I could use a good butt chiller. Even when I had working air conditioning, I would often get out of my car with my back covered in sweat. I’ve thought about getting one of those beaded seat covers that are designed to keep you cool, but at 6’2" tall, I can’t afford to give up head room in most vehicles.
Thinking about this scenario, it occurs to me that, when an engine is cold and warming up, you’re supposed to drive it gently until everything is nice and warm. This helps extend the life of the engine and avoid problems. For this reason, I wouldn’t want to run an electric heater, taxing the alternator and making the engine work harder than it has to.
There really is no substitute for a good block heater, and with all the new automotive accessories out there, it shouldn’t be difficult to install and run one. I recently purchased a solar trickle charger for my car, and along with it, I bought an adapter that will allow me to connect a USB device to the solar charger so I can charge my cell phone the next time the power goes out, like it did after Hurricane Matthew blew by our area.
Even if you can’t park your car in a garage or a driveway and plug in a block heater (like if you live in an apartment), there ought to be technology available that will let you connect a block heater to a solar panel of some kind. The one I got doesn’t need much light to work, so one might consider parking under a street lamp to see if that gives it enough power at night. Light from a street lamp and from the winter sun on an overcast day might not be enough to give you warm air right at startup, but if you buy the largest solar panel available, it might be enough to keep it warm enough that you get warm air from engine heat faster than without it. Battery Tender makes a 15 watt solar charger that might do the trick. It’s made for outdoor use, so you could even mount it on the roof of a truck.
Problem is, solar panels that would fit on a car would put out a small fraction of the power needed to run a block heater. And worse, you’d most need the block heater to do its thing over night - notice a problem?
Yep, I addressed that.
15 watts would be the equivalent of a candle. on the ground. 6" under the pan. Depends on where you live but most cold places need something on the order of 600 or preferably 1500 watts or it will be like whizzing into the wind…
Parking under a street light will generate a tiny fraction of the power that the sun would, which is a tiny fraction of the power needed to warm an engine in bitter cold. Not gonna work…
Wouldn’t an engine with a 15 watt block heater be warmer than an engine with no block heater? Wouldn’t it reach operating temperature sooner than one with nothing?
I’m just brainstorming for ideas for apartment dwellers. If anyone else has a better idea, I’d like to know what it is. Putting down other people’s ideas is easy. Coming up with better ideas seems to be a bit of a challenge.
Technically yes, but picture standing naked outside in a blizzard, and someone touches your big toe with the corner-edge of a heating pad… You gonna be noticeably warmer? 
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Having spent just enough time in the cold to appreciate life here in the south my inclination is to tell those living in the cold to appreciate how lucky they are that cars these days can be depended on to start quickly and in ‘no time at all’ become warm enough to drive. Starting fluid, 24 volt starting systems, chokes on carburetors, etc., were a pain not too long ago.
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2008 and up F250-550 super duty diesels
have
Rapid-Heat supplemental cab heater
available.
also see ; http://emissions.borgwarner.com/taxonomy/term/36/all
Electric heat is no more efficient than the prime mover that cranks the alternator that supplies that electricity. For every BTU of heat that comes out of your electric heater, one to two BTUs of heat went out of the smokestack and condensers at the power plant.
In theory yes. Air at -40 still has plenty of heat in it.
In practice, I suspect it would be very difficult to make a cost effective heat pump that would work well at those temps.
This thread reminds me of an old riddle:
Q: Which travels faster - heat or cold?
A: Heat does, because it’s easier to catch a cold.
I use a block heater on a regular basis, not sure about the current one, but the one I had in ND was a 130 watt draw, and would shut itself of at 35 degrees, so I was told by the installer. I have not noticed a significant difference in how fast the cabin heats up, just how much better the engine starts in 15 degrees or less.
The cold does not bother me in the car, Guess I am dressed warm enough.
I did have a work car with heated seats, they were great, but evidently did not make that big of an impression because last car for wifey did not even think of looking at that option, will next time for her though.
Loved the Studabaker on the farm story, but why drive it into a snowbank? @Rod_Knox extra insulation?
Got a big engine turning, how about a friction type device for extra heat? 2 plates of metal or a brake pad or something in contact spinning opposite directions?
Driving into a snow drift kept the car from getting coated with ice. When pushed out of the snow it could be swept off. And it was rare that the car was driven especially in the winter so if left out in the open it would have become an igloo it seems.
It strikes me that this is a solution in search of a problem. I live in an area with cold, snowy winters. The current heater set up works fine for us. Up here you either remote start your car 10 minutes before you leave or you go outside, start your car, and sit for ten minutes until you have heat (so you can clear the windows). Instead of adding expensive, horsepower stealing, emissions causing electric heaters that only some people will need, it makes MUCH more sense to have people who live in cold climates simply purchase a remote starter. Problem (if one exists) solved.
Agree. Seat heaters, steering wheel heaters; are all electric resistance heat. Now, if the driver wants his feet and ears warm too, just get a remote starter and arrive late behind the wheel. Car makers have a way of offering the easiest solutions first.
Essentially, the bigger the hill you have to pump heat up to the top of, the more energy it takes to pump that heat. Pumping heat from 50 F to 80 F is a much smaller uphill than pumping heat from -40 to 80 F.
Using a heat pump to boil water is another example of heat going up a big temperature hill. So much energy is required to pump room temperature heat up a temperature hill that big that you might as well just use resistance heat.
On the other hand, if you are pumping heat downhill, from a hot place to a cold place, the heat pump provides energy instead of consuming it. A steam engine is a heat pump going backwards and the bigger the downhill, the more of the thermal energy can be turned into mechanical energy.
B.L.E:
Good point wrt 50F to 80F vs -40 to 80F. I definitely agree with you about the energy required for a heat pump to raise the temperature over that range.
I’ve forgotten my college equations for this, but suspect the amount of energy needed for a heat pump to raise -40 ambient air 30 degrees is the same or close to the energy needed to raise 50F ambient air 30 degrees.
Going back to the original question:
can a heat pump actually produce heat when the ambient temp is -40*?
do you agree there’s plenty of heat in -40* air and that it is possible for a heat pump to produce heat from it?
It’s not the rise in temperature but the ratio of temperatures that counts. In order to get the temperature ratios correct, you have to convert to an absolute temperature scale, where zero=absolute zero.
The most commonly used absolute scale is the Kelvin scale but the Rankine scale is also perfectly good, sometimes it’s simpler to convert Fahrenheit to Rankine by adding 459.67 than it is to convert Fahrenheit to Celsius and than converting Celsius to Kelvin by adding 273.15.
The ratios of the temperatures will still be the same no matter which way you do it.
An ideal heat engine’s conversion of heat to energy, or vice versa is expressed by the equation (hot temp-cold temp)/hot temp.
If the hot body is at 80 degrees F and the cold body is at -40 F, first we convert to absolute temp by adding 459.67 to those temps. This converts Fahrenheit to Rankine temperatures. The Rankine scale is the Fahrenheit counterpart to the Kelvin scale.
So we do the math…-40F = 419.67R
80 F= 539.67 R
(539.67-419.67)/539.67 = .2224 or 22.24 %
That is, in an ideal (Carnot) heat pump pumping heat from -40 to 80 F, 22.24% of the heat output would be from the energy input and the rest, 77.76% would be from the heat that was pumped from the cold place to the hot place.
This of course is the theoretical limit, a real word heat pump would likely be a bit less efficient, maybe 30/70 or 40/60 or something like that.
The problem is that if you use a gasoline engine to power that heat pump, that gasoline engine’s heat to energy conversion is likely to be around 25 to 30%. So if you have an engine that delivers 25% of the fuel’s energy to the heat pump, which then pumps 75% of the fuel’s energy plus the 25% energy input to the hot space, you might as well have just burned that fuel in the hot space to heat it.
By the way, if you are pumping heat from 50 to 80 degrees, 5.556% of the output heat is from the energy input and 94.44% is from the heat pumped from the cold area to the hot area. That again is an ideal heat pump, real world is likely to be less.