Examples – Grain Systems PNEG-501 User Manual
Page 10
10
Fan/Heater Application
EXAMPLES
SITUATION:
On farm aeration of dry soybeans. 42" diameter, 9 rings, NSL series farm bin
with 24" eave height. A flush floor aeration system with one fan will be used.
1.
AVE GRAIN DEPTH, peaked = 24' + (42' /12) = 27.5'
2.
Select 1/10 CFM/BU aeration rate for beans
3.
From the STATIC PRESSURE TABLE for BEANS at 28' (use the next
higher value or approximate) and 1/10 cfm/bu the static pressure is .91" of
water.
.91" water column
4.
Bin capacity, BUSHELS
27.5' x 0.6594 x 42' x 42' = 31988 BUSHELS
5.
Required TOTAL AIRFLOW, CFM
0.1 cfm/bu x 31988 bu = 3199 CFM
6.
From the FAN PERFORMANCE TABLE for vane axial fans, at 1" (0.91")
static pressure and 3500 cfm (closest to 3199 cfm), the appropriate fan would
be a 1.5hp-18"
7.
Number of ROOF VENTS
3500 CFM ÷ 1800 cfm/vent = 1.94, therefore 2 vents
8.
PERFORATED AREA of floor, sq ft
3199 cfm ÷ 30 cfm/sq ft = 106.6 sq ft, minimum
9.
SUPPLY DUCT AREA, sq ft
3199 cfm ÷ 2000 cfm/sq ft =1.60 sq ft, minimum
ID of supply duct for 12" deep tunnel = 1.6 sq ft ÷ 1.0 ft = 1.6 ft or 1.8"
10.
Maximum distance between ducts and binwall = 27.5' ч 4 = 6.9'