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.

scholarly journals Transition from n50 to actual air exchange dependent on climatic conditions

2019 ◽  
Vol 282 ◽  
pp. 02101
Author(s):  
Tomasz Kisilewicz ◽  
Katarzyna Nowak-Dzieszko ◽  
Małgorzata Rojewska-Warchał
Keyword(s):  
Energy Demand ◽  
Natural Ventilation ◽  
Simple Procedure ◽  
Ventilation System ◽  
Climatic Conditions ◽  
Model Calculations ◽  
Change Rate ◽  
The Real ◽  
Air Change Rate ◽  
Air Exchange

The knowledge of the air flow and air exchange in the building is critical both on the design and operation stage of the building. Infiltration of air interferes with the mechanical ventilation and determines the proper functioning of the natural ventilation system, still commonly used in the standard buildings. The building airtightness can be described by n50 parameter, however it does not specify the real air exchange in natural conditions. According to the simple procedure of the standard EN ISO 13789, factor n50 may be easily converted to the monthly averaged air change rate. However, it is difficult to accept the same value of air change rate in any month of a year, as it is often done in the certification procedures. More precise, climate dependent conversion procedures have been elaborated in USA, but they were developed for the specific local building technology and local climate conditions. This paper presents the results of the preliminary measurements conducted in a single family house in Poland, built in a heavy-weight technology. The real air exchange rate was measured in various climatic conditions by means of gas tracing method, with CO2 as the tracer gas, in order to prove a relationship between the enhanced procedure and the external conditions. Acceptable agreement between the results of the measurement and model calculations was obtained. Based on the preliminary results, the authors determined the more realistic influence of the enhanced algorithm on the ventilation energy demand. The use of the simplified model resulted in case of the analyzed object in 15% overestimation of the ventilation thermal losses.

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.

scholarly journals Improvement of the Chimney Effect in Stack Ventilation

2021 ◽  
Vol 11 (19) ◽  
pp. 9185
Author(s):  
Romana Antczak-Jarząbska ◽  
Krzysztof Pawłowski ◽  
Maciej Niedostatkiewicz
Keyword(s):  
Natural Ventilation ◽  
Ventilation System ◽  
Common Denominator ◽  
Air Inlet ◽  
Transparent Barrier ◽  
Scale Experiment ◽  
Stack Ventilation ◽  
Chimney Effect ◽  
Rotary Type ◽  
Made In

The article is focused on the airflow in a ventilation system in a building. The work examines the methods which enhance the chimney effect. In this paper, three cases with different chimneys were analyzed for the full-scale experiment. These cases were characterized by different geometrical and material parameters, leading to differences in the intensity of the ventilation airflow. The common denominator of the cases was the room with the air inlet and outlet to the ventilation system. The differences between the experimental cases concerned the chimney canal itself, and more precisely its part protruding above the roof slope. The first experimental case concerned a ventilation canal made in a traditional way, from solid ceramic brick. The second experimental case concerned the part that led out above the roof slope with a transparent barrier, called a solar chimney. In the third experimental case, a rotary type of chimney cap was installed on the chimney to improve the efficiency of stack ventilation. All these cases were used to determine the performance of natural ventilation—Air Change per Hour (CH). Additionally, the paper presents a technical and economic comparison of the solutions used.

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.

The Minimum Ventilation Intensity Research Using Selected Parameters

2013 ◽  
Vol 353-356 ◽  
pp. 3029-3033
Author(s):  
Richard Nagy ◽  
Danica Košičanová
Keyword(s):  
Ventilation System ◽  
Ventilation Rate ◽  
Cfd Simulations ◽  
Change Rate ◽  
Air Change Rate ◽  
Distribution Scheme ◽  
Air Ventilation ◽  
Ventilation Rates ◽  
The Impact ◽  
Selection Of

The air ventilation rates defined in Standard STN EN 15 251:2007 present air change rate in which the objective benefit of proper selection of ventilation system and air distribution scheme is lost (erased) in relation to IAQ [1,2]. With help of sensory evaluation in research the total minimum ventilation rate was estimated. It was reason how to determine major boundary condition (air quantity = air ventilation rate) for minimizing of responsibility size of air quantity (quantitative component of ventilation) and maximize the impact of the choice of distribution scheme and the distribution element (qualitative component of ventilation) for transfer and distribution of pollutants in research. The total air ventilation rate for next experimental measurements was established as the intersection of three air ventilation rates according to research harmonogram. This air ventilation rate was necessary to supply to occupant to experimental classroom and also as input value to CFD simulations.

Influence of Natural Ventilation on Indoor PM2.5 Concentration in Residential Building

2014 ◽  
Vol 675-677 ◽  
pp. 194-198
Author(s):  
Li Zhao ◽  
Chao Chen ◽  
Guo Qing Cao
Keyword(s):  
Pollution Control ◽  
Natural Ventilation ◽  
Residential Building ◽  
Ventilation Rate ◽  
Outdoor Air ◽  
Change Rate ◽  
Air Change Rate ◽  
Indoor Pm2.5 ◽  
Life Behavior ◽  
Pm2.5 Concentration

According to PM2.5 contamination in residential building, a mathematical model is established about the effect of natural ventilation on PM2.5 pollution control based on calculus method. On the basis of some actual cases, such as indoor smoking and cleaning, indoor PM2.5 concentration is calculated for different air change rate and outdoor air quality. The concept of critical ventilation rate is provided. The conclusion of the paper provides some advice on natural ventilation and indoor life behavior.

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