Hydronic Loop Builder
HydronicDrop equipment on an elevation, click port-to-port to lay pipe, and hit run — the loop solves a real steady-state hydraulic and thermal balance every tick, so flow finds its operating point and water temperature propagates around the circuit. New to the ideas? Start with Hydronic Loops, Load Piping, and Hydronic Balancing.
Desktop tool
Dragging equipment around an elevation and clicking port-to-port to run pipe wants a pointer and a wide canvas — open this on a laptop or desktop to build and run a loop. A finger can't both drag a component and pan the sheet, so it's pointer-only by design. The mental model it teaches:
- A loop finds one operating point. The pump curve and the system's resistance meet at a single flow — open a valve and the whole loop's flow shifts, not just one branch.
- Two-way valves throttle; three-way valves divert. A two-way valve changes total loop flow; a three-way holds pump flow roughly constant and sends the rest down a bypass.
- Parallel branches need balancing. The low-resistance branch hogs the flow; a balance valve adds resistance to even the split.
- Heat rides the water. q = 500 · GPM · ΔT — drop the flow and ΔT climbs. Watch a cold loop warm up over a few seconds as the plant's heat transports around.
- Up is elevation. A pipe drawn vertically is a real height — static head, ready for open-system work.
New to hydronics? Hydronic Loops covers the same ideas and reads fine on a phone.
How it works
Every tick the builder flattens your layout into a network — pipes and equipment become flow branches between pressure nodes — and solves a linearized nodal balance: mass is conserved at every junction, head drops across each resistance as k·Q², and the pump adds head on its curve H = (H₀ − a·Q²)·(speed/100)². Flow settles to the operating point in a few iterations.
Then a thermal sweep transports temperature on those flows — q = 500 · GPM · ΔT at each coil, flow-weighted mixing at each tee. A loop reads its upstream temperature from the previous tick, so a cold loop warms up over a couple of seconds the way a real one does.
A teaching model, not a design tool: it solves a steady-state balance each tick in canonical US units (GPM, ft of head, °F) and rounds at the display. Pipe friction is a small nominal value; closed valves are a large finite resistance, never infinite — so the math always stays finite.