JP2827461B2 - Electronic refrigerator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic refrigerator.

[Conventional technology]

DESCRIPTION OF RELATED ART Conventionally, as shown in Unexamined-Japanese-Patent No. 55-41964, the air conditioner for motor vehicles using the electronic refrigerator is known, for example. This uses an electronic refrigerator instead of an evaporator.

[Problems to be solved by the invention]

However, the number of elements with the maximum heat absorption capacity is different from the number of elements with the highest coefficient of performance (efficiency).
In addition, if the optimum design is performed with priority on the coefficient of performance, the heat absorbing ability is sacrificed.

An object of the present invention is to provide an electronic refrigeration apparatus that can perform an optimal operation in consideration of capacity and efficiency.

[Means for Solving the Problems] The present invention, as shown in FIG.
Are connected in series, in the electronic refrigeration apparatus configured to apply a voltage from a power supply to the thermoelectric element M1, a means M2 for changing the number of the thermoelectric elements, and a thermal load detecting means M3 for detecting a thermal load, When the heat load detected by the heat load detecting means M3 is larger than a predetermined heat load, the maximum capacity operation is performed, and when the heat load is smaller than the predetermined heat load, the maximum efficiency operation is performed.
The gist of the present invention is an electronic refrigerating apparatus including a control unit M4 for controlling the number of thermoelectric elements by controlling M2.

[Action]

The control means M4 changes to a maximum capacity operation when the heat load detected by the heat load detection means M3 is larger than the predetermined heat load, and a maximum efficiency operation when the heat load is smaller than the predetermined heat load. Control M2 to change the number of thermoelectric elements.

〔Example〕

Hereinafter, an embodiment in which the present invention is embodied in an air conditioner for a vehicle will be described with reference to the drawings.

As shown in FIG. 2, a blower 2 is arranged in an air duct 1, and inside air or outside air is introduced into the duct 1 via an inside / outside air switching damper 3. An electronic refrigeration unit 4 is arranged in the air duct 1, and the electronic refrigeration unit 4
As shown in the figure, a P-type semiconductor 5, a radiation fin 6, an N-type semiconductor 7, and a heat absorption fin 8 are sequentially laminated. These thermoelectric elements (P-type semiconductor 5 and N-type semiconductor 7) are connected in series. As shown in FIG. 3, a voltage from a battery 10 as a power source for electronic refrigeration is applied to each element via an air conditioner switch 9 and a relay circuit 20 as a changing means. At this time, P → N
By flowing a current in the direction, heat is released at the junction between P and N, and heat is absorbed at the junction between N and P. The electronic refrigerating air conditioner utilizes the heat absorption at this time.

The fins 6 and 8 are provided with a large number of holes to allow ventilation as shown in FIG.

In FIG. 2, the air introduced by the blower 2 is heated by passing through the radiating fins 6 of the electronic refrigeration unit 4 and is discharged from the warm air discharge port 12 through the damper 11 to the outside of the vehicle. The air is cooled by passing through the heat absorbing fins 8 and sent downstream of the air duct 1.

Heat-absorbing fin 8 closest to earth side in electronic refrigeration unit 4
Is provided with a heat absorbing fin thermistor 13, which detects the temperature Tc of the heat absorbing fin 8. Further, a radiation fin thermistor 14 is provided on the radiation fin 6 closest to the ground in the electronic refrigeration unit 4, and the thermistor 14 detects the temperature Th of the radiation fin 6.

A heater core 15 is provided in the air duct 1 downstream of the electronic refrigeration unit 4, and engine coolant is supplied to the heater core 15. And air mix damper 16
The amount of air passing through the heater core 15 is adjusted according to the opening degree. That is, a predetermined amount of air is heated by the heater core 15 so as to reach a temperature set by the occupant.

A heat damper 17, a differential damper 18, and a vent damper 19 are provided downstream of the heater core 15 in the air duct 1, and heat-exchanged air is blown into the vehicle compartment from each outlet in accordance with a set mode.

As shown in FIG. 3, the relay circuit 20 is composed of a number of relay switches (only one is shown in FIG. 3), and the number of thermoelectric elements for applying the voltage of the battery 10 by the opening / closing operation of each relay switch. Can be changed.

A microcomputer (hereinafter, referred to as a microcomputer) 21 as a control means inputs a signal from the heat sink fin thermistor 13 and a signal from the heat radiation fin thermistor 14. Also, the microcomputer 21 receives a battery voltage detection signal from the battery voltage detection sensor to detect the battery voltage, and receives an indoor temperature detection signal from the vehicle interior temperature detection sensor as heat load detecting means to input the battery temperature detection signal from the vehicle interior. Detect temperature. Further, the microcomputer 21 drives and controls the relay circuit 20 to change the number of thermoelectric elements to which the battery voltage is applied.
As shown in FIG. 3, the thermoelectric element is composed of a heat radiation fin 6, a P-type semiconductor 5, a heat absorbing fin 8, and an N-type semiconductor 7, and the number of thermoelectric elements is changed in this unit.

Next, the operation of the automotive air conditioner thus configured will be described with reference to FIG. At this time, as shown in FIG. 5, the room temperature TR is changed to a target room temperature T2 (for example, 25 ° C.).
The case where the cool down is performed will be described.

When the air conditioner switch 9 is turned on in step 101, the microcomputer 21 takes in the air temperature TR in the vehicle compartment in step 102. Then, the microcomputer 21 compares the indoor temperature TR with a predetermined temperature T1 (> T2) in step 103, and if the indoor temperature TR is higher than the predetermined temperature T1 (time t0 to t1 in FIG. 5), Since it is determined that the requirement for the performance is higher than the efficiency, the number n of elements is set to a predetermined number n1 (for example, “150”) in step 104. Then, the microcomputer 21 takes in the battery voltage V, the temperature Tc of the heat-absorbing fins 8 and the temperature Th of the heat-radiating fins 6 in Step 105, and in Step 106, finds the optimum number of elements _nQC for the maximum capacity operation. That is, the heat absorption Qc of the thermoelectric element is expressed by the following equation.

Where α is the Seebeck coefficient, ρ is the specific resistance of the element, λ
Is the thermal conductivity, ΔT is Th−Tc, and L / A is the shape factor of the element (A
Is the current passing cross-sectional area of the element [cm ² ], and L is the current passing length of the element [cm]).

As a result, the number of elements n _QC having the maximum capacity operation is expressed by the following equation, the number of elements n _QC from this equation is obtained.

The number of elements n _QC can be obtained from the above equation. At this time, the number after the decimal point is truncated to obtain an integer.

FIG. 6 shows the case where Tc = 10 ° C. and Th = 37 ° C. (ΔT = 27 ° C.).

Then, in step 107, the microcomputer 21 sets the number of elements n and the optimum number of elements n _QC to make the number of elements n the optimum number of elements n _QC.
Are compared with each other in steps 108 and 109, and the process proceeds to step 105. Then, the microcomputer 21 is t0 seconds wait at step 110 the number of elements is the optimum number of elements n _QC, then proceeds to step 102.

On the other hand, the microcomputer 21 determines in step 103 that the indoor temperature TR is lower than the predetermined temperature T1 (the time t in FIG. 5).
After 1), it is determined that the demand for efficiency is higher than the capability, and in step 111, the number n of elements is set to a predetermined number n2 (for example, “270”). Then, the microcomputer 21 determines in step 112 that the battery voltage V, the temperature Tc of the heat absorbing fin 8, and the temperature Th of the heat radiating fin 6.
Is obtained, and in step 113, the optimum number n _cop of elements for _{achieving the} maximum efficiency operation is obtained. That is, the cooling efficiency (coefficient of performance) COP of the thermoelectric element is expressed by the following equation.

As a result, the number of elements n _cop that _achieves the maximum efficiency operation is expressed by the following equation, and the number of elements n _cop is determined by this equation.

Note that the number of elements n _cop is obtained from the above equation, but at this time, it is obtained as an integer by truncating the decimal part.

Then, the microcomputer 21 sets the element number n and the optimum element number n at that time so that the element number n becomes the optimum element number n _{cop in} step 114.
_{The value} is compared with _cop, and addition or subtraction processing of “1” is performed in steps 116 and 117, and the process proceeds to step 112. And microcomputer 21
Waits for t0 seconds in step 117 when the number of elements reaches the optimum number of elements n _cop, and then proceeds to step 102.

As described above, in the present embodiment, the microcomputer 21 determines the room temperature TR.
When the temperature is higher than the predetermined temperature T1, the maximum capacity operation is performed, and when the room temperature TR is lower than the predetermined temperature T1, the relay circuit 20 is controlled to change the number of thermoelectric elements so that the maximum efficiency operation is performed. . That is, when the difference between the detected room temperature TR and the target room temperature T2 is large (the heat load is large), the detected room temperature TR and the target room temperature T2
The number of thermoelectric elements is changed when the difference from the above is small (the heat load is small). As a result, it is possible to perform an optimal operation in consideration of the heat absorption capacity Qc and the coefficient of performance COP.

Note that the present invention is not limited to the above-described embodiment. For example, as shown in FIG. 6, the number of elements n _QC at which the maximum capacity operation is performed under certain conditions is “150”, and the maximum efficiency operation is performed. The number of elements n _cop is 270, and the number of elements n _{QC for} maximum capacity operation is almost 1 of the number of elements n _cop for maximum efficiency operation.
Since the value is / 2, the number of elements of the electronic refrigeration unit 4 may simply be divided into two. That is, as shown in FIG. 7, the current flow is controlled by a relay circuit (dual relay circuit).
The switching is made possible at 22 and when TR ≦ T1, the connection is made as shown by the solid line and all the elements are energized, and when TR> T1, the connection is made as shown by the broken line and half the elements are energized.

Further, the detection of the heat load may be performed by detecting the heat load not only by the indoor temperature but also by the outside air temperature, the amount of solar radiation, or a combination thereof. Further, the power source of the electronic refrigeration may use the power generated by the alternator in addition to the battery.

In addition, in the addition / subtraction processing of the number of elements in steps 108, 109, 115 and 116 in FIG.
The above values may be subjected to addition / subtraction processing. In this case, it is possible to more quickly converge to the target number of elements.

〔The invention's effect〕

As described in detail above, according to the present invention, it is possible to perform an optimal operation in consideration of the capacity and efficiency.

Further, switching between the maximum capacity operation and the maximum efficiency operation can be performed by changing the applied voltage per thermoelectric element, for example, by using a variable resistor. However, in this case, there is a problem that heat is generated by the variable resistor and power is partially consumed. According to the present invention, switching between the maximum capacity operation and the maximum efficiency operation is performed by changing the number of thermoelectric elements. Is performed, and the original power is consumed by the thermoelectric element, so that there is no energy loss.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the claims, FIG. 2 is a configuration diagram of the vehicle air conditioner of the embodiment, FIG. 3 is an electric circuit diagram of the vehicle air conditioner, FIG. 4 is a flowchart, and FIG. FIG. 6 is a diagram showing the relationship between the heat absorption capacity and the coefficient of performance with respect to the number of elements, and FIG. 7 is a configuration diagram of another example of an automotive air conditioner. M1 is thermoelectric element, M2 is change means, M3 is heat load detection means, M4
Is control means.

Continuation of the front page (72) Inventor Yoshitaka Tomatsu 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside of Denso Co., Ltd. .Cl. ⁶ , DB name) F25B 21/02 B60H 1/32 621 H01L 35/28-35/32

Claims (1)

(57) [Claims] 1. An electronic refrigerator in which a plurality of thermoelectric elements are connected in series to apply a voltage from a power supply to the thermoelectric elements. A change means for changing the number of the thermoelectric elements, and detecting a heat load. Heat load detection means, the maximum capacity operation when the heat load detected by the heat load detection means is greater than a predetermined heat load, and the maximum efficiency operation when the heat load is smaller than the predetermined heat load, Control means for controlling the changing means to change the number of the thermoelectric elements.