Result
Preliminary calculation: This tool is for quick sizing and information. In real projects, load calculation, selection and commissioning require engineering calculations and a site survey. Results are approximate values.
Formulas
Q_sensible [W] = ρ·cp·V̇/3600 × ΔT ≈ 0.335 × V̇ [m³/h] × ΔT [K]Q_latent [W] ≈ 0.834 × V̇ [m³/h] × Δw [g/kg]In systems that take in fresh air (air handling units, rooftop units), a significant part of the load comes from fresh air. In humid climates the latent load grows; that is why looking only at temperature difference leads to incomplete calculations.
- To remove moisture on a cooling coil, the surface temperature must fall below the dew point
- If SHR is low (high moisture load), a larger capacity is selected
- In heating, the latent load is taken as zero if there is no humidification
- At high altitude air density drops, so a flow correction is needed
Frequently asked questions
What are sensible and latent heat?
Sensible heat changes the air temperature; latent heat changes the moisture content (condensation and evaporation).
Where do I find the humidity difference (Δw)?
You can calculate the humidity ratio of the inlet and outlet conditions with the psychrometrics tool and take the difference.
What does SHR mean?
The sensible heat ratio is the share of sensible heat in the total load. In comfort applications it is generally around 0.7–0.8.