Re: [DIYbio] DIY Refrigerated Centrifuge

I used Pelitier coolers for fuel systems, not life science wet lab. the Peltier 3 layer stack was pinned to a manifold which ran perhaps at a duty cycle of 50% with maybe 0.3 G of vibration continuously. As in nominally expected to run perhaps 3 years without maintenance.. This chilled Methane maybe down 45 C. Note Pelitier cooling versus expended power is very quirky.  Unlike compression chilling, its weirdly non-linear, when lightly loaded versus cell capacity, its efficient and worsens as it achieves higher loading... ex a multi layer stack will do a better job at fixed dissipation then a less or singular stack... just because the one considered is a area of a postage stamp, the same thermodynamics apply...

I see some alum or perhaps some better allow test tube holders and assoc charging stations. Creating a center of gravity for a load is by definition pretty simple.. 

Yet, actually creating anything repeatability usable is a non trivial process of trial and error. Obviously, the best way to achieve the goal a few times is go someplace else with the 'right' equipment and ... the goal is achieved.

But *if* it is easy to visualize the requirement is ongoing, especially if other temperature management requirements are achieved; ( handling simplified, lower RMS of unwanted delta T deviations, etc. ) It might be worth considering.

Managing temperature is a very very common industry requirement. Omage has a catalog the weight of a hand brick and a half with thousands of doo dads to do these things...

https://www.omega.ca/en/

50 ml seems a convenient mass to consider chilling with a rechargeable aka 'battery' one of fixture... 

ther unwanted wiggle in the centrifuge is Omega V^2 so again the question of the reasonableness or not of the notion involves extreme specification of the goals, delta T's and G's, how long the new temp must be maintained, etc....

Also, if for instance the device is rechargable on a USB 5 V port probably it can squirt back the temperature encountered. That is, instead of being an improvisation, such a device can be a normalizing aspect of utility in the science of the process itself, possibly...

Regards,

Daniel B. Kolis

On Mon, Oct 31, 2022 at 12:44 PM John Griessen <jo...@industromatic.com> wrote:

On 10/23/22 10:26, Dan Kolis wrote:
> Ive had complete success with Peltier fixtures. this $5 semi moves 8 W and has a 8 by 15 mm face...

What was it like balancing the weight and attaching wires so they don't move on a centrifuge rotor?
The 9V battery seems large for centrifuges we usually think of.  Are you using an old school centrifuge for 50 ml vials?

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