tomw wrote:
I think if you live on the western side of CA, OR, or WA air cooling is fine
for normal ev use such as driving less than 100 miles per day and charging
at level 2 EVSEs. If you live in a very hot place such as AZ then liquid
cooling may significantly improve pack life.
It doesn't matter whether you liquid-cool or air-cool (or even
solid-state-cool) something -- all that matters is the end-temperature
you reach. In each case, you are ultimately dumping the excess heat into
the surrounding air, anyway.
Air cooling is typically the cheapest and simplest method. If you're not
trying to lower the temperature of something below ambient, then little
more than a heatsink and/or fan are needed. If you *do* need to lower
the temperature below ambient, it's a little trickier. You can use
compressed air (which cools as it expands). Or, seal up the pack during
the day when it's hot out, then open it and run the cooling fans at
night when it is much cooler.
Liquid cooling is what the auto companies know, so it's going to be
their first choice no matter what. It's heavier, less efficient, and
costs more, but is good at removing heat from concentrated locations.
Liquid cooling efficiency really goes down when you use it to cool
something below ambient (i.e. refrigeration).
Solid state cooling is another option. This uses Peltier coolers. Run
current through it, one side gets hot, and the other side gets cold.
Their cost and efficiency are even worse than liquid cooling, but they
have no moving parts and can be very small.
Finally, you can keep the pack cooler by simply running it at lower
charging and driving currents. This has to be the cheapest and most
efficient strategy.
--
Humanity is acquiring all the right technology for all the wrong
reasons. -- R. Buckminster Fuller
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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