JP2007155269A - Cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device capable of miniaturizing a module, and reducing noise. <P>SOLUTION: This cooling device comprises a heat receiving portion for cooling a cooled object, a heat radiating portion for cooling a refrigerant, a flow channel connecting the heat receiving portion and the heat radiating portion to move the refrigerant, a refrigerant driving portion for moving the refrigerant in the flow channel, and a thermal storage unit disposed in the flow channel between the heat receiving portion and the heat radiating portion and switching the flow of heat in the direction to conduct heat away from the refrigerant and the flow of heat in the direction to radiate heat to the refrigerant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooling device for cooling a heating element.

  2. Description of the Related Art Conventionally, there is a forced air cooling module in which, for example, a fan and a fin are integrated as a cooling device for cooling an electronic component or the like provided in a notebook computer or the like. The forced air cooling module forcibly cools the heat-generating components by flowing air using a fan through the fins having a cooling unit attached to the CPU.

  Such a forced air cooling module using fins and fans increases the heat flow capacity of the semiconductor elements such as CPUs by increasing the flow rate of air flowing into the housing by the fan or increasing the fins to increase the heat dissipation capacity. Action is taken. In such a method, there is a problem that the cooling module itself is increased in size or noise is increased due to an increase in fan load.

In order to solve such a problem, in Patent Document 1, the heat receiving portion and the heat radiating portion are connected by a flexible pipe, and the refrigerant is driven by a pump in the pipe so that the heat from the semiconductor element is displayed on the display portion. A liquid cooling device for transporting and radiating heat is described.

JP-A-7-142886

  In the conventional cooling device, there is a problem that the size of the module is increased and the noise is increased when the electronic device whose calorific value is further increased is cooled.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a cooling device that can reduce the size and noise of a module.

In order to solve the above problem, the present invention includes a heat receiving unit that cools an object to be cooled,
A heat dissipating part for cooling the refrigerant;
A flow path for connecting the heat receiving portion and the heat radiating portion, and for moving the refrigerant;
A refrigerant driving unit for moving the refrigerant in the flow path;
A heat storage unit that is provided in the flow path between the heat receiving unit and the heat radiating unit and switches a heat flow in a direction to take heat away from the refrigerant and a heat flow in a direction to release heat to the refrigerant; A cooling device is provided.

  The present invention can achieve high cooling efficiency by providing a heat storage unit that switches between a heat flow in a direction to take heat away from the refrigerant and a heat flow in a direction to release heat to the refrigerant between the heat receiving portion and the heat radiating portion. .

  Hereinafter, detailed embodiments of the invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and can be used in various ways without departing from the spirit of the present invention.

Embodiment 1: Refrigerant reciprocates and uses magnetic material FIG. 1 is a schematic view of a cooling device according to an embodiment of the present invention.

  As shown in FIG. 1, in this cooling device, a heat receiving portion 7, a heat storage unit 6, a heat radiating portion 3 and a pump are connected by a pipe line 1 in a loop shape. Refrigerants such as antifreeze, fluorocarbon, and water sealed in the pipe line 1 by a pump that is a refrigerant driving unit are controlled by the control device 2 so as to reciprocate in the pipe line 1. The reciprocating motion of the refrigerant has at least a stroke (movement width) that passes through both the heat radiating unit 3 and the heat receiving unit 7.

  The storage unit is controlled by the control device 2 so as to switch between a heat flow in a direction to take heat away from the refrigerant and a heat flow in a direction to release heat to the refrigerant in synchronization with the reciprocating motion of the refrigerant.

  In FIG. 1, while the refrigerant is moving in the pipe 1 in the direction of the left arrow, a flow of heat is given in the direction of taking heat away from the refrigerant, and while the refrigerant is moving in the direction of the right arrow, the refrigerant is heated. It is controlled to provide heat flow in the direction of discharge.

  FIG. 2 is a schematic diagram of the heat storage unit 2 using the magnetocaloric effect.

  As shown in FIG. 2, in the heat storage unit 2, a magnetic material 11 showing a magnetocaloric effect such as a granular gadolinium alloy is filled in an envelope 14 formed in a tubular shape. The magnetic material 11 is held by a net 12 provided in the envelope 14, and heat exchange is performed between the magnetic material 11 and the refrigerant when the refrigerant passes through the gap of the magnetic material 11. . The mesh 12 holding the magnetic material 11 is formed finer than the grains of the magnetic material so that the magnetic material 11 does not flow out.

  An electromagnet 10 is provided around the envelope 14 and is controlled by the control device 2 so as to apply a magnetic field to the magnetic material 11.

  Here, the magnetocaloric effect is a phenomenon in which a change in the magnetic field inside a substance changes the entropy of the magnetic spin system (electron system responsible for magnetism), thereby causing energy transfer between the electron system and the lattice system. The magnetic material 11 used in the heat storage unit 6 has a property of releasing heat when a magnetic field is applied and absorbing heat when the magnetic field is removed.

  For example, when the refrigerant flows from the heat receiving unit 7 through the heat storage unit 6 to the heat radiating unit 3 by the control device 2 (when the refrigerant flows in the direction of the arrow on the right in FIG. 1), the electromagnet 10 is operated to apply a magnetic field. Then, the electromagnet 10 is stopped in the reverse direction (when the refrigerant flows in the left arrow direction in FIG. 1) to remove the magnetic field. In this case, a refrigerant whose temperature has been increased by exchanging heat with the magnetic material whose temperature has increased due to the magnetocaloric effect is sent to the heat radiating unit 3, and the heat receiving unit 7 is heat-exchanged with the magnetic material whose temperature has been decreased. The refrigerant whose temperature has decreased can be fed, and the cooling efficiency can be improved.

  In FIG. 3, the graph for demonstrating the direction through which the refrigerant | coolant flows in the cooling device of this embodiment and the direction through which calorie | heat amount flows is shown. The horizontal axis represents the time axis, and the vertical axis represents the direction of refrigerant flow and the direction of heat flow. Moreover, practice shows the direction in which the refrigerant flows, and the broken line shows the direction in which the heat flows.

  As shown in FIG. 3, when the refrigerant leaves the heat radiating unit 3 and goes to the heat receiving unit 7 via the heat storage unit 6 (in the direction of the left arrow in FIG. 1), heat flows from the refrigerant to the heat storage unit 6. . That is, the refrigerant is cooled. Further, when the refrigerant flows in the reverse direction (the direction of the right arrow in FIG. 1), heat flows from the heat storage unit 6 to the refrigerant. That is, the refrigerant is warmed.

By such an operation, the refrigerant cooled by the heat radiating unit 3 is cooled by the heat storage unit 6 due to the magnetocaloric effect, and further flows through the heat receiving unit 7 in a state where the temperature is lowered. Further, the temperature of the refrigerant flowing into the heat radiating unit 3 is further increased than the state in which the refrigerant is heated by the heat storage unit 6 due to the magnetocaloric effect and flows out of the heat receiving unit 7. The heat dissipation performance at the heat receiving section 7 is
Q = (Tj−T1) / R1
Q: Heat absorption at the heat receiving part, W
Tj: Temperature of the semiconductor element that generates heat, ° C
T1: Temperature of refrigerant flowing into the heat receiving part, ° C
R1: Thermal resistance from the semiconductor element to the refrigerant flowing through the heat receiving part, ° C / W
It is expressed as

  The thermal resistance R1 is determined by the flow rate of the refrigerant and the shape of the semiconductor package that is the heat receiving part 7 or the heat generating part (which is to be cooled) when convective heat transfer that does not cause vaporization of the refrigerant is dominant. It does not depend on temperature or amount of heat transferred. Therefore, when cooling a semiconductor element having a calorific value Q, the temperature Tj of the element can be lowered by a decrease if T1 is lowered.

Also, when the refrigerant is vaporized in the heat receiving part, the thermal resistance is affected by the temperature and the amount of heat transferred, so the decrease in T1 and the decrease in Tj are not necessarily equal as in convective heat transfer, but the T1 decreases. Then Tj will decrease.
As for the heat radiating part 3, it is apparent that the heat radiating performance is improved if the temperature of the refrigerant flowing through the heat radiating part 3 is increased for the same reason.

  That is, as shown in FIG. 1, by providing a heat storage unit 6 for heat exchange between the magnetic material 11 and the refrigerant between the heat receiving unit 7 and the heat radiating unit 3, both the heat receiving unit 7 and the heat radiating unit 3 are provided. Performance can be improved. This can be improved without increasing the flow rate of the fan 4 in the heat radiating section 3 or increasing the size of the heat radiating section 3.

  As shown in FIG. 2, the magnetic material 11 showing the magnetocaloric effect is a material that releases heat by applying a magnetic field and rises in temperature and removes the magnetic field to absorb the heat and fall in temperature. A material that absorbs heat by application and releases heat when the magnetic field is removed can be used.

Second Embodiment: Thermal Storage Unit Using Peltier Element Next, a cooling device using a Peltier element as the thermal storage unit will be described. Since the basic structure is the same as FIG. 1, it will be described with reference to FIGS.

  FIG. 4 is a top view and a cross-sectional view of a heat storage unit using a Peltier element.

  As shown in FIG. 4, a container having high thermal conductivity such as a metal filled with a heat storage material 21 is connected to a flow path through which a refrigerant flows through a Peltier element 19. In order to promote the transfer of heat between the heat storage material 21 and the Peltier element 19, the heat storage unit 22 includes fins 20 inside.

As the heat storage material, polyethylene glycol, Na ₂ S ₂ O ₃ .5H ₂ O, NaCH ₃ COO.3H ₂ O, or the like is used. The heat storage material stores heat as sensible heat or latent heat. When storing heat as latent heat, for example, when changing from solid to liquid, the volume changes. For this reason, the fin 20 inside the heat storage unit 22 is not fixed to the wall opposite to the Peltier element 19, and the wall surface of the heat storage unit 22 is easily deformed. That is, it has a structure that can easily absorb the volume change of the heat storage material 21.

  The direction of the current flowing through the Peltier element 19 controls which direction the heat flows between the heat storage material 21 and the refrigerant.

  As shown in FIG. 1, when the refrigerant flows from the heat radiating unit 3 toward the heat receiving unit 7, the Peltier element 19 is operated in a direction to cool the refrigerant and heat the heat storage material 21. Conversely, when the refrigerant flows from the heat receiving portion 7 to the heat radiating portion 3, the Peltier element 19 is operated in a direction in which the heat storage material 21 is cooled to heat the refrigerant. By storing and releasing heat in the heat storage material 21 by the operation of the Peltier element 19 in conjunction with the flow direction of the refrigerant, a low temperature refrigerant is used for the heat receiving unit 7 and a high temperature refrigerant is used for the heat radiating unit 3. Can flow. By doing so, the performance of the cooling device can be enhanced.

  Here, the difference when a Peltier element and a magnetic material are used as the heat storage unit will be described.

  Since the Peltier element can easily obtain a larger temperature difference than the magnetic material exhibiting the magnetocaloric effect, the heat transfer area on the inner surface of the heat storage unit can be made smaller than when the magnetic material is used. On the other hand, the loss of the Peltier element bears the heat generated by the loss of the Peltier element at the heat radiating part in addition to the amount of heat moved larger than the magnetocaloric effect. Since magnetic materials transfer heat by applying and removing a magnetic field, they can be operated in a non-contact manner without attaching electric wires to the magnetic material itself, and the granular magnetic material is brought into direct contact with the refrigerant. The configuration as shown in FIG. 2 can be taken.

Embodiment 3: When a refrigerant | coolant flows intermittently in one direction Next, the cooling device in case a refrigerant | coolant flows the inside of a pipe | tube in one direction intermittently is demonstrated.

  FIG. 5 is a schematic diagram of the cooling device in the present embodiment.

  As shown in FIG. 5, an oscillatory flow is generated by the pump 28 such that the refrigerant flows in one direction or stops. When a magnetic material exhibiting a magnetocaloric effect is used for the heat storage unit 26, when the refrigerant is stationary, a magnetic field is applied to the magnetic material housed inside the heat storage unit 26 to release heat and the temperature rises. The released heat is cooled by the flow of air by the fan 31 attached to the heat radiating section 32. The fins 30 are attached to the heat radiating portion 32 in order to enhance the cooling effect. In the heat storage unit 26, when the magnetic field is removed, the magnetic material absorbs heat and the temperature is lowered. At this time, the refrigerant in the pipe line 23 is driven by the pump 28, whereby low-temperature refrigerant is sent to the heat receiving unit. .

  Even when the Peltier element is used for the heat storage unit 26, the same effect can be obtained by the operation of flowing heat from the refrigerant to the heat storage material and cooling the heat storage material by the air flow around the heat storage unit 26.

  In this embodiment, the storage unit 26 and the heat radiating portion 32 are connected by a wind tunnel, and when the fan 31 is driven, an air flow is generated as indicated by reference numeral 25. By doing so, the cooling effect can be further improved.

Embodiment 4: I-type channel FIG. 6 is a schematic diagram of a cooling device using an I-type channel in the present embodiment.

  As shown in FIG. 6, the conduit 40 is not a closed circuit, but is provided with a pump 41 for reciprocating the refrigerant at one end and a refrigerant reservoir 33 with a variable capacity for accumulating the refrigerant at the other end. Other configurations are the same as those described with reference to FIG.

  With such a configuration, the cooling device can be configured by a single pipeline 40 instead of the two pipelines for refrigerant return and return. For example, when a heat receiving unit 34 is attached to a CPU and a heat radiating unit 38 is arranged in a housing in which a display is housed in a notebook personal computer, there is an advantage that only one conduit is required to pass through a hinge portion connecting the display and the main body.

Embodiment 5: Planar Configuration FIG. 7 is a top view and a cross-sectional view showing a cooling structure provided in a plate-like structure such as a semiconductor chip.

  As shown in FIG. 7, a room with a refrigerant inlet / outlet is partitioned by a diaphragm 42, and the refrigerant inlet / outlet on one side is provided in the vicinity of an area 45 that generates heat through a room in which a magnetic material 43 exhibiting a magnetocaloric effect is disposed. It is connected to the side flow path 44. The refrigerant inlet / outlet on the other side is routed through a plate-like structure provided with a cooling structure. In the vicinity of where the diaphragm 42 and the magnetic material 43 are located, an electromagnet 46 using a planar coil is provided. The diaphragm 42 is made of a material having a property of being attracted to the magnet. When a magnetic field is applied by the electromagnet 46, the diaphragm 42 is attracted to the electromagnet 46 and bends, and the refrigerant filled therein is changed from the right side to the left side in FIG. Shed.

  The magnetic material 43 generates heat when a magnetic field is applied, the refrigerant is warmed and flows into the diaphragm 42, and the magnetic material 43 is cooled. The warmed refrigerant collected in the vicinity of the diaphragm 42 and the magnetic material 43 is released via a heat transfer means such as a radiator 48 provided on the bottom surface of the plate-like structure. When the magnetic field is removed, the diaphragm 42 is elastic and returns to its original state, and the temperature of the magnetic material 43 decreases. Therefore, the refrigerant is cooled down to the heat receiving part flow path 44 and cools the heat generating area near the heat receiving part flow path 44.

  With such a configuration, a structure for selectively cooling the heat generating area 45 can be formed in the semiconductor chip.

  As described above, the embodiment of the present invention has been described. However, the refrigerant may be liquid at room temperature and pressure, such as water, antifreeze liquid, oil, and fluorocarbon, or the refrigerant is heated from the liquid phase by being heated by the heat receiving unit or the heat storage unit. It may be one that changes phase to phase.

  Alternatively, air, nitrogen gas, or carbon dioxide may be used as a refrigerant by flowing through a pipeline. In particular, when air is used as the refrigerant, the end face of the pipe line can be opened to the atmosphere instead of the refrigerant reservoir shown in FIG. 6, and the environment can be used to absorb the change in volume of the refrigerant.

The schematic diagram of the cooling device which concerns on embodiment of this invention Sectional drawing of the thermal storage unit of the cooling device which concerns on embodiment of this invention The graph which showed the relationship between the direction through which the refrigerant | coolant flows of the cooling device which concerns on embodiment of this invention, and the direction through which heat flows Sectional drawing of the thermal storage unit of the cooling device which concerns on embodiment of this invention The schematic diagram of the cooling device which concerns on embodiment of this invention The schematic diagram of the cooling device which concerns on embodiment of this invention Sectional drawing of the thermal storage unit of the cooling device which concerns on embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pipe line 2 ... Control apparatus 3 ... Radiating part 4 ... Fan 5 ... Fin 6 ... Radiating unit 7 ... Heat receiving part 8 ... Pump

Claims (7)

A heat receiving part for cooling the object to be cooled;
A heat dissipating part for cooling the refrigerant;
A flow path for connecting the heat receiving portion and the heat radiating portion, and for moving the refrigerant;
A refrigerant driving unit for moving the refrigerant in the flow path;
A heat storage unit that is provided in the flow path between the heat receiving unit and the heat radiating unit and switches a heat flow in a direction to take heat away from the refrigerant and a heat flow in a direction to release heat to the refrigerant; A cooling device characterized by that.   The refrigerant driving means drives the refrigerant to reciprocate in the flow path, and the heat storage unit generates heat flow in a direction to take heat away from the refrigerant, and heat in a direction to release heat to the refrigerant. The cooling device according to claim 1, further comprising a control device that switches the flow so as to synchronize with the reciprocating motion of the refrigerant.   The refrigerant is driven so that the refrigerant intermittently moves in the flow path by the refrigerant driving means, and the heat storage unit is adapted to take heat from the refrigerant and to release heat to the refrigerant. The cooling device according to claim 1, further comprising a control device that switches a heat flow so as to synchronize with the intermittent movement of the refrigerant.   The cooling apparatus according to claim 2, further comprising a refrigerant reservoir for accumulating the refrigerant at an end of the flow path.   The cooling device according to claim 1, wherein the flow path constitutes a closed circuit.   The heat storage unit exhibits a magnetocaloric effect in which the temperature rises by application of a magnetic field and exhibits a magnetocaloric effect in which the temperature decreases by removal of the magnetic field, and a magnetocaloric effect in which the temperature decreases by application of the magnetic field and increases by removal of the magnetic field 6. The cooling device according to claim 1, further comprising one or both of magnetic materials and an electromagnet or permanent magnet for adding and removing a magnetic field to and from the magnetic material.   The cooling device according to claim 1, wherein the heat storage unit further includes a Peltier element and a heat storage material thermally connected to the Peltier element.

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