Solar hot water - Pre-heater

I have a perfectly good hot water service at home so I wont be throwing it away just yet. But I think I've decided on what I'll do instead. My plan is to make a pre-heater to heat the water that goes into my hot water service, so less energy is required to get my water up to temperature.

I already have a working understanding of heat exchange principles, so I'll leverage my new knowledge and attempt to apply it to pre-heating my hot water inlet. By doing so I'll avoid having to make a solar collector that is capable of taking mains (in in my house mains-like) water pressure.

Currently my hot water service takes delivery of its water at around 13 deg C and then uses fossil fuel to heat it to something like 65 deg C. If I can collect some heat and store it in an insulated container, I should be able to make a simple heat exchange device to transfer that heat to the inlet water of my hot water service. If I can spare my hot water service the trouble of even a few degrees It will have been worth it. But I'm hoping to contribute more like half the energy required to make my showers hot. If I can do that I can feel a bit more confident that I can make a replacement hot water service when my existing one gives up one day.

I guess that means my official target for my inlet water temperature is a 26 deg C increase from 13 deg C to 39 deg C.

That should be easy enough in summer but it's moving towards mid-winter here so I will be very pleased if I can get even close.

6 comments:

  1. Sounds good, have you checked how much heat solar set-ups put back into the atmosphere?

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  2. Love the things you get up to. Have you looked at the Alternative Technology Association? I'm sure they'd enjoy your blog.

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    Replies
    1. I was just searching for something online and was sent here. But the result was that I noticed I seemed grumpy when I replied to your comment as well as Von's. So sorry, and thanks for the kind words :)

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  3. Do solar setups put heat back into the atmosphere?
    As far as I can tell they just move heat around.

    Any reflected light would have to be calculated against what would have happened if the setup wasn't there. I have no idea how to go about calculating that but I cant imagine it would be as environmentally damaging as say, my house.

    I suspect any less fossil fuel I burn can only be a good thing. I'm building this out of stuff that would end up as landfill so the carbon footprint of the project is the same as it was before the project.

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  4. re: Alternative Technology Association

    I'll have a look.

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  5. Von, I just re-read my reply.

    I sounded grumpy.

    I'm not grumpy :)

    ReplyDelete

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