JPH02282662A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable an abnormal increasing of a pressure of refrigerant to be avoided by a method wherein a flow rate control means capable of adjusting a flow rate of refrigerant flowing between a heat exchanger at a heating source side and another heat exchanger at a utilization side is provided and an amount of circulating refrigerant within a main refrigerant circuit is decreased by side flow rate control means. CONSTITUTION:A main refrigerant circuit 10 is provided, wherein a plurality of indoor devices A, B... having a main pressure reducing mechanism 6 and a heat exchanger 7 at a utilization device are connected in parallel by a refrigerant pipe 9 in respect to an outdoor device X having a compressor 1, a heat exchanger 3 at a heating source and a liquid receptor 5. With the aforesaid configuration, a pressure detecting means 53 may detect a high pressure of a refrigerant pressure and then an output signal from the pressure detecting means 53 is sent to a comparing means 54. The comparing means 4 compares a predetermined reference pressure at a high pressure side with a high pressure of the refrigerant pressure and as the high pressure of the refrigerant pressure is more than the reference pressure, the output signal from the comparing means 54 is sent to a flow rate control means 60 and then a flow rate control means 60 may control a flow rate adjusting means 52 so as to cause a circulating amount of refrigerant to be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air conditioner, and in particular, to measures for high pressure control of refrigerant pressure during cooling overload.

(Prior Art) As an example of an air conditioner that has been developed in recent years, there is a heat storage type air conditioner that has a heat storage tank storing a heat storage medium. And its basic structure is
As shown in Publication No. 4661, a heat storage tank having a heat exchanger for heat storage and a heat exchanger for subcooling liquid refrigerant is provided between the air cooling heat exchanger and the condenser, and one side of the heat storage heat exchanger is is connected to the condenser through a refrigerant throttle device and a switching valve, and the other side is connected to the compressor, one side of the liquid refrigerant cooling heat exchanger is connected to the condenser through the switching valve, and the other side is connected to the refrigerant throttle. They are each connected to an air cooling heat exchanger via a device.

In addition, not only the heat storage type air conditioner configured in this way but also an air conditioner having a general refrigerant circuit, if the cooling load increases extremely during cooling operation, the refrigerant pressure in the main refrigerant circuit will be high. Pressure may rise abnormally and damage the equipment.

To prevent this, a high-pressure sensor is generally installed in the refrigerant circuit, and when the discharge pressure of the compressor rises abnormally, this high-pressure sensor works to stop the drive of the device. I have to.

(Problem to be Solved by the Invention) However, in the configuration in which the device is stopped using this high-pressure pressure sensor, there is a loss time between stopping the device and restarting the device. There is a desire to maintain operation at a constant temperature, and a configuration that actively suppresses abnormal increases in refrigerant pressure is desired. Until now, as a means of suppressing this abnormal rise in refrigerant pressure and avoiding equipment stoppage, inverter control that changes the operating frequency of the compressor, unloader control that changes the compression load, etc. have been used to control the compressor capacity. Some are configured to change the refrigerant pressure according to the refrigerant pressure, and by appropriately lowering the capacity, the high pressure of the refrigerant pressure is suppressed from increasing.

However, when adjusting the refrigerant pressure by controlling the capacity of the compressor as described above, there is a limit to the capacity that can be lowered. In other words, if the capacity reduction rate of the compressor is increased, it becomes difficult for the oil released from the compressor into the refrigerant circuit to return to the compressor, or if two or more compressors are installed in parallel (
In the twin compressor), if the capacity reduction rate is increased, the compressor cannot be lubricated evenly with oil, and the above requirements cannot be completely satisfied only by controlling the capacity of the compressor. Furthermore, in order to increase this rate of capacity reduction, it is conceivable to install a large capacity compressor in advance, but this is not preferable as it increases the size of the device and increases the manufacturing cost. Therefore, there is a need for a configuration that uses other means to avoid stopping the device due to the action of the high-pressure pressure sensor.

Therefore, the present invention provides a flow rate control means that can adjust the flow rate of refrigerant flowing between the heat source side heat exchanger and the usage side heat exchanger, and uses this flow rate control means to reduce the amount of refrigerant circulating in the main refrigerant circuit. An object of the present invention is to obtain an air conditioner that can avoid an abnormal increase in refrigerant pressure by doing so.

(Means for Solving the Problems) In order to achieve the above object, the means for solving the problems of the present invention will be described below.

First, the invention described in claim (1), as shown in FIG.
) for the outdoor unit (X) with the main pressure reducing mechanism (6
) and a user-side heat exchanger (7), and a plurality of indoor units (A), (B), ... are connected in parallel through refrigerant piping (9). equipment is assumed. A flow rate adjusting means (52) for adjusting the flow rate of refrigerant flowing between the liquid receiver (5) and the user side heat exchanger (7), and a pressure detecting means (53) for detecting the high pressure of the refrigerant pressure. , a comparison means (54) which receives the output signal of the pressure detection means (53) and compares a preset reference pressure on the high pressure side with the high pressure of the refrigerant pressure; Flow control means (60) is provided for controlling the flow rate adjustment means (52) so as to reduce the amount of refrigerant circulating in the main refrigerant circuit (10) based on the output signal of the comparison means (54).

Further, in the invention according to claim (2), in the air conditioner according to claim (1), as shown in FIG. The main refrigerant circuit (10) is arranged in the tank (11) and
), the basic structure consists of a heat storage heat exchanger (12) for exchanging heat between the refrigerant and the heat storage medium, and a pressure reduction mechanism for cold storage heat (14). During operation, at least during normal cooling operation, the heat source side heat exchanger (3
) The liquid refrigerant condensed in the main refrigerant circuit (10) flows only through the main refrigerant circuit (10), is depressurized by the main pressure reducing mechanism (6), and is transferred to the user-side heat exchanger (7).
During the cold storage heat operation, the liquid refrigerant condensed in the heat source side heat exchanger (3) is depressurized by the cold storage heat decompression mechanism (14), and the stored heat is returned to the compressor (1). Exchanger (
12) and then circulates back to the compressor (1), and during cold storage heat recovery operation, the liquid refrigerant condensed in the heat source side heat exchanger (3) is transferred from the main refrigerant circuit (10) to the storage heat exchanger. (
12), switching means (51) for switching the circuit connection so that the refrigerant is evaporated in the utilization side heat exchanger (7) of the main refrigerant circuit (10) and returned to the compressor (1). It is configured.

In the invention described in claim (3), the above claim (2)
In the air conditioner described above, the flow rate control means (60) includes a flow rate adjustment mechanism (17) as a flow rate adjustment means (52) during the cold storage heat recovery operation, and a cold storage heat decompression mechanism (14) whose opening degree is variable. During normal cooling operation, the flow rate adjustment mechanism (17) is configured to adjust the flow rate of refrigerant flowing through the main refrigerant circuit (10).

Furthermore, in the invention described in claim (4), the above claim (1)
In the air conditioner described in (2) or (3), the compressor (1) is configured to have a variable capacity, while the comparison means (
capacity control means (6) for controlling the compressor (1) so that the capacity of the compressor (1) is reduced in response to the output signal of the compressor (54);
1).

Finally, in the invention described in claim (5), the above-mentioned claim (4)
) In the air conditioner described in ), the capacity control means (61)
is configured to control the compressor capacity to decrease with priority over the flow rate control means (60).

(Function) With the above configuration, in the invention described in claim (1), the pressure detection means (53) detects the high pressure of the refrigerant pressure, and the output signal of the pressure detection means (53) is transmitted to the comparison means (54). sent to. Then, the comparison means (54) compares the preset reference pressure on the high pressure side and the high pressure of the refrigerant pressure, and when the high pressure of the refrigerant pressure exceeds the reference pressure, the comparison means (54)
) is sent to the flow rate control means (60), which controls the flow rate adjustment means (52) to reduce the amount of refrigerant circulation. As the refrigerant circulation amount decreases, the refrigerant pressure within the refrigerant circuit decreases. As a result, a reliable refrigerant pressure reduction effect can be obtained through simple control of the refrigerant circulation amount in accordance with the high pressure of the refrigerant.

Further, in the invention described in claim ('2J), the switching means (51
), the circuit connection is switched, and normal cooling operation, cold storage heat operation, and cold storage heat recovery operation are performed as appropriate. During the normal cooling operation and the cold storage heat recovery cooling operation, the refrigerant circulation amount is reduced, and as the refrigerant circulation amount decreases, the refrigerant circuit is refrigerant pressure is reduced.

In the invention described in claim (3), during the cold storage heat recovery operation,
Flow rate adjustment mechanism (17) and cold storage heat reduction mechanism (, 14),
During normal cooling operation, the refrigerant circulation amount is adjusted by adjusting the opening of the flow rate adjustment mechanism (17) and the refrigerant pressure in the refrigerant circuit is lowered, thereby making it possible to control the refrigerant pressure according to each operating state.

In the invention described in claim (4), in addition to the effects in the invention described in claims (11, !2J or (3) &), the control means (61) controls the inverter when the high pressure of the refrigerant becomes equal to or higher than the reference pressure. The capacity of the compressor is reduced by the control and unloader control.Therefore, the rate of reduction in the amount of refrigerant circulation can be further increased.

In the invention described in claim (5), when the high pressure of the refrigerant pressure reaches a value slightly exceeding the reference pressure, the capacity control means (
61) is activated, and the capacity reduction control of the compressor (1) is given priority over the refrigerant flow rate regulation control by the flow rate control means (60). Then, when the high pressure of the refrigerant pressure exceeds the reference pressure by a predetermined value or more, the flow rate control means (60) performs refrigerant tN and amount regulation control. Thereby, power consumption is reduced without driving the flow rate adjusting means (52) more than necessary.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 3 onwards.

FIG. 3 shows the overall configuration of the air conditioner according to the first embodiment, in which a plurality of indoor units (A), (B), . . . are connected to an outdoor unit (X). It is a type of air conditioner.

In the above outdoor unit (X), (1) is a compressor, (
2) is a four-way switching valve that switches as shown in the solid line in the figure during cooling operation and as shown in the broken line in the figure during heating operation;
) is an outdoor heat exchanger as a heat source side heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation, and (4) is a depressurizer that adjusts the refrigerant flow rate during cooling operation and reduces the pressure of the refrigerant during heating operation. An outdoor electric expansion valve functions as a mechanism, (5) is a receiver for storing condensed liquid refrigerant, and (8) is an accumulator for removing liquid components in the suction refrigerant.

On the other hand, each indoor unit (A), (B), ... has the same configuration, and (6) functions as a pressure reducing mechanism during cooling operation, and serves as the main indoor pressure reducing mechanism to adjust the refrigerant flow rate during heating operation. The electric expansion valve (7) is an indoor heat exchanger as a user-side heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation.

The above-mentioned devices (1) to (8) are sequentially connected through refrigerant piping (9) so that refrigerant can flow therethrough, and have a heat pump effect that releases heat obtained through heat exchange with outdoor air to indoor air. A main refrigerant circuit (10) is configured.

In addition, the device stores cold heat, warm heat by heat exchange with the refrigerant flowing through the main refrigerant circuit (10), or stores cold heat,
A heat storage unit (Y) for utilizing stored heat is arranged. In the heat storage unit (Y), (11) is a heat storage tank storing water (W) which is a heat storage medium capable of storing cold heat and warm heat, and (12) is disposed in the heat storage tank (11), and water (W) is stored in the heat storage tank (12). W) and a refrigerant, the heat storage heat exchanger (12) and the main refrigerant circuit (10
) above outdoor electric expansion valve (4) - indoor electric expansion valve (6)
The first bypass path (13
a) and the second bypass passage (13b), the indoor electric expansion valve (6) is sequentially connected to the indoor electric expansion valve (6) so that the refrigerant can flow therethrough. The first bypass path (13a) is filled with water (W).
) is interposed with a thermal storage electric expansion valve (14) as a cold storage heat depressurization mechanism that depressurizes the refrigerant when storing cold heat in the second bypass path (13b).
) is interposed.

Further, the first on-off valve (1) of the second bypass path (13b)
5) The intermediate piping between the storage heat exchanger (12) and the gas line (9b) of the main refrigerant circuit (10) are connected to the third bypass path (1
3c) is connected to the refrigerant flow l, and this third bypass path (13c) is connected to the third bypass path (1,
A second on-off valve (16) for opening and closing 3C) is provided.

The above-mentioned first line of the liquid line (9a) of the main refrigerant circuit (10). As a feature of the present invention, a main refrigerant circuit (
A flow rate control valve (17) as a flow rate adjusting means for variably adjusting the flow rate of the refrigerant (10) is provided. And each such valve (15).

(1, 6) and (17) constitute a switching means (51) that switches the circuit connection according to each operating state.

In addition, the device is equipped with sensors (T ha
) is an outside temperature sensor arranged at the air suction port of the outdoor heat exchanger (3) and serves as an outside air temperature detection means for detecting the outside air temperature TG, and (Thi) is the second bypass path (13b) of the liquid line (9a). The cooling population sensor (Tho) placed on the upstream side during cooling operation at the junction with the liquid line (9a
), the cooling outlet sensor (T h
s) is a suction pipe sensor placed in the suction line (9d) to detect the suction pipe temperature, and (Sp) is a gas line (9d).
b) is a pressure sensor that detects high pressure Tc during the heating cycle and low pressure (suction pressure) Te during the cooling cycle. The signals detected by these sensors are then sent to the controller (C).

Here, the opening/closing (or opening degree adjustment) of each valve in each operation mode of the device and the refrigerant circulation route are explained in Figures 4 to 4.
This will be explained based on FIG.

During normal cooling operation, as shown by the arrow in Figure 4, the four-way switching valve (2) switches as shown by the solid line in the figure, and the outdoor electric expansion valve (4), the flow rate control valve (17), and the indoor electric expansion valve are switched. (6)
,... are opened and all other valves are closed, and the refrigerant condensed in the outdoor heat exchanger (3) circulates only through the main refrigerant circuit (10), and each indoor electric expansion valve (6),
. . , and is evaporated in each indoor heat exchanger (7), . . . and returned to the compressor (1).

During cold storage heat operation, as shown by the arrows in Figure 5, the outdoor electric expansion valve (4), the flow rate control valve (17), and the heat storage electric expansion valve (
14) and the second rJiJ closing valve (16) are opened, and the operation is performed with the indoor electric expansion valve (6), ... and the first opening/closing valve (15) closed, and the outdoor heat exchanger (3) is operated. The condensed liquid refrigerant bypasses and flows into the first bypass path (13a), is depressurized by the thermal storage electric expansion valve (14), evaporates in the thermal storage heat exchanger (12), and returns to the compressor (1). circulates. At this time, water (W), which is a heat storage medium, is made into ice by exchanging heat with a refrigerant in the heat storage heat exchanger (12), and cold heat is stored.

During normal cooling and cold storage heat simultaneous operation, as shown by the arrows in Figure 6, the outdoor electric expansion valve (4), the flow rate control valve (17),
Indoor electric expansion valve (6), ..., thermal storage electric expansion valve (14)
) and the second)') JJ on-off valve 16) are opened, the first on-off valve (15) is closed, and a part of the liquid refrigerant condensed in the outdoor heat exchanger (3) is transferred to the main refrigerant circuit (10). is depressurized by the indoor electric expansion valve (6), ... and then transferred to the indoor heat exchanger (7),
..., while the remainder of the liquid refrigerant flows to the first bypass path (13a), is depressurized by the heat storage electric expansion valve (14), and evaporates in the heat storage heat exchanger (12). Then, these refrigerants in gaseous state are respectively connected to gas lines (9b).
It joins the air and circulates back to the compressor (1).

During the cold storage heat recovery operation that utilizes the cold heat stored in the cold storage heat operation described above, as shown by the arrow in Figure 7, the outdoor motorized expansion valve (4
), flow control valve (17), indoor electric expansion valve (6),...
・Operation is performed with the heat storage electric expansion valve (14) and the first on-off valve (15) open and the second on-off valve (16) closed, and the refrigerant condensed in the outdoor heat exchanger (3) A part of the refrigerant flows from the main refrigerant circuit (10) to the second bypass path (13b) side, and is supercooled by heat exchange with water (W) (or ice) in the thermal storage heat exchanger (12). 1st bypass path (1
3a) to the main refrigerant circuit (10), while the remaining liquid refrigerant passes through the flow control valve (17) and returns to the main refrigerant circuit (10) as it is.
0) flows through the liquid line (9a). And after merging,
Each indoor electric expansion valve (6).

. . , and is evaporated in each indoor heat exchanger (7), . . . and then circulated back to the compressor (1). At that time, the divided flow rate of the refrigerant is adjusted by adjusting the relative opening of the flow rate control valve (17) and the heat storage electric expansion valve (14), and the cooling population sensor (Thl) and the cooling outlet sensor (T ha)
The degree of supercooling of the refrigerant as the difference temperature ΔTl between the liquid refrigerant temperature TΩ1°Tρ2 detected at is adjusted appropriately.

Next, in normal heating operation, as shown by the arrow in Figure 8, the four-way switching valve (2) switches to the side of the broken line in the figure, and each indoor electric expansion valve (6), ..., flow control valve (1, 7), the outdoor electric expansion valve (4) is opened, and the operation is performed with all other valves closed, and the discharged gas is transferred to each indoor heat exchanger (7),
..., is depressurized by the outdoor electric expansion valve (4), is evaporated in the outdoor heat exchanger (3), and then circulated back to the compressor (1).

During heating operation, the second on-off valve (16), electric heat storage expansion valve (14), and flow rate control valve (1
7), the outdoor electric expansion valve (4) is opened, and each indoor electric expansion valve (6), . 10) to the third bypass path (1-3C), and after being condensed in the regenerative heat exchanger (12), the first bypass path (1-3C)
a) to the main refrigerant circuit (10), and the outdoor electric expansion valve (
After being depressurized in step 4) and evaporated in an outdoor heat exchanger (3), it is circulated back to the compressor (1). At that time, the heat storage tank (11) is heated by heat exchange with the refrigerant in the thermal storage heat exchanger (12).
The water (W) inside is warmed and warm heat is stored.

During normal heating and heating/heat storage simultaneous operation, each indoor electric expansion valve (6), ... second opening/closing valve (16), thermal storage electric expansion valve (14), flow rate control valve, as shown by the arrows in Fig. 10. (17
), the outdoor electric expansion valve (4) opens, and the first on-off valve (15) opens.
Operation is performed with the refrigerant closed, and part of the discharged gas bypasses and flows from the main refrigerant circuit (10) to the third bypass path (1, 3c) and is condensed in the regenerative heat exchanger (12). On the other hand, the remainder of the discharged gas flows through the main refrigerant circuit (10) and is condensed in each indoor heat exchanger (7) 1. After the two are combined, the pressure is reduced by the outdoor electric expansion valve (4), and after being evaporated in the outdoor heat exchanger (3), the air is circulated back to the compressor (1).

Furthermore, during the heat storage heat recovery defrost operation, as shown by the arrow in FIG. 11, the four-way switching valve (2) switches to the solid line side in the figure, and the outdoor electric expansion valve (4), the flow rate control valve (17), Each indoor electric expansion valve (6), ... thermal storage electric expansion valve (14)
, the operation is performed with the second on-off valve (16) open and the first on-off valve (15) closed, and the discharged gas flows into the outdoor heat exchanger (3).
), and a part of the condensed liquid refrigerant flows into the main refrigerant circuit (
The liquid refrigerant flows from the main refrigerant circuit (10) to the first bypass path (13a), is depressurized by the thermal storage electric expansion valve (14), and evaporates in the thermal storage heat exchanger (12). ) is depressurized by each indoor electric expansion valve (6), and evaporated by each indoor heat exchanger (7),.... and,
The gases are joined together in the gas line (9b) and circulated back to the compressor (1). At that time, the outdoor heat exchanger (3) is defrosted by the discharged gas (hot gas), and
Outdoor heat exchanger (3) using the heat stored in the heat storage tank (1)
This increases the condensing capacity of the defrost system and shortens the defrost operation time.

The above controller (C) has an outside temperature sensor (Tha).
, a pressure detection means (53) that receives temperature signals from a suction pipe sensor (Ths) and a frequency detection means (not shown) and calculates a high pressure. Furthermore, the controller (C) includes a comparison means (54) for comparing a preset reference pressure and a high pressure of the refrigerant pressure, and receives an output signal from the comparison means (54) and operates a flow rate control valve (17), etc. Flow rate control means (60) that regulates the refrigerant flow rate by controlling the opening degree of the
, also receives the output signal of the comparison means (54), and compares the compressor (
A capacity control means (61) is configured to reduce the capacity of 1).

The feature of the present invention relates to the control of the refrigerant circulation amount during the above-mentioned normal cooling operation and cold storage heat recovery operation. Hereinafter, this refrigerant circulation amount control will be explained along the flowchart of FIG. 12.

First, after starting and initializing, step S
1, the main refrigerant circuit (10) is detected by the pressure detection means (53).
Calculate the high pressure HP of the refrigerant flowing inside. This high pressure HP is calculated by detecting the outside air temperature TG using the outside air temperature sensor (T ha) and the saturation temperature Te on the low pressure side of the main refrigerant circuit using the suction pipe sensor (Ths). The output, that is, the operating frequency FT is detected, and the detected value is substituted into the following equation to calculate the high pressure HP of the refrigerant pressure.

HP-c1+c2 Fist Te+c3 eTG+c4 ・
FT...■In this example, the values of each constant are determined as follows.

cl...24.51 C2...0. 325 C3...0.42 C4...0.108X3.59xlO'xFTNext,
Proceeding to step S2, the high pressure HP calculated in step S1 and the preset upper limit HP of the high pressure side reference pressure
, (set to 25 kg/cd in this example) by the comparing means (54). Here, if it is determined that the high pressure HP of the refrigerant pressure is equal to or less than the reference pressure upper limit value HP, the process moves to step S3, and in this step S3, the high pressure HP and the lower limit of the preset high pressure side reference pressure are determined. value H
P2 (set to 23.5 kg/cd in this example) is again compared by the comparison means (54). Here, if it is determined that the high pressure HP is smaller than the lower limit value HP2, the process proceeds to step S4, where the high pressure control value i for stepwise control of the high pressure HP of the refrigerant pressure is decreased by 1, and the process proceeds to step S5. When the high pressure control value i is smaller than 0 in step S5, the high pressure control value i is determined in step S6.
In step Sll, the compressor frequency FT is set to the normal operating state by setting O to O, and further, in step S12, the flow rate control valve (17) is
Set to the fully open state during normal operation.

Then, the processing operations of steps 81 to SI2 are repeated at a predetermined timing.

On the other hand, when an overload occurs during cooling operation and the high pressure HP increases, and it is determined in step S2 that the high pressure HP is equal to or higher than the upper limit HPI, the process proceeds to step S7, and the high pressure control value l is set to 7. Then, proceed to step Sl+. At this time,
First, as shown in Table 1, after the capacity control means (61) lowers the frequency to 90)1z, the process moves to step SI2, and during normal cooling operation, the flow rate control means (60) controls the flow rate control valve (17). The opening degree is narrowed to 70%, the refrigerant circulation amount is reduced, and the high pressure HP is lowered.

Thereafter, the operations from step 81 to step SI2 are repeated, and when the high pressure HP falls below the lower limit value HP2,
In step S4, the high pressure control value i is decreased by one step, and the opening degree of the flow rate control valve (17) is set to 80%, and the opening degree is slightly increased. Thereafter, the above operation is repeated, and if the high pressure HP continues to be lower than the lower limit HP2 as shown in Table 1, the opening degree of the flow rate control valve (17) is increased to 100%, while the flow rate control After the valve (17) is fully opened, the frequency of the compressor (1) is increased to 10011z. Further, if the high pressure HP becomes larger than the lower limit HP2 during the high pressure control, the process moves from step S3 to step S8, and the opening degree of the flow control valve (17) and the compressor (
1) Maintain the operating frequency as it is. Also,
During cold storage heat recovery operation, the flow control valve (
17) and the heat storage electric expansion valve (14) at the same time.

Further, even if it is determined in step Ss that the high pressure control value i is 0 or more, the high pressure control value i is maintained as it is and the process proceeds to step Sl+.

Further, during the cold storage heat recovery operation, the flow rate control valve (17) and the heat storage electric expansion valve (14) are simultaneously controlled as shown in Table 1.

Table 1 In addition, as shown in Table 1, in this example, the control minimum value of the upper limit frequency of the compressor (1) was set to 90tTz. This is because if the operating frequency of the compressor (1) is lower than 90Hz, it becomes difficult for the ura in the refrigerant circuit to return to the compressor (1), and when two compressors are used in parallel, it becomes difficult to achieve uniform oil circulation. This is a configuration to prevent these problems.

Here, the basic principle of high pressure control will be explained.

Further downstream of the receiver (5) located downstream of the outdoor heat exchanger (3), by reducing the flow path area, the amount of refrigerant circulated within the circuit is reduced, thereby attempting to reduce the refrigerant pressure. It is something. In other words, Figure 14 shows the relationship between the opening degree of the indoor electric expansion valve (6) according to the opening degree of the flow control valve (17), the compressor refrigerant circulation amount, and the high pressure and low pressure in the circuit. Yes, as you can see from this figure,
When the opening degree of the flow control valve (17) is made smaller than the fully open state, the opening degree of the indoor electric expansion valve (6) increases, and the compressor refrigerant circulation amount and the circuit change around the maximum opening point. Both the high and low pressure inside will drop. The present invention utilizes this principle to reduce the high pressure of the refrigerant in the circuit.

In addition, as another example of this refrigerant circulation amount control, the 13th
Control may be performed as shown in the figure. Regarding this, steps 81 to S6 and steps S11.
Step S+2 is similar to that described above, and in step S2, the high pressure HP of the refrigerant pressure is set to the upper limit value H of the reference pressure.
If it is determined that it is larger than P, the process proceeds to step SI3, where 1 is added to the high pressure control value l, and the process proceeds to step S14. Then, in step S14, it is determined whether or not the high pressure control value 1 is larger than 7, and the process moves to step S+6 until the high pressure control value becomes larger than 7. A timer is set and the process moves to steps 811 and 512, and the compressor (1 ) and flow control valve (
17), waits for the timer to time up in step S17, returns to step S1, and repeats the above operations.

In other words, during normal cooling operation, the high pressure H
When P exceeds the upper limit HP, the high pressure control value is set to 7 to reduce the refrigerant circulation amount in the previous embodiment, but instead of this, the control value i is increased sequentially, and first, The high pressure control value i is set from O to 1, the capacity of the compressor (1) is reduced as shown in Table 1, and if the high pressure does not decrease with this control, the high pressure control value l is set to 1 at the next processing timing.
step up, and increase the capacity of compressor (1) to 'f+Em
Priority is given to the control of the control valve (17) and the frequency is lowered to 90Hz.
If the high pressure does not drop even if the pressure is lowered, the flow control valve (1
7) Control. Then, when the control value reaches 7, the compressor (
1) is reduced to 901 (z) and the flow rate control valve (17) is reduced to 70%.On the other hand, when the high pressure HP decreases, the capacity of the compressor (1) is increased step by step at each time up in step S16. do.

Therefore, by controlling the refrigerant circulation amount in this way, with a simple structure, it is possible to control the flow rate to a much greater extent than by controlling the capacity of the compressor (1), and the discharge pressure of the compressor (1) can be controlled to a much greater extent than by controlling the capacity of the compressor (1). This prevents the equipment from stopping due to an abnormal rise in temperature.

Note that the control of the refrigerant circulation amount as in the present invention can be applied to heating heat storage operation, general air conditioners that do not have a heat storage tank, and even to cooling-only machines.

Further, in this embodiment, the refrigerant pressure was calculated based on the outside air temperature, the low pressure equivalent saturation temperature, and the compressor output, but a pressure sensor may be provided on the discharge side of the compressor to directly detect the refrigerant pressure. Furthermore, the indoor electric expansion valve on the indoor unit side can also be used as the flow rate adjustment means. Further, instead of the stepwise control as in the above embodiment, the valve opening degree and the compressor operating frequency may be controlled continuously.

(Effects of the Invention) As explained above, according to the invention of claim (1), the refrigerant pressure can be reliably lowered by simple control of the refrigerant circulation amount according to the high pressure of the refrigerant. Insufficient oil return to the compressor and imbalance in oil lubrication in twin compressors can be avoided in controlling the drop in refrigerant pressure by lowering the capacity of the compressor. It is possible to reliably lower the refrigerant pressure with a simple structure and low cost, without having to use the high-pressure switch, and it is possible to reduce the number of times the device drive is stopped due to the function of the high-pressure switch.

In the invention of claim (2), by providing a refrigerant pressure control function in a heat storage type air conditioner, in addition to the effect of the invention described in claim (1), it is possible to improve the temperature during cold storage heat operation with a large load. This avoids equipment stoppages.

In the invention of claim (3), by controlling the refrigerant flow rate by the flow rate adjustment mechanism and the cold storage heat decompression mechanism during the cold storage heat recovery operation, it is possible to obtain an appropriate optimal refrigerant flow rate and avoid stopping the device. .

In the invention of claim (4), in addition to the effects in claims (1) to (3), the amount of refrigerant circulation is also reduced by controlling the capacity of the compressor, thereby increasing the rate of decrease in the amount of refrigerant circulation. That is, it is possible to further increase the rate of decrease in refrigerant pressure.

In the invention of claim (5), when the high pressure value of the refrigerant pressure exceeds the reference high pressure value, the capacity control of the compressor is performed with priority, and when the high pressure value of the refrigerant pressure exceeds the reference high pressure value by a predetermined value or more, By controlling the refrigerant flow rate by the flow rate adjustment means only during the refrigerant flow rate, the flow rate adjustment means is not driven more than necessary, thereby reducing power consumption and reducing the running cost of the apparatus.

[Brief explanation of drawings]

FIGS. 1 and 2 are block diagrams showing the configuration of the present invention. 3 to 13 show one embodiment of the present invention, FIG. 3 is a refrigerant piping system diagram showing the overall configuration of the device, and FIGS. 4 to 7 show each operation mode in cooling operation, Fourth
FIG. 5 is an explanatory diagram showing the circulation of refrigerant in normal cooling operation, FIG. 5 in cold storage heat operation, FIG. 6 in normal cooling and cold storage heat simultaneous operation, and FIG. 7 in cold storage heat recovery operation. Figures 8 to 11 each show each operation mode in heating operation, and Figure 8
Figure 9 shows the normal heating operation, Figure 9 shows the heating heat storage operation, Figure 10 shows the normal heating and cold storage heat simultaneous operation, Figure 11 shows the refrigerant circulation route in the heating heat recovery defrost operation, and Figure 1
Figure 2 is a flowchart showing the control contents of this device.
FIG. 3 is a flowchart showing another control content. FIG. 14 is a diagram for explaining the present invention in detail. 1 Compressor 3 Outdoor heat exchanger (heat source side heat exchanger) 5 Receiver 6 Indoor electric expansion valve (main pressure reducing mechanism) Indoor heat exchanger (user side heat exchanger) Refrigerant piping Main refrigerant circuit Heat storage tank Thermal storage Heat exchanger Heat storage Electric expansion valve (pressure reducer for cold storage heat 1iW) Flow rate control valve (flow rate adjustment mechanism) Switching means Flow rate adjustment means Pressure detection means Comparison means Flow rate control means Capacity control means 1 and Fig. 12 Fig. z Fig. 13

Claims (5)

[Claims] (1) For the outdoor unit (X) that has a compressor (1), a heat source side heat exchanger (3), and a liquid receiver (5), a main pressure reduction mechanism (6) and a user side heat exchanger (7) are installed. In an air conditioner equipped with a main refrigerant circuit (10) in which a plurality of indoor units (A), (B), . . . User side heat exchanger (7)
Flow rate adjustment means (52) for adjusting the flow rate of refrigerant flowing between
) and pressure detection means (5) for detecting the high pressure of the refrigerant pressure.
3), a comparison means (54) which receives the output signal of the pressure detection means (53) and compares a preset reference pressure on the high pressure side with the high pressure of the refrigerant pressure; Flow rate control means (52) for controlling the flow rate adjustment means (52) so as to reduce the amount of refrigerant circulation in the main refrigerant circuit (10) based on the output signal of the comparison means (54) when the pressure exceeds the pressure;
60) An air conditioner comprising: (2) In the air conditioner according to claim (1),
A heat storage tank (11) that stores a heat storage medium for storing cold heat;
10) for exchanging heat between the refrigerant and the heat storage medium, and a pressure reduction mechanism for cold storage heat (14).
), and at least during normal cooling operation, a heat source side heat exchanger (3)
The condensed liquid refrigerant flows only through the main refrigerant circuit (10), is depressurized by the main pressure reducing mechanism (6), is evaporated by the user-side heat exchanger (7), and is circulated back to the compressor (1). During cold storage heat operation, the liquid refrigerant condensed in the heat source side heat exchanger (3) is depressurized by the cold storage heat decompression mechanism (14), and the liquid refrigerant is depressurized in the cold storage heat exchanger (14).
After being evaporated in step 2), it is circulated back to the compressor (1),
During the cold storage heat recovery operation, the liquid refrigerant condensed in the heat source side heat exchanger (3) is transferred from the main refrigerant circuit (10) to the thermal storage heat exchanger (1).
After being supercooled in step 2), the refrigerant is evaporated in the user-side heat exchanger (7) of the main refrigerant circuit (10) and returned to the compressor (1). An air conditioner characterized by: (3) In the air conditioner according to claim (2) above,
The flow rate control means (60) includes a flow rate adjustment mechanism (17) as a flow rate adjustment means (52) during cold storage heat recovery operation and a cold storage heat decompression mechanism (14) whose opening degree is variable, and during normal cooling operation. Main refrigerant circuit (10) with flow rate adjustment mechanism (17)
An air conditioner configured to adjust the flow rate of refrigerant flowing through the air conditioner. (4) In the air conditioner according to claim (19), (2) or (3), the compressor (1) is configured to have a variable capacity, while receiving the output signal of the comparing means (54),
An air conditioner characterized in that a capacity control means (61) is provided for controlling the compressor (1) so that the capacity of the compressor (1) is reduced. (5) In the air conditioner according to claim (4),
An air conditioner characterized in that the capacity control means (61) is configured to lower the compressor capacity with priority over the flow rate control means (60).