[foodhackingbase] [incubator] Re: update on the experimental incubator testing

Thu Jun 12 02:15:53 CEST 2014

So if I simplify it, you are basically saying that the heat generation 
by the ventilators should not be the issue, right? I wonder what is the 
issue, Lars what do you think? You are the one with functioning cooling 
prototype :-)

Sincerely FAA

On 2014-06-11 21:38, Marcel van der Peijl wrote:
> I use two big aluminum heatsinks 25x10cm, 5cm high, with two 90W
> peltiers inbetween, with lots of grey heatsink paste. Initially I used
> a plate of 3mm MDF to isolate the two heatsinks from eachother, but
> that started soaking the oil from the paste and the paste got dry and
> brittle. I initially used 2 7cm fans on each heatsink. I managed to
> only cool 4C down. After a rebuild I made the inbetween plate from HPL
> (high pressure laminate). And put 9cm fans on. The fans use 2W each. I
> can not imagine the 4W on the inside of the box is responsible for the
> fact that it slightly heats now. I did try switching on only one
> peltier - this resulted in constant temperature. The outer heatsink is
> definitively hot.
> 
> The two heatsinks and inbetween plate are kept together by 4 nylon
> screws now. Before I used 3mm metal rods, but I feared that was the
> heat leak.
> 
> I ordered some 60W peltiers and will let you know if that changes
> stuff. It just feels to me the outer heatsink is too hot and should be
> cooled more by fans, and this is the problem we face. I will try
> getting a big room fan (220V) and force cooling the outer heatsink to
> see if that makes a difference.
> 
> Marcel
> 
> 
> -----Original Message----- From: Frantisek Algoldor Apfelbeck
> Sent: Wednesday, June 11, 2014 3:03 AM
> To: experimental incubator mailing list
> Cc: Sven Uckermann ; Lars Möller ; Philipp ; Food Hacking Base mailing
> list ; Arnd
> Subject: [incubator] Re: [foodhackingbase] update on the experimental
> incubator testing
> 
> Hi Sven and all,
> thanks for the thought. Below is link to the picture of the
> heating/cooling unit set up
> 
> https://foodhackingbase.org/wiki/File:Experimental_incubator_mamut_tamna_2_1_cool_box_cooling_brain_wires_800_600_faa08062014.jpg
> 
> it is the outer part but the internal system is exactly the same. More
> info on the prototype is here
> 
> https://foodhackingbase.org/wiki/Experimental_Incubator/2.1_mamut_tamna
> 
> As you can see there is quite pretty decent heating sink there
> (connected by thermalpaste) which is not getting too hot or cold so the
> distribution of the heat/cold enhanced by the fan is I think quite
> reasonable. However your note made me realized what is most likely the
> actual problem which I should see straight away. It looks like that the
> fan which we use to "distribute" the "cold" produced by peltier is 
> doing
> it's job but because it is basically small electric engine it is of
> course producing heat. So the final drop in temperature is 
> corresponding
> to the cold produced by the peltier minus the heat produced by the fan.
> It looks like that the production of the heat by the fan is quite
> substantial therefore the drop in temperature is just small. I've
> received word from Marcel who installed even stronger system - more
> powerful peltiers and it looks like that instead of cooling he is
> actually heating, is it so Marcel? That may be confirming the idea 
> which
> I mentioned above.
> 
> What I wonder is if we can somehow minimize the heat production by the
> fan which seems to me we need to distribute the cold from the peltier,
> or do we? We need to cool the hot side otherwise it burns but can we
> leave the cold side alone? Would the dissipation of cold be sufficient?
> Or shall we use some another system of air circulation or just less
> powerful fan?
> 
> Thanks for any thoughts this one is quite a challenge I think.
> 
> Sincerely,
> 
> Frantisek
> 
> 
> On 2014-06-10 15:37, Sven Uckermann wrote:
>> Hi,
>> the problem with cooling and heating is that the stuff inside (aka
>> your cultures etc) are often water based and as such an great material
>> for taking heat .. but the air as such is a good insulator so getting
>> rid of the heat of the peltier while cooling seems to be your problem
>> ... you might want to add some thermal mass (copper or such) to the
>> "outside" of your peltier .. so it can cool more .. if both sides of
>> the peltier are the same temperature this things dosn't work to great.
>> 
>> Greetings Sven
>> 
>> 2014-06-07 15:06 GMT+02:00 Frantisek Algoldor Apfelbeck
>> <algoldor at foodhackingbase.org>:
>> 
>>> Hi to all,
>>> I've uploaded graphs of the latest Marcel's and my testing of the
>>> experimental incubator:
>>> 
>>> 
>> https://foodhackingbase.org/wiki/Experimental_Incubator/2.1_mamut_tamna
>>> [1]
>>> 
>>> I will play with them more later on at the moment proper legends are
>>> missing and the scales of all graphs are not same which may make
>>> understanding of what is the performance bit hard. Also I need to
>>> add detailed description of the hardware like volume of the
>>> chambers, power of the pelties etc.
>>> 
>>> Especially Marcel's experiment shows the fine heating potential
>>> hitting over 70C, still the cooling is not doing too well. My
>>> heating results are satisfactory hitting around 50C for culturing
>>> many fermented products which I and we here are into, cooling is
>>> definitely not. I still do not know how to switch polarity of the
>>> peltier so the cooling/heating would be done automatically by
>>> program. I need to buy good h-bridge (ideas?) or make one or use
>>> some set of relays (how to do that?). I'm looking forward for
>>> comments!
>>> 
>>> I wonder if Lars could think about what may be the issue with the
>>> cooling because the Warpzone prototype is doing much better, going
>>> down to around 8C at over 25C outer temperature, right?
>>> 
>>> Many thanks for any info, I will be working on this in the next few
>>> days, I just cut my hand so no field work for a while and soon I
>>> will be able to type again properly :-)
>>> 
>>> Sincerely,
>>> 
>>> --
>>> Frantisek Algoldor Apfelbeck
>>> 
>>> biotechnologist&kvasir and hacker
>>> 
>>> http://www.frantisekapfelbeck.org [2]
>>> 
>>> "There is no way to peace, peace is the way." Mohandas Karamchand
>>> Gandhi
>>> 
>>> Disclaimer - there are other people who have access to this email
>>> account, please be aware of that it is part of the design. For
>>> "highly private communication" use algoldor at yahoo.com
>>> _______________________________________________
>>> foodhackingbase mailing list
>>> foodhackingbase at lists.hackerspaces.org
>>> http://lists.hackerspaces.org/mailman/listinfo/foodhackingbase [3]
>> 
>> 
>> 
>> Links:
>> ------
>> [1] 
>> https://foodhackingbase.org/wiki/Experimental_Incubator/2.1_mamut_tamna
>> [2] http://www.frantisekapfelbeck.org/
>> [3] http://lists.hackerspaces.org/mailman/listinfo/foodhackingbase

-- 
Frantisek Algoldor Apfelbeck

biotechnologist&kvasir and hacker

http://www.frantisekapfelbeck.org

"There is no way to peace, peace is the way." Mohandas Karamchand Gandhi

Disclaimer - there are other people who have access to this email 
account, please be aware of that it is part of the design. For "highly 
private communication" use algoldor at yahoo.com