Comparison of indoor air distribution and thermal environment for different combinations of radiant heating systems with mechanical ventilation systems

2017 ◽  
Vol 39 (1) ◽  
pp. 81-97 ◽  
Author(s):  
Xiaozhou Wu ◽  
Lei Fang ◽  
Bjarne W Olesen ◽  
Jianing Zhao ◽  
Fenghao Wang
Keyword(s):  
Mechanical Ventilation ◽  
Indoor Air ◽  
Thermal Environment ◽  
Air Distribution ◽  
Radiant Heating ◽  
Heating Systems ◽  
Ventilation Systems

scholarly journals Development of Advanced Smart Ventilation Controls for Residential Applications

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5257
Author(s):  
Iain Walker ◽  
Brennan Less ◽  
David Lorenzetti ◽  
Michael D. Sohn
Keyword(s):  
Mechanical Ventilation ◽  
Energy Consumption ◽  
Indoor Air ◽  
Control Strategy ◽  
Energy Use ◽  
Control Strategies ◽  
Related Energy ◽  
Smart Control ◽  
Ventilation Rates ◽  
Ventilation Systems

This study examined the use of zoned ventilation systems using a coupled CONTAM/EnergyPlus model for new California dwellings. Several smart control strategies were developed with a target of halving ventilation-related energy use, largely through reducing dwelling ventilation rates based on zone occupancy. The controls were evaluated based on the annual energy consumption relative to continuously operating non-zoned, code-compliant mechanical ventilation systems. The systems were also evaluated from an indoor air quality perspective using the equivalency approach, where the annual personal concentration of a contaminant for a control strategy is compared to the personal concentration that would have occurred using a continuously operating, non-zoned system. Individual occupant personal concentrations were calculated for the following contaminants of concern: moisture, CO2, particles, and a generic contaminant. Zonal controls that saved energy by reducing outside airflow achieved typical reductions in ventilation-related energy of 10% to 30%, compared to the 7% savings from the unzoned control. However, this was at the expense of increased personal concentrations for some contaminants in most cases. In addition, care is required in the design and evaluation of zonal controls, because control strategies may reduce exposure to some contaminants, while increasing exposure to others.

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 The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Aldona Skotnicka-Siepsiak
Keyword(s):  
Mechanical Ventilation ◽  
Energy Efficiency ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Coanda Effect ◽  
Air Jet ◽  
Coandǎ Effect ◽  
Ventilation Systems

Energy-saving ventilation systems are designed to improve the energy efficiency of buildings. Low energy efficiency in buildings poses a considerable problem that needs to be addressed. Mechanical ventilation with heat recovery has gained increased popularity in recent years. Mechanical ventilation has numerous advantages, including easy adjustment and control, high indoor air quality and elimination of indoor pollutants. Mixing ventilation is the most popular type of mechanical ventilation, in particular in residential buildings. Unsteady ventilation is a type of mixing ventilation that involves stronger mixing effects and smaller vertical temperature gradients to improve indoor air quality (IAQ) and minimize energy consumption. This study examines the possibility of controlling and modifying Coanda effect hysteresis (CEH) to generate unsteady flow and simulate the conditions of unsteady mixing ventilation. The experiment was performed on a self-designed test bench at the University of Warmia and Mazury in Olsztyn. It demonstrated that an auxiliary nozzle can be applied at the diffuser outlet to control CEH and the angles at which the air jet becomes attached to and separated from the flat plate positioned directly behind the nozzle. The study proposes an innovative mixing ventilation system that relies on CEH. The potential of the discussed concept has not been recognized or deployed in practice to date. This is the first study to confirm that an auxiliary nozzle by the diffuser outlet can be operated in both injection and suction mode to control CEH. In the future, the results can be used to design a new type of nozzles for unsteady ventilation systems that are based on CEH control.

A sustainable localised air distribution system for enhancing thermal environment and indoor air quality of poultry house for semiarid region

2021 ◽  
Vol 203 ◽  
pp. 70-92
Author(s):  
Douaa K. Al Assaad ◽  
Mohamad S. Orabi ◽  
Nesreen K. Ghaddar ◽  
Kamel F. Ghali ◽  
Darine A. Salam ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Distribution System ◽  
Thermal Environment ◽  
Air Distribution ◽  
Semiarid Region ◽  
Poultry House

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 Identifying mechanical ventilation issues in classrooms

2018 ◽  
Vol 44 ◽  
pp. 00055
Author(s):  
Julia Janiga ◽  
Joanna Krzempka ◽  
Aleksandra Szczerbińska
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Operating Time ◽  
Mechanically Ventilated ◽  
Ventilation Systems

This article focuses on the issues of indoor air quality in mechanically ventilated classrooms. The aim of the study was to determine the reasons for inadequate air quality reported by occupants. Two different ventilation systems were assessed by measuring CO2 and VOC concentrations in classrooms during operating time. Results showed that in both cases, CO2 levels in the air, even though mostly acceptable, were exceeded throughout the measuring periods on occasion. Based on obtained data, in both cases probable causes for reported ventilation system malfunctions were proposed.

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