Free Engineering Simulation Tutorial - Opensource Software & Simulation Guides

Fan and blower power is one of the most frequently mis-estimated quantities in HVAC and industrial ventilation design. Confusing air power with shaft power, mixing static pressure with total efficiency, or forgetting motor and belt losses can produce an error of 30–50 % in the predicted electrical demand — which propagates straight into your energy model, your operating-cost estimate and your motor selection. This page gives you a rigorous treatment of the fan power equation together with a free online Fan / Blower Power Calculator that computes air power, shaft (brake) power and motor input power in any unit system, and reports annual energy and cost. Figure 1 Fan/Blower Power Calculation working steps It pairs naturally with the site's CFM Calculator and Duct Sizing Calculator : size the duct, obtain the system pressure drop, then bring the airflow and pressure here to size the fan and its motor. Contents The fan power calculator Governing eq...

Undersize a duct and the system roars like a jet engine while the far rooms never get warm; oversize it and you waste money and space. Duct sizing is where good HVAC design is won or lost, and the most widely used approach — the one behind ACCA Manual D and most residential systems — is the equal-friction method . This guide gives you a professional-grade duct sizing calculator (validated against ACCA/ASHRAE formulas) that converts CFM into round and rectangular duct sizes , checks the velocity, and explains the method behind every number. Figure 1. In the equal-friction method, every duct section is sized to the same friction rate (e.g. 0.08 in.wg/100 ft). As CFM drops after each branch, the duct steps down — and the system stays balanced. Table of Contents The Duct Sizing Calculator What Is the Equal-Friction Method? The Sizing Formulas Choosing a Friction Rate Velocity Limits (Noise Control) Round to Rectangular Conversion Step...

Choose the wrong fan and you will feel it every day — a bathroom that stays damp, a kitchen full of lingering smells, a stuffy office, or an air conditioner that runs forever and never quite cools. The number that prevents all of this is CFM — cubic feet per minute, the amount of air a device moves. This guide explains exactly how to calculate CFM for exhaust fans, duct and inline fans, air conditioners, kitchen hoods and whole-house ventilation , and gives you a free multi-mode CFM calculator (validated against ASHRAE and SMACNA references) to size any device in seconds. Figure 1. CFM measures how much air a device moves each minute. The same idea sizes an exhaust fan, an inline duct fan, an air conditioner blower or a kitchen hood — only the required rate changes. Table of Contents The CFM Calculator (5 Modes) What Is CFM? The 3 Core CFM Formulas Recommended Air Changes per Hour (ACH) CFM by Device Type Static Pressure: Why Real CFM...