Ideal heat exchange for welding cooler?

  1. geb

    geb 5

    I arrived here following links to "heat exchange".

    I've got a small (200amp) tig welder and would like to move up to a water cooled torch. I'm building my own cooler in my workshop. I'm challenging myself to fit a cooler into the smallest package possible, the only limits being my pocketbook and lack of formal knowledge of thermodynamics.

    I've sourced a very compact 8x4 inch 115vac vane pump. I've breadboarded circuits for flow and temp sensing/display. I've got the plumbing down. I have basic dimensions in mind. System needs to circulate coolant at approx 1 l/min and 50 psi (20psi working/50psi design pressure). All wetted parts must be electrochemically compatible.

    Welding coolers have typically made use of finned tube "condenser" type exchangers in order to handle system pressures exceeding 60psi. Below is a typical setup. The exchanger (no.4) is approx 12x12x2 inch.

    This design has not seen much change since the '40s. The pressure consideration can be sidestepped by placing the radiator before the pump, and some designs do just this. There is quite a bit of water mass employed in heat dissipation in these as well, with reservoirs of from 4 to 15 gallons. Some coolers use only water mass in fact. Heat dissip is usually from about 8000 to 16000 btu/hr.

    I'd like to see how small I can make a heat exchanger for my shop that can manage 8000 btu/hr. Maybe shoebox sized, with a minimum of coolant reservoir space, perhaps one or two liters. I've looked at peltier devices, finned extrusions (maybe make the entire chassis an exchanger), 'stacked tube' type of radiators for cpu cooling in computers, and automotive heater cores.

    If you were going to try to dissipate 8000 btu of water (approx 60 to 70C) at 1 l/min (typically a VERY low flow for most exhange calculations) in a chassis approx the size of a shoebox, what devices would you be looking at? (without resorting to NASA grade componentry).

    Thanks so much for any suggestions.
  2. jcsd
  3. geb

    geb 5

    Ok, I'll ask something a bit less involved.
    Can anyone help me locate a source for the range of heat that a typical water cooled TIG welding torch head and conducting cable (this also is cooled by the fluid) produces and is drawn off by the fluid?

    It is difficult for me to grasp the idea that a tiny brass body that is heated conductively by a tiny 3/32 inch (albeit red hot at the tip that is one inch away from the water cooled collet body) and by the radiant heat of a welding arc one inch away, can possibly load 10000 BTU/hr into a cooling system. Thats approaching the total heat output of a small wood stove! The vast majority of the heat at the arc is dissipated into the surroundings and the work. All the welding coolers I see commercially are rated from 8000 to 16000 BTU/hr, with 1/2hp bronze bodied pumps and very large water reservoirs.

    Isn't this fantastic overkill for a non industrial arc welder in the 1-300 amp range?
  4. I have seen other people using heater cores with a fan to cool it. You could phone a welding shop and ask what they use.
  5. geb

    geb 5

    Last edited: Dec 14, 2008
  6. geb

    geb 5

    I've asked a number of the 'staff' to have this post removed. Please advise me how this might be accomplished. Thank you.
  7. geb

    geb 5

    I've looked around. There seems to be activity going on elsewhere here. All I seem to get are tumbleweeds drifting across my field of vision. Hello? Anyone here?

    Please respond.
  8. If you can figure out a way to build a transformer that will give you the necessary energy at the torch head without generating all that waste heat, now that would be something. The trouble, is that transformers for welding machines haven''t seen much change since Edison and Tesla.
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