It depends how big the air gap is. There would of course be an optimum. I haven't seen how this $80 PCR works yet. But it strikes me that if it's just the plastic tubes in direct contact with the heatsink then that that really is a dumb idea.
Heatsinks would be pretty bad at directly removing heat from plastic tubes in this way. However they are very good at removing heat from air, or water or other fluids.
What I described is essentially a CPU heatsink - which of course do work by allowing sufficient airflow around the heatsink. In general these work very well and offer quite accurate levels of temperature control. So why not sit a small water bath (or air bath - whichever you prefer and whatever tests prove will work more efficiently) in the middle of a heatsink carved from a similar piece of aluminium to the above $80 design and have fans blowing down (or across) the heatsink to remove the heat? I don't think it matters so much if the water (or air) inside the bath itself is moving or not, just so long as there is enough of it (although still a relatively small volume) to allow rapid heat transfer to the heatsink?
Inside the water bath sitting in the middle of the heatsink, you would of course need a small (possibly coiled) heating element to heat up the water (or air) when required. You would also need a temperature sensor and a means of controlling the temperature at precise intervals. The only point of having a relatively small volume of water (or air) is to be able to cool and heat this as rapidly as possible.
I am not describing anything revolutionary. This is as I said pretty much how CPU heatsinks and fans work, as I'm sure you know. I assumed this was how the $80 PCR worked anyway?
On Wednesday, 4 June 2014 10:43:32 UTC+1, John Griessen wrote:
-- Heatsinks would be pretty bad at directly removing heat from plastic tubes in this way. However they are very good at removing heat from air, or water or other fluids.
What I described is essentially a CPU heatsink - which of course do work by allowing sufficient airflow around the heatsink. In general these work very well and offer quite accurate levels of temperature control. So why not sit a small water bath (or air bath - whichever you prefer and whatever tests prove will work more efficiently) in the middle of a heatsink carved from a similar piece of aluminium to the above $80 design and have fans blowing down (or across) the heatsink to remove the heat? I don't think it matters so much if the water (or air) inside the bath itself is moving or not, just so long as there is enough of it (although still a relatively small volume) to allow rapid heat transfer to the heatsink?
Inside the water bath sitting in the middle of the heatsink, you would of course need a small (possibly coiled) heating element to heat up the water (or air) when required. You would also need a temperature sensor and a means of controlling the temperature at precise intervals. The only point of having a relatively small volume of water (or air) is to be able to cool and heat this as rapidly as possible.
I am not describing anything revolutionary. This is as I said pretty much how CPU heatsinks and fans work, as I'm sure you know. I assumed this was how the $80 PCR worked anyway?
On Wednesday, 4 June 2014 10:43:32 UTC+1, John Griessen wrote:
On 06/03/2014 05:41 PM, Jebus Jones wrote:
> would not some form of heatblock arrangement (like a CPU heatsink) on a CPU be used (with a suitable gap to contain a small volume
> of air) with a heat/radiator source (again like a CPU) with a fan arrangement blowing over the heatsink in preprogrammed cycles to
> produce this rapid cycling effect?
The air gap you describe would not be moving, thus it would be a high barrier to heat flow -- an insulator.
-- You received this message because you are subscribed to the Google Groups DIYbio group. To post to this group, send email to diybio@googlegroups.com. To unsubscribe from this group, send email to diybio+unsubscribe@googlegroups.com. For more options, visit this group at https://groups.google.com/d/forum/diybio?hl=en
Learn more at www.diybio.org
---
You received this message because you are subscribed to the Google Groups "DIYbio" group.
To unsubscribe from this group and stop receiving emails from it, send an email to diybio+unsubscribe@googlegroups.com.
To post to this group, send email to diybio@googlegroups.com.
Visit this group at http://groups.google.com/group/diybio.
To view this discussion on the web visit https://groups.google.com/d/msgid/diybio/eb591b73-fcd4-45b4-98ce-84682d135638%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
0 comments:
Post a Comment