any Air Conditioning techs out there?

D

Drake1

New member
ok in another thread i was trying to make a home made chiller with my poor soda machine unit and it failed for my 125 gallon tank, i just found a Titanium heat changer on ebay, it has 18 feet of TI which would work perfect on my 1/3 hp compressor, i can't tell if it is a CAP or a compression valve style, i am guessing from the pic that it is a valve but i have never really delt with many different looking valves...all of the ones at work look the same and look nothing like this...what do you think..only pic i was able to get
http://reefcentral.com/gallery/showphoto.php?photo=168989 Jeff
 
Looks like a flared compression fitting to me. Standard in refrigeration equipment.
 
Like the others I've seen and worked on, it is most likely a 1/2" flare. Get a TXV with a 1/2" flare outlet and connect it directly to one heat exchanger tubes, the other side will be your suction line and run to your compressor.
 
ops sorry i saw that they were compression fittings but i couldn't tell if it had a actual valve to regulate the flow of gas or if it used the old CAP tube style to regulate the gas, but i got a better pic of it and saw that it does have a valve so now i do have another question though the heat exchanger is made for 1/2 hp pump but i only have a 1/3 older style with mp39 gas and a new 1/4 pump with 134a gas. since it has the flow valve will it still slug the compressor to much if i use the 1/4 pump? also here is a pic of the valve
http://reefcentral.com/gallery/showphoto.php?photo=169193
 
You also have to match the TXV to the type of refrigerant (choose whatever you want, as long as the oil is compatible).
 
i assume that its going to be 134a so i wonder how well it would work with a 1/4 then or if it would just a a waste of money
 
R134a is fine in this application. Your heat exchanger will be oversized, but that is ok - just realize that you will not get 6000Btuhr in cooling, you will only get what the condensing unit will provide (3000Btuhr in the R134a compressor case).

You are actually less likely to slug the compressor with this setup because the heat exchanger is oversized. On the other side, the TXV will not work properly with a cooling system that is much less than 1/2 ton. A constant pressure valve is a better choice if you use the undersized condensing unit - just set the suction pressure to correspond to 40F to 50F evaporating.

I would recommend at least a 5000Btuhr system to use the TXV with this heat exchanger.
 
Propane is an excellent refrigerant... I am work on transcritical CO2 systems so my preference lies there. Unfortuately, with CO2 the low side pressure is 500 psi and the high side can be as high as 2500 psi and I have not been able to find a titanium HX for it.

R134a gets plenty cold for this application... lets remember that he is only trying to cool water, not freeze it :)
 
<a href=showthread.php?s=&postid=7350408#post7350408 target=_blank>Originally posted</a> by BeanAnimal
R134a does not get as cold... thats all. The exchanger is oversized.... but I still don't like 134a :)

What about propane :D
Click to expand...

I'm doing something simular and considering propane. What would be the best oil to use with propane, mineral oil, POE oil or something else?
 
mineral oil or alkylbenzene

Just don;t use the propane you buy for your grill ... that stuff is not pure propane it is not a regulated mixture. You will need to get 99% or better propane.
 
<a href=showthread.php?s=&postid=7350600#post7350600 target=_blank>Originally posted</a> by cseeton
mineral oil...
Click to expand...

So, it will not only lubricate human piping, but refridgeration piping as well. GREAT! :D
 
I have read a lot about propane (AKA R290 and a dozen others).

It's a shame R11 is long gone...R12 and R22 just about gone...

What about the good old Halons.... I don't even think halon fire supresssion is allowed anymore.

Then this new RoHS crap. Refrigerants, industrial coatings, plastics, dyes, paints, etc have all dropped severely in qaulity and longevity or efficiency becuse of the greenie laws. Sadly with RoHS electronics components are next. Stuff costs more to manufacture, more to operate, and lasts 1/3 as long. I just don't see where ANY savings are. The money spent on the products, laws, enforcment, R&D etc could be better spent on cleaning up other problems. The short lifepsan of all this stuff is using more energy and resources than the problem it is fixing. Gotta love progress.
 
134a (the canadian refrigerant) will do the job perfectly. The oversized evaporator is a benefit (as noted above).

And one more thing to consider Drake, keep it simple.

Also I didn't see where you indicated the cooling capacity of your compressor, only that it was 1/3 H.P. Are you assuming that it is 1/3 ton of cooling?
 
I would honestly like to come up with a sure fire DIY plan for building these things. I am just about to rip into a fairly new window shaker. I hesitate becuase of the number of variables that are involved. Not being formerly trained in refrigeration design bothers me. I have the skills, the metnal capacity but no way to fill in some of the gaps that application specific training would provide.

For example, it's fine to know what causes the compressor to slug, but it's another thing to know how to size all of the components to prevent the problem.
 
using a cap tube, unless you really screwed it up slugging would be a tough one with this set up. temp on the evaporator is going to be pretty stable. still think best option would be a cap tube. kis

with an aev an accumulator would surely be needed. with a valve the chance exists of dumping to much coolent into the evaporator. though the aev would be more efficient.

you can increase the effciency of the cap by subcooling it.

now you just need to put it all together and have someone charge it
 
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