Six transport
problems.
A building exchanges heat, light, air and moisture with its climate continuously. These are the six exchanges we work with, each with its own governing quantity, its own dominant transport mechanism, and its own way of going wrong.
Thermal
Heat does not respect drawings. It moves through whatever you build, at a rate the assembly decides.
Conduction · Convection · Radiation02IrradianceG — W/m² · SHGC — 0…1Solar
The sun is the largest thermal event in the life of a building, and it arrives on a schedule you can calculate.
Shortwave radiation03Pressure and flowu — m/s · ACH — 1/hAir
Air is the fastest way to move energy into or out of a building, and the hardest to draw.
Advection04Vapour pressurep — Pa · RH — %Moisture
Moisture moves slowly, invisibly, and it is the failure mode that outlives everyone on the project.
Diffusion · Capillarity05IlluminanceE — lux · DF — %Daylight
Daylight is the only building service that is free, variable, and impossible to retrofit.
Visible radiation06DemandQ — kWh/m²aEnergy
Energy is not a discipline of its own. It is the arithmetic left over once the other five have been decided.
Balance