# Austrian by keara

VIEWS: 46 PAGES: 8

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```									Simplified Kachelofen Calculator
Revised: Oct 17/09 Max Output Heating Cycle Lower Heating Value Efficiency Max Fuel Load Minimum Fuel Load Firebox surface area Firebox floor area Firebox width Firebox depth Fbox width/depth ratio Firebox height Minimum channel length Chosen channel length Gas slot area Optimum burn rate Averaged channel gas flow Averaged channel gas temp N. Senf Pn tn LHV ŋ mb mb_min Obr Abr Wbr Tbr Hbr Lz_min Lz Ags m_BUopt V_G/s t 6.0 12 4.16 0.76 22.8 11.4 20496 2505 50 50 1.00 103 6.20 5.00 23 17.8 0.062 282

Converter: Instructions: kW 19,456 BTU/hr Enter maximum output and heatin h Enter firebox width in the light gree kWh/kg The yellow boxes are calculated b The dark green boxes are constan kg 50.2 lb kg 25.1 lb sq cm sq cm cm 20 inches Minimum firebox width is 25 cm cm 20 inches width/depth ratio must be between 0.5 and 2.0 cm 41 inches m 244 inches m 197 inches sq cm kg/h cu m/sec deg C 539 deg F

Notes: * This is a first draft, for educational purposes. Use at your own risk. * * * * * * * * * * * *

Normally, a channel length larger than the minimum is chosen. A chimney calculation is then done Channel sizes and number of bends is chosen Then, a pressure calculation is done to see whether the channels are too long, or too tight It is an iterative process, repeated until the channel configuration satisfies the pressure calcul This will generate a new, higher efficiency number for channels that are longer than the minim The chimney and pressure calculations will be added to the spreadsheet at a later date

The calculations are based on burn rate, which assumes small, Austrian style wood, regardle Larger wood has a lower burn rate The stated validity for the calculations are for heaters up to 40 kg Max Fuel Load. The efficiency number is based on the Lower Heating Value (LHV) of wood (European definit To convert to a North American (Higher Heating Value, HHV) efficiency number, subtract app

The calculations are based on the formulas published in "Bemessung von Kacheloefen", Baumgartner, Hofbauer, et. al., Oesterreichischer Kachelofen Verband (Austrian Stovebuilders Guild), Vienna, 1996 First Draft, October 5/09

tructions:

er maximum output and heating cycle in the light green boxes er firebox width in the light green box yellow boxes are calculated by the spreadsheet dark green boxes are constants, that can be changed

mum firebox width is 25 cm

els are too long, or too tight n satisfies the pressure calculation s that are longer than the minimum, but that still draft. eadsheet at a later date Austrian style wood, regardless of heater size

kg Max Fuel Load. HV) of wood (European definition of efficiency) fficiency number, subtract approx. 10%

0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS

Conversions
sq in sq m 144 23.00 sq. m. 0.0864 Length and Area sq in sq. ft 35650 247.57 Efficiency Moisture% lbs Wood

l/sec cfm

15.00 20.00

cfm 31.8

Flow l/sec 9.434

pa pa psi in H2O in Hg 15.00 1.00 1.00 1.00 6944.00 250.00 3410.68

Pressure psi in H2O 0.00216 0.060 27.71 0.04 0.49 13.61

mm H2O 150

bar 1500000

atm 1519875

kW kcal MJ BTU kWh BTU\h kcal\h

9.50 37432.00 43.54178 156.7504 1.00 0.2778 140000.00 41.03064 1.00 1 3.60 8000.00 2.346041 1.00 0.001163

kW 9.5

Power and Work kWh MJ

BTU 3.97

kcal 37432 238.8 35264.484 860

kcal\h 8170

BTU\h 32427

8000 1

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0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS

Heat Output Calculation BTU kW x 12h Kw X 8h 1 20 1 6880 0.17 0.25

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Sizing Calculator for Custom Heaters
Project: Case: YMCA Earth Residences Height: 90" Perimeter: 32+80+38+60+79"

INPUT: CONSTRUCTION TYPE:(A,B,etc.) d A B C D

INPUT: SURFACE AREA

sq in + sq ft + sq m

0 290 0

Construction Type light medium medium-heavy heavy sq. m. sq. in 0 0 26.941 41760 0 0

w/sq m OutputHI 1280 1100 850 700 sq. ft 0 290 0

Construction Type: Total Area in sq m is Design Surf Temp is to Design Output is to

heavy 26.94 Deg C Deg C 13.5 18.9 kW kW = = kW 13.47 18.86 MJ/h 3.74 5.24 kcal\h 11585 16218

0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS printed on 5 Page 11/2/2009

rs

w/sq m OutputLO 1100 850 700 500

SurfTHI SurfTLO

Heat Output Calculation BTU kW x 12h Kw X 8h Efficiency 68.86 Moisture% 19 lbs Wood 67.1 31789081 7.77 11.65 BTU\h 45934 64308

0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS printed on 6 Page 11/2/2009

0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS

Duct Flow Calculator
Formula for Flow of Air at Low Pressures (Kent, Power 1936 p 1-18) 144 283.47525

inches dia length 12 240

feet

mm

19

20

Duct dia inches 12 12 19 19

Duct length feet 20 60 20 60

Flow (cfm)@Depressurization .04 inches H20 (10 Pa) 1170 676 3864 2231

in H20 Pa 0.019685

5

flow

cfm l/sec 828.6207 402.243

Improved Make-Up Air Supply Techniques p10 Flow Through Ducts of 20m Equivalent Length (L/s) Duct size Pressure Differences (Pa) mm in 5 10 15 75 100 125 150 175 200 225 250 3 <5 4 5 6 7 8 9 10 5 11 22 35 50 75 110 140 7 14 28 45 70 100 140 180

20 9 18 32 54 80 120 150 210

25 10 20 38 60 90 135 180 230

8 15 25 40 55 80 100

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0b1ed4d1-dda5-495b-8a79-952a21e97b3d.XLS

Depressurization .02 in (5 Pa) 828 478 2732 1577

50 14 30 50 85 130 180 250 330

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