JPH03152355A - Air conditioner - Google Patents

Abstract

PURPOSE:To selectively room cool or heat at each indoor unit and to simultaneously room cool at one indoor unit and heat at the other indoor unit by providing first and second branch units and check valves, and providing second and third flow rate controllers. CONSTITUTION:In the case of concurrent room cooling and heating with main room cooler, high pressure gas refrigerant is introduced from a first connection tube 6, a first branch unit 10 into indoor units to room heat to conduct room heating, then the refrigerant is fed from a second branch unit 11 partly to an indoor unit to be room cooled to conduct room cooling, and fed from the unit 10 to a second connection tube 7. In the case of only room heating, the refrigerant is fed from a heat source unit A to each indoor unit through the tube 6 and the unit 10 to room heat, and returned from the unit 11 to a heat source unit through the tube 7. Second and third flow rate controllers 13, 15 are so controlled that the detection pressure difference between pressure detectors falls within a predetermined range. Thus, one indoor unit room cools and the other indoor unit simultaneously room heats.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a multi-room heat pump air conditioner in which a plurality of indoor units are connected to one heat source unit, and in particular, The present invention relates to an air conditioner that can perform heating and cooling selectively, and can simultaneously perform cooling with one indoor unit and heating with the other indoor unit.

[Conventional technology]

Conventionally, heat pump air conditioners have been common in which multiple indoor units are connected to one heat source unit using two pipes, a gas pipe and a liquid pipe, and each indoor unit performs cooling and heating operation. or all were designed to provide heating.

[Problem to be solved by the invention]

Conventional multi-room heat pump air conditioners are configured as described above, and all the indoor units operate only in either the El air conditioner or the air conditioner mode, so that heating is performed in areas that require cooling, or vice versa. There was a problem where cooling was performed in places that needed heating. In particular, when installed in a large building, the air conditioning load is significantly different between the interior area and the perimeter area, or between a general office and a computer room, which is a big problem.

This invention was made to solve the above-mentioned problems, and it connects multiple indoor units to one heat source unit, and selectively performs air conditioning and heating for each indoor unit, and only one of the indoor units. The indoor unit can perform cooling and the other indoor unit can perform heating at the same time, and when installed in a large building, it can be used in the interior and perimeter areas, or in OA rooms such as general offices and computer rooms. The purpose of the present invention is to obtain a multi-chamber heat pump type air conditioner that can cope with significantly different air conditioning loads.

[Means to solve the problem]

In the air conditioner according to the present invention, one of the indoor units is connected to the first
and a first branching part having a valve device switchably connected to the second connecting pipe, a second branching part connecting the other of each indoor unit to the second connecting pipe, and a second branching part. A second flow control section provided between the second connection pipe and one end connected to the second connection pipe.
The first and second flow rates are connected to the branch part of the first and second check valves, the other end of which allows flow only to the third flow rate control part and the first and second connection pipes, respectively. Provided in a pipeline between a bypass pipe connected to the connection pipe, a first pressure detection unit provided in the first connection pipe to detect the pressure, and second and third flow rate control units, A second pressure detection section that detects the pressure, and a flow rate control section control that controls the second and third flow rate control sections so that the detected pressure difference of each pressure detection section is within a predetermined range during heating only operation. This means that a means has been established.

[For production]

In this invention, in the case of simultaneous cooling and heating operation mainly consisting of heating, high-pressure gas refrigerant is introduced from the first connection pipe and the first branch to each indoor unit to be heated, and then the refrigerant is transferred to the second A part of the branch part flows into the indoor unit that is trying to cool the room and performs cooling, and from the first branch part to the second
into the connecting piping. On the other hand, the remaining refrigerant passes through the second flow rate control section and joins with the refrigerant that has passed through the cooling indoor unit.
It flows into the connecting piping and returns to the heat source equipment.

In addition, in the case of mainly cooling, high-pressure gas is exchanged with a heat source device in an arbitrary amount to form a two-phase state, and a gaseous refrigerant is supplied from the second connecting pipe to the indoor unit that is to be heated via the first branch. The refrigerant is introduced to perform heating, and the pressure of the refrigerant is slightly reduced in the first flow rate control section, and the refrigerant flows into the second branch section. On the other hand, the remaining liquid refrigerant passes through the second flow rate control section, joins with the refrigerant that has passed through the heating indoor unit at the second branch, and flows into each indoor unit to be cooled to perform cooling. It returns to the compressor from the branch part through the first connection pipe.

In addition, in the case of only heating operation, the refrigerant flows from the heat source device through the first connecting pipe and the first branch to each indoor unit, heats it, and then flows from the second branch to the second connecting pipe. and return to the heat source machine. Further, the second and third flow rate control units are controlled so that the detected pressure difference of each pressure detection unit is within a predetermined range.

In addition, in the case of cooling only, the refrigerant is introduced from the heat source device through the second connection pipe and the second branch to each indoor unit, cooled, and then passed from the first branch to the first connection pipe. Return to the heat source machine.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows an overall configuration diagram centered on the refrigerant system of an air conditioner according to the first embodiment of the present invention, FIG. 2 shows an operating state diagram of only cooling or heating, and FIG. Fig. 4 is a diagram showing the state during simultaneous heating and cooling operation of the cooling main unit (when the heating operating capacity is larger than the cooling operating capacity). It is.

In FIG. 1, A is a heat source device, B-D is an indoor unit with the same configuration, and E is a relay device that relays between the heat source device A and the indoor units B-D. In the heat source machine A, 1 is a compressor that compresses refrigerant, 2
3 is a four-way valve that switches the refrigerant flow direction; 3 is a heat exchanger on the heat source side that exchanges heat between air and refrigerant; 4 is an accumulator that accumulates pressure; these are connected by a refrigerant pipe.

5 is an indoor heat exchanger provided in each indoor unit B-D, 6 is a first connection pipe connecting the four-way valve 2 and the relay machine E, and 6b to
6d is a connection pipe that connects the heat exchanger 5 of each indoor unit E-D and the repeater E, 7 is a second connection pipe that connects the heat exchanger 3 and the repeater E, and 7b to 7d are the indoor units B. -D heat exchanger 5
This is a connection pipe that is connected via the first flow rate control unit 9 and also to the repeater E, and the flow rate control unit 9 is provided close to the heat exchanger 5, and when cooling the outlet side, the super The amount of heat is controlled by the amount of subcooling during heating.

Further, 8 is a three-way switching valve that switchably connects the connecting pipes 6b to 6d and the connecting pipe 6 or the connecting pipe 7 side, and the connecting pipe portion including each of the three-way switching valves 8 is connected to the first branch part 10.
form. Reference numeral 11 denotes a second branch part that connects the connecting pipes 7b to 7d with the connecting pipe 7 side, 12 represents a gas-liquid separation part provided in the middle of the connecting pipe 7, and the gas layer part is connected to the 108a of the three-way switching valve 8. The liquid layer portion is connected to the branch portion ll side. 13 is a second flow control unit (here, an electric expansion valve) provided between the gas-liquid separation unit 12 and the branching unit 11;
14 is a bypass pipe connecting the branch part 11 and the connecting pipe 6°7, 15 is a third flow control part (here, an electric expansion valve) provided in the middle of the bypass pipe 14, and 16a to 16d.
1 is a heat exchange section provided between the pipes in the branch section 11;
A check valve 718 is provided between the bypass pipe 14 and the connecting pipe 6.7, and allows the refrigerant to flow only in the direction from the bypass pipe 14 to the connecting pipe 6.7. 25 is a first pressure detection section provided in the connecting pipe 6, and 26 is a pressure detection section provided in the pipe line between the flow rate control sections 13 and 15.

Next, the operation of the above configuration will be explained. FIG. 2 shows the operating state of only cooling or heating, and first the cooling operating state will be explained. That is, as shown by the solid arrow, the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, undergoes heat exchange in the heat exchanger 3, and is condensed and liquefied.
It passes through the gas-liquid separation part 12 and the flow rate control part 13, and further passes through the branch part 11 and the connection pipes 7b to 7d, and flows into each of the indoor units B to D. The refrigerant that has flowed into each indoor unit B-D is reduced in pressure to a low pressure by a flow rate control section 9 that is controlled by the amount of superheat on the outlet side of each heat exchanger 5, and then heat exchanged with indoor air by the heat exchanger 5. , evaporates into gas and cools the room. The gasified refrigerant is sucked into the compressor 1 through the connecting pipes 6b to 6d, the three-way switching valve 8, the branch part 10, the connecting pipe 6, the four-way valve 2, and the axemulator 4. At this time, the 108a of the three-way switching valve 8 is closed, the 208b, and the 308th
c is open circuit.

Further, in the cooling cycle, a part of the refrigerant that has passed through the flow rate control section 13 enters the bypass pipe 14, is reduced in pressure to a low pressure by the flow rate control section 15, and is also transferred to the heat exchange sections 16a to 16.
At d, heat exchange is performed with the connection pipes 7b to 7d and the confluence side of the branch part 11, and the evaporated refrigerant enters the connection pipe 6 via the check valve 17, and passes through the four-way valve 2 and the accumulator 4. It is sucked into the compressor 1. At this time, since the connecting pipe 6 is under low pressure and the connecting pipe 7 is under high pressure, the check valve 17 is inevitably opened. On the other hand, the refrigerant cooled in the heat exchange parts 16'a to 16d and sufficiently subcooled flows into the indoor units BD through the connection pipes 7b to 7d. Note that, at this time, the connection pipes 7b to 7d are filled with liquid refrigerant.

Next, the case of only heating operation will be described using FIG. 2. That is, as shown by the dotted line arrow, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2, the connecting pipe 6, the branch part 10, the three-way switching valve 8, and the connecting pipes 6b to 6d to each indoor unit B. -D, it exchanges heat with indoor air, condenses into liquid, and heats the room. The liquefied refrigerant is controlled by the sub-cooling amount at the outlet of the heat exchanger 5, passes through the flow rate control unit 9 which is in an almost fully open state, flows into the branch unit 11 via the connecting pipes 7b to 7d, joins the flow rate control unit 13, and flows through the flow rate control unit 13. Pass.

The flow rate control units 13 and 15 are controlled so that the refrigerant remains in a liquid state even after pressure reduction in the flow rate control unit 9, and the refrigerant enters a two-phase state for the first time after pressure reduction in the second and third flow rate control units 13.15. .

Thereby, the connecting pipes 7b to 7d are filled with liquid refrigerant. The connecting pipes 7b to 7d are filled with liquid refrigerant even in the case of only cooling operation, but the connecting pipes 7b to 7d are filled with liquid refrigerant in case of only heating operation.
When the flow rate control unit 13 is controlled so that the refrigerant b to 7d are in a two-phase state, the refrigerant specific gravity is smaller than the mass refrigerant amount held in the connection piping 7b to 7d in the case of cooling operation only. The amount of refrigerant decreases, and the amount of liquid refrigerant stored in the accumulator 4 as surplus refrigerant increases. However, in this embodiment, since the refrigerant in the connecting pipes 7b to 7d is in a liquid state, the mass amount of refrigerant held in the connecting pipes 7b to 7d is not much different from that in the case of only cooling operation.
There is not much surplus refrigerant, the capacity of the accumulator 4 can be reduced, liquid backflow to the compressor 1 is also small, and reliability of the compressor 1 can be improved. The refrigerant that has been reduced in pressure to a low pressure flows into the heat exchanger 3 via the gas-liquid separation section 12 and the connecting pipe 7, and the refrigerant that has evaporated into a gas state through heat exchange is passed through the four-way valve 2 and the accumulator 4 to the compressor 1. is inhaled.

Note that the opening and closing of the three-way switching valve 8 is the same as in the case of only cooling operation.

Next, a case in which heating is the main component in simultaneous cooling and heating operation will be described using FIG. 3. That is, as shown by the dotted arrow, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2.
, is sent to the relay machine via the connecting pipe 6, and is sent to the branch part 10,
It flows through the three-way switching valve 8 and the connecting pipes 6b and 6c into each of the indoor units B and C to be heated, exchanges heat with indoor air in the heat exchanger 5, and is condensed and liquefied to heat the room. The condensed and liquefied refrigerant passes through the flow control section 9, which is in a substantially fully open state controlled by the subcooling amount at the outlet of each heat exchanger 5, and is slightly depressurized, and flows into the branch section 11 via the connecting pipes 7b and 7c. A part of this refrigerant enters the indoor unit to be cooled through the connecting pipe 7d, enters the flow rate control section 9 controlled by the amount of super heat at the outlet of the heat exchanger 5, and is depressurized, after which it is heat exchanged. The gas enters the vessel 5, exchanges heat, evaporates, becomes a gas, cools the room, and flows into the gas-liquid separator 12 via the three-way switching valve 8. On the other hand, other refrigerants flow into the gas-liquid separation section 12 through the flow rate control section 13, join with the refrigerant that has passed through the indoor unit, flow into the connecting pipe 7, and flow into the heat exchanger 3 for heat exchange. It evaporates and becomes a gas. Furthermore, the refrigerant is sucked into the compressor 1 through the four-way valve 2 and the accumulator 4. In this heating-based operation, the 108a of the three-way switching valve 8 connected to the indoor units B and C is closed, and the 208b
and 308C are open, 208b of the three-way switching valve 8 connected to indoor 1SID is closed, and 108a and 308C are open.

Also, during this cycle, some liquid refrigerant flows through the connecting pipes 7b to 7.
It enters the bypass pipe 14 from the confluence part of C, and the flow rate control part 1
5, the pressure is reduced to low pressure in the heat exchange parts 16a to 16d, and evaporates through heat exchange, and then passes through the check valve 18, enters the connecting pipe 7, flows into the heat exchanger 3, exchanges heat, and evaporates. It becomes a gas state. This refrigerant is further sucked into the compressor 1 via the four-way valve 2 and the accumulator 4. At this time,
Since the connecting pipe 6 is at high pressure and the connecting pipe 7 is at low pressure, the water flows through the check valve 18 side. On the other hand, the refrigerant that has been heat exchanged, cooled, and subcooled in the heat exchange parts 16a to 16c is sufficiently subcooled from the branch part 11 to the heat exchange part 16d, and then flows into the indoor unit.

Next, a case in which air conditioning is mainly used in simultaneous heating and cooling operation will be described using FIG. 4. In this case, as shown by the solid arrow, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way valve 2 and exchanges heat with the heat exchanger 3 to form a two-phase high-temperature, high-pressure state. 7 to the gas-liquid separation section 12
The refrigerant is separated into gaseous refrigerant and liquid refrigerant, and the gaseous refrigerant flows into the indoor unit to be heated via the branch part 10, the three-way switching valve 8, and the connecting pipe 6d, and is heated by the heat exchanger 5. It exchanges heat with the air, condenses and liquefies, heating the room. Further, the refrigerant is controlled by the subcooling amount at the outlet of the heat exchanger 5, passes through the flow rate control section 9 which is in an almost fully open state, is slightly depressurized, and flows into the branch section 11 via the connecting pipe 7d. On the other hand, the liquid refrigerant flows into the branch part 11 through the flow rate control part 13 and merges with the refrigerant that heated the indoor unit.The combined refrigerant flows into the indoor units B and C through the connecting pipes 7b and 7c. The pressure is reduced to a low pressure by the flow control unit 9 controlled by the amount of superheat at the outlet of the heat exchanger 5, and the air is evaporated and gasified through heat exchange with indoor air, thereby cooling the room. The refrigerant in the gas state is transferred to the connecting pipe 6b6c, the three-way switching valve 8, the branch part 10,
The air is sucked into the compressor 1 through the connecting pipe 6, the four-way valve 2, and the accumulator 4. In this air-conditioning-based simultaneous heating and cooling operation, the 108a of the three-way switching valve 8 connected to the indoor unit
, No. 308C is open, No. 208b is closed, and indoor unit B
, C, 208b and 308C are open, and 108a is closed. Also, during this cycle, some liquid refrigerant enters the bypass pipe 14 from the confluence of the connecting pipes 7b to 7d,
The pressure is reduced to a low pressure by the flow rate control section 13 and the heat exchange section 16a-
The refrigerant that has undergone heat exchange and evaporated in step 16d is sucked into the compressor 1 through the check valve 17, the connecting pipe 6, the four-way valve 2, and the accumulator 4. Note that since the connecting pipe 6 has a low pressure and the connecting pipe 7 has a high pressure, the check valve 17 is conductive.

On the other hand, the refrigerant that has been cooled by heat exchange and subcooled in the heat exchange section 16d flows into the branch section 11 and is cooled by heat exchange in the heat exchange section 16d.
The air is further subcooled at a to 16c and flows into the indoor units B and C that are to be cooled.

Next, the control of the flow rate controllers 13 and 15 in the case of only heating operation will be explained. FIG. 6 shows the control B mechanism of the flow rate controller 13.15, and FIG. 7 is a flowchart showing its operation. Reference numeral 40 denotes a flow rate control unit control means for controlling the valve opening degree of the flow rate control unit 13.15 in accordance with the pressure difference detected by the pressure detection unit 25.26. Difference ΔP between the detected pressures of the pressure detectors 25 and 26! is below a certain value ΔP, the refrigerant necessary for heating will not be supplied even if the flow rate control units 9 of indoor units B and C that are attempting to heat the room are fully opened, and due to the pressure difference P
When o exceeds a certain value of 688, even if the liquid refrigerant after passing through the heat exchanger 5 has been sufficiently subcooled, the flow rate controller 9
After the pressure is reduced, the connecting pipes 7b to 7d end up in a gas-liquid two-phase state instead of being in a single-phase liquid state. Therefore, the pressure difference ΔP3!
is ΔP, and the first target pressure difference Δ is set larger in advance.
P1 and a second target pressure difference ΔP□ which is preset smaller than ΔP2, that is, ΔP□≦ΔP3! ≦
By controlling the flow rate control unit 1315 so that ΔP□, it is possible to supply sufficient refrigerant to the indoor units B and C to be heated while filling the connecting pipes 7b to 7d with a single liquid phase.

In step 50 of FIG. 7, the pressure difference Δpsz is calculated, and in step 51, Δpsi is compared with ΔP□, and ΔpSt<
If ΔP□, it is determined in step 52 whether the opening degree of the flow rate control unit 15 is the fully open value, and if it is not the fully open value, step 53
The degree of opening of the flow rate control section 15 is increased in step 54, and if the opening degree is the fully open value, the degree of opening of the flow rate control section 13 is increased in step 54, and the process returns to step 50. On the other hand, ΔP! , ≧ΔP, d, the process proceeds to step 55, where ΔPAM is compared with ΔP□.

If ΔPo>ΔP□, the process proceeds to step 56, where it is determined whether the opening degree of the flow rate control unit 13 is a fully closed value, and if it is not the fully open value, the opening degree of the flow rate control unit 13 is decreased in step 57. If the value is fully closed, the flow rate controller 1 is turned on in step 58.
5 and return to step 50. Also, ΔP! If t≦ΔP'sm, the process also returns to step 50. In this way, the pressure difference ΔF'am can be maintained within a certain range.

In the above embodiment, a three-way switching valve 8 is provided, and the connecting pipes 6, 7 are connected to the connecting pipes 61] to 6d in a switchable manner, but as shown in FIG.
It is also possible to provide a switchable switch.

Further, in each of the above embodiments, the number of indoor units is three, but any number of indoor units may be used as long as it is two or more.

(Effects of the Invention) As described above, according to the present invention, heating and cooling can be performed selectively and simultaneously by providing the first and second branch portions, check valves, and the like. In addition, during heating-only operation, the second and third flow rate controllers are controlled so that the pressure difference between the first connection pipe and the bypass pipe is within a predetermined range, and the indoor unit that is to be heated is In addition to being able to supply sufficient refrigerant, the connecting pipe between the first flow rate control part and the second branch part is filled with liquid refrigerant, and the amount of surplus refrigerant stored in the Akiemulator is small, so the accumulator is It is possible to reduce the capacity, reduce liquid back to the pressure wm machine, and improve the reliability of the compressor.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the refrigerant system configuration of the device of the present invention, Fig. 2 is a diagram showing the operating state of cooling or heating only, Fig. 3 is a state diagram of heating-based simultaneous cooling/heating operation, and Fig. 4 is a state diagram of air-conditioning-based simultaneous cooling/heating operation. FIG. 5 is a block diagram of a refrigerant system according to another embodiment of the apparatus of the present invention, and FIGS. 6 and 7 are block diagrams and flowcharts of the flow control unit control system of the apparatus of the present invention. A... Heat source machine, B-D... Indoor unit, 1... Compressor, 2... Four-way valve, 3... Heat source machine side heat exchanger, 4...
・Accumulator, 5... Indoor heat exchanger, 6...
First connection pipe, 7... Second connection pipe, 7b to 7d
... Connection piping, 8... Three-way switching valve, 9... First flow control section, 10... First branch section, 11... Second
branch part, 13... second flow rate control part, 14... bypass piping, 15... third flow rate control part, 17.18
...Check valve, 25.26...Pressure detection section, 40...
・Flow control unit control means. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] One heat source machine consisting of a compressor, a four-way valve, a heat exchanger on the heat source side and an accumulator, and a plurality of indoor units consisting of an indoor heat exchanger and a first flow rate controller are connected to the first and second In those connected via connection piping, a first branch section having a valve device that connects the indoor heat exchanger side of each indoor unit to the first and second connection piping in a switchable manner; 1st
a second branch part that connects the flow rate control part side of the second connection pipe to the second connection pipe; a second flow control part provided between the second branch part and the second connection pipe; The first and second flow pipes are connected to the second branch part through first and second check valves whose other ends permit flow only to the third flow rate control part and the first and second connection pipes, respectively. a bypass pipe connected to the connecting pipe, a first pressure detection section provided in the first connecting pipe and detecting the pressure thereof, and a pipe between the second flow rate control section and the third flow rate control section. A second pressure detection section is installed in the road and detects the pressure, and a second and third pressure detection section is installed in the air conditioner so that the detected pressure difference between the first and second pressure detection sections is within a predetermined range in heating only operation. An air conditioner comprising a flow rate control section control means for controlling a flow rate control section.