U.S. patent application number 14/612351 was filed with the patent office on 2015-05-28 for electronic apparatus.
The applicant listed for this patent is Murata Manufacturing Co., Ltd., National University Corporation Chiba University. Invention is credited to Tadamasa MIURA, Hironao OGURA, Yoshiyuki YAMASHITA.
Application Number | 20150144295 14/612351 |
Document ID | / |
Family ID | 50027937 |
Filed Date | 2015-05-28 |
United States Patent
Application |
20150144295 |
Kind Code |
A1 |
MIURA; Tadamasa ; et
al. |
May 28, 2015 |
ELECTRONIC APPARATUS
Abstract
There is provided an electronic apparatus having a novel means
capable of suppressing temperature rise of a heat generating
element. The electronic apparatus (20), which includes a heat
generating element, is provided with a device (or a chemical heat
pump) (10) comprising: a reaction chamber (1) containing a chemical
heat storage material showing an endothermic reaction in response
to heat emitted by the heat generating element (11); a
condensation/evaporation chamber (3) for condensing or evaporating
a condensable component produced from the endothermic reaction of
the chemical heat storage material; and a communication part (5)
communicating the reaction chamber (1) with the
condensation/evaporation chamber (3) such that the condensable
component is movable between the reaction chamber (1) and the
condensation/evaporation chamber (3).
Inventors: |
MIURA; Tadamasa; (Kyoto,
JP) ; YAMASHITA; Yoshiyuki; (Kyoto, JP) ;
OGURA; Hironao; (Chiba, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Murata Manufacturing Co., Ltd.
National University Corporation Chiba University |
Kyoto
Chiba |
|
JP
JP |
|
|
Family ID: |
50027937 |
Appl. No.: |
14/612351 |
Filed: |
February 3, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2013/070478 |
Jul 29, 2013 |
|
|
|
14612351 |
|
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Current U.S.
Class: |
165/10 |
Current CPC
Class: |
Y02E 60/14 20130101;
Y02A 30/27 20180101; F28D 15/0266 20130101; Y02E 60/145 20130101;
F28D 20/003 20130101; G06F 1/206 20130101; G06F 1/203 20130101;
F28D 20/021 20130101; Y02B 30/62 20130101; F25B 17/08 20130101;
Y02E 60/142 20130101; Y02A 30/277 20180101; H05K 7/2029
20130101 |
Class at
Publication: |
165/10 |
International
Class: |
F28D 20/00 20060101
F28D020/00; F28D 20/02 20060101 F28D020/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2012 |
JP |
2012-173042 |
Claims
1. An electronic apparatus comprising: a heat generating element;
and a device comprising: a reaction chamber containing a chemical
heat storage material showing an endothermic reaction in response
to heat emitted by the heat generating element; a
condensation/evaporation chamber for condensing or evaporating a
condensable component produced from the endothermic reaction of the
chemical heat storage material; and a communication part
communicating the reaction chamber with the
condensation/evaporation chamber such that the condensable
component is movable between the reaction chamber and the
condensation/evaporation chamber through the communication
part.
2. The electronic apparatus according to claim 1, wherein the
communication part is provided with a filter allowing gas to pass
through but not substantially allowing solid and liquid to pass
through.
3. The electronic apparatus according to claim 1, wherein the
chemical heat storage material is molded or packed in the reaction
chamber, and a minimum cross-sectional dimension of the molded or
packed chemical heat storage material is larger than a minimum
cross-sectional dimension of the communication part.
4. The electronic apparatus according to claim 1, wherein the
condensation/evaporation chamber contains a material capable of
trapping liquid, or at least a portion of an inner surface of the
condensation/evaporation chamber is made of the material capable of
trapping liquid.
5. The electronic apparatus according to claim 1, wherein the
reaction chamber comprises a portion made of a heat conductive
material, and the portion made of the heat conductive material is
placed in contact with the heat generating element directly or
indirectly.
6. The electronic apparatus according to claim 1, wherein the
electronic apparatus further comprises a heat conductive member,
and the condensation/evaporation chamber comprises a portion made
of a heat conductive material, and the portion made of the heat
conductive material is placed in contact with the heat conductive
member directly or indirectly.
7. The electronic apparatus according to claim 6, the heat
conductive member is selected from the group consisting of a
housing of the electronic apparatus, an exterior of a battery, a
substrate and a display.
8. The electronic apparatus according to claim 1, the heat
generating element is selected from the group consisting of an
integrated circuit, a light emitting element, a field effect
transistor, a motor, a coil, a converter, an inverter and a
capacitor.
9. An electronic apparatus comprising: a first member and a second
member; and a device comprising: a reaction chamber containing a
chemical heat storage material showing an endothermic reaction and
an exothermic reaction reversibly; a condensation/evaporation
chamber for condensing or evaporating a condensable component
produced from the endothermic reaction of the chemical heat storage
material; and a communication part communicating the reaction
chamber with the condensation/evaporation chamber; wherein the
first member is thermally combined with the reaction chamber, and
the condensation/evaporation chamber is thermally combined with the
second member.
10. The electronic apparatus according to claim 9, wherein the
communication part is provided with a filter allowing gas to pass
through but not substantially allowing solid and liquid to pass
through.
11. The electronic apparatus according to claim 9, wherein the
chemical heat storage material is molded or packed in the reaction
chamber, and a minimum cross-sectional dimension of the molded or
packed chemical heat storage material is larger than a minimum
cross-sectional dimension of the communication part.
12. The electronic apparatus according to claim 9, wherein the
condensation/evaporation chamber contains a material capable of
trapping liquid, or at least a portion of an inner surface of the
condensation/evaporation chamber is made of the material capable of
trapping liquid.
13. The electronic apparatus according to claim 9, wherein when a
temperature of the first member is increased and/or a temperature
of the second member is decreased, heat is transferred from the
first member to the reaction chamber, the chemical heat storage
material produces the condensable component by the endothermic
reaction in the reaction chamber, the condensable component moves
in a gaseous state from the reaction chamber to the
condensation/evaporation chamber through the communication part,
the condensable component is condensed in the
condensation/evaporation chamber to generate heat, and the
generated heat is transferred from the condensation/evaporation
chamber to the second member.
14. The electronic apparatus according to claim 9, wherein when a
temperature of the first member is decreased and/or a temperature
of the second member is increased, heat is transferred from the
reaction chamber to the first member, the exothermic reaction
occurs to consume the condensable component in the reaction
chamber, the condensable component in a gaseous state moves from
the condensation/evaporation chamber to the reaction chamber
through the communication part, the condensable component condensed
in the condensation/evaporation chamber gains the heat and
evaporates, and the heat is transferred from the second member to
the condensation/evaporation chamber.
15. The electronic apparatus according to claim 1, wherein the
condensable component is water.
16. An electronic apparatus having a function of suppressing a
temperature rise of a heating generating element, comprising: a
heat generating element; and at least one reaction chamber
containing a chemical heat storage material, wherein heat generated
from the heat generating element is transferred from an outer
surface of the heat generating element to the chemical heat storage
material in the at least one reaction chamber, and the chemical
heat storage material absorbs the heat by a reaction to suppress
the temperature rise of the heat generating element.
17. The electronic apparatus according to claim 16, wherein the
electronic apparatus comprises a first reaction chamber containing
a first chemical heat storage material, and a second reaction
chamber containing a second chemical heat storage material, and a
first communication part communicating the first reaction chamber
with the second reaction chamber, and wherein the first chemical
heat storage material and the second chemical heat storage material
absorb or generate heat by reactions involving a same component,
the first reaction chamber and the second reaction chamber
communicate with each other by a the first communication part to
allow said component to move through the first communication part,
and the heat generated from the heat generating element is
transferred to either the first chemical heat storage material in
the first reaction chamber or the second heat storage material in
the second reaction chamber.
18. The electronic apparatus according to claim 17, wherein the
first chemical heat storage material is molded or packed in the
first reaction chamber, and a minimum cross-sectional dimension of
the molded or packed first chemical heat storage material is larger
than a minimum cross-sectional dimension of the first communication
part.
19. The electronic apparatus according to claim 17, wherein the
second chemical heat storage material is molded or packed in the
second reaction chamber, and a minimum cross-sectional dimension of
the molded or packed second chemical heat storage material is
larger than a minimum cross-sectional dimension of the first
communication part.
20. The electronic apparatus according to claim 17, wherein the
electronic apparatus further comprises a condensation/evaporation
chamber for condensing or evaporating said component, wherein the
condensation/evaporation chamber communicates with the first
communication part between the first reaction chamber and the
second reaction chamber to allow said component to move to and from
the condensation/evaporation chamber.
21. The electronic apparatus according to claim 20, wherein the
electronic apparatus further comprises a second communication part
communicating the condensation/evaporation chamber with the first
communication part, and wherein either the first communication part
or the second communication part is provided with a filter allowing
gas to path through but not substantially allowing solid and liquid
to path through.
22. The electronic apparatus according to claim 17, wherein the
electronic apparatus further comprises a condensation/evaporation
chamber for condensing or evaporating said component, and a third
communication part communicating the condensation/evaporation
chamber with either the first reaction chamber or the second
reaction chamber wherein the condensation/evaporation chamber
communicates with either the first reaction chamber or the second
reaction chamber by the third communication part to allow said
component to move to and from the condensation/evaporation
chamber.
23. The electronic apparatus according to claim 22, the third
communication part is provided with a filter allowing gas to pass
through but not substantially allowing solid and liquid to pass
through.
24. The electronic apparatus according to claim 20, wherein the
condensation/evaporation chamber contains a material capable of
trapping liquid, or at least a portion of an inner surface of the
condensation/evaporation chamber is made of the material capable of
trapping liquid.
25. The electronic apparatus according to claim 20, wherein said
component is water.
26. The electronic apparatus according to claim 1, the chemical
heat storage material shows an endothermic reaction at a
temperature of 30 to 200.degree. C.
27. The electronic apparatus according to claim 1, wherein, in
place of the chemical heat storage material, the reaction chamber
contains at least one heat storage material selected form the group
consisting of zeolite, silica gel, mesoporous silica and activated
carbon.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electronic apparatus,
more particularly to an electronic apparatus including a heat
generating element (or an element or component which generates
heat).
[0003] 2. Description of the Related Art
[0004] With respect to electronic elements installed in an
electronic apparatus, for example, integrated circuit (IC) such as
a central processing unit (CPU), etc., a part of the input energy
is lost by being converted into heat and generating(emitting) the
heat. If the heat generation brings about significant temperature
rise, the electronic element itself may fail and/or other
peripheral components may be adversely affected, so that the
lifetime and reliability of the electronic apparatus may be
impaired. In addition, the heat generation of the electronic
element is undesirable also from the viewpoints of safety and
usability by a user of the electronic apparatus.
[0005] In order to suppress the temperature rise of such a heat
generating element, there are conventionally known methods that a
cooling fan is used to exhaust the heat outside of the electronic
apparatus by forced convection, and that a heat pipe is connected
at its ends respectively to the heat generating element and to a
heat sink or a heat dissipation plate to transport the heat by
using latent heat for evaporation and condensation of a working
fluid in the heat pipe and then to dissipate the heat from the heat
sink or the like (see, for example, Patent Literature 1). These
methods suppress the temperature rise of the heat generating
element by dissipating the heat directly or indirectly from the
heat generating element.
[0006] Patent Literature 1: JP 2001-68883 A
[0007] Patent Literature 2: JP 10-89799 A
[0008] Patent Literature 3: JP 2008-111592 A
BRIEF SUMMARY OF THE INVENTION
[0009] In recent years, as the performance of electronic
apparatuses is getting higher, the number of heat generating
elements installed in one electronic apparatus is increased and the
amount of energy input to the respective heat generating elements
is increased, so that the amount of heat generated in the
electronic apparatus is increased.
[0010] The conventional method using a cooling fan requires
additional energy to drive the cooling fan. Since this method
brings about larger power consumption of the electronic apparatus
to obtain higher heat dissipation capability, it is not preferable.
Fundamentally, with respect to the heat generation which loses
energy, this method intends to radiate the heat by inputting
energy, and therefore it is not efficient. In addition, it requires
a relatively large space to install the cooling fan, so that this
method is not suitable for small electronic apparatuses.
Furthermore, in a case of electronic apparatuses of which the
housing is sealed, e.g. smartphones and tablet devices, it is not
possible that an air flow caused by the cooling fan is emitted
outside of the apparatus.
[0011] Further, the conventional method using a heat pipe may
transport heat promptly, but it requires a heat sink or a heat
dissipation plate to dissipate the heat. It requires a relatively
large space to install the heat sink or the like, so that this
method is not suitable for small electronic apparatuses. Instead of
the heat sink or the like, it may be considered to dissipate heat
to the housing or so of the electronic apparatus. However, since
the size and thickness of electronic apparatuses tend to be
smaller, the surface area of the housing becomes small, so that it
is not possible to obtain a high heat dissipation capability. In
addition, the temperature of the housing is elevated too much,
which is not preferable in terms of safety and usability by a user.
Furthermore, in a case of high-performance mobile apparatuses, e.g.
smartphones, which has a problem of a shorter lifetime of a lithium
ion battery, when heat is transferred to the housing, the ambient
temperature of the lithium ion battery increases, which may lead to
aging deterioration of a battery capacity.
[0012] Under the condition as described in the above, the fact is
that a temperature of each of the heat generating elements is
measured, and the amount of energy input to the heat generating
element is limited when the measured value of the temperature
exceeds a predetermined threshold value. This method is to suppress
the temperature rise of the heat generating element by reducing the
very amount of heat generated by the heat generating element.
However, this method results in interruption of functions of the
heat generating element (e.g. performance of a CPU) in every time
of the temperature rise of the heat generating element, so that
this method is conducted at the expense of the performance of the
electronic apparatus.
[0013] The present invention aims to provide an electronic
apparatus having a novel means capable of suppressing temperature
rise of a heat generating element.
[0014] The present inventors have focused on techniques for storing
and transferring heat by using a chemical reaction, i.e. a chemical
heat pump. Currently, chemical heat pumps are used for the purpose
of waste heat utilization in chemical plants or power plants, and
used in large apparatuses such as a hot-water supply and heating
system in households or a refrigeration car (see, for example,
Patent Literatures 2 and 3). However, a chemical heat pump applied
to an electronic apparatus is not known. The present inventors have
been dedicated to consider based on our unique concept of using a
chemical heat pump as novel means capable of suppressing the
temperature rise of a heat generating element, and thereby have
accomplished the present invention.
[0015] According to the first aspect of the present invention,
there is provided an electronic apparatus comprising:
[0016] a heat generating element; and
[0017] a device comprising: a reaction chamber containing a
chemical heat storage material which shows an endothermic reaction
in response to heat emitted by the heat generating element; a
condensation/evaporation chamber for condensing or evaporating a
condensable component produced from the endothermic reaction of the
chemical heat storage material; and a communication part which
communicates between the reaction chamber and the
condensation/evaporation chamber such that the condensable
component is able to move between the reaction chamber and the
condensation/evaporation chamber through the communication
part.
[0018] The present invention is not limited in any way, but the
device in which a reaction chamber and a condensation/evaporation
chamber communicate with each other by a communication part may be
understood as a so-called chemical heat pump. In this
specification, such a device is also referred to as a chemical heat
pump.
[0019] In one embodiment related to the first aspect of the present
invention, the reaction chamber may comprise a portion made of a
heat conductive material, and the portion made of the heat
conductive material may be placed in contact with the heat
generating element directly or indirectly.
[0020] In place of or in addition to the above embodiment of the
present invention, the electronic apparatus may further comprise a
heat conductive member, and
[0021] the condensation/evaporation chamber may comprise a portion
made of a heat conductive material, and the portion made of the
heat conductive material is placed in contact with the heat
conductive member directly or indirectly.
[0022] The heat conductive member may be selected from the group
consisting of, for example, a housing of the electronic apparatus,
an exterior of a battery, a substrate and a display, but is not
limited thereto.
[0023] The heat generating element may be selected from the group
consisting of, for example, an integrated circuit, a light emitting
element, a field effect transistor, a motor, a coil, a converter,
an inverter and capacitor, but is not limited thereto.
[0024] According to the second aspect of the present invention,
there is provided an electronic apparatus comprising:
[0025] a first member and a second member; and
[0026] a device comprising: a reaction chamber containing a
chemical heat storage material which shows an endothermic reaction
and an exothermic reaction reversibly; a condensation/evaporation
chamber for condensing or evaporating a condensable component
produced from the endothermic reaction of the chemical heat storage
material; and a communication part which communicates between the
reaction chamber and the condensation/evaporation chamber;
[0027] wherein the first member is thermally combined with the
reaction chamber, and the condensation/evaporation chamber is
thermally combined with the second member.
[0028] In the electronic apparatus according to the present
invention, in a case of increase in a temperature of the first
member and/or decrease in a temperature of the second member, heat
can be transferred from the first member to the reaction chamber,
the chemical heat storage material can produce the condensable
component by the endothermic reaction in the reaction chamber, the
condensable component can move in a gaseous state from the reaction
chamber to the condensation/evaporation chamber through the
communication part, the condensable component can be condensed in
the condensation/evaporation chamber to generate heat, and the heat
can be transferred from the condensation/evaporation chamber to the
second member.
[0029] Also in the electronic apparatus according to the present
invention, in a case of decrease in a temperature of the first
member and/or increase in a temperature of the second member, heat
can be transferred from the reaction chamber to the first member,
the exothermic reaction can occur to use the condensable component
in the reaction chamber, the condensable component in a gaseous
state can move from the condensation/evaporation chamber to the
reaction chamber through the communication part, the condensable
component which is condensed in the condensation/evaporation
chamber can evaporate by obtaining heat, and the heat can be
transferred from the second member to the condensation/evaporation
chamber.
[0030] The electronic apparatus related to either or both of the
first and the second aspects of the present invention preferably
has at least one of the following features:
[0031] (i) the communication part is provided with a filter
allowing gas to path through but not substantially allowing solid
and liquid to path through;
[0032] (ii) the chemical heat storage material is molded or packed
in the reaction chamber, the minimum cross-sectional dimension of
the chemical heat storage material which is molded or packed is
larger than the minimum cross-sectional dimension of the
communication part;
[0033] (iii) the condensation/evaporation chamber contains a
material which is able to trap liquid, or at least a portion of an
inner surface of the condensation/evaporation chamber is made of
the material which is able to trap liquid.
[0034] According to such features, even when the electronic
apparatus is rotated or so in a vertical direction and/or a
horizontal direction, it is possible to effectively prevent the
chemical heat storage material (generally in a state of solid or
semisolid) in the reaction chamber from moving from the reaction
chamber to the condensation/evaporation chamber through the
communication part (in cases of the features (i) and (ii)), and it
is also possible to effectively prevent the condensable component
condensed (liquid) in the condensation/evaporation chamber from
moving from the condensation/evaporation chamber to the reaction
chamber through the communication part (in cases of the features
(i) and (iii)), and thereby it becomes possible to effectively
prevent the capability of the device as a chemical heat pump from
being impaired. The above features and effects obtained thereby
address the peculiar problem that solid and liquid matters in the
device may move between the two chambers since the electronic
apparatus of a mobile type is used rotatably or so in a vertical
direction and/or a horizontal direction. The conventional chemical
heat pump is intended to be used while being placed or moved toward
the horizontal direction. The above described problem in the
application of the electronic apparatus have found uniquely by the
present inventors (which is also applied to the third aspect of the
present invention described hereafter).
[0035] According to the third aspect of the present invention,
there is provided an electronic apparatus having a function of
suppressing temperature rise of a heating generating element, which
comprises:
[0036] a heat generating element; and
[0037] at least one reaction chamber containing a chemical heat
storage material,
[0038] wherein heat generated from the heat generating element is
transferred from an outer surface of the heat generating element to
the chemical heat storage material in the at least one reaction
chamber, and the chemical heat storage material absorbs the heat by
a reaction to suppress the temperature rise of the heat generating
element.
[0039] In one embodiment related to the third aspect of the present
invention, the electronic apparatus comprises a first reaction
chamber containing a first chemical heat storage material, and a
second reaction chamber containing a second chemical heat storage
material,
[0040] the first chemical heat storage material and the second
chemical heat storage material absorb or produce heat by reactions
involving the same component,
[0041] the first reaction chamber and the second reaction chamber
communicate with each other by a communication part, allowing the
said component to move through the communication part,
[0042] heat generated by the heat generating element is transferred
to either the first chemical heat storage material in the first
reaction chamber or the second heat storage material in the second
reaction chamber.
[0043] In the above embodiment of the present invention, the
electronic apparatus may further comprise a
condensation/evaporation chamber for condensing or evaporating the
said component,
[0044] wherein the condensation/evaporation chamber may communicate
with the communication part between the first reaction chamber and
the second reaction chamber, allowing the said component to move to
and from the condensation/evaporation chamber.
[0045] Alternatively, in the above embodiment of the present
invention, the electronic apparatus may further comprise a
condensation/evaporation chamber for condensing or evaporating the
said component,
[0046] wherein the condensation/evaporation chamber communicates
with either the first reaction chamber or the second reaction
chamber by another communication part, allowing the said component
to move to and from the condensation/evaporation chamber.
[0047] The electronic apparatus related to the third aspect of the
present invention preferably has at least one of the following
features:
[0048] (i') any of the communication part(s) communicating between
the chambers (the first reaction chamber, the second reaction
chamber and the condensation/evaporation chamber) is provided with
a filter allowing gas to path through but not substantially
allowing solid and liquid to path through;
[0049] (ii') the first chemical heat storage material is molded or
packed in the first reaction chamber, the minimum cross-sectional
dimension of the first chemical heat storage material which is
molded or packed is larger than the minimum cross-sectional
dimension of the communication part (and preferably another
communication part, if present), and/or the second chemical heat
storage material is molded or packed in the second reaction
chamber, the minimum cross-sectional dimension of the second
chemical heat storage material which is molded or packed is larger
than the minimum cross-sectional dimension of the communication
part (and preferably another communication part, if present);
[0050] (iii') the condensation/evaporation chamber contains a
material which is able to trap liquid, or at least a portion of an
inner surface of the condensation/evaporation chamber is made of
the material which is able to trap liquid.
[0051] According to such features, even when the electronic
apparatus is rotated or so in a vertical direction and/or a
horizontal direction, it is possible to effectively prevent the
chemical heat storage material (generally in a state of solid or
semisolid) in the first and/or second reaction chamber from moving
from the first and/or second reaction chamber to the
condensation/evaporation chamber through the communication part (in
cases of the features (i') and (ii')), and it is also possible to
effectively prevent the condensable component condensed (liquid) in
the condensation/evaporation chamber from moving from the
condensation/evaporation chamber to the first and/or second
reaction chamber through the communication part (in cases of the
features (i') and (iii')), and thereby it becomes possible to
effectively prevent the capability of a chemical heat pump composed
of these members from being impaired.
[0052] Throughout all of the aspects of the present invention, the
term "a chemical heat storage material" means a substance that is
able to store heat by endothermic reaction. In the present
invention, the condensable component (a component capable of being
condensed or evaporating in the condensation/evaporation chamber)
generated from the chemical heat storage material by the
endothermic reaction may be water, but not limited thereto.
Alternatively, with respect to the third aspect of the present
invention, the chemical heat storage material may be one which
produces, in place of the condensable component, other component of
phase changeable (e.g. sublimation) by the endothermic reaction. In
this case, the condensation/evaporation chamber functions as a
phase change chamber (e.g. a sublimation chamber) where this
component changes its phase.
[0053] Such a chemical heat storage material preferably shows an
endothermic reaction at a temperature of 30 to 200.degree. C.
[0054] Further, throughout all of the aspects of the present
invention, it is possible to use, in place of the chemical heat
storage material, at least one heat storage material selected form
the group consisting of zeolite, silica gel, mesoporous silica and
activated carbon. Also in this case, it is possible to bring about
effects corresponding to the respective heat storage materials.
[0055] According to the first aspect of the present invention, a
chemical heat pump (or a device wherein a reaction chamber and a
condensation/evaporation chamber communicate with each other by a
communication part) is applied to an electronic apparatus having a
heat generating element, and uses a chemical heat storage material
showing an endothermic reaction by heat generated from the heat
generating element, so that it is possible to draw and store heat
from the heat generating element by the reaction of the chemical
heat storage material when the heat generating element generates
the heat, and thereby to suppress the temperature rise of the heat
generating element. In other words, it is realized to conduct
transfer or leveling of heat at least temporally in the electronic
apparatus.
[0056] According to the second aspect of the present invention, a
chemical heat pump is applied to an electronic apparatus between
the first and the second members, and a reaction chamber and a
condensation/evaporation chamber of the chemical heat pump are
thermally combined with the first and the second members,
respectively, so that it is possible to transfer heat from the
first member to the second member, or from the second member to the
first member while the chemical heat storage material stores or
emits the heat. In other words, it is realized to conduct transfer
of leveling of heat temporally and spatially in the electronic
apparatus.
[0057] According to the third aspect of the present invention, a
reaction chamber containing a chemical heat storage material is
provided to an electronic apparatus having a heat generating
element, so that heat generated from the heat generating element is
conducted from the outer surface of the heat generating element to
the chemical heat storage material contained in the reaction
chamber and the chemical heat storage material absorbs (or stores)
heat by a reaction, and thereby it is possible to suppress the
temperature rise of the heat generating element.
[0058] According to any of the aspects of the present invention, it
is possible to use a chemical reaction of the chemical heat storage
material, and thus to obtain a high capacity of heat storage.
Furthermore, when an amount of the heat generated by the heat
generating element is decreased or reduced, cold energy (or
negative amount of heat) is obtained at the chamber to which the
heat generated by the heat generating element is not directly
conducted (this chamber is typically a condensation/evaporation
chamber, but in a case of the third aspect of the present invention
may comprise one of the first reaction chamber and the second
reaction chamber to which the heat generated by the heat generating
element is not directly conducted). These feathers of obtaining a
high capacity of heat storage and cold energy is significant
characteristics peculiar to the present invention, compared to a
heat pipe using latent heat or a heat transport device using
sensible heat. As chemical heat pumps other than a chemical heat
pump using a chemical reaction, a mechanical heat pump and a heat
pump using an adsorption or absorption reaction are known.
According to the present invention, since it uses a chemical
reaction of the chemical heat storage material, unlike the
mechanical heat pump, the present invention does not require a
large mechanical component having a complicated structure, e.g. a
compressor, and compared with the case of using an absorption or
adsorption reaction, the present invention is able to obtain a
higher capacity of heat storage and to store heat in a wider
temperature range.
[0059] However, the present invention is not limited to those using
a chemical heat storage material, but may widely comprise those
using other heat storage material such as at least one heat storage
material selected from the group consisting of, for example,
zeolite, silica gel, mesoporous silica and activated carbon. Also
in this case, it is possible to bring about effects corresponding
to the respective heat storage materials. Further, compared with
the chemical heat storage material, such heat storage material may
provide advantages of being easy to handle and of simplifying the
structure (for example, it is not necessary to consider prevention
of corrosion).
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0060] FIG. 1 shows a schematic cross-sectional view of an
electronic apparatus according to one embodiment of the present
invention.
[0061] FIG. 2 shows a schematic cross-sectional view of an
electronic apparatus according to other embodiment of the present
invention.
[0062] FIGS. 3A to 3C show schematic top views showing various
modifications of the electronic apparatus according to other
embodiment of the present invention.
[0063] FIG. 4 shows a schematic top view showing one CHP-equipped
example in Examples of the electronic apparatus of the present
invention.
[0064] FIG. 5 shows a schematic top view showing other CHP-equipped
example in Examples of the electronic apparatus of the present
invention.
[0065] FIG. 6 shows a schematic top view showing other CHP-equipped
example in Examples of the electronic apparatus of the present
invention.
[0066] FIG. 7 shows a schematic top view showing other CHP-equipped
example in Examples of the electronic apparatus of the present
invention.
[0067] FIG. 8 shows a schematic cross-sectional view showing a
model used for simulation in a comparative example of the
electronic apparatus of the present invention.
[0068] FIG. 9 shows a schematic cross-sectional view showing a
model used for simulation in one example of the electronic
apparatus of the present invention.
[0069] FIGS. 10A and 10B show a graph and a table showing change in
temperatures of the reaction chamber and the CPU with the passage
of time in the simulation of FIG. 9.
[0070] FIG. 11 shows a schematic cross-sectional view showing a
model used for simulation in other example of the electronic
apparatus of the present invention.
[0071] FIGS. 12A to 12D show schematic cross-sectional views each
showing an exemplary production process of a CHP to be used in an
electronic apparatus in one embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0072] An electronic apparatus in some embodiments of the present
invention will be described in detail with reference to the
drawings, but the present invention is not limited thereto.
[0073] First, the configuration of a chemical heat pump (CHP) as a
device wherein a condensation/evaporation chamber and a reaction
chamber communicate with each other by a communication part will be
described below. In the present embodiment, as shown in FIG. 1, a
chemical heat pump 10 includes a reaction chamber 1 containing a
chemical heat storage material, a condensation/evaporation chamber
3 for condensing or evaporating a condensable component, and a
communication part which communicates therebetween. A chemical
reaction of the chemical heat storage material is a drive source
for transferring heat by the chemical heat pump 10, and the
condensable component is a working medium of the chemical heat pump
10.
[0074] As the chemical heat storage material, any suitable material
may be used as long as it is able to store heat by an endothermic
reaction. According to the principles of the chemical heat pump,
the chemical heat storage material may show an endothermic reaction
and an exothermic reaction which are reversible with each other,
and produce the condensable component from any of these reactions,
but is not limited thereto. The condensable component is a
component which is able to change its phase between a gaseous state
(gas phase) and a liquid state (liquid phase) under the environment
of use.
[0075] In the present embodiment, a chemical heat storage material
that produces a condensable component by an endothermic reaction.
Such a chemical heat storage material may show a dehydration
reaction as the endothermic reaction and show a hydration reaction
as the exothermic reaction. In this case, the condensable component
is water.
[0076] In particular, hydrates of inorganic compounds, inorganic
hydroxides and the like may be used for the chemical heat storage
material described above. More specifically, examples thereof
include hydrates of alkaline earth metal compounds and alkaline
earth metal hydroxides, e.g. hydrates of calcium sulfate, calcium
chloride and so on, and hydroxides of magnesium, calcium and so
on.
[0077] For example, calcium sulfate hemihydrate shows an
endothermic reaction below:
CaSO 4 1 2 H 2 O ( s ) + Q 1 .fwdarw. CaSO 4 ( s ) + 1 2 H 2 O ( g
) ##EQU00001##
[0078] wherein Q.sub.1 is known as approximately 16.7 kJ/mol.
[0079] The endothermic reaction of calcium sulfate hemihydrate may
proceed at, for example, about 50 to 150.degree. C., although it
depends on the various conditions. This is a reversible reaction,
and a reverse reaction with respect to the above described reaction
is the exothermic reaction. Calcium sulfate hemihydrate is in a
solid state (e.g. powder), calcium sulfate is in a solid state, and
water is in a gaseous state.
[0080] Further, for example, calcium chloride hydrate shows an
endothermic reaction below:
CaCl.sub.2.nH.sub.2O(s)+Q.sub.2.fwdarw.CaCl.sub.2(s)+nH.sub.2O(g)
[0081] wherein n is a number of water molecules for hydration,
specifically 1, 2, 4 and 6; Q.sub.2 is known as about 30 to 50
kJ/mol.
[0082] The endothermic reaction of calcium chloride hydrate may
proceed at, for example, about 30 to 150.degree. C., although it
depends on the various conditions. This is a reversible reaction,
and a reverse reaction with respect to the above described reaction
is the exothermic reaction. Calcium chloride hydrate is in a solid
state (e.g. powder), calcium chloride is in a solid state, and
water is in a gaseous state.
[0083] However, it is not limited to the examples above, any
suitable chemical heat storage material (for example, one capable
of generating ammonia) may be used and selected appropriately to
show an endothermic reaction by heat generated from the heat
generating element.
[0084] In a broader concept, the chemical heat storage material
usable in the present invention is preferably one showing the
endothermic reaction at a temperature such as 30 to 200.degree. C.,
and more preferably one showing the endothermic reaction at a
temperature of 40.degree. C. or more, particularly 50.degree. C. or
more, and of 150.degree. C. or less, particularly 120.degree. C. or
less.
[0085] This chemical heat storage material is contained in the
reaction chamber 1. The chemical heat storage material may form,
for example, a solid phase 2a, and there may exist a gas phase 2b
containing a condensable component in the reaction chamber 1. It is
desirable that the pressure in the reaction chamber is
substantially equal to an equilibrium pressure of the exothermic
reaction and the endothermic reaction at a general temperature
environment for use (when the heat generating element is in a
non-heating state).
[0086] On the other hand, in the condensation/evaporation chamber
3, there exists a condensable component as being contained in a gas
phase 4a and a liquid phase 4b. The component which has been
condensed beforehand (e.g. water in a liquid state) may be
contained in the condensation/evaporation chamber, although the
present embodiment is not limited thereto. It is desirable that the
pressure in the condensation/evaporation chamber is substantially
equal to a saturated vapor pressure of the condensable component
(saturated water vapor pressure in the case of water) at a
temperature environment for use.
[0087] The communication part 5 for communicating (or connecting)
between the reaction chamber 1 and the condensation/evaporation
chamber 3 is configured so that the condensable component is
movable between them. More specifically, the condensable component
may move in a gaseous state, and in this case the communication
part 5 is configured to pass gas therethrough. Such a communication
part may be conveniently a tubular member, but is not limited
thereto.
[0088] The communication part 5 may or may not have a valve (not
shown). If the communication part 5 does not have a valve, the
devise has a simple configuration, and the movement of the
condensable component and thus the operation of the chemical heat
pump 10 depend on the progress of the reaction in the reaction
chamber (1) and/or the progress of the phase change in the
condensation/evaporation chamber 3 (typically, the temperature in
the condensation/evaporation chamber 1 and/or the reaction chamber
1). If the communication part 5 has a valve, the movement of the
condensable component and thus the operation of the chemical heat
pump 10 is controllable by opening and closing the valve, and it
becomes possible to manage the transfer of heat and the timing of
heat generation and cooling, and therefore it becomes possible to
provide the electronic apparatus with more elaborate thermal design
for its inside.
[0089] Such chemical heat pump 10 is in a closed system without the
entry and exit of substances, but is formed to enable the entry and
exit of heat through at least the reaction chamber 1, and
preferably the reaction chamber 1 and the condensation/evaporation
chamber 3. In particular, the reaction chamber 1 and preferably the
condensation/evaporation chamber 3 may be at least partially made
of a heat conductive material, respectively. The heat conductive
material is not particularly limited but, for example, may be any
of good heat conductors such as metals (e.g. copper), oxides (e.g.
alumina), nitrides (e.g. aluminum nitride), carbon and so on.
[0090] The chemical heat pump 10 used in the electronic apparatus
of the present embodiment preferably has any of the following
features, either alone or in combination of any two or more:
[0091] (i) the communication part 5 is provided with a filter
allowing gas to path through but not substantially allowing solid
and liquid to path through;
[0092] (ii) the chemical heat storage material is molded or packed
in the reaction chamber 1, the minimum cross-sectional dimension of
the chemical heat storage material which is molded or packed being
larger than the minimum cross-sectional dimension of the
communication part 5;
[0093] (iii) the condensation/evaporation chamber 3 contains a
material capable of trapping liquid, or at least a portion of an
inner surface of the condensation/evaporation chamber 3 is made of
the material capable of trapping liquid.
[0094] Regarding the above (i), as the communication part 5 is
provided with the filter allowing gas to path through but does
substantially allowing solid and liquid to path through, even when
the electronic apparatus 20 is rotated or so in a vertical
direction and/or a horizontal direction, it is possible to
effectively prevent the chemical heat storage material (generally
in a state of solid or semisolid) in the reaction chamber 1 from
moving from the reaction chamber 1 to the condensation/evaporation
chamber 3 through the communication part 5, and it is also possible
to effectively prevent the condensable component condensed (liquid)
in the condensation/evaporation chamber 3 from moving from the
condensation/evaporation chamber 3 to the reaction chamber 1
through the communication part 5.
[0095] Such filter shall be capable of passing gas but does not
substantially allow passage of solid and liquid therethrough. The
words "not substantially allowing solid and liquid to path through"
means that it may passes a small amount of solid and liquid to the
extent not impairing the performance of the chemical heat pump. The
filter is preferably one passing a small amount of liquid but not
passing solid, and more preferably one not passing both liquid and
solid.
[0096] More specifically, the filter preferably has a moisture
permeability of 1,000 g/m.sup.2/24 h or more, particularly of
10,000 g/m.sup.2/24 h (according to JIS L1099, B method, generally
B-1 method), and thereby it is possible to reduce sufficiently the
pressure loss due to the filter. As to non-passage of solid, it is
enough when the chemical heat storage material does not pass
through, and may be appropriately selected depending on the size of
the chemical heat storage material to be used. As to non-passage of
liquid, it is preferable to have a waterproof property of 1,000 mm
or more, and particularly 10,000 mm or more (according to JIS
L1092, A method).
[0097] In particular, for example, it is possible to use a film
(fine pore filter) formed by stretching polytetrafluoroethylene,
which may also be conjugated with polyurethane polymer according to
necessity. Such film is available in the market, for example, under
the trade name of "GORE-TEX" (registered trademark). It is also
possible to use a water-repellent fiber cloth with a polyurethane
coating. Such polyurethane coated cloth is available in the market,
for example, under the trade name of "Entrant GII" (registered
trademark) XT, etc. from Toray Industries, Inc.
[0098] However, the filter is not limited to these examples, and it
is possible to apply the filter with any suitable structure having
a pore size smaller than a water particle and larger than a water
vapor particle/molecule.
[0099] As long as the filter is able to pass gas, but does not
substantially pass solid and liquid, the filter may be provided in
the communication part 5 in any manner. For example, the filter may
be placed so as to fill at least a part of the inner space of the
communication part 5 (preferably, in the vicinity of the reaction
chamber 1), or may be placed so as to cover the opening of the
communication part 5 (preferably, the opening at the side of the
reaction chamber 1).
[0100] Regarding the above (ii), as the chemical heat storage
material is molded or packed in the reaction chamber 1 and the
minimum cross-sectional dimension of the molded or packed chemical
heat storage material is larger than the minimum cross-sectional
dimension of the communication part 5, even when the electronic
apparatus 20 is rotated or so in a vertical direction and/or a
horizontal direction, it is possible to effectively prevent the
chemical heat storage material (generally in a state of solid or
semisolid) in the reaction chamber 1 from moving from the reaction
chamber 1 to the condensation/evaporation chamber 3 through the
communication part 5.
[0101] The chemical heat storage material in the reaction chamber 1
may be molded or packed in any suitable manner. When the chemical
heat storage material is hydrate of an inorganic compound (e.g.
hydrate of calcium chloride or calcium sulfate), the inorganic
compound is solidified by hydration, so that it can be molded using
a mold or the like during solidifying. Further, it is possible to
mix the chemical heat storage material with a resin material and a
solvent etc. if necessary, and mold the resultant composition by
mold pressing or the like (the resin material and, if present, the
solvent etc. can be removed away partially, and preferably mostly,
during the molding). Otherwise, when the chemical heat storage
material is a granular material, the chemical heat storage material
can be packed by using a wrapping material having one or more
openings of which size is smaller than the particle diameter (e.g.
average diameter) of the chemical heat storage material, such as
mesh, net, fabric (e.g. woven or nonwoven fabric), film and the
like. The wrapping material may be made of, for example, metal,
natural or synthetic fibers, a polymer material or the like.
[0102] The chemical heat storage material molded or packed as
described in the above shall have its minimum cross-sectional
dimension which is larger than the minimum cross-sectional
dimension of the communication part 5. The minimum cross-sectional
dimension of the chemical heat storage material packed or molded
means the minimum cross-sectional dimension of the chemical heat
storage material packed or molded in any cross-section. The minimum
cross-sectional dimension of the communication part 5 means the
minimum cross-sectional dimension of the internal space the
communication part in any cross-section, and usually refers to the
size of the narrowest portion of the communication part 5. In other
expressions, this may explained by that when a projected area of
the molded or packed chemical heat storage material is at a minimum
among those of in any direction of projection, the maximum
dimension of the minimum projected area is larger than the minimum
cross-sectional dimension of the inner space of the communication
part 5 which is perpendicular to the center line of the
communication part 5. In summary, it is satisfactory that the
molded or packed chemical heat storage material has a dimension so
that it is not able to pass through the communication part 5. For
example, if an opened size of the opening of the communication part
5 at the side of the reaction chamber 1 (and optionally the opening
at the side of the condensation/evaporation chamber 3) is smaller
than the minimum cross-sectional dimension of the molded or packed
chemical heat storage material, a part between the two openings of
the communication part 5 may have a larger size.
[0103] The molded or packed chemical heat storage material may be
present in the reaction chamber 1. However, for the purpose of
prompt and efficient movement of heat, it is preferably placed in
contact with a position to which the heat from the heat generating
element 11 is transmitted well.
[0104] Regarding the above (iii), as the condensation/evaporation
chamber 3 contains a material capable of trapping liquid or at
least a portion of an inner surface of the condensation/evaporation
chamber 3 is made of the material capable of trapping liquid, even
when the electronic apparatus 20 is rotated or so in a vertical
direction and/or a horizontal direction, it is possible to
effectively prevent the condensable component condensed (liquid) in
the condensation/evaporation chamber 3 from moving from the
condensation/evaporation chamber 3 to the reaction chamber 1
through the communication part 5.
[0105] Such material may be one capable of trapping liquid
reversibly. In particular, porous materials such as ceramics,
zeolites, metals or the like can be used, but is not limited
thereto.
[0106] The material capable of trapping liquid may be contained in
the condensation/evaporation chamber 3 or form a part of the inner
surface of the condensation/evaporation chamber 3. In the former
case, the material capable of trapping liquid is prepared
beforehand and supplied into the condensation/evaporation chamber
3. In the latter case, for example, ceramic or zeolite is
synthesized, for example by hydrothermal synthesis, on the inner
surface of the wall material of the condensation/evaporation
chamber 3 to cover the inner surface. In any case, the material
capable of trapping liquid may exist in or on the inner surface of
the condensation/evaporation chamber 3. However, for the purpose of
prompt and efficient movement of heat, it is preferably placed in
contact with a position from which heat is transmitted well to a
heat conductive member 13.
[0107] The chemical heat pump 10 having such configuration may be
prepared exemplarily as follows, but the present embodiment is not
limited thereto.
[0108] First, referring to FIG. 12A, two metal plates 41a and 41b
are prepared. These metal plates are made preferably of a corrosion
resistant metal such as stainless steel, e.g. SUS, but not limited
thereto. The metal plates 41a and 41b may have a thickness of, for
example, 0.01 mm or more, particularly 0.05 to 0.5 mm. The material
and the thickness of the metal plates 41a and 41b may be the same
as or different from each other.
[0109] Next, as shown in FIG. 12B, the one metal plate 41a is
formed with two protruded portions 43a which correspond to the
reaction chamber 1 and the condensation/evaporation chamber 3. The
dimensions of the protruded portions 43a may be determined
according to the desired dimensions for the reaction chamber 1 and
the condensation/evaporation chamber 3. The height of the protruded
portions 43a may be, for example, 0.1 to 100 mm, particularly 0.3
to 10 mm, and may be the same as or different from each other. On
the other hand, the other metal plate 42b is formed with a recessed
portion 43b which corresponds to the communication part 3. The
dimensions of the recessed portion 43b may be ones which enables
that the communication part 3 is formed to communicate between the
reaction chamber 1 and the condensation/evaporation chamber 3 and
the condensable component is movable through the inside of the
communication part 3. The depth of the recessed portion 43b may be,
for example, 0.1 to 100 mm, particularly 0.3 to 10 mm. The
formation of the protruded and recessed portions 43a, 43b in the
metal plates 41a, 41b may be conducted by applying any suitable
method, for example, spinning, press working, or the like.
[0110] Then, the chemical heat storage material 45 is displaced in
one of the two protruded portions 43a of the metal plate 41, which
correspond to the reaction chamber 1. The chemical heat storage
material 45 is generally in a solid or semisolid state, and may be
in the form of, for example, granules, a sheet or the like. The
chemical heat storage material 45 is preferably molded or packaged
beforehand as describe in the above, although this is not
essential.
[0111] Further, if required, the material capable of trapping
liquid described in the above (e.g. porous material, not shown in
the drawings) is displaced in one of the two protruded portions 43a
of the metal plate 41, which correspond to the
condensation/evaporation chamber 3. Alternatively, the inner
surface of one of the two protruded portions 43a of the metal plate
41 and corresponding to the condensation/evaporation chamber 3 may
be covered by the material capable of trapping liquid as described
in the above.
[0112] On the other hand, a filter 47 allowing gas to path through
but not substantially allowing solid and liquid to path through is
preferably displaced in the recessed portion 43b of the metal plate
41b, although this is also not essential.
[0113] Thereafter, as shown in FIG. 12C, the metal plates 41a, 41b
are superimposed with each other to form an internal space by the
protruded portions 43a and the recessed portion 43b together. As a
result, the outer peripheral and flat surfaces of the metal plates
41a, 41b are in close contact with each other.
[0114] Then, as shown in FIG. 12D, the metal plates 41a, 41b
superimposed with each other are hermetically sealed at the outer
peripheral portion 49. The hermetic sealing is preferably conducted
under a pressure which is desired for the inside of the chemical
heat pump, which is generally a reduced pressure (depending on the
chemical heat storage material used therein), for example, 0.1 to
100,000 Pa, particularly 1.0 to 10,000 Pa (absolute pressure). The
hermetic sealing may be conducted by applying any suitable method,
and the applicable methods are, for example, laser welding, arc
welding, resistance welding, gas welding, brazing, and so on. After
the hermetic sealing, unnecessary edges of the outer peripheral
portion 49 may be optionally removed off by punching operation or
the like.
[0115] As described in the above, the chemical heat pump 10 can be
produced. However, the production method described above is merely
exemplary, and the chemical heat pump which is applicable to the
present invention can be produced according to any suitable
method.
[0116] Next, the chemical heat pump 10 having the configuration as
described above is incorporated in the electronic apparatus 20
having the heat generating element 11. The electronic apparatus may
have at least one electronic component as the heat generating
element 11. The electronic apparatus 20 is generally composed so
that a housing (or exterior) encloses an electronic circuit board
on which at least one electronic component is mounted. The chemical
heat pump 10 is provided on such electronic apparatus 20 (more
specifically, in the housing thereof). In the present embodiment,
the chemical heat pump 10 may be understood as means for
suppressing temperature rise of the heat generating element 11 (or
cooling the heat generating element).
[0117] The heat generating element 11 may be an electronic
component wherein a part of the energy input thereto is converted
into heat and lost by generating the heat. Examples of the heat
generating element 11 includes: integrated circuits (ICs) such as a
central processing unit (CPU), a power management IC (PMIC), a
power amplifier (PA), a transceiver IC, and a voltage regulator
(VR); light emitting elements such as a light emitting diode (LED),
an incandescent lamp, and a semiconductor laser; a field effect
transistor (FET) and so on, but not limited thereto. In the
electronic apparatus 20, at least one heat generating element may
be present, but generally there may be two or more heat generating
elements.
[0118] The reaction chamber 1 of the chemical heat pump 10
described above is thermally combined to the heat generating
element 11. For example, the portion made of a heat conductive
material of the reaction chamber 1 may be placed in contact
directly or indirectly with the heat generating element 11. Thus,
heat transfer is attained between the heat generating element 11
and the reaction chamber 1. If two or more heat generating elements
are present in the electronic apparatus 20, one or more heat
generating element 11 may be thermally combined with the reaction
chamber 1.
[0119] On the other hand, although this is not essential to the
present embodiment, the condensation/evaporation chamber 3 of the
chemical heat pump 10 may be placed so as to be thermally combined
with any suitable heat conductive member 13 existing in the
electronic apparatus 20. The heat conductive member 13 may be one
having a temperature lower than the temperature of the heat
generating element 11 while the heat generating element 11
generates heat. Examples of the heat conductive member 13 include
the housing of the electronic apparatus, an exterior of a battery
(e.g. lithium ion battery, alkaline battery, nickel hydride
battery), a substrate, a display and so on, but not limited
thereto. For example, the portion made of a heat conductive
material of the condensation/evaporation chamber 3 may be placed in
contact directly or indirectly with the heat conductive member 13.
Thus, heat transfer is attained between the
condensation/evaporation chamber 3 and the heat conductive member
13. One or more heat conductive member 13 may be thermally combined
with the condensation/evaporation chamber 3.
[0120] In the present invention, two members "thermally combined"
with each other mean that they are combined so as to enable heat to
transfer between them. The thermal combination may be realized by
heat conduction through a direct or indirect contact, by thermal
radiation with no contact, or by using a heat medium or a heat
conductive member. When two members are indirectly in contact with
each other in order to be thermally combined, they are preferably
in contact with each other by using an adhesive layer of heat
conductive (e.g. a layer obtained by using an adhesive of which
thermal conductivity is increased by a metal filler or the like), a
member made of a heat conductive material (e.g. a heat transfer
plate made of a metal, a thermal sheet) or the like.
[0121] The electronic apparatus 20 of the present embodiment
configured as described above may be used in the following two
modes.
[0122] First Mode (Heat Storage Process)
[0123] First, when the heat generating element 11 starts to
generate heat by energy input thereto and causes temperature rise
of the heat generating element 11, the heat is transferred to the
reaction chamber 1 which is thermally combined with the heat
generating element 11. Specifically, the heat generated by the heat
generating element 11 is transferred from the outer surface of the
heat generating element 11 to the chemical heat storage material
contained in the reaction chamber 1 through, for example, the
portion made of a heat conductive material of the reaction chamber
1. When the heat is supplied to the reaction chamber in this
manner, the endothermic reaction of the chemical heat storage
material (heat storage) proceeds in the reaction chamber to produce
the condensable component (i.e. a partial pressure of the
condensable component in the reaction chamber is increased). As a
result, an amount of the heat is taken away from the heat
generating element, and thereby the rise in the temperature of the
heat generating element is suppressed (typically, the temperature
of the outer surface of the heat generating element, which shall
apply hereafter).
[0124] The condensable component produced in the reaction chamber
in this way moves from the reaction chamber 1 to the
condensation/evaporation chamber 3 through the communication part 5
in a gas state (vapor). Such movement may occur naturally by
diffusion phenomenon, but is not limited thereto. When the
communication part 5 is provided with a valve, it is possible to
control the movement of the condensable component by opening and
closing the valve.
[0125] In the condensation/evaporation chamber 3, the condensable
component is condensed to generate heat (latent heat). For example,
in the case in which the condensable component is water, water in a
gas state is phase changed into water in a liquid state according
to the following reaction:
1 2 H 2 O ( g ) .fwdarw. 1 2 H 2 O ( l ) + Q 3 ##EQU00002##
[0126] wherein Q.sub.3 is known as 20.9 kJ/mol.
[0127] The temperature in the condensation/evaporation chamber may
rise due to the heat generated. In this case, the pressure in the
condensation/evaporation chamber is preferably made equal to a
saturated vapor pressure of the condensable component beforehand
(at a non-heat generating condition) so that the condensable
component is in a state of vapor-liquid equilibrium (at a
temperature, for example, which is appropriately selected for the
heat conductive member 13 when the heat conductive member 13 is
placed to be thermally combined with the condensation/evaporation
chamber 3), which makes condensation proceed so rapidly.
[0128] Then, although it is not essential to the present
embodiment, in the case of the condensation/evaporation chamber 3
being thermally combined with the heat conductive member 13, the
heat generated in the condensation/evaporation chamber 3 is
transferred to the heat conductive member 13 through, for example,
the portion made of a heat conductive material of the
condensation/evaporation chamber.
[0129] As described above, according to the first mode, it is
possible to suppress the temperature rise of the heat generating
element 11 (or cool the heat generating element) by utilizing the
endothermic reaction (heat storage) of the chemical heat storage
material. Further, in the case of the condensation/evaporation
chamber 3 being thermally combined with a housing of the electronic
apparatus 20 as the heat conductive member 13, by storing heat with
the chemical heat storage material and assuring that an amount of
the heat flowing to the heat conductive member 13 from the
condensation/evaporation chamber 3 is smaller than an amount of the
heat entering into the reaction camber 1 from the heat generating
element 11 (converting a temperature level), it is possible to
retain the temperature of the housing at a relatively low
temperature. Thus, it becomes possible to control the temperature
of the heat generating element 11, and therefore the temperature of
the electronic apparatus 20 as a whole.
[0130] In the case of the condensation/evaporation chamber 3 being
thermally combined with the heat conductive member 13, by reducing
the temperature of the heat conductive member 13, it is also
possible to attain similar effects (mechanism) to those described
above, and it is possible to remove heat from the heat generating
element 11, thus suppress the temperature rise of the heat
generating element 11, and furthermore to reduce its temperature.
In the present embodiment, the heat generating element 11 and the
heat conductive member 13 can be understood as the first member
thermally combined with the reaction chamber and the second member
thermally combined with the condensation/evaporation chamber 3,
respectively. However, the first member and the second member are
not limited thereto, but may be thermally designed by applying any
suitable members.
[0131] Second Mode (Heat Release Process)
[0132] Then, when the temperature of the heat generating element 11
is decreased by, for example, stopping or reducing the energy input
to the heat generating element 11, heat is transferred to the heat
generating element 11 from the reaction chamber 1 which is
thermally combined therewith. Specifically, the heat is transferred
from the system in the reaction chamber 1 to the heat generating
element 11 through, for example, the portion made of a heat
conductive material of the reaction chamber 1. When the heat is
taken away from the system in the reaction chamber 1 in this
manner, the exothermic reaction of the chemical heat storage
material (heat release), which is a reverse reaction to the
endothermic reaction described above, proceeds in the reaction
chamber 1 to consume the condensable component (i.e. the partial
pressure of the condensable component in the reaction chamber is
decreased). As a result, the temperature of the heat generating
element 11 shifts to increase.
[0133] When the condensable component are consumed in the reaction
chamber 1 in this manner, the condensable component moves from the
condensation/evaporation chamber 3 to the reaction chamber 1
through the communication part 5 in a gas state (vapor). Such
movement may also occur naturally by diffusion phenomenon, but is
not limited thereto. When the communication part 5 is provided with
a valve, it is possible to control the movement of the condensable
component by opening and closing the valve.
[0134] In the condensation/evaporation chamber 3, the condensable
component in a liquid phase is evaporated by obtaining heat (latent
heat). The temperature in the condensation/evaporation chamber 3
may be decreased by being deprived of heat.
[0135] Then, although it is not essential to the present
embodiment, in the case of the condensation/evaporation chamber 3
being thermally combined with the heat conductive member 13, heat
is transferred from the heat conductive member 13 to the
condensation/evaporation chamber 3 through, for example, the
portion made of a heat conductive material of the
condensation/evaporation chamber 3. In other words, it is possible
to obtain cold energy from the condensation/evaporation chamber 3
to the heat conductive member 13.
[0136] As described above, according to the second mode, it is
possible to suppress the temperature decrease of the heat
generating element 11 by utilizing the exothermic reaction (heat
release) of the chemical heat storage material. Further, in the
case of the condensation/evaporation chamber 3 being thermally
combined with a housing of the electronic apparatus 20 or an
exterior of a battery as the heat conductive member 13, it is also
possible to decrease the temperature of the housing or the battery
(or cool the housing or the battery). Thus, it becomes possible to
control the temperature of the heat generating element 11, and
therefore the temperature of the electronic apparatus 20 as a
whole.
[0137] In the case of the condensation/evaporation chamber 3 being
thermally combined with the heat conductive member 13, by raising
the temperature of the heat conductive member 13, it is also
possible to attain similar effects (mechanism) to those described
above, and it is possible to increase the temperature of the heat
generating element 11. In the present embodiment, the heat
generating element 11 and the heat conductive member 13 can be
understood as the first member thermally combined with the reaction
chamber and the second member thermally combined with the
condensation/evaporation chamber, respectively. However, the first
member and the second member are not limited thereto, but may be
thermally designed by applying any suitable member. For example, it
is also possible to suppress the temperature rise of the second
member (or cool the second member) by the second mode.
[0138] As can be understood from the above, differently from the
conventional method using a cooling fan for heat dissipation, the
electronic apparatus of the present invention does not require
additional energy input for the purpose of suppressing the
temperature rise of the heat generating element, so that the
electronic apparatus showing superior energy efficiency is
realized.
[0139] Also, differently from the conventional method using a
cooling fan for heat dissipation, the electronic apparatus of the
present invention does not dissipate heat by convection (not
exhaust out by generating gas stream), so that the housing of the
electronic apparatus may be in a sealed condition (closed
system).
[0140] Further, compared with the conventional method using a heat
pipe for heat dissipation, since the electronic apparatus of the
present invention stores heat with the chemical heat storage
material, it is possible to obtain a high capacity of heat storage
and to obtain a high ability of heat dissipation. Further, in the
case of the condensation/evaporation chamber being thermally
combined with the heat conductive member, in the first mode
described above (heat storage process) an amount of the heat
flowing to the heat conductive member from the
condensation/evaporation chamber can be smaller than an amount of
the heat entering into the reaction camber from the heat generating
element (a temperature level can be converted), and in the second
mode descried above (heat release process) cold energy can be
obtained for the heat conductive member. Thus, by using the housing
of the electronic apparatus as the heat conductive member thermally
combined with the condensation/evaporation chamber, it is possible
to retain the temperature of the housing at a relatively low
temperature (for example, the surface temperature of 55.degree. C.
or less) and to reduce the adverse effects due to the temperature
on other element(s) in the housing (e.g. lithium ion battery).
Further, by using the exterior of the battery as the heat
conductive member thermally combined with the
condensation/evaporation chamber, it is possible to extend life of
the battery (e.g. lithium ion battery, which would have a problem
of the lowered battery capacity due to a high environmental
temperature for use). Further, by using the substrate as the heat
conductive member thermally combined with the
condensation/evaporation chamber, it is possible to prevent a
reliability of the other electronic element(s) mounted on the
substrate from impairing.
[0141] In addition, according to the electronic apparatus of the
present invention, the first member thermally combined with the
reaction chamber and the second member thermally combined with the
condensation/evaporation chamber can be thermally designed by
applying any suitable members, so that it becomes possible to
provide the electronic element(s) with a thermally optimal layout
depending on the detailed specifications of the electronic
apparatus.
[0142] In the above, the electronic apparatus in one embodiment of
the present invention has described in detail, but the electronic
apparatus of the present invention is not limited to such
embodiment and may be made with various modifications based on the
basic concept of the present invention.
[0143] For example, the number of the chemical heat pump(s)
installed in the electronic apparatus, the number of the chemical
heat pump(s) used for one heat generating element, the number, and
the arrangement and so on of the reaction chamber(s), the
condensation/evaporation chamber(s) and the communication part(s)
present in one chemical heat pump can be appropriately
selected.
[0144] Also, for example, the condensation/evaporation chamber may
be surrounded by an ambient atmosphere in the housing (e.g.
so-called air insulation). Alternatively, the
condensation/evaporation chamber does not have the portion made of
a heat conductive material and is composed of a material showing a
low heat conductivity or heat insulation. Further, the
condensation/evaporation chamber itself may be eliminated, and also
in this case, it is possible to some extent to suppress the
temperature rise of the heat generating element by the endothermic
reaction of the chemical heat storage material.
[0145] That is, as shown in FIG. 2, the electronic apparatus 21 in
other embodiment of the present invention includes essentially the
heat generating element 11 and at least one reaction chamber 1
containing a chemical heat storage material (which may form a solid
phase 2a). In this case, heat generated by the heat generating
element 11 is transferred from the outer surface of the heat
generating element 11 to the chemical heat storage material
contained in the at least one reaction chamber 1, and the chemical
heat storage material absorbs the heat by a reaction, and thereby
it is possible to suppress the temperature rise of the heat
generating element 11. As long as the heat generating element 11 is
thermally combined with the reaction chamber 1, the heat generating
element 11 may be placed in any manner.
[0146] There may be present two reaction chambers in the electronic
apparatus in such other embodiment. More specifically, as shown in
FIG. 3A, in the electronic apparatus 22, there may be present the
first reaction chamber 1a containing the first chemical heat
storage material and the second reaction chamber 1b containing the
second chemical heat storage material. The first chemical heat
storage material and the second chemical heat storage material may
absorb or produce heat by any reactions involving the same
component (component functioning as a working medium, for example,
a condensable component, but not limited thereto, and may be any
component which is able to exists in a gas state). The first
chemical heat storage material and the second chemical heat storage
material may have vapor-liquid equilibrium states which are
different from each other. The first chemical heat storage material
and the second chemical heat storage material may be selected from
those exemplified for the chemical heat storage material in the
above, and for example, one of the first chemical heat storage
material and the second chemical heat storage material may be
calcium sulfate hemihydrate, and the other may be calcium chloride
hydrate, and water as the same component described above is
involved in their reversible reactions for absorbing and producing
heat, but not limited thereto. The first reaction chamber 1a and
the second reaction chamber 1b communicate with each other by a
communication part 5a therebetween to allow the component (working
medium) to move, and heat generated by the heat generating element
(not shown) may be transferred to either the first chemical heat
storage material in the first reaction chamber 1a or the second
chemical storage material in the second reaction chamber 1b. As
long as the heat generated by the heat generating element (not
shown) may be transferred to either the first reaction chamber 1a
or the second reaction chamber 1b selectively or switchably, an
arrangement of the heat generating element, the first reaction
chamber 1a and the second reaction chamber 1b is not particularly
limited.
[0147] Further, as an electronic apparatus 23 shown in FIG. 3B, it
may further include a condensation/evaporation chamber 3a for
condensing or evaporating the movable component described above,
and the condensation/evaporation chamber 3a communicates with the
communication part 5a between the first reaction chamber 1a and the
second reaction chamber 1b through a communication part 5b. This
arrangement of the condensation/evaporation chamber 3a is a
parallel arrangement with respect to two reaction chambers 1a and
1b.
[0148] Alternatively, as an electronic apparatus 24 shown in FIG.
3C, it may further include a condensation/evaporation chamber 3b
for condensing or evaporating the movable component described
above, and the condensation/evaporation chamber 3b communicates
with either the first reaction chamber 1a or the second reaction
chamber 1b (with the second reaction chamber 1b in FIG. 3C) through
another communication part 5c. This arrangement of the
condensation/evaporation chamber 3b is a series arrangement with
respect to two reaction chambers 1a and 1b.
[0149] In examples of FIGS. 3B and 3C, the movable component
corresponds to the condensable component (i.e. a component which is
able to change its phase between a gaseous state (gas phase) and a
liquid state (liquid phase)), but are not limited thereto. For
example, the movable component may be a component which is able to
change its phase between a gaseous state (gas phase) and a solid
state (solid phase), and in this case the condensation/evaporation
chambers 3a and 3b are understood as a sublimation chamber.
[0150] FIGS. 3A to 3C are intended to exemplary illustrate other
embodiment of the present invention, the number of the reaction
chambers, and the number of the condensation/evaporation chamber(s)
and the sublimation chamber(s) if present, and an arrangement
thereof can be appropriately selected.
[0151] As to the electronic apparatus in such other embodiment of
the present invention, similar descriptions to those in the
embodiment described above are also applicable unless otherwise
noted.
[0152] For example, the electronic apparatus of other embodiment
shown in FIGS. 3A to 3C preferably has any of the following
features, either alone or in combination of any two or more:
[0153] (i') any of the communication parts 5a, 5b, 5c connecting
between the reaction chamber 1a and the second reaction chamber 1b
and the condensation/evaporation chamber 3a or 3b (preferably the
communication parts 5b, 5c at the side of the
condensation/evaporation chamber) is provided with a filter
allowing gas to path through but not substantially allowing solid
and liquid to path through;
[0154] (ii') the first chemical heat storage material is molded or
packed in the first reaction chamber 1a, the minimum
cross-sectional dimension of the first chemical heat storage
material which is molded or packed being larger than the minimum
cross-sectional dimension of the communication part 5a; and/or the
second chemical heat storage material is molded or packed in the
second reaction chamber 1b, the minimum cross-sectional dimension
of the second chemical heat storage material which is molded or
packed being larger than the minimum cross-sectional dimension of
the communication part 5a (and preferably another communication
part 5c, if present);
[0155] (iii') the condensation/evaporation chambers 3a, 3b contain
a material capable of trapping liquid, or at least a portion of an
inner surface of the condensation/evaporation chambers 3a, 3b is
made of the material capable of trapping liquid.
[0156] As to these features, similar descriptions to those in the
embodiment described above with reference to FIG. 1 and FIGS. 12A
to 12D are also applicable, and the similar effects can be
obtained.
[0157] In the above, the electronic apparatus in some embodiments
of the present invention has described, but all of these may be
made with further modifications.
[0158] That is, the electronic apparatuses in the embodiments
described above are all uses the chemical heat storage material,
but instead of this, other heat storage material which is able to
generate a phase changeable component in association with an
endothermic phenomenon may be used. In this case, the phase
changeable component is a working medium of the device, this
component can move from the reaction chamber in a gaseous state,
and the condensation/evaporation chamber or the sublimation chamber
described above is understood as a chamber where this component
changes its phase (i.e. phase change chamber), which may function
as a condensation/evaporation chamber and/or a sublimation
chamber.
[0159] Such other heat storage material may be appropriately
selected (for example, so as to show the endothermic phenomenon by
heat generated by the heat generating element) depending on
applications of the electronic apparatus of the present invention.
Similarly to the chemical heat storage material, such other heat
storage material is preferably one showing the endothermic
phenomenon at a temperature such as 30 to 200.degree. C., and more
preferably one showing the endothermic reaction at a temperature of
40.degree. C. or more, particularly 50.degree. C. or more, and of
150.degree. C. or less, particularly 120.degree. C. or less.
[0160] As said other heat storage material which may be used in the
present invention, for example, at least one heat storage material
selected form the group consisting of, for example, zeolite, silica
gel, mesoporous silica and activated carbon may be used
(hereinafter, these are simply referred to as "zeolite, etc."). All
of them are able to reversibly adsorb and desorb, for example,
water (or hydration or dehydration, which shall apply hereafter),
and show an endothermic phenomenon on desorption of water:
Z.xH.sub.2O(s)+Q.sub.4.fwdarw.Z(s)+xH.sub.2O(g)
[0161] wherein Z represents the composition of the zeolite etc.,
and x may be a variously changeable value depending on the
composition. Although it depends on the specific composition,
Q.sub.4 is about 30 to 80 kJ/mol in the case of zeolite. This
desorption of water, depending on the various conditions, but may
proceed at, for example, about 50 to 150.degree. C. for zeolite,
about 5 to 150.degree. C. for silica gel, about 5 to 150.degree. C.
for mesoporous silica, and about 5 to 150.degree. C. with activated
carbon.
[0162] Zeolite means crystalline, hydrated aluminosilicates having
a basic skeleton of so-called zeolite structure, that is, a
three-dimensional network structure composed of SiO.sub.4
tetrahedra and AlO.sub.4 tetrahedra which are linked by sharing
apical oxygen atoms. In general, zeolite can be represented by the
following general formula:
(M.sup.1,M.sup.2.sub.1/2).sub.m(Al.sub.mSi.sub.nO.sub.2(m+n)).xH.sub.2O(-
n.gtoreq.m)
[0163] wherein M.sup.1 is a monovalent cation such as Li.sup.+,
Na.sup.+, and K.sup.+, M.sup.2 is a divalent cation such as
Ca.sup.2+, Mg.sup.2+, and Ba.sup.2+.
[0164] Among them, zeolites which may be suitably used in the
present invention are A-type zeolite (LTA), X-type zeolite (FAU),
Y-type zeolite (FAU), beta-type zeolite (BEA), ALPO-5 (AFI), and so
on.
[0165] Silica gel is a three-dimensional structure of colloidal
silica, of which porous material properties can be controlled in a
wide range, e.g. pore size from several nanometers to several tens
of nanometers and specific surface area from 5 to 1000 m.sup.2/g.
In addition, the surface of primary particles of silica gel is
covered by silanol, so that it selectively adsorbs polar molecules
(e.g. water) under the influence of silanol.
[0166] Mesoporous silica is a substance of silicon dioxide having
uniform and regular pores, of which pore size is about 2 to 10
nm.
[0167] Activated carbon is means "porous, carbonaceous matter
having pores" which have a large specific surface area and
adsorption capacity. Its basic skeleton is a planar structure of a
two-dimensional lattice of carbon atoms connected each other by an
angle of 120.degree.. As such two-dimensional lattices are stacked
irregularly to form a crystal lattice, and the crystal lattices are
linked randomly to form active carbon. Voids between the crystal
lattices are pores of the activated carbon, and water is adsorbed
in the pores.
[0168] In advance of the preparation of the electronic apparatus of
the present invention, the zeolite, etc. are preferably made
adsorbed water sufficiently.
[0169] When the zeolite etc. are used as said other heat storage
material in the electronic apparatus of the present invention,
water as the condensable component is the working medium, and
therefore it is possible to attain similar effects by similar
mechanism to those in the above described embodiments using the
chemical heat storage material (which produces water as the
condensable component and uses it as the working medium).
[0170] An electronic apparatus of the present invention can be
suitably used as mobile electronic devices such as smartphones,
cellular phones, tablet devices, laptop computers, portable game
machines, portable music players, digital cameras, and so on.
EXAMPLES
CHP-Equipped Examples
[0171] Chemical heat pump (CHP) equipped examples which apply
various elements/members as the first member/heat generating
element 11 and the second member/heat conductive member 13 in an
electronic apparatus of the present invention will be described
below in detail with reference to the accompanying drawings, but
the present invention is not limited thereto.
[0172] (CHP-Equipped Example 1)
[0173] Referring to FIG. 4, in this CHP-equipped example, the
electronic apparatus is a laptop PC (personal computer) 20a, and
the heat generating element is a CPU 11a. A chemical heat pump
includes a reaction chamber 1, a condensation/evaporation chamber
3, and a communication part 5 for communicating therebetween. The
reaction chamber 1 is thermally combined with the CPU 11a. For
example, by using an adhesive of which thermal conductivity is
increased with a metal filler, the reaction chamber 1 may be
adhered to the CPU 11a, but is not limited thereto. The
condensation/evaporation chamber 3 is not thermally combined with a
lithium ion battery 13a and a housing 13b and is thermally
insulated by air. The condensation/evaporation chamber 3 is
preferably thermally insulated from the CPU 11a (the heat
generating element).
[0174] In this CHP-equipped example, when the CPU 11a is operated
and generates heat to reach a relatively high temperature (which
depends on the chemical heat storage material to be used), an
endothermic reaction of the chemical heat storage material in the
reaction chamber 1 proceeds by drawing heat from the CPU 11a (the
condensable component generated during the reaction may be
condensed in the condensation/evaporation chamber 3), thereby
reducing the temperature rise of the CPU 11a, preferably to
stabilize the temperature of the CPU 11a, and thus to maintain the
temperature of the CPU 11a not exceeding the upper temperature
limit. Thereafter, the operation of the CPU 11a is changed to a
lower level or stopped and the temperature of the CPU 11a is
decreased to a relatively lower temperature, an exothermic reaction
of the chemical heat storage material in the reaction chamber 1
proceeds to provide heat to the CPU 11a (at this time, the
condensable component may be evaporated in the
condensation/evaporation chamber 3), and thus the temperature of
the CPU 11a may rise slightly. That is, the chemical heat pump
draws heat from the CPU 11a during the high temperature operation
of the CPU 11a, and provides heat to the CPU 11a during the low
temperature operation.
[0175] (CHP-Equipped Example 2)
[0176] Referring to FIG. 5, in this CHP-equipped example, the
electronic apparatus is a laptop PC 20a, and the heat generating
element is a CPU 11a. A chemical heat pump 10 includes a reaction
chamber 1, a condensation/evaporation chamber 3, and a
communication part 5 for communicating therebetween. The reaction
chamber 1 is thermally combined with the CPU 11a. The
condensation/evaporation chamber 3 is thermally combined with a
housing 13b. For example, by using an adhesive of which thermal
conductivity is increased with a metal filler, the reaction chamber
1 and the condensation/evaporation chamber 3 may be adhered to the
CPU 11a and the housing 13b respectively, but are not limited
thereto.
[0177] In this CHP-equipped example, when the CPU 11a is operated
and generates heat to reach a relatively high temperature (which
depends on the chemical heat storage material to be used), an
endothermic reaction of the chemical heat storage material in the
reaction chamber 1 proceeds by drawing heat from the CPU 11a, and
the condensable component generated by the endothermic reaction is
condensed in the condensation/evaporation chamber 3 to provide heat
to the housing 13b, thereby reducing the temperature rise of the
CPU 11a, preferably to stabilize the temperature of the CPU 11a,
and thus to maintain the temperature of the CPU 11a not exceeding
the upper temperature limit (e.g. 120.degree. C. or less).
Thereafter, the operation of the CPU 11a is changed to a lower
level or stopped and the temperature of the CPU 11a is decreased to
a relatively lower temperature, an exothermic reaction of the
chemical heat storage material in the reaction chamber 1 proceeds
and the condensable component in the condensation/evaporation
chamber 3 evaporates by drawing heat from the housing 13b, and thus
the temperature of the CPU 11a rises slightly and the temperature
of the housing 13b is decreased and can be retained at a relatively
lower temperature (e.g. 55.degree. C. or less). That is, the
chemical heat pump 10 draws heat from the CPU 11a and transfer heat
to the housing 13b during the high temperature operation of the CPU
11a, and provides heat to the CPU 11a and draws heat from (cools)
the housing 13b during the low temperature operation.
[0178] (CHP-Equipped Example 3)
[0179] Referring to FIG. 6, in this CHP-equipped example, the
electronic apparatus is a smartphone 20b, and the heat generating
element is a power management IC 11b. A chemical heat pump 10
includes a reaction chamber 1, a condensation/evaporation chamber
3, and a communication part 5 for communicating therebetween. The
reaction chamber 1 is thermally combined with the power management
IC 11b. The condensation/evaporation chamber 3 is thermally
combined with a lithium ion battery 13a. For example, by using an
adhesive of which thermal conductivity is increased with a metal
filler, the reaction chamber 1 and the condensation/evaporation
chamber 3 may be adhered to the power management IC 11b and the
lithium ion battery 13a respectively, but are not limited
thereto.
[0180] In this CHP-equipped example, when the power management IC
11b is operated and generates heat to reach a relatively high
temperature (which depends on the chemical heat storage material to
be used), an endothermic reaction of the chemical heat storage
material in the reaction chamber 1 proceeds by drawing heat from
the power management IC 11b, and the condensable component
generated by the endothermic reaction is condensed in the
condensation/evaporation chamber 3 to provide heat to the lithium
ion battery 13a, thereby reducing the temperature rise of the power
management IC 11b, preferably to stabilize the temperature of the
power management IC 11b, and thus to maintain the temperature of
the power management IC 11b not exceeding the upper temperature
limit (e.g. 85.degree. C. or less). Thereafter, the operation of
the power management IC 11b is changed to a lower level or stopped
and the temperature of the power management IC 11b is decreased to
a relatively lower temperature, an exothermic reaction of the
chemical heat storage material in the reaction chamber 1 proceeds
and the condensable component in the condensation/evaporation
chamber 3 evaporates by drawing heat from the lithium ion battery
13a, and thus the temperature of the power management IC 11b rises
slightly and the temperature of the lithium ion battery 13a is
decreased and can be retained at/within a temperature which does
not cause the problem of a shorter lifetime of lithium ion battery
13a (e.g. 40.degree. C. or less). That is, the chemical heat pump
10 draws heat from the power management IC 11b and transfer heat to
the lithium ion battery 13a during the high temperature operation
of the power management IC 11b, and provides heat to the power
management IC 11b and draws heat from (cools) the lithium ion
battery 13a during the low temperature operation.
[0181] (CHP-Equipped Example 4)
[0182] Referring to FIG. 7, in this CHP-equipped example, the
electronic apparatus is a smartphone 20b, and the heat generating
elements are two power amplifiers 11c and 11c'. The first chemical
heat pump 10 includes a reaction chamber 1, a
condensation/evaporation chamber 3, and a communication part 5 for
communicating therebetween. The second chemical heat pump 10'
includes a reaction chamber 1', a condensation/evaporation chamber
3', and a communication part 5' for communicating therebetween. The
reaction chamber 1 is thermally combined with the power amplifier
11c. The reaction chamber 1' is thermally combined with the power
amplifier 11c'. The condensation/evaporation chambers 3 and 3' are
thermally combined with a housing 13b. For example, by using an
adhesive of which thermal conductivity is increased with a metal
filler, the reaction chamber 1 and the condensation/evaporation
chamber 3 may be adhered to the power amplifier 11c and the housing
13b respectively, and the reaction chamber 1' and the
condensation/evaporation chamber 3' may be adhered to the power
amplifier 11c' and the housing 13b respectively, but are not
limited thereto.
[0183] In this CHP-equipped example, when the power amplifier 11c
is operated during the use of Band 1 and generates heat to reach a
relatively high temperature (which depends on the chemical heat
storage material to be used), an endothermic reaction of the
chemical heat storage material in the reaction chamber 1 proceeds
by drawing heat from the power amplifier 11c, and the condensable
component generated by the endothermic reaction is condensed in the
condensation/evaporation chamber 3 to provide heat to the housing
13b, thereby reducing the temperature rise of the power amplifier
11c, preferably to stabilize the temperature of the power amplifier
11c, and thus to maintain the temperature of the power amplifier
11c not exceeding the upper temperature limit (e.g. 85.degree. C.
or less). Thereafter, switching from Band 1 to Band 2, the
operation of the power amplifier 11 is stopped and the power
amplifier 11c' is made operated. Then, the power amplifier 11c' is
operated and generates heat to reach a relatively high temperature
(which depends on the chemical heat storage material to be used),
an endothermic reaction of the chemical heat storage material in
the reaction chamber 1' proceeds by drawing heat from the power
amplifier 11c', and the condensable component generated by the
endothermic reaction is condensed in the condensation/evaporation
chamber 3' to provide heat to the housing 13b, thereby reducing the
temperature rise of the power amplifier 11c', preferably to
stabilize the temperature of the power amplifier 11c', and thus to
maintain the temperature of the power amplifier 11c' not exceeding
the upper temperature limit (e.g. 85.degree. C. or less). On the
other hand, the temperature of the power amplifier 11c is decreased
to a relatively lower temperature, and an exothermic reaction of
the chemical heat storage material in the reaction chamber 1
proceeds and the condensable component in the
condensation/evaporation chamber 3 evaporates by drawing heat from
the housing 13b, and thus the temperature of the power amplifier
11c rises slightly and the temperature of the housing 13b is
decreased. Therefore, the housing 13b can be retained at a
relatively lower temperature (e.g. 55.degree. C. or less). That is,
by the switchable use between Band 1 and Band 2, the chemical heat
pumps 10 and 10' draw heat from the power amplifier 11c or 11c' at
the higher temperature operation and transfer heat to the power
amplifier 11c or 11c' at the stopped operation, and thereby it
becomes possible to control the heat transfer to and from the
housing 13b.
[0184] Simulations
[0185] Next, simulations of heat balance were conducted based on
some models.
[0186] (Simulation Model 1)
[0187] Based on a model representing the structure of an existing
smartphone, firstly, validity of an analytical method used for
simulations (including various conditions) was verified in the case
of CPU heat generation amount of 1.8 W (which corresponds to the
actually measured amount of generated heat), and then according to
this analytical method, simulation was conducted for the case of
CPU heat generation amount of 7 W as a comparative example.
[0188] As shown in FIG. 8, this simulation model assumes an
electronic apparatus model 30 wherein an electronic circuit board
22 mounting a CPU 21a and a power management IC (PMIC) 21b
respectively on its upper and lower surfaces, a battery 24, and a
camera unit 25 are housed in a space between a chassis (upper heat
conductive member) 23a and a battery cover (lower heat conductive
member) 23b, and a display 26 is placed on the upper surface of the
chassis 23a. The camera unit 25 is in contact with the electronic
circuit board 22, the chassis 23a and the battery cover 23b. The
battery 24 is in contact with the chassis 23a and the battery cover
23b. The electronic circuit board 22 is not contact with the
battery 24, but in contact with the battery cover 23b (contacting
part is not shown). The chassis 23a is in contact with the display
26, and the display 26 is exposed to an ambient atmosphere (air)
29. A portion of the battery cover 23b is in contact with a human
body 28, and the rest thereof is exposed to the ambient atmosphere
(air) 29. The imaginary routes for allowing heat to move in and out
in this electronic apparatus model 30 are shown by double arrows in
FIG. 8.
[0189] The dimensions and the heat generation amount for each of
the above described members in the electronic apparatus model 30
were set as shown in Table 1 below (in Table 1, the symbol "-"
means that the heat generation amount is zero). Among these
members, the CPU 21a and the PMIC 21b are heat generating elements,
the camera unit 25 and the battery 24 are also heat generating
elements but their amounts of heat generation is very small
compared to the CPU 21a and the PMIC 21b.
TABLE-US-00001 TABLE 1 Dimensions Heat Member (Reference signs in
Length Width Height generation the Drawings) (mm) (mm) (mm) amount
(W) Display (26) 82.2 54.8 2.14 -- Chassis (23a) 115.7 58.5 1.5 --
Electronic circuit board (22) 96.5 41.3 0.8 -- Camera unit (25) 8.9
9.2 7.2 0.2 Battery (24) 81.4 31.5 4.3 0.2 Battery cover (23b) 115
58 1.5 -- CPU (21a) 16.5 14 0.8 1.8 or 7 PMIC (21b) 7.4 5.8 0.5
0.8
[0190] With respect to these members, values of physical properties
such as density, specific heat, thermal conductivity, etc. were
appropriately set to correspond to each of members used in an
existing smartphone, and mc value (a product of specific heat and
mass) was calculated for them and used. The specific heat and the
density were assumed to be constant regardless of the
temperature.
[0191] Initial and boundary conditions in the simulation were as
follows.
Initial Conditions:
[0192] A temperature of the ambient atmosphere (air) 29 was
constant at a temperature of 25.degree. C.
[0193] All of the members were at a temperature of 25.degree.
C.
Boundary Condition:
[0194] The CPU 21a, the PMIC 21b, the camera unit 25, and the
battery 24 were intended to start heat generation at t=0 (the start
time of heat generation was set at t=0).
[0195] The human body 28 was constant at a temperature of
36.degree. C., and at t=0, one third of the exposed surface of the
battery cover 23b came in contact (heat transfer) with the human
body 28, and the remaining two third was exposed to the ambient
atmosphere (air) 29.
[0196] Heat transfer between the display 26, the battery cover 23b
and the ambient atmosphere (air) 29 was obtained by convection heat
transfer and radiation heat transfer.
[0197] Other heat transfer was obtained by conduction heat
transfer, unless otherwise noted.
[0198] In the Case of CPU Heat Generation Amount of 1.8 W
(Validation of the Analytical Method)
[0199] The amount of heat generation by a CPU used in an existing
smartphone was measured as about 1.8 W.
[0200] Therefore, first, setting the heat generation amount of the
CPU 21a in the electronic apparatus model 30 at 1.8 W, simulation
of heat balance was conducted by applying the analytical method
comprising the various conditions/assumptions described above. As
the results of this simulation, there were shown that: the
temperature of the CPU 21a increased to about 50.degree. C. at
t=about 100 seconds, reached to about 60.degree. C. at t=about
1,000 seconds, and became in a quasi-steady state; and the
temperature of the battery cover 23b increased to about 40.degree.
C. at t=about 1,000 seconds and became in a quasi-steady state.
[0201] On the other hand, the existing smartphone was used under
the similar conditions (in the ambient atmosphere of 25.degree. C.,
and one third of the exposed surface of the battery cover 23b was
made contact with the human body having a body temperature of about
36.degree. C.), and the temperatures of the CPU and the battery
cover, etc. were actually measured. The measured temperatures of
the CPU and the battery cover in the quasi-steady states were
62.degree. C. and 39.degree. C. respectively, and they were almost
same as the simulated values described in the above.
[0202] Therefore, the analytical method applied in this simulation
was proved to be appropriate.
In the Case of CPU Heat Generation Amount of 7 W
Comparative Example
[0203] Setting the heat generation amount of the CPU 21a of the
electronic apparatus model 30 as unknown value, and the simulation
was conducted by applying the analytical method comprising the
various conditions/assumptions described above, resulting in that
the heat generation amount of the CPU 21a at a point showing the
temperature of the CPU 21a at 130.degree. C. in quasi-steady state
was calculated to be 7 W. The condition for a heat generation
amount of CPU at 7 W is too severe to be supposed under normal
conditions for use of CPUs.
[0204] Then, assuming the heat generation amount of the CPU 21a in
the electronic apparatus model 30 at 7 W, simulation of heat
balance was conducted by applying the analytical method comprising
the various conditions/assumptions described above. As the results
of this simulation, there were shown that: the temperature of the
CPU 21a increased to about 100.degree. C. at t=about 100 seconds,
reached to about 120.degree. C. at t=about 400 seconds, and became
in a quasi-steady state of about 130.degree. C. at t=about 1,000
seconds; and the temperature of the battery cover 23b increased to
about 53.degree. C. at t=about 1,000 seconds.
[0205] (Simulation Model 2)
[0206] With respect to one model of an example of the electronic
apparatus of the present invention, simulation was conducted. This
model represents the structure of an existing smartphone similarly
to Simulation model 1 in the above, but differs significantly in
that this model is intended to be equipped with one chemical heat
pump. According to the analytical method as in Simulation model 1,
this simulation was conducted for the case of CPU heat generation
amount of 7 W.
[0207] As shown in FIG. 9, this simulation model assumes an
electronic apparatus model 31 which is similar to the electronic
apparatus model 30 of FIG. 8, with the exception that one chemical
heat pump 10 is added so that a reaction chamber 1 and a
condensation/evaporation chamber 3 are attached to the CPU 21a and
the chassis (upper heat conductive member) 23a respectively, and
the chassis 23a is distant from the battery 24 and the camera unit
25. The imaginary routes for allowing heat to move in and out in
this electronic apparatus model 31 are shown by double arrows in
FIG. 9. It is noted in the electronic apparatus model 31 that the
reaction chamber 1 is switchable between a state where it is
thermally isolated from other members and a state where it is
thermally combined with the CPU 21a.
[0208] With respect to each of the members in the electronic
apparatus model 31 other than the chemical heat pump 10, the
dimensions and the heat generation amount (the CPU heat generation
amount was 7 W only), the values of physical properties such as
density, specific heat, thermal conductivity, etc., the mc value,
the initial and boundary conditions were similarly set to those in
Simulation model 1 described above.
[0209] With respect to the chemical heat pump 10, it is set and
assumed as follows.
[0210] The reaction chamber 1 is composed of a container (outer
dimensions of 40 mm.times.40 mm.times.2.5 mm, wall thickness of
0.25 mm) made of SUS 304 and filled with 5.23 g of calcium sulfate.
The condensation/evaporation chamber 3 is composed of a container
(outer dimensions of 15 mm.times.15 mm.times.1.5 mm, wall thickness
of 0.25 mm) made od SUS 316 and filled with 0.346 g of distilled
water. With respect to the reaction chamber 1 and the
condensation/evaporation chamber 3, values of physical properties
such as density, specific heat, thermal conductivity, etc. were
appropriately set corresponding to each of the materials, and mc
value (a product of specific heat and mass) was calculated for them
and used. The specific heat and the density were assumed to be
constant regardless of the temperature.
[0211] The thermal contact resistances between the reaction chamber
1 and the CPU 21a, and between the condensation/evaporation chamber
3 and the chassis 23a are disregarded.
[0212] With respect to the communication part 5 communicating
between the reaction chamber 1 and the condensation/evaporation
chamber 3, heat transfer between them is disregarded.
[0213] For an endothermic reaction of calcium sulfate hemihydrate
and an exothermic reaction of calcium sulfate, the known chemical
reaction rate equations are applied (Chemical Engineering
Proceedings (Kagaku Kogaku Ronbun-shu), Vol. 35, No. 4, pp.
390-395, 2009).
[0214] The calcium sulfate hemihydrate/calcium sulfate is assumed
to be in the form of spherical particles having an average particle
diameter of 0.85 mm, and expansion and contraction of the particles
are disregarded.
[0215] With respect to water vapor, translational diffusion
resistance and the like are disregarded, the temperature in the
reaction chamber and the temperature in the
condensation/evaporation chamber correspond to the temperatures of
the respective chambers, a pressure in the condensation/evaporation
chamber corresponds to a pressure of saturated water vapor at that
temperature, and a pressure in the reaction chamber corresponds to
the pressure in the condensation/evaporation chamber communicated
therewith.
In the Case of CPU Heat Generation Amount of 7 W
Example 1
[0216] Assuming the heat generation amount of the CPU 21a in the
electronic apparatus model 31 at 7 W, simulation of heat balance
was conducted by applying the analytical method comprising the
various conditions/assumptions described above. In this simulation,
the chemical heat pump 10 was intended to be operated at heat
release process and then at heat storage process. Change in the
temperatures of the CPU and the reaction chamber with the passage
of time in this simulation is shown in a graph and a table of FIG.
10B. Specifically, it is explained as follows.
[0217] First, based on the initial conditions (t=0), simulation was
conducted by assuming the heat generation amount of the CPU 21a at
7 W and letting the exothermic reaction proceed in the reaction
chamber 1 at adiabatic state (thermally disconnect from the CPU
21a) of the chemical heat pump 10 until the temperature of the CPU
21a reached to 120.degree. C. (shown with the number (1) in FIG.
10A), and then staring heat exchange (heat transfer) by thermally
combining the reaction chamber 1 with the CPU 21a until the
temperature of the CPU 21a reached to 120.degree. C. again. As the
results of this simulation, the followings were shown. The
temperature of the CPU 21a reached to 120.degree. C. at t=about 230
seconds, and during this, calcium sulfate in the reaction chamber 1
reacted with vapor to generate heat at the level of 1.7 W on
average while water in the condensation/evaporation chamber 3
evaporated to absorb heat at the level of 2.1 W as the latent heat,
and the temperature of the reaction chamber 1 increased to
70.degree. C. at t=about 230 seconds (shown with the number (2) in
FIGS. 10A and 10B). Then, by thermally combining the CPU 21a
(120.degree. C.) with the reaction chamber 1 (70.degree. C.) at
t=about 230 seconds, the temperature of the CPU 21a was reduced to
85.degree. C. at t=about 245 seconds (shown with the number (3) in
FIGS. 10A and 10B). Since then, calcium sulfate in the reaction
chamber 1 continued to react with vapor to generate heat at the
level of 1.7 W on average while water in the
condensation/evaporation chamber 3 continued to evaporate to absorb
heat at the level of 2.1 W as the latent heat, and the temperature
of the reaction chamber 1 became 101.degree. C. at t=about 360
seconds (shown with the number (4) in FIGS. 10A and 10B), and the
reaction equilibrium pressure reached the saturated vapor pressure
at the temperature 16.degree. C. of the condensation/evaporation
chamber, and thereby the endothermic reaction in the reaction
chamber 1 was completed (reaction rate of about 97%). Then, the
temperatures of the CPU 21a and the reaction chamber 1 (its inside
and container) reached to about 120.degree. C. at t=590 seconds
(shown with the number (5) in FIGS. 10A and 10B). During this,
water in the condensation/evaporation chamber 3 continued to
evaporate to absorb heat at the level of 2.1 W as the latent heat,
and the temperatures of the condensation/evaporation chamber 3 (its
inside and container), the chassis 23a, and the display 26 were
decreased to about 17.degree. C. at t=about 590 seconds. Thus, the
chemical heat pump operated at the heat release process during t=0
to 360 seconds (reaction rate of about 97%), and was able to make
the temperature of the CPU 21a at 120.degree. C. or less during t=0
to 590 seconds.
[0218] Subsequently (subsequently to the time point of t=590
seconds), simulation was conducted by assuming the heat generation
amount of the CPU 21a at 7 W and keeping thermal combination of the
reaction chamber 1 with the CPU 21a until calcium sulfate
hemihydrate in the reaction chamber 1 at 120.degree. C. generated
water vapor by absorbing heat to reach the reaction rate of 90%. As
the results of this simulation, the followings were shown. In the
reaction chamber 1, calcium sulfate hemihydrate absorbed heat at
the level of 1.3 W on average to emit water vapor continuously
(heat storage), and during t=590 to 1,040 seconds (450 seconds
after the start of absorbing heat) (shown with the number (6) in
FIG. 10A) the temperatures of the CPU 21a and the reaction chamber
1 (its container and inside) were maintained at about 120.degree.
C. The water vapor generated during this time moved to the
condensation/evaporation chamber 3 and emitted heat at the level of
1.6 W as the latent heat on changing into liquid water, and the
temperatures of the condensation/evaporation chamber 3 (its
container and inside), the chassis 23a, and the display 26
increased to about 28.degree. C. at t=1,040 seconds. In addition,
the temperature of the battery cover 23b was increased to about
55.degree. C. at t=1,040 seconds. Thus, the chemical heat pump 10
operated at the heat storage process during t=590 to 1,040 seconds
(reaction rate of about 90%) and was able retain the temperature of
the CPU 21a at about 120.degree. C.
[0219] Therefore, according to this simulation, it was found that
by equipment of the chemical heat pump 10, even in the case where
the CPU heat generation amount is extremely large as 7 W, the CPU
was kept not to exceed 120.degree. C. for the time duration of
approximately 1,040 seconds from the start of heat generation by
the CPU.
[0220] (Simulation Model 3)
[0221] With respect to another model of an example of the
electronic apparatus of the present invention, simulation was
conducted. This model represents the structure of an existing
smartphone similarly to Simulation model 1 in the above, but
differs significantly in that this model is intended to be equipped
with two chemical heat pumps. According to the analytical method as
in Simulation model 1, this simulation was conducted for the case
of CPU heat generation amount of 7 W.
[0222] As shown in FIG. 11, this simulation model assumes an
electronic apparatus model 32 which is similar to the electronic
apparatus model 30 of FIG. 8, with the exception that two chemical
heat pumps 10 and 10' are added so that a reaction chamber 1 and a
reaction chamber 1' are attached to the CPU 21a and the battery
cover (lower heat conductive member) 23b respectively, and
condensation/evaporation chambers 3 and 3' are attached to each
other. The imaginary routes for allowing heat to move in and out in
this electronic apparatus model 32 are shown by double arrows in
FIG. 11.
[0223] With respect to each of the members in the electronic
apparatus model 32 other than the chemical heat pumps 10 and 10',
the dimensions and the heat generation amount (the CPU heat
generation amount was 7 W only), the values of physical properties
such as density, specific heat, thermal conductivity, etc., the mc
value, the initial and boundary conditions were similarly set to
those in Simulation model 1 described above.
[0224] With respect to the chemical heat pumps 10 and 10', these
are set and assumed as follows, and similar settings and
assumptions to those described above with respect to the chemical
heat pump 10 in Simulation model 2 shall apply unless otherwise
noted. (However, the chemical material charged into the reaction
chamber 1 is in the form of calcium sulfate hemihydrate (5.235 g in
calcium sulfate equivalent), and the chemical material charged into
the reaction chamber 1' is in the form of calcium sulfate (5.235
g).)
[0225] The thermal contact resistances between the reaction chamber
1 and the CPU 21a, between the reaction chamber 1 and the battery
cover 23b, and between the condensation/evaporation chamber 3 and
the condensation/evaporation chamber 3' are disregarded.
[0226] With respect to the communication part 5 communicating
between the reaction chamber 1 and the condensation/evaporation
chamber 3 and also the communication part 5' communicating between
the reaction chamber 1' and the condensation/evaporation chamber
3', heat transfer between them is disregarded.
[0227] The condensation/evaporation chamber 3 and the
condensation/evaporation chamber 3' are thermally isolated from
other members.
In the Case of CPU Heat Generation Amount of 7 W
Example 2
[0228] Assuming the heat generation amount of the CPU 21a in the
electronic apparatus model 32 at 7 W, simulation of heat balance
was conducted by applying the analytical method comprising the
various conditions/assumptions described above. In this simulation,
the chemical heat pumps 10 and 10' was intended not to be operated
at the first, and then the chemical heat pump 10 was intended to be
operated at heat release process and at the same time the chemical
heat pump 10' was intended to be operated at heat release process.
Specifically, it is explained as follows.
[0229] First, based on the initial conditions (t=0), simulation was
conducted by assuming the heat generation amount of the CPU 21a at
7 W and not operating the chemical heat pumps 10 and 10' until the
temperature of the CPU 21a reached to 120.degree. C. As the
results, the temperatures of the CPU 21a and the reaction chamber 1
(its container and inside) reached to 120.degree. C. at t=800
seconds.
[0230] Then (subsequently to the time point of t=800 seconds),
simulation was conducted by assuming the heat generation amount of
the CPU 21a at 7 W until calcium sulfate hemihydrate in the
reaction chamber 1 at 120.degree. C. generated water vapor by
absorbing heat to reach the reaction rate of 100%. As the results
of this simulation, the followings were shown. In the reaction
chamber 1, calcium sulfate hemihydrate absorbed heat at the level
of 1.3 W on average to emit water vapor continuously (heat
storage), and during t=800 to 1,300 seconds (500 seconds after the
start of absorbing heat) the temperatures of the CPU 21a and the
reaction chamber 1 (its container and inside) were maintained at
about 120.degree. C. The water vapor generated during this time
moved to the condensation/evaporation chamber 3 and emitted heat at
the level of 1.6 W as the latent heat on changing into liquid
water, but the condensation/evaporation chamber 3 was cooled by the
condensation/evaporation chamber 3' thermally combined therewith
and maintained at about 25.degree. C. Thus, the chemical heat pump
10 operated at the heat storage process during t=800 to 1300
seconds (reaction rate of 100%) and was able retain the temperature
of the CPU 21a at about 120.degree. C.
[0231] At the same time (subsequently to the time point of t=800
seconds), simulation was conducted until water in the
condensation/evaporation chamber 3 evaporated and the time passed
to reach t=1,300 seconds. As the results of this simulation, the
followings were shown. The water in the condensation/evaporation
chamber 3' absorbed heat at the level of 2.1 W as the latent heat
on changing into water vapor, and the water vapor generated thereby
moved to the reaction chamber 1' and reacted with calcium sulfate
to generate heat (heat release) at the level of 1.7 W. At t=1,190
seconds (390 seconds after the start of generating heat) the
reaction rate reached to 100% and the heat release in the reaction
chamber 1' was completed. During t=800 to 1,190 seconds, the
temperature of the condensation/evaporation chamber 3' (its
container and inside) was maintained at about 25.degree. C. The
temperature of the battery cover 23b was increased to about
52.degree. C. at t=1,300 at most, due to effect by a sensible heat
of calcium sulfate/calcium sulfate hemihydrate. This was lower the
temperature of the battery cover 23b in the comparative example in
Simulation model 1 described above by 1.degree. C. Thus, the
chemical heat pump 10' operated at the heat release process during
t=800 to 1,190 seconds (reaction rate of about 100%).
[0232] Therefore, according to this simulation, it was found that
by equipment of the chemical heat pumps 10 and 10', even in the
case where the CPU heat generation amount is extremely large as 7
W, the CPU was kept not to exceed 120.degree. C. for the time
duration of approximately 1,300 seconds from the start of heat
generation by the CPU.
[0233] The present invention can be suitably applied to mobile
electronic devices such as smartphones, cellular phones, tablet
devices, laptop computers, portable game machines, portable music
players, and digital cameras, but is limited thereto.
[0234] This application claims priority to and the benefit of
Japanese Patent Application No. 2012-173042, filed Aug. 3, 2012,
the entire contents of which is incorporated herein by reference.
[0235] 1, 1a, 1b, 1' Reaction chamber [0236] 2a Solid phase
(including a chemical heat storage material) [0237] 2b Gas phase
(including a condensable component) [0238] 3, 3a, 3b, 3'
Condensation/evaporation chamber [0239] 4a Gas phase (including a
condensable component) [0240] 4b Liquid phase (including a
condensable component) [0241] 5, 5a, 5b, 5c, 5' Communication part
[0242] 10, 10' Chemical heat pump (device) [0243] 11 Heat
generating element [0244] 13 Heat conductive member [0245] 20, 21,
22, 23, 24 Electronic apparatus [0246] 21a CPU [0247] 21b Power
management IC [0248] 22 Electronic circuit board [0249] 23a Chassis
[0250] 23b Battery cover [0251] 24 Battery [0252] 25 Camera unit
[0253] 26 Display [0254] 28 Human body [0255] 29 Ambient atmosphere
(air) [0256] 30, 31, 32 Electronic apparatus model
* * * * *