showing
Whole team
points
102,400
spent
$71,856
kWh/day
7.11
scan
0%

Mechanical

Meet the needs of a family of five with as little maintenance and as much comfort as possible.

7,050 galof rain stored in the berm
3 x 9kBtu/h mini-split zones
1,005 galprecast septic tank
7.11kWh a day for all of it

Budget: $71,856 of $45,000, $26,856 over. Power: 7.11 of 6 kWh a day.

Daniel Boyce Team lead

Mechanical lead. Heating and hot water

Hands-on mechanical design, CNC machining, and years of fixing vehicles.

18,900Btu per °F in the slab
4solar thermal collectors
$6,696and 2.46 kWh a day
  • Split the work: Ethan on HVAC, Erick on water supply, Noah on septic.
  • Designed the heat: a water-jacket wood stove pushing glycol through PEX loops in the slab.
  • Turned the slab into a battery: about 18,900 Btu per °F of storage, so one hour of fire holds 65°F for ten hours.
  • Preheats water with four Sunbank flat-plate collectors before a 60 gal tank, with the stove as a second source.
  • Built in two circulation pumps and fail-safe valves, then redrew the whole system the night the Revit model was wiped.

In the chatDang we can make our air conditioner a lot smaller

Redrew his entire hydronic system after the mechanical model was wiped, the night before drawings were due.

CodesIRC Ch. 20, 21, 23, 28, 29

Noah Hatcher

Waste removal and septic

Septic cleaning, construction, and lawn care that taught him soil.

1,005gal tank
1,020sq ft leach field
0kWh a day
  • Chose a gravity-fed septic system that uses no power at all.
  • Specified a 1,005 gal precast tank (700 and 305 gal chambers) from Grove Concrete & Supply.
  • Sized the leach field to Illinois code for Rozetta silt loam: 36 in chambers over about 1,020 sq ft.
  • Ran 4 in Schedule 40 drains and a 3 in vent stack, and kept the sewer 50 ft from the cisterns.
  • Added an effluent filter and a high-water alarm on its own 48 V circuit.
  • Drew the floor plans and rolled the mechanical model back after it was deleted.

In the chatWe did it boys!!! Under budget BABY!!!

Restored everyone's pipes by rolling the model back to just before the deletion.

Codes77 Ill. Adm. Code 890 and 905, IPC, UPC

Erick Lund

Water supply and distribution

Had already built a rainwater system for a chicken coop.

7,050gal stored
127.7gal a day used
42.06in of rain a year
  • Proved rain alone could supply the house: 127.7 gal a day with efficient fixtures, against 12,300 gal a month for a typical family of five.
  • Specified two 3,525 gal cisterns buried in the berm below the frost line.
  • Laid out the treatment train: gutter guards, 60 micron filters, a floating intake, 5 micron filtration and UV.
  • Sized a 1/2 HP pump and 32 gal pressure tank, with a hand pump in parallel.
  • Planned a 3,500 gal starter delivery to carry the dry first quarter.
  • Worked through Illinois water law and asked for the county and state calls.

In the chatI think the one we need permission from is IDPH since it's restricted by a state law not just code

The county's written approval landed, and the cisterns stayed.

Codes77 Ill. Adm. Code 890, 900, 930, NSF 61

Ethan Patterson

HVAC and exhaust

Works in the HVAC department at Pensacola Christian College.

3 x 9kBtu/h
1.95kWh a day cooling
$7,840installed
  • Chose three EG4 9k mini-splits: master suite, main room, and the two bedrooms.
  • Fit a power curve to the spec sheet and ran a 105°F worst day hour by hour.
  • Averaged cooling at 1.95 kWh a day across the year.
  • Specified 80 CFM bath fans and a 110 CFM kitchen fan, ducted out the roof.
  • Designed a hydronic cooling alternative with a 750 ft ground loop, then dropped it when the real heat loss came in.

In the chatPipes in the ceilings is bad because our dead load will be crazy high

Learned the units quit near 5°F outside, so the wood stove stayed primary heat.

CodesIRC Ch. 15, IRC M1401

What made it in, and what got cut.

  • Wood stove with a water jacketFeeds PEX loops in the slab. One hour of fire holds 65°F for about ten hours.
  • Three 9k mini-splitsDuctless, zoned and quiet. They also keep a vacant house at 60°F with no fire.
  • Solar, wood and electric water heatingThe 60 gal tank doubles as a thermal battery for spare power.
  • Rainwater instead of a wellLeaves the aquifer alone. County and state signed off.
  • Gravity septic instead of compostingZero power, and every installer already knows how to build it.
  • Hydronic slab cooling and a 750 ft ground loopDropped once the corrected heat loss came in far lower.
  • Drilled wellPump power, drilling cost, and nearby park wells only reach 50 to 150 ft.
  • Swamp coolerIllinois summers are too humid.
  • Heat pump water heaterAbout five times the price.
  • Composting toiletsNot practical for a family of five.

January through March run dry. A 3,500 gallon delivery at move-in carries it. NOAA rainfall for Virginia, Illinois, falling on 2,250 sq ft of roof, against 127.7 gallons a day.

Rain collected (average year)Family usegallons per month

0k1.75k3.5k5.25k7kJanFebMarAprMayJunJulAugSepOctNovDec
Table
MonthRain collected (average year)Family use
Jan2,3953,831
Feb2,6043,831
Mar3,4643,831
Apr4,9763,831
May5,6963,831
Jun6,2543,831
Jul4,9413,831
Aug3,9643,831
Sep4,3713,831
Oct3,9643,831
Nov2,9993,831
Dec3,2673,831

If one thing fails, something else picks it up.

  • Hand pump fills the pressure tank if the electric pump dies
  • Two hydronic circulation pumps
  • Fail-open and fail-closed valves on the water heating
  • Septic high-water alarm on its own 48 V circuit, plus an effluent filter
  • Mini-splits as backup heat
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