JP2007127333A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dew condensation in a cross flow fan and a casing during cooling operation, and to suppress dew condensation while preventing breakage of a compressor during cooling operation when using a heat exchanger with a reduced amount of materials of an indoor unit in an air conditioner. <P>SOLUTION: The amount of used materials is reduced by providing one row of heat transfer tubes with respect to a flowing direction of air of an indoor heat exchanger, and dew condensation due to inflow of air that has not been cooled or dehumidified into the cross flow fan is suppressed by providing a means for heating a refrigerant between one row of heat exchangers and a compressor suction part during cooling operation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner including an indoor unit including an indoor heat exchanger and a cross-flow fan.

  2. Description of the Related Art Conventionally, an indoor unit used in an air conditioner has a structure disclosed in Patent Document 1, for example. In the heat exchanger of the indoor unit described in Patent Document 1, the upper front heat exchanger and the upper rear heat exchanger are arranged in an inverted V shape, and the lower front heat exchanger is disposed below the upper front heat exchanger. An indoor heat exchanger configured as an exchanger and an auxiliary heat exchanger (subcooler) arranged on the windward side of the upper rear heat exchanger are provided. A cross-flow fan is provided leeward of the indoor heat exchanger. And this indoor heat exchanger becomes two rows in which the number of rows of heat exchanger tubes with respect to the air flow direction is a plurality of rows.

JP 2002-81672 A (FIG. 6)

  Since the indoor heat exchanger provided in the indoor unit of the air conditioner described in Patent Document 1 is composed of a plurality of rows of heat transfer tubes with respect to the air flow direction, it is generally made of a copper material. Many heat transfer tubes are needed. Copper is a finite resource on the earth, and there was a problem of a decrease in copper resources. Moreover, since the space volume in the heat transfer tube is large, a large amount of refrigerant to be sealed is necessary. Current air conditioners generally use refrigerants R410A, R407C, and R22, but they all have global warming potential, so if refrigerant leaks into the atmosphere when moving or disposing of air conditioners, the global environment will be affected. There are concerns about giving.

  If the air conditioner with reduced material is used for the above purpose, there is a problem that condensed water flows out from the air outlet of the indoor unit.

  The first object of the present invention is to provide an air conditioner that reduces the global environmental load.

  A second object of the present invention is to provide an air conditioner that suppresses the flow of condensed water from the air outlet of an indoor unit when the air conditioner has a reduced material.

  The first object is to provide an air conditioner having an indoor unit having an indoor heat exchanger and a cross-flow fan, wherein the number of rows of heat transfer tubes in the air flow direction of the indoor heat exchanger is one. This is achieved by using a machine.

  The second object is an air conditioner including an indoor unit having an indoor heat exchanger and a cross-flow fan, wherein the number of rows of heat transfer tubes with respect to the air flow direction of the indoor heat exchanger is one, and cooling operation is performed. This is sometimes achieved by providing an air conditioner equipped with refrigerant overheating means for heating the refrigerant between the indoor heat exchanger and the compressor suction section.

  ADVANTAGE OF THE INVENTION According to this invention, the air conditioner which reduces a global environmental load can be provided.

  Moreover, when it is set as the air conditioner which reduced material, the air conditioner which suppressed that dew condensation water flows out from the air blower outlet of an indoor unit can be provided.

  An embodiment of the present invention will be described with reference to FIG. A cross-flow fan 2 and an indoor heat exchanger 3 are provided in the indoor unit 1 of the air conditioner. The indoor heat exchanger 3 includes an upper front heat exchanger portion 3a, an upper rear heat exchanger portion 3b, and a lower front heat exchanger portion 3c provided below the upper front heat exchanger portion 3a. The upper front heat exchanger portion 3a and the upper rear heat exchanger portion 3b have a vertical V-shaped cross section. The indoor heat exchanger 3 is composed of a heat transfer tube 5 through which refrigerant flows and an aluminum fin 4, and a cross fin tube type that is inserted so as to be orthogonal to the laminated fin 4 is adopted. Has been. A front dew tray 20 that receives moisture in the air condensed in the upper front heat exchanger portion 3a and the lower front heat exchanger portion 3c is disposed below the lower front heat exchanger portion 3c. Further, a backside dew tray 21 for receiving moisture condensed in the heat exchanger part is provided at the lower part of the upper rear heat exchanger part 3b.

  When the once-through fan 2 rotates, the indoor air sucked from the air suction port 22 is heat-exchanged by the indoor heat exchanger 3 and is blown out from the air blowing port 23 via the once-through fan 2.

  By the way, the indoor heat exchanger 3 makes the number of rows of the heat transfer tubes 5 with respect to the flow direction of the air performing heat exchange one row. Thus, since the number of rows of the heat transfer tubes with respect to the air flow direction of the indoor heat exchanger 3 is one row, the number of rows described in Patent Document 1 is made of a copper material as compared with the case where there are a plurality of rows. The amount of heat transfer tube 5 used can be reduced. Furthermore, since the internal volume of the heat transfer tube can be reduced, the required amount of enclosed refrigerant can be reduced as compared with the conventional case. For this reason, even if the refrigerant used has the global warming ability of R410A, R407C, and R22, even if the refrigerant leaks into the atmosphere when the air conditioner is moved or discarded, the impact on the global environment can be reduced. it can.

  In this embodiment, the shape of the indoor heat exchanger 3 is an inverted V-shaped vertical cross section of the upper front heat exchanger portion 3a and the upper rear heat exchanger portion 3b. If it is one row, the effect is the same regardless of the shape of the heat exchanger, and it may be an arc-shaped indoor heat exchanger 6 whose cross section is formed by a curve as shown in FIG.

  By the way, when the number of rows of the heat transfer tubes 5 of the indoor heat exchanger 3 is 1, the dew is attached to the cross-flow fan 2 during the cooling operation in which the indoor heat exchanger 3 acts as an evaporator, and this dew is blown out into the air. There was a problem of jumping out of the mouth 23 and scattering into the room.

  This is because when the operating load changes abruptly during cooling operation, or when the amount of pressure reduction in the pressure reducing means (expansion device) is not appropriate, such as during startup, the vicinity of the evaporator outlet (in the indoor heat exchanger 3 during cooling operation). In some cases, the refrigerant in the first to several stages of the heat transfer pipe upstream from the heat transfer pipe serving as the refrigerant outlet becomes an overheated region. The refrigerant in the superheated area is a gas refrigerant, the temperature of the heat exchanger is higher than the dew point temperature of the incoming air, and the air passing through the vicinity of the heat transfer pipe 5 through which the refrigerant in the superheated area flows is not dehumidified. Keep touching the indoor unit housing and cross-flow fan. Here, the casing and the cross-flow fan are cooled to low temperature by the air that has been cooled and dehumidified in the heat exchanger portion where the heat transfer pipe 5 in which the refrigerant flowing in the non-superheated region (gas-liquid two-phase region) flows exists. Yes. If the non-humidified air comes into contact therewith, condensation occurs there, and the condensed water drops outside the indoor unit.

  In order to avoid this problem, it is conceivable to reduce the amount of decompression by the decompression means so as to suppress overheating in the indoor heat exchanger 3 serving as an evaporator. When the amount of pressure reduction is adjusted in this way, when the operating load changes suddenly or when the amount of pressure reduction by the pressure reduction means at the time of startup or the like is not appropriate, evaporation in the evaporator (indoor heat exchanger 3) is completed. Therefore, unevaporated refrigerant flows into the compressor and liquid compression is performed by the compressor, which may damage the compressor.

  An embodiment for solving this problem will be described with reference to FIG. 3 is an indoor heat exchanger and 7 is an auxiliary heat exchanger. The auxiliary heat exchanger 7 is connected to the outlet of the evaporator, that is, to the refrigerant pipe between the indoor heat exchanger 3 and the compressor suction portion during the cooling operation in which the indoor heat exchanger 3 acts as an evaporator. Has been. Moreover, as an air path, it arrange | positions so that it may become a windward side of the indoor heat exchanger 3, ie, the indoor heat exchanger 3, and a some line. In this embodiment, it is disposed on the windward side of the upper rear heat exchanger section 3b.

  The indoor unit 1 is incorporated in a refrigeration cycle, 8 is a compressor, 9 is a four-way valve as a refrigerant flow switching device, 10 is a condenser during cooling, and an outdoor heat exchanger that functions as an evaporator during heating. , 11 is a capillary tube as decompression means, and 12 is an outdoor fan.

  An operation during the cooling operation of the air conditioner configured as described above will be described. The high-temperature and high-pressure refrigerant gas compressed by the compressor 8 passes through the four-way valve 9, dissipates heat to the air blown by the blower fan 12 in the outdoor heat exchanger 10 and condenses. Further, the pressure is reduced by the capillary tube 11 to become a low temperature and low pressure state, enters the indoor unit 1, is branched into two systems by the refrigerant branching device 24, and flows into the upper front heat exchanger section 3 a of the indoor heat exchanger 3. The refrigerant branched to one side flows through the heat transfer tubes 5 in the upper front heat exchanger section 3a in four stages and then flows into the upper rear heat exchanger section 3b. The refrigerant that has flowed out of the upper rear heat exchanger section 3 b flows into the auxiliary heat exchanger 7. The other refrigerant flows through the upper front heat exchanger section 3a through the two heat transfer tubes 5 and then flows into the lower front heat exchanger section 3c. The refrigerant that has flowed out of the lower front heat exchanger section 3 c flows into the auxiliary heat exchanger 7, joins with the previous refrigerant at the refrigerant branching device 25, reaches the outdoor unit, and is connected to the compressor via the four-way valve 9. 8 suction parts. While flowing through the indoor heat exchanger 3 and the auxiliary heat exchanger 7, the refrigerant evaporates by absorbing heat from the air blown by the once-through fan 2, and returns to the compressor 8 again as described above.

  By configuring as described above, it is possible to prevent dew attached to the cross-flow fan 2 from flowing out of the indoor unit 1. The operation will be described. When the air flow rate of the once-through fan 2 suddenly increases, when the room temperature rapidly increases, or when the amount of pressure reduction in the capillary tube 11 is excessive, the evaporation of the refrigerant is completed in the indoor heat exchanger 3, and as described above. Cause dew condensation. However, in this embodiment, the auxiliary heat exchanger 7 is provided, and even in the above extreme case, the amount of refrigerant filled in the indoor heat exchanger 3 is a saturated region, so that the inside of the indoor heat exchanger 3 Can be prevented from overheating. In this way, the air downstream side of the auxiliary heat exchanger 7 can be the indoor heat exchanger 3 in which the refrigerant is not in the overheating region, so that the passing air is cooled and dehumidified on the entire surface of the indoor heat exchanger 3. Become. For this reason, it is possible to prevent the occurrence of dew condensation in the cross-flow fan or the casing due to insufficient dehumidification of some air.

  In the above embodiment, the auxiliary heat exchanger 7 is provided downstream of the indoor heat exchanger 3 in the refrigerant flow during the cooling operation in order to set the state of the refrigerant inside the heat transfer tube of the indoor heat exchanger 3 to the saturation region. The refrigerant in the saturation region was made the superheated region by the auxiliary heat exchanger 7. An embodiment in which the refrigerant in the indoor heat exchanger 3 is saturated without using the auxiliary heat exchanger 7 will be described with reference to FIG.

  As shown in FIG. 4, the auxiliary heat exchanger 7 is not provided in the indoor unit 1 in this embodiment. Instead, an electric heater 13 as a refrigerant overheating means is provided in the refrigerant pipe between the refrigerant outlet of the indoor heat exchanger 3 and the compressor suction portion during the cooling operation.

  With the configuration described above, even if the refrigerant cannot complete evaporation in the indoor heat exchanger 3 during the cooling operation, the heat is absorbed from the electric heater 13 after exiting the indoor heat exchanger 3 to complete evaporation. For this reason, since the non-evaporated refrigerant does not flow into the compressor 8, liquid compression is not caused in the compressor, and damage to the compressor can be prevented. At this time, the indoor heat exchanger 3 does not have an overheating region that is higher than the dew point temperature of the inflowing air, so that no dew condensation occurs in the cross-flow fan or the housing as in the effect of the above-described embodiment.

  In this embodiment, if the refrigerant superheat amount detection means (not shown) is provided after being overheated by the electric heater and the electric input amount of the electric heater is controlled so as not to become an excessive amount of overheat, the electric heater An increase in power consumption due to input can be prevented.

  In the present embodiment, the case where an electric heater is used as the means for heating the non-evaporated refrigerant has been described. However, as shown in FIG. 5, the refrigerant pipe between the indoor heat exchanger 3 and the compressor 8 is connected to the compressor chamber and the heat. May be used as a heat exchanger 14 using the residual heat of the compressor, and may be overheated by the residual heat from the compressor 8. In this case, since the compressor is cooled by the evaporating temperature, that is, the low-temperature refrigerant, the motor efficiency in the compressor can be improved, and the reduction in the compression efficiency due to the thermal deformation due to the temperature rise can be reduced. Can also be achieved.

  Further, since the refrigerant in the compressor suction portion can be overheated by the compressor residual heat use heat exchanger 14 as the refrigerant overheating means, the capillary tube 11 is set so that the evaporator 3 is not overheated, or the pressure reducing means As an alternative, an electric expansion valve 24 of variable pressure reduction type may be used instead of a capillary tube, and this may be controlled so that the evaporator 3 does not become an overheating region. In this case, since the entire surface of the indoor heat exchanger 3 is in a two-phase region where the temperature is not high, it is possible to suppress the occurrence of dew condensation in the cross-flow fan and the housing as in the effect of the previous embodiment.

  In the above embodiment, the auxiliary heat exchanger 7, the electric heater 13, or the compressor residual heat utilization heat exchanger 14 is used as the superheating means. However, another embodiment that does not use these will be described with reference to FIG. In this embodiment, a refrigerant heating heat exchanger 15 and a check valve 16 are provided. That is, a high-pressure side heat exchanger 15 a that is high in the cooling operation of the check valve 16 and the refrigerant heating heat exchanger 15 is provided in parallel with the refrigerant pipe between the outdoor heat exchanger 10 and the capillary tube 11. A low-pressure-side heat exchanger 15b that has a low pressure during the cooling operation is provided in the pipe between the exchanger 3 and the four-way valve 9. The high-pressure side heat exchanger 15a and the low-pressure side heat exchanger 15b constitute the refrigerant heating heat exchanger 15, and heat exchange between the refrigerants is performed between them.

  The refrigerant heating heat exchanger 15 and the check valve 16 heat the refrigerant between the indoor heat exchanger 3 and the compressor 8 and the refrigerant between the outdoor heat exchanger 10 and the capillary tube 11 only during the cooling operation. Connected to replace. During the heating operation, the refrigerant does not flow through the bypass flow path due to the action of the check valve 16.

  By configuring as described above, even if the refrigerant cannot complete evaporation in the indoor heat exchanger 3 during the cooling operation, it functions as a condenser in the refrigerant heating heat exchanger 15 after leaving the indoor heat exchanger 3. It absorbs the heat of the refrigerant in the supercooling region that has come out of the outdoor heat exchanger 10 and evaporates to become superheated gas. For this reason, since the non-evaporated refrigerant does not flow into the compressor 8, liquid compression is not caused in the compressor, and damage to the compressor can be prevented. At this time, the indoor heat exchanger 3 does not have an overheating region that is higher than the dew point temperature of the inflowing air, so that no dew condensation occurs in the cross-flow fan or the casing as in the effect of the previous embodiment.

  Further, in the case of the present embodiment, as shown in FIG. 7, the refrigerant in the supercooled state that is condensed in the outdoor heat exchanger 10 exchanges heat with the refrigerant that has left the evaporator in the refrigerant heating heat exchanger 15, so Increased cooling. As a result, the dryness of the refrigerant when flowing into the indoor heat exchanger 3 (= evaporator) is reduced, so that the average dryness of the refrigerant from the inlet to the outlet in the indoor heat exchanger 3 is reduced. The pressure loss is reduced, the compressor suction pressure is increased, and the power consumption can be reduced.

  Next, the indoor heat exchanger 3 shown by the said Example is demonstrated using FIG. 8, FIG. FIG. 8 is a view showing a part of the fins 4 of the indoor heat exchanger 3. The fin 4 is provided with a louver 17 in order to improve heat transfer performance. The louvers are cut and raised alternately in the vertical direction, and the total height of the fins including the louver height and the fin thickness is Hf. In the indoor heat exchanger 3, the fins 4 are laminated, and the heat transfer tubes 5 are arranged in a straight line. FIG. 9 shows the present embodiment, and the fin pitch Pf (= fin stacking interval) is set to Pf ≦ Hf. The air for heat exchange flows from left to right as shown by the arrows in the figure, but the fin pitch is narrow and the louvers are densely installed so as to bite into the adjacent fin louvers. For this reason, generation | occurrence | production of the air (bypass air) which does not touch a fin surface is suppressed, and when it uses as an evaporator, it becomes easy to perform cooling dehumidification. Therefore, it is possible to prevent the problem that the bypass air that has not been dehumidified comes into contact with the cross-flow fan or the casing that is cooled by the air that has been cooled and dehumidified in contact with the fins, thereby causing condensation.

The block diagram of the indoor unit which concerns on one Example of this invention. The block diagram of the indoor unit which concerns on one Example of this invention. The block diagram of the air conditioning apparatus which concerns on one Example of this invention. The block diagram of the air conditioning apparatus which concerns on one Example of this invention. The block diagram of the air conditioning apparatus which concerns on one Example of this invention. The block diagram of the air conditioning apparatus which concerns on one Example of this invention. Explanatory drawing of the effect of the invention which concerns on one Example of this invention. FIG. 3 is a structural diagram of a fin according to an embodiment of the present invention. The block diagram of the heat exchanger which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Indoor unit, 2 ... Cross-flow fan, 3 ... Indoor heat exchanger, 4 ... Fin, 5 ... Heat transfer tube, 7 ... Auxiliary heat exchanger, 8 ... Compressor, 10 ... Outdoor heat exchanger, 11 ... Capillary tube, DESCRIPTION OF SYMBOLS 13 ... Electric heater, 14 ... Compressor residual heat utilization heat exchanger, 15 ... Refrigerant heating heat exchanger, 16 ... Check valve.

Claims (7)

  An air conditioner including an indoor unit having an indoor heat exchanger and a cross-flow fan, wherein the number of rows of heat transfer tubes in the air flow direction of the indoor heat exchanger is one.   In an air conditioner including an indoor heat exchanger and an indoor unit having a cross-flow fan, the number of rows of heat transfer tubes in the air flow direction of the indoor heat exchanger is one row, and the indoor heat exchanger and The air conditioner provided with the refrigerant | coolant overheating means which heats the refrigerant | coolant between compressor suction parts.   3. The refrigerant heating means according to claim 2, wherein the refrigerant heating means is an auxiliary heat exchanger, and the auxiliary heat exchanger and the indoor heat exchanger are arranged so that the number of rows of heat transfer tubes in the air flow direction is a plurality of rows. Air conditioner.   The air conditioner according to claim 2, wherein the refrigerant heating means is an electric heater.   3. The air conditioner according to claim 2, wherein the refrigerant heating means is a heat exchanger that uses heat radiated from the compressor as a heat source.   3. The air conditioner according to claim 2, wherein the refrigerant heating means is a heat exchanger that uses heat of the refrigerant between a heat exchanger serving as a condenser and a pressure reducing mechanism during a cooling operation as a heat source. The air conditioner according to claim 1, wherein the fin pitch Pf and the total fin height Hf of the indoor heat exchanger are in a relationship of Pf≤Hf.

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