Why can’t we put solar panels in the desert?
Our study this time is about the utilization of solar energy in the Gobi.
We found that: the current utilization of solar energy is mostly photoelectric conversion or photothermal conversion, mostly for the utilization of solar panels. However, the cost of solar panels is too high, and most of them are concentrated to supply power for a certain project, which is not suitable for being widely used by residents in the Gobi. Therefore, we intend to study new and cheap solar energy according to the characteristics of desert areas with sufficient sunshine, dryness and little rain. Convert machines and apply them to ordinary residents.
Why can’t we put solar panels in the desert? Basic information of the subject research:
1. Background: climatic conditions and environment of the Gobi
( 1 ) Formation of the Gobi
Scientists believe that since 2 million years, especially in the middle, late and Cene epochs since hundreds of thousands of years, the terrain in western China has continued to rise, and the climate has gradually become drier .
Climate zones are constantly expanding. The relatively loose rock bodies such as sandstone, silty mudstone and glutenite deposited on the surface of these zones are continuously weathered and denuded under the action of the sun and wind, turning into a large amount of clastic material. This mixed-sized detrital material disintegrated from the mountain and began to accumulate at the foot of the mountain. Under the action of floods, it was washed to the distant foothills, forming a large area of alluvial plains. During the dry season, under the action of strong winds, the fine sand and dust in the detrital material on the alluvial plain are blown into the sky, and the dust is blown to the area thousands of miles away, forming the Loess Plateau; and those fine sands are It is carried to the vicinity by the wind, forming a desert.
The gravel with a relatively large particle size was left in place, forming the current Gobi Desert landform. The Gobi is a desert terrain covered with hard soil layers of coarse sand and gravel . According to the origin, the gravel Gobi can be divided into three types: weathered, water-formed and air-formed. The main reason for its formation is due to fluvial flooding.
When a flood occurs, especially in a mountainous area, due to the gradual weakening of the energy of the flood, the following landform features are formed in the flood-impacted area: large pieces of rock are accumulated at the mountain pass closest to the mountain, and the rocks gradually become smaller toward the outside of the mountain; It is a rock the size of a fist to the size of a finger. Due to the erosion of the sun, rain and strong wind over the years, the edges and corners are gradually rounded and become what we call a stone (scientific name is gravel). In this way, the Gobi Desert was formed. And those finer sand and mud were alluvial and floated farther, forming the great desert farther away.
Why can’t we put solar panels in the desert? Climate of the Gobi
|Chinese name||temperate desert climate||Performance||Extremely dry, cold winters, hot summers|
|endemic animals||camels, desert foxes, sand snakes, etc.||explain||Climate of desert regions in the hinterland of temperate continents|
|endemic plants||Hu Yang et al||Typical area||Central Asia and China Tarim Basin|
There are many sunny days, strong sunshine, dryness, hot summer, large temperature difference between day and night, and a lot of wind and sand . The average relative humidity in desert areas is only about 20%, and it is often lower than 10% in the afternoon. Occasionally, in the weather records, 0% records are also found.
(3) Humanistic environment
At present, my country’s population is densely located in the southeast of Mohe-Tengchong, and we are more and more aware of the pressure brought by the continuous growth of the population in all aspects. However, the area with few people in the northwest is the vast Gobi, which is not suitable for human habitation. The Black Gobi can also be mined; some areas have oil, natural gas and other resources… and the oil and gas exploration in Xinjiang is also progressing very fast, and it will be exhausted within a period of time.
Leaving aside oil and gas for the time being, what should we do after the black Gobi is used and the still vast White Gobi? Can it be used? Can some people be moved next door? Furthermore, the characteristics of the Gobi area have been introduced above, so we intend to develop an invention that can effectively utilize the abundant solar energy in the Gobi, provide energy for human beings there, and play a role in promoting the migration of the population.
At the same time, environmental pollution has become more and more serious, and relocating part of the population is conducive to better solving environmental problems. This also requires clean energy sources, and solar energy is obviously the first choice .
2. Research status at home and abroad : the application of solar energy – solar panels
A solar cell, also known as “solar chip” or “photovoltaic cell”, is an optoelectronic semiconductor sheet that uses sunlight to generate electricity directly. As long as it is illuminated, it can output voltage instantly and generate current in the presence of a loop. In physics, it is called solar photovoltaic. There are two ways of solar power generation, one is light-heat-electricity conversion, and the other is light-electricity direct conversion.
|light-heat-electricity conversion||light-to-electricity direct conversion|
|The light-heat-electricity conversion method generates electricity by utilizing the thermal energy generated by solar radiation. Generally, the solar collector converts the absorbed thermal energy into steam, and then drives the steam turbine to generate electricity. The former process is the light-heat conversion process; the latter process is the heat-electricity conversion process, which is the same as ordinary thermal power generation. The disadvantage of solar thermal power generation is low efficiency and high cost. It is estimated that its investment is at least 5 to 10 times more expensive than that of ordinary thermal power plants. A 1000MW solar thermal power station requires an investment of 2 billion to 2.5 billion US dollars, and the average investment of 1kW is 2000 to 2500 US dollars. Therefore, it can only be applied to special occasions on a small scale, while large-scale utilization is economically uneconomical and cannot compete with ordinary thermal power plants or nuclear power plants.||Solar cells generate electricity based on the optoelectronic properties of specific materials. When these rays strike different conductors or semiconductors , the photons interact with free electrons in the conductors or semiconductors to generate an electric current. The shorter the wavelength of the ray, the higher the frequency, the higher the energy it has. For example, the energy of ultraviolet rays is much higher than that of infrared rays. But not all wavelengths of ray energy can be converted into electricity. Solar cell power generation is a renewable and environmentally friendly way of power generation. No greenhouse gasses such as carbon dioxide will be generated during the power generation process, and it will not pollute the environment. To put it simply, the principle of solar photovoltaic power generation is to use solar cells to absorb sunlight with a wavelength of 0.4 μm to 1.1 μm (for silicon crystals) and directly convert light energy into electrical energy output. Since the electricity generated by solar cells is direct current, if you need to provide power to household appliances or various electrical appliances, you need to install a direct/AC converter and replace it with alternating current, so that it can supply electricity for household or industrial use.|
The basic characteristics of solar cells are the polarity of solar cells, the performance parameters of solar cells, and the volt-ampere characteristics of solar electric environmental protection cells. The specific explanation is as follows:
|Polarity of solar cells||Silicon solar cells are generally made of P+/N-type structure or N+/P-type structure, P+ and N+, represent the conductivity type of the semiconductor material on the front side of the solar cell; N and P, represent the conductivity type of the semiconductor material on the backside of the solar cell . The electrical properties of a solar cell are related to the properties of the semiconductor material used to make the cell.|
|Performance parameters of solar cells||The performance parameters of solar cells are composed of open-circuit voltage, short-circuit current, maximum output power, fill factor, and conversion efficiency. These parameters are indicators to measure the performance of solar cells.|
|Volt-Ampere Characteristics of Solar Cells||A PN junction solar cell consists of a shallow PN junction formed on the surface, a front-side ohmic contact with stripes and fingers, a backside ohmic contact covering the entire back surface, and an anti-reflection layer on the front side. When the cell is exposed to the solar spectrum, photons with energies less than the band gap Eg do not contribute to the cell output. Photons with energy greater than the band gap Eg will contribute energy Eg to the battery output, and energy greater than Eg will be consumed in the form of heat. Therefore, in the design and manufacture of solar cells, the influence of this part of the heat on cell stability, life, etc. must be considered.|
3. Research objectives: (1) The cost is so low that an ordinary resident can accept it. (2) Effective use of solar energy
4. Research content:
(1) About solar energy
Solar energy refers to the thermal radiant energy of the sun (see the three ways of thermal energy transmission), and its main manifestation is what is often called the sun’s rays. Solar energy is produced by the fusion of hydrogen and helium atoms inside the sun to release huge nuclear energy, which is the radiation energy from the sun. The vast majority of human energy needs come directly or indirectly from the sun.
The average solar radiation intensity in Earth orbit is 1,369w/㎡.
The circumference of the Earth’s equator is 40,076 kilometers , so it can be calculated that the energy obtained by the Earth can reach 173,000 TW. The standard peak intensity at sea level is 1kw/m2, and the annual average radiation intensity of a point on the earth’s surface for 24 hours is 0.20kw/㎡, which is equivalent to 102,000TW of energy. (1TW=10 12 W) Although the energy radiated by the sun to the earth’s atmosphere is only 1/2.2 billion of its total radiation energy, it is as high as 173,000TW, which means that the energy that the sun irradiates on the earth per second is equivalent to 5 million tons of coal, the energy that irradiates the earth per second is 499,400,00,000 joules.
The wind energy, water energy, ocean temperature difference energy, wave energy and biomass energy on the earth all come from the sun. Solar energy is both primary energy and renewable energy. It is rich in resources and can be used free of charge without transportation and without any pollution to the environment. The widespread use of solar energy will create a new form of life for human beings, enabling society and human beings to enter an era of energy conservation and pollution reduction.
|Universal and harmless : the sun shines on the earth, without geographical restrictions , no matter on land or sea, no matter in mountains or islands, everywhere, it can be directly developed and used, easy to collect, and does not need to be mined and transported ; the development and utilization of solar energy will not pollute The environment, which is one of the cleanest energy sources, is extremely important in today’s increasingly serious environmental pollution .||Dispersion: The total amount of solar radiation reaching the Earth’s surface, although large, has a low energy flux density. Therefore, in order to obtain a certain conversion power when using solar energy, a set of collection and conversion equipment with a considerable area is often required, and the cost is relatively high.|
|resources: The solar radiation energy reaching the earth’s surface every year is equivalent to about 130 trillion tons of coal, and its total amount is the largest energy that can be developed in the world today.||Instability: Due to the limitations of natural conditions such as day and night, seasons, geographic latitude and altitude, and the influence of random factors such as sunny, cloudy, cloudy, and rainy, the solar irradiance reaching a certain ground is both intermittent and It is extremely unstable, which increases the difficulty for the large-scale application of solar energy. In order to make solar energy a continuous and stable energy source, and finally become an alternative energy source that can compete with conventional energy sources, the problem of energy storage must be well solved, that is, the solar radiation energy during the sunny day should be stored as much as possible for nighttime or rainy weather. However, energy storage is also one of the weaker links in solar energy utilization.|
|Long-term: According to the estimation of the rate of nuclear energy generated by the sun, the storage of hydrogen is enough to last for tens of billions of years, and the lifespan of the earth is about several billion years. In this sense, it can be said that the energy of the sun is inexhaustible .||Low efficiency and high cost: The development level of solar energy utilization, some aspects are theoretically feasible and technically mature. However, some solar energy utilization devices have low efficiency and high cost, and the current laboratory utilization efficiency does not exceed 30%. In general, the economy cannot compete with conventional energy sources. For a considerable period of time in the future, the further development of solar energy utilization will be mainly restricted by economics.|
(2) External combustion engine
The external combustion engine is a closed-cycle reciprocating piston heat engine with external combustion, which is different from the internal combustion engine which relies on the combustion of fuel inside the engine to obtain power. The fuel is continuously burned in the combustion chamber outside the cylinder, and is passed to the working medium through the heater. The working medium does not directly participate in the combustion, nor is it replaced.
Reciprocating piston heat engine.
The heat engine can use hydrogen, nitrogen, helium or air as the working fluid, according to the working principle of the Stirling cycle . A certain volume of working medium is filled in the closed cylinder of the hot air engine. One end of the cylinder is a hot chamber and the other end is a cold chamber. The working fluid is compressed in the low-temperature cold chamber, and then flows into the high-temperature hot chamber for rapid heating. The expansion work fuel is continuously burned in the combustion chamber outside the cylinder and passed to the working fluid through the heater. The working fluid does not directly participate in the combustion, nor is it replaced. .
According to the composition of the cycle in the cylinder, there are mainly two types of hot gas engines: gas distribution piston type and double-acting type. The gas distribution piston type hot air engine has two pistons in a cylinder making regular relative motions. The cold cavity and the hot cavity are connected by a cooler, a regenerator and a heater. The gas distribution piston pushes the working medium in the hot and cold cavity.
There is a back-and-forth flow between them; a double-acting heat engine has only one piston in each cylinder, which also functions as a gas distribution piston and a power piston. The upper part of each cylinder is the hot chamber and the lower part is the cold chamber. Each hot cavity is connected with the lower cold cavity of the adjacent cylinder through a heater, a regenerator and a cooler to form a power unit.
Thermodynamic cycle can be divided into four processes: constant temperature compression process, constant volume heat recovery process, constant temperature expansion process, and constant volume heat storage process. (  The cycle process is: ①Isothermal endothermic heating; ②Isothermal heating by external heat source; ③Isovolumic heat release for endothermic use; ④Isothermal release of heat to the cold body to complete a cycle. )
Why can’t we put solar panels in the desert? Advantages and Disadvantages of Stirling Engines
Since the external combustion engine avoids the detonation work problem of the traditional internal combustion engine, it achieves high efficiency, low noise, low pollution and low operating costs . External combustion engines can burn various combustible gasses, such as natural gas, biogas, petroleum gas, hydrogen, coal gas, etc., as well as liquid fuels such as diesel and liquefied petroleum gas, as well as wood and solar energy. As long as the thermal cavity reaches 500 ℃ , the equipment can perform power operation.
The lower the ambient temperature , the higher the power generation efficiency. The biggest advantage of the external combustion engine is that its use is not affected by the size of the air pressure (for an internal combustion engine, low air pressure will affect the intake air), which is very suitable for use in high altitude areas. And we use the sun as the heat source, it is impossible to put the sun into the internal combustion engine, after a lot of analysis, screening, calculation… We finally chose the external combustion engine.
However, Stirling engines still have many problems to solve, such as heat loss is 2-3 times that of internal combustion engines, etc. Therefore, it cannot become a mass-use engine.
Since the heat source comes from the outside, it takes time for the engine to respond to changes in heat applied to the cylinders (it takes a long time to conduct heat through the cylinder walls to the gasses inside the engine). this means:
1 > . The engine needs time to warm up before providing effective power.
2 > . The engine cannot change its power output quickly.
It has been reported that the Stirling engine has been used on the cooling fan of the computer motherboard, and the Stirling engine is driven by the heat of the north bridge chip to cool the hardware. The research is still in the research stage.
Compared with the internal combustion engine, the advantages of the heat engine are:
Applicable to various energy sources, whether it is liquid, gaseous or solid fuel, almost any high-temperature heat source (solar radioisotopes and nuclear reactions, etc.) can be used when indirectly heated by a heat-carrying system (such as a heat pipe), while the engine itself ( Except for the heater) no changes are required. At the same time, the hot air engine does not need to be pressurized by a compressor, and a general fan can meet the requirements and allow the fuel to have a high impurity content.
When the hot gas engine is running, since the fuel is continuously burned in the combustion chamber outside the cylinder, the working medium independent of the gas absorbs heat through the heater and performs external work according to the Stirling cycle, thus avoiding the knocking work and intermittent combustion similar to the internal combustion engine. process, resulting in efficient, low-noise and low-emission operation. High efficiency: the total energy efficiency reaches more than 80%; low noise: the noise floor of the bare metal at 1 meter is 68dBA.
The single unit capacity of the heat generator is small, and the unit capacity is from 20 to 50kw, and the system capacity can be increased or decreased according to local conditions. The structure is simple, the number of parts is 40% less than that of the internal combustion engine, the room for price reduction is large, and the maintenance cost is also low. [
(3) Fresnel lens
The Fresnel lens is mostly a thin sheet made of polyolefin material. One side of the lens surface is smooth, and the other side is engraved with concentric circles from small to large.
Fresnel lens, also known as threaded lens, is mostly a thin sheet made of polyolefin material, and also made of glass . One side of the lens surface is smooth, and the other side is engraved with concentric circles from small to large. Its texture is designed according to light interference, interference radiation, relative sensitivity and receiving angle requirements. Lenses are very demanding. A high-quality lens must have a smooth surface, clear texture, and its thickness varies with the application, mostly around 1mm. The characteristics are large area, thin thickness and long detection distance.
Fresnel lens vs ordinary convex lens
convex lenses of infrared and visible light in many cases , and the effect is better, but the cost is much lower than that of ordinary convex lenses. It is mostly used in occasions that do not require high precision, such as slide projectors, film magnifiers, infrared detectors , etc.
When using ordinary convex lenses, the corners will be darkened and blurred. This is because the refraction of light only occurs at the interface of the medium. The convex lens sheet is thicker, and the part where the light travels in a straight line in the glass will attenuate the light. If you can remove the straight-line propagating part and keep only the curved surface where the refraction occurs, you can save a lot of material and achieve the same light-gathering effect. The Fresnel lens is based on this principle.
The Fresnel lens looks like a piece of glass with numerous concentric circles (that is, Fresnel strips), but it can achieve the effect of a convex lens. If the projection light source is parallel light, the brightness of the image can be kept consistent after the convergent projection. .
The Fresnel lens has two functions: one is focusing, that is, the pyroelectric infrared signal is refracted (reflected) on the PIR, and the second is to divide the detection area into several bright areas and dark areas, so that the detection area can enter the detection area. A moving object can produce a changing pyroelectric infrared signal on the PIR in the form of a temperature change.
A Fresnel lens simply means that there are equidistant tooth patterns on one side of the lens, through which the light bandpass (reflection or refraction) of a specified spectral range can be achieved. Bandpass optical filters for traditional polished optics are expensive to manufacture. Fresnel lenses can greatly reduce costs.
The cost of a square meter of Phineer lens is only a hundred dollars. In order to highlight its “contribution” in terms of cost, for example, an optical lens that achieves the same effect costs 500,000 yuan! By choosing it, the cost of invention is greatly reduced.
3.1 What is a Fresnel lens
Fresnel lens application
The Fresnel lens was invented by the French physicist Augustin Fresnel , who originally used this lens design in 1822 to build a glass Fresnel lens system – the lighthouse lens .
A Fresnel lens is an optical element with a fine structure, which looks like a dartboard from the front and consists of concentric circles with one ring and one ring.
3.2 Basic principles
The way it works is very simple: Assuming that the refracted energy of a lens occurs only at the optical surface (eg, the lens surface), remove as much optical material as possible while preserving the curvature of the surface.
Another understanding is that the continuous surface portion of the lens “collapses” into a plane. In section, its surface consists of a series of zigzag grooves, and the central part is an elliptical arc. Each groove has a different angle from the adjacent groove, but all focus the light in one place to form a central focus, which is the focal point of the lens. Each groove can be regarded as an independent small lens, adjusting the light into parallel light or concentrated light. This lens is also able to eliminate some spherical aberrations.
(4) Insulation material
Thermal insulation materials are all substances with high porosity, because they have many holes, so they are very light, and the air in the middle of the holes has low thermal conductivity, so it plays a role in thermal insulation. However, it is not that the greater the porosity, the better the thermal insulation performance. First, when the pores are open, the air will exchange heat with the external solution, and the thermal insulation performance will decrease; second, when the porosity exceeds a certain range, the cavity of the porosity becomes larger, and the internal air travels. convection. We all know that convection heat transfer is much greater than radiation heat transfer, and at this time, the thermal conductivity also declines.
Why can’t we put solar panels in the desert?
1. Enamel inner tank, the enamel on the surface of the inner tank is non-metallic material, no rust, anti-corrosion, thick steel plate as the tank body, has strong pressure resistance, among which the high-glazed clad steel inner tank has the best anti-corrosion and heat preservation performance , longer life.
2. Insulating material (Insulating material), gas adsorption material (Getter) and composite film (Barrier) with high barrier properties in the core. Since the vacuum insulation panel can effectively avoid the heat transfer caused by air convection, the thermal conductivity can be greatly reduced to less than 0.005w/mk. It is the most advanced and efficient thermal insulation material in the world.
It’s like putting a “down jacket” on the outside of the engine.
This invention of ours creatively combines the Stirling engine with the Phineel lens for personal use, and in order to improve the working efficiency of the Stirling engine, thermal insulation materials are also added . Its thermal efficiency is higher than other methods, and the cost is much lower than other methods, and it is also suitable for personal use.
We are going to build a cover with a Fernier lens , so that the focus is on the heating part of the external combustion engine, and it can receive sunlight at any angle. Insulation materials are installed around the engine, and some auxiliary parts of it can be designed at the same time , such as: (1) adding an electric coil, a magnetic field source, and a transformer to become a small household generator; (2) adding a transmission device composed of gears and conveyor belts, Its mechanical energy can be used directly.
Application: (core: release mechanical energy, utilize mechanical energy)
(1) Parallel use can be used for water and sand transportation projects
(2) Household power supply in the Gobi area
(3) Households without electric fans
3. Research methods: (1) Literature method; (2) Experimental method; (3) Observation method (4) Analysis method
4. Research significance: It is more helpful for solar energy to enter the Gobi households, and at the same time, it is more helpful for the land use and development of the Gobi area.
(1) Use Stirling engine with Fresnel lens, and add thermal insulation system;
(2) Compared with other solar energy conversion methods, our move is cheaper and more efficient. And it is conducive to its promotion in the crowd.
(3) Setting its scope of application in the Gobi region will help reduce the pressure on land resources.
(4) A cover is set up with a Fernier lens , so that the focus is on the heating part of the external combustion engine, which can receive sunlight at any angle. And can be matched with thermal insulation materials to reduce heat loss.
(5) Add multiple accessories, multi-purpose.
6. Expected results : research report, ppt, device model.
2. Research process:
1. Determine the theme stage : March 30
At first, we listened to Mr. Li Xin’s explanation on topic selection, and then started to determine the research topic.
We identified the region as the Gobi area, because this area needs to be developed and lacks resources. The topic is mainly related to mechanical applications, and it was decided to design and make a model of a solar energy conversion device, the specific intention has been shown in the abstract and keywords. After a day of discussions, we decided on the final theme on the morning of April 1, and started all-staff action to collect data and write reports.
2. Report writing stage :
This stage is relatively smooth, because writing reports is something we are good at. We also roughly thought about the production plan of the ppt.
The general content of the report was completed on the morning of July 1st. We decided to make the model the next morning, and revise and improve the report again on July 3rd, so that the entire research report is over and can be maintained in good condition. schedule.
3. On-the- spot investigation stage: On July 12, a 6-day study tour began, and a field trip was conducted in Gansu.
4. Model making stage : July 2, July 3
We applied to Mr. Chen Bo to enter the physics laboratory on July 2 to make a model of such a machine. This general process is shown in the experimental report. We encountered some difficulties during the production process, and we spent all day in the laboratory on the 2nd. Through this production, we have a better understanding of the characteristics of the device, broadened our horizons in the laboratory, and cultivated our own hands-on ability.
5. Display stage :
(1) July 18
After making the model and getting the results, we started to perfect the ppt of the original design and do the final presentation work. The theme of the display is still to introduce the model, show the model we made, let the engine rotate, and explain it in ppt. The expected presentation time will be 5 to 6 minutes.
(2) November 14
Show for the first-year students and take the lead. And introduced to the experts of “316” inspection.
(3) December 17
It was shown to the leaders in the “316” review stage, and it was well received.
3. Difficulties, problems and reasons existing in the research:
(1) Some seemingly simple devices are difficult to assemble and manufacture;
(2) The connection parts cannot be welded together.
(1) Subjective: Our hands-on ability is relatively weak.
(2) Objective: There is no gas welding device in the school.
4. Research experience:
Through this inquiry study, our understanding of mechanical engineering has been further deepened. We can design and make models based on the corresponding data, and provide some effective measures for the development of the Gobi area according to our own making. During the exploration, our thinking, research ability, and hands-on ability have also been greatly improved. This exploration is very valuable to us. I believe that in the future study and life, we will be better at discovering problems in life, and start to explore them, so as to make our own contributions to the development of society.
Why can’t we put solar panels in the desert? Appendix : 1. Experiment 2. Photos of the research process
Project experiment – the production of Stirling engine
1. Make a Stirling engine.
2. The use of thermal energy to drive the operation of the Stirling engine.
3. Practice the use of Stirling engines.
4. Investigate the structure of the Stirling engine
- Experimental principle:
The principle of the Stirling engine will not be repeated here, and it has been explained in detail in the previous article. Here are the contents of the production.
2. Experimental materials:
1. 3 cans – one for replacement cylinder, one for power cylinder, and one for bracket
2. 3 bicycle spokes (cap can slide) – make crankshaft
3. An empty toothpaste tube – make a flywheel cap
4. Disc – flywheel, support
5. One balloon – piston fitting
6. A pin – a tool
7. Wire 20 cm – rod
8. scotch tape – accessories
9. pliers – tools
10. Scissors – tools
11. Solder – Tools
12. drill – tool
13. ruler – tool
14. Compass – tool
15. Ballpoint refills – reinforcement
16. Steel ball – replacement piston
17. Iron sheet – interface, vent pipe
18. Foam Discs – Power Piston Parts
3. Experimental process:
1. Drill two holes symmetrically at 1cm to 2cm from the top of the can. Its diameter is slightly larger than the spoke diameter. Put some lube on.
2. Using the cans just now, pierce a hole with a compass (or a fine electric drill) at the center of the bottom end of the can. Meet the hole diameter that just goes through the spokes of the bike. Solder the bicycle spoke nipple at the center of the circle with solder – the bracket
3. Use the second can to drill holes as before so that the spokes can go down. Weld this can to the bottom of a can – replace the cylinder
4. Take the third can, cut half of it first, and then drill a hole with a diameter of 1cm more from the side of the other half at a distance of 2cm from the bottom – power cylinder
5. Bend the second spoke in six places so that the two rectangular structures are 90 degrees out of phase.
It must be ensured that the center of the first rectangular structure is facing the round opening at the bottom end of the bracket. (You can use the spokes to insert the ballpoint refill to make it thicker – crankshaft
6. Use the other two discs as replacement piston supports. Solder the center of the disc with solder and the second spoke – piston making
7. Cut the iron sheet and bend it into a U shape, and drill holes at the bottom end and both ends of the upper arm, so that the diameter of the hole just passes through the iron wire. Pass through a piece of iron (small) in the middle of the wire – connect the upper crankshaft
8. Roll the iron sheet into a small cylindrical hole, so that the diameter of the small hole is the same as that of the power cylinder. Drill the same holes in the replacement cylinder. Connect the two cylinders with iron sheets and solder them with solder – the breather pipe
9. Cut the balloon horizontally, put the cut balloon on the upper part of the power cylinder, place the foam plastic at the center of the circle, screw a screw in the center of the foam plastic, and wrap the wire around the interface between the screw and the foam plastic – the power piston
10. Connect it in the same way that the piston connects to the crankshaft – connect
11. Cut off the upper end of the empty toothpaste tube, take the upper end, insert the crankshaft into the toothpaste tube, remove the toothpaste cap, insert the disc into the mouth of the toothpaste tube, and screw on the toothpaste cap – flywheel
12. The iron stand, the alcohol lamp and the engine just assembled are connected – assembly
13. Light the alcohol lamp and observe the effect – conduct the test
14. Retain achievements + display of achievements
The general division of labor is as follows:
(1) Completed thesis: Gao Ce, Wang Chengran
(2) Preparing for the experiment: Li Chi-ting
(3) Audit experiment: Gao Ce
(4) Document preparation: Li Chi Hall (background), Gao Ce (insulation system)
(5) ppt production: Wang Chengran
(6) Topic selection: all staff
(7) Determine the topic: Gao Ce
(8) Model making: all staff