bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Investigation for the Arrangement of Perforated Tile under a Non-uniform Heat Source Condition in a Raised-floor Data Center
Authors: Huang Jianwen , Chen Cheng , Guo Guiyang , Zhang Zhang , Li Zhen 
Published: August 2019

Abstract
The research object of this paper was a typical raised-floor data center where the heat load of each rack was non-uniform. The non-uniform heat source caused that the temperature field in the room was also non-uniform and part of the rack outlet temperature was relatively high. In view of this problem, a numerical simulation was conducted to investigate the effect of the arrangement of perforated tile on the air distribution and the temperature field. The results indicate that a better arrangement of perforated tile could optimize the air distribution and make the temperature field in the room more uniform. The maximum rack outlet temperature was reduced by about 2.1°C under the proper condition of the tiles opening ratio, which means that the energy efficiency of the cooling system was accordingly improved. The adjustment of the tiles opening ratio could be a solution to the non-uniform heat source problem in a raised-floor data center.
An economic analysis of the solar photovoltaic/thermal (PV/T) technologies in Sweden: a case study
Authors: Zhang Xingxing , Wu Jinshun , Pan Song , Han Mengjie 
Published: August 2019

Abstract
The solar energy share in Sweden will soar over the next decades. Such transition offers not great opportunity but uncertainties for the emerging solar PV/thermal (PV/T) technologies. There are still critical challenges for PV/T development in Swedish scenario. This paper aims to investigate the local policies and market structures in Sweden by a set of analytical economic frameworks and a case study. A macro-economic exposure analysis in Swedish context is conducted and a PEST model is then applied for analysis of external environment of PV/T industry in Sweden. The PV/T market is further analysed based on a case product by means of SWOT and Porter’s five forces. The whole study concludes that the market of solar PV/T is expanding mostly towards small-and medium-sized energy plants. The market position of the case company meets the trend of PV/T market, which has an overwhelming competence against its competitor in the domestic market. This paper is expected to clarify the economic situations of PV/T in Sweden and promote its further development towards sustainable and low-carbon economics.
Experimental study on the thermal performance of ethylene-tetrafluoroethylene (ETFE) foil cushions
Authors: Flor J-F , Sun Y , Beccarelli P , Rowell C , Chilton J , Wu Y 
Published: August 2019

Abstract
ETFE pneumatic foil constructions are used increasingly by designers and builders as an alternative to glass in state of the art building envelopes. Low weight, high transparency, mechanical resistance and self-cleaning properties of ETFE may contribute to the overall performance. However, reliable information on the thermal performance of ETFE cushions in building envelopes is scarce, limiting the performance prediction in energy simulations. The present study aims to investigate the thermal performance of air-inflated ETFE foil cushions and evaluates parameters of material properties and design which might affect the thermal transmittance. The paper reports on the experiments conducted to quantify the thermal performance using a climate chamber and full-size mock-ups. Based on available standards, tests were designed to compare the thermal performance of three different ETFE cushion designs, under changing climate conditions. The design variations, including frit prints and switchable shading mechanisms, were tested and compared at hot, temperate and cold weather scenarios. The test series provided detailed results on the thermal performance of ETFE cushions which may be of use for the comparison with the performance of other building components and materials, serve as input for energy simulations and provide a theoretical basis for future developments of novel building envelopes.
Annealing temperature dependence of properties of CdSe thin films by RF-sputtering
Authors: Wang Ailing , Li Chunxiu , Zhang Jingquan , Wu Lili , Wang Wenwu , Feng Lianghuan 
Published: August 2019

Abstract
Cadmium Selenide (CdSe) is a II-VI group compound semiconducting material with a direct band gap about 1.74 eV, which is widely applied in thin film transistors, light emitting diodes and photoelectrochemical (PEC) cells. In recent years, the application of CdSe thin films to CdTe thin film solar cells has attracted the attention of people. CdSe thin films were synthesized using radio frequency magnetron sputtering method on Corning glass substrates at room temperature. The as-deposited films were annealed at various temperatures (200°C, 300°C, 400°C and 500°C) in N2 atmosphere for 1h and the effect of annealing temperature on structural, morphological, compositional, optical and electrical properties was studied. X-ray diffraction (XRD) indicates that the structure of CdSe thin films transforms from cubic to hexagonal structure when annealing temperature changes from room temperature to 500°C. Scanning electron microscope (SEM) images show that the crystallite size of CdSe thin films has no obvious increase with annealing temperature increasing from 200°C to 400°C, which is all about 33 nm. However, grains with size of 200 nm were precipitated on the surface of CdSe thin film annealed at 500°, and the Se content of CdSe thin film decreased. The band gaps of CdSe thin films were found to firstly decrease, and then gradually increase with the increase of annealing temperature. The minimal band gap of CdSe thin film is 1.63eV when annealed at 300°C. The conductivity of CdSe thin film annealed at 500° increased by two orders of magnitude compared with as-deposited CdSe thin film.
The research of post-treatment on Cd1-xMgxTe thin films and CdTe solar cells
Authors: Feng Ye , Yu Mingzhe , Huang Jian , Hao Xia , Li Wei , Zhang Jingquan , Wu Lili 
Published: August 2019

Abstract
As for it higher band gap, Cd1-xMgxTe (CMT) material has been taken into consideration to improve the open-circuit voltage of CdTe solar cells as an electron reflector layer. An essential step in the development of this new interlayer is the passivation process. X-ray Diffraction (XRD) and scanning electron microscope (SEM) results give us the suitable annealing temperature range of CMT thin films from 350°C to 400°C, and suggest that the annealing process is beneficial to grain growth and recrystallization. The concentration of CdCl2 solution has an influence on the crystallinity of the thin films and coating method would contribute to electrical performance of the devices. The CMT/CdTe cells which underwent the two-step annealing procedure at high purity nitrogen atmosphere showed the significant improvements in device performance. Furthermore, the CdTe solar cells with the CdTe cap layer and Te/Cu back contacts also demonstrated higher performance.
Optical design and experiment evaluation of a novel asymmetric compound parabolic concentrator (ACPC) integration with PV for building south wall application
Authors: Xuan Q , Li G , Pei G , Lu Y , Su Y , Ji J 
Published: August 2019

AbstractCompound parabolic concentrator (CPC) as a typical low-concentration-ratio concentrator is an interesting topic for it can work as the static concentrator without any additional tracking systems or seasonal adjustments, which shows a promising concept of introducing the concentrating PV technology for building application. Therefore, based on the compound parabolic curves, a novel asymmetric compound parabolic concentrator (ACPC) is proposed in this paper for building south wall integration. The optical model of the ACPC is built by the software Lighttools to study its optical performance, and the structure parameters of it are optimized through the optical simulation. Then the prototype of the ACPC integrated with the PV cell as the ACpC-PV module is manufactured and assembled. The indoor experiments by the solar simulator (Oriel Sol3A Model 90943A) from the Newport Corporation at the dark environment with the temperature of 25 °C are conducted to study the electrical performance of the ACPC-PV module. The simulation and experiment results show that the acceptance range of the ACPC with the geometric concentration ratio of 2.4X can be 65° with high optical efficiency. A good agreement is observed between the simulation and experiment results despite the deviation of around 13% which is inevitable due to all kinds of errors, such as manufacturing errors, mismatch losses, series resistance losses, etc.
Airflow Organization in a Transformable Shelter
Authors: Guo Liang , Ye Hong 
Published: August 2019

Abstract
The environmental control system of a shelter can provide comfortable temperature, air velocity and fresh air supply for members indoor, protecting them from the extreme weathers or oxygen-poor environment in the field. A shelter with transformable walls will have a large available space including the core module and extended modules for diverse demands such as dining or sleeping. The airflows in such a limited space can be inevitably influenced by walls and furniture. In the study, a transformable shelter with top supply and bottom return air organization mode was taken as the research object. The air supply duct on the ceiling of the shelter was designed to uniform the supplying air quantity through each outlet by adding baffles in the duct. Baffles can also make the export winds nearly perpendicular to the duct wall. The indoor airflow velocity and temperature fields in the condition of people gathering for dinner were obtained by simulation, so as that in the condition of people scattering for sleeping. In the dining condition, the barriers to the uniform airflow and temperature are the crowd occupying the core module. In the sleeping condition, the dominating barriers are the walls between different modules. The airflows were uniformed between different modules by opening apertures across the partitions. In view of human comfort, a comprehensive evaluation of the air flow organization was given, which presents an essential reference for system design and optimization.
Preliminary analysis of supercritical CO2 Brayton cycle applied to the solar thermal plant
Authors: Sun L , Xie YH , Zhang D 
Published: August 2019

Abstract
The use of a highly compacted and efficient supercritical CO2 (S-CO2) Brayton cycle has become an effective way in utilizing solar energy. This work performs a comprehensive parametric study for S-CO2 Brayton cycle applied to the solar thermal plant. Several different power cycle layouts including basic regenerative cycle, recompression cycle, intercool cycle and reheat cycle are analysed by the computational models consist of various components in this paper. Then, the optimization of parameters including the cycle turbine inlet temperature and so on, is also performed based on genetic algorithm to achieve the best cycle performance. The most promising cycle configuration is selected by comparison of the compromise between cycle and recuperator performance. This study provides some reference for the related research of the S-CO2 Brayton cycle integrated with solar thermal systems.
Analysis of Point Daylight Factor (PDF) Average Daylight Factor (ADF) and Vertical Daylight Factor (VDF) under various unobstructed CIE Standard Skies
Authors: W Li Danny H , Li Shuyang , Chen Wenqiang , Lou Siwei 
Published: August 2019

Abstract
The usual method for computing natural illuminance for a given location in a building is the daylight factor (DF) approach, which is based on the traditional overcast sky without sunlight, as defined by the International Commission on Illumination (CIE). In 2003, the CIE adopted a range of 15 skies as international standard models that represent the actual skies of many places and cover the whole probable spectrum of skies found in nature. Previously, we developed a number of calculation tools to predict daylight illuminance for rooms facing different orientations under various CIE Standard skies. This paper presents the work on the calculation of the point DF (PDF), average DF (ADF) and vertical DF (VDF) under various overcast and non-overcast skies. The strong correlations between these three DF types can help to estimate the required DF values for architectural and daylighting designs and evaluations.
A smart hybrid pole with street lighting and EV charging based on DC micro-grid and renewable energy
Authors: Zhang Yongming , Li Li , Yan Zhe , Yao Jiawei 
Published: August 2019

Abstract
In order to efficiently utilize renewable energy and solve roadside fast charging of Electric Vehicle (EV) problem, a smart hybrid pole system is proposed in this paper, which integrated with renewable energy Street Lighting Pole (SLP) and EV charging. Besides, smart hybrid pole can also serve as the backup power for traffic lights. In this system, several renewable energy SLPs are coupled together by Direct Current (DC) micro-grid with storage battery, so it is suis for both DC fast charging and slow charging for EV. More importantly, the energy efficiency in this system can become much higher than alternating current (AC) EV charging system, because renewable energy power such as photovoltaic (PV), load and energy storage are all DC subsystem. Then for studying the suitable number in a group of smart hybrid pole, the group model of smart hybrid pole is presented. In addition, the hybrid pole energy storage system can be controlled by a cloud management platform, so it is convenient to make the decision to charge or discharge according to the different power prices. The smart hybrid pole solution is conducive to EV charging and the efficient application of renewable.
The relative change of drying rate as a function of the cumulative ventilation air drying potential in a thin-layer solar drying facility
Authors: Krawczyk P 
Published: August 2019

Abstract
Controlling low-temperature drying facilities which utilise non-prepared air is quite difficult, due to very large variability of ventilation air parameters – both in daily and seasonal cycles. The results of experimental studies of sewage sludge solar drying process in thin-layer solar dryer have been presented. It was found that regardless of weather conditions, the rate of sewage sludge drying is significantly changed during drying process. The results showed that the rate of drying decreases with increasing so called cumulative ventilation air drying potential.Knowledge on current dryin rate provides new possibilities for controlling such systems. Based on the results, operating recommendations for analysed type of dryer have been formulated.
Experimental data analysed in the paper was collected in 2012 - 2014 during operation of a test solar drying facility in a sewage treatment plant in Błonie near Warsaw, Poland.
Steady-Flow-Type Particle Receiver for High-Temperature Solar Thermal Storage
Authors: Matsubara Koji , Suzuki Yudai , Sakurai Atsushi , Bellan Selvan , Kodama Tatsuya 
Published: August 2019

Abstract
The concentrated solar power is utilized for industrial thermal usage, electricity generation and fuel production. To increase the solar thermal temperature is essential for enhancing the thermal efficiency of the energy conversion and for widening application. The synthetic oil, widely used for solar thermal storage, pylorizes at 400 °C, and this cannot be used for very high temperatures. The authors used quartz sand as thermal storage medium in the fluidized bed receiver, and achieved the thermal receiver temperatures beyond 1000 °C in the previous report. The research work was further made on using the particle steady flow for high-temperature solar thermal storage. The steady-flow-type particle receiver was designed through visualization of cold model and numerical simulation. The experimental apparatus was fabricated and tested using beam-down sun simulator of 1.0 kWth. The apparatus comprises of the internal-circulating fluidized bed receiver placed between a loop seal with an inlet port and another loop seal with a weir and an exit port of the particles. The tested particles are quartz sand of 0.1 – 0.2 mm and fused brown alumina of 0.09 – 0.1 mm. The experimental set up produces hot particles of quartz sand at 428°C and those of fused brown alumina at 491°C. The highly efficient steady-flow-type particle receiver created steady particle flow smoothly. This apparatus takes in the concentrated light through the quartz window to continuously discharge the particles at high temperatures beyond the criterion in synthesis oil (400°) for solar thermal storage.
Direct Simulation of Volumetric Solar Receiver with Highly Concentrated Radiation
Authors: Nakakura Mitsuho , Matsubara Koji , Bellan Selvan , Kodama Tatsuya 
Published: August 2019

Abstract
The volumetric solar receiver is a promised technology for high-temperature solar absorption in the concentrated solar power, industrial solar thermal usage and solar fuel production. Existing numerical simulation separated computations of light and convective flow and two-way coupling was not perfectly integrated between radiation and convective transport. This paper describes conjugate analysis of radiation, convection and conduction heat transfer in the volumetric receiver for perfect three-way coupling between three mechanisms of heat transfer. The numerical scheme was used for the volumetric receiver with plane surface and that with cut-back inlets for optimization of the geometry. The simulation was made for single cell of honeycomb with 2.4 mm pitch and 0.5 mm wall thickness. Two cases of surface geometry was computed: plane surface; cut-back inlet with 10 mm depth. Basic equations are momentum and energy equations with radiation transport equation. The discrete ordinates method was applied for solving the radiation intensity to consider perfect interaction between radiation, convection and conduction. The material of the receivers are assumed as stainless steel. The numerical simulation demonstrated the superiority of the cut-back receiver which increased the exit temperature by 30 K and decreased 2 Pa for the smallest beam angle of 10°. The contour plot of total heat flux on the wall revealed that the shadow effect was attenuated by the cut-back inlet leading to heat transfer enhancement. The novelties of this work are to treat perfect interaction between radiation and convection in volumetric receiver and to demonstrate the excellence of cut-back inlet receivers.
Performance Simulation for Gas Flow through a Porous Media in Packed bed Columns using CFD
Authors: Salim Bded Asaad 
Published: August 2019

Abstract
Two dimensions of Computational Fluid Dynamics simulation for gas flow in the column with filling material as bed at low particle Reynolds numbers and high particle Reynolds numbers have been presented. The simulation test has been done with the column length 0.9 m. Porous media model was used to simulate the gas flow inside porous granular media. Model of standard k-e for the flow turbulent range was used; the difference on the mesh size used to study effect it on the performance of gas flow through porous media. The result of flow rate of the gas was an important variable influencing bed and there are good results between the CFD simulation of pressure drop and the predicted values from Ergun model, and Computational Fluid Dynamics gave us simulation with high details for porous flow in packed bed equipment.
Experimental Study on Tanuma Shale Stability Using Drilling Fluids with Different Additives
Authors: Mohammed Khalid , Alwassiti Asawer A. , Ali Al-Bidry Mayssaa 
Published: August 2019

Abstract
Shale formation is represented as one of the challenge formations during drilling wells because it is a strong potential for wellbore instability. Tanuma formation in Iraqi oil fields (North Rumila) is located at a depth from 2102 m MD – 2126 m MD. It is considered one of the most problematic formations through drilling wells in North Rumila. Most problems of Tanuma shale are sloughing, swelling, caving, cementing problem and casing landing problem caused by the interaction of drilling fluid with the formation. This paper focuses on studying the chemical and minerals properties of Tanuma shale. In addition, study the effect of drilling fluids and additive salts by using different techniques; (XRD, XRF, reflected and transmitted microscope, scanning electron microscope and EDS)Also, the study includes experiments to observe and enhance the shale stability by using two types of drilling fluids, API and polymer type, with different additives. Four types of additives (KCl, NaCl, CaCl2 and Sodium silicate) in different concentrations (0.5, 1, 5 and 10) wt % and different immersion period (1, 24 and 72 hours) were used. The results show that adding 10 wt. % of sodium silicate to API drilling fluid results in a high percentage of shale recovery (77.99%). While, the maximum shale recovery was (79.76%) in polymer drilling fluid type gained by adding 10 wt % of sodium silicate.
Improving Drilling Fluid Properties at High Pressure Conditions Using Selected Nanomaterials
Authors: Sabah Nada , Alswasiti Asawer A. , Salam Massara 
Published: August 2019

Abstract
Drilling fluids with conventional lubricants (including solid and liquid lubricants) will produce lubricant film between drill string and wellbore/casing, but this film will not be strong enough to protect the bit bearing surfaces subjected to high load conditions during the drilling operations, resulting in shortening the life of drill bit. In this research, the possibility of using nanomaterials as extreme pressure lubricants was investigated by adding different concentrations (0.02, 0.05 and 0.1) wt. %of TiO2nanoparticles (NPs) and Cu NP into water- based mud. The lubricating film strength of water based mud samples under extreme pressure conditions were measured using Extreme Pressure (EP) and Lubricity Tester. With the purpose of getting the best performance from extreme pressure lubricants, the effect of nanomaterials on rheological (including plastic viscosity, yield point, apparent viscosity, and gel strength) and filtration (including filtrate loss volume and mud cake thickness) properties were measured. TiO2 NPs and Cu NP showed a good enhancement in lubricating film strength under extreme pressure conditions. The maximum value of lubricating film strength increasing percentage (69.6%) was obtained using TiO2 NPs with concentration of 0.1wt.%.