows into the indoor heat exchanger. In order to prevent high-pressure liquid from remaining, a small amount of refrigerant is circulated without fully closing the flow control valve, which is an electric expansion valve or the like connected to the flow control valve. Meanwhile, the indoor fan attached to it has been stopped.

For this reason, the indoor heat exchanger while it is stopped accumulates heat from the high-temperature discharged gas refrigerant and becomes higher in temperature than when it is in operation. However, when the operation started, the indoor fan turned on.
Once the refrigerant is activated and the refrigerant begins to flow steadily, the temperature immediately returns to normal during operation, and this does not indicate any abnormality in the refrigerant circuit. Nevertheless, if this stopped indoor heat exchanger issues a new operation request and its temperature detection signal is input at the same time, if this exceeds the overload level, it will immediately shift to overload processing. This is how it turned out. Therefore, after a request for operation is made, the heating operation that meets the request is only performed after a series of overload processes, and there is a problem in that the immediate heating performance is impaired.

The second problem is that if a new operation request is added from a stopped indoor heat exchanger during overload processing, the additional load will continue to increase until the overload processing is completed. However, the problem is that the operation does not proceed in a manner commensurate with this, and therefore, the ability to warm up quickly is impaired. In other words, the overload generation special control controls the compressor with a compression capacity that roughly corresponds to the overall load on the indoor heat exchanger side during operation, and therefore some indoor heat exchangers are in an overload state. In most cases, there is not a large difference between the overall load of the internal heat exchanger and the compression capacity at that time, so if a new operation request is added during overload processing, In this case, the overload condition is considered to be resolved immediately, and on the contrary, it is necessary to increase the compression capacity to match the increase in load. However, conventionally, once the overload process is started, the control does not shift to a new control appropriate for the load until the guard process for a certain period of time, which is provided especially to prevent hunting, is completed.

Therefore, the first object of the present invention is to control the capacity of the compressor in response to the additional request without entering into unnecessary overload control when a new operational request is added, and thus to immediately warm up the compressor. The purpose of the present invention is to provide a multi-type heat pump system that can improve performance.

A second object of the present invention is to interrupt the overload control and prevent unnecessary overload control when a new operation request is added while performing overload control. Controls compressor capacity according to demand,
Therefore, it is an object of the present invention to provide a multi-type heat pump system that can improve instant heating.

(Means for Solving the Problems) Therefore, in the heat pump system of the first invention, as shown in FIG. It is a heat pump system formed by connecting a plurality of user-side heat exchangers 18, in which the compressor 1 is connected to the user-side heat exchanger 1 that requires operation.
In addition, each of the above-mentioned compressor drive control means is provided, including a steady state drive means 41 that is driven with a compression capacity commensurate with the required load of No. 8, and an overload drive means 42 that is driven to reduce the compression capacity when overloaded. Overload detection means 30 that detects overload of the heat exchanger 18 on the user side and generates an overload signal.
and a switching means 44 for switching each of the compressor drive control means 41 and 42, and by this switching means 44,
The drive of the compressor 1 is configured to be switched from the steady state drive means 41 to the overload drive means 42 when the overload signal is input to the switching means 44, and An input guard means 45 is provided for blocking input of the overload signal to the switching means 44 until a set time has elapsed from the time when an operation request was added from the exchanger 18 side.

Further, in this second invention, as shown in FIG. 1, a compressor 1 with variable compression capacity is provided, and a plurality of user-side heat exchangers 18 are connected to one heat source-side heat exchanger 8. A heat pump system comprising: a steady-state driving means 41 for driving the compressor 1 with a compression capacity commensurate with the required load of the user-side heat exchanger 18 that requires operation; Overload drive means 42 to drive
and a fixed guard drive means 43 that is driven to maintain compression capacity when overload is released, and detects overload of each of the user-side heat exchangers 18 and outputs an overload signal. An overload detection means 30 that generates a
When the overload signal is input to the switching means 44, the drive of the compressor 1 is changed from the normal driving means 4 to the overload driving means 42, and then the overload signal is released. When the fixed guard driving means 43
After that, when a set time elapses, the drive is switched back to the drive by the steady-state drive means 41, and furthermore, during the drive by the fixed guard drive means 43, the drive from the user-side heat exchanger 18 is A forced return means 46 is provided for generating a fixed guard stop signal for switching to driving by the steady state drive means 4 when an operation request is added, and inputting this to the switching means 44;
An input guard means 45 is provided for blocking input of the overload signal to the switching means 44 until a set time has elapsed from the time when an operation request was added from the user side heat exchanger 18 side.

(Function) In the first invention, when an operation request is added from the user side heat exchanger 18 side, even if an overload signal is generated within a set time from this time, this input guard means 45, and is not input to the switching means 44. Therefore, depending on the transient temperature state immediately after the operation of the user-side heat exchanger 18 that has been stopped, the capacity of the compressor 1 is controlled in accordance with the increase in demand without shifting to overload processing. Immediate warming can be improved.

Further, in the second invention, when an operation request is added from the user side heat exchanger 1st side during overload processing, the fixed guard stop signal is generated by the forced return means 46,
As a result, the guard control by the fixed guard drive means is interrupted and the drive by the steady state drive means 41 is resumed. Moreover, at this time, the detection signal of the transient temperature state immediately after the start of operation of the user-side heat exchanger 18, which has been stopped, is blocked by the input guard means 45, and there is no new transition to overload processing. Since the capacity of the compressor 1 is controlled in accordance with the increase in demand, it is possible to improve the ability to warm up quickly.

(Example) Next, a heat pump system of the present invention will be described in detail using an air conditioner as an example with reference to the drawings.

First, Figure 2 shows a refrigerant circuit diagram of a multi-model air conditioner equipped with four indoor units.
1 indicates an outdoor unit, and A to D indicate the first to fourth indoor units, respectively. The outdoor unit X has a compressor 1
The compressor 1 has a capacity controlled by an inverter 2, and its discharge pipe 3 and suction pipe 4 are connected to a four-way switching valve 5. A first gas pipe 6 and a second gas pipe 7 are respectively connected to the four-way switching valve 5, and an outdoor heat exchanger 8 serving as a heat source side heat exchanger is connected to the second gas pipe 7. There is. Note that an outdoor fan 9 is attached to the outdoor heat exchanger 8. The outdoor heat exchanger 8 also includes a first liquid pipe 10, a liquid receiver 11, a second liquid pipe 1
2 are connected in sequence, and a first electric expansion valve 13 is interposed in the first liquid pipe 10. The second liquid pipe 12 is connected to a header 14, and from this header 14, a plurality of (in the case of the figure, four) downstream branch pipes 15...15 are branched. . . 15 are respectively provided with second electric expansion valves 16 . . . 16 . On the other hand, from the first gas pipe 6, there are also four gas side branch pipes 1 corresponding to the above.
7, . . 17 are branched, and indoor heat exchangers 18, . . . 18, which serve as user-side heat exchangers, are connected between the branch pipes 15, 17. Note that an indoor fan 19 is attached to each indoor heat exchanger 18, and both 18 and 19 constitute an indoor unit AD. Further, the liquid receiver 11 and the suction pipe 4 of the compressor 1 are connected by a pipe 20, and a capillary tube 21 is interposed in the pipe 20. In the figure, 22 represents a gas shutoff valve, 23 represents a liquid shutoff valve, 24.25 represents a muffler, and 26 represents an accumulator. In the above air conditioner, as shown by the solid line arrow in the figure, the refrigerant discharged from the compressor 1 is transferred from the outdoor heat exchanger 8, which serves as a condenser, to the indoor heat exchangers 18, which serve as evaporators. Cooling operation is performed by circulating the refrigerant, and conversely, heating is performed by circulating the refrigerant discharged from the compressor 1 from the indoor heat exchanger 18, which serves as a condenser, to the outdoor heat exchanger 8, which serves as an evaporator. The vehicle is operated (dashed line arrow in the figure).

In the above refrigerant circuit, each indoor unit A-D
A temperature sensor 30 for detecting the temperature of the indoor heat exchanger 18 is attached to each of the indoor heat exchangers 18, and an overload state is detected based on the detected temperature.

FIG. 3 shows a block diagram of the control system of the air conditioner. As shown in the figure, the outdoor Uniso+-X connects the outdoor control device 35,
Further, each of the indoor units A to D has an indoor control device 36, respectively. The indoor control device 36 is connected to an operation switch 37, an indoor thermostat 38, and the temperature sensor 30 serving as an overload detection means. There are two signals, namely: ■ an operation command signal issued when the operation switch 37 is ON and the room temperature has not reached the set temperature;
When the temperature detected by the temperature sensor 30 exceeds the overload level described later and the operation command signal is issued, an overload signal is output, respectively. It looks like this.

On the other hand, the outdoor control device 35 includes a load capacity value grasping section 39 that grasps the total load capacity value ΣS of the indoor unisol l-A-D with the above-mentioned operation command as an operation request signal from the indoor heat exchanger 18 side; Indoor UNISO with operation command) A, -D
Temperature difference detection unit 40 that calculates ΣΔT by integrating the ΔT times signal of
and a steady-state drive control section 4 that serves as a steady-state drive means that controls the frequency of the inverter 2 based on ΣS and ΣΔT.
1. In addition to the steady state drive control section 41 for performing the steady operation, the outdoor control device 35 includes:
Furthermore, it has an overload drive section 42 that serves as an overload drive means for controlling the compressor drive when an overload occurs, and a fixed guard drive section 43 that serves as a fixed guard drive means. Each of the above compressor drive control sections 41, 42, 43
It has a switching circuit 44 that serves as a switching means for switching based on an overload signal and an operation command signal. By this switching circuit 44, each of the compressor drive control sections 41, 42, 4
3 is alternatively selected, its output is given to the inverter 2, and the drive motor 1a of the compressor 1 is frequency-controlled;
The capacity of the compressor 1 is controlled. The overload signal for performing the switching operation of the switching circuit 44 is as follows:
The signal is input to the switching circuit 44 via an input guard section 45 serving as input guard means. The input guard section 45 includes:
A signal indicating an increase in the number of rooms that is output when there is an increase in the number of operation commands is input from the load capacity value grasping section 39, which grasps the presence or absence of operation commands from each indoor control device 36. This signal for increasing the number of rooms is also input to a forced return unit 46, which serves as a forced return means, and as will be described later, the output thereof also causes the switching circuit 44 to switch.

In the control circuit having the above configuration, the steady-state drive control of the compressor 1 will first be explained.

In the outdoor control device 35, as mentioned above, based on the model code signal output from each indoor control device 36, the load capacity grasping section 39 calculates the sum of the indoor unicycles (A-D) with operation commands. The load capacity ΣS is determined by the following procedure. First, the model code signal output from the indoor control devices 36...36 is determined according to the capacity of each indoor heat exchanger 18, and is, for example, 2240 kcal.
For the capacity of / h, the code of rooo J is 2
root J for 800kcal/h, 3550kc
a l/h has rolo J, also 4500kc
A code called roll J is defined for al/h, and these codes are stored for each indoor unit A to D. In addition, in the load capacity grasping section 39, the storage section 47 stores the load capacity value S corresponding to the above-mentioned model code. This load capacity value S is the capacity W224
0 kcal/h (model code rooo J) is set as the standard value "1", and 2800 kcal/h (model code r
00] J) to rl, 25J, 3550kcal/
h (model code r010 J) to rl, 5 J, 4500kcal/h (model code r011 J
) is set to "2", and the load capacity grasping circuit 48 reads out the load capacity value S for each indoor unit (A-D) with an operation command, and calculates the sum ΣS of these values. That's what I do.

In the outdoor control device 35, the total load capacity value ΣS of the indoor units A-D with the operation command is grasped as described above, and the difference between this and the room temperature and the set temperature determined by the indoor thermometer 38 is determined. The frequency of the compressor 1 is controlled by the steady-state drive control section 41 based on the corresponding signal ΣΔT. That is, an initial setting frequency corresponding to the above ΣS and ΣΔT is stored, and operation is performed at the above-mentioned initial setting frequency at the start of operation and when the number of operating rooms is increased, and after a predetermined period of time, P is set based on ΣΔT. The frequency is changed by control, PID control, etc. (Hereinafter, such control by the steady state drive unit 41 will be abbreviated as PID control.) Therefore, for example, if there are many indoor units I-A-D that have operation commands, the total load capacity value ΣS will generally increase, and in this case, the compressor 1 will be driven at a high frequency, thereby increasing the air conditioning capacity. This allows each room to be air-conditioned at the same time with the capacity that meets the demand.

Next, control when an overload signal is generated will be explained.

The compressor 1 is set to P by the steady-state drive control unit 41 as described above.
During heating operation under ID control, an amount of refrigerant that exceeds the condensation processing capacity of one indoor heat exchanger 18 in operation flows, and the condensation temperature rises, causing the safe operating temperature to rise. If the temperature exceeds a preset temperature, it is necessary to stop the operation of the compressor or reduce the compression capacity to reduce the amount of circulating refrigerant. Therefore, in the above embodiment, when the temperature of the indoor heat exchanger during operation exceeds 65°C, the compressor 1 is stopped, and before that, the PID control is stopped when the temperature exceeds 54°C. Control is performed to reduce the compression capacity. That is, 54° C. is set as an overload level, and when the temperature detected by the temperature sensor 30 exceeds this level, an overload signal is output from the indoor control device 36. In response to this signal, the switching circuit 44 switches the drive of the compressor to frequency droop control by the overload drive section 42.

In this frequency drooping control, control is performed to reduce the frequency at the time of switching at a rate of, for example, 802/min. This control is continued until the overload signal is released. Through this process, immediately after the overload signal is released, the PID
When the control is restored, the refrigerant circuit system is still in a state close to an overload state, so there is a risk that it will quickly re-enter the overload state and cause hunting that will require overload control again. After the overload signal is released, guard processing is performed to wait for the system to stabilize. That is, the compressor 1 is driven by the fixed guard drive section 43, and the frequency at which the overload is released is maintained for a set period of time (e.g., 8 minutes).
Continue this. Thereafter, the drive of the compressor 1 is switched to the steady-state drive control section 41, and normal operation under PI[l control is resumed.

In the air conditioner of the above embodiment, when performing the overload processing, the indoor heat exchanger 18 that is stopped is
In order to prevent transition to overload processing due to the transient temperature state when a new operation command signal is generated from In order to interrupt the heating and improve immediate heating, an input guard section 45 and a forced return section 46 are provided.
Control as shown in the flowchart of FIG. 4 is performed.

First, at the start of operation, the drive of the compressor 1 is initially set by the switching circuit 44 to be driven by the steady-state drive control unit 41 (step S1), and the total load capacity value ΣS of the indoor unit (indoor side unit) A-D with the above-mentioned operation command is set. Then, the initial frequency is set based on the total value ΣΔT of the difference between the room temperature and the set temperature, and after a certain period of time, PID control is started in accordance with the change in ΣΔT (step S2). Then, the above PID control is continued (steps 82 to S4) while determining whether an overload signal is input (step S3) and whether an operation request is added (step S4). During the above operation, for example,
If the room temperature reaches the set value in the room in operation (thermo is turned off), the operation command signal from the indoor control device in this room is stopped, and the number of rooms in operation at this time is In response to the accompanying decrease in the total load capacity value ΣS, a new lower frequency initial value is initialized, and thereafter frequency control is similarly performed in accordance with the ΣΔT signal.

If the thermostat is turned on and a new operation command signal is generated in a room that was stopped due to the thermostat being turned off, or if the operation switch of a room that had not been heated until then is turned on and an operation command signal is added, Step S
4, the process moves to step S5.

Steps S4 to S36 are performed by the input guard section 4 described above.
In step 5, PID control is continued (step S5) until the set time Tif (for example, 10 seconds) has elapsed (step S6) without determining whether an overload signal has been input. At this time, due to the increase in the number of rooms, ΣS, Σ
P from the new initial frequency for each change of ΔT
Control is being performed to shift to ID control. And Ti
After f has elapsed, the process returns to step S2 and continues PID control while determining the input of the overload signal.

Next, if an overload signal is input during the above operation,
Moving from step S3 to step S7, the switching circuit 4
4, the driving body of the compressor 1 is switched to be driven by the overload control unit 42, and the frequency droop control described above is performed until the overload signal is released (steps S8 and S9). After the overload signal is released, the drive of the compressor 1 is switched to the fixed guard drive section 43 (step 510), and the frequency fixed control that maintains the inverter frequency at the time of switching is performed until the guard time 'rgf (for example, 8 minutes) has elapsed. will continue until (
Step S11.513). During this time, it is determined whether a driving request is to be added (step 512). If no operation request is added and the guard time Tgf has elapsed, the drive of the compressor 1 is switched to the steady state drive control unit 41 in step S14, and then the process returns to step S2 and the above-mentioned P
Return to ID control.

The above step S12 is a step that functions as the forced return section 43, and if an operation request is added while the above fixed frequency control is being performed, the elapse of the set time Tgf of the above fixed frequency control is performed. without waiting,
This is interrupted and the process moves to step S15, where the steady state drive control section 41 switches to the compression t81 drive. Note that at this time, the temperature of the indoor heat exchanger that had been operating up until then was close to the overload signal level, and therefore the temperature of the indoor heat exchanger that had been stopped at this time was the same as above. There is a high possibility that the overload signal level has been exceeded. Therefore, in order to prevent the detected temperature of the transient temperature state at the start of operation from being input as an overload signal due to the addition of this stopped indoor heat exchanger, the process is moved from step S15 to step S5, and the input described above is performed. The process returns to step S2 via the function of the guard section 45 (step S5, Sfl+) to restore normal operation.

Note that in the above flowchart, steps S8 and S
If an operation request is added during the frequency droop control in step 9, the overload state will be canceled almost simultaneously due to the increase in the load capacity of the heat exchanger on the user side due to this addition, and steps SIO and SLL will perform each execution. and step S1
2, step S1 is performed by additionally inputting the operation request.
5, and is essentially step Sll.
Instead of fixed frequency control, PID control corresponding to the increase in load is immediately executed, and immediate heating performance is improved. Additionally, if the indoor heat exchanger temperature rises further during the above-mentioned overload processing and reaches the final set temperature of 65°C, an interrupt signal is input from the indoor control device 36, and at this time the compressor is turned off. It is made to stop.

The above embodiment includes both the first invention and the second invention, but the characteristic part of the first invention is that the temperature of the indoor heat exchanger when it is stopped is higher than the temperature when it is in operation. Focusing on the state in which this indoor heat exchanger is newly added, it is possible to shift to overload processing using the detected temperature signal of the temperature transient state at the start of operation as an overload signal. To prevent this, we have provided a means to cut off the overload signal input for a certain period of time when additional operations are added.
The capacity of the compressor 1 is controlled in accordance with the increase in demand without falling into unnecessary overload processing, and prompt heating performance is improved.

In the second invention, when a new operation of the indoor heat exchanger that has been stopped is added during overload processing, the load on the indoor heat exchanger side is naturally greater than the capacity of the compressor up to that point. It is considered that the overload condition will be released at that point, so the above-mentioned indoor heat An input cutoff means is provided for not accepting a detected temperature signal of a temperature transient state during additional operation of the exchanger as an overload signal. This prevents the continuation of unnecessary overload processing and re-entry, and controls the capacity of the compressor 1 in accordance with the increase in demand, improving quick warming performance.

In addition, in the above example, an example was shown in which an inverter-type multi-type air conditioner was used, but other devices having compression capacity control means, a hot water supply heat exchanger, a bath heating heat exchanger, etc. It can also be implemented in a connected heat pump system. Furthermore, in the above embodiment, the operation command signal issued when the operation switch is ON and the thermostat is ON is used as an example of the operation request signal. It can also be configured as a request signal. Also,
Although a temperature sensor attached to an indoor heat exchanger was used as an example of overload detection means, it is also possible to detect other overload conditions.
For example, it is also possible to configure it with a pressure sensor.

(Effects of the Invention) In the first invention, when the operation of the indoor heat exchanger is newly added, the detected temperature signal of the temperature transient state at the start of the operation is used as an overload signal to shift to overload processing. To prevent this from happening, we have provided a means to cut off the overload signal input for a certain period of time when additional operations are added.This allows us to control the compressor's capacity to meet the increased demand without falling into unnecessary overload processing. This can improve immediate heating.

Further, in the second invention, when a new operation of the stopped indoor heat exchanger is added during overload processing, the overload processing is forcibly interrupted and the compressor 1 is adjusted to meet the required load.
In addition to means for shifting to capacity control, input cutoff means is provided for not accepting a detected temperature signal of a temperature transient state at the time of additional operation of the indoor heat exchanger as an overload signal.

This prevents the continuation of unnecessary overload processing and re-entry, and controls the capacity of the compressor in accordance with the increase in demand, thereby improving the ability to warm up quickly.

[Brief explanation of the drawing]

The figures show an embodiment of the heat pump system of the present invention, in which Fig. 1 is a functional system diagram, Fig. 2 is a refrigerant circuit diagram, and Fig. 3 is a refrigerant circuit diagram.
The figure is a block diagram of the control system, and FIG. 4 is a flowchart of the control method. 1... Compressor, 8... Outdoor heat exchanger (heat source side heat exchanger), 18... Indoor heat exchanger (user side heat exchanger), 3
0... Temperature sensor (overload detection means), 41... Steady state drive control section (steady state drive means), 42... Overload drive section (overload drive means), 43... Fixed guard drive unit (fixed guard drive means), 44... switching circuit (
(switching means), 45... input guard section (input guard means), 46... forced return section (forced return means).

Claims (1)

[Claims] 1. It has a compressor (1) with variable compression capacity, and a plurality of user-side heat exchangers (1) in one heat source-side heat exchanger (8).
8), in which the compressor (1) is connected to a user-side heat exchanger (1) that requires operation.
The compressor drive control means includes a steady state drive means (41) that is driven with a compression capacity commensurate with the required load in 8), and an overload drive means (42) that is driven to reduce the compression capacity during overload. In addition, each of the above-mentioned user-side heat exchangers (18
) overload detection means (30) for detecting overload of the compressors (30) and generating an overload signal; and each compressor drive control means (4).
1) a switching means (44) for switching (42), and the switching means (44) controls the driving of the compressor (1) when the overload signal is input to the switching means (44). The system is configured to switch from the steady-state drive means (41) to the overload drive means (42) when an operation request is added from the user-side heat exchanger (18). A heat pump system comprising an input guard means (45) for blocking input of the overload signal to the switching means (44) until a set time elapses. 2. It has a compressor (1) with variable compression capacity, and a plurality of user-side heat exchangers (1) in one heat source-side heat exchanger (8).
8), in which the compressor (1) is connected to a user-side heat exchanger (1) that requires operation.
8) a steady state drive means (41) that drives with a compression capacity commensurate with the required load, an overload drive means (42) that drives to reduce the compression capacity during overload, and a compression capacity when the overload is released. fixed guard driving means (
43), and overload detection means (30) for detecting overload of each user-side heat exchanger (18) and generating an overload signal; A switching means (44) for switching the drive control means (41), (42), and (43) is provided, and this switching means (44) is provided.
4) changes the drive of the compressor (1) from the steady state drive means (41) to the overload drive means (42) when the overload signal is input to the switching means (44).
Then, when the overload signal is released, the drive is switched to the fixed guard drive means (43), and after that, when a set time elapses, the drive is switched back to the steady state drive means (41). and further to switch to driving by the steady-state drive means (41) when an operation request is added from the user side heat exchanger (18) while being driven by the fixed guard drive means (43). A forced return means (46) is provided which generates a fixed guard stop signal and inputs this to the switching means (44), and also when an operation request is added from the user side heat exchanger (18) side. A heat pump system comprising: input guard means (45) for blocking input of the overload signal to the switching means (44) until a set time elapses.