Whats the best way to invest my line of credit?

[Grayson Graham]

I work at a company that does construction financing and as a sort of bonus to the staff we get to fund one "office project" each year where we split the risk and profit amongst ourselves. This is my first year participating in the office project so recently i went to the bank and got a line of credit for $190,000 at 4.5%. Most of this money will be invested in the office project 6 to 9 months of each year. Which leads me to my question:

Whats the best use of $190k credit line for only 3 to 6 months of each year?

After the 2018 project is finished should i just pay off the line and wait to use it again for the 2019 project? That seems boring...

Thank you for taking the time to help me come up with some ideas!