The Calculation of Natural Ventilation and Comfort

Natural ventilation can be used to greatly reduce cooling loads and increase human comfort in buildings in hot, humid climates. Airflow rates directly affect a building's heat balance by removing internal gains and directly affect comfort levels by increasing the body'€™s convective and evaporative heat-transfer coefficients; these airflow rates are determined by the wind pressure on the faces of the building (which is calculated from the wind speed and pressure coefficient) and the amount of open area. Wind pressure coefficients can be obtained in three ways: (1) by direct field measurement, (2) by scale-model experiments in a wind-tunnel, and (3) by comparison with standard wind-tunnel data. In this report the authors describe measurements made on two buildings at the Kaneohe Marine Corps Air Station (KMCAS) on the island of Oahu, Hawaii, during the summer of 1982. These full-scale measurements of pressure coefficients will be compared to reduced-scale measurements made at the boundary-layer wind-tunnel at the Naval Civil Engineering Laboratory (NCEL). Estimates of the indoor comfort levels for different window conditions will be used as a basis for determining the acceptability of natural ventilation for cooling.