Calculations & sizing
Sizing you can defend in a design review.
Calculations run against recognised standards and first-principles hydraulics, on the connected network you drew. Every result traces back to the elements that produced it, so a number in a schedule can always be explained.
Hydraulics
Flow, friction and pressure drop.
- Darcy–Weisbach — pressure drop with Colebrook–White friction factors across laminar and turbulent regimes.
- Duct auto-sizing — iterative sizing along a run until the pressure gradient meets your target, with tee, bend and terminal losses included.
- Pipe sizing — loading units converted to design flow, then friction and gravity pressure drop resolved leg by leg.
- Index runs — the critical route through a network, reported with accumulated pressure drop and a network summary.
- Hot-water return — circulation heat losses, spine bucketing, and a pump head of spine friction plus the worst branch.
- Drainage — discharge units accumulated per branch and converted by Q = K × √(ΣDU), with stack assignment.
- Refrigerant — copper line sizing with refrigerant property data, mass flow and pressure drop.
Loads and environment
What the systems have to deal with.
EnergyPlus loads
Design-day heating and cooling loads through the EnergyPlus engine, with model geometry, constructions and presets driven from the project.
Preliminary AC loads
Faster cooling-load estimates per space by level, for early-stage sizing and plant allowance.
Psychrometrics
An AHU calculator working the psychrometric process through, with results saved and printed.
Hot-water storage
First-principles storage draw-off curves for cylinder sizing, plus a reservoir-emptying peak calculator.
Illuminance
Normal and emergency lux levels per space, by luminaire type and space occupancy.
Space data
Occupancy densities and construction thermal properties feeding the calculations that need them.
Seeing the result
Numbers you can interrogate.
Heat map
Rule-based conditional colouring of paths and terminals by pressure drop, so a struggling system is visible on the canvas.
Network schematic
A topology map of a connected network, with pan and zoom to any element in it.
Checks
Connection checks, missing-label reports, orphaned elements and network elevation consistency.
Live or deferred
Calculations can follow every edit, or be held until you ask for them on a large model.
Related
Where to look next.
See it on your own project.
engiCAD is in active development and we are onboarding a small number of practices. Tell us what you work on and we will arrange a walkthrough against a drawing you recognise.