Hybrid Car – More Fun with Less Gas

Another reason why electric cars won't catch on. - Page 4

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Posted by Neo on August 19, 2009, 11:42 am

It is true that in extremely cold temperatures batteries do not
operate af full efficiency.
Also in extremely hot temperatures there is a risk that a battery may
Under hi load conditions a battery may generates heat and gases that
need to be dissipated;
both the Honda Insight and the Toyota Prius have static battery
cooling vents for this.

For cooling and heating the cabin the all electric Aptera uses a
Another possible albeit I have not heard of it being used for a
AC/heating mechanism  would be a Thermoelectric/ Peltier Cooler.

Posted by vaughn on August 19, 2009, 11:53 am

   Unless there have been some recent advances, Peltier heat pump systems
have lower efficiency than a good mechanical system.  Since any practical
battery car will need an AC system, making it a 2-way heat pump to add
heating capability s a logical choice compared to resistance heating.


Posted by Richard W. on August 19, 2009, 7:25 pm

If there is no heat in the outside air then a heat pump doesn't work. You
will need some sort of heating devise. Gas or electric.

My neighbor has a heat pump for his house, when it's 18 F out side his heat
bill is about the same as mine and I have an electric furnace.

Richard W.

Posted by Morris Dovey on August 19, 2009, 7:36 pm

Richard W. wrote:

I not a heat pump expert, but I suspect that there might be considerable
variation in heat pump performance. I have a friend here in Iowa who's
pleased that his highest single month heat pump operating cost has been
US$9 to heat a three-bedroom ranch home on the open prairie.

Morris Dovey
DeSoto Solar
DeSoto, Iowa USA

Posted by harry on August 19, 2009, 8:28 pm

There's heat pumps and heat pumps.   The one's trying to extract heat
from air  are going to fail in cold weather (ie 25degF or less) when
you need them. The ones we have in the UK have a heat exchanger buried
in the ground where the temperature is more constant.  ( either
trenches or a borehole)
At around 30degFoutside, the coefficient of performance (COP) is
around 4. ie you get 4x the electricity you put in  out as heat.

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