# [EVDL] How much wattage for a heater?



## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

Robert,

I live in SE Idaho which I think qualifies as a "northern" climate. I have
a 1500W ceramic electric heater installed in place of the original heater
core. My garage is unheated and I park outside (no plug in) at work. The
ceramic heater does provide some heat but it definitely is nothing like what
you get from a typical ICE heater. It keeps the windows clear even when
temps get down to single digits. My wife and I just wear some extra layers
during our short 5 mile commute to work. I know some folks in northern
areas have gone to diesel fired heaters but that has always struck me as
defeating a big purpose of an EV (i.e., reducing CO2 emissions).

I've heard of folks installing a double set (3000W) of these ceramic
heaters, and this apparently works much better. *B*ut I've also heard that
doing so has resulted in either fires or at least melt-down of the plastic
components inside the dash in some cases.

There are other options available. Check out the interesting writeup at EV
source for a comparison of some different types of EV heaters:
http://www.evsource.com/articles/heater_compare.php

But to address your basic question, I too think 20Kw sounds like gross
overkill. I'm not sure you'd really need that much energy to be
comfortable.

- Peter Flipsen Jr
http://www.evalbum.com/1974





> Robert MacDowell <[email protected]>wrote:
> 
> > I'm having a conversation with someone about the practicality of EVs. He
> > feels that EVs won't fly in northern climates, because the heater simply
> ...


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## EVDL List (Jul 27, 2007)

> Robert MacDowell wrote:
> > 20,000 watts seemed a little high to me.
> 
> You are right. It's around 1 to 2 kW. And you don't need that power
> ...


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## EVDL List (Jul 27, 2007)

20kW is more power than the BTU/hr equivalent of the gas furnace that 
heats my entire house.

Let's look at the extreme case: say the car fan runs at 100 CFM air 
flow rate and it sucks in cold -50 degree F air and puts out 100 
degree F dry air... it only takes 3 kW to do that.

20 kW would kill the occupants and light the car on fire!



> Bas Doeksen wrote:
> 
> > Robert MacDowell wrote:
> >> 20,000 watts seemed a little high to me.
> ...


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## EVDL List (Jul 27, 2007)

Hello Robert,

Living here in Montana, I have no problem in driving my EV for the 33 years 
in all kinds of weather and letting it set outside at work at at 35 below 
for 8 hours.

The EV has three heaters. One is a 1000 watt hot water heater for the 
existing heater core for defrosting the windshield, one 640 watt under dash 
mounted one on the driver side and a 840 watt under dash mounted on the 
passenger side.

These heaters were purchase from my independent auto parts store that is 
only four blocks from me. I did not have to go way out there to some 
unknown place to get these heaters.

All these heaters are 120 vac 60 hz rated where when the vehicle is park and 
plug in, it can pre-heat the EV about 15 minutes before I leave. I will 
normally turn on the 640 watt driver side heater on any time when the 
temperature is above 10 below and it's a sunny day.

All this last winter it only got down to 15 below for about a hour very 
early in the morning, so I only use the 640 watt heater all last winter.

Now you say, how to I run these heaters when I am away with the EV. Simple, 
I have a dash mounted three position 2 pole 30 amp rocker switch, which is 
use to either select the commercial power or on board 6 kw 120 VAC 60 hz 
inverter made by Dynamote back in 1985. It is design to run off a 
inverter-alternator which is a large unit that is normally use for large 
utility vehicles or cabin cruisers.

You can also get inverters that are design to run off the main battery pack.

I choose the alternator model, because we have a lot of steep hills here 
that is like a roller coaster ride. I wanted to have something to be able 
to slow or hold the speed on the down hill runs. The heater loads, electric 
power steering, pumps and fans does hold the speed down very good while I 
down shift to a 13:1 ratio gear.

The 1000 watt @ 120 V hot water heater is a 18 inch long stainless tube that 
is 2.5 inches in diameter that is normally use for re-heating large diesel 
engines. I first tested it out, by just connecting it to the existing 
heater hoses. The unit has some type of pulse type pump and a plug in 
temperature module. The problem here was that there was not enough fluid 
volume which it cause it to short cycle from ambient to boiling temperature 
in less than a minute.

So I added one of those long expansion tanks that set above a radiator or in 
a higher position design for those low slung engines. Ran larger heater 
hoses that are double insulated with that black A/C hose insulation. Also 
insulated the heater unit and tank. Now it only short cycles about every 2 
to 3 minutes.

A ICE vehicle that is design to be heated by the temperature of the engine, 
which may get up to and over 240 F. I find with my car, that the heater 
damper doors was tempering this temperature with out side ambient air. I 
rework the damper doors which are all vacuum operated, where I can 
completely close the outside air mix or allow some come in and re-circulated 
the cabin heat as you do in a home.

Only had to turn on the defroster heat only one time, and it would start to 
defrost starting at a heater temperature of only 50 F. So I adjusted heater 
water temperature to 140 F which work good.

My heaters are not on continuous while I'am on the go. It may only cycle on 
once every mile at 0 F. I work out the on cycle, by having a micro switch 
on the accelerator, turn the thermostat circuit on when I am on the down 
hill run. This way I am applying only kinetic energy from the EV and 
applying no motor or battery current at the time.

Another thing that helps to keep the inside of a EV warm in the winter and 
cool in the summer, is to super insulated it. I install several layers of 
Dow Corning Blue rigid foam on the floor until the floor was completely flat 
which took out all those deep waves. Install one inch soft foam and a 
aluminum coated plastic sheet behind all the door panels and front and rear 
fire walls. Completely cover all the foam with a high pile foam back 
carpet.

The seats surfaces are all cover with a upholster cover soft foam pillow 
tops with a high pile material over the vinyl surfaces.

Above the head liner which is also a thin foam back material, is a one of 
those 1/2 inch aluminize bubble insulation that is glue to the top sheet 
metal. There is a 1 inch space between the head liner material and this 
insulation which allows airflow between these surfaces.

The outside top over the cab and all the way down to the rear bumper, is 
cover with water proof 1/4 plastic coated foam and cover with a heavy duty 
polyester back vinyl.

The estimated R-Factor in the cabin area and in the battery compartment is 
from 12 to 25 R-Factor.

Here is a formula I use for calculating the Btu's:

Btu's = SF x u x TD

SF = square foot or area between the outside ambient air and the
inside temperature you want to maintain.

TD = The temperature difference between outside and the inside.

u = 1/R or one divided by the R-factor of the material

Btu's converted to electric heat is 1000 watts per 3412 btus loss.


Roland




----- Original Message ----- 
From: "Robert MacDowell" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, March 20, 2009 11:26 AM
Subject: [EVDL] How much wattage for a heater?


> I'm having a conversation with someone about the practicality of EVs. He
> feels that EVs won't fly in northern climates, because the heater simply
> requires too much energy. He bases this on a belief that a respectable
> heater is going to require 20kw, especially at highway speed.
>
> 20,000 watts seemed a little high to me. I have to imagine that many 
> folks
> have worked out the problem of comfortable winter heat... how do you do 
> it?
>
> Robert
> _______________________________________________
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> 

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## EVDL List (Jul 27, 2007)

LOL, most houses use 1500 Watts to heat a fair-sized room, even in cold 
climates! 3000 watts (two 1500 watt elements, like John Wayland had in his 
Datsun) would heat even a large sedan very well at 50 degrees belwo zero 
outside. And most EV's are small, so it takes less.

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]

----- Original Message ----- 
From: "Robert MacDowell" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Friday, March 20, 2009 11:26 AM
Subject: [EVDL] How much wattage for a heater?


> I'm having a conversation with someone about the practicality of EVs. He
> feels that EVs won't fly in northern climates, because the heater simply
> requires too much energy. He bases this on a belief that a respectable
> heater is going to require 20kw, especially at highway speed.
>
> 20,000 watts seemed a little high to me. I have to imagine that many 
> folks
> have worked out the problem of comfortable winter heat... how do you do 
> it?
>
> Robert
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

Well, I just talked with a few streetcar folks... they say a 40 foot long
streetcar has 10kw of heat. That's with doors getting opened & closed every
block. A 72 foot long BART car has 36kw of heat, but it hardly ever runs,
except for a short time during the beginning of the day when the car is
being warmed for its first load of passengers.

>
>
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## EVDL List (Jul 27, 2007)

> Grant Stockly <[email protected]> wrote:
> 
> > At 12:59 PM 3/20/2009, you wrote:
> > >LOL, most houses use 1500 Watts to heat a fair-sized room, even in cold
> ...


----------



## EVDL List (Jul 27, 2007)

Jeff
When a car is traveling at 60 MPH, the cold air is hitting the car at 60 MPH
( more of less) , so that cold air draws more heat away from surface of the
car ( and infiltrates more, also)

It's the same thing that happens when you stand outside in a cold wind. Now
imagine standing outside in a 60 (or 70) MPH cold wind. It would take more
power to keep warm. This effect is sometimes called "wind chill".

Phil Marino





> Jeff Shanab <[email protected]> wrote:
> 
> > >
> > > I'm having a conversation with someone about the practicality of EVs. He
> ...


----------



## EVDL List (Jul 27, 2007)

I don't understand "wind chill" inside a car unless you drive about with 
the top and windows down. ICE vehicles waste so much energy as heat 
that a source of warm air is easy. Note also the apollo astronauts 
don't complain of lack of heat on takeoff. My plan is to use 3 1kw 
water heaters to heat the liquid to 165F or so with thermostat to 
maintain temp. Using the recirculate should reduce the heat load. ICE 
vehicle systems are not set up to conserve energy the way our homes are 
but that may come in time. I'll let you know if it works next winter.
John

Phil Marino wrote:
> Jeff
> When a car is traveling at 60 MPH, the cold air is hitting the car at 60 MPH
> ( more of less) , so that cold air draws more heat away from surface of the
> car ( and infiltrates more, also)
>
> It's the same thing that happens when you stand outside in a cold wind. Now
> imagine standing outside in a 60 (or 70) MPH cold wind. It would take more
> power to keep warm. This effect is sometimes called "wind chill".
>
> Phil Marino
>
>
>
>


> Jeff Shanab <[email protected]> wrote:
> >
> >
> >>> I'm having a conversation with someone about the practicality of EVs. He
> ...


----------



## EVDL List (Jul 27, 2007)

> Jeff Shanab <[email protected]> wrote:
> 
> > Why does "especially at highway speed." have a bearing on heating load?
> 
> ...


----------



## EVDL List (Jul 27, 2007)

>> LOL, most houses use 1500 Watts to heat a fair-sized room, even in
>> cold climates! 3000 watts (two 1500 watt elements, like John 
>> Wayland had in his Datsun) would heat even a large sedan very well 
>> at 50 degrees below zero outside. And most EVs are small, so it 
>> takes less.

> BTU's are NOT the same as watts -- I'll guarantee that 300 watts of 
> heater would be more than what you could comfortably stand in a small
> vehicle!

Everything depends on your climate (mainly, the outside temperature),
and in how fast you want to warm up a cold car.

Typical car heaters produce enough heat for a small apartment. That's
because the heat is "free" (waste engine heat), and they want to warm up
the car in a few minutes (once the engine has warmed up, that is).

The high peak power is needed to warm a cold car quickly. A much lower 
average power is needed to keep it at temperature.

I converted my present EV (a 1980 Renault when I lived in Seattle. I
modified a "1500 watt" 120vac heater (which actually delivered more like
1200 watts). It worked fine for heating and defrosting in Seattle's mild
climate.

When I returned to Minnesota, it was inadequate for
sub-freezing temperatures. I changed it to use two 1500w ceramic
elements (which actually produced more like 1800w of heat) to get enough
heat to defrost the windshield on 0 deg.F days.

-- 
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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## EVDL List (Jul 27, 2007)

> David Nelson wrote:
> > Wind chill applies to any body, living or not, which is warmer than
> > the surrounding air. If the wind chill factor is say -10 degrees with
> > a relative wind speed of 60mph the effect is the same as being in
> ...


----------



## EVDL List (Jul 27, 2007)

That was at 96V, though, right, Lee?

Joseph H. Strubhar

Web: www.gremcoinc.com

E-mail: [email protected]

----- Original Message ----- 
From: "Lee Hart" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Saturday, March 21, 2009 1:05 PM
Subject: Re: [EVDL] How much wattage for a heater?


>>> LOL, most houses use 1500 Watts to heat a fair-sized room, even in
>>> cold climates! 3000 watts (two 1500 watt elements, like John
>>> Wayland had in his Datsun) would heat even a large sedan very well
>>> at 50 degrees below zero outside. And most EVs are small, so it
>>> takes less.
>
>> BTU's are NOT the same as watts -- I'll guarantee that 300 watts of
>> heater would be more than what you could comfortably stand in a small
>> vehicle!
>
> Everything depends on your climate (mainly, the outside temperature),
> and in how fast you want to warm up a cold car.
>
> Typical car heaters produce enough heat for a small apartment. That's
> because the heat is "free" (waste engine heat), and they want to warm up
> the car in a few minutes (once the engine has warmed up, that is).
>
> The high peak power is needed to warm a cold car quickly. A much lower
> average power is needed to keep it at temperature.
>
> I converted my present EV (a 1980 Renault when I lived in Seattle. I
> modified a "1500 watt" 120vac heater (which actually delivered more like
> 1200 watts). It worked fine for heating and defrosting in Seattle's mild
> climate.
>
> When I returned to Minnesota, it was inadequate for
> sub-freezing temperatures. I changed it to use two 1500w ceramic
> elements (which actually produced more like 1800w of heat) to get enough
> heat to defrost the windshield on 0 deg.F days.
>
> -- 
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in -- Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > David Nelson wrote:
> >> Wind chill applies to any body, living or not, which is warmer than
> ...


----------



## EVDL List (Jul 27, 2007)

> Jeff Shanab wrote:
> >
> >>
> >> I'm having a conversation with someone about the practicality of EVs. He
> ...


----------



## EVDL List (Jul 27, 2007)

> Mmech wrote:
> >
> > Note also the apollo astronauts don't complain of lack of heat on takeoff.
> > John
> ...


----------



## EVDL List (Jul 27, 2007)

At 05:23 AM 3/21/2009, you wrote:
>


> Grant Stockly <[email protected]> wrote:
> >
> > > At 12:59 PM 3/20/2009, you wrote:
> > > >LOL, most houses use 1500 Watts to heat a fair-sized room, even in cold
> ...


----------



## EVDL List (Jul 27, 2007)

From: Lee Hart
>> I converted my present EV (a 1980 Renault when I lived in Seattle. 
>> I modified a "1500 watt" 120vac heater (which actually delivered 
>> more like 1200 watts)... I changed it to use two 1500w ceramic 
>> elements (which actually produced more like 1800w of heat) to get 
>> enough heat to defrost the windshield on 0 deg.F days.



> joe wrote:
> > That was at 96V, though, right, Lee?
> 
> No; that was with a 132v pack. The pack sagged somewhat while driving,
> ...


----------



## EVDL List (Jul 27, 2007)

>
> Jeff
> When a car is traveling at 60 MPH, the cold air is hitting the car at 60 MPH
> ( more of less) , so that cold air draws more heat away from surface of the
> car ( and infiltrates more, also)
> 
like a fan on a heatsink, But without fins and with insulation inside, 
can it be that much of a difference?
> It's the same thing that happens when you stand outside in a cold wind. Now
> imagine standing outside in a 60 (or 70) MPH cold wind. It would take more
> power to keep warm. This effect is sometimes called "wind chill".
>
> Phil Marino
> 

Wind Chill is a little more complex, we humans hold air around us 
(surface hair) and we sweat and we have blood near the surface as a 
heatsink.

I agree it is a factor, but maybe it is more because some cars always 
pull air from the outside.

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## EVDL List (Jul 27, 2007)

Lee,
I guess your last sentence should read: 400 Watts.
Because you need to overcome 40 deg instead of 30 which
required 300 Watts in your example. 
(Power and rate of cooling is linear with temp difference.)

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Lee Hart
Sent: Sunday, March 22, 2009 2:23 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] How much wattage for a heater?



> David Nelson wrote:
> > Wind chill applies to any body, living or not, which is warmer than
> > the surrounding air. If the wind chill factor is say -10 degrees with
> > a relative wind speed of 60mph the effect is the same as being in
> ...


----------



## EVDL List (Jul 27, 2007)

> Cor van de Water wrote:
> > Lee,
> > I guess your last sentence should read: 400 Watts.
> > Because you need to overcome 40 deg instead of 30 which
> ...


----------



## EVDL List (Jul 27, 2007)

Just thinking out loud here, so someone will doubtless set me straight. =

But energywise, is an electric heater the most efficient way to heat an
electric car? My thinking is that a fossil fuel power plant may have had
40%-50% efficiency to turn coal/gas/oil into electricity. The rest was
mostly wasted as heat. But heat is exactly what we're talking about here. =

Would it make more energy sense to put a propane/gas/petrol heater in the
car and use the heat from buning the fuel directly, instead of producing
electicity that gets turned back into heat?

Waiting to have my intellectual wrist slapped.

Bill =


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## EVDL List (Jul 27, 2007)

Yes burning the fuel to create the heat directly would be 100% efficient,
but when it comes to making heat, you can do a lot better than 100%.

Theres also the option to use a reverse cycle refridgerative setup. 
Its technically possible, but I have yet to see one implemented.

Lack of heat is an interesting problem us EV'ers have.

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of [email protected]
Sent: Tuesday, 24 March 2009 2:05 AM
To: [email protected]
Subject: Re: [EVDL] How much wattage for a heater?

Just thinking out loud here, so someone will doubtless set me straight. 
But energywise, is an electric heater the most efficient way to heat an
electric car? My thinking is that a fossil fuel power plant may have had
40%-50% efficiency to turn coal/gas/oil into electricity. The rest was
mostly wasted as heat. But heat is exactly what we're talking about here. 
Would it make more energy sense to put a propane/gas/petrol heater in the
car and use the heat from buning the fuel directly, instead of producing
electicity that gets turned back into heat?

Waiting to have my intellectual wrist slapped.

Bill 

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## EVDL List (Jul 27, 2007)

Welll.......100% efficient if you have the fire and the resultant 
emissions in the passenger compartment. My natural gas heating (in 
house) is 90% claimed but does produce corrosive liquid down the drain. 
My heat pump produces up to 10 times the btu as resistance heating but 
the output drops off below 30 degrees enough to require aux. heat 
(resistance). The ICE has a great heat source but if we want all 
electric the heat pump is a way to reduce energy consumption but since 
the necessity isn't there not much is spent on development. If you have 
AC then a heat you have a heat pump minus the reversing valve and some 
component revision to make it more efficient. I don't have the 
capability but have considered, if I get my AC operating, to give it a 
try with the help of my friendly friend who is a refrigeration 
mechanic. If anyone has already done anything along this line would be 
nice to know.
JMS 



> matt wrote:
> > Yes burning the fuel to create the heat directly would be 100% efficient,
> > but when it comes to making heat, you can do a lot better than 100%.
> >
> ...


----------



## EVDL List (Jul 27, 2007)

Hi Bill,

The answer is probably: it depends.
If your electricity comes from fossil fuel in the
first place, then burning that fossil fuel in the
car to get heat is much more efficient than using
electric heating as you already indicated.

If you use electricity from a solar electric system
that has an abundance of left-over power then using
that to heat the car may be better (not likely though)
and when you do the math on enegy efficiency then the
use of a heat-pump (AirCo) in reverse may be better
than burning the energy to get heat in a resistor.
The efficiency of a heat-pump is however dependent
on the temp difference that it has to overcome, so
we are again at the answer "it depends"... on how
cold it actually is at your location.

If the temp difference inside/outside is in the
order of 10 to 30 deg then a heat pump wins easily
even when starting with half the energy after the
conversion from fossil fuel. But if the temp delta
becomes significant, then a heat pump becomes less
efficient (in pumping many times more heat energy than
you put into the device) so at some point the burning
of fossil fuel will take the lead.

Hope this helps,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of [email protected]
Sent: Monday, March 23, 2009 10:35 PM
To: [email protected]
Subject: Re: [EVDL] How much wattage for a heater?

Just thinking out loud here, so someone will doubtless set me straight. 
But energywise, is an electric heater the most efficient way to heat an
electric car? My thinking is that a fossil fuel power plant may have
had
40%-50% efficiency to turn coal/gas/oil into electricity. The rest was
mostly wasted as heat. But heat is exactly what we're talking about
here. 
Would it make more energy sense to put a propane/gas/petrol heater in
the
car and use the heat from buning the fuel directly, instead of producing
electicity that gets turned back into heat?

Waiting to have my intellectual wrist slapped.

Bill 

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## EVDL List (Jul 27, 2007)

> On 24 Mar 2009 at 2:47, matt wrote:
> 
> > Its technically possible, but I have yet to see one implemented.
> 
> ...


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## EVDL List (Jul 27, 2007)

Heatpump is heatpump, whether it pumps heat *out* and is
called an AirCo or pumps heat *in* and is given all kinds
of exotic descriptions or simply called Heat Pump, it is
the same thing every time.
I have designed electronics that needed a more friendly
environment than where it was operated. The simple
solution was a solid state heat pump (Peltier Element)
which pumps heat in when it is cold outside and pumps
heat out when it is hot outside.
Also my super-efficient electric clothes drier uses a 
heat pump to heat its interior with much less energy 
than when simply burning electricity in a heater element.
If you define efficiency as the amount of energy (heat)
delivered divided by the amount of energy (electricity)
supplied then the Heat Pump can easily be 500% efficient
because it does not *create* heat, it only *transports*
heat, so it is much smarter than the efficiency-focused
thinkers usually try to work.

BTW, super-efficient gas heaters also have efficiency
numbers above 100%, I think it is exactly due to the
condensing of moisture from the air that someone here
complained about, that gives them an extra 10% or so.
I seem to recall 105% efficiency.

Hope this clarifies,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of matt
Sent: Monday, March 23, 2009 11:17 PM
To: [email protected]; 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] How much wattage for a heater?

Yes burning the fuel to create the heat directly would be 100%
efficient,
but when it comes to making heat, you can do a lot better than 100%.

Theres also the option to use a reverse cycle refridgerative setup. 
Its technically possible, but I have yet to see one implemented.

Lack of heat is an interesting problem us EV'ers have.

Matt

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf
Of [email protected]
Sent: Tuesday, 24 March 2009 2:05 AM
To: [email protected]
Subject: Re: [EVDL] How much wattage for a heater?

Just thinking out loud here, so someone will doubtless set me straight. 
But energywise, is an electric heater the most efficient way to heat an
electric car? My thinking is that a fossil fuel power plant may have
had
40%-50% efficiency to turn coal/gas/oil into electricity. The rest was
mostly wasted as heat. But heat is exactly what we're talking about
here. 
Would it make more energy sense to put a propane/gas/petrol heater in
the
car and use the heat from buning the fuel directly, instead of producing
electicity that gets turned back into heat?

Waiting to have my intellectual wrist slapped.

Bill 

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## EVDL List (Jul 27, 2007)

> Evan Tuer <[email protected]> wrote:
> 
> > On Sat, Mar 21, 2009 at 2:34 PM, Jeff Shanab <[email protected]>
> > wrote:
> ...


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