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#121
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RC Rocketry - Ready to Fly to Orbit
Electrochemical cells may be assembled into any variety of devices.
One such device is a flow battery. A flow battery is a rechargeable fuel cell in which an electrolyte containing one or more dissolved electroactive elements flow through an electrochemical cell that reversibly converts chemical energy directly to electricity. Additional electrolyte is stored externally, generally in tanks, and is usually pumped through the cell of the electrochemical reactor. Flow batteries are rapidly "recharged" by replacing the electrolyte liquid while simultaneously recovering the spent material for re-energization. In other words, a flow battery is just like an electrochemical cell, with the exception that the ionic solution (electrolyte) is not stored in the cell around the electrodes. Rather, the ionic solution is stored outside of the cell, and can be fed into the cell in order to generate electricity. The total amount of electricity that is generated depends on the size of the storage tanks. The hydrogen peroxide flow battery makes use of an electrochemical cell that produces electricity when exposed to hydrogen peroxide. The flow battery stores hydrogen peroxide outside the electrochemical cell which flows through the battery releasing oxygen and water. The water is stored in a separate tank and presented to the electrochemical cell again when electric energy is applied to the cell. This recharges the water into hydrogen peroxide by forcing the absorption of oxygen by the water to form hydrogen peroxide again. This may be used to create hydrogen peroxide fuel. In terms of energy to the wheels, total energy per litre of hydrogen peroxide used this way is greater than fossil fuels used in thermal engines. In space applications 3.78 kg of hydrogen peroxide may be reduced to oxygen used for breathing and water which is also consumed, while producing 1.5 kWh of electricity. Two litres of water required each day by a person in space releases 1.78 kg of oxygen. Since a person only needs 1 kg of oxygen a day this is 0.78 kg more than is needed. So, combining this with 0.29 kg of carbon to form 1.07 kg of CO2 in a carbon oxygen system releases 3.1 kWh of additional electrical energy. A total of all the oxygen and water needed by a person in space combined with 4.6 kWh per day (190 Watts averaged use) whilst consuming only 4.07 kg of materials. A sphere 301.2 mm in diameter, floating in space 1 AU from Sol intercepts 97.5 watts of solar energy. Covered with photocells possessing a 55% efficiency, four such tanks equipped with storage of spent reactants - LOX, CO2, H2O, provide a means for continuous long-term life-support. The Sun at 1 AU generates 8.3e-15 kg/sec/m2 of protons in the solar wind. Over the course of a year 262 micrograms of hydrogen passes through a square meter. When combined with 2,096 micrograms of oxygen from silicates this produces 2,358 micrograms - 2.358 mg - of water while releasing 1.834 milligrams of pure silicon. Over 1,000 years - of efficient conversion - this is 2.358 grams. 1 million years 2.358 kilograms - 424 million years - 1,000 kg! A cubic meter of water! On the planet Mercury, the rate of conversion would be 6.68x greater than at Earth! This 15.751 mg of water is produced in a year at Mercury. This explains why Mercury has ice caps! http://nssdc.gsfc.nasa.gov/planetary...e_mercury.html |
#122
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RC Rocketry - Ready to Fly to Orbit
On Monday, March 9, 2015 at 6:50:56 AM UTC-4, Fred J. McCall wrote:
Mookie, didn't anyone ever teach you that when you copy from another source you should credit that source. Failure to do so is usually called 'plagiarism'. Is plagiarism something you needed to learn a lot about in your life? William Mook wrote: Electrochemical cells may be assembled into any variety of devices. One such device is a flow battery. A flow battery is a rechargeable fuel cell in which an electrolyte containing one or more dissolved electroactive elements flow through an electrochemical cell that reversibly converts chemical energy directly to electricity. Additional electrolyte is stored externally, generally in tanks, and is usually pumped through the cell of the electrochemical reactor. Flow batteries are rapidly "recharged" by replacing the electrolyte liquid while simultaneously recovering the spent material for re-energization. In other words, a flow battery is just like an electrochemical cell, with the exception that the ionic solution (electrolyte) is not stored in the cell around the electrodes. Rather, the ionic solution is stored outside of the cell, and can be fed into the cell in order to generate electricity. The total amount of electricity that is generated depends on the size of the storage tanks. The hydrogen peroxide flow battery makes use of an electrochemical cell that produces electricity when exposed to hydrogen peroxide. The flow battery stores hydrogen peroxide outside the electrochemical cell which flows through the battery releasing oxygen and water. The water is stored in a separate tank and presented to the electrochemical cell again when electric energy is applied to the cell. This recharges the water into hydrogen peroxide by forcing the absorption of oxygen by the water to form hydrogen peroxide again. This may be used to create hydrogen peroxide fuel. In terms of energy to the wheels, total energy per litre of hydrogen peroxide used this way is greater than fossil fuels used in thermal engines. In space applications 3.78 kg of hydrogen peroxide may be reduced to oxygen used for breathing and water which is also consumed, while producing 1.5 kWh of electricity. Two litres of water required each day by a person in space releases 1.78 kg of oxygen. Since a person only needs 1 kg of oxygen a day this is 0.78 kg more than is needed. So, combining this with 0.29 kg of carbon to form 1.07 kg of CO2 in a carbon oxygen system releases 3.1 kWh of additional electrical energy. A total of all the oxygen and water needed by a person in space combined with 4.6 kWh per day (190 Watts averaged use) whilst consuming only 4.07 kg of materials. A sphere 301.2 mm in diameter, floating in space 1 AU from Sol intercepts 97.5 watts of solar energy. Covered with photocells possessing a 55% efficiency, four such tanks equipped with storage of spent reactants - LOX, CO2, H2O, provide a means for continuous long-term life-support. The Sun at 1 AU generates 8.3e-15 kg/sec/m2 of protons in the solar wind.. Over the course of a year 262 micrograms of hydrogen passes through a square meter. When combined with 2,096 micrograms of oxygen from silicates this produces 2,358 micrograms - 2.358 mg - of water while releasing 1.834 milligrams of pure silicon. Over 1,000 years - of efficient conversion - this is 2.358 grams. 1 million years 2.358 kilograms - 424 million years - 1,000 kg! A cubic meter of water! On the planet Mercury, the rate of conversion would be 6.68x greater than at Earth! This 15.751 mg of water is produced in a year at Mercury. This explains why Mercury has ice caps! http://nssdc.gsfc.nasa.gov/planetary...e_mercury.html |
#123
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RC Rocketry - Ready to Fly to Orbit
The solar wind can be mined by a space colony for hydrogen. Ancient hydrogen can also be mined. Since some of the solar wind has been captured by processes in the solar system which result in significant water reserves in the most unusual places.
The present thinking among some astronomers is that dry asteroids over billions of years accumulate massive quantities of water through the reaction of this hydrogen source the solar wind with oxides on the asteroids and moons. This leaves reduced metals at the bottom of substantially deep oceans. The 200 km deep ocean covered with 50 km of ice on Ceres the 100 km deep ocean on Europa covered by 50 km of ice, Callisto's 300 km deep ocean beneath 80 km of ice, Saturn's moon Enceladus 500 km diameter ice ball.. all have volumes of water equal to or greater than all the Earth's oceans. Which given their low gravity wells, essentially solves the problem of building space colonies that support a biosphere. Low-cost abundant space access. https://www.startjoin.com/updates/project/FirstLuna/788 Consider a 20 kg spherical unit 301.2 mm in diameter that consists of 16.1 kg of hydrogen peroxide and 2.3 kg of kerosene along with 1.6 kg of structure, equipped with a MEMS based propulsive skin, along with a tetrahedral positioned connector system that is capable of passing propellants and signals to neighbouring units to operate collectively, made in mass quantities, forms the basis of a new sort of space launcher. The sphere also possesses a hydrogen peroxide/kerosene fueled flow battery along with 36 cameras of 3 megapixels each and three inertia wheels. The Panoramic camera system matches star positions to determine precise orientation in space down to 1/50th arcminute With an exhaust velocity of 3.17 km/sec - a single unit achieves 8.00 km/sec. Two units operating together places one unit into LEO, with recovery of both units at the launch centre. Stacked in a Face Centered Cubic (FCC) lattice; http://upload.wikimedia.org/wikipedi..._camerea. jpg You can see that three layers, consisting of 14 spheres can send one sphere to soft land on the moon, or Mars. Four layers consisting of 30 spheres are capable of sending a sphere to the moon and back, or to Mars and back. Larger stacks are capable of more. Layers Area Total dV-km/sec 1 1 1 8.0066 2 4 5 12.5940 3 9 14 15.5812 4 16 30 17.7994 5 25 55 19.5653 6 36 91 21.0330 7 49 140 22.8522 8 64 204 23.9685 9 81 285 24.9686 Self replicating nanobots don't weigh much. Large numbers of them are placed into small nodules built into the skin of each sphere - http://news.nationalgeographic.com/n..._robots_2.html which is prototyped on the micro-scale by Electrolux's MAB https://www.youtube.com/watch?v=a3j4y6uJQmg The swarming robots collect solar energy and pull apart materials one atom at a time. They then determine what the atom is by shaking it to determine its charge to weight ratio, and then put it in an appropriate atomic channel for storage, to be retrieved during build cycle. The build cycle consists of building more swarming robots - which are then programmed to self assemble into any variety of product. In this way, 15,000 joules of sunlight is collected for each gram of raw material processed into nanobots. Lets consider the inner planets and Ceres along with Europa. http://upload.wikimedia.org/wikipedi...comparison.jpg http://photojournal.jpl.nasa.gov/jpeg/PIA08400.jpg Body AU W/m2 Time Diam. Qwatts km/sec MJ/kg gigatons/yr hours Mercury 0.39 9,132.55 47.78 4879 93.91 11.0 75.5 39,252.1 0.61 Venus.. 0.72 2,615.14 166.86 12104 165.50 12.0 87.0 60,033.0 2.26 Moon.. 1.00 1,368.00 318.98 3475 7.14 3.8 22.2 10,134.6 4.00 Mars.. 1.52 589.47 740.27 6792 11.75 7.0 39.5 9,384.6 9.67 Ceres. 2.77 178.29 2,447.50 510 0.02 4.3 24.2 26.1 26.90 Europa 5.29 48.88 8,926.35 1800 0.07 6.8 38.1 56.6 107.14 A total of 118,887.1 gigatons per year. Each square meter of nanobot based solar collector masses 16 grams using current technology. The distance from the sun in Astronomical Units (AU) of each planet or moon, or dwarf planet, determines the power level at that location. This gives a replication time in seconds. The diameter of the planet determines the number of watts received. Qwatts is quadrillions of watts. Humanity currently generates 0.017 QWatts. The speed at which something must be projected from the surface of each place to reach Earth is given in km/sec. This speed gives the minimum energy required which when added to the energy required to extract and make things, gives a total energy needed to return a kg of material to Earth this is given in MJ/kg. Dividing this figure into the amount of energy available obtains the mass flow rate possible to Earth - this is given in terms of gigatons per year. The replication time and surface area determine the number of hours it takes after landing to establish a planetary production system capable of this rate of production. In the hard Science Fiction Novel, Rendezvous with Rama, Arthur Clarke imagines a large O'Neill type cylinder, capable of interstellar flight. It has the following statistics; Exterior/Overall Interior Length ~54 km ~50 km Diameter ~20 km ~16 km Area ~4000 km2 ~2500 km2 Volume ~17000 km3 ~10000 km3 Mass ~1e16 kg (10,000 gigatons) The average density of the shell is 1,428 kg/m3. The two kilometer thickness of the shell provides substantial radiation shielding making it suitable for Interstellar flight. Such a cylinder is possible to build with the technology described here. At 10,000 gigatons per ship we're talking about a capability of assembling one ship like this every month for thousands of years. Each ship is 2500 sq km in area. With a population density equal to that of Monaco, (18,475 people/km2)a total of 46.18 million persons per month could be housed in these ships. 554.25 million people per year could leave Earth permanently. With 7.14 billions and a population growth rate of 1.12% per year, and 12 of these ships arriving every year, we can calculate the following table; Year Terrestrial Off-World Units Population/Unit 2020 7,140.00 0.00 0 0.00 2021 6,665.72 554.25 12 46.19 2022 6,186.12 1,114.71 24 46.45 2023 5,701.16 1,681.44 36 46.71 2024 5,210.76 2,254.52 48 46.97 2025 4,714.87 2,834.03 60 47.23 2026 4,213.43 3,420.02 72 47.50 2027 3,706.37 4,012.57 84 47.77 2028 3,193.63 4,611.76 96 48.04 2029 2,675.15 5,217.66 108 48.31 2030 2,150.86 5,830.35 120 48.59 2031 1,620.70 6,449.90 132 48.86 2032 1,084.60 7,076.39 144 49.14 2033 542.50 7,709.90 156 49.42 2034 500.00 7,838.75 168 46.66 2035 500.00 7,932.14 180 44.07 2036 500.00 8,026.58 192 41.81 2037 500.00 8,122.08 204 39.81 2038 500.00 8,218.64 216 38.05 2039 500.00 8,316.29 228 36.47 2040 500.00 8,415.04 240 35.06 2041 500.00 8,514.88 252 33.79 2042 500.00 8,615.85 264 32.64 2043 500.00 8,717.95 276 31.59 2044 500.00 8,821.19 288 30.63 2045 500.00 8,925.59 300 29.75 2046 500.00 9,031.15 312 28.95 2047 500.00 9,137.90 324 28.20 2048 500.00 9,245.85 336 27.52 2049 500.00 9,355.00 348 26.88 2050 500.00 9,465.38 360 26.29 A 2.5 hour sun synchronous orbit in a sunrise-sunset orbit 3,000 km above the Earth hold 2,942 such ships at a single altitude. At the rates possible using sunlight alone as the energy source, it takes 245 years to fill a single altitude with these ships. |
#124
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RC Rocketry - Ready to Fly to Orbit
Of course, at 15,000 joules per gram processing energy for materials, and 40,000 to 60,000 joules per gram to transport materials from a distant planet in the solar system to the Earth's surface (or Earth orbit) - we can see that its four times more efficient to find and process materials on Earth!
A ballistic transport from any spot on Earth to any other requires no more than 30,000 joules per gram. Each square meter of self-replicating nanobot based solar collector masses 16 grams using current technology. The power level at Earth averages 250 Watts/m2. This gives a replication time of 1746 seconds - about 29 minutes - or one half hour. The diameter of Earth determines the maximum number of watts received. For Earth and this technology the limit is 70 Qwatts or 70 quadrillions of watts. Humanity currently generates 0.017 QWatts. The speed at which something must be projected from the surface of each place to reach any other place on Earth is less than orbital velocity 7.9 km/sec. This speed gives the minimum energy required which when added to the energy required to extract and make things, gives a total energy needed to supply a kg of material to anyone anywhere on Earth this is less than 30 MJ/kg. Dividing this figure into the amount of energy available obtains a mass flow rate possible for Earth - this is 73,634 gigatons per year. About 10,000 metric tons per person per year. The replication time and surface area determine the number of hours it takes after construction of the first nanobot to establish a planetary production system capable of this rate of production. 16 grams of self replicating cells grows to cover the entire Earth in 24 hours. At present, the wealthiest of us consume less than 10 metric tons per year. Supplying this must wealth for all persons requires only 1/10,000th of the Earth's surface be transformed with self-replicating machinery. A circular area over a shallow region of the Earth's ocean that is 255 km in diameter supplies all the needs of 8 billion millionaires whilst cleaning up the mess left by more primitive technologies. |
#125
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RC Rocketry - Ready to Fly to Orbit
Hydrogen peroxide is produced by electrolytic action
http://link.springer.com/article/10....8221369#page-1 When combined with a high intensity photocell - operating in a water/oxygen solution produces hydrogen peroxide. It is therefore feasible to consider a rechargeable flow battery consisting of hydrogen peroxide and water. A 2 litre bottle of hydrogen peroxide contains 2.9 kg of the material. Discharging a flow battery using this material reduces it to 1.366 litres and 1.366 kg of pure water with 1.534 grams of oxygen with the release of 1.2 kWh of electrical energy. A 2.88 square meter (1.2 m x 2.4 m) solar panel that is 55% efficient produces 1,584 watts of electrical power and when exposed to 3.6 hours per day generate 5.7 kWh/day. This charges 9.5 litres of hydrogen peroxide every 24 hours. Using 50% hydrogen peroxide to maintain stability, requires 19 litres every 24 hours. This is a layer of hydrogen peroxide 66 mm thick across a 1.2 m x 2.4 m area. Six panels, forming an area 4.8 m x 3.6 m may discharged continuously at 1.4 kW 24 litres - containing 69.6 kg of hydrogen peroxide can maintain a 1.2 kW power level for 24 hours. This is sufficient to supply a home. A Tesla S uses 85 kWh to recharge. 283.3 litres at 50% concentration stores this much energy - retrievable in electrical form. This is half the weight of the LiIon battery. Another six panels is sufficient to refill a Tesla S twice every 5 days - a dozen times a month. https://www.youtube.com/watch?v=w2itwFJCgFQ |
#126
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RC Rocketry - Ready to Fly to Orbit
On Monday, March 16, 2015 at 7:13:59 AM UTC-4, Fred J. McCall wrote:
Pure hydrogen peroxide is hideously dangerous and probably one of the last things you want around in a car crash... William Mook wrote: Hydrogen peroxide is produced by electrolytic action http://link.springer.com/article/10....8221369#page-1 When combined with a high intensity photocell - operating in a water/oxygen solution produces hydrogen peroxide. It is therefore feasible to consider a rechargeable flow battery consisting of hydrogen peroxide and water. A 2 litre bottle of hydrogen peroxide contains 2.9 kg of the material. Discharging a flow battery using this material reduces it to 1.366 litres and 1.366 kg of pure water with 1.534 grams of oxygen with the release of 1.2 kWh of electrical energy. A 2.88 square meter (1.2 m x 2.4 m) solar panel that is 55% efficient produces 1,584 watts of electrical power and when exposed to 3.6 hours per day generate 5.7 kWh/day. This charges 9.5 litres of hydrogen peroxide every 24 hours. Using 50% hydrogen peroxide to maintain stability, requires 19 litres every 24 hours. This is a layer of hydrogen peroxide 66 mm thick across a 1.2 m x 2.4 m area. Six panels, forming an area 4.8 m x 3.6 m may discharged continuously at 1.4 kW 24 litres - containing 69.6 kg of hydrogen peroxide can maintain a 1.2 kW power level for 24 hours. This is sufficient to supply a home. A Tesla S uses 85 kWh to recharge. 283.3 litres at 50% concentration stores this much e... Hydrogen peroxide is widely used throughout the world and is a common industrial product. The stability and safety of 70% hydrogen peroxide shipments are well established and is demonstrably no more dangerous than petrol, diesel fuel, av gas or jet fuel. http://www.car-accidents.com/2008-co...-uae-fog-1.jpg |
#127
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RC Rocketry - Ready to Fly to Orbit
The energy content I calculated was adjusted for varying concentration. You missed that point. That's not an issue here.
The safety figures for petrol vs. hydrogen peroxide are based on the number of deaths per MJ of the material shipped. This is the figure of merit used by insurance companies in determining rates for shippers. By this measure hydrogen peroxide is vastly safer than fossil fuels. As for non-meritorious claims of safety, which you suggest, why don't you drink 50 ml of a 30% solution of leaded petrol and I'll drink 50 ml of 30% solution of hydrogen peroxide and we'll see who comes out of that standing. On Monday, March 16, 2015 at 10:02:17 AM UTC-4, Fred J. McCall wrote: William Mook wrote: On Monday, March 16, 2015 at 7:13:59 AM UTC-4, Fred J. McCall wrote: Pure hydrogen peroxide is hideously dangerous and probably one of the last things you want around in a car crash... William Mook wrote: Hydrogen peroxide is produced by electrolytic action http://link.springer.com/article/10....8221369#page-1 When combined with a high intensity photocell - operating in a water/oxygen solution produces hydrogen peroxide. It is therefore feasible to consider a rechargeable flow battery consisting of hydrogen peroxide and water. A 2 litre bottle of hydrogen peroxide contains 2.9 kg of the material.. Discharging a flow battery using this material reduces it to 1.366 litres and 1.366 kg of pure water with 1.534 grams of oxygen with the release of 1.2 kWh of electrical energy. A 2.88 square meter (1.2 m x 2.4 m) solar panel that is 55% efficient produces 1,584 watts of electrical power and when exposed to 3.6 hours per day generate 5.7 kWh/day. This charges 9.5 litres of hydrogen peroxide every 24 hours. Using 50% hydrogen peroxide to maintain stability, requires 19 litres every 24 hours. This is a layer of hydrogen peroxide 66 mm thick across a 1.2 m x 2.4 m area. Six panels, forming an area 4.8 m x 3.6 m may discharged continuously at 1.4 kW 24 litres - containing 69.6 kg of hydrogen peroxide can maintain a 1.2 kW power level for 24 hours. This is sufficient to supply a home. A Tesla S uses 85 kWh to recharge. 283.3 litres at 50% concentration stores this much e... Hydrogen peroxide is widely used throughout the world and is a common industrial product. The stability and safety of 70% hydrogen peroxide shipments are well established and is demonstrably no more dangerous than petrol, diesel fuel, av gas or jet fuel. http://www.car-accidents.com/2008-co...-uae-fog-1.jpg You need to adjust all your reaction rates for using dilute H2O2. And no, it's not as safe as petrofuels. Concentrations above 68% are prone to spontaneous explosive decomposition if they get too warm. I'll tell you what. I'll put my hand in a pail of gasoline and you put your hand in the 'equally safe' pail of 70% hydrogen peroxide. Or perhaps you'd like to drop a cup of grease into your pail and I'll drop a cup of grease into mine. After all, they're 'equally safe', right? -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Dryden |
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