WO2014021076A1

WO2014021076A1 - Refrigerator

Info

Publication number: WO2014021076A1
Application number: PCT/JP2013/069035
Authority: WO
Inventors: 雄亮田代; 中津　哲史; 西澤　章
Original assignee: 三菱電機株式会社
Priority date: 2012-07-30
Filing date: 2013-07-11
Publication date: 2014-02-06
Also published as: JPWO2014021076A1; JP5818993B2; CN104508408B; CN104508408A; SG11201408426WA

Abstract

A refrigerator is provided with a refrigeration cycle formed by connecting a compressor, a condensing pipe, a pressure reduction device, a dew formation prevention pipe, a capillary tube, and a cooler in this order. The pressure reduction device is configured so as to be capable of adjusting the flow resistance of a refrigerant in two stages of flow resistance which are first flow resistance and second flow resistance which is smaller than the first flow resistance.

Description

refrigerator

The present invention relates to a refrigerator having a condensation prevention pipe for preventing condensation.

Conventionally, there is a refrigerator having a dew condensation prevention pipe (or also referred to as a cabinet pipe or a dew prevention pipe) for preventing dew condensation. Many of such refrigerators have a condensation prevention pipe installed at the periphery of the opening of the refrigerator body. And the dew condensation prevention pipe is heated by condensing the high-pressure refrigerant discharged from the compressor with the dew condensation prevention pipe, and dew condensation on the periphery of the opening of the refrigerator body is prevented.
However, the refrigerant in the dew condensation prevention pipe is installed on the back, top or side of the refrigerator main body and is condensed at the same refrigerant pressure as the condensation pipe for condensing the refrigerant. Is heated, and there is a problem that an extra compressor input is required.

For this reason, various refrigerators have been proposed in which the flow rate of refrigerant to the condensation prevention pipe is adjusted so that the condensation prevention pipe is not heated more than necessary. As such, a refrigerant flow distribution device (7) is interposed between the heat radiation capacitor (2a) and the dew condensation prevention capacitor (2b), and the dew condensation prevention capacitor and the dew condensation capacitor according to the temperature difference between the ambient temperature and the dew condensation prevention capacitor. There has been proposed a refrigerator in which refrigerant is distributed to the bypass pipe (6) so that the periphery of the opening of the refrigerator body is not heated more than necessary (for example, see Patent Document 1).

JP-A-8-285426 (see, for example, FIG. 1)

In the technique described in Patent Document 1, the refrigerant flow rate to the dew condensation prevention pipe changes depending on the refrigerant flow rate to the bypass pipe. Moreover, the refrigerant | coolant flow rate of a refrigerator is small compared with an air conditioning apparatus etc., for example. That is, in the technique described in Patent Document 1, when the refrigerant flow rate to the dew condensation prevention pipe is reduced, the refrigerant flow rate flowing through the dew condensation prevention pipe becomes very small, and it is necessary to heat the dew condensation prevention pipe to a target temperature. Time (response time) becomes longer. For this reason, the technique described in Patent Document 1 has a problem that the temperature of the dew condensation prevention pipe cannot be stabilized.

Further, in the refrigerator as described in Patent Document 1, the dew condensation prevention pipe is provided at a position close to the interior of the refrigerator, and a heat insulating structure with the interior is not taken through a heat insulating material or the like. For this reason, most of the condensation heat from the dew condensation prevention pipe 13 penetrates into the inside of the box, increasing the load inside the box, and accordingly, it is necessary to operate the compressor, and the power consumption increases. There was a problem.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a refrigerator that can stabilize the temperature of a dew condensation prevention pipe and can reduce power consumption. .

A refrigerator according to the present invention includes a compressor, a condensing pipe, a decompression device, a dew condensation prevention pipe, a capillary tube, and a refrigeration cycle in which a cooler is connected in this order. The flow resistance is adjusted in two stages, ie, a first flow resistance and a second flow resistance smaller than the first flow resistance.

According to the refrigerator of the present invention, since the flow resistance of the refrigerant flowing through the decompression device is configured to be two stages of the first flow resistance and the second flow resistance smaller than the first flow resistance, The temperature of the condensation prevention pipe can be stabilized.
Further, according to the refrigerator of the present invention, the condensing pipe, the decompression device, and the dew condensation prevention pipe are connected, and the refrigerant temperature of the dew condensation prevention pipe is lowered with respect to the condensation pipe by the decompression device, so that the internal temperature and the dew condensation prevention pipe are reduced. The temperature difference can be reduced. As a result, the heat of condensation entering the interior from the dew condensation prevention pipe is reduced, and the power consumption can be reduced by the amount that the compressor input can be reduced.

It is a figure explaining the structure of the refrigerating cycle of the refrigerator which concerns on Embodiment 1 of this invention. It is a figure explaining the example of installation of the dew condensation prevention pipe of the refrigerator which concerns on Embodiment 1 of this invention. It is the Mollier diagram of isobutane which is the refrigerant | coolant generally used with the refrigerator, and the figure which showed the state transition of the refrigerant | coolant in the refrigerating cycle of the refrigerator which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the opening degree of the decompression device which concerns on Embodiment 1 of this invention, and flow resistance. It is a figure explaining the structure of the refrigerating cycle of the refrigerator which concerns on Embodiment 2 of this invention. It is the table | surface which showed the magnitude relationship of the total refrigerant | coolant flow resistance by the combination of the pressure reduction apparatus of the refrigerator which concerns on Embodiment 2 of this invention, and a three-way valve.

Hereinafter, embodiments of a refrigerator according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.
Refrigerator 100 according to the present embodiment is provided with improvements that enable “stabilization of temperature” and “reduction of power consumption” of the dew condensation prevention pipe embedded in the periphery of the opening of the refrigerator main body. .

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a refrigeration cycle of refrigerator 100 according to Embodiment 1. Based on FIG. 1, the structure of the refrigerating cycle of the refrigerator 100 is demonstrated. The refrigerator 100 cools the inside of the refrigerator 100 to a target temperature using a vapor compression refrigeration cycle.

As shown in FIG. 1, the refrigeration cycle of the refrigerator 100 includes a compressor 11 that compresses and discharges a refrigerant, a condensing pipe 12 that condenses the refrigerant supplied from the compressor 11, and refrigerant that flows out of the condensing pipe 12. A decompression device 18 for decompressing, a dew condensation prevention pipe 13 embedded in the periphery of the opening of the refrigerator body, a dryer 14 connected to the condensation prevention pipe 13, a capillary tube 15 for decompressing the refrigerant flowing out of the dryer 14, The cooler 16 which produces | generates the cool air supplied to each chamber in the refrigerator 100 is connected and comprised by piping.
Further, the refrigeration cycle of the refrigerator 100 is provided with a heat exchange portion 17 for exchanging heat between the refrigerant flowing through the capillary tube 15 and the refrigerant flowing through the pipe (suction pipe) between the cooler 16 and the compressor 11. Yes.

(Compressor 11)
The compressor 11 compresses and discharges the sucked refrigerant. The compressor 11 has a suction side connected to the heat exchange portion 17 and a discharge side connected to the condensing pipe 12. The compressor 11 is arrange | positioned, for example in the machine room provided in the back lower part of the refrigerator 100. FIG. The compressor 11 compresses the refrigerant into a high-temperature and high-pressure refrigerant, is driven by an inverter, and the operation is controlled according to the state in the warehouse.

(Condensation pipe 12)
The condensing pipe 12 is configured to condense and liquefy the refrigerant as the refrigerant discharged from the compressor 11 dissipates heat. One of the condensation pipes 12 is connected to the discharge side of the compressor 11, and the other is connected to the decompression device 18. The condensing pipe 12 is embedded in a hot pipe for drain evaporation, an air-cooled condenser placed in an installation space of the compressor 11, and a heat insulating material on the side and back of the refrigerator.

(Decompression device 18)
The decompression device 18 decompresses the refrigerant that has flowed out of the condensation pipe 12. One of the decompression devices 18 is connected to the condensation pipe 12, and the other is connected to the dew condensation prevention pipe 13. The decompression device 18 according to the first embodiment will be described on the assumption that the refrigerant is decompressed and expanded, and the opening degree can be variably controlled, for example, an electronic expansion valve. As will be described later, the decompression device 18 can be set to two flow resistance values by adjusting the valve opening (see FIG. 4). The decompression device 18 will be described in detail in [about the decompression amount of the decompression device 18] and [detailed configuration and operation of the decompression device 18].

(Condensation prevention pipe 13)
The dew condensation prevention pipe 13 is a pipe which is provided for preventing dew condensation on the front surface portion of the refrigerator main body and acts as a condenser. That is, the dew condensation prevention pipe 13 acts as a condenser and is embedded in the periphery of the opening of the refrigerator body so that the heat of the refrigerant flowing out of the decompression device 18 can be transmitted to the periphery of the opening of the refrigerator body. ing. One of the dew condensation prevention pipes 13 is connected to the decompression device 18 and the other is connected to the dryer 14.
The configuration of the condensation prevention pipe 13 will be described in detail with reference to FIG.

(Dryer 14)
The dryer 14 is configured by a filter for preventing dust, metal powder, and the like in the refrigeration cycle of the refrigerator 100 from flowing into the compressor 11, an adsorbing member that adsorbs moisture in the refrigeration cycle, and the like. One of the dryers 14 is connected to the condensation prevention pipe 13 and the other is connected to the capillary tube 15.

(Capillary tube 15)
The capillary tube 15 acts as a decompression device using the refrigerant flowing out of the dryer 14. One of the capillary tubes 15 is connected to the dryer 14 and the other is connected to the cooler 16. The refrigerant flowing through the capillary tube 15 exchanges heat with the refrigerant flowing through the pipe (suction pipe) between the cooler 16 and the compressor 11 by the action of the heat exchange portion 17.

(Cooler 16)
The cooler 16 generates cool air to be supplied to each room of the refrigerator (see the refrigerator compartment 3 and the like in FIG. 2), and functions as an evaporator. One of the coolers 16 is connected to the capillary tube 15, and the other is connected to the suction side of the compressor 11 via the heat exchange portion 17.
The cooler 16 is provided, for example, in a cooler chamber provided on the back side of the refrigerator 100. A blower fan is provided, for example, above the cooler 16. Air is supplied to the cooler 16 by the blower fan, and cool air cooled around the cooler 16 is supplied to each chamber.

(Heat exchange part 17)
The heat exchanging portion 17 is a portion that exchanges heat between the refrigerant flowing through the capillary tube 15 and the refrigerant sucked into the compressor 11.

Further, for example, a control device 10 including a microcomputer for controlling the operation of the refrigerator 100 is provided on the upper rear surface of the refrigerator 100.

FIG. 2 is a diagram for explaining an installation example of the dew condensation prevention pipe 13 of the refrigerator 100. Based on FIG. 2, the installation example of the dew condensation prevention pipe 13 is demonstrated.

As shown in FIG. 2, the refrigerator 100 includes a box-shaped cabinet portion 21 whose front side is open. The cabinet portion 21 includes an outer box that forms the outer shell of the refrigerator main body and an inner box that forms the inner wall of the refrigerator main body, and a heat insulating material such as urethane is provided therebetween. Further, a divider part (partition wall) 22 that partitions the internal space of the cabinet part 21 into a plurality of storage chambers is provided inside the cabinet part 21. In the refrigerator 100, a refrigerator compartment 3, an ice making compartment 4, a switching compartment 5, a freezer compartment 6, and a vegetable compartment 7 are provided as storage compartments.

The refrigerator compartment 3 is provided in the uppermost part of the refrigerator 100, and the front surface is covered with the double-opening door which has a heat insulation structure so that opening and closing is possible.
The ice making chamber 4 and the switching chamber 5 are provided side by side on the lower side of the refrigeration chamber 3, and the front surfaces of the ice making chamber 4 and the switching chamber 5 are covered with a drawer-type door having a heat insulating structure so as to be freely opened and closed.
The freezing room 6 is provided below the ice making room 4 and the switching room 5, and the front surface is covered with a drawer-type door having a heat insulating structure so as to be opened and closed.
The vegetable compartment 7 is provided below the freezer compartment 6 and at the bottom of the refrigerator 100, and the front surface is covered with a drawer-type door having a heat insulating structure so as to be freely opened and closed.

Each door of the storage room is usually provided with a door open / close sensor (not shown) for detecting the open / closed state. And the control apparatus 10 receives the output from each door opening / closing sensor, detects the open / closed state of each door, for example, when a door remains open for a long time, an operation panel (illustration omitted) or a voice output device Thus, it is possible to notify the user to that effect.

Each storage room is distinguished by a settable temperature zone (set temperature zone). For example, the refrigerator compartment 3 is about 0 ° C. to 4 ° C., the vegetable compartment 7 is about 3 ° C. to 10 ° C., and the ice making room 4 is about The temperature in the freezer compartment 6 can be set to about -16 ° C to -22 ° C.
The switching chamber 5 can be switched to a temperature range such as chilled (about 0 ° C.) or soft freezing (about −7 ° C.). The set temperature of each storage room is not limited to this.

For example, on the surface of the door of the refrigerator compartment 3, there is provided an operation panel composed of an operation switch for adjusting the temperature and setting of each storage room and a liquid crystal for displaying the temperature of each storage room at that time.
The operation panel may be provided with an outside air temperature sensor that detects the temperature of the outside air around the refrigerator 100. The control device 10 controls the operation of the refrigeration cycle and the operation of each part so that the detection value of the internal temperature sensor arranged in each storage room becomes the set temperature set by the operation panel.

Thus, since the inside of the refrigerator 100 is partitioned into a plurality of storage rooms having different temperature zones, the surface temperature of the cabinet unit 21 and the divider unit 22 in which the inside of the refrigerator and the outside of the refrigerator are close to each other is equal to or lower than the outside dew point temperature. If this happens, condensation may occur.
Therefore, in the refrigerator 100, as shown in FIG. 2, the surface temperature of the cabinet part 21 and the divider part 22 is maintained above the dew point of the outside air by the refrigerant condensation heat by the dew condensation prevention pipe 13.

The anti-condensation pipe 13 is bent and installed at the peripheral edge of the front opening of the cabinet portion 21 and the front edge of the divider portion 22. This dew condensation prevention pipe 13 is installed in the cabinet part 21 or the divider part 22 through an elastic member having a large heat capacity such as butyl rubber. As shown in FIG. 2, the dew condensation prevention pipes 13 may be disposed on all front side edges of the cabinet part 21 and the divider part 22.
In addition, the anti-condensation pipe 13 is arranged only on the front side edge of the ice making room 4, the switching room 5, and the freezing room 6 and the front edge of the divider part 22 (the area where the cold air in the freezing temperature zone can leak). You may set up. In addition, arrangement | positioning of the dew condensation prevention pipe 13 is not limited to what was illustrated in FIG. For example, the dew condensation prevention pipe 13 may be arranged at an arbitrary place where dew condensation due to low temperature cold air leaking to the outside can be suppressed.

Here, the rise in the surface temperature of the cabinet part 21 and the divider part 22 and the necessary input of the compressor 11 will be described.
For example, when the surface temperature of the cabinet part 21 or the divider part 22 is raised by the heater instead of the dew condensation prevention pipe 13, if the heater input is increased, the surface temperature of the cabinet part 21 or the divider part 22 rises. When the surface temperature is set to be equal to or higher than the outside air dew point temperature in order to prevent dew condensation on the cabinet part 21 and the divider part 22, if the surface temperature becomes equal to the outside air dew point temperature at a certain heater input Wh, an input exceeding Wh is added. The surface temperature is equal to or higher than the outside air dew point temperature. When the input is less than Wh, the surface temperature is equal to or lower than the outside air dew point temperature. That is, there is a correlation between the heater input and the surface temperature of the cabinet part 21 or the divider part 22, and as the heater input increases, the heater temperature rises and the surface temperature of the cabinet part 21 or the divider part 22 increases.

On the other hand, in the case of the refrigerator 100, the dew condensation prevention pipe 13 plays the same role as the heater, and the heater input is the compressor input. That is, if the surface temperature of the cabinet part 21 or the divider part 22 can be lowered, that is, the temperature of the dew condensation prevention pipe 13 can be lowered, the compressor input is reduced.

FIG. 3 is a Mollier diagram of isobutane, which is a refrigerant generally used in refrigerators, and a diagram showing the state transition of the refrigerant in the refrigeration cycle of the refrigerator 100. A refrigeration cycle of the refrigerator 100 having the decompression device 18 in series between the condensation pipe 12 and the dew condensation prevention pipe 13 will be described with reference to FIG. In addition, the code | symbol in FIG. 3 has shown the same thing as FIG. In FIG. 3, the horizontal axis represents enthalpy and the vertical axis represents pressure. Furthermore, the outside air temperature outside the warehouse is assumed to be 30 (° C.), and the temperature of the air flowing into the cooler 16 is assumed to be −15 (° C.).

The refrigerant in the refrigerator is compressed by the compressor 11 (A → B in FIG. 3) to become a high-temperature and high-pressure refrigerant, and the refrigerant saturation pressure becomes equal to or higher than the outside air temperature. The refrigerant whose refrigerant saturation pressure is equal to or higher than the outside air temperature flows into the condensation pipe 12 and dissipates the heat of condensation to the outside air (B → E in FIG. 3).
The refrigerant that has flowed out of the condensing pipe 12 flows into the decompression device 18 and is depressurized from the refrigerant pressure in the condensing pipe 12 (E → F in FIG. 3). Since the decompression device 18 is provided in the refrigerator 100, the refrigerant pressure in the dew condensation prevention pipe 13 is reduced with respect to the refrigerant pressure in the condensation pipe 12.
The refrigerant that has flowed into the dew condensation prevention pipe 13 condenses in an environment including the inside of the warehouse (F → C in FIG. 3). In addition, "condensation in the environment including the inside of the room" here means that the heat of the dew condensation prevention pipe 13 is transmitted to the outer box and the inner box or the air inside the box forming the outer shell of the refrigerator body, It means that the refrigerant in the dew condensation prevention pipe 13 is condensed.

The refrigerant flowing out from the dew condensation prevention pipe 13 flows into the capillary tube 15 and is depressurized, and also exchanges heat with the refrigerant flowing through the suction pipe of the compressor 11 in the heat exchange portion 17 (C → D in FIG. 3). . Then, the refrigerant flowing out from the capillary tube 15 flows into the cooler 16 and exchanges heat with air supplied to the cooler 16 by a fan (not shown). That is, the refrigerant flowing out from the capillary tube 15 absorbs heat from the air supplied to the cooler 16 and evaporates.
The refrigerant that has absorbed heat and evaporated from the air supplied to the cooler 16 passes through the heat exchange portion 17 and returns to the compressor 11 (D → A in FIG. 3).

[Decompression amount of decompression device 18]
Next, means for reducing the power consumption of the refrigerator 100 will be described. Most of the power consumption of the refrigerator 100 is a compressor input which is an operation source of a vapor compression refrigeration cycle for maintaining the internal temperature.
For example, when the heat insulation performance of the refrigerator to be cooled is high, such as when using a vacuum heat insulating material as a heat insulating material on the side and back of the refrigerator 100, the load for maintaining the internal temperature is small. The required compressor input is reduced. Here, the internal load of the refrigerator 100 includes two loads: “a load resulting from the heat insulation performance of the refrigerator 100” and “an internal load in which condensation heat of the condensation pipe 12 and the dew condensation prevention pipe 13 enters the refrigerator”. There is one.

The condensation pipe 12 is installed on the side surface or the back surface of the refrigerator 100. If the heat insulation performance of the refrigerator 100 is improved as described above, the heat of condensation in the refrigerator can be reduced. On the other hand, as shown in FIG. 2, the condensation prevention pipe 13 is in a position close to the inside of the cabinet and does not have a heat insulation structure with the inside of the cabinet via a heat insulating material or the like. Most of them invade into the warehouse and become a large part of the warehouse load.
As shown in FIG. 3, in the refrigerator 100, the decompression device 18 lowers the refrigerant temperature of the dew condensation prevention pipe 13 with respect to the condensation pipe 12. By reducing the temperature of the dew condensation prevention pipe 13 by the decompression device 18, the temperature difference between the inside temperature and the dew condensation prevention pipe 13 is reduced, and the condensation heat entering the inside from the condensation prevention pipe 13 can be reduced. Thereby, since the load in the refrigerator 100 is reduced and the compressor input is reduced, the power consumption can be reduced.

However, the amount of decompression in the decompression device 18 is up to the saturation pressure at which the refrigerant saturation temperature in the dew condensation prevention pipe 13 is “a temperature 3-5 ° C. lower than the outside air temperature”. Thus, the reason for limiting the amount of pressure reduction in the pressure reducing device 18 is as follows.
In other words, the refrigerant cannot be condensed when the refrigerant saturation pressure in the dew condensation prevention pipe 13 is originally lower than the outside air temperature. However, as shown in FIG. 2, the dew condensation prevention pipe 13 is in a position close to the inside of the compartment, and as a result, is in contact with the inside of the compartment below the outside air temperature. For this reason, the refrigerant can be condensed even if the pressure is reduced to a saturation pressure corresponding to a temperature lower than the outside air temperature. However, the outside air dew point temperature must also be taken into consideration so that the outside air does not condense.

From the above, the amount of decompression in the decompression device 18 during the stable operation of the refrigerator 100 may be “the refrigerant saturation temperature of the dew condensation prevention pipe 13 is equal to or lower than the outside air temperature”. The pressure may be reduced to a saturation pressure of “temperature 3-5 ° C. lower than temperature” or “open-air dew point temperature”. However, in the case of “a temperature 3 to 5 ° C. lower than the outside air temperature”, the amount of decompression in the decompression device 18 is set not to fall below the “outside air dew point temperature” in order to prevent condensation.

[Detailed configuration and operation of decompression device 18]
(About adoption of LEV)
The decompression device 18 may be constituted by a general decompression device mounted on a refrigerator or the like, such as an electronic expansion valve (LEV). This is because the capillary tube has a fixed length and an inner diameter, so that the amount of pressure reduction is fixed, but the LEV can be adjusted to an appropriate opening degree with respect to the target value by using a stepping motor or the like.
In general air-conditioning equipment and refrigeration equipment, the flow resistance is changed by LEV so that the target evaporation temperature (suction temperature) and the target discharge temperature are reached. Therefore, also in the refrigerator 100 according to the first embodiment, as described above, the temperature of the dew condensation prevention pipe 13 is controlled to “outside air dew point temperature” or “temperature 3 to 5 ° C. lower than the outside air temperature”. Is applied to the decompression device 18.
Note that LEV is described in, for example, the document “Refrigeration and Air Conditioning Handbook II”.

The refrigerant flow rate of the refrigerator 100 is about 1 (kg / h) at the time of stable operation with the outside air 30 (° C.). Moreover, in low external air, it is 1 (kg / h) or less. The refrigerant response time τ with respect to the refrigerant control device such as LEV is given by the refrigerant flow rate Gr and the refrigerant amount M of the device as follows.
[Equation 1]
τ = M / Gr (1)
Note that matters such as the equation (1) are described in, for example, the document “Dynamic characteristics and control of refrigeration cycle”.

(About the flow resistance of the decompression device 18)
FIG. 4 is a diagram showing the relationship between the opening degree and the flow resistance of the decompression device 18 according to the first embodiment. The configuration of the decompression device 18 will be described in detail with reference to FIG.
In a general refrigeration equipment such as the refrigerator 100, the refrigerant amount M is approximately 80 (g). From this, the response time τ = 288 (seconds) from the equation (1). In other words, when control is performed using an LEV used in general air conditioning equipment and refrigeration equipment, it takes almost 5 minutes for the refrigerant flow to stabilize for one change in flow resistance. It is that you need.

Here, the “operating time” of the refrigerator 100 is, for example, 30 minutes to 1 hour. The “operation time” refers to the time from when the compressor 11 is started to when it is stopped. That is, the refrigerator 100 repeats a cycle of stopping after being operated for a predetermined time after the compressor 11 is activated, and one period of the cycle is referred to as “operation time”.
Therefore, when the LEV used in general air-conditioning equipment and refrigeration equipment is repeatedly controlled 3 to 6 times, the flow resistance is 5 minutes × 3 to 6 times = 15 to 30 minutes. Necessary for stabilization against changes. That is, more than half of the operation time is necessary for stabilizing the refrigerant flow, and the decompression effect of the decompression device 18 is obtained for the remaining half of the operation time.

Therefore, the decompression device 18 is configured so that the flow resistance of the decompression device 18 has the characteristics shown in FIG. 4 in consideration of the change in the refrigerant flow rate associated with the flow change of the decompression device 18.
That is, in the conventional pressure reducing device, the flow resistance is gradually increased as the opening degree is increased, but the pressure reducing device 18 according to the first embodiment is a compressor input by the pressure reducing effect. In order to obtain the reduction effect as much as possible, it is configured to have two regions of a large resistance (first flow resistance) and a small resistance (second flow resistance). The decompression device 18 is configured to be adjustable in two stages of a first flow resistance and a second flow resistance having a smaller flow resistance than the first flow resistance.
Further, the adjustable opening range of the decompression device 18 includes an opening A as an opening when the resistance is large, an opening C as an opening when the resistance is small, and a large resistance and a small resistance. An opening B is provided as an opening when switching between the two.

(About operation of decompression device 18)
An operation method of the decompression device 18 will be described.
In the stable operation of the refrigerator 100, the decompression device 18 is adjusted to the opening degree (opening degree A) in the region of large resistance in order to obtain the decompression effect of the decompression device 18 in all of the “operation time”. At the opening degree A, the opening degree of the decompression device 18 is reduced, the flow resistance in the decompression device 18 is large, and the refrigerant flow rate of the decompression device 18 is small.
In this way, during stable operation where it is not necessary to circulate a large amount of refrigerant, the decompression device 18 is throttled to an opening A, and the refrigerant temperature of the dew condensation prevention pipe 13 is lowered relative to the condensation pipe 12. As a result, the temperature difference between the internal temperature and the dew condensation prevention pipe 13 is reduced, and the condensation heat entering the inside from the dew condensation prevention pipe 13 can be reduced. And the load in the refrigerator 100 can be reduced, the compressor input can be reduced, and the power consumption can be reduced.

On the other hand, the decompression device 18 is adjusted to the opening degree (opening degree C) of the region having a small resistance during a transient operation such as when the door is opened or closed, when the door is started, or after the defrosting operation is completed. At the opening degree C, the opening degree of the decompression device 18 is increased, the flow resistance in the decompression device 18 is small, and the refrigerant flow rate of the decompression device 18 is large.
During transient operation, the internal load cannot be clearly defined (for example, the internal temperature changes with time), so the effect of reducing the refrigerant pressure in the dew condensation prevention pipe 13 relative to the refrigerant pressure in the condensation pipe 12 cannot be obtained. it is conceivable that. For this reason, the flow resistance of the decompression device 18 is made as small as possible, and the refrigerant pressure loss in the condenser including the condensation pipe 12 and the dew condensation prevention pipe 13 is reduced.

Further, as shown in FIG. 4, the decompression device 18 divides large resistance and small resistance with the opening B as a boundary. However, the decompression device 18 is used to ensure manufacturing variation and a control range of the decompression device 18. It is desirable to use the opening B at a position that is approximately half of the total opening. In other words, the pressure reducing device 18 has a small resistance when it is larger than the substantially middle opening of the entire opening range of the decompressing device 18, and when it is smaller than the substantially middle opening of the entire opening range of the decompressing device 18, It is desirable that the resistance is increased.
In addition, as shown in FIG. 4, you may have a small inclination in a high resistance area | region and a low resistance area | region. That is, there is no problem even if the flow resistance value slightly changes by changing the opening degree in the high resistance region and the low resistance region.
Further, the flow resistance value when the pressure reducing device 18 has a small resistance is preferably as small as described above, and the flow resistance value when the resistance is large is, for example, at the outside air 30 (° C.), the dew condensation prevention pipe 13. It is good to set it as the resistance value set so that the inside refrigerant | coolant saturation temperature may become target temperature.

In the first embodiment, the case where the flow resistance is a LEV having two regions of a large resistance and a small resistance has been described as an example of the decompression device 18, but the present invention is not limited thereto. For example, a plurality of capillary tubes may be installed and the flow resistance may be changed by a switching valve. However, in consideration of the internal volume of the refrigerator 100 and the necessary material cost, it is desirable to employ a decompression device 18 having two types of flow resistances, a large resistance and a small resistance, as in the first embodiment.

[Effects of refrigerator 100 according to Embodiment 1]
In the refrigerator 100 according to the first embodiment, since the decompression device 18 has two regions of high resistance and low resistance, the response time until the target temperature is reached becomes long even in a refrigerator with a small refrigerant flow rate. And the temperature of the dew condensation prevention pipe 13 can be stabilized.

In the refrigerator 100 according to the first embodiment, the decompression device 18 is provided between the condensation pipe 12 and the condensation prevention pipe 13, and the refrigerant temperature of the condensation prevention pipe 13 is set to the condensation pipe 12 by the decompression device 18. It is decreasing. As a result, the temperature difference between the internal temperature and the dew condensation prevention pipe 13 is reduced, and the condensation heat entering the interior from the dew condensation prevention pipe 13 is reduced, so that the compressor input is reduced and the power consumption is reduced. it can.

Embodiment 2. FIG.
FIG. 5 is a diagram illustrating the configuration of the refrigeration cycle of refrigerator 100A according to Embodiment 2 of the present invention. Based on FIG. 5, the structure of the refrigerating cycle of refrigerator 100A is demonstrated. Similarly to the refrigerator 100 according to the first embodiment, the refrigerator 100 cools the inside of the refrigerator 100A to the target temperature using a vapor compression refrigeration cycle. In the second embodiment, the difference from the first embodiment described above will be mainly described, and parts having the same functions as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted. And

In the refrigerator 100 according to the first embodiment, the refrigeration cycle in which one capillary tube 15 is connected has been described as an example. In the refrigerator 100A according to the second embodiment, as shown in FIG. A refrigeration cycle to which tubes (capillary tube 52 and capillary tube 53) are connected is provided. A three-way valve 54 as a flow path changing device for switching the refrigerant flow path is provided on the upstream side of the capillary tube 52 and the capillary tube 53. Other configurations of the refrigerator 100A are the same as those of the refrigerator 100 according to the first embodiment.

∙ Two capillary tubes with different flow resistances are used. Here, it is assumed that the capillary tube 52 has a relatively small flow resistance (that is, a large inner diameter), and the capillary tube 53 has a relatively large flow resistance (that is, a small inner diameter). ing. Note that there is no problem even if the flow resistances of the capillary tube 52 and the capillary tube 53 are reversed.

The three-way valve 54 is not only changed to a refrigerant flow path for flowing refrigerant to the capillary tube 52 or a refrigerant flow path for flowing refrigerant to the capillary tube 53, but also a refrigerant flow for flowing refrigerant to both the capillary tube 52 and the capillary tube 53. It can be changed to a road. The three-way valve 54 changes the refrigerant flow path according to the necessary refrigerant flow rate of the refrigerator 100A. Specifically, the controller 10 that has determined the necessary refrigerant flow rate controls the three-way valve 54, whereby the refrigerant flow path through which the refrigerant flows is changed. Although the three-way valve 54 is described as an example of the flow path changing device, the flow path changing device is not limited to the three-way valve 54. For example, a flow path changing device may be configured by combining two-way valves, or a flow path changing device may be configured using a four-way valve.

Next, the operation of the refrigerator 100A will be described.
In the refrigerator 100 </ b> A, the refrigerant flow path is determined by controlling the frequency of the compressor 11, the opening degree of the decompression device 18, and the flow path changing device in accordance with the required refrigerant flow rate. ing. That is, the refrigerator 100A individually controls each of the compressor 11, the pressure reducing device 18, and the flow path changing device according to the refrigerant flow rate.

For example, when increasing the refrigerant flow rate, the control device 10 increases the frequency of the compressor 11 and simultaneously causes the three-way valve 54 to flow the refrigerant to the capillary tube 52 or to both the capillary tube 52 and the capillary tube 53. Select the refrigerant flow path.
On the other hand, when decreasing the refrigerant flow rate, the control device 10 selects the refrigerant flow path for flowing the refrigerant through the capillary tube 53 by the three-way valve 54 at the same time as reducing the frequency of the compressor 11.

However, the number of rotations of the compressor 11, the refrigerant flow path (the refrigerant flow path for flowing the refrigerant through the capillary tube 52, the refrigerant flow path for flowing the refrigerant through the capillary tube 53, the refrigerant that flows the refrigerant through both the capillary tube 52 and the capillary tube 53) If the selection of the flow path) does not match the relationship with the amount of supplied refrigerant, an abnormality such as a low pressure pull-in occurs.

If it is the conventional refrigerator which does not have the decompression device 18, the selection of the frequency of the compressor 11 and the refrigerant | coolant flow path should just be matched as mentioned above, but in the refrigerator 100A, the refrigerant | coolant flow upstream of the three-way valve 54 is sufficient. A decompressor 18 is included. As described in the first embodiment, the decompression device 18 changes to the opening degree A when the resistance is large and the opening degree C where the resistance is small according to the internal load. For this reason, it is necessary to adjust the selection of the refrigerant flow path including not only the frequency of the compressor 11 but also the opening of the decompression device 18. This is because the total refrigerant flow resistance in the refrigerant circuit is the sum of the resistance of the decompression device 18 and the resistance of the capillary tubes (capillary tube 52, capillary tube 53).

FIG. 6 is a table showing the magnitude relationship of the total refrigerant flow resistance by the combination of the pressure reducing device 18 and the three-way valve 54. In FIG. 6, “H” → “M (M1, M2)” → “L” is indicated from the combination having a large refrigerant flow resistance. The operation of the refrigerator 100A will be described with reference to FIG. Although the basic operation is as described above, since the refrigerator 100A includes the decompression device 18, the operation is as follows. The difference between “M1” and “M2” will be described later.

When increasing the refrigerant flow rate, the control device 10 increases (increases) the frequency of the compressor 11 and simultaneously selects the combination of the decompression device 18 and the three-way valve 54 as “L” in FIG. 6. Specifically, when “L” is selected, the decompression device 18 is controlled to the opening degree C, and the three-way valve 54 is controlled so that the refrigerant flows through both the capillary tube 52 and the capillary tube 53. The

When reducing the refrigerant flow rate, the control device 10 lowers (decreases) the frequency of the compressor 11 and simultaneously selects the combination of the decompression device 18 and the three-way valve 54 as “H” in FIG. 6. When “H” is selected, specifically, the decompression device 18 is controlled to the opening degree A, and the three-way valve 54 is controlled so that the refrigerant flows through the capillary tube 53 in the refrigerant flow path.
However, when the frequency reduction amount of the compressor 11 and the total refrigerant flow resistance “H” do not match (for example, when the low pressure is reduced and the refrigerant is depleted (SH) in the cooler 16), the pressure is reduced. The combination of the device 18 and the three-way valve 54 is changed from “H” to “M” in FIG.

Here, the difference between “M1” and “M2” will be described.
In “M1”, the resistance value of the decompression device 18 is reduced. Therefore, the saturation pressures of the condensation pipe 12 and the dew condensation prevention pipe 13 are substantially equal, and the refrigerant temperature of the dew condensation prevention pipe 13 is maintained at or above the outside air temperature as shown in the first embodiment. Therefore, when the outside air humidity is high or when condensation is avoided (for example, when the internal temperature is set lower than usual), “M1” is selected. When “M1” is selected, specifically, the decompression device 18 is controlled to the opening degree C, and the three-way valve 54 is controlled so that the refrigerant flows through the capillary tube 53 or the capillary tube 52 in the refrigerant flow path.

On the other hand, in “M2”, the resistance value of the decompression device 18 is set large. Therefore, as shown in the first embodiment, although depending on the resistance value of the opening A, the refrigerant saturation temperature in the dew condensation prevention pipe 13 becomes a saturation pressure of “a temperature 3 to 5 ° C. lower than the outside air temperature”. . As shown in the first embodiment, the refrigerant saturation temperature in the dew condensation prevention pipe 13 becomes “a temperature 3 to 5 ° C. lower than the outside air temperature”, thereby reducing the internal load of the refrigerator 100A and reducing the compressor input. The power consumption can be reduced. Therefore, when reducing the power consumption, “M2” is selected. When “M2” is selected, specifically, the decompression device 18 is controlled to an opening A, and the refrigerant flow path is a three-way valve so that the refrigerant flows through the capillary tube 52 or both the capillary tube 52 and the capillary tube 53. 54 is controlled.

[Effects of Refrigerator 100A according to Embodiment 2]
The refrigerator 100A according to the second embodiment is provided with two capillary tubes and a flow path changing device in addition to the effect of the refrigerator 100 according to the first embodiment, and adjusts the selection between the decompression device 18 and the refrigerant flow path. By doing, it can be set as the flow resistance suitable for a refrigerant | coolant flow volume.

1 cold storage room, 3 cold storage room, 4 ice making room, 5 switching room, 6 freezing room, 7 vegetable room, 10 control device, 11 compressor, 12 condensation pipe, 13 condensation prevention pipe, 14 dryer, 15 capillary tube, 16 cooling 17 heat exchanger, 18 decompressor, 21 cabinet, 22 divider, 52 capillary tube, 53 capillary tube, 54 three-way valve, 100 refrigerator, 100A refrigerator.

Claims

In a refrigerator having a refrigeration cycle in which a compressor, a condensation pipe, a decompression device, a dew condensation prevention pipe, a capillary tube, and a cooler are connected in this order,
The decompressor is
The flow resistance of the refrigerant,
A refrigerator configured to be adjustable in two stages of a first flow resistance and a second flow resistance smaller than the first flow resistance.
When the refrigerator is in stable operation, the first flow resistance is
When the refrigerator is in a transient operation, the second flow resistance is
The refrigerator according to claim 1, wherein the refrigerator is used.
The first flow resistance is:
2. The refrigerator according to claim 1, wherein the refrigerant saturation temperature of the dew condensation prevention pipe is set to a saturation pressure that is lower than the outside air temperature by a predetermined temperature during the stable operation.
The first flow resistance is:
2. The refrigerator according to claim 1, wherein the refrigerant saturation temperature of the dew condensation prevention pipe is set to a saturation pressure that is substantially the same as the outside air temperature during stable operation.
The second flow resistance is
The refrigerator according to any one of claims 1 to 4, wherein the refrigerator is set based on a refrigerant pressure loss between the condensing pipe and the dew condensation prevention pipe during a transient operation of the refrigerator.
The first flow resistance is:
It is set at an opening smaller than a substantially intermediate opening of the entire opening range of the decompression device,
The second flow resistance is
The refrigerator according to any one of claims 1 to 5, wherein the refrigerator is set to an opening larger than the substantially intermediate opening of the entire opening range of the decompression device.
The decompressor is
The refrigerator according to any one of claims 1 to 6, wherein the refrigerator is configured by an electronic expansion valve.
The decompressor is
The refrigerator according to any one of claims 1 to 7, comprising a capillary tube for depressurizing the refrigerant and a switching valve for switching a flow of the refrigerant.
The capillary tube is composed of two capillary tubes having different flow resistances, provided on the upstream side of the capillary tube, and a refrigerant flow path for flowing a refrigerant to one of the capillary tubes, or a refrigerant for both the capillary tubes Provided with a flow path changing device for changing to a refrigerant flow path flowing through
The refrigerator according to any one of claims 1 to 8, wherein each of the compressor, the pressure reducing device, and the flow path changing device is individually controlled according to a refrigerant flow rate.
When increasing the refrigerant flow rate,
The frequency of the compressor is increased, the flow resistance of the decompression device is decreased, and either the capillary tube having the smaller flow resistance or the two capillary tubes is selected by the flow path changing device. The refrigerator according to claim 9.
When reducing the coolant flow rate,
The refrigerator according to claim 9, wherein the frequency of the compressor is decreased, the flow resistance of the decompression device is increased, and the capillary tube having the larger flow resistance is selected by the flow path changing device.
When the outside air humidity is high or when condensation is avoided,
The refrigerator according to claim 9, wherein the flow resistance of the decompression device is reduced, and the capillary tube having the larger flow resistance is selected by the flow path changing device.
When reducing power consumption,
The flow resistance of the decompression device is increased, and the capillary tube with the smaller flow resistance is selected by the flow path changing device.