scholarly journals Numerical and experimental investigation on the thermal behaviour of the building integrating occupant thermal comfort

2020 ◽  
Vol 307 ◽  
pp. 01025 ◽  
Author(s):  
Abed Al Waheed Hawila ◽  
Abdelatif Merabtine ◽  
Nadège Troussier
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Thermal Behaviour ◽  
Room Temperature ◽  
Maximum Error ◽  
Measured Data ◽  
Influential Factor ◽  
Simulation Tools ◽  
Good Agreement

Simulation tools are widely used to model buildings in order to predict their indoor air quality and energy consumption. The prediction capability of the model is an influential factor in determining the ability of the building to be energy efficient and thermally comfortable. Thus, the validation of the developed models is crucial. In this context, this paper presents a numerical model developed using an object-oriented modelling tool based on the Modelica approach and a case study validation of this model. Then the thermal behaviour of the building and the occupants’ thermal comfort in the considered case study are investigated. The objective is to validate the developed model firstly by comparing predicted results with measured data regarding room temperature and relative humidity, and secondly by comparing the calculated thermal comfort indices (PMV and PPD) based on predicted results and measured data. The results show good agreement between simulations and experiments, with a maximum error in room temperature and relative humidity of 1.7 °C and 4.5%, respectively, and only 1% and 1.5% difference between averaged values of PMV and PPD, respectively.

scholarly journals An Improved PV Output Forecasting Model by Using Weight Function: A Case Study in Cambodia

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Songkiate Kittisontirak ◽  
Aekkawat Bupi ◽  
Perawut Chinnavornrungsee ◽  
Kobsak Sriprapha ◽  
Pairash Thajchayapong ◽  
...  
Keyword(s):  
Weight Function ◽  
High Accuracy ◽  
Measured Data ◽  
Forecasting Model ◽  
Pv Module ◽  
Improve Accuracy ◽  
Software Programs ◽  
One Year ◽  
Good Agreement

This paper proposes a new concept to improve accuracy of PV forecasting model. The model was implemented by MATLAB/Simulink software using solar irradiance and module temperature as measurement parameters for calculation. The model was developed by single-diode equivalent circuits (5-p model) for simulated PV module power output and compared with other software programs for validation which showed correct PV characteristics. To achieve high accuracy, the model was improved by weight function using one-year measured data. The accuracy of our developed model was verified by comparison with four commercial simulator software programs and the results from real system which were measured and recorded for 1 year. It was found that the model output was in a good agreement with the measured data. This research can be utilized in another area by adjusting the PV equation with weight function of that area.

scholarly journals Hygrothermal study of dwelling submitted to passive cooling

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2597-2604
Author(s):  
Razika Kharchi ◽  
Khaled Imessad
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Natural Ventilation ◽  
Energy Savings ◽  
Pilot Project ◽  
Passive Cooling ◽  
Free Cooling ◽  
Air Conditioning Systems ◽  
Good Agreement

A significant portion of energy consumed in buildings is due to energy usage by heating, ventilation, and air conditioning systems. Free cooling is a good option for energy savings in the systems. In recent years, scientists, engineers, and architects designed successful and innovative buildings which use passive cooling techniques, such as natural ventilation. The house studied in the present work, is a pilot project undertaken jointly by the Centre for Development of Renewable Energies (CDER) and the National Centre for Studies and Research of the integrated building (CNERIB) in the framework of the MED-ENEC project (Mediterranean Energy Efficiency in Construction structure). The house under consideration has a surface area of 65 m2 and is located in the region of Algiers which characterized by a Mediterranean climate with relatively mild winters and a hot and humid summer. The aim of this work is to study the thermal comfort inside the house in summer without air conditioning systems, only ventilation is considered. The aim of this work is to study the effect of natural ventilation on both thermal and hygrometric comfort inside the house during the summer period. Numerical simulation is made using the TRNSYS software and the results obtained are in good agreement with measured values. The prototype home is designed in a way that natural ventilation allows thermal comfort which induced energy saving from air conditioning. The mean temperature measured in the interior of the house is 26?C. The relative humidity reaches about 70% in August. Thermal comfort is related to relative humidity that are the essential parameters of the feeling of comfort. Humidity is an important parameter in thermal comfort, it is why we can conclude that we have reached a relatively good hygrothermal comfort.

scholarly journals Thermal Comfort At The Street Corridor Around Public Places, Case Study Alun-Alun Malang City

2016 ◽  
Vol 3 (4) ◽  
pp. 177 ◽  
Author(s):  
Erna Winansih ◽  
Antariksa Antariksa ◽  
Surjono Surjono ◽  
Amin Setyo Leksono
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
The South ◽  
Index Method ◽  
Public Places ◽  
South Side ◽  
Temperature Humidity Index ◽  
Humidity Index

Malang as the second largest city in East Java province become crowded recently. The congestion almost happens everyday. The scenery of the street corridor is full of iron stacks. It is said that Malang city is less comfortable and less walkable. The decrease of this environment encourages to conduct the study (Q.S. 16:90, Q.S. 96:1-5, Q.S. 30:41). The study aimed to analyze the thermal comfort at pedestrian ways around Malang city squares, the street corridor of Merdeka Alun-Alun (MAA) and the Tugu Alun-Alun (TAA). The temperature and relative humidity were measured by multinorm instrument. The THI (Temperature Humidity Index) method was used to analyze the thermal comfort. The results showed that the THI average at TAA (27) were more comfortable than at MAA (27,5). The south side of the MAA corridor became the most comfortable with the THI value of 26,4, which the side covered by trees canopy (Q.S. 7:58). It needs to conduct next research (Q.S. 13:11), because of the change of the activities at these street corridors.

scholarly journals Multi-Physics Tool for Electrical Machine Sizing

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1651 ◽  
Author(s):  
Yerai Moreno ◽  
Gaizka Almandoz ◽  
Aritz Egea ◽  
Patxi Madina ◽  
Ana Julia Escalada
Keyword(s):  
Magnetic Flux ◽  
Maximum Error ◽  
Analytical Models ◽  
Electrical Machine ◽  
Element Analysis ◽  
Efficient Procedure ◽  
Lumped Parameter ◽  
One Machine ◽  
Good Agreement

Society is turning to electrification to reduce air pollution, increasing electric machine demand. For industrial mass production, a detailed design of one machine is usually done first, then a design of similar machines, but different ratings are reached by geometry scaling. This design process may be highly time-consuming, so, in this paper, a new sizing method is proposed to reduce this time, maintaining accuracy. It is based on magnetic flux and thermal maps, both linked with an algorithm so that the sizing process of an electrical machine can be carried out in less than one minute. The magnetic flux maps are obtained by Finite Element Analysis (FEA) and the thermal maps are obtained by analytical models based on Lumped Parameter Circuits (LPC), applying a time-efficient procedure. The proposed methodology is validated in a real case study, sizing 10 different industrial machines. Then, the accuracy of the sizing tool is validated performing the experimental test over the 10 machines. A very good agreement is achieved between the experimental results and the performances calculated by the sizing tools, as the maximum error is around 5%.

scholarly journals A parametric building energy simulation case study on the potential and limitations of passive design in the Mediterranean climate of Malta

2018 ◽  
Vol 3 ◽  
pp. 4 ◽  
Author(s):  
Heinrich Manz ◽  
Daniel Micallef ◽  
Simon Paul Borg ◽  
Vincent Buhagiar
Keyword(s):  
Thermal Comfort ◽  
Room Temperature ◽  
Mediterranean Climate ◽  
Building Design ◽  
Building Energy ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Artificial Heating ◽  
The Impact

The present case study sets out to investigate the potential and limitations of passive building design in a typical Mediterranean climate. The Maltese Islands were taken as the case study location. Assuming a fully detached, cuboid-shaped, generic multi-storey office building, one representative storey was modelled by means of the building energy simulation code WUFI®Plus. Thermal comfort was analysed based on the adaptive acceptable operative room temperature concept of EN 15251 for buildings without mechanical cooling systems. Assuming neither artificial heating nor cooling, the free-running operative room temperature was evaluated. By means of a parametric study, the robustness of the concept was analysed and the impact of orientation, window to wall area ratio, glazing, shading, thermal insulation, nighttime ventilation and thermal mass on the achievable level of thermal comfort is shown and discussed. It is concluded that in a well-designed building and by means of decent insulation (present case: Uwall = 0.54 W/(m2 · K)), double glazing, variable external shading devices and passive cooling by nighttime ventilation, a high level of thermal comfort is achievable in this climate using only very minor amounts of energy for artificial heating and cooling or possibly even none at all.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

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