Lets talk AC again

[wmkbailey]

Oh well.

High voltage electricity powers the electric motor, generator, air conditioning compressor and inverter/converter. All other automotive electrical devices such as the headlights, radio, and gauges are powered from a separate 12 Volt auxiliary battery. Numerous safeguards have been designed into the Prius to help ensure the high voltage, approximately 201.6 Volt, Nickel Metal Hydride (NiMH) Hybrid Vehicle (HV) battery pack is kept safe and secure in an accident.

[opus]

I'd prefer to have a cooling system with its own engine. They used to have them but the name eludes me.

[lornaschinske]

Ease and costs in repair and replacement need to be kept in mind.I looked into ThermoKing since we had a big repair/installation facility in Chattanooga (only 60 miles away from us a the time). This was for our Eagle 05. ThermoKings are expensive to buy and repair. But it was for a "coach" and like everyone else, we felt the expensive shell validated the more expensive "thing". Not just the air conditioner but everything we were putting in. The reason I pulled back from the ThermoKing (other than the overall costs) was how sparsely the repair shops were spread out. I had visions of the unit pooping out on us and having to drive 150 miles (a real distance) to get to the nearest repair shop during a South GA heatwave and have to wait a week in Atlanta while the unit was repaired. At the time David was the one who was working. That was not a feasible option.

We have set the BlueBird up to where we can repair almost everything on/in it by stopping at Home Depot, Lowes, ACE, TruValue, Wal-Mart and either make repairs or replace. Because we have found one or more of these stores in almost every decent sized own on the primary highways that we like to travel on.

[bansil]

Lorna like you made mention:

We drive RV's....Residential Vehicles....nothing extreme on everyday use.....so for every day needs make sure you can fix it in any town USA!

Woop....woop....shiat I went wooop,woop again

[lornaschinske]

Originally Posted by bansil

Lorna like you made mention:

We drive RV's....Residential Vehicles....nothing extreme on everyday use.....so for every day needs make sure you can fix it in any town USA!

Woop....woop....shiat I went wooop,woop again

It saves money, time and decreases anxiety! If there's one thing you an say about me, it's that I am cheap!

[wmkbailey]

Never call me cheap, call me affordable.

[lapeer20m]

Here is a company that sells replacement refrigerant for automotive AC.....it's 85% propane and 15% butane.

http://www.coolearthinc.com/faq.htm

This is the website that convinced me to use propane as a refrigerant.

my theory on why propane isn't used more often as a refrigerant......because there is no money in it. I think that corporations like DOW work very hard to make sure the chemical they own the patent on is the one that gets used.

according to wiki, freon (r12) when exposed to heat creates phosgene, also known as mustard gas.

Phosgene may also be produced during testing for leaks of older-style refrigerant gases. Chloromethanes (R12, R22 and others) were formerly leak-tested in situ by employing a small gas torch (propane, butane or propylene gas) with a sniffer tube and a copper reaction plate in the flame nozzle of the torch. If any refrigerant gas was leaking from a pipe or joint, the gas would be sucked into the flame via the sniffer tube and would cause a colour change of the gas flame to a bright greenish blue. In the process, phosgene gas would be created due to the thermal reaction. No valid statistics are available, but anecdotal reports suggest that numerous refrigeration technicians suffered the effects of phosgene poisoning due to their ignorance of the toxicity of phosgene, produced during such leak testing. Electronic sensing of refrigerant gases phased out the use of flame testing for leaks in the 1980s. Similarly, phosgene poisoning is a consideration for people fighting fires that are occurring in the vicinity of freon refrigeration equipment, smoking in the vicinity of a freon leak, or fighting fires using halon or halotron.

http://en.wikipedia.org/wiki/Phosgene

[Malkieri]

Originally Posted by lornaschinske

It saves money, time and decreases anxiety! If there's one thing you an say about me, it's that I am cheap!

I have been called "cheap" many times by those who know and love me most..... I myself prefer "thrifty" but don't want to dress the part!

[gbstewart]

this last trip , we got into some very hot days, what we did was use a curtain behind the portable a\c , works ok keeping the cab of the bus cooler, you have to run the jenny, but that's ok the cold air is needed more then just burning a little gas in the jenny
gbstewart

[bapos]

I am interested in this thread. At first I was thinking.... UMMMM NO PROPANE IS FLAMMABLE......but the more I thought about it, some of us will have propane lines and bottles on board so the risk will be there regardless. So why not use it? I am currently going through HVAC school for residential and commercial applications. So I am seeing, reading, and experiencing those things in labs so it is exciting to maybe put them in place in my bus.


Keep the ideas going. Very interesting

[family wagon]

I'm back after an extended absence.. In the midst of that moving trip three weeks ago the bus engine died. Fortunately it had just enough speed to coast off the interstate at a conveniently-located off-ramp -- it happened in a construction zone where the shoulder was adequate only for pulling off a very skinny motorcycle. Full-size bus? Forget it!

Anyway.. based on the somewhat-favorable results on the test with the tarp curtain, I made a wall from OSB and stuck that A/C through it. I acquired some large cardboard from appliance boxes and used it to make a template of the roof and wall shape, then transferred it to the OSB. Sorry, it seems that I don't have any pictures of the OSB now. I'll add those later. For the first step I mounted the cardboard on a piece of 1x2 and got some help holding it in place. Then I held a pencil at a fixed position on the straight edge as shown and slid the pair toward the left, following the curvature of the roof and transferring it to the cardboard. I cut along that line, then moved the cardboard up and did a similar process to copy the shape of the wall.


Weather was cooler for the trip than it had been in that stretch of scorcher days when I did the tarp test. The A/C did fairly well. I did discover that the bus has more air infiltration than I would have guessed/hoped! That continual air change definitely affects the ability to cool the space. In any case, it did make things more comfortable. I'm glad I had it along.

For power, I built a little hitch mount for the EU2000. It's a piece of 2" receiver tube with a pair of 1" angle steel perpendicular to it, aligned so that the steel angle runs under the feet of the generator. I removed the rubber feet from the generator and built a spring mount: an ordinary compression spring, a washer with a little notch cut from its outside edge, a bolt welded to the washer. OK, four of the springs and 8 of the bolt thing. Rather than sit on its feet, the generator sat on these four compression springs. It stayed attached and it kept running the whole trip.

One thing I did discover: there are some ways of shutting down an A/C which can make it exceptionally hard to re-start on a barely-big-enough generator. Pushing the "power" button on this unit is one such method: I shut it down while we loaded stuff into the bus for 30-45 minutes, and then the generator couldn't re-start it. Finally it occurred to me to turn the A/C on and quickly switch it to fan-only mode. After running that way for a while.. 10 minutes, maybe (?) .. it re-started normally. My theory is that the extra air flow especially on the condenser helped cool things and reduce pressures so that the compressor could start more easily. This seems to be the same behavior as happens when the A/C automatically cycles the compressor when (if! ) the temperature set point is achieved.

[lornaschinske]

Family Wagon, you might want to increase the size of your generator or get another one and run them on a parallel hookup. 2K is not really enough to handle the compressor. It's hard on your genny and hard on the air conditioner compressor. Both are having their lives shortened. And you use more fuel running the genny at full load so much. But I'm sure you already know this... others may not.

[family wagon]

Yeah, "long term" I think I'll have to do one of those (another in parallel or a different unit entirely) because I'll want to cool the whole bus. I'm seriously considering electric cooking appliances rather than propane, too.

It's a bit of a struggle to start this 8000 BTU unit, but once going, the EU2000 handles it relatively easily. I have to turn off the "eco" mode (ie force it to idle higher) in order to get the A/C started, but once it's running, I can set the eco on again and the engine does reduce throttle while maintaining the compressor running. I think the solution is to set the A/C thermostat as low as it'll go, and open a window if it ever gets too cold inside. Kidding!

I've been tempted to try a few experiments to ease the starting -- either replace the starter capacitor as many others have done, or possibly add another motor to the circuit. The extra motor (something like a bench grinder, perhaps) could have a flywheel sized so that it starts more easily than the compressor does, and after it's up to speed, then some of its stored energy could be used to help start the compressor. But, since it's just idle curiosity and ultimately the generator situation has to change anyway, I probably won't bother with those experiments.

[lapeer20m]

Originally Posted by family wagon

I've been tempted to try a few experiments to ease the starting -- either replace the starter capacitor as many others have done, or possibly add another motor to the circuit. The extra motor (something like a bench grinder, perhaps) could have a flywheel sized so that it starts more easily than the compressor does, and after it's up to speed, then some of its stored energy could be used to help start the compressor. But, since it's just idle curiosity and ultimately the generator situation has to change anyway, I probably won't bother with those experiments.

my first thought is that the grinder/motor with flywheel method would not help start your a/c.....but a small part of me wonders if it would?