Posted: Mon Aug 12, 2002 2:32 pm
Hello everyone,
<br>
<br>i've read a few things about running a PSU fanless, I've been fiddling with my Enermax 330W PSU recently, and i've just read Mike's article "Running a PSU without a fan?" with great interest. I've also made a silent PC for myself, and a site about this subject. And i studied physics and work in the field of heating, which also helps me understand this subject.
<br>
<br>All this put toghether, here's my opinion :
<br>
<br>First : convection means "Hot air rises up". So if one wants to cool fanless, it's essential to provide a path for the hot air, from the bottom to the top : something ressembling a wide enough and vertical tube (like a chimney indeed!).
<br>So i think that when Mike puts the PSU upside, with the cover ON, he's getting closer... The "tube" is vertical, but it's rather obstucted at one end : you'd need to cut the back of the PSU open (the side that is opposite to the 80 mm fan).
<br>Mounting such a PSU in this way (vertically) on a normal casing means making an opening on the TOP of the casing, contrary to the usual opening at the back. Of course it also means making wide enough openings at the bottom of the case, for proper air intake.
<br>
<br>Secondly : to cool by convection, one needs big heatsinks, and a limited amount of heat.
<br>
<br>- limited amount of heat : that means a PSU with a small power, a high efficiency, and not much load. Enermax are just too powerfull to be good candidates. Their aluminum heatsinks are not big enough either.
<br>- big heatsink(s) : we need to look into the PSU, and maybe tweak or change the original heatsink...
<br>
<br>Among the currently available PSU with reasonnable price, I would try the Q-tech 300W : you rank it an 8, and say it has big heatsink.
<br>A small PSU (90W, 140 or 150W maximum) like those found in (small) barebones is also very interesting. These barebones, with a low heat output-CPU is a very promising system to run totally fanless (but it would need to modify the case and PSU quite a lot).
<br>
<br>By the way, and bout small loads, I think the C3 is rather a false good solution, as downclocked Celerons or PIII are more powerfull CPUs than the C3, and the heat output must be in the same range. After studying your recommandations and the famous "electrical specifications of processors", i think that the 1,13 PIII-S downclocked to 100 Mhz FSB and downvolted is a very good candidate for a fanless yet rather computing-powerfull PC.
<br>
<br><!-- BBCode Start --><B>null</B><!-- BBCode End --><!-- BBCode Start --><B>To summarise all this : making a PC work fanless involves major tweating of the case and PSU. One can not just take the fan out of a normal PSU and hope this will work, as you proved it with your article. </B><!-- BBCode End -->
<br>
<br>Personaly i don't have the time and money to build a fanless PC, although i find it very challenging and interesting.
<br>
<br>At the time being, after making my silent PC as described in my site, i'll put both original fans of the Enermax PSU on 5V, with a 100 ohms rheostat (bought today) in series : at about 4V, they'll be silent and still cool the PSU. This is a similar approach as Mike's Panaflo on 5V, but it's even cheaper : about 2 dollars for the rheostat and it's button... These original fans are not bad, they're just spinning too fast!
<br>
<br>I don't have much time to take part in the forum at the time being, as i am already involded in a few french forums and it is time consuming...
<br>
<br>If you want to take a look at my own website on silent PCs (in french) : <!-- BBCode auto-link start --><a href="hhtp://hmeandsilentpc.free.fr" target="_blank">hhtp://hmeandsilentpc.free.fr</a><!-- BBCode auto-link end -->
<br>It's not as good and complete as this one, but it's helpfull to those french people who dont read english...
<br>SRPC will be added in my links in the next update.
<br>
<br>_________________
<br>my own site about silent pc (in french) :
<br><!-- BBCode auto-link start --><a href="http://hmeandsilentpc.free.fr" target="_blank">http://hmeandsilentpc.free.fr</a><!-- BBCode auto-link end -->
<br>
<br>i've read a few things about running a PSU fanless, I've been fiddling with my Enermax 330W PSU recently, and i've just read Mike's article "Running a PSU without a fan?" with great interest. I've also made a silent PC for myself, and a site about this subject. And i studied physics and work in the field of heating, which also helps me understand this subject.
<br>
<br>All this put toghether, here's my opinion :
<br>
<br>First : convection means "Hot air rises up". So if one wants to cool fanless, it's essential to provide a path for the hot air, from the bottom to the top : something ressembling a wide enough and vertical tube (like a chimney indeed!).
<br>So i think that when Mike puts the PSU upside, with the cover ON, he's getting closer... The "tube" is vertical, but it's rather obstucted at one end : you'd need to cut the back of the PSU open (the side that is opposite to the 80 mm fan).
<br>Mounting such a PSU in this way (vertically) on a normal casing means making an opening on the TOP of the casing, contrary to the usual opening at the back. Of course it also means making wide enough openings at the bottom of the case, for proper air intake.
<br>
<br>Secondly : to cool by convection, one needs big heatsinks, and a limited amount of heat.
<br>
<br>- limited amount of heat : that means a PSU with a small power, a high efficiency, and not much load. Enermax are just too powerfull to be good candidates. Their aluminum heatsinks are not big enough either.
<br>- big heatsink(s) : we need to look into the PSU, and maybe tweak or change the original heatsink...
<br>
<br>Among the currently available PSU with reasonnable price, I would try the Q-tech 300W : you rank it an 8, and say it has big heatsink.
<br>A small PSU (90W, 140 or 150W maximum) like those found in (small) barebones is also very interesting. These barebones, with a low heat output-CPU is a very promising system to run totally fanless (but it would need to modify the case and PSU quite a lot).
<br>
<br>By the way, and bout small loads, I think the C3 is rather a false good solution, as downclocked Celerons or PIII are more powerfull CPUs than the C3, and the heat output must be in the same range. After studying your recommandations and the famous "electrical specifications of processors", i think that the 1,13 PIII-S downclocked to 100 Mhz FSB and downvolted is a very good candidate for a fanless yet rather computing-powerfull PC.
<br>
<br><!-- BBCode Start --><B>null</B><!-- BBCode End --><!-- BBCode Start --><B>To summarise all this : making a PC work fanless involves major tweating of the case and PSU. One can not just take the fan out of a normal PSU and hope this will work, as you proved it with your article. </B><!-- BBCode End -->
<br>
<br>Personaly i don't have the time and money to build a fanless PC, although i find it very challenging and interesting.
<br>
<br>At the time being, after making my silent PC as described in my site, i'll put both original fans of the Enermax PSU on 5V, with a 100 ohms rheostat (bought today) in series : at about 4V, they'll be silent and still cool the PSU. This is a similar approach as Mike's Panaflo on 5V, but it's even cheaper : about 2 dollars for the rheostat and it's button... These original fans are not bad, they're just spinning too fast!
<br>
<br>I don't have much time to take part in the forum at the time being, as i am already involded in a few french forums and it is time consuming...
<br>
<br>If you want to take a look at my own website on silent PCs (in french) : <!-- BBCode auto-link start --><a href="hhtp://hmeandsilentpc.free.fr" target="_blank">hhtp://hmeandsilentpc.free.fr</a><!-- BBCode auto-link end -->
<br>It's not as good and complete as this one, but it's helpfull to those french people who dont read english...
<br>SRPC will be added in my links in the next update.
<br>
<br>_________________
<br>my own site about silent pc (in french) :
<br><!-- BBCode auto-link start --><a href="http://hmeandsilentpc.free.fr" target="_blank">http://hmeandsilentpc.free.fr</a><!-- BBCode auto-link end -->