TEMs need to specific to the application you have in mind. Ideally, this would be done by modeling the system using something like computational fluid dynamic (CFD) software.
TE Technologies has an on-line calculator that gives you some idea of what is involved in this: https://tetech.com/peltier-thermoelectric-cooler-module-calculator/ A more sophisticated modeling tool is Laird Technolgies’ AZTECH software for Windows: https://www.lairdtech.com/support/learning-center/product-selection-tools/aztec-software-download
The modeling and solution design will probably need to be iterative so you can see the effects of various configurations of heat ejection solutions like heat sinks and fans.
Read Part 7 of this Tutorial - Buying Modules: https://www.collaborizm.com/thread/HkNShaadb
To see a Collaborizm project using thermoelectric modules, check out Cool India: https://www.collaborizm.com/project/SJVLyK2uZ