JPH11173727A - Electronic refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise and save power in an electronic refrigerator having the high voltage and low voltage operations of the applied voltage of a Peltier element and high cooling power obtained by rotating a fan motor for a radiator. SOLUTION: Day and night are set by a timer and a human-body detecting sensor 17 detects whether or not a person is present in surroundings to stop the operation of a fan motor 15 for a radiator when a person is present in the periphery of an electronic refrigerator at night or in the day. In this case, the applied voltage of a Poltier element 8 is raised higher than a rating to operate under high voltage and compensate for the deterioration of the quantity of heat absorption. When a person in not present in the periphery of the refrigerator in the day, the Peltier element 8 is operated under the high applied voltage and the fan motor 15 is operated app under the high applied voltage. Thus, a silent operation can be carried out without loweing cooling power and the refrigerator can be installed in a position requiring a silent operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an electronic refrigerator in which a voltage applied to a peltier element and a fan motor for a radiator is controlled to reduce noise and save power.

[0002]

2. Description of the Related Art In an electronic refrigerator, a current I and a voltage Vp for generating a desired thermoelectromotive force E are applied between electrodes of a Peltier element, so that a low temperature T is applied to a heat absorbing surface of the Peltier element.
E: A high temperature TH is generated on the heat radiating surface, and the inside of the refrigerator is cooled by obtaining a heat absorption QE represented by the following equation.

[0003] QE = EITE-K (TH- TE) -1 / 2RI 2 where K is the thermal conductivity coefficient between the electrodes of the Peltier element, R represents the electrical resistance of the Peltier element, RI ² is Joule heat.

Therefore, when an applied voltage VP is applied between the electrodes of the Peltier element, an endothermic amount of EITE is generated on the heat absorbing surface, and at the same time, K is transferred from the high-temperature heat releasing surface to the low-temperature heat absorbing surface.
(TH-TE) of the conductive heat enters, half heat Joule heat RI ² is to enter the heat absorption side generated further Peltier element.

[0005] K for (TH-TE) and 1 / 2RI ² denotes a heat amount which does not contribute to the cooling of the refrigerator, the heat dissipation surface temperature TH becomes high heat dissipation and to increase the voltage applied between the electrodes of the Peltier element K (TH-TE) increases and the total heat absorption on the heat absorbing surface decreases. Therefore, the radiation surface temperature T
It is necessary to make H as low as possible, and in the conventional electronic refrigerator, a radiator that is in contact with the heat radiating surface with reduced thermal resistance is provided. In order to improve the performance, a fan motor for a radiator is provided.

As a known example of a conventional electronic refrigerator,
JP-A-4-174269, JP-A-4-126973
And Japanese Patent Application Laid-Open No. Hei 5-310454.

[0007]

In order to obtain a large cooling power in an electronic refrigerator, it is necessary to lower the temperature of the heat radiating surface of the Peltier element. Must increase. As a quick method, the size of the radiator may be increased, but in this case, the size of the electronic refrigerator becomes large, and a compact electronic refrigerator cannot be obtained. Therefore, a method in which the radiator is made smaller and a fan motor for the radiator is used has been conventionally adopted.
However, if a fan motor for a radiator is used, noise generated from the fan and the fan motor cannot be used to take advantage of the quietness of the electronic refrigerator by not using a compressor. Alternatively, there is a problem that it cannot be installed in a bedroom or the like of a general home.

Further, when the applied voltage to the Peltier element is increased to obtain a large cooling power, the power consumption is increased. Conversely, when the applied voltage to the Peltier element is reduced to save power, the desired internal temperature is reduced. There was also a problem that it could not be obtained.

[0009] Further, in hospital wards, since a quiet sound is required during a predetermined resting time even in the daytime, there is a problem that if the fan motor is operated during this time, the silent sound cannot be obtained.

[0010]

SUMMARY OF THE INVENTION An electronic refrigerator according to the present invention has been made to solve the above problems.

That is, as in claim 1.

By turning a fan motor for a radiator, a large cooling power can be obtained, and an electronic refrigerator in which the applied voltage of a Peltier element operates at a high voltage and a low voltage.

Furthermore, as in claim 2.

In order to save power and reduce noise, the applied voltage of the Peltier element is set at two levels, high voltage and low voltage. If the ambient temperature is high and the internal temperature is higher than the set temperature, High-voltage operation or high-voltage operation and low-voltage operation are alternately performed until the temperature in the refrigerator decreases.If the ambient temperature is low and the temperature in the refrigerator is close to the set temperature, only low-voltage operation is performed. In order to obtain the temperature inside the chamber, the low temperature side (OFF
) Is set to the high temperature (ON temperature) of the internal temperature sensor in the low voltage operation. As a result, power consumption and noise can be reduced, and a set internal temperature can be secured.

Further, when a person is present around the refrigerator at night or in the daytime for silence, the fan motor is stopped by a timer or a human detection sensor circuit to silence the Peltier device. The system is operated at a high applied voltage to eliminate noise. In addition, the operation of the fan motor is provided with a silence switch that automatically returns after a predetermined time has elapsed, and the input mode of the silence switch is stored, and the operation is performed in this input mode at the next operation. Thereby, silence can be obtained without any trouble at any time.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a longitudinal sectional view of a main part of an electronic refrigerator according to the present invention. FIG. 2 is a block diagram showing a first embodiment of the present invention. FIG.
FIG. 4 is a diagram showing a relationship between a Peltier element and a voltage applied to a radiator fan motor when a person is around the refrigerator during daytime, when there is no person around the refrigerator, and at night in the first embodiment. FIG. 4 is a diagram showing a relationship between a Peltier element and a voltage applied to a heat-dissipating fan motor during a daytime energy saving operation and a normal operation in the second embodiment. FIG.
FIG. 6 is a diagram showing a relationship between a Peltier element input and a radiator fan motor input in an operation C in which the applied voltage of the Peltier element is increased and an operation D in which the applied voltage of the Peltier element is decreased. FIG.
FIG. 4 is a diagram showing inputs when the C operation and the D operation are performed alternately.
FIG. 7 shows the applied voltage of the Peltier element in the first and second embodiments,
The figure which shows the relationship between the applied voltage of the fan motor for radiators, and the internal temperature. FIG. 8 is a diagram showing the relationship between the internal temperatures when the C operation and the D operation are performed alternately. FIG. 9 is a block diagram showing the third embodiment.

In FIG. 1, 1 is an inner box, 2 is a soy toyer,
Reference numeral 3 denotes a heat insulating box, 4 denotes a door, 5 denotes a compartment, and 6 denotes an atita. The heat insulating box 3 comprises an inner box 1, a soy toyer 2, and an atoitor 6.
It is formed by filling the space surrounded by with foam insulation. Reference numeral 7 denotes a back cover, and 7a denotes a back space room. The back space room 7a is composed of an atototer 6 of a heat insulating box 3 and upper, lower, left and right sootitas 2 protruding in the depth direction of the atoitor 6.
And a back cover 7 that covers the peripheral end of the soy toita.

Reference numeral 8 denotes a Peltier element. The Peltier element 8 is disposed in a penetrating portion provided on a part of the back surface of the heat insulating box 3, and has a heat absorbing surface 9 on the front surface and a heat radiating surface 10 on the rear surface. Have. 11 is a heat conductor, 12 is a heat absorber, and the heat conductor 11 is in thermal contact with the heat absorption surface 9 of the Peltier element 8.

The heat absorber 12 is in thermal contact with the thermal conductivity 11 and is provided on the back of the refrigerator. Reference numeral 13 denotes a thermosiphon boiling box, which is in thermal contact with the heat radiating surface 10 and forms a part of a radiator 14 made of a thermosiphon. A heating medium such as a refrigerant is sealed in the boiling box 13 of the thermosiphon, and the vapor generated by the boiling flows into the radiator 14, becomes a condensed liquid in the radiator 14, and returns to the boiling box 13 again. I have. Although not shown, a thin sheet made of a foam metal such as copper is adhered to the inner surface of a member constituting the box wall of the Peltier element 8 of the boiling box 13, whereby a minute dent is formed on the heat transfer surface. It is formed to have a structure in which minute bubble nuclei are easily generated, and constitutes a high-performance means for improving the heat transfer coefficient of the boiling portion.

When a current is applied between the electrodes of the Peltier element and an applied voltage is applied, the temperature of the heat absorbing surface 9 is reduced to perform a heat absorbing action, and the heat in the interior 5 is removed by the heat absorber 12 via the heat conductor 11. , The interior 5 is cooled. On the other hand, the Peltier element 8
When electricity is supplied to the box, heat corresponding to the sum of the heat taken from the inside of the compartment and the supplied electricity is dissipated from the heat dissipation surface 10, and the heat is applied to a member constituting the box wall and a thin sheet of foam metal adhered to the inner surface thereof. It is transmitted by heat conduction. The refrigerant in the boiling section box 13 of the thermosiphon boils efficiently by the action of the thin sheet of foamed metal, and high-performance boiling section heat transfer can be realized. Reference numeral 15 denotes a radiator fan motor. The radiator fan 15 is disposed below the radiator 14 so as to face upward, and is provided to promote heat radiation of the radiator 14. Reference numeral 16 denotes a handle, and 17 denotes a human detection sensor. The human detection sensor 17 is provided on the handle 16. Reference numeral 18 denotes a refrigerator temperature sensor, which is provided below the heat absorber 12 in the refrigerator 5.

The first embodiment of the electronic refrigerator according to the present invention will be described with reference to FIGS. 2 and 3. Referring to FIG. 2, a timer and a timer of a human detection sensor circuit are used to set night and day, and a human detection sensor is used. The presence or absence of a person is detected, and at night B or at day B when a person is present around the electronic refrigerator, the operation of the radiator fan motor is stopped to mute the sound. In this case, the voltage applied to the Peltier element is rated (for example, 10
V), operating at a high voltage (for example, 13 V) to compensate for the decrease in heat absorption. That is, the human detection sensor uses a pyroelectric element or the like to catch infrared rays emitted from the human body when there is a person around the refrigerator, and thereby the electric charge generated in the pyroelectric element is transferred to the Peltier element control circuit and the radiator fan motor control circuit. To control the voltage applied to the Peltier element and the voltage applied to the radiator fan motor as shown in FIG. This makes it possible to mute sound at night or in the daytime when there is a person around the electronic refrigerator, so that the electronic refrigerator can be mounted in a hospital room of a hotel or a hospital where quietness is required. In operation A when there is no person around in the daytime, the voltage applied to the Peltier element is high (for example, 13
V), the voltage applied to the radiator fan motor is operated at a high voltage (for example, 12 V). In this operation, a large cooling power is obtained, but noise reduction is not obtained.

Next, a second embodiment of the refrigerator according to the present invention will be described with reference to FIGS. 2 and 4. In order to save power and reduce noise during the day, the voltage applied to the radiator fan motor is low, for example, 7V. 0.7 V, the applied voltage of the Peltier element is set to two steps (for example, 13 V and 5.5 V). In C operation, the applied voltage of the Peltier element is high (for example, 13 V), and the applied voltage of the fan motor for the radiator is low. (For example, 7.7 V), and in D operation, the applied voltage of the Peltier element is low (for example, 5.5 V), and the applied voltage of the radiator fan motor is low (for example, 7.7 V). In the C operation, the low temperature side (OFF temperature) of the internal temperature sensor is set to the D value so that the C operation and the D operation are alternately operated by the energy saving switch circuit of FIG. During operation, the internal temperature sensor It is obtained so as to set the side temperature (ON temperature) at the inside temperature sensor circuit of FIG.

Here, the relationship between the Peltier element applied voltage VP and the peltier element input WP and the relationship between the fan motor applied voltage VP and the fan motor input WF in the C operation and the D operation will be described. Will be described with reference to FIG.

The Peltier element input WP is expressed by the following equation (1) as the difference between the heat radiation amount QH and the heat absorption QE, which is expressed by the thermoelectromotive force E of the Peltier element, the current I, the applied voltage VP, the heat radiation surface temperature TH, When expressed by the heat-absorbing surface temperature TE and the electric resistance R, the expression (2) is obtained. By dividing equation (2) by current I, equation (3) is obtained, and equation (4) of current I is obtained.

WP = QH−QE (1) WP = EI (TH−TE) + RI ² (2) VP = E (TH−TE) + RI (3) I = (VP−E (TH−TE)) / R (4) When the voltage VF applied to the fan motor is increased, the air-side heat transfer coefficient of the radiator increases, the temperature of the radiator decreases, and the heat radiation surface temperature TH also decreases. In this case, when the applied voltage VP, the thermoelectromotive force E, and the electric resistance R are constant, the current I becomes large, and the Peltier element input WP is proportional to the square of the current I in the equation (2). And increase. FIG. 5 shows this relationship in the embodiment. Fan motor applied voltage V
Although the Peltier element input WP changes with F, when the fan motor applied voltage VF = 7.7, the Peltier element applied voltage V
When F is reduced from 13 V to 5.5 V, the Peltier element input WP is reduced by 63 W. On the other hand, the fan motor input WF with respect to the fan motor applied voltage VF is smaller than the Peltier element input WP, and changes less. Therefore, the input (WP + WF) for the C operation is 78.6 W, and the input for the D operation (WP + WF)
WF) is 16.7 W. To reduce the power consumption of the electronic refrigerator, the average input ω can be reduced by reducing the operation time tc of the C operation and increasing the operation time tD of the D operation in FIG. However, if the operation time tc is reduced, the cooling power is reduced. Therefore, the relationship between the internal temperature and the Peltier element applied voltage VP and the fan motor applied voltage VF will be obtained.

The Peltier element voltage VP is represented by the above equation (3), and when the cooling surface temperature TE is obtained from this equation, the following equation (5) is obtained.

TE = TH− (VP−RI) / E (5) Here, when the applied voltage VF of the fan motor is increased, the air-side heat transfer coefficient of the radiator increases, and the temperature of the radiator decreases.
The heat radiation surface temperature TH also decreases. On the other hand, if the applied voltage VP, the thermoelectromotive force E and the electric resistance R are constant in the above equation (4), the current I becomes large, and the term (VP-RI) / E in the above equation (5) becomes large. Applied voltage VF of fan motor
When the temperature rises, the heat absorption surface temperature TE decreases, the temperature of the heat absorber decreases, and the internal temperature Ti also decreases. FIG. 7 shows this relationship in the embodiment. For example, when the applied voltage VP of the Peltier element is 13 V, the internal temperature Ti of the C operation at the fan motor applied voltage VF = 7.7 V becomes 0 ° C., and the applied voltage Vp of the Peltier element is 5.5 V and the fan motor applied voltage is 7.7 V.
The internal temperature Ti of the D operation is 6 ° C. The internal temperature Ti shown here is a no-load state where there is no opening or closing of the door or the like and there is no food or the like in the internal compartment. In a practical state, the internal temperature rises,
The internal temperature set in the no-load state is, for example, an ambient temperature of 30.
It becomes 3-5 degreeC at the time of degreeC. Therefore, it is necessary to alternately perform the C operation and the D operation in order to secure the intended inside temperature.

Therefore, as shown in FIG. 8, the low temperature (OFF temperature = for example, 3 ° C.) of the internal temperature sensor is changed to D in the C operation.
By setting the high temperature (ON temperature = 5 ° C., for example) of the internal temperature sensor during operation, the desired internal temperature (3 to 5) is set.
° C). In this case, since the cooling power of C is superior to the cooling power of D, the operation time of C having a large input is shorter than the operation time of D having a small input, and power can be saved. For example, when the ambient temperature is 30 ° C. or lower, the desired inside temperature (3 to 5 ° C.) can be obtained only by the D operation.

Further, the third embodiment will be described with reference to the block diagram of FIG. 9. In order to temporarily silence, a silence switch is provided for stopping the operation of the radiator fan motor and automatically returning after a predetermined time has elapsed. Things. That is, when the mute switch is pressed, the mute switch circuit is activated, the power is supplied to the radiator fan motor control circuit, the operation of the radiator fan motor stops, and the timer automatically returns after a predetermined time has elapsed. In this case, the Peltier element printing voltage is maintained at a high voltage (for example, 13 V) by the Peltier element control circuit. This makes it possible to cope with the need for temporary silence at a hotel or hospital.

Further, the input mode of the silence switch is stored, and a silence mode memory circuit which can be operated in the input mode at the next operation is provided, so that it is not necessary to press the silence switch every time. As a result, an easy-to-use refrigerator can be provided in hotels and hospitals.

[0032]

In order to obtain a large cooling power in an electronic refrigerator, it is necessary to lower the temperature of the radiating surface of the Peltier element. For this purpose, a radiator that is in thermal contact with the radiating surface is rotated by a radiating fan motor. Heat dissipation is being done.
Since the electronic refrigerator does not use a compressor, it can be operated quietly because it can be operated quietly, but it is often used in places where noise is required. There was a problem.

Therefore, when there is a person around the electronic refrigerator that requires a quieter operation, the operation of the radiating fan motor is stopped,
The Peltier device is operated by raising the applied voltage to a high voltage. As a result, silent operation can be performed without significantly lowering the cooling power, and installation in a place where silence is required is enabled.

Furthermore, if the applied voltage to the Peltier element is increased to obtain a large cooling power, the power consumption increases. Conversely, if the applied voltage to the Peltier element is reduced to save power, the desired internal temperature becomes lower. There was a problem that it could not be obtained.

In order to save power, two levels of high voltage and low voltage are provided for the applied voltage of the Peltier element, and high voltage operation C and low voltage operation D are alternately performed.
Set the low temperature (OFF temperature) of the internal temperature sensor in the high voltage operation C and the high temperature (ON temperature) of the internal temperature sensor in the low voltage operation D so that the set internal temperature can be obtained. did. As a result, the time of the high-voltage operation C in which both the cooling power and the power consumption are large is short, and the time of the low-voltage operation D in which the cooling power and the power consumption are both small is long, so that the energy-saving operation is possible.

Further, there is a problem that silence is required during operation, and silence cannot be obtained if the fan motor is operated during this operation.

Therefore, a silencing switch circuit is provided which stops the operation of the fan motor for generating heat and automatically returns after a predetermined time has elapsed.
N.

[0038] With this arrangement, it is possible to cope with noise during driving. Further, the time period during which the user wants to reduce noise during driving is fixed, but there is an annoyance that the mute switch must be turned on each time.

Therefore, the input mode of the silence switch is stored, and the operation is performed in this input mode at the next operation. This eliminates the hassle of turning on the silence switch each time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an electronic refrigerator according to the present invention.

FIG. 2 is a block diagram showing a first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a Peltier element and a voltage applied to a fan motor for a radiator when there is a person around the refrigerator, when there is no person, and at night.

FIG. 4 is a diagram showing a relationship between a Peltier element and a voltage applied to a radiator fan motor during daytime D operation and C operation in a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a Peltier element input and a radiator fan motor input in an operation C in which the Peltier element applied voltage is increased and an operation D in which the Peltier element applied voltage is decreased.

FIG. 6 is a diagram showing inputs when the C operation and the D operation are performed alternately.

FIG. 7 shows the applied voltage of the Peltier element in the first and second embodiments,
The figure which shows the relationship between the applied voltage of the fan for radiators, and the temperature in a store | warehouse | chamber.

FIG. 8 is a diagram showing the relationship between the internal temperatures when the C operation and the D operation are performed alternately.

FIG. 9 is a block diagram showing a third embodiment.

[Explanation of symbols]

1 ... inner box, 2 ... soy toy, 3 ... heat insulation box, 4 ... door, 5 ...
Inside of the refrigerator, 6 ... Atita, 7 ... Back cover, 7a ... Back space room, 8 ... Peltier element, 9 ... Heat absorbing surface, 10 ... Heat dissipation surface, 1
DESCRIPTION OF SYMBOLS 1 ... Thermal conductor, 12 ... Heat sink, 13 ... Boiling box, 1
4 radiator, 15 radiator fan motor, 16 handle, 17 human detection sensor, 18 internal temperature sensor.

Claims (5)

[Claims] 1. An electronic refrigerator characterized in that a large cooling power is obtained by rotating a fan motor for a radiator, and that the applied voltage of a Peltier element has a high voltage and a low voltage operation. 2. In order to save power and reduce noise, the applied voltage of the Peltier element is set at two levels, high voltage and low voltage, and when the ambient temperature is high and the internal temperature is higher than the set temperature. Performs high-voltage operation or high-voltage operation and low-voltage operation alternately until the inside temperature decreases, and performs only low-voltage operation when the ambient temperature is low and the inside temperature is close to the set temperature. In order to obtain the set internal temperature, the low temperature side of the internal temperature sensor (OFF
2. The electronic refrigerator according to claim 1, wherein the temperature is set to a high temperature side (ON temperature) of the internal temperature sensor in the low voltage operation. 3. A fan motor is stopped by a timer or a human detection sensor circuit when there is a person around the refrigerator or when silencing is required, and a Peltier element is used when the cooling power of the refrigerator is insufficient. 3. The electronic refrigerator according to claim 1, wherein the applied voltage is increased. 4. The operation of the radiator fan motor is stopped,
The electronic refrigerator according to any one of claims 1 to 3, further comprising a mute switch that automatically returns after a predetermined time has elapsed. 5. An electronic refrigerator according to claim 1, wherein said mute switch stores an input mode and operates in the input mode at the next operation.