How to Calculate H V A C Load
What is H V A C Load?
HVAC load calculation determines heating and cooling requirements. Proper sizing ensures comfort and efficiency without over/under-capacity.
Formula
Total load = sensible + latent
Step-by-Step Guide
- 1Calculate sensible load: Q_s = U×A×ΔT (conduction) plus solar gains and internal loads
- 2Calculate latent load: Q_l = 0.68×CFM×Δh (moisture removal)
- 3Total load = sensible + latent
Worked Examples
Input
Office building 5000 m², design ΔT 8°C, occupancy 500 people
Result
Cooling load ≈ 250-300 kW depending on assumptions
Detailed calculation
Common Mistakes to Avoid
- ✕Under-sizing for future expansion or occupancy increases
- ✕Neglecting solar gains on west-facing windows
Frequently Asked Questions
What are typical cooling loads per area?
Office: 100-150 W/m², retail with solar: 200-300 W/m², industrial much higher.
How do people affect load?
Each person generates 100W sensible + 40W latent heat; occupancy density is major load driver.
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