scholarly journals Assessment of Natural Ventilation System for a Typical Residential House in Poland

2016 ◽  
Vol 22 (3) ◽  
pp. 25-44 ◽  
Author(s):  
Romana Antczak-Jarząbska ◽  
Marek Krzaczek
Keyword(s):  
Natural Ventilation ◽  
Flow Direction ◽  
Air Flow ◽  
Ventilation System ◽  
Winter Season ◽  
Residential Building ◽  
Field Measurements ◽  
Significant Deterioration ◽  
Climate Conditions ◽  
Ventilation Performance

Abstract The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

Three Dimensional Simulation of Ventilation Flow Through a Solar Windcatcher

2019 ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. P. Huynh
Keyword(s):  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation System ◽  
Three Dimensional ◽  
Windward Side ◽  
Efficient Design ◽  
Indoor Space ◽  
Wind Speeds ◽  
Air Stream ◽  
Stack Ventilation

Abstract Natural ventilation is the process of supplying and removing air through an indoor space by natural means. There are two types of natural ventilation occurring in buildings: winddriven ventilation and buoyancy driven or stack ventilation. The most efficient design for natural ventilation in buildings should implement both types of natural ventilation. Stack ventilation which is temperature induced is driven by buoyancy making it less dependent on wind and its direction. Heat emitted causes a temperature difference between two adjoining volumes of air, the warmer air will have lower density and be more buoyant thus will rise above the cold air creating an upward air stream. Combining the wind driven and the buoyancy driven ventilation will be investigated in this study through the use of a windcatcher natural ventilation system. Stack driven air rises as it leaves the windcatcher and it is replaced with fresh air from outside as it enters through the positively pressured windward side. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a three dimensional room fitted with a windcatcher based on the winddriven ventilation alone, buoyancy driven ventilation alone, and combined buoyancy and winddriven ventilation. Different wind speeds between 0 up to 2.5 m/s are applied and the total air flow rate through the windcatcher is investigated with and without temperature of 350 K applied at the windcatcher’s outlet wall. As the wind speed increased the efficiency of the solar windcatcher decreased.

Modelling the Acoustical and Airflow Performance of Simple Lined Ventilation Apertures

2005 ◽  
Vol 12 (4) ◽  
pp. 277-292 ◽  
Author(s):  
D J Oldham ◽  
Jian Kang ◽  
M W Brocklesby
Keyword(s):  
Aspect Ratio ◽  
Cross Section ◽  
High Aspect Ratio ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ventilation Performance ◽  
Acoustic Treatment

The pressure differences that can be used to drive a natural ventilation system are very small and thus large apertures are required to allow sufficient air to enter and leave a building to ensure good air quality or thermal comfort. Large apertures are potential acoustic weak points on a façade and may require some form of acoustic treatment such as absorbent linings, in which case the ventilator is similar to a short section of lined duct. In ducts, the performance of absorbent linings increases with the length of lining and the ratio of the length of lined perimeter to the cross sectional area of the duct. Thus, for a duct of a given cross sectional area, a lining is more effective for a duct with a high aspect ratio than for a duct with a square cross section. However, the high aspect ratio cross section will result in greater flow resistance and impede the airflow performance. In this paper numerical methods are employed to investigate the effect of different configurations of a lined aperture on the acoustical and ventilation performance of the aperture in order to establish the optimum configurations.

scholarly journals Influence of Wind on Air Movement in a Free-Stall Barn During the Summer Period / Wpływ wiatru na ruch powietrza w oborze wolnostanowiskowej w okresie letnim

2013 ◽  
Vol 13 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Piotr Herbut ◽  
Sabina Angrecka ◽  
Grzegorz Nawalany
Keyword(s):  
Natural Ventilation ◽  
Air Flow ◽  
Ventilation System ◽  
Air Velocity ◽  
Summer Period ◽  
Air Masses ◽  
Air Movement ◽  
Microclimatic Conditions ◽  
Hot Weather ◽  
Different Levels

Abstract Use of natural ventilation in the barn should lead to optimal microclimatic conditions over the entire space. In the summer, especially during hot weather, higher air velocity cools cows, which helps to avoid heat stress. The paper presents the results of studies on the evolution of air movement in a modernized free-stall barn of the Fermbet type with the natural ventilation system during the summer period. Based on measurements of velocity and direction of air flow (inside and outside the barn) and observations of smoke indicator, the movement of air masses in different parts of the barn was identified. Significant variations of air flow at different levels of the barn were found. These differences deviate from the accepted patterns of natural ventilation, which can be found in the literature. The range of a draught and stagnant air along with the conditions in which they are built was determined. On this basis, recommendations regarding the location of barns on the plots and the improvement of ventilation in summer were made.

scholarly journals Determination of the speed of air outflow from the ventilation shaft of the warm attic of a multi-storey residential building under different initial conditions

2021 ◽  
Vol 18 (5) ◽  
pp. 126-129
Author(s):  
E. A. Anshukova ◽  
Keyword(s):  
Mathematical Modeling ◽  
System Performance ◽  
Natural Ventilation ◽  
Initial Conditions ◽  
Ventilation System ◽  
Residential Building ◽  
Operating Conditions ◽  
Ventilation Shaft

The operating conditions of a warm attic as an element of natural ventilation of a multi-storey residential building have an impact on the efficiency of the entire ventilation system performance, as well as on the condition of the enclosing structures. The study of the distribution of microclimate parameters in its volume makes it possible to more fully assess the ongoing processes. The result of calculating the rate of air outflow from the ventilation shaft of a warm attic by mathematical modeling is provided.

scholarly journals Effects of Lateral Window Position and Wind Direction on Wind-Driven Natural Cross Ventilation of a Building: A Computational Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
M. Z. I. Bangalee ◽  
J. J. Miau ◽  
S. Y. Lin ◽  
M. Ferdows
Keyword(s):  
Wind Direction ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Ventilation Rate ◽  
Experimental Investigations ◽  
Original Design ◽  
Lateral Direction ◽  
Window Position ◽  
Ventilation Performance ◽  
Moderate Range

Energy is saved when an effective natural ventilation system can provide comfort air to the occupants in a building by replacing a mechanical ventilation system. It also minimizes the risk of the environmental pollution and the global warming. A one story, full scale building was considered to carry out a comparative study of three different cases of wind-driven natural (WDN) cross ventilation with the help of computational fluid dynamics (CFD). In each case, the location of window was changed in lateral direction to predict the probable position for optimum ventilation performance and the angle of wind was varied to check the sensitivity of the wind direction on the flow field. After validating the current methodology through two satisfactory comparisons with the experimental investigations, the governing equations subjected to the corresponding boundary conditions were solved using commercial software and then the results were analyzed. A better location for the windows in each case was proposed. The ventilation purpose was served quite well even if the wind angle was changed in a moderate range from the original design. Furthermore, the velocity components, ventilation rate, surface pressure, ventilation time, and so forth in each case were investigated and compared extensively with those in other cases.

scholarly journals Experimental Investigation of the Air Exchange Effectiveness of Push-Pull Ventilation Devices

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5817
Author(s):  
Sven Auerswald ◽  
Carina Hörberg ◽  
Thibault Pflug ◽  
Jens Pfafferott ◽  
Constanze Bongs ◽  
...  
Keyword(s):  
Heat Dissipation ◽  
Residential Buildings ◽  
Air Flow ◽  
Operation Mode ◽  
Ventilation System ◽  
Field Measurements ◽  
Gas Analysis ◽  
Decentralised Systems ◽  
Set Up ◽  
Air Exchange

The increasing installation numbers of ventilation units in residential buildings are driven by legal objectives to improve their energy efficiency. The dimensioning of a ventilation system for nearly zero energy buildings is usually based on the air flow rate desired by the clients or requested by technical regulations. However, this does not necessarily lead to a system actually able to renew the air volume of the living space effectively. In recent years decentralised systems with an alternating operation mode and fairly good energy efficiencies entered the market and following question was raised: “Does this operation mode allow an efficient air renewal?” This question can be answered experimentally by performing a tracer gas analysis. In the presented study, a total of 15 preliminary tests are carried out in a climatic chamber representing a single room equipped with two push-pull devices. The tests include summer, winter and isothermal supply air conditions since this parameter variation is missing till now for push-pull devices. Further investigations are dedicated to the effect of thermal convection due to human heat dissipation on the room air flow. In dependence on these boundary conditions, the determined air exchange efficiency varies, lagging behind the expected range 0.5 < εa < 1 in almost all cases, indicating insufficient air exchange including short-circuiting. Local air exchange values suggest inhomogeneous air renewal depending on the distance to the indoor apertures as well as the temperature gradients between in- and outdoor. The tested measurement set-up is applicable for field measurements.

A numerical investigation on the impacts of voids combinations on natural ventilation of high-rise residential building

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamza Laloui ◽  
Noor Hanita Abdul Majid ◽  
Aliyah Nur Zafirah Sanusi
Keyword(s):  
Thermal Comfort ◽  
Indoor Air ◽  
Design Methodology ◽  
Natural Ventilation ◽  
Residential Building ◽  
Air Velocity ◽  
Content Type ◽  
High Rise ◽  
Living Unit ◽  
Ventilation Performance

Purpose This paper aims to investigate the impacts of introducing voids combinations on natural ventilation performance in high-rise residential building living unit. Design/methodology/approach This study was carried out through field measurement and computational fluid dynamics methods. The parameters of the study are void types and sizes, and a wind angle was used to formulate case studies. Findings The results indicate that the provision of a single-sided horizontal void larger by 50% increase the indoor air velocity performance up to 322.37% to 0.471 m/s in the living unit and achieves the required velocity for thermal comfort. Originality/value Passive design features are the most desirable techniques to enhance natural ventilation performance in the high-rise residential apartments for thermal comfort and indoor air quality purposes.

scholarly journals An Attempt to Design a Naturally Ventilated Tower in Subtropical Climate of the Developing Country; Pakistan

2017 ◽  
Vol 21 (1) ◽  
pp. 47-67 ◽  
Author(s):  
Maha Sohail
Keyword(s):  
Developing Country ◽  
Natural Ventilation ◽  
Winter Season ◽  
Residential Building ◽  
Building Envelope ◽  
Subtropical Climate ◽  
Night Time ◽  
High Rise ◽  
Shading Devices ◽  
Air Conditioning Systems

Abstract A large proportion of the world’s population resides in developing countries where there is a lack of rigorous studies in designing energy efficient buildings. This study is a step in designing a naturally ventilated high rise residential building in a tropical climatic context of the developing country, Pakistan. Karachi, the largest city of Pakistan, lies in the subtropical hot desert region with constant high temperature of average 32 °C throughout the summer and no particular winter season. The Design Builder software package is used to design a 25 storey high rise residential building relying primarily on natural ventilation. A final conceptual design is proposed after optimization of massing, geometry, orientation, and improved building envelope design including extensive shading devices in the form of trees. It has been observed that a reduction of 8 °C in indoor ambient temperature is possible to achieve with passive measures and use of night time ventilation. A fully naturally ventilated building can reduce the energy consumption for cooling and heating by 96 % compared to a building using air conditioning systems.

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