JP3020728B2 - Electronic refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic refrigerator in which the inside of a refrigerator is cooled by the thermoelectric conversion of a thermoelectric element.

[0002]

2. Description of the Related Art In recent years, in a refrigerator for a hospital room or a hotel, for example, a thermoelectric element is used in place of a refrigeration cycle as a cooling source in order to satisfy a demand for low noise and compactness due to the special location of the installation place. The used electronic refrigerator is in the spotlight.

A conventional electronic refrigerator is disclosed in, for example,
As shown in Japanese Patent Application Laid-Open No. 099771, a thermoelectric element is disposed on the rear heat insulating wall of the refrigerator body, and an aluminum heat exchanger is provided on each of a heat absorbing surface (inside the refrigerator) and a heat radiation surface (outside the refrigerator) of the thermoelectric device. It is configured to be in contact. In this case, when a current flows, the thermoelectric element generates a phenomenon in which heat is absorbed from the heat absorbing surface by the Peltier effect and the heat is released from the heat radiating surface. The heat absorbed in the thermoelectric element is radiated from the heat dissipation surface to the outside of the refrigerator through the aluminum heat exchanger outside the refrigerator.

[0004]

In general, the thermoelectric element has a low coefficient of performance (COP), and unless the heat absorption and heat dissipation are performed efficiently, the cooling performance of the thermoelectric element due to the thermoelectric conversion action can be effectively achieved. Not demonstrated. In this sense, the above-described conventional configuration has low heat absorption and heat release efficiency and lacks cooling performance. For this reason, an electronic refrigerator using a thermoelectric element having an extremely small internal volume has only been put to practical use.

The present invention has been made in view of such circumstances, and an object of the present invention is to improve the cooling performance of a thermoelectric element by a thermoelectric conversion effect, and to be able to use the electronic refrigerator with a larger internal volume than before. Is to provide.

[0006]

In order to achieve the above object, an electronic refrigerator according to the present invention comprises: a refrigerator main body constituted by a heat insulating wall; a heat absorbing surface provided on the refrigerator main body; A thermoelectric element serving as a surface, a heat transfer block inside the refrigerator disposed on the heat absorbing surface side of the thermoelectric element so as to be able to transfer heat, and heat transfer to the heat transfer block inside the refrigerator by exchanging heat with air in the refrigerator. A fin-shaped internal heat exchanger formed by extrusion and arranged so as to perform, an external heat transfer block disposed so as to be able to transfer heat to the heat radiation surface side of the thermoelectric element, and an external heat transfer block A thermosiphon for transporting heat absorbed by heat exchange to the heat radiation area by a circulating action of the working fluid, and a refrigerator outside heat exchanger including heat radiation fins provided in the heat radiation area of the thermosiphon ;
Position the heat transfer block outside the chamber below the heat dissipation surface of the thermoelectric element.
The size of the protruding part is larger than the size of the part protruding upward.
It is formed so as to be large (claim 1).

Further , the electronic refrigerator of the present invention has a heat insulating wall.
And the refrigerator body
A thermoelectric element having an inner side as a heat absorbing surface and an outer side as a heat radiating surface,
Inside the chamber arranged to be able to transfer heat to the heat absorbing surface side of this thermoelectric element
The heat absorbed by the heat exchange between the side heat transfer block and
It is arranged to transfer heat to the inner heat transfer block.
Fin shaped internal heat exchanger formed by extrusion molding
And, it was arranged to be able to transfer heat to the heat dissipation surface side of the thermoelectric element
Heat exchange block with the outside heat transfer block and heat exchange with this outside heat transfer block
The absorbed heat is radiated by the circulating action of the working fluid.
Thermosiphon to be transported to
Outside heat exchanger consisting of radiating fins provided in the heat zone
And a working fluid circulation constituting the thermosiphon
Heating area where the pipe contacts the outer heat transfer block
Is mounted so that it is inclined with respect to the vertical line
The a (claim 2).

Further, the electronic refrigerator of the present invention has a heat insulating wall.
And the refrigerator body
A thermoelectric element having an inner side as a heat absorbing surface and an outer side as a heat radiating surface,
Inside the chamber arranged to be able to transfer heat to the heat absorbing surface side of this thermoelectric element
The heat absorbed by the heat exchange between the side heat transfer block and
It is arranged to transfer heat to the inner heat transfer block.
Fin shaped internal heat exchanger formed by extrusion molding
And an external heat exchanger for promoting heat radiation of the thermoelectric element.
The inside heat transfer block is provided with a long side on the inside.
It is formed in a trapezoidal shape, and the long side of the internal heat exchanger is
It is characterized by being arranged so as to be parallel to the fins
To (claim 3).

[0009] In the electronic refrigerator having the above configuration,
When a plurality of thermoelectric elements are provided, the internal heat transfer block may be divided into the number of the thermoelectric elements.

In this case, it is preferable to arrange a plurality of thermoelectric elements in parallel with the flow of the cooling air.

In the case where the working fluid circulating pipe constituting the thermosiphon is press-fitted into a mounting groove formed in the heat transfer block outside the refrigerator and the two are brought into close contact with each other, the working fluid circulating pipe of the working fluid circulating pipe may be used. A coil-shaped reinforcing member for reinforcing the press-fit portion from the inside may be inserted into the portion press-fitted into the mounting groove (Claim 6 ).

Further, it may also be provided with a cooling fan for forcibly cooling the Kurasotogawa heat exchanger (claim 7).

In this case, the cooling fan is disposed below the outside heat exchanger, and the rotation of the cooling fan sucks air downward from the upper side of the refrigerator body along the outside heat exchanger. (Claim 8 ).

Furthermore, a timer means is provided, this by the timer means may be caused to be allowed or stopped reduce the rotational speed of the cooling fan in any time zone set beforehand (claim 9).

Further, the voltage applied to the thermoelectric element may be provided with control means for variably controlling (claim 1
0 ).

In this case, an internal temperature sensor for detecting the internal temperature may be provided, and the control means may variably control the voltage applied to the thermoelectric element according to the detected temperature of the internal temperature sensor ( Claim 11 ).

Furthermore, the control means may be variably controlling the rotational speed of the cooling fan in response to the detected temperature of the interior temperature sensor (claim 12).

Further, a switching power supply may be employed as a power supply for applying a voltage to the thermoelectric element, and the start and stop of the switching operation of the switching power supply may be controlled by an output signal of an internal temperature sensor. 1
3 ).

[0019] In this case, the output signal of the interior temperature sensor may be a switching-off duty ratio of the switching power supply so as to variably control (claim 14).

Further, the thermoelectric element is obtained by adding a predetermined ratio of silicon monoxide to a bismuth / antimony-based material.
Crystal structure may be formed such that the granular structure consisting of crystal grains of about 1 micron (claim 15).

[0021] Also in this case, it may be provided with a cooling fan for forcibly cooling the Kurasotogawa heat exchanger (claim 16).

[0022]

The present inventor has repeated a number of tests on the cooling performance of the electronic refrigerator, and as a result of analyzing the test data,
In particular, it has been found that increasing the heat dissipation capability is effective for improving the cooling performance (because the thermoelectric element itself also generates heat when energized, so that the heat dissipation becomes larger than the heat absorption).

In view of the above, in the first aspect, the outside heat exchanger is constituted by the thermosiphon and the radiating fins provided in the heat radiating area, so that the heat radiating capacity is enhanced and the cooling performance is effectively improved. ing. Meanwhile, the thermosa
In principle, ihon is a heating area
The part above the heated part) is the heat radiation area.
So, to increase the heat radiation area, the heating area (
Block) can be shifted downward, but the heat transfer block
The lower limit is determined by the position of the internal heat exchanger
Therefore, shift the position of the outside heat transfer block downwards
It is not possible. Therefore, the shape of the outside heat transfer block
Is the dimension of the part protruding below the heat dissipation surface of the thermoelectric element.
Is larger than the size of the part protruding upward.
If it is formed, the position of the heat transfer block on the outside
Even if there is a situation that is restricted by the relationship with the
Reducing the height of the heating area of the iPhone
Since it can be enlarged, the heat radiation performance can be further improved.

Also, from the analysis results of the test data described above, since the heat absorption capacity of the internal heat exchanger may be lower than the heat radiation capacity of the external heat exchanger, the internal heat exchanger is extruded. By adopting the fin shape, the manufacturing cost of the internal heat exchanger can be reduced while securing heat absorption capacity (cooling capacity).

In this case, the outer heat transfer block is
The size of the part projecting below the heat radiation surface of the
Be formed so as to be larger than the size of the projected part
Instead of the above, a thermosiphon is configured as in claim 2.
Of the working fluid circulation pipe is inclined with respect to the vertical
If you attach it as described above,
The height of the heating area of the heat sink is relatively low, and the heat dissipation area is expanded.
And heat radiation performance can be improved.

[0026] Further , the heat transfer blower inside the refrigerator may be provided.
When the hook is formed in a trapezoidal shape with the long side inside,
The thermal resistance inside the inner heat transfer block can be reduced,
The heat transfer area on the side heat exchanger side is expanded, and the contact heat resistance
Can be reduced. By the way, the inside heat exchanger is extruded
Forming more fins can reduce manufacturing costs
On the other hand, flatness in the direction perpendicular to the fins can be expected very little
Absent. However, the long side of the internal heat transfer block is
If they are arranged parallel to the heat exchanger fins,
Contact (heat transfer) can be ensured.

In the case where a plurality of thermoelectric elements are provided as in claim 4, if the inside heat transfer block is divided into the number of thermoelectric elements, contact due to the size of the inside heat transfer block increases. The problem of the lowering of the plane accuracy of the surface is solved, the close contact between each thermoelectric element and the internal heat transfer block is ensured, and the contact thermal resistance between them is reduced.

In this case, if a plurality of thermoelectric elements are arranged in parallel to the flow of the cooling air,
The heat radiation of each thermoelectric element is performed uniformly, the heat absorption (cooling) by each thermoelectric element is performed uniformly, and the temperature inside the refrigerator is made uniform.

[0029] According to a sixth aspect of the present invention, a thermosyphon is provided.
When the working fluid circulating pipe constituting the component is press-fitted into the mounting groove formed in the outer heat transfer block and the two are brought into close contact with each other, the working fluid circulating pipe is press-fitted into the mounting groove of the working fluid circulating pipe. If a coil-shaped reinforcing member for reinforcing the press-fit portion from the inside is inserted into the portion where the press-fit portion is inserted, collapse of the working fluid circulating pipe is prevented by the reinforcing member when the working fluid circulating pipe is press-fitted into the mounting groove. Adhesion between the outer heat transfer block and the working fluid circulation pipe is ensured.

Further, as in claim 7, by providing a cooling fan for forcibly cooling the Kurasotogawa heat exchanger, heat dissipation is dramatically improved.

[0031] In this case, as according to claim 8, a cooling fan disposed below the Kurasotogawa heat exchanger, along said by rotation of the cooling fan air from the upper side of the refrigerator body compartment outer heat exchanger downwardly With this configuration, even if the width of the outside heat exchanger is somewhat larger than the width of the cooling fan, the cooling air can be evenly applied to the entire outside heat exchanger.

Further, if the timer means is provided as described in claim 9 and the rotation number of the cooling fan is reduced or stopped in a predetermined time zone by the timer means, for example, The fan noise can be reduced or eliminated at night or the like as required by the location.

Further, as in claim 10, by providing the control means for the voltage applied to the thermoelectric element is variably controlled, thereby varying the cooling capacity needed.

In this case, an internal temperature sensor for detecting the internal temperature is provided, and the voltage applied to the thermoelectric element is variably controlled according to the temperature detected by the internal temperature sensor. If this is the case, an optimal cooling operation according to the temperature in the refrigerator can be performed.

Furthermore, as claimed in claim 12, if the rotational speed of the cooling fan in response to the detected temperature of the interior temperature sensor so as to variably control, fan noise is also relatively reduced.

According to a thirteenth aspect , a switching power supply is employed as a power supply for applying a voltage to the thermoelectric element.
If the start / stop of the switching operation of the switching power supply is controlled by the output signal of the internal temperature sensor, the power conversion efficiency is higher than that of the series type power supply, power saving is possible, and the thermoelectric element is There is no need to turn on / off the applied voltage at the relay, so there is no problem of noise when switching contacts and deterioration of contacts that occur when using a relay, and there is no problem of self-generated noise due to turning on / off a large current. .

[0037] In this case, as in claim 14, the application of the output signal of the inside temperature sensor switching-off duty ratio of the switching power supply if to variably control, the thermoelectric element by feeding back the internal temperature The control circuit for variably controlling the voltage is also simplified.

Further, as claimed in claim 15, thermoelectric element,
By adding silicon monoxide to a bismuth-antimony-based material at a predetermined ratio to form a crystal structure having a granular structure of crystal grains of about 1 micron, the figure of merit indicating the thermoelectric conversion performance increases, The performance of the thermoelectric element itself is also improved.

[0039] In this case, as in claim 16, by providing a cooling fan for forcibly cooling the Kurasotogawa heat exchanger, cooling performance is further improved.

[0040]

1 to 10 show a first embodiment of the present invention.
It will be described based on. The refrigerator main body 31 is constituted by a heat insulating wall 35 filled with a heat insulating material 34 between an outer box 32 and an inner box 33, and a refrigerator space 36 is defined as a refrigerator space surrounded by the heat insulating wall 35. A front opening of the refrigerator compartment 36 is a door 37.
Is opened and closed by

On the other hand, the heat insulating wall 35 on the back of the refrigerator body 31
As shown in FIG. 2, for example, two thermoelectric elements 39 are disposed on the left and right in the through hole 38 formed in the
The heat-absorbing surface 9 faces the inside of the refrigerator and the heat-radiating surface faces the outside of the refrigerator.

In this case, each thermoelectric element 39 is made of bismuth
By adding silicon monoxide (SiO) at a predetermined ratio (for example, about 2 atom% or less) to an antimony-based (Bi-Sb-based) semiconductor material, the crystal structure becomes a granular structure including crystal grains of about 1 micron. Is formed. If a cluster ion beam evaporation method (ICB method) is adopted as this manufacturing method, a high-quality crystal can be easily manufactured. For details of this manufacturing method,
It is described in the specification of Japanese Patent Application No. 3-78556 previously filed by the present applicant.

Generally, the performance index Z indicating the thermoelectric conversion performance of the thermoelectric element 39 is obtained by the following equation (1).

Z = S ² · σ / K (1) (S: thermoelectric power, σ: electric conductivity, K: heat conductivity) In this case, thermoelectric power S is a value inherent to the substance, and Since the rate σ is hardly affected by crystallinity, the figure of merit Z
It is effective to decrease the thermal conductivity K, which is the denominator of the equation (1), in order to increase. Therefore, as described above, if the crystal structure is a granular structure including crystal grains of about 1 micron, the thermal conductivity due to phonons decreases, the thermal conductivity K decreases, and the figure of merit Z increases.

The thermoelectric element 39 having such thermoelectric conversion characteristics is
It is sandwiched between the inside heat transfer block 40 and the outside heat transfer block 41. These internal heat transfer blocks 4
The heat transfer block 41 and the outer heat transfer block 41 are both formed of a material having high thermal conductivity, for example, an aluminum alloy or a copper alloy. In this case, one outer heat transfer block 41 is 2
The heat transfer block 40 is divided into the number of thermoelectric elements 39 (two thermoelectric elements 39 in the first embodiment). This solves the problem of the decrease in the planar accuracy of the contact surface due to the increase in the size of the internal heat transfer block 40, and the internal heat transfer block 40 and the thermoelectric element 3
The contact property (thermal conductivity) with No. 9 is improved, and the contact thermal resistance between the two is reduced.

The thermoelectric element 39 and both heat transfer blocks 4
As shown in FIG. 4, 0 and 41 are attached by stepped screws 42. Hereinafter, this attachment structure will be described.
That is, the mounting protrusion 43 is integrally formed in the through hole 38 of the heat insulating wall 35, and the screw insertion hole 44 is formed in the mounting protrusion 43. Correspondingly, each heat transfer block 4
The screw holes 40a and the insertion holes 4
1a is formed. A stepped sleeve 45 made of an insulating material and a spring 46 housed therein are attached to the shaft of the stepped screw 42.
In the state where the small diameter portion of No. 5 is fitted in the insertion hole 41a, the screw portion at the tip of the stepped screw 42 is tightened into the screw hole 40a. In this mounting state, the thermoelectric element 39 is held between the heat transfer blocks 40 and 41 by the elastic force of the spring 46.

In this mounting structure, since the pressing force between the thermoelectric element 39 and the heat transfer blocks 40 and 41 is set by the elastic force of the spring 46, the tightening torque of the stepped screw 42 need not be managed. And a stable pressing force can be obtained. Therefore, there is an advantage that the assembling work at the time of manufacturing is simple and there is no possibility of the thermoelectric element 39 being deformed or damaged.

On the other hand, as shown in FIGS. 1 and 2, a heat exchanger 47 inside the refrigerator is attached to the heat transfer block 40 inside the refrigerator by screwing or the like. (Not shown). The inside heat exchanger 47 is made of a material having good heat conductivity (for example, corrosion-resistant aluminum alloy,
By extruding pure aluminum or the like, a number of fins 47a are formed in a fin shape arranged in parallel,
The surface is anodized to reduce the thermal resistance. The internal heat exchanger 47 is mounted with the fins 47a facing up and down so as not to hinder the natural convection of cold air, and the interval between the fins 47a is, for example, about 10 mm to 15 mm. The front surface of the internal heat exchanger 47 is covered with a cover plate 48 made of a material having good heat conductivity such as aluminum.

In this case, the internal heat transfer block 40 is formed in a trapezoidal shape having a long side on the internal side. Thereby, while reducing the thermal resistance in the internal heat transfer block 40, the heat transfer area between the internal heat exchanger 47 and the internal heat exchanger 47 is increased,
The contact thermal resistance is also reduced. The present inventor has determined by experiment the relationship between the expansion ratio β (β = long side / short side) of the internal heat transfer block 40 and the thermal resistance, and the experimental results are shown in FIG. FIG. 7 shows the ratio of the change in the thermal resistance when the enlargement ratio β is changed, assuming that the thermal resistance when the enlargement ratio β = 1 is “1.0”. The “total heat resistance” is data obtained by adding the thermal resistance in the internal heat transfer block 40 and the contact thermal resistances on both sides, and “only the internal heat transfer block” indicated by a dotted line indicates the internal heat transfer block 40. The data is for only the thermal resistance inside.

As is apparent from FIG. 7, a remarkable effect of reducing the thermal resistance is observed up to an enlargement ratio β of about 3, but it becomes almost saturated when the enlargement ratio β exceeds 4. Therefore, it is preferable to set the enlargement ratio β within a range of, for example, about 2.5 to 4.0.

By the way, the fin-shaped internal heat exchanger 47 formed by extrusion molding has a fin 47
Flatness in the direction orthogonal to a cannot be expected much (however, linearity in the direction parallel to the fin 47a is ensured). In consideration of this, the trapezoidal internal heat transfer block 40 has a long side whose fin 47 a
It is arranged in the up-down direction so as to be parallel. Thereby, the contact property (heat transfer property) between the internal heat transfer block 40 and the fin-shaped internal heat exchanger 47 is ensured, and the contact thermal resistance between them is reduced.

On the other hand, as shown in FIGS. 1 and 2, an outside heat exchanger 49 is provided on the outside heat transfer block 41 side. This outside heat exchanger 49 is a thermosiphon 5
0 and a number of radiating fins 51 provided in the heat radiating area of the thermosiphon 50.
As shown in FIG. 3, they extend vertically and are arranged in parallel in a horizontal line.

The thermosiphon 50 is configured such that a working fluid (for example, a refrigerant) is sealed in a closed loop working fluid circulation pipe 52, and the circulation action of the working fluid causes the heat transfer block 41 to move from the outside heat transfer block 41. The heat is absorbed, and the heat is transported to the heat radiation area (radiation fin 51) side to radiate the heat. In this embodiment, two thermosiphons 50 are provided corresponding to the number (two) of thermoelectric elements 39, and two independent working fluid circulation pipes 52 are integrated by radiation fins 51.

The heat transfer structure between the working fluid circulation pipe 52 of the thermosiphon 50 and the outside heat transfer block 41 will be described below with reference to FIGS. That is, two mounting grooves 54 extending in the vertical direction are formed in the outer heat transfer block 49 by the two pairs of ribs 53, and the working fluid circulation pipes 52 are fixed in the respective mounting grooves 54 by press fitting. . A coil-shaped reinforcing member 55 made of metal wire for reinforcing the press-fit portion from the inside is inserted into a portion of the working fluid circulation pipe 52 which is press-fitted into the mounting groove 54.

This prevents the working fluid circulating pipe 52 from being crushed when the working fluid circulating pipe 52 is pressed into the mounting groove 54 by the reinforcing member 55, so that the outer heat transfer block 49 and the working fluid circulating pipe 52 are in close contact with each other. Nature is secured. In addition, the contact between the coil-shaped reinforcing member 55 and the inner peripheral surface of the working fluid circulation pipe 52 is also improved by the pressure input,
Heat transfer between the two is improved. In addition, the coil-shaped reinforcing member 55 not only increases the heat transfer area, but also promotes nucleate boiling, improves the boiling heat transfer, and reduces the thermal resistance of this portion in combination with the above-described circumstances. I do.

In the thermosiphon 50, a portion above the heating region (the portion heated by the outside heat transfer block 41) is a heat dissipation region. The heat transfer block 41) may be shifted downward, but since the lower limit of the position of the outer heat transfer block 41 is determined by the position of the inner heat exchanger 47, the position of the outer heat transfer block 41 is shifted downward indiscriminately. It is not possible.

Therefore, in this embodiment, as shown in FIG. 5A, the outer heat transfer block 41 is formed such that the size of the portion projecting below the heat radiation surface of the thermoelectric element 39 is smaller than that of the portion projecting upward. It is formed so as to be larger than the size. Thereby, even if there is a situation in which the position of the outer heat transfer block 41 is restricted by the relationship with the inner heat exchanger 47,
The height of the heating area of the thermosiphon 50 can be made relatively low so that the heat radiation area can be expanded, and the heat radiation performance of the thermosiphon 50 can be improved.

Further, in this embodiment, even if the refrigerator main body 31 is installed in a slightly inclined state, the working fluid circulation pipe 52 is provided as shown in FIG. 3 so as not to obstruct the flow of the working fluid. The portion on the heat radiation fin 51 side is inclined with respect to the horizontal plane.

On the other hand, as shown in FIG. 1, the outside heat exchanger 49 is covered by a back cover 56 attached to the back of the refrigerator body 31, and an intake hole 57 is formed in the upper surface of the back cover 56. Have been. This back cover 56
The cooling fan 5 is located below the outside heat exchanger 49 in the inside.
8 are arranged. The cooling fan 58 is, for example, a propeller fan, and is rotated by a fan motor 59.

When the cooling fan 58 rotates, the outside air is sucked from the intake hole 57 on the upper surface of the rear cover 56 and flows downward along the gap between the radiation fins 51 of the outside heat exchanger 49. Exhaust hole 60 on the lower surface of back cover 56
Discharged from With such cooling air flow, even if the width of the outside heat exchanger 49 is somewhat larger than the width of the cooling fan 58, the cooling air can be evenly applied to the entire outside heat exchanger 49. Can be.

In this case, since the two thermoelectric elements 39 are arranged in parallel to the flow of the cooling air, the heat of each thermoelectric element 39 is evenly distributed, and the heat absorption (cooling) by each thermoelectric element 39 is performed. Is performed evenly, and the temperature in the refrigerator is made uniform.

Next, the configuration of the electric circuit will be described with reference to FIGS. For example, 100V commercial AC power supply 69
Is supplied to the rectifier circuit 71 through the input filter 70, is rectified by the smoothing capacitor 72, and is supplied to the switching power supply 73. The switching power supply 73 converts the supplied DC power into power MOSF
By switching at high speed by a switching element 74 such as an ET, a high-frequency voltage is generated in the secondary winding of the transformer 75. This high-frequency voltage is rectified by a rectifier circuit 78 including two diodes 76 and 77, and a DC voltage obtained by smoothing with a choke coil 79 and a smoothing capacitor 80 is applied to the thermoelectric element 39.

On the other hand, auxiliary power supply circuits 81 and 82 for driving switching element 74 rectify and smooth AC power supplied from a commercial AC power supply via step-down transformer 83, and convert it to DC power. One auxiliary power supply circuit 81 includes a photodiode 85 constituting a photocoupler 84.
Is connected to the base of an NPN transistor 86. The collector of the transistor 86 has a PN
The base of a P-type transistor 87 is connected to the switching element 74 on the collector side of the transistor 87.
(Power MOSFET) is connected.

The collector of a transistor 90 of a control circuit 89 as a control means is connected to the other auxiliary power supply circuit 82 via a light emitting diode 88 constituting a photocoupler 84. The control circuit 89 controls the transistors 86 and 87 and the switching by controlling on / off of the transistor 90 (disconnection of the light emitting diode 88) in accordance with the inside temperature detected by the inside temperature sensor 91 as described later. The on / off duty ratio of the element 74 is variably controlled to variably control the voltage applied to the thermoelectric element 39.

The above-mentioned internal temperature sensor 91 is composed of, for example, a thermistor having a negative temperature characteristic. A series circuit of the inside temperature sensor 91 and the resistor 92 is connected between the DC power supply voltage Vc and the ground terminal, and a voltage V generated at a connection point 93 between the inside temperature sensor 91 and the resistor 92 is formed.
s is input to the inverting input terminal (−) of the operational amplifier 95 via the resistor 94. The reference voltage Vo divided by the two resistors 96 and 97 is input to the non-inverting input terminal (+) of the operational amplifier 95 via the resistor 98. A negative feedback resistor 99 is connected between the output terminal of the operational amplifier 95 and the inverting input terminal (-).

The output terminal of the operational amplifier 95 is connected to a resistor 1
00 and the subsequent stage of the duty ratio determination circuit 101
It is connected to the input side of the T circuit 102. As shown in FIG. 10, the duty ratio determination circuit 101 varies the on / off duty ratio of the oscillation waveform output from the oscillation circuit 103 by the output signal of the operational amplifier 95 corresponding to the internal temperature. The oscillation circuit 103 has two NO
This is a multivibrator circuit composed of T circuits 104 and 105, two resistors 106 and 107, and a capacitor 108. The multivibrator circuit performs an oscillating operation using charging and discharging of the capacitor 108. The oscillation cycle of the oscillation circuit 103 is 2.2RC (R: resistance value of the resistor 107,
C: capacitance of the capacitor 108).

On the other hand, the duty ratio determining circuit 101
OT circuit 109, capacitor 110, resistor 111 and N
The OT circuit 102 is configured to be connected in series. As described above, the output voltage of the operational amplifier 95 is also applied to the input side of the subsequent NOT circuit 102. This NOT
The output terminal of the circuit 102 is connected to the base of the transistor 90 via the resistor 112.

The voltage applied to the thermoelectric element 39 is fed back to the input side of the NOT circuit 102 via the resistor 113. However, this feedback is used only for correcting input changes and load fluctuations. The main control is based on the output voltage (inside temperature) of the operational amplifier 95, and the feedback is for fine adjustment. Therefore, the resistance value of the resistor 113 is set to be large so that the feedback ratio becomes small.

The operation of the control circuit 89 configured as described above will be described below. As shown in FIG. 9, when the temperature inside the refrigerator decreases due to the cooling operation, the resistance of the temperature sensor 91 inside the refrigerator increases accordingly, and the inverted input of the operational amplifier 95 from the connection point 93 of the temperature sensor 91 inside the refrigerator. The voltage Vs input to the terminal (−) gradually decreases, and the difference (Vo−Vs) from the input voltage Vo of the non-inverting input terminal (+) gradually increases. Therefore, as the internal temperature decreases, the output voltage of the operational amplifier 95 gradually increases, and the input voltage of the NOT circuit 102 of the duty ratio determination circuit 101 also increases due to the increase of the output voltage.

On the other hand, as shown in FIG.
3 oscillates at a constant cycle, and the oscillation pulse is input to the duty ratio determination circuit 101. This oscillation pulse is NO
By passing through the T circuit 109, the capacitor 110, and the resistor 111, the input voltage of the NOT circuit 102 becomes
As shown in (1), rising or falling is repeated in synchronization with the oscillation pulse. When the input voltage of the NOT circuit 102 exceeds the threshold voltage Vth, the NOT circuit 10
2 is inverted to a low level, and if the input voltage thereof is lower than the threshold voltage Vth, the NOT circuit 102
Is inverted to a high level.

In this case, while the output of the NOT circuit 102 is at the high level, the transistor 90 is turned on and the light emitting diode 88 of the photocoupler 84 is energized. As a result, the photodiode 85 is turned on, the transistors 86 and 87 and the switching element 74 are turned on, and a voltage is applied to the thermoelectric element 39 by the switching power supply 73.

On the other hand, while the output of the NOT circuit 102 is at the low level, the transistor 90 is turned off, the power supply to the light emitting diode 88 of the photocoupler 84 is cut off, and the transistors 86 and 87 and the switching element 74 are turned off.

As described above, if the internal temperature decreases,
The output voltage of the operational amplifier 95 rises and the NOT circuit 102
As shown in FIG. 10, the input voltage of
The time during which the input voltage of the T circuit 102 exceeds the threshold voltage Vth becomes shorter, and the pulse width of the high-level signal output from the NOT circuit 102 becomes shorter. For this reason, as the internal temperature decreases, the transistors 90, 86,
The on-periods of the switching element 87 and the switching element 74 are shortened, the switching on / off duty ratio of the switching power supply 73 is reduced, and the voltage applied to the thermoelectric element 39 is reduced. As a result, as the internal temperature decreases,
The cooling operation is automatically weakened, and the optimum cooling operation according to the temperature in the refrigerator is performed.

When the internal temperature falls below the set temperature, the output voltage of the operational amplifier 95 exceeds the threshold voltage Vth of the NOT circuit 102, and the input voltage of the NOT circuit 102 always exceeds the threshold voltage Vth. , NOT circuit 102 is maintained at a low level. Therefore, when the internal temperature is lower than the set temperature, the transistors 90, 86, 87 and the switching element 74 are maintained in the off state, the switching operation of the switching power supply 73 is stopped, and the voltage applied to the thermoelectric element 39 is reduced. It becomes "0 V" and the cooling operation is stopped.

On the other hand, during the cooling operation, the cooling fan 58 is rotated by the fan motor 59. This cooling fan 58
At the time of rotation of the outside, the outside air is sucked from the intake hole 57 on the upper surface of the rear cover 56 and flows downward along the gap between the radiation fins 51 of the outside heat exchanger 49, and the lower surface of the rear cover 56 It is discharged from the exhaust hole 60. With such cooling air flow, even if the width of the outside heat exchanger 49 is somewhat larger than the width of the cooling fan 58, the cooling air can be evenly applied to the entire outside heat exchanger 49. Thus, heat can be efficiently dissipated.

Further, since the two thermoelectric elements 39 are arranged in parallel to the flow of the cooling air, each thermoelectric element 3
9 is evenly dissipated, heat absorption (cooling) by each thermoelectric element 39 is evenly performed, and the temperature in the refrigerator is made uniform.

In this embodiment, the operation of the cooling fan 58 is also controlled by the output signal of the internal temperature sensor 91 (the output signal of the duty ratio determining circuit 101). That is, the drive control circuit (not shown) of the fan motor 59 turns on when the output of the duty ratio determination circuit 101 is at a high level and turns off when the output is at a low level, thereby reducing the voltage applied to the fan motor 59. PWM control is performed. This allows
As the temperature in the refrigerator decreases, the voltage applied to the fan motor 59 automatically decreases, the rotation speed of the cooling fan 58 decreases, and the fan noise decreases. In this case, as described above, as the internal temperature decreases, the voltage applied to the thermoelectric element 39 also decreases, and the amount of heat dissipation decreases. Therefore, even if the rotation speed of the cooling fan 58 is reduced, insufficient heat dissipation occurs. There is no.

When the internal temperature falls below the set temperature, the voltage applied to the thermoelectric element 39 becomes “0 V” and the voltage applied to the fan motor 59 also becomes “0 V”. Is stopped.

By the way, the present inventor repeated many tests on the cooling performance of the electronic refrigerator, and as a result of analyzing the test data, it was found that, in particular, it was effective to improve the cooling performance to enhance the cooling performance. (Because the thermoelectric element 39 itself also generates heat when energized, the amount of heat radiation is greater than the amount of heat absorbed.)

Therefore, in this embodiment, the outside heat exchanger 49 is composed of the thermosiphon 50 and the radiating fins 51, so that the heat radiating capacity is increased and the cooling performance is effectively improved. On the other hand, from the analysis results of the test data,
The heat absorption capacity of the internal heat exchanger 47 is the same as the external heat exchanger 49.
Since the heat radiation capacity may be lower than that of the internal heat exchanger 47, the internal heat exchanger 47 may be formed into a fin shape by extrusion, so that the internal heat exchanger 47 may have a sufficient heat absorbing capacity (cooling capacity). 47 is reduced in manufacturing cost.

In the first embodiment described above, the thermoelectric element 3
9 and the number of rotations of the cooling fan 58 are variably controlled in accordance with the temperature in the refrigerator. However, as in the second embodiment of the present invention shown in FIGS. 3
The variable control of the applied voltage to 9 and the rotation speed of the cooling fan 58 may not be performed, and only the on / off may be controlled in accordance with the internal temperature.

In the second embodiment, the operational amplifier 95 of the first embodiment is replaced with a comparator 120, and the output terminal of the comparator 120 and the non-inverting input terminal (+)
And a feedback resistor 121 is connected between the second embodiment and the other configuration is the same as that of the first embodiment.

In this case, when the internal temperature is higher than the set temperature, the voltage V input from the connection point 93 of the internal temperature sensor 91 to the inverting input terminal (−) of the comparator 120 is output.
s becomes higher than the input voltage Vo of the non-inverting input terminal (+), and the output of the comparator 120 is maintained at a low level. For this reason, the input voltage of the NOT circuit 102 is not affected by the output of the comparator 120, and repeatedly rises or falls with a constant waveform in synchronization with the oscillation pulse output from the oscillation circuit 103 as shown in FIG. Become. Thus, when the internal temperature is higher than the set temperature, N
The width of the output pulse of the OT circuit 102 becomes constant, the on / off duty ratio of the transistors 90, 86, 87 is kept constant, the switching on / off duty ratio of the switching power supply 73 becomes constant, and the voltage applied to the thermoelectric element 39 also increases. Be kept constant. At this time, the cooling fan 58 is also operated at a constant rotation speed.

On the other hand, when the internal temperature falls below the set temperature, the voltage V input from the connection point 93 of the internal temperature sensor 91 to the inverting input terminal (-) of the comparator 120 is output.
s falls below the input voltage Vo of the non-inverting input terminal (+), and the output of the comparator 120 is inverted to a high level. Accordingly, the input voltage of the NOT circuit 102 rises by the output voltage of the comparator 120, the input voltage of the NOT circuit 102 always exceeds the threshold voltage Vth, and the output of the NOT circuit 102 is maintained at a low level. Is done. Therefore, when the internal temperature is equal to or lower than the set temperature, the transistors 90, 86, 87 and the switching element 74 are maintained in the off state, and the switching power supply 73
Is stopped, the voltage applied to the thermoelectric element 39 becomes "0 V", and the cooling operation is stopped. At this time, the operation of the cooling fan 58 is also stopped.

In the first and second embodiments described above, the duty ratio determination circuit 101 is
9, capacitor 110, resistor 111 and NOT circuit 10
2 are connected in series. However, as in the third embodiment of the present invention shown in FIG.
A NAND circuit 123 to which an oscillation pulse of the oscillation circuit 103 is input is added to an input side of the NAND circuit 123, and an output of the NOT circuit 102 is output via the NOT circuit 124 to the NAND circuit 123.
May be fed back. With this configuration, the output waveform of the duty ratio determination circuit 122 receives feedback, and thus has the advantage of more stable control.

In each of the first and second embodiments described above, the switching power supply 73 is used as a power supply for applying a voltage to the thermoelectric element 39. Therefore, the power conversion efficiency is higher than that of the series power supply, and There is an advantage that power can be used. In addition, since there is no need to turn on and off the voltage applied to the thermoelectric element 39 by a relay, there is no problem of noise or deterioration of the contact at the time of contact switching that occurs when a relay is used. There is also an advantage that there is no problem of generated noise.

However, it is needless to say that the present invention is not limited to the switching power supply, but may employ a series type power supply.

As an embodiment employing this series type power supply, there is a fourth embodiment of the present invention shown in FIGS.

In the fourth embodiment, a 100 V commercial AC power supply 125 is stepped down by a power transformer 126. This power transformer 126 has two secondary windings 126a and 12a.
6b, and the AC voltage induced in one secondary winding 126a is rectified by the rectifier circuit 127 and the smoothing capacitor 128 to become a DC voltage of, for example, 20V. The AC voltage induced in the other secondary winding 126b is rectified by the rectifier circuit 129 and the smoothing capacitor 130 to become a DC voltage of, for example, 8V, which is divided by the two resistors 131, 132 to divide the DC voltage of, for example, 5V. Get the voltage. And this 5V or 2
0 V DC voltage is applied to the relay switch 13 according to the internal temperature.
The switching operation of No. 3 selectively applies to the thermoelectric element 39. This relay switch 133 is connected to the coil 1
When the power is cut off at 35, the state is switched to the contact B (20V) side.

On the other hand, the processing circuit for the output signal of the in-compartment temperature sensor 91 is almost the same as that of the second embodiment described above, and the transistor 134 is driven by the output signal of the comparator 120. On the collector side of the transistor 134,
A coil 135 for driving the relay switch 133 is connected.

The collector of the transistor 134 is connected to the base of a transistor 136 for turning the fan motor 59 on and off. A coil 138 of a relay switch 137 for turning on and off the fan motor 59 is connected to the collector side of the transistor 136.

The feature of the fourth embodiment is that even when the internal temperature reaches the lower limit of the set temperature, the voltage applied to the thermoelectric element 39 is maintained at, for example, a voltage of "5 V" without being set to "0 V". (This advantage will be described later). However, thermoelectric element 3
When the voltage applied to 9 is set to "5 V", the amount of heat radiation is small, so that the fan motor 59 is turned off.

Hereinafter, the operation of the electric circuit of FIG. 14 will be described specifically. When the internal temperature decreases to the lower limit of the set temperature, the voltage Vs input from the connection point 93 of the internal temperature sensor 91 to the non-inverting input terminal (+) of the comparator 120
Rises above the input voltage Vo of the inverting input terminal (-), and the output of the comparator 120 is inverted to a high level. Along with this, the transistor 134 is turned on to energize the coil 135 of the relay switch 133, and the contact is switched to the A (5V) side. As a result, the voltage applied to the thermoelectric element 39 becomes “5 V”, and the cooling operation is continued with small power.

At this time, when the transistor 134 is turned on, the transistor 136 is turned off, the relay switch 137 returns to the off state, the fan motor 59 is stopped, fan noise is eliminated, and the thermoelectric element 39 is supercooled. To prevent

Thereafter, when the internal temperature rises to the upper limit of the set temperature, the output of the comparator 120 is inverted to a low level, and the transistor 134 is turned off. As a result, the relay switch 133 is switched to the contact B (20 V) side, the voltage applied to the thermoelectric element 39 becomes “20 V”, and the normal cooling operation is continued.

At this time, when the transistor 134 is turned off, the transistor 136 is turned on, the relay switch 137 is turned on, the fan motor 59 is operated, and the outside heat exchanger 49 is forcibly cooled.

By the way, when the power supply to the thermoelectric element 39 is completely turned off, when the thermoelectric element 39 cools below the outside temperature, dew condensation may occur on the surface of the thermoelectric element 39 or the thermoelectric element 3
9 may absorb moisture. In such a state, when the cutoff of the thermoelectric element 39 is repeated, the thermoelectric element 3
No. 9 has reduced durability.

In this regard, as in the fourth embodiment, the thermoelectric element 3
9 is continuously energized with a variable voltage.
9 can be prevented beforehand, and the durability of the thermoelectric element 39 can be improved.

Further, according to the results of experiments conducted by the present inventor, it has been found that the continuous power supply of the variable voltage to the thermoelectric element 39 saves power compared to the intermittent power supply. The experimental results are shown in Tables 1 and 2. Tables 1 and 2 show that the refrigerator 31 has an inner volume of 30 liters,
5 shows experimental data obtained by using an electronic refrigerator having a wall thickness of 50 mm. Table 1 shows data of the voltage variable continuous operation (fourth embodiment), and Table 2 shows data of the intermittent operation.

[0100]

[Table 1]

[Table 2]

Comparing these Tables 1 and 2, the power saving effect of the variable voltage continuous operation of the fourth embodiment can be clearly understood.

In each of the first to fourth embodiments described above, the cooling operation is automatically controlled in accordance with the inside temperature regardless of day or night. However, the present invention shown in FIG. 16 and FIG. As in the fifth embodiment, a timer means 141 which allows the user to arbitrarily set the time is provided, and the voltage applied to the thermoelectric element 39 is reduced in an arbitrary time zone preset by the timer means 141. Alternatively, the configuration may be such that the rotation speed of the fan motor 59 is reduced.

In this case, the user operates the timer means 141 to operate the night time zone (for example, from 6:00 pm to 9 am
17), during the daytime (from 9:00 am to 6:00 pm), the thermoelectric element control circuit 142 applies the voltage to the thermoelectric element 39 in accordance with the temperature detected by the internal temperature sensor 91 as shown in FIG. The voltage is varied in two steps, high and low. At this time, the fan motor control circuit 143 controls the fan motor 5
9 is operated in a rated manner to promote the heat radiation of the thermoelectric element 39.

On the other hand, in the nighttime period set by the timer means 141, the voltage applied to the thermoelectric element 39 is reduced by the thermoelectric element control circuit 142, and the rotation speed of the fan motor 59 is reduced by the fan motor control circuit 143. To reduce fan noise. For this reason, the user does not care about the fan noise at bedtime at night.

In the fifth embodiment, the timer means 14
In the time period set by 1, the operation level is lowered to continue the cooling operation, but it goes without saying that the cooling operation may be stopped.

In place of the timer means 141, FIG.
As shown in the sixth embodiment of the present invention, a brightness detecting means 144 for detecting the brightness of the room is provided, and when the room is dark, the brightness detecting means 144 The 144 output signal may be prioritized.
That is, when the room is dark, the cooling operation is lowered or stopped regardless of the temperature inside the refrigerator.

In a hotel or the like, if the curtain is closed, the room is dark even in the daytime. Even in this case, the occupancy information obtained from the occupancy management computer or the door lock at the front is used as control data. In this case, it is possible to appropriately control the cooling operation according to the use state of the room.

On the other hand, in the first embodiment described above, the cooling air is sucked from the upper surface side of the refrigerator
9 and FIG.
As shown in the seventh embodiment of the present invention, the cooling air is sucked in from the air inlet 145 on the bottom side of the refrigerator main body 31 and flows upward along the heat exchanger 49 outside the refrigerator. The air may be discharged from the exhaust hole 146 (FIG. 19).
The flow of the cooling air is indicated by white arrows in FIG.

In the seventh embodiment, a horizontally long cross flow fan is employed as the cooling fan 147, so that the cooling air discharged from the cooling fan 147 can evenly hit the entire heat exchanger 49 outside the refrigerator. ing. Further, in order to improve the efficiency of air intake from the front side of the outer bottom of the refrigerator main body 31, a heat insulating wall 148 at the lower rear portion of the refrigerator main body 31 is formed in a slanted shape to increase the opening area on the intake side and reduce the ventilation resistance. Has been reduced. As described above, the method of inhaling air from the front side of the bottom has an advantage that the influence of the room wall on the rear side is not required and the restriction on the installation location is reduced as compared with the method of inhaling air from the rear side. In order to reduce fan noise, a sound absorbing material 149 is attached to an inner wall around the cooling fan 147.

On the other hand, in the eighth embodiment of the present invention shown in FIG. 21, in order to enlarge the heat transfer area between the internal heat transfer block 40 and the internal heat exchanger 47, the internal heat transfer block 40 and the internal heat transfer block The joint surface of the inner heat exchanger 47 is uneven (for example, saw-tooth shape)
And in a state where both are engaged with each other, they are fastened and fixed by screws 151. In this case, a heat-conducting putty (not shown) is applied to a joint between the internal heat transfer block 40 and the internal heat exchanger 47.

In the first embodiment described above, the shape of the heat transfer block 41 outside the refrigerator is such that the size of the portion projecting below the heat radiation surface of the thermoelectric element 39 is larger than the size of the portion projecting upward. By doing so, the height of the heating area of the thermosiphon 50 is relatively reduced to enlarge the heat radiation area, and the heat radiation performance is improved. It can also be obtained by the ninth embodiment of the invention.

In the ninth embodiment, the thermosiphon 50
(A portion heated by the outer heat transfer block 41) is inclined with respect to the vertical line integrally with the outer heat transfer block 41. Thus, by inclining the heating area of the thermosiphon 50,
The height of the heating area becomes relatively low, and the heat radiation area can be enlarged correspondingly to improve the heat radiation performance.

The outer heat transfer block 41 does not necessarily need to be tilted. If the height of the outer heat transfer block 41 is reduced to increase the width, the thermosiphon can be moved without tilting the outer heat transfer block 41. Only the 50 heating regions need to be tilted.

FIGS. 23 and 24 show the tenth embodiment of the present invention.
It shows an example. In the tenth embodiment, a liquid reservoir 153 for storing a radiated working fluid that is radiated and liquefied below the thermosiphon 50, and a working fluid supplied from the liquid reservoir 153 is heated to provide a heat transfer block outside the refrigerator. 41
The heater 154 (see FIG. 24) for feeding to the side is provided at substantially the same height position.

In this case, bubbles are generated in the working fluid by the heating of the heater 154, and the circulation of the working fluid is promoted by the rising force (bubble pump action) of the bubbles. Also,
In the principle of the thermosiphon 50, the liquid level on the condensation side is almost equal to the height of the heating area (boiling evaporating area). Therefore, when the heater 154 is provided as in the tenth embodiment, it is almost the same as the heater 154. The liquid level will be located in the liquid reservoir 153 at the height. For this reason, the area above the liquid reservoir 153 acts as a condensation area (heat radiation area), and the heat radiation area can be greatly increased.

Further, by making the capacity of the liquid reservoir 153 to a certain size, fluctuations in the liquid level can be suppressed.
53, it is possible to eliminate the adverse effect of the fluctuation of the liquid level on the circulating action of the working fluid, and to secure a stable circulating flow rate.

On the other hand, in the above-described first embodiment, in order to secure the close contact between the working fluid circulation pipe 52 of the thermosiphon 50 and the heat transfer block 41 outside the refrigerator, a coil-shaped reinforcement is provided in the working fluid circulation pipe 52. With the member 55 inserted, the working fluid circulation pipe 52 is connected to the outside heat transfer block 41.
Is fixed to the mounting groove 54 by press-fitting. However, an eleventh embodiment of the present invention shown in FIG. 25 may be used.

In the eleventh embodiment, a through hole 156 penetrating vertically is formed in the outer heat transfer block 41, and a copper pipe 157 of a predetermined length is inserted through the through hole 156. The diameter of the copper pipe 157 is enlarged by the hydraulic pressure as described later, and the copper pipe 157 is tightly fixed to the inner peripheral surface of the through hole 156. An aluminum pipe 158 is argon-welded to both ends of the copper pipe 157 to form a closed-loop working fluid circulation pipe 52. The copper pipe 157 has a filling port 159 for filling a working fluid.

Next, the manufacturing procedure will be described. First, a copper pipe 157 is inserted into the through hole 156 of the heat transfer block 41 outside the refrigerator. Thereafter, using a hydraulic press (not shown), the copper pipe 157 is closed with one end of the copper pipe 157 closed.
A liquid such as oil is injected into the inside, and a liquid pressure is applied to the copper pipe 157, and the diameter of the copper pipe 157 is enlarged by the liquid pressure. Thereby, the copper pipe 157 is tightly fixed to the inner peripheral surface of the through hole 156.

Thereafter, an aluminum pipe 158 is argon-welded to both ends of the copper pipe 157 to form a closed-loop working fluid circulation pipe 52. Then, a copper charge pipe 160 is attached to a filling port 159 of the copper pipe 157 by a copper brazing, and a vacuum and a working fluid are filled through the charge pipe 160. After the completion of the filling, the filling port 159 is closed.

The reason why the copper pipe 157 is used is that argon welding with the aluminum pipe 158 is easy (welding of aluminum is difficult). In addition, there is an advantage that the copper charge pipe 160 can be easily brazed to the filling port 159 of the copper pipe 157.

FIG. 26 shows a twelfth embodiment of the present invention. In the twelfth embodiment, the outer heat transfer block 163 is formed in a hollow shape, and two working fluid circulation pipes 164 are both open to the hollow portion in the outer heat transfer block 163. With this configuration, there is an advantage that the operation of filling the two working fluid circulation pipes 164 with the working fluid only needs to be performed once, and the productivity is improved.

Note that the present invention is not limited to the above embodiments,
The number of the thermoelectric elements 39 is not limited to two, and may be one or three or more. Also, in a small-capacity electronic refrigerator, it is not necessary to provide a cooling fan. Various modifications are possible.

[0124]

As is apparent from the above description, according to the first aspect of the present invention, since the outside heat exchanger is composed of the thermosiphon and the radiating fins, a high heat radiating ability can be secured, and the cooling can be performed. Performance can be effectively improved. In particular, the shape of the outer heat transfer block
The dimension of the part that protrudes below the heat radiation surface protrudes upward
Is formed to be larger than the size of the part
ー Heat radiation area of the mosaiphon is relatively low
Since the area can be expanded, the heat radiation performance can be further improved. On the other hand, since the heat absorption capacity of the internal heat exchanger may be lower than the heat radiation ability of the external heat exchanger, the internal heat exchanger is formed by extrusion to have a fin shape. In addition, it is possible to reduce the manufacturing cost of the internal heat exchanger while securing the heat absorption capacity (cooling capacity).

According to the second aspect, a thermosiphon is constituted.
The heating area of the working fluid circulation pipe is inclined with respect to the vertical
If installed in the same way as in claim 1 above,
Heating area by making the height of the heating area of the siphon relatively low
Can be expanded, and the heat radiation performance can be improved.

In the third aspect, the heat transfer block inside the storage is
Since the inside is formed in a trapezoidal shape with long sides, the inside of the warehouse
In addition to reducing the thermal resistance inside the heat transfer block,
Increased heat transfer area on the exchanger side and reduced its contact thermal resistance
it can. In addition, since the long side of the internal heat transfer block is disposed so as to be parallel to the fins of the internal heat exchanger, the fin-shaped internal heat exchanger is formed in a direction perpendicular to the fins. Even if there is a situation where flatness cannot be expected much, it is possible to secure the contact property (heat conductivity) between the two.

According to the fourth aspect, since the internal heat transfer block is divided into the number of thermoelectric elements, the adhesion between each thermoelectric element and the internal heat transfer block can be secured, and the contact thermal resistance between the two can be reduced. .

According to the fifth aspect, the plurality of thermoelectric elements are arranged in parallel with the flow of the cooling air, so that the heat radiation and heat absorption of each thermoelectric element can be performed evenly, and the temperature in the refrigerator can be made uniform. Can be

According to a sixth aspect of the present invention , in a working fluid circulation pipe constituting a thermosiphon, a coil-like portion for reinforcing the press-fit portion from the inside into a portion press-fit into the mounting groove of the heat transfer block inside the refrigerator. When the working fluid circulation pipe is pressed into the mounting groove, the reinforcement of the working fluid circulation pipe can be prevented by the reinforcement member, and the close contact between the outside heat transfer block and the working fluid circulation pipe can be secured. .

[0130] In claim 7, since there is provided a cooling fan for forcibly cooling the Kurasotogawa heat exchanger, can dramatically improve heat dissipation.

[0131] According to claim 8, a cooling fan disposed below the Kurasotogawa heat exchanger, so that the suction downward along the air compartment outer heat exchanger from the upper side of the refrigerator body by rotation of the cooling fan With this configuration, even if the lateral width of the outside heat exchanger is somewhat larger than the lateral width of the cooling fan, the cooling air can be evenly applied to the entire outside heat exchanger.

According to the ninth aspect , the timer means is provided, and the timer means is used to reduce or stop the rotation speed of the cooling fan in an arbitrary time period set in advance. Accordingly, fan noise can be reduced or eliminated at night or the like.

According to the tenth aspect , since the control means for variably controlling the voltage applied to the thermoelectric element is provided, the cooling capacity can be varied as required.

In the eleventh aspect , an internal temperature sensor for detecting the internal temperature is provided, and the voltage applied to the thermoelectric element is variably controlled in accordance with the detected temperature of the internal temperature sensor. Optimum cooling operation according to the condition becomes possible.

In the twelfth aspect , the number of revolutions of the cooling fan is variably controlled according to the temperature detected by the internal temperature sensor, so that fan noise can be relatively reduced.

According to the thirteenth aspect , a switching power supply is employed as a power supply for applying a voltage to the thermoelectric element, and the start / stop of the switching operation of the switching power supply is controlled by the output signal of the internal temperature sensor. Power conversion efficiency is higher than series power supply, power saving is possible, and there is no need to turn on and off the voltage applied to the thermoelectric element with a relay. The problem of deterioration of the contact can be solved, and the problem of self-generated noise caused by turning on and off a large current can also be solved.

In the fourteenth aspect , the switching on / off duty ratio of the switching power supply is variably controlled by the output signal of the internal temperature sensor. Therefore, the internal temperature is fed back to variably control the voltage applied to the thermoelectric element. The control circuit is also simplified.

According to a fifteenth aspect , the thermoelectric element is made of bismuth
By adding silicon monoxide to the antimony-based material at a predetermined ratio, the crystal structure was formed into a granular structure comprising crystal grains of about 1 micron, so that the figure of merit indicating the thermoelectric conversion performance was increased, and the thermoelectric element was improved. The performance of itself can be improved.

In the sixteenth aspect , since the cooling fan for forcibly cooling the outside heat exchanger is provided, the cooling performance can be further improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of an electronic refrigerator according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electronic refrigerator.

FIG. 3 is a back view of the electronic refrigerator with a back cover removed.

FIG. 4 is a cross-sectional view showing a mounting structure of a thermoelectric element and a heat transfer block.

FIG. 5 is a side view (a) and a partially cutaway rear view (b) showing a connection structure between a heat transfer block outside the refrigerator and a working fluid circulation pipe.

FIG. 6 is a top view showing a joint structure between the outer heat transfer block and the working fluid circulation pipe.

FIG. 7 is a graph showing a relationship between a magnification ratio β and a change in thermal resistance in a trapezoidal shape inside-side heat transfer block.

FIG. 8 is an electric circuit diagram

FIG. 9 is a waveform diagram showing a relationship between the inside temperature, the output of the inside temperature sensor, and the output of the operational amplifier.

FIG. 10 is a signal waveform diagram of a main part.

FIG. 11 is an electric circuit diagram showing a second embodiment of the present invention.

FIG. 12 is a signal waveform diagram of a main part.

FIG. 13 is an electric circuit diagram showing a duty ratio determination circuit according to a third embodiment of the present invention.

FIG. 14 is an electric circuit diagram showing a fourth embodiment of the present invention.

FIG. 15 is a time chart showing the relationship between the internal temperature and the voltage applied to the thermoelectric element.

FIG. 16 is a block diagram showing a fifth embodiment of the present invention.

FIG. 17 is a time chart showing the relationship between the internal temperature, the voltage applied to the thermoelectric element, and the rotation speed of the fan motor.

FIG. 18 is a block diagram showing a sixth embodiment of the present invention.

FIG. 19 is a longitudinal sectional side view of an electronic refrigerator according to a seventh embodiment of the present invention.

FIG. 20 is a rear view of the electronic refrigerator with the back cover removed.

FIG. 21 is a cross-sectional view showing a connection structure between an internal heat transfer block and an internal heat exchanger according to an eighth embodiment of the present invention.

FIG. 22 is a rear view showing the connection structure between the outside heat transfer block and the working fluid circulation pipe in the ninth embodiment of the present invention.

FIG. 23 is a longitudinal sectional side view of an electronic refrigerator according to a tenth embodiment of the present invention.

FIG. 24 is a rear view of the electronic refrigerator with the back cover removed.

FIG. 25 is a vertical cross-sectional side view showing a coupling structure between an outside heat transfer block and a working fluid circulation pipe according to an eleventh embodiment of the present invention.

FIG. 26 is a cutaway perspective view showing a coupling structure between a heat transfer block outside a refrigerator and a working fluid circulation pipe according to a twelfth embodiment of the present invention.

[Explanation of symbols]

31 is a refrigerator main body, 35 is a heat insulating wall, 39 is a thermoelectric element, 4
0 is a heat transfer block inside the refrigerator, 41 is a heat transfer block outside the refrigerator,
47 is an internal heat exchanger, 49 is an external heat exchanger, 50 is a thermosiphon, 51 is a radiating fin, 52 is a working fluid circulation pipe, 54 is a mounting groove, 55 is a reinforcing member, 58 is a cooling fan, and 59 is a cooling fan. Fan motor, 73, a switching power supply, 74, a switching element, 89, a control circuit (control means), 91, an internal temperature sensor, 95, an operational amplifier, 10
1 is a duty ratio determination circuit, 103 is an oscillation circuit, 120
Is a comparator, 122 is a duty ratio determination circuit, 14
1 is a timer means, 144 is a brightness detection means, 147 is a cooling fan, 149 is a sound absorbing material, 153 is a liquid reservoir, 154
Is a heater, 157 is a copper pipe, 158 is an aluminum pipe,
160 is a charge pipe, 163 is a heat transfer block outside the refrigerator, and 164 is a working fluid circulation pipe.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Shuyo 1-6 Ota Toshiba-cho, Ibaraki-shi, Osaka Inside the Toshiba Osaka Plant (72) Inventor Tomoyasu Saeki 1-6 Ota-Toshiba-cho, Ibaraki-shi, Osaka (56) References JP-A-4-288857 (JP, A) JP-A-4-126973 (JP, A) JP-A-61-184372 (JP, A) Jpn. (JP, U) JP-A 61-104157 (JP, U) JP-A 2-120684 (JP, U) JP-A 3-18478 (JP, U) JP-A 41-17099 (JP, Y1) Table 1986-501941 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 21/02 F25D 11/00 101 F25D 17/06 312 F25D 19/00 550

Claims (16)

(57) [Claims] 1. A refrigerator body constituted by a heat insulating wall,
A thermoelectric element provided in the refrigerator main body and having a heat absorbing surface on the inside of the refrigerator and a heat dissipation surface on the outside of the refrigerator; a heat transfer block inside the refrigerator disposed on the heat absorbing surface side of the thermoelectric element so as to transfer heat; A fin-shaped interior heat exchanger formed by extrusion and arranged to transfer heat absorbed and exchanged to the interior heat transfer block; and an fin-shaped interior heat exchanger disposed so as to be able to conduct heat to the heat dissipation surface side of the thermoelectric element. Heat transfer block, a thermosiphon for transferring heat absorbed by exchanging heat with the heat transfer block to a heat dissipation area by a circulating action of a working fluid, and a heat dissipation fin provided in a heat dissipation area of the thermosiphon and a compartment outer heat exchanger consisting of, the chamber outer heat transfer block, below the radiating surface of the thermoelectric element
The size of the part protruding upward is smaller than the size of the part protruding upward.
An electronic refrigerator characterized by being formed so as to have a larger size . 2. A refrigerator body constituted by a heat insulating wall;
A thermoelectric element provided in the refrigerator main body and having a heat absorbing surface on the inside of the refrigerator and a heat dissipation surface on the outside of the refrigerator; a heat transfer block inside the refrigerator disposed on the heat absorbing surface side of the thermoelectric element so as to transfer heat; is arranged to heat transfer the heat absorbed by replacing the box inner heat transfer block off formed by extrusion
A compartment inner heat exchanger fin shape, radiating surface of the thermoelectric element
Outside heat transfer block arranged to be able to transfer heat to
The working fluid absorbs the heat absorbed by exchanging heat with the outside heat transfer block.
Thermosyphon and transport to the heat radiation area by the circulation action of
Radiating filter provided in the radiating area of this thermosiphon.
And a working fluid circulation pipe constituting the thermosiphon,
The heating area in contact with the outside heat transfer block is vertical
Characterized in that it is mounted to be inclined with respect to
Electronic refrigerator that. 3. A refrigerator body constituted by a heat insulating wall;
The inside of the refrigerator is provided as a heat-absorbing surface and the outside of the refrigerator is
A thermoelectric element and the heat radiating surface, heat absorption heat side of the thermoelectric element
Heat transfer block inside the refrigerator and air inside the refrigerator
The heat absorbed by the heat exchange with the
Extruded and formed to transmit.
And a heat exchanger for promoting heat radiation from the thermoelectric element.
A heat-exchanger outside the refrigerator, wherein the heat-transfer block inside the refrigerator has a trapezoidal shape in which the inside of the refrigerator has a long side.
Fin of the internal heat exchanger
Characterized by being arranged in parallel with
Child refrigerator. 4. The method according to claim 1 , wherein
An electronic refrigerator, wherein a plurality of thermoelectric elements are provided, and the internal heat transfer block is divided into the number of the thermoelectric elements. 5. The electronic refrigerator according to claim 4, wherein the plurality of thermoelectric elements are arranged in parallel with the flow of the cooling air. 6. The thermosimeter according to claim 1, wherein
The working fluid circulation pipe that constitutes the
Press-fit into the mounting groove formed in the
The part of the body circulation pipe that is pressed into the mounting groove
Has a coiled reinforcement that reinforces the press-fitted part from the inside
An electronic refrigerator having a member inserted therein . 7. The method according to claim 1, wherein
A cooling fan is provided to forcibly cool the outside heat exchanger.
An electronic refrigerator. 8. The cooling fan according to claim 7, wherein the cooling fan is outside the refrigerator.
Disposed below the side heat exchanger, to allow the cooling fan to rotate.
More air from the upper part of the refrigerator body to the outside heat exchanger
It is configured to inhale downward along
Electronic refrigerator and butterflies. 9. The method according to claim 7, wherein
At any time, reduce or stop the speed of the cooling fan.
An electronic refrigerator provided with timer means for stopping the operation. 10. The scent according to claim 1, wherein
Control means for variably controlling the voltage applied to the thermoelectric element
An electronic refrigerator, which is provided . 11. The method according to claim 10, wherein the temperature in the refrigerator is detected.
An internal temperature sensor for controlling the temperature of the internal
Variable voltage applied to the thermoelectric element according to the temperature detected by the sensor
An electronic refrigerator characterized by controlling . 12. The heat exchanger outside the warehouse according to claim 11,
A cooling fan for forcibly cooling the inside of the refrigerator.
The rotation speed of the cooling fan according to the temperature detected by the temperature sensor.
An electronic refrigerator characterized by variable control . 13. Any odor of claims 1 to 3
A switching power supply for applying voltage to the thermoelectric element,
An internal temperature sensor for detecting the internal temperature.
Switch of the switching power supply according to the output signal of the
That the start / stop of the switching operation is controlled.
Electronic refrigerator characterized by the following . 14. The internal temperature sensor according to claim 13,
Switching output of the switching power supply
The on-off duty ratio is variably controlled.
Electronic refrigerator and butterflies. 15. A refrigerator body constituted by a heat insulating wall.
And the outside of the refrigerator is provided with the inside of the refrigerator as a heat-absorbing surface.
Thermoelectric element whose side is the heat dissipation surface, and the heat absorbing surface side of this thermoelectric element
Heat transfer block arranged inside the refrigerator so that heat can be transferred to the refrigerator
The heat transfer block on the inside of the refrigerator that absorbs heat absorbed by heat exchange with air
An internal heat exchanger arranged to transfer heat to the
An external heat exchanger that promotes heat radiation of the thermoelectric element
The thermoelectric element is oxidized to bismuth / antimony-based material.
By adding silicon at a predetermined ratio, the crystal structure
Formed into a granular structure consisting of crystal grains before and after
An electronic refrigerator, comprising: 16. The external heat exchanger according to claim 15,
A cooling fan for forced cooling
And an electronic refrigerator.