1 00:00:00,160 --> 00:00:05,200 Hi, you've made it to the Connextras video  where I explain what the heck is going on with   2 00:00:05,200 --> 00:00:10,720 these wires and all the stuff that I did with  this uh dehumidifier here. If you got here without   3 00:00:10,720 --> 00:00:15,520 seeing the main channel video, there's a clicky  thing. This is to explain an experiment that   4 00:00:15,520 --> 00:00:20,560 I ran on this thing uh and why it didn't work.  Well, I actually don't know why it didn't work,   5 00:00:20,560 --> 00:00:26,880 but my idea did not pan out. So to give you  a quick recap of what that video is about,   6 00:00:26,880 --> 00:00:32,720 that way you don't have to watch the whole thing  if you don't want to. This is a rotary desicant   7 00:00:32,720 --> 00:00:38,400 dehumidifier. And the cliffnotes version of how  it works is this rotate - this wheel of silica   8 00:00:38,400 --> 00:00:45,600 gel rotates very slowly. Air is drawn through the  whole wheel except for this beige section here. The   9 00:00:45,600 --> 00:00:52,240 beige section has a heating element which is getting  the wheel very hot so it releases the moisture.   10 00:00:52,240 --> 00:00:58,640 Uh, and then that hot damp air goes through this  heat exchanger where it condenses into liquid and   11 00:00:58,640 --> 00:01:06,160 goes into a bucket. It's a clever idea, but it's  not very energy efficient. And I had this question   12 00:01:06,160 --> 00:01:14,640 in my head, which was "is this actually an  optimal amount of time for the silica gel to be uh   13 00:01:14,640 --> 00:01:21,920 charging versus regenerating?" The wheel rotates at  about one half of an RPM. It takes almost exactly 2   14 00:01:21,920 --> 00:01:28,160 minutes for it to rotate, which means it's exposed  to the room air for about 80 seconds and then it's   15 00:01:28,160 --> 00:01:36,080 recharged for about 40 seconds. And I was just not  entirely convinced that that was optimal. I had   16 00:01:36,080 --> 00:01:43,120 no idea how much, you know, moisture the silica  gel could reasonably be expected to adsorb in 80   17 00:01:43,120 --> 00:01:50,880 seconds, but I just wasn't convinced that that  was enough time. So, I got my uh you remember   18 00:01:50,880 --> 00:01:56,320 you may remember these temperature controllers  from the space heater... well not the space heater   19 00:01:56,320 --> 00:02:03,680 video the HVAC system sizing video and these  happen to have a duty cycle control mode. So,   20 00:02:03,680 --> 00:02:10,880 I set one of these up to run for 4 minutes on  and then four minutes off. And I disconnected   21 00:02:10,880 --> 00:02:16,560 the wires from the heating element and the blower  motor that actually pushes air through here. And   22 00:02:16,560 --> 00:02:22,000 I'll explain my reasoning there. And I wired them  to a plug and plugged it into this. So, first I   23 00:02:22,000 --> 00:02:29,280 just did a preliminary test where I had it exactly  as you see it now, completely out of its case, but   24 00:02:29,280 --> 00:02:35,280 powered on and operating. It didn't seem to care  that I had disconnected the heater and the blower   25 00:02:35,280 --> 00:02:41,440 motor. It was working fine. Uh, and so this 12volt  fan was running, pulling air this way, but it was   26 00:02:41,440 --> 00:02:47,280 completely out of its case. And uh that meant the  airflow situation was not normal and there would   27 00:02:47,280 --> 00:02:53,680 be very little air flow to cool off the straw  radiator thing. So I literally just put a paint   28 00:02:53,680 --> 00:03:03,040 can here with a tiny little desk fan blowing at  this and um let it run for two hours as normal. In   29 00:03:03,040 --> 00:03:09,280 that time, it extracted 60 grams of water, which  was nowhere near what it can normally do. But that   30 00:03:09,280 --> 00:03:14,720 made sense because again, it's completely sitting  out like this. That's... so of course it's going to   31 00:03:14,720 --> 00:03:21,600 be a different number. So then I unplugged the uh  heating element thing from the wall and plugged   32 00:03:21,600 --> 00:03:26,640 it into my duty cycle controller, which turned  it on for 4 minutes and then turned it off for   33 00:03:26,640 --> 00:03:32,240 4 minutes. And my thinking was that's going to  make sure the desiccant wheel actually gets four   34 00:03:32,240 --> 00:03:38,640 minutes of exposure to the air before it starts  regenerating and then it will have four minutes   35 00:03:38,640 --> 00:03:46,640 of operation as this thing typically operates. And  I killed the blower motor on purpose thinking that   36 00:03:46,640 --> 00:03:54,000 um I would want to completely shut - like I would  want to stop the flow of hot air as quickly as   37 00:03:54,000 --> 00:04:00,080 possible and if this was continuing to go on  then the moisture that was in these tubes would   38 00:04:00,080 --> 00:04:04,720 potentially just get reabsorbed onto the desicant  as it was moving through. So it felt like it made   39 00:04:04,720 --> 00:04:12,240 sense to turn off both the heating element and  the little blower here. And surprise surprise,   40 00:04:12,240 --> 00:04:18,960 despite the fact that I had cut the power draw in  half by turning the heating element, by running   41 00:04:18,960 --> 00:04:28,240 it at a 50% duty cycle, it extracted 70 grams  of water. So, it got more water out of the air   42 00:04:28,240 --> 00:04:35,120 with half power. And my mind at first was like,  "Eureka! This thing is put together poorly. Why   43 00:04:35,120 --> 00:04:41,200 didn't they design it differently?" But because my  brain understands the fundamentals of science, I   44 00:04:41,200 --> 00:04:48,080 changed way more than just one variable. So before  I concluded that that actually meant anything,   45 00:04:48,080 --> 00:04:55,920 I needed to somehow get this back in its case  and do the experiment again. And that I actually   46 00:04:55,920 --> 00:05:01,280 filmed. The first one I I just took pictures of  the water readings, I think. Um and I actually   47 00:05:01,280 --> 00:05:12,080 filmed the setup of the second test. And then,  well, it didn't work. First, the thing broke.   48 00:05:12,080 --> 00:05:20,000 It just wasn't It was suddenly beeping non-stop.  And what that very well might have been, uh, it   49 00:05:20,000 --> 00:05:26,560 has two temperature sensors in the heater circuit  thing um, to determine if it's overheating. And   50 00:05:26,560 --> 00:05:32,000 I thought they might be thermal switches, which  opened. They don't seem to be based on my testing   51 00:05:32,000 --> 00:05:37,920 with a voltmeter. So, I don't know if that's why  it died, but certainly what I was doing by killing   52 00:05:37,920 --> 00:05:42,000 the power to the heating element and the blower  at the same time, things were getting hotter than   53 00:05:42,000 --> 00:05:47,440 they should be. When operating as normal, whenever  you turn this off, it keeps the fans running for   54 00:05:47,440 --> 00:05:54,080 like 30 seconds and then turns off. So, I knew I  was kind of asking for trouble. But regardless,   55 00:05:54,080 --> 00:05:58,320 nothing actually broke. It's just the control  circuitry was was deciding I'm not going to work   56 00:05:58,320 --> 00:06:08,000 for you anymore. So I then had to wire the fan  to these wires here. That way I could run this   57 00:06:08,000 --> 00:06:13,520 in completely manual operation. So I needed  to this wire is going was going to a second   58 00:06:13,520 --> 00:06:21,440 plug. This was going to a DC power supply to  run the fan. And then the plug oops the plug   59 00:06:21,440 --> 00:06:28,320 that I had already wired to here the heating  element and the blower went into this thing.   60 00:06:29,280 --> 00:06:34,000 Well, and the wall originally. So, I repeated  the tests with it fully powered on as normal,   61 00:06:34,000 --> 00:06:41,680 just the control circuitry was not awake for any  of this. And I think uh hold on, I wrote this down   62 00:06:41,680 --> 00:06:46,880 somewhere. So, once it was reassembled with the  wires poking out carefully and having everything   63 00:06:46,880 --> 00:06:57,040 running as it should, it extracted 159 g of water  in 2 hours, which is pretty typical. And then I   64 00:06:57,040 --> 00:07:09,280 plugged the heating element and blower into this  and it extracted 74 grams of water. So it's Yeah,   65 00:07:09,280 --> 00:07:14,160 I was pretty bummed when that happened because  I really thought that I had stumbled upon like   66 00:07:14,160 --> 00:07:20,320 there's something because this thing just runs  the heating element at full power uh in the high   67 00:07:20,320 --> 00:07:28,160 span highspeed mode. High fan speed mode. That's  what I meant. It runs in full the heating element   68 00:07:28,160 --> 00:07:36,000 is just on if you have this in its maximum power  mode and that just didn't seem right. It or it   69 00:07:36,000 --> 00:07:42,880 seemed like that might not be right, but it's  right. So, the experiment was a failure. Um   70 00:07:42,880 --> 00:07:48,960 80 seconds appears to be just as much time as  required for this to uh adsorb as much moisture   71 00:07:48,960 --> 00:07:55,120 as it can hold on to. And you know, in hindsight,  that makes that kind of makes sense. I mean, it's   72 00:07:55,120 --> 00:08:01,920 it's not like this can actually hold on to much  moisture at all. Um, but you're not you never see   73 00:08:01,920 --> 00:08:09,040 it wet. That's not how this works. It's just um  I mean on the molecular level, I couldn't tell I   74 00:08:09,040 --> 00:08:13,680 couldn't tell you what's happening, but molecules  of water are sticking to the silica gel and then   75 00:08:13,680 --> 00:08:21,520 they're being able to pushed out from the other  thing. Um, but the 80 seconds in the airirstream   76 00:08:21,520 --> 00:08:27,040 and then 40 seconds in the hot airirstream  appears to be pretty close to ideal. So,   77 00:08:27,040 --> 00:08:33,840 I have no idea what happened when I tested it the  first time, why it was able to get more moisture,   78 00:08:33,840 --> 00:08:41,449 but um I'm guessing that was just a fluke because  it it it was only a small... 79 00:08:41,449 --> 00:08:49,440 Well, the other thing it could be is um when this is running at half power, it does cut the power to the heating element in   80 00:08:49,440 --> 00:08:54,000 half. I shouldn't I shouldn't say half power.  In the night mode, I think is what it calls it,   81 00:08:54,000 --> 00:08:59,680 the heating the power draw drops to about 150  watts. So, when it slows down the air flow,   82 00:08:59,680 --> 00:09:10,240 it also slows down the heating or it lowers the  heating power. So, I guess effectively because   83 00:09:10,240 --> 00:09:16,640 the air flow was messed up in my situation, I was  doing the same thing with the heating element,   84 00:09:16,640 --> 00:09:25,040 cutting it down to half power, but I was doing it  uh through a duty cycle through timing rather than   85 00:09:25,040 --> 00:09:31,440 actually lowering the power power level if that  makes sense. Um yeah, so this is just kind of a   86 00:09:31,440 --> 00:09:37,200 bit of a rambly quick like what quick explanation  of what I was doing. I I I had started to write   87 00:09:37,200 --> 00:09:42,000 I had a section in the script where I explained  this experiment, but then I realized this doesn't   88 00:09:42,000 --> 00:09:46,640 it doesn't do anything. It was just me making it  was just an excuse to make fun of the people who   89 00:09:46,640 --> 00:09:54,284 put this together, but they did nothing wrong.  So, yep. That's all there is to this video. 90 00:09:54,284 --> 00:09:54,784 Bye!