Jump to content

Power and a bottle of wine

Recommended Posts

  • Replies 30
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Stick it inside a thick woolen sock. Dip it in the ocean. Hang in the rigging. Repeat 2 or 3 times. Done. Zero amps. It's called the latent heat of evaporation. Works equally well with beer.

With a sock in the rigging the only energy expended is lifting from the waterline.

Just drink red and the whole problem goes away.

I'll ask the 2 lads who may or may not get to see their families this evening.


Wiring my boat and making me drill lots of holes so they can add lots of weight.


They are playing very much on the edge........  I do have a very big backyard and a spade.

Link to post
Share on other sites

q(J) = m x C x dT where q = energy in Joules, m mass of stuff being "heated" in grams, C = specific heat of stuff (j/g/deg.C) and dT = change in temperature.

assume 750ml wine = 825g (sg ~1.1); glass bottle = 400g; C = 2.3 - 2.7 J/g/deg.C wine; = 0.5 - 0.9 J/g/deg. C glass


therefore  you need [825 x (2.3 : 2.7) x 13] + [400 x (0.5 : 0.9) x 13 = 27.3 - 33.6 kJ of energy plus losses (depends on your cooling method)


someone else can finish this - got a meeting to get to

Link to post
Share on other sites

OK so being a bit pedantic and nerdy here, but the formulae is correct if you do not factor in losses. Inefficiency is the hardest part to add to the equation, due to so many variables. The only way it could be factored in would be to run the cooling unit for a time to get the fridge down to temperature, then measure the energy used over a given time to see how much energy it takes to maintain the Fridge box at that temp. Then add in that to your equation as a loss.
And the efficiency of Cooling units can be wildly varying between installations with some having terrible inefficiency figures. Add into that, the type of unit creating the cooling. Compressor and is it engien driven or electric and is the electric inverter controlled etc etc.

Link to post
Share on other sites

Indeed wheels, but the question was how much energy does it take to cool the wine.

Not keep it cool, where the losses from the fridge (or whatever) must be considered. In reality it would not surprise me to have to take twice what the formula says from the battery, even starting with a cold fridge, to allow this. Battery, chemical energy, to mechanical (compressor etc), losses in the heat transfer from the refrigeration solution to the cooling method(eutectic, thin plate, etc) and the inefficiencies in the insulation etc.

As far as I know, the very fastest way to cool something is in a liquid that's below zero. Like salt water, water anti freeze solution, etc. Liquid because it contacts the whole bottle (in this case) and has much better heat transfer than gases. That's why a salt ice slurry is better than just freshwater ice...

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...