Abstract
Built urban environments modify the air quality of the natural ventilation processes in buildings. The experimental assessment of outdoor air change (OACH) processes is complex due to the air volumes involved. The quality of the OACH can be analysed through the ventilation efficiency concept, which has been extensively studied in order to characterize the ventilation of indoor spaces. Ventilation efficiency through the age-of-the-air concept assesses the air-change capacity of a certain space. A procedure formulation for obtaining an adequate control domain (CD) to evaluate outdoor air change efficiency (OACE) is proposed. A methodology in two phases is presented: first, an evaluation stage, in which the outdoor air behaviour patterns are studied; then, a second phase where an ideal control domain (ICD) is obtained in order to comparatively assess several cases in similar urban environments. The outcomes determine a proposed ICD for evaluating the design of efficiently ventilated buildings in open urban built environments. The methodology of validation proposed simplifies the assessment of the building shape and its impact on the quality of the OACH by the OACE. The suggested ICD has dimensions of L = 5H; D = 3H; and T = 2H. ICD enables the representation of the air behaviour and fulfils the imposed requirements to evaluate efficiency with a mean accuracy lower than 0.6%.
Highlights
Natural ventilation in buildings responds to a hybrid process of wind and indoor convective pressures
ideal control domain (ICD) was determined by the combined analysis of two factors: the behaviour of the air and The is assumed thatbyanthe must effectively thethe air behaviour behaviourof and resulting ICDItwas determined combined analysis ofrepresent two factors: theall of the aero-dynamical parameters that intervene in must the outdoor air change (OACH)
Effectively represent selection the air behaviour and misevaluate the affection of the aero-dynamical parameters, resulting in a poor and vague analysis all of the aero-dynamical parameters that intervene in the OACH
Summary
Natural ventilation in buildings responds to a hybrid process of wind and indoor convective pressures. Wind promotes a controlled pressure distribution over the building envelope [1]. Convective phenomena is generated by static pressure due to air density and temperature gradient [2]. In this process, indoor air is mixed with outdoor air supplied through the envelope due to various phenomena (openings, infiltrations, ducts, etc.) [3]. It is required that the resulting mixing has enough quality for human use. Parameters such as humidity, temperature, and mixed or dispersed harmful agents [4] determine the air quality
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
