VFD stands for variable frequency drive. It can be used on our pumps inside of our glycol units as well as the condensers to control fan speed. It modulates the speed of a motor based off the load that is against it. In a glycol application, the load that is outside, this will monitor that pressure either speeds up or slows down the pump motor accordingly. It saves your power and gives you consistent pressure across the board. When put into a condenser, it increases the efficiency on a glycol chiller by modulating fan speed and making sure that pressure stays consistent all the time in the machine.