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Détails du magazine
Format
Magazine
eISSN
2784-1391
Première publication
12 Apr 2013
Période de publication
4 fois par an
Langues
Anglais

Chercher

Volume 10 (2014): Edition 2 (June 2014)

Détails du magazine
Format
Magazine
eISSN
2784-1391
Première publication
12 Apr 2013
Période de publication
4 fois par an
Langues
Anglais

Chercher

5 Articles
access type Accès libre

Mathematical Determination of Thermal Load for Fluidised Bed Furnaces Using Sawdust

Publié en ligne: 10 Jul 2014
Pages: 1 - 10

Résumé

Abstract

For technical applications, a physical model capable of predicting the particle evolution in the burning process along its trajectory through the furnace is very useful. There are two major demands: all the thermo-dynamic processes that describe the particle burning process must be accounted and the model must be written in such equation terms to allow the intervention for parameter settings and particle definition. The computations were performed for the following parameters: furnace average temperature between 700 and 1200 °C, size of the sawdust particle from 4 to 6 mm and fix carbon ignition between 500 and 900 °C. The values obtained for the characteristic parameters of the burning process ranged from 30 to 60 [kg/(h·m3)] for the gravimetrical burning speed WGh and from 150 to 280 [kW/m3] for the volumetric thermal load of the furnace QV. The main conclusion was that the calculus results are in good agreement with the experimental data from the pilot installations and the real-case measurements in the sawdust working boiler furnaces or pre-burning chambers. Another very important conclusion is that the process speed variation, when the furnace temperature changes, confirms the thermo-kinetic predictions, namely that the burning process speed decreases when the furnace temperature increases.

Mots clés

  • particle
  • burning process
  • physical model
  • equations
access type Accès libre

The Tuning of the Fuzzy Controllers Used in the Pervasive Systems

Publié en ligne: 10 Jul 2014
Pages: 11 - 16

Résumé

Abstract

This paper intends to present the differences appearing between the pervasive systems and other usual systems regarding the tuning of the fuzzy controllers. For the pervasive systems used in the intelligent buildings, the emphasize is on the building’s occupant and the used equipment is to be engineered so that the occupant will be as less perturbed by its presence or settings. For the fuzzy controllers used in non-pervasive systems - although the occupants are not working with physical quantities, but with language described variables, the definition of the inputs’ and outputs’ domain values can be modified only by reprogramming.

The result generated by the research work that lays at the basis of the present paper is the tuning of the fuzzy controllers used in pervasive systems. The occupants role is to describe the sensation they have in the very moment, the sensation they would like to have, and the fuzzy controllers’ inputs and outputs will be automatically modified based on different parameters regarding the occupants, for example the clothes worn.

The tuning of the fuzzy controllers for the pervasive systems has not been treated before, the authors intending to make a detailed and deep research in this field.

Mots clés

  • artificial intelligence
  • comfort
  • fuzzy logic
  • predicted mean vote
access type Accès libre

Analyses of CO2 Time Variation Records in Naturally Ventilated Occupied Spaces

Publié en ligne: 10 Jul 2014
Pages: 17 - 24

Résumé

Abstract

The present paper concerns the results obtained in a human subject experimental study, regarding the predefined occupant behavior with respect to aerating activities of a naturally ventilated space. During the experiment, various scenarios were investigated of different occupant’s behavior patterns with regard to the degree of window opening. Indoor air temperature, relative humidity and CO2 volume fraction, were continuously measured and recorded. CO2 concentration time variation records were analyzed separately and the time change of this parameter was considered as a main indicator to distinguish the periods of infiltration only and the periods of conscious aeration activities, performed by the occupants. The developed evaluation procedures as well as the key results from the analyses are discussed in the paper.

Mots clés

  • Indoor Air Quality (IAQ)
  • CO2 concentration
  • Occupant Behavior
  • Aeration
access type Accès libre

Water Quality Improvement Using Renewable Energies

Publié en ligne: 10 Jul 2014
Pages: 25 - 30

Résumé

Abstract

To reduce the negative effects of eutrophication processes in water bodies it is necessary to improve water quality by ensuring the necessary oxygen concentration. The paper proposes a new innovative solution for the improvement of lake water quality. The premises for the implementation of the experimental floating platform which will aerate the lake waters will be presented. To give a specific view over the oxygen dispersion into the lake, numerical simulations in CFD software will be presented in different cases.

The protection of drinking water resources against pollution is a common task of outstanding importance for the water management and environment protection sectors. To prevent water supply problems arising from the short and medium-term quality deterioration of resources caused by pollution incidents, it is vital to develop methods for monitoring the quality of resources as well as methods for monitoring and predicting serious pollution events to protect water users. In the case of vulnerable drinking water resources, the establishment and maintenance of an early warning monitoring system is important. Emergency treatment technologies are also needed by the waterworks to treat the water for periods when the quality of the water has temporarily deteriorated.

Innovative solutions for the improvement of water quality consist in using a floating platform equipped with aeration systems. The equipment used to aerate the lake waters is powered by the area renewable energy (solar, wind). So, this platform can be used in isolated area, where there is no energy supply from the national network.

Mots clés

  • Aeration
  • renewable energies
  • numerical simulation
access type Accès libre

Mathematical Modelling of a Hybrid Micro-Cogeneration Group Based on a Four Stroke Diesel Engine

Publié en ligne: 10 Jul 2014
Pages: 31 - 36

Résumé

Abstract

The paper presents a part of the work conducted in the first stage of a Research Grant called ”Hybrid micro-cogeneration group of high efficiency equipped with an electronically assisted ORC” acronym GRUCOHYB. The hybrid micro-cogeneration group is equipped with a four stroke Diesel engine having a maximum power of 40 kW. A mathematical model of the internal combustion engine is presented. The mathematical model is developed based on the Laws of Thermodynamics and takes into account the real, irreversible processes. Based on the mathematical model a computation program was developed. The results obtained were compared with those provided by the Diesel engine manufacturer. Results show a very high correlation between the manufacturer’s data and the simulation results for an engine running at 100% load. Future developments could involve using an exergetic analysis to show the ability of the ORC to generate electricity from recovered heat

Mots clés

  • irreversible processes
  • simulation
  • variable operation parameters
  • result validation
5 Articles
access type Accès libre

Mathematical Determination of Thermal Load for Fluidised Bed Furnaces Using Sawdust

Publié en ligne: 10 Jul 2014
Pages: 1 - 10

Résumé

Abstract

For technical applications, a physical model capable of predicting the particle evolution in the burning process along its trajectory through the furnace is very useful. There are two major demands: all the thermo-dynamic processes that describe the particle burning process must be accounted and the model must be written in such equation terms to allow the intervention for parameter settings and particle definition. The computations were performed for the following parameters: furnace average temperature between 700 and 1200 °C, size of the sawdust particle from 4 to 6 mm and fix carbon ignition between 500 and 900 °C. The values obtained for the characteristic parameters of the burning process ranged from 30 to 60 [kg/(h·m3)] for the gravimetrical burning speed WGh and from 150 to 280 [kW/m3] for the volumetric thermal load of the furnace QV. The main conclusion was that the calculus results are in good agreement with the experimental data from the pilot installations and the real-case measurements in the sawdust working boiler furnaces or pre-burning chambers. Another very important conclusion is that the process speed variation, when the furnace temperature changes, confirms the thermo-kinetic predictions, namely that the burning process speed decreases when the furnace temperature increases.

Mots clés

  • particle
  • burning process
  • physical model
  • equations
access type Accès libre

The Tuning of the Fuzzy Controllers Used in the Pervasive Systems

Publié en ligne: 10 Jul 2014
Pages: 11 - 16

Résumé

Abstract

This paper intends to present the differences appearing between the pervasive systems and other usual systems regarding the tuning of the fuzzy controllers. For the pervasive systems used in the intelligent buildings, the emphasize is on the building’s occupant and the used equipment is to be engineered so that the occupant will be as less perturbed by its presence or settings. For the fuzzy controllers used in non-pervasive systems - although the occupants are not working with physical quantities, but with language described variables, the definition of the inputs’ and outputs’ domain values can be modified only by reprogramming.

The result generated by the research work that lays at the basis of the present paper is the tuning of the fuzzy controllers used in pervasive systems. The occupants role is to describe the sensation they have in the very moment, the sensation they would like to have, and the fuzzy controllers’ inputs and outputs will be automatically modified based on different parameters regarding the occupants, for example the clothes worn.

The tuning of the fuzzy controllers for the pervasive systems has not been treated before, the authors intending to make a detailed and deep research in this field.

Mots clés

  • artificial intelligence
  • comfort
  • fuzzy logic
  • predicted mean vote
access type Accès libre

Analyses of CO2 Time Variation Records in Naturally Ventilated Occupied Spaces

Publié en ligne: 10 Jul 2014
Pages: 17 - 24

Résumé

Abstract

The present paper concerns the results obtained in a human subject experimental study, regarding the predefined occupant behavior with respect to aerating activities of a naturally ventilated space. During the experiment, various scenarios were investigated of different occupant’s behavior patterns with regard to the degree of window opening. Indoor air temperature, relative humidity and CO2 volume fraction, were continuously measured and recorded. CO2 concentration time variation records were analyzed separately and the time change of this parameter was considered as a main indicator to distinguish the periods of infiltration only and the periods of conscious aeration activities, performed by the occupants. The developed evaluation procedures as well as the key results from the analyses are discussed in the paper.

Mots clés

  • Indoor Air Quality (IAQ)
  • CO2 concentration
  • Occupant Behavior
  • Aeration
access type Accès libre

Water Quality Improvement Using Renewable Energies

Publié en ligne: 10 Jul 2014
Pages: 25 - 30

Résumé

Abstract

To reduce the negative effects of eutrophication processes in water bodies it is necessary to improve water quality by ensuring the necessary oxygen concentration. The paper proposes a new innovative solution for the improvement of lake water quality. The premises for the implementation of the experimental floating platform which will aerate the lake waters will be presented. To give a specific view over the oxygen dispersion into the lake, numerical simulations in CFD software will be presented in different cases.

The protection of drinking water resources against pollution is a common task of outstanding importance for the water management and environment protection sectors. To prevent water supply problems arising from the short and medium-term quality deterioration of resources caused by pollution incidents, it is vital to develop methods for monitoring the quality of resources as well as methods for monitoring and predicting serious pollution events to protect water users. In the case of vulnerable drinking water resources, the establishment and maintenance of an early warning monitoring system is important. Emergency treatment technologies are also needed by the waterworks to treat the water for periods when the quality of the water has temporarily deteriorated.

Innovative solutions for the improvement of water quality consist in using a floating platform equipped with aeration systems. The equipment used to aerate the lake waters is powered by the area renewable energy (solar, wind). So, this platform can be used in isolated area, where there is no energy supply from the national network.

Mots clés

  • Aeration
  • renewable energies
  • numerical simulation
access type Accès libre

Mathematical Modelling of a Hybrid Micro-Cogeneration Group Based on a Four Stroke Diesel Engine

Publié en ligne: 10 Jul 2014
Pages: 31 - 36

Résumé

Abstract

The paper presents a part of the work conducted in the first stage of a Research Grant called ”Hybrid micro-cogeneration group of high efficiency equipped with an electronically assisted ORC” acronym GRUCOHYB. The hybrid micro-cogeneration group is equipped with a four stroke Diesel engine having a maximum power of 40 kW. A mathematical model of the internal combustion engine is presented. The mathematical model is developed based on the Laws of Thermodynamics and takes into account the real, irreversible processes. Based on the mathematical model a computation program was developed. The results obtained were compared with those provided by the Diesel engine manufacturer. Results show a very high correlation between the manufacturer’s data and the simulation results for an engine running at 100% load. Future developments could involve using an exergetic analysis to show the ability of the ORC to generate electricity from recovered heat

Mots clés

  • irreversible processes
  • simulation
  • variable operation parameters
  • result validation

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