Thermoelectric Cooler Peltier & Bed output

[CNCModeller]

Hi All,
After getting my laser operational again I'm trying to minimise it's footprint and am thinking of replacing my external cooler wit an internal one based on PC water cooling system components (as per my Wanhao D4s), and possibly integrate a Thermoelectric Cooler array. In the summer the coolant in the loop used to get fairly warm and that affected the cutting performance significantly.

My question is can I use the bed heater output, thermistor, and PID control to supply power to the TEC chiller to cool the loop, i.e. can I set targets below the current temperature and have power applied when cooling is required and not heating? Will it cause issues with the thermal protection measures in the firmware?

Also can I read a dht11/22 sensor with a duet2 board to calculate the dew point so that I never chill the loop below that? Edit: Have found this in the documentation, I assume I can access the humidity data from the object model?

Any constructive thoughts would be much appreciated.

All the best
Barry M

[o_lampe]

@CNCModeller IIRC there is a reversed thermal fan control option in RRF. You could define the Peltier-output as fan I guess?

[CNCModeller]

@o_lampe said in Thermoelectric Cooler Peltier & Bed output:

@CNCModeller IIRC there is a reversed thermal fan control option in RRF. You could define the Peltier-output as fan I guess?

Thanks I'll give it a go

[o_lampe]

@CNCModeller I was curious myself and checked the Wiki for reverse thermostatic fan.
The only clue I found was the fan proportional mode:

M106 P1 T40:50 H1:2 ; Wiki example

my take:
M106 P1 T25:4 H1   ; temperature range reversed => Cooler switches on above 25° and off at 4°C

It's untested...

[CNCModeller]

@o_lampe thanks for the insight, I've also been reading up on heater definitions and an wondering if I can define negative characteristics for the heater, e.g. a heating rate of -1 deg/sec etc.

Plenty of experiments to go once I get home after Easter.

[o_lampe]

@CNCModeller I'm already watching the thread
BTW: Why not use a commercial chiller? Vevor CW5000 or 5200 can actually chill below ambient.
I prefer ice packs submersed in my coolant reservoir, because I don't use the laser 24/7

[CNCModeller]

It's just because I don't have a lot of space in my workshop and my cooler is quite large. I've been trying to optimise the kit in there (eBay has been my friend) so integrating a chiller into the K40 chassis would make a noticeable difference.