Grain Systems PNEG-501 - Manual (Page 9)

9
Fan/Heater Application
AERATION SYSTEM REQUIREMENTS
Full perforated floors are recom-
mended in most DRYING situations. Floor
gauges and support spacing are dependent on
the grain load for a particular bin size. Please
inquire as to exact specifications. Flush floor
(formed in concrete) systems are recom-
mended when aeration only is desired. The
two most important aspects of aeration design
are the total perforated floor area and the
entrance duct cross-sectional area. Floors
should be sized for a maximum intended
airflow rate. To add larger fans or bin rings at
a later date may result in less than satisfactory
aeration performance.
These steps are intended as a mini-
mum requirement check for potential designs.
GSI floor designs will meet these require-
ments and be optimised for the best results.
STEP 8. Determine MINIMUM re
quired perforated floor area
using TOTAL AIRFLOW
from step 5.
PERFORATED AREA (sq ft) = TOTAL
AIRFLOW ÷ 30cfm/sq ft.
STEP 9. Determine MINIMUM cross-
sectional area of air supply duct.
SUPPLY DUCT AREA (sq ft) = TOTAL
AIRFLOW ÷ 2000 cfm/sq ft
IMPORTANT!
If more than one fan is used divide the
area by the number of fans. This is now the
area of each entrance tunnel.
To determine the inside width of the
supply ducts use the following formula. For
convenience it may be necessary to increase
this value to meet transition widths or "whole"
dimensions.
INSIDE DIMENSION OF SUPPLY DUCT
(ft) = SUPPLY DUCT AREA (sq ft) ÷
DESIRED TUNNEL DEPTH (ft)
STEP 10. MAXIMUM distance be-
tween bin wall and nearest duct = AVE
GRAIN DEPTH ÷ 4*
STEP 11. MAXIMUM distance be-
tween ducts = AVE GRAIN DEPTH ÷ 2*
* These are starting values ONLY. Adequate
distribution of ducts may require smaller
distances.