What this tool does
Keeps permeate demand, rated production, availability, membrane recovery, peak draw and reject routing visible as separate quantities.
When to use it
Use with current measured spot-free rinse use and current membrane production at actual feed conditions.
Inputs and supported units
Each labelled field explains the quantity it expects. Unit-system changes convert existing numeric entries once and keep calculations on a single SI internal basis. Supported shared units include L/min and GPM, metres and feet, kPa and psi, millimetres and inches, kW and hp, and °C and °F as relevant.
Calculation or decision method
Feed = permeate / recovery; reject = feed − permeate
How to interpret the result
Read the primary result with the supporting breakdown and warning. A plausible number is not evidence that every input, operating case or design constraint has been included.
Worked example
At 15 L spot-free rinse for 120 vehicles, demand is 1,800 L/day. A 120 L/h unit running 18 hours at 90% availability makes 1,944 L/day before peak-storage checks.
Assumptions
Steady representative operating periods; user-entered meter, equipment, tariff and operating data; volumes are quantity balances rather than water-quality claims.
Limitations
No treatment technology, discharge route, oil-water separation, chemical compatibility, permit condition or manufacturer package is selected or approved.
Sources
- U.S. EPA WaterSense at Work — Vehicle Washes
- U.S. Department of Energy — Vehicle Wash Water-Use Estimating Methods
- International Carwash Association — Water Use, Evaporation and Carryout
- U.S. Department of Energy — Handbook of Water Use and Conservation