| SHCS Calculator SHCS Calculator | | | |
| Please fill in ALL the placeholder numbers (in Bold) and read the result (in the BLUE Italized CELLS) | | |
| First calculate | volume of air in the greenhouse - fill in the figures in the Greenhouse Dimensions Yellow section | | |
| Then fill in the fan, tubing & cost data in the green cells | Your Calculated figures are in italics | Data Entry Points are in bold, change any or all. | Don't change the italized formula cells!!! | Ideal Design Numbers should be: 5 air exchanges per hour and 2-4 feet per sec air speed in the air circulation tubing | | |
| Your important Calculated figures are in cells this color | | | |
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| DIRECT YOUR QUESTIONS TO THE SHCS FORUM | | |
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| STEP ONE Greenhouse Dimensions STEP ONE Greenhouse Dimensions | | | Enter a zero in cells that do not apply! BTW, a half circle hoop house has an 180 degree included arc |
| Box Sections Box Sections | Height | Length | Width | Box Section Sub total CUFT Box Section Sub total CUFT | Hoop Sections | Arc Included | Radius | Length | Hoop Section Sub Total CUFT |
| Main | 4 | 21 | 11 | 924 | Main | | | | |
| Section2 | 4 | 22 | 4 | 352 | Section2 | | | | |
| Section3 | 7 | 22 | 4 | =b9*c9*d9 616 | Section3 | | | | |
| Total Square footage | 407 | Design should be 1.33 feet of tubing per square foot | 541.3100000000001 | | You can get more precise figures for your Hoop Section Volumes from here. Remember to zero out or clear the contents of calculator cells above if you use that other calculator - place the figure you get in the next cell over (just above the calculated value for "Total Hoop Volume CU/ft" - it should be blank before you add the figure from the other calculator) | |
| Total GH Air Volume | 1892 | | Total Box Section CUFT | 1892 | | | | Total Hoop Section CU/FT | |
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| STEP TWO Fans | NB: From the calculated CFM, choose the CFM for the fan you have in mind and enter it (for 0.02" back pressure if you that figure from the manufacturer's data sheet) | | |
| Number of Fans | Exchange Rate TIMES/HOUR Design | Fan CFM Calculated | Fan CFM from Manufacturer List | Exchange Rate TIMES/HOUR Calculated | | | | | |
| 1 | 5 | 157.66666666666666 | 150 | 4.7568710359408035 | | | | | |
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| Underground Air Circulation Tubing Underground Air Circulation Tubing | | | | | | Total Feet of Tubing | Tubing Air Speed FT/SEC | Time in each Tube SEC | |
| Plenums | Tubing Diameter | Effective Diameter | Average Length of tubing | # of tubes in each plenum | Total Tubing Effective Area SQFT | 405 | 2.1740976645435244 | 12.4189453125 | |
| 1 | 4 | 3.75 | 27 | 15 | 1.14990234375 | | | | |
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| Cost of system hardware | | | | | | | | |
| Tubing @ $0.30 per foot | Fans, Plenums, @ approx, $200 per Plenum | Controls Package | Total Hardware Costs | | | | | | |
$840.00 $121.50 | $400.00 $200.00 | 100 $100.00 | 1340 $421.50 | | | | | | |
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| Payback Calculations | | | | | | | | | |
| Mass of heatsink in pounds | 97680 | Heat stored with a 1 F deg rise in heat sink temp | 97680 | Your Therm cost ($ per 100,000 BTU's) go here for rates | 1.55 $1.55 | Stored heat value as natural gas cost per 1 F deg rise | $7.07 $1.51 | Expected # of days you get a 1 F deg Rise | 180 |
| Gas Value gained each year | 636.12 $272.53 | Your Electricity Cost in $/kilowatt hour (rates here) | 0.08 $0.08 | Operating cost - fans @ 2 amps for 8 hrs/day | $53.73 $26.86 | Yearly Net | 367.47999999999996 $245.66 | Hardware Payback in Years | 1.7157636959870262 |
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