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Purpose of Program

Producers investigating anaerobic digestion on their farm need to know how much biogas is produced, how muc

An interactive web-based model is under development by researchers at Cornell University that will allow a us

Project Participants

Kifle Gebremedhin, Curt Gooch, Peter Wright, and Binxin Wu.

Project Categories

Environmental Conditions `

Digester Type and Geometry

Installation of DigesterBuilding Materials

Soil Conditions

Manure Information

Computer Tips

The program will guide you from one page to the next. We suggest you follow through to the "Summary" page.

NOTE: It may be easier to first print the 6 category pages. Then, once you've been able to look up the d

INTRODUCTION

If you need to change a value on a previous page, use your browser's "back" button or the "previous" button at

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is needed to heat the digester, and how much is left over for other uses. The value for each is largely based on

r to determine the biogas generation and resulting energy partitioning for various digester conditions specified by

ata, you can come back to the site and enter all of the information at one time.

the bottom of the page. Once you make the change, be sure to hit "update" at the bottom of the page. Othe

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he design of the system and the availability of biologically degradable energy in the influent. Only after accurate

the user. Items in the program that the user can select include digester size, type, and construction materials, hy

rwise, the program will not use the updated value in its calculations.

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alues are predicted can a producer make an informed business decision relative to anaerobic digestion on their f

draulic retention time, operating temperature, influent value, geographic location, and others. The model will be s

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arm and the design that works best for their conditions.

et up so a user can manipulate values for many of the input variables to do "what ifs". Reports can be generated t

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hat will document each variable value for each iteration. A future component of the model will be a module that w

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ill perform a complete economic analysis based on the design chos

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Values

1A. Enter latitude (degrees)

1B. (ft)

1C. Maximum Minimum

Month Temp. Temp.

January

February

March

April

May

June

July

August

October

November

December

Calm Very clear 0.9

Clear 0.85

High wind 11-20 mph 0.8

Other 0.6

0

ENVIRONMENTAL CONDITIONS

Item

Enter elevation abovesea level

Enter maximum andminimum monthlytemperatures in

degrees F for the

desired month (s)

WindSpeed(selectnumberfromTable 1)

SkyConditions (selectnumberfromTable 2)

September

Table 1. WindSpeed Averages

Table 2. Coefficient for Sky Condition

20mph

Mostly

cloudy 0.7

Hazy orsmoggy

Cloudsobscurethe sun

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Item Values

2A. Plug flow

2B.

Mesophillic (101 F)

Other

2C. days

2D.

Length (L) (ft)

Width (W) (ft)

Depth (D) (ft)

Length (L) (ft)

Width (W) (ft)

Depth (D) (ft)

Radius (R) (ft)

DIGESTER TYPE AND GEOMETRY

Digestertype

(selectone)

Mixed (availablesoon)

Operatingtemperature (selectone)

Thermophillic (135F)

F

Enterhydraulicretentiontime

Digesterconfiguration (selectone)

Rectangular with flattop

Rectangular witharch top

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Radius (R) (ft)

Depth (D) (ft)

Depth (D1) (ft)

Depth (D2) (ft)

Radius (R) (ft)

2E. Top cover (in)

Wall (in)

Floor (in)

Wall insulation (in)

Floor insulation (in)

Upright cylindricalwith flat bottom

Cylindrical withconical bottom

Enterthickness

Top cover insulation

(in)

Sidewall insulation(in)

Endwall insulation

(in)

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Values

6A. Option 1.

(lb/day)

6B. Option 2.

Milk Fat

Milk Fat

MANURE INFORMATION

Two options are available for inputting manureinformation. Be sure to include only the manure that isprocessed by the digester.

Item

(ft3/day)

Enter daily volume ofmanure entering thedigester

Enter daily volatilesolids

Manure entering thedigester is calculatedfrom the followinginformation using

standard equations

Lactating Cows -Group 1

Number ofCows

MilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

Lactating Cows -Group 2

Number ofCows

MilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

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Milk Fat

Milk Fat

Milk Fat

Lactating Cows -Group 3

Number ofCows

MilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

Lactating Cows -Group 4

Number of

CowsMilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

Lactating Cows -Group 5

Number ofCows

MilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

Lactating Cows -Group 6

Number ofCows

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Milk Fat

Dry Cows

Number of Dry Cows

(lbs)

Replacements

Organic Bedding for

(lbs/day)

Dry Cows (lbs/day)

Heifers (lbs/day)

Wastewater

Other Wastewater

MilkProduction

(lbs/cow/day)

Dry MatterIntake

(lbs/cow/day)

(g/gmilk/day)

Milk TrueProtein

(g/gmilk/day)

Average Body Weightof Dry Cows

Number of 1,000 to

1,250 lb heifersNumber of 800 to1,000 lb heifers

Number of 600 to 800lb heifers

Number of 400 to 600lb heifers

BeddingRequirements

Lactating

Cows

Milking CenterWastewater

(gallons/day)

(gallons/day)

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Values

4A.

Cover and Insulation

BUILDING MATERIALS

Item

Enter heat conductivity of building andinsulation materials from Table 3

Sidewall (BTU-in./hr-ft2-F)

Endwall (BTU-in./hr-ft2-F)

Floor (BTU-in./hr-ft2-F)

Cover (BTU-in./hr-ft2-F)

Sidewall insulation (BTU-in./hr-ft2-F)

Endwall insulation (BTU-in./hr-ft2-F)

Floor insulation (BTU-in./hr-ft2-F)

Top cover insulation (BTU-in./hr-ft2-F)

Table 3. Heat Conductivities of Building and Insulation Materials

Wall andFloor

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Material

13.87 1.03 1.65 0.95 0.73

Enter transmissivity of top cover material

GravelConcrete

Polystyrene BeadBoard

Polystyrene

CompositeBoard

Polystyrene -Expanded

(EPS)Polystyrene - Extruded

(XEPS)

Heatconductivit

y

(BTU-in./hr-ft2-

F)

4B. (Opaque = 0, Clear Glass or Plastic =1.0, White Plastic = 0.01-0.05)

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Values

5A.

Density

165.63 0.21 17.34

Granite 165 0.2 20.8

Quartz 166.25 0.19 61.03

Glass 169.38 0.2 5.55Clay 8.88

Gravel 14.33

Sand 16.45

21.78

14.7

6.24

Silt 8.62

Silt, stony 15.33

SOIL CONDITIONS

Item

Enter soil properties from Table4

Density (lb/ft3)

Specific heat(BTU/lb - F)

Heatconductivity(BTU-in./hr-ft2 -F)

Table 4. Thermal Properties of Soil Materials

Material SpecificHeat

HeatConductivity

(lb/ft3) (BTU/lb -F)

(BTU-in./hr-ft2 -F)

Soilminerals

Sand,saturated

Sand andgravel

Sand andclay

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Values3A.

INSTALLATION OFDIGESTER

ItemInstallationof digesterwithrespect tothesurface oftheground(selectone)

Underground(top wall isflush withtheground)

Partiallyunderground(Enterdepthbelow)

Aboveground(floor isflush withtheground)

Partialdepthunderground (ft

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Values

Environmental Conditions

Latitude (degrees) 43

Elevation (ft) 450

January 30 14 13 0.8

February 32 15 13 0.8

March 42 25 13 0.8

April 55 35 13 0.8

May 68 45 13 0.8

June 76 53 13 0.8

July 81 59 13 0.8

August 78 57 13 0.8

September 71 51 13 0.8

October 60 41 13 0.8

November 47 32 13 0.8

December 35 21 13 0.8

Digester Type and Geometry

Digester Type Plug flow

101

Hydraulic Retention Time (days) 22

Digester Configuration

Digester Dimensions

Length (ft) 104

Width (ft) 29

Depth (D1) (ft) 18

Depth (D2) (ft)

Radius (ft)

Thickness

Top Cover (in) 0.12

Wall (in) 11

Floor (in) 11

Top Cover Insulation (in) 0

Wall Insulation (in) 1.96

Floor Insulation (in) 1.96

Sidewall Insulation (in) 1.96

Endwall Insulation (in) 1.96

Installation of Digester

SUMMARY

Item

Max.

Temp. (F)

Min.Temp.

(F)

WindSpeed(mph)

SkyConditions

Operating Temperature (F)

Rectangular with flat

top

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Building Materials

Heat Conductivity of Building and Insulation Materials

10.4

10.4

10.4

2.29

1.04

1.04

1.04

0Transmissivity of Cover 0.01

Soil Conditions

Soil Properties

Specific Heat (BTU/lb - F)

Heat Conductivity (BTU/min-m - F)

Manure Information

2118

Daily volatile solids (lb/day) 0

Installation of Digester with Respect to the Surface ofthe Ground

Underground(top wall isflush withtheground)

Sidewall (BTU-in./hr-ft2-F)

Endwall (BTU-in./hr-ft2-F)

Floor (BTU-in./hr-ft2-F)

Cover (BTU-in./hr-ft2-F)

Sidewall Insulation (BTU-in./hr-ft2-F)

Endwall Insulation (BTU-in./hr-ft2-F)

Floor Insulation (BTU-in./hr-ft2-F)

Top Cover Insulation (BTU-in./hr-ft2

-F)

Density (lb/ft3) 90.52

0.19

6.93

Daily Volume of Manure Entering the Digester (ft3/day)

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Jan Feb Mar Apr May June July Aug Sep

OUTPUT

1. Heat Balance

Heat Gain(or Loss)(Btu)

Solar HeatGain 774808 1036486 1717663 2263017 2807262 2917542 2920118 2533927 1887244

HeatNeeded toHeatInfluent

19967424

318035092

919967424

319818783

416273816

512917599

911336816

012251075

314156273

9

Heat LossThroughTop cover 591955 524519 505794 406094 333463 264695 232305 251038 290075

Heat LossThroughWalls

83400860

75329809

83400860 64042035 59226698 52637289 51067918 52578803 54684295

Heat LossThroughFloor

52534878

47450857 52534878 39419578 40733564 39419578 40733564 40733564

39419578

Energy inEffluent(Manure +Gas)

24574790

122196584

624574790

123782054

924574790

123782054

924574790

124574790

123782054

9

HeatRequiredto OperatetheDigester

33542712

930261962

933439811

3

29979252

626022462

821858002

020248183

021354023

323406944

3

SupplementalEnergy

RequiredforDigesterHeating 0 0 0 0 0 0 0 0 0

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Jan Feb Mar Apr May June July Aug Sep

2. Gas Production

Biogas(ft3)

GrossBiogasProduction 2346217 2119163 2346217 2270532 2346217 2270532 2346217 2346217 2270532

BiogasNeeded toMaintainOperatingTemperature of theDigester 623470 562490 621557 557235 483688 406282 376360 396914 435073

NetBiogasAvailablefor OtherUse 1722746 1556673 1724659 1713297 1862528 1864250 1969856 1949302 1835459

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Oct Nov Dec Total

1328594 834686 668960 21690313

184680390

217652711

199674243

2049250415

378420 445974 547002 4771339

62852822 67258758

8340086078988101

2

40733564 39419578 5253487852566806

6

245747901

237820549

245747901

2893483355

287316603

323942336

335488025

3347880521

0 0 0 0

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Oct Nov Dec Total

2346217 2270532 2346217 27624813

534045 602123 623583 6222826

1812171 1668409 1722633 21401987