JP2008175430A - Air conditioner - Google Patents

Abstract

An air conditioner capable of switching control of a refrigeration cycle without impairing reliability.
A compressor, an outdoor heat exchanger, an expansion valve, a first indoor heat exchanger that operates as a condenser, a capillary tube, and a second indoor heat exchanger that operates as an evaporator are sequentially connected. The refrigerant that is drawn into the compressor 11 and the refrigerant pipe 25 branched from the main refrigerant flow path between the outdoor heat exchanger 13 and the first indoor heat exchanger 15 and the refrigerant sucked into the compressor 11 are used as a refrigerant. The sub-refrigerant circuit 28 for returning to the original main refrigerant flow path and the electromagnetic two-way valve 19 for controlling the refrigerant flowing into the sub-refrigerant circuit 28, and the indoor air temperature and the temperature set by the user Depending on the difference, the electromagnetic two-way valve 19 is opened and closed, and an optimum refrigeration cycle can be achieved.
[Selection] Figure 1

Description

  The present invention relates to an air conditioner having a reheat dehumidification function.

  Conventionally, in this type of general air conditioner, in a reheat dehumidification mechanism in which an indoor heat exchanger is divided into a plurality (usually two), one is used as a condenser and one as an evaporator, By controlling the opening and closing of the fully-closed expansion valve or electromagnetic two-way valve that connects the condenser and the evaporator, other operation modes such as reheat dehumidification operation and cooling operation were separated. However, in such a configuration, it is difficult to improve the room temperature lowering ability and the sensible heat ability in the indoor unit, so an air conditioner as shown in FIG. 8 has been proposed (for example, see Patent Document 1). ).

  In FIG. 8, the outdoor unit 32 includes a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, an outdoor fan 34 that sends air to the outdoor heat exchanger 13, and an expansion valve 14. Is connected between the first indoor heat exchanger 15 operating as a condenser, the second indoor heat exchanger 18 operating as an evaporator, and the first indoor heat exchanger 15 and the second indoor heat exchanger 18. The capillary tube 16 and the electromagnetic on-off valve 17 are incorporated, and the compressor 11, the four-way valve 12, the outdoor heat exchanger 13, the expansion valve 32, the first indoor heat exchanger 15, the capillary tube 16, the electromagnetic on-off valve 17, The 2nd indoor heat exchanger 18 is connected in order by refrigerant piping 25, and the refrigerating cycle is constituted.

  22, 23, and 24 are temperature sensors that detect the temperatures of the first indoor heat exchanger 15, the second indoor heat exchanger 18, and the outdoor heat exchanger 13, respectively. A temperature sensor 25 detects the temperature of indoor air.

  In the conventional air conditioner, the maximum sensible heat in the refrigeration cycle is adjusted by adjusting the rotational speed of the outdoor blower 34 and the opening of the expansion valve 14 so that the temperature detected by the temperature sensor 22 becomes a predetermined value. Is to be obtained. However, even with such a configuration and control, the sensible heat obtained is about several hundred watts, which is insufficient to lower the room temperature in midsummer.

On the other hand, although not specifically shown, a new two-way solenoid valve was added to the outdoor unit, and heat was exchanged between the high-temperature and high-pressure two-phase refrigerant with the low-temperature and low-pressure compressor suction refrigerant, resulting in subcooling. By returning to the indoor unit as a refrigerant, the condensing capacity in the indoor unit was reduced, and as a result, the room temperature lowering ability and sensible heat capacity in the indoor unit could be greatly improved.
JP 2003-106706 A

  However, in the configuration of the conventional air conditioner, the refrigerant is branched to the liquid-gas heat exchanger for supercooling at the outlet of the first indoor heat exchanger added to increase the ability to lower the room temperature. There has been a problem that there is no control mechanism for optimizing the operation of the electromagnetic two-way valve or the expansion valve that can be fully closed.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide an air conditioner capable of performing optimal refrigeration cycle control without impairing reliability during reheat dehumidification operation.

  In order to solve the above conventional problems, an air conditioner of the present invention includes a compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger. Refrigeration cycle configured to sequentially circulate the refrigerant, refrigerant pipe branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger, and sucked into the compressor A refrigerant circuit that heat-exchanges the refrigerant to be circulated and then returns the refrigerant to the original main refrigerant flow path, and an electromagnetic valve that controls the refrigerant flowing into the sub-refrigerant circuit. In an air conditioner that enables a reheat dehumidifying operation in which one of the exchangers is operated as a condenser and the other as an evaporator, the electromagnetic wave is changed according to a difference between an indoor air temperature and a temperature set by a user. Controls the opening and closing of the valve. The high-temperature and high-pressure two-phase refrigerant passing through the refrigerant pipe branched from between the first indoor heat exchanger and the refrigerant sucked into the compressor are heat-exchanged and circulated, and then the original main pressure is obtained as the high-pressure liquid refrigerant. By returning to the refrigerant pipe of the refrigerant flow path, the condenser temperature and the condensation capacity of the first indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, whether or not the refrigerant is circulated is determined by determining whether or not the difference between the indoor air temperature and the temperature set by the user satisfies a predetermined temperature condition. can do.

  In the air conditioner of the present invention, the compressor, the outdoor heat exchanger, the outdoor flow rate control means, the first indoor heat exchanger, the dehumidification flow rate control means, and the second indoor heat exchanger are sequentially connected by refrigerant piping. A refrigerant that is configured to circulate a refrigerant and to exchange heat between a refrigerant pipe branched from a main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger and a refrigerant sucked into the compressor. A sub-refrigerant circuit for returning the refrigerant to the original main refrigerant flow path and a solenoid valve for controlling the refrigerant flowing into the sub-refrigerant circuit, one of the first and second indoor heat exchangers being a condenser In the air conditioner that enables reheat dehumidification operation in which the other is operated as an evaporator, the opening and closing control of the solenoid valve is performed according to the difference between the indoor air temperature and the temperature of the first indoor heat exchanger Branching between the outdoor heat exchanger and the first indoor heat exchanger The high-temperature and high-pressure two-phase refrigerant passing through the refrigerant pipe and the refrigerant sucked into the compressor are heat-exchanged and returned to the refrigerant pipe of the original main refrigerant flow path as high-pressure liquid refrigerant. The condenser temperature and the condensation capacity of the first indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, whether or not the refrigerant is circulated is determined by determining whether or not the difference between the indoor air temperature and the first indoor heat exchanger satisfies a predetermined temperature condition. It can be a refrigeration cycle.

In the air conditioner of the present invention, the compressor, the outdoor heat exchanger, the outdoor flow rate control means, the first indoor heat exchanger, the dehumidification flow rate control means, and the second indoor heat exchanger are sequentially connected by refrigerant piping. A refrigerant that is configured to circulate a refrigerant and to exchange heat between a refrigerant pipe branched from a main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger and a refrigerant sucked into the compressor. A sub-refrigerant circuit for returning the refrigerant to the original main refrigerant flow path and a solenoid valve for controlling the refrigerant flowing into the sub-refrigerant circuit, one of the first and second indoor heat exchangers being a condenser In the air conditioner that enables the reheat dehumidifying operation in which the other is operated as an evaporator, the opening / closing control of the solenoid valve is performed according to the difference between the temperature of the outdoor heat exchanger and the temperature of the first indoor heat exchanger Between the outdoor heat exchanger and the first indoor heat exchanger. The high-temperature and high-pressure two-phase refrigerant passing through the branched refrigerant pipe and the refrigerant sucked into the compressor are heat-exchanged and circulated, and then returned to the refrigerant pipe of the original main refrigerant flow path as a high-pressure liquid refrigerant. As a result, the condenser temperature and the condensation capacity of the first indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, it is determined whether or not the refrigerant is circulated by determining whether or not the difference between the temperature of the outdoor heat exchanger and the temperature of the first indoor heat exchanger satisfies a predetermined temperature condition. An optimum refrigeration cycle can be obtained.

  The air conditioner of the present invention can perform optimum refrigeration cycle control without impairing reliability.

  The first invention comprises a compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger, which are sequentially connected by a refrigerant pipe, Refrigeration cycle to be circulated, refrigerant piping branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger, and the refrigerant sucked into the compressor were heat-exchanged to circulate the refrigerant A sub-refrigerant circuit for returning to the main refrigerant flow path after the original and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, one of the first and second indoor heat exchangers being a condenser and the other being evaporated In an air conditioner that enables reheat dehumidification operation to be operated as an air conditioner, the open / close control of the solenoid valve is performed according to a difference between an indoor air temperature and a temperature set by a user. Refrigerant distribution branched from between the exchanger and the first indoor heat exchanger The high-temperature and high-pressure two-phase refrigerant passing through the refrigerant and the refrigerant sucked into the compressor are subjected to heat exchange, circulated, and then returned to the refrigerant pipe of the original main refrigerant flow path as the high-pressure liquid refrigerant. The condenser temperature and condensing capacity of one indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, whether or not the refrigerant is circulated is determined by determining whether or not the difference between the indoor air temperature and the temperature set by the user satisfies a predetermined temperature condition. can do.

  The second invention comprises a compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger, which are sequentially connected by a refrigerant pipe. Refrigeration cycle to be circulated, refrigerant piping branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger, and the refrigerant sucked into the compressor were heat-exchanged to circulate the refrigerant A sub-refrigerant circuit for returning to the main refrigerant flow path after the original and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, one of the first and second indoor heat exchangers being a condenser and the other being evaporated In the air conditioner that enables reheat dehumidification operation to be operated as an oven, the open / close control of the solenoid valve is performed according to the difference between the indoor air temperature and the temperature of the first indoor heat exchanger. A refrigerant pipe branched from between the heat exchanger and the first indoor heat exchanger The first high-temperature and high-pressure two-phase refrigerant and the refrigerant sucked into the compressor are heat-exchanged and circulated, and then returned to the refrigerant pipe of the original main refrigerant flow path as the high-pressure liquid refrigerant. The condenser temperature and condensation capacity of the indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, whether or not the refrigerant is circulated is determined by determining whether or not the difference between the indoor air temperature and the first indoor heat exchanger satisfies a predetermined temperature condition. It can be a refrigeration cycle.

According to a third aspect of the present invention, a compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger are sequentially connected by a refrigerant pipe, and the refrigerant is Refrigeration cycle to be circulated, refrigerant piping branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger, and the refrigerant sucked into the compressor were heat-exchanged to circulate the refrigerant A sub-refrigerant circuit for returning to the main refrigerant flow path after the original and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, one of the first and second indoor heat exchangers being a condenser and the other being evaporated In an air conditioner that enables a reheat dehumidifying operation to be operated as a heater, the solenoid valve is controlled to open and close according to the difference between the temperature of the outdoor heat exchanger and the temperature of the first indoor heat exchanger. A cold branching from between the outdoor heat exchanger and the first indoor heat exchanger. After exchanging heat and circulating the high-temperature and high-pressure two-phase refrigerant passing through the pipe and the refrigerant sucked into the compressor, the high-pressure liquid refrigerant is returned to the refrigerant pipe of the original main refrigerant flow path, thereby The condenser temperature and the condensation capacity of the first indoor heat exchanger can be lowered. In addition, since the second indoor heat exchanger maintains a constant evaporating temperature and dehumidifying capacity depending on the operating frequency of the compressor, only the sensible heat capacity (room temperature lowering capacity) of the indoor unit can be raised. At this time, it is determined whether or not the refrigerant is circulated by determining whether or not the difference between the temperature of the outdoor heat exchanger and the temperature of the first indoor heat exchanger satisfies a predetermined temperature condition. An optimum refrigeration cycle can be obtained.

  In the fourth aspect of the invention, the electromagnetic valve according to any one of the first to third aspects of the invention is arranged on the refrigerant pipe of the sub refrigerant circuit, and an optimum refrigeration cycle can be obtained.

  In the fifth aspect of the invention, in particular, the electromagnetic valve according to any one of the first to third aspects is arranged on the refrigerant pipe of the main refrigerant flow path, and an optimum refrigeration cycle can be obtained.

  In the sixth invention, in particular, the sub refrigerant circuit according to any one of the first to fifth inventions is branched from between the outdoor flow rate control means and the outdoor heat exchanger, and an optimum refrigeration cycle can be obtained. it can.

  In the seventh invention, in particular, the sub refrigerant circuit according to any one of the first to fifth inventions is branched from between the outdoor flow rate control means and the first indoor heat exchanger, and an optimum refrigeration cycle is obtained. be able to.

  In the eighth aspect of the invention, in particular, when the temperature of the first indoor heat exchanger or the second indoor heat exchanger of any one of the first to seventh aspects of the invention is decreased by a predetermined temperature or more in a predetermined time, the electromagnetic valve is Fully closed or fully open to stop heat exchange by the refrigerant, and can prevent freezing of the indoor heat exchanger operating as an evaporator and protect the compressor.

  In the ninth invention, in particular, when the temperature of the second indoor heat exchanger according to any one of the first to seventh inventions falls below a predetermined temperature, the electromagnetic valve is fully closed or fully opened, and heat exchange by the refrigerant is performed. The indoor heat exchanger that operates as an evaporator can be prevented from freezing and the compressor can be protected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram of the air conditioner according to the first embodiment of the present invention, and FIG. 2 is a block diagram showing a control mechanism of the air conditioner.

  The configuration and operating principle of the refrigeration cycle of the air conditioner in the present embodiment will be described with reference to FIG.

  32 is an outdoor unit, 33 is an indoor unit, 11 is a compressor, 12 is a four-way valve, 13 is an outdoor heat exchanger, 34 is an outdoor fan, 14 is an expansion valve that is an outdoor flow rate control means, and 15 is a first indoor unit. A heat exchanger, 16 is a capillary tube as a dehumidifying flow control means, 18 is a second indoor heat exchanger, and 17 is an electromagnetic on-off valve provided in parallel with the capillary tube 16. 22, 23, and 24 are temperature sensors that detect the temperatures of the first indoor heat exchanger 15, the second indoor heat exchanger 18, and the outdoor heat exchanger 13, respectively. Reference numeral 25 denotes a temperature sensor that detects the temperature of indoor air sucked into the indoor unit 33.

Between the outdoor heat exchanger 13 and the expansion valve 14, there is provided a branching portion 26 into which the refrigerant pipe 25 branches. There are an electromagnetic two-way valve 19 that is an electromagnetic valve, a capillary tube 31, a liquid-gas. A heat exchanger 21 and a sub refrigerant circuit 28 including a check valve 20 are connected.

  Hereinafter, the operation | movement at the time of the reheat dehumidification operation | movement of the air conditioner in Embodiment 1 of this invention is demonstrated.

  First, as shown by the solid line in FIG. 1, the four-way valve 12 is connected in the same manner as in the cooling operation, the expansion valve 14 is fully opened, and the electromagnetic switching valve 17 in the indoor unit 33 is closed. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 enters the outdoor heat exchanger 13 through the four-way valve 12, is radiated by the outdoor blower 34, and changes to a gas-liquid two-phase refrigerant. Thereafter, from the branch portion 26 provided before the expansion valve 14 through the refrigerant pipe 25, the main refrigerant flow path is divided, the refrigerant pipe 25 is passed, the open electromagnetic two-way valve 19 is passed, and the compressor 11 After entering the liquid-gas heat exchanger 21 provided in the suction portion, exchanging heat with the low-temperature and low-pressure suction refrigerant and changing to the high-pressure liquid refrigerant, it passes through the check valve 20 to the original main refrigerant flow path. And flow to the expansion valve 14 after joining.

  Although this refrigerant passes through the expansion valve 14, during the reheat dehumidifying operation, the expansion valve 14 is fully opened, passes through the refrigerant pipe with almost no pressure drop, and is led to the first indoor heat exchanger 15. . Here, the heat is emitted to the indoor air to be condensed and liquefied, but since it has already been converted into a liquid refrigerant, the amount of heat released is greatly reduced.

  After decompression and expansion by the capillary tube 16, the second indoor heat exchanger 18 absorbs heat from the indoor air and returns to the suction port of the compressor 11 as a low-pressure gas-liquid two-phase refrigerant.

  Here, in the indoor unit 33, the air absorbed by the second indoor heat exchanger 18 and cooled and dehumidified is mixed with the air heated by the first indoor heat exchanger 15 and blown out into the room again.

  Conventionally, since heating air and cooling air are set so as to balance as sensible heat, only dehumidification could be performed without lowering the room temperature. The room temperature could not be lowered at the outside air temperature (for example, outside air temperature 35 ° C., etc.).

  However, according to the present embodiment, as described above, the refrigerant led to the first indoor heat exchanger 15 is already in a supercooled state, and the heat radiation amount is greatly reduced, and the second indoor heat exchange is also performed. Since the chamber 18 is maintained at a constant temperature by the operation frequency of the compressor 11, the sensible heat in the room is greatly increased (increase in cooling capacity) while maintaining the dehumidifying capacity (latent heat). Actually, the temperature of the first indoor heat exchanger 15 is controlled to be 1 to 2 ° C. higher than the indoor suction temperature.

  This is because if the first indoor heat exchanger 15 becomes a temperature lower than the indoor suction temperature, the supercooled liquid refrigerant may be heated again and gasified. When the refrigerant containing the gas flows into the downstream capillary tube 16, a phenomenon called “flash” is caused to cause a rapid decrease in the refrigerating capacity, so that the temperature is controlled not to be lower than the suction temperature.

  The refrigerant sucked into the suction port of the compressor 11 is in a low-pressure gas-liquid two-phase state. Basically, it is not preferable that the liquid refrigerant returns to the compressor 11 in terms of the reliability of the refrigeration cycle. Since it is necessary to control below, the operating frequency of the compressor 11 is set high (about 35 Hz), and the low pressure is lowered due to the large amount of refrigerant circulation. However, the volume of the second indoor heat exchanger 18 is only half of the normal volume, and the liquid return is unavoidable.

  As a result, conventionally, the liquid refrigerant returned to the compressor 11 has a surplus heat absorption, and is discarded in the compressor 11 and peripheral members.

  In the present embodiment, this excess liquid refrigerant is reused to lower the condensation temperature.

  When passing through the liquid-gas heat exchanger 21, the suction refrigerant exchanges heat with the high-temperature gas-liquid two-phase refrigerant and changes into a low-pressure gas refrigerant as described above. Since the compressor 11 is immediately after, there is little pressure loss by gas refrigerant conversion. Furthermore, as shown in FIG. 1, the liquid-gas heat exchanger 21 can increase the heat exchange efficiency by using a counterflow that opposes the flow of each refrigerant.

  An example of control and operation of the refrigeration cycle of the air conditioner configured as described above will be described with reference to FIG.

  In the configuration of a conventional refrigeration cycle of an air conditioner, dehumidification can be performed without lowering the room temperature, but it is difficult to lower the room temperature. For this reason, there has been a difficult problem such as the need for switching control with the cooling operation, but in this embodiment, in order to overcome this problem, the outdoor heat is generated in the outdoor unit 32 as shown in FIG. A branch portion 26 is provided between the exchanger 13 and the expansion valve 14, and whether or not the refrigerant is branched from the branch portion 26 is controlled by the electromagnetic two-way valve 19. When the electromagnetic two-way valve 19 is closed, the refrigerant does not flow through the sub refrigerant circuit 28, and a reheat dehumidification type refrigeration cycle is achieved as before.

  However, in such a conventional cycle, a dehumidifying ability can be obtained, but it is difficult to lower the room temperature. Therefore, when the electromagnetic two-way valve 19 is opened, the high-temperature and high-pressure refrigerant radiated by the outdoor heat exchanger 13 flows through the electromagnetic two-way valve 19 to the liquid-gas heat exchanger 21, where it is cooled and converted into a high-pressure liquid refrigerant. Become. Therefore, the heat radiation amount of the indoor first indoor heat exchanger 15 becomes extremely small, and the room temperature can be lowered while maintaining the dehumidifying ability. However, a method for determining when to open the electromagnetic two-way valve 19 and when to close the electromagnetic two-way valve 19 has not been clarified so far.

  Therefore, as shown in FIG. 2, a dehumidifying operation instruction (step 1) is transmitted from the remote controller (not shown) to the indoor unit 33, and the received indoor unit 33 closes the electromagnetic on-off valve 17 (step 3). . Thereafter, an operation start instruction is transmitted from the indoor unit 33 to the outdoor unit 32, the compressor 11 is operated at a predetermined frequency (for example, 30 Hz), and the outdoor blower 34 is operated at a predetermined rotational speed (300 r / min in the present invention). ) To rotate. The expansion valve 14 is also fixed at a predetermined opening (for example, 480 pls) (step 4). However, at this time, the electromagnetic two-way valve 19 is still closed.

An indoor blower (not shown) is rotated, and heat exchange is performed by the first and second indoor heat exchangers 15 and 18. The indoor intake air sucked into the indoor unit 33 is compared with the set temperature transmitted from the remote controller in advance. When the intake temperature is higher than a predetermined temperature (Δt ₁ ) (step 5), the first indoor heat exchanger 15 When the temperature of the first indoor heat exchanger 15 is higher than a predetermined temperature (Δt ₂ ) (step 6), the electromagnetic two-way valve 19 on the outdoor unit 32 side is opened (step 6). 7).

  By doing so, in the refrigeration cycle shown in FIG. 1, the high-temperature and high-pressure two-phase refrigerant radiated by the outdoor heat exchanger 13 is branched in front of the expansion valve 14, passed through the capillary tube 31, and then the liquid-gas heat exchanger At 21, heat exchange is performed with the low-temperature and low-pressure two-phase refrigerant that returns to the compressor 11, and the heat is released to return to the main refrigerant circuit as a high-temperature and high-pressure liquid refrigerant. Therefore, the amount of heat radiated by the first indoor heat exchanger 15 is reduced, sensible heat is increased, and the ability to lower the indoor temperature can be increased. In steps 5 and 6, two conditions are imposed to open the electromagnetic two-way valve 19.

  One is that the suction temperature is a certain level higher than the set temperature. If it is not necessary to lower the room temperature due to this condition, the conventional refrigeration cycle can be operated without opening the electromagnetic two-way valve 19. it can.

  In another condition, the electromagnetic two-way valve 19 is not opened when the temperature of the first indoor heat exchanger 15 of the indoor unit 33 is not sufficiently higher than the suction temperature. It can suppress that the temperature of the 1st indoor heat exchanger 15 becomes lower than suction temperature, and can suppress generation | occurrence | production of the heat absorption phenomenon (generation | occurrence | production of a flash) by this 1st indoor heat exchanger 15.

  By these two conditions, it is possible to distinguish between an unnecessary case (no sensible heat is required) and a necessary case. Of course, determination is made at any time even during operation, and the electromagnetic two-way valve 19 is opened and closed.

  The greatest advantage of this method is that switching control is easy during operation. For example, in the conventional refrigeration cycle, when switching between reheat dehumidification operation and cooling operation, the same heat exchanger is switched between the evaporator and the condenser, so moisture and odor components attached to the heat exchanger, etc. However, it was difficult to switch over and over again.

  On the other hand, in this Embodiment, since the 1st indoor heat exchanger 15 is always used as a condenser and the 2nd indoor heat exchanger 18 is always used as an evaporator, there is no such a problem. Further, since the electromagnetic two-way valve 19 is provided in the outdoor unit 32, the opening / closing sound generated when the electromagnetic two-way valve 19 is switched to open / close cannot be heard by the user in the room.

(Embodiment 2)
FIG. 3 is a block diagram showing a control mechanism of the air conditioner according to the second embodiment of the present invention. In addition, about the same part as the air conditioner in the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As already described in the first embodiment, in the configuration of the conventional refrigeration cycle, switching control of the electromagnetic two-way valve 19 is required, and a control mechanism that forms an optimum refrigeration cycle is required.

In the present embodiment, the difference between the detected temperature of the temperature sensor 24 attached to the outdoor heat exchanger 13 and the detected temperature of the temperature sensor 22 attached to the first indoor heat exchanger 15 is a predetermined value (Δt ₃ ) When exceeding, close the electromagnetic two-way valve 19. Otherwise, the electromagnetic two-way valve 19 is opened. By doing so, it is possible to suppress the heat from being excessively dissipated from the high-temperature and high-pressure refrigerant and causing the endothermic phenomenon (generation of flash) in the first indoor heat exchanger 15.

  In principle, the detected temperature of the temperature sensor 24 attached to the outdoor heat exchanger 13 indicates the high-pressure saturation temperature in this refrigeration cycle, and the detected temperature of the temperature sensor 22 attached to the first indoor heat exchanger 15 is The degree of supercooling of the refrigerant can be detected.

  In the first embodiment, the difference from the indoor suction temperature is controlled to be a predetermined value or more. However, in the present embodiment, the degree of supercooling (hereinafter referred to as subcool) is a predetermined value. To be controlled. Specifically, it is implemented to be about 3K. When the subcool is below a certain level, the endothermic phenomenon (flash generation) is suppressed. Conversely, when the subcool is not taken (in the case of gas-liquid two-phase), the electromagnetic two-way valve 19 is opened and control is performed so that the subcool can be taken. By such control, a constant subcool (about 0 to 3K) is maintained, so that the sensible heat can be kept constant.

  In the refrigeration cycle in the first and second embodiments, the electromagnetic two-way valve 19 on the outdoor unit 32 side is arranged in the sub refrigerant circuit 28. However, as shown in FIG. The same control can be performed even if it arranges or arrange | positions the branch part 26 which branches a refrigerant flow path behind the expansion valve 14, as shown in FIG.

(Embodiment 3)
FIG. 6 is a block diagram showing a control mechanism of the air conditioner according to the third embodiment of the present invention. In addition, about the same part as the air conditioner in the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The air conditioner control mechanism described in the first and second embodiments is based on the assumption that the refrigeration cycle is operated under stable conditions. However, in fact, when an air conditioner is operated, there are various fluctuation factors, and it is often necessary to protect them.

  Therefore, in the present embodiment, the object is to suppress reliability problems caused by opening and closing of the electromagnetic two-way valve 19, in particular, freezing of the second indoor heat exchanger 18 and occurrence of liquid return. is there.

  When the electromagnetic two-way valve 19 of the outdoor unit 32 opens and closes, the refrigeration cycle fluctuates greatly temporarily. In particular, it tends to fluctuate at the time of start-up or when the frequency changes greatly. In such a case, the most frequently occurring failure is freezing of the second indoor heat exchanger 18.

  Below, the freeze prevention control of the 2nd indoor heat exchanger 18 in this Embodiment is demonstrated.

  In FIG. 6, as in the description of FIG. 1, when a dehumidifying operation instruction is transmitted from the remote controller to the indoor unit 33, the dehumidifying operation is started as described in the first embodiment, and the compressor 11 The refrigerant is circulated.

  At this time, the electromagnetic two-way valve 19 is closed. The temperature detected by the temperature sensor 22 attached to the first indoor heat exchanger 15 is sampled every predetermined time (for example, about 30 seconds), and the amount of change from the immediately preceding temperature is calculated. If the amount of change is not more than a predetermined value, it is determined that the refrigeration cycle is stable, and the electromagnetic two-way valve 19 is opened (step 37). Similarly, the temperature detected by the temperature sensor 23 attached to the second indoor heat exchanger 18 is sampled every predetermined time (for example, about 30 seconds), and the amount of change from the immediately preceding temperature is calculated.

  If the amount of change is equal to or less than a predetermined value, it is determined that the refrigeration cycle is stable, and the electromagnetic two-way valve 19 is opened (step 38). If neither is established, the electromagnetic two-way valve 19 is closed even if it has been opened before that. Thereafter, the same operation is repeated. When an operation stop instruction is transmitted from the remote controller, the operation is stopped and the electromagnetic two-way valve 19 is also closed.

  As described above, according to the present embodiment, when the refrigeration cycle is unstable, the electromagnetic two-way valve 19 does not open, so the reliability of the refrigeration cycle is improved.

Further, as a simpler embodiment, as shown in FIG. 7, after the dehumidifying operation is started, the temperature detected by the temperature sensor 23 attached to the second indoor heat exchanger is a constant temperature (t ₆ ° C. ) When the following occurs (step 39), the electromagnetic two-way valve 19 may be closed to prevent the second indoor heat exchanger 18 from freezing.

  As described above, the air conditioner according to the present invention can perform refrigeration cycle switching control without impairing reliability, and can be applied to various air conditioners for home use and business use.

Refrigeration cycle diagram of the air conditioner in the first embodiment of the present invention Block diagram showing the control mechanism of the air conditioner The block diagram which shows the control mechanism of the air conditioner in the 2nd Embodiment of this invention. Refrigeration cycle diagram showing an example in which an electromagnetic two-way valve is arranged in the main refrigerant circuit in the same air conditioner In the same air conditioner, a refrigeration cycle diagram showing an example in which an electromagnetic two-way valve is arranged in a main refrigerant circuit and a sub refrigerant circuit is branched behind an expansion valve The block diagram which shows the control mechanism of the air conditioner in the 3rd Embodiment of this invention. Block diagram showing an example of a simpler control mechanism of the air conditioner Refrigeration cycle diagram of a conventional air conditioner

Explanation of symbols

11 Compressor 12 Four-way valve 13 Outdoor heat exchanger 14 Expansion valve (outdoor flow rate control means)
15 1st indoor heat exchanger 16 Capillary tube (flow rate control means for dehumidification)
17 Electromagnetic on-off valve 18 Second indoor heat exchanger 19 Electromagnetic two-way valve (solenoid valve)
20 Check valve 21 Liquid-gas heat exchanger 22, 23, 24, 25 Temperature sensor 25 Refrigerant piping 31 Capillary tube 32 Outdoor unit 33 Indoor unit

Claims (9)

A compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger, which are sequentially connected by a refrigerant pipe and configured to circulate the refrigerant; The original main refrigerant flow after circulating the refrigerant by exchanging heat between the refrigerant pipe branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger and the refrigerant sucked into the compressor A re-refrigerant circuit for returning to the passage, and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, wherein one of the first and second indoor heat exchangers is operated as a condenser and the other as an evaporator. An air conditioner capable of performing a dehumidifying operation, wherein the electromagnetic valve is controlled to open and close according to a difference between an indoor air temperature and a temperature set by a user. A compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger, which are sequentially connected by a refrigerant pipe and configured to circulate the refrigerant; The original main refrigerant flow after circulating the refrigerant by exchanging heat between the refrigerant pipe branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger and the refrigerant sucked into the compressor A re-refrigerant circuit for returning to the passage, and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, wherein one of the first and second indoor heat exchangers is operated as a condenser and the other as an evaporator. An air conditioner capable of dehumidifying operation, wherein the electromagnetic valve is controlled to open and close according to a difference between an indoor air temperature and a temperature of the first indoor heat exchanger. A compressor, an outdoor heat exchanger, an outdoor flow rate control means, a first indoor heat exchanger, a dehumidification flow rate control means, and a second indoor heat exchanger, which are sequentially connected by a refrigerant pipe and configured to circulate the refrigerant; The original main refrigerant flow after circulating the refrigerant by exchanging heat between the refrigerant pipe branched from the main refrigerant flow path between the outdoor heat exchanger and the first indoor heat exchanger and the refrigerant sucked into the compressor A re-refrigerant circuit for returning to the passage, and an electromagnetic valve for controlling the refrigerant flowing into the sub-refrigerant circuit, wherein one of the first and second indoor heat exchangers is operated as a condenser and the other as an evaporator. An air conditioner capable of dehumidifying operation, wherein the opening and closing control of the electromagnetic valve is performed according to a difference between a temperature of the outdoor heat exchanger and a temperature of the first indoor heat exchanger. . The air conditioner according to any one of claims 1 to 3, wherein the electromagnetic valve is arranged on a refrigerant pipe of the sub refrigerant circuit. The air conditioner according to any one of claims 1 to 3, wherein the electromagnetic valve is disposed on a refrigerant pipe of the main refrigerant channel. The air conditioner according to any one of claims 1 to 5, wherein the auxiliary refrigerant circuit is branched from between the outdoor flow rate control means and the outdoor heat exchanger. The air conditioner according to any one of claims 1 to 5, wherein the sub refrigerant circuit is branched from between the outdoor flow rate control means and the first indoor heat exchanger. When the temperature of a 1st indoor heat exchanger or a 2nd indoor heat exchanger falls more than predetermined temperature in predetermined time, a solenoid valve is fully closed or fully opened, and heat exchange by a refrigerant | coolant is stopped, It is characterized by the above-mentioned. Item 8. The air conditioner according to any one of Items 1 to 7. 8. The method according to claim 1, wherein when the temperature of the second indoor heat exchanger decreases to a predetermined temperature or lower, the electromagnetic valve is fully closed or fully opened, and heat exchange by the refrigerant is stopped. The air conditioner described.

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