US3779031A

US3779031A - Air-conditioning system for cooling dehumidifying or heating operations

Info

Publication number: US3779031A
Application number: US00173037A
Authority: US
Inventors: M Akiyama; S Suzuki
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1970-08-21
Filing date: 1971-08-19
Publication date: 1973-12-18
Anticipated expiration: 1990-12-18

Abstract

An air conditioner comprising a compressor, an outdoor heat exchanger, a first indoor heat exchanger, a second indoor heat exchanger, a first capillary tube, a second capillary tube, a third capillary tube, a first valve, a second valve and a piping communicating said elements with each other, said compressor communicating with one side of said outdoor heat exchanger and said first indoor heat exchanger, the other side of said outdoor heat exchanger communicating with one side of said first capillary tube and said second capillary tube, the other side of said first capillary tube communicating with the other side of said first indoor heat exchanger, the other side of said second capillary tube communicating with one side of said second indoor heat exchanger, the other side of said second indoor heat exchanger and said compressor communicating with each other by said second valve, a series circuit of said second capillary tube and said second indoor heat exchanger and said first valve being connected in parallel with each other, said third capillary tube being connected between the side of said first indoor heat exchanger closer to said first capillary tube and the side of said second indoor heat exchanger closer to said second capillary tube, said first valve being closed and said second valve being opened during a cooling operation, and said first valve being opened and said second valve being closed during a dehumidifying operation.

Description

United States Patent 1191 Akiyama et al.

[ Dec. 18, 1973 AIR-CONDITIONING SYSTEM FOR COOLING DEHUMIDIFYING OR HEATING [57] ABSTRACT OPERATIONS An air conditioner comprising a compressor, an out- 75 Inventors; Mitsuo Akiyama; sigeyasu Suzuki, door heat exchanger, a first indoor heat exchanger, a be f T chi k second mdoor heat exchanger, a first capillary tube, a

th 0 gr en, Japan second capillary tube, a third capillary tube, a first [73] Assigneez Hitachi, Ltd" T ky Japan valve, a second valve and a piping communicating said [22] Filed; Aug 19, 1971 elements with each other, said compressor communicating with one side of said outdoor heat exchanger [2]] Appl. No.: 173,037 and said first indoor heat exchanger, the other side of said outdoor heat exchanger communicating with one [30] Foreign Application priority Data side of said first capillary tube and said second capil- Aug 2| 1970 18 an 45/82845 lary tube, the other side of said first caplllary tube Sept' 1970 Japan 45/93953 communicating with the other side of said first indoor Dec 23 970 "45/128957 heat exchanger, the other side of said second capillary p tube communicating with one side of said second in- [52] U S C 62/160 62/173 62/199 door heat exchanger, the other side of said second in 62/324 door heat exchanger and said compressor communi- [51] Int Cl Fzsb 13/00 eating with each other by said second valve, a series [58] Field 160 324 circuit of said second capillary tube and said second 6 indoor heat exchanger and said first valve being connected in parallel with each other, said third capillary tube being connected between the side of said first in- [56] References Cited door heat exchanger closer to said first capillary tube UNITED STATES PATENTS and the side of said second indoor heat exchanger 2,932,178 4/1960 Armstrong 62/173 closer t Said second capillary tube, said first valve gig-2;": g 'f being closed and said second valve being opened dur er ing a cooling operation, and said first valve being 3,460,353 8/1969 Ogata 62/324 opened and said Second valve being closed during a Primary ExaminerMeyer Perlin dehumidlfymg operauon' Att0rneyCraig, Antonelli & Hill 4 Claims, 14 Drawing Figures COMPRESSOR 9 1' \J 8 l 7* FIRST SECOND 2 INDOOR HT INDOOR H 7' /0 l EXCHANGE/P EXCHANGE? our 000/? 5 6 FAN i 8 Hr mmtzm EX CHANGER g E W FA/V 1 s 1 a 1 3 4 AIR-CONDITIONING SYSTEM FOR COOLING DEHUMIDIFYING OR HEATING OPERATIONS BACKGROUND OF THE INVENTION This invention relates to an air conditioner capable of cooling operation and dehumidifying operation.

In a conventional air conditioner of the type described, two spaced indoor heat exchangers have been connectedin series witheachother as shown in FIGS. 1 and 2 of the. accompanying drawing, and therefore, there has been the disadvantage that a loss of the cooling capacity of a refrigerant due to the flow resistance during passage of the coolant through these heat exchangers is great during the cooling operation and hence the cooling efficiency of the air conditioner is substantially degraded.

SUMMARY OF THE. INVENTION The primary object of the present invention, therefore, is to provide an air conditioner in which the loss of cooling capacity due to the flow resistance is reduced, whereby the cooling efficiency is drastically improved.

Namely, according to the present invention there is provided an air conditioner which comprises a compressor, an outdoor heat exchanger, a first indoor heat exchanger, a second indoor heat exchanger, a first capillary tube, a second capillary tube, a third capillary tube, a first valve, a second valve and a piping communicating said elements with each other, said compressor communicating with one side of said outdoor heat exchanger and said first indoor heat exchanger, the other side of said: outdoor heat exchanger communicating with one side of said first capillary tube and said second capillary tube, the other side of said first capillary tube communicatingwith the other side of said first indoor heat exchanger, the other side of said second capillary tube communicating with one side of said second indoor heat exchanger, the other side of said second indoor heat exchanger and said compressor communicating with each other by said second valve, a series circuit of said second capillary tube and said second indoor heat exchanger and said first valve being connected in parallel with each other, said third capillary tube being connected between the side of said first indoor heat exchanger closer to said first capillary tube and the side of said second indoor heat exchanger closer to said second capillary tube, said first valve being closed and said second valve beingopened duringa cooling operation, and said first valve being opened and said second valve being closed during a dehumidifying operation.

Further, according to the present invention there can be obtained an air conditioner capable of heating operation in addition to the cooling and dehumidifying operations, simply by adding a four-way cock to the air conditioner of thechara'cter described above.

Still. further, according to the present invention there can be provided an air conditioner of the character described. above, in which (when the valves are electromagnetic valves) an electric wiring for actuating said valves is simplified and the opening and closing operations of the valves are also simplified, simply by arranging such that the operation of one of the valves can be concurrently controlled by the operation of the other valve.

BRIEF DESCRIPTIONOF THE DRAWING FIG. 1 is the cycle diagram of a conventional air conditioner during a cooling operation;

FIG. 2 is the cycle diagram of the air conditioner of FIG. 1 during a dehumidifying operation;

FIG. 3 is the cycle diagram of a first embodiment of the air conditioner according to the present invention during a cooling operation;

FIG. 4 is the cycle diagram of the air conditioner of FIG. 3 during a dehumidifying operation;

FIG. 5 is the cycle diagram of a second embodiment of the air conditioner of the present invention during a cooling operation;

FIG. 6 is the cycle diagram of the air conditioner of FIG. 5 during a dehumidifying operation;

FIG. 7 is the cycle diagram of the air conditioner of FIGS. 5 and 6 during a heating operation;

FIG. 8 is the cycle diagram ofa third embodiment of I the air conditioner of the present invention during a cooling operation;

FIG. 9 is the cycle diagram of the air conditioner of FIG. 8 during a dehumidifying operation; and

FIGS. 10 and II are vertical sectional views of open ing and closing valves used in the air conditioner of FIGS. 8 and 9 respectively.

FIGS. 12-14 are cycle diagrams ofa further embodiment of the air conditioner of the present invention during cooling operation, dehumidifying operation, and heating operation, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional air conditioner of this type has a refrigeration cycle as shown in FIGS. 1 and 2. During a cooling operation, this cycle is operated with a first valve 26 closed and a second valve 29 opened, and a refrigerant discharged from a compressor 21 releases its heat during passage through an outdoor heat exchanger 22, is reduced in pressure in a capillary tube 23, absorbs heat during passage through a first indoor heatexchanger 27, a second valve 29 (substantially no refrigerant passes through a second capillary tube 25 as the flow resistance in said second capillary tube is greater than that in said valve 29) and a second indoor heat exchanger 28, and returns to the compressor 21 as indicated by the broken line arrows shown in FIG. 1. During a dehumidifyingvoperation, the cycle is operated with the first valve 26 opened and the second valve 29 closed, and the refrigerant discharged from the compressor 21 releases its heat during passage of i r the outdoor heat exchanger 22 (in this case, it is preferable to make small the amount of heat released by the refrigerant by lowering the rate of rotation of an outdoor fan 30) and further releases its heat to the air interior of a room during passage through the first indoor heat exchanger 27, absorbs heat from the air interior of the room during passage through the capillary tube 25 and returns to the compressor 21. as shown in FIG. 2. In such a cycle, since the

indoor heat exchangers

27, 28 are connected in series with each other, during the cooling. operation the refrigerant passing through the first indoor heat exchanger 27 is reduced in pressure by the capillary tube 25 and then passes through the second indoor heat exchanger 28. Therefore, a loss of cooling capacity of the refrigerant due to the flow resistance is great, resulting in a substantial degradation of the cooling efficiency during the cooling operation.

The present invention has been achieved with a view to overcoming such disadvantages of the conventional air conditioner.

Now, the presentinvention will be described in detail hereinafter with reference to embodiments thereof shown in FIGS. 3-. With reference to the first embodiment shown in FIGS. 3 and 4, the air conditioner comprises a compressor 1, an outdoor heat exchanger 2, a first capillary tube 3, a second capillary tube 4, a third capillary tube 5, a first valve 6, a first indoor heat exchanger 7, a second indoor heat exchanger 8, a second valve 9, an outdoor fan and an indoor fan 11. During the cooling operation, the first valve 6 is held closed and the second valve 9 is held opened, so that a cooling cycle is formed in the air conditioner along two paths, one extending from the compressor 1 through the outdoor heat exchanger 2, the first capillary tube 3, the first indoor heat exchanger 7 to the compressor 1, and another extending from the compressor 1 through the outdoor heat exchanger 2, the second capillary tube 4, the second indoor heat exchanger 8, the second valve 9 to the compressor 1, as indicated by the dotted line arrows in FIG. 3. The airs exterior and interior of a room are circulated by the fans 10 and II as indicated by the solid line arrows respectively, whereby the refrigerant cools the air interior of the room during passage through the first and second

indoor heat exchangers

7, 8 and releases its heat to the outside duringpassage through the outdoor heat exchanger 2.

Now, during the dehumidifying operation, the first valve 6 is held opened and the second valve 9 is held closed, and further the outdoor fan 10 is driven at a relatively low rate of rotation, whereby a dehumidifying cycle is formed in the air conditioner, extending from the compressor 1 through the outdoor heat exchanger 2, the first valve 6 (substantially no refrigerant flows through the first and second

capillary tubes

3, 4 as the flow resistances of said capillary tubes are large), the second indoor heat exchanger 8, the third capillary tube 5, the first indoor heat exchanger 7 to the compressor 1, as indicated by the dotted line arrows in FIG. 4. The airs exterior and interior of the room are circulated as indicated by the solid line arrows respectively, whereby the refrigerant cools the air interior of the room during passage through the first indoor heat exchanger 7 and thereby the water present in the air is removed therefrom by said first indoor heat exchanger, and the refrigerantreleases its heat during passage through the outdoor heat exchanger 2. The air cooled byjthe refrigerant is heated again by-the second indoor heat exchanger 8 and returned into the room. Thus, the air interior of the room is dehumidified.

As described above, according to the present invention the individual

indoor heat exchangers

7, 8, during the cooling operation, are connected with each other in parallel by the two

capillary tubes

3, 4. Therefore, the flow resistance ofthc refrigerant passage can be decrease to one-fourth to one-third of that in the case when said heat exchangers are connected in series, and hence the loss of cooling capacity due to flow resistance can be substantially decreased.

Furthermore, according to the present invention there can be provided an air conditioner capable of heating operation in addition to the cooling and dehumidifying operations.

The air conditioner shown in FIGS. 3 and 4 is capable of cooling and dehumidifying operations by using the two

valves

6, 9 in the cooling cycle, but in FIGS. 5, 6 and 7 there is shown an air conditioner as the second embodiment of the invention, which comprises a fourway valve 12 in addition to the

valves

6, 9 and is capable of not only cooling and dehumidifying operations but also heating operation. Namely, during the cooling operation, the first valve 6 is held closed and the second valve 9 is held opened and further the four-way valve 12 is held in the position shown in FIG. 5, whereby a cooling cycle is formed in the air conditioner along two paths, one extending from the compressor 1 through the four-way valve 12, the outdoor heat exchanger 2, the first capillary tube 3, the first indoor heat exchanger 7, the four-way valve 12 to the compressor l, and another extending from the compressor 1 through the four-way valve 12,'the outdoor heat exchanger 2, the second capillary tube 4, the second indoor heat exchanger 8, the second valve 9, the fourway valve 12 to the compressor 1, as indicated by the dotted line arrows in FIG. 5. The airs exterior and interior of the room are circulated by the fans 10, 11 as indicated by the solid line arrows respectively, whereby the refrigerant cools the air interior of the room during passage through the first and second

indoor heat exchangers

7, 8 and releases its heat to the outside during passage through the outdoor heat exchanger 1.

Now, during the dehumidifying operation, the first valve 6 is heldopened and the second valve 9 is held closed and further the outdoor fan 10 is driven at a relatively low rate of rotation, whereby a dehumidifying cycle is formed in the air conditioner, extending from the compressor 1 through the four-way valve 12, the outdoor heat exchanger 2, the first valve 6 (substantially no refrigerant flows through the first and second

capillary tubes

3, 4 as the flow resistances of said capillary tubes are large), the second indoor heat exchanger 8, the third capillary tube 5, the first indoor heat exchanger 7, the four-way valve 12 to the compressor 1, as indicated by the dotted line arrows in FIG. 6. The airs exterior and the interior of the room are circulated by the fans 10, 11 respectively as indicated by the solid line arrows, whereby the air interior of the room is cooled by the refrigerant at the first indoor heat exchanger 7 and at the same time the water present therein is removed therefrom, and then re-heated by the second indoor heat exchanger 8, while the refrigerant releases its heat to the outside during passage through the outdoor heat exchanger 2. Thus, the air interior of the room is dehumidified.

During the heating operation, the four-way valve 12 is placed in the position shown in FIG. 7 and the first valve 6 is held closed and the second valve 9 opened, whereby a heating cycle is formed in the air conditioner along two paths, one extending from the compressor 1 through the four-way valve 12, the first indoor heat exchanger 7, the first capillary tube 3, the outdoor heat exchanger 2, the four-way valve 12 to the compressor 1, and another extending from the compressor 1 through the four-way valve 12, the second valve 9, the second indoor heat exchanger 8, the second capillary tube 4, the outdoor heat exchanger 2, the four-way valve 12 to the compressor 1 as indicated by the dotted line arrows in FIG. 7. The airs exterior and interior of the room are circulated by the fans 10, 11 respectively as indicated by the solid line arrows, whereby the refrigerant absorbs heat from the outside during passage through the outdoor heat exchanger 2 and heats the air interior of the room during passage through the first and second

indoor heat exchangers

7, 8.

As described above on the second embodiment, accordingto the present invention it is possible to render the air conditioner capable of heating operation, which comprises two valves and is capable of cooling and dehumidifying operations, merely by adding a four-way valve to said air conditioner.

The third embodiment of the invention will be described with reference to FIGS. 8, 9, and 11. In the 7 first and second embodiments described above, there i are provided two

valves

6, 9 and these valves must be operated individually. However, the third embodiment of the air conditioner shown in FIGS. 8, 9, l0 and 11 comprises means by which one of the two valves in the preceding embodiments is automatically opened or closed when the other one is operated. Where the valves are electromagnetic valves, the incorporation of such means is advantageous in simplifying an electric circuit to operate the valves and simplifying the operation of said valves since both valves can be operated by operating only one of them.

The air conditioner according to this embodiment, as shown in FIGS. 8 and 9, comprises a compressor 1, an outdoor heat exchanger 2, a first capillary tube 3, a second capillary tube 4, a third capillary tube 5, a first operating valve 6 such as an electromagnetic valve, a first indoor heat exchanger 7, a second indoor heat exchanger 8, a three-way valve 19 that is a second valve not comprising operating parts such as electromagneticallycontrolled parts, an outdoor fan 10 and an indoor fan 11. The details of the three-way valve 19 are shown in FIGS. 10 and 11 in which

reference numerals

40, 41, 42 designate pipes connected to the three-way valve 19; 43 a piston slidably received in said valve; and 44 a fine channel axially bored through said piston.

During the cooling operation, the first operating valve 6 such as an electromagnetic valve is held closed, whereby the piston 44 in the three-way valve 19 that is the second valve is held in the position shown in FIG. 10 (the piston 44 moves down under gravity when the three-way valve 19 is mounted in such a manner that the pipe 40 extends upwardly therefrom), so that the refrigerant flows from the pipe 40 into the pipe 41. Thus, a cooling cycle is formed along two paths, one extending from the compressor 1 through the outdoor heat exchanger 2, the first capillary tube 3, the first indoor heat exchanger 7 to the compressor 1, and another extending from the compressor 1 through the outdoor heat exchanger 2, the second capillary tube 4, the second indoor heat exchanger 8, the three-way valve 19 to the compressor 1, as indicated by the dotted line arrows in FIG. 8. The airs exterior and interior of the room are circulated by the fans 10, 11 respectively as indicated by the solid line arrows, whereby the refrigerant cools the air interior of the room during passage through the first ahd second

indoor heat exchangers

7, 8 and releases its heat to the outside during passage through the outdoor heat exchanger 2.

On the other hand, during the dehumidifying operation the operating valve 6 such as an electromagnetic valve is held opened and hence the piston 44 is the three-way valve 19 is held in the elevated position shown in FIG. 11 since the pressure of the refrigerant in the pipe 42 becomes higher than that in the

pipes

40, 41. Thus, the communication between the pipes 42, and the pipe 41 is shut down and the refrigerant flows from the pipe 42 into the pipe 40 through the axial channel 44 in the piston 43. Namely, adehumidifying cycle is formed in the air conditioner, extending from the compressor 1 through the outdoor heat exchanger 2, the electromagnetic valve 6, the three-way valve 19, the second indoor heat exchanger 8, the third capillary tube 5, the first indoor heat exchanger 7 to the compressor 1, as indicated by the dotted line arrows in FIG. 9. The airs exterior and interior of the room are circulated by the fans 10, 11 respectively as indicated by the solid line arrows, whereby the air interior of the room is cooled and at the same time the water present therein is removed by the first indoor heat exchanger 7, and reheated by the second indoor heat exchanger 8 and returned into the room, while the heat of the refrigerant is slightly released to the outside at the outdoor heat exchanger 2. Thus, the air interior of the room is dehumidified. A further embodiment of the invention is described with reference to FIGS. 12, 13, and 14, wherein the same reference numerals are used to describe similar parts as above. In this embodiment, as described with the second embodiment above in FIGS. 57, a fourway valve 12 is provided which allows a heating operation, together with cooling and dehumidifying operations. Furthermore, a second. valve 19, which is a three-way valve, as described in FIGS. 10 and 11, is used as the second valve. As discussed above with regard to FIGS. 8 and 9, this three-way valve provides the advantage of having its operation effected by the operation of valve 6. Therefore, when valve 6 is open, the three-way valve 19 is automatically closed by the action of the refrigerant pressure entering pipe 42. On the other hand, when valve 6 is closed, the piston 43 (as seen in FIG. 10) moves down under gravity, allowing the flow of the refrigerant through pipe 40 into pipe 41.

Accordingly, in the cooling operation, the valve 6 is closed, and the three-way valve 119 is in the position shown in FIG. 10, since the piston 43 is in its lower position under the action of gravity. The refrigerant in the pipe 40 flows into the pipe 41, with the result that the refrigerant in the cycle flows, as indicated by the dotted line arrow in FIG. 12. t

In the dehumidifying operation, as shown in FIG. 13, the valve 6 is open, so that the pressure of refrigerant in the pipe 42 becomes higher than that in the

pipes

40 and 41 and the piston 43 in the three-way valve 19 is pushed up to the operative position shown in FIG. 11. The refrigerant in the pipe 42 flows into the pipe 40 through the channel 44 at the center of the piston 43. The refrigerant in this cycle flows as indicated by the dotted line arrow in FIG. 13.

In the heating operation, the four-way valve is shifted to the position shown in FIG. 14. The valve 6 is closed. In this case, the piston 43 of the three-way valve 19 moves down under gravity to the position shown in FIG. 10, and the refrigerant in the pipe 41 flows into the pipe 40. The refrigerant in this cycle then flows as indicated by the dotted line arrow in FIG. 14.

We claim:

1. An air conditioner comprising a compressor, an outdoor heat exchanger, a first indoor heat exchanger, a second indoor heat exchanger, a first capillary tube, a second capillary tube, a third capillary tube, a first valve, a second valve and a piping communicating said elements with each other, said compressor communicating with one side of said outdoor heat exchanger and said first indoor heat exchanger, the other side of said outdoor heat exchanger communicating with one side of said first capillary tube and said second capillary tube, the other side of said first capillary tube tibe communicating with the other side of said first indoor heat exchanger, the other side of said second capillary tube communicating with one side of said second indoor heat exchanger, the other side of said second indoor heat exchanger and said compressor communicating with eachother by said second valve, a series circuit of said second capillary tube and said second indoor heat exchanger and said first valve being connected in parallel with each other, said third capillary tube being connected between the side of said first indoor heat exchanger closer to said first capillary tube and the side of said second indoor heat exchanger closer to said second capillary tube, said first valve being closed and said second valve being opened during a cooling operation, and said first valve being opened and said second valve being closed during a dehumidifying operation.

2. An air conditioner as defined in claim 1, wherien a four-way valve is disposed between the compressor,

and the outdoor heat exchanger and the first indoor heat exchanger.

3. An air conditioner as defined in claim 2, wherein said second valve is a three-way valve including a first pipe communicating with said first valve; a second pipe communicating with said second indoor heat exchanger; a third pipe, operatively connected to said compressor; and a piston, operatively movable by pressure differential of a refrigerant, such that said refrigerant flows between said first pipe and said second pipe, when said first valve is open, and said refrigerant flows between said second pipe and said third pipe, when said first valve is closed.

4. An air conditioner as defined in claim 1, wherein said second valve is a three-way valve including a first pipe communicating with said first valve; a second pipe communicating with said second indoor heat exchanger; a third pipe, operatively connected to said compressor; and a piston, operatively movable by pressure differential of a refrigerant, such that said refrigerant flows between said first pipe and said second pipe, when said first valve is open, and said refrigerant flows between said second pipe and said third pipe, when said first valve is closed.

Claims

1. An air conditioner comprising a compressor, an outdoor heat exchanger, a first indoor heat exchanger, a second indoor heat exchanger, a first capillary tube, a second capillary tube, a third capillary tube, a first valve, a second valve and a piping communicating said elements with each other, said compressor communicating with one side of said outdoor heat exchanger and said first indoor heat exchanger, the other side of said outdoor heat exchanger communicating with one side of said first capillary tube and said second capillary tube, the other side of said first capillary tube tibe communicating with the other side of said first indoor heat exchanger, the other side of said second capillary tube communicating with one side of said second indoor heat exchanger, the other side of said second indoor heat exchanger and said compressor communicating with each other by said second valve, a series circuit of said second capillary tube and said second indoor heat exchanger and said first valve being connected in parallel with each other, said third capillary tube being connected between the side of said first indoor heat exchanger closer to said first capillary tube and the side of said second indoor heat exchanger closer to said second capillary tube, said first valve being closed and said second valve being opened during a cooling operation, and said first valve being opened and said second valve being closed during a dehumidifying operation.

2. An air conditioner as defined in claim 1, wherien a four-way valve is disposed between the compressor, and the outdoor heat exchanger and the first indoor heat exchanger.