Performance evaluation of different air distribution systems for removal of concentrated emission contaminants by using vortex flow ventilation system

2018 ◽  
Vol 142 ◽  
pp. 211-220 ◽  
Author(s):  
Zhixiang Cao ◽  
Yi Wang ◽  
Chao Zhai ◽  
Meng Wang
2015 ◽  
Vol 77 (30) ◽  
Author(s):  
Noor Emilia Ahmad Shafie ◽  
Haslinda Mohamed Kamar ◽  
Nazri Kamsah

Air distribution systems inside a bus compartment are important for providing healthy and comfortable environment for passengers. Lack of ventilation inside the bus passenger compartment causes an increase level of air contaminants concentration. Particulate matters and carbon monoxide are indoor air contaminants which can affect the passenger’s health such as respiratory problem and lung cancer. This article reports the results of a CFD simulation on transport of carbon monoxide and particulate matter 1 inside a passenger compartment of a university’s shuttle bus. Fluent CFD software was used to develop a simplified three-dimensional model of the bus passenger compartment. Flow analysis was carried out using RNG k-e turbulent model for air flow, discrete phase and species transport for the air contaminants. Four variations of ventilation system namely two mixing ventilation types, combined mixing with displacement ventilation and combined mixing ventilation with underfloor air distribution was examined. The CFD simulation results show that the use of the combined mixing and displacement ventilation and also the combined mixing and underfloor ventilation types are capable of reducing the concentration of carbon monoxide and particulate matter 1 inside the bus passenger compartment by 81% and 54%, respectively.


2005 ◽  
Vol 4 (2) ◽  
Author(s):  
M. L. Pereira ◽  
A. Tribess

The problem of airborne contamination in surgical infections still raises discussion. The success of the aseptic methods and the use of medicines for the combat of infections are making most surgeons contempt the danger of the aerial particles course. A detailed knowledge of the characteristics of the contamination sources and of the ventilation system performance used at surgery rooms is necessary to guarantee that the ventilation system supplies the pollutant control in ventilation rates that assure the health and the comfort of the occupants. There are many configurations of air distribution systems and a wide range of potential conditions inside a surgery room that are influenced by their performance. In the same way, it is evident the lack of information in the literature regarding which characteristics of the systems of air treatment have stronger influence on the amount of particles in suspension. This paper provides a review of the distribution patterns and air movement at surgery rooms, describing the importance of airborne particles in the infection process, making a comparative analysis of the efficiency of microbiological control of the main airflow systems, identifying and demonstrating the control strategies that can reduce the risks of airborne contamination in surgical infections.


Author(s):  
Stillman Jordan ◽  
Randall D. Manteufel

An optimal air distribution design accomplishes both comfort and ventilation requirements while consuming as little energy as possible. This paper analyzes four different air distribution systems and technologies including single duct variable air volume air handlers, chilled beam cooling systems, total energy recovery wheels, displacement ventilation, and dedicated outside air systems; in an effort to determine the best air distribution system for a representative section of a school in hot and humid climate. The effectiveness of the air distribution systems is evaluated by analyzing how the different technologies take advantage of the natural convective properties of air to create a comfortable environment for the occupied region of the space. Distribution effectiveness and energy consumption must be weighed against considerations such as system complexity and ease of operation. This paper compares several alternative air distribution systems to a baseline single inlet VAV system that is commonly used in new schools designed today. Calculations show that the total energy recovery wheels result in a 16% energy savings over the baseline air distribution system because of the large amount of outside air required in school buildings. Chilled beams are not well suited for schools because of the large amount of outside air required by the space and the sophisticated design and operation needed to prevent condensation from occurring at the chilled beam. The results show that the air distribution system that consumes the least amount of energy is a displacement ventilation system. The system also inherently promotes better indoor air quality as it allows air to naturally rise out and return out of the space with minimal mixing of contaminates that may be recirculated within the room for others to breath. The displacement ventilation system’s overall energy savings of 20% over the baseline is mainly attributed to its total energy recovery wheel and the system’s ability to drastically reduce the cooling load seen by the air cooled chiller by effectively ventilating spaces using less outside air.


2005 ◽  
Vol 4 (2) ◽  
pp. 113 ◽  
Author(s):  
M. L. Pereira ◽  
A. Tribess

The problem of airborne contamination in surgical infections still raises discussion. The success of the aseptic methods and the use of medicines for the combat of infections are making most surgeons contempt the danger of the aerial particles course. A detailed knowledge of the characteristics of the contamination sources and of the ventilation system performance used at surgery rooms is necessary to guarantee that the ventilation system supplies the pollutant control in ventilation rates that assure the health and the comfort of the occupants. There are many configurations of air distribution systems and a wide range of potential conditions inside a surgery room that are influenced by their performance. In the same way, it is evident the lack of information in the literature regarding which characteristics of the systems of air treatment have stronger influence on the amount of particles in suspension. This paper provides a review of the distribution patterns and air movement at surgery rooms, describing the importance of airborne particles in the infection process, making a comparative analysis of the efficiency of microbiological control of the main airflow systems, identifying and demonstrating the control strategies that can reduce the risks of airborne contamination in surgical infections.


2020 ◽  
Vol 11 (3) ◽  
pp. 54-63
Author(s):  
M. P Kalashnikov

When storing fruits and vegetables, vital processes (respiration, heat and carbon dioxide) are actively proceeding. These processes lead to loss of production, significantly affect the temperature, humidity and gas composition of the air in the storage. The optimal storage conditions for fruits and vegetables are rather low positive temperatures and rather high humidity with a sufficient oxygen content in the air. Achieving this difficult task is most effectively accomplished by using active ventilation systems in the storage. The article provides a comparative assessment of setting up air exchange by energy-efficient microclimate systems in potato storages. The results of field studies of air conditions during operation of active air distribution systems in a potato storage are presented. Studies have shown that intensive flow ventilation of products close to the supply duct leads to an increase in losses (shrinkage) of vegetables up to 15 %. Since a number of containers with products are adjacent to large supply air holes thus subjected to the most severe blowing, the quality of potatoes is bound to deteriorate. The use in the active ventilation system of a highly efficient regenerative rotary heat exchanger ( E ≥ 85-90 %) and electronically-switched EC fans allows saving heat and electric energy, as well as reducing the mass loss of products by 21-26 % with directional supply of treated air to the inter-container space and containers with products.


2017 ◽  
Vol 70 ◽  
pp. 359-366 ◽  
Author(s):  
Yongzhi Zhang ◽  
Junjie Liu ◽  
Jingjing Pei ◽  
Jiayu Li ◽  
Congcong Wang

2019 ◽  
Vol 27 (01) ◽  
pp. 1950007 ◽  
Author(s):  
Yong-Il Kwon

The Republic of Korea held the Winter Olympics in February 2018 and built several indoor ice rinks. Recently, the population of viewing and enjoying winter sports in indoor ice rink arenas is increasing and it is expected that the demand for building new indoor ice rink arenas will increase in the future. These indoor ice rinks generally should have an adequate dehumidification and heating system to provide optimal indoor air condition for users (spectators and athletes) under the required heat and humidity conditions. In addition, HVAC system designers should take steps to prevent fogging from condensation on the ice surface and to prevent condensation on the walls. This study was carried out to evaluate the formation of fog near the ice surface by using two air distribution systems applicable to the indoor ice rink arena. It was confirmed that the mixed ventilation method did not cause fog near ice surface, and that there is a great difference in the composition of the indoor thermal environment of the ice rink arena according to the type of ventilation system.


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1354 ◽  
Author(s):  
Arman Ameen ◽  
Mathias Cehlin ◽  
Ulf Larsson ◽  
Taghi Karimipanah

The performance of a newly designed corner impinging jet air distribution method with an equilateral triangle cross section was evaluated experimentally and compared to that of two more traditional methods (mixing and displacement ventilation). At nine evenly chosen positions with four standard vertical points, air velocity, turbulence intensity, temperature, and tracer gas decay measurements were conducted for all systems. The results show that the new method behaves as a displacement ventilation system, with high air change effectiveness and stratified flow pattern and temperature field. Both local air change effectiveness and air exchange effectiveness of the corner impinging jet showed high quality and promising results, which is a good indicator of ventilation effectiveness. The results also indicate that there is a possibility to slightly lower the airflow rates for the new air distribution system, while still meeting the requirements for thermal comfort and indoor air quality, thereby reducing fan energy usage. The draught rate was also lower for corner impinging jet compared to the other tested air distribution methods. The findings of this research show that the corner impinging jet method can be used for office ventilation.


2019 ◽  
Vol 111 ◽  
pp. 02006 ◽  
Author(s):  
Samira Rahnama ◽  
Peter Vilhelm Nielsen ◽  
Alireza Afshari ◽  
Niels Christian Bergsøe ◽  
Hicham Johra ◽  
...  

Diffuse ceiling ventilation system is an air distribution system in which part of the suspended ceiling made of perforated panels is used as an air diffuser for the supply of fresh air. This method has been proven to have a higher cooling capacity compared to conventional air distribution systems. The cooling capacity of the system, however, depends on several parameters. This paper presents evaluation results regarding the cooling capacity of the diffuse ceiling ventilation system in connection to two essential parameters, i.e. the distribution of heat sources in the room and the ratio of perforated to non-perforated panels in the ceiling. The evaluation is based on full-scale experiments performed in a laboratory controlled environment and using a design chart which expresses the limits on the supply airflow rate and temperature. The experimental results indicate that the highest cooling capacity is achieved when the heat sources are distributed evenly and the perforated panels cover the entire ceiling. In the case of partial coverage, the cooling capacity is reduced when the heat sources are placed below the perforated panels. The system can have a higher cooling capacity in the partial coverage configuration compared to the full coverage one depending on the supply airflow rate.


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