Recent content by ballsonwalls

It is actually Darcy-Weisbach. My mistake.

the pressure drop is proportional to the velocity squared

Pressure drop in a pipe is determined by the D'arcy Weisbach equation. This states that pressure drop is a function of the velocity of the fluid of the pipe (among other things). The required GPM for heat transfer is GPM = BTUH/(500 * delta T) where delta T is leaving water temperature minus...

I have a main 3,000 gallon fuel tank on grade. They are pumping to a day tank in a penthouse about 70 feet above grade which are supplying boilers. The boilers require about 40 CFH. Also, this tank is supplying the day tank of an emergency generator on grade, about 20 feet away. The generator...

Shut off valves, two way valves, balancing valves

I am using a plenum fan (greenheck QEP) for a somewhat atypical situation and the maintenance engineer doesn't want to have to "bend down" to change the belts (eye roll). Is there a way to raise the fan without having to build a concrete pad that is 4 feet high? The fan has been purchased but...

For a chilled or hot water system? Thanks

and all ductwork, exhaust, etc. this was my first project.

To design an HVAC system on the shell and core of a 90,000 S.F. office/lab building with a boiler/chiller plant in a mechanical penthouse, each with primary/secondary pumping, with 2 boilers, 2 chillers and 2 cooling towers. There are a total of 4 VFD air handling units. There is also a 4,000...

I have been working on a renovation project in which there is a 20,000 cfm VAV air handler with 19,000 cfm connected capacity. I sized my return fan at 17,000 cfm at 2.5". The total exhaust through toilet/laundry rooms is 1200 cfm, leaving 17,800 cfm to be returned. There are VAV two air...

I'm new to the industry and I'm a bit confused on sizing supply and return fans. It seems that supply fans are sized for the external static pressure losses at the outlet. However, a return fan is sized for the static pressure losses at the inlet. Why is this theoretically the case? How...

I took the FE exam yesterday and am very confident that I passed. I've been out of school and working for a year. Does the year that I've been working prior to taking the FE count towards my 4 years of experience required for the PE? I know I should probably check what my state says about...