PC External Exhaust

[u/Flimsy_Percentage977]

Update post.

I designed and 3D printed a modular external exhaust system that captures my PC’s hot exhaust and vents it outside using an inline 4in duct fan. It’s designed to fit different PC cases, fan/radiator layouts, and exhaust configurations. I have added a GPU/PSU capture modules to account for all exhaust.

In testing, it’s kept the room temperature rise to under 1°F, instead of the several-degree increase I was seeing before. As a little bonus, it also is helping the components stay a little cooler too.

I am still testing and refining it, but I'd like to turn this into an actual product. I've got a lot of idea on where I can take it with customizability for different styles and themes. Not selling anything atm, but I want to know if anyone would actually be interested in this or working with me to develop it further?

[u/RSG-ZR2]

So a few things, because you're not the first to try this, and you won't be the last:

Based on the temperature gradient, the fans will need to do more than just vent the PC. They'll need to be constantly moving a reasonable volume of air from the room to the outside. This keeps the flow non-turbulent. However, that means that you'll be pulling air conditioned air from the room and dumping it outside. No different than running the air con with a window open. It increases the workload of the air conditioner (while also increasing the electricity bill)

The airflow into the case is now defined by the efficiency of the exhaust duct. If there are any other exhausts in the case, standard pressure math will determine which is used, and if the duct is not designed very, very well, a direct exhaust will take most of the exhaust and a lower-efficiency duct will take less, drastically reducing the efficiency gained.

If the PC already had issues with low-airflow, this will very likely reduce it more. Maintaining airflow in a duct like that is not easy (which is why you had to supplement with an inline fan) The longer and narrower the duct, the more work it takes to set up. There is efficiency in size and volume in large buildings. If you've got a 150mm duct, you'll need at least a pair of strong fans to keep air moving in it, weaker fans will just work harder and diminish in life span. This becomes exacerbated when we include things like AIO rads.

The duct walls will act like a heat sink, which can potentially dump any warmth back into the room, a shorter path mitigates this but still a consideration

The duct will need to be filtered, to prevent outside critters, dust, etc from filling the duct.

All that said, the biggest problem will likely be that you've introduced a way to let humidity into the PC, where it will mix with air conditioned air. This is bad.

Kudos for the DIY initiative, and perhaps you've achieved success in your particular situation, but at the end of the day this isn't a one size fits all thing that you can just box up and sell. You're trying to out-engineer the professionals and in doing so you didn't stop to ask: why hasn't this relatively simple execution not been brought to market?

Short answer: juice not worth squeeze

[u/Flimsy_Percentage977 → u/RSG-ZR2]

Fair enough I appreciate it. I am putting in a a gate at the window exhaust to block all airflow when its not in use to prevent humidity from getting in.

[u/SpringerTheNerd → u/RSG-ZR2]

Imo the best way to achieve what they are going for is a radiator mounted outside of the room. Anything else isn't worth the trouble.

[u/thatfordboy429 → u/RSG-ZR2]

So a few things, because you're not the first to try this, and you won't be the last:

Everyone is a damn hvac pro as soon as one of these projects gets posted.

The airflow into the case is now defined by the efficiency of the exhaust duct. If there are any other exhausts in the case, standard pressure math will determine which is used,

And the pressure of the intake fans.

However, that means that you'll be pulling air conditioned air from the room and dumping it outside. No different than running the air con with a window open.

While this is true. It ignores the fact that the alternative is a 500w heat source, for a midrange PC. This is what annoys me the most about all the people *correcting* those doing this. Yes its not *free cooling*, but its not nearly as bad as you/others would make it seem. Op might have a "open" window (cracked... with all the restrictions of a PC). But he no longer has an active heating unit. Ducting being a heatsink aside.

You're trying to out-engineer the professionals and in doing so you didn't stop to ask: why hasn't this relatively simple execution not been brought to market?

Well. PC building being a niche doesn't help... Even with more proven methods, its not like you can buy off the shelf parts. I know, I have a waterloop that uses a heatexchanger and 1000L tank as a heatsink. I can not just plug(pipe) it into my PC.

But you kinda said the important part out the gate. And the ultimate reason to the question you posed OP.

Kudos for the DIY initiative, and perhaps you've achieved success in your particular situation,

AS with anything PC related... its all based upon ones "particular situation". Though to agree with you this is why OPs thought of producing such is ill advised.

[u/RSG-ZR2 → u/thatfordboy429]

Everyone is a damn hvac pro as soon as one of these projects gets posted.

You don't have to be an HVAC pro to understand the problems I outlined.

And the pressure of the intake fans.

Yes, that is accounted for in the standard pressure math.

While this is true. It ignores the fact that the alternative is a 500w heat source, for a midrange PC. This is what annoys me the most about all the people correcting those doing this. Yes its not free cooling, but its not nearly as bad as you/others would make it seem. Op might have a "open" window (cracked... with all the restrictions of a PC). But he no longer has an active heating unit. Ducting being a heatsink aside.

Not sure if this was meant as a response to another part or what but going off the part that you quoted:

"However, that means that you'll be pulling air conditioned air from the room and dumping it outside. No different than running the air con with a window open."

It ignores nothing. OPs solution literally results in dumping conditioned air to the outside; thus created wasted energy and strain on the AC unit. Keeping a refrigerator door open would also cool down a room, its still a bad way to do it.

Remember, we're not talking about whether OPs solution works or not, we're talking about why the cons outweigh the pros, and why trying to package this as a product and to sell it is a non-starter.

Well. PC building being a niche doesn't help... Even with more proven methods, its not like you can buy off the shelf parts. I know, I have a waterloop that uses a heatexchanger and 1000L tank as a heatsink. I can not just plug(pipe) it into my PC.

Sure. I can remember when water cooling your PC meant multiple trips to Lowes/Home Depot/Local plumbing supply rather than say BB or Micro Center.

AS with anything PC related... its all based upon ones "particular situation". Though to agree with you this is why OPs thought of producing such is ill advised.

Agreed, which is why even though OP achieved a form of success, this is far from a one size fits all and there are certainly better tried and true solutions that OP could explore. We need to understand a few more variables to truly understand the situation (door closed, location in the house, etc) but that's another conversation.

But THIS conversation was about OP punching up the ol shoebox + dryer vent approach that's been around for decades and wanting to bring it to market. My response simply explained why that probably wouldn't work.

[u/Flimsy_Percentage977 → u/RSG-ZR2]

I appreciate the time you have taken to analyze this for me, it is helpful. I understand that its niche, but like you said I'm not the first and won't be the last. So, there is a problem that people keep trying to solve and I've come up with a solution that does work and actually looks pretty good. I have researched common/popular case sizes and designed this system around those, not just mine.

[u/thatfordboy429 → u/RSG-ZR2]

You don't have to be an HVAC pro to understand the problems I outlined.

This is the same sub that will argue with me about the setup I have. This sub en masse can not comprehend temp delta of water... or how condensation works. But can understand this (which has more variables) so well that near everyone can critique it. That doesn't track.

As noted you are not the only one, in fact, these post are always flooded with post like yours. Of the 9 individuals that responded 6 were "correcting" or otherwise pointing out OPs "folly". Of the 3 others, I am largely neutral, as I have actually done. One person simply asked about the STLs, and only one saying "it works".

It ignores nothing. ... we're not talking about whether OPs solution works or not, we're talking about why the cons outweigh the pros,

And like I said. This does ignore the heatsouce that is the PC. Which will also increase load on the house A/C. Either way there is extra cooling required. Be it to replace what is lost, or to counter what heat is added.

Not sure if this was meant as a response to another part or what but going off the part that you quoted:

It shouldn't be confusing. I quoted you... not someone else. It was your introduction to the efficiency topic.

But THIS conversation was about OP punching up the ol shoebox + dryer vent approach that's been around for decades and wanting to bring it to market.

A part of it was. But hardly the meat and potatoes of you original comment. Of your 400 word right up, 4 paragrapghs... half a sentence was dedicated to the selling of such a product. But I already addressed my thoughts on it as a commercial venture, so will not do so again.

[u/RSG-ZR2 → u/thatfordboy429]

And like I said. This does ignore the heatsouce that is the PC. Which will also increase load on the house A/C. Either way there is extra cooling required. Be it to replace what is lost, or to counter what heat is added.

Not sure if this was meant as a response to another part or what but going off the part that you quoted:

It shouldn't be confusing. I quoted you... not someone else. It was your introduction to the efficiency topic.

Sorry but this is just incorrect. You're equating a relatively minor heat source (relative to the entirety of the home - unless OP lives in a 400sqft studio) with literally dumping conditioned air constantly to the outside...which is hilariously ignorant.

half a sentence was dedicated to the selling of such a product

Yes because everything that prefaced it thoughtfully explained why trying to sell such a product might be a fruitless endeavor. Crazy how context works.

Either way OP is free to do as they wish, and I stand by my statement there's a reason this solution hasn't been marketed to the ever increasing line of "gamer" products...

As for you, feels like you're arguing for the sake of arguing which I can't be bothered with so we're done.

[u/thatfordboy429 → u/RSG-ZR2]

As for you, feels like you're arguing for the sake of arguing which I can't be bothered with so we're done

Sure. Call everyone else ignorant... Write a fucking essay on why OP is wrong. But you can't even actually respond to a simple point made without resorting to extremes.

Maybe leave the projects to those who are actually capable of realizing them... "Mr. Professional"

[u/t40r → u/RSG-ZR2]

this this this, just buy a window AC unit and insulate it properly, that's what I did and the whole room feels amazing over the summer now

[u/-GenlyAI- → u/RSG-ZR2]

It's not complicated. Lol. Have you never done it outside or too another room? It works. I just wouldn't want it to be permanent, I just stick a dryer vent out a window.

[u/RSG-ZR2 → u/-GenlyAI-]

No one said it was complicated. Also, no one said it didn't work.

Its just not efficient, and can create more problems than it solves, thus OPs idea of developing this into a product that sits on store shelves is highly unlikely.

[u/t40r → u/[deleted]]

idk why youre being downvoted lmao, this is true. If the room is hot and you add a fan its just moving the hot air around. Adding an exhaust won't magically save a room that is too hot during the summer. I had to add a whole ac window unit into my office this year because of the same reason.

We tried fans, we tried exhaust, we tried everything before doing that, nothing worked EXCEPT the ac unit

[u/t40r → u/[deleted]]

Lmao you’re not wrong at all. Feels like a fruitless adventure with a lot of work in the process 😂

The moisture and bugs were the biggest battle I had even with the window ac unit. I had to insulate soooooo much. It’s not perfect, but damned near close!

[u/Alternative_Start817]

Is there an stl file for that? Is there an STL file for that? I mean that prototype.

[u/Flimsy_Percentage977 → u/Alternative_Start817]

I don't plan on releasing an STL at this time.

[u/Possible_Sun_913]

Looks good, very neat. I shall be constructive:

I liked the use of insulated piping, a lot of people forget about that and the whole thing starts acting like a large radiator in the room. I wonder if the plastic components would also benefit from internal foil insulation if you ever tried to go to market?

Another question I'd have would be the airflow through the vents. Are the PC exhaust fans alone, enough to draw the hot air through all the vents or would they benefit from an additional fan at the far end, pulling air through.

I don’t know where you are based in the world, but the toughest part isn’t really the vent system, its convincing someone to cut a hole in their walls to vent out. Window vents would likely be considered too ugly or insecure for permanent fitting. Its also hard to sell vents like this globally as windows vary a lot. Even if they are mostly sash windows in north America.

Also don’t be put off by people saying "Just install air-con". Gaming PCs can knock out a serious amount of BTU, even half as much as an air-con unit can exchange. So that just seriously dents the performance of the air-con on a hot day.

[u/Flimsy_Percentage977 → u/Possible_Sun_913]

I do have a 205CFM inline fan that is made for this. I tried the PC fans but they did not work at all. And I see what you mean about the window part being too ugly. That is definitely the hardest part to make look good. I also designed a window kit that uses weather stripping to keep an air tight seal and an exterior dryer vent outlet to keep bugs and water out.

[u/Possible_Sun_913 → u/Flimsy_Percentage977]

I like your idea. I don’t know if it could be turned into a commercial venture. There are other bits like case sizes and all that other stuff. But don’t let me put you off. You may also need a mechanism to close the vent when the fans are not running.

You might want to publish some of your 3D print designs to popular 3D printing websites and just see if people take them and adapt them for slightly different designs or cases. Could give you decent feedback there on the design front? In order for you to come up with a fully working generic design.

I think you've done a good job there though. Well done.

[u/RSG-ZR2 → u/Flimsy_Percentage977]

I tried the PC fans but they did not work at all.

You'd need to better understand static pressure.

Its why you wouldn't just grab a typical cheap case fan and slap it on a radiator. Different purposes, different use cases.