WO2006087840A1

WO2006087840A1 - Refrigerator

Info

Publication number: WO2006087840A1
Application number: PCT/JP2005/016912
Authority: WO
Inventors: Satoshi Miyamoto; Hiroshi Tatsumi; Wei Chen; Mizuho Fukaya; Junji Miyakami
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-02-17
Filing date: 2005-09-14
Publication date: 2006-08-24
Also published as: US20080155994A1; KR20070103504A; EP1852665A1; CN101120215A

Abstract

A refrigerator so designed that its inside is cooled by a Stirling refrigerating engine, comprising a state detection means (S01) detecting the supercooling critical state of the Stirling refrigerating engine and a supercooling prevention means (S02) preventing the Stirling refrigerating engine from being supercooled based on the detection of the supercooling critical state by the state detection means. Thus, the Stirling refrigerating engine can be prevented from being supercooled.

Description

Specification

Refrigerator

Technical field

TECHNICAL FIELD [0001] The present invention relates to a refrigerator, and more particularly to a refrigerator that cools the interior of a refrigerator with a Stirling refrigeration engine.

Background art

[0002] In recent years, the adverse effects of chlorofluorocarbons on the global environment have been pointed out, and V-types that do not use chlorofluorocarbons, and those equipped with a Stirling refrigeration engine as a refrigerator are attracting attention. In this refrigerator, the cold heat of the cold head of the Stirling refrigeration engine is transmitted to the low-temperature evaporator via the secondary refrigerant, and the cold air generated by the low-temperature evaporator is supplied into the refrigerator (for example, JP 2002-221384 A (see Patent Document 1).

Patent Document 1: JP 2002-221384 A

Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the conventional cooling device, when the cooling capacity of the Stirling refrigeration engine is large, the secondary refrigerant freezes and the cold heat of the cold head of the Stirling refrigeration engine is not transmitted to the low-temperature side evaporator, There is a problem that it will not be cooled.

[0004] Further, the Stirling refrigeration engine has a characteristic that the output cannot be increased when the cold head is at a high temperature. For this reason, it is desirable to cool the inside of the refrigerator rapidly even when the cold head is at a high temperature, for example, when the refrigerator is turned on or when the quick freezing operation mode is switched.

[0005] The present invention was made to solve the above-described problems, and one of the objects of the present invention is that the Stirling refrigeration engine is overcooled before the Stirling refrigeration engine is overcooled. It is to provide a refrigerator that can be prevented.

[0006] Another object of the present invention is to provide a refrigerator having improved efficiency for cooling the interior of the refrigerator.

Means for solving the problem [0007] In order to achieve the above-described object, according to one aspect of the present invention, the refrigerator is a refrigerator that cools the interior of the refrigerator with a Stirling refrigeration engine, and detects an overcooled state of the Stirling refrigeration engine. And a supercooling prevention unit that prevents the Stirling refrigeration engine from being overcooled based on the detection of the overcooled state by the state detection unit.

[0008] According to the present invention, it is possible to provide a refrigerator capable of avoiding that the Stirling refrigeration engine is overcooled before the Stirling refrigeration engine is overcooled.

[0009] Preferably, a door state detection unit that detects an open / closed state of a door provided in a cooling chamber of the refrigerator, a cooling fan that supplies cold air cooled by a Stirling refrigeration engine, and a door state detection unit And a cooling fan control unit that stops the cooling fan while the door is detected to be open, and the state detection unit detects that the door has been opened for a predetermined time by the door state detection unit. To detect.

According to the present invention, it is detected that the door has been opened for a predetermined time. Since the cooling fan stops while the door is open, the air around the cooler cooler stagnates during that time. For this reason, if the Stirling refrigeration engine continues to drive, the temperature of the secondary refrigerant will decrease. For this reason, the state just before the secondary refrigerant freezes can be detected based on the time when the cooling fan is stopped.

[0011] Preferably, the refrigerator includes a first cooling chamber and a second cooling chamber, each of which is partitioned by a heat insulating material and has an opening / closing door, and the cooling fan receives cold air cooled by a Stirling refrigeration engine. Supplying air to the first cooling chamber and guiding the air cooled by the Stirling refrigeration engine to the second cooling chamber, and the cooling air provided in the air passage and cooled by the Stirling refrigeration engine is shut off And a blower fan that blows cool air cooled by the Stirling refrigeration engine to the air passage, and the overcooling prevention unit is configured to detect whether the door of the first cooling chamber is closed by the door state detection unit. When the opening state of the second cooling chamber door is detected, the air blocking passage is blocked by the blocking section and the cooling fan is released and driven, and the door state detecting section opens the first cooling chamber door. If the closed state of the door of the state and the second cold 却室 is detected, it drives the blower fan together when to release the blocking of the air passage to the blocking portion. [0012] According to the present invention, when the closed state of the first cooling chamber door and the open state of the second cooling chamber door are detected, the air passage is blocked and the cooling fan is driven, When the open state of the cooling chamber door 1 and the closed state of the second cooling chamber door are detected, the air passage is unblocked and the blower fan is driven. Therefore, when the second cooling chamber door is opened with the first cooling chamber door closed, the air cooled by the Stirling refrigeration engine is supplied to the first cooling chamber. When the door of the first cooling chamber is opened while the door of the second cooling chamber is closed, the air cooled by the Stirling refrigeration engine is supplied to the second cooling chamber. Regardless of whether the first door or the second door is opened, the air cooled by the Stirling refrigeration engine is convected, so that the Stirling refrigeration engine can be prevented from being overcooled. In addition, since the cool air sent to the cooling chamber with the door open can be reduced, it is possible to prevent the cool air inside the cabinet from leaking outside.

[0013] Preferably, the refrigerator further includes a low temperature side evaporator that receives cold heat from a low temperature portion formed in the Stirling refrigeration engine via a secondary refrigerant. The state detection unit is a low-temperature part, a low-temperature side evaporator or a low-temperature side condenser that is paired with a low-temperature side evaporator (secondary refrigerant circulation that circulates secondary refrigerant between the low-temperature side evaporator and the low-temperature side condenser) A temperature detection unit for detecting the temperature of the circuit), and detects that the temperature detected by the temperature detection unit has fallen below a predetermined temperature.

According to the present invention, it is detected that the temperature of the low temperature part and the secondary refrigerant circulation circuit (typically, the low temperature side evaporator or the low temperature side condenser) is below a predetermined temperature. For this reason, it can be detected that the Stirling refrigeration engine is supercooled.

[0015] Preferably, the anti-freezing unit is a control different from the stop control and performs a supercooling for preventing the Stirling refrigeration engine from being overcooled before performing the stop control for controlling and stopping the Stirling refrigeration engine. Perform prevention control.

[0016] According to the present invention, the Stirling refrigeration engine is controlled by performing the supercooling prevention control different from the stop control before performing the stop control for stopping the Stirling refrigeration engine in order to prevent the Stirling refrigeration engine from being overcooled. Prevent the engine from overcooling. For this reason, the Stirling refrigeration engine is overcooled by the supercooling prevention control. If this can be prevented, it is not necessary to perform stop control of the Stirling refrigeration engine. As a result, it is possible to prevent the Stirling refrigeration engine from being stopped as much as possible. Thereby, the reliability of a refrigerator can be improved.

[0017] Preferably, the predetermined temperature is a first temperature that is higher than a temperature at which the Stirling refrigeration engine is supercooled, and a second temperature that is higher than the temperature at which the Stirling refrigeration engine is supercooled and lower than the first temperature. The supercooling prevention unit performs supercooling prevention control when the state detection unit detects that the temperature is below the first temperature, and further, the state detection unit sets the second temperature. Stop control is performed when it is detected that the value has fallen below.

[0018] According to the present invention, first, the supercooling prevention control is performed when the temperature is lower than the first temperature higher than the temperature at which the Stirling refrigeration engine is supercooled, and the Stirling refrigeration engine is further supercooled. Stop control is performed when the temperature falls below a second temperature that is higher than the temperature and lower than the first temperature. Therefore, if the supercooling prevention control can prevent the Stirling refrigeration engine from being overcooled without falling below the second temperature, the Stirling refrigeration engine stop control need not be performed. As a result, the Stirling freezing engine can be stopped as much as possible.

[0019] Preferably, the apparatus further includes a temperature detection abnormality detection unit that detects an abnormality in temperature detection by the temperature detection unit when the temperature detection unit detects the temperature.

[0020] According to the present invention, since temperature detection abnormality is detected when temperature is detected, erroneous detection of temperature can be prevented. For this reason, the Stirling refrigeration engine can be prevented from being stopped based on the erroneous detection that the temperature is lower than the predetermined temperature.

[0021] Preferably, a cooling fan that supplies cold air cooled by the low-temperature side evaporator to the interior is further provided, and the overcooling prevention unit drives the cooling fan or increases the air volume of the cooling fan.

According to the present invention, the cooling fan is driven or the air volume of the cooling fan is increased, so that air around the low-temperature side evaporator is convected. For this reason, since the air newly sent to the low temperature side evaporator gives heat to the secondary refrigerant, the temperature of the secondary refrigerant rises. As a result, the Stirling refrigeration engine can be prevented from being overcooled. In addition, since the air in the cabinet is convected by the cooling fan, the air in the cabinet is driven by the Stirling refrigeration engine. Can be efficiently cooled. As a result, the COP (Coef ficient Of Performance, coefficient of performance) of the Stirling refrigeration engine can be improved.

[0023] Preferably, the overcooling prevention unit drives the cooling fan or increases the air volume of the cooling fan when it is detected by the state detection unit that the temperature is lower than the first temperature. The cooling power is controlled by controlling the Stirling refrigeration engine when the condition detection unit detects that the temperature has dropped below the first temperature after a predetermined time has elapsed by driving the rejection fan or increasing the air volume of the cooling fan. Reduce.

[0024] According to the present invention, when the temperature of the secondary refrigerant does not increase and is lower than the first temperature even though heat is given to the secondary refrigerant, the Stirling refrigeration engine Control to reduce the cooling capacity. For this reason, since the cooling of the secondary refrigerant is suppressed, the temperature of the secondary refrigerant rises. As a result, the Stirling refrigeration engine can be prevented from being overcooled.

[0025] Preferably, the supercooling prevention unit includes a rotation speed control unit that controls the rotation speed of the cooling fan, and the supercooling prevention unit is detected by the state detection unit to have fallen below the first temperature. When the cooling fan is driven with the rotational speed of the cooling fan being maximized and the cooling fan is driven with the rotational speed of the cooling fan being maximized with the rotational capacity of the cooling fan. When the detection unit detects that the temperature is lower than the first temperature, the Stirling refrigeration engine is controlled to reduce the cooling capacity.

[0026] According to the present invention, since the cooling fan is driven with the maximum rotational speed, the Stirling refrigeration engine is overcooled compared to when the rotational speed is not maximum. More can be prevented. In addition, since the air in the cabinet is further convected by the cooling fan by maximizing the rotation speed, the COP of the Stirling refrigeration engine can be further improved.

[0027] If the temperature of the secondary refrigerant does not increase and is lower than the first temperature even though heat is given to the secondary refrigerant, the cooling capacity of the Stirling refrigeration engine is reduced. Control so that For this reason, since the cooling of the secondary refrigerant is suppressed, the temperature of the secondary refrigerant rises. As a result, the Stirling refrigeration engine can be prevented from being overcooled. This anti-freezing control is preferably performed when the door is closed. The door If the cooling fan is driven or the air flow of the cooling fan is increased in the open state, the air in the cabinet leaks to the outside, and then the door is closed when the door is closed. They need to increase the cooling capacity of the Stirling refrigeration engine to cool the air again.

Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view showing an embodiment of a refrigerator according to the present invention.

FIG. 2 is a diagram schematically showing the flow of cool air in a refrigerator in the present embodiment.

FIG. 3 is a functional block diagram showing a freeze prevention function of the refrigerator in the first embodiment.

FIG. 4 is a flowchart showing the flow of anti-freezing processing executed in the refrigerator in the first embodiment.

FIG. 5 is a flowchart showing a flow of a modified anti-freezing process executed in the refrigerator in the first embodiment.

FIG. 6 is a functional block diagram showing a freeze prevention function of the refrigerator in the second embodiment.

FIG. 7 is a flowchart showing a flow of anti-freezing processing executed in the refrigerator in the second embodiment.

FIG. 8 is a flowchart showing a flow of a modified anti-freezing process executed in the refrigerator in the second embodiment.

FIG. 9 is a functional block diagram showing a freeze prevention function of the refrigerator in the third embodiment.

FIG. 10 is a flowchart showing a flow of anti-freezing processing executed in the refrigerator in the third embodiment. Explanation of symbols

[0029] 1 refrigerator, 2 cooling fans, 10 housing, 11 second cooling chamber, 12 first cooling chamber, 14 upper door, 15 lower door, 17 packing, 18 shelves, 19 machine room, 20, 21 duct 20A, 20B Cold air outlet, 22 Cooling fan, 30 Stirling refrigeration engine, 40 Low temperature side circulation circuit, 41 Low temperature side condenser, 42 Low temperature side evaporator, 50 High temperature side natural circulation circuit , 51 High-temperature side evaporator, 52 High-temperature side condenser, 61 Damper, 62 Blower, 81 Temperature sensor, 82 Upper door open / close detection switch, 83 Lower door open / close detection switch, 84 Door open / close detection switch, 90 Control unit, 91 Display Department.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, I won't repeat the detailed explanation!

[0031] <First embodiment>

FIG. 1 is a schematic cross-sectional view showing an embodiment of a refrigerator according to the present invention. FIG. 2 is a diagram schematically showing the flow of cool air in the refrigerator in the present embodiment. With reference to FIG. 1 and FIG. 2, the refrigerator 1 is for food preservation and includes a housing 10 having a heat insulating structure. Inside the housing 10, cooling chambers 11 and 12 are provided that are partitioned into two upper and lower stages. Each of the cooling chambers 11 and 12 has an opening on the front side (left side in FIG. 1) of the housing 10, and the opening is closed by an openable and closable upper door 14 and lower door 15. The upper door 14 and the lower door 15 include a heat insulating material, and packings 17 each having a shape surrounding the openings of the cooling chambers 11 and 12 are mounted on the back surfaces thereof. Inside the cooling chambers 11 and 12, shelves 18 suitable for the type of food to be stored are installed as appropriate.

[0032] A cooling system and a heat dissipation system having a Stirling refrigeration engine 30 as a central element are disposed from the upper surface to the rear surface and further to the lower surface of the housing 10. A machine room 19 is provided at one corner of the upper and rear surfaces of the housing 10, and the Stirling refrigeration engine 30 is installed in the machine room 19.

A part of the Stirling refrigerating engine 30 forms a low temperature part (hereinafter referred to as a cold head) when driven. A low temperature side condenser 41 is attached to the cold head. In the back of the cooling chamber 12, a low-temperature evaporator 42 is installed. The low temperature side condenser 41 and the low temperature side evaporator 42 are connected via a refrigerant pipe, and a low temperature side circulation circuit (secondary refrigerant circulation circuit) 40 is configured by both. The low-temperature side circulation circuit 40 contains natural refrigerant such as CO.

2

It is enclosed and heat is transferred by the low-temperature side evaporator 42 and the low-temperature side condenser 41. [0034] Inside the housing 10, ducts 20 and 21 are provided for distributing the cold air obtained by the low temperature side evaporator 42 to the cooling chambers 11 and 12. The duct 20 has a cooling air outlet (first cooling chamber) 12 having a cold air outlet 20A communicating therewith in a proper position. A cooling fan 22 is installed in the duct 20 at an appropriate place. The cooling fan 22 forcibly sends the cool air in the duct 20 to the cooling chamber 12. Further, when the cooling fan 22 is driven, the air around the low temperature side evaporator 42 is convected. As a result, another air having a relatively high temperature is supplied to the low temperature side evaporator 42.

The duct 21 has a cold air outlet 21 A communicating with the cooling chamber (second cooling chamber) 11 at an appropriate place. A blower fan 62 is installed in the duct 21 at an appropriate place. The blower fan 62 blows air to the data 21 and forcibly sends the cool air in the duct 21 to the cooling chamber 11. In addition, an openable / closable damper 61 is installed at one end of the duct 21 on the low temperature side evaporator 42 side. When the damper 61 is closed, the duct 21 and the duct 20 are separated. Therefore, the cold air in the duct 20 is blocked by the damper 61 and is prevented from moving into the duct 21. When the damper 61 is open, the duct 21 and the duct 20 communicate with each other. Therefore, when the blower fan 62 is driven with the damper 61 open, the cold air in the duct 20 flows into the duct 21 and the cold air is forcibly sent to the cooling chamber 11.

In the state where the damper 61 is opened, it is possible to drive the blower fan 62 without driving the cooling fan 22. Even in this state, the cold air in the duct 20 flows into the duct 21, and the cold air is forced into the cooling chamber 11. Further, when the blower fan 62 is driven, the air around the low temperature side evaporator 42 is convected. As a result, the low temperature side evaporator 42 is supplied with a relatively high temperature and another air.

[0037] Further, when the damper 61 is open, the cooling fan 22 and the blower fan 62 can be driven. In this state, the cool air in the duct 20 may be sent to the cooling chamber 12 by the cooling fan 22, or may be sent to the cooling chamber 11 via the duct 21 by the blower fan 62. Even in this case, the air around the low temperature side evaporator 42 is convected, and another air having a relatively high temperature is supplied to the low temperature side evaporator 42.

Although not shown in the figure, a duct for collecting air from the cooling chambers 11 and 12 is also provided inside the housing 10. The duct has a blower outlet below the low-temperature evaporator 42. Then, the air to be cooled is supplied to the low temperature side evaporator 42 as indicated by the broken line arrow in FIG.

[0039] The other part of the Stirling refrigerating engine 30 forms a worm head (high temperature part) when driven. A high temperature side evaporator 51 is attached to the worm head. Further, on the upper surface of the housing 10, a high-temperature side condenser 52 and a blower fan 53 for dissipating heat to the outside environment are provided. The high temperature side evaporator 51 and the high temperature side condenser 52 are connected via a refrigerant pipe, and a high temperature side natural circulation circuit 50 is configured by both. The high temperature side natural circulation circuit 50 is sealed with water (including an aqueous solution) or a hydrocarbon-based natural refrigerant, and the refrigerant naturally circulates in the high temperature side natural circulation circuit 50.

[0040] Next, the operation of the refrigerator 1 having the above-described structural force will be described. When the Stirling refrigeration engine 30 is driven in the refrigerator 1 having the above-described configuration, the temperature of the cold head decreases. Therefore, the low temperature side condenser 41 is cooled, and the internal secondary refrigerant (hereinafter abbreviated as refrigerant) is condensed.

[0041] The refrigerant condensed in the low temperature side condenser 41 flows into the low temperature side evaporator 42 through the low temperature side circulation circuit 40. The refrigerant flowing into the low temperature side evaporator 42 is evaporated by the heat of the airflow passing outside the low temperature side evaporator 42 and the surface temperature of the low temperature side evaporator 42 is lowered. Therefore, the air passing through the low-temperature side evaporator 42 becomes cold air, and is blown out from the cold air outlet 20A of the duct 20 to the cooling chamber 11 and blown out to the cold air outlet 21A of the duct 21. Thereby, the temperature of the cooling chambers 11 and 12 is lowered. Thereafter, the air in the cooling chambers 11 and 12 returns to the low-temperature evaporator 42 through a duct (not shown).

It should be noted that the refrigerant evaporated in the low temperature side evaporator 42 passes through the low temperature side circulation circuit 40 and returns to the low temperature side condenser 41, where it is deprived of heat and condensed again. Then, the heat exchange operation described above is repeated.

On the other hand, the heat generated by driving the Stirling refrigeration engine 30 and the heat recovered from the interior by the cold head are radiated from the worm head as exhaust heat. Therefore, the high temperature side evaporator 51 is heated and the internal refrigerant evaporates.

[0044] The gas phase refrigerant generated in the high temperature side evaporator 51 flows through the high temperature side natural circulation circuit 50 into the high temperature side condenser 52 provided above. The refrigerant that has flowed into the high-temperature side condenser 52 is converted into an airflow introduced into the high-temperature side condenser 52 from the outside by the blower fan 53. Therefore, it is deprived of heat and condensed. The refrigerant condensed in the high temperature side condenser 52 returns to the high temperature side evaporator 51 through the high temperature side natural circulation circuit 50, where it receives heat and evaporates again. Then, the heat exchange operation described above is repeated.

FIG. 3 is a functional block diagram showing the freeze prevention function of the refrigerator in the first embodiment. Referring to FIG. 3, the refrigerator 1 includes a control unit 90 for controlling the entire refrigerator, and a temperature sensor 81 connected thereto. The control unit 90 is connected to the Stirling refrigeration engine 30, the cooling P fan 22, the damper 61, and the blower fan 62.

[0046] The temperature sensor 81 detects the temperature of the low temperature side evaporator 42 or the low temperature side circulation circuit (typically, the low temperature side condenser 41 or the cold head of the Stirling refrigerating engine 30). In the present embodiment, it is sufficient that the temperature of the refrigerant in the low-temperature side circulation circuit 40 can be directly detected, but instead of the direct detection, the low-temperature side evaporator 42, the low-temperature side condenser 41, or the Stirling refrigeration is used. The temperature of the cold head of the engine 30 is detected. Therefore, the temperature sensor 81 may detect the cold head of the low temperature side evaporator 42, the low temperature side condenser 41, and the Stirling refrigeration engine 30! /, But the temperature of the deviation is preferably detected. It is the temperature of the side condenser 41, more preferably the temperature of the cold head.

The control unit 90 controls the drive of the Stirling refrigeration engine 30. The Stirling refrigeration engine can be driven by changing its load. A Stirling refrigeration engine has a high cooling capacity when driving a heavy load and a low cooling capacity when driving a small load. The controller 90 controls the air volume of the cooling fan 22 and the blower fan 62. The control unit 90 may perform switching control for driving or stopping the cooling fan 22 and the blower fan 62. Further, the control unit 90 performs switching control of the damper 61 between an open state and a closed state.

FIG. 4 is a flowchart showing the flow of the freeze prevention process executed in the refrigerator in the first embodiment. Referring to FIG. 4, control unit 90 of refrigerator 1 receives the temperature of the cold head of Stirling refrigeration engine 30 from temperature sensor 81. The controller 90 determines whether or not the temperature of the cold head is lower than a predetermined temperature T (step S01). If true, the process proceeds to step S02. If false, the process is terminated. The predetermined value T is a value determined in advance from the freezing point of the refrigerant in the low-temperature side circulation circuit 40, and is set to a temperature about 3 ° C. higher than the freezing temperature of the refrigerant. The coolant temperature is not necessarily the same as the cold head temperature. I won't do it, but it won't be lower than the cold head temperature. If the temperature difference D between the refrigerant temperature and the cold head temperature is a component, the predetermined temperature should be equal to or greater than the value obtained by subtracting the temperature difference D from the freezing point of the refrigerant.

[0049] When the temperature sensor 81 detects the temperature of the low temperature side evaporator 42 or the low temperature side condenser 41, the temperature of the low temperature side evaporator 42 or the low temperature side condenser 41 is equal to the temperature of the refrigerant. It doesn't always match! However, the temperature of the refrigerant cannot be higher than the temperature of the low-temperature evaporator 42 or the low-temperature condenser 41. If the temperature difference D1 between the refrigerant temperature and the low-temperature side evaporator 42 or the low-temperature side condenser 41 is divided, the predetermined temperature is equal to or greater than the refrigerant freezing point plus the temperature difference D1. If you do.

[0050] In step S02, the Stirling refrigeration engine is stopped. This prevents the refrigerant from being cooled and freezing.

[0051] In step S02, a force Stirling refrigeration engine that stops the Stirling refrigeration engine may be driven with a small load. In this case, although the refrigerant is cooled, it is possible to prevent the refrigerant from freezing if it is driven with a load sufficient to maintain the temperature of the refrigerant at that temperature.

[0052] <Modification of antifreeze treatment>

FIG. 5 is a flowchart showing a flow of the modified anti-freezing process executed in the refrigerator in the first embodiment. Referring to FIG. 5, control unit 90 of refrigerator 1 receives the temperature of the cold head of Stirling refrigeration engine 30 from temperature sensor 81. The control unit 90 determines whether or not the temperature of the cold head is lower than a predetermined temperature T (step S11). If true, proceed to step S12, and if false, proceed to step S20.

In step S 12, it is determined whether or not the cooling fan 22 has stopped power. If the cooling fan 22 is stopped, the process proceeds to step S13, and if stopped, the process proceeds to step S14. In step S13, the cooling fan 22 is driven. When the cooling fan 22 is driven, air around the low temperature side evaporator 42 is convected, and the low temperature side evaporator 42 is supplied with air at a relatively high temperature. For this reason, it is prevented that the temperature of a refrigerant | coolant falls. On the other hand, when proceeding to step S14, since the cooling fan 22 is driven, the air flow of the cooling fan is increased and driven. As a result, the air around the low-temperature evaporator 42 convects more violently and the refrigerant temperature The degree is prevented from decreasing.

[0054] In step S15, it is determined whether or not a predetermined time has passed. If true, the process proceeds to step S16, and if false, the process returns to step S11. In step S16, it is determined whether or not the blower fan 62 is stopped. If the blower fan 62 is stopped, the process proceeds to step S17, and if not stopped, the process proceeds to step S19. In step S17, the damper is opened, and the blower fan 62 is driven in the next step S18. When the blower fan 62 is driven, air around the low-temperature side evaporator 42 is convected, and air having a relatively high temperature is supplied to the low-temperature side evaporator 42. For this reason, it is further prevented that the temperature of a refrigerant | coolant falls. On the other hand, when proceeding to Step S19, since the blower fan 62 is driven, the blower fan is driven by increasing the air volume. As a result, the air around the low-temperature evaporator 42 is more convectively prevented from lowering the refrigerant temperature.

[0055] After step S18 or step S19, the process returns to step S11. In step S11, it is determined again whether the temperature of the cold head is lower than a predetermined temperature T. If the temperature is not lower than the predetermined temperature T, the process proceeds to step S12 if the force to proceed to step S20 is low. That is, the processes of Step S12 to Step S19 described above are executed until the temperature of the cold head is equal to or exceeds the predetermined temperature T. In step S20, the cooling fan 22, the damper 61, and the blower fan 62 are driven in the normal operation mode.

As described above, in the modified example of the first embodiment, the cooling fan or both the cooling fan and the blower fan are driven. For this reason, the air around the low-temperature side evaporator 42 can be convected to prevent the refrigerant temperature from being lowered. In addition, the refrigerant can be prevented from freezing.

[0057] It should be noted that the above-described control for driving the Stirling refrigeration engine 30 while stopping or lowering the cooling capacity and the control for driving the cooling fan or both the cooling fan and the blower fan are executed in combination. Also good. Thereby, it is possible to further prevent the refrigerant from freezing.

[0058] As described above, the refrigerator 1 in the first embodiment is configured such that the temperature of the cold head 42, the low temperature condenser 41, or the cold head of the Stirling refrigeration engine 30 falls below a predetermined temperature T. , Power to reduce the cooling capacity of Stirling refrigeration engine or stopped Make it. For this reason, it is possible to suppress the cooling of the refrigerant and to prevent the refrigerant from freezing.

[0059] Further, when the temperature of the cold head 42 of the low temperature side evaporator 42, the low temperature side condenser 41 or the Stirling refrigeration engine 30 falls below the predetermined temperature T, the cooling fan 22 is driven or the air volume is increased. Therefore, the air around the low-temperature side evaporator 42 can be convected to prevent the refrigerant from freezing.

[0060] In the first embodiment, for example, the predetermined temperature T is about 3 ° C higher than the freezing point of the refrigerant. However, the predetermined temperature T may be other temperature as long as it is higher than the freezing point of the refrigerant. /.

[0061] In this case, by setting the lower temperature in the temperature range of the refrigerant that can be obtained when the Stirling refrigeration engine 30 is operated in the rated state as the predetermined temperature T, the refrigerant temperature can be reduced. It is possible to prevent the temperature from falling below the temperature range of the refrigerant that can be obtained during rated operation.

[0062] This prevents the refrigerant from being overcooled by the operation of the Stirling refrigeration engine 30 and prevents the cold head from being overcooled, so that the Stirling refrigeration engine 30 exceeds the rated state and becomes overloaded. Can be prevented. As a result, deterioration of the Stirling refrigeration engine 30 can be prevented.

[0063] <Second Embodiment>

Next, the refrigerator in the second embodiment will be described. The refrigerator in the second embodiment has the same configuration except that the refrigerator in the first embodiment has a different freeze prevention function. Hereinafter, the freeze prevention function in the second embodiment will be described.

[0064] FIG. 6 is a functional block diagram showing the freeze prevention function of the refrigerator in the second embodiment. Referring to FIG. 6, refrigerator 1 includes a control unit 90 for controlling the entire refrigerator, an upper door opening / closing detection switch 82 connected thereto, and a lower door opening / closing detection switch 83. The control unit 90 is connected to the Stirling refrigeration engine 30, the cooling fan 22, the damper 61, and the air supply fan 62.

[0065] The upper door open / close detection switch 82 has the force of closing or closing the upper door 14 open. Detect whether it is in a closed state. The lower door opening / closing detection switch 83 detects whether the lower door 15 is in an open state or in a closed state.

[0066] FIG. 7 is a flowchart showing a flow of anti-freezing processing executed in the refrigerator in the second embodiment. Referring to FIG. 7, control unit 90 of refrigerator 1 receives the open / close state of upper door 14 and lower door 15 from upper door open / close detection switch 82 or lower door open / close detection switch 83. The control unit 90 determines whether one of the upper door 14 and the lower door 15 has been opened (step S21). If either the upper door 14 or the lower door 15 is open, the process proceeds to step S22, and if not, the process ends.

[0067] In step S22, the cooling fan 22 is stopped. As a result, it is possible to prevent the cold air in the cooling chambers 11 and 12 of the door that has been opened from being forced out. In the next step S23, it is determined whether or not a predetermined time has elapsed. This elapsed time is the time measured after step S21 detects that either upper door 14 or lower door 15 is open, or the time measured when the cooling fan is stopped. Either may be used. If the predetermined time has elapsed, the process proceeds to step S24, and if not, the process returns to step S21. By stopping the cooling fan, the air around the low-temperature evaporator 42 will not convect. Thereby, the temperature of a refrigerant | coolant will fall. The predetermined time is shorter than the time until the temperature of the refrigerant starts to decrease and the force freezing point is reached. The predetermined time may be a single predetermined time, or may be a predetermined time for each load of the Stirling refrigeration engine. Furthermore, it is possible to set a predetermined time for each of the temperature in the refrigerator and the load of the Stirling freezing engine.

[0068] In the next step S24, the Stirling refrigeration engine is stopped. This prevents the refrigerant from being cooled and prevents the refrigerant from freezing.

[0069] In step S24, the Stirling refrigeration engine that stops the Stirling refrigeration engine may be driven with a small load. In this case, although the refrigerant is cooled, it is possible to prevent the refrigerant from freezing if it is driven with a load sufficient to maintain the temperature of the refrigerant at that temperature.

[0070] <First Modification of Freezing Prevention Treatment>

FIG. 8 shows a modified anti-freezing process executed in the refrigerator in the second embodiment. It is a flowchart which shows the flow. Referring to FIG. 8, control unit 90 determines whether the upper door 14 is open or not (step S31). If the upper door 14 is in the open state, the process proceeds to step S32, and if not, the process proceeds to step S38.

[0071] In step S32, the blower fan 62 is stopped, and in step S33, the cooling fan 22 is stopped. Thereby, even if the upper door 14 is in the open state, it is possible to prevent the cold air in the cooling chamber 11 from being forced out to the outside. Then, it is determined whether or not the force has passed for a predetermined time (step S34). If the predetermined time has elapsed, the process proceeds to step S35, and if not, the process returns to step S31. That is, if a predetermined time elapses with the upper door 14 open, the force proceeds to step S35. If the upper door 14 is closed before the predetermined time elapses, the process proceeds to step S38. By stopping the cooling fan 22 in step S33, the air around the low temperature evaporator 42 is not convected. Thereby, the temperature of a refrigerant | coolant will fall. If the cooling fan 22 is left stopped, the temperature of the refrigerant will drop and reach the freezing point. Therefore, the predetermined time is a time shorter than the time until the temperature of the refrigerant reaches the freezing point. The predetermined time may be a single predetermined time, or may be a predetermined time for each load of the Stirling freezing engine. Furthermore, it is possible to set a predetermined time for each temperature in the refrigerator and the load of the Stirling refrigeration engine.

[0072] In step S35, the damper 61 is closed, and in step S36, the cooling fan 22 is driven. As a result, the cold air around the low-temperature side evaporator 42 is sent to the cooling chamber 12 and is not sent to the cooling chamber 11 because the force damper 61 is closed! /. For this reason, air around the low-temperature side evaporator 42 is convected, and air having a relatively high temperature is supplied to the low-temperature side evaporator 42. And it prevents that the temperature of a refrigerant falls. As a result, the refrigerant is prevented from freezing. Further, since the cool air around the low-temperature side evaporator 42 is not sent to the cooling chamber 11, it is possible to prevent the cool air in the opened upper door cooling chamber 11 from being forced to flow out.

[0073] In step S37, it is determined whether or not the upper door 14 is closed. If the upper door 14 is closed, the process proceeds to step S38, and if not, the process returns to step S35. Until the upper door 14 is closed, the cool air around the low-temperature side evaporator 42 is sent to the cooling chamber 12, thereby preventing the refrigerant from freezing. In step S38, the cooling fan 22, the damper 61, and the blower fan 62 are driven in the normal operation mode.

[0075] In the next step S39, the control unit 90 determines whether or not the lower door 15 is open. If the lower door 15 is opened, the process proceeds to step S40, and if not, the process is terminated.

[0076] In step S40, the blower fan 62 is stopped, and in step S41, the cooling fan 22 is stopped. Thereby, even if the lower door 15 is opened, it is possible to prevent the cold air in the cooling chamber 12 from being forced out. Also, the air around the low-temperature evaporator 42 will not convect. Then, it is determined whether or not the force has passed for a predetermined time (step S42). If the predetermined time has elapsed, the process proceeds to step S43, and if not, the process returns to step S39. That is, when a predetermined time elapses while the lower door 15 is open, the force proceeds to step S43. If the lower door 15 is closed before the predetermined time elapses, the process is terminated. The predetermined time is the same time as in step S34.

In step S43, the damper 61 is opened, and in step S44, the blower fan 62 is driven. As a result, the cold air around the low-temperature side evaporator 42 is sent to the cooling chamber 11, but is not sent to the cooling chamber 12. For this reason, the air around the low-temperature side evaporator 42 is convected, and air having a relatively high temperature is supplied to the low-temperature side evaporator 42. For this reason, it is prevented that the temperature of a refrigerant | coolant falls. As a result, the refrigerant is prevented from freezing. Further, since the amount of cool air around the low-temperature side evaporator 42 is not sent to the cooling chamber 12, it is possible to reduce the forced outflow of cool air in the cooling chamber 12 from the opened lower door. .

In Step S45, it is determined whether or not the lower door 15 is closed. If the lower door 15 is closed, the process proceeds to step S46, and if not, the process returns to step S43. Therefore, until the lower door 15 is closed, the cool air around the low-temperature side evaporator 42 is sent to the cooling chamber 11, thereby preventing the refrigerant from freezing.

[0079] In step S46, the cooling fan 22, the damper 61, and the blower fan 62 are driven in a normal operation mode.

[0080] The refrigerator 1 in the second embodiment reduces the cooling capacity of the Stirling refrigeration engine when the open state of either the upper door 14 or the lower door 15 continues for a predetermined time. Or stop. For this reason, it is possible to suppress the cooling of the refrigerant and to prevent the refrigerant from freezing.

[0081] In addition, when the open state of either the upper door 14 or the lower door 15 continues for a predetermined time, the cooling fan 22 is driven or the air volume is increased, so the air around the low-temperature side evaporator 42 is increased. The refrigerant can be prevented from freezing by convection.

[0082] Further, when the lower door 15 is kept open for a predetermined time, the damper 61 is closed and the cooling fan 22 is driven. When the upper door is kept open for a predetermined time, the damper 61 is opened and the blower fan is turned on. Drive 62. For this reason, it is possible to prevent the refrigerant from freezing and prevent the cool air inside the cabinet from leaking outside, regardless of whether the upper door 14 or the lower door 15 is opened. .

[0083] In the present invention, the cooling fan 22 is stopped to cool the air around the low-temperature side evaporator 42 in order to quickly pass through the maximum ice crystal formation zone (13 ° C to 17 ° C) when the food is frozen. It is also applicable to the quick freezing operation in which the cooling fan 22 is driven after the temperature is lowered to a very low temperature.

[0084] In the second embodiment, when the upper door 14 or the lower door 15 is opened, the cooling fan 22 is stopped to prevent the cool air from flowing out, and a predetermined time has elapsed. After that, the Stirling refrigeration engine 30 was stopped.

However, the present invention is not limited to this, and when the upper door 14 or the lower door 15 is opened, the cooling fan 22 may be stopped and the Stirling refrigeration engine 30 may be stopped. In order to prevent the temperature in the refrigerator 1 from rising, if control is performed to rapidly reduce the temperature of the cold head of the Stirling refrigeration engine 30, a refrigerant freezing accident may occur due to a control delay in stopping the Stirling refrigeration engine 30. May occur.

[0086] For this reason, even when the door of the refrigerator 1 is in an open state, control is performed to reduce the temperature of the cold head of the Stirling refrigeration engine 30 to prevent the temperature inside the refrigerator 1 from rising. Since the Stirling refrigeration engine 30 is stopped at, the refrigerant can be prevented from freezing.

[0087] In the second embodiment, when the upper door 14 or the lower door 15 is opened, the cooling fan 22 is stopped, and after a predetermined time has elapsed, the Stirling freezing engine 30 is stopped. I tried to make it. [0088] However, the present invention is not limited to this, and when the upper door 14 or the lower door 15 is opened, the cooling fan 22 is stopped and the temperature of the cold head of the Stirling refrigeration engine 30 is lowered to a predetermined temperature. Sometimes, the Stirling refrigeration engine 30 may be stopped.

Thereby, it is possible to prevent the refrigerant from freezing due to the temperature drop of the cold head of the Stirling refrigerating engine 30. Further, the electric power input to the Stirling refrigeration engine 30 may be reduced stepwise until the door is opened and the force is also stopped until the Stirling refrigeration engine 30 is stopped. Thereby, even when the door is in an open state, it is possible to suppress an increase in temperature in the refrigerator 1 due to the outflow of cold air, and at the same time, it is possible to prevent the refrigerant from freezing.

[0090] Further, when the upper door 14 or the lower door 15 is opened, when the upper door 14 and the lower door 15 are closed after the Stirling freezing engine 30 is stopped, immediately or It is preferable to operate the Stirling refrigeration engine 30 after a predetermined time (for example, after 5 seconds). Thereby, the temperature in the refrigerator 1 that has risen due to the cold air that has flowed out can be quickly cooled.

[0091] Also, when the temperature of the cold head of the Stirling refrigeration engine 30 rises to a predetermined temperature after the Stirling refrigeration engine 30 is stopped when the upper door 14 or the lower door 15 is opened, the Stirling refrigeration engine 30 is stopped. It is preferable to operate the refrigeration engine 30. As a result, the temperature in the refrigerator 1 can be prevented from rising excessively.

Further, in the second embodiment, the cooling fan 22 is stopped when the upper door 14 or the lower door 15 is opened. However, the present invention is not limited to this, and the cooling fan 22 may be operated at a low rotational speed. As a result, since heat is applied to the aerodynamic refrigerant in the refrigerator 1 that is higher than the temperature of the refrigerant, the temperature of the refrigerant gradually increases, and the refrigerant can be prevented from freezing.

In the second embodiment, the Stirling refrigeration engine 30 is stopped when the upper door 14 or the lower door 15 is opened. However, the present invention is not limited to this, and the input power to the Stirling refrigeration engine 30 may be reduced. This also reduces the amount of heat taken from the refrigerant, increasing the temperature of the refrigerant and freezing the refrigerant. Can be prevented.

[0094] In the second embodiment, the predetermined time is shorter than the time from when the cooling fan 22 is stopped until the temperature of the dynamic cooling medium reaches the freezing point. However, the present invention is not limited to this, and the predetermined time may be the time from when the cooling fan 22 is stopped until the refrigerant reaches the predetermined temperature! The predetermined temperature may be a temperature higher than the freezing point of the refrigerant.

Thereby, the temperature of the refrigerant can be prevented from reaching a predetermined temperature. For this reason, by setting the lower temperature of the refrigerant temperature range that can be obtained in the rated operation of the Stirling refrigeration engine 30 to a predetermined temperature, the refrigerant temperature range that can be obtained in the rated operation of the Stirling refrigeration engine 30 The following can be prevented.

[0096] This prevents the refrigerant from being overcooled by the operation of the Stirling refrigeration engine 30 and prevents the cold head from being overcooled, so that the Stirling refrigeration engine 30 exceeds the rated state and becomes overloaded. This can be prevented. As a result, deterioration of the Stirling refrigeration engine 30 can be prevented.

Next, the refrigerator in the third embodiment will be described. The refrigerator in the third embodiment has the same configuration except that the refrigerator in the first embodiment has a different freeze prevention function. Hereinafter, the antifreezing function in the third embodiment will be described.

[0098] FIG. 9 is a functional block diagram showing the freeze prevention function of the refrigerator in the third embodiment. Referring to FIG. 9, the refrigerator 1 includes a control unit 90 for controlling the entire refrigerator 1, a temperature sensor 81 connected thereto, an upper door opening / closing detection switch 82, and a lower door opening / closing detection switch. 83. The control unit 90 is connected to the Stirling refrigeration engine 30, the cooling fan 22, the damper 61, the blower fan 62, and the display unit 91.

[0099] Display unit 91 displays information related to the operating state of the refrigerator. For example, the display unit 91 displays that the Sternling refrigeration engine 30 is abnormal, the temperature sensor 81 displays that there is an abnormal force S, and the upper door 14 and the lower door 15 are open. To indicate that it is in normal operation. Also, let us notify you of the abnormality by voice according to the display on the display unit 91. [0100] FIG. 10 is a flowchart showing the flow of the freeze prevention process executed in the refrigerator in the third embodiment. Referring to FIG. 10, control unit 90 of refrigerator 1 detects whether or not temperature sensor 8 1 has an abnormality. The controller 90 determines whether or not the thermistor of the temperature sensor 81 is abnormal (step S71). If the thermistor is abnormal, the process proceeds to step S72. If the thermistor is not abnormal, the process proceeds to step S74. In step S72, the display unit 91 displays that the thermistor is abnormal. Then, the Stirling refrigerating engine 30 is stopped (step S73). Thereafter, the process ends.

[0101] As described above, when the thermistor is abnormal, the Stirling refrigerating engine 30 is stopped regardless of the refrigerant temperature. As a result, the refrigerant is no longer cooled by the Stirling refrigerating engine 30, so that the refrigerant can be prevented from freezing. In addition, it is possible to prevent the Stirling refrigeration engine 30 from being inadvertently stopped in S86 due to a malfunction of the thermistor that is detected at a temperature lower than the actual temperature in S83 described later. Also, due to the malfunction of the thermistor, a temperature higher than the actual temperature is detected in S83, which will be described later, and the Stirling refrigeration engine 30 despite the fact that the refrigerant has been frozen by reaching the freezing temperature. Can be prevented from being stopped.

Further, the temperature of the cold head of the Stirling refrigeration engine 30 is input from the temperature sensor 81 to the control unit 90 of the refrigerator 1. The control unit 90 has a cold head temperature T

It is determined whether it is lower than 1 (step S74). If the temperature is lower than T, proceed to step S75.

1

If the temperature is not lower than T, return to step S71. The temperature T is, for example, that of the refrigerant

1 1

The temperature is about 3 ° C higher than the solidification temperature.

The open / close state of the upper door 14 and the lower door 15 is input to the control unit 90 of the refrigerator 1 from the upper door open / close detection switch 82 or the lower door open / close detection switch 83. The control unit 90 determines whether one of the upper door 14 and the lower door 15 is open (step S75). If either the upper door 14 or the lower door 15 is opened, the process proceeds to step S76, and if not, the process proceeds to step S77.

[0104] In step S76, the control unit 90 notifies the display unit 91 of a warning that the upper door 14 and the lower door 15 are open. Then, return to S71.

[0105] In step S77, the rotation speed of the cooling fan 22 is equal to the maximum allowable rotation speed of the cooling fan 22. It is determined whether or not it is correct. If the maximum allowable rotational speed is not set, the process proceeds to step S78. If the maximum allowable rotational speed is set, the process proceeds to step S81.

In step S78, the rotation speed of the cooling fan 22 is set as the maximum allowable rotation speed of the cooling fan 22. As a result, the air around the low-temperature side evaporator 42 convects more violently than when the number of rotations of the cooling fan 22 is less than the maximum allowable number of rotations, and a decrease in the refrigerant temperature can be suppressed. Then, it is determined whether or not the rotation speed of the cooling fan 22 is the maximum allowable rotation speed and the force has also passed for a predetermined time (step S79). If the predetermined time has not elapsed, S79 is repeated, and if the predetermined time has elapsed, the process proceeds to step S82.

[0107] During this predetermined time, when the rotation speed of the cooling fan 22 is set to the maximum allowable rotation speed during normal operation, the temperature of the refrigerant increases at least by a temperature at which the temperature sensor 81 can detect that the temperature has increased. It is preferable that it is more than the time required to do. For example, when the temperature detection error of the temperature sensor 81 is ± 0.5 ° C., the predetermined time may be a time longer than the time required for the refrigerant temperature to rise by at least 1 ° C.

[0108] In addition, during the predetermined time, when the rotation speed of the cooling fan 22 is set to the maximum allowable rotation speed during abnormal operation, the temperature of the cold head is decreased from the temperature T to a temperature T described later.

1 2

Preferred to be less than an hour.

In step S81, the input power to the Stirling refrigeration engine 30 is decreased by a predetermined amount. As a result, the cooling capacity of the Stirling refrigeration engine 30 is reduced. Therefore, the amount of heat deprived of the refrigerant power can be reduced, and the temperature drop of the refrigerant can be suppressed.

[0110] In step S82, the controller 90 determines whether or not the temperature of the cold head is lower than the temperature T.

1

Judge again. If it is not lower than the temperature T, proceed to step S83.

If 1 1, go to step S84.

[0111] That is, when the process proceeds to step S83, the rotation speed of the cooling fan 22 is set to the maximum allowable rotation speed in step S78, or the input power to the Stirling refrigeration engine 30 is decreased in step S81. The temperature from the abnormal value where the temperature of the cold head is lower than the temperature T

1

It means that the normal value is not lower than T. If you proceed to Step S84, go to Cold

1

The temperature of the lid remains abnormal.

[0112] In step S83, Stirling refrigeration engine 30, cooling fan 22, damper 61 and The operation mode of the blower fan 62 is switched to the normal operation mode. Thereafter, the process returns to step S71.

[0113] In step S84, the controller 90 determines whether or not the temperature of the cold head is lower than the temperature T.

2

to decide. If it is not lower than the temperature T, return to step S81, and if it is lower than the temperature T,

twenty two

Proceed to step S85. The temperature T is, for example, about 1 ° C higher than the solidification temperature of the refrigerant.

2

is there.

[0114] In step S85, the control unit 90 displays on the display unit 91 that the Stirling refrigeration engine 30 is abnormal. In step S86, the control unit 90 stops the Stirling refrigeration engine 30. Thereafter, the process ends.

In the present embodiment, the rotational speed of cooling fan 22 is set to the maximum allowable rotational speed in step S78, but the rotational speed of cooling fan 22 may be increased stepwise. If the temperature of the cold head exceeds the temperature T after a predetermined time

1

Return to normal operation.

[0116] Thus, if the temperature of the cold head exceeds the temperature T before the rotation speed of the cooling fan 22 reaches the maximum allowable rotation speed, the rotation speed of the cooling fan 22 is increased more than necessary.

1

Electricity consumption that does not need to be burned can be reduced. In addition, since the temperature change of the refrigerant becomes gentle, the temperature of the refrigerant can be controlled with higher accuracy than when the temperature change of the refrigerant is abrupt.

[0117] In the method of cooling the inside of the refrigerator 1 using the refrigerant, the refrigerant may freeze.

If the operation of the Stirling refrigeration engine 30 is continued with the refrigerant frozen, there is a possibility that the temperature of the cold head rapidly decreases and the Stirling refrigeration engine 30 breaks down.

[0118] Therefore, it is necessary to detect the temperature of the low-temperature side circulation circuit 40 of the Stirling refrigeration engine 30 and stop the Stirling refrigeration engine 30 when the temperature of the low-temperature side circulation circuit 40 reaches near the freezing temperature of the refrigerant. . However, suddenly stopping the Stirling refrigeration engine 30 is not preferable because the reliability of the refrigerator 1 as a product is greatly impaired.

[0119] As described above, the refrigerator 1 in the third embodiment differs from the stop control before performing the stop control for stopping the Stirling refrigeration engine 30 to prevent the refrigerant from freezing. Anti-freezing control to prevent the refrigerant from freezing, eg cooling By controlling the rotational speed of the fan 22 to the maximum allowable rotational speed or reducing the input power to the Stirling refrigeration engine 30, the refrigerant is prevented from freezing.

[0120] Therefore, when the refrigerant can be prevented from freezing by the freeze prevention control, it is not necessary to perform the stop control of the Stirling refrigerating engine 30. As a result, the Stirling freezing engine 30 can be prevented from being stopped as much as possible. As a result, the reliability of the refrigerator as a product can be improved.

[0121] Further, when the temperature is detected by the temperature sensor 81, for example, an abnormality in temperature detection such as an abnormality in the thermistor of the temperature sensor 81 is detected, thereby preventing erroneous detection of the temperature of the temperature sensor 81. be able to. For this reason, the temperature T in step S84

2

Based on the false detection, the Stirling refrigeration engine 30 can be prevented from being stopped in step S86.

[0122] Further, anti-freezing control is performed when the temperature falls below a temperature T higher than the temperature at which the refrigerant freezes.

1

And when the temperature falls below the temperature τ higher than the temperature at which the refrigerant freezes and lower than the temperature τ.

1 2

Then, the Stirling refrigeration engine 30 is controlled to stop. Therefore, if the freezing prevention control prevents the refrigerant from freezing below the temperature T, the Stirling cooling

2

It is not necessary to perform stop control of the frost engine 30. As a result, the Stirling freezing engine 30 can be prevented from being stopped as much as possible.

[0123] Further, since the air volume of the cooling fan 22 is increased, the air around the low-temperature side evaporator 42 is convected. For this reason, since the air newly sent to the low temperature side evaporator 42 gives heat to the refrigerant, the temperature of the refrigerant rises. As a result, the refrigerant can be prevented from freezing.

[0124] In addition, since the air in the box is convected by the cooling fan 22, the low-temperature evaporator 42 can efficiently cool the air in the box. As a result, the COP (Coefficient Of Performance) of the Stirling refrigeration engine 30 can be improved.

[0125] Here, COP indicates the heating or cooling capacity per power consumption of the heating device or the cooling device, the amount of heat given to the non-heated material or the amount of heat taken from the non-cooled material, and the heating or cooling capacity. Therefore, it is calculated as the ratio of the input energy consumed for heat generation to the calorific value conversion value. In the present embodiment, the cooling device is the refrigerator 1 and the non-cooled material is cooled by the refrigerant cooled by the cold head of the Stirling refrigeration engine 30. It is the air in the storage 1. Also, let Q be the amount of heat taken from uncooled material, and input energy

OUT

COP can be calculated by the following formula: COP = Q / Q

IN OUT IN

The

In other words, the amount of heat efficiently deprived from the aerodynamic force convected by the cooling fan 22 by the refrigerant cooled by the Stirling refrigeration engine 30, so that the converted amount of heat Q

IN

However, the amount of heat Q deprived of aerodynamic force increases and COP improves.

OUT

[0127] Further, if the air temperature is deprived of heat, and the heat is given to the refrigerant, the temperature of the refrigerant does not rise and is lower than the temperature T.

1

The cooling capacity of the engine 30 is reduced, that is, the input power input to the Stirling refrigeration engine 30 is controlled to be reduced.

[0128] For this reason, since the cooling of the refrigerant by the Stirling refrigerating engine 30 is suppressed, the temperature of the refrigerant rises. As a result, the refrigerant can be prevented from freezing.

[0129] Further, since the rotation speed of the cooling fan 22 is driven at the maximum allowable rotation speed of the cooling fan 22, it is possible to further prevent the refrigerant from freezing compared to when the rotation speed is not the maximum allowable rotation speed. it can. In addition, since the convection air force S is further convected by the cooling fan 22 by setting the maximum allowable rotation speed, the COP of the Stirling refrigeration engine 30 can be further improved.

[0130] Also, increase the air volume of the cooling fan 22! If the temperature of the refrigerant does not rise and is below the temperature T even though the amount of heat is given to the refrigerant, the Stirling refrigeration engine

1

Control to reduce the input power of 30. For this reason, since cooling of a refrigerant | coolant is suppressed, the temperature of a refrigerant | coolant rises. As a result, the refrigerant can be prevented from freezing.

[0131] Further, since the Stirling refrigeration engine 30 has an abnormality before the refrigerant freezes, the fact that the refrigerant is frozen is notified, so that an emergency measure against the refrigerant freezing, such as opening and closing the door, can be urged.

[0132] In the third embodiment, for example, the temperature T is about 3 ° C from the freezing point of the refrigerant.

1

The temperature τ is higher than the freezing point of the refrigerant.

The temperature was about 2c higher. However, the temperatures τ and τ are higher than the freezing point of the refrigerant,

1 2 τ 1> τ at other temperatures

2

Even if there is! [0133] In this case, the lower temperature of the temperature range of the refrigerant that can be obtained when the Stirling refrigeration engine 30 is operated in the rated state is defined as the temperature T, and the higher temperature of the aforementioned temperature range.

2

Lower temperature, a number from temperature T. C By setting the high temperature to temperature T,

twenty one

It is possible to prevent the temperature from becoming below the temperature range of the refrigerant that can be taken in the rated operation of the Stirling refrigeration engine 30.

Accordingly, the refrigerant is not cooled excessively by the operation of the Stirling refrigerating engine 30 and the cold head can be prevented from being overcooled, so that the Stirling refrigerating engine 30 exceeds the rated state and is overloaded. Can be prevented. As a result, deterioration of the Stirling refrigeration engine 30 can be prevented.

[0135] The force of the first embodiment up to the third embodiment is the same as the force described for the refrigerator 1 as shown in FIG. 4, FIG. 5, FIG. 7, FIG. 8, and FIG. Control method of the refrigerator 1 or the Stirling refrigeration engine 30, a control program for the refrigerator 1 or the Stirling refrigeration engine 30 that executes the processes shown in FIG. 4, FIG. 5, FIG. 7, FIG. 8, and FIG. The invention can be captured as a Stirling refrigeration engine 30 provided in the refrigerator 1

[0136] Power that has described and illustrated this invention in detail. This is by way of example only and should not be limiting, and the spirit and scope of the invention is limited only by the scope of the appended claims. It will be clearly understood.

Claims

The scope of the claims

[1] A refrigerator (1) that cools the interior with a Stirling refrigeration engine (30),

State detection means (81, S) for detecting an overcooled state of the Stirling refrigeration engine

01, Sl l, S21, S31, S37, S39, S45, S74, S75, S82, S84), and

A cooling cabinet comprising supercooling prevention means (S02) for preventing the Stirling refrigeration engine from being overcooled based on detection of the overcooled state by the state detection means;

[2] Door state detection means (82, 83) for detecting the open / closed state of the doors (14, 15) provided in the cooling chambers (11, 12) of the refrigerator,

A cooling fan (22) for supplying cold air cooled by the Stirling refrigeration engine into the cabinet;

Cooling fan control means (S22) for stopping the cooling fan while the door state detecting means detects that the door is in an open state,

The refrigerator according to claim 1, wherein the state detecting means detects that a predetermined time has elapsed since the door state is detected by the door state detecting means (S23).

[3] The refrigerator includes a first cooling chamber (12) and a second cooling chamber (11) each partitioned by a heat insulating material and having a door,

The cooling fan supplies cold air cooled by the Stirling refrigeration engine to the first cooling chamber,

An air passage (20, 21, 21A) for guiding the cold air cooled by the Stirling refrigeration engine to the second cooling chamber;

A blocking means (61) provided in the air passage for blocking the cool air cooled by the Stirling refrigeration engine;

An air supply fan (62) for blowing cool air cooled by the Stirling refrigerating engine to the air passage,

The overcooling prevention means is used as the blocking means when the door state detection means detects the closed state of the first cooling chamber door and the open state of the second cooling chamber door (S31). The air passage is shut off (S35) and the stop of the cooling fan is released to drive (S36) When the door state detection means detects the open state of the first cooling chamber door and the closed state of the second cooling chamber door (S39), 3. The refrigerator according to claim 2, wherein the air blower is blocked (S43) and the blower fan is driven (S44).

[4] The apparatus further includes a low-temperature side evaporator (42) that receives cold from a low-temperature portion formed in the Stirling refrigeration engine via a secondary refrigerant,

The state detection means includes temperature detection means (81) for detecting the temperature of the low temperature part, the low temperature side evaporator or the low temperature side condenser (41) paired with the low temperature side evaporator, and the temperature detection means Detects that the temperature detected by is below the specified temperature (SOI, S

11, S74, S82, S84), the refrigerator according to claim 1.

[5] The overcooling prevention means is a control different from the stop control before the Stirling refrigeration engine is overcooled before the stop control (S24, S86) for controlling and stopping the Stirling refrigeration engine. 5. The refrigerator according to claim 4, wherein a supercooling prevention control (S22, S78, S81) is performed to prevent the occurrence of failure.

[6] The predetermined temperature includes a first temperature (T) higher than a temperature at which the Stirling refrigeration engine is supercooled and a temperature higher than the temperature at which the Stirling refrigeration engine is supercooled.

1

And a second temperature (T) lower than the temperature of

2

The supercooling prevention unit performs the supercooling prevention control when the state detection unit detects that the temperature is lower than the first temperature, and further, the refrigerant state detection unit sets the second temperature. 6. The refrigerator according to claim 5, wherein the stop control is performed when it is detected that the value has fallen below.

[7] The refrigerator according to claim 4, further comprising temperature detection abnormality detection means (81) for detecting abnormality of temperature detection by the temperature detection means when temperature is detected by the temperature detection means.

[8] A cooling fan (22) for supplying cold air cooled by the low-temperature side evaporator into the cabinet is further provided,

5. The refrigerator according to claim 4, wherein the overcooling prevention means drives the cooling fan (S13, S36) or increases the air volume of the cooling fan (S14, S78).

[9] The overcooling preventing means drives the cooling fan or increases the airflow of the cooling fan when the state detecting means detects that the temperature is below the first temperature (S74). (S78) Further, after a predetermined time has elapsed since the cooling fan was driven or the air volume of the cooling fan was increased (S79), it was detected by the state detection means that the temperature was below the first temperature. 9. The refrigerator according to claim 8, wherein the cooling capacity is reduced by controlling the Stirling refrigeration engine (S81) when the engine is in operation (S82).

[10] The overcooling prevention means includes a rotation speed control means (90) for controlling the rotation speed of the cooling fan,

The overcooling prevention means drives the cooling fan by setting the rotational speed of the cooling fan to the maximum rotational capacity when the state detection means detects that the temperature is below the first temperature. (S78) and, after a predetermined time has elapsed since the cooling fan was driven at the maximum speed (S79), when the state detecting means detects that the temperature has dropped below the first temperature. (S82) The refrigerator according to claim 8, wherein the Stirling refrigeration engine is controlled to reduce the cooling capacity (S81).