A few more tests were conducted to get the performance.

Objective:

1. To measure the max. temperature difference.
2. To get the time for the steady stage

Experiment setup:

Data of the cooling:

Data of the water tank: 

Results:

1. The max. temperature difference of the insole was 4.9 deg
2. It took around 25 mins to get the steady stage
3. The max. temperature difference of the water tank was 5.5 deg

Conclusion:

Although the temp. different was 4.9 deg, the water droplets were condensed on the insole and cooling pipe already. After the testing, I put my feet on the cooled insole and the cool feeling ran through my feet.