Peltier Cooling fan query

[Bobby1970]

I have just ordered some bits to attempt to make my own cooler for my 178MC camera.

One query i have though, should the fan suck the warm air away from the heatsink, or should it be sucking ambient air onto/across the heatsink?

Thanks in advance

[Davey-T]

Never made one but have the Peltier stuck to a finned aluminium heatsink with thermal paste then the fan sucking air away from it maybe.

Dave

[Bobby1970]

1 minute ago, Davey-T said:

Never made one but have the Peltier stuck to a finned aluminium heatsink with thermal paste then the fan sucking air away from it maybe.

Dave

That was my thinking tbh. 

 

Hopefully someone who has made one can confirm. 🙂

[Xplode]

It's usually best to blow the cold air at the object that needs to be cooled, this is how, this is how 99% of all computers are setup

[Bobby1970]

19 minutes ago, Xplode said:

It's usually best to blow the cold air at the object that needs to be cooled, this is how, this is how 99% of all computers are setup

So that would be sucking the ambient air onto and across the heatsink???

 

 

[Xplode]

I'd rather say blowing air onto the heatsink

[fozzybear]

@Gina is your expert on these maybe she can shed some light on best practices usage and which one's work best

[vlaiv]

There is absolutely no difference.

This is old question asked by computer enthusiasts that over clocked their computers, many tests were done and results are the same - it does not matter.

Consensus is that push / pull configuration is the best   - as it uses two fans - one to push ambient air into radiator and another one to remove - thus creating steady flow.

[Xplode]

1 minute ago, vlaiv said:

There is absolutely no difference.

This is old question asked by computer enthusiasts that over clocked their computers, many tests were done and results are the same - it does not matter.

Consensus is that push / pull configuration is the best   - as it uses two fans - one to push ambient air into radiator and another one to remove - thus creating steady flow.

There is a difference, but how much depends on the situation.
Remember pushing air directs it pretty well, but pulling air through a heatsink it will just pull where it's least resistance.
You can see a test done on a graphics card there
https://youtu.be/IJmE13sG9PI?t=719

In general it's best to have the fan push onto the heatsink rather than pull.

 

[Tomatobro]

I have modified a few. Used high spec processor cooling fans.

Latest versions have temperature control to stop icing on the sensor lens

[vlaiv]

4 minutes ago, Xplode said:

Remember pushing air directs it pretty well, but pulling air through a heatsink it will just pull where it's least resistance.

Not sure that I follow the argument, here is counter argument - air will be pushed in direction of least pressure.

 

[Tomatobro]

I cannot remember if the fans I used push or pull, perhaps if Tomato reads this he can confirm.

Sharpcap will give you the sensor temperature as it seems that ZWO output the temperature data even on basic cameras. One thing to look out for is that the fan and heat sink restricts access to the camera body so check where you will grab to screw and unscrew the camera. If you grab the fan the whole heat sink will turn on the camera body.

ZWO do an add on circular heater to stop fogging of the sensor lens but I gave up on these and just controlled the temperature body to just above freezing. From memory the sensor temperature runs about 4 degrees higher than the camera body.

Just looked up the spec and the fan blows down onto the heat sink

Edited October 5, 2020 by Tomatobro
spelling + New info

[tomato]

Somebody asked this question before, I can confirm the air flows from the camera to the heat sink.

 

[gajjer]

Just now, vlaiv said:

Not sure that I follow the argument, here is counter argument - air will be pushed in direction of least pressure.

Not sure that is true. When a hair drier blowing, it blows in a concentrated stream of air. If you reversed the motor, I don't think it would suck in the same concentrated flow.

My gut tells me that blowing air through the fins is better but with such close proximity of the fan to the heatsink, I don't think there would be much difference.

cheers

gaj

[david_taurus83]

7 minutes ago, gajjer said:

Not sure that is true. When a hair drier blowing, it blows in a concentrated stream of air. If you reversed the motor, I don't think it would suck in the same concentrated flow.

 

It does such it in, from the back of the hair drier.

[martin_h]

My QHY9 draws warm air from the heatsink to the outside air

[wulfrun]

Standard practice is that a fan should blow air onto a heatsink, never suck from it. Blowing causes turbulent flow off the fan blades. Not the same application but the principle is the same as explained here: https://sound-au.com/heatsinks.htm#s18

Edited October 5, 2020 by wulfrun
typo

[Tomatobro]

 

The QHY website has a picture of the imaging module fan and heat sink for the QHY9.   Air is drawn through the fan and blown into the heat sink which follows the conventional setup for pelter cooling.

The answer to which is best is......well it all depends

All fans the input energy transfer into the outflow so the air leaving the fan is warmer than the input. Yes I know it feels colder but that is due to the evaporation from sweat glands which aluminium has not.

If the fan, its positioning and the heat sink are carefully matched then the air will be at a slightly higher pressure within the heat sink so there are more molecules to collect the heat and the turbulence imparted by the fan ensures more of these molecules impinge on the heat sink surface so taking away the heat.

If however the fan and heat sink are mismatched then the back pressure will be higher and will stall the fans airflow thus reducing the throughput.

 

 

[wulfrun]

1 hour ago, david_taurus83 said:

It does such it in, from the back of the hair drier.

But they invariably blow over the heating element.

[gajjer]

Just now, david_taurus83 said:

It does such it in, from the back of the hair drier.

I didn't say it didn't suck in. I was trying to say it wouldn't suck in a concentrated stream. It will draw air over a wider area.

cheers

gaj

[Bobby1970]

Thanks for all of the replies. I hope I haven't opened a can of worms here lol

Seems as though pulling ambient air into the heatsink is the best way to go. 

 

 

[tomato]

48 minutes ago, Bobby1970 said:

Thanks for all of the replies. I hope I haven't opened a can of worms here lol

Seems as though pulling ambient air into the heatsink is the best way to go. 

 

 

Don’t worry, this is tame stuff compared to the discussions on focal reducers.☺️

[martin_h]

On 05/10/2020 at 19:43, Tomatobro said:

 

The QHY website has a picture of the imaging module fan and heat sink for the QHY9.   Air is drawn through the fan and blown into the heat sink which follows the conventional setup for pelter cooling.

The answer to which is best is......well it all depends

 

Very interesting thread, my QHY9 defiantly blows away from the heatsink.....quality control!!!! Anyway I have just flipped the fan around and will bang off some darks tonight.

[Bobby1970]

I am still waiting on a Peltier cooler. Got most of the bits now. But the pletier arrived with one of the wires hanging off. So it's been returned. 

Hope to have something cobbled together at the weekend. 

I'm not expecting it to perform as a cooled camera would. But from the you tube videos it would seem a reasonable improvement in terms of noise in images can be had. Fingers crossed. 

Edited October 8, 2020 by Bobby1970

[Bobby1970]

So. The replacement peltier arrived today.

I have literally just cobbled this together for some testing. 

 

Anyway I left it running for 10-15mins. Temp down to 3.5 degrees. So pretty good I think. 

However, the sensor window fogged up :-(. And there was some moisture on outside of the camera.camera 😞

So, my next query is, what can I do to stop the foggiing up and the moisture build up ? 

Really pleased at the performance of the cooler itself. Just another couple of issues to fix now. 😡

 

Wonder if I can make one of these fit:-

https://www.firstlightoptics.com/zwo-accessories/zwo-anti-dew-heater-strip-for-asi-cooled-cameras.html

 

 

Edited October 9, 2020 by Bobby1970
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