Engineering

I am trying to size a heat exchanger for a solar water heater. It seems that most people online tend to either buy a prebuilt exchanger with some arbitrary "good for 3 people" rating or just wing it. I googled to death but either google is to dumb or I am too dumb to find the answer. Id like to take what I know which is: temperature of incoming water temperature of water in holding tank volume / second of incoming water heat volume of water (4.18 kj/kg) where 1kg=1liter so if I have 40*F incoming water (using *F for degree symbol) and have 160*F water in the holding tank, how many square feet of surface area do I need to get the 40*F water up near 160*F? …

I'm looking for books/texts on automotive monocoque chassis design. Can anyone help?

if we took an electric car and put energy turbines in the wheels would it be possible to power the car without having to charge it up every 5 minutes

How to build solar panel...

HEY Y'ALL, Why is a pencil made with 6 sides? I know that they make round pencils so the hexagon shape can't be for grip. Any suggestions?

Can anybody comment on electric tractors . If you use an electric tractor to plant corn for instance and generate the power by solar and wind can that qualify for carbon credits. If you compare biodiesel with electricity generated by wind and solar you will use a much smaler portion of land to generate your energy needs.

i need more info on about the above title so please help me with info please provide info about the feasibility

In discussions about hydrogen fuel cell vehicles, it's frequently said that "the infrastructure" would have to be in place before they could be practical, and the infrastructure itself wouldn't be profitable unless vehicles were widespread. Ok, so my question is: what infrastructure? I guess it boils down to me not really seeing why you couldn't treat a hydrogen fuel cell as a rechargeable battery. Instead of having water vapor as exhaust, why not keep the water in the system? Then plug in the car to supply electricity for separating it into hydrogen and oxygen. Keep the hydrogen, let the oxygen go. Sure, the car would get heavier as you go, but not by that much, and …

Hello, im struggling with what should be a simple problem but I just cant get my head around it. Basicly, if 8kg is needed to move an object horizontally at 0.25m/s what is the force?. (It's not just f=ma is it?). Thank you

Hello, We have a science project where we have to produce a maximum output of electricity using hydroelectricty. We have little 12V motor and all the necessary gears and all... The rest is for us to decide.... So, what should I do? I don't know anything about hydroelectricity/turbines and all...We thought (my team and I) about doing a Pelton wheel (http://en.wikipedia.org/wiki/Pelton_wheel) that we will eventually attach to the motor and produce that way some electricity with water but my question is: How can I maximize the energy? Is there some things that I should know about turbines and stuff that can help us optimize the produced output? Thanks in advance.…

i know theres ideas for powering spaceships off of fusion, engine uses fusion to run, and use fusion to power spaceship electrically too, so long as they find a solution to these fusion problems, {which i think doing this in space would be way easier in space than on earth with gravity}, but how, if im right, the process of fusion connects atoms together. i dont see how you can use that to power anything, or use that as an engine an space. fission, i understand, could be used to propell spaceships, but you need radioactive materials, and is more dangerous, id rather use fusion because the fuel is abundant and its not any where near as radioactive.

I'looking for some literature about tube finned with wire loop spirals, but I have just found commercial references claiming that this tube is highly superior in performance than strip finned tubes. I would appreciate any indication.

how could solar panels power a car and how would you get the most energy out of it (im talking about school project model cars)

My TV's antenna is rust, does it affect the detection of signal ? Short question, help me with it? thanks so much

You may have heard that there are many stories on the internet about adding some magnets somewhere in your engine to make it run more efficient. On most scientific forums and websites, these stories were put in the category of hoaxes, nonsense and such. I recently found an article which seems to come from a more reputable source: Philedelphia's Temple university. They too claim that an electric field will significantly increase the fuel efficiency of the car (a diesel Mercedes), because the viscosity of the fuel is reduced in the electric field. This in turn makes the fuel injection more efficient. I'm not convinced, mostly because I don't understand how it's sup…

Coal liquefaction is the conversion of coal to produce synthetic fuels. To convert coal to synthetic fuels, a process has been developed that requires the coal to be in contact with a hydrogen environment at high temperatures and pressures. The major objective of coal liquefaction is to produce synthetic oil to supplement the natural sources of petroleum. Liquid and solid products from coal can be used for fueling transportation vehicles, providing fuels for power generation, and yielding raw materials for chemicals. Coal-liquefaction plants will be expensive, but their products should be very competitive when world oil production declines.

Hi. I’m doing a science project in high school, in which I dismantled a microwave, and took the microwave magnetron, capacitor (no need to worry; the capacitor was discharged) and transformer out. Before I go on, the premise of the project was to get a magnetron to emit a microwave, which would be received by a rectenna (composed of an isolated microwave antenna—in this case a wi-fi antenna, connected by wire to a Schottky diode) which rectifies the AC current and turns it into DC current. In other words, wireless power transmission. Now, I’m particularly having trouble with the transformer. I’m planning to hook up the apparatus to a variable power supply, in whic…

Even I think it would be far safer (both for the general public, and for security purposes) just to automate transport and enclose it. Like said above, if enclosed there is nothing stopping an enclosed system running seamlessly at high speeds. There isn't actually a need for a general flying system of vehicles.The problem that needs to be solved is of safety, and congestion. Both of which automated systems can solve. But then again there isn't need of nuclear warheads either...

I'm analysing a heat transfer problem, but I am a bit rusty as it's been a while since I've taken the course. I have two concentric tubes (annulus), and the outside tube has water flowing through it, to cool the solid rod in the middle. I am interested in the temperature gradiants of both the rod and the water. I have the power of the rod (q), the flow rate (Q), the initial temperature of the water, and the area of both the rods. Can this be solved from this? It seems as though it would be an easy problem, but I have not found the correct equation yet.

I was clicking through Youtube on a cold evening during the holidays. I just want to share it with you all. I always knew the world was crazy during the cold war... but a nuclear powered ramjet cruise missile the size of a locomotive? It's a good documentary, considering it's from the Discovery Channel, or Discovery Wings - lots of info, and pictures of how it is actually built and how it works. It's in 5 parts (total of about 43 minutes): Part 1, Part 2, Part 3, Part 4, Part 5. There's also a short wikipedia page about it. And just to have something to discuss - does anyone think that a nuclear missile that cannot leave the atmosphere makes sense? I think i…

Just as birds serve as a good inspiration for the design of heavier than aircraft, fish are a good inspiration for neutral buoyancy aircraft. Here's a video of a model airship that uses a tail, pectoral fins and dorsal fin for thrust, direction and stability control.

is there a way of incorporating a turbine onto a scramjet in order for it to be completely self propelled? that way it wouldn't need to be launched from another vessel.

I read this 5 years ago now. http://auto.howstuffworks.com/flying-car.htm They say within the next decade, and this is something I've always been looking forward to. Realistically though, what about it's fuel requirements? Not only do you have to power it's systems so it can move in the normal two dimensions a land car would have to, but you also have to contend with gravity and keep it above the ground. We don't even have self driving cars now (at least they aren't readily available at local dealer as far as I know) They have the parachute as a failsafe, surprised they don't have anything else, like a system which will automatically land the car before you r…

I'd like some advice regarding buying or building an air dehumidifier. I know they exist, but I have no experience with them whatsoever. I've got a small ( ~ 20 m2) cabin-like house with serious moisture problems. Food, papers and clothing will be ruined if left there. The surface is near ground-water level, and because of the surrounding trees it's in the shadow for most of the day. The average room temperature is pretty low. The trouble is that I haven't got electricity installed to run a dehumidifier. I'm willing to invest in a 20-30 watt solar panel or fan, but I know it can be done without electricity too. I'd prefer a solution that can run 24/7 also when I'm n…

Have a question. I noticed that all the outlets in one room have no ground. None in the boxes. This was a system that was used way back. I installed a gfci and used a test light which showed an open ground. When i connect a jumper between the ground screw on the gfci and the line neutral the tester reads normal. I have my own thoughts on the safety of this but would like to here some others. Thanks all