Question about Wine Coolerdor RH%

[WTF Over]

OK... I live in SoCal so I'm building a Wine Coolerdor as the summer heat is coming. I'm wondering about the RH% and how low it dips during the cooling phase. I have an EdgeStar 28 Bottle Thermoelectric Wine Cooler (model TWR281S) and I hooked it up to a Temp Controller set with a 69F set point and 4 degree cooling zone to keep everything at 69-65 F. I have 2 pounds of Viper's 65% beads working hard to keep RH where it should be but I'm seeing big dips in RH during the cooling cycle and wonder if that is normal? Here is a chart of min by min Temp and RH% through a whole cycle:

TIME RH% TEMP
0:00 70% 69.0 Start Cycle
0:01 70% 68.9 Start Cooling
0:02 70% 68.7
0:03 70% 68.7
0:04 69% 68.7
0:05 69% 68.7
0:06 68% 68.5
0:07 69% 68.5
0:08 66% 68.4
0:09 65% 68.4
0:10 65% 68.2
0:11 64% 68.4
0:12 64% 68.4
0:13 63% 68.2
0:14 62% 68.2
0:15 62% 68.2
0:16 61% 67.8
0:17 61% 67.8
0:18 60% 67.6
0:19 60% 67.6
0:20 60% 67.5
0:21 59% 67.5
0:22 59% 67.3
0:23 59% 67.3
0:24 58% 67.1
0:25 58% 67.1
0:26 57% 66.9
0:27 57% 66.9
0:28 57% 66.9
0:29 56% 66.7
0:30 56% 66.7
0:31 56% 66.9
0:32 56% 66.9
0:33 57% 66.9
0:34 57% 66.9
0:35 57% 66.9
0:36 56% 66.7
0:37 56% 66.6
0:38 55% 66.6
0:39 55% 66.4
0:40 56% 66.4
0:41 56% 66.4
0:42 55% 66.4
0:43 55% 66.2
0:44 55% 66.2
0:45 55% 66.2
0:46 55% 66.0
0:47 55% 66.0
0:48 55% 66.0
0:49 55% 66.0
0:50 55% 65.8
0:51 55% 66.0
0:52 55% 66.0
0:53 54% 66.2
0:54 54% 66.0
0:55 55% 66.0
0:56 55% 65.8
0:57 54% 65.7
0:58 54% 65.7
0:59 54% 65.7
1:00 54% 65.5
1:01 54% 65.5
1:02 54% 65.5
1:03 54% 65.5
1:04 54% 65.3 End Cooling
1:05 54% 65.5
1:06 55% 65.7
1:07 56% 65.7
1:08 58% 65.8
1:09 58% 65.8
1:10 59% 66.0
1:11 59% 66.0
1:12 59% 66.2
1:13 59% 66.2
1:14 60% 66.2
1:15 60% 66.2
1:16 60% 66.4
1:17 61% 66.4
1:18 62% 66.4
1:19 62% 66.4
1:20 63% 66.6
1:21 63% 66.6
1:22 63% 66.6
1:23 64% 66.6
1:24 64% 66.7
1:25 64% 66.7
1:26 64% 66.7
1:27 64% 66.7
1:28 65% 66.9
1:29 65% 66.9
1:30 65% 66.9
1:31 65% 66.9
1:32 66% 67.1
1:33 66% 67.1
1:34 66% 67.1
1:35 67% 67.3
1:36 67% 67.3
1:37 67% 67.3
1:38 67% 67.3
1:39 67% 67.3
1:40 67% 67.5
1:41 67% 67.5
1:42 67% 67.5
1:43 67% 67.5
1:44 67% 67.5
1:45 67% 67.6
1:46 67% 67.6
1:47 67% 67.6
1:48 68% 67.6
1:49 68% 67.6
1:50 69% 67.8
1:51 69% 67.8
1:52 69% 68.0
1:53 68% 68.0
1:54 68% 68.0
1:55 68% 68.0
1:56 68% 68.0
1:57 68% 68.0
1:58 68% 68.0
1:59 68% 68.2
2:00 68% 68.2
2:01 68% 68.2
2:02 68% 68.2
2:03 68% 68.2
2:04 68% 68.4
2:05 68% 68.4
2:06 68% 68.4
2:07 68% 68.4
2:08 68% 68.4
2:09 68% 68.4
2:10 68% 68.4
2:11 69% 68.5
2:12 69% 68.5
2:13 69% 68.5
2:14 69% 68.5
2:15 69% 68.7
2:16 69% 68.7
2:17 69% 68.7
2:18 69% 68.7
2:19 69% 68.7
2:20 69% 68.7
2:21 69% 68.7
2:22 69% 68.9
2:23 69% 68.9
2:24 70% 69.0 End Of Cycle

Average 64% 67.2
High 70% 69.0
Low 54% 65.3


I'm happy with the Average RH% but don't like the dips down to 54%... Is this normal? I know that I will see some dip during the cooling phase but I was not expecting the dips to be this low.

[indy]

Can you tighten up the cooling temp range a bit? Mine keeps temp at 64.8-65.5 and my RH is always between 62-65%. Mine is a 12 bottle size, so it is a lot smaller.

[WTF Over]

Ok... I'll give that a try... I'll move to a 2 degree range set at 67 F covering 65-67 F and see how that effects this.

[Ringbill]

This is a good chance for someone to educate me. Given that it's 'relative' humidity, wouldn't the ambient humidity be staying the same but relative to the temperature it decreases with decreasing temp? Thus, the beads can't give off enough moisture to compensate in such a short period of time?

I could be way off on this but I guess that's what I was thinking. It would seem that reducing the range as suggested would also reduce the variation in RH.

Good luck!

Josh

[WTF Over]

Josh,

Good Question! It is all FM (Fuck'n Magic) to me so far. I'm ready to test the change right now and will plot a new set of points over the next cycle in the next couple of hours but I too was wondering if the fact that SoCal has an Ambient RH% of high 30%'s to low 40%'s right now and the sizable change in RH% during the first degree of cooling I'm wondering if I'll see better or worse Average RH% with the 2 degree 67-65 degree window. Will post as soon as I have a new plot. Anyone else in SoCal (or somwhere with Temps around 78F and RH around 42%) have some info?

[WTF Over]

New plots:

TIME RH% TEMP
0:01 67% 66.9 Start Cycle
0:02 66% 66.9 Start Cooling
0:03 62% 66.2
0:04 62% 66.2
0:05 62% 66.2
0:06 61% 66.0
0:07 61% 66.0
0:08 60% 65.8
0:09 60% 65.7
0:10 60% 65.7
0:11 59% 65.5
0:12 59% 65.5
0:13 58% 65.5
0:14 58% 65.5
0:15 58% 65.5
0:16 58% 65.5
0:17 58% 65.3
0:18 57% 65.3
0:19 57% 65.1
0:20 57% 65.1
0:21 57% 65.3
0:22 57% 65.3
0:23 56% 65.3
0:24 56% 65.3
0:25 56% 65.3
0:26 56% 65.3
0:27 56% 65.1
0:28 56% 64.9
0:29 56% 64.9
0:30 56% 64.9
0:31 56% 64.8
0:32 56% 64.8
0:33 56% 64.8
0:34 56% 64.8
0:35 56% 64.8
0:36 56% 64.8
0:37 56% 64.6
0:38 56% 64.6
0:39 56% 64.6
0:40 56% 64.6
0:41 55% 64.6
0:42 55% 64.8
0:43 55% 64.8
0:44 55% 64.8
0:45 55% 64.8
0:46 55% 64.6
0:47 55% 64.6
0:48 55% 64.8 End Cooling
0:49 57% 64.8
0:50 57% 64.8
0:51 58% 64.9
0:52 58% 64.9
0:53 59% 64.9
0:54 59% 65.1
0:55 60% 65.1
0:56 61% 65.3
0:57 61% 65.3
0:58 62% 65.3
0:59 62% 65.5
1:00 62% 65.5
1:01 63% 65.5
1:02 63% 65.7
1:03 63% 65.7
1:04 63% 65.7
1:05 63% 65.7
1:06 63% 65.7
1:07 64% 66.0
1:08 64% 66.0
1:09 65% 66.0
1:10 65% 66.0
1:11 64% 66.2
1:12 65% 66.2
1:13 65% 66.2
1:14 65% 66.5
1:15 66% 66.5
1:16 66% 66.7
1:17 66% 66.7
1:18 66% 66.9
1:19 65% 66.9 Start Cooling - End Cycle

Average 60% 65.4
High 67% 66.9
Low 55% 64.6
Ambient 43% 80.7

Well the change cut an hour off the cycle but this caused the Average RH% to drop 4% and the Temp to drop 2 degrees F... I'm thinking that the original setting might not have been that bad... Given the choice between these two options the 4 degree swing might offer a better overall long term storage option as far as a better and slower RH swing. Anyone have any info or suggestions?

[jwrussell]

OK, I'll throw some comments out. First, are those times in minute??? I always thought that TE coolers were supposed to eliminate these swings. The reason I ask about the times is that I have a 32 bottle compressor unit and it takes maybe 15 minutes to go through that whole cycle. So if it's really taking over an hour to cycle through...wow. My initial impulse was to tell you not to worry at all, it really isn't going to matter, but that was assuming we weren't talking about over an hour for the cycle. I mean damn, 48 minutes to cool two degrees?

Next question, is the cooler empty? If so, that's probably a BIG part of the issue. The beads can only react so fast. Part of the buffer that keeps the swings down is always going to be the boxes of cigars and cigars inside the cooler. I can tell you right now that my cooler is a hell of alot more stable when full than when not.

RH is going to fluctuate no matter what you do. It's the nature of RH when dealing with an environment where the temperatures are going to be in flux at different times. The beads can only react so fast, hence, swings. Not really much to worry about most times, but if the times are indeed in minutes then that might change my thoughts just a bit.

[WTF Over]

Yes... those are minute by minute readings in both plots.

Original full cycle was 2 hours 24 minutes for a 4 degree swing, 1 hour 19 minutes when set on a 2 degree swing.

I too thought that using a TE cooler would reduce these swings. I expected some swing in RH% but this was more then I expected.

The cooler is full (or at least not empty). I have about 250 sticks in it and about twenty-four 3/4" X 3/4" X 12" Spanish Cedar sticks for "flavor" and to assist in buffering RH% (or at least I thought they would help buffer RH%)

I see you are in FL so I assume that while you might have Ambient Temps in the same range as SoCal your Ambient RH% is most likely a bit higher.

[CheapBastid]

The issue you're seeing is due to the fact that relative to the surface area in the cooler the TE plate is really small and for it to bring down the ambient temp in the box it has to get significantly colder. When this happens condensation occurs and pulls moisture out of the air.

I've said it before and I'll say it again. I'd gladly pay top dollar for an intelligently designed temperature controlled cooler with three walls and the roofs made up entirely of TE plates that can regulate the temperature more gently. If the TE plates are controlled so that theyt becomes a max of 5° cooler than ambient until ambient comes down to the desired temp in the box the condensation problem dissapears.

[WTF Over]

Makes sense... I was hoping that the RH% swing would be less in a TE unit... Based on the performance to date I guess that it might not make much diff if I used TE or a compressor unit.

While your (CheapBastid) idea for a slower cooling to reduce condensation would be great for us... I doubt we will see a vendor implement it.