Indoor Climate Analysis for Urban Mobility Buses: a CFD Model for the Evaluation of thermal Comfort
Issue:
Volume 1, Issue 1, May 2013
Pages:
1-8
Received:
11 April 2013
Published:
2 May 2013
Abstract: The aim of this work is to analyze the indoor climate in city buses; the study was developed by numerical simulation and experimental validation carried out on the urban mobility buses of the city of Rome (Italy). Several factors have contributed to increase the concern about the comfort evaluation in vehicles and particularly in city buses. Due to the rising of the mobility needs, time that people spend in vehicles has grown substantially. The thermal environment in urban buses also varies greatly: passengers are exposed to local heating and/or cooling due to vertical temperature gradients, radiant asymmetry and local unexpected airflow. The interaction of the cabin thermal environment, created by the HVAC-system, the outdoor conditions as well as the occupants is rather complex. At the moment no standards exist for assessment and classification of the thermal environment quality in vehicles. To obtain some evidences, in order to enhance the indoor climate for a city bus and to improve occupants’ comfort monitoring local temperature and air distribution around passengers, we have developed a mathematical model. The numerical model was implemented with Computational Fluid Dynamic software (CFD, Fluent Inc.): it permits the evaluation of the thermal and fluid-dynamic performances of the air conditioning system and diffusers’ distribution. To gain a deeper understanding of the local climate comfort, the numerical simulation results were experimentally validated by several measurements inside the urban buses performed under real operative conditions during the summer season.The experimental results are in good agreement with the CFD evidences. This shows that the model developed can give reliable results to optimize and locally modify the air diffusers distribution inside cabin spaces. These evidences can help to improve the air conditioning distribution as a function of the obstructions’ typical for a city bus vehicle and to reduce the draught risk related to the bus stop door apertures. One of the most important reasons of local temperature differences and unexpected air velocity gradients is due to the multi-door system apertures at each bus stop. This situation is particularly recurrent in a city area where an urban bus can afford several stops during his programmed route. For this reason it’s important to get more information about this transient localized load for the climate conditions and about the time needed to reach again the steady conditions. To avoid or, at least, reduce this kind of problem it is proposed an air knife screened doors system bus. The thermo fluid dynamic results obtained show a significant improvement in the indoor climate comfort.
Abstract: The aim of this work is to analyze the indoor climate in city buses; the study was developed by numerical simulation and experimental validation carried out on the urban mobility buses of the city of Rome (Italy). Several factors have contributed to increase the concern about the comfort evaluation in vehicles and particularly in city buses. Due to...
Show More
Effects of Faujasite X and Y Zeolites on the 1,1,1-Trichloro-2,2’ bis(p-chlorophenyl)ethane (DDT) Degradation during Water Purification
Chrispin Ounga Kowenje,
Elly Tetty Osewe,
Joseph Owuor Lalah
Issue:
Volume 1, Issue 1, May 2013
Pages:
9-15
Received:
31 May 2013
Published:
30 June 2013
Abstract: The ability of zeolites to abstract and denature organochloride pesticides finds application in water purification practices. In this study, activated faujasite X and Y zeolites were separately exposed to 1, 2 and 4 ppm concentrations of 1,1,1-trichloro-2,2’ bis(p-chlorophenyl) ethane (dichloro dipheny trichloroethane - DDT) water solutions. For the 1 ppm DDT solutions, the resultant degradation products and residual DDT were minimal with concentrations in zeolite treatments reducing to below detection limit (0.005 ppm) in about 2 hours. In addition, the rate of dissipation was found to somewhat depend on the levels of DDT concentration and the type of zeolite used. The main degradation product in samples exposed to faujasite X was dichloro dipheny dichloroethylene (DDE) whereas in the faujasite Y exposed samples, both the DDE and dichloro diphenyl dichloroethane (DDD) were obtained.
Abstract: The ability of zeolites to abstract and denature organochloride pesticides finds application in water purification practices. In this study, activated faujasite X and Y zeolites were separately exposed to 1, 2 and 4 ppm concentrations of 1,1,1-trichloro-2,2’ bis(p-chlorophenyl) ethane (dichloro dipheny trichloroethane - DDT) water solutions. For t...
Show More
