89. Study on Displacement Ventilation System in Commercial Kitchens. Part 2. Comparison Between Conventional HVAC System and Displacement Ventilation by Experiment and CFD Simulation

2006 ◽  
Author(s):  
H. Yoshino ◽  
S. Ogita ◽  
Y. Kondo ◽  
S. Adachi
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.


2010 ◽  
Vol 75 (648) ◽  
pp. 179-187
Author(s):  
Shunsuke OGITA ◽  
Yasushi KONDO ◽  
Hajime YOSHINO ◽  
Koichi NISIKAWA

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 658
Author(s):  
Subin Mattara Chalill ◽  
Snehaunshu Chowdhury ◽  
Ramanujam Karthikeyan

Controlled crop growth parameters, such as average air velocity, air temperature, and relative humidity (RH), inside the greenhouse are necessary prerequisites for commercial greenhouse operation. Frequent overshoots of such parameters are noticed in the Middle East. Traditional heating ventilation and air-conditioning (HVAC) systems in such greenhouses use axial fans and evaporative cooling pads to control the temperature. Such systems fail to respond to the extreme heat load variations during the day. In this study, we present the design and implementation of a single span, commercial greenhouse using box type evaporative coolers (BTEC) as the backbone of the HVAC system. The HVAC system is run by a fully-automated real time feedback-based climate management system (CMS). A full-scale, steady state computational fluid dynamics (CFD) simulation of the greenhouse is carried out assuming peak summer outdoor conditions. A pilot study is conducted to experimentally monitor the environmental parameters in the greenhouse over a 20-h period. The recorded data confirm that the crop growth parameters lie within their required ranges, indicating a successful design and implementation phase of the commercial greenhouse on a pilot scale.


2012 ◽  
Vol 52 ◽  
pp. 119-128 ◽  
Author(s):  
Han-Qing Wang ◽  
Chun-Hua Huang ◽  
Di Liu ◽  
Fu-Yun Zhao ◽  
Hai-Bo Sun ◽  
...  

Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.


Author(s):  
Edgar C. Ambos ◽  
Evan Neil V. Ambos ◽  
Lanndon A. Ocampo

Due to its significant role in improving indoor air quality, displacement ventilation system is widely adopted in current literature. This paper proposes a displacement ventilation system for room conditions with ceilings that are relatively low, internal heat load could be high, walls could be sunlit, and occupants doing the low physical activity. These conditions are prevalent in the Philippines, being a tropical country. Input parameters to the design process such as heat load, the height of the ceiling, comfort, and indoor air quality requirements were generated, and the main output parameters are the stratification height and ventilation airflow rate. To demonstrate the proposed displacement ventilation system, four cases were generated. Results show that the ventilation airflow rates obtained from the four cases were greater than the minimum outdoor air requirements for health in conference rooms and large assembly areas which are 17.5 and 3.5 liters/sec*person respectively, for smoking and no smoking rooms.


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