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Case Pressure Explained - Positive vs Neutral vs Negative

2014-07-25
hey what's up guys Jase $0.02 here and if you remember just the other day I did a video talking about static pressure versus air flow when it comes to fans and naturally you guys asked hey do more videos please about how to do case fans and things like that so naturally the next video in this little series was a no-brainer we're going to talk about gun or optics no actually that's next week's video so today we're going to talk about case pressure positive pressure neutral pressure and negative pressure and what it all means to the cooling of your systems so yeah today we're going to try and bring you a case flow 101 when it comes to air cooling water cooling and what it means to have different types of pressures in your case now for this video today I'm using the cooler master cosmos se it we're gonna actually be doing a full review on this in a future video but it's going to be for demonstration purposes today so what we have in front of us right here is a case or an enclosure or chassis some various things that they are referred to as but this is where all the parts of your computer go in if you guys didn't know that you might want to go back a little bit and start more of the basics but this is a computer case now the chassis serves two purposes it is to a house all of your computer parts and B it is to create a cooling environment now by creating this cooling environment it also gives you control over the air flow and that's very very important not only other things on your motherboard like the heatsink and the V RMS and things that need to be cooled there are lots of parts in your system that require airflow to transfer the heat out of the system now the major heating dynamic that's taking place inside of your system here is radiation and where the heat is actually radiated into the atmosphere and how that system heat is removed from the chassis now the three different types of chassis environments that you can create here are a positive environment and by that I mean it tells your computer it's doing a good job and to keep going and it's very very supportive and positive there is a neutral environment or their basic basically everything is like hey you know you're doing your best but keep trying harder and this is a negative environment where it basically just tells you you're a piece of grill I probably took the analogies a little too far so let's go ahead and start with positive pressure positive pressure basically means nothing more than you have more intake than you do exhaust that means you have more air entering the case and the fans exhausting it or able to move so what happens is the air has to find a way out that's one of those things with physics we just can't change that so the air pretty much finds a way out and the way it finds those ways out our vents in the bottom vents right here in the PCI Express slots those most of those cases have vents now you have these little rubber grommets for water cooling you have the expansion slots over here on the side you have vents in the top I mean pretty much cases these days are very very ventilated now you also have neutral pressure which means you have an equal amount of air coming in as you do going out so you don't actually create any pressure positive or negative now negative as you may have guessed by this point it's where you have more air being exhausted that is being taken in so if scientists were right and every action has an opposite and equal reaction that means if we have more air being exhausted that means all of our events become intakes the exhaust fans have to pull the air from somewhere and if the intake fans are not feeding the case that means that air is making its way into all of these vents now why do we care about this as PC builders well guys it really comes down to two things one temperature control if you can get more cool air entering the case especially in a water-cooled system you're going to have a much better cooling environment we have more cool air entering and more cool air means more density for the cool air to be able to absorb the heat or actually the heat to transfer to the cold air remember it goes from hot to cold and then that air being exhausted through the vents and the fans and that other thing being dust control so if you AskMe dust control is probably the most important reason at least in my opinion why anyone should care about positive neutral or negative warning guys I'm about to bust a myth right now we're going to keep it really really real positive pressure only reduces dust if all of your intake fans are filtered let me repeat that positive pressure only reduces dust if all of your intake fans are filtered if you don't have filters on your fans the dust is just going to come right in through the fan you're not going to actually have any dust control whatsoever but with that said it actually becomes very difficult to create a positive pressure environment when you have intake fan filters because they tend to be pretty damn restrictive now let's talk about ways that you can actually create a positive pressure environment positive pressure is what I recommend it's by having higher rpm or higher static pressure fans in the front then you do in the exhaust remember guys more air in less air out Eagles positive pressure all of the ventilations no longer become little suck magnets for bringing dust into your system because most of the time that's where dust is going to make its way in I cannot think of a single scenario where negative pressure is actually desired in fact negative pressure tends to pull air in from the sides and it actually creates a situation where if you're running water cooling or a radiator because of the added resistance the air is going to find the travel of least resistance which is going to be through the open exhaust fans now air is going to travel through your radiator but trust me positive pressure is where you want to be neutral pressure is actually very very difficult to achieve on cases these days because as you can see the cooler master cosmos se has a whole lot of restriction on the frontier in fact we do have two 120 millimeter intake fans but you can see the top half of this fan is being blocked by this hot-swap drive right here or cover I guess I should say and right behind those as you can see is the drive cages immediately so these fans are going to be very unlikely to be able to have the air reach all the way through to the exhaust fans in a case like this if you were air cooling I would actually recommend that you take the top fans and instead of having these being exhaust maybe turn them into an intake so it's blowing it's blowing cold air right onto your heatsink and then you have your exhaust fan exhausting as much air as it can in this case it would create a positive pressure environment now guys it may sound like I threw an awful lot of information at you hopefully you're not more confused so let me just go ahead and summarize positive pressure means you have more air in than you do exhausting and all of the excess air has to have a place to go it will exhaust through all of the vents through pressure rather than the fan moving the air so you have air being exhausted by the fan as well as air being pushed out through the vents negative pressure is where you have more exhausting fans than you do air coming in so the air that's being exhausted literally gets pulled in through all of the ventilation and unfortunately that pulls in a lot of dust with it as well neutral pressure it's very very unlikely you're ever going to be dealing with neutral pressure in fact a perfect example of neutral pressure would be this right here the side case is open you have neutral pressure which means all the air on the cooling components like the heat sinks like all of these like the passive heat sinks down on motherboards and Southbridge Northbridge and AMD things like that are actually not getting cold because there's no air moving over them so opening the side of the the case like this would actually create a neutral environment which is not good either you have to have some sort of airflow so guys I hope this has given you some clarification I mean if it didn't I sincerely apologize maybe I'll try and do another future video where I actually show maybe through smoke how the air moves I just I don't have a smoke machine I don't smoke I'm not gonna blow into it and dry ice I don't know I don't how to do that anybody have any suggestions on how to get smoke in here and show how things actually move yeah so anyway guys there you go positive neutral and negative pressure explained by J's to sense aim for positive it's a good thing it's called positive for a reason let me get on out of here guys follow on Twitter if you have any questions the fundraiser is doing really really good we've actually unlocked white a lot of giveaways I'm gonna be doing here on the channel and if 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