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Thread: adding TECs to my baseplate, advice needed

  1. #1
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    Default adding TECs to my baseplate, advice needed

    Can anyone who has set up their own TEC cooling under their baseplate (rather than the TECs inside commercial modules) give some ideas or suggestions on this? I would like to have a very conservative amount of TEC cooling for my baseplate so I wouldnt have to worry about the diodes overheating as I upgrade and add more. But I also don't want to have the peltiers so close that they interfere with each others operation from the heat generated by each.

    The peltier cooler I'm familiar with is TEC1-12706. Let me know if a bigger one might be a good idea.
    The TEC is going to be controlled by a dedicated driver: http://www.ebay.com/sch/tomorrowssys...1&_ipg=&_from=

    It will be attached to the baseplate with a heatsink plaster, the a CPU cooler attached under it ( http://www.ebay.com/itm/New-Dual-Fan...gAAOSwT5tWGcul )

    I'm thinking of placing the thermistor inside the most "center" diode mount of each module.


    Base plate thickness is 1cm. I have an older case with 6mm baseplate. I might add a TEC to that one as well when I decide to replace the DPSS modules with diodes.

    Should there be 1 TEC for each module, positioned at the middle of the module?

    There are 4 CPU fans on left and right of the bottom part of the case, one side blowing air in and the other blowing out, I think should take care of the TEC heat.

    Does this all sound good?

  2. #2
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    I was going to suggest the opt TEC unit. Seems a good device but I have not used one. The biggest issue is getting the heat out of the case followed by vibration from the fans. You need to explain more in terms of the heat load to really comment. For example are you sure passive cooling is not enough. Why do you think you need tec cooling? I've seen 10w projectors that use passive cooling. DTR makes 25mm copper heatsinks. That should be enough for most any diode. I've used these z-bolt heatsinks and they are very good. http://www.greenlasermodules.com/index.html Takes any 12mm diode assembly. They are however big. Point is be sure you really need to go to the trouble. Let us know how the opt tec unit works if you get one.

    If you decide to cool say a set of 500mw reds, I would think you would be better off isolating the cooling block from the optics assembly block so you just cool the diodes and not the whole base plate. Will make a lot less need for heat removal as well.

  3. #3
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    For example are you sure passive cooling is not enough. Why do you think you need tec cooling? I've seen 10w projectors that use passive cooling.
    The new high power blues get pretty warm. Diode driver has automatic shutdown feature by measuring the temp of the housing so there's almost no danger of frying the diodes but I wouldn't want some diodes to simply turn off during projection.
    Reds seem fine but I'm thinking of overdriving them like planters does to get the red closer to the blue and green power level.

    If you decide to cool say a set of 500mw reds, I would think you would be better off isolating the cooling block from the optics assembly block so you just cool the diodes and not the whole base plate. Will make a lot less need for heat removal as well.
    Unlike my old DPSS modules where the TEC/heatsink/fan sandwitch is at the top of the module case the modules I'm building can't have the TEC on the top unless I have the optics hanging upside down. I prefer not to go this route as alignment will be a pain. If I have the tec on the bottom of the module then I see two options: either have a heatsink on the bottom with a fan cutout and a cutout on the optical plate to push the hot air down to the first floor where the drivers and PSUs are and eventually out of the case. I see two issues with this design approach, 1) Since there's a heatsink at the bottom of each module, rises are needed for the dichroic mirrors and scanners. Doesn't seem very elegant design approach, 2) cutting holes on my optical plate and 3) optics are not sealed anymore.

    Quote Originally Posted by kecked View Post
    DTR makes 25mm copper heatsinks. That should be enough for most any diode. I've used these z-bolt heatsinks and they are very good. http://www.greenlasermodules.com/index.html Takes any 12mm diode assembly. They are however big.
    Yes exactly, they are big. I think is an issue since I want to knife edge.

    If you decide to cool say a set of 500mw reds, I would think you would be better off isolating the cooling block from the optics assembly block so you just cool the diodes and not the whole base plate. Will make a lot less need for heat removal as well.
    What do you mean by isolating the cooling block? I can prevent heat to transfer by air between the modules, but won't the heat still be transferred via the base plate , unless there's active cooling preventing heat from building up on the optical plate?



    Quote Originally Posted by kecked View Post
    Let us know how the opt tec unit works if you get one.
    I will, but maybe in a month time because I'm taking a vacation.

  4. #4
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    Unless you plan to attempt to cool the entire base plate to below ambient and this is a going to be a big challenge, I would recommend that you use your effort and money to maximize the heat removal from your base plate. Peltier devices are very inefficient and the heat they remove on one side requires so much added heat that gets to the hot side that the heat sink (fins or even the massive base plate itself) can get pretty warm. This opposes your gradient and the cold side temp does not drop very far. This is why TECs are primarily used for low heat load, spot cooling.

    You might want to look into the closed loop, water based CPU coolers that are pretty inexpensive, low vibration and work far better than any simple air heat sink I have ever seen. They are pretty amazing.

  5. #5
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    I'd put the tecs in a way to not cool the whole baseplate, only the diode housings, but I don't see a design choice to achieve that. If each color has a plate of its own, it goes on the baseplate itself. So either the TEC has to be under the big baseplate to cool it which in turn will cool the module plate, or have an aluminum module housing to cool the module from its top, which makes removing heat problematic since its on the optics floor then.
    Every commercial module I've come across claims to use TECs, I don't know where it's placed though. I've seen one which has a TEC on the bottom, in a hole drilled for the TEC, but that will heat up the baseplate which you say is not a good idea.

    I'll check out water cooling, thanks. No experience with them.

  6. #6
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    I quite like the look of that heat pipe cooler you suggested, the only downside is the 80mm fans which make a load of noise.

    If you discover a 120mm version I would quite like the link!

    The corsair H55 cooler that Mr P seems to suggest have 120mm fans that run much quieter however they are twice the price but work really well and have rubber tubing which allows a little more leeway when it comes to positioning the radiator.

    Also he didn't object to the base plate getting hot other than the heat convecting up to the cool plates, so why not just turn the entire projector upside down ........... or if you prefer downside up
    The optics won't mind and you also get access to them from below for adjustment without moving the projector which can be handy.
    Cheers

  7. #7
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    The corsair H55 cooler that Mr P seems to suggest have 120mm fans that run much quieter however they are twice the price but work really well and have rubber tubing which allows a little more leeway when it comes to positioning the radiator.
    I actually use these Corsair coolers. They will even operate down to 9V where they are absolutely quiet and still remove heat extremely well. Be aware that the rubber tubes are pretty short and not very flexible ie about 20cm long and 1.5cm in diameter, but this positioning flexibility can be very helpful. They WILL NOT LEAK.

    why not just turn the entire projector upside down
    This can make alignment and your visualization during layout kinda challenging.

  8. #8
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    ... I have an old medical 20W@652nm-diodelaser somewhere with a pretty big TEC-cooled baseplate - the modulde base sits on two rows of TEC's, 7 in one row, and the TEC's are attached to a big fin-cooler with a fan blowing air through the fins.

    Attached are two images of the module and the TEC's.

    Have plans to use this set for higher powered IR-diodes (up to some hundred Watts @975nm) and see, if the cooling will be enough.

    So greater cooling areas (and powers) with TEC's were common some ten years ago too ...

    Viktor

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  9. #9
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    @ This can make alignment and your visualization during layout kinda challenging.

    We all need something to look up to !

    Cheers

  10. #10
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    1:14

    This is what I had in mind actually.
    Have you changed your mind about this kind of setup, or did I not explain what I intended properly?
    Last edited by Nii; 07-13-2016 at 00:08.

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