Run psu without a fan?

[mousesnob]

Im making a minifridge for my dorm, using scrap parts at my summer job.

 

I'll be powering a 60w peltier element aswell as a fan(s) maybe a pump. I'd like for the fridge to run noiseless so im considering running a standard atx psu without a fan. If not then i'll do a fan swap. The one i have on hand is a coolermaster b500, a fairly low tier psu. 

 

Would a powerdraw of 60-70 watts be fine to handle passively by a psu that is designed to be activley cooled? 

[mariushm]

Consider getting a laptop adapter instead. or xbox power supply or some other console power supply that can do more than 60w 

Some power supplies are efficient enough and have heatsinks big enough that they'll be able to run without fans.

If you don't know, you'll just have to measure it ... get an infrared temperature measurement tool (one of those with laser to point at heatsinks), color the heatsink with some black marker if needed so that the tool is not affected by how shiny the heatsinks are, and measure the heatsinks as your power supply runs outputting 100w for some time (you can get some 12v car/motorbike lamps as a load, they're super cheap)

If you don't have such tool, a multimeter that can measure temperature would work, with a k type probe ... tape it to the heatsink.

 

If the heatsinks stay under 80-90c, the psu should be fine to use without heatsink.

 

 

[manikyath]

keep it 'fan side up' (hole side up?), as long as you dont stress it past a very slight amount (so, 60W on a 500W psu should be fine) it will kick out very little heat.

 

having that said, are you planning to also passively cool the hot side of the peltier? because i'll tell you ahead of time that that's not gonna work as well as you think. you need that thing to be real cold to actually get a decent amount of cold in the fridge.

 

any noise you may have of a PSU fan running idle is gonna be meaningless next to what's needed to keep a 60W peltier at room temp.

[Guest]

1 hour ago, mousesnob said:

Im making a minifridge for my dorm, using scrap parts at my summer job.

 

I'll be powering a 60w peltier element aswell as a fan(s) maybe a pump. I'd like for the fridge to run noiseless so im considering running a standard atx psu without a fan. If not then i'll do a fan swap. The one i have on hand is a coolermaster b500, a fairly low tier psu. 

 

Would a powerdraw of 60-70 watts be fine to handle passively by a psu that is designed to be activley cooled? 

Just use something made to be fanless like a power brick.  Smaller and won't blow up.

 

And cooling the hot side of a Peltier isn't quite "noiseless".  Usually people use CPU coolers on 60+W coolers.

[mousesnob]

2 hours ago, mariushm said:

Consider getting a laptop adapter instead. or xbox power supply or some other console power supply that can do more than 60w 

Some power supplies are efficient enough and have heatsinks big enough that they'll be able to run without fans.

If you don't know, you'll just have to measure it ... get an infrared temperature measurement tool (one of those with laser to point at heatsinks), color the heatsink with some black marker if needed so that the tool is not affected by how shiny the heatsinks are, and measure the heatsinks as your power supply runs outputting 100w for some time (you can get some 12v car/motorbike lamps as a load, they're super cheap)

If you don't have such tool, a multimeter that can measure temperature would work, with a k type probe ... tape it to the heatsink.

 

If the heatsinks stay under 80-90c, the psu should be fine to use without heatsink.

 

 

I agree that a laptop charger would probably be a better idea. I might wait out for one. That would be noiseless aswell, and would give me alot more space in the chassis of the fridge.

47 minutes ago, jonnyGURU said:

And cooling the hot side of a Peltier isn't quite "noiseless".  Usually people use CPU coolers on 60+W coolers.

1 hour ago, manikyath said:

keep it 'fan side up' (hole side up?), as long as you dont stress it past a very slight amount (so, 60W on a 500W psu should be fine) it will kick out very little heat.

 

having that said, are you planning to also passively cool the hot side of the peltier? because i'll tell you ahead of time that that's not gonna work as well as you think. you need that thing to be real cold to actually get a decent amount of cold in the fridge.

 

any noise you may have of a PSU fan running idle is gonna be meaningless next to what's needed to keep a 60W peltier at room temp.

No i know peltiers can be quite tricky. I do not expect to run it passive. However the element ran fine with a 240mm aio with two random fans running at 5 volts. It also handled a 20 watt peltier stacked ontop of the 60w running fans at 7 volts, granted at 20c ambient (which i did just for fun literally playing with garbage). Might be false advertising calling it noiseless but its certianly quiter running a compressor fridge. 

 

I think a laptop charger would be much smarter to use thank you guys for the tip. Im not sure which one is a more potenital fire hazzard lol.

[manikyath]

3 minutes ago, mousesnob said:

I agree that a laptop charger would probably be a better idea. I might wait out for one. That would be noiseless aswell, and would give me alot more space in the chassis of the fridge.

No i know peltiers can be quite tricky. I do not expect to run it passive. However the element ran fine with a 240mm aio with two random fans running at 5 volts. It also handled a 20 watt peltier stacked ontop of the 60w running fans at 7 volts, granted at 20c ambient (which i did just for fun literally playing with garbage). Might be false advertising calling it noiseless but its certianly quiter running a compressor fridge. 

 

I think a laptop charger would be much smarter to use thank you guys for the tip. Im not sure which one is a more potenital fire hazzard lol.

the thing is.. you already have fans.. so you already have forced airflow... so there's no sense to say that the psu then cant have forced airflow for noise reasons.

[mousesnob]

1 minute ago, manikyath said:

the thing is.. you already have fans.. so you already have forced airflow... so there's no sense to say that the psu then cant have forced airflow for noise reasons.

All the psus that have come and ive tried have been fairly noisy, 2011-2013 stuff. They seem to always be the loudest component, rpm seems to be constant for the most part. Had i put it in my main build it would be louder than my pc under full load. Im definatley not proposing passive only. It just seems simpler to just remove the noisemaking component if it dosent impact the purpouse. 

[Guest]

6 minutes ago, mousesnob said:

All the psus that have come and ive tried have been fairly noisy, 2011-2013 stuff. They seem to always be the loudest component, rpm seems to be constant for the most part. Had i put it in my main build it would be louder than my pc under full load. Im definatley not proposing passive only. It just seems simpler to just remove the noisemaking component if it dosent impact the purpouse. 

Then you're looking at some pretty cheap PSUs.  At that low of a load, the fan should only spin about 600 RPM.  Typically, that's going to be about 15dBA or less.  A lot of fans also have a fanless mode at that low of a load.  So if you KNOW you're not going to push the PSU over 20% of it's capability, you could rip the fan out altogether.... or just leave it there "just in case" something goes wrong.

[mousesnob]

15 minutes ago, jonnyGURU said:

Then you're looking at some pretty cheap PSUs.  At that low of a load, the fan should only spin about 600 RPM.  Typically, that's going to be about 15dBA or less.  A lot of fans also have a fanless mode at that low of a load.  So if you KNOW you're not going to push the PSU over 20% of it's capability, you could rip the fan out altogether.... or just leave it there "just in case" something goes wrong.

Im working with literal garbage ;). The rm850x 2018 in pc main is inaudible to me. But my budget for this fridge is as close to 0 usd as i can get. Going by that logic, is it safe to assume that a higher wattage rated psu would have a more robust cooling setup, which in turn would make it more suited to passive cooling? I think i have a cx750m green label also, which has power but is loud.

 

And for laptop charger idea, the one that come in are generally 65w. I assume that would be too close for comfort given the load?

[Guest]

4 hours ago, mousesnob said:

Im working with literal garbage ;). The rm850x 2018 in pc main is inaudible to me. But my budget for this fridge is as close to 0 usd as i can get. Going by that logic, is it safe to assume that a higher wattage rated psu would have a more robust cooling setup, which in turn would make it more suited to passive cooling? I think i have a cx750m green label also, which has power but is loud.

 

And for laptop charger idea, the one that come in are generally 65w. I assume that would be too close for comfort given the load?

Yes.. a larger PSU would be less susceptible to heat at low loads than a lower wattage unit.  If you look at the fanless units from Seasonic and Superflower (as an example... not saying you should buy one), they're literally selling you a higher wattage PSU like a 1000W, but as a 650W and ripping the fan out.    That's why they're so expensive.