scholarly journals Numerical and Experimental Investigations of Composite Solar Walls Integrating Sensible or Latent Heat Thermal Storage

2020 ◽  
Vol 10 (5) ◽  
pp. 1854 ◽  
Author(s):  
Enghok Leang ◽  
Pierre Tittelein ◽  
Laurent Zalewski ◽  
Stéphane Lassue
Keyword(s):  
Weather Conditions ◽  
Energy Performance ◽  
Cold Season ◽  
Experimental Investigations ◽  
Small Scale ◽  
Storage Element ◽  
Storage Wall ◽  
And Performance ◽  
Set Up ◽  
Solar Wall

This article studies a composite solar wall with latent storage (TES) designed to heat rooms inside buildings during the cold season. No numerical model of the composite solar wall is currently available in the Dymola/Modelica software library. The first objective of this work is to develop one such model. The article describes the elementary components, along with the equations that allow modeling the heat transfers and storage phenomena governing both the thermal behavior and performance of the solar wall. This model was built by assembling various existing basic elements from the software’s “Building” library (e.g., models of heat transfer by convection, radiation and conduction) and then creating new elements, such as the storage element incorporating the phase change material (PCM). To validate this solar wall model, numerical results are compared to experimental data stemming from a small-scale composite solar wall manufactured in our laboratory, and the experimental set-up could be tested under real weather conditions. After verifying the level of confidence in the model, the energy performance of two solar walls, one with a conventional storage wall (sensible heat storage) the other containing a PCM (the same as in the experiment), are compared. The result indicates that the solar wall incorporating a PCM does not in this case release any more energy in the room to be heated.

Machine for the Hydrostatic Extrusion–Drawing of Wire

1972 ◽  
Vol 186 (1) ◽  
pp. 499-507
Author(s):  
H. Ll. D. Pugh ◽  
P. T. Wilkinson ◽  
M. H. Hodge
Keyword(s):  
Copper Wire ◽  
Research Work ◽  
Hydrostatic Extrusion ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Small Scale ◽  
New Process ◽  
And Performance ◽  
Commercial Applications ◽  
Fine Copper

Research work on hydrostatic extrusion at N.E.L. (National Engineering Laboratory) has led to the development of a new process for producing wire. A detailed account is given of machines specially designed to exploit this process of hydrostatic extrusion–drawing mainly on the production of fine copper wire. A small-scale machine was built to confirm the design and for experimental investigations. The success of this preliminary work has led to the construction of a large prototype production machine for commercial applications. The operation and performance of both machines is described and some experimental results given.

Experimental Studies of Hydrodynamic Properties and Screening of Riser Fairing Concepts for Deep Water Applications

2015 ◽  
Author(s):  
Rolf Baarholm ◽  
Kjetil Skaugset ◽  
Halvor Lie ◽  
Henning Braaten
Keyword(s):  
Experimental Studies ◽  
Real Life ◽  
Cross Flow ◽  
Free Vibrations ◽  
The Body ◽  
Scale Model ◽  
Small Scale ◽  
Structural Fatigue ◽  
And Performance ◽  
Set Up

The VIV oscillations of marine risers are known to increase drag, and lead to structural fatigue. One proven method of suppressing this vibration is the use of fairings and strakes. These coverings essentially modify the flow along the cylinder, tripping the production of Karman vortices so that they act less coherently or far enough downstream so they interact less with the body. The Norwegian Deepwater Programme (NDP) has conducted a project with the objective to develop and qualify effective low drag fairing concepts with respect to VIV mitigation and galloping. Furthermore, emphasis is put on easy handling and installation. This paper describes the work and findings in an early phase of the development. This includes small scale model test campaigns. In addition to the bare riser for reference, the behaviour and performance of a total of 10 different fairing concepts are evaluated. Free oscillation tests are performed in a towing tank, where 2D fairings were tested in a pendulum set-up. The set-up enables free vibrations in up to 3 DOF (in-line and cross-flow vibrations and yaw). Fix tests with the purpose of establishing hydrodynamic coefficients for the various fairings have been performed in a large cavitation tunnel. Clear differences in performance have been noticed; particular for drag and galloping responses. Based on the results from the 2D tests, a screening of the fairing designs has been performed and the findings have set the course for further development of the most promising candidates for real life applications.

Parametric Investigation of Circumferential Grooves on Compressor Rotor Performance

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Yanhui Wu ◽  
Wuli Chu ◽  
Haoguang Zhang ◽  
Qingpeng Li
Keyword(s):  
Numerical Investigation ◽  
High Speed ◽  
Orthogonal Experiment ◽  
Experimental Investigations ◽  
Small Scale ◽  
Stall Margin ◽  
Compressor Rotor ◽  
Set Up ◽  
Compound Effect ◽  
Unloading Effect

This paper presents numerical and experimental investigations about grooved casing treatment with the help of a high-speed small-scale compressor rotor. First, the numerical investigation seeks to offer a contribution of understanding the working mechanism by which circumferential grooves improve stall margin. It is found that stall margin gain due to the presence of circumferential grooves arises from the suction-injection effect and the near-tip unloading effect. Based on that, the philosophy of design of experiment is then set up. Finally, parametric studies are carried out through systematical experiments. It is found that the orthogonal experiment and the factorial analyses are successful in identifying the “best casing configuration” in terms of stall margin improvement. However, the ineffectiveness of the deduction from simulations suggests that the secondary flow circulations on stall margin gain should not be neglected, and the overall contribution of each groove to stall margin gain depends on its unloading effect and the compound effect of suction-injection. Further numerical investigation will focus on how to set up quantitative criteria to evaluate the compound effect of suction-injection and the unloading effect on stall margin gain respectively in each groove.

scholarly journals The Impact of Entrepreneurial Training and Performance of SMEs In Ghana

2020 ◽  
pp. 126-134
Author(s):  
Richard Sarfo Gyasi ◽  
Cai Li ◽  
Isaac Gumah Akolgo ◽  
Yvonne Owusu-Ampomah
Keyword(s):  
Small Scale ◽  
Business Skills ◽  
Training Interventions ◽  
Self Employment ◽  
Entrepreneurial Training ◽  
And Performance ◽  
Set Up ◽  
Economic Landscape ◽  
The Impact

In developing countries such as Ghana, the economic landscape is changing, with a move from foreign direct investment to self-employment and entrepreneurship. Academics, practitioners and governments worldwide increasingly recognized the role of education and training in providing entrepreneurs with the necessary business skills and acumen to plan, set up and grow their business ideas. The main aim of the study is to investigate the impact of entrepreneurial training intervention on innovations and performance of small scale automobile businesses in Ghana. Data was collected from small scale automobile business owners and managers in Kumasi Metropolis in the Ashanti Region of Ghana. The convenient sampling method was used to select eight hundred and ninety-six (896) respondents for the study. The data was analyzed meaningfully following the appropriate protocols by categorizing and coding. The Statistical Package for Social Science (SPSS) version 21.0, SMART PLS 3.2.8 and Microsoft Excel 2007 were used in analyzing the data. The study reveals that; there is a significant relationship between entrepreneurial training interventions and performance of small scale automobile firms in Ghana.

Optimization of the Installation of an Earth-to-Air Heat Exchanger and Detailed Design of a Dedicated Experimental Set-Up

2014 ◽  
Vol 501-504 ◽  
pp. 2158-2161 ◽  
Author(s):  
Salvatore Carlucci ◽  
Giulio Cattarin ◽  
Lorenzo Pagliano ◽  
Marco Pietrobon
Keyword(s):  
Warm Season ◽  
Energy Performance ◽  
Primary Energy ◽  
Cold Season ◽  
Hvac Systems ◽  
Thermal Capacity ◽  
Peak Loads ◽  
Set Up ◽  
Simple Technology ◽  
Selection Of

Earth-to-Air Heat Exchangers (EAHE) represent a relatively simple technology that can be easily coupled with traditional HVAC systems as well as with hybrid systems in order to exploit the thermal capacity of the ground. The air is pre-heated in the cold season and pre-cooled in the warm season through the EAHE, thus smoothing the peak loads and reducing the primary energy consumption. The present paper presents an experimental set-up of an EAHE implemented in a rural area in the Sicily region, focusing on the selection of the type of soils and the characteristics of the monitoring system installed to collect information on the actual energy performance of the EAHE.

scholarly journals Thermal behaviour of green façades in summer

2018 ◽  
Vol 49 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Ileana Blanco ◽  
Evelia Schettini ◽  
Giacomo Scarascia Mugnozza ◽  
Giuliano Vox
Keyword(s):  
Plant Species ◽  
Thermal Behaviour ◽  
Building Energy ◽  
Energy Performance ◽  
Cold Season ◽  
Small Scale ◽  
Urban Heat ◽  
Wind Barrier ◽  
The University ◽  
New Buildings

Building greenery systems can represent a sustainable solution for new buildings design and for existing buildings retrofitting, in order to improve the thermal energy performance of buildings, to decrease building energy loads and to contrast the Urban Heat Island. Green façades can influence thermal properties of a building by means of different important mechanisms: the shading, the cooling, the insulating and the wind barrier effect. Moreover, green façades accomplish heating effect in the cold season and at nighttime. An experimental test was developed at small scale at the University of Bari (Italy) from 2014 to 2016 for testing two different green façades. The plant species chosen were Pandorea jasminoides variegated and Rhyncospermum jasminoides, two evergreen climbing plants. A third uncovered wall was used as control. The thermal behaviour of the plants was analysed during the 2016 summer season, by keeping in consideration the external surface temperature of the building and the temperature of the airgap behind the green vertical systems. The daylight temperatures observed on the plant-covered walls during representative days were lower than the respective temperatures of the uncovered wall up to 7.0°C. During nighttime, the temperatures behind the plants were higher than the respective temperatures of the control wall up to 2.2°C. The results shown in the present research allow delineating the behaviour of the two plant species during summer in the Mediterranean climate region.

scholarly journals Impact of Air Infiltration on IAQ and Ventilation Efficiency in Higher Educational Classrooms in Spain

2021 ◽  
Vol 13 (12) ◽  
pp. 6875
Author(s):  
Irene Poza-Casado ◽  
Raquel Gil-Valverde ◽  
Alberto Meiss ◽  
Miguel Ángel Padilla-Marcos
Keyword(s):  
Natural Ventilation ◽  
Well Being ◽  
Cold Season ◽  
Climate Conditions ◽  
Air Infiltration ◽  
Ventilation Efficiency ◽  
Educational Buildings ◽  
Set Up ◽  
Total Volatile Organic Compounds ◽  
The Impact

Indoor air quality (IAQ) in educational buildings is a key element of the students’ well-being and academic performance. Window-opening behavior and air infiltration, generally used as the sole ventilation sources in existing educational buildings, often lead to unhealthy levels of indoor pollutants and energy waste. This paper evaluates the conditions of natural ventilation in classrooms in order to study how climate conditions affect energy waste. For that purpose, the impact of the air infiltration both on the IAQ and on the efficiency of the ventilation was evaluated in two university classrooms with natural ventilation in the Continental area of Spain. The research methodology was based on site sensors to analyze IAQ parameters such as CO2, Total Volatile Organic Compounds (TVOC), Particulate Matter (PM), and other climate parameters for a week during the cold season. Airtightness was then assessed within the classrooms and the close built environment by means of pressurization tests, and infiltration rates were estimated. The obtained results were used to set up a Computational Fluid Dynamics (CFD) model to evaluate the age of the local air and the ventilation efficiency value. The results revealed that ventilation cannot rely only on air infiltration, and, therefore, specific controlled ventilation strategies should be implemented to improve IAQ and to avoid excessive energy loss.

scholarly journals Prediction of Pest Insect Appearance Using Sensors and Machine Learning

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4846
Author(s):  
Dušan Marković ◽  
Dejan Vujičić ◽  
Snežana Tanasković ◽  
Borislav Đorđević ◽  
Siniša Ranđić ◽  
...  
Keyword(s):  
Machine Learning ◽  
Relative Humidity ◽  
Weather Conditions ◽  
Daily Basis ◽  
Machine Learning Algorithms ◽  
Lower Percentage ◽  
Timely Manner ◽  
Proposed Model ◽  
Set Up ◽  
Accuracy Of Prediction

The appearance of pest insects can lead to a loss in yield if farmers do not respond in a timely manner to suppress their spread. Occurrences and numbers of insects can be monitored through insect traps, which include their permanent touring and checking of their condition. Another more efficient way is to set up sensor devices with a camera at the traps that will photograph the traps and forward the images to the Internet, where the pest insect’s appearance will be predicted by image analysis. Weather conditions, temperature and relative humidity are the parameters that affect the appearance of some pests, such as Helicoverpa armigera. This paper presents a model of machine learning that can predict the appearance of insects during a season on a daily basis, taking into account the air temperature and relative humidity. Several machine learning algorithms for classification were applied and their accuracy for the prediction of insect occurrence was presented (up to 76.5%). Since the data used for testing were given in chronological order according to the days when the measurement was performed, the existing model was expanded to take into account the periods of three and five days. The extended method showed better accuracy of prediction and a lower percentage of false detections. In the case of a period of five days, the accuracy of the affected detections was 86.3%, while the percentage of false detections was 11%. The proposed model of machine learning can help farmers to detect the occurrence of pests and save the time and resources needed to check the fields.

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