Concrete wall body temperature difference power generation device and graphene-concrete wall body manufacturing method thereof
Technical Field
The invention relates to a temperature difference power generation device and a preparation method of a concrete wall, in particular to a temperature difference power generation device of a concrete wall and a preparation method of a graphene-concrete wall of the temperature difference power generation device.
Background
The rapid development of the urbanization process has a serious influence on urban temperature, the urban heat island effect is increasingly obvious day by day, the rise of the temperature can bring more energy consumption, and researches show that the average temperature of the Nanjing city in August per day rises by 0.1 ℃ every time, and the maximum power load of the average day per month can increase by 4.1 ten thousand kW.
Under the direct sunlight condition in summer, the temperature of urban pavements and roofs can reach more than 65 ℃, and the indoor and outdoor temperature difference can reach more than 40 ℃. According to the invention, a heat collection system is used for collecting heat energy and solar energy in cities on the wall and the roof of a building, thermoelectric power generation is carried out by thermoelectric property of a concrete composite material prepared by adding a graphene-based cement base, and generated current is converted into direct current by a full-bridge circuit and is stored in a capacitor for use at any time.
Patent CN 201310330213.6 discloses a sandwich type cement-based thermoelectric material: two carbon fiber cement boards and a base thermoelectric material layer as a middle interlayer are tightly attached together for forming, and the interlayer type cement-based thermoelectric material is obtained by demolding and maintaining. The material is formed by splicing concrete and thermoelectric materials, the hot end of the thermoelectric materials is not heated sufficiently, the temperature difference is small, the energy conversion efficiency is reduced, the cohesiveness of the sandwich type splicing materials is reduced along with the influence of environment and time, and the later maintenance cost is high.
Patent CN 202010021335.7) discloses a building wall body temperature difference power generation system: arrange the thermoelectric material in building wall, wall both sides embedding conductor, when there is the difference in temperature inside and outside the wall, the heat passes through the thermoelectric material layer, and partial heat can be collected and convert usable electric energy into. Although the system utilizes thermoelectric material temperature difference to generate electricity, the following problems mainly exist: (1) the thermoelectric material is arranged in the wall body, so that the integrity of concrete in the wall body is damaged, the bearing capacity of the structure is reduced, and potential safety hazards exist; (2) a space is required to be reserved in the wall body for storing thermoelectric materials, and the thermoelectric material cannot be applied to high-rise buildings, bridges, pavements and other occasions; (3) the construction process is complex, the cost of thermoelectric materials is high, the energy conversion efficiency is low, and the large-scale application prospect is poor.
In conclusion, the prior art still has the problems that the temperature difference of the cold end and the hot end is not obvious, the bearing capacity of concrete cannot be fully utilized, and the construction and later maintenance costs are too high.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a concrete wall body temperature difference power generation device which has obvious temperature difference of a cold end and a hot end, strong bearing capacity and low cost; the invention also aims to provide a preparation method of the graphene-concrete wall.
The technical scheme is as follows: the concrete wall body temperature difference power generation device comprises a graphene-concrete wall body, a heat collection system arranged above the graphene-concrete wall body, and a rectifier, a controller and a capacitor which are sequentially connected with one side of the graphene-concrete wall body; the heat collection system comprises a blue film plating plate and a red copper runner arranged between the blue film plating plate and the graphene-concrete wall.
Furthermore, the red copper flow channel is filled with heat preservation liquid and a heat insulation layer wrapped around the heat collection system.
The solar heat collecting system further comprises an outer frame, wherein the outer frame comprises aluminum alloy frames arranged on the periphery of the heat collecting system and cover plate glass arranged in the aluminum alloy frames, and the cover plate glass covers the upper surface of the heat collecting system.
Further, the graphene-concrete wall is connected with the rectifier through a connector lug which is partially embedded in the graphene-concrete wall, and the connector lug comprises a first copper mesh electrode and a second copper mesh electrode.
Further, the blue membrane plated plate comprises a heat collecting plate core and a blue membrane coating plated on the outer layer of the heat collecting plate core, wherein the heat collecting plate core is a black chromium whole plate, and the blue membrane coating is a blue titanium coating; the heat insulation layer is 32K glass wool; the rectifier is formed by integrating four diodes according to certain arrangement; the capacitor is a self-healing low-voltage parallel capacitor.
Further, the graphene-concrete wall body comprises the following raw materials in parts by weight: 55-75 parts of cement, 10-20 parts of fly ash, 40-65 parts of aggregate, 5-10 parts of graphene nanosheet, 1-2 parts of water reducing agent, 5-10 parts of graphene oxide and 75-90 parts of water.
Further, the water reducing agent is a polycarboxylic acid water reducing agent; the cement is ordinary portland cement, the 28-day compressive strength of the cement is more than or equal to 42.5, the 28-day flexural strength of the cement is more than or equal to 6.5, and the specific surface area of the cement is more than or equal to 300.
Further, the thickness of the graphene nano-sheet is 10-20nm, and the surface area is 50-80m2g-1。
On the other hand, the preparation method of the graphene-concrete wall comprises the following steps:
(1) and grinding by a ball milling method to uniformly distribute the graphene nanosheets in the cement to obtain the graphene cement.
(2) And mixing the graphene oxide with a dispersing agent and an auxiliary dispersing agent, adding water, stirring, and performing ultrasonic dispersion to obtain a graphene dispersion liquid.
(3) Sequentially adding the graphene cement, the fly ash, the aggregate and the water reducing agent into the graphene dispersion liquid, adding water for mixing, and then carrying out mechanical gradient stirring to obtain a mixed material.
(4) The mixed materials are put into a prefabricated mould, and a copper mesh used as an electrode is embedded into the concrete wall.
(5) And (5) curing and drying the module after molding to obtain the product.
Further, the mass ratio of the used amount of each component in the graphene dispersion liquid in the step (2) to water is as follows: 3.0-5.0 wt% of graphene oxide, 0.1-1.0 wt% of dispersant and 0.05-0.5 wt% of auxiliary dispersant.
Further, in the step (3), the mechanical gradient stirring is performed by using a planetary stirrer to slowly stir at a speed of 50-60r/min for 5-10min, and then rapidly stir at a speed of 120-140r/min for 8-10 min.
Further, in the step (3), the ultrasonic dispersion power is 3000-.
Further, in the step (4), the mesh size of the copper mesh is 2.0 × 2.0mm2After being polished, the two copper nets are symmetrically embedded into the position 20mm away from the boundary of the concrete unit along the height of the sample, and the copper nets extend out of the boundary of the side face of the concrete unit by 10mm-20mm to be used as connector lugs of the energy collecting circuit.
Further, in the step (5), standing for 1-2 days at the room temperature of 20 ℃ +/-5 ℃ and under the environment that the relative humidity is more than 50%, removing the mold, putting the mold into a standard curing box, curing for 28 days, taking out the mold, putting the mold into an oven, and drying for 1-2 days at the temperature of 80 ℃, wherein the temperature of the standard curing box is 20 ℃ +/-2 ℃ and the relative humidity is more than 95%.
The working principle of the invention is as follows: the seebeck effect is derived from the distribution and movement characteristics of carriers inside the material, wherein the internal carriers are electrons carrying negative charges and holes carrying positive charges, and when a temperature difference exists between two ends of the thermoelectric material, the carriers near the hot end have higher kinetic energy than the carriers near the cold end. For a semiconductor material, the quantity of current carriers which are heated and excited near the hot end and enter a conduction band or a valence band is higher than that near the cold end, so that the diffusion of the current carriers from the hot end to the cold end is formed in the material;
the concrete disclosed by the invention has n-type conductivity and shows slight electron movement, and with the addition of the graphene p-type conductive material, hole movement exists in the graphene-concrete, so that electron hole distribution is formed in the composite material, the mechanical property of the concrete is kept, and the thermoelectric property of the concrete is enhanced. The indoor and outdoor temperature difference of the wall body built by the graphene-concrete material can reach more than 40 ℃ under the condition of direct sunlight blue film heat collection in summer. The temperature gradient causes the current carrier at the hot end to diffuse towards the cold end to form a temperature difference electromotive force, and then the current is unidirectionally moved through a full-bridge circuit formed by four diodes and stored in a capacitor to be used at any time.
Has the advantages that: compared with the prior art, the invention has the following remarkable advantages: (1) the thermoelectric generator made of thermoelectric material has the outstanding advantages of no mechanical movement, no noise, no abrasion, high reliability, no maintenance, no pollution, capability of designing the size and shape according to the requirement and the like;
(2) the efficient thick black chromium whole plate heat absorption blue film is used, nickel ion precipitation is increased, sunlight absorption efficiency is improved rapidly, high absorption, low emission and temperature rise are rapid, a large temperature difference can be generated, and power generation efficiency is improved;
(3) the graphene-concrete composite material has certain mechanical properties, good building structure integrity, excellent compression resistance, bending resistance and wide application range;
(4) the temperature difference of the cold end and the hot end is obvious, under the condition of sufficient solar energy, the heated fluid absorbs heat in the branch pipeline, the epoxy resin keeps the temperature, and a heat collection system can provide larger temperature difference to maintain power generation even at night and in rainy days;
(5) the full-bridge circuit built by four diodes can enable current to flow in a single direction, and the current generated by temperature difference power generation is stored in the capacitor in the same direction no matter the current is externally heated and internally cooled in summer or internally heated and externally cooled in winter.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of the summer operation of the present invention;
FIG. 3 is a diagram illustrating the working principle of the present invention in winter;
fig. 4 is a circuit diagram of the present invention.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings.
In the figure, 1, a red copper flow channel; 2. plating a blue film; 3. a thermal insulation layer; 4. an aluminum alloy frame; 5. a first copper mesh electrode; 6. a graphene-concrete wall; 7. a second copper mesh electrode; 8. a rectifier; 81. a first diode; 82. a second diode; 83. a third diode; 84. a fourth diode; 9. a controller; 10. a cathode terminal; 11. a capacitor; 12. an anode terminal; 13. a cement nail; 14. a cover glass.
Example 1
As shown in fig. 1, the concrete wall body temperature difference power generation device of the present invention includes a graphene-concrete wall body 6, a heat collection system, a control system and a power storage system, wherein the heat collection system is fixed on the graphene-concrete wall body 6, and the graphene-concrete wall body 6 is sequentially connected with the control system and the power storage system. The heat collection system comprises a red copper runner 1 and a blue film plating plate 2, wherein the red copper runner 1 is positioned between the blue film plating plate 2 and the graphene-concrete wall 6.
Specifically, the red copper runner 1 integrating the two main runners and the eight branch runners is tightly attached to the graphene-concrete wall 6 for direct heat transfer, and the blue film plating plate 2 covers the red copper runner 1 to realize efficient heat collection. Optionally, the diameter of the main pipe of the copper pipe in the red copper runner is 22mm, the diameter of the branch pipe is 10mm, and larger heat-insulating liquid is contained for lasting heat insulation; the blue film plating plate 2 is a high-efficiency thick black chromium whole plate coated with a blue titanium coating.
The concrete wall temperature difference power generation device further comprises an outer frame and a heat insulation system, wherein the outer frame comprises cover plate glass 14 and an aluminum alloy frame 4, the aluminum alloy frame 4 is used as a framework of the heat collection system and used for supporting the heat collection cavity, and the cover plate glass 14 is used for bearing pressure and protecting the internal structure;
specifically, in the outer frame, the aluminum alloy frame 4 is matched and erected on the graphene-concrete wall 6, holes with the diameter of 3mm are reserved on the four sides of the aluminum alloy frame, cement nails 13 are nailed into the graphene-concrete wall 6 along the holes by using a nail gun to fix the aluminum alloy frame 4, a framework forming a heat collection system is used for supporting a heat collection cavity, the size of the cement nails 13 is 1.5 inches, and the diameter of a nail cap is 5.9 mm. The cover plate glass 14 covers the blue film plating plate 2, and the cover plate glass 14 is fixed on the top plate of the aluminum alloy frame 4 by using an aluminum alloy pressing strip. The cover plate glass 14 is 3.2mm low-iron ultra-white cloth-grain high-transmittance toughened glass.
The heat insulation system comprises heat insulation liquid and a heat insulation layer 3, wherein the heat insulation liquid is injected into the red copper runner 1 and is used for absorbing heat and insulating heat; the periphery of the heat insulation layer 3 is wrapped by a central heat collection area, the heat insulation layer is embedded in a groove of the aluminum alloy frame 4, and the optional heat insulation layer is 32K glass wool.
The control system comprises a reactive power automatic compensation itemized controller and a rectifier, and the rectifier is connected with the controller through a lead; the electricity storage system comprises a capacitor, and the capacitor is connected with the control system through a lead.
The graphene-concrete wall 6 is connected with the control system through the connector lug, the connector lug comprises a first copper mesh electrode 5 and a second copper mesh electrode 7 which are symmetrically arranged, the first copper mesh electrode 5 and the second copper mesh electrode 7 are embedded into the graphene-concrete wall 6 along the height distribution, extend out of the side boundary of the concrete unit by 10mm-20mm and are used as the connector lug of the energy collecting circuit. Specifically, the first copper mesh electrode 5 and the second copper mesh electrode 7 are respectively connected with two alternating current ends of a rectifier 8 by leads, the positive end and the negative end of the rectifier 8 are connected with an electrode at one end of a controller 9, the positive electrode at the other end of the controller 9 is connected with an anode binding post 12 of a capacitor 11, and the negative electrode is connected with any one of cathode binding posts 10 of the capacitor 11. The rectifier 8 is formed by integrating four diodes according to certain arrangement, the controller 9 is a reactive power automatic compensation itemizing controller, and the capacitor 11 is a self-healing low-voltage parallel capacitor.
In addition, the concrete wall temperature difference power generation device also comprises a sensor, which is used for intelligently monitoring the running process of the device and realizing automatic management: the sensors are embedded in two sides of the graphene-concrete wall 6: specifically, the sensor includes a temperature sensor and a thermoelectromotive force sensor. Wherein, temperature sensor is used for taking notes 6 both sides difference in temperature of graphite alkene-concrete wall body, has embedded temperature sensor at the wall body both sides, records both sides temperature value in step, can obtain both sides wall body temperature difference like this, and the thermoelectromotive force sensor can adopt the voltmeter, and the copper mesh is embedded at the wall body both ends, because the difference in temperature at both ends is different, has the electric current to produce after first copper mesh electrode 5 in wall body both ends and second copper mesh electrode 7 intercommunication, inserts the voltmeter and can obtain thermoelectromotive force in the circuit.
As shown in fig. 2-3, the specific connection method and power generation principle of the lead are as follows: the first copper mesh electrode 5 is connected with the joint of the first diode 81 and the second diode 82 in the rectifier 8 by a lead A, and the second copper mesh electrode 7 is connected with the joint of the third diode 83 and the fourth diode 84 in the rectifier 8 by a lead B; the junction of the first diode 81 and the fourth diode 84 in the rectifier 8 is connected to the anode terminal 12 of the capacitor 11 through the controller 9 by a lead D, and the junction of the second diode 82 and the third diode 83 in the rectifier 8 is connected to any one of the cathode terminals 10 of the capacitor 11 through the controller 9 by a lead C. The full-bridge circuit built by four diodes can enable current to flow in a single direction, the current generated by thermoelectric power generation is stored into the capacitor in the same direction no matter the current is heated and cooled externally in summer or heated and cooled externally in winter, the positive and negative electrodes do not need to be adjusted manually, and the full-bridge circuit is free of maintenance and adjustment for power generation all the year round.
Example 2
The graphene-concrete wall comprises the following raw materials in parts by weight: 55 parts of cement, 10 parts of fly ash, 40 parts of aggregate, 5 parts of graphene nanosheets, 1 part of polycarboxylic acid water reducing agent, 5 parts of graphene oxide and 75 parts of water. Wherein the cement is ordinary portland cement, the 28-day compressive strength of the cement is more than or equal to 42.5, the 28-day flexural strength of the cement is more than or equal to 6.5, and the specific surface area of the cement is more than or equal to 300. The thickness of the graphene nano-sheet is 10-20nm, and the surface area is 50-80m2g-1. Graphene oxide can be prepared according to patent CN 202110124791.9.
The graphene-concrete wall is prepared in the following way:
1) putting the graphene nanosheets and cement into a zirconia ball planetary ball mill, and grinding by using a ball milling method to uniformly distribute the graphene nanosheets in the cement to obtain the graphene cement, wherein the rotating speed of the ball mill is 600r/min, and the preset ball milling time is 12 h.
2) Mixing graphene oxide with a dispersing agent and an auxiliary dispersing agent, adding water, stirring, and performing pre-dispersion to obtain a pre-dispersion liquid, and performing ultrasonic dispersion on the pre-dispersion liquid by using an ultrasonic dispersion instrument to obtain a graphene dispersion liquid, wherein the mass ratio of the using amount of each component in the graphene dispersion liquid to water is as follows: 3.0 wt% of graphene oxide, 0.1 wt% of dispersant and 0.05 wt% of auxiliary dispersant; the pre-dispersion stirring speed is 130r/min, the temperature is 15 ℃, and the stirring time is 20 min; the ultrasonic dispersion power is 3000W, the ultrasonic stirring speed is 50r/min, the ultrasonic temperature is 30 ℃, and the ultrasonic stirring time is 25 min.
3) Sequentially adding the graphene cement, the fly ash, the aggregate and the water reducing agent into the graphene dispersion liquid, adding water for mixing, and performing mechanical gradient stirring; the mechanical gradient stirring is that a planetary stirrer is adopted to stir for 5min at a low speed of 50r/min and then stir for 8min at a high speed of 120 r/min.
4) Placing the stirred mixture into a prefabricated mould, and embedding a copper mesh serving as an electrode into a concrete wall; the mesh size of the copper mesh is 2.0 multiplied by 2.0mm2After being polished, the two copper nets are symmetrically embedded into the position 20mm away from the boundary of the concrete unit along the height of the sample, and the copper nets extend out of the boundary of the side face of the concrete unit by 10mm-20mm to be used as connector lugs of the energy collecting circuit.
5) And (3) after the module is formed, standing for 1 day in an environment with the room temperature of 20 +/-5 ℃ and the relative humidity of more than 50%, removing the module, putting the module into a standard curing box for curing for 28 days, taking out the module, putting the module into an oven, and drying for 1 day at the temperature of 80 ℃ to dry the residual water in the graphene-concrete composite material module.
Example 3
The graphene-concrete wall comprises the following raw materials in parts by weight: 75 parts of cement, 20 parts of fly ash, 65 parts of aggregate, 10 parts of graphene nanosheets, 2 parts of polycarboxylic acid water reducing agent, 10 parts of graphene oxide and 90 parts of water.
The graphene-concrete wall is prepared in the following way:
1) putting the graphene nanosheets and cement into a zirconia ball planetary ball mill, and grinding by using a ball milling method to uniformly distribute the graphene nanosheets in the cement to obtain the graphene cement, wherein the rotating speed of the ball mill is 600r/min, and the preset ball milling time is 12 h.
2) Mixing graphene oxide with a dispersing agent and an auxiliary dispersing agent, adding water, stirring, and performing pre-dispersion to obtain a pre-dispersion liquid, and performing ultrasonic dispersion on the pre-dispersion liquid by using an ultrasonic dispersion instrument to obtain a graphene dispersion liquid, wherein the mass ratio of the using amount of each component in the graphene dispersion liquid to water is as follows: 5.0 wt% of graphene oxide, 1.0 wt% of dispersant and 0.5 wt% of auxiliary dispersant; the pre-dispersion stirring speed is 150r/min, the temperature is 15 ℃, and the stirring time is 20 min; the ultrasonic dispersion power is 6000W, the ultrasonic stirring speed is 100r/min, the ultrasonic temperature is 50 ℃, and the ultrasonic stirring time is 30 min.
3) Sequentially adding the graphene cement, the fly ash, the aggregate and the water reducing agent into the graphene dispersion liquid, adding water for mixing, and performing mechanical gradient stirring; the mechanical gradient stirring is that a planetary stirrer is adopted to stir at a low speed of 60r/min for 10min and then at a high speed of 140r/min for 10 min.
4) Placing the stirred mixture into a prefabricated mould, and embedding a copper mesh serving as an electrode into a concrete wall; the mesh size of the copper mesh is 2.0 multiplied by 2.0mm2And the two copper nets are symmetrically embedded in the position 20mm away from the boundary of the concrete unit along the height of the sample after being polished, and the copper nets extend out of the boundary 20mm of the side surface of the concrete unit to serve as connector lugs of the energy collecting circuit.
5) And (3) after the module is formed, standing for 2 days in an environment with the room temperature of 20 +/-5 ℃ and the relative humidity of more than 50%, removing the module, putting the module into a standard curing box for curing for 28 days, taking out the module, putting the module into an oven, and drying for 2 days at the temperature of 80 ℃ to dry the residual water in the graphene-concrete composite material module.