pump sizing

Job ID: 37221526

Budget: $30 – $250 USD

We have been tasked with draining and refilling antifreeze from diesel engines and rooftop mounted heat exchangers. We will be using a portable electric pump and 55 gallon drums. I need help determining the correct type of pump (centrifugal, gear, vane, etc) and required horsepower for the electric motor. The fluid loop that we need to pump into is as follows:
6” piping
Heat exchangers are located on the roof approximately 60’ in the air
Piping makes multiple 90 degree bends throughout the cooling loop
There are ten engines and heat exchangers. The number of 90 degree bends on each piping loop varies, but can be assumed safely at 8
In order to not bind the system with air, we need to pump at approximately 15 gallons per minute, this can be anywhere from 10-20 gallons per minute if needed

I need to find a pump and motor from a commercial seller like Grainger, but I do not know how to calculate pump head pressures, flow rates, etc. I also do not know what type of pump I need, like centrifugal pump, gear pump, vane pump, etc. Can you help?
Related categories: Mechanical Engineering Piping