Open Roads Forum

Print  |  Close

Topic: Propane Powered Air Conditioner

Posted By: myowneq on 07/21/10 08:35pm

My random useless thought for the day. Why not? The fridge can cool on propane, why not the air conditioner?


2010 F150 XLT 4x4 SCab 5.4L
2007 Grand Surveyor



Posted By: Capt.Storm on 07/21/10 09:17pm

Well..
A refer takes heat out of the box,it doesn't really cool.
It would take a huge refrigeration unit to take the heat out of a RV I would think.
It would be cool though if it would work..lol.


Posted By: SooperDaddy on 07/21/10 09:20pm

The problem with a propane powered A/C would be that as soon as you turned it on, the flame would blow out! Whoooosh!

They actually do have Natural Gas powered Air Conditioning, but electricity still has to be used for it to function.


My posts shouldn't be taken for factual data, and are purely fictional, for entertainment purposes, should not be constituted as related to scientific, technical, engineering, legal, religious, spiritual, or practical advice. After all it's FREE! Amen.



Posted By: mike4947 on 07/21/10 09:20pm

Consider the average RV fridge cools about 1000BTU's, one that would equal the 13.5 K BTU's would be about the size of a small room and consum propane at about 5 pounds an hour.


blog.rv.net Your daily guide to the Open Road

Subscribe to the daily digest

They say you learn by your mistakes, in that case I must be a genius.


Posted By: Capt.Storm on 07/21/10 09:26pm

Here's what you do.
You take that old exercise bike nobody uses and get some pulleys and belts and run it up to the compressor.
Have the better half peddle like crazy outside while you stay cool inside.
No noisy gen..but if you have shore power give her a rest now and then..lol.


Posted By: smkettner on 07/21/10 09:28pm

Get a propane powered generator to run your air conditioner.
Otherwise install fridges around the entire perimeter of the RV and open the doors


2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
675 watts solar
Send a PM if I missed something


Posted By: TXiceman on 07/22/10 05:37am

Too big and too costly.....

Ken


Amateur Radio Operator.
2013 HitchHiker 38RLRSB Champagne, toted with a 2012, F350, 6.7L PSD, Crewcab, dually. 3.73 axle, Full Time RVer.
Travel with a standard schnauzer and a Timneh African Gray parrot


Posted By: Fishinghat on 07/21/10 10:58pm

Looks like mike4947 hit the nail on the head. Simple physics, and cost vs. benefit.

Some commercial buildings are cooled by natural gas fired air conditioning units, and they wouldn't be used if they were not cost effective. The problem of downsizing these systems for home use has been cost. They are not competitive with electrically powered units in moderate and small sized homes.

So, when it comes to our coaches, the cost problem is even more pronounced. So, don't expect a gas fired air conditioner in the immediate future for your coach.


Holiday Rambler Navigator DP, Hummer, and Honda VT1100C Shadow



Posted By: 2oldman on 07/21/10 11:22pm

I guess if you don't mind waiting 24 hours for your rig to cool down, it would be ok.


Posted By: Old & Slow on 07/22/10 07:25am

Capt.Storm wrote:

Here's what you do.
You take that old exercise bike nobody uses and get some pulleys and belts and run it up to the compressor.
Have the better half peddle like crazy outside while you stay cool inside.
No noisy gen..but if you have shore power give her a rest now and then..lol.


This is the post of the day! Or the month or even the year. But, hey Cap. unless you have a good reason to put her outside, have a heart and be a nice guy, let her peddle inside the box.


Posted By: wa8yxm on 07/22/10 11:10am

Well. you could cool with Propane.. but you would need a deliver truck parked next to you for any real benefit.

Your fridge is what, 7 cubic feet..

My RV, closed is 8 foot by 7 foot by 35 feet (About) that's 280 times the volume of the fridge.. and that is BEFORE I PUT THE SLIDES OUT.


Home is where I park it.
Kenwood TS-2000 housed in a 2005 Damon Intruder 377



Posted By: ktmrfs on 07/22/10 09:15pm

possible but not very efficent.

A "conventional" A/C unit is a heat pump that just moves heat from one place to another (inside to outside o vice versa) so it can be very efficient, just the losses in the pump and compressor. you can typically get 3-4 BTU or more of cooling for each BTU consumed. (No it doesn't violate the laws of physics)

My understanding from thermodynamics is that absorption refrigeration units aren't moving heat from inside to outside but providing the cooling from the absorption unit and hence consume more energy than the provide. So, they are way less efficient than a "heat pump" which a conventional A/C unit is.


2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2004.5 Silverado 4x4 CC/SB Duramax/Allison



Posted By: Learjet on 07/22/10 09:42pm

Well... my basic understanding of physics is that we start at absolute zero, and then we added heat. So, when looking at it in this manner there is no such thing as cold, just an absences of heat. If those statements are true, the absorption refrigerator still must remove heat to reduce the temperature.

What say you?


2013 Ford F250 XLT 2wd Crew Cab 6.2 and 3.73 rear
2006 KZ Frontier 2303P-F
Dual 6 volt GC batts
Equal-i-zer
Yamaha EF2600c Tri-Fuel Gen.
Champion Model 46595- 3000/3500

sold* 2001 Hurricane 30Q Chevy workhorse
sold* 2006 Nissan Titan CC with tow package



Posted By: Capt.Storm on 07/22/10 09:58pm

Learjet wrote:

Well... my basic understanding of physics is that we start at absolute zero, and then we added heat. So, when looking at it in this manner there is no such thing as cold, just an absences of heat. If those statements are true, the absorption refrigerator still must remove heat to reduce the temperature. the absorption refrigerator still must remove heat to reduce the temperature.

What say you?

I always thought it was that way also..but I don't really "know",otherwise where does the coolness come from?


Posted By: Fishinghat on 07/22/10 11:01pm

Learjet is correct. In physics, there is only heat; more heat and less heat. There is no such thing as "cold". You can't make "cold" with electricity or gas, (except by using some very exotic metals that none of us could afford).

That means an absorption refrigeration unit must move "heat" from one place and release it someplace else, just like a compressor system.


Posted By: smkettner on 07/22/10 11:28pm

If you can figure out how to make cold rather than transfer heat you will be a billionaire.


Posted By: 96Bounder30E on 07/22/10 11:56pm

Why not just power the compressor of the A/C unit with propane instead of electricity?......I don't think the OP meant to make the RV into a refrigerator


Posted By: MrWizard on 07/23/10 12:31am

how ? propane fueled engine to drive the compressor, instead of making electricity

then you would have (3) engines in the the RV, chassis, generator & A/C ?

propane is costly and inconvenient unless you have 500gal available

our Dp has a Propane fueled Onan and using JUST ONE a/c unit during the tripple digit temps, cost me over $20 per day in propane,
I refilled twice burning 57gal in 7 days $132

I went out and bought a 50amp to 30amp dog bone adapter and started using my champion portable to power the MH's electrical needs

* This post was edited 07/23/10 11:32am by MrWizard *


Options, always have options, and the journey goes much smoother
....

Connected thru Verizon with HotSpot WiFi using a Samsung Galaxy Nexus



Posted By: 2oldman on 07/23/10 01:25am

smkettner wrote:

If you can figure out how to make cold rather than transfer heat you will be a billionaire.
I want a 'macrowave' refrigerator. One that will slow down the movement of molecules, rather than exciting them like a microwave does.


Posted By: dclark1946 on 07/23/10 06:09am

96Bounder30E wrote:

Why not just power the compressor of the A/C unit with propane instead of electricity?......I don't think the OP meant to make the RV into a refrigerator


There is not that much difference in the physics between a gas and electrical refrigeration system. Both are heat pumps that move heat from inside to the outside through a heat exchanger operating at a higer temperature than the outside temperature using some type of gas and both require work put into the system to get the gas in the right state (temperature) to dump heat to the ouside temperature. An electrical A/C uses a compressor to provide the work input to the freon while a gas unit applies heat to the ammonia to provide work input. I am not sure how the efficiences compare but as others have commented there is no low energy solution to the A/C problem and you would consume a significant amount of propane running a large burner. The delta temperature maintained by an A/C system is generally only 20 degrees while a regrigerator must maintain about 40 to 45 degrees delta so while you can compare volume of the trailer directly to the volume of a trailer it is only half as bad as you might think if you don't take the emp difference into consideration.

Dick


Dick & Karen
Richardson,TX
2007 KZ Spree 240RBS
03 Tahoe/09 F250 V10


Posted By: Burp on 07/23/10 06:20am

The OP is not too far off. I once had a house that had a natural gas powered AC. It was actually NG and electricity. It used the NG to boil/heat up an amonnia solution that cooled water. Then the cold water was circulated into the house using an electric pump. It was noisey but it worked. I am not sure how much money I was saving, that was over 20 years ago. When it broke down we had to replace it with a normal unit, they did not make the NG unit any longer.

The unit was not that much bigger than a normal AC. It did have a much larger "burner" than used in a fridge. I expected that it used a fair amount of NG, but it was cheap at that time in Southern California.

The idea may be of some use if you are trying to limit your use of electricity and propane is not too expensive. But it may be expensive.

* This post was edited 07/23/10 06:37am by Burp *


2007 Winnebago Voyage 33V (Workhorse, W20)
2008 Suzuki S83 (VS1400)

Me, the Wife , Sarah
Places we have camped in an RV



Posted By: MEXICOWANDERER on 07/23/10 08:52am

"Heating to Chill" exists.

Many large complex building use the technology.

The machine is called a Lithium Bromide Liquid Absorbion Chiller.

Lots of heat (a boiler), steam to the chiller, liquid bromide is heated then chilled by a water cooling tower, bromide expands and then is run through an evaporator.

Lithium bromide is touchy. A bit too much heat and is solidifies and clogs up the chiller.


Posted By: Old & Slow on 07/23/10 11:18am

Did we get lost in the woods.

"Propane Powered A/C" ~ Okay, transfer heat. Do we not need AC for air movement? ~~ I read it on the internet. Trucks are soon to have the option of a Chinese A/C and AC all from one small engine. No noisy big and expensive diesel engine running just to supply cooling and AC. Could it come also for the RV?


Posted By: DANWHITAKE on 07/23/10 11:55am

One person had the right answer (propane generator) dan


Posted By: myowneq on 07/23/10 05:39pm

Hi Ya'll,

Sorry to wind up and let ya'll go. I got a little busy.

I was meaning using battery to run the circulation fan, but using the propane to do the cooling. Seems it can be done, but doesn't seem to be feasible.

That sounds like the case to ya'll?

Timothy


Print  |  Close