The Experts below are selected from a list of 76416 Experts worldwide ranked by ideXlab platform
Honglu Yang - One of the best experts on this subject based on the ideXlab platform.
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performance analysis of a new design of office diffuse ceiling Ventilation System
Energy and Buildings, 2013Co-Authors: Jianhua Fan, Christian Anker Hviid, Honglu YangAbstract:Abstract This paper aims to document and analyse performance of a new design of diffuse ceiling Ventilation System in a typical office room. A full scale measurement is carried out in a climate chamber with an office setup at the Technical University of Denmark. Indoor air temperatures, air speeds, wall surface temperatures, pressure loss of the ceiling and Ventilation effectiveness are measured for an air change rate of 3.5 h−1 and 5.1 h−1 respectively. A computational fluid dynamics model of the office with the diffuse ceiling Ventilation System is built and validated by the full scale measurement. The measurements of pressure loss across the ceiling show a low pressure drop between the plenum and the occupied zone. Ventilation effectiveness is measured to be close to 1 on average under the tested conditions. It is shown that the diffuse ceiling Ventilation System is able to remove indoor pollutant in an efficient way. The draught risk is found to be insignificant by both experimental and theoretical investigations. A design chart based on “flow element” method is created for the diffuse ceiling Ventilation System by calculations with the validated CFD model. The design chart serves as a guideline for design and dimension of the investigated diffuse ceiling terminals as an air distribution System.
Ali Khaleel Kareem - One of the best experts on this subject based on the ideXlab platform.
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Energy saving and indoor thermal comfort evaluation using a novel local exhaust Ventilation System for office rooms.
Applied Thermal Engineering, 2017Co-Authors: Ahmed Qasim Ahmed, Shian Gao, Ali Khaleel KareemAbstract:Energy saving, indoor thermal comfort and inhaled air quality in an office are strongly affected by the flow interaction in the micro-environment around the occupants. The local exhaust Ventilation System, which aims to control the transmission of contaminant and extract contaminant air locally, is widely used in industrial applications. In this study, the concept of the local exhaust Ventilation System is developed for use in office applications. Consequently, a novel local exhaust Ventilation System for offices was combined with an office work station in one unit. Energy saving, thermal comfort and inhaled air quality were used to evaluate the performance of the new System. Experimental data from published work are used to validate the computational fluid dynamic model of this study. The performance of the new System for three different amounts of recirculated air (35%, 50%, and 65% of the total mass flow rate) was investigated numerically in an office room with and without using the new System to show its impact on energy saving, thermal comfort and inhaled air quality. The result shows that the new local exhaust Ventilation System can reduce the energy consumption by up to 30%, compared with an office not using this System. Furthermore, this System was able to reduce the contaminant concentration in a micro-environment area by up to 61% and improve the human thermal comfort in the occupied zone. It can be concluded that using the local exhaust Ventilation concept can make significant improvements to the quality of inhaled air and produce extra energy saving with an acceptable thermal comfort.
Stefano Schiavon - One of the best experts on this subject based on the ideXlab platform.
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energy analysis of the personalized Ventilation System in hot and humid climates
Energy and Buildings, 2010Co-Authors: Stefano Schiavon, Arsen Krikor Melikov, Chandra SekharAbstract:Abstract Personalized Ventilation (PV) is an individually controlled air distribution System aimed at improving the quality of inhaled air and the thermal comfort of each occupant. Numerous studies have shown that PV in comparison with traditional mechanical Ventilation Systems may improve occupants’ health, inhaled air quality, thermal comfort, and self-estimated productivity. Little is known about its energy performance. In this study, the energy consumption of a personalized Ventilation System introduced in an office building located in a hot and humid climate (Singapore) has been investigated by means of simulations with the empirically tested IDA-ICE software. The results reveal that the use of PV may reduce the energy consumption substantially (up to 51%) compared to mixing Ventilation when the following control strategies are applied: (a) reducing the airflow rate due to the higher Ventilation effectiveness of PV; (b) increasing the maximum allowed room air temperature due to PV capacity to control the microclimate; (c) supplying the outdoor air only when the occupant is at the desk. The strategy to control the supply air temperature does not affect the energy consumption in a hot and humid climate.
Luca Baldini - One of the best experts on this subject based on the ideXlab platform.
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Energy analysis of a decentralized Ventilation System compared with centralized Ventilation Systems in European climates: Based on review of analyses
Energy and Buildings, 2016Co-Authors: Moon Keun Kim, Luca BaldiniAbstract:In this study, the decentralized Ventilation (DV) performance of a small air ventilator to replace natural Ventilation for use in urban areas is analyzed and compared to conventional centralized Ventilation (CV) Systems in European climates. Selected European weather conditions were used to determine acceptable conditions for the operation of fan-assisted Ventilation Systems and to analyze the decentralized Ventilation System's cooling and heating loads. Entire fan and pump loads of DV System are numerically calculated based on published data. Compared with a conventional centralized Ventilation System, this System has shorter air transport distances and therefore entails lower pressure losses. In a decentralized System, fan speed and airflow rate are adjusted simply and effectively depending on indoor thermal conditions. A radiant panel with decentralized Ventilation System (RPDV) is shown to have the lowest heating, Ventilation, and air conditioning (HVAC) energy consumption because it not only minimizes supply and exhaust air pressure losses, but can also be operated as a fan-assisted natural Ventilation System during periods when outdoor air can be used without additional thermal loads. Based on numerically calculated and measured data, this study newly adds fan and pump energy analysis of decentralized Ventilation System compared to centralized Ventilation Systems. This study shows the fan and pump energy consumption with analysis of fan-assisted DV System considering outdoor weather condition in European climate.
Qingyan Chen - One of the best experts on this subject based on the ideXlab platform.
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an improved displacement Ventilation System for a machining plant
Atmospheric Environment, 2020Co-Authors: Guanqiong Wei, Bingqian Chen, Dayi Lai, Qingyan ChenAbstract:Abstract Machining plants are often highly polluted indoor environments with dense oil mist generated from metalworking fluids. Workers exposed to oil mist may suffer serious health problems. General Ventilation is often used to dilute the oil mist level below the threshold of health risk. However, it is not easy to organize the flow for ventilating a large machining plant with hundreds of machines in order to effectively remove the oil mist. In order to develop an effective Ventilation System, this study validated a computational fluid dynamics (CFD) program with the RNG k-e model at a high Grashof number by using the measured air temperature and contaminant concentration in several locations in a high-ceiling lab with heat and pollutant sources. Next, the validated CFD program was used to develop an improved displacement Ventilation System in which air is supplied from the lower parts of the support columns in the plant. With thermal plumes generated by machines and workers, the System formed unidirectional airflow that carried pollutants away from the work area of the factory. The System reduced the oil-mist concentration by more than 70% compared with existing Ventilation System. In addition, suspended radiant heaters are recommended for supplemental heating in winter.
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an innovative personalized displacement Ventilation System for airliner cabins
Building and Environment, 2018Co-Authors: Ruoyu You, Daniel Wei, Chao-hsin Lin, Junjie Liu, Qingyan Chen, Yongzhi Zhang, Xingwang ZhaoAbstract:In airliner cabins, mixing Ventilation Systems with gaspers are not efficient in controlling contaminant transport. To improve the cabin environment, this investigation proposed an innovative Ventilation System that would reduce contaminant transport and maintain thermal comfort. We manufactured and installed the proposed Ventilation System in an occupied seven-row, single-aisle aircraft cabin mockup. Air velocity, air temperature, and contaminant distribution in the cabin mockup were obtained by experimental measurements. The investigation used the experimental data to validate the results of CFD simulation. The validated CFD program was then used to study the impact of the locations and number of exhausts on contaminant removal and thermal comfort in a one-row section of a fully occupied Boeing-737 cabin. Although the diffusers in the proposed System were close to the passengers' legs, the air velocity magnitude was acceptable in the lower part of the cabin and the leg area. The proposed System provided an acceptable thermal environment in the cabin, although passengers could feel cold when placing their legs directly in front of the diffusers. The four-exhaust configuration of the new Ventilation System was the best, and it decreased the average exposure in the cabin by 57% and 53%, respectively, when compared with the mixing and displacement Ventilation Systems.
