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Darcy vs Fanning Friction Factors: Catch the Fourfold Pipe-Loss Error
Mixing a Fanning factor with a Darcy equation changes straight-pipe friction loss fourfold. Check the coefficient convention before adjusting roughness or pump head.
15 hours ago5 min read
Chiller IPLV vs Annual Plant Energy: Rebuild the Site Load-Bin Calculation
IPLV compares chiller performance at prescribed rating conditions. Annual plant electricity needs site loads, coincident conditions, operating hours and auxiliary energy.
15 hours ago5 min read
Pump-Curve Interpolation: Stay Within the Selected Impeller Diameter and Catalog Points
A spreadsheet can produce a smooth pump curve from the wrong points. Lock the model, impeller and speed first, then interpolate only inside a documented interval.
15 hours ago5 min read
Hydronic Balancing-Valve Flow Readings: How Differential-Pressure Uncertainty Changes the Result
A stable flow display can conceal a weak differential-pressure signal. Calculate the pressure-only bounds, then account for the valve setting, coefficient and fluid.
15 hours ago4 min read
Fan Static vs Total Efficiency: Put Outlet Velocity Pressure on the Same Boundary
A fan can have 72% total efficiency and 64.5% static efficiency at the same operating point. The difference can be pressure accounting, with no change in fan performance.
15 hours ago4 min read
Internally Lined Ducts: Recalculate Clear Area Before Pressure Loss
Adding 25 mm lining to an 800 × 500 mm metal opening removes 15.6% of its air area. At unchanged airflow, the effect on velocity pressure is much larger.
15 hours ago5 min read
AHU Plantroom Space Planning: Add Coil-Pull and Filter-Withdrawal Envelopes
An AHU can fit inside a plantroom while its filters and cooling coil cannot come out. Coordinate the moving component, service task and exit route as separate spaces.
15 hours ago5 min read
Chilled Water System Design Handbook: From Load to Commissioning
Explore Nexora’s 261-page chilled-water design handbook: 30 chapters covering chillers, piping, pumps, controls, worked examples and commissioning.
Sep 204 min read
HVAC Beginner’s Guide: From First Principles to Real-World Design
New to HVAC? Follow a clear roadmap from heat transfer and psychrometrics to cooling loads, equipment, ductwork, controls and commissioning.
Sep 176 min read
Ductless vs. Ducted: How Jet Fan Systems and CFD Modeling Are Reshaping Basement Clearance
Jet fan systems can reduce distributed ductwork and protect basement headroom—but only when extract, makeup air, controls and CFD verification are designed as one coordinated system.
Sep 119 min read
How to Size a Chilled Water Fan Coil Unit (FCU)
Learn the essential steps for sizing a chilled water fan coil unit, including cooling load, airflow, chilled-water flow, external static pressure and final manufacturer selection.
Aug 244 min read
Chilled Water Pump System Design Guidance
Learn how to design a chilled water pump system—from calculating water flow and pipe pressure losses to determining pump head, selecting the correct pump and planning efficient controls. Avoid common design mistakes and discover practical Nexora tools that make HVAC calculations faster and easier.
Aug 245 min read
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