JP5501094B2 - Refrigeration cycle apparatus and refrigerator, low-temperature apparatus, and air conditioner using this refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus, and more particularly to a vapor compression refrigeration cycle apparatus used in refrigeration equipment, a low temperature apparatus, an air conditioner, and the like.

  In an evaporator (that is, a heat exchanger) of a refrigeration cycle apparatus used in conventional refrigeration equipment and air conditioners, operation is performed so that the evaporation temperature is close to a target temperature in order to improve the performance of the equipment. . However, for example, in the case of having a room with different temperature zones such as a refrigerator or a freezer, such as a refrigerator, the air in each room with different temperature zones is cooled by one evaporator, so high-temperature air containing a large amount of water vapor Is cooled at an evaporation temperature higher than necessary. Therefore, the amount of frost formation to an evaporator increased and there existed a problem which caused the performance fall of an apparatus.

  In order to solve such a problem, a refrigeration cycle apparatus in which two evaporators are provided for air in different temperature zones has been conventionally used. However, in this case, since different evaporation temperatures are generated by a plurality of evaporators for each air state, it is necessary to optimize each evaporator for each purpose of use. For example, the conventional refrigeration cycle apparatus described above has some new configuration in the conventional components such as making the refrigerant itself a non-azeotropic mixed refrigerant, preparing two or two compressors, and using an ejector. It was necessary to prepare equipment.

  On the other hand, in the refrigeration cycle apparatus provided with the above two evaporators, there is one used in the refrigerator described in Patent Document 1, for example, as a solution of the above-described problems using conventional components. In the refrigeration cycle apparatus of Patent Document 1, a first evaporator and a second evaporator are connected in series, and a gas-liquid separator is installed therebetween. Then, the vaporized refrigerant from the gas-liquid separator is passed through the second evaporator to generate two different evaporation temperatures.

JP 2000-258020 A (FIG. 1)

  When new components are prepared in order to optimize the two evaporators for each purpose of use, there is a problem that the apparatus becomes large. Furthermore, since many components and complicated circuits are required, there is a problem that it takes time to manufacture.

  For such an example that requires many components and complicated circuits, as described above, the first evaporator and the second evaporator are connected in series, and a gas-liquid separator is installed between them. In this case, since only the vaporized refrigerant can be flowed, there is a problem that the temperature of the second evaporator cannot be kept below a certain temperature.

  The present invention has been made to solve the above-described problems. When a plurality of evaporators are provided in the refrigeration cycle apparatus, the evaporation temperature of each evaporator can be adjusted in a wide temperature range, and the number of the evaporators is small. The present invention provides a refrigeration cycle apparatus using constituent devices, a refrigeration apparatus using the refrigeration cycle apparatus, a low temperature apparatus, an air conditioner, and the like.

The refrigeration cycle apparatus of the present invention includes a compressor, a condenser, a first expansion device, a regulator, a refrigerant circuit having a plurality of evaporators, and a controller that controls at least the regulator, and the regulation The apparatus includes a gas-liquid separator and a plurality of refrigerant pipes connecting the gas-liquid separator and the evaporator, and the gas-liquid separator side openings of the refrigerant pipes have different heights. Connected to a gas-liquid separator, each of the refrigerant pipes is provided with a refrigerant amount adjusting device, and the refrigerant amount adjusting device is at least one of an opening / closing device and a second expansion device, and the plurality of evaporators At least two of the evaporators are arranged in series with respect to the air flow, and the ratio of the gas phase is large in the plurality of refrigerant pipes connecting the gas-liquid separator and the at least two evaporators. Refrigerant piping through which the refrigerant flows Serial connected to at least two evaporator upstream of the evaporator of the refrigerant pipe through which the refrigerant flows a large percentage of the liquid phase, wherein at least connected to two evaporator downstream of the evaporator, the control unit, when said at least the dew point temperature of the air entering the evaporator of the upstream of the two evaporators predetermined value or more, frost of the evaporator of the upstream is increased As described above, the flow rate of the refrigerant flowing from the regulator to the upstream evaporator is adjusted by controlling the opening / closing of the opening / closing device or the opening of the second expansion device.

The present invention includes at least two evaporators arranged in series with respect to the air flow, a gas-liquid separator, and a regulator having a plurality of refrigerant pipes connecting the gas-liquid separator and the evaporator. When the dew point temperature of the air flowing into the upstream evaporator of at least two evaporators is equal to or higher than a predetermined value , the frosting amount of the upstream evaporator is increased from the regulator. Controlling the flow rate of the refrigerant flowing into the upstream-side evaporator, the opening / closing of the opening / closing device or the opening of the expansion device provided in each of the plurality of refrigerant pipes having different gas-liquid separator side opening heights in because it was and a control unit for adjusting, in small construction equipment, it is possible to adjust the evaporation temperature of the evaporator in a wide temperature range.

It is a refrigerant circuit figure of the refrigerating cycle device which has one conventional evaporator. It is a figure which shows the conventional refrigerating-cycle apparatus which has two evaporators, and a Mollier diagram. It is the figure which showed the evaporator in the conventional refrigeration cycle apparatus. It is the figure which showed the state of the refrigerant | coolant in the evaporator and evaporator of the refrigerating-cycle apparatus in Embodiment 1 of this invention. It is the figure which showed the example of the regulator in Embodiment 1 of this invention. It is a figure around the evaporator in Embodiment 1 of this invention. It is a figure of the evaporator periphery which shows Embodiment 2 of this invention, and the evaporator in a refrigerator. It is the figure of the evaporator periphery of the refrigerator which has two evaporators in Embodiment 2 of this invention, and a refrigerant circuit figure. It is a refrigerant circuit figure of the low-temperature apparatus which has two evaporators in Embodiment 3 of this invention. It is a figure of the showcase which has two evaporators in Embodiment 3 of this invention. It is the figure which showed the flowchart of operation | movement control of the regulator in Embodiment 3 of this invention. It is the figure which showed the outdoor unit of the conventional air conditioner. It is the figure which showed the outdoor unit of the air conditioner in Embodiment 4 of this invention. It is the figure which showed the outdoor unit of the conventional air conditioner, and the indoor unit of the air conditioner in Embodiment 5 of this invention. It is the figure which showed the ventilation state of the indoor unit of the air conditioner in Embodiment 5 of this invention. It is the figure which used the four-way valve for the refrigerator in Embodiment 2 of this invention.

  Hereinafter, the refrigeration cycle apparatus of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
First, a conventional refrigeration cycle apparatus having one evaporator will be described for comparison with the first embodiment.
FIG. 1 is an example of a refrigerant circuit diagram of a conventional general refrigeration cycle apparatus 10 (having one evaporator). In FIG. 1, a refrigeration cycle apparatus 10 having one evaporator is mainly composed of an outdoor unit 11 and an indoor unit 12. The outdoor unit 11 includes a compressor 21 and a condenser 22. The indoor unit 12 includes an expansion device 24, an evaporator 25, and a fan 26. The compressor 21 compresses the refrigerant filled in the refrigeration cycle apparatus 10. The condenser 22 radiates the refrigerant compressed by the compressor 21. The expansion device 24 (for example, an expansion valve) expands the refrigerant radiated by the condenser 22. The evaporator 25 is an example of a heat exchanger, and cools air by exchanging heat between the outside air and the refrigerant expanded by the expansion device 24.

  The refrigeration cycle apparatus 10 performs temperature adjustment, for example, indoors, in a refrigerator, and in a freezer by performing the vapor compression refrigeration cycle operation in this way. The refrigeration cycle apparatus 10 is also used mainly for low-temperature apparatuses (that is, refrigeration equipment) such as unit coolers and showcases. Moreover, the refrigeration cycle apparatus 10 can be similarly used for an air conditioner. When used in an air conditioner, the refrigeration cycle apparatus 10 may be, for example, a heat pump cycle apparatus that heats a fluid (for example, water) that circulates in a flow path. In this case, the condenser 22 heats the fluid (that is, supplies hot water) by exchanging heat between the fluid and the refrigerant compressed by the compressor 21 to dissipate the refrigerant.

  When the refrigeration cycle apparatus having such a configuration is used, for example, a refrigerator having a different temperature zone such as a refrigerator or a freezer compartment cools the air in each chamber having a different temperature zone with a single evaporator. Therefore, high-temperature air containing a large amount of water vapor is cooled at an evaporation temperature higher than necessary. Therefore, the amount of frost formation to an evaporator increased and there existed a problem which caused the performance fall of an apparatus.

FIG. 2 is an example of a conventional refrigeration cycle apparatus 30 having two evaporators, in which (a) is a refrigerant circuit diagram and (b) is a Mollier diagram.
The refrigeration cycle apparatus 30 in FIG. 2A is obtained by adding a second expansion device 31 and a second evaporator 32 to the refrigeration cycle apparatus 10 in FIG. The second expansion device 31 expands the refrigerant that has left the evaporator 25 again (D → E in (b)). Since the second evaporator 32 is in a refrigerant state whose pressure is lower than that of the evaporator 25, the evaporation temperature is lowered. Thus, having two different evaporators in one refrigeration cycle apparatus has two different evaporation temperatures.

  In the refrigeration cycle apparatus 30 having the two evaporation temperatures shown in FIG. 2, as the evaporation temperature of the second evaporator 32 is lowered, the pressure of the refrigerant flowing into the compressor 21 is lowered, and thus the performance of the compressor is lowered. . Further, in order to generate a plurality of evaporation temperatures, a plurality of expansion devices are required, and the evaporation temperature is also limited.

  So far, the conventional refrigeration cycle apparatus has been described for comparison with the first embodiment. Hereinafter, the refrigeration cycle apparatus according to Embodiment 1 of the present invention will be described.

FIG. 3 shows an example of the refrigeration cycle apparatus according to the first embodiment. FIG. 3A is a diagram showing details of the evaporator 25 and the second evaporator 32, and FIG.
In the refrigerant circuit of FIG. 3A, the refrigerant passes through the regulator 40 upstream thereof before passing through the evaporator 25 and the second evaporator 32. As will be described in detail later, the controller 40 is for adjusting the refrigerant state and flow rate to each evaporator.

  FIG. 3B shows an example of fins and heat transfer tube portions of the evaporator used as the evaporator 25 and the second evaporator 32. Here, the fin tube type heat exchanger widely used for the refrigeration apparatus and the air conditioner as an evaporator is shown. The evaporator mainly includes a plurality of fins 41 and a plurality of heat transfer tubes 42. A plurality of fins 41 are stacked at a predetermined interval, and a plurality of heat transfer tubes 42 are provided so as to penetrate through holes provided in the fins 41. The liquid refrigerant flowing through the heat transfer tube 42 is vaporized to absorb heat and exchange heat with the external air via the fins 41.

Here, the heat exchange process between the refrigerant in the pipe and the air to be heat-exchanged (hereinafter referred to as external air) will be described using equations. The amount of heat exchange between the refrigerant in the tube and the external air follows the following relational expression.
Qer = Gr (Hei-Heo) (1)
Qep = Aeiαi (Tp−Teg) (2)
Qea = Aeoαo (Tea−Tp) (3)

  Here, Qer, Qep, and Qea represent the refrigerant side heat exchange amount, the in-pipe heat exchange amount, and the air side heat exchange amount. Gr represents the refrigerant flow rate, and Hei and Heo represent the refrigerant inlet enthalpy and the outlet enthalpy. Aei and Aeo represent the heat transfer area inside the tube and the heat transfer area outside the tube. αi and αo represent the in-tube heat transfer coefficient and the out-tube heat transfer coefficient. Tp, Teg, and Tea represent the heat transfer tube temperature, the refrigerant temperature, and the external air temperature.

  The above formulas (1) to (3) have a relationship of Qer = Qep = Qea due to thermal balance. By these simultaneous equations, for example, values (Aei, Aeo, αi, αo) relating to the shape of the evaporator and the inflowing air are given, and values relating to the refrigerant state (Gr, Hei, Teg) are given, whereby Tp and Qea can be calculated. .

Below, the difference in the amount of heat exchange when the refrigerant state is gas-liquid two-phase and when it is gas will be described. In the above formula (2), the heat transfer coefficient αi in the pipe is greatly different between the gas-liquid two-phase and the gas, and in particular, the gas-liquid two-phase is also different depending on the flow shape (for example, slag flow or annular flow). (Refer to Corona, written by Hiroaki Akagawa). Generally, αi is about 200 [W / m ² K] for gas, αi is about 2000 [W / m ² K] for two-phase, and αi is about 10 times that of gas in the gas-liquid two-phase. Due to this difference in heat transfer coefficient, for example, in the same shape of evaporator, even if the refrigerant temperature Teg is the same and Qep (or Qer) is the same, the heat transfer tube temperature Tp is different due to the difference in heat transfer coefficient αi in the tube, In the gas-liquid two phase, Tp is higher for gas.

FIG. 4 is a diagram showing an example of an evaporator used in the evaporator 25 and the second evaporator 32 in the first embodiment. FIG. 4A shows one heat transfer tube 42 in the evaporator. It is the fin 41 of the circumference | surroundings, (b) is sectional drawing of one heat exchanger tube, and is a figure explaining each state of a heat exchanger tube, a refrigerant | coolant, and external air.
For example, even if the refrigerant state flowing into the heat transfer tube 42 is a gas-liquid two-phase, the heat transfer tube temperature Tp is increased by becoming a gas in the middle of the tube as shown in FIG. 4B. As a result, two types of heat transfer tube temperatures, Tp1 (gas-liquid two-phase tube wall temperature) and Tp2 (gas phase tube wall temperature), are generated in the heat exchanger. That is, as the refrigerant state (dryness) at the inlet of the evaporator is closer to the gas phase (dryness is closer to 1), the proportion of gas in the heat exchanger increases and Tp increases.

  Here, the external air state after passing through the evaporator is considered. The external air flowing into the evaporator is cooled by heat exchange of Qea according to the temperature difference between the heat transfer tube temperature Tp and the external air temperature Tea according to Equation (3). In other words, if the inflowing external air temperature is the same, the lower the Tp, the larger the Qea and the lower the blowing air temperature. The external air flowing into the evaporator is dehumidified if Tp is equal to or lower than the dew point temperature of the external air, and is frosted on the evaporator if it is 0 ° C. or lower. The greater the heat exchange amount, the greater the amount of frost formation (dehumidification amount). From the above, the temperature of the blown air by adjusting the state of the refrigerant flowing into the evaporator (specifically, whether it is in the gas phase or the gas-liquid two phase, or the dryness in the case of the gas-liquid two phase) Can be adjusted, and the amount of frost formation (dehumidification amount) can be adjusted by adjusting the temperature difference between Tp and Tea (adjusting Qea).

Here, the controller for adjusting the refrigerant state flowing into the evaporator in order to adjust the heat transfer tube temperature Tp will be described.
The role of the regulator 40 on the refrigeration cycle is to regulate the state of refrigerant (dryness of the refrigerant) and the flow rate flowing into the individual evaporators located downstream of the regulator 40. Here, regarding the flow rate of the refrigerant, since the flow rate of the refrigerant flowing individually is determined by the pressure loss caused by the flow of the refrigerant in each evaporator, the range that can be controlled by the regulator 40 is determined.

(A), (b), (c), and (d) of FIG. 5 are examples of the regulator in this Embodiment 1, respectively.
In the regulator 40 of FIG. 5A, a refrigerant pipe 48 is connected to the gas-liquid separator 47, and each refrigerant pipe 48 is provided with a valve 43 (a refrigerant flow rate adjusting device in the present invention). The refrigerant pipes are connected to different evaporators. The valve may be, for example, an expansion valve such as LEV (expansion device in the present invention) or an opening / closing device. The valve 43 plays a role of increasing the pressure loss and reducing the refrigerant flow rate downstream by taking into account the pressure loss of the individual evaporators downstream of the valve 43.

  Next, adjustment of the refrigerant state will be described. Since the refrigerant flowing into the gas-liquid separator 47 is in a gas-liquid two-phase or liquid phase, the liquid accumulates in the lower part of the gas-liquid separator 47. Therefore, as shown in FIG. 5, if the refrigerant pipes 48 flowing from the gas-liquid separator 47 to the individual evaporators are installed in order from the bottom, the refrigerant can be flowed to the individual evaporators in various refrigerant states. Further, for example, by adjusting the diameter of the inflow pipe, the flow rate of the inflowing refrigerant can be adjusted even if the valve 43 is not provided.

  In the regulator 40b of FIG. 5B, refrigerant pipes 48b connected to different evaporators are connected above and below a gas-liquid separator 47b constituted by pipes. The refrigerant flowing into the gas-liquid separator 47b is separated by colliding with the pipe. Then, the refrigerant having a large gas phase ratio flows into the upper refrigerant pipe 48b, and the refrigerant having a large liquid phase ratio flows into the lower refrigerant pipe 48b.

  The regulator 40c in FIG. 5C includes a gas-liquid separator 47c and a refrigerant pipe 48c connected to different evaporators. The gas-liquid separator 47c includes two containers 47c2 that store the refrigerant and a communication pipe 47c1 that connects the two containers 47c2. The interiors of the two containers 47c2 are configured to store a gas-liquid two-phase refrigerant and separate it into a gas refrigerant and a liquid refrigerant. That is, the refrigerant having a large gas phase ratio is stored in the upper part, and the refrigerant having a large liquid phase ratio is stored in the lower part. And the refrigerant | coolant with a large ratio of a gaseous phase flows in into one refrigerant | coolant piping 48c via the upper communication pipe 47c1. Further, the refrigerant having a large liquid phase ratio flows into the other refrigerant pipe 48c provided with the refrigerant inlet at the lower portion of the container 47c2.

  The adjuster 40d in FIG. 5D includes a conical gas-liquid separator 47d and a refrigerant pipe 48d connected to different evaporators of the gas-liquid separator 47d. The gas-liquid separator 47d is a kind of centrifuge, and the gas-liquid separation can be promoted by rotating the refrigerant in the gas-liquid separator 47d. Then, the refrigerant having a large gas phase ratio flows into the upper refrigerant pipe 48d, and the refrigerant having a large liquid phase ratio flows into the lower refrigerant pipe 48d.

  In the regulators 40b, 40c, and 40d described above, the flow rate is adjusted by providing a valve (expansion device or switching device) in each refrigerant pipe or adjusting the pipe diameter of each refrigerant pipe in the same manner as the regulator 40. May be. Moreover, in the regulators 40, 40b, 40c, and 40d described above, the state of the refrigerant flowing into each evaporator may be changed by changing the height of the opening through which the refrigerant flows into each refrigerant pipe. Moreover, in the regulators 40, 40b, 40c, and 40d described above, any number of pipes may be connected to the gas-liquid separator. For example, when there are two pipes, the refrigerant pipe through which the refrigerant having a large gas phase ratio flows is connected to the second evaporator 32 in FIG. 3, and the refrigerant pipe through which the refrigerant having a large liquid phase ratio flows is the evaporation pipe in FIG. Connect to the device 25.

  As described above, when two or more different evaporators are used, the gas-liquid separator 47 is connected to each evaporator by the refrigerant pipe 48, the valve 43 is provided in the refrigerant pipe, and the controller 40 controls the regulator 40. By doing so, the refrigerant state and flow rate can be adjusted. Thus, the evaporation temperature of each evaporator can be adjusted in a wide temperature range with a small number of components.

  FIG. 6 is a schematic diagram showing an example of the evaporator and its peripheral configuration of the refrigeration cycle apparatus according to the first embodiment. In FIG. 6, the evaporator fan 45 is installed on the leeward side of the evaporator 44, but the evaporator fan 45 is installed on the leeward side of the evaporator 44, and air may be sent in. In any case, there is not always a clear air path guide like the evaporator air path 46, but the air sent by the fan is designed to pass through the evaporator 44 reliably.

In the above air path configuration, examples of inflow / outflow air states (temperature Tin · Tout, humidity φin · φout) of various air-conditioning / cooling devices such as a refrigeration device, a low-temperature device, and an air-conditioning device are shown.
・ Inflow air state Refrigerator (from refrigerator) Tin = 5 ℃ φin = 80%
(From the freezer compartment) Tin = −15 ° C. φin = 60%
Low-temperature equipment (for refrigeration) ... Tin = -15 ° C φin = 60%
Air conditioner (cooling) ... Tin = 27 ℃ φin = 47%
Air conditioner (during heating) ... Tin = 7 ℃ φin = 86%
Air conditioner (at low outside air heating) ... Tin = 2 ℃ φin = 83%
・ Outflow air condition Refrigerator ・ ・ ・ Tout = -30 ℃ φout = 80%
Low temperature device (for refrigeration) Tout = -30 ° C φout = 80%
Air conditioner (cooling) ... Tout = 16 ° C φout = 90%
Air conditioner (when heating) ... Tout = 4 ℃ φin = 90%
Air conditioner (at low outside air heating) ... Tin = -3 ° C φin = 90%

  As described above, in the evaporators of various air-conditioning refrigeration equipment, the evaporator surface temperature Tp is lower than the incoming air (10 to 20 ° C. for low-temperature equipment and about 5 to 10 ° C. for air-conditioning equipment). is there. Therefore, the inflow air is cooled and flows out as described above. At this time, dehumidification or frost formation is caused by cooling, so that the moisture content of the outflow air is reduced as compared with the inflow air. In particular, when frost formation is involved, the front surface of the evaporator 44 is blocked by frost, which makes it difficult to send air by the evaporator fan 45 and causes the performance of the evaporator 44 to deteriorate.

On the other hand, by using the regulator 40 in the first embodiment, different evaporation temperatures are generated by adjusting the refrigerant state flowing into the evaporator for two or more evaporators. For example, the evaporator on the upstream side of the air flow changes the specific air state, and the load processing of the apparatus is mainly performed in the evaporator on the downstream side. A space-saving and highly efficient device is obtained by adjusting the temperatures of both evaporators so that they do not form frost on the downstream evaporator.
Below, the example which used the refrigerating-cycle apparatus in this Embodiment 1 for an air conditioner etc. is shown.

Embodiment 2. FIG.
In Embodiment 2, a refrigerator using the refrigeration cycle apparatus described in Embodiment 1 is described.
First, a conventional refrigerator will be described for comparison with the second embodiment.

FIG. 7 is a view showing a conventional refrigerator, (a1) is a front view of the entire refrigerator, and FIG. 7 (a2) is a side sectional view of the entire refrigerator. Moreover, FIG.7 (b) is an evaporator (cooler) vicinity figure in a refrigerator.
Air is introduced into the evaporator 51 from the refrigerator compartment / freezer compartment by a fan 52, cooled, and sent to the refrigerator compartment / freezer compartment. In other words, different air temperatures (about 5 ° C. in the refrigerator compartment and about −15 ° C. in the freezer compartment) are cooled by one evaporator 51 (the surface temperature of the evaporator 51 is around −30 ° C.), and are supplied to the refrigerator compartment / freezer compartment. Adjust the air volume (for example, using a damper or the like) to cool the refrigerator compartment / freezer compartment to the target temperature.

  The temperature of the evaporator 51 is cooled to close to −30 ° C. in order to maintain the temperature of the freezer compartment having a low target temperature. At this time, since the inflow air from the refrigerator compartment flows into the evaporator 51 in a high temperature and high humidity state (because it may pass through the vegetable compartment), a large amount of frost is generated in the evaporator 51. Due to the frost formation, the fins of the evaporator 51 are closed, and the air volume of the evaporator 51 is reduced to lower the performance. Therefore, the refrigerator needs to perform a defrosting operation regularly and requires extra energy such as a heater during the defrosting. Further, in cooling the inflow air from the refrigerating room, the cooling efficiency of the apparatus is low because the difference between the target refrigerating room temperature and the evaporator temperature is large.

So far, the conventional refrigerator has been described for comparison with the second embodiment. Here, the refrigerator of this Embodiment 2 using the refrigeration cycle apparatus of this Embodiment 1 is demonstrated.
FIG. 8 is an evaporator and refrigerant circuit diagram according to the second embodiment, and (a1) and (a2) are structures around the evaporator according to the second embodiment. 8 (a1) and 8 (a2), the refrigerating room return air 61 has a structure that flows into the evaporator 51 after passing through the second evaporator 62. In FIG. 8 (a1), the position of the second evaporator 62 is installed in the lower part of the evaporator 51. However, as shown in FIG. 8 (a2), the second evaporator 62 is placed at the position where the refrigerating room return air 61 is blown out. Even if 62 is installed, the same effect can be obtained. In addition, the mounting position of FIG. 8 (a1) and (a2) in a refrigerator may be the position shown to FIG. 7 (a2) similarly to the past, for example.

  FIG. 8B is a refrigerant circuit around the evaporator of the refrigerator in the second embodiment. Before the refrigerant passes through the evaporator 51 and the second evaporator 62, the refrigerant passes through an upstream gas-liquid separation and refrigerant amount regulator (hereinafter referred to as a regulator 63). The adjuster 63 may be anything that can adjust the state of the refrigerant flowing through the second evaporator 62, such as the example in the first embodiment of FIG. For example, if the temperature of the refrigerating room return air 61 is 5 ° C. and the humidity is 80%, the controller 63 determines the surface temperature Tp of the second evaporator 62 as the dew point temperature of the refrigerating room return air 61. The refrigerant state to the 2nd evaporator 62 is adjusted so that it may become 8 degreeC vicinity. The controller 63 can store the relationship between Tp and the refrigerant state in a storage unit such as a microcomputer (corresponding to the control unit in the present invention) in advance, thereby enabling the above control.

  Further, for example, when the dew point temperature of the refrigerating room return air 61 is 0 ° C. or lower, the regulator 63 increases the surface temperature Tp as much as possible to reduce the amount of frost that forms on the second evaporator 62. For example, as described above, if the temperature of the return air 61 in the refrigerator compartment is 5 ° C. and the humidity is 80%, the amount of frost on the evaporator 51 can be reduced by setting Tp to about −5 ° C.

  Thus, by adjusting the state of the refrigerant flowing in the second evaporator 62, the moisture in the refrigerating chamber return air 61 is reduced in the second evaporator 62 and flows into the evaporator 51. For example, when air of unit mass (1 kg), temperature of 5 ° C. and humidity of 80% flows in, the amount of water at the time of inflow is 4.3 g. When the air having this moisture content exchanges heat with the second evaporator 62 having a Tp of −5 ° C. and flows out at a temperature of −5 ° C. and a humidity of 100%, the moisture content at the time of blowing becomes 2.6 g. In this case, approximately half of the moisture can be dehumidified by the second evaporator 62 (frosted). If the second evaporator 62 is not provided and heat exchange is performed with the evaporator 51 having a Tp of −30 ° C., the refrigerating room return air 61 having a temperature of −30 ° C. and a humidity of 100% has a water content when flowing out of the evaporator 51. Is only 0.3 g. 4.0 g adheres to the evaporator 51. As described above, by using the second evaporator 62, the amount of frost formed on the evaporator 51 can be reduced, and the performance can be maintained.

  Further, by using the second evaporator 62, the refrigerating room return air 61 is cooled by the second evaporator 62 and flows into the cooler, so that the evaporation temperature of the evaporator 51 is changed by the second evaporator 62. It can rise more than when it is not. That is, when there is no second evaporator 62, the evaporator 51 used to cool the refrigerator return air 61 from the high temperature refrigerator compartment and the refrigerator return air 64 from the low temperature refrigerator compartment. The evaporation temperature was lowered to cool the water. However, by using the second evaporator 62, the return air 61 from the high-temperature refrigerator compartment is pre-cooled (pre-defrosting), and the temperature of the air flowing into the evaporator 51 is lowered. Even if the evaporation temperature of the vessel 51 is increased, the refrigerator can be cooled to the target temperature, and the efficiency of the device can be increased.

  Further, for example, when the refrigerator door is opened or closed, or when a load on the refrigerator (increase in temperature or humidity) is detected, such as when food has flowed into the refrigerator, the regulator 63 may be operated. In this way, by adjusting the refrigerant flowing to the second evaporator 62 at the required temperature when necessary, pre-dehumidification of the refrigerator return air 61 from the refrigerator compartment becomes possible, and the load on the evaporator 51 is reduced. This leads to energy saving of the equipment.

Embodiment 3 FIG.
FIG. 9 is a refrigerant circuit diagram of a low-temperature apparatus used for a freezer warehouse or a refrigerator-freezer display shelf according to the third embodiment.
The regulator 73 in FIG. 9 only needs to be able to adjust the state of the refrigerant flowing in the second evaporator 72, such as the example shown by the regulator 40 in the first embodiment in FIG. Adjustment of the refrigerant state and the refrigerant flow rate to the first evaporator 71 and the second evaporator 72 flowing downstream of the regulator 73 is a detector that detects the cooling chamber temperature and humidity (corresponding to the measurement unit in the present invention). 74. The controller 100 changes the refrigerant state to the second evaporator 72 by controlling the regulator 73 based on the information from the detector 74.

Up to this point, the conventional low-temperature apparatus has been described for comparison with the third embodiment.
Here, an example of the configuration and operation control when the refrigeration cycle apparatus described in the first embodiment is installed in a showcase (corresponding to a cooling chamber in the present invention) will be described with reference to FIGS. 10 and 11.
FIG. 10 is a diagram in which the second evaporator 72, the controller 73, the detector 74, and the first evaporator 71 are installed in the showcase in the third embodiment. For example, a detector 74 is installed in an air suction portion in the showcase. The detector 74 can detect the state of inflow air, such as a temperature and humidity meter. When the detector 74 detects a cooling chamber load such as a rise in temperature or humidity in the inflowing air, information is transmitted to the control unit, and the control unit immediately measures the dew point temperature of the inflowing air. Here, the detection of the internal load is not limited to temperature or humidity, but may be electrical resistance or the like. In addition, in this operation control, the following procedure can be performed by another method as long as the moisture content of the incoming air can be detected.

  FIG. 11 shows operation control of the low temperature apparatus according to the third embodiment. First, in step S1, the detector 74 detects a load. For example, if the inflow air dew point temperature is lower than the temperature A (a state in which a slight amount of water is mixed in a normal air state) (step S2), the controller 100 does not have a great cooling chamber load. The controller operation 1 (the refrigerant does not flow to the second evaporator 72) is executed (step S4). Next, when the temperature is equal to or higher than the temperature A and equal to or lower than the temperature B (a certain amount of moisture mixed state) (step S3), the control unit 100 enters the controller 73 into the controller operation 2 (the surface temperature of the second evaporator 72 flows). (Appropriate refrigerant is flowed so as to be below the air dew point temperature) (step S5). Note that the control unit 100 has a table in which the surface temperature of the second evaporator 72 can be calculated from the inflow air and the inlet refrigerant state in advance, and the controller 73 is adjusted accordingly. By performing the regulator operation 2, the pre-dehumidification of the incoming air can be performed, and the amount of frost formation on the first evaporator 71 can be reduced. Further, when the inflow air dew point temperature is equal to or higher than the temperature B (step S3), since it can be determined that the inflow air contains a large amount of water, the regulator 73 actively causes the refrigerant to flow through the second evaporator 72 (regulation). Operation 3) (step S6). By doing so, a large amount of moisture is frosted on the second evaporator 72, and after a certain amount of frosting has been performed, the flow of the refrigerant to the second evaporator 72 is stopped. By doing so, it is possible to reduce the amount of frost on the first evaporator 71, while a large amount of frost is formed on the second evaporator 72. Therefore, by performing defrosting mainly on the second evaporator 72, it becomes possible to perform an efficient defrosting operation.

  By providing the adjuster 73 as described above, the amount of frost on the first evaporator 71 is reduced, which leads to an improvement in the performance of the device. Moreover, since the frequency | count of defrosting can be reduced, it becomes energy saving and can change the temperature change in a store | warehouse | chamber, Therefore It becomes an apparatus suitable also for food storage. Moreover, since defrost can also be performed efficiently, it leads to shortening of a defrost time.

Embodiment 4 FIG.
FIG. 12A shows an outdoor unit of a conventional air conditioner.
Conventionally, as shown in FIG. 12, an evaporator 105 is installed on the wind of the evaporator fan 103, and air is introduced into the evaporator 105 by the evaporator fan 103, and the refrigerant and air in the evaporator 105 exchange heat. I do.

FIG. 13A is a perspective view of a fin-and-tube type outdoor unit in the air-conditioning apparatus according to Embodiment 4, and FIG. 13B is a top view thereof.
In the fourth embodiment, as shown in FIGS. 13A and 13B, the outdoor unit in the fourth embodiment is provided with the second evaporator 101 on the windward side in the wind flow direction. Here, the refrigerant flows into the second evaporator 101 from the regulator. In addition, this regulator should just be what can adjust the refrigerant | coolant state which flows into the 2nd evaporator 62, such as the example shown with the regulator 63 in Embodiment 1 of FIG. The control is performed by the control unit in accordance with the amount of moisture in the outside air such as outside temperature and humidity. In addition, what is necessary is just to install the external temperature humidity measuring apparatus 104 (equivalent to the measurement part in this invention) on the windward side, for example, as shown to Fig.13 (a).

  For example, when the outside air has a temperature of 2 ° C. and a humidity of 86%, the dew point temperature is approximately 0 ° C. At this time, the control unit adjusts the state of the refrigerant flowing to the second evaporator 101 so that the surface temperature of the second evaporator 101 is 0 ° C. or slightly lower than 0 ° C. By doing so, the amount of frost formation on the second evaporator 101 becomes small. In other words, the heat exchange is almost only sensible heat. Therefore, it is not necessary to consider air passage blockage due to frost, and it is possible to use, for example, a slit type fin having a large effective fin area for the second evaporator 101. By doing so, the size of the outdoor unit necessary to maintain the same capability can be reduced, and the device can be made compact.

  Moreover, since the 1st evaporator 102 cools the air after passing the 2nd evaporator 101, it is clear that frost formation arises and needs to worry about clogging by frost formation. In order to suppress a decrease in air volume due to frost formation, for example, the first evaporator 102 can increase the operation efficiency even in a low temperature environment by widening the fin pitch or changing the fin shape than the second evaporator 101. . Moreover, if frost formation can be reduced, the frequency | count of a defrost operation can be reduced, and since the frequency | count that the performance of an air-conditioner falls during a defrost operation also decreases, comfort can be improved.

Embodiment 5 FIG.
As an example using the refrigeration cycle apparatus of the first embodiment, the effect of preventing frost formation and the like has another effect by a method as described below, for example.
Fig.13 (a) is sectional drawing of the indoor unit of the conventional air conditioner, and uses the fin and tube type heat exchanger. FIG. 13B is a sectional view of the indoor unit of the air conditioner according to the fifth embodiment. In addition, when the indoor unit is performing heating operation, the heat exchanger of the outdoor unit is operating as the first evaporator.

First, an indoor unit of a conventional air conditioner will be described for comparison with the fifth embodiment.
The condenser 113 of the conventional air conditioner heats and blows in flowing room air. Incoming air passes through a path as shown by a broken-line arrow in FIG.

FIG. 15A shows a state in which heated air is blown out from a conventional indoor unit. When the uniformly heated air is blown out from the blowing section 114, the density of the heated air is smaller than the density of the indoor air (the air density at 20 ° C. is 1.189 kg / m ³ , and the air at 30 ° C. The density is 1.150 kg / m ³ ) and rises in the room after blowing. For this reason, the vicinity of the floor is not easily warmed and the comfort is impaired, and it is necessary to increase the heating set temperature more than necessary or raise the wind speed more than necessary, thereby increasing the power consumption of the air conditioner.

  In the fifth embodiment, in order to suppress such an increase due to the density difference of the heated air, the second evaporator 111 is mounted on the indoor unit as shown in FIG. Compared to the conventional indoor unit in FIG. 14A, the second evaporator 111 is installed after passing through the condenser 113. That is, the heated air is cooled by the second evaporator 111.

  Here, after passing through the condenser 113, the air that has passed through the second evaporator 111 passes through the fan 112 and is blown out from the upper part of the blowing part 114. In addition, after passing through the condenser 113, the air that does not pass through the second evaporator 111 passes through the fan 112 and is blown out from the lower part of the blowing unit 114. That is, the air blown out from the blow-out part 114 is air whose upper part is low temperature and whose lower part is hot. And as shown in FIG.15 (b), the upper air suppresses a raise of the lower air.

  Note that the surface temperature of the second evaporator 111 is adjusted by the adjuster in the same manner as in the first embodiment. Here, in the fifth embodiment, the refrigerant state to the second evaporator 111 is adjusted in advance so as to have a necessary density difference depending on the set temperature of the blowing temperature.

  Thereby, since the warmed blowing air can be effectively blown to the user, it is comfortable for the user and the power consumption of the air conditioner can be suppressed.

  Although the second evaporator 111 is installed after the condenser 113 is blown out, the second evaporator 111 may be installed before the condenser 113 flows in to cool the inflow air in advance. Further, the air cooled by the second evaporator 111 may be structured not to flow into the condenser 113. Even in this case, the blown air temperature distribution similar to the above can be provided, and the same effect can be obtained.

Although Embodiments 1 to 5 have been described above, the present invention is not limited to the configuration described above.
For example, the regulator in the present invention may have a mechanism that can be fully closed when there is no purpose of using the second evaporator, so that the normal circuit is not affected. The present invention is applicable not only to the devices shown in the first to fifth embodiments, but also to a car air conditioner, for example.

  Moreover, the defrosting apparatus of the refrigerating cycle apparatus shown by the above embodiment may be based on external heat sources, such as a heater, for example. For example, when installing a heater in the refrigerator of Embodiment 2, it installs in the position of the heater 57 of FIG. Here, the heater 57 only needs to be able to defrost the second evaporator 62 or the evaporator 51, and may not be at the position shown in FIG. Similarly, in other embodiments, it is possible to defrost using an external heat source such as a heater.

Also, the defrosting operation can be performed by a reverse flow of refrigerant or a hot gas method using discharge gas.
FIG. 16 shows a refrigeration cycle apparatus in which a four-way valve 69 is provided in the refrigerator of the second embodiment so that the refrigerant can flow in reverse. The refrigerant during normal operation circulates in the order of the condenser 22, the regulator 63, the evaporator 51, the second evaporator 62, and the compressor 21. On the other hand, at the time of the defrosting operation, by switching the four-way valve, the refrigerant flows through the reverse of the normal operation, thereby sending the high-temperature refrigerant discharged by the compressor to the evaporator 51 or the second evaporator 62 and defrosting. . Similarly, in other embodiments, the defrosting operation can be performed by the method using the above-described four-way valve 69.

  10, 30 Refrigeration cycle device, 11 Outdoor unit, 12 Indoor unit, 21 Compressor, 22 Condenser, 23 Condenser fan, 24 Expansion device, 25 Evaporator, 26 Fan, 31 Second expansion device, 32 Second Evaporator, 40 Controller, 41 Fin, 42 Heat transfer tube, 43 Valve, 45 Evaporator fan, 46 Evaporator air path, 50 Refrigerator, 51 Evaporator, 52 Fan, 53 Inside, 54 Wall, 55 Thermal insulation wall, 56 Compressor, 57 heater, 61 refrigerator compartment return air, 62 second evaporator, 63 regulator, 64 freezer compartment return air, 69 four-way valve, 71 first evaporator, 72 second evaporator, 73 regulator , 74 detector, 100 control unit, 101 second evaporator, 102 first evaporator, 103 evaporator fan, 104 outside air humidity measuring device, 105 evaporator, 111 second Evaporator, 112 fans, 113 condenser, 114 balloon portion.

Claims (9)

A compressor, a condenser, a first expansion device, a regulator, and a refrigerant circuit having a plurality of evaporators, and a controller that controls at least the regulator,
The regulator includes a gas-liquid separator, and a plurality of refrigerant pipes connecting the gas-liquid separator and the evaporator,
The gas-liquid separator side opening of the refrigerant pipe is connected to the gas-liquid separator so as to have different heights, respectively.
A refrigerant amount adjusting device is provided in each of the refrigerant pipes,
The refrigerant amount adjusting device is at least one of an opening / closing device and a second expansion device,
At least two of the plurality of evaporators are arranged in series with the air flow;
Among the plurality of refrigerant pipes connecting the gas-liquid separator and the at least two evaporators, a refrigerant pipe through which a refrigerant having a large gas phase ratio flows is upstream of the at least two evaporators. A refrigerant pipe connected to the evaporator and through which a refrigerant having a large liquid phase ratio flows is connected to an evaporator on the downstream side of the at least two evaporators,
The control unit, the at least when the dew point temperature of the air entering the evaporator of the upstream of the two evaporators is predetermined value or more, frost of the evaporator of the upstream Refrigeration characterized in that the flow rate of the refrigerant flowing from the regulator into the upstream evaporator is adjusted by controlling the opening / closing of the opening / closing device or the opening of the second expansion device so as to increase. Cycle equipment. A measurement unit for measuring the temperature and humidity of the air flowing into the upstream evaporator,
The control unit calculates the dew point temperature based on the temperature and the humidity measured by the measurement unit, and determines a flow rate of the refrigerant flowing from the regulator to the upstream evaporator based on the dew point temperature. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is adjusted.   The control unit includes a storage unit that stores a relationship between a surface temperature of the upstream evaporator and a flow rate of the flowing refrigerant, calculates a surface temperature of the upstream evaporator from the dew point temperature, The refrigeration cycle apparatus according to claim 2, wherein the flow rate of the refrigerant flowing in is adjusted based on a surface temperature and the stored relationship.   The said control part performs the defrost operation using an external heat source, The refrigeration cycle apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.   The said control part performs the defrost operation which flows the refrigerant | coolant which the compressor discharged to the said evaporator, The refrigeration cycle apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.   The evaporator includes a plurality of fins installed at predetermined intervals from each other, and a heat transfer tube penetrating the plurality of fins, and the refrigerant flowing through the heat transfer tube via the fins and the The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the air flowing into the evaporator exchanges heat. The refrigeration cycle apparatus according to any one of claims 1 to 6, and two or more chambers having different temperature zones,
Of the at least two evaporators, the upstream-side evaporator cools the air flowing in from the higher temperature chamber of the two or more chambers, and the cooled air and the temperature zone The refrigerator, wherein the downstream evaporator of the at least two evaporators cools the air flowing in from the lower chamber to a lower temperature. A refrigeration cycle apparatus according to any one of claims 1 to 6, and a cooling chamber,
In the air flow path formed in the cooling chamber, the at least two evaporators are arranged in series with the air flow,
In the flow path, the at least two of the upstream side of the evaporator of the evaporator, the at least two low temperature and wherein the than the downstream evaporator of the evaporator at a high temperature. Comprising the refrigeration cycle apparatus according to any one of claims 1 to 6,
The at least two evaporators are provided in an outdoor unit;
In the air flow path formed in the outdoor unit, the at least two evaporators are arranged in series with respect to the air flow,
In the flow path, the at least two of the upstream side of the evaporator of the evaporator, said at least an air conditioning apparatus, wherein the one of the two evaporators than the downstream side of the evaporator at a high temperature.

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