NC dampers are opened when energized so I'm guessing the damper you're describing is actually a NO damper which is closed when energized. The spring at the NO damper will return the damper back to it's original position when de-energized, hence open. I recommend checking the fire code of the...
Here's how you calculate:
q: heat transfer rate, Btu/h
Trt: Room temperature, F
Tst: Supply Air temperature, F
V: Air flow rate, ft3/m
q= 1.085 x V x (Trt - Tst)
Metric form:
q: Watts
V: L/s
Trt, Tst: C
q = 1.2 x V x (Trt - Tst)
Note this calculation is based on sensible heat and it is used...
Thermal Gravity Effect calculation is usually taken into consideration when the temperature difference and the height of the vertical duct are significantly high. In most cased it is usually negligible.
Here is an example:
THERMAL GRAVITY EFFECT CALCULATION
D Pse : Thermal...
I agree with Drazen. I think that the upper HX was installed in the first place only to separate two circuits hydraulically. I also agree with ChasBean1 that a variable flow system will be quite feasible. I'd be surprised if the lower HX didn't have the capacity for the whole building.
