Natural ventilation potential for residential buildings in a densely built-up and highly polluted environment. A case study

Abstract

The application of Natural Ventilation (NV) as a measure to improve comfort conditions in transition and summer periods has been a topic of research on the spotlight for years. However, there is a lack of knowledge about how the combined effect of a dense urban layout with high pollutant concentrations may affect its potential. This paper addresses this gap by running detailed thermal simulations for a typical apartment flat located in the Yuzhong district of Chongqing city (China) using a holistic approach that makes use of: i) wind pressure coefficients on building facades from urban-scale CFD simulations, ii) hourly measured values of PM2.5 concentrations and weather variables and iii) indoor environment measurements for validation purposes. Scenario analysis revealed the average amount of air change rates achievable in a year varies from 8 to 15 ACH according to the windows orientation. These figures drop down to around 2 ACH when taking into account reduced windows opening time when outdoor PM2.5 concentrations are too high. The resulting natural ventilation potential of the case study decreases from 4234 hours when outdoor pollution is neglected to 2707 and 529 hours when considering the exposure thresholds set by the Chinese government and the WHO respectively.

Acoustic Design Criteria in Naturally Ventilated Residential Buildings: New Research Perspectives by Applying the Indoor Soundscape Approach

“…NV uses temperature differences or wind pressure differentials to supply and remove air across ventilation openings to and from indoor spaces [9], without the adoption of mechanical systems to drive air movement (e.g., fans). The successful implementation of NV depends on several factors, such as the implemented ventilation strategy [10], the configuration of ventilation devices [11,12], the building floor plan [13], the characteristics of the neighboring buildings [14], the local climate [4,15], the outdoor air quality [1,16,17], and the external acoustic environment [18]. In addition, as a consequence of building users´needs and lifestyle changes (e.g., people spending more and more time out of home) the successful management and control of passive design solutions such as NV could depend on their effective integration into home automation systems, eventually controlled by sensor-driven building management systems.…”

Horizontal Heat Impacts of a Building on Various Soil Layer Depths in Beijing City

“…Due to rapid urbanization in China, more and more buildings are constructed in cities, causing a densely built-up environment in urban areas. Consequently, solar radiation capture is increased and natural ventilation is decreased by these dense buildings [3,4]. Then a series of urban issues have emerged, such as urban heat island effects, air pollution, and increased energy consumption [4,5], all of these issues are to be solved.…”

“…Consequently, solar radiation capture is increased and natural ventilation is decreased by these dense buildings [3,4]. Then a series of urban issues have emerged, such as urban heat island effects, air pollution, and increased energy consumption [4,5], all of these issues are to be solved. Urban heat island effects have been a research hotspot for decades [6] and have been determined by scholars to be the results of artificial surfaces and anthropogenic heat due to urbanization.…”

Survey on the Indoor Thermal Environment and Passive Design of Rural Residential Houses in the HSCW Zone of China

“…Zhou et al [16] studied the influence of a building's air tightness level on the annual dynamic energy consumption of buildings and found that reducing the ACH from 1 to 0.1 could reduce the annual electricity consumption by 15%. Costanzo et al [17] found a tremendous reduction in the natural ventilation potential-expressed in terms of window opening hours-with outdoor pollution threshold values. Chow et al [18] simulated a building in the HSCW zone and introduced a series of measures such as double-glazed windows and reducing the heat transfer coefficients of the exterior walls and roof; they found that these measures reduced the total primary energy by 40%.…”