Expansion valves vs capillary tubing?

AirConditioner · 11-19-15, 09:40 AM

I'm building a very simple experimental water heating/cooling system just to practice and test various ideas before I build something larger.

I have a 5000 BTU R22 air conditioner, less the R22. (damaged condenser) I'm going to remove the compressor and attach a 25' coil of 1/4" copper tubing for both the evaporator and condenser, each of them simply dipped into a 55 gallon drum full of water. One drum will get hot, the other will get cold. It will be charged with propane instead of R22.

My question is about the expansion valve. It currently has a long capillary tube, and if I am thinking correctly that will no longer be sized correctly if I modify the evaporator and condenser, right?

I could:
1. Save the existing capillary tubing and use it with the new system.
2. Modify the capillary tubing to make it work with the new system.
3. Replace capillary tubing with thermal expansion valve.

If I chose option 2, how do I know how to make it the right size? Trial and error? Should I just make it longer or shorter until I get the desired results?

If I chose option 3, what happens if I use an expansion valve rated for more BTUs than my compressor? Most of the ones on ebay are a ton or more, not 5000 BTU.

11-19-15, 09:40 AM	#1
AirConditioner Helper EcoRenovator Join Date: Apr 2015 Location: US Posts: 42 Thanks: 5 Thanked 1 Time in 1 Post	Expansion valves vs capillary tubing? I'm building a very simple experimental water heating/cooling system just to practice and test various ideas before I build something larger. I have a 5000 BTU R22 air conditioner, less the R22. (damaged condenser) I'm going to remove the compressor and attach a 25' coil of 1/4" copper tubing for both the evaporator and condenser, each of them simply dipped into a 55 gallon drum full of water. One drum will get hot, the other will get cold. It will be charged with propane instead of R22. My question is about the expansion valve. It currently has a long capillary tube, and if I am thinking correctly that will no longer be sized correctly if I modify the evaporator and condenser, right? I could: 1. Save the existing capillary tubing and use it with the new system. 2. Modify the capillary tubing to make it work with the new system. 3. Replace capillary tubing with thermal expansion valve. If I chose option 2, how do I know how to make it the right size? Trial and error? Should I just make it longer or shorter until I get the desired results? If I chose option 3, what happens if I use an expansion valve rated for more BTUs than my compressor? Most of the ones on ebay are a ton or more, not 5000 BTU.