Build a performant DIY portable air conditioner (ICE POWERED) - Page 1
Forum section: electronics / projects

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 21, 2024, 12:46:03 am
content: Hello to all,this sound like a stupid question, but I'm stuck on this from several days and I had no other chance than ask for help.I want to buythis100mm Dryer flexible Vent Hose and I need to connect to my4 inches (102mm) SEAFLOW blower fan:As you can see the diameter of my fan is 2mm more than the vent hose diameter and to complicate things, there is some sort of 10mm thread which probably expand diameter to 105mm (there is a label with printedINTAKE: 4" (105mm)).This is how the same fan should look once connected (taken from an existing project I'm using as inspiration):Hereis where the 4" duct flex in the above sample has been purchased. I can't find any details or diagrams in the product link, but description clearly states that diameter is 4 inches (102mm).My main concern is that the duct I want to buy is 100mm and not 102mm.I never had chances to play with flexible Vent Hoses and I'm wondering if their diameter can be stretched to connect to a pipe of about a couple of mm more larger diameter. From the sample seems possible (otherwise it wouldn't connect to a 105mm intake), but the duct I want to buy is from a different brand and I'm not sure it has the same expansion capacity (mine is 4-layer thickness while that one 3-layer thickness and the 2 missing millimetres in diameter increase my concerns).Many thanksEdit:This thread evolved with many useful information and ideas. So I changed the title from "I need to connect a 100mm Dryer flexible Vent Hose to a 102mm pipe" into "Build a performant DIY portable air conditioner"Below is a (not definitive) diagram that shows how should be. The processing unit is detachable meaning that the ice chest can also be used as originally was designed for (ex: picnics).WARNING! IF YOU ARE GOING TO FREEZE THE ICE PACKS THROUGH A FREEZER AND THE FREEZER IS LOCATED IN THE SAME ROOM YOU WANT TO COOL, THIS DIY PORTABLE AIR CONDITIONER WILL NOT WORK.More detailshere. Many thanks toIanBfor this and many other contributions to the thread!

author: IanB
author_rank: Super Contributor
timestamp: July 21, 2024, 01:29:08 am
content: I would guess it may not fit. You would prefer a flexible hose with a 4 inch (102 mm) inside diameter.The hose you linked to is made of thermoplastic material (good for stretching), but it is lined with aluminum foil and steel wire reinforcement (not stretchy).If the hose was only made from plastic you could likely warm it up with a heat gun and stretch it over the fan connection. However, with aluminum and steel wire in the construction I don't know if it would stretch so well. It seems like a gamble.

author: rich t
author_rank: Contributor
timestamp: July 21, 2024, 01:44:22 am
content: The steel wire is a spiral...So if you can twist the hose a bit, you can make it (a bit) larger or smaller, depending on if you twist with (smaller) or against (larger) the spiral...The hose also gets wider if you unstretch it -- i.e., compress all the spiral rounds together -- its nominal diameter is when it is nominally stretched -- it naturally gets to be a larger diameter when unstretched/compressed.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2024, 02:40:13 am
content: Tolerances on flex ducts are quite loose, 2% isn't going to be a problem.

author: Dundarave
author_rank: Regular Contributor
timestamp: July 21, 2024, 02:46:17 am
content: Try googling “dryer duct connector” and your location. There might be an available solution that will either solve the issue, or provide you with the parts to cobble up a solid solution.

author: themadhippy
author_rank: Super Contributor
timestamp: July 21, 2024, 03:22:56 am
content: Been there many times,some its a right battle,others just fall on.The method ive found best is to stand the fan up on a solid surface,compress the pipe as much as possible and stretch it down whilst twisting it onto the fan boss

author: Psi
author_rank: Super Contributor
timestamp: July 21, 2024, 04:04:11 am
content: I've 3D printed adaptors for fan/air ducting before, worked well.Used one to get my floor mount solder fume extractor outputs to fit onto the extractor tubes running to the desk.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: July 21, 2024, 06:21:54 pm
content: Good Morning Psi, I've heard that flexible dryer vent pipe is horrible, since there is not a 'smooth' flow of drier exhaust, and they get filled up with lint and are very difficult to clean out. Try to get some solid vent pipe, (mine is 4"aluminum).It also would be easier to fasten to your booster.

author: mr ed
author_rank: Regular Contributor
timestamp: July 21, 2024, 11:13:47 pm
content: Dryer duct should be metal, not any plastic. Plastic is a fire hazard, more so with lint.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 21, 2024, 11:27:41 pm
content: Aren't vented electric dryers obsolete? All the high efficiency dryers I see nowadays are ventless heat pump.I don't think this is for a dryer, but something else that needs venting.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 23, 2024, 07:28:26 am
content: Many thanks to all for the numerous responses and sorry for my delay, but I wanted to wait for the seller response. He told me that it can be stretched to 102mm. However I made him aware that with the intake becomes 105mm. He'll manually check stretchability directly in the warehouse and will let me know.Quote from: IanB on July 21, 2024, 01:29:08 amMost of the flexible hose are 4 inch in size and I'm surprised this one has such strange diameter. I have chosen this one because seems to be of the best quality (4 layer Thickness).I'm not sure about each layer thickness, but in theory, If I can remove one or more layers I should be fine.By looking atsimilar productsit seems possible and steel wire is around 1mm:Thanks for heat gun tip, this should be of great help when dealing with very little tolerance.Quote from: rich t on July 21, 2024, 01:44:22 amMany thanks. I think that the photo above should represent the result after your technique applied.Quote from: NiHaoMike on July 21, 2024, 02:40:13 amWith the intake becomes 5%, but I hope I can remove the layers or, even better, the technique suggested from rich t.Quote from: Dundarave on July 21, 2024, 02:46:17 amYes, that was what I tried when I saw this potential problem. On AE I didn't found anything about "100mm to 102mm" and elsewhere I found the opposite. However there are very cheap joiners which are 100mm on both the sides and given that the internal dimensions of the fan is exactly 100mm, I could do the connection as is directly from within the inside. Maybe some hot glue to seal it well.Quote from: themadhippy on July 21, 2024, 03:22:56 amThanks for the precious information. In fact I was having no idea on how would have been the best way to attach the hose without breaking it.Quote from: Psi on July 21, 2024, 04:04:11 amA 3D printer! This is for sure something that soon or later I will have to add to my arsenal!Quote from: BILLPOD on July 21, 2024, 06:21:54 pmI'm surprised about this and I really need to check better before I buy.This is a portable DIY air conditioner. What the fan does is suck cold air from a radiator placed inside a container. it is partially based ondesign. I'm not sure on what could be better for this kind of applications, but all the projects I saw uses flexible dryer vent pipe.In this specific application, keeping the air cold and a very low noise is important, so I'm not sure if a solid aluminium vent pipe is suitable. What you think?I'm not sure if there is the risk of lint, but the length of the hose is 5 meters. If cleaning becomes harder I can just replace with a new cut.The not 'smooth' flow you're talking about is for sure a concern. Do you mean this translate in a reduced range of blowed air?Quote from: mr ed on July 21, 2024, 11:13:47 pmI'm not sure if there are such risks in my specific application. Every device in my home is made of plastic just like the portable conditioner I'm building. Probably you're talking about fireplaces or fume extractor in the kitchens.What aboutsilicone tubesused for intercoolers?Quote from: NiHaoMike on July 21, 2024, 11:27:41 pmYes, this is not for a dryer. I'm building a. I don't think ventless heat pump can be of any help in this kind of project.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 23, 2024, 08:04:50 am
content: Guys, I see that you're all very experienced about blower fans. Unfortunately the connection with the hose is not the only one problem I'm facing.I want to regulate speed based on the detected ambient temperature, but this fan is only 2 wires while the controllers are designed for 3-4 wires PWM fans.If you want to help me, I have an open thread on this and no one has been able to help me (link).I hope to complete this project as soon as possible (here is nearly 35C°) and before september (when will be useless).Thanks

author: DTJ
author_rank: Super Contributor
timestamp: July 23, 2024, 01:50:40 pm
content: Grab a short 50mm long bit of 100mm or close to DWV (drain waste vent) or storm water pipe. Make a cut in the wall and insert it into the end of the fan housing. Glue it in place. It will provide a smaller OD to slip your vent pipe onto.

author: zapta
author_rank: Super Contributor
timestamp: July 23, 2024, 03:18:31 pm
content: If you don't have access to a 3D printer, you can use an online service such as thishttps://jlc3dp.com/3d-printing-quote

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 23, 2024, 08:02:57 pm
content: The seller responded to me and said that it cannot be stretched. I really appreciate his honesty. No further info, but I suppose unstretchability is due to steel and aluminum layers.Quote from: zapta on July 23, 2024, 03:18:31 pmI'm afraid between the cost of the service, shipping costs, time to edit the project etc it doesn't worth, but thanks anyway.Quote from: DTJ on July 23, 2024, 01:50:40 pmI've not been able to find any DWV or storm water pipe in AE. May be I used the wrong search terms? Perhaps some sort of very hard rubber? This one should be easy to find (edit:no, not easy to find at all).Quote from: DTJ on July 23, 2024, 01:50:40 pmNot sure if I've understood well, but I suppose the cut to the wall is to facilitate the hookup into the internal 100mm diameter of the fan. I like your idea, but does not seems easy to find such product with the required diameter. The closest I have been able to find isthisplastic joiner:The valve should be easy removable, butthere is inside a ring that slows down the air flux. Also, with a solution like that, the internal diameter of the fan will be reduced.I still hope for a solution that works externally and leave the internal working area free.This is an approach that I would prefer to stick as the last resort. I still hope I can remove the offending layers and directly plug the hose like in the linked youtube video.BILLPOD has done some good observationsabout the cons of flexible vent hoses. Not sure how many points apply in my specific case, but the absence of a 'smooth' flow for sure.I'm trying to understand ifsilicone tubes used for intercoolers like the one I posted above perform better for noise reduction, temperature insulation and air flow. They are alsoavailable with 102mm IDand from what I see they aremuch easier to fasten. Someone expert may want to tell mewhat could be the downsides.There must be a reason if all of the portable DIY conditioners I had chance to check only use such flexible vent hoses.

author: kripton2035
author_rank: Super Contributor
timestamp: July 23, 2024, 08:16:46 pm
content: this :https://www.thingiverse.com/thing:1950864and a good large enough 3d printer and you can make all the adaptors you need.

author: IanB
author_rank: Super Contributor
timestamp: July 23, 2024, 09:49:50 pm
content: Quote from: YouCanDoIt on July 23, 2024, 08:02:57 pmActually, this sort of thing you would find in a local hardware store.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 23, 2024, 10:03:19 pm
content: Quote from: kripton2035 on July 23, 2024, 08:16:46 pmQuote from: IanB on July 23, 2024, 09:49:50 pmThanks guys, but I think I will go with the silicon hose I posted above. It doesn't need any adapter and I have reasons to believe that perform much better than a flexible hose. I just want to see what people have to say and if this could be the best solution for my specific project.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 25, 2024, 08:03:44 pm
content: Guys, I think that people reading this thread will end up with wrong informations (especially from side).It has been said that solid ducts are better than flexible ones, but this not applies to all applications especially mine.I was going to do the mistake to buy a silicone hose:The main disadvantage is that, unlike flexible hoses, there is no noise reduction and this make them unsuitable for applications like mine (and explains why I see no design using solid ducts). And there is no way to reduce noise in a solid duct.There is a discussion aboutFlex vs Solidand below I quote some of the most interesting statements:QuoteI've also been told that with a flexible hose I am free to decide the exhaust length and the more is the length, the more is noise reduction.I resume here some good points raised from users about flexible hoes for which I don't see any concern:Quote from: mr ed on July 21, 2024, 11:13:47 pmIt depends from the application. In a portable conditioner there is no fire hazard risk. For other application (kitchen fumes extractors etc) most of the flexible hoses in the market (included the one in this thread) are flame resistant.Quote from: BILLPOD on July 21, 2024, 06:21:54 pmThe lack of 'smooth' flow is what probably contribute to noise reduction. In the youtube sample I posted there are no issues in that matter. if there are applications that need to deal with lint, I would say it would be much easier to just replace with a new cut (flex hoses available in the market are normally several meters in length).Fastening is easy just like flexible ones, mine is just a rare case of unmatching diameter.So, unless someone has valid reasons for using a solid hose for this specific case, I'm going to buy the flexible one and the same may want to do users that work with systems that have the same requirements.

author: IanB
author_rank: Super Contributor
timestamp: July 25, 2024, 09:03:51 pm
content: You will find that ducting is a bit like wiring. Rigid ducts tend to be used for fixed installations with mounting brackets, and often inside walls or ceiling voids. Flexible ducts are typically used to cross open spaces, where some movement may need to be accommodated, and where it is not a fixed installation.As far as the noise is concerned, noise levels depend heavily on the flow velocity. With low flow velocities the noise may just be a whisper.Another consideration is that flexible hose might have a higher pressure drop due to the lack of smoothness on the inside. So flexible hose would be more suitable for short runs rather than longer runs.There are so many variables that you will have to decide based on your knowledge of the details.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 29, 2024, 05:06:29 pm
content: Quote from: IanB on July 25, 2024, 09:03:51 pmMany thanks for your response. It contains very useful tips that help to identify the more suitable duct for specific conditions.Based on your tips, to me the flexible one seems to be the more appropriate:Noise level: it's a 270CFM blower fan, so I think velocity is pretty high. From the video the noise does not seem too much, but it's still a boring noise.The right side connection is short and fixed. The left side longer and flexibility is needed to output air to the desired direction (not sure why it has been used a pipe reducer adaptor, may be to create more pressure and get a longer range)Honestly I'm still tempted from the silicon one. It has the same diameter of the fan and don't need any adapter, but I'm still concerned about noise and thermal insulation (I feel like the flexible one can isolate cold air flux better from heat).What you would choose if you were me?

author: IanB
author_rank: Super Contributor
timestamp: July 29, 2024, 06:02:43 pm
content: Based on the video, thermal insulation is a non-issue. The goal is to cool the surrounding area, so you want the cold to escape. That is the whole point of a cooling device.The majority of any noise is going to come from the fan/blower unit. The ducting has little to do with it, especially with the short lengths in the video. (The noise comes from the motor and the whirring blades of the fan. For less noise, you need bigger, slower moving fan blades.)Based on the video images, I would go with flexible stuff similar to what was shown there. If only because it will be easier to work with.That said, it is not the design I would build. I would mount (something like) a car radiator on top of the ice box, and would pump the cold water through that. I would then place a normal room fan to blow (or pull) air through the radiator. The room fan will be quieter, and will give a softer, more gentle breeze of cool air. Perhaps use a box fan to pull air through (fans are generally better at pulling than pushing).(Search for "box fan" to see what I mean. They are big, square fans that could be mounted up against a radiator of similar size and shape.)

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: July 30, 2024, 10:46:21 pm
content: IanB, you really know what you're talking about!Quote from: IanB on July 29, 2024, 06:02:43 pmYes, it seems to come from the motor itself.I have read the same tips under the comments of this other design:Here noise seems much more noticeable (same ice chest and radiator), but I'm not sure if it is due to a smaller blower (3" 130CFM) and/or the duct made of just one aluminium layer. So, I preferred a 4" 270CFM blower + 4 layer flexible duct combo. The guy that made the build stated that a longer exit tube also contribute to noise reduction. The flexible duct is 5 meters long and can be cut into pieces.Quote from: IanB on July 29, 2024, 06:02:43 pmWell, the black silicone solid duct shown above should fit as is because diameter is exactly 102mm, just like the fan. The flexible duct is 100mm and probably I will have to use some adapter if there is not enough tolerance. However, a solid one needs the fan kept at a specific height point, so I will end up with some adaptor anyway. The flexible hose goes straight into the blower intake, so probably it will not make difference whether it is solid or not. Probably I'm better off with a flexible one since I can also get from it a second cut for a directional exit tube which, at least from what said the guy, can help to reduce noise. If there is some noise coming from the hose (which we cannot detect just by looking a video), it will be impossible to fix when the hose is solid.I'm in doubt about the exit tube on the video. Except the ability to change flow direction, I'm not sure if there are other benefits or even drawbacks when diameter is reduced in such a way. Perhaps a smaller diameter create more pressure resulting in a longer range, but to me that seems only useful for outdoor use to target the specific area where people are located. In this case a longer range could ensure the whole area is constantly cooled. On a closed room the cold is going to expand anyway.Quote from: IanB on July 29, 2024, 06:02:43 pmI'm very glad to see that I am not the only one that thought the same. In fact my design is very similar to what you described, but given that I saw no implementation anywhere I asked myself if would have been a mistake.This is the8 rows car radiatorI have already purchased:There are basically two containers. The first one is a 52QT rotomolded ice chest (advertised ice retention is 6 days) and its main purpose is to keep water cooled through gel ice packs (which seem to last much longer than regular ice packs). On top of it a second (and much smaller) styrofoam box where all the work is done. Inside of it the radiator and the water pump (blower fan is attached on the top). The containers are connected through two small 10mm holes corresponding to the inlet and outlet of the radiator. In this way the heat has no chance to penetrate. It also allows me to detach the top container and use the ice chest box as originally was designed for.I thought to the box fan, but I've read is bad design because generates heat. On a room does not make much difference, but on a small container the heat easily accumulate. Yes, it is much quieter and with a one big enough to cover a radiator like mine the noise could be even unnoticeable. However this means a much less output. From what I have understood, this is more intended as a fan that emits gentle breeze of cool air, but it will not work to decrease room temperature like does a regular air conditioner.Anyway, given that my design is made of two separate containers, I asked myself if adding an helper box fan can help. As you see the blower fan will only be able to target a small area of the radiator. I will keep the radiator attached to the top wall through a gasket (probably made of styrofoam) in order to create more pressure and suck from a larger area, but I'm still wondering if a secondary box fan pushing air against the radiator can help. This is probably something I should evaluate later once I see how much is large the area covered by the blower.Pheraps I should try to keep the container as small as possible not only for general space saving, but mainly because I assume the smaller is the container the more pressure is generated resulting in a larger sucked area from the radiator. Is this correct?Last thing...the linked youtube project is the only one that uses two air intake and I suspect because of the very small volume available to the blower after the lid insulation. In my case I suppose I should also try to reduce volume as more as possible, but the radiator is much larger. Do you recommend one or two air intake?

author: IanB
author_rank: Super Contributor
timestamp: July 30, 2024, 11:21:29 pm
content: My idea is not to put the radiator inside the ice chest, but rather to stand it upright in the open air on top of the chest. The box fan is then mounted against the radiator, also in the open air. The box fan by itself would just move air through the room, like any room fan. When you place the radiator next to the fan, the fan will suck air through the radiator, and will then move the cooled air around the room.The water pump will simply take cold water from the reservoir, pump it through the radiator, and return it to the reservoir.I see very little to be gained by putting the heat exchanger inside the cool box and then sending air through small ducts in and out of the box. The air is in the room, the cold is inside the box. We want to bring the cold out of the box, not send the air into the box.See the video below, and others like it, for inspiration. In that video Matthias is sucking air through a filter, but here we want to suck air through the radiator instead.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 01, 2024, 01:33:12 am
content: Quote from: IanB on July 30, 2024, 11:21:29 pmOh, now I understand. Well, I have considered such design at the beginning, but I ended up with the motor blower one once I saw the limitations (some are just my deductions and I could be wrong):A radiator kept in the open air will absorb the heat from the room resulting in an air flow less cold.Condensation may occur and if severe can block the radiator or the airflow in a noticeable way. I'm not sure if this phenomena has more chance to occur outside or not, but I suppose that when inside a container it will be easier to take over it. With a motor fan, the airflow through the radiator should be stronger and less subject to these issues.Condensation generates water that drops on the floor. Nothing that can't be solved with a basket, but a container is more convenient because also act as a drops collector.It seems that a motor blower is able to generate the coldest air temps, at least said so the same guy above who also built a couple of box fan projects:.Unless I'm missing something, instruments also seems to confirm such statement:I believe that in all of its projects the fan is positioned in the way you described (radiator next to the fan in order to suck air through the radiator). You have to consider that the design in the photo uses a less powerful motor combined with a very cheap small radiator.The issue with a box fan is if you keep it insulated inside a container it still generates lot of heat. You solve this problem if you remove the insulating container like the project above, but at this point the radiator is exposed to the heat of the room and some of the cold is lost in the road. This should have a much bigger impact compared to the heat introduced in a cold container through an air intake.I'm not sure if such designs are able to change a room temperature especially when temps are very high. From what I have understood, they seem more suitable to get some gentle breeze of cool air while sleeping given that they are practically free from noise. I was going to buythis air cooler, but I had to realize that they just don't work and opted to build my own. Of course those are very cheap coolers that have nothing to do with the ones we see here, but the basic design is the same.The same guy posted a video showing that he was able to drop room temperature by 10F from 85F, but he had to use a 16 row radiator combined with a gigantic and powerful 0.5 meter fan. This one really makes lot of noise and what about higher temps like 95F?Quote from: IanB on July 30, 2024, 11:21:29 pmYes, we want to bring the cold out of the box and, most of all, preserve its temp by keeping it far from any heat source (and the radiator should also be kept away from any heat source). This is the main reason for which I designed two separated containers, but I think I have not explained well if you think the small ducts are for sending air.With the regular design (everything processed inside the ice chest box) we have to make 1-2 big holes for air intake, plus another one for the blower. Insulation is totally broken in such a way and we can only partially mitigate the issue because the air has to enter in some way. That's why to me seemed much better to leave the ice chest box totally insulated (apart two small 12mm holes used for the communication).This diagram should give you a better idea (elements are not proportional, but I can only use Paint 3D now):Top container (styrofoam):1 or 2 air intakes + blower motor + water pump + radiator + (perhaps) 1-2 gel ice packs (to reduce heat introduced from the air intake/s)Bottom container (ice chest):gel ice packs submerged in waterThe two containers are connected through the twos pipes you see on the right side. The one to the left push the water exiting from the radiator outlet. The one to the right sucks the cold water which is pushed to the radiator through the water pump inlet. There is no air circulation between the containers, just the water and the whole thing is processed in the same way of the "all-in-one" common designs.The two pipes are connected to the bottom container through quick release pneumatic fittings. This allows me to quickly detach the small container and use the ice chest box as was originally designed for (storage for cold drinks etc).The reasons for which I'm reluctant to remove the top container and leave the related parts exposed are multiple:without the thermal insulation provided by the box, the radiator and all the working parts are exposed to the heatMore complicated work to join all the pieces togetherParts can easily get damaged during transport.I feel that without a container the blower will suck a much smaller area from the radiator due to the lack of pressure (probably no more than the fan diameter)My main concern is the heat introduced by the air intake. This is unavoidable because required by the blower motor. I have read that there are several tricks available to reduce the heat, but I have not yet investigated. Do you have something to recommend?So, now that you should have a clear idea of my design, do you see any flaw?Adding a box fan could be useless. May be that the blower motor itself is enough to get all the available cold from the radiator, but this is something that I will only know in the field.Thanks for the video. It's a bit difficult to get an idea because the project has a completely different purpose and use parts that are unrelated for the kind of project I'm building. However, what I saw is the same I previously talked about: the necessity to use much bigger parts included a gigantic fan in order to make things work.I see so many of such videos before going with the blower motor. Many people that tried both the approaches are against the box fan, but many other people are in favour. It's very hard to understand what is better because there are too many variables and what does not work for someone it could be simply due to some flaws in the design.Blower motor design is what seemed to me to give more chances of success along with easiness construction and more portability, but I could be perfectly wrong on the cooling performance.I'm afraid is too late for me to change design because I have already the fan and I certainly don't want to lose the money I had to spend. Frankly speaking, I'm glad to not have the option to change design because this would mean returning back to beginning when I had to do long and very stressful researches.

author: IanB
author_rank: Super Contributor
timestamp: August 01, 2024, 02:18:19 am
content: You are right about the drawbacks of what I suggested:- possible condensation on the radiator- more cumbersome design- more complicated mechanical constructionHowever, we do not need to worry about the temperature of the cold air (unless you want to sit directly in the draft), and we do not need to worry about heat from the room warming up the radiator. That is what is meant to happen, otherwise the radiator would not be working.It all comes down to an energy balance. The ice and/or cold packs inside the ice chest represent a reservoir of "cold" (= lack of heat). "Cold" can be measured in kJ, just like heat. We can do an energy balance on "cold" flow just like we can do an energy balance on heat flow. This is just the same as considering conventional current flow from positive to negative, or electron flow from negative to positive. Both perspectives lead to the same conclusions.Our goal is to release the store of "cold" into the room at a controlled rate, measured in kJ/h. It doesn't matter if heat from the room warms up the radiator or exposed piping, because this is just "cold" escaping into the room, which is wanted anyway. The outcome is that the rate of cooling of the room is slightly higher than otherwise.Having lower air temperature is not a measure of performance in and of itself. A small flow of colder air has the same cooling effect on a room as a larger flow of less cold air. But a larger flow of colder air will just exhaust the cold reservoir faster, which is fine if it's what you want, but not fine otherwise. It's all about energy balances and rates of change.Where outside heat matters is, as you suggest, any heat dissipated by the fan or the water pump motors. These are indeed bad sources of heat that will reduce the efficiency of the whole setup. So ultimately, you want the most efficient motors possible, which are probably DC brushless motors.And just a note: if there is a box fan, there is no blower motor, and no flexible ducting. That all disappears.But in the end, you should go ahead with the design you have planned if you are already along that path. It has videos where people have built it, and presumably it works as demonstrated.

author: IanB
author_rank: Super Contributor
timestamp: August 01, 2024, 02:55:37 am
content: Just for reference, here is a sketch of the concept I have in mind:

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 01, 2024, 09:47:28 pm
content: Quote from: IanB on August 01, 2024, 02:18:19 amYou demonstrated that what seems to be obvious to the eyes doesn't necessarily match the laws of physics and the energy balance seems to be one of such cases.Please correct me if my following assumptions are still correct:The colder we can make our cold source (the bottom ice chest) the better is. Besides a well designed insulation, the coldness of the output airflow depends mainly from the cold source and the colder is the airflow, the faster are cooling times and this allows better energy balance along with power saving (when target temp is reached we can slow down the process and enter in some sort of "maintenance mode"). The process of making the cold reservoir as cold as possible does not involve special high power consumption devices, but is just a matter of finding the right design. For this I have opted for the gel ice packs since they last longer. I'll only use 1000ml bags (the biggest I could find), but it appears that there are different variants.This discussiontalks about the different characteristics like freezing point, melting point, latent heat, heat capacity etc. This is again physics territory and at some point, instead of losing time in reading lot of papers, I ended up to save in my purchase list some ofthis cheap gel ice packsfor which there aren't even specs (I need my cooler now, not after the summer). You know very well physics, so I would really appreciate if you want to suggest me some particular variant which allows to make the reservoir coldest and long lasting as possible.You said that I do not need to worry about the temperature of the cold air as long as there is the right energy balance and I understand the concept. However, supposing two scenarios, both with the same good energy balance design. The first one has 5 Celsius output airflow while the second one 15 Celsius. The first one will perform better anyway due to the various reasons described in the previous point.Quote from: IanB on August 01, 2024, 02:18:19 amI totally agree on the controlled rate concept and with this is in mind I have on my purchase list a controller board which slow down the fan speed (and the water pump flow) based on the detected temperature. You may want to give a look at thethreadI opened on that matter. The one I found is very limited in capabilities, but is the better I could find with the needed amperage and that works with 2 wire fans. I opened asecond threadbecause I found another much better board, but it only works with 4 wires fans and no one here seems to know how can be adapted to work with my 2 wire fan, so I ended up with the limited model that I know to work (I have not yet done the purchase, so, if you know how I can adapt the 4 wire controller board with my fan I would really appreciate).Thanks for the tip about the two exposed pipes you see in my diagram. Those are the tubes that comes with the radiator and I would say they are already well insulated (16mm external diameter, 9 mm internal diameter). I was going to do the mistake to buy some pipe insulation foam for further insulation!!At this point I'm wondering if I should replace such tubes with smaller and less insulated ones. I have not been able to show such detail in my diagram, but the two holes on the ice chest box lid are not 16mm as you may expect, but 10mm. This because I want to reduce any heat penetration inside the ice chest box. Basically, between the lid and the external pipe there is one "10mm to 16mm reducer adaptor". This means that tube inside the ice chest (and the hole itself) is 10mm which expand to 16mm when outside. Based on what you said I'm afraid this is another flaw and I should just use 10mm tubes everywhere except may be for the left tube (the one that pushes the hot water in the reservoir, we want this well isolated and avoid it to push further heat inside the reservoir).Quote from: IanB on August 01, 2024, 02:18:19 amI totally agree, the air temperature alone is not a measure of performance. There are many variables that comes into the play like the flow size/speed etc. However, at the same flow size, speed etc, a lower temperature still provide better performance since it allows better control on energy saving, cold preservation etc (in combo with a temperature controller I plan to buy, for example).Whether this target should be achieved by optimizing the cold source, the working layer or both, I'm not sure (for this reasons I'm focused on both).The hardest part is the working layer:one air intake? Two air intake? Container dimensions should be reduced? The right gasket size to sucks the most possible largest area from the radiator? Etc etcI think the best I can do is buying a couple of styrofoam boxes and experiment with the different configurations (fortunately they are cheap).Quote from: IanB on August 01, 2024, 02:18:19 amYes, heat dissipated by the fan plays a role in reducing efficiency:Do you have any idea on what could be a workaround? 11F is a noticeable loss!Regarding the pump I was planning to buythis one. It is commonly used in many similar DIY projects and provides inlet and outlet tube connectors for non-submersible install (which I suppose is the best one).Do you see any heat dissipation issues? it's just a couple of dollars and I can invest extra money if you want to recommend some better alternative. This one is already DC brushless.Quote from: IanB on August 01, 2024, 02:18:19 amYou seem to confirm what were my suspects. Combining two different devices like a blower motor and a box fan can result in many adverse side effects during their interaction.If I see that I'm unable to get all the cold from the radiator even with the best configuration, the only think I can do is adding a secondary blower. I can reuse the left hose and probably a cheap motor could be more than enough for what has to be considered as an helper.Many thanks for the sketch, I really appreciate. Except for the box fan is very similar to mine. I placed the water pump outside the cold container to avoid any heat dissipation within it (and save it from an additional hole needed for the power wire).You attached the tubes vertically rather than horizontally like my design. I also thought to do the same while designing, much more clean and less waste of space. However, I would have lost directionality of the airflow and detachability (for when I just need the ice chest as a picnic chest). With a more complex design I would probably be able to achieve the same with a vertical connection, but I'm not sure if it worth the hassle.Yes, I'm already on that path, too late to come back. The show must go on and before the end of the summer because from where I'm writing this message is nearly 90F!!

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 02, 2024, 11:37:50 pm
content: To reduce the heat introduced from the air intake it came to my mind the idea to use a peltier module:For simplicity I omitted the water pump and many other irrelevant details from the diagram.Basically I changed the position of the air intake to the vertical wall and the peltier module system just on top.The air sucked from the outside through the air intake will have to go through the COLD heatsink.A Peltier module does not create cold, but only transfer heat and I think this is probably what I want:by redirecting a certain amount of heat back to the room, the radiator, the water pump and in general the whole system, will stay colder resulting in an airflow with lower temperatures. The ice from the reservoir should also last longer because the water pushed back from the radiator should have a lower temperature.Maximum size of a peltier module is 50mm square size with 40mm being the most used one. Pretty small, but I think enough to process a good amount of heat.Mine could be a very bad idea and in contrast with thermodynamics, but intuition combined with my sixth sense make me think that could work.Apart my peltier module (crazy?) idea, I have a concern about my original design. The position of the air intake:All designs I saw are based on the first diagram. The air intake is basically placed as far as possible from the radiator and I suspect the main reason is to keep the radiator and the water as colder as possible (the same reason for which I thought to the peltier module). However, the air intake placed just above the radiator like the second diagram should prevent a good amount of heat from getting into the working system.I feel like the two options are going to produce different results and the second one does not necessarily means worse results especially with my design (which, unlike the common ones, the cold reservoir is kept on a separated and well insulated container).I'm in doubt and I'm afraid we are again into thermodynamics which is obscure territory for me.At this point I think I can proceed to buy all the missing parts and I can't wait to post here the results of my project!I still have concerns about optimizations and issues described in my previous message, but there is time for this, as is it should work wonderfully.Thanks to all again especially toIanB.

author: IanB
author_rank: Super Contributor
timestamp: August 03, 2024, 01:44:13 am
content: Quote from: YouCanDoIt on August 01, 2024, 09:47:28 pmBut you cannot make it colder. Assuming water is the working fluid, the lowest possible temperature of water is 0°C. Which means you can never make the water going through the radiator colder than that.QuoteUnfortunately, the temperature of the airflow has no bearing at all on efficiency of the system, other than personal comfort if you want to sit in the breeze.Quote from: YouCanDoIt on August 02, 2024, 11:37:50 pmUsing a Peltier module can only make things worse. A Peltier module consumes electric power, and power is heat, and heat is not wanted. This is for the same reason that putting a refrigerator in the middle of a room with its door open will heat the room up.Here is a simple calculation for cooling a room, if we assume the ice chest contains water ice. The calculation with gel packs will be similar, but I don't have the numbers for those. Also note that none of these calculations will involve the temperature of the cold air flow.Firstly, assume a typical room size of 4 metres by 4 metres by 3 metres. We will assume the room is perfectly insulated and no heat can get in from outside (not true in reality, but gives a best case scenario).The volume of the room is thus 4 x 4 x 3 = 48 m³The density of air is 1.293 kg/m³.Therefore the mass of air in the room is 48 x 1.293 = 62 kgThe specific heat capacity of air is approximately 1 kJ/kg/degC.Therefore, suppose we want to cool the room down by 5 degrees C, then the heat removal required will be:M cp ΔT = 62 x 1 x 5 = 310 kJThis is the amount of heat to be removed to cool the room air down, one time only, by 5 degrees.Next, consider the ice (the source of cooling).The latent heat of fusion of ice is 336 kJ/kg. This is nearly the same as the heat removal calculated above.Therefore, it will take about 1 kg of ice to cool the room down by 5 degrees, once, assuming the room has perfect insulation.In reality of course, the room is not insulated, and it will keep warming up again. The rate of heating depends so much on the room, but let's assume it happens in less than an hour.How much ice can you put in the ice chest? Maybe 10 kg? It depends on how big it is.So I think the device could achieve a little bit of cooling, for a short while.Probably it is better not to try to cool a room down, but rather to direct the cooled air directly at you, and just enjoy the cool air flow while it lasts.

author: IanB
author_rank: Super Contributor
timestamp: August 03, 2024, 01:56:57 am
content: A follow up note. A small window air conditioner might be able to remove about 5000 kJ of heat from the room air per hour. This clearly is vastly more cooling than the little ice box thingy can achieve. So I would not expect too much from it in terms of actually cooling a room down.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 03, 2024, 11:09:59 pm
content: Quote from: IanB on August 03, 2024, 01:44:13 amGood point! Well, in this case we want to be as close as possible to 0°C. But are we sure that water will not go below 0°C when there are several gel ice packs submerged?Yes, water, it's the only fluid I saw in such projects and I can see why: the cold source is basically free from costs. Are there better alternatives?Quote from: IanB on August 03, 2024, 01:44:13 amI'm afraid we're again in thermodynamics territory which is in contrast with what seems obvious to expect. At least there is the advantage to get immediately some comfortable breeze without waiting for the time needed to cool down the room.However, if I have understood well your previous statement, you seem to confirm what was my belief: getting the cold reservoir as close as possible to 0°C should be one of the target to reach.The thermal camera screenshots I posted shows 67.9F (20°C) coming out from the reservoir and I'm not sure why such high temperature. The other project (the one with smaller motor and one air intake) shows a temperature of 1.5°C.Given that both the configurations are pretty much the same along with the parts being used, I suspect that is the secondary air intake that ruins the internal temperature. It seems that for maximum efficiency, I need to identify the correct number of air intake and their dimensions. And such choice is strictly related to the blower motor size, its power, radiator type along with many other details of the cooling system. I think this will be the hardest partQuote from: IanB on August 03, 2024, 01:44:13 amPower consumption is something I must care about since low energy consumption is one of my main targets. The water pump is only 400ma, but the blower motor is 6A. I saw so many people talking about perltier modules power consumption and although I think to only need a 400mm block, the energy efficiency seems to depend from how the system is designed.Apart from consumption, I suppose you refer to the heat side (the hot heatsink) of the peltier module system showed in my diagram, right?What if we redirect the generated heat outside of the room just like does regular air conditioners?The modification of an existing window is a very cumbersome operation and not feasible. However, it should be pretty easy to get through a door with a small exit pipe with little or any modification at all. We could do the same even for whole working system although I believe it would be useless if we use a peltier module (which reduces the heat entering from the air intake through the cold heatsink).Quote from: IanB on August 03, 2024, 01:44:13 amMy room size should be approximately the same (at maximum 30% smaller) and all the other parameters you mentioned match.I'm afraid that trying to estimate whether it is possible to cool down a whole room to the desired temperature is a challenge.For example the "Deluxe DIY Air Cooler!" project seems to have a similar room with an additional hallway of unknown size. It's unclear about the time needed, but he has been able to drop the whole room temperature from 27C to 25C. Whether 2C drops is the maximum achievable or not I don't know.However, even if the desired temperature is only achievable on a limited area (let's say 2 cubic meters) it would not be bad although I designed the whole unit with in mind higher expectations.It would be great if 1 kg of ice can cool the room down by 5 degrees.The ice chest is 52QT, so I would say it should be able to contain around ten gel ice packs positioned vertically and probably additional 6-7 ones placed horizontally on top of them. Each gel pack is 1 liter and I can't find the weight on the specs.Hard to estimate, but I believe it should be more than 10Kg. Problem is that the refrigerator does not have such capacity (unless I take off the frozen foods).1 hour is the time lapse you estimate the unit will be able to keep the desired reached room temperature until the ice melt down and cooling capability ends up, is that right?Cool air in the project I have just mentioned lasted 4 hours using 2 frozen gallon jugs and a couple of regular ice-packs with a temperature dropped from 27C to 25C. There are too many variables that makes impossible an estimate, but under the same conditions, given how my unit is designed and the parts being used, I would expect at least twice (at worse).Quote from: IanB on August 03, 2024, 01:56:57 amUnfortunately in none of such projects I saw such data available, so I can't compare. Regular air conditioners have the advantage to transfer the heat outside the home. This is why I'm thinking to a peltier module integration. Probably my design for which I posted the diagram is not good because I suspect that the cold heatsink of the peltier system placed in front of the air intake still allows some heat penetration even if the heatsink is below 0C. There must be a way to completely redirect all the heat. Heat redirection should be probably the easiest task: a blower motor placed above the hot heatsink (rather than the black fan you see in the diagram), then a duct from the blower outlet until the room door, then a small adaptor that send the airflow into the slot located between the bottom side of the door and the floor (in this way I can even keep the door closed).However, what I see with an 8 row radiator like mine seems to give good hopes:Same location and conditions except that room temp dropped to 15C instead of 25C.Unfortunately I can't do any reliable comparison with the unit running under the bigger blower motor (the one for which I posted the thermal camera screenshots) because it has been tested outdoor, but even in such conditions the guy was still able to cool an area.So, before thinking to peltier systems and any other stuff I should focus on how to get all the available cold provided from the radiator because as is, with a 270CFM four inches blower, I suspect that a good amount of cold is lost.If you have any suggestions, please kindly let me know.Honestly I really don't know what to expect. Your calculations does not match at all what I see in similar projects, but it is better that I'm prepared even for the bad scenario you expect. And with this well in mind, I think that I should postpone the purchase of the temperature controller, am I right? If I will not be able to reach the desired temperature in the room, there is no point to regulate the blower speed based on the detected temperature because I will have to keep it running at full speed all of the time.Edit:A controller could be helpful even in such case. I could use it to regulate fan speed to cool just the target area, no more and no less.

author: IanB
author_rank: Super Contributor
timestamp: August 03, 2024, 11:50:38 pm
content: Quote from: YouCanDoIt on August 03, 2024, 11:09:59 pmThe unit in the video with the desk fan and the radiator is exactly like the illustration I posted above in the thread. This is, in my opinion, the simplest and most effective way to provide cool air in a room.QuoteNot quite. The air going through the radiator may have dropped from 25°C to 15°C, but the 15°C air immediately mixes with the warmer air in the room. The room itself does not cool down to 15°C.But generating a nice stream of cool air is a good benefit.QuoteThere is nothing to think about, and no cold is lost (except that which leaks outside the room through the walls, windows and doors). In the video, a big block of ice was placed in the bucket.Allof the cold in that ice, every bit of it, goes into the room. Guaranteed.The only way to lose efficiency is the power consumption of the fan motor and the water pump motor. The power going into these motors becomes heat that tries to warm the room up. But there is nothing much you can do about this, so you just have to accept it.QuoteHave you seen anyone else do a calculation? Yes, absolutely, you should not worry about temperature controllers. There is no real point.The calculation is simple. You bring ice (or cold packs) into a room. While the ice or cold packs are melting, they are cooling the room down. When they have finished melting they are done and no more cooling is available. The only purpose of the water pump, radiator and fan is to help bring the room air into contact with the cold source and circulate the air around the room.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 04, 2024, 02:48:55 am
content: Quote from: IanB on August 03, 2024, 11:50:38 pmYes, I remember. At this point I'm really curious to see what is the most efficient. The guy built both, so I'm going to ask more details. What I saw by reading the discussion is that with the blower motor version he was able to cool down the whole room while with the box fan version he just said that it does a nice job of cooling a small to medium size area (which is unclear what exactly means).Yes, you're right! 15°C is the air going through the radiator and this is a whole completely different story. He didn't mentioned any change in the room temperature, so I start to believe it only works as a stream of cool air.One thing to take into account is that humidity matter and the reason for which the other guy, with 32% humidity, chose a blower fan which can withstand with moisture. Here we are at no less than 50%.High humidity can cause many issues. A box fan is more suitable for dryer climate and from what I see in the comments, there are still chances of issues. It's still possible to overcome such issues even on humid climate, but requires an additional system.Quote from: IanB on August 03, 2024, 11:50:38 pmI must admit that I am a bit confused. The guy that built such systems said that air not getting through the radiator can be one of the many reasons for inefficiency and given that I'm sucking air from a 250mm x 300mmm radiator through a 102mm fan, to me seems that 2/3 of the cooling capability of the radiator is lost. If I can only target a 102mm area, than I'm wondering what would be the advantages of a bigger radiator like this.The guy also seems to consider the output temp as the main factor that affect cooling capability, the exact opposite of what you say. I'm not saying that he is right and you're wrong. I'm just trying to understand why such conflicting opinions in order to see on what I should be focused on.High humidity is another important factor he included in the list and given I have no less than 50% I should start to think of a possible implementation to overcome this issue.I'm afraid I'm doing the mistake to fix the issues without even know if they are issue I will have to face. The best I can do is to build the system as is and later see what can be improved.Quote from: IanB on August 03, 2024, 11:50:38 pmI should always keep in mind your very simple explanation on how works cooling. However I still think that many other parameters play their own role (like for example the air intake number and dimensions, the guy that built the "Deluxe" cooler explained the details in the notes).Regarding the temperature controller, see my edit. May be I can still get some benefits if I reduce power only to the minimum necessary to cool a specific area rather than trying to cool the whole room at max speed (which would be a waste of resources if the system is unable to complete such task). Heat generated from water pump and fan should also decrease with less power. Not to mention about noise reduction.I'm doing again the mistake to find ways to enhance functionalities without even know if there any functionalities that need to be enhancedP.S. You didn't said what you think about my idea to redirect the peltier module generated heat out of the room. This was what you said to be the bigger issue. Pretending that my idea work, do you see any benefit from preventing the room heat from entering inside the system through the air intakes?

author: IanB
author_rank: Super Contributor
timestamp: August 04, 2024, 03:53:38 am
content: Quote from: YouCanDoIt on August 04, 2024, 02:48:55 amI don't think a Peltier module has enough capacity to make a difference when cooling a whole room. The golden principle in engineering is "keep it simple". Even if you could redirect the heat from the Peltier module outside the room, it would just be adding complexity to the whole arrangement. I would never even think of it.No, there is no benefit preventing the room heat entering the system through the air intakes. No benefit at all.You bring ice into the room. When the ice is melting, it absorbs heat from the room, and cools the room down. It really doesn't matter how the room heat gets to the ice, it cools the room down just the same.The simplest possible design is to put a big block of ice on a tray in the middle of the room, and arrange for a room fan to blow air over the ice. This is as efficient as you can get. All the cold gets into the room, and no cold is wasted.Every other design is just adding cost and complexity to that, with no improvement in efficiency. The only advantages of other designs are:1. Maybe they can cool the room down faster2. Maybe they can regulate the cooling to make it last longer3. Maybe they are more convenient to operateKeep in mind the definition of efficiency in this context:Efficiency = (Total cooling delivered) / (Total cooling available)If you bring a block of ice into a room and let it melt, the efficiency is 100%, because all the heat to melt the ice came from the room.If you make a contraption with fans and motors and pumps, the efficiency is less than 100%, because the motors generate heat which is the opposite of cooling.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 07, 2024, 05:41:52 am
content: You're right! There's a guy who tried and with a very well done design, but without success even with 4 modules:He said that to get any noticeable result much more modules are needed and combined with expensive copper coolers. I don't even want to think to power consumption.I excluded a DIY air conditioner powered by peltier modules from the beginning.However when designing the current project I wondered if ice + one module combo could improve the cooling capability.More than an additional source of cold I thought to it as a way to prevent heat from entering inside the container, but I think I have understood what you mean: the heat has to enter in order to be converted into cold. So, a peltier module is counterproductive.I'm correct if I say that I should try to do the exact opposite like trying to get inside the container more hot air as possible and with the more possible highest flow rate?Quote from: IanB on August 04, 2024, 03:53:38 amEh eh, a bit complicated, but efficient for sure!Quote from: IanB on August 04, 2024, 03:53:38 amIf the cooler is pointed against me, I could be wrong, but I don't think it will be very noticeable when the room will reach the target temperature whether will be after 5 minutes or 30 minutes.Second point is the more interesting one. A longer ice retention is probably the main thing we desire especially when on travel.For the third point I still have to figure out concrete advantages.Thanks for the formula! This is the first thing to have always in mind when trying to find improvements.The guy responded me and said that it is hard to compare, but with the blower motor version, temp drops can be 10 to 20 degrees and more. Well, I would say that it is really amazing, but other people that followed the exact design only got 2 degrees less.There must be some other factor and I'm afraid that humidity plays a role. Seems to be that cooling is much easier in a dry climate. If I can't get good results I should think on how I could integrate into the system some sort of dehumidifier.I have ordered all the parts, or better, the ones essential to get something up ad running. I will keep you updated.My only concern is how to attach the parts on a styrofoam box. I suppose that regular screws will not work. Hope there is something better than glue.

author: IanB
author_rank: Super Contributor
timestamp: August 07, 2024, 05:59:07 am
content: About humidity. If the room air is very humid, and the radiator is very cold, then moisture from the air will condense on the radiator. When the moisture from the air condenses it will release heat, which will cancel out some of the cooling. So, if you do have humidity, you don't want to cool the air down too much in the cooler as this will be counterproductive. On the other hand, dry air in the room feels cooler to the skin than humid air and maybe dehumidifying the air in this way is good. I don't really know what is going to work out best.If you want my honest opinion, you can overthink these things, and get too caught up in the details. Just build something, see how it goes, and maybe next year build something different.You understand, of course, that when you freeze your ice or gel packs, the freezer must be in a room far away from the room you wish to cool, otherwise the heat from the freezer would start warming up the interior space. If (worst case scenario) the freezer was in the same room you are trying to cool, you will just be creating a room heater.

author: tooki
author_rank: Super Contributor
timestamp: August 07, 2024, 01:16:27 pm
content: Quote from: YouCanDoIt on August 07, 2024, 05:41:52 amIn terms of energy: Cold doesn’t exist. Heat exists, and cold is simply the absence of heat.A Peltier element does not generate cold, and it certainly does not “convert” heat into cold. Like any refrigerator or air conditioner, it simply moves heat from one place to another. And to do so, it itself converts some electrical energy to heat as well.What I mean is that a Peltier element absorbsnamount of heat on the cold side, and then outputs >namount of heat on the hot side.So if you have both the hot and cold sides of a Peltier element or other refrigeration device in the same space, you will simply heat up the space. Peltier elements are much less efficient then compressor-based refrigeration, so Peltier elements would just heat your room up extra.The only reason we can use real air conditioners is because we can separate the cold and hot sides, so that the heat is being deposited outside the house.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 07, 2024, 10:43:43 pm
content: Quote from: IanB on August 07, 2024, 05:59:07 amWell, during this period I monitored the humidity which has been all of the time at around 50%. When it rains can reach even 60-70% and even if temperature decreases it is still not comfortable. I suppose it will be even more problematic running my air conditioner in such scenario.Yes, I will first build something and then I will check how will handle humidity. I have just given a quick look on youtube about DIY dehumidifiers and they look like a portable air cooler.The same guy that built lot of air coolers has built one:Design is pretty much the same as mine. So I'm wondering if mine is already a dehumidifier. If not, it should be pretty easy to implement the feature with some minor changes.I'm totally surprised on what you say about the freezer. Being two distinct devices i would have never suspected they could interact in such way. Fortunately the freezer is located in another floor of the home where there is a real AC (I suppose freezing the ice packs will not affect the AC in any way).Quote from: tooki on August 07, 2024, 01:16:27 pmI should see things exactly as you described, it would make understanding cooling much better. However, cold and heat are two phenomena that our body feel and distinguish very well, so it is very easy to end up with the non energy point of view.Yes, in fact my idea about the peltier module was not to generate cold, but redirect the heat coming inside the processing unit out of the room through a pipe. I thought to it to some sort of helper, but seem to be that it cannot work.I can see the downside which is the same described from IanB.So, rather than combining my AC with peltier modules and other similar systems, I should focus to improve design of my AC.Currently, I strongly suspect a big flaw in my design. The radiator size is mm 254 x 304 x 20 while the in-line blower motor only 4 inches. I suspect it will not be able to suck most the cold provided from the radiator. As of now the only workaround I can think of is adding one or more blowers. If you have some better suggestion, kindly let me know.Quote from: tooki on August 07, 2024, 01:16:27 pmApart the bad peltier module idea, I would like to add some mechanism to my AC to separate at least part of the heat and get it deposited out of the room, but I suppose this is not possible for the way my AC is designed.

author: themadhippy
author_rank: Super Contributor
timestamp: August 08, 2024, 01:10:27 am
content: Quotecheapest would be salt water,35 grams of salt to 1 liter of water will get you to-1.8C,but then you've the problem of corrosion.Propylene glycol is another cheapish option 40% glycol/ 60% water gets you down to around -20C

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 04:33:15 am
content: Quote from: ebastler on August 07, 2024, 06:32:06 amAre you saying that the styrofoam box is the wrong material for the processing unit? Or that I should leave all of the parts exposed?Well, mainly because styrofoam is cheap and good for insulation. Without a container it would be a much more complicated mechanical construction and the related parts more easily exposed to possible damages. Also, the radiator will be more subject to condensation which, from what I have been told, is something we want to avoid like pest.Regarding air velocities and fan speeds,I saw similar projects running fine even with a 3 inches 130CFM variant (see the video below). However with much smaller radiators and you got the point on what is my main concern. In order to get all the cold from the whole area of the radiator, I'm not sure a 4 inches 270CFM is enough, even if there is a suction duct. As of now I can't think of to any other solution than additional fans.Whether is better a marine blower or a large box fan is something I saw is highly debated from people that built such kind of projects. One issue with the latter is moisture and this is something even more problematic in humid climates. Where I live is 50% minimum, so a SEAFLOW blower designed to withstand with moisture seemed the best solution.I should also note that unlike the blower marine motors designs, I still have to see a box fan project able to effectively reduce a room temperature. They seem most suitable to stream some cool fresh air against some reduced area.Quote from: ebastler on August 07, 2024, 06:32:06 amThe purpose of the carbon/Hepa filter on the air inlet is removing contaminants from the room. Contaminants get stuck into the filters and cold air is released into the room clean. This is what does a famous guy on youtube who continuously build such kind of systems (and the only one I saw who successfully decreased a whole room temp by 10-20C° with an unit like the one you see below):Only difference is that I've increased filtering capacity with a carbon+Hepa combo. Here is another reason for which a container is needed (styrofoam or what else). With a box fan version of the project it would be much difficult, supposing it can be done.Airflow obstruction is something I have considered, but when I saw that system running fine with a 2.5" air inlet hole and much less powerful fan, I thought it should not be a problem.The goal here is not avoiding the introduction of new contaminants into the room, but eliminating the existing ones.If you want more info, this is the video related to the screenshots above:Regarding the noise, this is another thing that I have carefully evaluated and,at least on such kind of system, a 3" fan is noiser than 4" fan. I described this very detailed (on the previous page if I remember well).Quote from: ebastler on August 07, 2024, 06:32:06 amYou're right! I'm not sure if the radiator temperature will be close to 0°C. Look at the thermal camera screenshot I posted a couple of messages before. The temp coming out from the radiator is around 68F.If this event occur I could think to some mechanism to reintroduce the drips into the circuit rather than throwing away precious cold water. There must be some adapter with such scope in the market, but I have yet to investigate.Anyway, I deduce that getting the water as close as possible to 0C° should be one of the main target because means more cooling power and longer ice melting times. I prefer water near to 0C° plus condensation issues to fix rather than hotter water without any condensation issues. I previously discussed about this with IanB (see some couple of messages before) and there several ways to regulate water temp when gel ice packs are used. There are different variants, but I have not investigated. I've just purchased different brands and I'll see directly on the field how they perform.Quote from: themadhippy on August 08, 2024, 01:10:27 amthemadhippy, many thanks for this precious contribution!Investigating salt water was on my To-Do list and I would have for sure definitively forgotten if it wasn't for your post!Corrosion is something I was not aware of and for sure a big problem. I suppose there is no solvent to fix this or any other possible workaround.Uauhh! -20C should really make a big difference in terms of performance!If Propylene glycol is cheap and free from corrosion issues, than it may be worth. Are there particular issues that I should be aware of about Propylene glycol? My main concern is about health safety. the word Propylene glycol does not feel safe at all and I am not sure on the consequences for health if it get released into the room through the cold air.However, IanB recommended tonever go below 0C*, otherwise the radiator will not work. Do you have any experience on this?

author: IanB
author_rank: Super Contributor
timestamp: August 08, 2024, 05:32:19 am
content: Please read again this post:https://www.eevblog.com/forum/projects/i-need-to-connect-a-100mm-dryer-flexible-vent-hose-to-a-102mm-pipe/msg5592019/#msg5592019Temperature is not an important factor in performance. Colder is not necessarily better.A portable ice air cooler can never, under any circumstances, cool a room down like an electric room air conditioner.And I told you that water can never go below 0°C or it will freeze. If it is ice, you obviously cannot pump it through a radiator. This is not a recommendation. It is a law of physics.

author: ebastler
author_rank: Super Contributor
timestamp: August 08, 2024, 06:20:09 am
content: Quote from: YouCanDoIt on August 08, 2024, 04:33:15 amWhat do you want to insulate there? You want cold air to be released into the room. You had shared a video (in your other thread, I believe) of a fan blowing towards a radiator simply placed in the open -- what's wrong with that from a thermal perspective? You just need to add basic mechanical protection, i.e. a wire mesh cage or such, to ensure that the radiator is not damaged and the user's fingers are not hurt by the fan.Also, I don't see how the styrofoam box would prevent or reduce condensation on the radiator. You are blowing warm air at the radiator, which will get cooled down there and hence can't hold as much moisture, so you will get condensation.QuoteWe used to run a mobile air filtration unit when our son was little and struggling with allergies. It had a HEPA filter with amuchlarger surface area. The small filter you plan for will clog quickly, and will make your unit noisier and/or less effective due to restricted air flow.

author: themadhippy
author_rank: Super Contributor
timestamp: August 08, 2024, 12:10:20 pm
content: Quoteguess what they use in the beer coolers ?and It dont seem to affect the 100000's of beer drinkers supping chilled and super chilled pints,

author: soldar
author_rank: Super Contributor
timestamp: August 08, 2024, 12:20:17 pm
content: Quote from: IanB on August 08, 2024, 05:32:19 amWell, you can add antifreeze to water but reading this thread I think the best advice is the first phrase " A portable ice air cooler can never, under any circumstances, cool a room down like an electric room air conditioner.".Seeing this type of projects I get the feeling that the people doing them just do not understand the basic laws of physics and believe they can find work around them.In the summer heat it is the "put some cubes of ice from the refrigerator in front of a fan" and in the winter cold it is the "put a burning candle under an up side down clay pot to heat all your house". Or the "ceramic electric heaters".

author: Siwastaja
author_rank: Super Contributor
timestamp: August 08, 2024, 12:35:15 pm
content: It makes little sense to overengineer a ghetto cooler. Use duct tape and whatever to make it work, from any trash parts you can find.And yes, others are right about not needing colder temperatures. Thermal capacity of ice is crap anyway, it warms up to 0degC pretty quickly, regardless if the initial temperature is -10 or -20 or -30 degC. It's the phase change from ice to water which stores (and releases) most of the energy, and this happens at 0degC pretty exactly.But this is not a problem at all, ice at 0degC is more than fine for cooling. Remember that temperature and energy are two different things. You can cool with material at 10degC, 0degC or -10degC equally well providing same cooling effect, just requiring some more surface area and/or airflow if the temperature isn't as low. Actually you don't want to cool with colder than 0degC material because then room humidity freezes and finally blocks whatever radiator type you are using. Another thing you don't want to do is to cool with >15degC water; even if you can cool with say +17degC water (using large enough radiator and air flow), it won't have drying effect which is often desirable in humidly hot conditions. If you just cool without drying, relative humidity just rises and it still feels uncomfortable. But if you run say +10degC water in your radiator, then it is already capable of drying the air down to dew point of approx. that 10degC (or a bit more), which is already very comfortable.The biggest problem in ghetto coolers is the capacity of typical household freezers. Even if the freezer was conveniently located in a far enough room so that its heat output doesn't ruin your cooling, you would still need to keep swapping ice packs nearly 24/7. The freezer compressor runs nearly non-stop and freezer's inside temperature rises; so you can't use it for storing foods at the same time, they get spoiled.Therefore these ghetto coolers tend to be good only for short demonstrations; you freeze a few liters of water and you can feel how it really works. Except that after 3-4 hours you are out of cold. Even if you did put more water bottles into the freezer, they are not frozen yet. The capacity isn't there: compressor power is some 200W and COP pretty crappy like 1.5-2 at most. Real air conditioners have higher evaporator temperature (remember: it does not try to cool anything to -20degC like a freezer does) and lower condenser temperature (it has a decent fan-cooled coil, not some tiny convection cooled grille on the back like freezer) so much smaller differential and therefore COP like 3-5, and still you would like to have at least 500W of input power for serious cooling.Maybe with two-three typical household freezers, located on a balcony or something so that they don't heat up the house, only dedicated for ghetto cooling, you could do this continuously, sure. But if you don't have even a single dedicated freezer, it's only going to work for short demonstrations, and as such is not worth investing a lot of time and design into. But, because it's an interesting experiment, I don't want to shoot it down either: therefore, duct tape!

author: tooki
author_rank: Super Contributor
timestamp: August 08, 2024, 12:56:43 pm
content: Quote from: soldar on August 08, 2024, 12:20:17 pmThat is an understatement! 😂

author: BrokenYugo
author_rank: Super Contributor
timestamp: August 08, 2024, 02:03:57 pm
content: Think of it this way, at least in the US we have a somewhat backwards (as is traditional) old way of specifying cooling capacity for buildings, in tons of ice. E.G. a 2 ton AC (typical of a small 3 bed house or medium size car) running flat out cools as well as 2 tons (1815kg) of ice melting over 24 hours.You'd have to be shoveling in ice to such a device (nevermind the source) to keep up, even a little half ton window unit works out to 18 kg/hr. There's a reason we abandoned using ice blocks for any general cooling needs as soon as refrigeration tech allowed, it just isn't that great unless you've got nothing better than cutting up frozen lakes over the winter and storing it in big insulated buildings through the warm months, and that mostly just kept food cold.https://en.m.wikipedia.org/wiki/Ton_of_refrigeration

author: IanB
author_rank: Super Contributor
timestamp: August 08, 2024, 02:36:31 pm
content: Quote from: BrokenYugo on August 08, 2024, 02:03:57 pmThis is, however, a very practical and comprehensible way of describing things, since as we have seen the concept of energy balances is not easily digested.If we understand that a 1 ton air conditioner can freeze 1 ton of water (1000 kg) per hour, and if we then we think about replacing that with a domestic freezer, we see how absurd the situation is. We would need our freezer to freeze 1000 kg of water every hour to be equivalent to a small room air conditioner. It would need a whole warehouse full of freezers to do that.

author: tooki
author_rank: Super Contributor
timestamp: August 08, 2024, 02:50:32 pm
content: It is interesting that ice-as-energy-storagedoesmake sense in some circumstances, and is used in practice. For example, ice-based air conditioning systems for large buildings, in places where electricity is cheaper at night. Rather that using daytime electricity to directly cool the building air, those use cheaper nighttime electricity to freeze HUGE amounts of water, then use that ice during the day to help cool the building air. But we are talking about literally tens of thousands of kg of ice being created and remelted daily in a small installation. And as I understand it, they typically only augment the refrigeration with the ice, and do not rely on ice entirely during the day.(Amusingly, one company that claims to be the biggest manufacturer of such equipment is just down the road from where I used to live in Maryland!)

author: MisterHeadache
author_rank: Regular Contributor
timestamp: August 08, 2024, 02:53:29 pm
content: The effect of the humidity of the room air cannot be minimized. It's been a few decades since I did these calculations in MechEng thermodynamics classes, but I do remember the basics of using what's called a 'psychrometric chart'. Look it up and how to use it. Once you cool the room air to its dew point (meaning 100% relative humidity), a big portion of the energy required to cool it further is just consumed to condense the humidity out of the air as you cool it further. For example: if you start with a room with 80°F air at 80% humidity, your efforts to cool it will drop the air temperature and raise the relative humidity until you hit 100% relative humidity at its dew point (73.3°F). Cooling it further begins condensation and now a significant portion of the energy transfered is condensing water, not just cooling the air further. So that's kind of an efficiency loss - some of the energy you'd like to use productively (reducing the room temperature) is 'lost' in just making condensed water that you don't value.If you start with drier air at a very low relative humidity (Arizona for example), you can cool it to a much lower air temperature with the same available energy because you won't be condensing hardly any water from it.

author: IanB
author_rank: Super Contributor
timestamp: August 08, 2024, 03:06:28 pm
content: The balance with humidity is the perceived air temperature and comfort levels. If the room air is dehumidified, even at the same temperature, then the occupants may feel more comfortable because skin perspiration becomes more effective. So cooling power used to dehumidify the air is not necessarily wasted.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 05:41:49 pm
content: Quote from: IanB on August 08, 2024, 05:32:19 amYes, I have done and invite you to read my response along with the posted comment from the guy that regularly build such kind of devices. He states the exact contrary and he do this in every project he publish on youtube.I think that we agree on the two following points:The lower is the temperature of the water inside the cold reservoir, the longer will take heat to melt ice packsThe lower is the temperature of the water inside the cold reservoir, the lower will be the temperature of the airflow released into the the room resulting in faster cooling times and higher chances to bring room temperature downWhen you say that temperature is not an important factor in performance and colder is not necessarily better, you probably mean that a colder temperature could generate moisture issues and you're perfectly right.However, as I already said to ebastier, I prefer water near to 0C° plus condensation issues to fix rather than hotter water without any condensation issues.Quote from: IanB on August 08, 2024, 05:32:19 amIf this is not possible and under any circumstances, then the "guy is lying":Or, more simply, it depends from how well the system is designed. I exclude the small room size as a mandatory requirement just because a bigger room requires a bigger system.Quote from: themadhippy on August 08, 2024, 12:10:20 pmThis is a great news! However, IanB can correct me if I'm wrong, this can't work in any way. A -20C temp drops will bring water below zero. It can only work if the water temperature is around 25C, but the ice packs alone will bring temp much down than that.What makes me suspicious about this solution is:why no one has ever attempted to replace ice packs with Propylene glycol? It would be much less hassle and the system would be truly portable because without relying on ice it can work literally in any place.If I remember well, I have read that antifreeze is dangerous for health. You're probably right when you say that most people don't understand the basic law of the physics. Given that such laws can't be bypassed and that guy achieved the goal, I suppose he just designed the system to use the physics law in the right way. I don't know how compares with a regular AC, but it is not certainly at the same level. However with a 10-20C temperature decrease I would consider this more than satisfying.

author: ebastler
author_rank: Super Contributor
timestamp: August 08, 2024, 05:53:37 pm
content: Quote from: YouCanDoIt on August 08, 2024, 05:41:49 pmYou may be mixing up two things here? Propylene glycol does not magically get cold on its own. It is just a liquid with a lower freezing (or melting) temperature than water.The total cooling capacity of your system (i.e how much total heat energy it can "extract" from a room) is determined by the total energy it takes to melt the ice blocks you put in. Whether the heat transfer happens through slightly warmer or colder water (or some other liquid) may impacthow long it takesto melt the ice.QuoteNo, we can't agree on that. Those two points are actually contradictory. If it takeslongerto melt the ice packs, then heat from the room is transferred to the ice packs less efficiently. So it will takelongerto cool the room down.Edit: Typo

author: Siwastaja
author_rank: Super Contributor
timestamp: August 08, 2024, 06:04:56 pm
content: Quote from: MisterHeadache on August 08, 2024, 02:53:29 pmThis is technically correct, but maybe a bit misleading: you would not gradually cool the room towards dew point and then start drying. This would happen with infinite air flow over ideal (infinite performance) evaporator coil.Realistically, any air conditioning solution would keep the indoor unit coil temperaturesignificantlybelow target room temperature, in other words, air flow modest and not excessive, so that humidity is continuously removed from the beginning, and this cold (absolutely quite dry even if 100% RH) air mixes with the warmer room air, gradually bringing both temperature and absolute humidity down at the same time.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 08, 2024, 06:10:05 pm
content: Quote from: ebastler on August 08, 2024, 05:53:37 pmYeah, and to be super clear, this is exactly what we do NOT want. We do NOT want prevent the storage medium from freezing. Solid<->liquid transition is exactly what stores a lot of energy in relatively little weight. If you prevent freezing by using antifreeze such as glycol, you would need many hundreds of liters of it to have any effect at all.Sure, freezing is a bit of problematic transition because it physically breaks stuff due to how the volume changes quite violently (it can crack rocks), but any even remotely portable solution has to deal with this.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 08, 2024, 06:19:25 pm
content: Quote from: tooki on August 08, 2024, 02:50:32 pmI have been playing with this idea of taking an commercial off-the-shelf ice cube maker - maybe a professional higher throughput version, something being used at McDonalds and the like, something with serious continuous power rating. They already solve all the hard engineering work of not only making the ice, but separating it from the evaporator coils without damaging anything. Run during cheap electricity (nighttime, or maybe solar panel self-use), store the cubes in large insulated styrofoam/etc. boxes. Replace box lid with a fan unit which blows air over the ice, and voila. As long as there is ice in the mix, the water surface keeps close to 0degC and thus it keeps dehumidifying. Extracted humidity ends up mixing with the melting water, but so what. Once melted, you swap boxes.For this to become an actual product, we really would need to combine the outdoor unit of a split air conditioner, with the ice cube maker (evaporator only) working as the indoor unit, and then automate the mechanics of moving around the ice cubes.Water could be reused a few times, but probably for sanitary reasons simpler and safer to use fresh water every time - ice cube makers already have solenoid valve controlled water input so most of the engineering is already done.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 06:57:59 pm
content: Quote from: ebastler on August 08, 2024, 06:20:09 amWell, under the thermal prospective I initially thought that would help to keep the unit colder. I suppose it should make difference between hot air penetrating through an air intake vs all the parts exposed to the room hot air.Then, IanB pointed out what you're trying to say, but there are still many other issues other than a more complicated mechanical construction (inside there is not only the radiator to protect and the number of parts you see in the diagram can increase if the processing unit is enhanced with more features). I don't even want to think on how this reduce portability since this is not my main concern (but something that for sure plays against such design).I think you refer tothisvideo. This, along with many other I saw, seems to be not able to cool a room. They're more like "fans pushing gentle fresh air against a reduce area". I preferred to go with a design that has been proven to work and being free from issues I described in details with screenshots in this thread.I think you're right when you say that styrofoam box does not prevent or reduce condensation on the radiator andI suspect styrofoam material could even be counterproductive.IanB can correct me if I'm wrong, butinstead to prevent heat introduction inside the processing unit through styrofoam we want a material that does the exact opposite.Your observations about the air filtering are well motivated. I have no idea on how much filters can last, but given that the guy didn't mentioned anything about duration, I suppose they work for acceptable times. I have a regular AC in another floor of the home and they needs to be replaced once a year, but I really don't care if I have to replace once a week. Replacement only takes a couple of seconds, the sheets are very cheap and provides plenty of filters.However, I'm attempting to perform a nearly full room cleaning through a two layers Carbon/Hepa combo which is different. I guess I will have to do many trials before I find the right balance (number of holes, their diameters etc). At worse I can always fallback to the same 3M filters used by the guy. These, at least, are proven to work without any interference.

author: ebastler
author_rank: Super Contributor
timestamp: August 08, 2024, 07:21:04 pm
content: Quote from: YouCanDoIt on August 08, 2024, 06:57:59 pmMaybe a quick estimate can be helpful:A typical self-contained air conditioner based on a heat pump (those small vertical units on wheels) has a cooling power of 2.5 kW under ideal conditions. That's 9000 kJ per hour.A kg of water takes 333 kJ to melt, and another 120 kJ to heat by 30 °C (say from -15 to +15°C). Hence the effect of heating and melting a gallon-sized ice block (4 kg) will be equivalent to running that small air conditioner for 12 minutes. Underwhelming, isn't it?(This estimate is not discussinghow fastyou can extract heat from the room. It just estimateshow muchheat you can extract until all the ice has been melted and warmed up to nearly room temperature, at which point there will be no more cooling at all. I.e. the overall effect on room temperature you can expect to get from one load of ice, compared to what you can expect from a proper heat-pump cooler.)I think the hero of the videos you shared is kidding himself. He may get a nice refreshing feeling from blowing cold air at himself for a while; but the effect on overall room temperature will be very limited indeed.

author: IanB
author_rank: Super Contributor
timestamp: August 08, 2024, 07:50:12 pm
content: Quote from: YouCanDoIt on August 08, 2024, 05:41:49 pmThis is not true.QuoteAgain, this is not really true.QuoteNo, I simply mean that temperature is not a significant factor in any performance calculation.QuoteCondensation could be good because it will dehumidify the air.QuoteNot so much lying, just mistaken.Let me try to give you the basics one more time.A room air conditioner takes heat from the room and dumps it outside. Its performance is measured in how much heat it can remove per hour (e.g. kJ/h in Europe, Btu/hr in America). There is no mention of temperature here.With an ice-based cooler, you are replacing the air conditioning unit in the window with a freezer in some other room. But the capacity is still measured in the same way. How much heat can the freezer remove from the internal contents per hour? (How much water can it freeze per hour?) The answer is a small number: much, much smaller than an air conditioner.The electric air conditioner could freeze the equivalent of 1000 kg of water per day. If you put 1000 kg of water in your freezer, how long will it take to freeze? Can you even fit 1000 kg of water in your freezer?You can see there is no way an ice cooler can match an air conditioner. It will not do much more than provide a cool breeze for a short while.And once again, no mention of temperature. Temperature just doesn't come into the calculations.I think I am over and out here. There is nothing more to say.(Edit: corrected mistake in tons of cooling, it is per day, not per hour)

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 09:18:14 pm
content: 5 stars for Siwastaja!! He explained perfectly well the pros and cons of colder temperatures and provided samples on how to achieve the right balance!Quote from: Siwastaja on August 08, 2024, 12:35:15 pmYou're probably right, but overengineering is so funny!!Quote from: Siwastaja on August 08, 2024, 12:35:15 pmDoes this applies to gel ice packs too? I know there are several variants andhereare discussed all the technical details. I tried to follow the discussion, but is very advanced stuff and I just preferred to buy mixed brands and see what are the ones that work better.Quote from: Siwastaja on August 08, 2024, 12:35:15 pmYou said that I can cool with material at 10degC, 0degC or -10degC equally well providing same cooling effect, just requiring some more surface area and/or airflow if the temperature isn't as low.Does this means that a colder temperature is not totally useless and still have the desirable advantage to require less surface area and/or airflow?If I have understood well, on the other side, I don't want to cool with air which temperature is higher than 15C.The guy from which I posted the amazing unit which cooled down a room temp by 10-20C got an output temperature of nearly 2C (its climate is dry):Do you think that 2C is the correct balance (with the previous mentioned advantages included) ? Keep in mind that my climate is humid (around 50%). I don't know why didn't worked for the other 2 guys, there are to many variables that should be checked included dry vs humid climate. Plus my design is completely different, so I can't really compare.Quote from: Siwastaja on August 08, 2024, 12:35:15 pmFortunately the floor of my house where there is the room I want to cool is free from any household freezer.The annoyance of swapping ice frequently is pretty much inexistent. That cooler, with a 28QT chest (3 days ice retention advertised), 2 frozen gallon jugs and a couple of ice-packs, latest 4 hours. Good for daytime, but not for nighttime.Mine uses a 52QT chest (6 days ice retention advertised), it is nearly fully insulated and uses gel ice packs in higher quantities. I expect much longer duration and good even for nighttime.Quote from: Siwastaja on August 08, 2024, 12:35:15 pmThis is something that I have not considered at all. My freezer is pretty new technology, but apart from this I can't really imagine how this can happen. Freezer's inside temperature rises each time we introduce new food, but this is just how they are designed to work. Do you recommend to pre-cool the ice packs in the fridge?Quote from: Siwastaja on August 08, 2024, 12:35:15 pmI have several ice packs, so while my cooler is cooling, at the same time the freezer is freezing the ice packs for the next cycle. Yes, with a cycle that lasts 3-4 hours, the next ice packs supply is not ready yet, buy given how I designed the cooler, I expect much longer duration, even more than the time needed to freeze a one cycle supply.Now, given that all my estimations are right (and there's no guarantee), I'm correct to deduce that the only concern could be the power consumption of the freezer (which should not make much difference anyway because I'm using one freezer only with the highest energy saving rate) ?It would be very interesting to hear the opinions of that guy about such statements especially. The results he achieved are in contrast with what stated here from several users. I'll invite him to join the discussion, I'm sure this thread will become more interesting if there are people with different opinions (which unfortunately seem to lack).

author: ebastler
author_rank: Super Contributor
timestamp: August 08, 2024, 09:38:51 pm
content: Quote from: YouCanDoIt on August 08, 2024, 09:18:14 pmYou are not getting it, are you? You can add as many complications, bells and whistles to your cooler as you like. Ultimately, the amount of heat that one load of ice can extract from the room is equal to the energy it takes to heat and melt that load of ice. Which is, unfortunately, a rather small amount. You can't beat physics there.You don't have a formal education in thermodynamics, which is alright. You also don't have a good intuitive feel how heat capacity, heat transfer and insulation work, which is a pity. And you seem either unwilling or incapable of extracting the relevant information from many posts where various forum members have tried to explain some of this stuff, which is annoying.Why don't you just go ahead and build something. Either you will like the result, or you will learn something. In the meantime, I will resist the urge to make a pun about your username, but I will be out of here.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 09:41:14 pm
content: Quote from: BrokenYugo on August 08, 2024, 02:03:57 pmQuote from: IanB on August 08, 2024, 02:36:31 pmWhat you say guys is highly demoralizing, but it is science and the truth of science can't be modified as our liking. I would have preferred to be aware of such truth right from the beginning.At this point I'm wondering if my project could be nice to cool a small area of the room as IanB originally suggested. It would be a nice result anyway for me, even more if I can get longer operating times (which has always been one my main targets). If I have to move in another area I can just change direction of the airflow and this would be perfectly acceptable.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 10:52:37 pm
content: Quote from: MisterHeadache on August 08, 2024, 02:53:29 pmQuote from: IanB on August 08, 2024, 03:06:28 pmGuys, can you give me at least one good news every 5 bad news?Although I'm not even close to your knowledge in this materia, I was aware from the beginning of the bad things when the cooler continue to aggressively output cold air after the target temperature is reached.For this reason it was on my purchase list a temperature controller which regulates fan speed and water pump power based on the detected temperature. Just like does a regular AC, once the target temperature is reached it slow down with some sort of "maintenance mode".However, from your opinions seemed to be very hard to cool down a whole room at least at a minimum comfortable temperature and this means that the cooler need to run at max power for all of the time. So, a temperature controller does not help at all. May be it could be helpful if I want to cool only a small area and the required cooling power for such area is less than the maximum that the system can provide.Today Arizona humidity is 32%. I previously posted a screenshot from a guy that live in Las Vegas. He got the same 32% humidity and said it was enough for some condensation. Right now in Las Vegas is 21%. Shouldn't Las Vegas climate be more humid than Arizona?With 31C and 50% I would say that I'm in the middle. What I can expect?So, decreasing humidity (even in a small room) is not possible in any way. What's the real purpose of dehumidifiers available in the market (or even the DIY one I've previously posted a video) if the achievement they are designed for can't is not reachable in any way?

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 08, 2024, 11:23:40 pm
content: Quote from: ebastler on August 08, 2024, 05:53:37 pmOps! You're right! I missed out the most obvious thing: a cold source is still needed, then the additive regulates temperature. Do you see any helpful usage of this additive in my scenario?Quote from: ebastler on August 08, 2024, 05:53:37 pmI understand and this make sense. However, based on such principle, it should be even more efficient if we leave ice and cold water exposed to the open air. If I have to take this principle into account, I would say that insulated ice chest used in such projects are only to release the cold air in a controlled manner allowing in this way a longer ice retention. This when the main goal is to decrease the room temperature and such goal can be achieved (at this point the released cold is reduced just to the minimum to maintain the temperature allowing in this way longer ice retention). If this achievement is not possible (which seems to be very likely), then an ice chest should be useless because at this point would become more efficient to release immediately all the available cold without any insulating layer. Is my deduction correct?

author: Someone
author_rank: Super Contributor
timestamp: August 08, 2024, 11:26:07 pm
content: Quote from: YouCanDoIt on August 08, 2024, 10:52:37 pmYou're adding layers of complexity for very little value. Want to feel cold? Put cold object in contact with your body (in the areas with high blood flow like the neck).https://www.safepak.com.au/brands/body-cooler-cobber/cnt-neck-tie.htmlThe sort of system you are suggesting is approaching the cost and complexity of just getting a portable air conditioner, and piping it via the window.

author: Someone
author_rank: Super Contributor
timestamp: August 08, 2024, 11:35:12 pm
content: Quote from: YouCanDoIt on August 08, 2024, 11:23:40 pmThese are not yes/no questions, they havenuance(complications).There is a thought/calculate/measure experiment at high school level, roughly "does adding milk to a coffee now or just before 10 min keep the coffee warmer at the 10min point?". You need to walk back and start with understanding that sort of problem before taking it to a larger and more complex system. But even then its not actually that complex and electronic tools can readily "solve" the equations:https://doi.org/10.3390/en13112899"Simplified Building Thermal Model Development and Parameters Evaluation Using a Stochastic Approach"

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 09, 2024, 12:55:04 am
content: Quote from: Siwastaja on August 08, 2024, 06:10:05 pmThanks for making this clear!So...ON ICE + WATER COMBO, NO ADDITIVES AT ALL!Quote from: Siwastaja on August 08, 2024, 06:19:25 pmSiwastaja, from what you described your project and the results you got I would consider this much more than a success.At this point you're only left with the annoyance to swap boxes. In my case I believe I should be free from this (I hope) or at least I will not have to do it frequently.If I have understood well, the cooler was designed with an integrated freezer, right? Once cubes are ready you open some sort of lid, release them to the water and start the cooling process.I initially thought to something like that. Vevor, the same brand of my ice chest, produce a30L portable refrigerator(price is twice!). My idea was to avoid ice blocks, just an air intake and a blower motor to push the cold air outside, but when things seems too much easier they usually don't work. I had to realize how many things can go wrong with a refrigerator like that with two big holes and a constant flux of hot air inside of it. It would have been useful only for ice preparation and given that most of the times I need to use the cooler at home, it would have been a waste of money with an already existing freezer that does the same job.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 09, 2024, 01:46:42 am
content: Quote from: ebastler on August 08, 2024, 07:21:04 pmMany thanks, ebastler! Your calculations are very useful to get an idea although I'm not sure I got it in full, mostly because it's hard for me the energetic point of view.if I have understood well, a 1 kg Ice pack will take 333 kJ to convert the underline water to around -15 (the related energy or what else), but the process does not end here. There are additional 120 kJ to convert the water from below zero to a suitable temperature for the system (15C or less, but still above zero).So, an AC, with 9000 kJ can keep the room cool for 1 hour. With the ice cooler and 4 kg of ice only for 12 minutes which means 20 Kg of ice is needed to get 1 hour like the AC.If this is correct, then you're right, it's incredible and very hard to believe.IanB posted similar calculationshere.Around 10Kg to drop by 5C and for a short while (may be 1 hour like your calculations?).So, if I'm not wrong, cooling down a room in an acceptable way can work, but depends from many conditions: room size, how many degrees we have to drop, how many kilograms of ice we can supply to each cycle, whether is a dry or humid climate and the list continue...What I don't understand is how that guy was able to drop by 10-20C with just, maybe, a couple of kilos and for around 4 hours.Let see once I have all the stuff ready what I can achieve! Very hard to estimate now (and to be honest, I would prefer to not know in advance). 50% humidity is not a good starting point, but I think is not even too much.

author: IanB
author_rank: Super Contributor
timestamp: August 09, 2024, 02:42:26 am
content: Quote from: YouCanDoIt on August 09, 2024, 01:46:42 amRemember, getting a stream of air to come out of a nozzle at 5°C is easy. That is not the same as cooling a whole room down to 5°C (which is basically impossible). Even a proper A/C unit would fail to do that, or even get anywhere close.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 09, 2024, 03:47:14 am
content: Quote from: IanB on August 08, 2024, 07:50:12 pmYou're right and ebastlerexplained the reasonsin an excellent way. There are still advantages, but not the ones we all want!Quote from: IanB on August 08, 2024, 07:50:12 pmThis is what I wrote when I published the DIY dehumidifier videohere.Design is very similar to mine, only difference is that condensation occurs in the radiator rather then in the copper coils.So, if I manage to keep water a couple of degrees above zero, my system will become also a dehumidifier.Quote from: IanB on August 08, 2024, 07:50:12 pmYes, the lie was just an ironical hypothesis. I have just responded to ebastler about its own calculations which basically seems to match the ones you previously posted.Now that I understand your calculations, a mistaken is the only thing I can think of. A 2-3 degree drop as I originally suspected seems to be more reasonable, but 4 hours seems too much. However, as you see in the screenshot I posted he was firm on stating it was 10-20 degrees and even more. And the question he responded was clear.I invited him to join the discussion because I'm very curious to solve this mistery and also because he have experience on the field while here many people tend to write their own conclusions based on what says science. This is for sure the first point to check, but science can't calculate all the variables and parameters that there are in the real world.Quote from: IanB on August 08, 2024, 07:50:12 pmThanks Ian, thanks to this explanation, your and ebastler calculations things are much more clear. From what I have understood, cooling down a whole roomis not impossible at all, but there are so many favorable conditions required (I just mentioned a couple ones) that it makes the achievementnearly impossible.After all, if I manage to cool down a small area (ex: the desk area) for an acceptable time I could consider myself more than satisfied.Quote from: IanB on August 09, 2024, 02:42:26 amThis is a very good point to always keep in mind. I saw that most people (me included) do the mistake to think that if they manage to get 20C from the nozzle, it will be just a matter of time before the whole room drops to 20C. It is easy to fall into such mistake because seems obvious.Quote from: IanB on August 08, 2024, 07:50:12 pmI totally agree and I was going to ask people to slow down discussion.There is really nothing more to say and could be frustrating for people to read the whole discussion. The best thing to do is to put the discussion in stand-by or at least slow it down (it has become very hard for me to respond all) and continue as soon as I have a prototype up and running.This will be the most interesting and exciting part!I think it should be a matter of a week or more before I have all the parts in my hands.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 09, 2024, 05:29:29 am
content: Quote from: ebastler on August 08, 2024, 09:38:51 pmIt has taken time, but I think I got it now! And there is no way to reduce the required energy whatever mechanism I invent.Quote from: ebastler on August 08, 2024, 09:38:51 pmI totally agree! Problem is that life is short and there are too many things to learn. Understanding thermodynamics is not exactly on my priority list. Since the day I was born, this is the first time where understanding thermodynamics would have been useful (and I strongly suspect the last time for the rest of my life).Quote from: ebastler on August 08, 2024, 09:38:51 pmI am surprised about this. I always believed to have at least some minimum intuition, but if an expert in this matter says I don't, then I really must take this seriously and find a way to correct my lacks.Quote from: ebastler on August 08, 2024, 09:38:51 pmThe incapability to extract the relevant information from the posts is something serious and unlike the understanding of thermodynamics, the correction of this behaviour is on top of my priority list. If you can gently tell me where I exhibited this behavior I would really appreciate. In this way I can work to improve my behavior and create less annoyances to people.I would not call mine reluctance. It is more of the need to debate when I feel I have arguments and, most of all, such arguments are not faced by the interlocutor, but when this happens and I have no more arguments, I'm the first one to close the discussion. You can see a concrete sample on the response I got from Siwastaja for which I have given 5 stars. With just a couple of rows he demonstrated why some of my ideas does not work.Quote from: ebastler on August 08, 2024, 09:38:51 pmIronically this is exactly what I'm trying to do. Just look at my previous message. I asked people to slow down the discussions and wait that I come back with something up and running. I have done this before I had chance to read your recommendation, but if people continue to write I have to respond. You've probably noticed that I'm not a person who ignores messages. You will have hard times trying to find unanswered questions from my side while I can find plenty ones from the other sides and this certainly contribute to what you call "reluctance and/or incapability to extract the relevant information from posts".Quote from: ebastler on August 08, 2024, 09:38:51 pmFeel free to make a pun about my username, it can't be certainly worse than being considered like a poor unintuitive person unable to extract even the most basic relevant information from posts. And irony is always a good thing!

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 09, 2024, 05:57:34 am
content: Quote from: Someone on August 08, 2024, 11:26:07 pmA temperature controller is probably the easiest and faster implementation of the whole project. It only takes a couple of minutes to prepare the connectors needed by the board. I don't see any complexity in this.Commercial portable air conditioners has been the main reason that forced me to do my own. There are so many things that are wrong with them.Portable air conditioners designed like that does not pipe heat through the window. I mentioned this feature when i was evaluating a peltier module integration (idea aborted long time ago I've been told why was a bad idea).Thanks for the link, I will take your suggestion in consideration if my project ends up to be unsatisfying.Quote from: Someone on August 08, 2024, 11:35:12 pmYou're right, there aren't yes/no questions in such scenarios. Too many variables and complication that may occur. That's why I have ordered just the essential parts to get something up and running. Then, I can see what does not work as expected and possible solutions. As of now I'm just speculating although, as stated from several users, some limitations or issues cannot be worked around in any case.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 09, 2024, 06:51:22 am
content: Quote from: YouCanDoIt on August 08, 2024, 09:18:14 pmYes, there is no way around it. Water is very special medium in this energy storage property, but to utilize it, phase change between solid and liquid is needed. It happening at 0degC is luckily a very good temperature for cooling purposes.QuoteWell yeah, but the usable temperature range is pretty limited anyway. If you run the cooling medium below 0 degC, the condensing moisture from room air freezes and blocks your system. And as I said above, going much above 10degC stops your system from being a dryer, which is pretty necessary in many conditions (unless you live in Sahara desert). So cooling systems generally run their "cool parts" (those that interface with air) between say 5 .. 10 degC. Sure 5deg instead of 10deg allows using somewhat smaller coil / less airflow / less noisy fan.QuoteFreezer size or quality of its insulation ("ice retention") is pretty much irrelevant. Cooling power matters. Freezer's compressor is doing your actual cooling work, you are just using the ice packs as thermal energy storage / transport medium.By all means check the input power rating of your freezer, and I bet it's between 100-300W. Assuming COP of 2, cooling power is thus in range of 200-600W, while usual room air conditioners range between 1500-4000W in cooling power, or so.Because ice works as storage medium, you will be able to exceed that cooling power, but only temporarily: you can freeze a lot of water over 10 days, and then consume it during 1 day, giving you 10x boost in cooling power; that would equal to a real air conditioner! But then you are out of ice for the next 10 days.Or you can find the balance of making the amount of ice the freezer is truly capable of, and keep using it at the same rate. But then the cooling capacity is underwhelming, you can't drop the room temperature/humidity by much. But a little bit yes, and maybe that is enough. And the cooling effect of the cold air hitting the skin is very real of course.QuoteThis is exactly why freezer manual would state the maximum amount of food/liquids you are supposed to freeze per day, it's some quite low value like 0.5 .. 1 kg per 24hrs. The freezer is capable of freezing more, but then other food stuff is in larger risk of spoiling. For your cooling purposes you would significantly exceed this, causing the temperature to rise closer to 0degC.Pre-cooling of course helps, but not that much. As shown above by others, temperature change stores only small part of energy, most is in the phase change. Even if you pre-cool to +1degC, you ease the work of the freezer only a bit; it still has to do most of the work, pushing energy to turn the liquid into solid. But by all means, do pre-cool if possible.

author: tooki
author_rank: Super Contributor
timestamp: August 09, 2024, 01:18:59 pm
content: Quote from: MisterHeadache on August 08, 2024, 02:53:29 pmI’ve only had the most glancing of thermodynamics education in school, but I think that the really unintuitive part of it for people is the amount of energy required for a phase change, and that the temperature is not changed during the phase change. (I think that intuitively, people think that the (static) temperature alone determines the phase. They don’t consider pressure or energy.) That is, it isn’t intuitive at all that a huge amount of energy is required to change 0°C ice to 0°C liquid water, or that a huge amount of energy is needed to change 100°C liquid water to 100°C steam.When I got to the energy for the phase changes of water in school, I already knew that the phase changes required energy, but what surprised me is just how much energy they take. Intuitively, I figured it maybe just needed a little nudge, when in reality, the phase changes require tons more energy than even fairly large changes in temperature (without a phase change).

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 10, 2024, 08:50:26 pm
content: Quote from: Siwastaja on August 09, 2024, 06:51:22 amThis is a good news, or better, it's good that there will be no difference whatever variants of the gel ice packs I chose (apart the build quality). Thatdiscussionabout variants was giving me big headaches.Quote from: Siwastaja on August 09, 2024, 06:51:22 amThanks for the excellent explanation. I should put in bold all of your comments because each one is an excellent source for the design.I understand what you say. So, 5C would be the ideal temperature. Trying to go lower or high than that starts to be risky for the reasons you well explained.Ok, let see what I get once I place the ice packs in the water.Quote from: Siwastaja on August 09, 2024, 06:51:22 amHere is where (I suppose) a temperature controller or a manual switch is helpful by reducing the supplied power. It's on my wish list, but let first get the system up and running before thinking to such kind of enhancements.Quote from: Siwastaja on August 09, 2024, 06:51:22 amUahh...the situation is much complicated than expected.I don't know why the guys from which I posted here their projects (and many other similar projects too) consider size and insulation quality important factors.I've purchased a (relatively cheap) 52QT Vevor box, but there are people using 70QT Coleman extreme boxes. By looking "before" and "after" insulation enhancement, the experiments seem to confirm big improvements:I have no idea on why such conflicting statements. The best I can do is to take all of them into account and expect the worst which in this case is the fact that quality and size of my Vevor is irrelevant. At least, between of all this, I can still have one truth: when I'll use the Vevor as food cooler, its size and excellent ice retention will make a big difference compared to a lower quality product.I will check better later, but my fridge is a Samsung, the Metal Graphite Double Door ones that were on sale, I believe, 5-6 years ago.I understand what you mean. Some other guys gave me some numbers and trying to cool down a whole room is nearly impossible which is fine because my expectation has always been to just cool a reduced area. It's just that I can't resist to a similar challenge.There are so many variables to take into account that it would be very hard trying to understand what to expect. The balance you're talking about is another option for sure.The best I can do is get something up and running and then, once I have some concrete data, see what could be the best next steps.Quote from: Siwastaja on August 09, 2024, 06:51:22 amYou saved me from making something very stupid: put inside the freezer as much ice packs as possible!And given that gel packs shape can be adjusted, I would have probably ended up to fill 90% of the capacity (food included).The guy uses 2 gallon jugs and a 2 ice-packs and reported no issues:If I'm not wrong it should be around 8 liters which means eight 1000ml gel ice bags.I will check later the user manual for the specs you mentioned, but do you think it is safe for any freezer such quantity as a starting point ?So, even if does not help much, pre-cooling is still recommended.I will start with something safe and then will post all the numbers (time to freeze, duration, output temp and many other data). From there we can think to way to optimize everything to get the right balance.ThanksEDIT:Freezer is a Samsung RT29K5030S8, but from theuser manualI can't find anything that mention the maximum amount of food/liquids one should be supposed to freeze per day.However I found interesting features like "Power Freeze" and "Power Fridge" mode. If and how these special modes can help, I prefer to leave the last word to the experts.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 10, 2024, 10:37:55 pm
content: Quote from: tooki on August 09, 2024, 01:18:59 pmtooki, a stupid question, but can this high amount of required energy reduced and/or be partially provided by another source (ex: a solar panel) ?

author: tooki
author_rank: Super Contributor
timestamp: August 10, 2024, 11:12:26 pm
content: Quote from: YouCanDoIt on August 10, 2024, 10:37:55 pmThe amount of energy needed to make your ice is dictated by the laws of physics. It is an inescapable fact.What source of energy you use is up to you, but since you’re using an electrically-powered freezer, then you need electrical power. If you want to install a solar system on your roof, go right ahead — storing cold in the form of ice is one of the few useful ways to store solar electricity (in the summer at least). But to be clear, this means a serious solar installation, not an A4-size panel that can barely charge a USB power bank.

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 11, 2024, 12:22:19 am
content: Quote from: tooki on August 10, 2024, 11:12:26 pmI thought multiple times in the last years if this is the right time to do the transition. Do you think it is better to continue to wait (costs, technology status etc) ? I've been tempted a couple of times from such little panels, but I've always gave up due to the very little usefulness.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 11, 2024, 07:57:38 am
content: You seem to be so enthusiastic in engineering this stuff I don't get it why you consider using ice as an energy transport medium at all. Just hack a freezer to work as a cooler directly. For example, make two holes, build some kind of "maze" inside of it and blow air through it. Or get a good old cheap portable room air conditioner, the kind which sucks indoor air and blows it from a flexible hose, and modify it to perform better e.g. by giving it a closed hot side air loop. I have had excellent results with such mods in the past.

author: IanB
author_rank: Super Contributor
timestamp: August 11, 2024, 08:07:24 am
content: Quote from: Siwastaja on August 11, 2024, 07:57:38 amBecause ice can act as a storage medium. A freezer has a power of a few hundred watts at most, while an air conditioner runs at kilowatts.So a big amount of ice can accumulate a reservoir of cold over a 24 hour period and release it in a much shorter period of an hour or two.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 11, 2024, 10:22:06 am
content: Quote from: IanB on August 11, 2024, 08:07:24 amYeah - storage is great, but it actuallyincreasesthe power requirement:QuoteSure, but cooling for an hour or two is useless for summer time household cooling, as you might want to cool for manymonthsnon-stop or nearly non-stop. Even here in relatively cold country cooling needs are either there for 2-3 weeks straight, or then on a colder summer not at all. Storing enough ice for such long period is impractical.Without storage, you just run 24/7. If you add storage (e.g. to utilize cheaper hours or solar self-use), then you need to deliver the same average power over smaller duty cycle, so need more cooling power, not less.From OP's posts it seems clear his primary purpose doesn't seem to store cheap electricity.

author: joeqsmith
author_rank: Super Contributor
timestamp: August 11, 2024, 03:55:53 pm
content: I was expecting something completely different. Like an actual air conditioner (removing heat).

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 11, 2024, 05:54:00 pm
content: Quote from: Siwastaja on August 11, 2024, 07:57:38 amYou're probably right, but enthusiasm, optimism and a small dose of madness is what is behind DIY.Your idea is very interesting, but when my family will see a pretty new and expensive fridge ruined in this way, do you authorize me to show them where I got this idea when they will try to kill me?Just let me repeat some points for people that came here without having read the message for which I opened the thread, especially when they suggests completely different systems:I have already purchased the ice chest cooler along with some other stuff and before opening this thread (this is something stated from the beginning)The way I designed the project is to have an air cooler and a beverages cooler at the same time and this makes every different system useless (at least with these two goals in mind)Cooling down a whole room is not at all my main target. I have gone through such design with the only intention and expectation to cool a reduced area. Cooling down a whole room (which I know is nearly impossible) is more for the fun I get from the challenge than anything else. I understand that this is what the main discussion is focused on due to the complexity and this may give people the false sense that this is the one target I want to achieve.Thanks

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 11, 2024, 06:00:57 pm
content: Quote from: joeqsmith on August 11, 2024, 03:55:53 pmThere is a diagram at the beginning of the thread where you can clearly see it isn't even without reading, but thanks for letting me know. I will edit the title to make this even more clear!

author: YouCanDoIt
author_rank: Regular Contributor
timestamp: August 11, 2024, 06:29:29 pm
content: Quote from: Siwastaja on August 11, 2024, 10:22:06 amI'm afraid here the thing is subjective and depends from the user conditions. Here I don't have to keep it running 24H and there are intervals where I don't need all the cooling power a similar device can provide. I should also state again that each time I refer to cooling a reduced area (ex: the desk). From now on I will clearly specify when talking about cooling down a whole room (which is not my target, but rather a way to see if I can achieve such goal at least once, just for fun).Regarding the cooling autonomy, I'm afraid this is also subjective, but I promised my self to stop posting the plenty of sources showing different results and from different people which also includes more than satisfying results. I rather prefer to post my own results for which I can respond to all user questions and provide the data they want to know.EDIT:Well, I'm interested to store cheap electricity and I even asked more info on this, but from what I have understood it only make sense with a serious solar panels installation on the roof and I have yet to understand pros and cons.

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2024, 09:57:52 pm
content: Quote from: YouCanDoIt on August 10, 2024, 08:50:26 pmIt’s not in the manual because appliance companies are lazy and write one manual for ALL the different models.But googling the name brings up the product page, and on the “specs” tab, it lists the cooling capacity as3.6kg/24h.That’s literally useless for cooling a room. Or part of a room.

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2024, 09:59:19 pm
content: Quote from: YouCanDoIt on August 11, 2024, 12:22:19 amWhat transition? You can’t transition to 100% solar, because, ya know, nighttime.As for solar in general, watch Dave’s various videos about the topic, and then talk to a professional solar installer to see whether your house is even suited for solar. Not all are.

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2024, 10:03:41 pm
content: Quote from: IanB on August 11, 2024, 08:07:24 amBut that’s not what OP believes. They mistakenly think their household freezer can make enough ice daily to meaningfully chill some are of their room for hours at a time, including overnight.

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2024, 10:08:39 pm
content: Quote from: YouCanDoIt on August 11, 2024, 05:54:00 pmYou realize you can buy a real air conditioner for, like, €300? And that it will perform 100x better than anything based on ice?Also, I don’t think for a second that a fridge modified into an air conditioner could ever be satisfactory for any purpose; the cooling capacity is simply much too small.I totally get the DIY spirit, but I also feel that one should spend their money on DIYing something that is good enough to actually use. Building something based on wishful thinking and hopes and dreams, but which is far removed from reality, is simply a waste of time, money, and materials because in the end, all you’ve done is made a piece of trash that will end up in the bin because it doesn’t do anything useful.

author: Siwastaja
author_rank: Super Contributor
timestamp: August 12, 2024, 07:04:09 am
content: For the cold feeling from cool air directly hitting skin, this kind of contraption is fine, and for that purpose freezer capacity should be OK. Just don't expect significant room temperature drops, any Youtuber who is claiming stuff like that is lying or misunderstanding what is actually happening.I also did this kind of stuff as a kid. I used 1.5-liter plastic soda bottles filled with water, I think I had 8 of them in a box where they fit snuggly, and blew air past the bottles. It was nice until I realized I can't just use our freezer for those eight bottles; freezing two per day seemed a practical limit without serious damage to other foodstuff, so every 4 days I could have a few hours of cooling.

author: ebastler
author_rank: Super Contributor
timestamp: August 12, 2024, 07:13:31 am
content: Quote from: Siwastaja on August 12, 2024, 07:04:09 am+1. "Cooling just a limited area" is fine as long as the "area" is one's chest, rather than a few square meters of a room.To that end, just the air draft from a fan goes a long way, without any active cooling. Lower risk of catching a cold or a stiff neck too...

author: Kurets
author_rank: Regular Contributor
timestamp: August 12, 2024, 09:41:43 am
content: +1 This thread just feels like comedy. But I think the main problem is that OP ends up in a confict of ideas (or sunk costs) state. Even the revamped goal of cooling a limited area does not really work as air in a room mixes quite rapidly (especially with a fan). So this is just a way of trying to avoid accepting that the idea is not good.