13. How big can you make a thermoelectric cooler in length and width? What limits the size?
About 50 mm in length by 50 mm in width is the typical upper size limit for TECs.
One side of the TEC contracts as it cools and the other side expands as it heats. This stresses the elements and solder joints. Since thermal expansion occurs on an inch per inch basis, the larger the cooler gets, the greater the stress becomes on the elements around the perimeter of the cooler.
In cases where the required heat pumping capacity exceeds that which could be provided by one TEC, additional TECs can be used side-by-side. In special cases, II-VI Marlow Industries will manufacture TECs up to 60mm x 60mm.