The efficiency never drops below that of a resistive heater.
They don't do their magic much below ~10 Fahrenheit, but they will work
to below zero. They actually have a resistive heater built into the
outside unit to defrost the coils if they build up ice. I have two heat
pumps on my house in Colorado and one on the garage. They have always
worked, even on the coldest days.
BTW
There is heat in air all the way to absolute zero. (-459.67 F) At this
point, it contains no (zero) heat. The air turns completely to a solid
below about 63 Kelvin (About -350 F) so you wouldn't care. :-)
Bill D.
On 11/28/2017 9:11 PM, Alan Arrison via EV wrote:
Heat can't magically be obtained from cold air.
As the temperature drops, the pump must do a lot more work for an ever
smaller amount of heat.
Al
On 11/28/2017 11:03 PM, Bill Dube via EV wrote:
Thanks for the Wikipedia reference. Here is the link:
https://en.wikipedia.org/wiki/Heat_pump
Folks are often puzzled by the "up to 4x efficiency" of heat pumps.
"How is that even possible?" is the most common question. (And the
common sense question as well...)
Well, heat pumps do indeed deliver, typically 3x to 4x the heat as a
resistive heater given the identical wattage input, occasionally even
a bit more. They indeed work, whether you believe in the theory or not.
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA
(http://groups.yahoo.com/group/NEDRA)
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
