How many bottles of medium will I need to grow 1 vial of HUVEC out to 15 population doublings?

The amount of media needed per vial depends on the growth characteristics of the cells the size of the TC vessels and the split ratios used the frequency of media changes the type of experiments you perform etc. It is therefore difficult to give definite quantities. As a rough guideline 1-2 bottles (500 ml each) are needed for 1 vial of HUVEC.