scholarly journals Detailed measured air speed distribution in four commercial buildings with ceiling fans

2021 ◽  
pp. 107979
Author(s):  
Maohui Luo ◽  
Hui Zhang ◽  
Paul Raftery ◽  
Linxuan Zhou ◽  
Thomas Parkinson ◽  
...  
Keyword(s):  
Commercial Buildings ◽  
Speed Distribution ◽  
Air Speed

scholarly journals The effect of air velocity on moisture buffering

2019 ◽  
Vol 282 ◽  
pp. 02007 ◽  
Author(s):  
Valeria Cascione ◽  
Eugenio Cavone ◽  
Daniel Maskell ◽  
Andy Shea ◽  
Pete Walker
Keyword(s):  
Air Quality ◽  
Relative Humidity ◽  
Buffering Capacity ◽  
Climatic Chamber ◽  
Air Velocity ◽  
Speed Distribution ◽  
Velocity Correction ◽  
Air Speed ◽  
The Relationship ◽  
Moisture Buffering

Hygoscopic finishing materials improve the indoor hygrothermal comfort and air quality, as they reduce the extremes of variation in relative humidity. This property, known as moisture buffering, is related to the capacity of hygroscopic materials to adsorb and desorb moisture from the air. Air velocity plays an important role on the sorption performances of materials: increasing the air speed leads to increased moisture buffering capacity. In order to obtain comparable results, several moisture buffering protocols require the air speed to be constant and around 0.1 m/s during tests. However, those tests are usually performed in climatic chambers, where air speed cannot be controlled and the flow may not be homogenous. The aim of this study is to demonstrate, that positioning test specimens in different locations within the same chamber gives different moisture buffering value results, due to the non-homogenous air speed distribution. For this reason, air velocity has been monitored, measuring the differential pressure and air speed in different locations in a climatic chamber. Moisture buffering tests have been performed in six locations of the chamber and a correlation between the two analyses has been evaluated. The significance of this paper is to understand the relationship between air speed and moisture buffering performances, in order to determine an air velocity correction factor, which enables the moisture buffering value to be evaluated when existing protocols cannot be adhered.

scholarly journals SIMULASI PENGGUNAAN DIFFUSER PADA TURBIN ANGIN SUMBU HORISONTAL UNTUK KENAIKAN DAYA

2012 ◽  
Vol 9 (1) ◽  
Author(s):  
Sulistyo Atmadi ◽  
Ahmad Jamaludin Fitroh
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Flow Rate ◽  
Power Output ◽  
Area Ratio ◽  
Diameter Ratio ◽  
Speed Distribution ◽  
Ratio Variation ◽  
Air Speed ◽  
Cfd Method

 One technique to improve the power output of a wind turbine is by implementing a diffuser, which is called the diffuser augmented wind turbine (DAWT). The area ratio between the inlet and outlet of the diffuser increases the flow rate inside the diffuser which in effect produces higher output power. In this research, a 2 meters rotor diameter was used. Diffuser diameter ratio variation of 2, 3, 4, and 5 were chosen which provides inlet diameter of 4, 6, 8, and 10 meter respectively. Power rotor coefficient is assumed to be constant of 0.30. Air speed distribution inside the diffuser is calculated using CFD method. The inlet speed to the diffuser is varied to give 4 different speeds. The wind angle at the inlet is also varied at 0º, 30º and 60º. The simulation result showed that at 0 degree angle, diffuser diameter ratio variation of 2, 3, 4, and 5 will increase the power output about 58, 622, 3169, and 11519 times respectively. It also showed that the increase in the output power for diameter diffuser ratio of 2 at 0º and 60º angle is 58 and 4 times respectively. Keywords:Wind turbine, Diffuser, CFD

Modeling Interstation Travel Speed of Hybrid Bus Rapid Transit within A Bayesian Framework

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Ji-hua Hu ◽  
Jia-xian Liang
Keyword(s):  
Road Traffic ◽  
Travel Speed ◽  
Bayesian Framework ◽  
Bus Rapid Transit ◽  
Rapid Transit ◽  
Important Indicator ◽  
Main Road ◽  
Traffic Lights ◽  
Speed Distribution ◽  
Hybrid Bus

Interstation travel speed is an important indicator of the running state of hybrid Bus Rapid Transit and passenger experience. Due to the influence of road traffic, traffic lights and other factors, the interstation travel speeds are often some kind of multi-peak and it is difficult to use a single distribution to model them. In this paper, a Gaussian mixture model charactizing the interstation travel speed of hybrid BRT under a Bayesian framework is established. The parameters of the model are inferred using the Reversible-Jump Markov Chain Monte Carlo approach (RJMCMC), including the number of model components and the weight, mean and variance of each component. Then the model is applied to Guangzhou BRT, a kind of hybrid BRT. From the results, it can be observed that the model can very effectively describe the heterogeneous speed data among different inter-stations, and provide richer information usually not available from the traditional models, and the model also produces an excellent fit to each multimodal speed distribution curve of the inter-stations. The causes of different speed distribution can be identified through investigating the Internet map of GBRT, they are big road traffic and long traffic lights respectively, which always contribute to a main road crossing. So, the BRT lane should be elevated through the main road to decrease the complexity of the running state.

Sign in / Sign up

Export Citation Format

Share Document