JP2014029239A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner having high operation efficiency and ensuring excellent energy saving while maintaining dehumidification capability even at a time of partial loading.SOLUTION: An air conditioner includes: an injection circuit 5 branching off between a condenser 2 and a first expansion valve 31, and injecting a part of a refrigerant having passed through the condenser 2 into an injection port of a compressor 1 in gaseous form; a first evaporation flow path L1 connected to a suction port of the compressor 1 by way of the first expansion valve 31 and an indoor heat exchanger HE2, and having a first evaporation part 41 formed in the indoor heat exchanger HE2; and a second evaporation flow path L2 branching off between a branch point of the injection circuit 5 between the condenser 2 and the first expansion valve 31 and the first expansion valve 31, and merged with the first evaporation flow path L1 after passing through the indoor heat exchanger HE2. A second expansion valve 32 provided upstream of the indoor heat exchanger HE2 and a second evaporation part 42 formed in the indoor heat exchanger HE2 are provided on the second evaporation flow path L2.

Description

  The present invention relates to an air conditioner including a mechanism related to temperature and humidity control during partial load.

  When the air conditioner is operated without performing special control in a partial load state, the operation efficiency is deteriorated as compared with a state where the air conditioner is operated at a rated load.

  Conventionally, in order not to lower the operation efficiency even at the time of partial load, it has been performed to increase the evaporation temperature in the evaporator and achieve substantially the same operation efficiency as in the state of operation at the rated load ( Patent Document 1).

  However, if the evaporation temperature of the evaporator is simply increased, the surface temperature of the indoor heat exchanger that constitutes the evaporator at the time of cooling becomes higher than the indoor dew point temperature. Condensation will no longer occur on the surface.

  For this reason, indoor air dehumidification cannot be performed by the air conditioner and the humidity cannot be controlled, so that comfort may be impaired.

  In other words, operating efficiency can be maintained by simply changing the evaporation temperature at the time of partial load, while dehumidifying performance will be reduced, and conventional air conditioners will improve operating efficiency and comfort at partial load. It is difficult to achieve both.

JP 2005-291484 A

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide an air conditioner that has high operating efficiency and excellent energy saving performance while maintaining the dehumidifying ability even at the time of partial load. And

  That is, the air conditioner of the present invention is an air conditioner in which a compressor, a condenser constituted by an outdoor heat exchanger, a first expansion valve, and an evaporator constituted by an indoor heat exchanger are connected in a ring shape. An injection circuit for branching between the condenser and the first expansion valve and allowing a part of the refrigerant that has passed through the condenser to flow into the injection port of the compressor in a gaseous state; and the first expansion A valve is connected to the suction port of the compressor through the indoor heat exchanger, and a first evaporation channel in which a first evaporation section is formed in the indoor heat exchanger, the condenser, and the first A second evaporation channel that branches from the branch point of the injection circuit between the first expansion valve and the first expansion valve, and merges with the first evaporation channel after passing through the indoor heat exchanger And comprising the second steam Flow path, characterized in that it comprises a second expansion valve disposed upstream of the indoor heat exchanger, and a second evaporator section which is formed in the indoor heat exchanger.

  In this case, since the second evaporation channel provided in parallel with the first evaporation channel is provided, the evaporation temperatures of the first evaporation unit and the second evaporation unit are respectively set. Any temperature can be set separately.

  Therefore, for example, the evaporation temperature of the first evaporation unit is set to be close to the dew point temperature in the room to ensure dehumidification performance, and the evaporation temperature of the second evaporation unit is set to the first evaporation at the time of partial load. It is possible to increase the operation efficiency by operating at a capacity that is higher than the section and according to the partial load.

  Further, in the present invention, since the injection circuit is provided upstream of the first evaporation channel and the second evaporation channel, the refrigerant flowing into each evaporation channel is a liquid having a high ratio of liquid refrigerant at intermediate pressure. A rich state can be obtained. Accordingly, since the refrigerant is easily branched into the first evaporation channel and the second evaporation channel, the evaporation temperatures in the first evaporation unit and the second evaporation unit can be easily controlled to arbitrary temperatures, respectively. .

  Further, by using the injection circuit, it is possible to control the room temperature without reducing the cycle efficiency even at the time of partial load.

  In order to make it easier to control the evaporation temperature of the second evaporation part of the second evaporation channel and to keep the operation efficiency at the time of partial load high, the second evaporation channel is more than the summer heat exchanger. May also include a third expansion valve provided downstream.

  In order to maintain a high operating efficiency while maintaining dehumidification performance at the time of partial load, it is only necessary that the evaporation temperature in the second evaporation section is set higher than the evaporation temperature in the first evaporation section at the time of partial load operation. . If it is such, dehumidification is possible in the 1st evaporation part, and in the 2nd evaporation part, cooling capacity can be reduced according to partial load, and operation efficiency can be approximated at the time of rated operation.

  As a control mode for maintaining a state in which both comfort and driving efficiency are achieved at the time of partial load, the evaporation temperature in the second evaporation section is higher than a reference dew point temperature corresponding to a predetermined reference relative humidity. In such a case, at least the opening degree of the first expansion valve or the second expansion valve may be changed so that the evaporation temperature in the first evaporation unit becomes lower than the reference dew point temperature.

  As an injection circuit for supplying a liquid-rich refrigerant to the first evaporation channel and the second evaporation channel to facilitate setting the evaporation temperature in each evaporation unit to a desired temperature, the injection circuit is: A fourth expansion valve and a gas-liquid separator that separates the refrigerant that has passed through the condenser into a gas and a liquid; the gaseous refrigerant separated by the gas-liquid separator flows into the injection port; The refrigerant is configured to flow into the first evaporation channel and the second evaporation channel.

  In another embodiment of the injection circuit, the injection circuit exchanges heat between the fourth expansion valve, the refrigerant that has passed through the fourth expansion valve, and the refrigerant that flows from the condenser to the evaporator. And an intermediate heat exchanger for performing the above.

  As described above, according to the air conditioner of the present invention, the evaporation temperature is set low in a part of the evaporator to ensure the dehumidification capacity, while the evaporation temperature is set high in the other part according to the partial load. As a capability, the operation efficiency can be brought close to the same as that during rated operation. Therefore, it is possible to provide an air conditioner that achieves both comfort and driving efficiency even during partial loads. Further, by using the injection circuit, not only the operation efficiency can be improved, but also a liquid-rich refrigerant can be supplied, so that the refrigerant can be suitably branched to each evaporation channel, and in each evaporation section The evaporation temperature can be set arbitrarily.

The typical circuit diagram of the air harmony device concerning a 1st embodiment of the present invention. The ph diagram of the air harmony device in a 1st embodiment. The typical circuit diagram of the air harmony device concerning a 2nd embodiment of the present invention. The ph diagram of the air harmony device in a 2nd embodiment.

  A first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, an air conditioner 100 according to the first embodiment includes a compressor 1, a condenser 2 constituted by an outdoor heat exchanger HE 1, a first expansion valve 31, and an evaporation constituted by an indoor heat exchanger HE 2. The vessel 4 includes a main refrigerant circuit connected in an annular shape.

  Furthermore, the air conditioner 100 of the first embodiment is formed in parallel with the main refrigerant circuit on the evaporator 4 side and the injection circuit 5 that supplies the medium pressure refrigerant from the high pressure side in the main refrigerant circuit to the compressor 1. Further, a 2 evaporation channel L2 is added.

  That is, the evaporator 4 side of the air conditioner 100 is connected from the first expansion valve 31 to the suction port of the compressor 1 through the indoor heat exchanger HE2, and the indoor heat exchanger HE2 is connected. The first evaporation channel L1 in which the first evaporation part 41 is formed, the branch point of the injection circuit 5 between the condenser 2 and the first expansion valve 31, and the first expansion valve 31 And a second evaporation channel L2 that branches from the interior and passes through the indoor heat exchanger HE2 and merges with the first evaporation channel L1. Thus, since the evaporator 4 of 1st Embodiment is made so that two evaporation flow paths may flow in in one indoor heat exchanger HE2, evaporation temperature can be varied according to a part. The operation of the compressor 1 and each expansion valve is controlled by a control mechanism (not shown).

  Each part will be described.

  The compressor 1 includes a suction port through which low-pressure refrigerant is sucked, a discharge port through which refrigerant compressed to high pressure is discharged, and an injection port through which intermediate-pressure gas refrigerant is sucked from the injection circuit 5. It is a multistage compressor. More specifically, the compressor 1 first compresses the refrigerant sucked from the suction port in the low-stage compression section, and connects the intermediate-pressure refrigerant compressed in the low-stage compression section with the injection port from the injection circuit 5. And a high-stage compression unit that mixes and compresses the gas refrigerant with an intermediate pressure introduced through the discharge port and discharges it from the discharge port.

  The condenser 2 is constituted by an indoor heat exchanger HE2 formed such that a condensing coil formed by a single refrigerant pipe meanders in the radiating fin.

  The injection circuit 5 branches between the condenser 2 and the first expansion valve 31 and allows a part of the refrigerant that has passed through the condenser 2 to flow into the injection port of the compressor 1 in a gaseous state. Is.

  More specifically, the injection circuit 5 includes a gas-liquid separator 51 that separates the refrigerant that has passed through the condenser 2 provided between the condenser 2 and the first expansion valve 31 into gas and liquid. The gas refrigerant separated by the gas-liquid separator 51 flows into the injection port, and the liquid refrigerant flows into the first evaporation channel L1 and the second evaporation channel L2. It is constituted as follows.

  The evaporator 4 includes an indoor heat exchanger HE2 formed such that two evaporation coils formed by respective refrigerant pipes of the first evaporation channel L1 and the second evaporation channel L2 meander in the radiation fins in parallel. It is comprised by.

  The first evaporation flow path L1 includes, in order from the upstream side, the first expansion valve 31 and a first evaporation part 41 in which heat exchange is performed between the indoor air by an evaporation coil in the indoor heat exchanger HE2. It is equipped with. The evaporation temperature of the first evaporator 41 is controlled so as to be a relatively low evaporation temperature both during rated load operation and during partial load operation. That is, in the first evaporator 41, the control mechanism controls the opening degree of the first expansion valve 31 so as to maintain a state in which condensation from indoor air is likely to occur in any operating state. It is configured.

  The second evaporation flow path L2 includes, in order from the upstream, the second expansion valve 32, the second evaporator 42 in which heat is exchanged between the indoor air by the evaporation coil of the indoor heat exchanger HE2, and the second 3 expansion valve 33 is provided. The second expansion valve 32 and the third expansion valve 33 are opened so that the evaporation temperature of the second evaporator 42 is maintained at an evaporation temperature higher than the evaporation temperature of the first evaporator 41 during partial load operation. The degree is controlled by the control mechanism.

  The control mechanism is configured such that when the evaporation temperature in the second evaporator 42 is higher than a reference dew point temperature corresponding to a predetermined reference relative humidity, the evaporation temperature in the first evaporator 41 is a reference dew point. The opening degree of each expansion valve is changed so as to be lower than the temperature.

  More specifically, a temperature / humidity region in which the room temperature is 18 to 27 ° C. and the relative humidity is 40 to 65% is recognized as a comfortable space. When the cooling operation is performed in such a temperature and humidity region, the partial load operation is brought into a state. In such a temperature / humidity region, the control mechanism controls the opening degrees of the second expansion valve 32 and the third expansion valve 33 so that the evaporation temperature of the second evaporator 42 is higher than that in the normal operation. When the partial load is very small, the control mechanism may set the evaporation temperature (evaporation pressure) of the first evaporator 41 higher than during normal rated operation. Even in this case, the evaporating temperature of the first evaporating unit 41 is set to a temperature lower than the evaporating temperature of the second evaporating unit 42, and condensation is generated from the indoor air, so that the dehumidifying function is completely lost. Control to prevent

  More specifically, when the evaporation temperature of the second evaporator 42 reaches a dew point temperature corresponding to 60% that is a reference relative humidity, the control mechanism determines that the evaporation temperature of the first evaporator 41 is The opening degree of each expansion valve is controlled so as to be lower than the dew point temperature corresponding to 60% which is the reference relative humidity. That is, since the evaporation temperature in the first evaporation part 41 can be substantially regarded as the surface temperature of the radiating fin, at least in the first evaporation part 41, condensation can be caused from room air, and the first With respect to the two evaporators 42, the operation efficiency can be maintained substantially equal to that during the rated operation by increasing the evaporation temperature according to the state of the partial load.

  Next, operation | movement of the air conditioning apparatus 100 of 1st Embodiment comprised in this way is demonstrated, referring the ph diagram of FIG. In addition, the alphabet attached | subjected to each point of FIG. 1 respond | corresponds to the alphabet attached | subjected to each point of FIG. 2, respectively. That is, a cycle indicated by A, G, B, C, D, E, I, A indicates a normal refrigeration cycle, D, F, H indicate changes in the state of the refrigerant by the injection circuit 5, and E, I ′ , A ′ indicates the change in the state of the refrigerant through the second evaporation channel L2.

  The low-stage compressor of the compressor 1 sucks low-pressure refrigerant flowing from the first evaporation flow path L1 indicated by A in FIG. 2 and medium-low pressure refrigerant indicated by A ′ in FIG. Compress to G point.

  The high-stage compressor of the compressor 1 sucks the intermediate-pressure refrigerant compressed to the point G in the low-stage compressor and the intermediate-pressure refrigerant supplied from the injection circuit 5 from the injection port, and is indicated by B Compress to high pressure.

  With respect to the refrigerant changed from the point B to the point C by the condenser 2, the gas-liquid separator 51 constituting the injection circuit 5 performs gas-liquid separation. Accordingly, the state of the gas refrigerant generated by the injection circuit 5 changes along the routes D, F, and H. On the other hand, the liquid refrigerant generated by the injection circuit 5 immediately before flowing into the first evaporation flow path L1 and the second evaporation flow path L2 is liquid rich occupied in a substantially liquid state as indicated by point E. It is in the state of.

  Therefore, it is easy to branch the refrigerant at a desired flow rate with respect to each of the first evaporation channel L1 and the second evaporation channel L2. That is, it is easy to set the evaporation temperature (evaporation pressure) of each of the first evaporator 41 and the second evaporator 42 to an arbitrary value.

  The refrigerant passing through the first evaporating flow path L1 changes in the state of E, I, and A, and its evaporating temperature (evaporating pressure) is maintained at a temperature lower than the dew point temperature in the room. Therefore, in the evaporation coil formed by the first evaporation channel L1, the dehumidifying performance can be ensured at any time during rated operation or partial load operation.

  On the other hand, the refrigerant passing through the second evaporation flow path L2 changes in the state of E, I ′, A ′, and the evaporation temperature (evaporation temperature) is evaporated in the first evaporation flow path L1 at the partial load. The temperature is set higher than the temperature by a predetermined temperature. Therefore, in the evaporation coil formed by the second evaporation flow path L2, the evaporation temperature becomes high during partial load operation, and thus the dehumidification capability may be lost, but the operation efficiency during rated operation and partial load operation is substantially reduced. Can be the same.

  As described above, in the air conditioner 100 of the present invention, when the entire evaporator 4 is considered, it is possible to ensure the dehumidifying capacity even during partial load operation, to maintain comfort, and to achieve both energy savings. be able to.

  In other words, the entire evaporator 4 has the injection circuit 5 and the evaporator 4 is divided into the first evaporation channel L1 and the second evaporation channel L2. However, the evaporation temperature can be varied for each portion of the evaporator 4. Accordingly, it is possible to always set the dehumidifying capacity in a part of the evaporator 4 while setting the evaporation temperature to maintain the operation efficiency in the other part.

  Next, the air conditioning apparatus 100 of 2nd Embodiment is demonstrated. In addition, the same code | symbol shall be attached | subjected to the member corresponding to 1st Embodiment.

  As shown in FIG. 3, the air conditioner 100 of the second embodiment differs from the first embodiment in the configuration of the injection circuit 5, but the evaporation temperatures in the first evaporator 41 and the second evaporator 42. This setting is the same as in the first embodiment, and the same applies to the control of each expansion valve and the like.

  More specifically, the injection circuit 5 in the second embodiment includes a fourth expansion valve 34, a refrigerant that has passed through the fourth expansion valve 34, and a refrigerant that flows from the condenser 2 to the evaporator 4. And an intermediate heat exchanger 52 that performs heat exchange between them.

  Because of such a configuration, the refrigerant flowing into the first evaporation channel L1 and the second evaporation channel L2 is different in the state at point E as shown in the ph diagram of FIG. Can be made rich in liquid, and the refrigerant can be easily branched. Therefore, it is possible to set the evaporation temperature at the first evaporator 41 and the second evaporator 42 to an arbitrary value as in the first embodiment.

  That is, even in the air conditioner 100 as in the second embodiment, the comfort is maintained while ensuring the dehumidifying capacity during the partial load operation as in the air conditioner 100 of the first embodiment, and the operation efficiency is improved. Can be maintained at the same level as during rated operation.

  Other embodiments will be described.

  The injection circuit is not limited to that shown in each embodiment, and various modifications may be used. In short, any material can be used as long as it can easily divide the refrigerant into the respective evaporation channels and can generate a liquid-rich refrigerant.

  The evaporating temperature in the first evaporating unit and the second evaporating unit may be set according to the partial load state and the indoor relative humidity.

  In addition, various modifications and combinations of embodiments may be performed without departing from the spirit of the present invention.

100: Air conditioner 1: Compressor 2: Condenser 4: Evaporator 5: Injection circuit 31: First expansion valve 32: Second expansion valve 33: Third expansion valve 34: Fourth expansion valve 41: First evaporation Unit 42: second evaporator 51: gas-liquid separator 52: intermediate heat exchanger HE1: outdoor heat exchanger HE2: indoor heat exchanger L1: first evaporation channel L2: second evaporation channel

Claims (6)

A compressor, a condenser constituted by an outdoor heat exchanger, a first expansion valve, and an evaporator constituted by an indoor heat exchanger are annularly connected to an air conditioner,
An injection circuit that branches between the condenser and the first expansion valve, and causes a part of the refrigerant that has passed through the condenser to flow into the injection port of the compressor in a gaseous state;
A first evaporation channel connected from the first expansion valve through the indoor heat exchanger to the suction port of the compressor, and forming a first evaporation section in the indoor heat exchanger;
A branch point of the injection circuit between the condenser and the first expansion valve branches from between the first expansion valve and passes through the indoor heat exchanger, and then merges with the first evaporation channel. A second evaporation channel
The second evaporation flow path includes a second expansion valve provided upstream of the indoor heat exchanger, and a second evaporator formed in the indoor heat exchanger. Harmony device.   The air conditioning apparatus according to claim 1, wherein the second evaporation channel includes a third expansion valve provided downstream of the summer heat exchanger.   The air conditioning apparatus according to claim 1 or 2, wherein an evaporation temperature in the second evaporator is set higher than an evaporation temperature in the first evaporator during partial load operation.   When the evaporation temperature in the second evaporation unit is higher than a reference dew point temperature corresponding to a predetermined reference relative humidity, the evaporation temperature in the first evaporation unit is lower than the reference dew point temperature. The air conditioner according to any one of claims 1 to 3, wherein at least an opening degree of the first expansion valve or the second expansion valve is changed.   The injection circuit includes a fourth expansion valve and a gas-liquid separator that separates the refrigerant that has passed through the condenser into a gas and a liquid, and the gaseous refrigerant separated by the gas-liquid separator is supplied to the injection port. The air conditioner according to any one of claims 1 to 4, wherein the air conditioner is configured to flow in and the liquid refrigerant flows into the first evaporation channel and the second evaporation channel. The injection circuit includes a fourth expansion valve, an intermediate heat exchanger that exchanges heat between the refrigerant that has passed through the fourth expansion valve and the refrigerant that flows from the condenser to the evaporator. The air conditioner according to any one of claims 1 to 4.