I want to drive a couple of 12 Volt peltier devices. Maybe 30 or 60 watts and I want to ramp down the DC power to the peltiers on shutdown over a period of around 5 minutes or so to zero volts / amps. The ramping time period is not terribly important. I just want the cooling fan on the peltier to be able to draw the residual heat off so it doesn’t slam back into the thing I just cooled. So I’m guessing 5 minutes ought to be OK. Maybe 10? I have not purchased the peltiers yet so I have no empirical data.
I have learned that I can use a switching PS like an ATX unit to drive the peltiers so long as there are no other loads matching one PS to one Peltier.
I also don’t know whether it’d be more straight forward to build a ramping device for each peltier or for a group of them. Prolly one each would be smartest, I’m thinking.
Any help? Know of any circuit designs that will do what I am looking to accomplish?
The simpler the circuit the easier for me to breadboard it together.
Elegance is not my goal.
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Some background info you may or not care to know:
I've looked at two ways of doing this:
1.) Mineral oil pumped up from a reservoir in another room (cellar) where I can heat or chill it using a water heater element or an old converted Dehumidifier respectively then into a heat exchanger coil of SST tubing inside the Fermentor.
2.) peltier units mounted to an aluminum platen that has one side machined to conform to the radius of my Fermentor and mounted to it.
What's my app?
Beer. 12 gallons of beer.
I have a Fermentor for which I want to regulate the temperature.
I figure I have 40 watts of passive load if I don't insulate the Fermentor and 20 if I do. That's something that 2 or 3 peltiers in the 30 - 60 watt range can handle easily
The thermal range I want to bring my beer to lies between 64 degrees and 78 degrees F, specific temp' of course depending on the brew the yeasts and the result I want.
The up side to peltiers is that I don't pierce the Fermentor with anything that might harbor bacteria. They are reversible so they can heat as well as chill. Controlling them would be VIA a SSR which would be switched by a computer based unit called the BCS 460 or simple PID units and thermocouples. Reversing polarity for warming the brew is a thing I can do manually because I either want the brew above ambient or below. But, I won't need to be driving temperature up and then down in the same brew cycle.
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But I suck at electricity. I mean, I can wire a dual pole set of light dimming switches, but household electrical work is about the apex of my accomplishments.
I have learned that I can use a switching PS like an ATX unit to drive the peltiers so long as there are no other loads matching one PS to one Peltier.
I also don’t know whether it’d be more straight forward to build a ramping device for each peltier or for a group of them. Prolly one each would be smartest, I’m thinking.
Any help? Know of any circuit designs that will do what I am looking to accomplish?
The simpler the circuit the easier for me to breadboard it together.
Elegance is not my goal.
****************************
Some background info you may or not care to know:
I've looked at two ways of doing this:
1.) Mineral oil pumped up from a reservoir in another room (cellar) where I can heat or chill it using a water heater element or an old converted Dehumidifier respectively then into a heat exchanger coil of SST tubing inside the Fermentor.
2.) peltier units mounted to an aluminum platen that has one side machined to conform to the radius of my Fermentor and mounted to it.
What's my app?
Beer. 12 gallons of beer.
I have a Fermentor for which I want to regulate the temperature.
I figure I have 40 watts of passive load if I don't insulate the Fermentor and 20 if I do. That's something that 2 or 3 peltiers in the 30 - 60 watt range can handle easily
The thermal range I want to bring my beer to lies between 64 degrees and 78 degrees F, specific temp' of course depending on the brew the yeasts and the result I want.
The up side to peltiers is that I don't pierce the Fermentor with anything that might harbor bacteria. They are reversible so they can heat as well as chill. Controlling them would be VIA a SSR which would be switched by a computer based unit called the BCS 460 or simple PID units and thermocouples. Reversing polarity for warming the brew is a thing I can do manually because I either want the brew above ambient or below. But, I won't need to be driving temperature up and then down in the same brew cycle.
***************************************************
But I suck at electricity. I mean, I can wire a dual pole set of light dimming switches, but household electrical work is about the apex of my accomplishments.
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