scholarly journals FEATURES OF VENTILATION SYSTEMS IN AUDITORIUM

2021 ◽  
Vol 9 (1) ◽  
pp. 11-15
Author(s):  
Dar'ya Abramkina ◽  
Gleb Petrov
Keyword(s):  
Indoor Air ◽  
Air Distribution ◽  
Thermal Mode ◽  
Air Velocity ◽  
Air Jets ◽  
Harmful Emissions ◽  
High Concentrations ◽  
Standard Calculation ◽  
Occupied Zone ◽  
Ventilation Systems

The choice of air distribution scheme is the most important task which determines indoor air quality, comfort thermal mode of the room and effectiveness of ventilation systems. The article presents comparative analysis of displacement and mixing ventilation systems for large premises. The methodology of the study is based on existing theoretical provisions and standard calculation approach of supply air jets. Multivariate calculations of mixing air distribution in cinema hall are presented. Horizontal jets along room surfaces can not provide required air velocity. In the case of vertical air distribution relative jet area beyond the recommended values. This factor had thus determined the possible formation of circulation contours with high concentrations of harmful emissions. The results of the calculation shows that the speed of the fan jet at the entrance of occupied zone lower than maximum permissible air mobility. The required temperature is achieved by using all air-distributing units considered.

scholarly journals INVESTIGATING INDOOR AIR QUALITY AND THERMAL COMFORT USING DIFFERENT VENTILATION SYSTEMS UNDER IRAQI CLIMATE

2018 ◽  
Vol 18 (3) ◽  
pp. 422-435
Author(s):  
Ala'a A Mahdi ◽  
Sara Abbas
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Environment ◽  
Simulation Models ◽  
Air Distribution ◽  
Airflow Rate ◽  
Computational Fluid Dynamics Cfd ◽  
Occupied Zone ◽  
Ventilation Systems

Computational Fluid Dynamics (CFD) of indoor environment as well as qualityconsiderations are important element in the study of energy consumption, thermal comfortand indoor air quality in buildings. This paper investigate a comparison work betweenimpinging jet, displacement, and mixing ventilation systems for an isothermal and nonisothermalventilated room for Indoor Air Quality (IAQ) and thermal human comfort underIraqi climate. For IJV system, draught discomfort is the issue of most concern since itsupplies cooled air directly to the occupied zone. This study investigated a number of factorsinfluencing draught discomfort and temperature stratification in an office environment. Theconsidered factors, supply airflow rate and supply air temperature. RNG K-? turbulencemodel was used with the turbulent flow. The second aspect included numerical analyses byadopting ANSYS FLUENT15 code to generate simulation models. A square shaped airsupply device was used with [0.1 times room height (h)] outlet terminal height from the footlevel end. The IJV system proved more efficient than displacement and mixing ventilationsystems. The Air Distribution Performance Index (ADPI) obtained for an isothermal andnon-isothermal ventilated room adopting IJV system gave best values (0.80, 0.83)respectively compared with the other two ventilation systems.

scholarly journals Use of Air Infiltration in Swine Housing Ventilation System Design

2019 ◽  
Vol 35 (3) ◽  
pp. 325-338
Author(s):  
H T Jadhav ◽  
S J Hoff
Keyword(s):  
Ventilation System ◽  
Three Dimensional ◽  
Design Procedure ◽  
Field Testing ◽  
Air Distribution ◽  
Air Jets ◽  
Air Infiltration ◽  
Air Jet ◽  
Archimedes Number ◽  
Ventilation Systems

Abstract.The objective of this research was to develop and analyze the procedure for using recent air infiltration (AI) data collected from commercial swine finishing rooms (SFRs) in the design of negative pressure mechanical ventilation systems (VSs). Air infiltration is an integral part of any ventilation process. Infiltration reduces the pressure differential across planned inlets and at very low pressure differences, cold air jets may drop directly on the animals causing significant discomfort. In this article, a design procedure is proposed for swine housing ventilation systems with the influence of air infiltration included. The method was used on one SFR for which air infiltration data was collected by in-field testing. The air-jet throw, jet momentum number, a newly developed coverage factor, and Archimedes number were used to assess the influence of infiltration on predicted air-jet and fresh-air distribution and to help guide the design of planned inlets in SFR VSs with known infiltration. The analysis completed quantifies the severity of AI on air-jet and air distribution performance, and suggests that for the analysis room to ventilate properly requires a 50% reduction in AI levels beyond field measured curtain and fan infiltration. The analysis completed suggests a method for systematically planning three-dimensional ceiling inlet placement and operation and provides design guidance for new ceiling inlets suitable for SFR VSs. Keywords: Air distribution, Air-jets, Archimedes number, Infiltration, Jet Momentum Number.

Indoor air distribution in a room with underfloor air distribution and chilled ceiling: Effect of ceiling surface temperature and supply air velocity

2019 ◽  
Vol 29 (2) ◽  
pp. 151-162 ◽  
Author(s):  
Jie Gao ◽  
Haichao Wang ◽  
Xiaozhou Wu ◽  
Fenghao Wang ◽  
Zhen Tian
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Indoor Air ◽  
Residential Buildings ◽  
Air Distribution ◽  
Cooling Load ◽  
Air Velocity ◽  
Underfloor Air Distribution ◽  
Chilled Ceiling ◽  
Cooling Loads

An underfloor air distribution (UFAD) system integrated with a chilled ceiling (CC) cooling system may be a potential advanced heating, ventilation and air conditioning system in modern non-residential buildings with high sensible cooling loads. This article presents an experimental study concerning the effect of ceiling surface temperature and supply air velocity on the indoor air distribution in a room with UFAD as the internal and external sensible cooling loads change. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by vertical air temperature difference (VATD), turbulence intensity (TI) and contaminant removal effectiveness (CRE), respectively. The results showed that the average VATD, TI and CRE levels were 0.5°C–1.0°C, 31%–41% and 0.85–1.06 when both internal and external sensible cooling loads were 41.5 W/m2. These evaluation indices varied clearly when the external sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2, whereas they remained almost the same when the internal sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2. The maximum TI coincided with the minimum CRE under the condition of a constant sensible cooling load. Moreover, an air diffusion performance index clearly reduced with an increase in the heat removal effectiveness. It is recommended that it is important to balance the indoor air quality and energy consumption in a room with UFAD + CC.

Improving of ventilation efficiency at air distribution by the swirled air jets

2021 ◽  
Keyword(s):  
Attenuation Coefficient ◽  
Inclination Angle ◽  
Noise Level ◽  
Resistance Coefficient ◽  
Aerodynamic Noise ◽  
Air Distribution ◽  
Air Velocity ◽  
Air Jets ◽  
Local Resistance Coefficient ◽  
Velocity Attenuation

Abstract The article is devoted to decision of actual task of air distribution efficiency increase due to swirled air jets application. The aim of the paper is investigation of swirled air jets, analytical dependencies obtaining for determination of the air velocity attenuation coefficient, aerodynamic local resistance coefficient and noise level from the twisting plates inclination angle; optimization of the twisting plates inclination angle of the air distributor. It has been established that increase of the angle results in the air velocity attenuation coefficient increase and results in decrease of the noise level and resistance coefficient of air distributor. The optimum angle of the plates is determined considering aerodynamic, noise and energy aspects and equals 36°.

Numerical Simulation of Air Distribution of Lateral Supply and Return Pattern Affected by Indoor Heated Source Distribution Models

2014 ◽  
Vol 490-491 ◽  
pp. 854-857
Author(s):  
Ze Qin Liu ◽  
Ning Wang ◽  
Yun Su
Keyword(s):  
Numerical Simulation ◽  
Indoor Air ◽  
Source Distribution ◽  
Air Distribution ◽  
Distribution Models ◽  
Source Models ◽  
Spatially Homogeneous ◽  
Conditioning Room ◽  
Heated Source ◽  
Occupied Zone

In this paper, the numerical simulation was adopted to explore indoor air distribution affected by three typical heated source distribution models, included spatially homogeneous heated source in the room, the heated source distributed evenly at the bottom and the local heated source at the bottom of the room. The characteristics of air distribution effected by three typical heated source models were studied in the air conditioning room with the pattern of lateral supply and return, the scope of rational arrangement in relatively comfortable environment of indoor personnel occupied zone was obtained. The result indicated that, the air distribution with the setting of the spatially homogeneous heated source pattern and the heated source distributed evenly at the bottom pattern were more satisfying than the setting of the local heated source at the bottom pattern.

scholarly journals Enhancing of energetic and economic efficiency of air distribution by swirled-compact air jets

2021 ◽  
Vol 27 (3) ◽  
pp. 171-175
Author(s):  
Vasyl Zhelykh ◽  
Orest Voznyak ◽  
Yuriy Yurkevych ◽  
Iryna Sukholova ◽  
Oleksandr Dovbush
Keyword(s):  
Indoor Air ◽  
Ventilation System ◽  
Air Distribution ◽  
Energy Audit ◽  
Indoor Climate ◽  
Air Jets ◽  
Air Jet ◽  
Urgent Task ◽  
Exhaust Heat ◽  
System Reconstruction

Abstract The article is devoted to solving the urgent task of increasing the efficiency of air distribution by swirled-compact air jets to ensure the normative parameters of indoor air. The dynamic parameters of the swirled-compact air jet during its leakage in the alternating mode and the formation of a dynamic indoor climate in the room are determined. For improvement of comfortable conditions in the room and design of energy saving circuits of air distribution it is suggested to use swirled-compact air jets, which flow from the inflow and exhaust heat recuperators with heat recovery of the exhaust air. An energy audit of the ventilation system reconstruction with a recuperator using was carried out. The method of taking into account the fact of application of several measures, which cannot be carried out simultaneously, and discount rate dynamics is proposed.

Experimental Measurements Research on Internal Micro-Environment of Individually Ventilated Cage System

2013 ◽  
Vol 401-403 ◽  
pp. 1044-1047
Author(s):  
Dong Xie ◽  
Shun Quan Mo
Keyword(s):  
Laboratory Animal ◽  
Close Correlation ◽  
National Standards ◽  
Air Distribution ◽  
Experimental Measurements ◽  
Internal Environment ◽  
Air Velocity ◽  
Cage System ◽  
Environment Parameters ◽  
Edge Side

This paper firstly presents the operation principle of individually ventilated cages (IVC) system. Measurements on micro-environment of IVC system in laboratory animal room at University of South China are conducted to attain the internal environment parameters (Temperature, humidity, air velocity, air cleanliness and noise). Research results show that internal micro-environment parameters basically meet national standards about the barrier environment, but internal air distribution is uneven. In IVC system, air velocities in the edge side are higher than in the middle side, and the maximum air velocity is about 10% larger than the minimum value. Temperature in internal micro-environment depends on indoor temperatures which IVC system located in, and there has a close correlation between air velocity and temperatures. Internal environment evaluation could provide the first-hand research materials for guiding the breeding and management of laboratory animal.

Kitchen and Toilet of the Residence Exhaust Flow Field Analysis

2011 ◽  
Vol 354-355 ◽  
pp. 726-731
Author(s):  
Yue Ren Wang ◽  
Cong Xue ◽  
Jing Zhang
Keyword(s):  
Indoor Air ◽  
Cfd Simulation ◽  
Simulation Software ◽  
Field Analysis ◽  
Air Distribution ◽  
Volume Changes ◽  
Air Volume ◽  
Secondary Pollution ◽  
Comparison Results ◽  
Flow Field Analysis

Adopting the k-ε standard model, the CFD simulation software to simulate the indoor kitchen and toilet different row of indoor air volume air distribution in natural ventilated circumstance, by comparison results show that different row of indoor air volume changes in the rate of secondary pollution rate, and then to provide the change rule of indoor air quality protection reference basis.

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