Formula used
Pressure-drop and geometry results are preliminary engineering estimates. Confirm final selections with certified manufacturer data.
How to use this calculator
- Select the coil type and calculation method.
- Enter airflow and entering air conditions.
- Define the required leaving air state.
- Enter fluid temperatures and design pressure limits.
- Add existing geometry when checking a selected coil.
- Submit the form and review every warning.
- Compare alternatives before requesting manufacturer selections.
- Export the calculation for design documentation.
Example design data
| Application | Airflow | Entering air | Leaving air | Fluid temperatures | Typical limit |
|---|---|---|---|---|---|
| Comfort cooling | 2.5 m³/s | 30°C, 55% RH | 14°C, 90% RH | 7°C to 12°C water | 2.5 m/s face velocity |
| Hot-water heating | 1.8 m³/s | 10°C, 60% RH | 32°C, same humidity ratio | 80°C to 60°C water | 150 Pa air drop |
| Low-temperature glycol | 3.2 m³/s | 24°C, 50% RH | 8°C, 92% RH | -2°C to 4°C glycol | 2.0 m/s fluid velocity |
Frequently asked questions
What does a coil selection calculator estimate?
It estimates capacity, geometry, flow, and pressure losses. It also checks psychrometric air changes. Final equipment should use certified manufacturer selection data.
Which humidity input should I use?
Use the condition available from your design documents. Relative humidity is usually simplest. Wet bulb often improves cooling-load definition for engineers.
Why can total capacity exceed sensible capacity?
Cooling coils can remove both heat and moisture. Moisture removal creates a latent cooling load. Their sum produces the total required coil capacity.
How is required water flow calculated?
The calculator applies a fluid energy balance. Flow depends on capacity and fluid temperature change. Glycol properties adjust density and specific heat automatically.
What is coil face velocity?
Face velocity divides airflow by coil face area. Excessive velocity increases pressure and carryover risk. Lower velocity usually needs a physically larger coil.
What does the bypass factor mean?
Bypass factor represents incomplete contact with the coil. Smaller values indicate stronger air treatment. It supports apparatus dew-point and dehumidification checks.
Why does glycol increase pressure drop?
Glycol solutions normally have higher viscosity than water. Higher viscosity increases hydraulic resistance. Concentration and temperature strongly affect the final result.
Can this calculator select DX coils?
It estimates DX duty and refrigerant mass flow. Detailed circuitry needs refrigerant-specific performance maps. Use compressor and manufacturer data before ordering equipment.
Are the pressure-drop estimates exact?
No, they use simplified engineering correlations. Actual fins, headers, and circuits change resistance. Verify final losses using certified coil performance software.