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MEMPHIS91 07-26-16 04:45 PM

Thanks Steve, it does drip very well, slower during the hotter parts of the day. It runs for a 9 hours a day and pulls out a good 2+ gallons.

I what to play with the super heat, any idea on adjusting this txv? Turning in = less superheat?

MEMPHIS91 09-05-16 10:26 AM

UPDATE: Thing been crazy busy around here.
The dehumidifier is still working great. Even on the hottest days my power usage is near 25 kwh. And that is in a all electric 2,400 square foot home.

But I have been thinking of a HUGE design flaw in the unit.
Follow with me. The inside coils (evap in this set-up) are 3 tons, BUT they were built for flow. Meaning after the metering device (now TXV) it splits 4 ways and comes back into one line before leaving the unit. What this means is with the 6 times to small compressor trying to push enough gas though the coils I am not going to get perfectly even flow through all 4 passages ways. Which means that one way will flow the quickest and make the txv bulb read "cold enough" to start backing the gas off. So what I have found is that 60% or so of my coils are not cold enough to condense. MEANING that I'm loosing a LOT of surface area and 60% of my air is just wooshing (<redneck for air moving really fast) through the coils doing NOTHING. Also it is giving me "false" superheat readings because I could be moving a lot more gas but superheat readings are saying I am flooding the evap when really I'm only flooding 1/4 of the evap. I really don't like this. My idea? Hack this baby apart and make ONE single path all the way through the evap coils.

I just wanted to post this and get everyone's thoughts. I would take to much work but it would mean building the recovery unit that I have been putting off, because that is a lot of propane to waste if I don't.

Thanks guys!

jeff5may 09-06-16 11:22 AM

I can't really see any good pics of your indoor coil. What is usually done to accomplish even flow is simple. The manufacturers put some sort of restriction in each branch of the circuit. The more modern units have a distributor in them, which works just like a shower head. Older stuff has cap tubes of equal length feeding branches. Post #32 shows that the A-coil had this on it at one time, but I can't tell how it got modded when the TXV went in.

The main goal here is to have a constant pressure drop between the TXV outlet and the beginning of each branch of the split flow through your evaporator. It doesn't take much pressure drop to create a self-equalizing set of branches. The pressure drop will throw off your TXV, though, if it is more than a couple of PSI. In this case, you want to use an externally equalized TXV. The equalizer pipe taps into the discharge side of the evaporator so the power head can sense the pressure drop directly.

If your TXV is internally equalized (no equalizer line), and you don't have lots of pressure drop in the distribution piping, you can simply adjust the valve for proper superheat. Less spring pressure (looser) will reduce your superheat and vice versa.

MEMPHIS91 09-07-16 05:00 PM

I left the distributor on the A coil. But it is NOT equal at all.
Is there anything wrong with my idea?
The TXV is internal equalized, I will look into tuning the superheat at the TXV some as well.
Also what about applying a small/slight crimp to the couple of cap tube lines from the distributor that are the coldest? Forcing more gas to the rest of the system?

jeff5may 09-08-16 02:23 PM

You've done this kind of experimentation before. You never know what's going to happen until you try. Just remember to be prudent with the crimping tool. Once the deed is done, you can't just go back to how it was.

Also remember that there is a fundamental difference between maximum cooling capacity and maximum dehumidification. Especially since you increased the evaporator airflow.

jeff5may 06-07-20 10:43 AM

Not trying to resurrect a zombie thread here, but I happened upon a YouTuber who has built his own desiccant air conditioner. If this link dies, search for Tech ingredients solar air conditioner.

Initial proof of concept design:

Improved and simplified design:

The author states that the cop of his system is roughly double that of a standard window air conditioner.

MEMPHIS91 06-07-20 10:52 AM

Epic! Thanks for the links!
I've got projects I need to share with ya'll!

Daox 06-07-20 02:15 PM

I recently watched that as well and its very interesting!

Fordguy64 06-08-20 09:33 AM

Memphis i'm excited to see what you have to share!

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