“we bring engineering to life” 2015 agent training grant ellington nov. 18, 2015
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“We Bring Engineering
to Life”
Biological and Agricultural Engineering
2015 Agent TrainingGrant EllingtonNov. 18, 2015
Topics• Energy cost update• Automatic ventilation controls• Heat recovery system evaluation• Modular tray steaming system• Farm Safety information
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 20200
5
10
15
20
25Propane Natural Gas
2011
Dol
lars
per
Mill
ion
BT
U
Source: U.S. Energy Information Administration (LP Gas – Wholesale/Resale; N.G. – Commercial)
LP Gas and Natural Gas Price Outlook
$18 / MMBTU @ $1.30/gal
$9.40 / MMBTU @ $0.75/therm
$11 / MMBTU @ $0.80/gal
$8.10 / MMBTU @ $0.65/therm
Natural Gas ($/therm)
LP Gas ($/gal)
No. 2 Fuel Oil ($/gal)
Wood Chips ($/ton)
0.20 0.18 0.28 280.30 0.27 0.42 420.40 0.37 0.56 560.50 0.46 0.70 700.60 0.55 0.83 840.70 0.64 0.97 980.80 0.73 1.11 1120.90 0.82 1.25 1261.00 0.92 1.39 1401.10 1.01 1.53 1541.20 1.10 1.67 1681.30 1.19 1.81 1821.40 1.28 1.95 1961.50 1.37 2.09 2101.60 1.46 2.22 2241.70 1.56 2.36 2381.80 1.65 2.50 2521.90 1.74 2.64 2662.00 1.83 2.78 2802.10 1.92 2.92 2942.20 2.01 3.06 308
Fuel Cost Comparison
* Heating System Efficiencies are assumed equal
2014
Automatic Ventilation Control – Improving Curing Management and Energy Efficiency
Most automatic systems measure relative humidity directly, but display dry-bulb and wet-bulb temperature.
2014 County Agent Survey Data(85,000 acres reported)
0
10
20
30
40
50
60
70
80
90
100
55
45
Wet-bulb Automatic Ventilation
% A
cres
Real-time Continuous Monitoring of the Curing Environment
• Significant time management tool for growers• Web-based access to monitoring system• Audible alarm conditions to help minimize leaf damage during
equipment failures or power loss• Data logging capabilities• Suretrol or Cureco, Marco Mfg., Enercorp (Flue-Cured Tobacco
Services, LLC.), Rotem Control & Management Systems (Britt Technical Service)
Curing Issues?• Regardless if manual control or automation is utilized for curing,
system inputs are still determined by grower• Yellowing stage duration and at what temperature, what humidity,
when to begin advancing, etc., are mainly inputs based on growers experience curing
• However, there can be a combination of weather and agronomic factors that results in extreme difficulty producing the desired cured leaf quality
• Ideal curing schedules (dry-bulb and wet-bulb temperature profiles) are going to vary each season and within a given season
• Curing guidelines posted on the Growers Portal
Exhaust Air Heat Recovery System Evaluation
FAN
Heat Exchanger
Tobacco Curing BoxesTobacco
Heated Air
IntakeAir
Exhaust Air
Heat Exchanger (recovery coil)
Heat Recovery System Schematic Heat Exchanger (preheat coil)
Exhaust Vent Heat Exchanger(recovery coil)
Intake Vent Heat Exchanger
(preheat coil)
Single Cure Evaluated Diff. = 63 gals (17%)
0 24 48 72 96 120 144 168 192 2160
10
20
30
40
50
60
70
80Barn 51 (Heat Recovery System) Barn 52
Time (hrs)
Dai
ly F
uel U
sage
(gal
s)
Cure 7 Daily Fuel Usage Comparison (60 gallons difference)
0 24 48 72 96 120 144 1680
10
20
30
40
50
60
70
80
90Barn 51 (Heat Recovery System) Barn 52
Time (hrs)
Dai
ly F
uel U
sage
(gal
s)Cure 9 Daily Fuel Usage Comparison
(55 gallons difference)
DeCloet DeCloet w/HRS *Long *Long w/HRS0
50
100
150
200
250
300
350
400
278
226
366
303
LPG
(gal
)
Exhaust Air Heat Recovery System Average Fuel Savings – 2014(DeCloet Barns – 10 Cures; Long Barns – 1 Cure)
* Last Cure Only
52 gals (20%) 63 gals (17%)
Long Long w/HRS DeCloet DeCloet w/HRS0
200
400
600
800
1000
1200
1400
1600
1800
1265
1109
1587
1321
Exhaust Air Heat Recovery System Results – 2015(Total Fuel Usage)
LPG
(gal
)
4 Cures 6 Cures
Long Long w/HRS DeCloet DeCloet w/HRS0
50
100
150
200
250
300
350
316
277265
220
LPG
(gal
)Exhaust Air Heat Recovery System Average Fuel Savings – 2015
(DeCloet Barns – 6 Cures; Long Barns – 4 Cures)
39 gals (12.3%) 45 gals (16.8%)
Exhaust Air Heat Recovery System Summary • Fuel savings averaged over the season for both barn makes was
approximately 15% per cure (ranged 30 to 58 gallons)• Curing time was not extended• Burner ON/OFF cycles reduced• Cured leaf was darker in the DeCloet barn with system• System cost is approximately $1800 installed• Simple payback at 15% savings is approximately 5 to 6 years (2015
prices, 8 cures per season)• Plan to continue in 2016
– add more barns with tube-axial fan configurations
Modular Tray Steaming System – 2014
System Specifications• Container dimensions: 6’ x 5’ x 10’ (300 ft3)• Approximately 450 trays• 176oF (80oC) for 30 min.• Steam generator with fuel oil burner
– 0.6 gpm @ 150 psi = 100,000 Btu/hr (420,000 Btu/hr max)– 8 to 9 gph water input – 210 to 215oF (saturated steam)
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25 3.5 3.75 4 4.25 4.5 4.75 5 5.25 5.5 5.75 660
70
80
90
100
110
120
130
140
150
160
170
180
190
200Front Door Floor Air Temp. 2nd Tray from bottom 2nd Tray from Top Series7
Time (hrs)
Tem
pera
ture
(oF)
10:00 am
Temperature Profiles vs. Time
176
176 oF (80 oC) for 30 min.
Steaming Trays 2016 & Beyond• Commercial units are probably going to be available in 2016• Growers can make their own system
– 176 oF (80 oC) for 30 minutes– Btu/hr requirement will scale with container volume (350 Btu/hr per
ft3 capacity)– Insulation not required– Only the largest operations will need 1000+ tray capacity– Must use steam not dry heat
Farm Safety Resources• Tobacco guide will include information on Ag machinery hazards• Information and links will be posted on Tobacco Growers Portal • Certified Safe Farm Program• http://www.nclabor.com/ash/ash.htm• National Ag Safety Database (NASD)• National Institute for Occupational Safety and Health (NIOSH)
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