Zwo Peltier cooler

[cjdawson]

Hi all.

At SGL 2017, I'm sure some of you will know that I bought myself a lovely new ZWO ASI290MM and had my first go with it.  Achieved everything that I set out to do.  Which was achieve focus.  I did this at F10, and at F6.3.   Almost managed to get focus at F3.3 as well.  (6.3 and 3.3 using focal reducers)

I was surfing the net last night and came across a really nice addition that I could build for my camera....

 

And there's a few modifications in this video too...

 

 

 

 

I love the idea of being able to put some active cooling in place.

So, now that I've had the idea I thought it would be a good idea to document the progress on my contruction of this.   Looks like it will be a clear winner of a project.

[michael.h.f.wilkinson]

Thinking of doing that to my ASI174MM and ASI178MM cameras two. I have a fan and a TEC, but still have to do the build

[cjdawson]

So first things first.  The cooler.    This is the part that will form the core of this project, as it is what will do the cooling.

 

I'm thinking that the description of the cooler in the 2 hour video didn't really suffice.   12v * 3.3A = 39W so they used a 40 watt cooler.   I'm thinking lets upgrade this and use one of these.

 

https://www.amazon.co.uk/dp/B06X8ZZTQG/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1D7CILJETDR19&coliid=I2XQ3FR1GZ6CW9

 

It's a 60W cooler, that will use about 5A.   Sounds like alot of power, but here's the thing, once the camera has cooled to the right temp.  I'll be aiming for about -3°C the peltier will cut out and pulse when cooling is needed.   So it shouldn't use that much power during the session.

With my mains system, I've got plenty of Amps available anyway, so no problems there.

 

As I've been building computers all my life, I've got some Thermal compound 

Something like this for those that don't have it.

https://www.amazon.co.uk/Compound-Performance-Heatsink-Interface-Material/dp/B004D3TUG0/ref=pd_sim_107_1?_encoding=UTF8&psc=1&refRID=T03DFBZGW4A5KC1A1RRG

The idea of this stuff is to improve the thermal transfer.  It's used for CPU's and it's a no brainer to build into this.  It'll help the efficiency.

[cjdawson]

To mount the cooler to the camera, I'm going to follow the nylon screw idea.

https://www.ebay.co.uk/itm/10-Pack-M3-M3-5-M4-M5-M6-NYLON-Plastic-COUNTERSUNK-CSK-Philips-Hd-Screws-Bolts/181423591282?hash=item2a3db04f72:g:rIYAAOSwx-9WyxlP

12mm screws should be big enough.

[cjdawson]

Here's the tempurature control unit that I'm going to use.

http://www.ebay.co.uk/itm/DC-12V-50-110degree-W1209WK-Digital-thermostat-Temperature-Smart-Control-Sensor/262562660839?epid=2133612883&hash=item3d21f441e7:g:VXAAAOSwnQhXot52

10A throughput is more than enough.   I've got some red gel sheet, should be able to cover that blue night.  Hopefully it'll still be readable.

[Dr_Ju_ju]

If you've not seen it, there is an Instructable write up here: https://www.instructables.com/id/Peltier-Cooling-for-ZWO-Astro-Camera/

[cjdawson]

For the heatsink, I think something like this will suffice

https://www.ebay.co.uk/itm/New-AVC-CPU-Quiet-Cooler-Heatsink-For-AMD-FM2-FM1-AM3-AM2-940-939-Desktop-PC/222653584704?hash=item33d7301540:g:w0gAAOSwuLRZxR6O

Bonus that it also comes with a fan.  

 

I'm going to need some screws to so that I can mount the heatsink on the base plate.   Will sort these out later on once I have the heatsink.   That way, will be able to tap a thread and purchard the right screws.   They'll be stainless steel countersunk screws, that will make for a neater finish.   I'll add rubber gromits or washers to act as vibration dampening.

[cjdawson]

5 minutes ago, Dr_Ju_ju said:

If you've not seen it, there is an Instructable write up here: https://www.instructables.com/id/Peltier-Cooling-for-ZWO-Astro-Camera/

That's a useful tip thanks.   I'd not seen it.   I like the idea of the neoprene jacket for the camera.  Think I'll add that to my build.

[cjdawson]

For the jacket, I'll use some of this.

http://www.ebay.co.uk/itm/BLACK-NEOPRENE-PLAIN-SPONGE-FOAM-RUBBER-SHEET-VARIOUS-SIZES-THICKNESSES/261338185781?hash=item3cd8f84035:g:otgAAOSw-itXrJQA

 

6mm tthink and 200mm by 250mm.

[cjdawson]

For the base, I'm going to go a bit overboard and use 3mm aluminum sheet.  This will give a nice block to cool down, and I'll be able to countersink the screws properly.    I already have this (was going to use it for a camera slider, but gave up on that project)

[cjdawson]

Of couse, I'll need some neoprene glue.

http://www.ebay.co.uk/itm/Black-Witch-glue-SCUBA-surfing-Mcnett-wetsuit-Neoprene-repair-seals-surf-dive/161962300338?epid=1853583191&hash=item25b5b493b2:g:Qj0AAOSwFMZWqyup

[Mick J]

Just a thought, when we threw together a Gary Honis for our DSLR years ago (heavy but worked -25) we found the for the peltier to work well we needed to get rid of the heat from the hot side, this allowed the cold side to drop a bit more - obvious I know - but bigger fan and heatsink were our solution.

Gary's suggestion of coolbox parts or (we used) secondhand minifridge had everything we needed.

Great project and will follow your progress.

[cjdawson]

Yep, I like the idea of a bigger heatsink.  Knowing how hot CPU's get, that's why I decided to go for the bigger 80mm fan and heaksink.   From my past experience, AMD chips tended to run hotter than Intel, so going for an AMD based CPU cooler "might" be slightly better.

When I put the cooler together, I'm planning on having the fan suck the air over the heatsink, through the fan blades, then away from the device.  This should help as the hot air will be blown away from the cool side.

Once I've got this thing working, I'll be able to make measurements of how in/efficient it is.

Also from the instructable, I'm considering adding a rubber gasket between the hot and cold side.   This should help to insulate the cold side a little more.

Whilst the theory seems ok, this is something that I'll only find out about for sure once I have it in my hands and can run a test.

[cjdawson]

One last thing that I'm going to do.

Not sure if this is going to be needed, but I like the idea of being able to have some control over the speed of the fan.  So, the simple solution is to add a cpu fan speed controller.

http://www.ebay.co.uk/itm/GELID-Solutions-Variable-Fan-Speed-Control-For-Quiet-CPU-Cooler-Case-Fans/111585998329?epid=649382162&hash=item19fb0b35f9:g:K04AAOSw2s1Uyjp7

[sloz1664]

12 minutes ago, cjdawson said:

One last thing that I'm going to do.

Not sure if this is going to be needed, but I like the idea of being able to have some control over the speed of the fan.  So, the simple solution is to add a cpu fan speed controller.

http://www.ebay.co.uk/itm/GELID-Solutions-Variable-Fan-Speed-Control-For-Quiet-CPU-Cooler-Case-Fans/111585998329?epid=649382162&hash=item19fb0b35f9:g:K04AAOSw2s1Uyjp7

All the cooled CCD astro cameras I have used that have peltier cooling down to -40 degrees have a constant single speed fan, irrelevant of cooling temperatures.

I think adding fan speed isn't needed.

Steve 

[cjdawson]

1 hour ago, sloz1664 said:

All the cooled CCD astro cameras I have used that have peltier cooling down to -40 degrees have a constant single speed fan, irrelevant of cooling temperatures.

I think adding fan speed isn't needed.

Steve 

You are right, it's probably not needed.  The thing is that the module is cheap and simple to plug in.   I'm not sure if it'll end up being in the final build.   Can't hurt to have one to test, if I can optimise the fan speed.

[Stub Mandrel]

Just to add to the advice above, the peltier itself will dissipate about 40 watts, significantly more than it pulls out of the camera.

the more effective your heatsinking and fan the colder the 'hot' side will be and the 'cold' side will always end up a fixed amount below the hot side.

Insulate the camera itself for best results.

For my DSLR I run fan and peltier flat out and haven't tried using temperature control.

[cjdawson]

If I'm understanding things correctly, 40 watts is for a 3 amp cooler.  I've gone for a 5 amp, so that should be 60 watts.   But still, the heat sinking and fan is vital to get right. If Im not happy with plan A.  I'll be able to do tests to upgrade stuff as needed.

[Gina]

3 hours ago, cjdawson said:

So first things first.  The cooler.    This is the part that will form the core of this project, as it is what will do the cooling.

 

I'm thinking that the description of the cooler in the 2 hour video didn't really suffice.   12v * 3.3A = 39W so they used a 40 watt cooler.   I'm thinking lets upgrade this and use one of these.

 

https://www.amazon.co.uk/dp/B06X8ZZTQG/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=1D7CILJETDR19&coliid=I2XQ3FR1GZ6CW9

 

It's a 60W cooler, that will use about 5A.   Sounds like alot of power, but here's the thing, once the camera has cooled to the right temp.  I'll be aiming for about -3°C the peltier will cut out and pulse when cooling is needed.   So it shouldn't use that much power during the session.

With my mains system, I've got plenty of Amps available anyway, so no problems there.

 

As I've been building computers all my life, I've got some Thermal compound 

Something like this for those that don't have it.

https://www.amazon.co.uk/Compound-Performance-Heatsink-Interface-Material/dp/B004D3TUG0/ref=pd_sim_107_1?_encoding=UTF8&psc=1&refRID=T03DFBZGW4A5KC1A1RRG

The idea of this stuff is to improve the thermal transfer.  It's used for CPU's and it's a no brainer to build into this.  It'll help the efficiency.

I've just started reading this thread and having had a fair amount of experience with a number of different Peltier TEC coolers and various cameras.  I've tried the 12706 and they are very inefficient.  I would recommend spending a bit more on a more efficient cooler.  I use a 19W 5v one on my all sky camera with an ASI178MM and it works well.  I'll see if I can find the details.  it was from either Farnell Element 14 or RS Components I forget which.

[cjdawson]

That’s interesting to know about the 12706.    Defiantly interested to know if there’s a better component to use.    I’d prefer to stay in 12v lan£ though, less complicated.

[Gina]

Trouble is generally the lower the power the lower the voltage.  I use a buck converter to reduce my standard 13.8v observatory supply to 5.1v for the Raspberry Pi and cooler.  These are small and very efficient - cheap too   But you could look on those sites I mentioned above for 12v Peltier TECs - expect to pay three or four times the price of the cheap Chinese ones.

[Mick J]

I can remember you stacking Peltier's @Gina did you find a difference in the cooling, I can remember being surprised at the time but now understand it's common practice.

[Gina]

Yes, it does make a difference but you need suitable Peltiers.  ZWO use dual stacked Peltier TECs on their cooled astro cameras.  That's how they achieve 45 degrees Celsius below ambient (or -30 absolute whichever is warmer).

[cjdawson]

I can see this being a very interesting project and I can see myself making a V1 and then modifying several times.     For my first test, I'm still going to stick with the 12706.   It'll work well enough for a proof of concept, and I'll be able to get an idea of how good/bad it is.   Once V1 is working, and if it works well enough, I can see going for dual stacked peltier is an option and achieveable too.   At that point, going for good 5v jobs should do the trick nicely.     Would be great to be able to make my uncooled camera work at -10 or -20.

[cjdawson]

Some of the parts have arrived.   The Peliter, neoprene, glue and the plastic M4 screws.   Checked that the screw fix into the ZWO, 12mm length, looked to be about perfect for this build.

 

Was thinking about the Neoprene sheet over the weekend, and had the thought that I might cover the cold side of the cooler with it as well.  The idea is that the camera and cold place are then encased in neoprene.  This should help to insulate the cold plate from the warmer surrounding air.