scholarly journals Comparison of Downdraught and Up Draft Passive Air Conduction Systems (PACS) in a Winery Building

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 259
Author(s):  
Ádám László Katona ◽  
István Ervin Háber ◽  
István Kistelegdi
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
General Applicability ◽  
Change Rate ◽  
Air Change Rate ◽  
Simulation Based ◽  
Ventilation Performance ◽  
Air Conduction

A huge portion of energy consumption in buildings comes from heating, ventilation, and air conditioning. Numerous previous works assessed the potential of natural ventilation compared to mechanical ventilation and proved their justification on the field. Nevertheless, it is a major difficulty to collect enough information from the literature to make decisions between different natural ventilation solutions with a given situation and boundary conditions. The current study tests the passive air conduction system (PACS) variations in the design phase of a medium-sized new winery’s cellar and production hall in Villány, Hungary. A computational fluid dynamics simulation based comparative analysis enabled to determine the differences in updraft (UD) and downdraught (DD) PACS, whereby the latter was found to be more efficient. While the DD PACS performed an air change range of 1.02 h−1 to 5.98 h−1, the UD PACS delivered −0.25 h−1 to 12.82 h−1 air change rate. The ventilation performance of the DD version possessed lower amplitudes, but the distribution was more balanced under different wind incident angles, thus this version was chosen for construction. It could be concluded that the DD PACS provides a more general applicability for natural ventilation in moderate climates and in small to medium scale industry hall domains with one in- and one outlet.

Numerical investigation of wind-driven natural ventilation performance in a multi-storey hospital by coupling indoor and outdoor airflow

2016 ◽  
Vol 25 (8) ◽  
pp. 1226-1247 ◽  
Author(s):  
Ruiqiu Jin ◽  
Jian Hang ◽  
Shanshan Liu ◽  
Jianjian Wei ◽  
Yang Liu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Ventilation ◽  
Tracer Gas ◽  
Indoor Airflow ◽  
Change Rate ◽  
Air Change Rate ◽  
Airflow Field ◽  
Ventilation Performance ◽  
Dynamics Simulations

This study employed two ventilation indexes: local mean age of air and air change rate per hour, to investigate wind-induced natural ventilation of 260 wards of a multi-storey hospital building in suburb of Guangzhou using computational fluid dynamics simulations. Using the surface-grid extrusion technique, high-quality hexahedral grid cells were generated for the coupled outdoor and indoor airflow field. Turbulence was solved by the renormalisation group k-ɛ model validated against experimental data with grid independence studies. Homogeneous tracer gas emission was adopted to predict room age of air. The air change rate of cross ventilation and single-sided ventilation can reach 30–160 h−1 and 0.5–7 h−1, respectively. Due to different locations of room openings on the balconies, natural ventilation of a room can be greatly better than its neighbouring room. The wind-induced cross ventilation highly depends on the distance from the room opening to the stagnation point and on the resulting pressure distribution on the target building surface. Furthermore, it is significantly influenced by the upstream buildings, the bent shape of the target building, and the prevailing wind directions. The coupled computational fluid dynamics methodologies with integrated ventilation indexes are useful for assessing the natural ventilation performance in other complex built environments.

scholarly journals Application of the Chimney Cap as a Method of Improving the Effectiveness of Natural Ventilation in Buildings

2020 ◽  
Vol 27 (3) ◽  
pp. 168-175
Author(s):  
Romana Antczak-Jarząbska ◽  
Maciej Niedostatkiewicz
Keyword(s):  
Natural Ventilation ◽  
Transition Period ◽  
Physical Phenomenon ◽  
Ventilation System ◽  
Cost Savings ◽  
Change Rate ◽  
Indoor Pollutants ◽  
Air Change Rate ◽  
Chimney Effect

AbstractAdequately designed natural ventilation is the cheapest and easiest way to effectively remove indoor pollutants and keep the air inside a building fresh. A prediction of the performance and effectiveness of ventilation in order to determine the design of a ventilation system can provide real and long-term cost savings. The worst time in terms of the efficiency of natural ventilation is the spring-autumn transition period [7]. In order to improve the efficiency of natural ventilation, chimney caps are used, among others. They are designed to improve the chimney effect described in colloquial language as a chimney draft. The chimney effect is a physical phenomenon of the formation of a spontaneous flow of a warmer gas, e.g. air, from the bottom up in stem channels [12]. The article analyses the influence of the chimney cowl on the improvement of the chimney effect in an apartment of a multi-family building with natural ventilation. Long-term tests of the chimney draft were carried out for the case without and with a chimney cap. The paper presents the results of the performance (air change rate, ACH) of natural ventilation for a building with an inlet gap measured for the transitional season (between the heating and the summer season). The measurements were performed during a windy period.

Courtyard Space and Natural Ventilation of National Fitness Center in Hot and Humid Areas

2013 ◽  
Vol 361-363 ◽  
pp. 988-994
Author(s):  
Wei Zhang ◽  
Jin Li
Keyword(s):  
Natural Ventilation ◽  
Comfort Level ◽  
Analog Computation ◽  
Fitness Centers ◽  
Change Rate ◽  
Fitness Center ◽  
Air Change Rate ◽  
External Conditions

To improve the air change rate under natural ventilation and the comfort level of sport field of national fitness centers in hot and humid areas, an analog computation was conducted for courtyard models with different sizes and shapes via the softwares such as Fluent and Weather Tool, taking Guangzhou area as an example. It is discovered that under the same external conditions and in a certain building boundary size, enlarging the width of courtyard is beneficial for improving indoor ventilation of sport spaces with the same depth, and semi-open courtyard can lead to better ventilation compared with completely open courtyard with the same width.

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