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Say I hook a 1KW steam engine to the steam heat in my apartment, and generate 1KW of electricity (the engine is 1KW mechanical, not 1KW thermal) from it, so I don't have to pay ConEd.

That means I am getting 1KW less heating power for the same amount of steam. Does it take the landlord's heating plant 1KW more to keep my room at the same temperature?

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Thanks David, for the other tags. I think the answer depends: was I providing 1KW of heat via electricity before putting in the generator? Probably yes, so the heating plant will have to make up for that with 1KW of additional steam heat. But I am not obligated to provide 1KW of heat. The issue of theft is outside the scope of the forum, I think. –  Bobbi Bennett Dec 14 '12 at 6:15
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2 Answers 2

Before you hook up your generator you're using electricity from the mains. If, as you say, the electricity is used only in your room then it ends up as heat and heats your room. For example the electricity used by your PC is expelled by the cooling fan as hot air and heats your room that way.

Because your room has been heated by the electricity you use, the temperature difference between the steam radiator and your room is lower, which means heating your room requires less heat from the steam and therefore your landlord needs to spend less on fuel.

If you don't use any electricity from the mains all the heat has to come from the steam. Some of the heat comes directly from cooling the steam, and some comes from generating electricity and (eventually) turning that into heat, but in the end it all comes from the steam. That means the landlord needs to burn more fuel to keep the steam at the right temperature, so you are taking the energy from the landlord.

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Exactly what I believe is correct. Even to the subtle word 'taking'. After all, though I am expected to use electric power, I am not required to. –  Bobbi Bennett Dec 14 '12 at 18:40
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The answer is yes, you are stealing energy. You are removing steam from the circuit of heating by your engine.

The heating plant is supplying this energy to you and it will replace it by heating more cool water to bring the steam pressure to the necessary level to keep all radiators at the desired temperature, including your radiators.The parameters of the steam are designed with a specific temperature and pressure to cover the geometry of the radiators and the building.

Maybe it will be easier to understand the "stealing" if you think of doing something similar to hot water radiators, i.e. take your hot bath from the hot water in the radiator. (it has been done).

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I thought so at first, but .. I am putting the heat back! None of the electricity leaves the room, it just runs light bulbs, refrigerator, computers, and they all emit just as much heat (well, ok, a little goes out the window as light) into the room as the steam power turned to electricity would have. –  Bobbi Bennett Dec 14 '12 at 5:39
    
The point is that there is no thermostat in your room that controls the steam heating parameters. It is all designed as one block given the number of radiators (planned according to the size of the room) and the size of the building. The steam that will come out in your room will condense after going through your generator, and you can fill buckets with (it until they cover the floor :) ). If no heat leaves ( than the normal losses) your room will be overheated because the radiator will have the temperature of its design. –  anna v Dec 14 '12 at 5:44
    
If there were a thermostat in your room to control the heater and you kept it constant at 20C while your engine ran, the rest of the building would be underheated. –  anna v Dec 14 '12 at 5:46
    
Well, steam heat is pretty mysterious to me, it is a mystery to me how a landlord regulates heat, and pretty sure to them as well. Hooking up some kind of malarky to their steam I am sure is frowned on, might disturb some balance of pressure and venting air. The generator would, or course, not be allowed to vent steam, it would have to return the condensate. –  Bobbi Bennett Dec 14 '12 at 5:53
    
Look at the image in the link above. There is no mystery. The engineers when designing the radiator system design it for the building and there should be either a thermostat or a table of how to operate the plan according to outside temperatures for the system to give the designed heat. –  anna v Dec 14 '12 at 6:49
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