DIY Thermoelectric Peltier Refrigeration

[limpalot]

I was thinking of a caravan setup, cost little to run and cool air in the heat of the day. Hot water for a shower at night.

 

[ctxkid]

I was thinking of a caravan setup, cost little to run and cool air in the heat of the day. Hot water for a shower at night.

we run on the the same rail

 

[Occasional_panner]

Nightjar,
I cant tell from the eBay description, are you able to separately set the on & off temp?
For instance, turn on at 20 deg and off at 15deg.
I imagine control over the hysteresis would be important for longevity of fans etc as well as perhaps being a little more efficient with the power usage.

Bicter,
On the thermostat shown in above pic you can "set" activation temperature but not the cutout temperature.
The readout on the pic is the ambient temp (difficult to read) 23.8C. You probably notices the Engel ambient temp reads 25, I was fiddling remember so they don't match.
For the test I set the activation at 22C so the Peltier is running, when the ambient drops to 20C it will automatically cut out. The thermostat is designed this way (2C cut out lag) so what ever device you are controlling doesn't cut in & out if the ambient temperature hovers around your set point.
No doubt there are thermostats that you can set upper & lower temps. In this instance working with the ambient temperature suffices.

CTX, Totally agree, very addictive. Years ago knocked up a random number picker 1 - 45 using led's and electronics, it worked but never gave me the winning lotto numbers. :lol:

These are a nightmare to work out, someone on youtube posted a good vid on one
https://www.youtube.com/watch?v=yVD0zkZTe00

Skip to 4.20 it gives the options.

I used to use these on something else but went with a custom dual channel board in the end, but they were very reliable and value for money.

 

[Nightjar]

These are a nightmare to work out, someone on youtube posted a good vid on one
https://www.youtube.com/watch?v=yVD0zkZTe00

Skip to 4.20 it gives the options.

Instructions post #30 makes it easy.

Going to try one of these with the Peltier setup. If successful will be handy when picking up town supplies and keeping them cool until we get back to the caravan fridge/freezer.

https://www.ebay.com.au/i/153686136...biUIKq1K_5LH8ImnZMWyRIK_baViRil8aAkv3EALw_wcB

 

[Occasional_panner]

Adjusting P1 will give you hysteresis, so no it doesn't have to be within 2 deg.

 

[ctxkid]

Thanx TJ the thermo switch link works a treat, cheers for the heads up erfect:

latest pics, a coupla days ago

had some water in the can , worked ok :Y:

 

[Occasional_panner]

Ctx, have you tried it without a pump, just using the thermosyphon principle
Like here https://www.researchgate.net/figure...cuated-tube-solar-water-heater_fig3_256854680
It would give you one less thing to fail and doesn't draw power.

 

[ctxkid]

Ctx, have you tried it without a pump, just using the thermosyphon principle
Like here https://www.researchgate.net/figure...cuated-tube-solar-water-heater_fig3_256854680
It would give you one less thing to fail and doesn't draw power.

yes i tried it , but not as efficient (muuuuuuuuch slower) as pumping the water around, my latest pump is submersible and draws .4ah

 

[Nightjar]

Australia Post had these on display $60.00. Last week managed to get one for $40.00
Watch this space to see how it performs with a Peltier inserted through the wall.
When we travel 140+kms into town and back to top up supplies it maybe ideal to keep the perishables chilled until we get back to the caravan.