CaptainPanic

I think that sea water does not de-mix (or un-mix)... however, large amounts of fresh water on top of salt water might also not mix. I'd be curious if there is any article or other reference to suggest that salt water actually de-mixes when left at rest. That could be an interesting way to produce a perpetual motion device, as you can actually extract energy (electric) from two volumes of water with different amounts of salt.

In short, you go from 2 molecules to 4 molecules. Pressure is, in fact, just the amount of molecules per volume (regardless of the type of molecules!)... so if the amount of molecules doubles, then...

Hmm... funny how the other posts didn't show on my screen, and I really thought I was the 1st to reply to this one...

yes, if the solar panels get covered in dust during construction, then that's a problem. But after construction is complete, they will remain clean... there is no wind to carry the dust to the panels. I believe I heard a story that the the Russians (or rather the Soviets) placed some mirrors on the moon. Those are still reflective 30 or 40 years after. Try that with an earth based piece of glass. The angle of the solar panel is governed by the position of the sun, (or perhaps by the whims of the architect if they're placed on buildings... but let's assume that we just make a farm, so those things follow the sun). Rain is actually quite dirty at times. Most raindrops form around an aerosol. Fact is that solar panels need to be cleaned. Deserts can have dust storms. Ok, I chose my words a bit too strong. Fact is though that the regular silicon based solar cells (the ones we talk about here, the ones for which the materials are available on the moon) are less efficient at higher temperatures. Space based solar panels aren't the regular solar panels that are placed on roofs... I know quite little about those. You can calculate it yourself. I checked some internet sources for the Netherlands (the total built area, the total area for housing, the total electricity demand, the insolation (amount of sun received per day on average) and the average efficiency of solar cells). With those numbers, I arrived at the conclusion that we just need to fill 65% of the roofs of houses (offices and industry therefore not included) with solar panels to replace all electricity. If specifically asked for, I'll post the calculation in a separate thread. I don't believe in algae (yet). Most of the media attention focusses on the ridiculously high yields obtained in labs... 10% of the sun's energy converted into biomass or something. That will never be achieved in reality, simply because there are some limiting factors: oxygen is toxic at some point (needs to be removed). CO2 must be pumped into the water (using energy intensive turbines). The algae must be harvested, separated from water, dried. That all requires energy too. I saw many designs for closed systems (with transparent pipes) and I think they're all mad. The only algae technology I believe in are the open systems - bassins where CO2 comes from the air, and oxygen can go into the atmosphere. During growth, little or no energy is needed. No idea about those... but I have little against it. Personally, I am quite a big fan of the wind turbines. By now, I consider them proven technology. Biofuels can be an intermediate solution for the next 10 years (especially if we can put an end to the use of corn). ... but in the end, the energy crisis will only be solved if we stop population growth. That's the nasty conclusion... It's so nasty, because technology can do nothing about it.

You're nearly there. compared to a pure liquid, one component in a mixture has a lower vapor pressure because, as you put it, less molecules can escape the liquid (part of the surface is occupied by the 2nd component). But the molecules in the gas phase, each individually, still have an equal chance to hit the surface again - the surface of the liquid is the same size, although it may be occupied with several different molecules. In the "ideal case", the molecule that hits the surface and enters the liquid doesn't care about the type of molecules there. So, from those two facts, it's easy to find that this means that there are less molecules in the gas phase at any given time. This is simplifying it a bit, but it works.

We can build solar panels in situ on earth as well... and use them here, right where we need the energy. Seems easier to me? Some advantages that come to mind: - We have a large industrial infrastructure here on earth. - The energy is required here as well. - Maintenance is cheaper here (although admittedly, they get dirtier here as well, because of rain, wind, birds and dust). - Earth based solar panels receive free air-cooling, while lunar solar panels will just get toasted in the sun. Silicon based solar cells decrease in efficiency at higher temperatures. - There is plenty of space available to place solar cells on earth. The area required to substitute all our electricity by solar electricity is still not much more than all the space on the roofs of all buildings.

Logically, it should just be the weight of the water and the rock/mud/whatever that is on top of the oil/gas field. In addition, the chemicals present in the oil/gas have a vapor pressure at the temperature in the field. Finally, over the years, the pressure may have increased because of certain reactions... but only if the field is completely closed. Anticipating the next question: why does the oil come out of the well with such force? Because the weight of 1 mile sea, and another mile of rock is a lot more than a column of just 2 miles of oil. So, the static pressure inside the field is much more than the static pressure inside the well (inside the drilled hole that's now full of oil and gas)... and that pressure difference drives the oil out. Finally... when fields become empty, oil companies sometimes pump CO2 or water (possibly turning into steam) into a field on one end, to force the oil or gas out on the other end of the field. In that case, the pressure in the well is obviously artificially increased by pumps/turbines.

I'd be worried about insulation if you use the jigsaw pieces. If no air gets through then it may work. In a similar fashion, I'd be worried about insulation and comfort in the containers as well. A single brick wall with a roof on it is cheap enough. It's the double walls, the double glazing, large windows, spaceous kitchen and bathroom that make a house expensive. And of course, you still need some ground to build it on. Finally, I am not sure that the container city needs no foundation. In construction, a lot of time and money is spent on the foundation (especially in the Netherlands). Once the foundation is in place, the pre-fab concrete slabs make it easy to build quickly. Sorry for being a bit skeptical about the suggested ideas.

I agree with the above. Forget about using the CO2 for extra pressure. You can use it to heat the water though, if you run it through a tube through the water... But my main question is to Doctor Jones: what are you trying to show with your project?? - Efficiency of coal powered plants: your small scale, low temperature, low pressure system won't come near the efficiency of the large plants. You'll be lucky to get half the efficiency. Therefore, any comparison with other sources, using your own results, is difficult. - The workings of a coal powered plant are very simple. Essentially, it's just a steam engine without pistons, but with a turbine instead. The diagram here shows that there is a little more to it nowadays. There are 3 turbines (high, medium, low pressure). The steam is generated in many heat exchangers. The gas cleaning is ever more important. Research now focusses on turbine design (make them better), and the use of different fuels. It will work, but it won't be efficient. Pressure relief valve. It's a piece of kit that lets out the pressure if it gets too high. You're actually trying to do something that's more dangerous than you may think. Other stuff to add can be found in the same diagram I added above. Not really. Optimizing your coal powered plant is tricky. Try not to lose too much heat, make sure the water gets hot. And don't blow yourself up if the steam gets pressurized. Yes. But charcoal will be easier, and gives you the same results in the end. Coal will burn hotter, but that's only relevant if you're really looking at efficiency. I'd be surprised if you can measure the efficiency accurately enough, and if you approach the reality near enough for this to be relevant. Hotter = higher pressure. Be careful! Your question should simply be: what pressure do I want to achieve? The pressure is determined by the pressure drop of the turbine. Turbines are designed for certain pressures... and therefore your choice of turbine will determine the pressure. Then, once you know the pressure, you make sure that your drums and pipes have the the right thickness. Thicker = stronger. Steel should be ok... but make sure it cannot corrode too fast. If you intend to design the turbine yourself (good luck - that's really difficult), then I'd be surprised if you achieve any high pressure at all. Try to heat the water with the sun, using mirrors. That's essentially the same machine, but solar powered. Try Swagelok.com for all the pressurized piping you may need. Be warned, you're playing with expensive toys. Depends how big you want to make it. I've seen small steam engines that fit on a 30x30 cm area. Your limiting factor for size is the area you need for a decent fire. Gas fires can be a lot smaller (think if a lighter or a small cooking fire), and therefore it will be easier (smaller) to build a gas power plant. Good luck!

I think the first application of rail guns will be to shoot stuff into low orbit. I cannot see military applications anywhere soon... for the reasons mentioned above: military applications need mobile electrical power, and the rails wear too quickly. However, there is plenty of robust bulk material that needs to get into orbit (fuels, water, food, or mechanical parts for maintenance of ships up there)... if packed in the right way, all that can withstand massive G forces, so it can be launched in a simple shell. Cheap, efficient, fast.

I totally agree with you. It's much easier to simply change our sources of energy, and to make sure that the ice doesn't melt than to adapt and avoid the waters to rise. I don't wish to hijack the thread, but we've already accomplished to change the surface of nearly the entire land surface of the earth over the last 100 years. Is it really so hard to just change our energy sources? I think we're all overestimating the effort that is required. A second option is to protect the land. I'm a Dutchman, and we manage to live under the sea level for centuries already. The last option would be to move the water. If we move it, it would have to go to an underground storage, or at least a closed storage. Any bassin would have to be enormous to be able to significantly reduce the sea levels. It would have to be quite deep, and it needs a large surface area. In other words: it would alter the climate of Africa, Europe and Asia (and therefore of the world)... and it doesn't make much sense to change our climate in order to avoid climate change, does it? I conclude that this is a very bad idea. The comparison If we're really considering such costly and drastic measures as to create a large artificial sea, or space shuttles, or any other way to reduce the sea level rise, then we sure as hell should first reconsider to simply change our energy sources. Until now, the comparison in all the media is between fossil energy and sustainable energy, without any additional costs attached to the fossil energy. And fossil energy comes out cheapest, so we don't change our energy sources much. If we now start to compate fossil energy plus the construction of artificial seas and/or other drastic measures, and compare that to sustainable energy... well... then sustainable energy may just start to look really cheap suddenly.

It helps us if you ask a more specific question. Just a quick Google search got me this website. There are many more websites. What exactly do you need? We are not going to explain all the rules of fluid mechanics.

What surprised me about the video is that the room is full of skeptical people of the Technical university of Delft (a renowned university in the Netherlands). They did not dismiss this as 'bull' immediately. Perhaps the machine is not genuine - the movie does not give enough information to say something about that. But the professors and other university people present in the room (the audience) was most definitely genuine. These people were open minded, or even skeptical, and I haven't really seen an open dismissal of the machine as a fake. However, (I quote from the research institute's own website) : OTB Research Institute for the Built Environment specializes in independent research and consultancy in the field of housing, construction and the built environment. The institute is part of Delft University of Technology. Why did this guy choose this particular research institute if the faculty of Mechanical Engineering is literally the neighbor of this institute (I know that university quite well), and has plenty of people who would have loved to see this explained. I'd say that if you manage to demonstrate this in front of professors in mechanical engineering (who know thermodynamics very well), then you've passed the 'bull'-test. (Obviously, the conservation of energy will not be ignored - but possibly a natural phenomenon is used? there is plenty of electricity and magnetism out in nature).

I fear that you make a mistake here. While the moon orbits the earth in 27.32 days, the earth itself turns around its own axis once per day. So, that means that (rounding it off a little) the rotation is actually 360 degrees per day, or 15 degrees per hour. is a nice animation of what's going on. The circumference of the earth is about 40000 km. That means that the velocity of the earth's surface relative to the position of the end of the cable is about (40000/24 = ) 1650 km/hr. That's quite fast. The good part is of course that you can catch the elevator every day... as it passes along the same line every day. But I'm not sure I'd like to catch the space elevator as it whizzes past my town at several kilometers altitude at Mach 1.5 without stopping.

Before going into some details, a word of warning: the field of mass and heat transfer is a b*tch. It'll take some time to get used to. However, this doesn't mean you cannot play with a tank of water. Measurements can be tricky though. Evaporation is related to: - Surface area - Concentration gradient across the boundary - Mass transfer coefficient across the liquid/gas boundary Surface area Waves and droplets obviously increase your surface area. So, this is relevant. Concentration gradient You need to know the vapor pressure of the water (depends on the temperature - so you need to measure that all the time). You need to know the moisture already present in the air, and the air temperature as well. That's the gradient across the two bulk phases. Mass transfer coefficient You need to find out of the wind is blowing, and if so, if it is turbulent. Maybe there is "artificial wind" in the form of ventilation? If the water and air are not of the same temperature, then unfortunately for you, you are going to have heat transfer as well. It will cause the air to move faster, and therefore increasing the mass transfer too. You see, at the part of the mass transfer coefficient it becomes really tricky. Unfortunately, a little wind can be just as relevant as millions of droplets on the wall of your tank. At this point, I have talked enough. Time to listen again. Are you planning to do a measurement only - or do you need to develop a correlation or formula of some kind to describe what you measured?

http://www.streaming-madness.net/ That's the link. It has over 50 quality documentaries. Just wanted to share the link with you all... I just spent nearly my entire Sunday watching the latest progress in astronomy Personally, I especially enjoyed this one. Some criticism on the current theories (especially on the requirement of dark matter and dark energy to explain the universe). p.s. I am not connected to that website - this is no advertisement

Cool link. Thanks for that. The numbers you give make it sound like a very viable option for a car engine. However, the article also explains why steam power lost it against the internal combustion engine: The electric starter in combination with the internal combustion engine were entering the market around 1912 (introduced by GM). The efficient steam engine cars by Dobel entered the market only in 1924, at a price that was too high. They had something ready in 1917 / 1918 (model C - an unreliable car). Also interesting is the fuel consumption (not relevant at the time, but quite relevant now). It achieved 15 miles/ gallon. Oil companies have huge financial means (they literally have the same revenues as the governments of countries like the Netherlands)... and it can be expected that they protect their interests. However, for the sake of the discussion, I would propose that we don't accept the financial power of the oil companies as the only excuse for the disappearance of steam engines from small scale applications in the automotive and train industry. By now, I would indeed advise to find another application for steam engines. The car companies are very conservative. The least conservative ones look into new engine types: electric. I very much doubt that steam will be applied in the near future... although it's a possibility. You must be aware of the way heat exchangers are tested. It's relativelt straight forward to test the heat transfer coefficient of a heat exchanger. I very much doubt that the entire world of heat exchanging simply got it wrong. The new designs you mention probably don't appeal to you because they have used different design criteria. You may be on to something. Did you publish the results somewhere other than the patent? Did you seek cooperation? You're in a tough market where many manufacturers are trying to kill each other. Most existing applications for an engine are already established markets (meaning it's tough to get in - you'll meet opposition with bigger financial means than you). But if you can find an upcoming market, then you may be able to squeeze steam power in. Not entirely true... Steam power isn't used anymore... but steam itself it used a lot - for heating in chemical factories. Almost the entire chemical industry has steam systems - and those are powered by boilers. Those can be in the hundreds of megawatts, depending on the heat requirements of the factory. Fuel for these boilers is generally speaking a waste product from the factory itself, or often natural gas. I have little to add... you convinced me that steam power can actually be applied in cars. Technically, that is. But it's not... and there are huge financial interests to keep it out. And in the future, steam power may be overtaken by electric cars. Still, a start-up time of 40 seconds is a drawback. Even if this can be reduced to 20... people will grumble. Remember that most cars are only used to drive around the block. I wonder what the fuel efficiency of modern steam powered cars would be. The fuel efficiency mentioned earlier (15 miles / gallon) is rubbish... it's about the same as a Hummer. The whole point of the steam engine discussion here is that it should be so much more efficient... of course, the only data I have here is from 1924. Finally, the need to fill up cars with water and fuel may also be considered inconvenient (it's not really a problem - but it's tough in marketing terms).

You ask a good question. I think that steam cycles can definitely be more efficient than internal combustion engines. However: They are slow to start up. Cars however are not always built only for efficiency... they are built for practicality. And then there is the *bling, bling*-factor which is so hard to quantify. Anyway, I think that almost all car manufacturers think that it's hard to pick up girls with a steam powered car. A very practical reason why trains often run on electricity in many countries is that it can be transported through a cable to where it's needed. Electric trains don't refuel at all. A recent improvement is the combined cycle power plant. This is a combination of a gas turbine (like used in aircraft), and a steam cycle. To do something similar on coal, you need to gasify it first... which is difficult to do cleanly in small scale applications. It's being developed for large scale though. It is called "integrated gasification combined cycle" (IGCC). All these things are being researched right now. Large companies like "Siemens" do research on the world's largest turbines to get out those few extra percents of power. They indeed approach the theoretical maximum, but they push the overall efficiency by allowing for higher and higher temperatures. those solar things don't exist because they're simply too expensive to build in most places on earth. They exist in Spain though. I believe you have a point that the heat exchangers required for small scale steam power are not up the the task. Large boilers are the way they are because combustion gas (including soot, and a lot of other stuff) passes through it... so it must be easy to clean. A modern boiler is indeed a very large piece of equipment, and seems very bulky (although it's very efficicient, it has few losses...). The field of heat transfer is a well established field of research, and I wonder how you want to make a giant leap forward. Trying new geometries is not a new concept... I am aware of your patent which shows a heat exchanger with a significanty increased heat exchanging surface area. But that larger surface area makes it difficult to clean, and therefore it's inconvenient for dirty gases. The increased heat exchange surface would perhaps be able to reduce the start-up time of a steam cycle, if you simply allow more power (more heat) to be transferred to the water by using more fuel... But you can also simply reduce the water reservoir. Frankly, I don't see how you can make any large improvements at all...

... so it's easier to fall on your back when you accelerate?

Nickname? You're suggesting you guys don't use your real names? Damnit... On a more or less serious note: I didn't so much choose my nickname... it sort of happened when I logged in the first time.

Extracting the water at the top will use more energy than you can get from the turbines... It has to use more energy, because if it didn't you would have invented the perpetual motion machine - which is impossible. If your next thought now is: come on, how hard can it be to squeeze some water out of a tree? Remember that you also don't get a lot of energy from a few m3 of water at just 10 meters high. It doesn't take much to waste all that energy.

The Troll platform was the tallest structure ever moved by man (according to wikipedia) at 472 meters. A mile is too much. I assume that you are referring to the Deepwater Horizon oil spill in the Gulf of Mexico? As Ophiolite said, it was floating. However, I believe (and wikipedia agrees with me) that the platform was dynamically positioned... meaning that it was held in place by constant measurements and adjustments, not by lines. I think that mooring lines of several miles long can be unreliable, and may also stretch too much to be of use. The last remark is pure speculation though.

What would be the point of a stationary base on the ocean floor? Unless you are the bad guy in a James Bond movie and you just need a secret base for your evil plans, you can't do much on the ocean floor. You'd be stuck in a spherical, or perhaps cylindrical home. You can only go out in a very heavy spherical submarine. Just forget about walking around yourself. But if you're only going to be able to move around in a bathyscaphe, why not make the trip a few kilometers longer, and actually go back to the surface? It does not require much energy. On the moon however, it does take a significant effort to come home. The benefit therefore would be that you can keep a crew on the moon for a while for research purposes. We've already learned that special suits will allow people to walk (or hop) around. What would be easier? The ocean floor. But it would also be more pointless.

I think that it can be done. Steering can be a bit of a trick... but eventually it should work. The reason that it's not widely used is probably that normal boats are simpler and better for the same job.

I voted for the supernova... But I'd like to place an additional comment: the background color and font are WAY more important than the logo. So, I hope that we can still have the very calm color settings that we have now.