Greenhouse Natural Ventilation Vent Area

Sizes buoyancy ventilation from roof and side vent areas, the gutter-to-ridge stack, and the design temperature difference. Two openings in series give about 71% of one of them, not their sum, and airflow falls as the square root of the temperature difference. Above about 2 mph the wind takes over and this becomes a floor.

Q = Cd x A_eff x sqrt(2 g dH dT / T_absolute), with A_eff = 1/sqrt(1/A_roof^2 + 1/A_side^2) for two openings in series.

Buoyancy ventilation, with roof and side vents at 15 to 20% of floor area each the customary schedule and one air change per minute the summer target. The greenhouse manufacturer's vent schedule governs.

Public relations; the vent schedule comes from the house manufacturer.

Estimate. AHJ and licensed professional govern.

Field names used by the API: house_width_ft, house_length_ft, gutter_height_ft, ridge_height_ft, roof_vent_pct, side_vent_pct, design_temp_difference_f, discharge_coefficient, mild_temp_difference_f, floor_area_sqft, roof_vent_area_sqft, effective_area_sqft, series_share_pct, house_volume_ft3, airflow_cfm, air_changes_per_minute, mild_airflow_cfm, mild_share_pct

• Wind not modelled; the stack result is what the house is guaranteed on a still dayspec-v1750 scope
• Discharge coefficient entered; it depends on the vent geometry and insect screenmanufacturer data