Displacement Natural Ventilation in an Enclosure With a Convective/Radiative Heat Source and Non-Adiabatic Envelope

This paper studies the real case of natural ventilated space with a convective/radiative heat source and non-adiabatic envelope. The real envelope and heat source are introduced into the ‘Emptying Filling Box’ model and then contribute to achieve a new developed one, Thermal and air Flow Natural Ventilation model. TFNV model combines the thermal and fluid mechanical characteristics of displacement natural ventilation. Two vertical zones of different temperature are divided as that in EFB model. But temperature in the lower zone is higher than outdoor. With TFNV model, natural ventilation parameters can be reasonably predicted — interface height, ventilation airflow rate, occupied zone temperature, etc. By comparison of the results of the two models, it is shown that EFB model underestimates the interface height as well as air temperature in the lower zone and overestimates the temperature difference between the upper and lower zone of the space. It is also observed that EFB model may improperly predict the ventilation airflow rate and ventilation load.