The baseline building fan system is summarized in this section. See Table 3.1-1 for the HVAC baseline building system mapping.
Total baseline building fan system power for the baseline building fan systems is given in Table 3.7.3-1. In this table, "cfms" is the supply fan air flow at peak design conditions. This is calculated for the baseline building with the sizing procedure described in Figure 2.4-1. This brake horsepower includes the supply fan, the return fan, and exhaust fans. Exhaust fans include kitchen hoods, toilets, fume hoods, and other miscellaneous fans that operate at design conditions.
Table 3.7.3-1: Building Descriptor Applicability for Fan Systems
|
Inputs |
Supply Fan |
Return/Relief Fan |
Exhaust Fans (Hoods) |
|
Modeling Method |
Yes |
Same as supply |
Yes |
|
Air Rated Capacity |
Yes |
Yes |
Yes |
|
Plenum Zone |
Not applicable |
Yes |
Not applicable |
|
Return Air Path |
Not applicable |
Yes |
Yes |
|
Fan Control Method |
Yes |
Same as supply |
Yes |
|
Brake Horsepower (bhp) |
Yes |
Yes |
Yes |
|
Static Pressure |
Yes |
Yes |
Yes |
|
Fan Efficiency |
Yes |
Yes |
Yes |
|
Fan Motor Efficiency (hm) |
Yes |
Yes |
Yes |
|
Fan Position |
Yes |
Not applicable |
Not applicable |
|
Motor Position |
Yes |
Yes |
Not applicable |
|
Part-LoadFan Power Curve(W) |
Yes |
Yes |
Yes |
|
Fan KW |
Yes |
Yes |
Yes |
Table 3.7.3-2: Baseline Building Fan System Details
|
Baseline System Type |
Baseline Break Horsepower |
Baseline System Fan Power |
Baseline Motor Efficiency |
|
1 PTAC |
n. a. |
P = 0.3 x CFMs |
n. a. |
|
2 PTHP |
|||
|
3 PSZ-AC |
bhp = CFMs Í 0.00094 + A |
P = (bhp x 746) / hm |
See Table 3.7.3-4 |
|
4 PSZ-HP |
|||
|
5 PVAV |
bhp = CFMs Í 0.0013 + A |
||
|
6 PVAV / PFP |
|||
|
7 VAV |
|||
|
8 VAV / PFP |
|||
|
9 HV Furnace |
n. a. |
P = 0.3 x CFMs OR |
n. a. |
|
10 HV Electric |
|||
|
11 SZ-VAV |
bhp = CFMs Í 0.00062 + A |
P = (bhp x 746) / hm |
See Table 3.7.3-4 |
|
12 SZ-CV-HW |
bhp = CFMs Í 0.00094 + A |
||
|
13 SZ-CV-ER |
|||
|
P Total baseline fan power to be distributed among the supply, relief, and exhaust fans in the same proportion as the proposed design. bhp The baseline building break horsepower (applicable to systems 3-8 and 11-13). A A break horsepower adder due to special conditions. See Table 3.7.3-3. CFMs The air volume in cubic feet per minute delivered by the supply fan. CFMnmc The air volume in cubic feet per minute delivered by the supply fan for non-mechanical cooling systems (applicable to systems 9 and 10). hm The baseline system fan motor efficiency taken from Table 3.7.3-4. |
|||
Table 3.7.3-3: Baseline Building: Fan Power Limitation Static Pressure Adjustment
Source: Table 6.5.3.1-2 of Standard 90.1-2016
|
|
Device |
Adjustment (A) |
|
Credits |
Fully ducted return and/or exhaust air systems |
0.5 in. w.c. (2.15 in. w.c. for laboratory and vivarium systems) |
|
Return and/or exhaust airflow control devices |
0.5 in. w.c. |
|
|
Exhaust filters, scrubbers, or other exhaust treatment |
The pressure drop of device calculated at fan system design condition |
|
|
Particulate Filtration Credit: MERV 9 through 12 |
0.5 in. w.c. |
|
|
Particulate Filtration Credit: MERV 13 through 15 |
0.9 in. w.c. |
|
|
Particulate Filtration Credit: MERV 16 and greater and electronically enhanced filters |
Pressure drop calculated at 2× clean filter pressure drop at fan system design condition |
|
|
Carbon and other gas-phase air cleaners |
Clean filter pressure drop at fan system design condition |
|
|
Biosafety Cabinet |
Pressure drop of device at fan system design condition |
|
|
Energy Recovery Device and other Coil Runaround Loop |
(2.2 × Energy Recovery Effectiveness) - 0.5 in w.c. for each airstream |
|
|
Coil Runaround Loop |
0.6 in. w.c. for each airstream |
|
|
Evaporative humidifier/cooler in series with another cooling coil |
Pressure drop of device at fan system design condition |
|
|
Sound Attenuation Section |
0.15 in. w.c. |
|
|
Exhaust Systems serving fume hoods |
0.35 in. w.c. |
|
|
Laboratory and Vivarium exhaust systems in high-rise buildings |
0.25 in. wc./100 ft. of vertical duct exceeding 75 ft. |
|
|
Deductions |
Systems without central cooling device |
-0.6 in. w.c. |
|
Systems without central heating device |
-0.3 in. w.c. |
|
|
Systems without central electric resistance heat |
-0.2 in. w.c. |