I have some self-imposed constraints for this project. 

1. Product to be modular and not physically attached to coffee cup.

   -this design is to slide up beside a coffee cup.

2. Coffee cup to be a regular size and made of ceramic.

   -heat transfer would be better with a metal cup, but since the average person likely only has ceramic cups, that will be what is used in testing.

3. Use of only one thermo-electric generator (soft constraint).

   -the heat sink style I've selected only works with one generator, it is also ideal to only have one due to cost. The trouble with this will be that these do not generate a lot of voltage, so it may be difficult to step the voltage up to something a motor can use. Multiple TEGs (thermo-electric generators) can be used in series to output a higher voltage. This may be necessary to get a useful voltage, but would require a redesign and would have it's own difficulties to implement.

4. Energy from heat differential must spin a fan, and have a noticeable on how much time it takes for a hot cup of liquid to cool down.

   -Spinning a motor from energy generated is the ultimate goal of the project. I'm expecting that any extra airflow will increase the cooling rate. I will need to do a control test however of what effect simply placing the project beside a cup will have. Having the project beside a cup may help insulate the drink, or even pull heat away from it on it's own.

It may be that a simple heat sink placed beside a coffee cup would be more effective that my intended design, but the point of the project is to explore harvesting energy and using it for electrical power in a "real world" application.