Heating, cooling and ventilation design: loads, ducts, pipes, AHUs, pumps and ventilation rules.
Twelve duct design mistakes that leave systems noisy, short of air or expensive to run, from skipping the index run to flat rectangular ducts and unspecified leakage, with what to do instead.
12 Common Duct Design Mistakes Read More »
How to design condensate traps and drains for AHUs, fan coils and cassettes: seal height from the drain pan pressure, plinth height, falls, air breaks, condensate quantities and pump interlocks.
Condensate Drain Trap Design for AHUs and FCUs Read More »
A fast, defensible way to estimate the head of a closed chilled water pump from the index circuit, with typical component losses, a worked 900 kW example at 229 kPa and the mistakes that oversize pumps.
Chilled Water Pump Head: A Quick Estimate Read More »
A quick first design for jet fan car park ventilation: total airflow by area rate or air changes, jet fan thrust and airflow, spacing and count, gas sensing and fire-mode pointers, worked for a 5000 m² basement.
Car Park Ventilation with Jet Fans: Quick Design Read More »
How ASHRAE 62.1 and EN 16798-1 set outdoor air rates, side by side, with the same 400 m² office calculated under both (220–275 L/s vs 560 L/s) and what the difference means on a project.
ASHRAE 62.1 vs EN 16798: Ventilation Rates Compared Read More »
Quick rules to size an air handling unit before the selection software is open: airflow from the sensible load, casing and coil velocities, coil and fan duties and the plant room space, with a worked 2.0 m³/s DOAS example.
AHU Sizing: Quick Rules for Airflow, Coil and Footprint Read More »
A practical guide to the psychrometric chart for air handling unit design: reading the seven properties, the room SHR line, mixing, coil ADP and bypass factor, fan heat, humidification and a full summer worked example.
Psychrometric Chart for AHU Design: Mixing, Coils and Reheat Read More »
How to size hydronic heating pipes: water flow from load and temperature difference, velocity and Pa/m criteria, Darcy–Weisbach friction, a worked 200 kW main, and the index circuit that sets the pump head.
Heating Pipe Sizing: Flow, Velocity, Pa/m and Pump Head Read More »
A practical, step-by-step EN 12831 heat loss calculation: design conditions, U-values, thermal bridges, ground and unheated spaces, ventilation, and one living room calculated in full to 904 W.
Heat Loss Calculation Step by Step: EN 12831 Worked Example Read More »
How to size supply ducts with the equal friction method, check velocities for noise, count fitting losses and calculate the index run that selects the fan, with a fully worked office floor branch.
Duct Sizing Guide: Equal Friction, Fittings and the Index Run Read More »