Hello everyone, I am trying to simulate earth tubes for pre-cooling using the EnergyPlus software. Basically a fan will be used to circulate ambient air through an underground horizontal pipe. The software requires an input field of "Fan Pressure Rise" which Im guessing is the pressure that is created by the fan to force air through the pipe. My question is, how can I calculate the pressure that needs to be generated to make the air flow through the pipe? System specs are: pipe length = 50m diameter (internal) = 0.3m velocity = 2 m/s volume flow rate = 0.14m^3/s Thanks.