eFlow
A single-line diagram editor for datacenter power. Draw the system and the power flow is simulated as you go.
The Curiosity
Electrical single-line diagrams are still mostly drawn in CAD and checked by hand. The drawing knows nothing about the thing it depicts.
What if the diagram itself knew how power flows through it? Drag a UPS onto the canvas, wire it up, open a breaker, and watch every downstream load respond.
The Build
eFlow is a drag-and-drop canvas built on React Flow with thirteen equipment types: utility feed, generator, transformer, UPS, automatic and manual transfer switches, switchgear, circuit breaker, PDU, power meter, server, and a load-profile node.
Power flow is recomputed on every change with a breadth-first propagation from the sources. Loads aggregate upward through the tree, transfer switches pick their live input, and a faulted device blacks out everything that depended on it.
Load profiles are 24-hour curves with IT, cooling, lighting and custom categories. Link one to a piece of equipment and the simulation follows it around the clock.
- Canvas
- React Flow with custom nodes and edges
- Simulation
- Breadth-first power-flow propagation, load aggregation, transfer-switch logic
- Storage
- Browser local storage. Autosave every 30 seconds, JSON import and export
- Runs on
- Desktop browsers. Deliberately not phones
Everything stays on your machine. Nothing is uploaded. Undo, redo, copy, paste and a full set of keyboard shortcuts are there because a diagram editor without them is a toy.
The Result
A working editor and simulator. Free, no account, nothing to install. It is the most engineering-shaped thing in the workshop.
What We Learned
A live simulation makes a drawing honest. Once power flow was computed continuously, topology mistakes that a static diagram would have hidden showed up immediately.
It also confirmed a small rule we keep relearning: some tools should refuse to run on a phone. Saying "desktop only" plainly is kinder than a cramped experience.