JP7242011B2 - heat exchanger - Google Patents

Description

The present invention relates to an adsorption heat exchange device.

2. Description of the Related Art Conventionally, a heat exchange device has been widely used for heating or cooling an object (a space or an object) by transferring heat. For example, Patent Document 1 below discloses an adsorption type heat exchange having an evaporator that vaporizes a medium, an adsorber that includes an adsorbent that desorbs and adsorbs the vaporized medium, and a condenser that condenses the vaporized medium. An apparatus is disclosed.

JP 2015-183930 A

The conventional adsorption heat exchange device as disclosed in the above Patent Document 1 uses the latent heat of the medium in the evaporator or condenser as cold heat or heat. A large amount of energy is required for heating and cooling. Energy is also required for heating to regenerate the adsorbent that has adsorbed the medium. As a result, the coefficient of performance COP is lowered. For this reason, a larger amount of medium is required to obtain desired cooling and heating. As the amount of medium increases, the amount (volume) of adsorbent also increases. Furthermore, the need for an evaporator and a condenser results in an increase in the size of the heat exchange device. For this reason, it has been difficult to apply the conventional adsorption-type heat exchange device to applications such as car air conditioners, in which the installation space is particularly limited.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an adsorption type heat exchange apparatus that can improve the coefficient of performance COP and reduce the size of the apparatus.

The present inventors have made intensive studies to solve the above problems. In the process, we discovered a nanoporous body that can be mechanically deformed to desorb and adsorb media by applying and releasing stress. Furthermore, the inventors discovered that it is possible to generate latent heat by desorbing and adsorbing the medium on the nanoporous material, thereby changing the phase of the medium. Then, an attempt was made to use the nanoporous body as an adsorbent for a heat exchange device. As a result, the inventors have found that the latent heat generated by desorption or adsorption can be directly used for cooling or heating, and that the above problems can be solved, leading to the completion of the present invention.

The heat exchange device according to the present invention includes a nanoporous body having elasticity, capable of desorbing a medium by contraction, and capable of absorbing a medium by expansion, and shrinking by applying stress to the nanoporous body. and a heat exchanging portion comprising a chamber containing a nanoporous body therein. The heat exchange device further includes a control unit for controlling the operation of the stress applying unit to switch the operation mode in the heat exchange unit between the desorption mode and the adsorption mode. Here, the detachment mode is an operation mode in which stress is applied to the nanoporous body to shrink it and detach the medium from the nanoporous body. The desorption mode is an operation mode in which stress is released to expand the nanoporous body and adsorb the medium to the nanoporous body.

According to the heat exchange device of the present invention, stress is applied and released to the nanoporous body to contract and expand, thereby causing the nanoporous body to desorb and adsorb the medium, thereby generating latent heat due to phase change. can be done. As a result, the latent heat generated by the desorption and adsorption of the medium can be directly used for cooling or heating, thus eliminating the need for an evaporator or condenser. In addition, since the evaporator and condenser do not require depressurization or heating/cooling in order to obtain latent heat, the energy required for the thermal cycle can be reduced. As a result, the coefficient of performance COP can be improved, and the amount of nanoporous material used can be reduced. In this way, an evaporator and a condenser are not required, and the amount of nanoporous material can be reduced, so that the size of the heat exchange device can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows the structure of the heat-exchange apparatus which concerns on 1st Embodiment. It is a figure for demonstrating the principle of the adsorption action of a solid surface. It is a figure for demonstrating the principle of the adsorption action of the nanoporous body which concerns on this embodiment. FIG. 4 is a state diagram of refrigerant; FIG. 4 is a diagram showing how the nanoporous body is contracted to desorb the refrigerant. FIG. 3 is a diagram showing how a nanoporous body is allowed to expand freely to adsorb a refrigerant. FIG. 4 shows a TS diagram of the heat cycle of the heat exchange device according to the first embodiment; It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic sectional view for demonstrating operation|movement of the heat-exchange apparatus which concerns on 1st Embodiment. It is a schematic diagram showing the configuration of a heat exchange device according to the contrast. FIG. 2 is a diagram showing stress-volume strain curves of samples prepared in Example 1 and Comparative Example. 1 is a photograph showing how stress is applied and released to samples prepared in Example 1 and Comparative Example. FIG. 2 is a schematic diagram showing a press chamber apparatus for confirming water desorption/adsorption of nanoporous materials by applying/releasing stress. FIG. 2 is a diagram showing desorption/adsorption isotherms of water with stress applied and without stress applied for samples prepared in Example 1 and Comparative Example. FIG. 10 is a diagram showing the results of measurement of changes in water vapor pressure when stress application/releasing is repeated on the sample of Example 1. FIG. 1 is a diagram showing a water adsorption isotherm of a sample of Example 1. FIG. FIG. 10 is a diagram representing a stress-strain curve of a nanoporous material; FIG. 4 is a diagram showing the relationship between the coefficient of performance COP and Young's modulus E of the heat exchanger according to the embodiment of the present invention; FIG. 10 is a diagram showing ethanol desorption/adsorption isotherms of the sample prepared in Example 2 with stress applied and without stress applied. FIG. 16 shows a desorption/adsorption isotherm of ethanol when stress is applied to the sample during the desorption measurement when measuring the desorption/adsorption amount of ethanol of the sample prepared in Example 2 shown in FIG. It is a diagram. It is a schematic sectional drawing which shows the structure of the heat-exchange apparatus which concerns on 2nd Embodiment. FIG. 7 is a schematic cross-sectional view for explaining the operation of the heat exchange device according to the second embodiment; FIG. 7 is a schematic cross-sectional view for explaining the operation of the heat exchange device according to the second embodiment; FIG. 7 is a schematic cross-sectional view for explaining the operation of the heat exchange device according to the second embodiment; FIG. 7 is a schematic cross-sectional view for explaining the operation of the heat exchange device according to the second embodiment; FIG. 10 is a diagram representing a stress-strain curve of a nanoporous material; It is a schematic sectional drawing which shows the structure of the heat-exchange apparatus which concerns on the modification of 2nd Embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention should be determined based on the description of the claims and is not limited only to the following embodiments. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

[First embodiment]
<Heat exchange device>
The heat exchange device 10 according to the first embodiment of the present invention desorbs and adsorbs the refrigerant (medium) 60 by mechanically deforming the nanoporous body 20 by applying and releasing stress. It is characterized in that cold heat obtained from latent heat of vaporization generated when the coolant 60 is desorbed is used to cool the object. The heat exchange device 10 can be applied, for example, to a car air conditioner (cooling) that cools the interior (inside air) of a car.

As shown in FIG. 1, the heat exchange device 10 has a pair of heat exchange sections 30A and 30B (a first heat exchange section 30A and a second heat exchange section 30B), and a control section 40 that controls the operation of the entire device. . The control unit 40 performs swing operation so that while one of the pair of heat exchange units 30A and 30B is in the desorption mode, the other is in the adsorption mode. Thereby, cold heat can be continuously generated in the heat exchange units 30A and 30B in the desorption mode. Here, the “desorption mode” is an operation mode in which the coolant 60 is desorbed from the nanoporous body 20 . Also, the “adsorption mode” is an operation mode in which the refrigerant 60 is adsorbed on the nanoporous body 20 .

The heat exchange device 10 has a pipe 50 that allows the refrigerant 60 to move between the first chamber 32A and the second chamber 32B, and a valve 51 that switches the pipe 50 between a communication state and a cutoff state. When the valve 51 is opened, the pipe 50 is in a communicating state, and when the valve 51 is closed, the pipe 50 is in a blocked state.

[Heat exchange parts 30A and 30B]
As shown in FIG. 1, the first heat exchange section 30A has a first nanoporous body 20A, a first stress applying section 31A, a first chamber 32A, and a first air conditioning section 33A. Similarly, the second heat exchange section 30B has a second nanoporous body 20B, a second stress applying section 31B, a second chamber 32B, and an air conditioning section 33B.

The first heat exchange section 30A and the second heat exchange section 30B have the same configuration. In the following description, the first heat exchange section 30A and the second heat exchange section 30B are collectively referred to as "heat exchange sections 30A and 30B." Similarly, the first stress applying section 31A and the second stress applying section 31B are collectively referred to as "stress applying sections 31A and 31B". Also, the first chamber 32A and the second chamber 32B are collectively referred to as "chambers 32A, 32B". Also, the first air conditioning section 33A and the second air conditioning section 33B are collectively referred to as "air conditioning sections 33A and 33B". Also, the first nanoporous body 20A and the second nanoporous body 20B are collectively referred to as "nanoporous body 20".

[Nanoporous body 20]
The nanoporous body 20 is made of a nanoporous material that has elasticity, can desorb the refrigerant 60 by contraction, and can adsorb the refrigerant 60 by expansion. The nanoporous body 20 is stressed by the stress-applying portions 31A and 31B, shrinks, releases the coolant 60, and expands freely to adsorb the coolant 60 when the stress is released.

Here, “elasticity” means the property of reversibly deforming greatly and recovering to almost the original shape by releasing the stress even if the stress applying portions 31A and 31B apply stress from the outside to shrink it. means The elastic limit of nanoporous body 20 is designed to be greater than the stress application required to desorb coolant 60 . It is preferable that the elastic limit of the nanoporous body 20 is appropriately designed according to the cooling scale of the object to which the heat exchange device 10 is applied.

In addition, "nanoporous" means having a plurality of nano-level pores. Nano-level pores are preferably micropores or mesopores with diameters of preferably 0.5 to 100 nm, more preferably 0.7 to 50 nm, and even more preferably 0.7 to 6 nm. In IUPAC (International Union of Pure and Applied Chemistry), pores with a diameter of 2 nm or less are micropores, pores with a diameter of 2 to 50 nm are mesopores, and pores with a diameter of 50 nm or more are macropores ( macropore).

From the viewpoint of reducing the workload of the stress applying parts 31A and 31B required for shrinking the nanoporous body 20, the Young's modulus of the nanoporous body 20 is preferably designed to be 1.1 GPa or less. The reason why the Young's modulus is designed to be 1.1 GPa or less will be described later.

As shown in FIG. 2A, a solid surface generally has high potential energy due to van der Waals force, and has the effect of condensing the molecules of the coolant 60 . In particular, in the nanoporous body 20 according to the present embodiment, as shown in FIG. 2B, the refrigerant 60 adsorbed to the nanoporous body 20 is surrounded by small nano-level pore walls, so that the solid surface The potential energy due to van der Waals force (physical adsorption force) is remarkably high. At this time, the gaseous refrigerant 60 is adsorbed on the pore walls of the nanoporous body 20 at the liquid density. That is, the adsorption to the nanoporous body 20 is a phenomenon similar to the phase change from gas to liquid, and the heat of adsorption is almost equal to the latent heat of condensation.

In the following description, the refrigerant 60 undergoes a phase change from gas to liquid when adsorbed on the nanoporous body 20, and undergoes a phase change from liquid to gas when desorbed. Also, the heat of adsorption is assumed to be equal to the latent heat of condensation. The phase change due to the desorption and adsorption of the refrigerant 60 to the nanoporous body 20 was confirmed in Examples described later.

FIG. 3 shows a state diagram of refrigerant 60 . As indicated by the dotted line in FIG. 3, the liquid-density coolant 60 inside the pores adsorbed on the pore walls of the nanoporous body 20 is in equilibrium with the vapor at a pressure lower than the saturated vapor pressure. . That is, the gas adsorbed on the pore walls of the nanoporous body 20 becomes liquid at a pressure lower than the saturated vapor pressure.

FIG. 4A is a diagram showing how the nanoporous body 20 is contracted to desorb the refrigerant 60. FIG. As shown in FIG. 4A, when stress is applied (work W _ns [J]) to the nanoporous body 20, the pores contract and the refrigerant 60 adsorbed on the pore walls is desorbed. At this time, the refrigerant 60 adsorbed by the liquid density is released to the outside of the nanoporous body 20 again as a gas. The heat exchange device 10 can cool the object by using the latent heat of vaporization Q _L [J] during this desorption as cold heat.

FIG. 4B is a diagram showing how the contracted nanoporous body 20 is allowed to expand freely to adsorb the coolant 60 . As shown in FIG. 4B, when the nanoporous body 20 is released from the stress, the nanoporous body 20 expands freely, the pores return to their original size, and the refrigerant 60 can be adsorbed again. As described above, the coolant 60 is adsorbed on the pore walls of the nanoporous body 20 at liquid density. That is, the refrigerant 60 undergoes a phase change from gas to liquid when adsorbed by the nanoporous body 20, and generates latent heat of condensation _QH [J].

The material constituting the nanoporous body 20 is not particularly limited as long as it is elastic, capable of desorbing the refrigerant 60 by shrinking, and capable of adsorbing the refrigerant 60 by expanding. Examples of such materials include zeolite template carbon (ZTC), graphene meso sponge (GMS), and the like. Zeolite template carbon (hereinafter referred to as “ZTC”) and graphene meso-sponge (hereinafter referred to as “GMS”) are both composed of a single-layer graphene skeleton and have porosity necessary for desorption and adsorption of the refrigerant 60. and elastic properties.

A ZTC is composed of a single-layer graphene sheet. In addition, uniform pores (diameter about 1.2 nm) are arranged three-dimensionally and interconnected, and have extremely high BET specific surface area and pore volume (maximum BET specific surface area is 4100 m ² / g, pore volume of 1.8 cc/g). The ordered structure of ZTC was analyzed using an X-ray diffractometer (Rigaku, MiniFlex600, CuK). In addition, the BET specific surface area of ZTC was analyzed using liquid nitrogen adsorption (77K) (Microtrac BEL, BELSORB-max).

A method for producing ZTC is described in Nishihara, H. et al., Chemistry-European Journal 15, 5355 (2009) and the like. Specifically, first, a porous material (for example, zeolite, etc.) having a structure in which the pores are interconnected in a mesh-like manner is prepared as a template. Then, an organic compound (e.g., acetylene, ethylene, etc.) is introduced into the surface of the porous material and inside the pores under heating conditions, and the organic compound is carbonized by heating to deposit carbon on the porous material. Let Here, the carbonization of the organic compound and the deposition of carbon can be performed by, for example, a chemical vapor deposition (CVD) method. Then, the porous material that is the template is removed. By this method, a carbon material (that is, ZTC) reflecting the three-dimensional structure of the template can be easily produced. The ZTC produced by the above method has excellent flexibility and elasticity, and can be reversibly elastically deformed from about 1.2 nm to about 0.7 nm in pore diameter.

GMS is also a sponge-like mesoporous material with pore walls mostly composed of single-layer graphene and having fine pores of about 6 nm. (about 2000 m ² /g). On the other hand, unlike activated carbon and carbon black, it also has excellent corrosion resistance (oxidation resistance) because it contains almost no edges of graphene that cause corrosion. In addition, due to the flexible and tough properties of graphene, GMS has excellent flexibility and elasticity, and can undergo reversible elastic deformation from a pore diameter of about 5.8 nm to about 0.7 nm. can.

A method for producing GMS is described in Nishihara, H. et al., Advanced Functional Materials, Vol. 26, 2016, 6418-6427. Specifically, first, metal oxide nanoparticles made of alumina or the like (eg, γ-alumina) are prepared as nano-sized spherical substrates. This material has high catalytic activity for carbon coating by the CVD method, which will be described later, and excellent resistance to sintering.

Subsequently, the surface of the spherical substrate (metal oxide nanoparticles) prepared above is coated with carbon by a CVD method using an organic compound as a carbon source. According to carbon coating using this CVD method, it is possible to form a uniform carbon layer on the entire surface of the spherical substrate (metal oxide nanoparticles). Examples of organic compounds used in this case include methane, acetylene, ethylene, propylene, and benzene. Among them, methane is preferred as a carbon source from the viewpoint that a large amount of carbon crystal coating can be achieved. It is preferable to use In the CVD process, the organic compound may be introduced in a state in which a spacer such as quartz sand (silica sand) is mixed with the spherical base material (metal oxide nanoparticles) for the purpose of improving the gas flow. Also, an inert gas such as nitrogen may be used as a carrier gas for introducing the organic compound, and the concentration of the carbon source in the mixed gas of the carrier gas and the carbon source (organic compound) is about 10 to 30% by volume. is preferred.

As the CVD process progresses, the color of the sample changes to black, while the reaction vessel (e.g., quartz tube) containing the sample remains transparent. ) can be confirmed to occur only on the surface. Here, since the spherical substrate (metal oxide nanoparticles) is not sintered even after the CVD process, the shape of the carbon-coated spherical substrate hardly changes from before the carbon coating. The (average) stacking number of the carbon layers coated on the surface of the spherical base material (metal oxide nanoparticles) in this way depends on the amount of the carbon source (organic compound) input in the CVD process, as well as the amount of the CVD process. It can be controlled based on the treatment temperature, treatment time, etc., and corresponds to the (average) number of stacked graphene layers in the finally obtained GMS. The value of this (average) lamination number is not particularly limited, but from the viewpoint of exhibiting excellent desorption/adsorption characteristics with respect to the refrigerant 60, it is preferably 0.90 to 3.0, more preferably 0.95. to 2.0, more preferably 0.98 to 1.5, and particularly preferably 1.0 to 1.1. The processing temperature and processing time in the CVD process are not particularly limited, but the processing temperature is preferably 800 to 1000.degree. C., more preferably 850 to 950.degree. Also, the treatment time is preferably 1 to 10 hours, more preferably 2 to 6 hours.

After that, the spherical substrate (metal oxide nanoparticles) used as the template is removed by chemical etching, leaving only the carbon layer coated on the surface of the spherical substrate. At this time, an aqueous solution of strong acid or strong base may be used for chemical etching. Examples of strong acids include hydrofluoric acid (HF) (in this case, etching at room temperature is possible). Also, examples of strong bases include sodium hydroxide (NaOH) (in this case, heating to about 200 to 300° C. is preferred). When the spherical substrate (metal oxide nanoparticles) is removed by chemical etching, Carbon MesoSponges (CMS) with spherical mesopores are obtained as precursors of GMS.

Finally, after washing the carbon meso-sponge (CMS) thus obtained with water as necessary, it is heated at a temperature of about 1500 to 2000° C. (preferably 1700 to 1900° C.) for 30 minutes or more under reduced pressure conditions. Heat treatment is performed for about 2 hours. Thereby, crystallization of the carbon layer into graphene proceeds to obtain GMS. Here, since the spherical mesopores of the carbon meso-sponge (CMS) are extremely stable even at high temperatures during the heat treatment described above, the carbon meso-sponge (CMS ) retains the same mesopores. Since GMS has such mesopores, it can be flexibly elastically deformed like a sponge. Therefore, it can shrink to desorb the refrigerant 60 and expand to adsorb the refrigerant 60, and can be suitably used as the nanoporous body 20 in the heat exchange device 10 according to the present embodiment.

[Stress applying parts 31A and 31B]
The stress-applying parts 31A and 31B apply stress to the nanoporous body 20 to contract it as shown in FIG. 4A, and release the applied stress to allow the nanoporous body 20 to expand freely as shown in FIG. 4B. . Thereby, the stress-applying parts 31A and 31B can control the pore diameter of the nanoporous body 20 by external stress.

The configuration of the stress-applying parts 31A and 31B is not particularly limited as long as they can reciprocate toward and away from the nanoporous body 20 to apply and release stress to the nanoporous body 20 . As the stress applying units 31A and 31B, for example, a mechanical press using rotational motion of a motor, a hydraulic press using fluid pressure such as oil pressure, or the like can be used.

[Chambers 32A, 32B]
The chambers 32A and 32B are containers having a space for accommodating the nanoporous body 20 inside. The interiors of the chambers 32A and 32B are maintained at a vacuum or a low pressure close to vacuum. Therefore, the refrigerant 60 can undergo a phase change from liquid to gas at relatively low temperatures (see FIG. 3).

[Air control units 33A and 33B]
The air control units 33A and 33B switch between a cooling state in which heat is conducted with low-temperature air in the chambers 32A and 32B and an exhaust heat state in which heat is conducted with high-temperature air. Since the heat exchange device 10 of this embodiment is a device for cooling an object, low-temperature air corresponds to the atmosphere of the object to be cooled. The air conditioning units 33A and 33B take out the cold heat required to cool the target from the heat exchange units 30A and 30B. In addition, the air conditioning units 33A and 33B are placed in an exhaust heat state to exhaust the heat generated from the heat exchange units 30A and 30B.

When the heat exchange device 10 is applied to a car air conditioner (cooling) of an automobile, for example, the low-temperature air can be used as the vehicle interior air (inside air), and the high-temperature air can be used as the vehicle exterior air (outside air). In the summer when air conditioning is used, the outside temperature is higher than the inside temperature, for example, the outside temperature is about 303K and the inside temperature is about 298K. In the following description, low-temperature air will be referred to as "inside air" inside the vehicle compartment, and high-temperature air will be referred to as "outside air" outside the vehicle compartment.

[Control unit 40]
The control unit 40 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a computer-readable recording medium (not shown). A series of processes for realizing the control described later is recorded in a recording medium or the like in the form of a program. , the control described later is realized.

The control unit 40 controls the operations of the stress applying units 31A and 31B and the air conditioning units 33A and 33B. The control unit 40 switches the operation mode of the heat exchange units 30</b>A and 30</b>B between a desorption mode in which the refrigerant 60 is desorbed from the nanoporous body 20 and an adsorption mode in which the nanoporous body 20 adsorbs the refrigerant 60 .

[Refrigerant 60]
Water is used as the coolant 60 in this embodiment. Fluorocarbon-based HFC-134a is widely used as a refrigerant in general vapor compression type heat exchangers. The general operating pressure is 0.34 to 1.2 MPa and the temperature range is 277 to 323 K. Although operation at high pressure is required, it is possible to operate near room temperature, and its coefficient of performance COP is 5. ~7. On the other hand, since water has a latent heat of vaporization about 16 times that of HFC-134a, theoretically, the cold heat obtained is 16 times that of HFC-134a. Fluorocarbon refrigerants such as HFC-134a have improved the problem of ozone depletion, but still have a large global warming potential. On the other hand, natural refrigerants represented by water do not adversely affect the global environment.

For the above reasons, by using water as the refrigerant 60, it is possible to improve the coefficient of performance COP and provide the heat exchange device 10 that is friendly to the global environment.

Note that the coolant 60 applicable to the present invention is not limited to water, and ethanol may be used, for example, as in Example 2 described later.

<Heat cycle of heat exchange device 10>
Next, with reference to FIG. 5, the heat cycle by the heat exchange device 10 will be described. FIG. 5 shows a TS diagram of the thermal cycle of the heat exchange device 10. As shown in FIG. In the present invention, the refrigerant 60 is classified into the following four types. The first type is the part that stays permanently adsorbed on the nanoporous body 20 , and this is referred to as the refrigerant 61 . The second type is the refrigerant 62 , which is desorbed and adsorbed by applying stress to the nanoporous body 20 and by free expansion and not involved in cooling the internal air. The third type is the refrigerant 63 that is involved in the cooling of the inside air among those that are desorbed and adsorbed by stress application and free expansion to the nanoporous body 20 . The fourth type is a portion that permanently exists as a gaseous phase without being adsorbed on the nanoporous body 20 , and is referred to as a refrigerant 64 . It should be noted that only the coolant 63 is considered in FIG.

The thermal cycle of the heat exchange device 10 is a reverse Carnot cycle. The reverse Carnot cycle changes the state of the refrigerant 63 in the order of state 1→state 2→state 3→state 4. FIG. In FIG. 5, the process from state 1 to state 2 is heating, the process from state 2 to state 3 is isobaric isothermal adsorption, the process from state 3 to state 4 is cooling, and the process from state 4 to state 1 is isobaric isothermal. Each step of desorption is shown. Here, the refrigerant 63 is a saturated vapor with a low temperature _T1 in state 1, a superheated vapor with a high temperature _T2 in state 2, a liquid with a high temperature _T3 in state 3, and a liquid with a low temperature T4 in state ₄ . is. Here, temperatures _T1 and _T4 are equally T _L and temperatures _T2 and _T3 are equally T _H.

From state 1 to state 2, the refrigerant 63 is heated from saturated vapor of low temperature T _L to superheated vapor of high temperature T _H . At this time, the temperature of the refrigerant 63 rises without undergoing a phase change while remaining gaseous. At the same time, sensible heat Q _sh1-2 [J] is absorbed to raise the temperature of the coolant 61 and the nanoporous body 20 from T _L to T _H . Note that the refrigerant 63 is gas, and its sensible heat is smaller than that of the liquid refrigerant 61, so it can be ignored. In the heat cycle of the heat exchange device 10 , “sensible heat” includes not only the amount of heat required to change the temperature of the refrigerant 61 but also the amount of heat required to change the temperature of the nanoporous body 20 .

From State 2 to State 3, the contracted nanoporous body 20 expands freely, and the coolant 63 is adsorbed in the pores of the nanoporous body 20 (see FIG. 4B). Due to the adsorption, the refrigerant 63 undergoes a phase change from gas (steam) to liquid (water). Condensation latent heat Q _H [J] is exhausted with the phase change.

From state 3 to state 4, the refrigerant 63 is cooled from a hot T _H liquid to a cold T _L liquid. At this time, the temperature of the refrigerants 61 and 63 decreases without undergoing a phase change while remaining liquid. The sensible heat Q _sh [J] is exhausted to lower the temperature of the refrigerants 61, 63 and the nanoporous body 20 from T _H to T _L . In states 3 and 4, the refrigerant 63 is in a state of being adsorbed within the pores. In addition, between state 3 and state 4, the refrigerant 62, which is a gas, is adsorbed by the nanoporous body 20A as the temperature drops, so the gas phase pressure of the system drops once, but the nanoporous body 20 contracts. The gas phase pressure of the system is returned to the original state by desorbing the refrigerant 62 .

From State 4 to State 1, the nanoporous body 20 is contracted to desorb the coolant 63 (see FIG. 4A). The external work required to shrink the nanoporous body 20 from state 3 to state 4 and the external work required to shrink the nanoporous body 20 from state 4 to state 1 Let W _ns [J] be the sum of the work of Further, the desorption causes the refrigerant 63 to undergo a phase change from liquid (water) to gas (water vapor). The latent heat of vaporization Q _L [J] is absorbed with the phase change. The heat exchange device 10 can cool the object by using the latent heat of vaporization Q _L [J] as cold heat.

<Method for controlling heat exchange device 10>
Next, a control method for the heat exchange device 10 of this embodiment will be described with reference to FIGS. 6A to 6H. In the following description, states 1 to 4 mean states 1 to 4 shown in FIG. The control unit 40 controls the operations of the stress applying units 31A and 31B and the air conditioning units 33A and 33B.

As shown in FIGS. 6A to 6H, in the heat exchange device 10 of the present embodiment, while the operation mode of one of the pair of heat exchange units 30A and 30B is in the desorption mode, the other heat exchange unit is in the desorption mode. Swing operation is performed so that the operation mode of the part becomes the adsorption mode.

"Internal air" in FIGS. 6A to 6H indicates a state in which heat is conducted between the interiors of the chambers 32A and 32B and the low-temperature air (vehicle interior air) to be cooled by the air conditioning units 33A and 33B. "Outside air" in FIGS. 6A to 6H indicates a state in which heat is conducted between the chambers 32A and 32B with high-temperature air (vehicle outside air) by the air control units 33A and 33B. Illustration of the air conditioning units 33A and 33B is omitted.

[First heat exchange part 30A: desorption mode, second heat exchange part 30B: adsorption mode]
6A to 6C show the heat exchange device 10 with the first heat exchange section 30A in the desorption mode and the second heat exchange section 30B in the adsorption mode.

(Start of desorption mode/adsorption mode)
FIG. 6A shows the state at the start of the desorption mode of the first heat exchange section 30A and the adsorption mode of the second heat exchange section 30B. At this time, the refrigerant 63 in the first chamber 32A is between states 3 and 4, and the refrigerant 63 in the second chamber 32B is in the middle between states 1 and 2, respectively. The first nanoporous body 20A in the first chamber 32A is in a state of free expansion without application of stress from the first stress applying section 31A. The second nanoporous body 20B in the second chamber 32B is in a contracted state due to the application of stress from the second stress applying section 31B. Note that the valve 51 is in a closed state.

The refrigerants 62 and 63 in the first chamber 32A are in a state of being completely adsorbed by the first nanoporous body 20A at a temperature _T4 . At this time, the gas phase pressure in the first chamber 32A is lower than states 3 and 4. The refrigerants 62 and 63 in the second chamber 32B are in a state of having completely desorbed from the second nanoporous body 20B at temperature _T2 . At this time, the gas phase pressure of the second chamber 32B is higher than the states 2 and 3. Even in the first chamber 32A where adsorption is completed, the refrigerant 64 remains in a gaseous state without being adsorbed. Similarly, even in the second chamber 32B where the desorption is completed, the refrigerant 61 remains in a state of being permanently adsorbed inside the nanoporous body 20 in a liquid state without being desorbed. As for the refrigerant 61 permanently remaining in the nanoporous body 20, only the sensible heat change is considered in the calculation of the coefficient of performance COP described later.

In the first heat exchange section 30A, heat is conducted between the inside of the first chamber 32A and the internal air to be cooled. In the second heat exchange section 30B, heat is conducted between the inside of the second chamber 32B and the outside air.

The temperature _T4 within the first chamber 32A is lower than the temperature _T2 within the second chamber 32B. Also, the internal pressure of the first chamber 32A is lower than the internal pressure of the second chamber 32B. Therefore, the valve 51 is closed.

When the first heat exchanging part 30A starts the desorption mode, the first stress applying part 31A applies compressive stress to the first nanoporous body 20A to shrink the first nanoporous body 20A. As a result, the pores of the first nanoporous body 20A are shrunk and the coolant 62 is desorbed.

In the heat exchange device 10, the first heat exchange section 30A and the second heat exchange section 30B are alternately in the desorption mode. is the work W _ns [J] required to desorb 62 and 63;

Refrigerant 60 increases the pressure in first chamber 32A by desorption, bringing the system to state 4. As the refrigerant 62 changes phase, latent heat of vaporization Q _L3-4 [J] is generated. As will be described later, this latent heat of vaporization Q _L3-4 [J] is used to offset the latent heat of condensation Q _H3-4 [J] of refrigerant 62 shown in FIG. 6H, and is not used as cold heat.

On the other hand, when the adsorption mode is started, the second heat exchange section 30B releases the stress applied from the second stress applying section 31B to the first nanoporous body 20A. As a result, the second nanoporous body 20B expands freely to restore the original shape of the pores, and at the same time adsorbs the refrigerant 62 present as vapor. The pressure in the second chamber 32B then decreases and the system reaches state 2. Condensation latent heat Q _H1-2 [J] is generated with the phase change. The latent heat of condensation Q _H1-2 [J] is exhausted to the outside air by the air control section 33B.

During the above process, the internal pressure (vapor pressure) of the first chamber 32A increases, while the internal pressure (vapor pressure) of the second chamber 32B decreases. At the start of the process, the internal pressure of the first chamber 32A is lower than the internal pressure of the second chamber 32B, so the internal pressure of the first chamber 32A approaches the internal pressure of the second chamber 32B.

(open valve 51)
As shown in FIG. 6B, the valve 51 is opened when the internal pressure of the first chamber 32A and the internal pressure of the second chamber 32B become equal. At this time, the coolant 63 in the first chamber 32A is in state 4, and the coolant 63 in the second chamber 32B is in state 2. After the valve 51 is opened, the desorbed saturated steam in state 1 in the first chamber 32A moves to the second chamber 32B via the pipe 50 and changes to superheated steam at temperature _T2 . In this manner, the saturated vapor refrigerant 63 is continuously supplied from the first chamber 32A to the second chamber 32B. The enthalpy change (H ₃ −H ₂ ) from state 2 to state 3 corresponds to the amount of heat Q _H [J] exhausted from the second chamber 32B to the outside air.

In the first heat exchange portion 30A, latent heat of vaporization Q _L [J] is generated by desorption of the refrigerant 63 . The latent heat of vaporization Q _L [J] after opening the valve 51 is utilized as cold heat for cooling the inside air.

(End of desorption mode/adsorption mode; close valve 51)
FIG. 6C shows a state where the second nanoporous body 20B has reached a limit where it can no longer expand freely. In this state, the adsorption mode of the second heat exchange section 30B ends. Simultaneously with the end of the adsorption mode, the first heat exchange section 30A stops applying stress to the first nanoporous body 20A and ends the desorption mode. After finishing the desorption/adsorption mode, the valve 51 is closed.

At the stage when the desorption mode and the adsorption mode are finished, the refrigerant 63 in the first chamber 32A is in state 1 and the refrigerant 63 in the second chamber 32B is in state 3. The temperature T _L in the first chamber 32A remains lower than the temperature T _H in the second chamber 32B. Also, immediately after the valve 51 is closed, the internal pressure of the first chamber 32A and the internal pressure of the second chamber 32B are equal. At this time, part of the coolant 62 is adsorbed on the nanoporous body 20A within the first chamber 32A. Also, part of the refrigerant 62 exists in the gas phase within the second chamber 32B.

[Switch operation mode]
FIG. 6D is a diagram showing a state in which the operation mode of the heat exchange section 30A is switched. The first heat exchange section 30A is switched to adsorption mode, and the second heat exchange section 30B is switched to desorption mode.

In the first heat exchange section 30A, the state in which heat is conducted in the first chamber 32A with the inside air is switched to the state in which heat is conducted with the outside air. In the second heat exchange section 30B, the inside of the second chamber 32B is switched from a state in which heat is conducted with the outside air to a state in which heat is conducted with the inside air. Since the temperature of the outside air is higher than that of the inside air, the temperature inside the first chamber 32A rises from T _L to T _H , and the temperature inside the second chamber 32B drops from T _H to T _L.

In the first heat exchange section 30A, as the temperature in the first chamber 32A rises from _TL to _TH , the temperature of the refrigerant 61 and the first nanoporous body 20A rises from _TL to _TH . Sensible heat Q _sh1-2 [J] is absorbed. Since the sensible heat Q _sh1-2 [J] is absorbed from outside air, it can be ignored in the calculation of the coefficient of performance COP, which will be described later. Also, since the refrigerant 63 changes from state 1 (low temperature gas) to state 2 (high temperature gas), sensible heat is generated.

Also, the physical adsorption amount of the nanoporous body 20 becomes smaller as the temperature becomes higher. Therefore, in the first heat exchanging section 30A, desorption of the refrigerant 62 progresses when the state in which the desorption equilibrium is reached at the temperature T _L is heated to the temperature T _H. Desorption of the refrigerant 62 generates latent heat of vaporization Q _L1-2 [J]. Since the latent heat of vaporization Q _L1-2 [J] absorbs heat from the outside air, it can be ignored in the calculation of the coefficient of performance COP, which will be described later. Note that the pressure in the first chamber 32A becomes higher than the pressures in the states 1 and 2 due to the desorption.

In the second heat exchange section 30B, the refrigerants 61 and 63 change from state 3 (high temperature liquid) to state 4 (low temperature liquid) as the temperature in the second chamber 32B drops from _TH to _TL . Therefore, in the second heat exchange section 30B, sensible heat Q _sh [J] is exhausted to the inside air in order to lower the temperatures of the refrigerants 61 and 63 and the second nanoporous body 20B from _T3 to _T4 . As a result, the sensible heat Q _sh [J] raises the temperature of the inside air to be cooled, resulting in a loss of thermal energy. Therefore, in calculating the coefficient of performance COP, it is necessary to subtract the sensible heat Q _sh [J] from the latent heat of vaporization Q _L [J] obtained as cold heat.

In addition, the physical adsorption amount of the nanoporous body 20 increases as the temperature decreases. Therefore, in the second heat exchanging section 30B, adsorption of the refrigerant 62 progresses when the state where the adsorption equilibrium has been reached at the temperature T _H is cooled to the temperature T _L . Adsorption of the refrigerant 62 generates latent heat of condensation Q _H3-4 [J]. This latent heat of condensation Q _H3-4 [J] raises the temperature of the inside air to be cooled. However, since it can be canceled with the latent heat of vaporization Q _L3-4 [J] shown in FIG. 6E described later, it can be ignored in the calculation of the coefficient of performance COP described later.

The relationship between the amount of physical adsorption of the nanoporous body 20 and the temperature (see FIG. 13) will be described in detail in Examples described later.

Since desorption occurs in the first heat exchange section 30A and adsorption occurs in the second heat exchange section 30B, the internal pressure of the first chamber 32A becomes lower than the internal pressure of the second chamber 32B. At this time, since the valve 51 is in a closed state, it is possible to prevent the refrigerant 60 from flowing back from the low-temperature second chamber 32B to the high-temperature first chamber 32A due to the internal pressure difference between the chambers 32A and 32B. For the above reasons, it is preferable to keep the valve 51 closed when switching the operation modes of the heat exchange units 30A and 30B (see FIG. 6D).

[First heat exchange part 30A: adsorption mode, second heat exchange part 30B: desorption mode]
6E to 6G show the state in which the first heat exchange section 30A is in the desorption mode and the second heat exchange section 30B is in the adsorption mode. 6E to 6G are diagrams in which the operation mode of the first heat exchange section 30A and the operation mode of the second heat exchange section 30B in FIGS. 6A to 6C are interchanged. Since the operation in the desorption mode and the operation in the adsorption mode of the two heat exchange units 30A and 30B are the same, descriptions of matters overlapping with the above description will be omitted by referring to the above description.

(Start of desorption mode/adsorption mode)
FIG. 6E is a diagram in which the operation modes of the heat exchange units 30A and 30B in FIG. 6A are switched. FIG. 6E shows the state at the start of the adsorption mode of the first heat exchange section 30A and the desorption mode of the second heat exchange section 30B. The temperature T _H within the first chamber 32A is higher than the temperature T _L within the second chamber 32B.

In the first heat exchange section 30A in the adsorption mode, the nanoporous body 20 is allowed to expand freely and the refrigerant 62 is adsorbed on the nanoporous body 20, similar to the operation of the second heat exchange section 30B in FIG. 6A. Condensation latent heat Q _H1-2 [J] is generated by the adsorption, which exhausts heat to the outside air.

In the second heat exchange section 30B in the desorption mode, the nanoporous body 20 is contracted by the second stress applying section 31B to desorb the refrigerant 62, similarly to the operation of the first heat exchange section 30A in FIG. 6A described above. Let The desorption generates latent heat of vaporization Q _L3-4 [J] that absorbs heat from the inside air.

During the above process, the internal pressure (water vapor pressure) of the first chamber 32A decreases, while the internal pressure (water vapor pressure) of the second chamber 32B increases. At the start of the process, the internal pressure of the first chamber 32A is higher than the internal pressure of the second chamber 32B, so the internal pressure of the first chamber 32A approaches the internal pressure of the second chamber 32B.

(open valve 51)
FIG. 6F is a diagram in which the operation modes of the heat exchange units 30A and 30B in FIG. 6B are switched. As shown in FIG. 6F, the valve 51 is opened when the internal pressure of the first chamber 32A and the internal pressure of the second chamber 32B become equal. At this time, the coolant 63 in the first chamber 32A is in state 2, and the coolant 63 in the second chamber 32B is in state 4.

Here, the amount of refrigerant 62 adsorbed in the second heat exchange section 30B and the amount of refrigerant 62 desorbed from closing the valve 51 (see FIG. 6C) to opening the valve 51 (see FIG. 6F) are equal. This is because the internal pressure of the first chamber 32A and the internal pressure of the second chamber 32B are the same when the valve 51 is closed and when the valve 51 is opened. Therefore, the latent heat of vaporization Q _L3-4 [J] absorbed from the inside air by the desorption of the second heat exchange unit 30B shown in FIG. Equal to the latent heat Q _H3-4 [J]. Therefore, the latent heat of condensation Q _H3-4 [J] that raises the temperature of the inside air can be offset by the latent heat of vaporization Q _L3-4 [J]. Therefore, the inside air is cooled by the latent heat of vaporization Q _L [J] after the valve 51 is opened.

Let W ₁ [J] be the work to generate the latent heat of vaporization Q _L3-4 [J] that does not contribute to cooling, and W ₂ [J] be the work to generate the latent heat of vaporization Q _L [J] that contributes to cooling. Then, the work W _ns [J] can be expressed by the following formula.

Here, the work W ₁ [J] is not the energy for cooling the object, but the energy required to offset the latent heat of condensation Q _H3-4 [J]. Therefore, it is necessary to consider it in the calculation of the coefficient of performance COP. Therefore, the work W _ns [J] is used in the calculation of the coefficient of performance COP, which will be described later.

Similar to the operation of FIG. 6B described above, the desorbed State 1 saturated steam in the second chamber 32B moves to the first chamber 32A via the pipe 50 and changes to State 2 superheated steam. Thereby, the coolant 60 is continuously supplied from the second chamber 32B to the first chamber 32A.

(End of desorption mode/adsorption mode; close valve 51)
FIG. 6G is a diagram in which the operation modes of the heat exchange units 30A and 30B in FIG. 6C are switched. After completing the adsorption mode of the first heat exchange section 30A and the desorption mode of the second heat exchange section 30B, the valve 51 is closed. At this time, the temperature T _H within the first chamber 32A remains higher than the temperature T _L within the second chamber 32B.

[Switch operation mode]
FIG. 6H is a diagram showing a state of switching the operation mode of the heat exchange section 30A. The first heat exchange section 30A is switched to the desorption mode, and the second heat exchange section 30B is switched to the adsorption mode.

In the first heat exchange section 30A, the inside of the first chamber 32A is switched from a state in which heat is conducted with the outside air to a state in which heat is conducted with the inside air. In the second heat exchange section 30B, the state in which the inside of the second chamber 32B is heat-conducted with the inside air is switched to the state in which heat is conducted with the outside air. As a result, the temperature of the first heat exchange section 30A changes from _T3 to _T4 , and the temperature of the second heat exchange section 30B changes from _T1 to _T2 . The state shown in FIG. 6A is obtained by switching the operation mode.

As described above, in the control of the heat exchange device 10, the operation modes of the pair of heat exchange units 30A and 30B are alternately swing operated by repeating the operations shown in FIGS. 6A to 6H. As a result, cold heat can be continuously generated by the latent heat of vaporization Q _L [J] in the heat exchange units 30A and 30B in the desorption mode.

FIG. 7 shows the configuration of a general adsorption heat exchange apparatus relating to contrast. States 1 to 4 in FIG. 7 correspond to states 1 to 4 in FIG.

As shown in FIG. 7, the comparative heat exchange device includes an evaporator that heats and vaporizes the refrigerant under reduced pressure, an adsorber that desorbs and adsorbs the vaporized refrigerant, and an adsorber that desorbs and adsorbs the vaporized refrigerant. It has a condenser that condenses. In the heat exchange device according to the contrast, the latent heat of vaporization Q _L [J] in the evaporator is used for cooling. When the refrigerant is desorbed/adsorbed by the adsorbent, no latent heat is generated because the refrigerant remains gaseous (water vapor) without undergoing a phase change. Desorption/adsorption has been used to transport refrigerants. Since the heat exchange device according to the contrast utilizes the latent heat of vaporization in the evaporator for cooling, a large amount of energy is required for decompression and heating in the evaporator. Energy is also required for heating to regenerate the adsorbent that has adsorbed the medium. As a result, the coefficient of performance COP is lowered.

On the other hand, the heat exchange device 10 according to the present embodiment applies a stress to the nanoporous body 20 to change the phase of the refrigerant 63 to convert the latent heat of vaporization (desorption heat) Q _L [J] into cold heat. use. In addition, when the refrigerant 63 is desorbed from the nanoporous body 20, heating for regenerating the adsorbent and decompression and heating by an evaporator are unnecessary, so the energy required for desorption can be reduced. can. As a result, the coefficient of performance COP can be improved, so the amount of the nanoporous body 20 to be used can be reduced. Since an evaporator and a condenser are not required and the amount of the nanoporous body 20 can be reduced, the size of the heat exchange device 10 can be reduced.

<How to calculate the coefficient of performance COP>
Next, a method of calculating the coefficient of performance COP of the heat exchange device 10 according to this embodiment will be described.

The heat exchange device 10 according to the present embodiment desorbs the refrigerant 63 from the nanoporous body 20 by work W _ns [J] from the outside, and uses the obtained latent heat of vaporization Q _L [J] as cold heat. . As described above, in states 3 to 4 of the thermal cycle shown in FIG. 5, thermal energy loss occurs due to sensible heat Q _sh [J]. Therefore, in calculating the coefficient of performance COP, it is necessary to subtract the sensible heat Q _sh [J] from the latent heat of vaporization Q _L [J]. In addition, since the nanoporous body 20 is not a perfect elastic body, it is necessary to subtract the loss due to the internal friction Q _f [J] of the nanoporous body 20 . Therefore, the coefficient of performance COP of the heat exchange device 10 is given by the following equation.

The state 3→4 process is overall isobaric. Therefore, the sensible heat Q _sh is obtained by the following formula using the specific heat c _re [Jkg ^-1 K ^-1 ] of the liquid refrigerant 60 and the specific heat c _ns [Jkg ^-1 K ^-1 ] of the nanoporous body 20 can be represented.

Here, w _ns [kg] is the weight of the nanoporous body 20, and w _re-ads [kg] is the amount of refrigerant 60 adsorbed to the nanoporous body 20 at temperature T _H . This is the sum of refrigerant 61 and refrigerant 63 . The temperature T _H corresponds to the temperature inside the chambers 32A and 32B in the adsorption mode, and the temperature T _L corresponds to the temperature inside the chambers 32A and 32B in the desorption mode. In the adsorption mode chambers 32A and 32B, the amount of vapor of the refrigerant 60 is small, and the effect of the sensible heat is extremely small compared to _Qsh and can be ignored.

In State 4, the coolant 63 is adsorbed on the nanoporous body 20 in a liquid state. When mechanical stress is applied to the nanoporous body 20 to input work W ₂ [J], the adsorbed refrigerant 63 undergoes a phase change to saturated vapor (state 1). The process of state 4→1 is isobaric. Therefore, the latent heat of vaporization Q _L [J] can be expressed by the following equation.

Here, w _re [kg] is the amount of the refrigerant 60 detached from the nanoporous body 20 by stress application, and Δ _vap H is the enthalpy change when the refrigerant 60 undergoes a phase change from liquid to gas. However, w _re [kg] is the amount of the refrigerant 63 desorbed after opening the valve 51 of the pipe 50 connecting the first chamber 32A and the second chamber 32B. As described above, the latent heat of vaporization Q _L3-4 [J] generated by the desorption before the valve 51 is opened is used to offset the latent heat of condensation Q _H3-4 [J], so cold heat because it is not used.

The coefficient of performance COP in the reverse Carnot cycle of the present invention can be expressed by the following formula.

In Equation (5), W _ns [J] depends on the Young's modulus E [Pa] of the nanoporous body 20 . Here, the definition of Young's modulus E [Pa] is as follows.

Here, the stress σ _f [Pa] is the pressure (surface pressure) acting per unit area of the nanoporous body 20 . The strain ε _d is the maximum strain of the nanoporous body 20 in the most compressed state when the coolant 60 is desorbed from the nanoporous body 20 . The definition of the stress σ _f [Pa] is as follows.

Here, F[N] is the pressure acting on the nanoporous body 20 . S [m ² ] is the cross-sectional area of the nanoporous body 20 . The definition of the strain ε _d is as follows.

Here, x [m] is the amount of deformation of the nanoporous body 20 . L ₀ [m] is the length of the nanoporous body 20 in its initial state.

Assuming that the Young's modulus E [Pa] in the state containing the refrigerant 60 does not change, W _ns can be expressed by the following equation.

Here, V ₀ [m ³ ] is the initial volume of the nanoporous body 20 . Therefore, it can be transformed into the following formula.

Equation (10) is the formula for calculating the coefficient of performance COP of the present invention. In formula (10), w _re , w _re-ads , and V ₀ can each be represented by the weight w _ns of the nanoporous body 20 . In state 3, w _re-ads can be expressed using w _ns as follows.

Here, ρ _re [kgm ^-3 ] is the density of the refrigerant (liquid) 60, V _ns [m ³ kg ^-1 ] is the pore volume of the nanoporous body 20, and φ _ns is the filled volume of the refrigerant 60. is the ratio of pore volume to _Vns . That is, φ _ns V _ns corresponds to the volume of the pores filled with the coolant 60 or the volume of the coolant 60 filled in the pores. ρ _re φ _ns V _ns can be determined directly from the adsorption isotherm at temperature T _H .

V ₀ can be expressed by the following formula using the apparent density ρ _ns-ap [kgm ⁻³ ] of the nanoporous body 20 and the weight w _ns [kg] of the nanoporous body 20 .

At an arbitrary operating pressure P [kPa] with a temperature T _H , the nanoporous body 20 in the non-stressed state adsorbs w _non-TH [kg] of refrigerant 60 . This corresponds to state 3 in FIG.

Next, the temperature of the heat exchange section 30A is switched from _T3 to _T4 , and the temperature of the heat exchange section 30B is switched from _T1 to _T2 . At this time, the valve 51 between the chambers 32A and 32B is closed to prevent the vapor of the refrigerant 60 from moving from the chambers 32B to 32A. When the temperature of the heat exchange section 30A decreases from _T3 to _T4 , the gas phase refrigerant 62 is adsorbed on the nanoporous body 20, generating latent heat of condensation _QH3-4 and reducing the pressure of the gas phase. . Subsequently, stress is applied to the nanoporous body 20 to input work W ₁ [J] and desorb the coolant 62 . Then, latent heat of vaporization _QL3-4 is generated and the pressure of the gas phase increases, resulting in state 4. At this time, the amount of refrigerant 60 adsorbed on nanoporous body 20 is w _non-T3 [kg].

Next, stress is applied to the nanoporous body 20 to compress it, and the refrigerant 63 is desorbed. This corresponds to states 4 to 1 in FIG. In the nanoporous body 20 after maximum compression at temperature T ₄ (=T ₁ ), refrigerant 60 of w _press−T1 [kg] remains and is adsorbed (state 1). Therefore, the desorption amount w _4-1 [kg] of refrigerant 60 in the desorption mode can be expressed by the following equation.

Next, the temperature of the heat exchange section 30A is switched from _T1 to _T2 (= _T3 ), and the temperature of the heat exchange section 30B is switched from _T3 to _T4 (= _T1 ). At this time, the valve 51 between the chambers 32A and 32B is closed to prevent the vapor of the refrigerant 60 from moving from the chambers 32A to 32B. When the temperature of the heat exchange portion 30A rises from _T1 to _T2 , the refrigerant 62 adsorbed to the nanoporous body 20 is desorbed, generating latent heat of vaporization and increasing the pressure of the gas phase. Subsequently, the nanoporous body 20 is allowed to expand freely to adsorb the coolant 62 . As a result, the latent heat of condensation is generated and the pressure of the gas phase decreases, resulting in state 2. At this time, the nanoporous body 20 adsorbs the refrigerant 60 in the amount of w _press-T1 . Therefore, the adsorption amount w _2-3 [kg] of the refrigerant 60 in the adsorption mode is given by the following equation.

w _non-TH , w _press-TL, w _press-TH can be obtained from the adsorption isotherms shown in FIG. 13 at T _L , T _H uncompressed and under compression. Here, assuming that the adsorption amount of the refrigerant to the nanoporous body 20 does not change in T _L and T _H and is simply determined by the pore volume, w _re-ads =w _non-TL =w _{non −TH} , w _press =w _press−TL =w _press−TH , so that w _re =w _4-1 =w _2-3 and simplified calculation as shown in equation (15) is possible. Under this assumption, it is possible to derive the relationship between COP and E as shown below. It should be noted that the operating pressure P [kPa] of this system can be selected to any value so as to achieve a high coefficient of performance COP.

In the desorption mode, the pore volume of the nanoporous material 20 changes from V _ns to V _com [m ³ kg ^-1 ] when the nanoporous material 20 is compressed and subjected to a strain of _εd . . On the other hand, the volume occupied by the pore walls (1/ρ _ns ) does not change. Here, ρ _ns [kgm ⁻³ ] means the true density of the nanoporous body 20, that is, the density of the solid portion. Therefore, V _com becomes the following formula.

Since w _4-1 and w _2-3 are equal, w _re can be approximated as follows.

By the way, the following relationship exists between the apparent density ρ _ns-ap [kgm ^-3 ] of the nanoporous body 20 and ρ _ns and V _ns .

Therefore, the formula (17) becomes the following formula.

From equations (10), (11), (12) and (19), it can be seen that the COP of the present system does not depend on the weight (w _ns ) of the nanoporous mass.

The effects of the heat exchange device 10 according to the present embodiment described above will be described.

The heat exchange device 10 according to the present embodiment includes a nanoporous body 20 that has elasticity, can contract to desorb a refrigerant (medium) 60, and can expand to adsorb a medium, and a nanoporous body 20 It has heat exchange parts 30A and 30B including stress application parts 31A and 31B that apply stress to the body 20 to contract it, and chambers 32A and 32B that accommodate the nanoporous body 20 therein. The heat exchange device 10 controls the operation of the stress applying units 31A and 31B, and changes the operation mode of the heat exchange unit by applying stress to the nanoporous body 20 to shrink the medium from the nanoporous body 20. It further has a control unit 40 for switching between a desorption mode for desorption and an adsorption mode for releasing the stress to expand the nanoporous body 20 to adsorb the refrigerant 60 to the nanoporous body 20 .

According to the heat exchange device 10, stress is applied and released to the nanoporous body 20 to contract and expand, thereby causing the nanoporous body 20 to desorb and adsorb the refrigerant 60, thereby generating latent heat due to a phase change. be able to. As a result, the latent heat generated by the desorption or adsorption of the refrigerant 60 can be directly used for cooling or heating, thus eliminating the need for an evaporator or condenser. In addition, since the evaporator and condenser do not require depressurization or heating/cooling in order to obtain latent heat, the energy required for the thermal cycle can be reduced. As a result, the coefficient of performance COP can be improved, so the amount of the nanoporous body 20 to be used can be reduced. In this way, an evaporator and a condenser are not required, and the amount of the nanoporous body 20 can be reduced, so that the heat exchange device 10 can be miniaturized. Since the heat exchange device 10 can be miniaturized, it can be suitably applied particularly to car air conditioners with limited installation space.

Further, the heat exchange device 10 according to the present embodiment includes a pair of heat exchange units 30A and 30B and a pair of chambers 32A and 32B of the pair of heat exchange units 30A and 30B. and further comprising: The control unit 40 alternately switches the operation mode of each of the heat exchange units 30A and 30B between the adsorption mode and the desorption mode. Thus, latent heat of vaporization is continuously generated by alternately switching between the adsorption mode and the desorption mode between the pair of heat exchange sections 30A and 30B. Thereby, cold heat can be obtained efficiently.

Moreover, the Young's modulus E of the nanoporous body 20 according to this embodiment is 1 GPa or less. Reducing the stress required to shrink the nanoporous structure and desorb the coolant 60 reduces the work W _ns [J] and thus increases the coefficient of performance COP.

Further, the coolant (medium) 60 according to this embodiment is water. By using water, which has a high latent heat of vaporization, as the refrigerant 60, the coefficient of performance COP can be increased.

Also, the BET specific surface area of the porous material forming the nanoporous body 20 according to this embodiment is in the range of 800 to 4200 m ² /g. The adsorption amount of the refrigerant 60 can be increased by using the nanoporous body 20 having a large surface area. Thereby, the usage amount of the nanoporous body 20 can be reduced.

Also, the nanoporous body 20 according to the present embodiment is formed of zeolite template carbon (ZTC) or graphene meso sponge (GMS). As a result, by applying and releasing stress to the nanoporous body 20 to contract and expand, the nanoporous body 20 can reliably desorb and adsorb the coolant 60 to generate latent heat due to phase change.

The present invention will be described in more detail below with reference to examples. However, the technical scope of the present invention is not limited only to the following examples.

[Example 1]
(Preparation of ZTC)
ZTC according to this example was synthesized with reference to Nishihara, H. et al., Chemistry-European Journal 15, 5355 (2009). Zeolite X (Union Showa, 13X) was placed in an electric furnace and heated to 873K in a stream of nitrogen. When the temperature reached 873 K, nitrogen was switched to 20 vol% acetylene and 80 vol% nitrogen, and chemical vapor deposition (CVD) was performed for 4 hours to deposit carbon in the zeolite X pores. Then the flow was switched to nitrogen only and the temperature was raised to 1123 K and held for 3 hours. After cooling the sample to room temperature, zeolite X was removed with hydrofluoric acid (47 wt%, Wako pure chemical industries) to obtain ZTC.

<Bulk modulus and elastic properties of ZTC>
An experiment was conducted to measure the bulk modulus of the ZTC prepared in Example 1 and confirm its elastic properties. As a comparative example, activated carbon (Shirasagi-P, Japan EnviroChemicals, Ltd.) was used.

(Measurement of bulk modulus)
For Example 1 and Comparative Example, a mercury isostatic test was performed to measure the stress-volume strain curve. The bulk modulus was calculated from the obtained stress-volume strain curve. The mercury isostatic test is a test to measure the relationship between compressive stress and pore volume by mercury intrusion method using a mercury porosimeter (Micromerit-ics Instrument Corporation, Autopore IV 9510) under an isostatic press. . Specifically, the samples of Example 1 and Comparative Example, which had been vacuum-treated in advance, were set in a sealed chamber, and mercury was introduced into the chamber under vacuum. The volume V _Hg [m ³ ] when mercury spreads over the entire sample under stress (isotropic pressure) P [MPa] was measured. FIG. 8 shows the relationship between the stress P [MPa] and the pore volume strain V _Hg /V ₀ .

As shown in FIG. 8, at a stress of 20 MPa or less, _VHg drops sharply due to penetration of mercury into the intergranular spaces. The bulk elastic modulus K [MPa] of the sample was calculated from the linear approximation of the stress-volume strain curve when the stress was 50 to 150 MPa. A linear approximation formula can be expressed by the following formula.

where V ₀ [m ³ ] is the initial pore volume.

Assuming that the phenomenon occurring at 50 MPa or higher is deformation of pores due to mechanical compression, the bulk modulus was calculated from the above linear approximation formula. The bulk modulus of ZTC of Example 1 was 0.70 GPa. The bulk modulus of the activated carbon of the comparative example was 1.7 GPa. In the case of activated carbon, it may be underestimated because it has large pores.

Assuming that ZTC is an isotropic homogeneous elastic body, the relationship between bulk modulus K [MPa] and Young's modulus E [Pa] can be expressed by the following equation.

(elastic properties)
The ZTC single particles prepared in Example 1 and the activated carbon single particles according to the comparative example were used as samples. FIG. 9 shows the results of observing the change in shape when compressive stress was applied to the sample and then released. Specifically, the sample was placed on an aluminum substrate, compressed with a tungsten probe in the SEM apparatus, and the deformation of single particles was observed in situ. Subsequently, the probe was separated from the particle, and the restoration of the single particle was observed.

The shapes of ZTC particles and activated carbon particles were observed by SEM (Hitachi, S-4800). SEM (AD Science, PS4-2MM2LC-TH) was used for in situ observation of particle deformation due to stress application to single particles. The tip of the tungsten probe (GGB Industries, PT-14-6705-B) was previously cut vertically and flattened using a Ga-focused ion beam apparatus (FEI, Helios NanoLab 600i).

As shown in FIG. 9, it was confirmed that the ZTC was reversibly deformed by application of compressive stress (compressed by about 30%) and release. On the other hand, activated carbon was easily destroyed by similar compression and did not show reversible shape change.

<Measurement of desorption and adsorption of water under stress application>
An experiment was conducted to confirm the desorption and adsorption of water when stress was applied to the ZTC prepared in Example 1. FIG. 10 shows a press chamber apparatus for measuring the amount of desorption and adsorption of water when stress is applied or released to a sample in a closed chamber. A linear introduction device is connected to the chamber of the press chamber device, and is configured so that stress can be applied to the sample within the closed chamber.

First, the ZTC particles prepared in Example 1 were mixed with 5 wt % of Teflon (registered trademark) binder to form a sheet-like sample. The sample was vacuum dried at 423K and set in the chamber for in situ measurement of the press chamber apparatus. The chamber was fastened to an automatic gas adsorption apparatus (BEL Japan, BELSORB-max) so that the internal pressure of the chamber could be monitored. In order to secure a sufficient amount of sample for measurement, a sheet-like sample was sandwiched between stainless metal plates and set in the chamber in a laminated manner. Prior to in situ measurements, the laminated sample was pressed several times to stabilize the elastic deformation of the sample.

The relationship between the torque of the linear introducer and the stress applied to the stacked samples was previously confirmed by another experiment described below. A ratchet (Kyoto Tool Co., GEK085-W36) attached with a torque sensor was attached to the linear feeder so that the torque for rotating the linear feeder could be measured. With the tip of the linear introducer fixed so as to be in contact with the load cell of the testing machine (Shimadzu, AG-50kNXplus), the ratchet was turned to examine the relationship between the torque of turning the handle and the stress applied to the load cell. Using the above relationship, the stress applied to the laminated sample was controlled by the torque of the linear introducer.

FIG. 11 shows the measurement results of the desorption/adsorption isotherms of water at 298 K under applied stress and unstressed conditions for the ZTC of Example 1 and the activated carbon of Comparative Example. Here, the stress applied to the ZTC of Example 1 was set at 83 MPa, and the stress applied to the activated carbon of the comparative example was set at 120 MPa.

From the results of FIG. 11, at a relative pressure of P/P ₀ =0.94 (P: water vapor pressure, P ₀ : saturated water vapor pressure), in the stress applied state of 83 MPa in Example 1, water It was confirmed that the adsorption amount of was reduced by about 31%. This is believed to be due to the 31% reduction in pore volume due to the deformation of ZTC. The pores of ZTC exist in the gaps of graphene periodically arranged at intervals of 1.4 nm. When ZTC deforms, the pore size decreases, but the graphene thickness remains unchanged. Therefore, if the pores shrink by 31%, it can be estimated that the overall ZTC is strained by 23%. On the other hand, with respect to the activated carbon of the comparative example, no change was observed in the adsorption amount even in the stress-applied state of 120 MPa compared to the stress-unapplied state. This result is due to the lack of flexibility of activated carbon.

<Confirmation of Desorption/Adsorption of Water and Phase Change>
Next, experiments were conducted to confirm that desorption/adsorption of water and phase change of water (liquid)/water vapor occur by applying/releasing stress to the ZTC of Example 1. First, water vapor (relative pressure P/P ₀ =0.69) was introduced into the chamber at 298 K in which the ZTC of Example 1 was placed under no stress. After the pressure was no longer reduced and equilibrium was reached, a stress of up to 80 MPa was applied to the ZTC to desorb water vapor, and the pressure in the chamber was monitored. After 10 minutes, the stress was released and the ZTC was allowed to expand freely for 10 minutes. Four stress application/release cycles were performed. FIG. 12 shows the results of measurement of changes in water vapor pressure in the chamber when stress application and release were repeated. The dead volume reduction due to stress application was found to be 0.13 cm ³ , only 0.2% of the total volume (59 cm ³ ). This is only a 0.0014 increase in relative pressure P/ _P0 . Therefore, the increase in relative pressure P/P ₀ observed in FIG. 12 (approximately 0.09) is believed to be due to water vapor generated by forced desorption of adsorbed water by mechanical pressing.

Subsequently, a test was conducted in which the adsorbed water undergoes a phase change to water vapor due to mechanical stress. Water vapor was introduced into the chamber in advance, and the water vapor was adsorbed on the ZTC at a relative pressure of P/P ₀ =0.69. Subsequently, when a stress of 83 MPa was applied to the ZTC sheet, the water vapor pressure in the chamber increased to 0.79 ((i) in FIG. 12). It has already been confirmed that the reduction in dead volume caused by this compression is so small that it can be ignored.

Subsequently, when the stress was released, the water vapor pressure decreased ((ii) in FIG. 12), but this meant that the ZTC was free to expand back to its original shape, the vacancies were restored, and water vapor was adsorbed again. It indicates that

It was also revealed that water can be reversibly desorbed/adsorbed by applying/releasing stress ((iii) in FIG. 12). From this result, it was confirmed that the phase transition of water/water vapor due to stress application/release is reversible, and that ZTC can be applied as the nanoporous body 20 according to the present invention.

<Relationship between physical adsorption amount of ZTC and temperature>
FIG. 13 shows two water adsorption isotherms measured at 298 K (T _L ) and 303 K (T _H ) for the ZTC of Example 1, and the adsorption isotherm when ZTC is compressed at 83 MPa at these two temperatures. FIG. 11 shows a line projection; Point I in FIG. 13 is the water adsorption isotherm of unstressed ZTC measured at 298K. Point IV in FIG. 13 is the water adsorption isotherm of unstressed ZTC measured at 303K.

Point II and point III are values obtained by correcting the measured values of the water adsorption isotherms of points I and IV to 69% to reproduce the water adsorption isotherm under a stress of 83 MPa. Point II in FIG. 13 is the water adsorption isotherm of ZTC under stress of 83 MPa at 298K. Point III in FIG. 13 is the water adsorption isotherm of ZTC under stress of 83 MPa at 303K. It should be noted that, at a water vapor pressure of 2.9 kPa, the fact that the adsorption amount of ZTC in the stress-applied state of 83 MPa is reduced to 69% of the adsorption amount in the stress-free state indicates that the desorption/adsorption of water under stress application shown in FIG. This was confirmed from the isotherm measurement results.

<Calculation of coefficient of performance COP>
The water adsorption isotherm in FIG. 13 and the calculation formula for the coefficient of performance COP shown above (formula (10)), formula (11), formula (12), formula (13), formula (17) and formula (19) was used to calculate the value of the coefficient of performance COP when the heat exchanger 10 is operated with the ZTC as the nanoporous body 20 .

The operating conditions were T _H =303 K, T _L =298 K, and P=2.9 kPa. Also, it is assumed that a stress of 83 MPa is applied to the ZTC.

FIG. 14 shows the measurement results of the stress-strain curve obtained using the ZTC/PTFE sheet. Using this data, the COP at water vapor pressure of 2.9 kPa can be calculated based on equation (10).

In this equation, Δ _vap H = 2453 kJkg ^-1 and c _re = 4.184 kJkg ^-1 K ^-1 respectively. The temperature difference between the hot side and the cold side (T _H −T _L ) is 5K. c _ns was set to 0.72 kJkg ^-1 K ^-1 using the value of graphite. From equation (12), V ₀ =w _ns /ρ _ns-ap =0.001976w _ns . Furthermore, the Young's modulus of the ZTC sheet is determined to be 0.38 GPa from the stress-strain curve separately measured during the in situ measurement of FIG. Therefore, the strain _εd when 83 MPa is applied is 0.23. w _re-ads can be represented by w _ns , and is the adsorption amount of the nanoporous body 20 in the stress-free state at temperature T _H =303 K shown in point I (51.1 mmolg ⁻¹ =0.92 kgkg ⁻¹ ). From w _ns , w _re-ads =0.92w _ns .

As shown in equation (15), w _re is the difference between w _re-ads and w _press-TL . w _press-TL is expressed as 0.77w _ns from the adsorption amount of the compressed ZTC sheet (42.8mmolg ⁻¹ =0.77kgkg ⁻¹ )w _ns at temperature T _L =298K shown in point II of FIG. can be done. Therefore, w _re =0.92w _ns -0.77w _ns =0.15w _ns .

From the area of the hatched portion in FIG. 14, the energy loss φ _f [J] due to internal friction of the ZTC can be calculated to be 0.34. Since the energy loss becomes heat and raises the temperature of the room to be cooled, the loss is subtracted. The COP at T _H =303 K, T _L =298 K, and P=2.9 kPa can be obtained by substituting the numerical values shown above into equation (10), and is calculated to be 17.2.

Subsequently, the approximate relationship between the coefficient of performance COP and the strain _εd is calculated. In equation (10), assume that Δ _vap H=2453 kJkg ⁻¹ , c _re =4.184 kJkg ⁻¹ K ⁻¹ , T ₃ −T ₄ =20K. The value of c _ns can be assumed to be 0.72 kJkg ⁻¹ K ⁻¹ for graphite. Therefore, equation (10) can be expressed by the following equation.

Substituting equations (11), (12), and (19) yields the following equations.

In equation (21), ρ _re , φ _ns and V _ns can be determined from the adsorption isotherm at temperature T ₃ (see point IV in FIG. 13). ρ _re is 1000 kgm ⁻³ and ρ _ns-ap is at most about 1000 kgm ⁻³ for typical microporous materials. V _ns is about 0.003 m ³ kg ⁻¹ at most. Assume that φ _ns is 1. From the above, the coefficient of performance COP can be approximated by Equation (24) using Young's modulus E and strain _εd .

FIG. 15 is a diagram showing an approximation curve between the coefficient of performance COP of the heat exchange device 10 obtained by Equation (24) and the Young's modulus E depending on the strain amount ε _d of the nanoporous body 20 . The fitted curve was calculated using equation (24) above. As the strain ε _d becomes smaller, the coefficient of performance COP becomes larger _. As a result, the size of the heat exchange device 10 is increased. Therefore, the strain ε _d is preferably 0.2 or less. As shown in FIG. 15, the Young's modulus E of the nanoporous body 20 must be 1.1 GPa or less in order to make the coefficient of performance COP 10 or more under the condition that the strain ε _d is 0.2 or less. For the above reasons, the Young's modulus E of the nanoporous body 20 is preferably designed to be 1.1 GPa or less.

[Example 2]
Example 2 shows an example in which GMS is used as the nanoporous body 20 in the heat exchange device 10 and ethanol is used as the refrigerant 60 .

(Preparation of GMS)
GMS has a monolayer graphene framework and has large porosity and elasticity. For the GMS synthesis method, Advanced Functional Materials, Vol. 26, 2016, 6418-6427.

Alumina nanoparticles (Taimei Chemicals, TM300) were placed in an electric furnace and heated to 1173 K in a nitrogen stream. When the temperature reached 1173 K, the nitrogen gas was switched to 20 vol% methane and 80 vol% nitrogen, and carbon was deposited on the surfaces of the alumina nanoparticles by CVD for 2 hours. After that, the flow was switched to nitrogen only and cooled to room temperature. The obtained carbon-coated alumina nanoparticles were immersed in hydrofluoric acid (47 wt %, Wako pure chemical industries) to remove the alumina nanoparticles. The obtained mesoporous carbon was sintered at 2073K in an argon stream (10 Pa) to obtain GMS.

GMS consists mainly of monolayer graphene and has great elasticity. FIG. 16 shows the ethanol desorption/adsorption curves of GMS under no stress and under stress of 90 MPa (298 K). The adsorption amount at P/P ₀ =0.92 decreased to 58% with the application of stress. Assuming that the true density of GMS is 2.0 g/cm ³ for common carbon materials, the total pore volume is 2.79 cm ³ /g. Using these values, the deformation of the GMS as a whole is calculated to be 36%.

FIG. 17 shows the results of applying stress to the GMS during the measurement of the desorption/adsorption isotherm (298 K) of ethanol in the GMS. After the adsorption was completed, the desorption point shown at point A in FIG. 17 was observed, but when 90 MPa was applied to the GMS immediately after the measurement at point A was completed, point B was the next measurement point. That is, the relative pressure increased from point A to point B. From this result, it was confirmed that the heat exchange device 10 of Example 2 also undergoes a phase change (liquid to gas) when stress is applied. The above results show that GMS can also be applied as the nanoporous body 20 according to the present invention.

[Second embodiment]
FIG. 18 is a schematic cross-sectional view showing the configuration of the heat exchange device 100 according to the second embodiment. The stress-applying unit 200 of the heat exchange device 100 applies the repulsive stress due to the expansion of the nanoporous body of one heat exchange part in the adsorption mode to contract the nanoporous body of the other heat exchange part in the desorption mode. It is different from the first embodiment described above in that it has a stress converter 230 that converts stress. Since the configuration other than the stress applying section 200 is the same as that of the first embodiment described above, the same reference numerals are attached and the description thereof is omitted.

In the heat exchange device 10 according to the first embodiment, the two stress applying units 31A and 31B are attached to the two chambers 32A and 32B, respectively, and the two stress applying units 31A and 31B are controlled independently. A stress was applied and released to two nanoporous bodies 20A and 20B. In the heat exchange device 100 according to the second embodiment, one stress applying section 200 is attached to the two chambers 32A and 32B, and the one stress applying section 200 is controlled to produce two nanoporous bodies 20A and 20B. Apply and release stress on

The heat exchange device 100 performs swing operation such that while one of the pair of heat exchange units 30A and 30B is in the desorption mode, the other is in the adsorption mode. Therefore, when the heat exchange device 100 applies stress to the nanoporous bodies 20A, 20B in one chamber 32A, 32B to compress them, the nanoporous bodies 20A, 20B in the other chamber 32A, 32B Release stress to allow free expansion.

The first chamber 32A and the second chamber 32B are arranged symmetrically with respect to the center plane C. As shown in FIG. The configuration of the stress applying unit 200 will be described in detail below.

The stress applying section 200 includes a cylindrical cylinder 210, two pistons 220A and 220B movable in the cylinder 210, a stress conversion section 230 connecting the two pistons 220A and 220B, and press sections 240A and 240B. and The press portions 240A, 240B are fixed to each of the two pistons 220A, 220B to apply and release stress to the nanoporous bodies 20A, 20B.

The stress converter 230 has a first link member 231 rotating around the fixed axis O1, a second link member 232 connected to the piston 220A, and a third link member 233 connected to the piston 220B. The stress conversion portion 230 further has a connecting portion 234 that connects the first link member 231 , the second link member 232 and the third link member 233 . The fixed axis O1 is arranged on the central plane C. As shown in FIG. The connecting portion 234 has a movable axis O2 rotatable around the fixed axis O1.

One end of the first link member 231 is fixed to the fixed axis O1 so as to be rotatable around the fixed axis O1. The other end of the first link member 231 is connected to the connecting portion 234 so as to be rotatable around the movable axis O2.

One end of the second link member 232 is connected to the piston 220A so as to be rotatable around the first axis O3 fixed to the piston 220A. The other end of the second link member 232 is connected to the connecting portion 234 so as to be rotatable around the movable axis O2. Similarly, one end of the third link member 233 is connected to the piston 220B so as to be rotatable around the second axis O4 fixed to the piston 220B. The other end of the third link member 233 is connected to the connecting portion 234 so as to be rotatable around the movable axis O2.

19A to 19D are schematic cross-sectional views for explaining the operation of the heat exchange device 100 according to the second embodiment. Note that the operation of the stress applying unit 200 is controlled by the control unit 40 .

FIG. 19A is a diagram showing a state corresponding to FIGS. 6A, 6G, and 6H of the first embodiment. FIG. 19B is a diagram showing a state corresponding to FIG. 6B of the first embodiment. FIG. 19C is a diagram showing a state corresponding to FIGS. 6C, 6D, and 6E of the first embodiment. FIG. 19D is a diagram showing a state corresponding to FIG. 6F of the first embodiment. Since the operation modes of the heat exchange units 30A and 30B corresponding to each state are the same as those of the first embodiment, description thereof is omitted.

In FIG. 19A, the first nanoporous body 20A in the first chamber 32A is in a state of free expansion without application of stress from the stress applying section 200. In FIG. The second nanoporous body 20B in the second chamber 32B is in a contracted state due to the application of stress from the stress applying section 200. As shown in FIG. The distance L1 from the first axis O3 to the central plane C is shorter than the distance L2 from the second axis O4 to the central plane C.

When the first link member 231 is rotated counterclockwise about the fixed axis O1 from the state of FIG. 19A, the connecting portion 234 moves toward the first chamber 32A. As the connecting portion 234 moves, the second link member 232 and the third link member 233 move toward the first chamber 32A. As a result, the two pistons 220A, 220B move toward the first chamber 32A.

As the piston 220B moves, stress is gradually released from the second nanoporous body 20B in the second chamber 32B. As a result, the second nanoporous body 20B expands freely. The repulsive stress due to the free expansion of the second nanoporous body 20B is transmitted to the second link member 232 via the press portion 240B, the piston 220B and the third link member 233. The second link member 232 uses the repulsive stress as stress for compressing the first nanoporous body 20A in the first chamber 32A. That is, the stress converter 230 converts repulsive stress due to free expansion of the second nanoporous body 20B into mechanical energy W _rns [J] for compressing the first nanoporous body 20A.

When the first link member 231 is rotated 90 degrees counterclockwise about the fixed axis O1 from the state shown in FIG. 19A, the state shown in FIG. 19B is obtained. 19B, the movable axis O2 is arranged on the central plane C. In FIG. In this state, the distance L1 from the first axis O3 to the central plane C is equal to the distance L2 from the second axis O4 to the central plane C.

When the first link member 231 is further rotated 90 degrees counterclockwise about the fixed axis O1 from the state of FIG. 19B, the connecting portion 234 moves further toward the first chamber 32A and enters the state of FIG. 19C. The distance L1 from the first axis O3 to the central plane C is longer than the distance L2 from the second axis O4 to the central plane C. As a result, the first nanoporous body 20A in the first chamber 32A is in the most compressed state, and the second nanoporous body 20B in the second chamber 32B is in a stress-relieved state.

When the first link member 231 is further rotated counterclockwise about the fixed axis O1 from the state of FIG. 19C, the connecting portion 234 moves toward the second chamber 32B. 19A and 19B, the stress converter 230 converts the repulsive stress due to the free expansion of the first nanoporous body 20A to the mechanical energy W _rns [J ].

When the first link member 231 is rotated 90 degrees counterclockwise about the fixed axis O1 from the state shown in FIG. 19C, the state shown in FIG. 19D is obtained. 19D, the movable axis O2 is located on the central plane C. In FIG. In this state, the distance L1 from the first axis O3 to the central plane C is equal to the distance L2 from the second axis O4 to the central plane C.

As described above, in the control of the heat exchange device 100, the operation modes of the pair of heat exchange units 30A and 30B are alternately swing operated by repeating the operations shown in FIGS. 19A to 19D. As a result, cold heat can be continuously generated by the latent heat of vaporization Q _L [J] in the heat exchange units 30A and 30B in the desorption mode. In addition, the stress converter 230 can convert repulsive stress due to free expansion of the nanoporous bodies 20A and 20B into mechanical energy W _rns [J] for operating the heat exchange device 100 and recover it.

The base of the COP calculation formula is as shown in formula (5), but as shown in FIGS. can be recovered as recoverable mechanical energy W _rns [J], it can be subtracted from the applied energy, which is the denominator, and can be represented by Equation (25).

As shown in FIG. 20, the recoverable mechanical energy W _rns [J] associated with the repulsive stress due to the free expansion of the nanoporous bodies 20A and 20B when released is obtained from the hysteresis of the stress-strain curve of the nanoporous bodies. Obtainable. Also, the lost energy can be obtained by subtracting the amount lost due to the internal friction Q _f [J]. FIG. 20 shows the stress-strain curve of the nanoporous material measured under the same conditions as in FIG.

Substituting equation (28) into equation (25) yields:

By substituting into the formulas (3) to (9), the formula for calculating the COP of the system for recovering the repulsive stress becomes the formula shown in the formula (30).

In this equation, the same conditions as in Example 1, respectively Δ _vap H = 2453 kJkg ^-1 , c _re = 4.184 kJkg ^-1 K ^-1 , temperature difference between high temperature side and low temperature side (T _H - T _L ) = 5K , c _ns = 0.72 kJkg ^-1 K ^-1 , and the stress-strain curves (FIGS. 14 and 20) separately measured during the in situ measurement of FIG. is asked. Therefore, the strain ε _d when 83 MPa is applied is 0.23, and the adsorption amount of the nanoporous body 20 in the stress-free state at the temperature T _H = 303 K shown in point I (51.1 mmol g ^-1 = 0.92 kg kg ^{- 1} ) From w _ns , w _re-ads =0.92 w _ns , the adsorption amount of the compressed ZTC sheet at temperature T _L =298 K shown in point II (42.8 mmol g ⁻¹ =0.77 kg kg ⁻¹ )w _ns , from Since it is 0.77w _ns , w _re =0.92w _ns -0.77w _ns =0.15w _ns From the hatched area in FIG. 14, the energy loss φ _f [J] due to internal friction of ZTC is calculated. Substituting 0.34 for each, we can calculate the _{COP in} a system that recovers the repulsive stress under the conditions of FIG. It is improved from 17.2 of Example 1 to 50.6.

As described above, the stress applying section 200 of the heat exchange device 100 according to the present embodiment desorbs the repulsive stress due to the expansion of the nanoporous bodies 20A and 20B of the heat exchange sections 30A and 30B on one side in the adsorption mode. It further has a stress converting portion 230 that converts the stress for contracting the nanoporous bodies 20A, 20B of the heat exchanging portions 30A, 30B of the other mode. The stress converter 230 converts repulsive stress due to free expansion of one nanoporous bodies 20A and 20B into mechanical energy W _rns [J] for compressing the other nanoporous bodies 20A and 20B. As a result, the repulsive stress of the free expansion of the nanoporous bodies 20A and 20B can be recovered efficiently.

[Modification of Second Embodiment]
The configuration of the heat exchange device including the stress conversion section is not limited to the form shown in FIG. 18, and can be changed as appropriate. For example, in the form shown in FIG. 18, an example in which the stress conversion section and the chambers 32A and 32B are horizontally fastened is shown, but a system in which they are fastened in a V-shape as shown in FIG. 21 has the same effect.

18 and 21 show an example in which two chambers are combined, similar effects can be obtained by combining three chambers or, if necessary, four or more chambers.

Although the heat exchange device according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. Various modifications of the present invention are possible based on the configuration described in the claims, and these are also within the scope of the present invention.

For example, the case where the heat exchange device of the present invention is applied to a cooling device (chiller) that cools an object by utilizing the cold heat obtained from the latent heat of vaporization at the time of desorption has been described as an example. It may be applied to a heating device (heat pump) that heats an object using heat obtained from latent heat of condensation.

In addition, although the batch-type heat exchange device having a pair (two) heat exchange units has been described, it is not limited to this, and may be configured with one heat exchange unit, or with three or more heat exchange units. may be configured by

10, 100 heat exchange device,
20 nanoporous body,
20A first nanoporous body,
20B second nanoporous body,
30A first heat exchange section (heat exchange section),
31A first stress applying portion (stress applying portion),
32A first chamber (chamber),
30B second heat exchange section (heat exchange section),
31B second stress applying portion (stress applying portion),
32B second chamber (chamber),
33A first air conditioning unit,
33B second air conditioning unit,
40 control unit,
50 piping,
51 valve,
60 refrigerant (medium),
200 stress applying section,
210 cylinders,
220A, 220B pistons,
230 stress converter,
231 first link member,
232 second link member,
233 third link member,
234 connector,
240A, 240B Press section.

Claims (7)

a nanoporous body having elasticity, capable of desorbing a medium by contraction, and having a plurality of nano-level pores capable of adsorbing the medium by expansion;
a stress-applying unit that applies stress to the nanoporous body to shrink the pores ;
a chamber containing the nanoporous body;
a heat exchange section comprising
By controlling the operation of the stress-applying part, the operation mode in the heat exchange part is set to detach the medium from the pores by applying stress to the nanoporous body to shrink the pores . a control unit for switching between a mode and an adsorption mode in which stress is released to expand the pores to adsorb the medium to the pores ;
A heat exchange device. a pair of heat exchange parts;
a pipe that communicates between the chambers of the pair of heat exchange units so that the medium can move;
further having
2. The heat exchange device according to claim 1, wherein the control section alternately switches the operation mode of each of the heat exchange sections between the adsorption mode and the desorption mode. The stress-applying unit causes the repulsive stress due to the expansion of the nanoporous body of the one heat exchange part in the adsorption mode to contract the nanoporous body of the other heat exchange part in the desorption mode. 3. The heat exchange device according to claim 2, further comprising a stress converter that converts the stress of . The heat exchange device according to any one of claims 1 to 3, wherein the nanoporous body has a Young's modulus of 1.1 GPa or less. The heat exchange device according to any one of claims 1 to 4, wherein the medium is water. The heat exchange device according to any one of claims 1 to 5, wherein the BET specific surface area of the porous material forming the nanoporous body is in the range of 800 to 4100 m ² /g. The heat exchange device according to any one of claims 1 to 6, wherein the nanoporous body is formed by zeolite templated carbon (ZTC) or graphene mesosponges (GMS).

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