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| Thread ID: 66196 | 2006-02-14 20:40:00 | Adding cooling | The_End_Of_Reality (334) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 430333 | 2006-02-15 06:16:00 | you need to look at the design more. mainly the flow of the fans and location. i'm suprised you getting the case that hot. things to check...are the fans pointing the right way? are the in/ou airflow matching? removing fan grill (use wire grills instead) ups the fan airflow hugely without increasing noise. also look at what fas your useing. is the case air inlet big enough. a lot of cases its to small and need to be enlarged to handle such large air flows. | tweak'e (69) | ||
| 430334 | 2006-02-15 06:16:00 | Terry, haven't you heard? The laws of thermodynamics have been repealed. They don't comply with the Treaty of Waitangi, and certainly don't fit with the Knowledge economy and market ideology. I notice that the laws of thermodynamics, especially the first law, go a bit haywire around Waitangi Day, must be something to do with the temperature, doesn't seem to happen so much in the winter! |
Terry Porritt (14) | ||
| 430335 | 2006-02-15 08:21:00 | tweak'e, all fans are the right way, I have checked them. What do you mean by 'are the in/out airflow matching?' I can not remove or replace the fan grills. I think the inlets are a little too small, but drilling them out will be a mission because they are behind the mounting rack :annoyed: |
The_End_Of_Reality (334) | ||
| 430336 | 2006-02-15 08:53:00 | don't think so small ;) check to see if cfm in matchs cfm out. grills, cut them out with a dremmel or other small saw. to get at the front ones pull the front of the case off. i recommend pulling the whole pc apart before doing any cutting. |
tweak'e (69) | ||
| 430337 | 2006-02-15 09:08:00 | how do I do that? I know I have 5 fans blowing in and 3 fans sucking out, that is all I know, I don't know the CFM of the fans in there. True, I guess that would work |
The_End_Of_Reality (334) | ||
| 430338 | 2006-02-15 09:21:00 | need to know what the cfm rating of each fan is, then guess at how much flow you loose. check out this pic (homepages.paradise.net.nz) | tweak'e (69) | ||
| 430339 | 2006-02-15 09:42:00 | Ok, here (www.dse.co.nz) is the 4 fans I put in the front, they are 25CFM, and the other 3 came with the case, but they are bound to be somewhere very close, so there is 125CFM going in, in theory, and 75CFM going out, these are 'perfect conditions' I would estemate I get 10CFM in from the front fans each, 20CFM from the side, that totals 60CFM. and 45CFM out, though I am ROUGHLY GUESSING the flow, this does not sound right for the in/out fan ratio. LOL to that, that must be powerful, or in its day anyway, depending on age :p |
The_End_Of_Reality (334) | ||
| 430340 | 2006-02-15 10:45:00 | Hi I was checking out cooling info a week or so ago and came across this interesting site www.xoxide.com It showed the differences between positive and negative pressure in your pc case and how to achieve either option. Hope this is helpful Have a great day Meg |
meg_h_nz (6960) | ||
| 430341 | 2006-02-15 20:45:00 | Thanks for that Meg, it was very interesting, now I know that I want more air going out than in :) | The_End_Of_Reality (334) | ||
| 430342 | 2006-02-15 21:20:00 | Thanks for that Meg, it was very interesting, now I know that I want more air going out than in :) Ahem... that article has a lot of old cobblers in it :) Pseudo-science and mumbo jumbo. Ignore what is says and follow tweak'es advice, you wont do any better than that This is why some of it is cobblers: There is no "vacuum" in the case, if there was it would probably 'implode' :) Except for considerations of dust, which is debateable, then the optimum static pressure in the case should be as close to atmospheric as possible. This is because either a raised pressure or a reduced pressure means the fans are working against a pressure head in either blowing or sucking. Then the flow rate will be reduced, look at the pressure -flow curves for the high speed Delta fans. You will also notice from the curves, that when one of those fans is completely obstructed so that flow is zero, the pressure rise (or reduction) is less than 2" water gauge. So much for "vacuuum". So when the fans are not working against a pressure head (or having to suck through a restriction) the flow will be maximised. The aim of case fans is to try to keep the inside temperature as close to outside room temperature as possible, and in particular to keep the air temperature at cpu and chip fan intakes as close to that as possible so as to minimise chip temperaure rise. Now one way is to have a very large flow through the case, another is to 'intelligently' duct or direct a somewhat lesser air flow to the chip fan intakes. However, a reasonable flow is still required to entrain and remove the heated air from the chips. Talk of dead zones is also mumbo jumbo, whether the static pressure is above or below ambient by a fraction of an inch of water will not affect the flow pattern inside the case. 'Dead zones' in the corners of the case will exist anyway and cause no problem If the temperature inside the case is not far above room temperature, then case material is immaterial :) Because the case is not used as the primary means of cooling. It is far more important to go for a case design that has good provision for large fans, and non of this silly perforated steel grill nonsense. Tweak'e is quite right. Get rid of perforated steel. First of all, the flow area is reduced by about 1/4 to 1/3 as compared to a full open diameter, and secondly each little hole is a sharp edged orifice having a discharge coefficient of around 0.5. This means the fan is working against considerable flow resistance, and flow rate could be halved compared to using a wire grill, or nothing at all. Just follow tweak'e and you wont go wrong :thumbs: |
Terry Porritt (14) | ||
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