Half a croissant, on a plate, with a sign in front of it saying '50c'
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Outside the bag the box came in.

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Self-raising house

Energy storage
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Renewable energy has the problem that it's intermittent.

So, capture energy and store it.

Batteries are one solution, but they're expensive.

Why not a hydraulic accumulator ? A simple, safe, well-known technology, achieved by using hydraulic rams to lift a heavy weight against gravity. The energy can be retrieved quickly, at a variable rate, by using a turbine.

A windmill can drive a hydraulic pump directly. Solar panels can drive an electric pump. All that's needed is a very heavy object.

Well, the house is there already. Pour a concrete raft and fix hydraulic rams, supporting a base of girders. Use some of the dead space for a water tank. The ram diameters are small, so they work at very high pressure; thus the volume of water required is also small.

The pistons of the rams are fixed to the raft base. The ram cylinders stick up inside the house, concealed within walls - this means that the lift height is from near zero to arbitrarily high, if you're happy with ram casings poking out through the roof.

When renewable energy is in surplus, the rams slowly lift the entire building. When energy is required, it descends. Importantly, the energy is available as direct mechanical rotation, or it can be converted into electricity via an alternator.

In tornado areas, just vent the system and the building can literally duck and cover until it's safe to come out again.

8th of 7, Jul 20 2017

Electric Mountain http://www.electricmountain.co.uk/
[hippo, Jul 24 2017]

The Mekarsky system http://www.douglas-...rair/comprair.htm#m
french. [8th of 7, Jul 24 2017]

How does a propane refrigerator work? http://homeguides.s...dge-work-84254.html
[Ling, Jul 25 2017]

[link]






       //ram casings poking out through the roof.// sp. "bell towers".   

       Do you think this could be retrofitted? Admittedly we've only got bell towers on three of the four corners, but the fourth could be built easily enough. I'm imagining the energy storage available from 27,435 cubic metres of granite and two-thirds of an acre of leadwork. Would the system cope with significant fluctuations in the mass if, for example, Sturton visits for the weekend?
MaxwellBuchanan, Jul 20 2017
  

       Since that neutron-bombarded potato experiment disaster, hasn't he had to register his travels with the Geologic Service?   

       This suggests an alternative: just lift Sturton.
RayfordSteele, Jul 21 2017
  

       This begs for an intricate Halfbakery variable staircase where the tread/rise ratio stays constant. Queue the special musical accordion steps.
wjt, Jul 22 2017
  

       D'oh, Didn't I mean constant tread and rise size for varying height.
wjt, Jul 22 2017
  

       Do you want Baba Yagas' house?
...because this is how you get Baba Yagas' house.
  

       No, it isn't. The KFC is next door ...   

       // This begs for an intricate Halfbakery variable staircase //   

       Feel free to design one ... but the simplest solution is a walkway resembling a ship's gangway. One end is fixed to the house; the other is on rollers, on an embankment with a concrete pad, at half of the maximum height of the building. As the house rises and falls, so the rollers allow the walkway to smoothly change its angle to adapt. This also improves access for wheelchair users and Daleks.   

         

       // Queue //   

       Sp. "Cue"
8th of 7, Jul 22 2017
  

       Note that self-razing houses are baked by the London apartment authority.
RayfordSteele, Jul 22 2017
  

       //The KFC is next door...//   

       Did a tile repair job in a KFC once, haven't really been back there since but I do appreciate the advice.   

       //Sp. "Cue"// What, pushed with a long pointy stick? Queue works also, especially if there are many designs.
wjt, Jul 23 2017
  

       A 100t house raised 10m will give 2.7KW for an hour. It's surprising how much weight needs to be raised to store the kind of energy that households need.
Ling, Jul 23 2017
  

       If the system were pneumatic rather than hydraulic, it would store considerably more energy due to compression of the gas, no?
MaxwellBuchanan, Jul 23 2017
  

       No, because of heating losses during compression. With a gas, the process isn't adiabatic; but liquids are almost incompressible.   

         

       // It's surprising how much weight needs to be raised //   

       <Chief Brodie>   

       "You're going to need a bigger house ..."   

       </Chief Brodie>
8th of 7, Jul 23 2017
  

       //No, because of heating losses during compression.//   

       Wrong, I think. After all, compressed gas is a viable means of storing energy, so clearly the thermal losses on compression/expansion are not equal to all the energy stored by the compressed gas.   

       So, you end up with at least some useful storage in the form of compression (even if some of that energy is wasted as heat), _plus_ the same amount of energy stored as houselift that you would have stored with hydraulics.   

       Also, of the pistons are insulated, you will not lose all of the thermal energy arising from compression - some of it will be retained as heat, and will be recoverable when the gas is vented through the turbines.   

       So, a pneumatic system will store more energy (for a given degree of liftage) than a hydraulic one, at the cost of slightly greater losses.   

       Given that the issue appears to be the amount of energy that can be stored by lifting a typical peasant house weighing only 100 tones, I think pneumatics are the way to go.   

       Of course, a rupture in a pneumatic system will be more explosive than in a hydraulic one, but that's just an added bonus.
MaxwellBuchanan, Jul 23 2017
  

       What you're doing there is asking a reciprocating-piston compressor to operate at very high temperatures.   

       Consider the General Gas Law (PV=RT). Work is done compressing the gas, thus as the volume is reduced and the pressure rises, the temperature also rises in proportion.   

       If the cylinder and delivery pipework are insulated to deliver the heated air, retaining its energy, to the rams, then the cylinder and piston will get progressively hotter. Eventually, they will get so hot that Bad Things will happen, even with superb lubrication.   

       While the combustion temperature of an IC engine is high, the cylinder walls are cooled, as is - in some cases - the lubricant. That means that the actual liner temperature stays low. Heat is continually removed, usually by a circulating fluid.   

       Compressor cylinder housings are typically finned, with fan-assisted air cooling on larger units. This is not just for show - hot air isn't a probem per se - but to ensure that the compressor doesn't get hot enough to destroy the temper on the piston rings, and melt the outlet valve.   

       When the pressurized gas is released through the turbine, it in fact becomes extremely cold - so much so that icing can be a problem.
8th of 7, Jul 23 2017
  

       Well, I wasn't planning on operating this system at 2500rpm. Moreovermore, the compression will be quite slow, likewise the decompression, allowing both heat and coldth to be transferred away from critical points and distributed more uniformly.   

       If needs be, the heat arising during compression could be bled off into the domestic hot water system, and the coldth arising from decompression could be siphoned off into a freezer or air conditioner.   

       And in any event, the total energy density of the system at full capacity will be higher.   

       As a bonus, the system could be driven over and above the pressure needed to elevate the house, with the travel of the pistons limited by some sort of stop pin. In an emergency, the stop pin can be pulled, launching the house and its contents safely out of the way of an approaching meteorite, elephant or Jefuckinghova's Witness.
MaxwellBuchanan, Jul 23 2017
  

       // stop pin //   

       Ram end cap, held on with explosive bolts, MUHWHHAHAHA !   

       Ahem.
8th of 7, Jul 23 2017
  

       Oh, very well. But only if I can have one of those big red buttons under a liftable cover, and a lever marked "ARM".
MaxwellBuchanan, Jul 23 2017
  

       You have to break a glass panel to get a key. A yellow beacon starts to rotate, and a warbling alarm starts to sound. Then you put the key in a lock and turn it.   

       Enter the eight-digit code on the keypad and open the access door. Pull out the pin, and grasp the yellow-and-black striped handle. Press and hold the catch, push the handle in until you hear a click, then pull the handle sharply out and down.   

       The amber beacon is replaced by a red one, and the warble becomes a klaxon. You can now ift the cover over the main controls until it latches. Set the desired time delay on the thumbwheels.   

       Flip the red cover up on the "ARM" toggle switch. The emergency red lighting will come on. Then lift the protective covers on the two red firing buttons labelled "FIRE" and place a thumb on each one. When the annunciator display shows "ARMED", press both buttons simultaneously and hold down for a count of three.   

       "ARMED" will disappear, and the countdown will commence and be displayed.   

       What you do next is entirely up to you.   

       To abort the countdown, follow the abort procedure*. Be aware that when the coundown goes below 5 seconds, it can not be stopped.   

         

       *Which is completely different from the arming procedure.
8th of 7, Jul 23 2017
  

       Get the butter and marmalade, and get ready to transfer the toast to your plate before it cools?
pocmloc, Jul 23 2017
  

       Ah, OK. You mean like the system we've got on the East Absinthe Cellar door? Only I'm a bit worried that Sturton might get confused and accidentally launch the house at an inconvenient time.
MaxwellBuchanan, Jul 23 2017
  

       Back to the energy storage, imagine the 100t MB gatehouse (outhouse?) is suspended on a 10m long pnuematic cylinder of area 1m2. Initially the pressure is atmospheric, but the house drops until the pressure in the cylinder is enough to support the gatehouse. You can see that the drop in height gives the energy input. It works out around 9m drop and Isothermal compression will store more energy as long as the heat is somehow returned on expansion. But if the gatehouse finally rested at 10m height, this would give initial conditions of 100m for the same compression. So, the energy storage could be boosted 9 or 10 times.   

       It might prove to be even more effective to get some really good double glazing, and pressurise the gatehouse itself. Although some caution ought to be advised for pressurising outhouses, as all sorts of shit might happen.
Ling, Jul 23 2017
  

       // Isothermal compression will store more energy as long as the heat is somehow returned on expansion //   

       That's the killer - how to keep the heat in the gas until the energy is wanted. Even if the cylinders are heavily insulated - maybe even being a Dewar construction - the material they're made of is going to have a much higher specific heat than the gas, so energy will pass from the hot gas to the cooler cylinder. The cylinder and piston would have to be machined from a strong material with a very low thermal conductivity, like SilON.
8th of 7, Jul 24 2017
  

       I kind of reasoned like this:   

       If the house compresses the air Isothermally, then it would drop further than if it compressed the air adiabatically. This is due to the adiabatic compression having hotter gas and therefore building pressure more rapidly.   

       Since energy storage must be initially related to how far the house drops, then isothermal compression must receive more energy. However, much is lost as heat. The reverse action must gain heat from the environment in order to return as much energy upon decompression.
Ling, Jul 24 2017
  

       The great thing about this kind of energy storage is that it provides power very quickly compared to other kinds of power station - e.g. "Electric Mountain" (see link) can go from 0 to 1,320 MW in 12 seconds. If houses had grid feed-in links and were properly networked, this could be used for meeting national power demand spikes - so you would see an entire neighbourhood of houses gradually sink as they fed in power to meet a sudden demand spike elsewhere.
hippo, Jul 24 2017
  

       The point about pneumatics rather than hydraulics is not just one of efficiency - a pneumatic system will indeed be less efficient than a hydraulic one, since not all heat will be recoverable.   

       The point was about energy capacity, which will be higher for the pneumatic system.   

       Let's take an extreme case as an example. We raise the house pneumatically, and we just throw away all the heat of compression. So now our house is at the top, and we have a pressurized gas cylinder.   

       We now lock the house in place, and vent the pressure through a turbine, generating X amount of electrical energy. We can now engage a rack-and-pinion system so that the house can be lowered whilst driving a generator. In this way, we can recover the gravitational potential energy of the lifted house.   

       Finally, the house is back on the ground. We have recovered (a) some energy from the compressed air plus (b) as much energy as possible from the gravitational potential of the raised house.   

       So, for storage efficiency go for hydraulics. But for storage capacity, go for pneumatics.
MaxwellBuchanan, Jul 24 2017
  

       // must gain heat from the environment in order to return as much energy //   

       In your 19th century, compressed air was used for motive power - trams were one application. There were problems with icing, and limited power; a heater called a "bouillotte" - a tank of hot water to heat the expanding air.   

       They were quiet, safe, and pollution free, but energetically rather poor.   

       <link>
8th of 7, Jul 24 2017
  

       [Max] Alternatively, could the pressurised gas held in the cylinders not be vented (expanding as it does so) to provide absurdly expensive and inefficient air-conditioning for the house?
hippo, Jul 24 2017
  

       It could. It can also provide some cooling even as it goes through the turbines.
MaxwellBuchanan, Jul 24 2017
  

       Under the house locking system, wouldn't there also be a heavy hydraulic head?
wjt, Jul 24 2017
  

       Why? With my rack-and-pinion system we're not using any hydraulics. The house is lifted pneumatically, and descends using a rack-and-pinion that directly drives a generator (through some very high gearing). It's not necessarily the best system, but it does show that you can store more total energy.
MaxwellBuchanan, Jul 24 2017
  

       Racks and pinions would be rather costly. A set of ropes and pulleys would do the trick. This concept was baked in grandfather clocks.
bhumphrys, Jul 25 2017
  

       Brilliant. Should the cats be minced before sealing them in the pyramid chamber, or can they just be roughly chopped, for instance by a tree chipper ?
8th of 7, Jul 25 2017
  

       I'm reasonably sure (enough to wager, say, [8th]'s next paycheck on it, should he ever receive one) that you can't generate static electricity purely by interfeline friction. You need some alternative material, in addition to the cats.   

       Technically and theoretically speaking, the most suitable material to act as an electrical counterpart to cats ought to be stac, but I'm not sure where you could get that from.
MaxwellBuchanan, Jul 25 2017
  

       Given that one of the most energy-consuming home devices is air-conditioning and you most often need air-conditioning when the sun shines, there is surely a market for a device which converts solar energy into air-conditioning without the intermediate step of converting the solar energy into electricity. One approach might be to shade your house with a material which absorbs solar energy but cleverly converts it into another form, like chemical energy, rather than re-radiating it. If this material had moisture-containing capillaries, the solar energy could also be used to evaporate water from these capillaries so that there would be an evaporative cooling effect as well.
hippo, Jul 25 2017
  

       // you most often need air-conditioning when the sun shines //   

       ... except at night ?   

       Use a parabolic mirror to heat a steam tube. Convert the steam pressure directly to mechanical rotation, and drive a refrigerant compressor. Use a bit of the rotation to drive the feed pump that returns condensate to the steam tube.   

       There are a couple of potential problems:   

       A shaft seal on the compressor might leak. However, this can be overcome by magnetically coupling the drive through the casing via high-speed low-torque gears.   

       The compressor is probably going to need to run at constant speed, so any variation in steam pressure may cause problems. Using a hydraulic or pneumatic reservoir as a buffer may be an answer.   

       Actually, Solar->steam->pump ->hydraulic accumulation may be more efficient than Solar->photovoltaic->motor ->pump->hydraulic accumulation. PV cells aren't particularly efficient. Solar-thermal can harvest a broad E-M spectrum including IR.   

       // The units would require keeping dry. //   

       OK, bake until dry after the mincing process. Got that, thanx.
8th of 7, Jul 25 2017
  

       //solar energy could also be used to evaporate water from these capillaries//   

       In places where water is not limiting, it should be possible to design roofs to accommodate a moistening trickle from a plumbed-in device in the ridge. If 5l/hr were thusly evaporated, you'd have something like 10kW of cooling.   

       I would also like to point out that "moistening trickle" is very euphonious phrase.
MaxwellBuchanan, Jul 25 2017
  

       The solar-energy-absorbing and air-conditioning roof I suggested could also absorb CO2 and supply you with fruit, if properly designed.

//Actually, Solar->steam->pump ->hydraulic accumulation may be more efficient than Solar->photovoltaic->motor ->pump->hydraulic accumulation// - yes, that was what I was thinking - the conversion process is very inefficient.
hippo, Jul 25 2017
  

       //could also absorb CO2 and supply you with fruit// fantasy, sheer fantasy.
MaxwellBuchanan, Jul 25 2017
  

       All right, it's sheer fantasy. Just as long as there's enough spare energy to drive the cat-mincer; the steam condenser coils can be used for the drying.
8th of 7, Jul 25 2017
  

       Refrigeration using a small heat source is economical and efficient. Propane refrigerators are available, and the flame could be substituted with focused sunlight.
Ling, Jul 25 2017
  

       Absorption refrigerators are a well understood technology; and very quiet. They use ammonia and water - both are cheap, and easily available. Even better, there are no moving parts.   

       The Einstein-Szilard design is similar, but operates at constant pressure. However, it is apparently very noisy in operation.
8th of 7, Jul 25 2017
  

       //it's sheer fantasy// My first mental recall, stimulated by this idea, was of Marineville.
wjt, Jul 26 2017
  
      
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