I am looking for advice on choosing some thermo-electric coolers for a project.
I need to maintain an aluminum plate at -30°C, while keeping the hot side of the element at a temperature of 20-25°C with a water-cooling system. The system would be exposed to room tempearture, so I would need atound 10W to maintain the -30°C, when I have reached that temperature. Using multiple elements is imaginable to keep compenstae the 10W income. And multiple modules would help having an even spread of temperature along the aluminum plate.
Do you have any recommendations on which Peltier module might get the job done?
There are a number of posts here describing the selection and application process for these devices in some detail. Doing your homework ahead of time will go a long way toward helping you get a good result.
Much hinges on how accurate your 10W thermal load figure is; it’s a figure that needs to be understood well. You also need an accurate estimate of your hot side temperature; don’t figure any less than a 5°C difference between the hot side and the ambient environment into which that heat is ultimately being rejected.
Since you’re looking at a 60°C+ temperature difference overall, you’re not not going to get a lot of heat flow. If you buy lower-performance devices with a Tmax figure around 64°C, you’d need devices with a Qc(max) figure upwards of 160W to have a chance. Better-performing products like Laird’s HiTemp ETX series (if the specs are to be believed) may allow the job to be done with Qc(max) figures maybe around the 40W mark. Expect to supply 100W or more of input power to the system in order to move that 10W of thermal power.