WEBVTT Kind: captions Language: en 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   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   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   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,   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,   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   00:00:32.720 --> 00:00:38.400 dehumidifier. And the cliffnotes version of how  it works is this rotate - this wheel of silica   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   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.   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   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   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   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   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   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   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   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   00:01:50.880 --> 00:01:56.320 you may remember these temperature controllers  from the space heater... well not the space heater   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,   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   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   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   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   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   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   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   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   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   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   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   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   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   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   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   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   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   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   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   00:04:04.720 --> 00:04:12.240 sense to turn off both the heating element and  the little blower here. And surprise surprise,   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   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   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   00:04:35.120 --> 00:04:41.200 didn't they design it differently?" But because my  brain understands the fundamentals of science, I   00:04:41.200 --> 00:04:48.080 changed way more than just one variable. So before  I concluded that that actually meant anything,   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   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   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.   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   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   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   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   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   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   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,   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   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   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   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   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.   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,   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   00:06:41.680 --> 00:06:46.880 somewhere. So, once it was reassembled with the  wires poking out carefully and having everything   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   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,   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   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   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   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   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   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   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   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   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   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   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   00:08:21.520 --> 00:08:27.040 and then 40 seconds in the hot airirstream  appears to be pretty close to ideal. So,   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,   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... 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   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,   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,   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   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,   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   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   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   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   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   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. 00:09:54.284 --> 00:09:54.784 Bye!