TOOL GUIDE
Cooling load → air / water flow
Convert cooling load into supply airflow from sensible load and water flow from total load.
Purpose & scope
Convert cooling load into supply airflow from sensible load and water flow from total load.
Simple energy balance; does not simulate coils, dehumidification, bypass or equipment selection.
Inputs
Use drawings, design conditions and manufacturer data. Units and example values follow the calculator; example values are not universal design requirements.
| Parameter | Value / interpretation |
|---|---|
| Total cooling capacity | Total cooling load from a load calculation or design condition. |
| Capacity unit | kW / BTU/h / TR (refrigeration ton) |
| Sensible load fraction · % | Sensible fraction of total load, used for the supply-air calculation. |
| Room − supply air temperature difference · K | Room temperature minus supply-air temperature; positive for cooling. |
| Air density · kg/m³ | Air density at design conditions. |
| Air specific heat · kJ/(kg·K) | Air specific heat capacity, used with sensible load. |
| Return − supply water temperature difference · K | Return-water minus supply-water temperature for water-side heat transfer. |
| Mean water temperature · °C | Mean water temperature used to determine density. |
| Water specific heat · kJ/(kg·K) | Water specific heat capacity; do not assume the same value for glycol. |
Steps
- Enter total load and select kW, BTU/h or TR.
- Enter SHR, air/water temperature differences and fluid properties.
- Read results and transfer inputs to duct/pipe sizing; check the receiving tool’s limits.
Worked example
This reproducible training example uses the values below. Select the appropriate mode and overwrite restored project values. Example rates, K values and equipment losses are assumptions, not mandatory design criteria.
Examples use a decimal point and no thousands separator.
All example inputs
| Parameter | Value / interpretation |
|---|---|
| Total cooling capacity | 10 |
| Capacity unit | kW |
| Sensible load fraction | 75 % |
| Room − supply air temperature difference | 10 K |
| Air density | 1.2 kg/m³ |
| Air specific heat | 1.006 kJ/(kg·K) |
| Return − supply water temperature difference | 5 K |
| Mean water temperature | 9.5 °C |
| Water specific heat | 4.186 kJ/(kg·K) |
Expected results (rounded)
| Parameter | Value / interpretation |
|---|---|
| Supply airflow | 2236.58 m³/h |
| Chilled-water flow | 1.72 m³/h |
Small differences in displayed rounding are normal. A result that passes the entered limits does not establish suitability for the complete system.
Method & limitations
Simple energy balance; does not simulate coils, dehumidification, bypass or equipment selection.
Supply airflow uses sensible load: V = Q sensible/(ρ·cp·ΔT). Chilled water flow uses total load: V = Q total/(ρ·cp·ΔT).
Supply airflow is not outdoor ventilation airflow. Check dehumidification and coil duty with air states. Pure-water density; no automatic glycol concentration correction.
Common mistakes
Using total rather than sensible load for air; zero temperature difference; confusing refrigeration tons with mass tonnes.
Projects & reports
- Choose or create an engineering project and enter your actual design inputs.
- Project inputs/results are autosaved in this browser. Where a saved-list panel is available, name and add the selected section or alternative to compare multiple options.
- Review the report before exporting PDF. In the print dialog select Save as PDF. Export JSON for backup and use Open file to restore it; PDF cannot restore project data.
Saved results do not automatically recalculate when another tool changes. Review any dependency warning, recalculate and update the affected results.
References & related tools
Caleffi — Basic hydronic circuit
The tool implements the methods and limits stated above; linking a standard does not establish complete compliance with that standard.