JP2019013125A - Mechanism for obtaining steady heat flow or steady power from time variation in environmental temperature - Google Patents

Abstract

To achieve formation of a heat transfer mechanism in a space or in one direction with a spontaneously steady temperature gradient in time-varying temperature fluctuations without using a large-scale mechanism for concurrently ensuring a high-temperature heat source and a low-temperature heat source, in an event in which energy conversion is executed using a temperature difference, such as temperature difference power generation.SOLUTION: A latent heat storage substance with two different phase transition temperatures or a chemical heat storage substance with two different reaction temperatures is arranged in a spatial manner and the two power storage substances make different temperature reactions at time-varying environmental temperatures, thereby achieving a system whose one side has a higher temperature than the other side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology that spontaneously generates a steady, spatially unidirectional heat flow from an environment in which the temperature fluctuates with time, such as waste heat from an engine, solar heat, or room temperature, and power generation utilizing the temperature difference. It is related to energy conversion technology.

  For engines and generators that convert thermal energy into mechanical energy or electrical energy, it is known as Carnot's theorem that the maximum conversion efficiency of thermal energy is determined by the difference in absolute temperature. Conventionally, fossil fuels such as oil have been used for cooling water or room temperature air as the low-temperature heat source, and the use of fossil fuels such as oil has been used, but waste heat is not fully utilized from the viewpoint of resource depletion and global warming countermeasures. It is expected to utilize the temperature difference caused by natural phenomena.

  In energy conversion utilizing the temperature difference, it is important not only to secure a high-temperature heat source but also to secure a low-temperature heat source. In the power generation technology using the waste heat of the incinerator shown in Patent Document 1, the exhaust gas generated in the incinerator is used as a high-temperature heat source, and cooling water or the like is used as a low-temperature heat source to generate power using the temperature difference between these heat sources. Similar energy conversion technology is also used for waste heat from automobile engines.

  As the power generation mechanism, a thermoelectric conversion element shown in Patent Document 2 or binary power generation shown in Patent Document 3 is used. The generated electric power can be applied in various ways such as light source and promotion of chemical reaction through energy conversion.

  These temperature difference power generations are premised on the existence of a high-temperature heat source and a low-temperature heat source at the same time. Moreover, it is preferable that the high temperature heat source and the low temperature heat source are spatially separated to ensure a temperature difference between them. That is, a device for avoiding a decrease in temperature difference due to heat transfer inside the conversion mechanism is used by using a heating mechanism and a cooling mechanism.

JP-A-2016-90129 JP 2006-74919 A JP 2014-194210 A

  Engines that generate waste heat and natural phenomena with heat often change over time. In addition, heat easily diffuses, and the temperature difference in the target space region tends to disappear. Therefore, in order to secure a high temperature heat source and a low temperature heat source at the same time in a narrow space region, a large-scale apparatus configuration is often required. If a compact mechanism that spontaneously generates a temperature difference even during temporal temperature fluctuations and enables power generation or the like can be realized, it can greatly contribute to resource problems and global warming problems.

  Thermal energy that is almost uniform over a wide range, such as indoor air temperature and wall temperature, and fluctuates in a relatively long time period, can be converted into usable electrical energy even if the total change is large. There wasn't.

  Therefore, in the present invention, a simple heat transfer mechanism that generates a temperature difference in one direction spatially and a steady heat flow from an environment in which the temperature fluctuates temporally even if the temperature is spatially uniform, and the heat transfer mechanism are utilized. Provide compact power generation technology.

  The present invention spatially arranges two latent heat storage materials having different phase transition temperatures or two chemical heat storage materials having different reaction temperatures, and the two latent heat storage materials have different temperature responses at temporally varying environmental temperatures. It is the most important feature that one of them is steadily higher in temperature than the other by utilizing the above, and that this temperature difference is utilized for power generation or the like.

  The above two latent heat storage materials or chemical heat storage materials have different intrinsic phase transition temperatures or reaction temperatures and have the property of maintaining the phase transition or reaction. When these two are exposed to the same fluctuating external environmental temperature, one is higher than the target environmental temperature fluctuation average temperature and lower than the maximum temperature, and the other is lower than the average environmental fluctuation temperature and higher than the minimum temperature It is necessary. If there is a difference between the two touching external environment temperatures, each may be set to the average temperature of the external environment that performs heat exchange. Hereinafter, the latent heat storage material and the chemical heat storage material are collectively referred to as a heat storage material, and the phase transition temperature or reaction temperature specific to the material is collectively referred to as a specific temperature.

  The thermal coupling between the internal space and the external environment that will cause a temperature difference is realized via only two heat storage materials as much as possible. That is, the internal space and the two heat storage materials are in contact with two different heat transfer surfaces, and the heat transfer surfaces other than the heat transfer surface are configured with heat insulating walls so that the two heat transfer surfaces do not directly touch each other. A sufficient amount of the heat storage material is used so that it can maintain the vicinity of the natural temperature within the temporal fluctuation cycle of the external environment temperature.

  When the heat storage material is poor in heat conductivity, a heat energy flow path that forms a composite material of a material having high heat conductivity and a heat storage material and moves between the outside and the internal space is used.

  Since the internal space realized in this manner constantly generates a temperature difference due to the two heat storage materials, it is possible to perform power generation and binary power generation using the thermoelectric conversion element by utilizing this temperature difference.

  In addition to using a sufficient amount of heat storage material, the boundary between the heat storage material and the external environment will be used as a means of preventing the internal temperature difference from disappearing because the thermal exchange between the external environment and the heat storage material is dominant over the internal heat conduction. It is effective to introduce a thermal rectification mechanism on the surface. At this time, the rectification direction is determined so that the internal heat flow direction and the directivity of heat flowing in and out from the outside coincide.

  According to the present invention, a steady temperature gradient can be generated spontaneously from an external environment in which the temperature fluctuates with time. Furthermore, using this temperature difference, it is possible to realize temperature difference power generation and a power source with a simple, compact and inexpensive configuration. Since it also has a heat storage and temperature maintenance effect, it can be used for housing walls, furniture, etc. to generate electricity while voluntarily adjusting the indoor temperature. It can also be used as a temperature rise prevention means for computer CPUs, etc., leading to power savings. It can also be used for the effective use of energy by applying it to portable power supplies, emergency power supplies for disaster prevention, etc., battery replacement, power supplies for communication in places where it is difficult to route wires, automobiles, furnaces, etc. It can be used as various on-site energy infrastructures such as hydrogen production, storage battery charging, and power supply for freshwater generation mechanism. Unlike solar power generation, which cannot generate power at night, it can be designed to generate power stably at all times.

It is a figure which shows the outline of the heat-transfer mechanism in embodiment of this invention. It is a figure of the composite material which disperse | distributed the thermal storage substance in the substance of high thermal conductivity. It is a figure of the composite material which disperse | distributed the substance of high thermal conductivity in the thermal storage substance. It is a figure which shows the temperature response of the thermal storage substance composite material at the time of a heating and cooling. It is a temperature graph of environmental temperature fluctuation | variation and two types of thermal storage material composite materials. It is a figure of the natural charge battery which is 1st embodiment. It is a figure of the electric power generation system by periodic thermal radiation which is 2nd embodiment. It is a figure of the electric power generation system using the fluctuating heat source in the third embodiment. It is a figure of the cascade type electric power generation mechanism in 4th embodiment.

  Hereinafter, description will be given with reference to the drawings.

As shown in FIG. 1, the heat transfer mechanism A of the present invention is separated from an internal space 4 separated by at least a heat storage material 2 (inherent temperature T _H ) and 3 (inherent temperature T _L ) having a specific temperature different from that of the heat insulating wall 1. Composed. If a heat transfer system is inserted into the internal space so as to be in thermal contact with the two heat storage materials, a heat flow Q flowing through the internal space is generated. If what is put in the internal space is an energy conversion device, a part of the thermal energy can be converted into other energy such as electric power.

The internal space 4 is thermally connected to the external environment through at least the heat storage materials 2 and 3 and the heat transfer surface 5. It is preferable to insert the heat rectifying mechanism 6 between the heat storage material 2 and the heat transfer surface 5 and between the heat storage material 3 and the heat transfer surface 5. At this time, the direction of thermal rectification on each heat transfer surface is made to coincide with the direction of the heat flow Q in the internal space from the higher specific temperature T _H to the lower specific temperature T _L.

  Hereinafter, a mechanism for generating a steady temperature gradient in the internal space and thus a steady heat flow Q from the time variation of the external environment temperature will be described. The following explanation is an example of a latent heat storage material, but the purpose is also realized by a similar mechanism when a chemical heat storage material is used.

   When the latent heat storage material is solid at a temperature lower than the phase transition temperature, and a certain heat flow flows into the latent heat storage material from a higher temperature external environment, there is a temperature gradient from the surface side in contact with the external environment to the internal space side. it can. The surface side that has reached the phase transition temperature eventually melts. The internal solid / liquid interface moves from the surface side to the internal side, and eventually the entire latent heat storage material melts and becomes liquid. On the contrary, the latent heat storage material becomes a solid higher than the phase transition temperature, and when heat flows out to the external environment, it becomes a solid from the surface side and the solid / liquid interface moves toward the inside.

  At this time, the temperature gradient from the outside to the inside and the moving speed of the solid / liquid interface are determined by the thermal conductivity of the latent heat storage material. In general, the latent heat storage material has low thermal conductivity, and the difference in temperature change between the surface and the inside tends to be remarkable.

  However, in the case where the latent heat storage material contained in the microcapsule is dispersed into a material having high thermal conductivity such as carbon or silver paste as shown in FIG. 2 to form a composite material, or carbon fiber or the like as shown in FIG. When a material having a high thermal conductivity is a composite material dispersed in the latent heat storage material, the temperature distribution inside and outside is made more uniform.

  When the initial state of the latent heat storage material composite material is solid, and when a constant heat flow is given from the external environment, the average temperature of the latent heat storage material composite material varies as shown in the left graph of FIG. The initial gradient is the temperature rise as a solid, and the temperature stagnation state is a solid-to-liquid phase transition that continues until it is completely melted. After complete melting, the temperature rises as a liquid.

  Conversely, when the solution-state latent heat storage material composite material is placed in an environment having a constant cooling rate, a change in which the left graph is reversed as shown in the right graph of FIG. 4 is shown. That is, the initial gradient indicating cooling as a liquid, a plateau indicating a phase transition from liquid to solid, and a cooling gradient as a solid change in this order.

  Thus, if the latent heat storage material is utilized, the temperature of the composite material can be kept constant during the phase transition. A plateau can be made at a desired temperature by appropriately selecting the proper temperature by changing the chemical structure and composition such as the molecular chain length of the latent heat storage material.

  When the latent heat storage material comes into contact with an external environment that periodically changes temperature, the latent heat storage material is solidified or liquefied. If the total amount of latent heat of the latent heat storage material is larger than the total amount of heat entering and exiting within the period, the plateau is maintained as the temperature of the entire latent heat storage composite material only by changing the ratio of liquid to solid in the phase transition state.

Therefore, as shown in FIG. 5, the external environment changes if the latent heat storage material has two kinds of intrinsic temperatures ( _TH and _TL ) that maintain the phase transition temperature with respect to the periodically changing external environment temperature. Even in this case, the high temperature T _H and the low temperature T _L can be constantly maintained inside the system. As shown in FIG. 1, since the internal space is in contact with a heat source having a predetermined temperature difference between T _H and the other T _L and the other, heat flow Q is generated in the internal space.

If the latent heat storage material is used so that it is constantly in the range of the phase transition state with respect to the sum of the periodic heat input and output of the latent heat storage material and the external environment and the heat flow Q in the internal space, the temperature difference ΔT = T _H and T _L and the heat flow Q are constantly constant. Even if heat exchange is performed exceeding the latent heat capacity, it is possible to create a temperature difference from the delay in response of the two latent heat storage materials to the external temperature. In the latter case, the temperature difference is smaller than ΔT.

As shown in FIG. 1, when the heat rectifying substance 6 is installed at the interface where the latent heat storage material contacts the external environment so that the direction of the heat flow Q coincides with the heat flow Q, the external environment fluctuates with an unexpected fluctuation width. Even in this case, the heat exchange between the latent heat storage material in the direction opposite to the heat flow Q and the external environment can be relatively restricted, and the internal heat flow Q can be easily maintained. When using a high T _H and a low T _L than the average of the temperature variation of the external environment, and the heating time when heat inflow occurs from specific temperature or more external environment experienced these latent heat storage material, specific temperature or less of the external environment In general, the cooling time flowing out into the is not equal. In order to always maintain the intrinsic temperature, it is desirable that melting and solidification change in an equal amount in one cycle, that is, balance between heat inflow and outflow. Therefore, introduction of thermal rectification is a more preferable configuration for this adjustment.

  The essence in the configuration of FIG. 1 is not the shape but the configuration. The internal space surrounded by the heat insulating wall has a heat transfer surface in contact with the two heat storage materials, and the internal space is responsible for heat transfer through the external environment and the heat storage material. There is flexibility in designing the hardness of the entire system and the positional relationship between the two heat transfer surfaces.

With the above mechanism, a steady temperature gradient, and thus a steady heat flow Q, is generated in the internal space from the time variation of the external environment temperature. In order to realize the purpose, the temperature of the external environment does not have to be completely periodic, but it needs to swing around the average temperature. T _H is determined between the average temperature and the upper limit of oscillation, and T _L is determined between the average temperature and the upper limit of oscillation. In a system where only the average monotonic rise or conversely monotonous decrease is achieved, the latent heat storage material is completely liquefied or solidified, and the phase transition temperature cannot be maintained. The difference ΔT disappears.

  The internal heat flow Q can be used for various applications such as power generation and charging that use thermal energy, energy conversion such as power source that uses thermal energy, or chemical reaction, sensing, and computation using the converted energy. It is. When the mechanism of the present invention is used not only for the power generation function but also for the wall of the room, etc., the temperature fluctuation of the room is suppressed by heat exchange with the external environment via a heat storage material, contributing to the reduction of energy consumption for temperature control. To do.

  In the following, the heat transfer mechanism for converting a temporal temperature fluctuation into a spatial temperature gradient and the components of the energy conversion mechanism utilizing the temperature difference or heat flow of the present invention will be described in detail.

  The heat insulating wall 1 can be made of polystyrene foam, glass wool, wool heat insulating material, a material having low thermal conductivity, or a vacuum heat insulating structure. However, the present invention is not limited to these, and any of those having heat insulation properties can be applied.

  The latent heat storage materials available for the heat storage materials 2 and 3 include organic compounds such as paraffin, fatty acid, sugar alcohol, inorganic hydrate salts such as calcium chloride hydrate and sodium sulfate hydrate, low melting point metals such as gallium, and Ice-water can be used near room temperature. At high temperatures, metals such as copper, alloys such as Al-Si, and salt-molten salt systems can be used. However, the present invention is not limited to these, and any of those having latent heat storage properties is applicable. The substance should be selected so that the melting point is within the temperature fluctuation range of the external environment.

Heat storage material 2 and chemical heat storage material available in 3 MgO + H2O → Mg (OH ) absorption reaction such as _2, FeCl ₃ · (mn), such as _{CH 3 OH + nCH 3 OH →} FeCl 3 · mCH 3 OH A hydration reaction such as a mixed reaction or Na ₂ S + 5H ₂ O → Na ₂ S · 5H ₂ O can be used. However, the present invention is not limited to these, and any of those having chemical heat storage properties can be applied. The substance is selected so that the reaction equilibrium temperature is within the temperature fluctuation range of the external environment.

  The mechanism for converting the heat energy introduced into the internal space 4 into electric energy is a thermoelectric conversion element using materials such as bismuth tellurium, lead / tellurium, silicon / germanium, and thermocouples such as copper, iron, chromel, water vapor, etc. Turbine power generation using, binary power generation using ammonia or the like can be used. Thermal energy may be converted into other energy such as mechanical energy and finally converted into electrical energy.

  A steam engine, a Stirling engine, or the like can be used as a mechanism for converting thermal energy introduced into the internal space 4 into mechanical energy. Thermal energy may be converted into other energy such as electric energy and finally converted into mechanical energy.

  Furthermore, conversion to light energy such as laser, conversion to chemical energy such as electrolysis and charging, and conversion to heat energy such as a heater are possible using the above-described electric energy and dynamic energy. These additional conversion mechanisms may close part of the internal space or other components, or may be external.

  The heat transfer surface 5 is an arbitrary solid having high thermal conductivity such as aluminum, sapphire, or carbon material, and a fluid material having excellent thermal conductivity such as silver paste, or a convection fluid or an easily evaporating liquid therein. It has a structure with excellent heat transportability. The heat transfer surface may be thermally exchanged with the external environment by heat radiation, in which case the heat transfer surface is close to a black body (especially in the infrared and far-infrared regions where the emissivity is close to 1 or a porous structure) Those having an emissivity close to 1 in a wide wavelength range are preferred.

  The heat transfer surface may be thermally connected through an external environment or a cover of the main body structure, or may be separated. As an example of the former, there are cases where two heat transfer surfaces form part of the same metal container and utilize the temperature fluctuation of the outside air for a day. As an example of the latter, one heat transfer surface faces the incinerator and its heat radiation, and the other heat transfer surface faces the outside air that does not directly receive the heat radiation of the incinerator. There is a case where heat is exchanged with the outside air which fluctuates with a cycle.

Various materials are known as the preferred heat rectifying material 6 when placed between the heat transfer surface and the heat storage material. For example, the contact structure of two substances that have roughness on the contact surface and the degree of thermal contact changes depending on the heat transfer direction, the strain and pressure change depending on the temperature gradient direction, and the heat transfer performance of the contact surface becomes uneven. Bonding structure of two materials, temperature dependence of thermal conductivity such as graphite / quartz, etc., so that there is a difference in total heat conduction depending on the heat transfer direction, insulating material such as Cu / Cu ₂ O Two joint structures with asymmetric distribution of heat transfer carriers in body joints, structures where metals with different work functions such as aluminum and iron are in contact via an insulator such as an oxide film, carbon and carbon nanotubes Various materials systems or mechanisms, such as structures that are distributed asymmetrically with respect to the direction of heat conduction, systems in which emissivity is exchanged by heat radiation through materials close to black bodies in vacuum And the like hardly structure transmitted from top to bottom but easily transmitted from bottom to top by the buoyancy heat transfer system using. However, the present invention is not limited to these, and any of those in which thermal rectification is recognized in the temperature fluctuation range of the target external environment can be applied.

  Hereinafter, the natural charging battery B which is the first embodiment will be described.

As shown in FIG. 6, a plate-shaped natural rechargeable battery B can be created. A charging circuit 11 for charging the battery 10 with electric power from the thermoelectric conversion element 9 is included inside, and the storage battery is charged naturally in the temperature fluctuation. The output from the storage battery is taken out from the terminal 12. The storage battery and the charging circuit are housed in a heat-insulating container so as not to be a heat transfer path. Used as paraffin heat storage material to operate at near room temperature, the melting point of T _H and T _L is adjusted by the molecular weight.

  The natural rechargeable battery B can be a sensor, a communication power source thereof, or an electronic device such as a portable mobile phone. A large number of them can be combined into a larger plate shape and incorporated in the wall surface of a house or the like. When used for a wall surface, not only power generation but also a heat storage material has an effect of relaxing indoor temperature fluctuations.

  Next, the power generation system C using periodic heat radiation according to the second embodiment will be described.

  As shown by the arrows in FIG. 7, it is possible to construct a power generation system that operates by heat radiation directed in one direction that varies periodically, such as sunlight or a furnace that operates intermittently. At this time, since the heat transfer surface 5 is a light receiving / dissipating surface, it is preferable to use a substance having a high emissivity (and thus a high absorption rate) as the heat transfer surface. Stable power can be obtained by arranging the power generation structures on the wall. The technology can also be used for spinning spacecraft and extraterrestrial structures that are periodically exposed to sunlight. By rotating the composition having a surface on which the power generation system is arranged with respect to thermal radiation, it is possible to utilize the system so as to stably generate power while reducing the thermal load. In order to clearly show the two output cables of the thermoelectric conversion element 9 to the outside of the system, the heat insulating wall is depicted as partly interrupted, but all the heat transfer surfaces are surrounded by the heat insulating wall. desirable. The same applies to the subsequent drawings.

  Next, a power generation system D that uses a variable heat source that is distant from each other according to the third embodiment will be described.

  The ceiling of buildings illuminated by sunlight tends to be higher than indoors. In addition, since warmed air rises, the upper floor tends to be hotter. On the wall of the blast furnace, the temperature decreases from the inner wall toward the outer side. Thus, it is widely seen that a change in one thermal environment results in two fluctuating heat sources that occur at two positions that are separated from each other. FIG. 8 shows the application of the present invention in this environment.

As shown in FIG. 8, a temperature gradient is caused in the object 13 affected by a certain heat source. The two distant points become heat sources with different temperatures. Similar to the structure described so far, the temperature difference T _H of the internal space and the heat transfer mechanism 14 such as a heat pipe or a heat exchanger for transmitting the latent heat storage material or its temperature to the high temperature heat source and the low temperature heat source, respectively. _TL is generated. It is the same that a stable temperature gradient can be created and energy conversion can be performed in an environment where the original heat source fluctuates.

  Next, a cascade type power generation mechanism E which is a fourth embodiment will be described.

As shown in FIG. 9, the heat transfer mechanism and the energy conversion mechanism of the present invention can be not only arrayed in the plane direction but also stacked in the heat transfer direction to form a cascade structure. That, T _H of a certain hierarchy is the T _L of the next layer. Thereby, it is possible to utilize energy without waste over a wide temperature range.

  Although the embodiments of the present invention have been described in detail above, it should be understood that modifications, variations, and changes can be made without departing from the scope of the claims.

From the heat storage material 3 is a specific temperature of the hot from A heat transfer mechanism body B natural rechargeable battery C periodic power system E cascaded power generating mechanism using a change heat source away generator system D by heat radiation 1 insulating wall 2 (T _H) Thermal storage material that is a low temperature ( _TL ) intrinsic temperature 4 Internal space 5 Heat transfer surface 6 Thermal rectification mechanism 7 Thermal storage material 8 Material with high thermal conductivity 9 Thermoelectric conversion element 10 Storage battery 11 Charging circuit 12 Output terminal 13 from battery An object affected by a heat source 14 Heat transfer mechanism

Claims (4)

  Even if there is a spatial distribution, an internal space surrounded by heat insulation walls other than the two heat transfer surfaces is formed against the external environment where the temperature fluctuates around the average temperature at each position in time. External environment where heat conduction between the external environment and the internal space through each heat transfer surface fluctuates around the average temperature of one heat transfer surface higher than the other heat transfer surface due to the effect of spatial temperature distribution In the case of touching, it is realized under the influence of the latent heat storage material (or chemical heat storage material) that is the phase transition temperature (or reaction temperature) around the average temperature of the external environment in contact with each other, or the spatial environment of the external environment If the heat transfer surface is exposed to an external environment where both heat transfer surfaces fluctuate around the same average temperature due to a small temperature distribution, the phase transition is higher than the average temperature of the temperature change on one heat transfer surface and lower than the maximum temperature. Temperature (or reaction temperature) Latent heat storage material (or reaction temperature) that is realized under the influence of latent heat storage material (or chemical heat storage material) and has a phase transition temperature (or reaction temperature) lower than the average temperature of temperature fluctuation and higher than the minimum temperature on the other heat transfer surface ( It is also characterized by the fact that it is realized while being influenced by chemical heat storage materials), and generates a spontaneous and steady temperature difference and a steady and unidirectional heat flow in the internal space from the external environment where the temperature fluctuates. Heat transfer mechanism.   The heat transfer mechanism according to claim 1, wherein the latent heat storage material (or chemical heat storage material) having a predetermined phase transition temperature (or reaction temperature) that affects heat conduction between the external environment and the internal space is heat conduction. Excellent thermal conductivity in a latent heat storage material (or chemical heat storage material) dispersed as a sub-system such as a microcapsule in a material with excellent properties, or conversely, having a predetermined phase transition temperature (or reaction temperature) A heat transfer mechanism characterized in that it is a composite material in which particles, fibers, and the like are dispersed, and a unidirectional heat flow is constantly generated in the internal space from an external environment in which the temperature fluctuates.   An energy conversion mechanism for propelling a power generation mechanism, a power source, a chemical reaction, and the like by utilizing a temperature difference generated in the internal space of the heat transfer mechanism according to claim 1.   4. The heat transfer mechanism and energy conversion mechanism according to claim 1, wherein an external asymmetry of heat flow from the external environment coincides with a direction of heat flow due to a temperature difference caused by an internal latent heat storage material (or chemical heat storage material). It is characterized by introducing a heat rectifying mechanism at the boundary between the environment and the latent heat storage material or chemical storage material), and generating a unidirectional heat flow in the internal space from a temperature-fluctuating external environment Heat transfer mechanism and energy conversion mechanism.