Engineering Hub
Free calculators and reference tools for HVAC, refrigeration, and mechanical engineers. Cable sizing to BS 7671, unit conversion, mass flow rates, cooling tower evaluation, thread dimensions, and more — no login required, built by engineers for engineers.
Cable Sizing Calculator
Calculate cable cross-section, voltage drop, and breaker sizing for heat pump installations. BS 7671 / IEC 60364 compliant with derating factors for ambient temperature and installation method.
Launch CalculatorUnit Converter
Instant conversion between imperial and metric units: GPM to L/s, PSI to Bar, BTU to kW, pipe DN to NPS, and temperature scales. Real-time bidirectional conversion as you type.
Launch ConverterMass Flow Rate & Pump Sizing
Calculate required pump flow rates (L/s, m³/h) and pressure drops for hydronic heating and cooling systems. Input your thermal load to get precise pipe and pump specifications.
Launch CalculatorCooling Tower Evaluator
Evaluate cooling tower performance and feed water requirements. Input wet bulb temperature, approach, and range to size your cooling tower for optimal efficiency.
Launch Evaluator Coming SoonSteam Boiler Replacement ROI
Calculate the exact thermal and financial impact of replacing your steam boiler with an R290 or CO² heat pump. See payback period, annual savings, and carbon reduction.
Launch Calculator Coming SoonRefrigerant & Oil Charge
Calculate precise oil and refrigerant charges based on system pipe length, diameter, and component volume. Essential for commissioning and servicing heat pump systems.
Launch Calculator Coming SoonCold Room Load Estimator
Input room dimensions, insulation values, product load, and target temperature to calculate the required kW cooling capacity for cold rooms and freezer stores.
Launch Calculator Coming SoonThread Dimension Reference
Searchable database covering DIN, GOST, BSP, NPT, Metric, JIS, ISO, ANSI, and AFBMA thread standards. Instantly look up pitch, major/minor diameters, and tapping drill sizes.
Launch ReferencePinch Analysis Tool
Identify optimal heat recovery targets in industrial processes. Input your hot and cold stream data to find the pinch point and maximum energy recovery potential.
Launch Tool Coming SoonFrequently Asked Questions
What engineering tools are available in the Karnot Engineering Hub?
The Karnot Engineering Hub provides free calculators including electrical cable sizing (BS 7671/IEC 60364), imperial-to-metric unit conversion, mass flow rate and pump sizing, cooling tower evaluation, refrigerant oil charge calculation, thread dimension reference, and cold room load estimation.
Are these engineering calculators free to use?
Yes, all calculators in the Karnot Engineering Hub are completely free with no login required. They are built by our engineering team to help HVAC, refrigeration, and mechanical professionals with daily calculations.
What standards do the calculators follow?
Our calculators follow international standards including BS 7671 (IET Wiring Regulations), IEC 60364, and use industry-standard lookup tables for cable ratings, derating factors, and thread dimensions from DIN, ISO, BSP, NPT, JIS, and ANSI specifications.
Can I use these calculators for heat pump installations?
Absolutely. The cable sizing calculator includes quick-select buttons for common Karnot heat pump power ratings (9.5kW to 100kW), and the unit converter covers all flow, pressure, energy, and temperature conversions needed for heat pump system design.
Need Custom Engineering Support?
Our engineering team can provide bespoke sizing, system design, and commissioning support for your heat pump project.