WO2017166102A1

WO2017166102A1 - Thermal energy utilization system

Info

Publication number: WO2017166102A1
Application number: PCT/CN2016/077819
Authority: WO
Inventors: 胡笑平
Original assignee: 博立多媒体控股有限公司; 胡笑平
Priority date: 2016-03-30
Filing date: 2016-03-30
Publication date: 2017-10-05

Abstract

Provided is a thermal energy utilization system, comprising at least two thermal energy storage units (S11, S12) and at least one thermoelectric conversion device (C21, C22). Each of the thermal energy storage units (S11, S12) comprises a thermal energy storage medium (M31, M32), at least one thermal energy inflow end, and at least one thermal energy outflow end, wherein one thermal energy outflow end of at least one thermal energy storage (S11, S12) is connected in series with one thermal energy inflow end of another thermal energy storage (S11, S12), and thermal storage media of the two thermal energy storage units (S11, S12) are different substances. The thermoelectric conversion device (C21, C22) is arranged on a thermal energy channel. The thermal energy utilization system has two cascade-connected thermal energy storage units (S11, S12) and thus has a multi-level temperature difference, such that the thermoelectric conversion device (C21, C22) can be arranged between a thermal source (T40) and the thermal energy storage units (S11, S12) or between the cascade-connected thermal energy storage units (S11, S12). In addition, the two cascade-connected thermal energy storage units (S11, S12) use different media, so that more thermal energy can be stored, and the thermal energy can be utilized in different manners.

Description

Title of Invention: Thermal Energy Utilization System

Technical field

[0001] The present invention relates to the field of energy storage and utilization technologies, and more particularly to a thermal energy utilization system capable of both storing energy and generating electricity.

BACKGROUND OF THE INVENTION

[0003] The storage of energy is an important issue that needs to be addressed in the development of new energy.

[0004] Existing energy storage technologies are mainly battery-based, especially rechargeable lithium ion batteries, lead-acid batteries, nickel-hydrogen batteries, fluid batteries, and the like. Since battery energy storage is primarily dependent on chemical reactions, there are potential chemical hazards and it is often desirable to use relatively rare chemical materials such as lithium. Therefore, there is still a need to develop safer and cheaper energy storage systems.

SUMMARY OF THE INVENTION

In accordance with the present invention, a thermal energy utilization system is provided that includes at least two thermal energy stores and at least one thermoelectric conversion device. Each thermal energy storage device includes a thermal storage medium and at least one thermal energy inflow end and at least one thermal energy outflow end, the thermal storage medium is configured to store thermal energy flowing in the thermal energy inflow end, and release thermal energy to the thermal energy outflow end; wherein, at least one One thermal energy outflow end of the thermal energy storage is in series with one thermal energy inflow end of the other thermal energy storage, and the thermal storage fluids of the two thermal energy storages are different substances. The thermoelectric conversion device is disposed on the thermal energy path between the heat source and the thermal energy storage device closest to the heat source, or is disposed on the thermal energy path between the two thermal energy storage devices connected in series, or is disposed at the thermal energy storage device and the external device farthest from the heat source. Thermal energy is utilized on the thermal energy path between the devices.

[0007] The use of thermal energy storage to store energy has the advantage of high energy density and low cost. The thermal energy utilization system according to the present invention has two cascaded thermal energy memories and thus has a multi-stage temperature difference, thereby facilitating the provision of a thermoelectric conversion device between the heat source and the thermal energy storage or between the cascaded thermal energy storage, utilizing the process of heat conduction. Power generation, achieving virtually lossless energy utilization. And the two cascaded memories use different working fluids, so they have different melting points or boiling points, wherein the working medium with higher phase transition temperature is favorable for safe and stable storage, and the working medium with lower phase transition temperature is more liable to liquefy or Vaporization absorbs a large amount of thermal energy. This configuration is beneficial for both storing more energy and for different ways of utilizing thermal energy. The specific examples according to the present invention will be described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic structural view of a thermal energy utilization system according to the present invention;

2 is a schematic structural view of a thermal energy utilization system of Embodiment 1;

3 is a schematic structural view of a thermal energy utilization system of Embodiment 2;

4 is a schematic structural view of a thermal energy utilization system of Embodiment 3.

DETAILED DESCRIPTION

[0015] A basic structure of the thermal energy utilization system according to the present invention can be referred to FIG. 1, including a first thermal energy storage S11, a second thermal energy storage S12, a first thermoelectric conversion device C21, and a second thermoelectric conversion device C22.

[0016] Each thermal energy storage device includes a thermal storage medium and at least one thermal energy inflow end and at least one thermal energy outflow end, wherein the thermal storage medium is used for storing thermal energy flowing in from the thermal energy inflow end, and releasing thermal energy to the thermal energy outflow end. . For example, the first thermal energy storage S11 includes a thermal storage medium M31, and the second thermal energy storage S12 includes a thermal storage medium M32. The lower portions of the two thermal energy storages are all thermal energy inflow ends and the upper portions are thermal energy outflows.

[0017] The thermal energy from the heat source T40 flows in from the lower portion of the first thermal energy storage device S11, and the thermal energy outflow end of the first thermal energy storage device S11 is connected in series with the thermal energy inflow end of the second thermal energy storage device S12, as indicated by the arrow in FIG. The direction in which heat flows. For simplicity, only two cascaded thermal energy stores are shown in Figure 1, and in various embodiments, more thermal energy storage may be configured. Each thermal energy store can also have more than two thermal energy inflows or outflows to facilitate the construction of the various thermal pathways required in the design.

[0018] According to the present invention, a plurality of thermal energy memories may be either sub-secondary or have a more complicated thermal energy path connection relationship as long as one thermal energy outflow end of at least one thermal energy storage device and another thermal energy storage device are A heat energy inflow end can be connected in series. For example, one thermal energy inflow of at least one thermal energy store may be in parallel with one thermal energy inflow of another thermal energy store, or one thermal energy outflow of at least one thermal energy store may be in parallel with a thermal energy outflow of another thermal energy store. As another example, a plurality of sequentially connected thermal energy stores can be coupled in parallel with another set or sets of thermal energy stores in series to facilitate rapid input or output of a large amount of thermal energy. For another example, a plurality of thermal energy memories connected in series on one thermal energy path may be parallel in another thermal energy path, and the operating mode of the thermal energy storage can be selected and controlled by turning on or off the corresponding thermal energy path. [0019] In terms of morphological structure, a plurality of thermal energy memories may be stacked in various different manners, for example, may be arranged in an inner and outer nesting manner, or may be arranged in a stacked manner, or arranged in a horizontal arrangement. .

[0020] The heat storage medium M31 of the first thermal energy storage S11 and the heat storage medium M32 of the second thermal energy storage S12 are different substances. The heat storage medium can be selected according to the working environment, the way of utilizing heat energy, and the like, for example, it can be selected from molten salt, paraffin, 7j, coolant, silica gel, low melting point or low boiling metal compound, air, etc.

[0021] As a preferred embodiment, for two thermal energy memories connected in series, the heat storage medium of the thermal energy storage device closer to the heat source on the thermal energy path has a smaller specific heat capacity, or the same phase change type. In this case, the phase transition temperature is higher. For example, the heat storage medium M31 of the first thermal energy storage may be selected from a molten salt (such as a mixture of potassium nitrate and sodium nitrate, or iron nitrate, etc.), a paraffin wax, and the like having a higher specific heat capacity and a higher melting point and a higher boiling point; The thermal storage medium M32 of the thermal energy storage device can select a working medium having a lower melting point and a lower boiling point such as water or a coolant; this makes the first thermal energy storage more convenient for large-scale and long-term storage of energy, and the second thermal energy storage can also be used on the one hand. A large amount of energy is stored by phase change, on the one hand, the operating temperature is lower and the use of heat energy is more convenient.

[0022] There are two ways to form a thermal energy path between the thermal energy storage device and the outside world. One is to flow through the working medium, that is, to connect the working medium in the thermal energy storage with other devices. The other is by means of heat conduction, in which case the thermal energy store is substantially equivalent to a closed container (which may have any desired shape), the wall of which may be divided into a heat conducting wall and a heat insulating wall, wherein The heat energy inflow end or the heat energy outflow end is formed as a heat conducting wall, and other positions are formed as heat insulating walls. In order to facilitate the long-term storage and controllable use of thermal energy, the heat-conducting wall can also be provided with a passageway (for example, a heat-insulating wall that can be twisted) to control the inflow or outflow of thermal energy through the passage. In both of the above thermal energy flow modes, the thermal energy storage can be considered to be relatively closed, and both the thermal energy and the working fluid flow in a closed or controllable manner.

[0023] The first thermoelectric conversion device C21 is disposed on the thermal energy path between the heat source T40 and the thermal energy storage device closest to the heat source (ie, the first thermal energy storage S11), and the second thermoelectric conversion device C22 is disposed in the two thermal energy storage devices S11 connected in series On the thermal energy path between S12 and S12. The thermoelectric conversion device is usually a device that uses thermoelectric power generation, such as a semiconductor thermoelectric power generation device, which includes two heat conduction ends and is connected in series to the thermal energy path. In the case where the temperature of one heat conduction end (heat energy inflow) is higher than the temperature of the other heat conduction end (thermal energy outflow), the thermoelectric conversion device outputs electric energy.

[0024] Temperature differences across the thermal energy path are ubiquitous. For example, if the thermal storage medium M32 of the second thermal energy storage has a lower melting point and boiling point, when the two temperatures are reached, the temperature of the second thermal energy storage is not easily changed, and if the thermal storage medium of the first thermal energy storage device M31 has a relatively high melting point and boiling point, and its temperature is relatively easy to rise under the action of an external heat source, which causes a large temperature difference, thereby facilitating temperature difference power generation. According to the present invention, a larger number of thermoelectric conversion devices can be disposed on all of the thermal energy paths having temperature differences at both ends, and of course, only one thermoelectric conversion device can be provided, which can be determined according to actual needs. The provision of the thermoelectric conversion device can improve the efficiency of thermal energy utilization, and in the present invention, the thermoelectric conversion process of the thermoelectric conversion device is almost non-destructive because the electric energy consumed by the internal resistance still becomes thermal energy and is thus stored or utilized.

[0025] As a preferred embodiment, the thermoelectric conversion device may be provided with a control switch capable of switching between the on and off states, performing temperature difference power generation in the on state, and acting as direct thermal energy in the off state. path.

As a preferred embodiment, the thermoelectric conversion device may employ a reversible thermoelectric conversion device such that the end for the inflow of thermal energy and the end for the outflow of thermal energy can be reversed. Therefore, the operating state of the thermoelectric conversion device can be switched according to the temperature change at both ends thereof. For example, when the temperature difference is reversed, the cooling end is switched to the heat source end, and the heat source end is switched to the cooling end.

[0027] The heat source referred to in the present invention may be various natural energy sources or artificial devices capable of generating thermal energy. For example, it may be solar energy, a photoelectric conversion device using solar energy, an electric heating device, a microwave heating device, a combustion heat generating device, or the like.

[0028] The system according to the invention is exemplified below.

Embodiment 1

[0030] An embodiment of a thermal energy utilization system according to the present invention may refer to FIG. 2, including a first thermal energy storage device 11 11 , a second thermal energy storage device 112 , a first thermoelectric conversion device 121 , a second thermoelectric conversion device 122 , and a cooling system 150.

[0031] In this embodiment, the heat source is the photovoltaic panel 140, and the sunlight (shown by the arrow in FIG. 2) is first irradiated on the reflective concentrating system 141, and is reflected and concentrated to be irradiated onto the photovoltaic panel 140. Reflective concentrating system It is used as a concentrated Fresnel lens with a reflective film on its bottom.

[0032] The thermal energy generated by the photovoltaic panel 140 flows into the first thermal energy storage device 111 via the first thermoelectric conversion device 121, and the first thermal energy storage device 111 and the second thermoelectric conversion device 122 and the second thermal energy storage device 112 are sequentially connected. The walls of the thermal energy storage for the inflow or outflow of thermal energy are formed as heat conducting walls, and the walls of other locations are formed as insulating walls. The first thermal energy storage 111 includes a thermal storage medium 131, and the second thermal energy storage 112 includes a thermal storage medium 132.

[0033] The cooling system 150 for utilizing thermal energy in this embodiment includes a cooling medium and a piping system 151 that controls the flow of the cooling medium. A piping system usually consists of several pipes and a number of valves that control the opening and closing of the pipes. Each valve can control a length of pipe. For the sake of simplicity, only two valves Va disposed on the pipe are schematically depicted in Figure 2. It is obvious that all or part of the pipe can be configured with valves as needed. The valve can be an automatic valve, such as a valve that is opened or closed by pressure control in the pipe, or a valve that is electrically controlled according to the instructions of the external control system. The valve can also be used to control the flow.

[0034] The cooling system in this embodiment realizes the utilization of thermal energy by liquid vaporization, and thus further includes a gas compressor (or pump) 152 and a gas-powered generator 153, which are all connected in the piping system by cooling. Working fluid drive. The form of the cooling medium may be in a gaseous state, or in a liquid state, or may vary between a gaseous state and a liquid state.

[0035] The piping system 151 is in communication with the second thermal energy storage 112, so that the thermal storage medium 132 of the second thermal energy storage is a cooling medium. Since the heat storage medium 132 as a cooling medium needs to be vaporized, it is possible to use a liquid which is easy to vaporize, such as water, a coolant, alcohol, or a compound having a relatively low melting point and a low boiling point (e.g., Boron Bromide). For the home system, the working fluid 132 can be water, then the gas compressor 152 can be replaced by a water heater (or an additional water storage water heater) by connecting the inlet (cold water) and the effluent (hot water) pipeline to the water heater. (not shown) to provide domestic water.

[0036] In this embodiment, the thermal energy storage device exchanges heat with a device (cooling system) that utilizes thermal energy in a working medium communication manner. In other embodiments, the second thermal energy storage device may also adopt a closed container through a heat conducting wall and cooling. The system is thermally connected. For example, the second thermal energy store can be arranged by means of a thermoelectric conversion device or directly via a heat-conducting wall and a water tank in the cooling system. As another example, the piping system can pass through at least one thermal energy storage, in which the cooling medium passes through the piping wall and the thermal energy The heat storage medium of the memory is heat exchanged.

[0037] The thermal energy utilization system of the embodiment has a simple structure, a large energy storage density and is easy to be miniaturized, can be operated with a safe working medium and operates at a safe (not too high) temperature, and is suitable for home-type energy storage, or Energy storage in the short term (for example, at night or within a few days).

Embodiment 2

[0039] Another embodiment of the thermal energy utilization system according to the present invention may refer to FIG. 3, including a first thermal energy storage 211, a second thermal energy storage 212, a third thermal energy storage 213, a first thermoelectric conversion device 221, and a second thermal power. The conversion device 222, the third thermoelectric conversion device 223, and the cooling system 250.

[0040] The heat source 240 in this embodiment may be selected from various types such as an electric heating device, a combustion heating device, a microwave heating device, and the like. An active heat shield (not shown) can be placed between the heat source and the heat utilization system. When the heat shield is inserted between the heat source and the heat utilization system, the heat energy path is broken, and when the heat shield moves, the heat energy The path is turned on.

[0041] The three thermal energy memories 211, 212, and 213 are sequentially connected in series to the thermal energy path behind the heat source 240 through the three thermoelectric conversion devices 221, 222, and 223. The first thermal energy storage device includes a thermal storage medium 231, the second thermal energy storage device includes a thermal storage medium 232, and the third thermal energy storage device includes a thermal storage medium 233.

[0042] The cooling system 250 includes a cooling medium (flowing as indicated by the arrows in FIG. 3) and a piping system 251 that controls the flow of the cooling medium. A compression pump 252 and a steam turbine 253 are connected in the piping system for achieving thermal energy utilization. In this embodiment, the thermal energy stores are all closed containers, and the cooling medium of the cooling system exchanges heat with the thermal energy storage through the pipes passing through the respective thermal energy stores. Specifically, the cooling system further includes a vaporization chamber 254 and a corresponding reservoir 255 through which three conduits in communication with the vaporization chamber pass through the three thermal energy stores, respectively. Therefore, the three thermal energy memories are in parallel relationship with each other with respect to the thermal energy path with the cooling system. The thermal energy path between the thermal energy storage and the cooling system can be turned on or off by controlling the valves Val and Va2 of the conduit through the thermal energy store.

[0043] As a preferred embodiment, the vaporization chamber 254 is also thermally coupled to the heat source 240. This allows the vaporization chamber to be used for both thermal energy storage and thermal energy output to the cooling system, as well as for the heat source to input thermal energy to the three thermal energy stores. When the thermal energy store outputs thermal energy, the valves Val and Va2 can be opened simultaneously, so that the cooling medium can be cycled and the energy is continuously output. When the thermal energy is input to the thermal energy storage, the valve Val can be closed and the valve Va2 can be closed, so that the cooling medium acts as a heat source. The heat transfer medium between the three thermal energy stores enables energy storage faster.

[0044] This parallel energy input or output mode greatly increases the efficiency of energy flow, and the speed of energy transfer can be controlled by valves, which can be used for energy storage of large power plants. And because the thermal energy storage uses a sealed structure, it is easier to achieve a safe, high-density, long-term energy storage system by controlling the energy output through the valve.

Embodiment 3

[0046] Another embodiment of the thermal energy utilization system according to the present invention may refer to FIG. 4, including a first thermal energy storage 311, a second thermal energy storage 312, a third thermal energy storage 313, and four thermoelectric conversion devices 321, 322, 323. And 324, and a compressed air tank 350 for use as a cooling system.

[0047] The heat source in this embodiment is a solar energy receiving container 340. After the sunlight is concentrated by the two-stage condenser lens 341, it is guided through the light guide 342 into the solar energy receiving container. At the position where the light guide enters the container 340, a beam splitter 343 is provided for changing the direction in which light enters the container , so that light is not easily reflected from the entrance. The container 340 can be used simply to collect the thermal energy of the sunlight, or to provide a photovoltaic panel therein, and to provide electrical energy to the same source as the heat source. The two-stage condenser lens 341 can be used as a concentrated Fresnel lens. The heat source and thermal energy utilization system may be disposed below the heat insulation layer 344, and the heat insulation layer may be a heat insulation layer on the top of the building (e.g., a building) or on the ground, or may be a tweezers made of heat insulating material floating on the sea surface.

[0048] The three thermal energy memories in this embodiment are cascaded and are structurally nested with each other, and the heat source 340 is disposed inside the thermal energy storage 311 closest to the heat source. The wall of the first thermal energy store that encloses the heat source acts as a thermal energy inflow end. The solar energy receiving container 340 and the outer wall of each thermal energy storage are provided with thermoelectric conversion means to make full use of the temperature difference of the various stages on the thermal energy path. This nested structure eliminates heat exchange between the thermal energy storage and the outside, in addition to the outermost compressed air canister, reducing energy losses. Especially when the inside of the compressed air tank is evacuated, the energy in the three thermal energy stores can be efficiently stored for a long period of time (e.g., half a year).

[0049] The heat storage granules 331, 332 and 333 of the three thermal energy memories are available in a variety of options. As a preferred embodiment, the first thermal energy storage device is a molten salt battery, the working medium 331 is a medium of a molten salt battery (for example, sodium sulfide), and the second thermal energy storage is a common molten salt thermal storage, and the working medium 332 is common. A molten salt (such as a mixture of potassium nitrate or sodium nitrate), the third thermal energy storage is a water tank, and the working medium 333 is fresh water or sea water.

[0050] The compressed air tank 350 may be connected to an external steam turbine or an air compressor or the like (not shown) to realize The use of heat energy will not be repeated here.

[0051] The system of the present embodiment can be used for heating and power supply of residential buildings, buildings, hotels, water surface facilities, and the like. In applications with high safety requirements, on the one hand, the safety of the system can be reduced by using safe thermal storage fluids; on the other hand, it can be set in various working areas of the system, especially in each thermal energy storage. Temperature/pressure measuring elements, automatic pressure relief ports, and equipped with appropriate alarm systems and automatic handling safety systems. These auxiliary devices and control systems are applicable to various embodiments in accordance with the present invention, and those skilled in the art can make selections and configurations as needed.

The above embodiments are intended to be illustrative of the principles and embodiments of the present invention. It is understood that the above embodiments are only intended to aid the understanding of the invention and are not to be construed as limiting. Variations to the above-described embodiments may be made by those skilled in the art in light of the teachings herein. technical problem

Problem solution

Advantageous effects of the invention

Claims

Claim

[Claim 1] A thermal energy utilization system, characterized in that

At least two thermal energy storage devices, each thermal energy storage comprising a thermal storage medium and at least one thermal energy inflow end and at least one thermal energy outflow end, wherein the thermal storage medium is used for storing thermal energy flowing in from the thermal energy inflow end, and flowing out to the thermal energy The end releases thermal energy; wherein, one thermal energy outflow end of the at least one thermal energy storage is in series with one thermal energy inflow end of the other thermal energy storage, and the thermal storage materials of the two thermal energy storages are different substances;

At least one thermoelectric conversion device disposed on a thermal energy path between the heat source and the thermal energy storage device closest to the heat source, or disposed on a thermal energy path between the two series of thermal energy storage devices, or disposed at a thermal energy farthest from the heat source The thermal energy path between the memory and the external thermal energy utilization device.

[Claim 2] The system of claim 1 wherein:

For two series-connected thermal energy stores, the heat storage medium of the thermal energy storage device closer to the heat source in the thermal energy path has a smaller specific heat capacity, or, in the case of the same phase change type, the phase transition temperature is higher.

[Claim 3] The system of claim 1 wherein:

A thermal energy inflow end of the at least one thermal energy store is coupled in parallel with a thermal energy inflow end of the other thermal energy store, or a thermal energy outflow end of the at least one thermal energy store is coupled in parallel with a thermal energy outflow end of the other thermal energy store.

[Claim 4] The system of claim 1 further comprising

a cooling system comprising a cooling medium and a piping system for controlling the flow of the cooling medium, the cooling medium being in a gaseous state, or a liquid state, or varying between a gaseous state and a liquid state, the piping system being in communication with the at least one thermal energy storage The heat storage medium of the connected thermal energy storage is the cooling medium; or the piping system passes through at least one thermal energy storage, and in the thermal energy storage that passes through, the cooling medium passes through the pipeline wall The heat storage medium of the thermal energy storage performs heat exchange.

[Clave 5] The system of claim 4, wherein the cooling system further comprises a gas compressor, or a gas-powered generator, coupled to the piping system.

[Clave 6] The system of claim 4, wherein

The piping system is in communication with a thermal energy storage that is furthest from the heat source; or

The cooling system also includes a vaporization chamber, wherein at least two conduits in the conduit system in communication with the vaporization chamber pass through at least two thermal energy stores in parallel, respectively.

[Claim 7] The system of claim 6, wherein the vaporization chamber is further thermally coupled to the heat source.

[Clave 8] The system of claim 1, wherein the heat source is disposed inside a thermal energy storage that is closest to the heat source.

[Claim 9] The system according to claim 1, wherein the thermal energy storage is arranged in a nested manner inside or outside, or arranged in a stacked manner above, or arranged in a horizontal arrangement

[Claim 10] The system of claim 1 further comprising one or more of the following features:

The heat source is selected from the group consisting of: a photoelectric conversion device using solar energy, an electric heating device, a microwave heating device, and a combustion heating device;

The heat storage working medium is selected from the group consisting of: molten salt, paraffin wax, 7j, coolant, silica gel, low melting point or low boiling point metal compound, air;

The thermal energy storage device is a relatively closed container, and the thermal energy inflow end or the thermal energy outflow end is formed as a heat conducting wall, and other positions are formed as heat insulating walls;

The thermoelectric conversion device is a semiconductor thermoelectric power generation device;

The thermoelectric conversion device is capable of switching between the on and off states, performing temperature difference power generation in the on state, and acting as a direct thermal energy path in the off state; the thermoelectric conversion device is a reversible thermoelectric conversion device, so that the thermoelectric conversion device is used The end where the thermal energy flows in and the end for the thermal energy can be reversed.