Engineering Calculation & Preliminary Design Platform
Transparent, mathematically rigorous screening and preliminary sizing tools for substation engineers, electrical EPC contractors, HVAC design consultants, and cleanroom facility planners.
33kV / 11kV Substation Transformer Capacity & Fault Sizing
Aggregates maximum demand, applies diversity and expansion margins, selects standard IS 2026 kVA commercial ratings, and computes prospective secondary short-circuit fault levels.
HT/LT Cable Ampacity & Resistive-Inductive Voltage Drop
Calculates full-load current and 3-phase AC voltage drop in XLPE cables. Checks compliance against internal feeder (≤3%) and final branch (≤5%) design limits per NBC / SP 30.
APFC Capacitor Bank kVAR Sizing & Surcharge Screening
Computes required reactive compensation to achieve target power factor (0.99), recommends standard 25/50 kVAR modular steps, and estimates indicative Discom low-PF penalty savings.
Preliminary Industrial DG Set Generator Capacity Estimator
Sizes diesel generator kVA capacity from base linear and motor loads, accounts for starter inrush (DOL, Star-Delta, Soft Starter, VFD), and selects standard OEM ratings (ISO 8528 framework).
Substation Main Earthing Conductor Strip Sizing Tool
Computes adiabatic short-circuit thermal withstand cross-section for Galvanized Iron, Copper, and Aluminum flats. Selects commercial strip sizes with configurable corrosion allowances.
Preliminary HVAC Cooling Load & Tonnage Screening Estimator
Provides preliminary sensible and latent heat load estimates for offices, server rooms, and healthcare facilities. Computes decoupled base/design loads, exact TR, and circulating CFM.
Cleanroom Airflow Rate (ACPH) & Modular HEPA Sizing
Calculates total circulating airflow for ISO Class 5–8 cleanrooms and hospital OTs (NABH). Computes modular H14 HEPA filter counts using physically verified manufacturer ratings.
Equal Friction Duct Sizing & Aspect Ratio Checking Engine
Determines circular equivalent diameter, iteratively solves Huebscher’s equation for rectangular width given restricted ceiling height, and checks aerodynamic aspect ratio (AR ≤ 4:1).
Chilled Water Pipe Hydronic Sizing & Hazen-Williams Head Loss
Calculates chilled water GPM and L/s from chiller tonnage. Selects Schedule 40 NB steel pipe enforcing dual screening criteria (velocity ≤ 8.5 FPS and head loss ≤ 4.0 ft/100ft).
AHU Fan External Static Pressure (ESP) Screening Estimator
Estimates required fan total static head in Pascals, mmWG, and in.wg by aggregating straight duct friction, dynamic fitting allowances, cooling coils, multi-stage filters, and diffusers.
HT/LT Busbar Sizing & Short-Circuit Thermal Stress
Sizes aluminium and copper busbars for continuous ampacity and short-circuit thermal withstand. Calculates peak dynamic electrodynamic forces on supports.
Commercial Rooftop Solar PV Array & Inverter Sizing
Estimates optimum DC solar capacity (kWp), module quantities, on-grid string inverter rating, monthly generation yields, and annual CO2 offsets.
Indoor Lighting Illumination Lux Level & Lumen Method
Calculates required luminaire quantities using zonal cavity RCR and utilization factors. Verifies maintained working-plane Lux and ECBC LPD compliance.
Industrial Induction Motor Starter & Feeder Protection
Computes motor FLA, coordinates Main/Delta/Star contactors for DOL and Star-Delta, sets overload relay bands, and screens backup MCCB ratings.
Battery Bank & Online Industrial UPS Sizing Tool
Sizes battery bank Ah capacity with IEEE 485 aging reserves, determines series/parallel string arrangements, and sizes float chargers and UPS kVA.
Psychrometric Mixed Air & Coil Sensible Heat Ratio (SHR)
Determines mixed air dry-bulb and humidity ratio, total cooling coil tonnage (TR / kW), Sensible Heat Ratio, and hourly moisture condensate drain flow.
Evaporative Cooling Tower Water Loss & Makeup Sizing
Calculates condenser water circulating flow (GPM/m³h), thermal range, approach, evaporation rate, drift loss, blowdown, and daily makeup water (kL/day).
Staircase & Lift Well Pressurization Fan Sizing
Sizes smoke containment pressurization fans (CFM / CMH) based on closed door crack leakage and open door egress velocity. Verifies handle force (≤ 100 N).
Cleanroom Air Shower & Dynamic Pass Box Sizing
Calculates high-velocity nozzle airflow (CFM/CMH), exit scrubbing velocity (≥ 20 m/s), chamber air change sweeps per cycle, and blower motor rating.
Chiller Plant Lifecycle Operating Cost & Payback
Evaluates annual kWh savings, power bill reductions (₹), simple capital payback, and 10-year net financial returns using AHRI 550/590 4-bin part load profiles.
The calculation engines hosted on tools.rsele-hvac.com are intended strictly as preliminary engineering screening and feasibility tools for consulting engineers, MEP contractors, and facility managers. Equipment selections utilize standardized catalog brackets and recognized industrial heuristics. These calculations do not constitute formal stamped engineering designs. Final procurement, electrical safety protection coordination, structural duct reinforcement, hydronic balancing, and statutory utility clearances must be verified by a licensed Chartered Engineer or certified MEP consultant in accordance with local statutory requirements.