JPH062986A - Multi-refrigerant cycle apparatus - Google Patents

Abstract

PURPOSE:To always suitably hold superheat degree in a suction part of a compressor and to increase an operating range by providing means for connecting an intermediate-pressure conduit to a low-pressure conduit via a tube through a heat source side expansion valve between one heat source unit and a plurality of using units. CONSTITUTION:A plurality of using units 7 are connected in parallel with one heat source unit 6 through a high-pressure conduit 12, a low-pressure conduit 13 and an intermediate-pressure conduit 14. In this case, at the time of overheat operating, for example, the units 7, a throttling amount of a using side first expansion valve 9 (K) of the unit 7 (K) of a non-maximum thermal load except except the unit 7 (J) of maximum thermal load is regulated, and a condensing amount of a using side heat exchanger 8 (K) is reduced as compared with that of a using side heat exchanger 8 (J). A throttling amount of a heat source side second expansion valve 15 of the unit 6 is regulated, refrigerant of the conduit 14 is sucked in a suitable amount to the conduit 13, thereby suitably holding refrigerant superheat degree in a suction part of a compressor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-refrigerating cycle device for heating or cooling a plurality of terminals used in a heat load system such as air conditioning and hot water supply.

[0002]

2. Description of the Related Art FIG. 3 is a cycle configuration diagram of a conventional multi-refrigeration cycle apparatus, which includes a compressor 1, a heat source side heat exchanger 2, a heat source side first expansion valve 3, a heat source side first on-off valve 4, and a heat source. The second side opening / closing valve 5 is provided in the heat source unit 6 as shown in the figure. On the other hand, a plurality of utilization units 7 (n) (n = 1,
2, ..., N) are the use side heat exchanger 8 (n), the use side first expansion valve 9 (n), the use side first opening / closing valve 10 (n), and the use side second opening / closing valve 11 ( n). Then, the heat source unit 6 and the high-voltage parts of the utilization units 7 (n),
The low pressure part and the intermediate pressure part are respectively a high pressure line 12 and a low pressure line 1.
3 and the intermediate pressure line 14 to form a closed circuit, and the refrigerant is sealed inside the closed circuit.

The operation of the conventional multi-refrigeration cycle apparatus having such a configuration will be described below.

During the heating operation of the utilization unit 7 (n), the heat source side first opening / closing valve 4 is closed, the heat source side second opening / closing valve 5 is opened, and the utilization side first opening / closing valve 10 (n) is opened. Second on-off valve 11
(N) is closed, the refrigerant is compressed in the compressor 1 to become high-temperature and high-pressure vapor, which is discharged to the high-pressure pipeline 12, and the usage-side first on-off valve 10 (n) in each usage unit 7 (n). Through to the utilization side heat exchanger 8 (n). At this time, the utilization side heat exchanger 8 (n) functions as a condenser, and heat is applied to the heat load to condense and liquefy the refrigerant.

The liquefied refrigerant is used by the first expansion valve 9 on the use side.
(N), the intermediate pressure line 14, and the heat source side first expansion valve 3 to reach the heat source side heat exchanger 2. At this time, the heat-source-side heat exchanger 2 functions as an evaporator, receives heat from the heat source and evaporates to become low-pressure vapor, which is sucked into the compressor 1 through the heat-source-side second opening / closing valve 5 and the low-pressure pipe 13. To be done.

During the cooling operation of the utilization unit 7 (n), the heat source side first opening / closing valve 4 is opened, the heat source side second opening / closing valve 5 is closed, and the utilization side first opening / closing valve 10 (n) is closed. Second on-off valve 11
(N) is opened, the heat source side heat exchanger 2 functions as a condenser, and the use side heat exchanger 8 (n) functions as an evaporator, and absorbs heat from the heat load.

[0007]

However, in such a multi refrigeration cycle apparatus, each utilization unit 7 is used.
When the heat loads in (n) are significantly different, it is necessary to adjust the throttle amount in each use-side first expansion valve 9 (n) according to the heat load, but this causes the cycle balance to deviate from the optimum point. I will end up.

That is, when the utilization unit 7 (n) is in the heating operation, the utilization unit 7 having a non-maximum heat load other than the utilization unit 7 (J) having the maximum heat load (J is one of N).
(K) (K is other than J of N) Each use-side first expansion valve 9
Use side heat exchanger 8 (K) by adjusting the throttle amount at (K)
The amount of condensation in the use side heat exchanger 8 (J) is made smaller than that in the use side heat exchanger 8 (J).
The accumulation of the liquid refrigerant in (K) increases and heat source side heat exchanger 2
There is a problem that the amount of refrigerant in the inside becomes insufficient, the degree of refrigerant superheat in the suction portion of the compressor 1 becomes large, and the refrigerant temperature in the discharge portion of the compressor 1 exceeds the allowable operating temperature, making it impossible to operate.

Similarly, when the utilization unit 7 (n) is in the cooling operation, the utilization unit 7 (K) having a non-maximum heat load is also used.
Each use-side first expansion valve 9 (K) (K is other than J in N)
The amount of evaporation in the use side heat exchanger 8 (K) is adjusted to be smaller than the amount of evaporation in the use side heat exchanger 8 (J) by adjusting the throttle amount in the above. There is a problem that the degree of superheat of the refrigerant becomes large and the temperature of the refrigerant in the discharge portion of the compressor 1 exceeds the allowable operating temperature, which makes operation impossible.

The present invention has been made in consideration of the problems of the conventional multi-refrigeration cycle apparatus, and an object thereof is to provide a multi-cooling heat cycle apparatus which does not cause operational troubles even when there is a large difference in heat load capacity. To do.

[0011]

In order to solve the problem that the degree of superheat of the refrigerant in the suction portion of the compressor becomes large, the first method of the present invention is to expand the intermediate pressure line and the low pressure line to the second heat source side expansion. A second method is characterized in that a control valve is provided between each of the first and second opening / closing valves and each of the heat exchangers.

[0012]

In the present invention, in order to solve the problem that the degree of superheat of the refrigerant in the suction portion of the compressor becomes large, in the first method, the throttle amount of the second heat source side expansion valve is adjusted to adjust the throttle of another expansion valve. Regardless of the amount, the refrigerant superheat degree in the suction portion of the compressor is always kept appropriate, and operation is possible even when the heat loads differ greatly.

In the second method, the amount of heat exchanged in each heat exchanger is adjusted to an amount corresponding to each heat load by adjusting the opening of the control valve, and the expansion amount of each expansion valve is adjusted to adjust the compressor. The degree of superheat of the refrigerant in the suction part of is always maintained at an appropriate level, and the operation can be performed even when the heat loads greatly differ.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cycle configuration diagram of a first embodiment of a multi-refrigeration cycle apparatus according to the present invention, which constitutes a refrigeration cycle similar to that of FIG. 3, and further includes a low pressure line 13 and an intermediate pressure line 14. Is connected via a heat source side second expansion valve 15, and the same elements as in FIG. 3 are denoted by the same reference numerals.

The operation of the multi-refrigeration cycle apparatus of this embodiment having the above structure will be described below.

When the utilization unit 7 (n) (n may be any number) is in the heating operation, the utilization unit 7 having the maximum heat load is used.
(J) (J is one of N) In each utilization side first expansion valve 9 (K) of non-maximum heat load utilization unit 7 (K) (K is other than J of N) The amount of condensation is adjusted so that the amount of condensation in the use side heat exchanger 8 (K) is smaller than the amount of condensation in the use side heat exchanger 8 (J), and as a result, the use side heat exchanger 8 (K). The amount of liquid refrigerant accumulated in the heat source side heat exchanger 2 becomes insufficient, and the refrigerant superheat degree in the suction portion of the compressor 1 is likely to become large. However, the heat source side second expansion valve 15 The refrigerant in the intermediate pressure line 14 is sucked into the low pressure line 13 by adjusting the throttle amount, and the superheat degree of the refrigerant in the suction portion of the compressor 1 becomes appropriate.

Similarly, when the utilization unit 7 (n) is in a cooling operation, the utilization unit 7 (K) having a non-maximum heat load is also used.
Each use-side first expansion valve 9 (K) (K is other than J in N)
The amount of evaporation in the use side heat exchanger 8 (K) is made smaller than the amount of evaporation in the use side heat exchanger 8 (J) by adjusting the throttling amount at 1. Although the degree of superheat of the refrigerant is likely to be large, by adjusting the throttle amount of the heat source side second expansion valve 15, the refrigerant in the intermediate pressure line 14 is sucked into the low pressure line 13 in an appropriate amount, and thus in the suction portion of the compressor 1. Refrigerant superheat becomes appropriate.

FIG. 2 is a cycle configuration diagram of a second embodiment of the multi-refrigerating cycle device according to the present invention, which constitutes a refrigerating cycle similar to that of FIG. 3, and further includes a utilization side first on-off valve 10 (n). And the use side first control valve 16 (n) between the use side second on-off valve 11 (n) and the use side heat exchanger 8 (n).
The heat source side first opening / closing valve 4 and the heat source side second opening / closing valve 5 are provided.
The heat source side first control valve 17 is provided between the heat source side heat exchanger 2 and the heat source side heat exchanger 2, and the same elements as those in FIG. 3 are denoted by the same reference numerals.

The operation of the thus constructed multi-refrigeration cycle apparatus of this embodiment will be described below.

When the utilization unit 7 (n) is in a heating operation, the utilization unit 7 (K) (with a non-maximum heat load) other than the utilization unit 7 (J) with the maximum heat load (J is one of N). K
The amount of condensation is utilized by adjusting the amount of throttling in each of the usage-side first control valves 16 (K) of N other than J) to lower the condensation pressure in the usage-side heat exchanger 8 (K). The amount of refrigerant in the usage-side heat exchanger 8 (n) is made appropriate by reducing the amount of condensation in the side-side heat exchanger 8 (J) and adjusting the throttle amount of the usage-side first expansion valve 9 (n). As a result, the amount of refrigerant in the heat source side heat exchanger 2 becomes appropriate, and the degree of refrigerant superheat in the suction portion of the compressor 1 becomes appropriate.

When the total heat load is small and the suction pressure of the compressor 1 exceeds the allowable operating pressure range, the compressor 1 is adjusted by adjusting the throttle amount of the heat source side first control valve 17.
The suction pressure of is within the allowable operating pressure range.

Similarly, when the utilization unit 7 (n) is in the cooling operation, the utilization unit 7 (K) having a non-maximum heat load is also applied.
Each use-side first control valve 16 (K is other than J in N)
Use side heat exchanger 8 (K) by adjusting the throttle amount at (K)
By increasing the evaporation pressure at, the evaporation amount is made smaller than the evaporation amount at the utilization side heat exchanger 8 (J),
In addition, the amount of refrigerant in the usage-side heat exchanger 8 (n) is optimized by adjusting the throttle amount of the usage-side first expansion valve 9 (n), and the refrigerant superheat degree in the suction portion of the compressor 1 becomes appropriate.

Further, when the total heat load is small and the discharge pressure of the compressor 1 falls below the allowable operating pressure range, the discharge pressure of the compressor 1 is adjusted by adjusting the throttle amount of the heat source side first control valve 17. Is within the allowable operating pressure range.

It goes without saying that the present invention can be applied to a heat load system other than the air conditioning and hot water supply system.

[0026]

As described above, in the multi-refrigeration cycle apparatus according to the present invention, the intermediate pressure line and the low pressure line are connected by piping via the second heat source side expansion valve, or each of the first and the first refrigeration cycle. By providing a control valve between the two on-off valves and each heat exchanger, it is possible to always maintain an appropriate degree of superheat in the suction part of the compressor, thereby realizing proper operation when each heat load is significantly different, Further, by providing the heat source side control valve, the suction or discharge pressure of the compressor can always be kept within the allowable operating pressure range, so that operation under a wide range of conditions can be realized.

[Brief description of drawings]

FIG. 1 is a cycle configuration diagram of a first embodiment of a multi-refrigeration cycle device according to the present invention.

FIG. 2 is a cycle configuration diagram of a second embodiment of the multi-refrigeration cycle device according to the present invention.

FIG. 3 is a cycle configuration diagram of a conventional multi-refrigeration cycle device.

[Explanation of symbols]

 1 Compressor 2 Heat source side heat exchanger 3 Heat source side first expansion valve 4 Heat source side first opening / closing valve 5 Heat source side second opening / closing valve 6 Heat source unit 7 (n) Utilization unit 8 (n) Utilization side heat exchanger 9 ( n) Use-side first expansion valve 10 (n) Use-side first opening / closing valve 11 (n) Use-side second opening / closing valve 12 High-pressure line 13 Low-pressure line 14 Intermediate-pressure line 15 Heat-source-side second expansion valve 16 (n) ) User side first control valve 17 Heat source side first control valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Tagashira 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A heat source unit having a compressor, a heat source side heat exchanger, a heat source side first expansion valve, a heat source side second expansion valve, a heat source side first opening / closing valve, and a heat source side second opening / closing valve, A plurality of utilization units having a utilization-side heat exchanger, a utilization-side first expansion valve, a utilization-side first opening / closing valve, a utilization-side second opening / closing valve, and the plurality of utilization units arranged in parallel to the heat source unit. A high pressure pipeline, a low pressure pipeline, and an intermediate pressure pipeline for connection to the compressor, and the discharge pipe of the compressor and the gas side pipe of the heat source side heat exchanger are piped through the heat source side first on-off valve. Connected,
The suction pipe of the compressor and the gas side pipe of the heat source side heat exchanger are connected to each other via the heat source side second on-off valve, and the liquid side pipe of the heat source side heat exchanger and the intermediate pressure line are the heat source. -Side first expansion valve is connected by piping, the compressor discharge piping and the high-pressure pipeline are connected by piping, the compressor suction piping and the low-pressure pipeline are connected by piping, and each of the utilization side heat exchanges The liquid side pipe of the vessel and the intermediate pressure line are connected to each other through the first use side expansion valves, and the gas side pipe and the high pressure line of the respective use side heat exchangers are the respective use side first opening / closing. Pipe connection via a valve, the gas side pipe of each of the use side heat exchangers and the low pressure pipe are connected via a pipe of each of the use side second on-off valves, and further, the heat source side second expansion The low pressure line and the intermediate pressure line are pipe-connected via a valve. Multi-refrigeration cycle apparatus. 2. A heat source unit having a compressor, a heat source side heat exchanger, a heat source side first expansion valve, a heat source side first opening / closing valve, and a heat source side second opening / closing valve; -Side first expansion valve, use-side first control valve, use-side first on-off valve, a plurality of use units having a use-side second on-off valve, and the plurality of use units in parallel to the heat source unit A high-pressure pipe, a low-pressure pipe, and an intermediate-pressure pipe to be connected are provided, and the discharge pipe of the compressor and the gas-side pipe of the heat-source-side heat exchanger are pipe-connected through the heat-source-side first opening / closing valve, The suction pipe of the compressor and the gas side pipe of the heat source side heat exchanger are connected to each other via the heat source side second on-off valve, and the liquid side pipe of the heat source side heat exchanger and the intermediate pressure line are the heat source. Piping is connected via the first expansion valve on the side, and the discharge pipe of the compressor and the high-pressure pipe are connected to each other. The suction pipe of the compressor and the low-pressure pipe are pipe-connected, and the liquid-side pipe of each of the use-side heat exchangers and the intermediate pressure pipe are pipe-connected through the use-side expansion valves, Further, the branch end of the branch gas side pipe connected to the gas side of each of the use side heat exchangers via the use side first control valve and the high-pressure pipeline connect the use side first on-off valves. The multi-refrigerating cycle device is characterized in that the other end of the branch gas side pipe and the low-pressure pipe are pipe-connected via the respective use-side second on-off valves. 3. A branch pipe of a branch gas side pipe connected to a gas side of a heat source side heat exchanger via a heat source side first control valve and a discharge pipe of the compressor form the heat source side first on-off valve. The multi-refrigerating machine according to claim 2, wherein the suction pipe of the compressor and the other end of the branch gas side pipe are pipe-connected via the heat source side second on-off valve. Cycle equipment.