WO2007080708A1

WO2007080708A1 - Cooling chamber

Info

Publication number: WO2007080708A1
Application number: PCT/JP2006/323193
Authority: WO
Inventors: Keiji Fujiwara
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-01-10
Filing date: 2006-11-21
Publication date: 2007-07-19

Abstract

Cold energy of a cold head of a Sterling refrigerating machine is transmitted to a cooling space in a heat insulation housing by a low temperature-side circulation circuit. Hot energy of a warm head of the Sterling refrigerating machine is discharged to the outside of a cooling chamber by a high-temperature-side first circulation circuit. A portion of the hot energy is transmitted to a condensation prevention section of a cooling chamber wall via a high-temperature-side second circulation circuit. In the high-temperature-side second circulation circuit are provided a circulation pump for circulating a secondary refrigerant sealed in the circuit and a heat exchanger exposed to the outside. At the time of defrosting of the low-temperature-side circulation circuit, a control section stops operation of the Sterling refrigerating machine while continuing operation of the circulation pump.

Description

Specification

Refrigerator

Technical field

[0001] The present invention relates to a refrigerator equipped with a Stirling refrigerator. “Refrigerator” is a concept that refers to all devices that lower the temperature of food and other items, regardless of its name as “refrigerator”, “freezer”, “freezer refrigerator”, “showcase” t ,.

Background art

[0002] In the refrigeration cycle of the refrigerator, specific chlorofluorocarbon (CFC: chlorofluorocarbon) or alternative chlorofluorocarbon (HCFC: hydrochlorofluorocarbon, HFC: hydrofluorocarbon) is used as a refrigerant. Among these refrigerants, CFCs and HCFCs are subject to international regulations for their production and use because they, when released to the atmosphere, cause the destruction of the ozone layer to some extent. Another problem is that HFCs that do not destroy the ozone layer also promote global warming.

[0003] Therefore, a Stirling refrigerator that does not use an ozone depleting substance as a refrigerant is in the spotlight. In a Stirling refrigerator, an inert gas such as helium is used as a working medium, and the piston and displacer are operated by external power to repeatedly compress and expand the working medium. This raises the temperature of the worm head (heat dissipating part) and lowers the temperature of the cold head (heat absorbing part). The warm head dissipates heat to the surrounding environment, and the cold head absorbs heat from the interior.

[0004] When performing heat dissipation and heat absorption in a Stirling refrigerator, a thermosiphon using brine (liquid used as a heat transport medium) as a secondary refrigerant is often used. In other words, a high-temperature side evaporator is attached to the worm head, and the secondary refrigerant in it is evaporated with warm heat. The evaporated secondary refrigerant is sent to the high temperature side condenser, where it is restored to a liquid and returned to the high temperature side evaporator. A cold side condenser is attached to the cold head, and the secondary refrigerant in it is condensed with cold heat. The condensed secondary refrigerant is sent to the low temperature side evaporator, where it is restored to gas and returned to the low temperature side condenser.

[0005] As described above, Patent Document 1 shows an example of a refrigerator that uses a thermosyphon to transmit the heat and cold of a Stirling refrigerator. In the refrigerator of Patent Document 1, Refrigerant power The refrigerant that has received the heat is led to the dew-proofing part of the cooling wall (opening part of the cooling chamber) by piping so that the temperature of the dew-proofing part does not drop below the dew point.

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-20056

Disclosure of the invention

Problems to be solved by the invention

[0006] Frost adheres to the low-temperature side evaporator that cools the inside of the power chamber, which is the same as in general refrigerators. Frost increases in thickness over time and reduces cooling capacity. Therefore, it is necessary to stop the refrigerator regularly and defrost.

[0007] When a Stirling refrigerator is used as the refrigerator, neither hot nor cold is produced during operation stop. Therefore, in the case where the dew proof part is heated with heat like the refrigerator described in Patent Document 1, the dew proof part gradually cools during the defrost period (60 to 90 minutes are consumed). In particular, an opening in a cooling space with a low temperature such as a freezing room easily falls below the dew point. If dew condensation occurs at every defrosting, the wall of the refrigerator is generated earlier and the commercial value is impaired.

[0008] When considering the brine, there is almost no need to worry about freezing of the cold transport brine used to generate a low temperature of minus 40 ° C. However, there is concern about freezing of brine for thermal transport. This is because in order to increase the amount of heat transferred by the brine circulation, it is necessary to increase the circulation amount of the brine. If it is high, the circulation rate decreases, so the viscosity of the brine must be kept low. If the brine is a mixture of water and antifreeze, the antifreeze is generally more viscous than water, so if you want to reduce the viscosity of the brine to ensure circulation, you should reduce the antifreeze mix ratio. I do not get. As a result, the brine freezes at a relatively high temperature. The brine easily freezes when some of the conditions are met, such as the inside temperature is low, the outside temperature is low, the Stirling refrigerator is stopped and the heat source is turned off, or the brine is also stopped. Striped

[0009] The present invention has been made to address the above problems, and in a refrigerator having a configuration in which a part of the heat of the warm head of the Stirling refrigerator is transmitted to the dew-proof portion of the refrigerator wall. The object is to provide a structure that can prevent dew condensation even during the period when one ring refrigerator is stopped. In addition, in a refrigerator that uses a Stirling refrigerator to transfer heat through brine circulation, a refrigerator that can effectively prevent freezing even if it is necessary to use brine with a high freezing point. The purpose is to provide.

Means for solving the problem

[0010] In order to achieve the above object, the present invention provides a low-temperature side circulation circuit for transmitting the cold heat of the cold head of the Stirling refrigerator to the cooling space via the low-temperature evaporator, and the heat of the warm head of the Stirling refrigerator. A high-temperature side first circulation circuit that radiates heat to the outside of the cabinet, and a high-temperature side second circulation circuit that transmits a part of the heat to the dew-proof portion of the refrigerator wall, wherein the high-temperature side second circulation circuit A circulation pump is provided for circulating the refrigerant enclosed in the heat exchange section exposed to the outside, and the circulation pump is operated during defrosting of the low-temperature side evaporator.

[0011] According to this configuration, even when the heat of the worm head of the Stirling refrigerator is not dissipated, operating the circulation pump causes the refrigerant in the high-temperature side second circulation circuit to flow and exchange heat. The outside heat is taken in at the section. Since the heat is transferred to the dew condensation part, the time when the temperature of the dew condensation part falls below the condensation point is delayed. Or it can be prevented from dropping below the dew point.

[0012] The present invention is characterized in that, in the cooler configured as described above, in the high temperature side second circulation circuit, the heat exchange part is formed on the downstream side of the dew prevention part.

[0013] According to this configuration, during operation of the Stirling refrigerator, the refrigerant in the high-temperature side second circulation circuit first transmits the heat to the dew proof part and passes through the heat exchange part. It is possible to heat it.

[0014] The present invention is characterized in that, in the cooler configured as described above, the heat exchanging portion exchanges heat with the drain in the drain pan.

[0015] According to this configuration, it is possible to prevent condensation by transmitting the heat held by the drain to the dew proofing unit. Heat exchange efficiency is good because heat is exchanged with liquid drain.

[0016] The present invention is characterized in that in the cooler configured as described above, a blower that blows air through the heat exchange unit is provided, and the blower is operated together with the circulation pump during a defrost period. The

[0017] According to this configuration, by blowing air through the heat exchanging unit that merely exposes the heat exchanging unit, the heat of the outside air is positively received by the high-temperature side second circulation circuit, and the dew preventing unit We can secure the heat to convey.

[0018] The present invention is characterized in that, in the cooler configured as described above, the blower is provided for heat dissipation of the high temperature side first circulation circuit.

According to this configuration, since the blower provided for heat dissipation of the high temperature side first circulation circuit is also used for heat reception of the high temperature side second circulation circuit, the cost of additionally installing the blower becomes unnecessary. Further, during operation of the Stirling refrigerator, the heat from the high temperature side first circulation circuit is received by the high temperature side second circulation circuit, and the refrigerant in the high temperature side second circulation circuit can be sufficiently heated.

[0020] The present invention provides a low temperature side circulation circuit that transmits cold heat of a cold head of a Stirling refrigerator to a cooling space by brine circulation, and a high temperature side circulation circuit that dissipates heat of the warm head of the Stirling refrigerator by brine circulation. In a refrigerator equipped with a control unit that performs overall control, a circulation pump is provided in the high temperature side circulation circuit, an environmental temperature sensor is provided in a passage path of the high temperature side circulation circuit, and the control unit The circulating pump is operated even when the Stirling refrigerator is stopped when the temperature detected by the environmental temperature sensor becomes a predetermined value or less.

[0021] According to this configuration, when the temperature detected by the environmental temperature sensor falls below a predetermined value, the circulation pump is operated even when the staring refrigerator is stopped, and the brine in the high-temperature side circulation circuit is circulated. Therefore, even if the high-temperature side circulation circuit is exposed to a low temperature below the freezing point of the brine, the freezing of the brine can be prevented by the flow of the brine.

[0022] The present invention is characterized in that, in the cooler configured as described above, the operation of the circulating pump while the Stirling refrigerator is stopped is an intermittent operation.

[0023] According to this configuration, the brine can be flowed to such an extent that the brine does not freeze, and less power is consumed than when the circulating pump is operated continuously. Also, since the operation time of the circulation pump is not prolonged, the pump life can be extended.

[0024] According to the present invention, in the cooler configured as described above, a circuit temperature sensor is provided in the high temperature side circulation circuit, and the temperature is lower than the freezing point of the brine enclosed in the high temperature side circulation circuit!ヽ The temperature is the environmental temperature When the temperature sensor detects 1, the circulating pump is started at the timing when the circuit temperature sensor detects a temperature rise due to the start of freezing of the brine.

[0025] Brine that is not flowing becomes supercooled when exposed to low temperatures below the freezing point. When subcooling progresses to some extent, the brine begins to freeze, releasing latent heat as the phase transitions from the liquid phase to the solid phase. Therefore, the temperature of the high-temperature side circulation circuit rises temporarily. Since the circulation pump is started at the timing when the circuit temperature sensor detects this temperature rise, the circulation is started at the last minute timing when the brine freezes and the circulation becomes impossible if it is delayed further, and the operation rate of the circulation pump is reduced. Energy loss can be minimized.

[0026] The present invention is characterized in that, in the cooler configured as described above, the environmental temperature sensor is provided at a location where cold heat is transmitted from within the cooler.

[0027] According to this configuration, the circulating pump is operated when the environmental temperature sensor detects that the temperature of the location has become a predetermined value or less due to the cold heat transmitted from the inside of the refrigerator, so that the brine is generated by the cold heat in the refrigerator. The situation of freezing can be avoided.

[0028] In the refrigerator having the above configuration, the high temperature side circulation circuit includes a high temperature side first circulation circuit that radiates the heat of the warm head of the Stirling refrigerator to the outside of the refrigerator, and the one of the heat. A high-temperature side second circulation circuit that conveys the heat to the dew-proof part of the refrigerator, and the circulation pump and the environmental temperature sensor are provided for the high-temperature side second circulation circuit

[0029] The dew-proof portion of the refrigerator includes the vicinity of the freezer compartment. Needless to say, the freezer compartment is cold, so the dew-proof part is often quite cold. Since the circulation pump and the environmental temperature sensor are provided for the high-temperature side second circulation circuit passing through the dew protection section, it is possible to avoid brine freezing in the high-temperature side second circulation circuit due to the low temperature of the freezer compartment.

[0030] The present invention is characterized in that, in the cooler configured as described above, an exposed heat radiating portion is provided in a part of the second high-temperature side circulation circuit.

[0031] According to this configuration, it is possible to apply the heat of the outside air to the high temperature side second circulation circuit at the exposed heat radiating portion so that the brine in the high temperature side second circulation circuit does not fall to a temperature below the freezing point. it can [0032] The present invention is characterized in that, in the cooler configured as described above, the environmental temperature sensor is provided in the exposed heat radiating portion.

[0033] According to this configuration, when the temperature of the outside air falls below a predetermined value, the circulation pump can be operated to cause the brine to flow, so that the brine does not freeze.

The present invention is characterized in that, in the cooler having the above-described configuration, a blower is provided in the exposed heat radiating portion, and the blower operates in conjunction with the operation of the circulation pump.

According to this configuration, when the circulation pump is operated, the outside air is blown to the exposed heat radiating portion by the blower. Therefore, the outside air is positively given to the high temperature side second circulation circuit, and the inside of the high temperature side second circulation circuit is activated. It can be ensured that the brine does not drop below the freezing point.

The invention's effect

[0036] According to the present invention, even in a situation where the heat of the worm head of the Stirling refrigerator is not dissipated, heat is taken into the second circulation circuit on the high temperature side from other heat sources to suppress dew condensation in the dew proof part. You can prevent it!

[0037] Further, according to the present invention, when the temperature of the environment surrounding the high-temperature side circulation circuit is detected by the environmental temperature sensor and shows a value equal to or lower than a predetermined value, the circulation pump is operated even when the Stirling refrigerator is stopped. Then, since the brine in the high-temperature side circulation circuit is circulated, even if the high-temperature side circulation circuit is exposed to a low temperature below the brine freezing point, the brine can be prevented from freezing.

Brief Description of Drawings

[0038] [Fig.1] Vertical section of the refrigerator

[Figure 2] Schematic configuration diagram of cooling cycle

[Fig.3] Schematic cross section of heat exchanger

FIG. 4 is a perspective view illustrating the piping path of the high-temperature side second circulation circuit.

[Fig.5] Cross section of the evaporator in the first circulation circuit on the high temperature side

FIG. 6 is a schematic configuration diagram of a cooling cycle according to a second embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a cooling cycle according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a cooling cycle according to a fourth embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of a cooling cycle according to a fourth embodiment of the present invention. [Fig. 10] Graph of temperature change due to circulation pump operation 圆 11] Explanation of symbols in experimental data on surface temperature of dew-proof pipe

1 Refrigerator

10 Insulated housing

13 Control unit

20 Cold room

30 Freezer

40 Machine room

50 Stirling refrigerator

51 Worm head

52 = 3—Nored, head,

60 High-temperature side first circulation circuit

61 Hot side evaporator

62 Hot side condenser

64G gas phase refrigerant piping

64L liquid refrigerant piping

70 Low-temperature side circulation circuit

71 Low temperature side condenser

72 Low temperature evaporator

74 Defrost heater

91 Blower

100 High temperature side second circulation circuit

101 heat exchanger

103, 105 Heat exchanger

104 Blower

110 Circulation pump

120 Dew protection section 132 Drain non

141, 142 Ambient temperature sensor

143 Circuit temperature sensor

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a first embodiment of the present invention will be described with reference to FIG. The refrigerator 1 is for food preservation, and a heat insulating housing 10 supported on the floor by a base 12 constitutes the main body. The cooling space inside the heat insulating housing 10 is divided into two stages, upper and lower, by a horizontal partition wall 11, and the upper stage is set as a refrigerator compartment 20 and the lower stage is set as a freezer compartment 30. In both the refrigerator compartment 20 and the freezer compartment 30, the front surface (left side in FIG. 1) is an opening for putting food in and out, and the heat insulating doors 21 and 31 are closed.

A machine room 40 is formed on the back surface of the heat insulating housing 10. The machine room 40 is a rectangular parallelepiped structure configured by combining sheet metal parts, and the back side is open. A Stirling refrigerator 50 is installed in the machine room 40. The machine room 40 is located at a height between the refrigerator room 20 and the freezer room 30.

[0042] After the Stirling refrigerator 50 is installed, the rear side opening of the machine room 40 is closed with the lid 44. The lid 44 is formed with a vent 45 for taking in air for cooling the high-temperature side condenser, which will be described later, and an opening 47 for discharging air deprived of heat from the high-temperature side condenser.

[0043] The Stirling refrigerator 50 generates heat and cold by a reverse Stirling cycle. The heat is dissipated mainly from the warm head 51 (see FIG. 2) as waste heat, and the cold is taken out from the cold head 52.

[0044] It is the high-temperature side first circulation circuit 60 that extracts the heat from the worm head 51 and dissipates it. The high temperature side first circulation circuit 60 is obtained by enclosing a secondary refrigerant 63 (see FIG. 5) in a closed system in which a high temperature side evaporator 61 and a high temperature side evaporator 62 are connected by a refrigerant pipe. The secondary refrigerant 63 is water (including an aqueous solution) or a hydrocarbon-based brine. “Secondary refrigerant” is defined by defining the working medium inside Stirling refrigerator 50 as “primary refrigerant” and the working medium used for heat transfer outside Stirling refrigerator 50 as “secondary refrigerant”. . Incidentally, the “tertiary refrigerant” described later is a refrigerant that exchanges heat with the secondary refrigerant.

[0045] The high temperature side evaporator 61 is made of a metal having good thermal conductivity such as copper, copper alloy, and aluminum in a hollow ring shape. The worm head 51 is molded, fitted to the outer peripheral surface of the worm head 51, and thermally connected to the worm head 51. Two refrigerant pipes connected to the high temperature side condenser 62 are drawn out from the upper surface of the high temperature side evaporator 61. One refrigerant pipe is a gas-phase refrigerant pipe 64G that sends the secondary refrigerant 63 evaporated to gas to the high-temperature side condenser 62. The other refrigerant pipe is a liquid-phase refrigerant pipe 64L that returns the secondary refrigerant 63 condensed into a liquid by the high-temperature side condenser 62 to the high-temperature side evaporator 61.

[0046] The high-temperature side condenser 62 bends a pipe 62a having good heat conduction and metal power, such as copper, copper alloy, and aluminum, and is attached with a number of heat radiation fins 62b having metal power also having good heat conduction. Structure. A gas phase refrigerant pipe 64G is connected to one end of the high temperature side condenser 62, and a liquid phase refrigerant pipe 64L is connected to the other end.

A cold side condenser 71 is attached to the cold head 52. The cold head 52 and the low-temperature side condenser 71 are in a state of transferring heat between them, that is, in a state of being thermally connected.

[0048] A low-temperature evaporator 72 that functions as an internal cooler for cooling the interior of the refrigerator 30 is installed in the back of the freezer compartment 30. The low temperature side condenser 71 and the low temperature side evaporator 72 are connected by a pipe 73 to constitute a low temperature side circulation circuit 70. The low-temperature side circulation circuit 70 is filled with natural refrigerant such as C02 as brine.

[0049] Similarly to the high-temperature side condenser 62, the low-temperature side evaporator 72 also has a large number of endotherms that also have a metal power with a good heat conductivity after bending a pipe 72a with a metal power with a good heat conductivity such as copper, copper alloy, and aluminum. A structure with fins 72b attached. A defrost heater 74 is attached to the low temperature side evaporator 72.

[0050] At the lower end of the cooling duct 80, there is provided an air inlet 82 for sucking and taking in the internal air from the freezer compartment 30. A low-temperature side evaporator 72 is installed above the intake port 82, and a blower 83 that blows out air to the cooling duct 81 is further provided above the low-temperature side evaporator 72.

When the Stirling refrigerator 50 is operated, the worm head 51 becomes high temperature and the cold head 52 becomes low temperature. The heat of the worm head 51 is the waste heat that should be dissipated to the outside. This is because the secondary refrigerant 63 in the high-temperature side first circulation circuit 60 evaporates and resides in the gas of the secondary refrigerant 63 as latent heat, When the secondary refrigerant 63 condenses in the side condenser 62, it is released as sensible heat and dissipated into the environment. The cold heat of the cold head 52 is transmitted to the low temperature side evaporator 72 via the low temperature side circulation circuit 70. When the blower 83 is operated, air in the freezer compartment 30 is sucked from the inlet 82 at the lower end of the cooling duct 80 and passes through the low-temperature side evaporator 72. Further, through the return duct (not shown), the air in the refrigerator compartment 20 is sucked into the cooling duct 80 and also passes through the low temperature side evaporator 72. When passing through the low temperature side evaporator 72, the air is cooled and becomes cold.

[0053] The cold air is blown into the cooling duct 81 by the blower 83, and enters the refrigerating chamber 20 through the air outlet 84 provided in the upper part of the cooling duct 81 (the part above the horizontal partition wall 11) and the cooling duct 81. Each is sent into the freezer compartment 30 through the outlet 85 provided in the lower part (the part below the horizontal partition wall 11). In this manner, a predetermined amount of cold air is fed into the refrigerator compartment 20 and the freezer compartment 30 and cooled to a predetermined temperature. The control unit 13 installed at the upper back of the heat insulating housing 10 controls the above operation control.

[0054] The hot heat taken out from the worm head 51 by the high temperature side first circulation circuit 60 is also used to prevent dew condensation in the dew proof part. This is realized by the high-temperature side second circulation circuit 100.

The high temperature side second circulation circuit 100 is thermally connected to the gas phase refrigerant pipe 64G of the high temperature side first circulation circuit 60 via the heat exchanger 101. As shown in FIG. 3, the jacket 102 is provided in a part of the gas-phase refrigerant pipe 64G, and the heat exchanger 101 is configured by passing the pipe 106 of the high-temperature side second circulation circuit 100 therein. The pipe 106 meanders inside the jacket portion 102 so as to receive a lot of heat from the vaporized secondary refrigerant 63.

[0056] The high temperature side second circulation circuit 100 is filled with brine as a tertiary refrigerant in a non-depressurized state. As the brine, for example, a mixed solution of 85% water and 15% ethyl alcohol is used.

The second high-temperature side circulation circuit 100 exits the heat exchanger 101 and then follows the path shown in FIG. That is, the high-temperature side second circulation circuit 100 passes through the bottom surface of the machine room 40, changes the rearward direction toward the bottom of the heat insulating housing 10, and reaches the lower left edge of the opening of the freezing room 30. In this specification, the left side of the observer facing the front surface of the thermal insulation case 10 is defined as the left side of the heat insulation case 10, and the right side of the observer is defined as the right side of the heat insulation case 10. The second circulation circuit 100 on the high temperature side also follows the opening at the left edge of the freezing chamber 30 from the left edge to the upper edge of the freezing chamber 30 and then the opening of the refrigerator compartment 20 from the lower edge to the left edge → Go round from the top edge to the right edge. Then, the high-temperature side second circulation circuit 100 goes from the right edge to the lower edge of the freezer compartment 30 and then comes out under the bottom wall of the heat insulating casing 10. High temperature here The second side circulation circuit 100 meanders and constitutes the heat exchange unit 103 exposed to the outside. Thereafter, the high-temperature side second circulation circuit 100 returns to the heat insulating casing 10, and returns to the heat exchanger 101 through the circulation pump 110.

In this embodiment, the dew proof part is the opening of the refrigerator compartment 20 and the freezer compartment 30. In Fig. 2, the dew protection part 120 is symbolized by a broken rectangle.

When the operation of the refrigerator 1 is continued, the moisture in the air in the refrigerator becomes frost and adheres to the low temperature side evaporator 72. The frost reduces the heat exchange efficiency of the low-temperature evaporator 72. Therefore, the control unit 13 stops the operation of the Stirling refrigerator 50 at an appropriate timing and energizes the defrost heater 74 to perform defrosting. Drain generated by melting frost is received by the drain receiver 130 at the bottom of the cooling duct 80, and is drained outside the chamber through the drainage pipe 131.

A drain pan 132 for storing drain dripping from the drain pipe 131 is installed under the bottom wall of the heat insulating casing 10. The drain pan 132 can be pulled out from the front side of the refrigerator 1 in order to discard the drain accumulated in the drain pan 132.

[0061] The lower surface of the drain pan 132 is in contact with the heat exchange unit 103. During the operation of the Stirling refrigerator 50, the drain pan 132 and the drain therein are heated by the warm heat carried by the tertiary refrigerant in the high-temperature side second circulation circuit 100, and the temperature rises. For this reason, the evaporation of the drain is promoted, and the time and effort for discarding the drain can be reduced.

[0062] As described above, the controller 13 stops the operation of the Stirling refrigerator 50 during the defrosting of the low-temperature side evaporator 72 that is a component of the low-temperature side circulation circuit 70. Therefore, the dew-proof part 120 that has been heated until then gradually cools. On the other hand, the control unit 13 continues the operation of the circulation pump 110. As a result, the tertiary refrigerant in the high temperature side second circulation circuit 100 flows and exchanges heat with the outside at the heat exchange unit 103. In the case of the first embodiment, the atmosphere outside the machine and the drain in the drain pan 132 are heat exchange targets of the heat exchange unit 103.

[0063] Atmosphere and drain force The obtained heat is provided to the dew proof part 120, so that the time when the temperature of the dew proof part 120 falls below the dew point can be delayed. Thereby, the dew condensation of the dew proof part 120 is suppressed and prevented.

[0064] The heat exchange unit 103 is formed on the downstream side of the dew proof unit 120. Therefore, during the operation of the Stirling refrigerator 50, the tertiary refrigerant in the high-temperature side second circulation circuit 100 is first transferred to the dew protection section 120. The heat is transmitted and the force passes through the heat exchanging unit 103, so that the dew proof unit 120 is reliably heated.

[0065] Further, since the heat exchanging unit 103 exchanges heat with the drain in the drain pan 132, the heat held by the drain can be effectively utilized. The drainage of frost and ice that has melted on the low-temperature evaporator 72 rises to a level equivalent to the outside air temperature while accumulating in the drain pan 132 over a long period of time, so it can be used as a heat source. It becomes possible. Heat exchange efficiency is also good because heat is exchanged with liquid drain. In the first embodiment, a configuration in which the heat exchanging portion 103 is immersed in a force drain that makes heat exchange with the drain by bringing the heat exchanging portion 103 into contact with the lower surface of the drain pan 132 is also possible.

A second embodiment of the present invention is shown in FIG. A feature of the second embodiment is that a blower 104 that blows air through the heat exchange unit 103 is provided for the heat exchange unit 103, and the blower 104 is operated together with the circulation pump 110 during the defrosting period. is there. In this way, by blowing air through the heat exchanging unit 103 that merely exposes the heat exchanging unit 103 to the outside, the heat of the outside air is positively received by the second circulation circuit 100 on the high temperature side, and the dew preventing unit The heat transmitted to 120 can be secured. As with the high temperature side condenser 62 and the low temperature side evaporator 72, fins may be provided in the heat exchange unit 103.

A third embodiment of the present invention is shown in FIG. In the third embodiment, the second heat exchange unit 105 is formed in the high temperature side second circulation circuit 100. The heat exchanging unit 105 is further downstream of the heat exchanging unit 103 and is arranged on the blowout side of the blower 91 for forced air cooling of the high temperature side condenser 62. The blower 91 is operated together with the circulation pump 110 during the defrosting period. As a result, the heat of the outside air can be positively received by the high-temperature side second circulation circuit 100, and the heat transferred to the dew protection unit 120 can be secured. As with the high temperature side condenser 62 and the low temperature side evaporator 72, a fin may be provided in the heat exchanging section 105.

[0068] In the configuration of the third embodiment, since the fan 91 provided for heat dissipation of the high temperature side first circulation circuit 60 is also used for heat reception of the high temperature side second circulation circuit 100, the high temperature side second circuit is used. Costs can be reduced by eliminating the need for a dedicated blower for the circulation circuit. In addition, during operation of the Stirling refrigerator 50, the heat from the high-temperature side condenser 62 is received by the high-temperature side second circulation circuit 100, and the tertiary refrigerant in the high-temperature side second circulation circuit 100 can be sufficiently heated. it can.

[0069] A fourth embodiment of the present invention is shown in FIGS. 8-11. The feature of the fourth embodiment is high The temperature of the environment surrounding the second circulating circuit 100 on the warm side is detected by an environmental temperature sensor, and operation control is performed such that the brine in the second circulating circuit 100 on the high temperature side is not frozen.

FIG. 8 shows a state where the cooling cycle is viewed from the back side of the refrigerator 1. The heat-insulating housing 10 is represented by a virtual line, but only the machine room 40 at the upper back is drawn by a solid line.

[0071] Brine is sealed in the high temperature side second circulation circuit 100 in a non-depressurized state. This brain is a mixture of water and antifreeze, and it is necessary to make the viscosity low to secure the circulation rate, so the mix ratio of antifreeze is low. Therefore, the freezing point of brine is relatively high.

[0072] After exiting the heat exchanger 101, the pipe 106 of the high temperature side second circulation circuit 100 follows the path shown in FIG. That is, the pipe 106 enters the circulation pump 110 through the gas-liquid separator 107. The pipe 106 exiting the circulation pump 110 passes through the bottom surface of the machine room 40 to become a down pipe 106D, and descends in the rear wall of the heat insulating housing 10. The pipe 106 that reaches the lower part of the rear wall enters the lower part of the right side wall of the heat insulating casing 10, passes forward, and reaches the lower front part of the insulating casing 10. The pipe 106 then folds to the center side of the heat insulating housing 10 and reaches the vertical partition wall (not shown) including the one described later before the front edge of the vertical partition wall. After the meandering of the front edge of the two-stage horizontal partition wall that divides the freezer compartment into the left half of the heat insulation case 10 and the left half of the heat insulation case 10, and the lower part of the left side wall of the heat insulation case 10 Ascend the edge and force it through the front edge of the ceiling wall from left to right, and then descend the front edge of the right wall. On the way down the front edge of the right side wall, the pipe 106 snakes into the horizontal partition wall that partitions the freezer compartment in the right half of the heat insulating casing 10.

[0073] The pipe 106 reaching the lower part of the right side wall exits to the heat exchanging part 103 set below the bottom of the heat insulating casing 10. The pipe 106 meanders at the heat exchanging portion 103 while directly contacting the outside air, and dissipates heat to the outside air. If the drain pan 132 is placed on the heat exchange unit 103, the drain pan 132 and the drain therein are heated, and the evaporation of the drain is promoted. The blower 104 blows wind against the pipe 106 in the heat exchange unit 103.

[0074] The pipe 106 that has passed through the heat exchanging section 103 enters the back wall of the heat insulating casing 10, rises into the back wall as an up pipe 106U, and returns to the machine room 40. Then return to heat exchange 101.

[0075] The pipe 106 passes through a portion close to the surface of the heat insulating casing 10 on the front and left and right side walls of the heat insulating casing 10. These places become the dew proof part 120 shown in FIG. Carried by pipe 106 The waste heat of the Stirling refrigerator 50 can be used not only to prevent condensation in the dew proofing unit 120 but also to promote drain evaporation as described above.

The control unit 13 is in charge of overall control of the refrigerator 1. Signals are transmitted from the environmental temperature sensors 141 and 142 and the circuit temperature sensor 143 to the control unit 13. The environmental temperature sensor 141 is arranged in the dew proof part 120 where the cold heat in the freezer compartment is easily transmitted. Then, a circuit temperature sensor 143 is provided at a position where the surface temperature of the pipe 106 passing through the location can be measured. The environmental temperature sensor 142 is disposed in the heat exchange unit 103 so as to be exposed to the outside air.

[0077] Circulation pump 110 is operated in conjunction with operation of Stirling refrigerator 50. Even when the Stirling refrigerator 50 is stopped, the control unit 13 operates the circulation pump 110 if predetermined conditions are met. The conditions will be described below.

The first condition is “environmental temperature sensor 141 detects a temperature equal to or lower than a predetermined value”. The “predetermined value” is set at or near the freezing point of the brine. As a result, it is detected that the brine in the high temperature side second circulation circuit 100 is nearing the risk of freezing, and the circulation pump 110 is activated.

The second condition is “environmental temperature sensor 142 detects a temperature equal to or lower than a predetermined value”. The “predetermined value” is set at or near the freezing point of the brine. As a result, it is detected that the brine in the high temperature side second circulation circuit 100 is nearing the risk of freezing, and the circulation pump 110 is activated.

[0080] The third condition is “when the environmental temperature sensor 141 or the environmental temperature sensor 142 detects a temperature lower than the freezing point of the brine, the circuit temperature sensor 143 detects the temperature increase of the pipe 106”. It is. Non-flowing brine will be supercooled before freezing when exposed to low temperatures below the freezing point. The brine begins to freeze when the supercooling progresses to some extent, but the brine containing the antifreeze component is in the form of a slurry in the vicinity of the freezing point and has sufficient fluidity to circulate. During this freezing, the brine releases latent heat as the liquid phase transforms into the solid phase. Therefore, the temperature of the pipe 106 of the high-temperature side second circulation circuit 100 temporarily rises. When the circuit temperature sensor 143 detects this temperature rise, the circulation pump 110 is activated to circulate the brine, and the brine is completely melted by the circulation. In this way, if it is delayed further, the brine will freeze and become impossible to circulate. Circulation can be started, the operation rate of the circulation pump 110 can be suppressed, and the energy loss can be minimized.

[0081] When the circulation pump 110 is operated while the Stirling refrigerator 50 is stopped, the operation is an intermittent operation. By doing so, the brine can be flowed to such an extent that the brine does not freeze, and less power is consumed than when the circulation pump 110 is operated continuously. In addition, since the operation time of the circulation pump 110 is not prolonged, the pump life can be extended. The circulation pump 110 is temporarily stopped when the Stirling refrigerator 50 is stopped, and then intermittent operation is started.

FIG. 10 shows an actual example of the temperature change in the dew proof portion when the circulation pump is intermittently operated. If the Stirling refrigerator is stopped and left as it is, the surface temperature of the dew protection pipe (pipe 106 in Fig. 9) that is cooled by the cold heat in the freezer compartment will continue to drop, but the circulation pump will If intermittent operation is performed, the surface temperature of the dew protection pipe (solid line) rises intermittently, and the surface temperature of the dew prevention part (broken line) also rises intermittently. In the example of Fig. 10, when the freezer is set to minus 40 ° C at an outside air temperature of 5 ° C, and the circulation pump is intermittently operated at a cycle of 5 minutes for 15 minutes after the Stirling refrigerator is stopped, In other words, the surface temperature of the pipe 106) in the dew proof part 120 has been successfully maintained at minus 5-6 ° C or higher.

[0083] Regardless of the circuit temperature sensor 143, the freezing room temperature detected by the environmental temperature sensor 141 and the outside air temperature detected by the environmental temperature sensor 142 are multiplied by a regression equation so that the surface temperature of the pipe 106 is obtained with a certain degree of accuracy. It is possible to ask. Fig. 11 shows an example of the correlation between the measured temperature and the regression equation. The temperature unit is “de”. Here, the following regression equation was used.

0. 23 X (outside temperature) +0. 39 X (freezer temperature) -5. 7

As seen in Fig. 11, the correlation between the measured value and the regression calculation value is high.

[0084] When the outside air temperature is considerably higher than the freezing point of the brine (FIG. 11 also corresponds to this), when the circulation pump 110 is operated, heat from the outside air is given to the high-temperature side second circulation circuit 100 by the heat exchange unit 103. It is done. This heat helps to prevent the brine in the second circulating circuit 100 on the high temperature side from dropping below the freezing point. At this time, if the blower 104 is operated in conjunction with the operation of the circulation pump 110, the heat of the outside air can be transmitted to the high-temperature side second circulation circuit 100 better. [0085] The presence of the heat exchange unit 103 is also useful in that it enables intermittent operation of the circulation pump 110. In other words, if the circulation pump 110 is operated under the condition that the brine in the high-temperature side second circulation circuit 100 that the heat exchanging unit 103 passes only through the location where it receives cold from the freezer compartment, the power of the brine continues to be deprived of heat. Becomes stable at a low temperature and the circulation pump 110 cannot be stopped. This is because if the circulation pump 110 is stopped in such a state, the brine immediately freezes. Even if the circulation pump 110 is successfully stopped without freezing the brine, the brine will be shocked and frozen this time when the circulation pump 110 is started. If the heat exchanging section 103 is provided, the temperature of the brine can be raised by the heat of the outside air, so that it is not necessary to lower the temperature of the brine until the above situation is reached. That is, the circulating pump 110 can be intermittently operated.

As described above, each embodiment of the present invention has been described, but the scope of the present invention is not limited to this, and various modifications can be implemented without departing from the spirit of the invention. .

Industrial applicability

[0087] The present invention can be widely used in a refrigerator in which a Stirling refrigerator is mounted and a part of waste heat of the Stirling refrigerator is used for preventing condensation.

Claims

The scope of the claims

[1] A low-temperature side circulation circuit that transmits the cold heat of the Stirling refrigerator cold head to the cooling space via the low-temperature evaporator, and the high-temperature side No. 1 that releases the warm heat of the Stirling refrigerator warm head to the outside. In a refrigerator having a circulation circuit and a high-temperature side second circulation circuit that transfers a part of the heat to a dew-proof portion of the refrigerator wall,

A circulation pump that circulates the refrigerant sealed in the high-temperature side second circulation circuit through a heat exchange section exposed to the outside is provided, and the circulation pump is operated during defrosting of the low-temperature side evaporator. And a refrigerator.

[2] The refrigerator according to claim 1, wherein in the high temperature side second circulation circuit, the heat exchange part is formed downstream of the dew prevention part.

[3] The refrigerator according to claim 1, wherein the heat exchanging section exchanges heat with the drain in the drain pan.

[4] The refrigerator according to claim 1, wherein a blower that blows air through the heat exchange unit is provided, and the blower is operated together with the circulation pump during a defrosting period.

5. The refrigerator according to claim 4, wherein the blower is provided for heat dissipation of the high temperature side first circulation circuit.

[6] A low temperature side circulation circuit that transmits the cold heat of the Stirling refrigerator cold head to the cooling space through brine circulation, a high temperature side circulation circuit that dissipates the heat of the warm head of the Stirling refrigerator through brine circulation, and overall control. In a refrigerator having a control unit that manages, a circulation pump is provided in the high temperature side circulation circuit, an environmental temperature sensor is provided in a passage path of the high temperature side circulation circuit, and the control unit detects a temperature detected by the environmental temperature sensor. When the temperature becomes below a predetermined value, the circulating pump is operated even if the Stirling refrigerator is stopped.

7. The refrigerator according to claim 6, wherein the operation of the circulating pump while the Stirling refrigerator is stopped is an intermittent operation.

[8] A circuit temperature sensor is provided in the high temperature side circulation circuit, and when the ambient temperature sensor detects a temperature lower than the freezing point of the brine enclosed in the high temperature side circulation circuit, the At the timing when the circuit temperature sensor detects a temperature rise due to the start of freezing. The refrigerator according to claim 6 or 7, wherein a ring pump is activated.

[9] The refrigerator according to any one of claims 6 to 8, wherein the environmental temperature sensor is provided at a location where cold heat is transmitted from the inside of the refrigerator.

[10] The high temperature side circulation circuit includes a high temperature side first circulation circuit that dissipates the heat of the worm head of the Stirling refrigerator to the outside of the chamber, and a high temperature side first circuit that transmits a part of the heat to the dewproof part of the refrigerator. The refrigerator according to any one of claims 6 to 9, comprising a circulation circuit, wherein the circulation pump and an environmental temperature sensor are provided for the second high-temperature side circulation circuit.

11. The refrigerator according to claim 10, wherein an exposed heat radiating portion is provided in a part of the high temperature side second circulation circuit.

12. The environmental temperature sensor is provided in the exposed heat radiation part.

The refrigerator according to 11.

13. The refrigerator according to claim 11, wherein a fan is provided in the exposed heat radiating section, and the fan operates in conjunction with the operation of the circulation pump.