Engineering Tools

10 Simple Engineering Calculators

Quick calculators for water treatment, cooling towers, boilers and RO. Use them for estimates and always verify the final result against site data and approved operating limits.

01Chemical Dosingppm → kg/hr & L/hr 02Cooling Tower BlowdownEvaporation, drift & COC 03Cycles of ConcentrationConductivity ratio 04RO RecoveryFeed, permeate & concentrate 05RO Salt RejectionFeed vs permeate TDS 06Boiler BlowdownSteam & TDS balance 07NaOCl DosingChlorine dose → pump rate 08HCl DosingPure acid dose → solution rate 09Tank VolumeRectangular & cylindrical 10Flow Converterm³/hr, L/min & US gpm

Chemical Dosing CalculatorGeneral liquid chemical dosing from ppm

Water flow m³/hr Required dose ppm / mg/L Product concentration % w/w Product density kg/L Operating hours hr/day Operating days days/month

Pure chemical—

Commercial product—

Dosing rate—

Daily volume—

Monthly volume—

Suggested pump size (+25%)—

Use the actual concentration and density from the current product SDS/TDS. Pump selection must also consider discharge pressure, turndown and material compatibility.

Cooling Tower Blowdown CalculatorSteady-state water balance

Evaporation loss m³/hr Drift loss m³/hr Cycles of concentration COC

Required blowdown—

Required make-up—

Blowdown per day—

Formula: Blowdown = Evaporation ÷ (COC − 1) − Drift. Add any significant leakage, splash-out or filter-discharge losses separately.

Cycles of Concentration CalculatorConductivity-based estimate

Make-up conductivity µS/cm Circulating conductivity µS/cm

Estimated cycles—

Conductivity COC is a useful operational estimate. Precipitation, chemical addition or contamination can make individual ions behave differently.

RO Recovery CalculatorFeed, permeate and concentrate flow

RO feed flow m³/hr Permeate flow m³/hr

Recovery—

Concentrate flow—

RO Salt Rejection CalculatorFeed TDS versus permeate TDS

Feed TDS mg/L Permeate TDS mg/L

Salt rejection—

Salt passage—

Boiler Blowdown CalculatorSteam rate and TDS mass balance

Steam generation kg/hr Feedwater TDS mg/L Boiler-water TDS mg/L

Blowdown flow—

Approx. blowdown volume—

Feedwater flow—

Blowdown % of feedwater—

This simplified balance assumes negligible dissolved solids in steam. Boiler-water limits must come from the OEM/treatment program for the actual pressure and steam-quality requirements.

Sodium Hypochlorite Dosing CalculatorAvailable chlorine dose to solution pump rate

Water flow m³/hr Required chlorine dose mg/L NaOCl product strength % w/w Product density kg/L

Active requirement—

Product requirement—

Pump rate—

Daily volume—

Product strength can decay during storage. Use current certificate/SDS/TDS data and keep hypochlorite segregated from acids and incompatible chemicals.

Hydrochloric Acid Dosing CalculatorPure HCl target to commercial solution rate

Water flow m³/hr Required pure HCl dose mg/L HCl concentration % w/w Product density kg/L

Pure HCl requirement—

Commercial HCl—

Pump rate—

Daily volume—

For pH control, the required acid dose depends on alkalinity and buffering—not pH alone. Never mix HCl with hypochlorite/chlorine products.

Tank Volume CalculatorRectangular or vertical cylindrical tank

Tank shape type

Length m Width m

Liquid height m

Liquid volume—

Water Flow Unit Converterm³/hr, L/min and US gpm

Flow value input Input unit unit

m³/hr—

L/min—

US gpm—

m³/day—

Engineering note

These tools are intended for quick engineering estimates and learning. Final chemical doses, water-quality limits and equipment selections must be checked against actual analysis, OEM requirements, supplier data and approved plant procedures.