JPH05172424A - Heat pump device - Google Patents

Abstract

PURPOSE:To enhance usability of a heat pump device utilizing the Peltier effect by constructing the device so as to improve the efficiency of the heat pump device utilizing a thermally unsteady condition and obtain a greater output therefrom. CONSTITUTION:A heat pump device comprises: a heat absorption side device consisting of a P-type semiconductor 2, a copper plate 3 used as an electrode, a copper block 4 having higher thermal conductivity and larger thermal capacity than those of a thermoelectric semiconductor, and heat-exchange fins 5; and a heat radiation side device having the same construction as that of the heat absorption side device. After power is supplied for a fixed period of time in a state that the end faces of the semiconductors are connected electrically with each other, both the devices are separated spatically from each other by a driving motor 11 to insulate heat before the interior of the devices is put into a thermally steady condition and, thereafter, Peltier heat accumulated in the copper blocks used as a heat reservoir is taken out. According to this construction, the thermal efficiency of a heat pump device which utilizes a thermally unsteady condition can be enhanced by 1.3 times, and the cooling output thereof per cycle can be increased by about 3 times.

Description

Detailed Description of the Invention

[0001]

The present invention utilizes the Peltier effect,
The present invention relates to a thermoelectric device useful for an air conditioner that electrically cools or heats.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a basic structure of a heat pump device for converting electricity into heat is an N-type semiconductor or P which is a thermoelectric material by metal plates 14a and 14b also serving as current terminals and a metal plate 15. Type semiconductor 16, 1
7 is sandwiched, a voltage is applied to the metal plates 14a and 14b, and a current is passed through the semiconductors 16 and 17, whereby the metal plates are heated or cooled by the heat generated by the Peltier effect.

In such a conventional heat pump device, since the thermoelectric efficiency determined by the figure of merit of the semiconductors 16 and 17 as thermoelectric materials is limited, a thermoelectric device having higher efficiency is disclosed in Japanese Patent Laid-Open No. 57-198989.
Japanese Patent Laid-Open No. 63-120060 and Japanese Utility Model Laid-Open No. 63-120060 propose a heat pump device having a configuration in which a heat storage agent is combined and a configuration using an unsteady state as shown in FIG.

As shown in FIG. 5, this heat pump device has a bulky thermoelectric material 19 on a base 18a as a heat absorbing side, and a copper plate 2 which also serves as electrodes and heat exchange fins.
0 is electrically connected, and similarly, the heat dissipation side is electrically connected to the thermoelectric material 21 and the copper plate 22 so as to face the heat absorption side. Further, by attaching the drive motor 23 to the base portion 18b, it is possible to easily connect and disconnect the end faces 24 of both thermoelectric materials.

When a current is first applied to this thermoelectric device in a state where the end faces 24 are in contact with each other, Peltier heat is generated at the copper plate interface of each thermoelectric material. Before the inside of the thermoelectric material immediately after being energized reaches a thermal steady state, the driving motor 23 separates the thermoelectric materials on the heat absorption side and the heat radiation side by the end face 24 to insulate each other from heat, thereby suppressing loss of Peltier heat due to heat conduction. It is configured for efficiency.

[0006]

However, in such a so-called unsteady device, the thermoelectric materials 19 and 2 are energized when energized.
1, the temperature locally rises or falls at the interface between the copper plate 20 and the copper plate 20, 22 and the semiconductor 19, which is a thermoelectric material,
The temperature difference between the two end faces of 21 is very large compared to a stationary device. As a result, the semiconductors 19 and 2 which are thermoelectric materials
Although the loss of Peltier heat due to heat conduction between 1 was reduced, the efficiency of the entire device did not become very high. Further, there is a problem that the cooling output for one cycle of energization and disconnection depends on the heat capacity of the semiconductor, which is a thermoelectric material, and therefore cannot be set too high.

The present invention solves such a problem, and an object of the present invention is to provide a transient device having high thermal efficiency.

[0008]

In order to solve such a problem, the present invention is directed to the thermoelectric material of the current inflow part and the current outflow part of the unsteady thermoelectric device having the conventional structure, and the heat conduction to the outside. The efficiency of the entire device is increased by disposing a material having a high rate as a heat reservoir. Further, as a heat reservoir, a latent heat storage material having a sufficiently high thermal contact property with the Peltier heat generating portion is arranged to increase the overall heat capacity, thereby increasing the cooling output.

[0009]

According to this structure, since the Peltier heat generated in the current inflow portion and the current outflow portion is quickly moved to the heat reservoir having large thermal conductivity by disposing the heat reservoir, both ends of the thermoelectric material are energized during energization. The temperature difference between the surfaces does not become larger than necessary. As a result, it is possible to suppress the extra power for energizing against the thermoelectromotive force due to the temperature difference between both end faces of the thermoelectric material, and to improve the overall efficiency.

Further, by using a latent heat storage material for this heat reservoir, the heat capacity of the heat reservoir can be increased and the amount of current during energization can be increased, so that the cooling output and efficiency can be further increased.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat pump device according to an embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show the configuration of the heat pump device of this embodiment. As shown in the figure, first, as a thermoelectric material on the heat absorption side, Bi _{2 is} placed on the base 1a.
P-type semiconductor made of Te ₃ -Sb ₂ Te ₃ alloy (thickness 3 m
m) 2 and a copper plate used as an electrode (thickness 0.5 m
m) 3 was electrically connected. Further, a copper block (thickness: 6 mm) 4 was provided on the copper plate as a heat reservoir, and a heat exchange fin 5 was provided thereon. Further, the blower fan 6 provided on the base 1a blows air to the heat exchange fins 5,
Increased heat exchange efficiency. Similarly, the P-type semiconductor 7, the copper plate 8, the copper block 9, and the heat exchange fin 10 are formed so that the heat radiation side faces the heat absorption side. Drive motor 1 on base 1b
1 is attached so that the heat absorption side semiconductor 2 and the heat radiation side semiconductor 7 can be easily connected and disconnected.

Next, the operation of the heat pump device configured as described above will be described. First, as shown in FIG. 1, a current of 10 A / cm ² was passed from the heat absorbing side semiconductor 2 to the heat radiating side semiconductor 7 while the heat absorbing side semiconductor 2 and the heat radiating side semiconductor 7 were connected. Next, as shown in FIG. 2, when 3 seconds have passed after energization, the heat absorbing side and heat radiating side semiconductors 2 and 7 were separated from each other by the drive motor 11 to insulate each other. When the ambient temperature is 20 ° C., the endothermic semiconductor 2 is 16.
The temperature was 0 ° C., the heat radiation side semiconductor 7 was 23.5 ° C., and the cooling efficiency (COP) was about 7.5. Next, when the current was set to 30 A / cm ² and a pulse was applied for about 0.4 seconds to connect and disconnect the semiconductors in synchronization with the current pulse, the semiconductor 2 on the heat absorption side had a temperature of 16.5 ° C. after reaching equilibrium. ,
The temperature of the heat radiation side semiconductor 7 was 26.0 ° C. The efficiency at this time was improved by about 1.3 times as compared with the conventional non-steady-state thermoelectric device having a configuration in which the copper block as the heat reservoir is not provided.

The separated heat-absorbing-side and heat-dissipating-side copper blocks were sufficiently exchanged with the object to be cooled such as the atmosphere or the object to be heated by the heat exchange fins, and then repeatedly connected, energized, and disconnected. Furthermore, the relationship between the thickness of the copper block used as a heat reservoir and the efficiency of the entire device was examined by comparing it with a conventional unsteady thermoelectric device having no copper block. When the same temperature difference was applied, the efficiency increased as the copper block was thickened, but the efficiency decreased when the thickness exceeded 6 mm. As a result, it was found that there is an optimum thickness determined by the figure of merit, the shape, the current density of the flowing current, and the conduction time of the thermoelectric semiconductor used.

Next, in the structure shown in FIG. 3, an attempt was made to increase the capacity of the heat reservoir to increase the efficiency and output of the device. The copper foam 12 was disposed in thermal contact with the copper plate 3 on the heat absorption side. The copper foam 12 contained therein open cells having a diameter of 100 to 500 μm, and in this example, the open cells were used by being filled with paraffin having a melting point of 15 ° C. as a latent heat storage material. By using such a copper foam, it becomes possible to rapidly exchange heat between the latent heat storage material and the thermoelectric semiconductor. Further, it was possible to prevent the problems peculiar to the latent heat storage material, that is, the phenomenon of overcooling and overheating. The copper foam 13 on the heat radiation side was filled with paraffin having a melting point of 24 ° C. as a latent heat storage material. The thickness of both of these copper foams was about 5 mm. As a result of conducting an experiment by changing the density of the current flowing in the unsteady device provided with such a latent heat storage material and the energization time, the cooling output obtained in one cycle (connection, energization, disconnection) Could be increased about 3 times.

[0015]

As is clear from the above description of the embodiments, according to the present invention, a material having a large thermal conductivity outside the thermoelectric material of the current inflow portion and the current outflow portion of the unsteady thermoelectric device. By arranging as a heat reservoir,
It is designed to improve the efficiency of the entire device. Further, as a heat reservoir, a latent heat storage material having a sufficiently high thermal contact property with the Peltier heat generating portion is provided to increase the overall heat capacity, thereby increasing the thermal efficiency of the heat pump device using a thermal unsteady state. It is possible to increase the cooling output per cycle by about 3 times by about 3 times.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a heat pump device according to an embodiment of the present invention when energized.

FIG. 2 is a cross-sectional view showing the configuration of the heat pump device when separated.

FIG. 3 is a cross-sectional view showing the configuration of a heat pump device using the latent heat storage material.

FIG. 4 is a sectional view showing the configuration of a conventional heat pump device.

FIG. 5 is a cross-sectional view showing a configuration of a heat pump device using the same thermal unsteady state.

[Explanation of symbols]

 1a, 1b Base 2, 7 P-type semiconductor 3, 8 Copper plate 4, 9 Copper block 5, 10 Heat exchange fin 6 Blower fan 11 Drive motor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Nakagiri 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A heat pump device having a structure in which an electric current is passed through a thermoelectric material having a Peltier effect to insulate a current inflow portion and a current outflow portion of the thermoelectric material before the inside of the thermoelectric material reaches a thermal steady state, A heat pump device in which a material having a thermal conductivity higher than that of the thermoelectric material is arranged as a heat reservoir outside the thermoelectric material in either or both of the current inflow portion and the current outflow portion. 2. The heat pump device according to claim 1, further comprising a latent heat storage material as a heat reservoir arranged outside the thermoelectric material of either or both of the current inflow portion and the current outflow portion.