Internal Heat Gains: People, Lighting, Equipment

The heat the building makes inside: occupant sensible and latent gain from the activity-level rate, plus lighting and plug load at 3.412 Btu/h per watt, scaled by the use factor actually on. The sensible/latent split sets the coil's job - a packed conference room flips from sensible-heavy to latent-heavy, and that latent is moisture a sensible-only 'more airflow' fix never removes. The per-person rates come from the ASHRAE activity table. One Manual J component, not the stamped load sheet.

q_people_sensible = occupants x sens_per_person; q_people_latent = occupants x lat_per_person; q_lighting = lighting_w x 3.412 x use_factor; q_equipment = equipment_w x 3.412 x use_factor; q_sensible = q_people_sensible + q_lighting + q_equipment; q_latent = q_people_latent; q_total = q_sensible + q_latent.

ASHRAE / ACCA Manual J internal-gain method (occupant sensible and latent from the activity-level table, lighting and equipment at 3.412 Btu/h per watt), by name; the 3.412 is the watt-to-Btu/h conversion.

The internal-gain relations are public ASHRAE / ACCA Manual J equations; the per-person rates come from the ASHRAE activity table.

Estimate. AHJ and licensed professional govern.

Field names used by the API: occupants, sens_per_person, lat_per_person, lighting_w, equipment_w, use_factor, q_sensible, q_latent, q_total

• People occupant sensible and latent = count x the activity-level rate; the latent is moisture a sensible-only fix never removesASHRAE / ACCA Manual J
• Lighting and equipment watts x 3.412 Btu/h per watt x the use factor actually onASHRAE / ACCA Manual J
• Sensible/latent split the split sets the coil's job; dense-occupancy spaces are sized on the latent loadfirst principles