listeroid air conditioning

[oliver90owner]

soldering

Most (everyone?) first  thinks of copper pipework soldering with an open flame gas torch.  OK, there are a few circuit board solderers out there .

I have soldered petrol tanks with no problem - you just need a large soldering iron (about the size of a small shovel) and heat the soldering iron well away from the repair area.

Heat pumps

Not a refridgeration person, but do you add lubricant to the system after charging or is it already in the Rwhatever it is? 

Question: why not use propane from the LPG bottles?

S'pose I should go to an appropriate forum or google for more info....but thought I would just ask some of you experts.

Regards, RAB

[panaceabeachbum]

Not sure about the load you would have on the electrical side but the 508 at 2000 rpm is rated for 21000 btu  , sizing for ac system call for 2.5 btu per cubic foot of area to be cooled according to EPA and a couple of window unit web sites I have visited , here in florida the number is more probably closer to 4 btu per cubic foot .

  youre wanting to cool aprox 4300 cubic feet  x 2.5 = 10750 btu .  I am cooling almost an identical size building which is very well insulated and stays closed almost all the time and a 12k btu window unit is working perfectly , although if the door is opened 20-25 times a day the unit is barely suitable . I have a friend near buy thats cooling 720 sq feet with a 25kbtu unit and its an ice box all the time .

I dont know if any of this rambling helps , but looking at the numbers I would say it should work , I have a 4hp peteroid thats going to be the test bed for a very similar system .

I would reccomend you use the same evap, condenser, dryer etc that was originaly designed to work with the compressor you are using so the system will be balanced .

On another note I was talking with the ac guy next door and he reccomended fitting a much larger accumulator to reduce the run time of the compressor so the alternator can keep up with charging the batteries used to run the condense and evap fans . I wonder about using an alternator that can be switched off (maybe field not energised) while the compressor is running , to reduce the load on the engine .  I believe the compressor you want to run is going to pretty much use all avail HP from a 3-4 hp motor with the compressor spinning at 2k rpms  but since it will only need to run 10-20 minutes out of every hour the rest of the run time could be used to keep the batts charged .

another thing I was just thinking of is it might be possible to reduce the speed of the compressor to create less load on the smaller engine, I dont know at what speed the compressors become less effeciant. The sanden is a fixed displacement pump and might be fairly effeciant at lower speeds. The other side of the coin is the commpressor might rely on the off time to cool  and might not hold up well to running contionously at a reduced speed.

Another thing to consider is that the condensor is a great source for heating hot water, our home ac circulates water from our hot water tank thru a heat exchanger before the hot freon reaches the condensor coil and produces all the hot water our family needs thru the summer .

Hopefully someone will swing by thats been down this road already and can give advice to save us some time, as all my info is based on theory and math , not first hand experience.

[mkdutchman]

here is a link to someone who is/was experimenting with propane refrigerant

http://home.earthlink.net/~lenyr/refrig.htm

looks rather interesting

a word about propane, the place I work for uses, services and sells quite a bit of propane and propane products. IMO propane is a lot like the old iron we all like, it's safe as can be AS LONG AS THE USER KNOWS WHAT HE'S DOING. With propane, ignorance WILL injure you and/or cause you property damage (if you're lucky it stops there) sooner or later. I've lost track of the number of times I've seen that happen, all of it preventable

[mobile_bob]

MK:
i like the way you think!

from my perspective and knowing human nature of the typical DIY'er

usually we diy'ers cut corners whereever we can to save a buck, in materials and proper tools and anywhere else we can

the result "could" be a system made up of copper tubing flaired with a cheap or improper flaring tool, assembled with the cheap
non shouldered flare nut fittings, not enough of worse no support from vibration, and a crack will develop in the flare sooner than later.

now in the summer we keep things closes up tight, don't want to lose that cold air
if we have a small leak develop with propane, we should smell it right?
not necessarily, the human nose dulls out fairly quickly to a ambient smells, so if it comes on slowly we might not detect it at all.

but there is so little propane in the system?  oh really! what 2-4 lbs or more?
maybe we can lose a lb and not have enough loss of cooling capacity to know there is a leak.

1 lb mixed into the air in a tightly enclosed space??? i wonder what the percentage has to be in the air before you have
an explosive mixture? if you have batteries in an enclosed space it don't take  much hydrogen gas to lift the roof, blow out the walls
and otherwise make for a really bad day.

certainly there is nowhere near a lb of hydrogen comeing off the batteries in any single charge/discharge cycle?

one thing to use it in a combine cab, or tractor cab, or even a meat locker out behind the shop, or ice house
but maybe quite another if it is used in a house where humans habitate?
most especially if you are not very good with refrigeration, its practices, tooling and proper fittings, tubeing etc
most of which is not cheap and commonly available at homedepot or ace hdwe.

i think it would be interesting to use propane, but i don't wanna hear about a forum member who blew up his house, or killed himself
or his kids using it.
thats all it would take for the government to outlaw its use to the point of making it a felony for anyone caught using it if even for an icehouse out back where no one can get hurt.

jsut a thought

bob g

[panaceabeachbum]

there are already hefty regulations in place that restrict the use of propane as a home or auto refridgerant in the US . There is one commercial home AC system , made in Holland I think, That uses propane as the refridgerant but The propane never enters the house , instead it uses a heat exchanger and circulates a non toxic fluid thru the coil inside .

Built properlly i really dont see an issue , We have 2 propane hot water heaters , Central heat , stove and oven all running on propane as do many households

[mobile_bob]

properly built is the key phrase

as for hotwater tanks, ovens, cooktops, and furnaces in the house

yes but none of which run with high pressure propane circulating, all of which have pilot controlled saftey
valves as well, so if the pilot goes out, the system clamps off.

actually i would be just as leary of a diy built propane heating appliance if built using some of the methods i have seen
used by some diy'ers.

not being an alarmist, just being a realist and recognizing the limitations some of us have.

i guess having worked in hvac i know enough to be concerned, maybe ignorance is truely bliss?

somebody gets hurt and this hobby won't be as much fun anymore for any of us.

bob g

[panaceabeachbum]

good point , it wll be at somewhat higher pressures in the ac system, still very small qty were dealing with . 134 is cheap and plentiful so personaly thats what I am going to experiment with .

[panaceabeachbum]

Good to see someone else interested in casting . We are currently building a 10" cupola to pour iron

[billswan]

m bob

You said

 now in the summer we keep things closes up tight, don't want to lose that cold air
if we have a small leak develop with propane, we should smell it right?
not necessarily, the human nose dulls out fairly quickly to a ambient smells, so if it comes on slowly we might not detect it at all.

AS someone who has used propane as refrigerant in farm tractors I can guarantee you will NOT smell propane that has been in an ac unit.
It seems that the oil and or desiccant in the AC unit absorbs the onion odor or what ever it is. So when you remove it it has no smell like the normal propane used for heating.

So anyone using plane propane in AC systems BEWARE you will not smell a larger leak, at least if you do you will not be smelling it in the way you would expect.

Billswan

[panaceabeachbum]

here is a deisel driven ac compressor unit (apu) from a website another member directed me to in another thread , http://www.nextgenerationpower.com/semiapu.html

[mobile_bob]

there are several oem's of these  truck apu's around
some of which make hot water, 120vac 60hz 4kw, 3 tons of a/c, a 12volt 60 amp alternator
and some of which have a retail price of 10plus grand!

nice, neat, compact and clean,, but a bit pricey for what they are at least to me
but if i were a trucker?  where weight and size are a premium, and it is 105F like it was here in
seattle yesterday??? no problem,, 10 grand is a steal!



bob g

[panaceabeachbum]

tru , $10k is pricey , I was just pointing it out as it has an a/c compressor mounted as well as an alt , mostly just to spur more ideas on the lister driven a/c line of thought

[mobile_bob]

no problem, i too have looked at them to get idea's



why reinvent the wheel if we can learn from others products?

bob g

[mobile_bob]

the one i looked at in depth that got my interest was a kubota powered unit
that looked like a small changfa, and was abput 12hp, but
it pulled the A/C compressor, and a 4kwatt genhead, allong with the 60amp alternator
all of which probably could use the majority of the 12 hp,

what i don't remember was if it had a low rpm mode where the compressor could be driven if
there was no need for 60hz 120 power. if this was the case, you probably need a 12 hp to start with
in order to have enough muscle to pull the compressor and 60amp alternator at a lower engine speed.

bob g

[mobile_bob]

not only is it feasible but also practical and doable by a diy'er if he schools himself a bit

check out these folks for parts, manuals and support

http://www.rparts.com/

and then go build the thing



as for efficiency, take a bit more time researching and thinking through the project
time spent doing this will likely pay you back more per hour than most folks make at their regular jobs.
and if fuel goes through the roof again, efficiency becomes your friend believe me.


bob g