# Heating skyscrapers utilizing their own mass?

Whoa! don’t know what happened in the closed thread…

Here’s what I intended to ask:

I’m posting my theory in GQ on the assumption that there is something wrong with it, and someone can explain the flaw…

So if pressure = heat (or at least generates heat), could you heat a skyscraper (or let’s say, capture a sufficient amount of the heat and pump it into the environmental control system to make the system economically feasible) from the pressure it’s own mass generates at the base of the structure?

This is another one of those, “Sounds too easy, there’s gotta be something wrong here”. But nothing leaps out at me as being wrong, except perhaps the energy conversion wouldn’t be effecient enough.

OTOH, it sounds suspiciously like a perpetual motion machine, which cannot be.

When something is compressed it will heat up, but once the compression becomes static (i.e., not increasing) no additional heat is generated.

The heat created is from the increase in pressure not the pressure itself. The building exerts pressure on the ground, the ground heats a little during construction then cools back to ambiant.

the pressure gets exerted, right? and you extract some energy.

now the building-ground system is in some kind of equilibrium. the only way to get more energy from pressure would be to relieve the pressure on the squeezee (that is, life the building or something).

and to do that, you’d need to expend energy.

jb

err, lift the building.
all that said, though, i can imagine a system where pressure is used to heat water (ever so slightly).

imagine a building on stilts. now replace the stilts with springs. enclose the spring apparatus. the pressure of the building compresses the springs and heats them.

the system now floods the springs with water. this cools the springs (causing them to expand somewhat) and heats the water. a thermometer in the water vents the water when the water reaches a certain temp.

springs compress again, springs get flooded, etc.

jb

Except that cooling the springs would cause them to contract, not expand.

nope, doesnt work. the energy you need to re-raise the building for the next load is exactly the same as the energy you get from compressing the springs.

…If you have a perfect system, which, of course, you don’t.

aarghhh!

you’re right.

damn…

Well, I knew there was a hole somewhere.

I suppose if you make it massive and bouyant, wou could route the city’s water supply under it to lift it, but that seems rather extreme for your average skyscraper.

To hijack my own thread, whatever happened to the idea of putting enormous hinged barges off the coasts? The idea being that wave action would flex the hinges, which would in turn generate electricity. Is this description clear enough? Imagine the letter V, with a hinge at the line intersection, and wave action flexes it between a flat line and the V shape?