A Demi the Drop explainer
Where does the
water go?
A greenhouse full of thirsty plants, and hardly a drop from the town main? Almost. Let a drop of water explain her two favorite tricks.
Follow the drop ↓
A greenhouse full of thirsty plants, and hardly a drop from the town main? Almost. Let a drop of water explain her two favorite tricks.
Follow the drop ↓My day job is carrying warmth around the heating loop — a sealed circle of pipe. Here's the part people miss: I never get used up. Not a drop of me. I pick up heat, drop it off at the plants, and run right back for more. Same water, around and around, for years.
I ride her like a bus. A bus that never needs new buses!
The heating circuit is a closed hydronic loop: the same treated water circulates indefinitely between the heat exchanger and the greenhouse's radiant lines. It is not consumed, evaporated, or discharged in normal operation — makeup water is needed only for maintenance. The loop that cools the data center is equally closed, on its own side of the exchanger wall.
Now, the plants do drink real water — that's irrigation, and it's a different job from mine. But look up: every greenhouse wears a giant rain catcher on its head. Rain hits the roof, runs to gutters, and fills the tanks. My billions of cousins, showing up free of charge.
Rain catch = roof area (sq ft) × rainfall (inches) × 0.623 gallons per square foot per inch. At the central-Virginia average of ~43 inches a year: the Pod's 96 sq ft yields ~2,570 gal; the Unit's ~6,500 sq ft yields ~174,000 gal; a flagship Campus greenhouse's ~2.5 acres yields on the order of 2.9 million gallons.† These are design targets before collection losses — real systems capture less than 100% (first-flush diverters, overflow, dry-spell timing), and storage sizing decides how much of a wet month you can bank for a dry one. The full basis lives in the Canonical Water Math sheet at Intelligent Harvest.
So when someone asks “where does the water go?” — ask which water! Heating water (me): sealed loop, never spent, just keeps carrying Jimmy. Irrigation water (my cousins): caught from the roof, sipped by roots through drip lines, and turned into strawberries. The plant doesn't waste much — drip irrigation puts each sip right at the root.
She loops, they get sipped, I get delivered. Everybody's got a lane.
Separating the two systems is what keeps the design honest: the thermal loop's water budget is essentially zero, while the irrigation budget is real and is met first from roof catchment with storage as the buffer. Municipal water remains available as backup — the goal is a greenhouse that sits lightly on the town main, stated as a design target† until a built site meters it.
One water loops forever. The other falls out of the sky onto exactly the roof that needs it. That's the whole trick — and like everything we build, it's a promise with a meter on it.
† Daggered figures are Intelligent Harvest design targets — magnitudes that depend on a built site. Rain math shown uses public climate averages and the standard 0.623 gal/sq ft/inch constant.