### Space Related Instructable - Atmosphere/Pressure Sensors

I am really into rocketry, aerospace engineering and space in general. I have met a few people at my college that are somewhat interested in the same but dont know alot about it. So i thought i could build a few different environment sensors like the astronauts use to simulate/demonstrate a few basics. For example i wanted to build a few different sensors. But i cant find any instructables to teach me how to make these....Can anyone help or can anyone direct me to a few instructables that could be used to tweak to work for this purpose? - To help show how the astronauts have to regulate their atmosphere in the ISS or even explain how we don't breathe just oxygen - we breathe a combination of O2 and Nitrogen since Earth's atmosphere is mostly nitrogen. O2 (oxygen) Sensor CO2 (Carbon Dioxide) Sensor N (nitrogen) sensor Display to show all sensor data - To help show how they manage pressure in the ISS and have it regulated by an airlock. Atmospheric Pressure Sensor and Display

Topic by acadena2 3 years ago  |  last reply 1 year ago

### how much does air weigh? Answered

How much does 1 cubic foot of air at 1 atmosphere of pressure weigh? (and for the lmgtfy.com answerers, a google search returned conflicting answers)

Question by revelae 9 years ago  |  last reply 7 years ago

### Pressure, vacuums, and the on earth equivalent?

One atm is equivalent to about 14.7 psi.  Does that mean that if one was in a perfect vacuum a vessel sporting 1 atm would need only hold the pressure of 14.7 psi?  It seems to me that in space (not a perfect vacuum) a craft would only need to hold maybe 12 psi (of course when messing with human life I would definitely allow for 150 to 200% tolerance, but in the end 24 psi still isn't very much is it.  Is there more to it than this, or are all those quotes about how hard it is to deal with a vacuum and how things must be super strong a little over blown.  Going just 11 meters under water exposes you to a little over double air pressure at sea level.  Someone in just a diving suit has been to over 60 times atmosphere and the deepest submarine dive I could find was 1083 atm at around 11000 m.  It just seems to make holding out a vacuum a little overrated.

Question by seedorfj 4 years ago  |  last reply 4 years ago

### Can the change in atmospheric pressure inside the house automatically drive a mounted exhaust fan ?

I used to live in this house some 3 years ago, it had exhaust fans in every washroom , now if i opened up the doors of all the washrooms closed the windows and disconnected the exhausts from electricity and would just move any door in the house slightly it would cause the exhaust fans to go wild and spin like jets ! Now i need to know what principal is involved here ? or was it really happening because of what i hypothesized ? Does it happen in your house too ?  Thanks,

Question by cyber02000 5 years ago  |  last reply 5 years ago

### What's the gas expansion ratio for ethanol?

At normal atmospheric pressure. Don't need too precise a figure, nearest 50 will do. Surprisingly difficult information to find...

Topic by SolarFlower_org 9 years ago  |  last reply 9 years ago

### Looking To Pick Your Skilled Brains

Advice on best how to make a piezometer out of readily available hardware store parts without use of any power tools and access to only a very few hand tools. Basically a piezometer is a clear, straight plastic tube that you attach to the outside of (in my case) a plastic 250 Liter rain barrel (about 1.5 feet diameter, 4 feet high) from top to bottom. The top is exposed to the open air, while the bottom feeds into the bottom of the barrel (by going through the side very close to the bottom). It needs to have a diameter of about 1/2 inch, be very solid, straight and secure, and a 'water level mark' must be etchable in it somehow to indicate the normal level of water inside the barrel when the barrel is full (full means a few inches before the absolute rim of the barrel). The barrel is filled with gravel at the bottom, sand on top, and enough room for a 12" waterhead above the sand. I'm using it as a slow sand filter (SSF). The idea is that the pressure of water at the bottom of the barrel fills the tube up to the watermark against the action of the atmospheric pressure forcing the level in the tube down below the watermark. When the level of the water in the tube is about 15 inches below the water mark, it means the water pressure at the bottom of the barrel has decreased to the point where the sand in it needs to be cleaned (no water getting through). Any ideas will be greatly rewarded in the afterlife. Thanks!

Topic by SozzledBoot 12 years ago  |  last reply 12 years ago

### New Vacuum Pump Idea

I have a new idea about a new type of positive displacement vacuum pump.  Its of the piston variety, but instead of a one way valve which doesn't work when the pressure gets low enough, another piston is used to act as a valve switching between the vessel to be evacuated (when the main piston is pulling a vaccum) and the atmosphere (when the piston pushes the air evacuated out). This solves the one way valve problem.  Could this pull a much lower vacuum?  I need a fairly strong vacuum, but I don't want to have to build/buy a turbomolecular pump. Also, i have a metal lathe, that's why i'm going with the piston variety.

Topic by guyfrom7up 9 years ago  |  last reply 9 years ago

### Solar Power Towers Efficiently Using Brayton Cycle

I want to point out a solar to electric generation concept that has yet to be seen anywhere, even though it originated back during the Carter Administration's ERDA programs of the late 70's. I’m talking about solar power towers that convert solar energy into electricity at the hundreds of mega-watt level. While power towers do exist today, and the world currently does have a handful of them as shown in Fig-1, none use the Brayton Cycle nor can they boast an energy conversion efficiency at the mid to upper thirty percent level.  A group of engineers got together at a think tank organization called Sanders Associates in Nashua, N.H., several decades ago, and designed a unique Brayton Cycle, 100 MW solar Power Tower concept for generating electricity. This was accomplished under ERDA (Energy Research Development Administration) who gave us a phase-2 follow-up contract that took our phase-1 design and built a working scale model at the 10 KW level. This model was tested at the Georgia Tech Solar Research Facility and "registered" ~37% electric solar conversion efficiency. The system used ambient air as its working fluid, and was to be located in open-spaced desert regions. Phase-2 was lost to competition using a closed-loop liquid sodium system that boiled water into superheated steam at 900F to run a turbine that generated ~21% overall electric conversion efficiency.  Apparently, at that time ERDA would rather haul water out to the desert than use ambient air to generate electricity? The politics of their decision is beyond reason and clashes with improving the world’s development of green technology energy.  ERDA shut out our better technological performer and safely locked it away for another day! ERDA's official reason for turning us down: "this technology uses excessively high temperatures (2500F versus 900F) that are dangerous to workman maintaining the equipment". But that was back in the 70’s, maybe we’ve learned to deal with high-temp heat by now?   Solar Energy Concept Using Low Pressure Storage Our solar power tower would collect the sun’s energy by locating its ceramic heat exchanger on top of a tall tower as shown in Fig-1. The tower was located in the center of a field of active sun-searching mirrors (heliostats, Figure-2). These mirrors reflected sunlight onto our ceramic honeycomb heat exchanger, producing a concentrated flux intensity level that heated it to around 2500F. At the same time, low pressure fans generating only a few psi pressure would suck the ambient air through the honeycomb, heating it to just under the 2500F and then passing it through energy storage silos which stored the heat down to ~150F. We purposely designed the energy storage charging phase of our hot air system to work at only a few psi above ambient as a safety feature. The sun effectively acts as the combustor of our jet engine or Brayton cycle engine. Once the sun heats the air, it passes through heat exchangers consisting of a labyrinth of underground silos that are temperature segregated. These silos receive our 2300F airflow and cool it down to about 150F, transferring this heat into solid salt containers which turn to liquid once they have absorbed sufficient heat. Figure-3 is a schematic of this underground energy storage facility and shows the airflow being heated by a fully charged set of silos containing liquid salt-bricks. This airflow direction is reversed when we charge the silo’s salt-bricks. The bricks are kept in specially insulated, high pressure silos (located underground for added insulation) that store the heat energy at one atmosphere for later use. These underground silos act as our energy storage batteries, and when needed would discharge their heat energy accordingly into the moving airflow. This energy storage concept permitted the generation of electricity at night and during overcast days. Two sets of storage systems are required for continuous operation. One would be charging at low pressure while the other is discharging at high pressure through the Brayton engine to generate electricity.   Electric Energy Generation at High Pressure Electricity would be created by turning an electric generator at high speed. The generator was turned by running a jet engine connected to it.  The engine’s combustor for heating the air is effectively the sun, hence the name Brayton cycle for generating our solar electricity (Figure-4). The heat from the molten salt containers would increase the energy of the high pressure air coming from the compressor, and would then force it through a typical turbine that turns this energy into high rotational speed to run the generator and make electricity. Our solar jet engine sucks in ambient air using its compressor, as all jet engines do, and blows it through a series of silos at high pressure whose stacked bricks are held at different temperature levels. We start our airflow through a silo held as low as 150F and work our way up to ~2300F as we pass through our last, hottest silo which acts to complete the effective solar combustion process. This air preheating technique dramatically improves our energy turnover capability and allowed us to convert solar energy into electricity at near 37% efficiency. During our electric energy generation phase, the silos of our Brayton system requires operating at many atmospheres of pressure just as in any jet engine combustor using petroleum-based JP-fuel.

Topic by RT-101 6 years ago  |  last reply 6 years ago

### Hydrogen for renewable energy storage- total system efficiency?

This is a question that has been bugging me for some time, especially since the questions about methanol synthesis revived my interest in energy storage. Say I have a wind turbine or solar panel or whatever, that produces 1000 Wh per day.  If I use that electricity to electrolyse water, store the generated hydrogen at roughly atmospheric pressure in an upside-down water butt or a big gas-tight bag in my shed (don't worry, I'm not going to actually do this) and then feed it into a generator converted to run on H2, what percentage of that initial energy input would I get back out?  20%?  5%? 1%? The follow-up questions to this are a) How does that compare against a battery bank? What about a similar DIY-style pumped water storage system? b) What one component of the system should be improved to raise the overall system efficiency? Electrolyser, storage, generator? c) Are there any other DIY-friendly methods for storing intermittently generated electricity that I'm not thinking of? And, I suppose, d) Does doing this and providing 5-10x your overall power requirements in wind turbines work out cheaper than spending thousands on batteries?

Topic by PKM 7 years ago  |  last reply 7 years ago

### A glimpse into nuclear disaster.

A team of engineers has used an endoscope to carry out the first visual inspection of Windscale 1 nuclear reactor for more than 50 years. In October 1957, it was the scene of what was the world's worst nuclear accident when it caught fire and released radioactive material into the atmosphere.Just over 50 years ago, British nuclear scientists, under political pressure from a succession of Prime Ministers, had been pushing the reactor to and beyond operating limits in an attempt to develop the UK's own independent H-bomb and achieve an "alliance of equals" with the US.When the fire occurred, the scientists were faced with a choice: let it burn, and contaminate Europe, or dump water on it, and potentially die in a nuclear explosion. They chose the latter, risking their own lives to save people who didn't even know there was a problem.That sounds heroic, but the official report into the incident blamed the scientists for the accident, rather than let the US find out about the H-bomb programme just in the days before signing a treaty to share their existing knowledge with the UK.Windscale (now known as Sellafield - the name was changed after the accident) is now in the long process of closing down. Along with jobs, buildings that marked the dawn of the nuclear age are being slowly demolished and moved ... somewhere else. They don't know where, yet, but it will probably end up remaining on site in deep holes (down in the porous sandstone that carries the local water-table).The original piles were shut down immediately after the accident, and the site's AGR reactor was closed down 27 years ago, but it is only recently that they figured out what to do with them, and they are now being decommissioned as a "UK's demonstration project (meaning; "we've never done this before, we'll work out the bugs in remote Cumbria before we try it on a reactor near a city").As part of the decommissioning work, they now need to see what is left in the ashes of the world's second reactor disaster before working out what to do next.I don't know about you, but I'm not convinced that a paper boilersuit would be enough protection. Maybe that's why the chap on the right looks like he's crossing himself...

Topic by Kiteman 10 years ago  |  last reply 10 years ago