heating bathroom using NO power!

Discussion in 'Designing, building, making and powering your life' started by living simple, Mar 30, 2008.

  1. living simple

    living simple Junior Member

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    Hi all,

    I was wondering if anyone has had any success in heating their bathroom (or any other freezing room in the house!) without using power? We live on solar power in Tassie and don't want to drain it anymore, so would love any suggestions re heating. We are thinking about running water thru pipes from our woodheater into the bathroom or hot air from the back of the woodheater into the bathroom (but again, not using a fan/power) - has anyone done this before?? Or know of an appropriate website which would help me out, etc?

    Thanks in advance,

    Cheers
    Lyn
     
  2. dgriffith

    dgriffith Junior Member

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    Re: heating bathroom using NO power!

    What's the distance between wood heater and bathroom? Hard to convey heat over a fair distance without a small pump/fan.

    You can make a thermosyphon water loop on the back of the wood heater - this works on the principle that hot water rises and cooler water sinks, thus no pump needed. I've used this with small stationary engines to cool them without the need for a pump - that's dumping about 3kW of heat whenever the engine is running.

    The pipework must:

    - be on a constant rise from the back of the wood heater to the bathroom.
    - tee off there, with a vertical pipe at the highest point for filling the system (and venting if it gets to boiling! So make sure it vents somewhere safe. )
    - drop down through whatever you have there in the room to radiate the heat.
    - then return pretty much direct to the bottom of the wood heater preferably on a downwards slope to the heater.

    It doesn't have to be much of a rise to the bathroom. But importantly,no downward kinks on the upwards pipe (hot water will rise to that point and "jam", refusing to go downhill), also avoid going below the level of the wood heater on the return pipe (cold water will tend to pool at that point and refuse to rise up)

    You want to insulate the hot pipe as much as possible and expose the radiator pipework in the bathroom as much as possible - the cooler you can get the water at this point compared to when it exits the heater, the more heat transfer will take place. Although I haven't tried it, you could have the pipe enter (and fill with water) a simple shallow box made out of tinplate - a 2ft x 4ft x 1/2" tinplate box set off the wall by 1/2" will radiate a lot of heat. It also provides a fair weight of cooling+dropping water to drag the rest of the system along. Whatever you use, the water must be in a constant downwards direction in this section - no upwards flow. Same sort of thing for the heater coils at the other end - always sloping upwards.

    Hope this makes some sense! :D
     
  3. living simple

    living simple Junior Member

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    Re: heating bathroom using NO power!

    Hey, thanks SO much for taking the time to explain all that! My husband has printed that out and gone off studying!!

    Our bathroom is approx 5 metres in a straight line against a wall - so i think that should be fine. We'll be looking into it!

    Really appreciate what you have done . . .

    Cheers
    Lyn
     
  4. Mike_E_from_NZ

    Mike_E_from_NZ Junior Member

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    Re: heating bathroom using NO power!

    Whilst dgriffith offers some sound advice on transferring heat, and he did give a good answer to your question, can I suggest another way of looking at this?

    Given that you are willing to invest (possily substantially in time and materials) in heating the bathroom, are you willing to invest in possibly not needing to heat it?

    What are the reasons you wish to heat it? Is it because the bathroom is so cold before you use it? Or does the moisture from the shower make it uncomfortable to be in when the day is cold?

    Human comfort is more about radient heat than it is about air temperature. If the surfaces of a room are cold, then your body will radiate heat to them and you will feel cold (whatever the air temperature). And vice versa (think of a crisp, but sunny, winter's day).

    Thus, insulation is important - and easy in such a small room.

    Even if you decide that heating is necessary, remember that a cold wall will mean that the side of your body facing that wall will still feel less comfortable than that on the radiator side.

    Probably more important than the 'before-shower-comfort-level' is the 'after-shower-comfort-level'. That is, "what happens to all that water?"

    Here is a website that explains it far better than I could:
    https://www.appropedia.org/Sun_Frost_ene ... ent_shower

    My suggestion is to cover off these things before trying to heat. Heating takes time and effort, over and over. Good design only takes effort the first time.

    Mike
     

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