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Thread: Walk-in Deer Cooler
09-27-2012, 11:39 PM #27
But I'm not sure if they have a 1 ton condensing unit
09-27-2012, 11:42 PM #28
09-27-2012, 11:45 PM #29
09-27-2012, 11:47 PM #30
I have tried to google it. Found nothing so far.
I installed it because he said here put this in. He and I both know I don't know refrigeration.
He built the box and I ran the wire, installed the condenser, evap, piping, etc....
I got it up and running but it wont get down to 40* where he wants it.
09-27-2012, 11:48 PM #31
I guess you can say its more of an experiment for me. I can say it works. So I did my job. LOL
09-28-2012, 12:06 AM #32
09-28-2012, 09:09 AM #33
The system matches up OK, however it simply doesn't have enough capacity to do the job.
The Bohn C-30 evaporator is rated at 3000 Btuh at a 10ºF TD, where the TD is the box temperature minus the evaporator temperature. A 10ºF TD is a good number to use for a general purpose walk-in, so for a 40ºF box you would select a condensing unit which has a capacity of approximately 3000 Btuh at a 30ºF evaporator temperature.
The Tecumseh AEA4440, which is a 1/3 HP unit, has a capacity of 3020 Btuh at 30ºF evap, so it is a good match for the C-30 evaporator.
The expansion valve should be selected to the actual system capacity in tons and not the nominal horsepower. For 3020 Btu, that would be 3020/12000 or about 1/4 ton, so a nominal 1/4 ton TXV should work.
As for the box load, there are some good calculator available or you could use a quick-select chart. Here's a screenshot of Heatcraft's quick selection guide for a 35ºF walk-in, which will give you an idea of what this box really needs.
As you can see, an 8 x 8 cooler should have a system with at least 7000 Btuh capacity for general duty. That would bump you up to a 3/4 HP unit and matching evaporator.
From the numbers posted, I can see you were measuring superheat at the compressor. For a refrigeration system you should always first set your superheat when the box is near design temp at the outlet of the evaporator close to the TXV bulb location where 6-8ºF SH is good, but no more than 10ºF. Then check it at the compressor where it should be no less than 20ºF.
Subcooling isn't of much use with a system that has a receiver because adding or removing refrigerant doesn't affect SC significantly, it just changes the level in the receiver.
09-28-2012, 09:52 AM #34
my 8x8 w/i has a 12k window shaker that I made some mods to the stat and added a evap air defrost. Works well, pull down is within an hour after start up.
Unless you are going to run this box all the time I do not think you have the pull down your buddy will be looking for, then add a hot deer or 2 and a couple guys working makes it worse.
I gave up the refrigeration world a long time ago, just speaking of my own personal box.
09-28-2012, 09:23 PM #35
09-30-2012, 09:27 PM #36
sweet...thanks for the info