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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Scott & Heather on November 25, 2015, 09:54:35 AM

Title: 24 volt electric heaters
Post by: Scott & Heather on November 25, 2015, 09:54:35 AM
Can I have your thoughts on these? Could I run one or two in my bus?

http://www.aircraftspruce.com/catalog/eppages/heaters242500.php


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Title: Re: 24 volt electric heaters
Post by: bevans6 on November 25, 2015, 10:10:29 AM
Sure.  They would draw (the biggest one, 1KW at 24 volts nominal) around 42 amps and would be the equivalent of a small ceramic cube heater (which is kind of what they are) on "medium".  If your engine and the big 50DN is running, no problem.  One would draw down my battery bank in around 3 hours.  Significantly more efficient than running a heat strip or a cube heater through an inverter from battery power.  Problematic if you are on a pole and trying to run them from 120VAC - you'd need a lot of charger to keep up.

Brian
Title: Re: 24 volt electric heaters
Post by: HB of CJ on November 25, 2015, 10:53:21 AM
Very expensive for the heat provided.
Title: Re: 24 volt electric heaters
Post by: Scott & Heather on November 25, 2015, 11:56:32 AM
Ok. So is the biggest one there really putting out 18,000 BTU? That can't be right...


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Title: Re: 24 volt electric heaters
Post by: Iceni John on November 25, 2015, 12:11:45 PM
The last line of the blurb intrigues me:  "RuCar ... are up to 300% more efficient than standard alloy heater elements".   How can one type of simple resistive load such as a heating element be "more efficient" than another?   Aren't all electric heating elements intrinsically 100% efficient, assuming they don't make noise or vibrate or produce light?   Does this mean that a "standard alloy heater element" (whatever that is!) is no more than 33.3% efficient?

Mind you, even if it were only 1% more efficient, it's still technically correct to say it's "up to" 300% (or whatever number you want).

Sounds like phooey to me.
John
Title: Re: 24 volt electric heaters
Post by: Scott & Heather on November 25, 2015, 04:04:24 PM
^ I think I concur. 18,000btu out of a 1000 watt 24volt heater just ain't quite right. Oh well.


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Title: Re: 24 volt electric heaters
Post by: belfert on November 25, 2015, 07:04:12 PM
Electric resistance heat is already 100% efficient.  A 1000 watt electric heater should produce about 3,400 BTU.  The only way you're going to get 18,000 BTU out of 1000 watts is with a heat pump, or some new technology for electric heating that the manufacturer invented.
Title: Re: 24 volt electric heaters
Post by: Iceni John on November 25, 2015, 07:56:43 PM
Quote from: belfert on November 25, 2015, 07:04:12 PM
Electric resistance heat is already 100% efficient.  A 1000 watt electric heater should produce about 3,400 BTU.  The only way you're going to get 18,000 BTU out of 1000 watts is with a heat pump, or some new technology for electric heating that the manufacturer invented.
Got it!   The "RuCar" heating element is a thinly-disguised Ruthenium 106 isotope, with a half-life of about a year.   This heating element is claimed to have a life of 10,000 hours  -  that just happens to be slightly more than a year.   Coincidence?   And the Car part of RuCar is because it's for vehicles.

Easy, problem solved, that's how it gives off 18,000 BTU from only 1,000 W.   Isn't science wonderful?   See, all it needs is a few busnuts to solve this conundrum.

John
Title: Re: 24 volt electric heaters
Post by: bevans6 on November 26, 2015, 01:46:42 AM
Quote from: Iceni John on November 25, 2015, 07:56:43 PM
Got it!   The "RuCar" heating element is a thinly-disguised Ruthenium 106 isotope, with a half-life of about a year.   This heating element is claimed to have a life of 10,000 hours  -  that just happens to be slightly more than a year.   Coincidence?   And the Car part of RuCar is because it's for vehicles.

Easy, problem solved, that's how it gives off 18,000 BTU from only 1,000 W.   Isn't science wonderful?   See, all it needs is a few busnuts to solve this conundrum.

John

It's on the internet, it must be true!
Title: Re: 24 volt electric heaters
Post by: luvrbus on November 26, 2015, 02:28:34 AM
I have seen those vacuum sealed RuCar heating elements before but I don't if they work are not aren't they used in the HVAC system on jet liners for heating ?