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04-20-2015, 05:43 PM
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#21
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Senior Member
Name: Christian
Trailer: Escape 2017, 17B
Florida
Posts: 257
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Johnny, you might look at a Tesla coil, Be warned, I have no idea of the safety of the system, just friendly suggestions of things I have found interesting.
Sent from my C6530N using Fiberglass RV mobile app
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04-20-2015, 05:51 PM
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#22
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Senior Member
Name: Dave W
Trailer: Trillium 4500 - 1976, 1978, 1979, 1300 - 1977, and a 1973
Alberta
Posts: 6,926
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Air conditioners are rated in BTU, (British Thermal Units) / hr. A BTU is the amount of energy required to raise the temperature of a pound of water by one degree F. The BTU capacity for a 12VDC compressor fridge is high enough to cool a small well insulated box to near 40°F. Cooling the whole, barely insulated, trailer is a much bigger job. One that the small ~50 watt compressor in the fridge is just not up to. A small, (5000 BTU/hr) air conditioner uses ~500 watts, or ten times as much.
A propane fridge has an even lower BTU/hr value.
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04-20-2015, 05:54 PM
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#23
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Senior Member
Name: Dave W
Trailer: Trillium 4500 - 1976, 1978, 1979, 1300 - 1977, and a 1973
Alberta
Posts: 6,926
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Quote:
Originally Posted by Lisa in FL
Johnny, you might look at a Tesla coil, Be warned, I have no idea of the safety of the system, just friendly suggestions of things I have found interesting.
Sent from my C6530N using Fiberglass RV mobile app
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Ummm.... a high frequency, VERY HIGH voltage coil? I am not sure how one would utilize this for cooling.
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04-20-2015, 06:08 PM
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#24
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Senior Member
Name: Christian
Trailer: Escape 2017, 17B
Florida
Posts: 257
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My thought is to use the Tesla coil to boost the power from the solar panels up to the range of that needed for a small ac unit. Please remember, I'm sharing ideas, not expert information. I know these require research and maybe expert advice. Reply kindly, thanks.
Sent from my C6530N using Fiberglass RV mobile app
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04-20-2015, 07:16 PM
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#25
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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You can boost voltage or you can boost current, but you can't boost both. Power (watts) is power and there is no known way to increase that without using even more power in the process.
Tesla is the worlds unsung electrical genius, but even he couldn't do that.
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04-22-2015, 12:22 AM
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#26
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Senior Member
Name: Frank
Trailer: Casita
California
Posts: 260
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Looks like there is no free lunch,(,VDC vs Amps). I have a 12DC automobile radiator fan that someday, ya ya ya, I am looking to use for a trailer fan, maybe a fantastic fan look-a-like
__________________
Frank F
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04-22-2015, 07:15 AM
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#27
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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Just to save you some time.... That radiator cooling fan will sound and feel like a tornado when you turn it on and will draw 3-5 times the current of a Fantastic Fan. Might be best to opt for the real thing LOL
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04-22-2015, 10:02 AM
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#28
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Senior Member
Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
Posts: 3,640
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FrankX, I have one of those fans in the garage attic that I plan to do the same thing with, it's been up there for over 30 years. Also, when not powered by DC and is turning by the wind, it generates electricity. if you want my fan, come and get it - it's free. (Provided I can find it)
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04-22-2015, 10:11 AM
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#29
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Senior Member
Name: Dave W
Trailer: Trillium 4500 - 1976, 1978, 1979, 1300 - 1977, and a 1973
Alberta
Posts: 6,926
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Quote:
Originally Posted by Bob Miller
Tesla is the worlds unsung electrical genius, but even he couldn't do that.
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Poor man died penniless and insane, surrounded by his own inventions. He invented AC power basically. Transformers, motors......
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04-22-2015, 10:49 AM
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#30
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Senior Member
Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
Posts: 3,640
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I have a friend in Germany that was working on Tesla inventions and he has come up missing. Google. Klaus Kruger Heilbronn Germany
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04-22-2015, 11:49 AM
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#31
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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Missing
Quote:
Originally Posted by Darwin Maring
I have a friend in Germany that was working on Tesla inventions and he has come up missing. Google. Klaus Kruger Heilbronn Germany
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I think that he was last seen boarding an AsiaAirlines flight to either Borneo or Timbuktu depending on which way that pilot wanted to turn as soon as "Da Plane" was over water.LOL
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05-04-2015, 01:29 PM
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#32
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Senior Member
Name: Doug
Trailer: Trillium
California
Posts: 246
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Most of the worlds cooling systems take advantage of "latent heat". When you heat water it takes 1 calorie per gram to heat it 1 degree C, but when the water temperature reaches boiling, it absorbs 540 calories per gram without increasing in temperature and the result is steam. So you can look at steam as a huge heat battery. Run the steam outside in a copper tube and evaporate it and it gives up all that heat to the outside air. What you have done with just 1 cc of water is removed 540 calories of heat from inside. Once the water has evaporated back to water outside, it can be brought back inside through tubing and the cycle starts over again in a closed system. That is how air conditioners work, but they use freon or ammonia instead of water (works the same just better). The hard part is getting the liquid inside to boiling temperature without too much energy expenditure. One trick is that you can increase or decrease the boiling/condensation temperature by changing the pressure and that is what the compressor on an air conditioner does. The ammonia refrigerators in our trailers use another method of boiling ammonia out of water using a propane flame or electric heater and allowing it to interact with hydrogen gas to make a closed system. It is a marvel. The ammonia gas condenses in the back of the fridge to a liquid and gives up heat to the outside air (discharging the latent heat battery to stay with the analogy), that returns the ammonia to liquid form; it then runs into the inside of the fridge where it evaporates and the latent battery charges by absorbing heat out of the interior of the fridge, cooling the beer. The resulting ammonia gas is transported back out of the fridge where the cycle repeats. Hydrogen gas and water and the heat from an electrical or propane heater combine to manipulate this process with minimal energy.
So the processes of the swamp heater are well known, you just have to arrange it in some sort of closed system which doesn't require too much outside energy to keep going.
Sorry for all the words but this is such an interesting topic, and the beer stays cold.
Sent from my iPad using Fiberglass RV
Doug L
__________________
Doug
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05-04-2015, 01:52 PM
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#33
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Senior Member
Name: Doug
Trailer: Trillium
California
Posts: 246
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For those of you that love this stuff, a little more detail. In the ammonia fridge in our trailers, there is no compressor and being a closed system everything is at the same pressure (about 300psi). So how does the ammonia boil in one part of the system and evaporate in another?? Another trick is to utilize Dalton's Laws. When you mix 2 or more fluids, the total pressure is the sum of the individual (partial pressures). In the fridge everything is at one total pressure, BUT in one part of the fridge the ammonia gas is mixed with hydrogen and so the ammonia acts as if it were at a lower than 300psi pressure because it represents only part of the total pressure, the hydrogen is the other part and the sum equals 300 psi. So the ammonia boils at a lower temperature...because of the presence of hydrogen. After the boiling, which sucks the heat out of the beer, the ammonia gas is absorbed into water. Ammonia and water have an affinity for one another and so combine when they meet one another. The water/ammonia solution is now heated by the propane flame, which separates the ammonia gas. The ammonia gas now is separated from the hydrogen (by the water), so behaves as if it is at 300psi as there is no other substance to use up partial pressure. That promotes condensing (things condense better at higher pressure), and in the condensing, the heat is given up to outside air. Is that a wonder or is that a wonder? I can't drink a beer at a picnic table without toasting John Dalton.
Sent from my iPad using Fiberglass RV
Doug L
__________________
Doug
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05-04-2015, 02:00 PM
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#34
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Senior Member
Trailer: Class A Motorhome
Posts: 7,912
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Clip: "So the processes of the swamp heater are well known"
"Swamp Heater" I thought that we were talking about something entirely different????
As I only have an 18th grade education, maybe you can boil your information down to my level of understanding.
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05-04-2015, 02:04 PM
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#35
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Senior Member
Trailer: Escape 17 ft
Posts: 8,317
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I was thinking that exactly what Doug L has done. I won't remember any of it, but I think I understood it.
__________________
What happens to the hole when the cheese is gone?
- Bertolt Brecht
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05-04-2015, 02:16 PM
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#36
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Senior Member
Name: Dave W
Trailer: Trillium 4500 - 1976, 1978, 1979, 1300 - 1977, and a 1973
Alberta
Posts: 6,926
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Doug, Thank you for that concise explanation of absorption refrigeration. A dark art to most.
It should be noted that the BTU value that they achieve is comparatively low compared to a compressor style heat pump.
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05-04-2015, 02:31 PM
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#37
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Senior Member
Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
Posts: 3,640
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Dleverton, Whild building this unit, why not make Moonshine with the heat part and make some $$$ in the process.
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05-04-2015, 02:34 PM
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#38
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Senior Member
Name: Paul
Trailer: '04 Scamp 19D, TV:Tacoma 3.5L 4door, SB
Colorado
Posts: 1,845
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Quote:
Originally Posted by dleverton
...... Is that a wonder or is that a wonder? I can't drink a beer at a picnic table without toasting John Dalton.
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Some of the best brains worked on this long time ago. Don't for get Albert Einstein and Leo Szilard, who have a patent on absorption refrigeration. Raise a bierstein for them as well.
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05-04-2015, 03:04 PM
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#39
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Senior Member
Name: Doug
Trailer: Trillium
California
Posts: 246
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I like the still idea. Cool your trailer and get moonshine as a by product.
Sent from my iPad using Fiberglass RV
Doug L
__________________
Doug
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05-04-2015, 03:09 PM
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#40
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Senior Member
Name: Doug
Trailer: Trillium
California
Posts: 246
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Hey Paul. I never knew about Einstein and Szilard being involved. There is a Wikopedia write up. Thanks for that, and I've finished the Dalton beer, so I'll open another to toast E and S.
Sent from my iPad using Fiberglass RV
Doug L
__________________
Doug
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