“We Bring Engineering to Life” 2014 Agent Training Grant Ellington Nov. 19, 2014.

“We Bring Engineering

to Life”

Biological and Agricultural Engineering

2014 Agent TrainingGrant EllingtonNov. 19, 2014

Topics• Energy outlook• Biomass system update• Automatic ventilation controls• New curing barn energy assessment – part II• Heat recovery system evaluation• Modular tray steaming system

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

Hurst Boiler Biomass Fired Hot Water Heating System; 2012 - 2014

Woodchip Biomass System and Automated Controls,

3.4 MMBtu/hr

Water to Air Heat Exchanger installed

in Return Air Plenum

Greenhouse Heating Applications w/Biomass Unit

Curing Barns and Greenhouse Applications

Result in Extending System Operation from July - March

Harnett Co.

Max Ox Smaller Capacity Biomass Heating System – 11 Barns and 200’ Greenhouse Application

(900,000 Btu/hr)

Person Co.

Performance Information Summary  Hurst (2012) Max Ox (2013)

Boiler Capacity 3.4 million Btu/hr 1 million Btu/hr per unit

Number of Barns 17 11

Green Leaf Loading (lbs/barn) 18,000 13,000

Cured Leaf Weight per Cure (average, lbs/barn) 3,000 2,375

# of Cures 131 60

Total System Cost $300,000 -

Fuel Type Dry Wood Waste Green Chips

Season Total Fuel Usage (ton) 250 216

Fuel Cost ($/ton) $30 $25

Fuel Usage per Cure (ton) 1.9 3.6

Fuel Cost per Cure $66* $90

Fuel Cost per lb of Cured Leaf $0.02 $0.04

*Includes electricity cost for boiler.

Automated Biomass Fired System• Advantages

– Reduced fuel cost (70 to 90%)– Abundant renewable fuel– High combustion and thermal efficiency– Automated system (combustion controls, emissions, ash removal)– TSNA NOx mechanism eliminated

• Disadvantages– High initial investment– More equipment maintenance– Increased management – Limited or no local service technicians

Automatic Ventilation Control – Improving Curing Management and Energy Efficiency

Most automatic systems measure relative humidity directly, but display dry-bulb and wet-bulb temperature.

2013 County Agent Survey Data(86,000 acres reported)

0

10

20

30

40

50

60

70

80

90

100

48.1

40.8

Wet-bulb Automatic Ventilation

% Acres

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., and Enercorp (Flue-Cured Tobacco

Services, LLC.)

New Curing Barn Performance Evaluation

Background• Energy usage remains a significant input cost • Considerable price fluctuations of petroleum fuels in recent years and

continued uncertainty of future prices• More growers continue to make energy efficiency improvements to

existing infrastructure and replacing older barns • Approximately 15,000 to 18,000 operational barns in NC • 6 manufacturers made barns for the 2014 season• Energy efficiency and energy conservation is the best source of new

energy and is a cost-effective solution• Research continues to explore energy efficiency improvements and

renewable energy technologies that are economically feasible

Primary Objectives • New curing barn assessment to provide on-farm independent energy

and other performance related information to assist growers with curing infrastructure decisions– Total energy footprint (LP gas and kWh usage)– Green and cured leaf weights – Cure duration– Static pressure (airflow)– Cured leaf quality, barn curing management (user-friendly)

• Exhaust air heat recovery system evaluation

New Barn Specifications• Long (10-box)

– Long HEx @ 350,000 Btu/hr

• World Tobacco (15-box)– Evans HEx @ 500,000+ Btu/hr – 2” insulated panels

• Tytun (14-box, 32T)– Powermatic HEx @ 400,000 Btu/hr – 4” insulated panels

• Taylor (10-box)– Evans HEx @ 390,000 Btu/hr – 3” insulated panels

• All fan motors 1-phase, 10 Hp, except Tytun 18-box and Long Prototype (15 Hp) • All barn pads insulated • Suretrol controllers on all barns

• Long Prototype (10-box)– Long HEx @ 400,000 Btu/hr

• World Tobacco Basic (12-box)– Evans HEx @ 325,000 Btu/hr – 2” insulated panels

• Tytun (18-box, 32T)– Powermatic HEx @ 550,000 Btu/hr

Heat Exchanger and Burner Operating Efficiently– set the burner firing rate correctly (325,000 to 425,000 BTU/hr typical range)– burner and all controls properly adjusted

Box ComparisonLong, Taylor Tytun (32T) World Tobacco,

DeCloet

Tytun - 18 Tytun - 14 Long - Prototype

Taylor - 10 Long - 10 World - 15 Existing Long

Existing DeCloet

World - 120

50,000

100,000

150,000

200,000

250,000

300,000

350,000

Lbs G

reen

Lea

f

Total Green Weight – 10 Cures

Tytun - 18 Tytun - 14 Long - Prototype

Taylor - 10 Long - 10 World - 15 Existing Long

Existing DeCloet

World - 120

10,000

20,000

30,000

40,000

50,000

60,000

70,000

Lbs C

ured

Lea

f

Total Cured Weight – 10 Cures

Existi

ng Long

World

- 15

Long

- 10

Tytu

n - 18

Existi

ng DeCloet

Long -

Proto

type

Tytu

n - 14

Taylor -

10

World

- 12

0

1

2

3

4

5

6

7

8

9

10

Days

Season Average Cure Duration(10 Cures)

Long - Proto-type

Tytun - 18 Long - 10 Existing Long World - 15 Taylor - 10 Tytun - 14 Existing DeCloet

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

kWh

Season Average Electrical Energy Usage

15 Hp10 Hp

7.5 Hp

Taylor - 10 World - 12 Tytun - 18 Long - Prototype

Tytun - 14 Long - 10 Existing DeCloet

World - 15 Existing Long

0

2

4

6

8

10

12

14

16

18

20Mid and Upper-Stalk Cures Only All Cures

lbs

Cure

d Le

af /

gal

LPG

*

* No lower-stalk cures

2.3 ¢ / lb14.5

11.5

2014 Season Average Curing Efficiency Comparisons

 Fuel Efficiency(lbs/gal)

Fuel Cost ($/unit)

0.80 1.00 1.20 1.40 1.60 1.80 2.00

$ / lb Cured

7 0.114 0.143 0.171 0.200 0.229 0.257 0.286

8 0.100 0.125 0.150 0.175 0.200 0.225 0.250

9 0.089 0.111 0.133 0.156 0.178 0.200 0.222

10 0.080 0.100 0.120 0.140 0.160 0.180 0.200

11 0.073 0.091 0.109 0.127 0.145 0.164 0.182

12 0.067 0.083 0.100 0.117 0.133 0.150 0.167

13 0.062 0.077 0.092 0.108 0.123 0.138 0.154

15 0.053 0.067 0.080 0.093 0.107 0.120 0.133

17 0.047 0.059 0.071 0.082 0.094 0.106 0.118

Energy Efficiency and Estimated Cost per Pound Cured Leaf (fuel only)

Summary• Approximately 25% increase in fuel efficiency averaged over the season• 6 barn manufacturers made and sold barns in 2014• Energy performance alone is not the single justification for purchasing a

given barn make, but remains an important factor– New barn costs– Material handling capacity– Existing barn infrastructure– Existing material handling system– Serviceability and maintenance costs

• Independent performance information can help manufacturers with developing and implementing technologies to improve overall barn design

• Demand for used all metal barns ?? • Plan to continue work in 2015

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)

DeCloet DeCloet w/HRS *Long *Long w/HRS0

50

100

150

200

250

300

350

400

278

226

366

303

LPG

(gal

s)

Exhaust Air Heat Recovery System Average Fuel Savings – 2014

* Last Cure Only

Modular Tray Steaming System

System Specifications• Container dimensions; 6’ x 5’ x 10’• Approximately 450 trays• 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 – T = 210 to 215oF (steam)

60

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 Series9 Series11

Time

Tem

pera

ture

(oF)

Temperature Profiles vs. Time