Analyze coil contact factor and bypass performance. Check leaving air state against apparatus dew point. Support cleaner HVAC sizing with transparent cooling coil calculations.
Use measured coil conditions to estimate bypass factor, contact factor, cooling load, and condensate rate.
This example shows a typical cooling-coil case. The bypass factor shown is an approximate temperature-method value.
| Scenario | Airflow | Entering DB | Entering RH | Leaving DB | Leaving RH | ADP | Approx. BF | Approx. Contact Factor |
|---|---|---|---|---|---|---|---|---|
| Office AHU cooling coil | 5,000 m³/h | 30.0 °C | 60 % | 14.0 °C | 92 % | 10.0 °C | 0.20 | 0.80 |
BF = (T leaving − T ADP) / (T entering − T ADP)
This is the classic cooling-coil relation based on dry-bulb temperatures.
BF = (W leaving − W ADP) / (W entering − W ADP)
This compares the leaving air state with the saturated state at the apparatus dew point.
BF = (h leaving − h ADP) / (h entering − h ADP)
This method is useful when both sensible and latent cooling effects are important.
Contact Factor = 1 − BFTotal Cooling = ṁ dry air × (h entering − h leaving)Sensible Cooling = ṁ dry air × cp moist air × (T entering − T leaving)Condensate Rate = ṁ dry air × (W entering − W leaving)This calculator converts all inputs internally to SI units, then reports results clearly for both analysis and documentation.
Coil bypass factor is the fraction of air that effectively escapes full contact with the cooling surface. Lower values mean better contact, deeper cooling, and stronger dehumidification across the coil.
Lower is usually better. Many comfort-cooling coils operate in a moderate range, while high-performance coils often target lower values. The best value depends on load, face velocity, coil rows, and dehumidification goals.
Apparatus dew point represents the effective saturated coil-surface condition. It anchors the theoretical end state used in bypass-factor calculations, so an unrealistic ADP will distort both sensible and latent performance estimates.
Each method evaluates bypass factor from a different air-property path. Temperature focuses on sensible change, humidity ratio captures moisture behavior, and enthalpy blends both into a total-energy view.
Measured RH values, uncertain ADP, sensor placement, and rounding can create method spread. A small spread usually indicates consistent field data, while a large spread suggests the measurements need checking.
Yes. Higher face velocity often reduces air-contact time and can increase bypass factor. Coil depth, fin spacing, and airflow uniformity also influence how effectively the air stream approaches the coil surface condition.
In this simplified cooling-coil interpretation, contact factor equals one minus bypass factor and is often used as an effectiveness-style indicator. It shows how strongly the air stream interacts with the coil.
Not directly. This version is structured for cooling-coil analysis using ADP, moisture removal, and bypass-factor relationships. Heating coils follow different air-state behavior and need a separate calculation model.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.