Transportable low tech quick to deploy space heating

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Winter 2022 is going to be interesting in the UK, with the hanging threat of limited gas supply's and sky high prices space heat is becoming a difficult task. Saying that there are solution to this given enough time and finance to deploy them which leads us to the main problem, those that cannot change there heating source are the ones greatest effected. I think this group is Flat renters.

This is the main goal of the idea find a solution that can be retrofitted to any building without building changes, meaning a standalone device. There are many angles to take for this problem my favorite would be a heat pump with ice storage container, a great combination of energy density, transport and recharging. Though it is a complicated and expensive solution (though I would love to explore it)

Hence the EM Heat Tube. A tube filled with sodium acetate (or other suitable heat medium) with inbuilt magnet operated trigger. That can be recharged by solar or other heat source.

Goals of the project.

A single tube should have:

  • Storage of about 1Kwh thermal.
  • output of at lest 300W for a run time of 2-4 hours
  • be moveable by 1 person <25kg
  • recharged by solar or other heat source
  • be activated on demand

Solar collector:

  • be able to recharge a tube in 1 day of winter sun
  • work with no tracking
  • be passive

Tasks to research:


Calculations for heat capacity

spreadsheet - 15.06 kB - 07/03/2022 at 06:43


  • 1 × Pipe ABS or aluminum pipe to hold the storage medium
  • 1 × cap printed cap to seal bottom (PETG)
  • 1 × glue Been using Loctite EA9492 due to experience at work other epoxy will work

  • Triggers

    Tom07/20/2022 at 07:08 0 comments

    Looking into how to trigger the SAT to crystalize when in supersaturated(?) state.

    The main driver has been having a mechanism that can be activated with no pass-troughs, to aid sealing. Which lead to magnets as strong hard drive magnets are fairly easy to come by. 

    First design had a moving ring with screws in it so a magnet could pull it up, with the spring of the disk pulling it back down. While the was some success with this design it wasn't reliable. The print direction meant the 2 rings would rub over each other and cause friction and the click disk didn't have enough strength to pull it back all the time. Also small mistake in that I forgot PLA softens at a low ish temp and totally deformed it.

    Version 2 (or maybe 3 by this point) uses a single strip of metal but changes the magnet point to the side so the metal strip is the only moving part. This provides plenty of level advantage and almost no spring back resistance. There is a pivot point to concentrate the movement onto the part with the perforation to ensure maximum movement of them.

    I don't really understand what triggers the SAT it doesn't seam to be well understood. I have tried to emulate the click disks that are used in the hand warmers. An interesting side is when assembling the V1 test too much movement of the SAT and trigger was setting it off without the disk moving. Could make transport interesting.

  • Theoretical basics

    Tom07/02/2022 at 21:33 0 comments

    Initial investigations to see if we are barking up the wrong tree.


    • SAT density: 1.46g/CM3
    • SAT latent heat of fusion: 0.073Kwh/Kg (264kJ/KG low end 289KJ/KG high end)
    • 60% SAT to water solution (volume?)
    • ABS thermal conductivity: 0.1 W/m/K (SAT thermal conductivity not modeled ABS wall only)
    • SAT temp 58C

    First test pipe ( to be built)

    • 43mm OD 1.5mm wall ABS 1m long
    • 4.16Kg sodium acetate 1.91Kg water 6.07Kg total
    • 0.30Kwh
    • heat output @18C room: 257w
    • heat output @20C room: 244w
    • estimated 1h runtime

    Full size pipe

    • 75mm OD 65mm ID 5mm wall ABS 1m long
    • 11.55Kg SAT, 5.31Kg water, 16.86 total
    • 0.84Kwh
    • heat output @20 room: 166w
    • heat output @ 18 room: 175w
    • estimated 4h runtime

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