JP2002048359A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner to prevent freezing of fluid utilized during cooling operation even when a non-azeotropic mixture refrigerant is used and heat exchange efficiency is high both during cooling operation and heating operation. SOLUTION: The air conditioner comprises a refrigerating cycle where a compressor 1, a heat exchanger 2 on the heat exhaust side, a plurality of heat exchangers 3 and 4 on the utilization side, and a pressure reducing device 5 are interconnected through piping, and a utilization fluid circuit where a plurality of heat exchangers on the utilization side is interconnected in series. One of a flow of a refrigerant of a refrigerating cycle and a flow of utilizing fluid for the utilizing fluid circuit forms a parallel flow and the other forms an opposite flow in the heat exchangers 3 and 4 on the utilization side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for cooling and heating, and is particularly suitable for an air conditioner having a plurality of use side heat exchangers and a use fluid circuit for connecting each of them.

[0002]

2. Description of the Related Art Conventionally, a refrigerating apparatus is provided with a switching device for switching a plurality of use-side heat exchangers, that is, a fluid used in a cooler, that is, a brine circuit, and a refrigerant circuit in series and in parallel. Switching is known to reduce the power of the brine pump and more preferably adjust the temperature of the refrigeration load.
No. 0-267494.

[0003]

In the above prior art, a plurality of use side heat exchangers, that is, coolers, are all used as counter flow type heat exchangers, and there is not enough consideration regarding freezing of the use fluid. In particular, no consideration is given to using a non-azeotropic mixed refrigerant, and the heat exchange efficiency may be reduced.

[0004] It is an object of the present invention to solve the above-mentioned problems in the prior art and to provide an air conditioner that prevents freezing of a used fluid during cooling operation and has high heat exchange efficiency in both cooling operation and heating operation. .

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a refrigeration cycle in which a compressor, an exhaust heat-side heat exchanger, a plurality of use-side heat exchangers and a pressure reducing device are connected by piping. In the air conditioner provided with a use fluid circuit for connecting the use side heat exchanger and the air conditioning load, the plurality of use side heat exchangers connected in parallel as the refrigeration cycle, and the plurality of use side heat exchangers And a flow of the refrigerant of the refrigeration cycle and a flow of the use fluid of the use fluid circuit, wherein one of the plurality of use-side heat exchangers is a parallel flow and the other is a parallel flow. This is a counter flow.

[0006] In the above, it is desirable that the plurality of utilization side heat exchangers are laminated plate type heat exchangers.

[0007] Further, in the above, it is desirable that the upstream side of the utilization fluid be a parallel flow and the downstream side be a counterflow.

Further, in the above-described apparatus, the upstream side of the use fluid is set as a parallel flow and the downstream side is used as a counter flow during the cooling operation, and the downstream side of the use fluid is used as the counter flow and the upstream side is used as the counter flow during the heating operation. Is desirable.

Further, the present invention relates to a plurality of refrigeration cycles in which a compressor, a heat-exchanger-side heat exchanger, a use-side heat exchanger, and a pressure reducing device are connected by piping, and a use-side heat exchanger in the plurality of refrigeration cycles. In an air conditioner provided with a use fluid circuit for connecting an air conditioning load, the use-side heat exchanger is a laminated plate heat exchanger, and the flow of refrigerant in the refrigeration cycle and the flow of use fluid in the use fluid circuit are different. In the utilization-side heat exchanger of each of the refrigeration cycles, one is in a parallel flow and the other is in a counterflow.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a cycle configuration of a single cycle machine of a heat pump type air conditioner according to an embodiment, wherein 1 is a compressor, 6 is a four-way switching valve, 2 is a heat-exchange-side heat exchanger, 5 is an expansion valve, The use side heat exchangers 3 and 4 are connected in parallel. Here, the solid line and the dotted line of the four-way switching valve 6 indicate the state during the cooling operation and the state during the heating operation, respectively. Further, solid arrows and dotted arrows in FIG. 1 indicate the flow directions of the refrigerant during cooling and during heating, respectively.

In the cooling operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 passes through the solid line path of the four-way switching valve 6 and is condensed by the exhaust-side heat exchanger 2 to become a high-temperature and high-pressure liquid refrigerant, and expands. The pressure is reduced by the valve 5, evaporated by the use side heat exchangers 3 and 4 formed by the laminated plate type heat exchanger, turned into a low-temperature low-pressure gas refrigerant, and returned to the compressor 1.

In the case of the heating operation, the four-way switching valve 6 is switched to the position shown by the dotted line, and the high-temperature and high-pressure gas refrigerant compressed by the compressor 1 passes through the dotted-line path of the four-way switching valve 6 to use the heat exchanger on the use side. Flow into 3 and 4. At this time, the refrigerant becomes high-temperature and high-pressure liquid refrigerant by the use-side heat exchangers 3 and 4, is decompressed by the expansion valve 5, flows into the exhaust heat-side heat exchanger 2, is heat-exchanged, becomes low-temperature and low-pressure gas refrigerant, and becomes a compressor. Return to 1.

FIG. 13 is a front view of the use side heat exchangers 3 and 4, FIG. 14 is an assembly configuration diagram, FIG. 15 is an internal detailed view, and FIG.
FIG. 16 is a schematic cross-sectional plan view showing the inside of the use-side heat exchanger, and solid arrows and dotted arrows in FIG. 16 indicate flow directions of a use fluid and a refrigerant when used as a counter-flow heat exchanger in the cooling operation, respectively. Show. These use side heat exchangers 3, 4 are located between the front cover plate 10a and the rear cover plate 10d.
A predetermined number of brazing members 10c and a plurality of thin channel plates 10b formed by punching and formed by helibone are alternately stacked. Further, in a vacuum heating furnace (not shown), the laminated edge forming projections P are integrally formed by line contact by vapor deposition brazing, and a flow path 15 bent in the vertical direction is formed. Flow alternately and perform heat exchange via the channel plate 10b. The bent flow path 15 formed between the channel plates 10b is very narrow, and when the flow velocity of the working fluid flowing through the flow path 15 decreases during the cooling operation, the temperature of the working fluid approaches the temperature of the refrigerant, Is low, the used fluid starts to freeze, the expanded used fluid pushes and expands the channel plate 10b, and the use-side heat exchangers 3 and 4 are destroyed.

Reference numeral 12 denotes a use fluid flow path of the use side heat exchangers 3, 4, which is composed of an upper nozzle 12a and a lower nozzle 12b, while reference numeral 14 denotes a refrigerant flow path of the use side heat exchangers 3, 4. It comprises an upper nozzle 14a and a lower nozzle 14b.
The used fluid flow path 12 and the refrigerant flow path 14 flow in the vertical direction of the laminated plate heat exchanger, and the refrigerant flows in from the lower nozzle 14b during the cooling operation and flows into the upper nozzle 14a.
From the upper nozzle 14a during the heating operation and out of the lower nozzle 14b. Therefore, when the used fluid flows in from the upper nozzle 12a and flows out from the lower nozzle 12b, it becomes a counter-flow heat exchanger during the cooling operation, and becomes a parallel-flow heat exchanger during the heating operation. Conversely, when the used fluid flows in from the lower nozzle 12b and flows out from the upper nozzle 12a, it becomes a parallel flow heat exchanger during the cooling operation, and a counter flow heat exchanger during the heating operation.

In FIG. 1, during cooling operation, the use side heat exchanger 3 on the upstream side of the use fluid circuit is a counter-flow type heat exchanger, and the use side heat exchanger 4 on the downstream side is a parallel flow type heat exchanger. Become. In the heating operation, the use side heat exchanger 3 upstream of the use fluid circuit is used.
Is a parallel flow type heat exchanger, and the downstream use side heat exchanger 4 is a counter flow type heat exchanger. In this case, the heat exchange between the refrigerant and the use fluid is as shown in FIG. 17. In the cooling operation, the downstream side where the use fluid temperature is low becomes the parallel-flow heat exchanger. The temperature difference is hardly generated, the temperature of the used fluid outlet is not excessively lowered, and freezing is hardly performed. Also, during the heating operation, the downstream side where the used fluid temperature is high is the counter-flow type heat exchanger, so there is a temperature difference compared to the parallel flow type heat exchanger, the refrigerant condensation temperature decreases, and the high pressure decreases. Therefore, efficient operation is possible.

In FIG. 2, during the cooling operation, the use side heat exchanger 3 on the upstream side of the use fluid circuit is a parallel flow type heat exchanger, and the use side heat exchanger 4 on the downstream side is a counter flow type heat exchanger. Container. In the heating operation, the use side heat exchanger 3 on the upstream side of the use fluid circuit is a counter-flow type heat exchanger, and the use side heat exchanger 4 on the downstream side is a parallel flow type heat exchanger. In this case, the heat exchange between the refrigerant and the use fluid is as shown in FIG. 18. In the cooling operation, the upstream side where the temperature of the use fluid is high is a parallel flow heat exchanger, and the downstream side where the temperature is low is a counter flow heat exchanger. Therefore, it is possible to balance the locations where the respective refrigerant outlet temperatures are close to each other and to perform an efficient operation.

FIG. 3 shows an example in which the pressure reducing devices 5a and 5b are installed in the refrigerant circuits connected in parallel, respectively, and the adjustment becomes easy.

FIG. 4 shows another embodiment of the heat pump type air conditioner having a plurality of refrigeration cycles shown in FIG. 1 in which fluid circuits to be used for each refrigeration cycle are connected in parallel.

FIG. 5 shows still another embodiment, which is a heat pump type air conditioner using two cycles. The first cycle includes the compressor 1a, the exhaust heat exchanger 2a, the use heat exchanger 3, the expansion valve 5a, and the four-way valve 6a. The second cycle includes the compressor 1b, the exhaust heat exchanger 2b, It has a use-side heat exchanger 4, an expansion valve 5b, and a four-way valve 6b, and the use fluid circuits of the use-side heat exchangers 3, 4 in each cycle are connected in series.

The solid lines and dotted lines of the four-way switching valves 6a and 6b indicate the states during the cooling operation and the heating operation, respectively. FIG.
The solid and dotted arrows in the middle indicate the flow directions of the refrigerant during cooling and during heating, respectively.

In the case of cooling, the high-temperature and high-pressure gas refrigerant compressed by the compressors 1a and 1b respectively receives the four-way switching valves 6a and 6a.
6b, the exhaust heat-side heat exchangers 2a,
2b, is condensed into high-temperature and high-pressure liquid refrigerant, decompressed by expansion valves 5a and 5b, respectively, is evaporated by utilization side heat exchangers 3 and 4, each of which is a laminated plate heat exchanger, and becomes low-temperature and low-pressure gas refrigerant. 1a, 1b
Return to

In the case of the heating operation, the four-way switching valves 6a, 6b
Is switched to the position indicated by the dotted line. Thus, the compressors 1a, 1
The high-temperature and high-pressure gas refrigerant compressed in b flows into the use side heat exchangers 3 and 4 through the dotted line paths of the four-way switching valves 6a and 6b, respectively. At this time, it becomes high-temperature and high-pressure liquid refrigerant by the use side heat exchangers 3 and 4, and the expansion valves 5a and 5b respectively.
, And flows into the exhaust heat-side heat exchangers 2a and 2b to be heat-exchanged to become low-temperature and low-pressure gas refrigerant, which returns to the compressors 1a and 1b, respectively.

FIG. 5 shows two use side heat exchangers 3, 4
During cooling operation, the use-side heat exchanger 3 upstream of the use fluid circuit
So that the counter-flow type heat exchanger and the downstream side use side heat exchanger 4 become a parallel flow type heat exchanger, and in the heating operation, the use side heat exchanger 3 on the upstream side of the use fluid circuit is parallelized. The use fluid circuits are connected in series so that the flow type heat exchanger and the downstream use side heat exchanger 4 become a counter flow type heat exchanger. In this case, the heat exchange between the refrigerant and the used fluid is as shown in FIG. 19, and the same effect as the refrigeration cycle shown in FIG. 1 can be obtained.

In FIG. 6, the two use side heat exchangers 3 and 4 are used during the cooling operation, and the use side heat exchanger 3 upstream of the use fluid circuit is used during the cooling operation. The downstream side use side heat exchanger 4 is a counter-flow type heat exchanger. During the heating operation, the upstream side use side heat exchanger 3 of the use fluid circuit is a counter flow type heat exchanger, and the downstream side use side heat exchanger. The use fluid circuits are connected in series so that the use side heat exchanger 4 becomes a parallel flow type heat exchanger. In this case, the heat exchange between the refrigerant and the used fluid is as shown in FIG. 20, and the same effect as the refrigeration cycle shown in FIG. 2 can be obtained.

FIG. 7 shows still another embodiment of the present invention, which shows a cycle configuration of a one cycle machine of a refrigerating apparatus, and includes a compressor 1, a heat exchanger 2 on the exhaust heat side, heat exchangers 3 and 4 on the use side. The high-temperature and high-pressure gas refrigerant compressed by the compressor 1 is condensed by the exhaust-side heat exchanger 2 to become a high-temperature and high-pressure liquid refrigerant, and is decompressed by the expansion valve 5. Is evaporated by the use-side heat exchangers 3 and 4 to form a low-temperature low-pressure gas refrigerant, and returns to the compressor 1.

In FIG. 7, two use side heat exchangers 3,
The use fluid circuits are connected in series such that the use heat exchanger 3 on the upstream side of the use fluid circuit is a counter-flow heat exchanger and the use heat exchanger 4 on the downstream side is a parallel flow heat exchanger. Connected. In this case, the heat exchange between the refrigerant and the used fluid is performed during the cooling operation shown in FIG. 17, and the same effect as the cooling operation of the refrigeration cycle shown in FIG. 1 can be obtained.

FIG. 8 shows two use side heat exchangers 3 and 4, a use side heat exchanger 3 on the upstream side of the use fluid circuit, a parallel flow type heat exchanger, and a use side heat exchanger 4 on the downstream side. The fluid circuits are connected in series so as to form a counter-flow heat exchanger.
In this case, the heat exchange between the refrigerant and the used fluid is performed during the cooling operation shown in FIG. 18, and the same effect as the cooling operation of the refrigeration cycle shown in FIG. 2 can be obtained.

FIG. 9 shows still another embodiment, which shows a cycle configuration of a two-cycle machine of a refrigeration system,
The high-temperature and high-pressure gas refrigerant compressed by a and 1b are condensed by the exhaust heat-side heat exchangers 2a and 2b to become high-temperature and high-pressure liquid refrigerant, respectively, and decompressed by the expansion valves 5a and 5b, respectively.
Evaporated by the use side heat exchangers 3 and 4 formed by the laminated plate type heat exchangers to become low-temperature low-pressure gas refrigerants,
Return to the compressors 1a and 1b, respectively. At the time of cooling operation, the use side heat exchanger 3 on the upstream side of the use fluid circuit becomes a counter-flow type heat exchanger, and the use side heat exchanger 4 on the downstream side becomes a parallel flow type heat exchanger. The replacement is performed during the cooling operation shown in FIG. 19, and the same effect as the cooling operation of the refrigeration cycle shown in FIG. 3 can be obtained.

FIG. 10 shows two use side heat exchangers 3, 4
The use fluid circuits are connected in series such that the use side heat exchanger 3 on the upstream side of the use fluid circuit is a parallel flow heat exchanger and the use side heat exchanger 4 on the downstream side is a counter flow heat exchanger. In the connected refrigeration apparatus, heat exchange between the refrigerant and the used fluid is as shown in FIG. 20, and the same effect as the cooling operation of the refrigeration cycle shown in FIG. 4 can be obtained.

FIG. 11 shows still another embodiment, which shows a one-cycle machine of a water-cooled heat pump type refrigeration system, in which a use side heat exchanger 3 on the upstream side of a use fluid circuit is a parallel flow type heat exchanger and a downstream side heat exchanger. The use fluid circuits are connected in series so that the use heat exchanger 4 on the side is a counter-flow heat exchanger.

FIG. 12 shows still another embodiment, which shows a two-cycle machine of a water-cooled heat pump refrigeration system, in which high-temperature and high-pressure gas refrigerant compressed by the compressors 1a and 1b are respectively laminated plate heat exchangers. The refrigerant is condensed by the use side heat exchangers 3 and 4 formed in the above, becomes high temperature and high pressure liquid refrigerant, is decompressed by the expansion valves 5a and 5b, respectively, and is evaporated by the exhaust heat side heat exchangers 2a and 2b to become low temperature and low pressure gas refrigerant, respectively. Return to the compressors 1a and 1b, respectively.

[0032]

According to the present invention, it is possible to prevent freezing of the used fluid during the cooling operation, and to achieve a high heat exchange efficiency in both the cooling and heating operations.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of an embodiment according to the present invention.

FIG. 2 is a refrigeration cycle diagram of another embodiment according to the present invention.

FIG. 3 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 4 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 5 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 6 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 7 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 8 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 9 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 10 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 11 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 12 is a refrigeration cycle diagram of still another embodiment according to the present invention.

FIG. 13 is a front view showing a use-side heat exchanger according to one embodiment.

FIG. 14 is an assembly structure diagram of a use side heat exchanger according to one embodiment.

FIG. 15 is a cross-sectional view showing the inside of the use-side heat exchanger in one embodiment.

FIG. 16 is a partial cross-sectional view of a use-side heat exchanger according to one embodiment.

FIG. 17 is a diagram showing heat exchange of a use-side heat exchanger in a refrigeration cycle in one embodiment.

FIG. 18 is a diagram illustrating heat exchange of a use-side heat exchanger in a refrigeration cycle according to another embodiment.

FIG. 19 is a diagram showing heat exchange of a use-side heat exchanger in a refrigeration cycle according to still another embodiment.

FIG. 20 is a diagram showing heat exchange of the use side heat exchanger in the refrigeration cycle in the embodiment of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Exhaust-side heat exchanger, 3, 4 ... Use-side heat exchanger, 5 ... Expansion valve, 6 ... Four-way switching valve, 10a ... Front cover plate, 10b ... Brazing material, 10c ... Channel Plate, 10d ... rear cover plate, 12 ...
Use fluid channel, 12a ... Use fluid upper nozzle, 12b ...
Utilized fluid lower nozzle, 14: refrigerant flow path, 14a: refrigerant upper nozzle, 14b: refrigerant lower nozzle.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F25B 39/00 F25B 39/00 G (72) Inventor Mitsuru Komatsu 390 Muramatsu, Shimizu, Shizuoka Prefecture Hitachi, Ltd. System Shimizu Production Headquarters (72) Inventor Koji Ito 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Hitachi Air Conditioning Systems Shimizu Production Headquarters F-term (reference) 3L054 BF02 BF03 3L092 AA02 AA09 BA13 CA04

Claims (5)

[Claims] 1. A refrigeration cycle in which a compressor, an exhaust-side heat exchanger, a plurality of use-side heat exchangers, and a pressure reducing device are connected by piping.
In the air conditioner provided with a use fluid circuit that connects the plurality of use-side heat exchangers and an air conditioning load, the plurality of use-side heat exchangers connected in parallel as the refrigeration cycle, and the plurality of use-side heats And a flow of the refrigerant of the refrigeration cycle and a flow of the use fluid of the use fluid circuit, wherein one of the plurality of use-side heat exchangers is in a parallel flow. An air conditioner, characterized in that the other is in counter flow. 2. An air conditioner according to claim 1, wherein said plurality of use-side heat exchangers are laminated plate heat exchangers. 3. The air conditioner according to claim 1, wherein an upstream side of the use fluid is a parallel flow, and a downstream side is a counter flow. 4. The apparatus according to claim 1, wherein an upstream side of the use fluid is a parallel flow and a downstream side is a counter flow in a cooling operation, and a downstream side of the use fluid is an upstream in a counter flow in a heating operation. An air conditioner characterized by having a parallel flow. 5. A plurality of refrigeration cycles each having a pipe connected to a compressor, a heat-exchanger-side heat exchanger, a use-side heat exchanger, and a pressure reducing device.
In an air conditioner including a use fluid circuit that connects an air conditioner load and a use side heat exchanger in the plurality of refrigeration cycles, the use side heat exchanger is a laminated plate heat exchanger, An air conditioner, wherein a flow of a flow and a flow of a use fluid of the use fluid circuit are such that one is a parallel flow and the other is a counterflow in the use-side heat exchanger of each of the refrigeration cycles.