Peltier Cooling fan query

[Bobby1970]

1 hour ago, Adam J said:

You need a fan with a magnetic breaing / low noise as if its making lots of noise then its certainly causing vibrations to the sensor.

Adam

It wasn't so noisy until I swapped it around. 

I wonder if it's pulling air through, and around the heatsink find and fixing screws??

Going to try reducing the speed at some point and add temp ctrl. 

 

[Gina]

With fan cooling the air is usually blown onto and through the fins. 

I'm using an ASI178MC in my All Sky Camera which uses an exposure of 60s at night.  It has Peltier TEC cooling with thermal insulation round the camera casing.  The heat from the hot side is removed with water cooling rather than a fan as an ASC is outdoors.  Fan cooling is used for the radiator that cools the water in the observatory, in relatively dry air.  You may think water cooling is OTT but it has a few advantages.  No vibration at the camera, very efficient and as I said, the fan that eventually provides the cooling is in a fairly dry environment. 

For use in an observatory, damp is not a problem and as long as the fan is a low-noise version you should be alright.  You won't get the sensor as cool as with a proper cooled astro camera with a double-stage Peltier TEC arrangement but your setup should definitely help.

[Bobby1970]

Thanks for the info @Gina. 

With my "testing' so far mine seems to run cooler with the fan the opposite way around. ie pulling air from the heatsink out to ambient. 

I am awaiting on a dew heater for the front end to hopefully help with the sensor window fogging. If this all works I will then look at some temp control with the intention of a target of 3-5 degrees. I will then be looking at a quieter fan and/or speed control for the fan and checking for any vibration issues with the image the camera produces. 

I read a little about heatsinks and their jest dissipation ratings. I do wonder if there's a way to avoid using s fan altogether with an appropriate sized heatsink tbh. 

However, I am making all of this up as I go tbh. But it has been good fun so far. 

Ps, glad you are back. 🙂

[Gina]

I don't get any fogging problem even with the sensor at -13C.  Maybe because my thermal insulation is good.  There is a dew heater though which warms the dome and maybe the lens.

[tomato]

I’m not sure of the quality of the fan you are using, some are definitely quieter and smoother in operation then others. 
This is the fan @Tomatobro went for, there have been no issues with this one.

 

 

[Bobby1970]

2 minutes ago, tomato said:

I’m not sure of the quality of the fan you are using, some are definitely quieter and smoother in operation then others. 
This is the fan @Tomatobro went for, there have been no issues with this one.

 

 

Been looking at some so called "silent" fans so it sounds like I have options there. 

I did fire it up this afternoon and pointed the scope at a distant chimney pot. The image seems nice and stable so fingers crossed vibration isn't going to be an issue. 

Away on holiday from Friday so will pick this back up after then. 

[Gina]

I've found Artic fans to be good and quiet.