445 results on '"chauffage"'
Search Results
2. Estimation of Ranque-Hilsch vortex tube performance by machine learning techniques.
- Author
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Doğan, Ayhan, Korkmaz, Murat, and Kirmaci, Volkan
- Subjects
- *
VORTEX tubes , *MACHINE learning , *MACHINE performance , *KRIGING , *SUPPORT vector machines , *WORKING fluids - Abstract
• The performance of counter-flow Ranque-Hilsch Vortex Tube (RHVT) was modelled with respect to pressure, working fluid and nozzle specifications. • Linear Regression (LR), Support Vector Machines (SVM), Gaussian Process Regression (GPR), Regression Trees (RT) and Ensembles of Trees (ET) prediction methods were used. • Optimizing the performance of counter-flow RHVT, it is aimed to fill the gap in the literature by using LR, SVM, GPR, RT and ET methods among the machine learning methods. This study planned to model a counter-flow Ranque-Hilsch Vortex Tube (RHVT) using compressed air and oxygen gas by machine learning to separate the thermal temperature. From within machine learning models, Linear Regression (LR), Support Vector Machines (SVM), Gaussian Process Regression (GPR), Regression Trees (RT), and Ensemble of Trees (ET) were preferred. By leaving the outlet control valve on the hot fluid side fully open, data were received for each material and nozzle at RHVT with inlet pressure starting from 150 kPa and up to 700 kPa at 50 kPa intervals. In the counter flow RHVT, the lack in the literature has been tried to be eliminated by modeling the RHVT by finding the difference (ΔT) between the temperature of the cold flow exiting (T c) and the temperature of the leaving hot flow (T h). When analyzing each of the machine learning models in the study, 80% of all data was used as training data, 20% of all data was used for the test, 70% of all data was used as training data, and 30% of all data was used for the test. As a result of the analysis, when both air and oxygen fluids were used, the GPR method gave the best result with 0.99 among the machine learning models in two different test intervals of 70%–30% and 80%–20%. The success of other machine learning models differed according to the fluid and model used. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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3. Normes de chauffe et transition énergétique : les transactions des habitants
- Author
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Fijalkow Yankel and Maresca Bruno
- Subjects
environnement ,technologies ,transition énergétique ,habitat ,chauffage ,Science ,Social Sciences - Abstract
On interroge dans cet article la notion de transition énergétique en explorant la non-prise en compte par les pouvoirs publics de l’écart entre les pratiques de chauffage des ménages et les dispositifs d’injonctions mis en œuvre. Après avoir discuté les résultats d’enquêtes récentes sur les températures de chauffe des ménages, on revisite l’évolution et le mode de production des normes de confort dans l’habitat et on analyse les pratiques de chauffage à l’aune de la notion de transaction sociale. Les pratiques des ménages, qui conduisent à des températures réelles de chauffe des habitations plus élevées que les 19 degrés de la norme, constituent une critique de fait de la transition énergétique. Ne parvenant pas à « faire passer la norme » dans les comportements en dépit des urgences de la maîtrise de la demande en énergie, la transition énergétique se révèle velléitaire par ignorance des mécanismes de la pratique sociale.
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- 2019
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4. Effect of heat treatment and heat treatment in combination with lignosulfonate on in situ rumen degradability of canola cake crude protein, lysine, and methionine.
- Author
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Micek, Piotr, Słota, Katarzyna, and Górka, Paweł
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METHIONINE ,HEAT treatment ,TREATMENT effectiveness ,SULFONATES ,LYSINE ,PROTEOLYSIS - Abstract
Copyright of Canadian Journal of Animal Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2020
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5. Etude et calcul de bilan de la densité du flux solaire pour un simple habitat dans la région d’Adrar
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A. Oudrane, B. Aour, B. Zeghmati, X. Chesneau, and M. Hamouda
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densité du flux solaire ,adrar ,chauffage ,climatique ,désertique ,bâtiment ,Renewable energy sources ,TJ807-830 - Abstract
L’objectif principal de ce travail est d’étudier l’effet des conditions climatiques externes, sur l’évolution de la densité du flux solaire journalier incident sur les parois verticales d’un bâtiment situé dans la région d’Adrar au Sud de l’Algérie avec diffèrent orientation. Ce bâtiment est conçu pour des a1pplications de type chauffage ou climatisation. Les simulations numériques abordées dans ce travail ont permis de comparer la variation de la densité du flux solaire incident durant une journée complète sur les parois Sud, Est, Nord et Ouest du bâtiment aux valeurs du flux solaire global sur une paroi horizontale (le plafond externe). Le flux solaire global horizontal est calculé à l’aide d’une fonction Gaussienne sinusoïdale. Les simulations ont été effectuées dans le cas d’un bâtiment situé dans une zone désertique. Les résultats de la simulation numérique, ont montré l’effet de l’orientation du bâtiment sur l’évolution du flux solaire journalier incident.
- Published
- 2017
6. Experimental analysis of cooling and heating performance of serial and parallel connected counter-flow Ranquee–Hilsch vortex tube systems using carbon dioxide as a working fluid.
- Author
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Kaya, Hüseyin, Uluer, Onuralp, Kocaoğlu, Evren, and Kirmaci, Volkan
- Subjects
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VORTEX tubes , *CARBON dioxide , *HEAT pipes , *WORKING fluids , *SEPARATION of gases , *FLOW meters , *SYSTEM analysis - Abstract
• The highest Δ T was highest as 76.9 K in parallel connected RHVT system. • The most efficient case in this study brass-six nozzle at 550 kPa. • CO 2 provides higher thermal separation than air. This study examines the performance analysis of two counter flow Ranquee–Hilsch Vortex Tubes (RHVT) having the same geometrical properties in the condition of serial and parallel connection. The performance of CO 2 as a working fluid in the vortex tube by using nozzles having 2,4 and 6 orifices, which were manufactured from polyamide and brass material has been experimentally investigated. Experimental studies were carried out by compressing CO 2 through the compressor to the vortex tube at pressures between 150 and 550 kPa. The most important physical property of a RHVT is the ratio of L/D which is equal to 14 in this study. In addition, by using the data obtained from experimental results, the second law efficiency was calculated for different working conditions of the systems by exergy analysis. The highest overall temperature difference (Δ T) was obtained as 76.9 K when using parallel connected RHVT system with brass-six nozzle. [ABSTRACT FROM AUTHOR]
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- 2019
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7. Simulation of heat pumps for simultaneous heating and cooling using CO2.
- Author
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Diaby, Ahmadou Tidiane, Byrne, Paul, and Maré, Thierry
- Subjects
- *
HEAT pumps , *HOT water , *WASTE heat , *KEY performance indicators (Management) , *EXERGY , *COOLING - Abstract
• A model of a CO 2 heat pump is described. • A first model simulates a heat pump for simultaneous heating and cooling. • A second model simulates a heat pump for simultaneous cooling and desalination. • CO 2 proposes new interesting applications for multi-function heat pumps. This article presents the numerical model of a heat pump using CO 2 in a transcritical cycle. Two systems are envisaged in this work: a heat pump for simultaneous heating, cooling and domestic hot water (HPS1) and a heat pump for simultaneous cooling and desalination (using heat) (HPS2). The simulation study uses EES and TRNSYS to assess the performance of two heat pumps in different applications and operating conditions. The simulations show interesting performance indicators: the seasonal COP for heating and cooling and the exergy efficiency for both systems. HPS2 producing cooling and desalination has a higher seasonal process exergy efficiency than HPS1 due to the interesting use of energy for the desalination application. The performance analysis presents a seasonal Coefficient of Performance (COP) between 2 and 3. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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8. R744 booster integrated system for full heating supply to supermarkets.
- Author
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D'Agaro, Paola, Cortella, Giovanni, and Polzot, Alessio
- Subjects
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ENERGY consumption for refrigerators , *HEAT recovery , *ENERGY conservation , *SPACE heaters , *SPACE cooling - Abstract
Highlights • Synergy between CO 2 commercial refrigeration systems and heating plants allows energy savings. • Configurations where heat recovery is promoted are investigated through modelling. • Full supply of heating and DHW demands is feasible and energy effective at mild and warm climates. • An additional outdoor evaporator is employed to supply heat. Abstract In warm climates carbon dioxide (R744) refrigeration systems are known to perform worse because of the transcritical operation which occurs for a large part of the year, increasing substantially their energy use. On the other hand, the high discharge temperature potentially allows recovering a large amount of heat at various temperature levels. This paper investigates the energy performance of a R744 refrigeration system which provides a medium-sized supermarket with DHW and space heating, besides satisfying the cooling load required by the chilled and frozen food storage and display equipment. The system is controlled to meet the full heating demand of the building and is equipped with an additional air-cooled evaporator, which can be used as a supplemental heat source. Dynamic simulations of the refrigeration system, including mutual interactions with the building and the HVAC, are carried out at three climate conditions. The results are compared to alternative refrigeration systems not controlled by the heating demand, such as the R744 booster system itself, a R404A direct expansion system and a R134a/R744 cascade system, where heat pumps are employed for heating. Energy saving was predicted both when compared to the CO 2 system (up to 4.5%), and to the HFC systems (up to 16%). Furthermore, the heating COP of the integrated system appears to be always higher than that of standalone heat pumps. The comparison shows that heat recovery can fully supply refrigeration and heating needs of the supermarket with reduced running and possibly investment costs when compared to separate systems. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
9. The Historical Transition from Coal to Hydrocarbons: Previous Explanations and the Need for an Integrative Perspective.
- Author
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Melsted, Odinn and Pallua, Irene
- Subjects
- *
HYDROCARBONS , *RENEWABLE energy transition (Government policy) , *RESIDENTIAL heating systems , *NATURAL gas , *POWER resources - Abstract
The article deals with the historical transition from coal to oil and natural gas, commonly referred to as hydrocarbons. This transition occurred throughout the industrialized world between the 1940s and 1970s, yet the causes for the shift from coal to hydrocarbons are only marginally understood. Drawing from recent research on historical energy transitions, we examine the takeover of hydrocarbons in the context of the incumbent coal configurations. Building on previous explanations, we identify two analytical perspectives: (1) the view on the overall energy supply system that diversified when hydrocarbons were introduced, and (2) that on the consumers of energy, who replaced coal with hydrocarbon alternatives. The central argument is that the two perspectives need to be integrated to fully understand why hydrocarbons could replace coal. This monumental change in energy history was no simple shift in fuels, but a complex transition that occurred at (1) the level of energy supply, where hydrocarbons became available as alternatives to coal, and (2) the level of energy consumption, where consumers in the areas of railway and maritime transportation, residential heating, industrial production, and electricity generation actively decided to use hydrocarbon alternatives as substitutions for coal. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
10. SLOWHEAT@LOCI-LAB
- Author
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Van Moeseke, Geoffrey and UCL - SST/LAB - Louvain research institute for Landscape, Architecture, Built environment
- Subjects
confort ,IEQ ,chauffage ,slowheat ,bâtiment - Abstract
Slowheat@LOCILAB est une expérience visant à mesurer l’impact sur le confort de modifications des « usages thermiques ». Elle s’est déroulée dans les espaces de travail (bureaux) de la faculté LOCI et de l’institut LAB de l’UCLouvain, en décembre et janvier 2023. L’objectif de cette expérience est de démontrer qu’il est possible de maintenir la satisfaction des occupants tout en abaissant les températures intérieures des espaces de travail, grâce à l’utilisation de systèmes de correction thermique individuels. Le présent rapport conclut l’expérience et formule des recommandations pour une élargissement de cette pratique de chauffage au sein de l’UCLouvain.
- Published
- 2023
11. Slowheat@LOCI
- Author
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UCL - SST/LAB - Louvain research institute for Landscape, Architecture, Built environment, Van Moeseke, Geoffrey, UCL - SST/LAB - Louvain research institute for Landscape, Architecture, Built environment, and Van Moeseke, Geoffrey
- Abstract
Slowheat@LOCI est une expérience visant à mesurer l’impact sur le confort et les consommations d’énergie de modifications des « usages thermiques ». Elle s’est déroulée sur le site de Saint-Gilles de la Faculté d’Architecture, d’Ingénierie Architecturale, d’Urbanisme (LOCI) de l’UCLouvain, en février et mars 2022. L’objectif de cette expérience est de démontrer qu’il est possible de maintenir la satisfaction des occupants tout en réalisant d’importantes économies d’énergie, grâce à une réflexion sur les conditions d’ambiance offertes par le bâtiment. En particulier, dans notre cas, il s’agit de sortir de l’uniformité des températures (globalement, tout le bâtiment est chauffé de la même façon), pour trouver une meilleur correspondance entre ambiances, espaces et usages. Le présent rapport conclut la première phase de l’expérience, et formule des recommandations portant sur la gestion thermique de ce bâtiment particulier, la définition d’expériences complémentaires, et la généralisations de pistes d’intervention sur d’autres sites de l’UCLouvain.
- Published
- 2022
12. Code national de l'énergie pour les bâtiments : Canada : 2020
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Commission canadienne des codes du bâtiment et de prévention des incendies
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CNRCCode ,CNRCCode2020 ,Codes & guides ,ventilation ,building ,chauffage ,heating ,air conditioning ,bâtiment ,Codes et guides ,energy ,énergie ,conditionnement d’air - Abstract
Le Code national de l’énergie pour les bâtiments – Canada (CNÉB) 2020 est élaboré par la Commission canadienne des codes du bâtiment et de prévention des incendies, avec le soutien de Ressources naturelles Canada, et publié par le Conseil national de recherches du Canada. Il renferme les dispositions techniques visant la conception et la construction écoénergétiques de bâtiments neufs et d’agrandissements. De nombreuses modifications techniques ont été incorporées dans cette nouvelle édition du CNÉB afin de rehausser le niveau d’efficacité énergétique exigé dans le code et d’élargir les options de conformité. Principales modifications incorporées dans le CNÉB 2020 • Le domaine d’application du CNÉB est élargi de manière à inclure les transformations apportées aux bâtiments initialement construits conformément au CNÉB, comme les améliorations effectuées par un locataire. • Les valeurs maximales du coefficient de transmission thermique globale pour les ensembles de construction opaques et le fenêtrage sont réduites afin d’améliorer la performance thermique de l’enveloppe du bâtiment. • La solution des essais d’étanchéité à l’air sur l’ensemble du bâtiment est introduite afin de permettre la conformité aux exigences d’étanchéité à l’air. • Les densités de puissance de l’éclairage sont mises à jour de manière à refléter l’efficacité accrue des produits d’éclairage. • Les exigences de performance pour l’équipement de chauffage, de ventilation et de conditionnement d’air (CVCA) et l’équipement de chauffage de l’eau sanitaire sont modifiées aux fins d’harmonisation avec les normes et règlements pertinents. • La méthode des solutions de remplacement pour les installations CVCA et les installations d’eau sanitaire, dont l’usage était peu répandu et qui était d’une grande complexité, a été retirée. • Une nouvelle méthode de conformité comportant quatre paliers de performance énergétique est introduite afin de servir de cadre pour l’amélioration de l’efficacité énergétique dans les bâtiments., Première impression, Sur la couverture intérieure : Première édition 1997. Deuxième édition 2011. Troisième édition 2015. Quatrième édition 2017. Cinquième édition 2020, For questions about Code licensing, sales, technical support, to obtain accessible copies, or to learn about other accommodations, please contact the NRC's Codes Canada team: (https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/help-using-accessing-codes/contact-codes-canada), Pour des questions relatives aux codes ou aux licences, aux ventes et au soutien technique qui s'y rapportent, pour l'obtention d'une copie accessible ou pour en savoir plus sur d'autres mesures d'adaptation, prière de communiquer avec l'équipe de Codes Canada au CNRC : (https://nrc.canada.ca/fr/certifications-evaluations-normes/codes-canada/aide-lutilisation-laccessibilite-codes/communiquer-codes-canada), For questions or comments about the content of the Codes and User’s Guides, please contact the CBHCC Secretary ., Veuillez adresser toute question ou tout commentaire au sujet du contenu des codes et des guides de l’utilisateur au Secrétaire du CCHCC .
- Published
- 2022
13. National Energy Code of Canada for Buildings: 2020
- Author
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Canadian Commission on Building and Fire Codes
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Codes & guides ,ventilation ,building ,NRCCode ,chauffage ,heating ,air conditioning ,bâtiment ,Codes et guides ,NRCCode2020 ,energy ,énergie ,conditionnement d’air - Abstract
The National Energy Code of Canada for Buildings (NECB) 2020, developed by the Canadian Commission on Building and Fire Codes with the support of Natural Resources Canada, and published by the National Research Council of Canada, sets out technical requirements for the energy-efficient design and construction of new buildings and additions. Several technical changes have been incorporated in this new edition, improving the level of energy efficiency provided by the Code and expanding compliance options. Significant changes in the NECB 2020 • The application of the Code is extended to cover alterations, such as tenant improvements, to buildings originally constructed in accordance with the NECB. • Maximum overall thermal transmittance values for opaque building assemblies and fenestration are reduced to improve the thermal performance of the building envelope. • Whole-building airtightness testing is introduced as an option for complying with air leakage requirements. • Lighting power densities are updated to reflect improvements in the efficacy of lighting products. • Performance requirements for heating, ventilating and air-conditioning (HVAC) and service water heating equipment are updated to align them with relevant standards and regulations. • The trade-off compliance paths for HVAC and service water systems, which were complex and not widely used, are removed. • A new compliance path with 4 energy performance tiers is introduced to provide a framework for achieving higher levels of energy efficiency in buildings., First printing., On inside cover: First Edition 1997. Second Edition 2011. Third Edition 2015. Fourth Edition 2017. Fifth Edition 2020., For questions about Code licensing, sales, technical support, to obtain accessible copies, or to learn about other accommodations, please contact the NRC's Codes Canada team: (https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/help-using-accessing-codes/contact-codes-canada), Pour des questions relatives aux codes ou aux licences, aux ventes et au soutien technique qui s'y rapportent, pour l'obtention d'une copie accessible ou pour en savoir plus sur d'autres mesures d'adaptation, prière de communiquer avec l'équipe de Codes Canada au CNRC : (https://nrc.canada.ca/fr/certifications-evaluations-normes/codes-canada/aide-lutilisation-laccessibilite-codes/communiquer-codes-canada), For questions or comments about the content of the Codes and User’s Guides, please contact the CBHCC Secretary ., Veuillez adresser toute question ou tout commentaire au sujet du contenu des codes et des guides de l’utilisateur au Secrétaire du CCHCC .
- Published
- 2022
14. Experimental investigation on the influence of high temperature on viscosity, thermal conductivity and absorbance of ammonia–water nanofluids.
- Author
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Jiang, Weixue, Du, Kai, Li, Yanjun, and Yang, Liu
- Subjects
- *
NANOFLUIDS , *ABSORPTION , *REFRIGERATION & refrigerating machinery , *THERMAL conductivity , *HYSTERESIS - Abstract
To select the optimal ammonia–water nanofluids and apply to ammonia–water absorption refrigeration systems (AARS), this paper investigated the influence of heating on viscosity, thermal conductivity and absorbance of binary nanofluids. The hysteresis phenomenon was observed after heating at high temperature which is rarely reported in the literature. Experimental results show that most of nanofluids' thermal conductivity increased by about 3–12% after heating. However, their viscosities increased by as much as 15% to 25% except the γ-TiO 2 ammonia–water nanofluid, which was reduced by 2% to 7%. This study also shows that the trend of viscosity is consistent with the absorbance. Due to fact that the thermal conductivity of γ-TiO 2 /NH 3 –H 2 O mixture increased after heating, while the viscosity decreased, even if the concentration of the base liquid is 12.5% or 25%, therefore it is the optimal choice for practical research in AARS at present. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
15. Performance comparison of absorption heating cycles using various low-GWP and natural refrigerants.
- Author
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Wu, Wei, Zhang, Haiyang, You, Tian, and Li, Xianting
- Subjects
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HEAT radiation & absorption , *WORKING fluids , *REFRIGERANTS , *THERMODYNAMIC cycles , *CRYSTALLIZATION - Abstract
Absorption heating is potential in building energy saving and emission reduction. To overcome the problems of conventional absorption working fluids and to explore more alternatives, absorption heating cycles using various low-GWP and natural refrigerants are compared. Property models of different working fluids have been chosen and developed with good accuracies. The models of single-effect and compression-assisted cycles are built with verified accuracies. Simulations revealed that H 2 O–LiBr has the best heating performance, but is highly restricted by crystallization and freezing. NH 3 –H 2 O has good performance and wide applicable range, but has the concern of toxicity. Among the HFC-based fluids, R161-DMF has the highest COP of 1.448–1.496 when generation temperature is above 145 °C, 1.414–1.674 when evaporation temperature is above 8 °C, 1.745–1.409 when condensation temperature is below 52 °C, otherwise R152a-DMF performs the best. R134a-DMF has quite similar performance to R152a-DMF, while R32-DMF has the lowest COP in the whole temperature ranges. In the compression-assisted cycle, the minimum generation temperature can be reduced from 92–130 °C to 65–80 °C, and the minimum evaporation temperature can be reduced from −8 to 6 °C to −20 to −12 °C under a compression ratio of 2.0. Primary energy efficiency of R161-DMF can be increased to 1.146–1.327 under generation temperature of 65–130 °C, and to 1.117–1.330 under evaporation temperature of −10 to 10 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
16. The Influence of Active Warming up, with or without Static Stretching, on Muscular Strength in Brazilian Militaries.
- Author
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de Oliveira, Rafael Melo, Lermen, Daniel Carreiro, Marson, Runer Augusto, and Neves, Eduardo Borba
- Subjects
- *
MUSCLE strength , *KNEE , *DYNAMOMETER - Abstract
The aim of this study was to compare the influence of active warm-up with or without static stretching on torque values generated in equipment isokinetic to knee joint. It was a cross-section study, comparative, which evaluated the maximum strength of knee extensors and flexors on an isokinetic dynamometer at the speed of 60°/s. Twelve (12) military were evaluated, all sex male, with average age group of 25 years old ±2.5; in relation to a body mass and stature, the average values and standard deviation were 75 ± 7.5 Kg e 1.71 ± 0.1 m. Significant differences were observed on peak torque values of the knee extensors (p=0.034), knee flexors (p=0.028) and maximum peak torque values of knee flexors (p=0.034) between the tests preceded by warm-up with static stretching and the ones preceded by warm-up without stretching. There was no significant difference to maximum peak torque values of knee extensors (p=0.071). It can be understood that the active warm-up with static stretching before the maximum strength test on the isokinetic (60°/s) promotes an increasing on peak torque values of knee extensors and flexors as much as in the average values as in the maximum ones, in absolute terms, although the maximum peak torque of the extensors have not exhibited significant differences. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
17. Using an air cycle heat pump system with a turbocharger to supply heating for full electric vehicles.
- Author
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Li, Shuangshuang, Wang, Shugang, Ma, Zhenjun, Jiang, Shuang, and Zhang, Tengfei
- Subjects
- *
HEAT pumps , *AIR cycles (Mechanical engineering) , *TURBOCHARGERS , *ELECTRIC vehicles , *HEAT exchangers - Abstract
Air cycle heat pump has large potentials in heating applications. However, a key challenge faced nowadays is the matching problem between its expander and compressor. This paper presents the performance evaluation of an air cycle heat pump system integrated with a turbocharger, a blower and a regenerated heat exchanger. A thermodynamic model for this system is first developed and the relationships between the system performance and the operating parameters are investigated. Then, the performance of three different air cycle heat pumps with a blower installed before the compressor, and a blower installed before the turbine, and with an expander, are numerically simulated. The results indicated that the blower installed before the compressor can achieve a higher heating capacity and thus a higher COP. Finally, the heating power consumption of air cycle heat pump was compared with the PTC and the vapor compression heat pump of the full electric vehicle. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
18. Effects of microwave vs. convection oven heating on the formation of oxidation products in canola (Brassica rapa subsp. oleifera) oil.
- Author
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Suomela, Jukka-Pekka, Tarvainen, Marko, and Kallio, Heikki
- Subjects
- *
CONVECTION oven cooking , *MICROWAVE heating , *CANOLA oil , *OXIDATION , *OMEGA-3 fatty acids , *LIQUID chromatography-mass spectrometry - Abstract
Research on the effects of microwave vs. "conventional" heating of dietary oils on lipid oxidation has been very limited. In this study, canola oil (Brassica rapa subsp. oleifera) was heated in either convection or microwave oven to compare the effects of heating methods on triacylglycerol (TAG) oxidation. Peroxide and ρ-anisidine values (PV and ρ-AV, respectively) were determined and liquid chromatography-mass spectrometric (LC-MS) analysis of non-oxidized and oxidized TAG molecular species was performed. Neither of the heat treatments caused any considerable changes in PV of the oil samples. However, increase in ρ-AV was observed. The change was higher in the oil heated in microwave oven, demonstrating a higher increase in the amount of secondary oxidation products. The changes were accompanied by a decrease in the polyunsaturated TAG molecular species ACN:DB (acyl carbon number: number of double bonds) 54:7 and 54:6, this change also being higher in the oil heated in microwave oven. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
19. The effects of orifice nozzle number and nozzle made of polyamide plastic and aluminum with different inlet pressures on heating and cooling performance of counter flow Ranque–Hılsch vortex tubes: An experimental investigation.
- Author
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Cebeci, Ismail, Kirmaci, Volkan, and Topcuoglu, Umit
- Subjects
- *
POLYAMIDE fibers , *POLYAMIDES , *INLETS , *VORTEX tubes , *MATHEMATICAL models - Abstract
In this paper, the effects of the orifice nozzle number and the inlet pressure on heating and cooling performance of a counter flow Ranque–Hilsch type vortex tube (RHVT) (L/D ration is 10) are investigated by using air and oxygen as a fluid via an experimental method. Five orifices with two, three, four, five and six nozzles are made from the polyamide plastic and aluminum. The object of this research is to observe thermal behavior of air and oxygen, which are passing through an RHVT. Using two different fluids for each one of the orifices (nozzle numbers), inlet pressure is varied between 150 kPa and 700 kPa by increasing 50 kPa for each step and comparison is made between these two fluids by holding the cold mass fraction constant at 0.36. We show that the temperature gradient between the cold and hot fluid decreases whenever the orifice nozzle number increases. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
20. Efficacité économique et effets distributifs de long-terme des politiques de rénovation énergétique des logements
- Author
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Louis-Gaëtan Giraudet, Cyril Bourgeois, Philippe Quirion, Centre International de Recherche sur l'Environnement et le Développement (CIRED), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-École des Ponts ParisTech (ENPC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,Political science ,space heating ,energy-economy modelling ,fuel poverty ,energy efficiency subsidies ,carbon tax ,home energy retrofits ,Forestry ,010501 environmental sciences ,Business and International Management ,[SHS.ECO]Humanities and Social Sciences/Economics and Finance ,01 natural sciences ,7. Clean energy ,General Economics, Econometrics and Finance ,rénovation énergétique ,taxe carbone ,subventions à l’efficacité énergétique ,précarité énergétique ,évaluation intégrée ,chauffage ,0105 earth and related environmental sciences - Abstract
Using the Res-IRF energy-economy model, we evaluate the impact of four key energy efficiency subsidy programmes and the carbon tax on energy demand for residential heating in France. The carbon tax is found to be the most effective, yet also most regressive, instrument. Subsidies have a leverage effect of 1 to 1.4 in 2015. Targeting subsidies towards low-income households, that tend to live in energy inefficient dwellings, increases leverage, thus reconciling economic efficiency and social equity. Meeting the long-term energy saving targets set by the French government will require maintaining subsidy programmes until 2050 and extending them to rented dwellings., Nous évaluons, à l’aide du modèle technico-économique Res-IRF, l’effet des quatre principaux dispositifs de subvention à l’efficacité énergétique et de la taxe carbone sur la demande d’énergie pour le chauffage des logements en France. La taxe carbone s’avère être l’instrument le plus efficace, mais également le plus régressif. Les subventions induisent un effet de levier sur l’investissement de 1 à 1,4 en 2015. Le ciblage des subventions sur les ménages à bas revenus, qui sont surreprésentés dans les logements les moins performants, accroît l’effet de levier, permettant ainsi de concilier efficacité économique et équité sociale. L’atteinte des objectifs nationaux d’économie d’énergie nécessite de maintenir les subventions jusqu’en 2050 et de les étendre au parc locatif privé., Giraudet Louis-Gaëtan, Bourgeois Cyril, Quirion Philippe. Efficacité économique et effets distributifs de long-terme des politiques de rénovation énergétique des logements. In: Économie & prévision, n°217, 2020. pp. 43-63.
- Published
- 2020
21. Slowheat@LOCI
- Author
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Van Moeseke, Geoffrey and UCL - SST/LAB - Louvain research institute for Landscape, Architecture, Built environment
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Bâtiment ,IEQ ,Chauffage ,slowheat ,Chaleur ,Confort - Abstract
Slowheat@LOCI est une expérience visant à mesurer l’impact sur le confort et les consommations d’énergie de modifications des « usages thermiques ». Elle s’est déroulée sur le site de Saint-Gilles de la Faculté d’Architecture, d’Ingénierie Architecturale, d’Urbanisme (LOCI) de l’UCLouvain, en février et mars 2022. L’objectif de cette expérience est de démontrer qu’il est possible de maintenir la satisfaction des occupants tout en réalisant d’importantes économies d’énergie, grâce à une réflexion sur les conditions d’ambiance offertes par le bâtiment. En particulier, dans notre cas, il s’agit de sortir de l’uniformité des températures (globalement, tout le bâtiment est chauffé de la même façon), pour trouver une meilleur correspondance entre ambiances, espaces et usages. Le présent rapport conclut la première phase de l’expérience, et formule des recommandations portant sur la gestion thermique de ce bâtiment particulier, la définition d’expériences complémentaires, et la généralisations de pistes d’intervention sur d’autres sites de l’UCLouvain.
- Published
- 2022
22. Étude expérimentale et numérique de l'électro-migration du carbone dans le fer lors de la transformation de phase ferrite - austénite
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Monzey, Maxime and STAR, ABES
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Traitement thermique ,Electromigration ,Electric Current ,Matériaux ,Carbon diffusion ,Ferrite ,[SPI.MAT] Engineering Sciences [physics]/Materials ,Phase transformation ,Austenite ,Heating ,Steel industry ,Sidérurgie ,Thermal treatment ,Effet Joule ,Courant électrique ,Diffusion du carbone ,Chauffage ,Joule effect ,Transformation de phase ,Materials ,Austénite résiduelle - Abstract
Joule heating is widely used during the different thermal treatments and material forming processes in metallurgy. Until recently, thermal treatments assisted by electric current were considered equivalent to conventional heating methods. However, the evolution of the microstructure in presence of electric current is still not well understood. The aim of this thesis was to determine the impact of an electric current on the diffusion of carbon in iron and on the ferrite-to-austenite phase transformation. To study these phenomena, solid carburization of high-purity iron samples (ARMCO) is performed during thermal treatments in the intercritical domain. Samples are heated thanks to Joule effect induced by direct continuous or pulsed electric current. A model of carbon diffusion which accounts for both the phase transformation and the electromigration of carbon in iron has been proposed. The sensitivity study on the model parameters showed that the phase transformation kinetics mainly depends on the diffusion coefficient of carbon in austenite. In addition, the effective charge of carbon in austenite can be adjusted to model the electromigration of carbon. Thus, these two parameters were determined based on a comparison between experimental data and simulations. Phase transformation kinetics were found faster in the direction of the electric current and hindered in the opposite. A 30% higher current density resulted in a diffusion coefficient 50% higher. The effective charge was found to be between +12 and +36, depending on the experimental conditions. All these results are discussed in the light of the physical phenomena reported in the literature. In particular, they question the studies of the effective charge that do not consider the influence of current on the diffusion coefficient. This PhD-work also provides new values for the effective charge of carbon in the intercritical domain., Le chauffage par effet Joule est largement utilisé en métallurgie lors des différents traitements thermiques et procédés de mise en forme des matériaux. Ces traitements thermiques assistés par le courant électrique étaient, encore récemment, considérés comme équivalents aux méthodes de chauffage conventionnelles. Cependant, l'évolution de la microstructure en présence de courant électrique n'est pas encore bien comprise. L'objectif de cette thèse était de déterminer l'impact d'un courant électrique sur la diffusion du carbone dans le fer et sur la transformation de phase ferrite-austénite. Pour étudier ces phénomènes, la carburation solide d'échantillons de fer de haute pureté (ARMCO) est réalisée lors de traitements thermiques dans le domaine intercritique. Les échantillons sont chauffés grâce à l'effet Joule induit par un courant électrique direct continu ou pulsé. Un modèle de diffusion du carbone qui tient compte à la fois de la transformation de phase et de l'électro-migration du carbone dans le fer a été proposé. L'étude de sensibilité des paramètres du modèle a démontré que la cinétique de transformation de phase dépend principalement du coefficient de diffusion du carbone dans l'austénite. En outre, la charge effective du carbone dans l'austénite peut être ajustée pour modéliser l'électro-migration du carbone. Ainsi, ces deux paramètres ont été déterminés sur la base d'une comparaison entre les données expérimentales et les simulations. La cinétique de transformation de phase s'est avérée plus rapide dans le sens du courant électrique et freinée dans le sens inverse. Une densité de courant supérieure de 30 % a entraîné un coefficient de diffusion supérieur de 50 %. La charge effective se situe entre +12 et +36, selon les conditions expérimentales. Tous ces résultats sont discutés à la lumière des phénomènes physiques rapportés dans la littérature. En particulier, ils remettent en cause les études de la charge effective qui ne prennent pas en compte l'influence du courant sur le coefficient de diffusion. Ce travail de thèse fournit également de nouvelles valeurs pour la charge effective du carbone dans le domaine intercritique.
- Published
- 2022
23. Caractérisation des modèles types de chaînes de valeur de la biomasse forestière.
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LOCOH, AYAOVI, THIFFAULT, ÉVELYNE, BARNABÉ, SIMON, and BOUTHILLIER, LUC
- Abstract
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- Published
- 2022
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24. Conformational change in individual enzyme molecules.
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Crawford, Jeremie J., Itzkow, Frannie, MacLean, Joanna, and Craig, Douglas B.
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- *
GALACTOSIDASES , *CAPILLARY electrophoresis , *FLUORESCENCE , *HEAT shock proteins , *PROTEIN expression - Abstract
Single β-galactosidase molecule assays were performed using a capillary electrophoresis based protocol, employing post-column laser-induced fluorescence detection. In a first set of experiments, the distribution of single β-galactosidase molecule catalytic rates and electrophoretic mobilities were determined from lysates of Escherichia coli strains containing deletions for different heat shock proteins and grown under normal and heat shock conditions. There was no clear observed pattern of effect of heat shock protein expression on these distributions. In a second set of experiments, individual enzyme molecule catalytic rates were determined at 21 °C before and after 2 sequential brief periods of incubation at 50, 28, and 10 °C. The brief incubations at 50 °C caused a change in the enzyme molecules resulting in a different catalytic rate. Any given molecule was just as likely to show an increase in rate as a decrease, resulting in no significant difference in the average rate of the population. The average change in individual molecule rate was dependent upon the temperature of the brief incubation period, with a lesser average change occurring at 28 °C and negligible change at 10 °C. A third set of experiments was similar to that of the second with the exception that it was electrophoretic mobility that was considered. This provided a similar result. Incubation at higher temperature resulted in a change in electrophoretic mobility. The probability of an individual molecules switching to a higher mobility was approximately equal to that of switching to a lower mobility, resulting in no net average change in the population. The magnitude of the changes in electrophoretic mobilities suggest that the associated conformational changes are subtle. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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25. Analysis and prediction of chilled water plant performance based on multivariate statistical methods and large historical data
- Author
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Beaulieu St-Laurent, Philip, Gosselin, Louis, Duchesne, Carl, Beaulieu St-Laurent, Philip, Gosselin, Louis, and Duchesne, Carl
- Abstract
The large datasets resulting from operating HVAC&R systems are currently scrutinized to find ways to exploit the useful information that they might contain. In this work, historical data of a centrifugal water chiller over the course of more than 1.5 years of operation is used to learn about the system and to suggest modifications to its operation scheme. The results show that principal component analysis (PCA) captures well the variance in the historical data. The first two principal components explained between 62 and 80% of the variance, depending on the cases considered. The main factors responsible for the variation of the chiller operation are found to be the weather and the cold water temperature setpoint. The effect of the sampling time step on the results is also studied. Moreover, this work demonstrates that partial least squares (PLS) regression can adequately predict an important indicator of the chiller performance, namely the coefficient of performance (COP), one time step ahead with an R² of 77.49% and root-mean square error of estimation (RMSEE) of 0.463 using a separate validation set of data. The PLS model was also able to predict future COP values up to 2 time steps (∼3 h) in advance.
- Published
- 2021
26. Normes de chauffe et transition énergétique : les transactions des habitants
- Author
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Yankel Fijalkow, Bruno Maresca, Fijalkow, Yankel, Centre de Recherche sur l'Habitat (CRH), Laboratoire Architecture, Ville, Urbanisme, Environnement (LAVUE), Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)-Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), and Centre de recherche pour l'étude et l'observation des conditions de vie (CREDOC)
- Subjects
0507 social and economic geography ,habitat ,chauffage ,heating ,010501 environmental sciences ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,lcsh:Social Sciences ,lcsh:Science ,housing ,technologies ,0105 earth and related environmental sciences ,General Environmental Science ,[SHS.ARCHI]Humanities and Social Sciences/Architecture, space management ,transition énergétique ,05 social sciences ,General Social Sciences ,environnement ,lcsh:H ,energy transition ,technology ,General Earth and Planetary Sciences ,lcsh:Q ,[SHS.ARCHI] Humanities and Social Sciences/Architecture, space management ,General Agricultural and Biological Sciences ,050703 geography - Abstract
Heating standards and energy transition; an investigation on the transactions of home dwellers. The debate about the notion of energy transition questions the lack of consideration by public authorities of the discrepancy between household heating practices and the rules put forward by these same authorities. This paper describes the main results of recent surveys and proposes to highlight them by examining the evolution of comfort standards in housing and the way they are produced. Mobilizing the social transaction theory enabled us to reveal the difficulty for housing policies to develop shared positions. We showed that household practices, which result in house heating temperatures actually higher than the 19 degrees norm, form a real critique of the energy transition theory. In being unable to have the norm accepted in household behavior despite the urgency of controlling the demand for energy, the energy transition theory proves to be unrealistic in overlooking the mechanisms of social practice., On interroge dans cet article la notion de transition énergétique en explorant la non-prise en compte par les pouvoirs publics de l'écart entre les pratiques de chauffage des ménages et les dispositifs d'injonctions mis en oeuvre. Après avoir discuté les résultats d'enquêtes récentes sur les températures de chauffe des ménages, on revisite l'évolution et le mode de production des normes de confort dans l'habitat et on analyse les pratiques de chauffage à l'aune de la notion de transaction sociale. Les pratiques des ménages, qui conduisent à des températures réelles de chauffe des habitations plus élevées que les 19 degrés de la norme, constituent une critique de fait de la transition énergétique. Ne parvenant pas à « faire passer la norme » dans les comportements en dépit des urgences de la maîtrise de la demande en énergie, la transition énergétique se révèle velléitaire par ignorance des mécanismes de la pratique sociale.
- Published
- 2019
27. A theoretical study on a novel solar based integrated system for simultaneous production of cooling and heating.
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Khaliq, Abdul
- Subjects
- *
SOLAR energy , *THERMODYNAMICS , *ENERGY consumption , *TEMPERATURE measurements , *HELIOSTATS - Abstract
An integrated system for simultaneous production of triple-effect cooling and single stage heating is proposed in this paper to harness low grade solar energy. The proposed system combines the heliostat field with a central receiver and the ejector-absorption cycle with the shaft power driven transcritical CO 2 cycle. A parametric study based on first and second laws of thermodynamics is carried out to ascertain the effect of varying the exit temperature of duratherm oil, turbine inlet pressure, and evaporators temperature on the energy and exergy output as well as on the energy and exergy efficiencies of the system. The results obtained indicate that major source of exergy destruction is the central receiver where 52.5% of the inlet solar heat exergy is lost followed by the heliostat where 25% of the inlet exergy is destroyed. The energy and exergy efficiencies of the integrated system vary from 32% to 39% and 2.5%–4.0%, respectively, with a rise in the hot oil outlet temperature from 160 °C–180 °C. It is further shown that increase in evaporator temperature of transcritical CO 2 cycle from −20 °C to 0 °C increases the energy efficiency from 27.45% to 43.27% and exergy efficiency from 2.51% to 2.97%, respectively. The results clearly show how the variation in the values of hot oil outlet temperature, turbine inlet pressure, and the evaporator temperature of transcritical CO2 cycle strongly influences the attainable performance of the integrated system. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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- View/download PDF
28. A comparison of antioxidant activities by eugenyl acetate and eugenyl butyrate at frying temperature
- Author
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Seyed Mohammad Hashem Hosseini, Pierre Villeneuve, Malihe Keramat, Mohammad-Taghi Golmakani, and Erwann Durand
- Subjects
0106 biological sciences ,Antioxidant ,food.ingredient ,General Chemical Engineering ,medicine.medical_treatment ,Butyrate ,01 natural sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,food ,Q02 - Traitement et conservation des produits alimentaires ,010608 biotechnology ,medicine ,Food science ,Autocatalytic reaction ,Canola ,Q04 - Composition des produits alimentaires ,Acétate ,Chemistry ,04 agricultural and veterinary sciences ,General Chemistry ,Limiting ,Cuisson micro-ondes ,040401 food science ,Antioxydant ,Eugénol ,Eugenol ,Antioxidant capacity ,Composé phénolique ,Huile essentielle ,Eugenyl acetate ,Chauffage ,Huile de colza ,Food Science - Abstract
The objective of this study was to compare the antioxidant capacities of eugenyl acetate, eugenyl butyrate, eugenol/eugenyl acetate combinations, and eugenol/eugenyl butyrate combinations in canola oil at frying temperature (180°C). Eugenol and a synthetic antioxidant (BHT) were considered as reference in terms of antioxidant capacity. Eugenyl acetate and eugenyl butyrate were produced by autocatalytic reactions through microwave heating. Eugenyl acetate was more effective than eugenol and eugenyl butyrate in reducing the anisidine value and total polar compounds in canola oil during heating at frying temperature. In addition, the combinations of eugenol/eugenyl acetate (50/50%, wt/wt) and eugenol/eugenyl butyrate (25/75, 50/50, and 75/25%, wt/wt) were more effective than each of the antioxidants alone in reducing the oxidation of canola oil. More time was required to achieve the upper legal limit of total polar compounds in canola oil when different antioxidant compounds were added to the oil. Practical applications: Eugenol, the major compound in several important essential oils is known to have strong antioxidant activity. However, the exposure of eugenol to high temperatures makes it chemically instable, thereby limiting its applications in food industry. Modifying the structure of phenolic compounds via esterification can be used as an effective method to maintain it effectiveness at high temperature. Hence, this study was designed to evaluate the thermal stability of eugenol, eugenyl acetate, eugenyl butyrate, and combinations of eugenol/eugenyl acetate and eugenol/eugenyl butyrate during heating at frying temperature.
- Published
- 2021
29. Study of multi-function absorption heat pumps for heating network substations
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Chardon, Gaétan, Le Pierrès, Nolwenn, Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont blanc, Nolwenn LE PIERRES, and Julien RAMOUSSE
- Subjects
modèle numérique dynamique ,4th generation district heating network ,heat upgrading ,[SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering ,experimental prototype ,chauffage ,air conditioning ,heating ,revalorisation thermique ,[SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph] ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,Réseau de chaleur 4ème génération ,dynamic numerical model ,climatisation ,prototype expérimental ,[SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph] - Abstract
This work studies the opportunity to integrate absorption heat pumps (AHP) in substations of district heating networks (DHN). The challenge is to improve the energy efficiency of DHN and to allow better integration of renewable energies. Three AHP operating modes are possible to satisfy the needs of buildings throughout the year by using DHN heat, by : (i) locally increasing the available temperature of the DHN to satisfy the high-temperature heating needs of buildings, for example from a lowtemperature DHN; (ii) air conditioning of the buildings from the heat of the DHN, for example in summer; (iii) improving the heat transfer between the DHN and the building. To compare the performances reached with several absorbent-refrigerant pairs, a steady-state model was developed. The model simulates the AHP under typical operating conditions of DHN substations for the three considered operating modes. According to the model, the NH3-LiNO3 pair was identified as the most relevant one. Then, a dynamic model was developed to simulate the system under varying operating conditions. An experimental prototype with 3 kW cooling capacity was dimensioned, built and tested with the NH3-LiNO3 couple, to validate the feasibility of the concept, quantify its performance and validate the numerical model.Following this validation, the model was used to study the relevance of the use of AHP in DHN substations to satisfy the heating and cooling needs, improve the DHN performances and promote integration of new low temperature renewable energy sources., Ce travail de thèse étudie l’opportunité d’intégrer des pompes à chaleur à absorption (PàCs) dans les sous-stations des réseaux de chauffage (RdC). L’enjeu est de contribuer à la meilleure efficacité énergétique des RdC et d’y permettre une meilleure intégration des énergies renouvelables. Trois modes de fonctionnement de la PàCs sont proposés pour répondre aux besoins des bâtiments tout au long de l’année à partir de la chaleur du RdC, en :— augmentant localement la température disponible du RdC pour couvrir les besoins de chaleur à haute température des bâtiments, à partir d’un RdC à basse température par exemple ;— rafraichissant les bâtiments à partir de la chaleur du RdC, en été par exemple ;— améliorant le transfert de chaleur entre le RdC et le bâtiment.Pour comparer les performances atteintes avec plusieurs couples absorbant-réfrigérant, un modèle en régime permanent a été développé pour simuler la PàCs dans des conditions de fonctionnement typiques des sous-stations de RdC, pour les trois modes de fonctionnement considérés. Ce modèle a permis d’identifier le couple NH3-LiNO3 comme couple le plus pertinent. Puis, un modèle dynamique a été développé pour simuler le système lors de variations de conditions de fonctionnement.Un prototype expérimental d’une puissance froid de 3 kW, utilisant le couple NH3-LiNO3, a été dimensionné, construit et testé pour valider la faisabilité du concept, quantifier ses performances et valider le modèle numérique. Suite à cette validation, le modèle a été utilisé pour étudier la pertinence de l’utilisation de PàCs en sous-station de RdC pour répondre aux besoins de chaleur et de froid des bâtiments et ainsi améliorer les performances du RdC et favoriser l’intégration de nouvelles sources d’énergie renouvelable à basse température.
- Published
- 2021
30. Précarité énergétique:10 ans plus tard, une notion toujours floue
- Author
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Sébert, A. (Adèle), Université de Lille, CNRS, Univ. Littoral Côte d’Opale, and Centre Lillois d’Études et de Recherches Sociologiques et Économiques - UMR 8019 [CLERSÉ]
- Subjects
énergie ,pauvreté ,électricité ,précarité ,chauffage ,précarité énergétique ,mal-logement - Published
- 2020
31. Peut-on éviter des émissions de CO2 en pilotant l'appoint gaz de pompes à chaleur hybrides ?
- Author
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Marianne Biéron, Jérôme Le Dréau, Benjamin Haas, Laboratoire des Sciences de l'Ingénieur pour l'Environnement - UMR 7356 (LaSIE), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), ENGIE, and Le Dréau, Jérôme
- Subjects
[SPI.GCIV.CD]Engineering Sciences [physics]/Civil Engineering/Construction durable ,Electrical system model ,listes de priorité ,Modélisation du système électrique ,chauffage ,[SPI.GCIV.CD] Engineering Sciences [physics]/Civil Engineering/Construction durable ,marginal emission factor ,chauffage Electrical system model ,space heating ,priority list ,facteur d'émission marginal - Abstract
International audience; Le chauffage dans le secteur résidentiel représente environ 20% de la consommation énergétique française. Cet usage étant à la fois réparti sur différents vecteurs énergétiques et très saisonnalisé, choisir le bon vecteur au bon moment est un moyen efficace de le décarboner. La gestion de la demande énergétique des bâtiments est de plus un levier pour l'intégration des énergies renouvelables non pilotables dans les mix électriques et pour l'effacement des appels de puissance lorsque les moyens marginaux de production sont carbonés. Cet article s'intéresse au pilotage de pompes à chaleur hybrides alimentées par le réseau électrique et un appoint gaz local de manière à minimiser les émissions de GES. Pour ce faire, il est nécessaire de déterminer le contenu carbone de la consommation d'électricité évitée durant tout le temps de fonctionnement de l'appoint gaz. L'objectif de cet article est d'estimer le type de pilotage (fréquence et durée de l'utilisation de l'appoint gaz) de ces systèmes. A terme, la détermination de l'impact en ACV du déploiement de telles technologies sur les émissions de GES sera nécessaire.
- Published
- 2020
32. Study of wave propagation in various kinds of plasmas using adapted simulation methods, with illustrations on possible future applications.
- Author
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Heuraux, Stéphane, Faudot, Éric, da Silva, Filipe, Jacquot, Jonathan, Colas, Laurent, Hacquin, Sébastien, Teplova, Natalia, Syseova, Kate, and Gusakov, Evgeniy
- Subjects
- *
THEORY of wave motion , *COMPUTER simulation , *MAGNETIZATION , *BOUNDARY value problems , *NUMERICAL analysis , *MATCHING theory , *ELECTROMAGNETIC waves - Abstract
Abstract: The understanding of wave propagation in turbulent magnetized plasmas can be rather complex, particularly if they are inhomogeneous and time-dependent. Simulation can be a useful tool for wave propagation studies, provided that the “model” equations take into account the characteristics of the medium relevant for the studied problem and that the numerical scheme including boundary conditions is stable and accurate enough. The choices for the model equations and the corresponding schemes are analyzed and discussed as a function of various parameters, such as the order of the numerical scheme and the number of grid points per wavelength. A quick review of the up-to-date numerical developments is given on the sheath boundary conditions and on the perfect matching layer in anisotropic media. Possible developments of plasma diagnostics conclude this state-of-the-art of simulations of electromagnetic waves in plasmas. [Copyright &y& Elsevier]
- Published
- 2014
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- View/download PDF
33. AVIS relatif à l’utilisation des appareils de chauffage dans le contexte de l’épidémie de Covid-19 (HCSP, Avis et Rapports)
- Author
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Camus, Daniel, Chidiac, Christian, Gehanno, Jean-François, Aho-Glélé, Serge, Lepelletier, Didier, Brignon, Jean-Marc, Hartemann, Philippe, Levi, Yves, Marano, Francelyne, Roubaty, Jean-Louis, Squinazi, Fabien, Berger-Carbonne, Anne, Eterradossi, Nicolas, Salvat, Gilles, Gaffet, Éric, PAVAGEAU, Yannick, Commission Spécialisée Maladies infectieuses et maladies émergentes (CSMime), Haut Conseil de la Santé Publique (HCSP), Commission Spécialisée Système de santé et sécurité des patients (CS3SP), Commission Spécialisée Risques liés à l’environnement (CSRE), Santé publique France - French National Public Health Agency [Saint-Maurice, France], Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Haut Conseil de la Santé Publique
- Subjects
Prévention ,Maladies transmissibles ,SARS-CoV-2 ,Lieu travail ,Environnement ,Coronavirus ,Lieux publics ,Lieu à usage collectif ,Bâtiment ,Aérosol ,Confort thermique ,[SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie ,Chauffage ,Covid-19 - Abstract
International audience; Quels sont les messages à retenir en matière de chauffage des locaux et de préparation hivernale des bâtiments dans le contexte de l’épidémie de Covid-19 ?Dans un avis du 14 octobre 2020, le HCSP recommande de maintenir le chauffage des espaces clos collectifs, afin d’atteindre une température de confort en adéquation avec l’activité des occupants. Il convient par ailleurs d’assurer le renouvellement régulier de l’air des locaux avec un apport d’air neuf qui devra, si possible, être augmenté.La mesure en continu de la concentration en dioxyde de carbone (CO2), à l’aide de capteurs, permet d’en juger la qualité.Le HCSP recommande de limiter strictement la jauge d’occupation à ce que permet le débit réel d’air neuf entrant dans le local tout en respectant la distanciation physique. Il propose que les appareils de chauffage à air pulsé et les systèmes de ventilation mécanique soient maintenus en fonctionnement continu. Le HCSP recommande de vérifier l’absence d’obstacles au bon fonctionnement de la diffusion de l’air dans les locaux, et d’éviter le recyclage d’air par l’installation centralisée de traitement d’air pour éviter le transfert éventuel d’aérosols viraux dans plusieurs locaux.Le HCSP souligne la nécessité d’ouvrir les fenêtres pendant quelques minutes, plusieurs fois par jour, afin d’augmenter encore le niveau de renouvellement d’air dans les locaux. Il rappelle qu’une hygrométrie trop basse favorise la formation d’aérosols.
- Published
- 2020
34. Heating standards and energy transition; an investigation on the transactions of home dwellers
- Author
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Fijalkow, Yankel, Maresca, Bruno, Centre de Recherche sur l'Habitat (CRH), Laboratoire Architecture, Ville, Urbanisme, Environnement (LAVUE), Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)-Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Centre de recherche pour l'étude et l'observation des conditions de vie (CREDOC), Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)-Université Paris 8 Vincennes-Saint-Denis (UP8)-École nationale supérieure d'architecture de Paris-La Villette (ENSAPLV), and HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris Nanterre (UPN)-École nationale supérieure d'architecture de Paris Val-de-Seine (ENSA PVDS)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC)
- Subjects
[SHS.ARCHI]Humanities and Social Sciences/Architecture, space management ,energy transition ,transition énergétique ,technology ,habitat ,chauffage ,heating ,housing ,environnement ,technologies - Abstract
International audience; Heating standards and energy transition; an investigation on the transactions of home dwellers. The debate about the notion of energy transition questions the lack of consideration by public authorities of the discrepancy between household heating practices and the rules put forward by these same authorities. This paper describes the main results of recent surveys and proposes to highlight them by examining the evolution of comfort standards in housing and the way they are produced. Mobilizing the social transaction theory enabled us to reveal the difficulty for housing policies to develop shared positions. We showed that household practices, which result in house heating temperatures actually higher than the 19 degrees norm, form a real critique of the energy transition theory. In being unable to have the norm accepted in household behavior despite the urgency of controlling the demand for energy, the energy transition theory proves to be unrealistic in overlooking the mechanisms of social practice.; On interroge dans cet article la notion de transition énergétique en explorant la non-prise en compte par les pouvoirs publics de l'écart entre les pratiques de chauffage des ménages et les dispositifs d'injonctions mis en oeuvre. Après avoir discuté les résultats d'enquêtes récentes sur les températures de chauffe des ménages, on revisite l'évolution et le mode de production des normes de confort dans l'habitat et on analyse les pratiques de chauffage à l'aune de la notion de transaction sociale. Les pratiques des ménages, qui conduisent à des températures réelles de chauffe des habitations plus élevées que les 19 degrés de la norme, constituent une critique de fait de la transition énergétique. Ne parvenant pas à « faire passer la norme » dans les comportements en dépit des urgences de la maîtrise de la demande en énergie, la transition énergétique se révèle velléitaire par ignorance des mécanismes de la pratique sociale.
- Published
- 2020
35. Study of the comfort and management of a heterogeneous set of devices for the collection, storage and distribution of renewable energy for individual homes
- Author
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Aboïna, Gérard Tchakblo, Centre d'Etudes et Recherches en Thermique, Environnement et Systèmes [Créteil] (CERTES EA 3481), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Université Paris-Est, Institut National Supérieur du Sahara et du Sahel d'Iriba, Gilles Lefebvre, Mahamadou Abdou Tankari, and STAR, ABES
- Subjects
Optimization ,[SPI.OTHER]Engineering Sciences [physics]/Other ,[SPI.OTHER] Engineering Sciences [physics]/Other ,Renewable energies ,Energies renouvelable ,Comfort ,Management ,Heating ,Gestion ,Batiment ,Building ,Optimisation ,Chauffage ,Confort - Abstract
Our days, the energy and environmental challenges facing humanity are accentuated by global population growth. Thereby, we are witnessing inexorably the exhaustion of energy resources with climatic consequences. Scientific studies show that the building sector in the world is one of the largest consumers of energy, with a percentage between 40% and 50% of annual consumption. In order to reduce this energetic chasm that constitutes the building with all its corollaries that are air pollution, global warming and others. Several standards governing the construction of buildings have been put in place in France, the last of which is RT2012. It aims to accompany designers to build modern buildings that guarantee thermal comfort and reduce energy consumption. And so, the ultimate goal of this thermal regulation is to achieve not only low-energy buildings but zero energy buildings by 2050, incorporating renewable solar photovoltaic and thermal equipment.It is in this perspective that our thesis topic has been written, the objective of which is to develop tools and techniques allowing the choice of equipment suitable for solar heating of building on one hand, to manage these renewable solar resources of somewhere else. Thus, thermo-electric systems coupled by a heat pump studied in our work, leads us to structure our dissertation in two major parts : thermal and electrical. In the first part, we talked about designing a decision support tool. The design of the tool results from the analysis of the parameters influencing the energy performance of the building. Bibliographic research has led to the development and selection of relevant models of the components of the thermal heating system. The aggregation and implementation of the models in the Matlab/Simulink environment made this sizing tool possible. Its multi-criteria optimization approach is based on a statistical approach whose "objective" functions are correlated with thermal comfort and electrical energy consumption. A method of analysis of the results put in place made it possible to find several optimal solutions of which only one is retained.The second part of the thesis deals with the development of a management algorithm to supervise and control a multi-source energy system including photovoltaic and wind turbine with storage unit, batteries. It is an intelligent algorithm based on fuzzy logic including input variables consisting of photovoltaic power, wind power, battery charge status and load profile. It is used in the study case to the solicitations of the heat pump serving as interface of the heating system of the building, De nos jours, les enjeux énergétiques et environnementaux auxquels fait face l’humanité, sont accentués par la croissance démographique mondiale. A cet effet, on assiste inexorablement à l’épuisement des ressources énergétiques assorties des conséquences climatiques. Il ressort des études scientifiques que, dans le monde, le secteur de bâtiment est l’un des plus gros consommateurs d’énergie, avec un pourcentage situé entre 40 à 50% de la consommation annuelle. Afin de réduire ce gouffre énergetique que constitue le bâtiment avec tous ses corollaires que sont la pollution atmosphérique, le réchauffement climatique et autres, plusieurs normes régissant la construction des bâtiments ont été mise en place en France dont la dernière est la RT2012. Elle vise à accompagner les concepteurs à réaliser des bâtiments modernes garantissant le confort thermique et moins énergivores. Et donc, l’objectif final de cette règlementation thermique est de réaliser non seulement des bâtiments basse consommation mais des bâtiments zéro énergie à l’horizon 2050, intégrant du matériel solaire photovoltaïque et thermique renouvelable.C’est dans cette optique que s’est inscrit notre sujet de thèse dont l’objectif est de développer des outils et techniques permettant de choisir des équipements appropriés au chauffage solaire de bâtiment d’une part, de gérer ces ressources solaires renouvelables d’autre part. Ainsi, les systèmes thermo-electriques couplés par une pompe à chaleur étudiés dans nos travaux, nous amène à structurer notre mémoire de thèse en deux grandes parties : thermique et électrique.Dans la première partie, il a été question de la conception d’un outil d’aide aux décisions. La conception de l’outil résulte de l’analyse des paramètres influençant la performance énergetique du bâtiment. Des recherches bibliographiques ont permis de développer et choisir des modèles pertinents des composants du système thermique de chauffage. L’agrégation et l’implémentation des modèles dans l’environnement Matlab/Simulink ont permis de réaliser cet outil de dimensionnement. La démarche d’optimisation multicritère de ce dernier est basée sur une approche statistique dont les fonctions « objectif » sont en corrélation avec le confort thermique et la consommation d’énergie électrique. Une méthode d’analyse des résultats mise en place a permis de trouver plusieurs solutions optimales dont une seule est retenue.La seconde partie de la thèse traite du développement d’un algorithme de gestion visant à superviser et commander un système multi-sources d’énergies comprenant le photovoltaïque et l’éolien avec unité de stockage, batteries. C’est un algorithme intelligent réalisé à partir de la logique floue dont les variables d’entrées constituées de la puissance photovoltaïque, la puissance éolienne, l’état de charge des batteries et le profil de sollicitation de charges. Il est utilisé dans le cas d’étude aux sollicitations de la pompe à chaleur servant d’interface du système de chauffage du bâtiment
- Published
- 2020
36. Quebec Construction Code, Chapter I.1 – Energy Efficiency of Buildings, and National Energy Code of Canada for Buildings 2015 (amended)
- Author
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Canadian Commission on Building and Fire Codes and Natural Resources Canada
- Subjects
Codes & guides ,ventilation ,Quebec ,chauffage ,heating ,air conditioning ,bâtiment ,Codes et guides ,Québec ,CNRCCode ,building ,NRCCode ,energy ,énergie ,conditionnement d’air - Abstract
The Régie du bâtiment du Québec and the National Research Council of Canada present the Quebec Construction Code, Chapter I.1 – Energy Efficiency of Buildings, and National Energy Code for Buildings 2015 (amended), which has been prepared to facilitate the application throughout the province of Quebec of the Construction Code adopted under the Building Act (O.C. 486-2020, 2020 G.O. 2, 1425)., On inside cover: First Edition 2020, For questions about Code licensing, sales, technical support, to obtain accessible copies, or to learn about other accommodations, please contact the NRC's Codes Canada team: (https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/help-using-accessing-codes/contact-codes-canada), Pour des questions relatives aux codes ou aux licences, aux ventes et au soutien technique qui s'y rapportent, pour l'obtention d'une copie accessible ou pour en savoir plus sur d'autres mesures d'adaptation, prière de communiquer avec l'équipe de Codes Canada au CNRC : (https://nrc.canada.ca/fr/certifications-evaluations-normes/codes-canada/aide-lutilisation-laccessibilite-codes/communiquer-codes-canada), For questions or comments about the content of the Codes and User’s Guides, please contact the CBHCC Secretary ., Veuillez adresser toute question ou tout commentaire au sujet du contenu des codes et des guides de l’utilisateur au Secrétaire du CCHCC .
- Published
- 2020
37. Code de construction du Québec, Chapitre I.1 – Efficacité énergétique du bâtiment, et Code national de l'énergie pour les bâtiments – Canada 2015 (modifié)
- Author
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Commission canadienne des codes du bâtiment et de prévention des incendies, Ressources naturelles Canada, and Régie du bâtiment du Québec
- Subjects
Codes & guides ,ventilation ,Quebec ,chauffage ,heating ,air conditioning ,bâtiment ,Codes et guides ,Québec ,CNRCCode ,building ,NRCCode ,energy ,énergie ,conditionnement d’air - Abstract
La Régie du bâtiment du Québec et le Conseil national de recherches du Canada vous présentent le Code de construction du Québec, Chapitre I.1 – Efficacité énergétique du bâtiment, et Code national de l’énergie pour les bâtiments – Canada 2015 (modifié). Ce document a été préparé afin de faciliter l’application du Code de construction adopté en vertu de la Loi sur le bâtiment (décret 486-2020, G.O. 2, 2161) sur l'ensemble du territoire du Québec., Sur la couverture intérieure : Première édition 2020, For questions about Code licensing, sales, technical support, to obtain accessible copies, or to learn about other accommodations, please contact the NRC's Codes Canada team: (https://nrc.canada.ca/en/certifications-evaluations-standards/codes-canada/help-using-accessing-codes/contact-codes-canada), Pour des questions relatives aux codes ou aux licences, aux ventes et au soutien technique qui s'y rapportent, pour l'obtention d'une copie accessible ou pour en savoir plus sur d'autres mesures d'adaptation, prière de communiquer avec l'équipe de Codes Canada au CNRC : (https://nrc.canada.ca/fr/certifications-evaluations-normes/codes-canada/aide-lutilisation-laccessibilite-codes/communiquer-codes-canada), For questions or comments about the content of the Codes and User’s Guides, please contact the CBHCC Secretary ., Veuillez adresser toute question ou tout commentaire au sujet du contenu des codes et des guides de l’utilisateur au Secrétaire du CCHCC .
- Published
- 2020
38. Effet à long terme de la poursuite sur les performances d’un système de chauffe eau solaire
- Author
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M. Koussa, M. Haddadi, and A. Malek
- Subjects
chauffage ,irradiation ,température ,Renewable energy sources ,TJ807-830 - Abstract
Ce travail consiste à développer un programme Matlab permettant de calculer à long terme les performances d’un système de chauffe eau solaire, et nécessitant que quelques paramètres météorologiques. Le programme est basé sur la méthode f-chart. Pour la validation du programme, nous avons retenu le site de Bouzaréah, où est installé le système de chauffage collectif. Les résultats obtenus par le programme Matlab développé ont été comparés avec ceux obtenus par le logiciel Simsol (CSTB). Ainsi, les résultats obtenus sont très satisfaisants.
- Published
- 2012
39. Confort thermique d’un local d’habitation: Simulation thermoaéraulique pour différents systèmes de chauffage
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F. Boudali Errebai, L. Derradji, Y. Maoudj, M. Amara, and A. Mokhtari
- Subjects
indices de confort thermique ,cfd ,ventilation ,chauffage ,Renewable energy sources ,TJ807-830 - Abstract
Le choix du mode de chauffage dans une habitation est un facteur important pour assurer le confort des habitants, ainsi que la réduction des besoins en chauffage, qui elle-même participe à la réduction des gaz à effet de serre. Nous présentons dans ce cadre, une étude qui consiste à faire des simulations numériques du comportement thermo-aéraulique des ambiances intérieures des locaux d’habitation, en utilisant un logiciel de mécanique des fluides. L’objectif principal de ce travail est l’évaluation du confort thermique dans le local en comparant les résultats numériques obtenus pour un local d’habitation chauffé par différents systèmes. Les résultats obtenus montrent que l’utilisation d’un système de chauffage par plancher chauffant dans un local d’habitation permet d’assurer un meilleur confort thermique.
- Published
- 2012
40. Etude et optimisation des installations energétiques d’un pôle universitaire
- Author
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Tavallo Pina, Uxue, Pinto Cámara, Charles Richard, Master de Ingeniería (Ind902), and Ingeniariako Master (Ind902)
- Subjects
programmation ,électricité ,plomberie ,automates ,préventif ,communication ,ventilation ,formulaires ,correctif ,chauffage ,Etablissement de Réception du Public (ERP) ,technique ,pôle universitaire ,Gestion de la Maintenance Assistée par Ordinateur (GMAO) ,consommations ,Immeuble Grande Hauteur (IGH) ,procédures ,PULV (Pôle Universitaire Léonard de Vinci ,Gestion Technique du Bâtiment (GTB) ,exploitation ,management ,climatisation - Abstract
Ce document constitue mon rapport de Stage de Fin d’Etudespour l’obtention du Diplôme d’Ingénieur à l’Ecole Nationale Supérieure des Arts et Métiers. Il a eu une durée de 6 mois et je l’ai réalisé au sein d’ENGIE Cofely, dans la Business Line «Sites d’Exception», dans le Département «Hôtellerie et Ministères». Au cours de ce stage j’ai participé en tant qu’Ingénieur Méthodes-Exploitation à la prise en charge d’un contrat de maintenance multi technique en CVC, plomberie et électricité dans le Pôle Universitaire Léonard de Vinci, situé à la Défense, Paris.
- Published
- 2019
41. Efficiency assessment of key psychometric processes
- Author
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Ratlamwala, T.A.H. and Dincer, I.
- Subjects
- *
EXERGY , *PSYCHOMETRICS , *ENERGY consumption , *HUMIDITY control , *TEMPERATURE effect , *ADIABATIC compression , *PARAMETER estimation - Abstract
Abstract: The study focuses on defining energy and exergy efficiencies based on three different types of approaches. For each of five key psychometric processes, such as heating or cooling, heating with humidification, cooling with dehumidification, evaporative cooling, and adiabatic mixing, parametric studies are carried out. Two efficiencies are newly proposed here in this study, and the third efficiency is taken from the literature for comparison purposes. The results show that for heating process exergy efficiency varies from 0.012 to 0.48 with rise in ambient temperature. Increasing ambient temperature results in variation of exergy efficiency from 0.014 to 0.29 for heating with humidification process. For cooling with dehumidification process exergy efficiency varies from 0.002 to 0.73 with rise in ambient temperature. The exergetic efficiency of evaporative cooling process varies from 0.64 to 0.03 with an increase in ambient temperature. For adiabatic mixing process, exergy efficiency varies from 0.65 to 0.94 with rise in ambient temperature. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
42. Etude et optimisation des installations energétiques d’un pôle universitaire
- Author
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Pinto Cámara, Charles Richard, Master de Ingeniería (Ind902), Ingeniariako Master (Ind902), Tavallo Pina, Uxue, Pinto Cámara, Charles Richard, Master de Ingeniería (Ind902), Ingeniariako Master (Ind902), and Tavallo Pina, Uxue
- Abstract
Ce document constitue mon rapport de Stage de Fin d’Etudespour l’obtention du Diplôme d’Ingénieur à l’Ecole Nationale Supérieure des Arts et Métiers. Il a eu une durée de 6 mois et je l’ai réalisé au sein d’ENGIE Cofely, dans la Business Line «Sites d’Exception», dans le Département «Hôtellerie et Ministères». Au cours de ce stage j’ai participé en tant qu’Ingénieur Méthodes-Exploitation à la prise en charge d’un contrat de maintenance multi technique en CVC, plomberie et électricité dans le Pôle Universitaire Léonard de Vinci, situé à la Défense, Paris.
- Published
- 2019
43. Geothermal heat pump in heating mode: Modeling and simulation on TRNSYS
- Author
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Chargui, R., Sammouda, H., and Farhat, A.
- Subjects
- *
GROUND source heat pump systems , *HEATING , *MATHEMATICAL models , *HOME energy use , *COMPUTER simulation , *THERMAL comfort , *HOME air conditioning , *GREENHOUSES - Abstract
Abstract: The consumption of energy in greenhouses and residential buildings has gained an increasing interest. Recently, due to the rising demand for efficient energy use and higher comfort standards, our contribution will relate to an application of heating of a greenhouse by using an abundant and more universal sources and easily accessible. Thus, the resources employed are water or air. The objective of this work is to model and simulate a heat pump on TRNSYS which is dedicated to study the thermodynamic phenomena. Here, we present a mathematical description of the heat pump on TRNSYS model by using HVAC technique, as well as the numerical results of the simulation of the heat pump, such as the COP, power consumption and the delivered power, by using the geothermal source in southern Tunisia. [Copyright &y& Elsevier]
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- 2012
- Full Text
- View/download PDF
44. Steady state vapor compression refrigeration cycle simulation for a monovalent inverter-driven water-to-water heat pump with a desuperheater for low energy houses
- Author
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Blanco, David L., Nagano, Katsunori, and Morimoto, Masahiro
- Subjects
- *
GROUND source heat pump systems , *VAPOR pressure , *REFRIGERATION & refrigerating machinery , *COMPUTER simulation , *HOME energy use , *HOME heating & ventilation , *MATHEMATICAL models , *PERFORMANCE evaluation , *HEAT exchangers - Abstract
Abstract: A steady-state simulation is presented for a monovalent inverter-driven water-to-water heat pump with a desuperheater. For design-oriented simulations, superheating or subcooling degrees are used as input. However, the proposed simulation only uses the system''s refrigerant charge, environmental, and control parameters, which make it particularly useful for off-design evaluations, including the annual performance factor calculation. Block models were used for the compressor and electronic expansion valve, while novel adaptive zone models were used for the heat exchangers. A multivariable error minimization algorithm was used over a sequential component scheme to provide global convergence. The numerical calculations were compared with 118 experimental results. The resulting COP agrees within 10% for 95.77% of the data. The mapping results reveal a maximum COP deviation of 8.78%. Computational results for the studied system reveal that a constant degree of superheating might not always maximize the COP. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
45. Calculations on performance characteristics of counterflow reversibly used cooling towers
- Author
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Zhang, Quan, Wu, Jiasheng, Zhang, Guoqiang, Zhou, Jin, Guo, Yonghui, and Shen, Wei
- Subjects
- *
COOLING towers , *HEAT transfer , *MASS transfer , *APPROXIMATION theory , *TEMPERATURE effect , *THERMAL analysis , *MATHEMATICAL models - Abstract
Abstract: This paper aims at developing an analytical model for the coupled heat and mass transfer processes in a counterflow Reversibly Used Cooling Tower (RUCT) based on operating conditions, which is more realistic than most conventionally adopted Merkel approximations. Temperature and moisture content differences are chosen as the driving forces of heat and mass transfer correspondingly and a system of specific difference equations is developed to solve the model more efficiently. The model is investigated by using an iterative algorithm, which is validated with the experimental data reported. The analytical model also accommodates the direct and quick calculation of air and water temperature profiles, moisture content of air and the water mass flow rate change along the vertical length of the RUCT. With the aid of the developed model, the thermal behavior of the counterflow RUCT under various operating and environmental conditions is also studied in this paper. The results reveal that the proposed model can provide a theoretical foundation for practical design and performance evaluation of counterflow RUCT. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
46. Application of the output dependent feature scaling in modeling and prediction of performance of counter flow vortex tube having various nozzles numbers at different inlet pressures of air, oxygen, nitrogen and argon
- Author
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Polat, Kemal and Kırmacı, Volkan
- Subjects
- *
SCALING laws (Statistical physics) , *PREDICTION models , *VORTEX tubes , *HEATING , *COOLING , *ARTIFICIAL neural networks , *FUZZY logic , *PERFORMANCE evaluation , *TEMPERATURE effect - Abstract
Abstract: In this study, the performance of the counter flow type vortex tube with the input parameters including the nozzle number (N), the densities of inlet gases (air, oxygen, nitrogen, and argon) and the inlet pressure (P inlet) has been modeled with the proposed hybrid method combining a novel data preprocessing called output dependent feature scaling (ODFS) and adaptive network based fuzzy inference system (ANFIS) by using the experimentally obtained data. In the developed system, output parameter temperature gradient between the cold and hot outlets has been determined using input parameters comprising (P inlet), (N), and the density of gases. In order to evaluate the performance of hybrid method, the mean absolute error (MAE), mean square error (MSE), root mean square error (RMSE), determination coefficient (R2), and Index of Agreement (IA) values have been used. The obtained results are 9.0670e-004 (MAE), 5.8563e-006 (MSE), 0.0024 (RMSE), 1.00 (R2), and 1.00 (IA) using the hybrid method. [Copyright &y& Elsevier]
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- 2011
- Full Text
- View/download PDF
47. Resorption system with simultaneous heat and cold production
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Xu, J., Oliveira, R.G., and Wang, R.Z.
- Subjects
- *
ADSORPTION (Chemistry) , *HEATING , *COOLING , *AMMONIA , *REFRIGERATION & refrigerating machinery , *SILICA gel , *CHLORIDES , *LOW temperature engineering - Abstract
Abstract: A resorption system with simultaneous cold and heat production was studied. The heat produced could be used for sanitary or process purposes, or to drive another heat-powered machine. The resorption reactors had MnCl2 and NH4Cl as reactant (which are impregnated in expanded graphite) and NH3 as refrigerant. The combined coefficient of performance and amplification (COPA) of this system reached 1.3 when the cooling effect was produced at 0°C and heating effect at 75°C with the regeneration temperature of 140°C. Its COP was 0.35 with a specific cooling power (SCP) of 1.12MJkg−1 day−1, and the heat sink in this case remained below the cooling temperature for more than 5h. Because of the heat production at certain temperature level (from 70°C to 80°C) in this study, the released heat could be used to power a silica gel-water adsorption chiller and the overall COP of the combined system would increase dramatically. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
48. Experimental analysis and modeling of hydronic radiant ceiling panels using transient-state analysis
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Fonseca, Néstor
- Subjects
- *
RADIANT heating , *EXPERIMENTAL design , *HYDRONICS , *CEILINGS , *BUILDING commissioning , *COOLING , *TEMPERATURE effect - Abstract
Abstract: The model developed in this investigation considers the hydronic panels as a transient-state heat exchanger connected to a detailed lumped transient model of the building. The behavior of the hydronic ceiling system and the interactions with its environment has been experimentally and numerically evaluated. This article presents the results of a study performed to develop a transient model of hydronic ceiling panels in heating or cooling modes and its environment (window, building structure, internal thermal loads and ventilation). Only the dry regime is considered in this case. Using as inputs the hydronic ceiling and room dimensions, material properties and the transient measurements of the air temperature at the adjacent zones, climatic conditions, supply air and water temperatures and mass flow rates, the model permits to estimate the water exhaust temperature, ceiling average surface temperature, resultant and dry air room temperatures, hydronic ceiling power and internal surface temperatures of the room in order to compare with measurements taken during the commissioning process. Two transient tests in heating and cooling modes are used to the experimental validation. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
49. Experimental study of thermal condition in a room with hydronic cooling radiant surfaces
- Author
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Fonseca, Néstor
- Subjects
- *
HYDRONICS , *COOLING , *CEILINGS , *WATER temperature , *VENTILATION , *HEAT transfer , *HEAT convection , *RADIATION - Abstract
Abstract: This paper presents a new approach for experimental analysis of chilled or heated ceiling systems and its environment (ventilation, windows and thermal loads distribution). The work is aimed at giving a better insight to crucial parameters as the contact thermal resistance, fin effectiveness of ceiling panels, mass flow rate, supply water temperature, thermal load distribution, fenestration and ventilation system effects on the radiant ceiling capacity and comfort conditions. The experimental methodology and its discussion are also presented. A test chamber is adapted in a way to reproduce as good as possible the characteristics of a hospital room with a cooling ceiling system. The convection and radiation heat transfer coefficients to room and losses through the ceiling void are also studied. Experimental data are used to fit the uncertain parameters mentioned and improve the capacity and performance of the ceiling system, but also to evaluate the design of this HVAC system and the applicable control strategies. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
50. Observation and theoretical modeling of electron scale solar wind turbulence
- Author
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Sahraoui, Fouad, Goldstein, Melvyn L., Abdul-Kader, K., Belmont, Gérard, Rezeau, Laurence, Robert, Patrick, and Canu, Patrick
- Subjects
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ELECTRON accelerators , *TURBULENCE , *MAGNETOHYDRODYNAMICS , *SOLAR wind , *KOLMOGOROV complexity , *ENERGY dissipation , *SPECTRUM analysis - Abstract
Abstract: Turbulence at MagnetoHydroDynamics (MHD) scales in the solar wind has been studied for more than three decades, using data analysis, theoretical and numerical modeling. However, smaller scales have not been explored until very recently. Here, we review recent results on the first observation of cascade and dissipation of the solar wind turbulence at the electron scales. Thanks to the high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectra of turbulence up to (in the spacecraft reference frame) and found evidence of energy dissipation around the Doppler-shifted electron gyroscale . Before its dissipation, the energy is shown to undergo two cascades: a Kolmogorov-like cascade with a scaling above the proton gyroscale, and a new cascade at the sub-proton and electron gyroscales. Above the spectrum has a steeper power law down to the noise level of the instrument. Solving numerically the linear Maxwell–Vlasov equations combined with recent theoretical predictions of the Gyro-Kinetic theory, we show that the present results are consistent with a scenario of a quasi-two-dimensional cascade into Kinetic Alfvén modes (KAW). New analyses of other data sets, where the Cluster separation (of about ) allowed us to explore the sub-proton scales using the k-filtering technique, and to confirm the 2D nature of the turbulence at those scales. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
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