JPH04335954A - Capacity control device for heat exchanger - Google Patents

Abstract

PURPOSE:To provide a capacity control device for a heat exchanger capable of stabilizing a refrigeration cycle during capacity control and maintaining constant indoor comfort by controlling the capacity of the heat exchanger based on the type of a refrigerant flow during cooling and heating operation when indoor load of a middle term or the like is small. CONSTITUTION:An air separator 2 is installed between an upper stream side heat exchanger 1a and a down stream side heat exchanger 1b. A pressure reducing device is installed to the gas side and the liquid side of the air separator 2. When it works as a condenser, the outlet of the pressure reducing device installed to the gas side piping of the air separator 2 is connected with the inlet of the down stream side heat exchanger 1b whereas the outlet of the down stream side heat exchanger 1b is connected with the down stream side of the pressure reducing device installed to the other outlet piping of the air separator 2.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to heat exchangers, and more particularly to a heat exchanger capacity control device that can automatically bias the capacity of a heat exchanger according to the indoor load, and The present invention relates to an operating method when a capacity control device is applied to a refrigeration cycle.

0002

2. Description of the Related Art Generally, the capacity of an air conditioner is controlled by changing the driving frequency of the compressor or controlling the amount of air blown out from the unit. When the load on the air conditioning field is small during heating operation, the method of controlling the capacity by lowering the drive frequency of the compressor is that the condensing temperature decreases due to the decrease in discharge pressure, which lowers the air blowing temperature from the unit and lowers the indoor temperature. Temperature distribution worsens. In addition, the method of controlling the amount of air blown out from the unit is that liquid refrigerant is stored in the heat exchanger and the discharge pressure increases, and although there is a feeling of heating near the outlet of the unit, the wind speed is decreasing, so the warm air rises. There is a problem in that warm air does not reach the floor, worsening the temperature distribution in the room. A similar problem also occurs during cooling operation.

[0003] As a method of heating and cooling operation during the intermediate period when the load on the air conditioning plant is small, Japanese Patent Application Laid-Open No. 59-1802
As shown in Publication No. 53, in a multi-room air conditioner, a plurality of liquid side branch pipes are provided in the liquid side main pipe of the outdoor unit, and the first gas side main pipe has a low pressure during cooling and a high pressure during heating. A plurality of gas-side first branch pipes are provided, and a plurality of gas-side second branch pipes are provided in the gas-side second main pipe, which has low pressure during heating and high pressure during cooling, and each indoor unit is equipped with an indoor heat exchanger and an auxiliary heat exchanger. Each heat exchanger in each indoor unit is connected in parallel to the liquid side branch pipe, while the indoor heat exchanger is connected to the first gas side branch pipe, and the auxiliary heat exchanger is connected to the gas side second branch pipe. Each heat exchanger is connected to an on-off valve that can block the flow of refrigerant, and during intermediate cooling and heating operations, the on-off valve is operated to allow refrigerant to flow only to the auxiliary heat exchanger. It has been proposed that

[0004] Furthermore, as a method of controlling the capacity of a heat exchanger for capacity control, as shown in Japanese Unexamined Patent Publication No. 2-254263, a condenser disposed inside an outdoor unit casing is divided into two condenser elements. One capacitor element is placed as an upper capacitor in the part of the ventilation path with high air volume, and the other capacitor element is placed as a lower capacitor in the part of the ventilation path with low air volume. are arranged in series, a refrigerant bypass circuit is provided to bypass the upper condenser, a two-way valve is provided as a bypass valve in the middle of the refrigerant bypass circuit, and when the condensing pressure decreases, the bypass valve provided in the bypass circuit is installed. A method has been proposed in which the refrigerant is opened to actively flow refrigerant to the lower condenser to maintain condensation pressure and prevent a decrease in refrigerating capacity.

[0005]

[Problem to be Solved by the Invention] However, this method of controlling the capacity of a heat exchanger detects the temperature or pressure of the heat exchanger using a temperature sensor or a pressure sensor, and sets the temperature or pressure in a microcomputer or the like in advance. There are the following problems in opening and closing the solenoid valve when it is determined that capacity control of the heat exchanger is necessary.

That is, since a solenoid valve is used as a means to control the capacity of the heat exchanger, when the solenoid valve opens and closes, the flow of refrigerant is suddenly blocked, causing a sudden change in the refrigeration cycle and making it unstable. Since the compressor drive frequency and expansion valve are rapidly controlled in an attempt to bring the temperature closer to the set value, the refrigeration cycle becomes unstable and the temperature distribution within the room deteriorates.

An object of the present invention is to automatically control the heat exchanger capacity to the optimum capacity depending on the refrigerant flow pattern during cooling and heating operations such as intermediate periods, and to stabilize the refrigeration cycle during capacity control. An object of the present invention is to provide a capacity control device for a heat exchanger that can always maintain indoor comfort.

[0008]

[Means for Solving the Problems] The present invention provides a refrigeration cycle in which at least a compressor, a condensing heat exchanger, a pressure reducing device, and an evaporating heat exchanger are connected, and the condensing or evaporating heat exchanger is divided. In the heat exchanger capacity control device, the divided heat exchangers are arranged in series with respect to the cooling medium, and a gas-liquid separator is provided between the divided upstream heat exchanger and the downstream heat exchanger. A pressure reducing device is provided on the gas side and liquid side outlet piping of the gas-liquid separator, and when acting as a condenser, the outlet of the pressure reducing device provided on the gas side outlet piping of the gas-liquid separator is connected to the downstream heat exchanger. The gas refrigerant is actively flowed to the downstream heat exchanger by connecting it to the inlet of the gas-liquid separator to actively flow the gas refrigerant to the downstream heat exchanger. The liquid refrigerant is actively flowed to the downstream heat exchanger by connecting to the inlet of the downstream heat exchanger, and the outlet of the downstream heat exchanger is connected to the downstream side of a pressure reducing device provided on the other outlet piping of the gas-liquid separator. It is characterized by

[0009]

[Function] In general, air conditioning during the intermediate period is operated by lowering the drive frequency of the compressor and reducing the amount of refrigerant flowing in the refrigeration cycle, since the load on the air conditioning field is small and the capacity of the heat exchanger is controlled. Since the capacity of the exchanger has not changed,
The pressure of the heat exchanger changes and the temperature blown into the room changes, worsening the temperature distribution in the room. In order to maintain the comfort level of an air-conditioned facility, it is necessary to keep the outlet temperature constant at all times, and to do so, the capacity of the heat exchanger must be made variable in accordance with the amount of refrigerant flowing within the refrigeration cycle.

[0010] When the load on the air conditioning plant is small, the heat exchanger capacity control device configured as described above completely liquefies the refrigerant only in the upstream heat exchanger, so that the air There is no gas in the refrigerant flowing into the liquid separator, and by throttling the pressure reducing device installed at the gas side outlet of the gas-liquid separator, the refrigerant does not flow to the downstream heat exchanger, and the downstream heat exchanger Since the saturation temperature of the refrigerant becomes lower than the temperature of the air conditioning field, the liquid refrigerant is no longer stored in the downstream heat exchanger, so the capacity of the heat exchanger can be reduced. Similarly, when acting as an evaporator, the refrigerant is completely evaporated and gasified only in the upstream heat exchanger, so there is no liquid in the refrigerant flowing into the gas-liquid separator, and the downstream heat exchanger Since no refrigerant flows, the capacity of the heat exchanger can be reduced.

[0011] For this reason, since the capacity of the heat exchanger is controlled using the flow pattern of the refrigerant, there is no sudden change in the refrigeration cycle, and the temperature blown out from the unit is always constant even when the load on the air conditioning field is small. Since it can be maintained at a constant temperature, it is possible to maintain a uniform temperature distribution in the room.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat exchanger capacity control device of the present invention will be specifically explained below based on the embodiments shown in the drawings.

FIG. 1 shows a configuration in which a heat exchanger capacity control device according to an embodiment of the present invention is operated as a condenser, and FIG. 2 is a configuration in which a heat exchanger capacity control device according to an embodiment of the present invention is operated as an evaporator. The configuration for each case is shown below.

In the figure, 1 is a heat exchanger functioning as a condenser, and this condensing heat exchanger 1 is divided into at least an upstream condensing heat exchanger 1a and a downstream condensing heat exchanger 1b.
The upstream condensing heat exchanger 1a is connected to the inlet side of the gas inflow pipe 4 for allowing refrigerant gas to flow in, and the gas-liquid separator 2 for separating refrigerant gas and refrigerant liquid to the outlet side. do. The gas-side outlet pipe 6 and the liquid-side outlet pipe 7 of the gas-liquid separator 2 are provided with flow rate regulating valves 3a and 3b as pressure reducing devices for adjusting the amount of refrigerant flowing out. The outlet of the flow rate regulating valve 3b provided in the liquid-side outlet pipe 7 of the gas-liquid separator 2 is connected to the liquid outflow pipe 5. Further, the outlet of the flow rate regulating valve 3a provided in the gas side outlet pipe 6 of the gas-liquid separator 2 is connected to the inlet side of the divided downstream condensing heat exchanger 1b, and the downstream condensing heat exchanger 1
The outlet b is a flow rate adjustment valve 3a provided in the gas side outlet pipe 6.
The refrigerant liquid is connected to flow into the liquid outflow pipe 5 which flows out on the downstream side of the refrigerant. In this way, a capacity control device for a heat exchanger acting as a condenser is constructed.

Further, 8 is a heat exchanger that functions as an evaporator, and the evaporation heat exchanger 8 is divided into at least an upstream evaporation heat exchanger 8a and a downstream evaporation heat exchanger 8b. A refrigerant pipe 9 is connected to the inlet side of the heat exchanger 8a for flowing a refrigerant in a gas-liquid two-phase state in which refrigerant liquid and refrigerant gas are mixed, and a refrigerant pipe 9 is connected to the outlet side for separating refrigerant gas and refrigerant liquid. Connect the gas-liquid separator 2. The gas-side outlet pipe 6 and the liquid-side outlet pipe 7 of the gas-liquid separator 2 are provided with flow rate regulating valves 3a and 3b as pressure reducing devices for adjusting the amount of refrigerant flowing out. Flow rate adjustment valve 3 provided in the gas side outlet pipe 6 of the gas-liquid separator 2
The outlet of a is connected to the gas outflow pipe 10. Further, the outlet of the flow rate adjustment valve 3b provided in the liquid-side outlet pipe 7 of the gas-liquid separator 2 is connected to the inlet side of the divided downstream evaporative heat exchanger 8b, and The outlet is connected so as to flow into a gas outflow pipe 10 through which the refrigerant gas flows out downstream of the flow rate adjustment valve 3a provided in the gas side outlet pipe 6. In this way, a capacity control device for a heat exchanger acting as an evaporator is constructed.

Next, the principle of operation of the heat exchanger capacity control device will be explained. When a heat exchanger capacity control device is used as a condenser, it is configured as shown in FIG. 1, and there are the following two operation patterns.

(1) Normal operation This pattern occurs when the load on the space in which the heat exchanger acting as a condenser is installed is large, and the gas refrigerant passing through the gas inlet pipe 4 is transferred to the upstream condensing heat exchanger. It flows into the vessel 1a, exchanges heat with the outside air, and condenses. Since the capacity of the upstream condensing heat exchanger 1a is small compared to the normal indoor load, it is not completely condensed at the outlet of the upstream condensing heat exchanger 1a, and flows out as a gas-liquid two-phase state. It flows into the separator 2. The refrigerant flowing into the gas-liquid separator 2 is separated into liquid and gas, the liquid refrigerant descending within the gas-liquid separator 2, and the gas refrigerant rising within the gas-liquid separator 2. Since the separated liquid refrigerant has completed condensation, it is transferred from the liquid side outlet pipe 7 to the flow rate adjustment valve 3b.
The liquid is opened by a certain amount to adjust the outflow amount and lead to the liquid outflow pipe 5. In addition, since the separated gas refrigerant has not completely condensed, the flow rate adjustment valve 3a is opened by a certain amount from the gas side outlet pipe 6 to flow into the downstream condensing heat exchanger 1b, where it exchanges heat with the outside air and is condensed. Completed, the liquid is led to the liquid outflow pipe 5.

When the indoor load is large as described above, the flow rate adjustment valves 3a and 3b are opened to allow the refrigerant to flow through the upstream condensing heat exchanger 1a and the downstream condensing heat exchanger 1b, so that the amount of refrigerant is adjusted to suit the indoor load. Let it be the capacity of the heat exchanger.

(2) Capacity control operation This pattern is used when the load on the space in which the heat exchanger acting as a condenser is installed is small, and the gas refrigerant passing through the gas inlet pipe 4 is heated for condensation on the upstream side. It flows into the exchanger 1a, exchanges heat with the outside air, and condenses. The capacity of the upstream condensing heat exchanger 1a matches the case where the indoor load is small, so that it is completely condensed at the outlet of the upstream condensing heat exchanger 1a,
It flows out as a liquid refrigerant and flows into the gas-liquid separator 2. The liquid refrigerant that has flowed into the gas-liquid separator 2 descends within the gas-liquid separator 2 and is guided from the liquid side outlet pipe 7 to the liquid outflow pipe 5 after opening the flow rate regulating valve 3b by a certain amount to adjust the outflow amount. Here, by restricting the flow rate regulating valve 3a provided at the gas side outlet of the gas-liquid separator 2 so that the saturation temperature of the downstream condensing heat exchanger 1b is equal to or lower than the indoor temperature, the downstream condensing heat exchanger 1b is Liquid refrigerant is not stored in the gas-liquid separator 2 to prevent the refrigerant from flowing into the downstream condensing heat exchanger 1b, and the heat exchanger functions as a condenser. capacity is reduced to match the indoor load.

As described above, when the heat load in the space where the heat exchanger is installed is large, the upstream condensing heat exchanger 1a
and the downstream condensing heat exchanger 1b,
When the heat load is small, the refrigerant flows only through the upstream condensing heat exchanger 1a, so the heat exchanger can be operated with a capacity that matches the heat load, and the refrigeration cycle can be stably maintained at a certain value. Therefore, variations in room temperature can be reduced.

Next, when the heat exchanger capacity control device is used as an evaporator, it has a configuration as shown in FIG. 2, and there are the following two operation patterns.

(1) Normal operation This pattern occurs when the load on the space in which the heat exchanger acting as an evaporator is installed is large, and the refrigerant pipe 9
The gas-liquid two-phase refrigerant passing through the upstream evaporation heat exchanger 8
It flows into the air, exchanges heat with the outside air, and evaporates. Since the capacity of the upstream evaporative heat exchanger 8a is small compared to the normal indoor load, complete evaporation does not occur at the outlet of the upstream evaporative heat exchanger 8a, and gas flows out as a gas-liquid two-phase state. It flows into the liquid separator 2. The refrigerant flowing into the gas-liquid separator 2 is separated into liquid and gas, the liquid refrigerant descending within the gas-liquid separator 2, and the gas refrigerant rising within the gas-liquid separator 2. The separated gas refrigerant is
Since evaporation has been completed, the flow rate adjustment valve 3a is opened by a certain amount from the gas side outlet pipe 6 to adjust the outflow amount and guide the gas to the gas outflow pipe 10. Further, since the separated liquid refrigerant has not completed evaporation, the flow rate adjustment valve 3b is opened by a certain amount from the liquid side outlet pipe 7 to flow into the downstream side evaporation heat exchanger 8b.
Evaporation is completed by exchanging heat with outside air, and the gas is led to the gas outflow pipe 10.

When the indoor load is large as described above, the flow rate adjustment valves 3a and 3b are opened to allow the refrigerant to flow through the upstream evaporative heat exchanger 8a and the downstream evaporative heat exchanger 8b, and the flow rate is adjusted to match the indoor load. Let it be the capacity of the heat exchanger.

(2) Capacity control operation This pattern is used when the load on the space in which the heat exchanger acting as an evaporator is installed is small, and the refrigerant pipe 9
The gas-liquid two-phase refrigerant passing through the upstream evaporation heat exchanger 8
It flows into the air, exchanges heat with the outside air, and evaporates. Since the capacity of the upstream evaporative heat exchanger 8a matches the case where the indoor load is small, it is completely evaporated at the outlet of the upstream evaporative heat exchanger 8a and flows out as a gas refrigerant to the gas-liquid separator 2. flow inside. The refrigerant that has flowed into the gas-liquid separator 2 rises within the gas-liquid separator 2 and is guided from the gas side outlet pipe 6 to the gas outflow pipe 10 after opening the flow rate regulating valve 3a by a certain amount to adjust the outflow amount. Here, the flow rate adjustment valve 3b provided at the liquid side outlet of the gas-liquid separator 2
By throttling the refrigerant, the flow of refrigerant into the downstream evaporative heat exchanger 8b is prevented, and the capacity of the heat exchanger functioning as an evaporator is reduced to a size suitable for the indoor load.

As described above, when the heat exchanger capacity control device is operated as an evaporator, it has the same effect as when it is operated as a condenser.

The determining means for controlling the capacity of the heat exchanger uses a pressure sensor and a temperature sensor to judge the discharge pressure and the temperature of the heat exchanger whose capacity is to be controlled to be a value set in advance by a microcomputer or the like. The flow regulating valves 3a and 3b are adjusted when it is determined that capacity control is necessary.

Next, another embodiment will be described as a determination means for controlling the capacity of a heat exchanger.

FIG. 3 shows a configuration diagram of a determination device of a heat exchanger capacity control device that uses the amount of refrigerant stored in the gas-liquid separator 2 as determination means for controlling the capacity of the heat exchanger. In the figure, 11 is a liquid level sensor that detects the amount of liquid refrigerant stored in the gas-liquid separator 2, and in this embodiment, a capacitance meter is used. Reference numeral 12 denotes a determination device that determines the capacity control of the heat exchanger based on a signal from the liquid level sensor 11, and 13 represents a drive device for a pressure reducing device that operates in response to a control signal from the determination device 12. , drive device 13 are connected by a control signal line 14.

Next, the operation of the judgment device will be explained.

When the heat exchanger capacity control device acts as a condenser, when the load of the air conditioning plant is large, the refrigerant flows through both the upstream condensing heat exchanger 1a and the downstream condensing heat exchanger 1b. Therefore, the liquid level in the gas-liquid separator 2 is at a low level. In addition, when the load on the air conditioning plant is small, the refrigerant is completely condensed only in the upstream condensing heat exchanger 1a, and the liquid refrigerant that was present in the downstream condensing heat exchanger 1b is stored in the gas-liquid separator 2. The liquid level in the gas-liquid separator 2 rises. Therefore, the height of the liquid level in the gas-liquid separator 2 is detected by the liquid level sensor 11, the signal from the liquid level sensor 11 is input to the judgment device 12, and compared with a preset value, the heat exchanger If it is determined that capacity control of
A control signal is output to 3. In addition, if it is determined that capacity control of the heat exchanger is not necessary, a control signal is output to the drive device to open the pressure reducing device 3a, and the downstream condensing heat exchanger 1b is
Allow the refrigerant to flow.

Furthermore, when the capacity control device of the heat exchanger acts as an evaporator, when the load of the air conditioning field is large, the upstream evaporation heat exchanger 8a alone cannot evaporate completely, so that the inside of the gas-liquid separator 2 A liquid refrigerant is stored in the gas-liquid separator 2, and the liquid level in the gas-liquid separator 2 is at a high position. Furthermore, when the load on the air conditioning field is small, the liquid level in the gas-liquid separator 2 is almost non-existent because the liquid is completely evaporated only in the upstream evaporation heat exchanger 8a. Therefore, the height of the liquid level in the gas-liquid separator 2 is measured by the liquid level sensor 11.
The signal from the liquid level sensor 11 is input to the judgment device 12, and compared with a preset value. If it is determined that capacity control of the heat exchanger is necessary, A control signal is output to the drive device 13 so that the pressure reducing device 3b provided at the side outlet 7 is reduced to a certain fixed amount. Further, if it is determined that capacity control of the heat exchanger is not necessary, a control signal is output to the drive device to open the pressure reducing device 3b, and the refrigerant is made to flow to the downstream condensing heat exchanger 8b.

The method of controlling the capacity of the heat exchanger using this judgment means detects the amount of liquid refrigerant in the gas-liquid separator, which changes depending on the required capacity of the heat exchanger, so it uses a temperature sensor or The capacity of the heat exchanger can be controlled more accurately than the method of controlling using a pressure sensor.

Next, as another embodiment of the present invention, an automatic capacity control device for a heat exchanger that can automatically control the capacity of a heat exchanger using only the flow pattern of the refrigerant will be described.

FIG. 4 is a block diagram of a case where an automatic capacity control device for a heat exchanger that can automatically control the capacity of a heat exchanger is used as a condenser, and FIG. 5 is a diagram showing the automatic capacity control device for a heat exchanger. The block diagram shows a case where the evaporator is operated as an evaporator.

In the figure, the gas-liquid separator 2 provided in the embodiment
A gas-liquid separator as shown in FIG. 6 is provided in place of the flow rate regulating valve 3a disposed in the gas side outlet pipe 6.

FIG. 6 shows an embodiment of a sectional view of a gas-liquid separator included in an automatic capacity control device for a heat exchanger. In the figure, 2a is a gas-liquid separator included in the automatic capacity control device of the heat exchanger, and inside the gas-liquid separator 2a is a gas-liquid separator for guiding the refrigerant flowing out from the upstream heat exchanger into the gas-liquid separator 2a. A lower shielding plate 19 is provided above the inlet pipe 16 and an upper shielding plate 18 is provided above the lower shielding plate 19, and a plurality of holes are provided in the upper shielding plate 18 and the lower shielding plate 19 so that the gas refrigerant can flow therethrough. establish. Additionally, a stopper 16 that suppresses the height of the needle 17 that can block the passage of the gas side outlet pipe 6 and a float 15 that can float in the liquid refrigerant are also provided.
The pair is an upper shielding plate 18 and a lower shielding plate 19.
A stopper 16 is disposed between the two.

Next, the operating principle of the automatic capacity control device for a heat exchanger will be explained. The flow state of the refrigerant is the same as in this embodiment, and the operation of the gas-liquid separator 2a will be described here.

(1) When acting as a condenser During normal operation, the refrigerant flowing out from the upstream condensing heat exchanger 1a is in a gas-liquid two-phase state, so the refrigerant stored in the gas-liquid separator 2a The amount decreases and the needle 17 blocks the gas side outlet pipe 6.
The gas refrigerant separated by the gas-liquid separator 2a flows into the downstream condensing heat exchanger 1b through the gas-side outlet pipe 6, evaporates, and is led to the liquid outflow pipe 5, and is then separated by the gas-liquid separator 2a. The liquid refrigerant separated inside passes through the liquid side outlet pipe 7 to the liquid outflow pipe 5.
guided by.

On the other hand, during capacity control operation, since the indoor load and the capacity of the upstream condensing heat exchanger 1a match,
The refrigerant flowing out from the upstream condensing heat exchanger 1a is only liquid refrigerant. Therefore, the amount of refrigerant stored in the gas-liquid separator 2a increases, and the float 1 disposed in the gas-liquid separator 2a increases.
5 is pushed upward, and the needle 17 forming a pair with the float 15 is also pushed upward, thereby blocking the gas side outlet pipe 6. This prevents the refrigerant from flowing into the downstream condensing heat exchanger, and reduces the capacity of the heat exchanger that acts as a condenser to a size suitable for the indoor load.

(2) When acting as an evaporator During normal operation, the refrigerant flowing out from the upstream evaporative heat exchanger 8a is in a gas-liquid two-phase state, so the refrigerant stored in the gas-liquid separator 2a The amount is small and the needle 17 blocks the gas side outlet pipe 6.
is located below, the gas refrigerant separated in the gas-liquid separator 2a is led to the gas outlet pipe 10 through the gas side outlet pipe 6, and the liquid refrigerant separated in the gas-liquid separator 2a is guided to the liquid side outlet. The gas flows through the pipe 7 into the downstream evaporation heat exchanger 8b, evaporates, and is guided to the gas outflow pipe 10.

On the other hand, during capacity control operation, since the indoor load matches the capacity of the upstream evaporation heat exchanger 8a,
The refrigerant flowing out from the upstream evaporative heat exchanger 8a is only gas refrigerant. Therefore, the inside of the gas-liquid separator 2a becomes a gas refrigerant, and the needle 17 that closes the gas side outlet pipe 6 is located at the lowest end. Then, by throttling the flow rate regulating valve 3 provided on the liquid side outlet pipe 7, the flow of refrigerant into the downstream side evaporative heat exchanger is blocked, and the capacity of the heat exchanger acting as an evaporator is adjusted to the indoor load. can be reduced to the same size.

In this embodiment, the capacity of the heat exchanger is controlled mechanically using the flow pattern of the refrigerant without using electronic devices such as sensors or microcomputers. Capacity can be controlled automatically. In addition, the operating speed of the needle 17 disposed in the gas-liquid separator 2a used for capacity control is suppressed by the amount of liquid refrigerant accumulated in the gas-liquid separator, that is, the rate of change of the refrigeration cycle. It can be kept stable at all times, and the temperature distribution in the room can be kept uniform and stable.

Next, a description will be given of an operating method when the heat exchanger capacity control device is incorporated into a refrigeration cycle.

FIG. 7 is a system diagram showing an embodiment of a refrigeration cycle using the heat exchanger capacity control device of the present invention as a condenser and an evaporator.

In the figure, 20 is a compressor, 21 is an expansion valve which is the main pressure reducing device of the refrigeration cycle, and by connecting the heat exchanger capacity control device of the present invention with piping in an annular manner as shown in the figure. A refrigeration cycle is configured.

Next, the operating method for each driving pattern will be explained.

(1) When an operation command signal is input to the refrigeration cycle at startup,
The compressor 20 is operated at a predetermined frequency, and the refrigerant flows as indicated by the solid arrow. At the time of startup, the opening degree of the flow rate regulating valve 3 provided in the capacity control device of the heat exchanger that acts as a condenser is reduced, and liquid refrigerant is stored in the gas-liquid separator 2a on the condenser side. The stored liquid refrigerant raises the float 15 disposed in the gas-liquid separator 2a, pushes the needle 17 paired with the float 15 upward, and closes the gas side outlet pipe 6. As a result, the capacity of the heat exchanger that acts as a condenser is controlled and becomes only the upstream condensing heat exchanger 1a, and as the capacity of the heat exchanger decreases, the discharge pressure increases in a short time, and the capacity as a condenser increases. can be drawn out in a short time, shortening the start-up time.

(2) When the indoor load is large during normal operation, the heat exchangers are used as described above: the upstream condensing heat exchanger 1a, the downstream condensing heat exchanger 1b, and the upstream condensing heat exchanger 1b. The refrigerant flows through the evaporation heat exchanger 8a and the downstream evaporation heat exchanger 8b to exhibit a predetermined capacity. At this time, the refrigerant is separated by a gas-liquid separator provided in the capacity control device of each heat exchanger, and only the refrigerant that has not completed condensation or evaporation is allowed to flow to the downstream heat exchanger. , the amount of refrigerant flowing to each downstream heat exchanger is reduced. This makes it possible to reduce pressure loss in each downstream heat exchanger, thereby improving the efficiency of the refrigeration cycle and saving energy. In addition, the liquid refrigerant leaving the condenser is depressurized by the flow rate adjustment valve 3 attached to the capacity control device of the heat exchanger that acts as a condenser, and the liquid refrigerant is inside the pipe connecting the flow rate adjustment valve and the expansion valve which is the main pressure reduction device. becomes a gas-liquid two-phase state. This reduces the amount of liquid in the connection pipe on the liquid side, making it possible to reduce the total amount of refrigerant sealed in the refrigeration cycle.

[0049]

[Effects of the Invention] According to the present invention, divided heat exchangers are arranged in series with respect to the cooling medium, and a gas-liquid separator is provided between the divided upstream heat exchanger and downstream heat exchanger. A pressure reducing device is installed on the gas side and liquid side outlet piping of the gas-liquid separator, and when acting as a condenser, the outlet of the pressure reducing device installed on the gas side outlet piping of the gas-liquid separator is connected to the inlet of the downstream heat exchanger. When acting as an evaporator, connect the outlet of the pressure reducing device installed in the liquid side outlet piping of the gas-liquid separator to the inlet of the downstream heat exchanger to actively circulate the liquid refrigerant. Since the outlet of the downstream heat exchanger is connected to the downstream side of the pressure reducing device installed on the other outlet piping of the gas-liquid separator, the load in the room where the heat exchanger is installed is The capacity of the heat exchanger changes accordingly, and even if the indoor load changes, the refrigeration cycle can be maintained at a certain constant value, and the indoor temperature distribution can be kept uniform.

Furthermore, when the heat exchanger capacity control device of the present invention is applied to a refrigeration cycle, the amount of refrigerant flowing to the downstream heat exchanger when the load of the air conditioning plant is large is reduced compared to the conventional heat exchanger. Therefore, the pressure loss of the heat exchanger can be reduced, the efficiency of the refrigeration cycle can be improved, and energy savings can be achieved.

Furthermore, by controlling the capacity of the capacity control device of the heat exchanger that acts as a condenser to be reduced at the time of starting the refrigeration cycle, the discharge pressure can be increased in a short time and the start-up time can be shortened. can.

In addition, the pressure of the liquid refrigerant exiting the condenser is reduced by the flow rate regulating valve attached to the capacity control device of the heat exchanger that acts as a condenser, and the refrigerant in a two-phase gas-liquid state is present in the liquid piping of the refrigeration cycle. Since the refrigerant flows, the total amount of refrigerant sealed can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a capacity control device for a heat exchanger functioning as a condenser, which is an embodiment of the present invention.

FIG. 2 is a block diagram of a capacity control device for a heat exchanger functioning as an evaporator, which is an embodiment of the present invention.

FIG. 3 is a block diagram showing an embodiment of the determination device in the heat exchanger capacity control device of the present invention.

FIG. 4 is a block diagram of an automatic capacity control device for a heat exchanger functioning as a condenser, which is another embodiment of the present invention.

FIG. 5 is a block diagram of an automatic capacity control device for a heat exchanger functioning as an evaporator, which is another embodiment of the present invention.

FIG. 6 is a sectional view showing an embodiment of a gas-liquid separator included in the automatic capacity control device for a heat exchanger of the present invention.

FIG. 7 is a system diagram showing an embodiment of a refrigeration cycle using the heat exchanger capacity control device of the present invention as a condenser and an evaporator.

[Explanation of symbols]

1a... Upstream condensing heat exchanger, 1b... Downstream condensing heat exchanger, 2, 2a... Gas-liquid separator, 3, 3a, 3b... Flow rate adjustment valve.

Claims (1)

[Claims] Claim 1: A capacity control device for a heat exchanger in which a condensing or evaporating heat exchanger of a refrigeration cycle including a compressor, a condensing heat exchanger, a pressure reducing device, and an evaporating heat exchanger is divided,
The divided heat exchanger is arranged in series with respect to the cooling medium, a gas-liquid separator is provided between the divided upstream heat exchanger and the downstream heat exchanger, and the gas of the gas-liquid separator is A pressure reducing device is provided in the side and liquid side outlet piping, and when acting as a condenser, the outlet of the pressure reducing device provided in the gas side outlet piping of the gas-liquid separator is connected to the inlet of the downstream heat exchanger, When acting as an evaporator, the outlet of the pressure reducing device provided on the liquid side outlet pipe of the gas-liquid separator is connected to the inlet of the downstream heat exchanger, and the outlet of the downstream heat exchanger is connected to the gas-liquid separator. A capacity control device for a heat exchanger, characterized in that the device is connected to the downstream side of the pressure reducing device provided on the other outlet pipe of the liquid separator.