Heat-storage material and solar energy transformer based thereon
FIELD: heat-storage materials.
SUBSTANCE: invention relates to mixtures capable of accumulating heat energy and relevant solar energy transformers. Heat-storage material according to invention contains silicon dioxide, 3-5% of liquid soda glass, and 50-82% of VO2+x wherein x=0-0.5. Material is prepared by compacting mixture of vanadium dioxide VO2+x and silica in presence of liquid soda glass as binder followed by solidification at 150-200°C. Summary heat when using combined transformer including phase transformation heat (α-VO2 ↔ β-VO2) and oxygen adsorption-desorption heat of mechano-chemically treated VO2+x may reach 250 J/g.
EFFECT: increased heat-storage capacity.
8 cl, 1 tbl
The invention relates to mixtures for accumulation of thermal energy in the form of heat of phase transformation or heat generated by chemisorption of oxygen to the use of these mixtures as a means of accumulation of solar energy.
Increasing attention is paid to the use of renewable energy sources, particularly solar energy. In this regard, an important geographical latitude of the consumer and the number of Sunny days. A typical diagram of the solar power installation contains an element that absorbs solar radiation, the irradiated surface is protected by a translucent material, and the shadow side is covered by insulation. Inside the element is a circuit with a liquid coolant. Solar energy is absorbed by the surface element and the heat due to the mechanism of heat conduction in the summer, is transferred to the water coolant, and in the winter time is used for this purpose non-freezing fluid, such as antifreeze. To accumulate the necessary amount of heat in this installation uses water accumulator, which contains a large mass of water. From the energy point of view, the lack of such energy conversion is a slow mechanism of heat transfer by conduction from the element to the coolant. In addition, the level of temperature, get in the coolant due to solar energy is low, the density of the accumulated energy per unit mass of fluid is limited, and therefore the value of the stored thermal energy can be achieved by selecting the mass of the heat carrier.
To increase the efficiency of solar collectors offer different techniques. So, in the author's certificate of the USSR No. 868282, IPC3F 24 J 3/02, published 30.09.81, offers selective multilayer coating containing two layers, one of which is executed in the form of a film of aluminum oxide, the pores of which are filled with particles of metal type Nickel. The other layer is made in the form of a film of tin dioxide and is the first in the course of the sun's rays, and between the layers there is an additional bonding layer in the form of a film of hydrated aluminum oxide. Direct absorption of the rays and solar energy conversion into heat is transferred to the coolant (water).
The disadvantage of this solar collector is a low energy density per unit mass of fluid.
Known solar battery (USSR author's certificate No. 1537977, IPC5F 24 J 2/34, publ. 23.01.90 g)containing a thermally insulated housing with a translucent wall, located by the incident radiation, and thermal insulation article is ncoi, located on the opposite side, and the cavity of the housing is filled with the heat storage medium, undergoes a phase transformation. In the cavity of the housing parallel to the translucent wall mounted heat-conductive transparent partitions with the formation of several layers of thermal storage medium, and the temperature of the phase change thermal storage medium each subsequent layer in the direction from the translucent wall below the previous one, and the width of the layer in the same direction.
The disadvantage of this battery is the complexity of its use.
The closest technical solution to the claimed thermal storage is the mixture for accumulation and utilization of the heat of phase transformation (Patent RU №2104291, IPC 6 09 To 5/06, publ. 10.02.98 year), including magnesium nitrate, uranyl and lithium nitrate at a specific mass ratio.
The inventive heat-retaining mixture contains magnesium nitrate, and uranyl nitrate lithium mass ratio 86-81÷14-19 (preferably eutectic mixture mass ratio 83,7÷16,3).
The method of obtaining heat-retaining mixture comprises melting a mixture of magnesium nitrate uranyl (heat of fusion 100-135 j/g) and lithium nitrate in a weight ratio of 86-81÷14-19 in closed containers when the degree of filling is not bol is e 70% of its volume.
On GGS-diagram of this mixture of salts consisting of 83,7 parts by weight of Mg(NO3)2·6H2Oh and 16.3 parts by weight of LiNO3there is only accurate maximum value in the range from approximately 71 to 78°With the Central point of 75.6°C. the Heat of fusion calculated by summing the maximum values, which is 171,5 is j/g
The disadvantage of this mixture is that the mixture in the absorption of heat changes the state of aggregation and prolonged use changes are detected critical points of phase conversion and heat of phase transformation.
The problem solved by the invention is the creation of a heat-retaining mixture having stable properties without changing the aggregate state, and the development of an efficient Converter of solar energy with high energy density per unit mass heat storage composition.
The problem is solved due to the heat storage material comprising a compound of the metal and optionally silicon dioxide and sodium glass. As compounds of the metal it contains VO2+xwhere x=0-0,5, and a material obtained by extrusion of a mixture of vanadium oxide composition VO2+xwhere x=0-0,5, and silicon dioxide in the presence of liquid sodium glass as a binder in the following ratio com is onenow, wt.%:
|Vanadium oxide (VO2+xwhere x=0-0,5)||50-82|
|Liquid sodium glass|
followed by curing at a temperature of 150-200°C.
In thermal storage material preferably uses the heat of phase transformation α-VO2↔β-VO2.
The heat storage material as silicon dioxide contains natural or synthetic silica.
The heat storage material can be obtained by pressing a mixture of mechanochemical-treated vanadium oxide composition VO2+xwhere x=0÷0,5, when entered grinding bodies energy in the material 45-180 kJ/g) and silicon dioxide in the presence of liquid sodium glass as a binder.
In the heat storage material is used, the heat of adsorption (desorption) of oxygen mechanochemical-treated vanadium oxide composition VO2+xwhere x=0÷0.5, when entered grinding bodies energy in the material 45-180 kJ/year
In thermal storage material can be used in the heat of phase transformation α-VO2↔β-VO2and the heat of adsorption (desorption) of oxygen fur is ohimicheskie processed vanadium oxide.
The solar energy Converter comprises a solid heat accumulator, which is made of heat-retaining material composition corresponding to the above.
Liquid sodium glass is bonded with the molded plates of any given shape. The subsequent hardening of the mixture is carried out at a temperature of 150-200°s on the air. The finished plate have a compressive strength of 40 MPa. Plate in the Converter of solar energy collected, for example, packages etc.
For energy storage with high density is proposed to use a combined mechanism without changing the aggregate state, which involves the use of heat of phase transformation in the solid and / or heat generated by chemisorption of oxygen. To improve the efficiency of solar energy conversion and accelerate heat transfer is proposed to use the Converter in which the power transmission is performed through a combined mechanism of heat conduction and radiation. A combined mechanism of energy transfer can be obtained through use as a transformative element of a mixture of absorbing and scattering material.
The scattering substance in the present invention is silicon dioxide. The conversion of solar energy into heat in this case p is oshodi simultaneously throughout the volume element through the mechanisms of thermal conductivity and volumetric reemission, and increasing the density of the stored energy is achieved by transforming element contains the dispersed component (vanadium dioxide), a substance which has a phase transition of the 1st kind. In this case, the temperature of phase transformation should be, on the one hand, sufficient for use in space heating, and on the other hand, it is achievable in terms of solar radiation.
Solar energy Converter with solid-state accumulation of thermal energy has a number of advantages in comparison with any known solutions. The main advantage of the proposed Converter of solar energy is that its temperature remains unchanged during the entire selection process heat, and the heat is set by the duration of the phase transformation.
As the dispersed components that meet the above properties, it is proposed to use
1) vanadium dioxide VO2thermophysical characteristics of which are presented in [Krzyzanowski R.E., stern SU //Thermophysical properties of non-metallic materials, HP, Energy, 1973, 336 S.; Bugaev A.A., Zakharchenya BP, Chudnovsky FA // a Phase transition in metal - semiconductor and its application. Leningrad, Nauka, 1979, 183 S.]:
|Molecular weighttd align="right"> 165,880 g|
|Temperature conversion α-VO2-β-VO2||72°|
|Specific heat of transformation||1,02 (kcal/mol) (25,7 j/g)|
|Specific heat capacity at 300 K||27,96 (cal/mol·hail)|
|thermal conductivity||8 (W/m·hail)|
(table 1 - sample # 2);
2) mechanochemical treated vanadium oxide composition VO2+x(where x=0÷0,5) at the input of the grinding bodies energy in the material 45-180 kJ/g, which uses the heat of adsorption (desorption) of oxygen. Heat of adsorption (desorption) of oxygen in the temperature range from 50 to 180°presented in table 1, the number of samples 3 through 10);
3) or a mixture of vanadium dioxides 1) and 2).
A specific example of obtaining a heat-retaining material and the solar energy Converter based on it
To ensure volumetric absorption of incident solar energy and the maximum spatial uniformity of phase transformation in the proposed Converter vanadium dioxide (working substance) VO2mixed with filler particles of silicon dioxide, which can take a ground-up glass, then add liquid sodium glass as wag the future.
The vanadium oxide may be subjected to mechanochemical treatment.
The vanadium oxide composition VO2+x(where x=0÷0,5) is subjected to mechanochemical treatment in vysokoenergeticheskom the activator planetary centrifugal type with input grinding bodies energy in the material 45-180 kJ/g, mixed with ground glass and liquid sodium glass. The ratio of the components in both versions:
|liquid sodium glass|
|(in terms of dry residue)||5%,|
|ground-up glass with a particle size of 1-150 microns||rest|
The resulting mixture is molded at a pressure of 3-10 MPa (depending on the fractional composition and humidity of the mixture), dried in air, and then hardened by heating in air atmosphere up to 150-200°C. the resulting plates are going to work items of the solar energy Converter of a given size.
For convenience drafting table in the present method uses the term "introduced in the material energy" W. for them to understand the energy transmitted grinding bodies activator to one gram of the treated mixture. Calculation of W, j/g, was carried out according to the following formula:
W=To·(M balls/M mix)·the 3/2·t,
where a=n·g - acceleration (energonapryazhennosti activator),
n is a number equal to 20, 40, 60;
K - coefficient of proportionality between power and energonapryazhennosti mills; for this type of mill power, input balls when n=40, calculated by the formula N=K·(M balls/M mix)·and3/2equal to 50 W/g;
M balls is the mass of balls in the activator, g;
M mix - weight of the work in the activator mixture, g;
g - free fall acceleration;
t - time processing of the mixture in the activator, sec;
then W=N·t, j/,
|No.||Entered grinding bodies energy W, kJ/g||Q, j/g||Temperature conversion, °||The physical process of transformation heat|
|1 prototype||-||171.5||72,81||The heat of fusion|
|2||0||25,7||72||Heat of phase transformation|
|3||0||35.5||50-100||The heat of adsorption-desorption of oxygen|
|4||0||47.4||50-130||The heat of adsorption-desorption of oxygen|
|5||45||81.3||50-100||The heat of adsorption-desorption of oxygen|
|6||45||162.1||50-150||The heat of adsorption-desorption of oxygen|
|7||135||110.7||50-100||The heat of adsorption-desorption of oxygen|
|8||135||231.6||50-180||The heat of adsorption-desorption of oxygen|
|9||180||89.5||50-100||The heat of adsorption-desorption of oxygen|
|10||180||184.8||50-160||The heat of adsorption-desorption of oxygen|
The calculated total heat when using the combined Converter using the heat of phase transformation and heat of adsorption-desorption of oxygen can reach 250 j/g In table 1, this exemplary embodiment is not shown, although using transducers volume of their use will be significant.
When the number of VO2less than 50% efficiency of the solar energy Converter is reduced proportionally to the reduction of mass. The increase in the content of VO2more than 82% creates difficulties in forming plates.
The reduction in the content of liquid sodium glass below 3% (calculated on dry OST the current) leads to a decrease of the compressive strength of the finished plates up to 4 MPa, increasing the number of liquid sodium glass above 5% is impractical because of the increased humidity of the mixture, which also creates difficulties in forming plates.
Reducing the temperature of curing below 150°leads to insufficient strength and water resistance of the plates, the increase above 200°increases economic costs.
As an example, let us calculate the conversion of solar energy into thermal energy for latitude Novosibirsk work item size 1 m2thickness of 0.025 m, with the content of vanadium dioxide 80% (86,78 kg)glass 11 kg (weight 2200 kg/m3). The amount of solar energy for 1 month according to [the Handbook of the climate of the USSR, issue 20, part 1, HP, Hydrometeorological publishing house, 1966] on the selected work item of the transducer is Qthe u=10,7·104kcal/m2.
A work item of the Converter under the action of solar radiation heats up to the temperature of phase transformation (72°C), then for some time without changing temperature phase transition occurs (α→β).
The amount of heat required for carrying out this process will
where m is the mass, C is the heat capacity, Δt is the temperature difference from the start of heating until the temperature of the phase is the first transformation, Qphasesthe heat of transformation of vanadium dioxide, the indices 1, 2 - vanadium dioxide, glass, respectively.
The calculated heat of transformation of vanadium dioxide in a work item is
The amount of heat consumed for heating of vanadium dioxide and glass temperatures of phase transformations, is
QGeneral=1026,6+a 126.7+533,6=1686, kcal.
The average solar energy incident on the work item within one hour in the daytime , is
Since the proposed Converter of solar energy economically advantageous to operate in the regime of phase transformations, the time for performing phase transformations α→β this Converter (charge time) will be
Removing heat from the Converter of this type are most effectively implemented using convection cooling the working surfaces of the element air. The time spent on the removal of heat during the phase transformation β↔αis the ratio
where α is the coefficient of convective heat transfer (W/m2·hail), ΔT=50 - difference between the temperatures of the working element and obogrevateli the premises.
In this case, α≅10 W/m2·hail, then
Estimate the required number of converters of solar energy for space heating, based on existing standards.
According to the accepted norms in the month of April for heating at the latitude of the city of Novosibirsk (area of 260 m2height 3 m) is consumed within 1 hour at 1 m2
Since the discharge time of the solar inverter is ˜1 hour, the amount of energy stored by the Converter during charging, can provide a warm area
Thus, to ensure the warmth of the premises around the clock area of 100 m2in the month of April at the latitude of Novosibirsk will need a Converter of solar energy with a total area of 70 m2.
1. The heat storage material comprising a compound of the metal, characterized in that it further contains silicon dioxide and sodium glass, as the connection of the metal it contains VO2+xwhere x=0÷0.5 and material obtained by extrusion of a mixture of vanadium oxide composition VO2+xwhere x=0÷0.5 and silicon dioxide in the presence of liquid sodium glass as a binder in the following ratio, wt.%:
|Vanadium oxide (VO2+xwhere x=0÷0,5)||50-82|
|Liquid sodium glass|
followed by curing at a temperature of 150-200°C.
2. The heat storage material according to claim 1, characterized in that it uses the heat of phase transformation α-VO2↔β-VO2.
3. The heat storage material according to claim 1, characterized in that silicon dioxide it contains natural or synthetic silica.
4. The heat storage material according to claim 1, characterized in that it is obtained by pressing a mixture of mechanochemical-treated vanadium oxide composition VO2+xwhere x=0÷0,5, when entered grinding bodies energy in the material 45-180 kJ/g) and silicon dioxide in the presence of liquid sodium glass as a binder.
5. The heat storage material according to claim 4, characterized in that it uses the heat of adsorption (desorption) of oxygen mechanochemical-treated vanadium oxide composition VO2+xwhere x=0÷0,5, when entered grinding bodies energy in the material 45-180 kJ/year
6. The heat storage material according to claim 1, characterized in that it uses heat phase prevremeni the α -VO2↔β-VO2and the heat of adsorption (desorption) of oxygen mechanochemical-treated vanadium oxide.
7. Solar energy Converter, including solid-state heat accumulator, characterized in that the solid heat accumulator made of heat-retaining material composition corresponding to any one of claims 1-7.
8. The Converter according to claim 7, characterized in that it is made in the form of plates of predetermined shape and assembled in the package.
FIELD: power engineering and agriculture, applicable in production of a universal power carrier-hydrogen.
SUBSTANCE: the solar energy concentrator in the sea-based bioenergetic complex is made in the form of a pontoon frame with a heat-insulating membrane located inside it and supported by flexible pontoons, a lengthened reactor with biomass spores is installed on the membrane and heat-exchange pipes of thermocompressors positioned on the pontoons of the pontoon frame, also installed in which are saturators, biomass and water separators, methane-producing generators, nuclear reactors for heating of steam delivered to the converters from the thermocompressors to high temperatures, and a tank for storage of gases and water, and the outer side of the pontoon frame is additionally provided with coiled reactors with biomass spores supported by the flexible pontoons.
EFFECT: provided salvaging of carbon dioxide and production of hydrogen.
FIELD: solar power engineering.
SUBSTANCE: method is used for transforming sunbeam energy to thermal energy. Method is performed by means of sequent connection of solar beam concentrators. One of concentrators is composed of a field of local concentrators, which are built in heat-insulating lightproof material. The material embraces internal room of sunbeam-absorbing chamber. Built-in concentrators and sunbeam conductors have to be basically hollow truncated pyramids which have faces covered with beam-reflecting material. Bases of pyramids are closed by transparent heat-insulating material The second sunbeam concentrator has to be external one. Those concentrators preliminary have shape of truncated pyramid with faces covered with light-reflecting material. The third level of solar-beam pumping of sunbeam-absorbing chamber is created additionally due to creation of total filed of external sunbeam-reflecting surfaces in environment at different distances from sunbeam-absorbing chamber.
EFFECT: reduced cost of multistep pumping of solar power to sunbeam-absorbing chamber.
26 cl, 6 dwg
FIELD: the invention refers to small power engineering using renewable energy sources- Sun, wind, lifting of warm air upwards, difference of atmospheric pressure throughout the height.
SUBSTANCE: The electric power station has an accumulator of solar power and a tower which is equipped with aerodynamic facilities for transformation of solar and wind energy in electric power.
EFFECT: creation, building and exploitation of solar-vacuum electric power station in small towns and inhabited localities instead of diesel power stations and boiler rooms on solid fuel, transfer from hot-water heating to electric heating on a moderate price for inhabitants and local production allows to brighten economy of these settlements.
FIELD: development of power plants using solar energy.
SUBSTANCE: proposed method depends on conversion and storage of solar energy including generation of heat energy used to set air in rotary motion within solar collector wherein air ducts are organized, disposed in parallel, and connected in series with motion of energy-saturated air flow. Each of such ducts accommodates group of local tilted surfaces whereon sun rays are incident through light-translucent heat-insulating material, and controlled heat fluxes of process working medium conveyed from solar energy converters and accumulators of various types and potential levels are at the same time supplied to these ducts. In the process temperature irregularities occur within solar collector and its air ducts with the result that steady revolving air flows are set up both along air ducts and in their sectional areas, as well as in surface areas encouraging turbulent vortex motions.
EFFECT: enhanced power generation ensured by proposed method.
3 cl, 4 dwg
FIELD: solar wind power engineering.
SUBSTANCE: heater comprises electric generator with wind wheel, tail beam of rectangular cross-section, shaft, and tail assembly which is composed of two or more rhomboid panels provided with photoelectrical transducers from their sides. The ring water accumulator is mounted in the bottom section of the shaft and connected with the photoelectrical transducers. The rectangular water accumulator is connected with the electric generator. The cells filled with a heat accumulating agent are connected with the electric heaters mounted inside the accumulators. The temperature of phase transition of the agent should be within the range of operation temperatures of the accumulators.
EFFECT: enhanced efficiency.
1 cl, 1 dwg
FIELD: power engineering.
SUBSTANCE: solar power plant comprises concentrator, receiver of solar radiation, and accumulator. The concentrator is made of a transparent sphere filled with a transparent liquid for concentrating the light beam at the receiver of solar beams. The heat accumulator is provided with a coil.
EFFECT: enhanced reliability, simplified structure, and reduced cost.
FIELD: solar power engineering.
SUBSTANCE: solar power plant includes solar battery having at least two solar heat collector mutually joined through branch pipe. Said collectors are provided with individual heat pickups and individual pipelines for discharging hot water out of them through connection branch pipes. Shut-off devices are mounted in zones of crossing of branch pipes and pipelines. Pipeline for supplying water from accumulating tank to solar battery includes water pump; accumulating tank includes two heat exchangers of different volumes. Heat exchanger of large volume is designed for water used for heating; heat exchanger of small volume is designed for water used for domestic purposes. Solar heat collector includes transparent panel; heat absorbing panel in the form of set of parallel metallic tubes for liquid heat transfer agent connected with lower surface of metallic radiant-energy absorbing sheet; heat insulation layer and supporting heat insulation panel. Parallel metallic tubes of heat absorbing panel are pressed-in to metallic radiant energy absorbing sheet, they are arranged along short sides of said sheet and mutually connected by means of tubes arranged along long sides of sheet. Supporting heat insulation panel, heat insulation layer, heat absorbing and transparent panels are fluid-tightly connected one to other for forming rigid structure construction, for example with use of bolts. On upper and lower surface of said construction along its perimeter metallic or polymeric shapes are mounted.
EFFECT: enhanced efficiency of using solar energy.
17 cl, 3 dwg
FIELD: power engineering.
SUBSTANCE: plant has a circuit for circulation of working fluid. The circuit comprises steam generator provided with branch pipes for supplying fluid and discharging steam, steam turbine combined with the electric generator, regenerative heater with branch pipes for supply and discharge of heating and heated fluids, circulation pump for pumping fluid, circuit for circulation of heat carrier tank for exhaust heat carrier, and circulation pump for heat-transfer agent. The solar receiver is made of independent sections interconnected in parallel. The heat carrier circulation circuit is provided with pressure vessel.
EFFECT: enhanced serviceability and simplified design.
5 cl, 1 dwg
FIELD: solar power engineering.
SUBSTANCE: method comprises choosing region where underground water are very close to the surface and setting the vertical wells with face H = 25-30 m for lowering the level of soil water. The thickness of the ground layer is 10-20 m. The radius of the zone of the action of the vertical well is equal, e.g., 100 m. The device comprises solar-energy greenhouses with underground water carrying accumulator. Before the construction of the greenhouse, the level of the underground water should be lowered down to 2 m from the surface. The zone of action of the well is an overturned cone whose base radius is 100 m and top is in coincidence with the face of the well. The heating or cooling the heat carrying agent of the system for the air temperature control of the greenhouse is performed by means of solar power and/or the heat produced by the water carrying accumulator. The pipes of the temperature control system are also the members of the structure of the solar-energy greenhouse.
EFFECT: enhanced efficiency.
2 cl, 2 dwg