[Electric Boats] Re: 12V Accessories (Refrigeration)

 

Hi, Kirk, thanks for the response......sorry but I don't understand the reference to 'tons'.

I realise that an auto compressor creates cold quickly, and that I don't need that, but surely the HP required at, say, one 20th or one 50th of the RPM is less than at the speed the compressor is driven by a car engine?

 

I suppose a better question I should have asked is "Can automotive AC systems work at lower RPM, and if so, what are the RPM limits if any?"

 

Maybe I ought to just try turning a car compressor with a ratchet wrench, but they tend to have little room around them.

I know that at idle, they produce frost on exposed pipes.

And I know that they are power hogs at the design speeds driven on a vehicle.

What I don't know is if the losses at lower outputs exceed the production rates at those same outputs, assuming reasonable heat insulation.

 

The solar panels I have will have no spare capacity most of the time, but if the HP requirement is low enough, the cooler/fridge application might lend itself also to pedal power - any electricity savings obviously represent increased range and/or lower battery discharge levels for propulsion.

It might be possible, too, to combine a compressor system with a Peltier system, that could be used when moored etc. and when there are watts to spare, but I am currently not sure if various charging types, (ie solar and wind and backup ICE) can be combined for simultaneous use to keep the batteries 'up'.

 

John

 

 

  Re: 12V Accessories (Refrigeration)     Sat Oct 20, 2012 1:50 pm        (PDT)        . Posted by:   "Kirk McLoren"         kirkmcloren     you lost it with small. An automobile compressor is sized, depending on application, at 1 to 2 tons. Lots of glass in a car and metal conducts well also. Rapid draw down is important. A sealed compressor with 1/8 that capacity will keep your cream cool. Assuming 50% efficiency mechanical work to electricity and then electricity to mechanical work you are at 1/4 horse versus 1 or 2. Besides in most warm places there is reliable sun. photovoltaics to battery to dedicated inverter is smaller and more reliable.  My 2 cents.       Will Rogers quote: "Stupidity got us into this â€" why can't it get us out?"   

 

  --   http://www.fastmail.fm - mmm... Fastmail...  

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