Ababacar Thiam - Academia.edu (original) (raw)

Papers by Ababacar Thiam

JP Journal of Heat and Mass Transfer

Poultry is a vital sector for emerging economies like Senegal. Climatic Ousmane Diop et al. 98 co... more Poultry is a vital sector for emerging economies like Senegal. Climatic Ousmane Diop et al. 98 conditions during the dry season are not favourable for poultry houses. Conventionally, naturally ventilated poultry houses with transverse or single-sided openings are used to combat heat stress in chickens. Thus, this study aims to analyze the thermal performance of a naturally ventilated poultry house with openings on a single facade in hot and semi-arid climate regions. The ambient parameters such as temperature, relative humidity and air velocity were measured in the poultry house during the hot period from the chickens' third to the fifth week of life. The results show that the interior temperatures in the poultry house vary between 36°C and 42°C at maximum solar irradiance for humidity varying from 11 to 36%. The air velocity in the poultry house below 1.5m/s does not allow the heat accumulated in the poultry house to be evacuated. The temperature-humidity index (THI) of the test day of April 9, 2022 corresponding to the beginning of the fourth week of growth of the chickens ranged from 70 to 93 between 11:00h a.m. and 08:00h p.m., showing discomfort in the poultry house during the day. A mortality of 6.5% was recorded when the THI reaches 93 in the poultry house.

Lecture Notes in Computer Science, 2022

Heliyon

The efficiency and performance of solar tower power are greatly influenced by the heliostats fiel... more The efficiency and performance of solar tower power are greatly influenced by the heliostats field. To ensure accurate tracking of reflectors often requires an evaluation of the beam reflected positions. This operation is costly time-consuming due to the number of heliostats. It is also necessary to set up a fast and less expensive method able to evaluate tracking heliostat. In this paper, prediction models based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN) were applied to estimate rapidly and accurately heliostat error tracking. The modeling is based on the experimental data of seven different days. The input parameters are time and day number and the output is the beam reflected position following the altitude and azimuth axes. Both techniques have been able to predict the beam reflected position. A comparison of results showed that intelligent methods recorded better performance than conventional model based on geometric errors. For ANFIS model, coefficients of correlation (R2) of 0.97 is obtained compared to that of the ANN, 0.96 and 0.92 for altitude and azimuth axes respectively. The intelligent methods may be a promising alternative for predicting heliostat beam reflected the position.

Case Studies in Thermal Engineering, Sep 1, 2017

Abstract This work presents an experimental study of H 2 0-NH 3 -H 2 diffusion absorption refrige... more Abstract This work presents an experimental study of H 2 0-NH 3 -H 2 diffusion absorption refrigeration under two types of energy sources, i.e. the conventional electric energy from grid (electric) and exhaust gas from internal combustion engine. Dynamic method is used to evaluate the behavior of the components of the system for both energy sources. Results obtained show that the performance of each component under different types of energy sources is almost coherent. For the generator, the electrical heater system requires more time to warm up, around three minutes, compared to the 40 s for system running with exhaust gas. For the evaporator, the decreasing rate is higher for the exhaust gas source and it took only about two hours to reach steady-state while for the electrical heat, the steady-state is reached after about seven hours of operation. For both energy sources, the evaporation temperature stabilizes to 3 °C and the minimum temperature to boil off ammonia is around 140 °C.

Fluid Dynamics & Materials Processing

A study is conducted to optimize the geometry of a solar chimney equipped with a horizontal absor... more A study is conducted to optimize the geometry of a solar chimney equipped with a horizontal absorber in order to improve its performances in relation to the provision of ventilation. The problem is tackled through numerical solution of the governing equations for mass, momentum and energy in their complete three-dimensional and unsteady formulation. The numerical framework also includes a turbulence model (k-ε) and a radiant heat transfer (DO) model. Moreover, a Multi-Objective Genetic Algorithm (MOGA) is employed to derive the optimal configuration of the considered solar chimney. It is shown that an air velocity of 0.2 m/s can be obtained. This value is the minimum allowed air velocity according to the ASHRAE' s (American Society of Heating, Refrigerating and AirConditioning Engineers) adaptive comfort approach. KEYWORDS Natural ventilation; adaptative comfort; solar chimney; fluent; MOGA Nomenclature Greek letters Units absorptivity dissipation rate Reynolds stress tensor turbulence kinetic energy Density (Kg/m 3) Stepan's coefficient (W/m 2 /K 4) turbulent Prandtl numbers for k turbulent Prandtl numbers for e Thermal Expansion Coefficient (1/K) This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

EPJ Photovoltaics

The performance of large-scale PV solar plant installed in sub-Saharan regions is affected by the... more The performance of large-scale PV solar plant installed in sub-Saharan regions is affected by the deposition of dust on the surface of the PV modules. Frequent cleaning of the PV modules increases the profitability of PV solar plants. The objective of this study is to determine the optimal cleaning cycle of a PV solar plant subjected to a wind loaded with sand and dust. This study took place in a PV solar plant installed in Senegal. The measurement data are analysed for a period of two years and used to extract soiling rate. Optimization was done based on the total cost caused by dust on the PV solar plant to minimize the number of days between cleaning events. The results showed that the soiling rate between June and May is 0.34%/day, while a rate of 0.33%/day was recorded in October. The highest soiling rates of 0.42%/day and 0.49%/day were recorded in December and between February and March, respectively. The optimal cleaning cycle for the PV solar plant is 14 days. The total cos...

Fluid Dynamics & Materials Processing

The operating temperature is a critical factor affecting the performances of photovoltaic (PV) mo... more The operating temperature is a critical factor affecting the performances of photovoltaic (PV) modules. In this work, relevant models are proposed for the prediction of this operating temperature using data (ambient temperature and solar irradiance) based on real measurements conducted in the tropical region. For each weather condition (categorized according to irradiance and temperature levels), the temperatures of the PV modules obtained using the proposed approach is compared with the corresponding experimentally measured value. The results show that the proposed models have a smaller Root Mean Squared Error than other models developed in the literature for all weather conditions, which confirms the reliability of the proposed framework.

International Journal of Photoenergy, 2021

This work investigated the prediction of the optimum height and tilt angle of the solar receiver ... more This work investigated the prediction of the optimum height and tilt angle of the solar receiver of a 30 kWe solar tower power plant for the electricity production in the Sahelian zone. Initially, the solar field is sized to determine the total reflecting surface area of the mirrors and the number of heliostats. A PS10-like radially staggered heliostat field is used to design the heliostat layout in the field using a Matlab code. The concentrated solar flux at the input of the receiver was determined using Soltrace software by the Monte Carlo ray tracing (MCRT) method. The sizing results show that the total reflecting surface area is 350 m2 for an optical efficiency of 76.4% and a reference DNI of 600 W/m2. The solar field layout indicates 175 heliostats of 2 m2 surface area and 1.5 m height each. The simulation results show that the optimum height and tilt angle of the solar receiver are 26 m and 65°, respectively.

Case Studies in Thermal Engineering, 2022

Lecture Notes in Electrical Engineering, 2021

When using Hartree-Fock (HF) trial wave functions in quantum Monte Carlo calculations, one faces,... more When using Hartree-Fock (HF) trial wave functions in quantum Monte Carlo calculations, one faces, in case of HF instabilities, the HF symmetry dilemma in choosing between the symmetryadapted solution of higher HF energy and symmetry-broken solutions of lower HF energies. In this work, we have examined the HF symmetry dilemma in hydrogen rings which present singlet instabilities for sufficiently large rings. We have found that the symmetry-adapted HF wave function gives a lower energy both in variational Monte Carlo and in fixed-node diffusion Monte Carlo. This indicates that the symmetry-adapted wave function has more accurate nodes than the symmetry-broken wave functions, and thus suggests that spatial symmetry is an important criterion for selecting good trial wave functions.

EAI Endorsed Transactions on Collaborative Computing, 2017

This paper investigated the impact of Window to Wall Ratios (WWR) an the thermal comfort and ener... more This paper investigated the impact of Window to Wall Ratios (WWR) an the thermal comfort and energy lighting demand of a building in tropical zone. Simulations were carried out for a reference office proposed by Task 27 of IEA using three Window to Wall Ratios (WWR). Results were analyzed both in terms of operative temperature and energy lighting consumption. Simulations results showed that for increasing WWR, the operative temperature increases and energy lighting demand decreases.

EAI Endorsed Transactions on Collaborative Computing, 2017

Reducing global energy consumption is a challenge to limit the rise in average earth temperature.... more Reducing global energy consumption is a challenge to limit the rise in average earth temperature. The use of lighting controls in the building leads to energy savings. The objective of this study is to evaluate the energy savings potential in buildings in tropical zone due to lighting controls. The results of the simulations show that 47.6% of energy savings could be obtained with a dimming control and 33.3% with an on/off control in this office considered.

SSRN Electronic Journal, 2021

Journal of Power and Energy Engineering, 2017

SOLARPACES 2018: International Conference on Concentrating Solar Power and Chemical Energy Systems, 2019

Journal of Material Science & Engineering, 2015

A membrane distillation process using solar energy has been studied. This system has been modelle... more A membrane distillation process using solar energy has been studied. This system has been modelled to provide approximations of the flow of distillate, the thermal effectiveness and the quantities of heat exchanged by conduction and evaporation during the production process of water. Then, simulations have been carried out using MATLAB to highlight the transfers of mass and energy in a dynamic regime under the effect of variable solar radiation and to illustrate the temporal evolution of the parameters related to the operation of the membrane. So, to estimate the production of water, a polynomial approximation was used.

Case Studies in Thermal Engineering, 2021

2021 IEEE 1st International Maghreb Meeting of the Conference on Sciences and Techniques of Automatic Control and Computer Engineering MI-STA

Journal de Physique de la SOAPHYS

JP Journal of Heat and Mass Transfer

Poultry is a vital sector for emerging economies like Senegal. Climatic Ousmane Diop et al. 98 co... more Poultry is a vital sector for emerging economies like Senegal. Climatic Ousmane Diop et al. 98 conditions during the dry season are not favourable for poultry houses. Conventionally, naturally ventilated poultry houses with transverse or single-sided openings are used to combat heat stress in chickens. Thus, this study aims to analyze the thermal performance of a naturally ventilated poultry house with openings on a single facade in hot and semi-arid climate regions. The ambient parameters such as temperature, relative humidity and air velocity were measured in the poultry house during the hot period from the chickens' third to the fifth week of life. The results show that the interior temperatures in the poultry house vary between 36°C and 42°C at maximum solar irradiance for humidity varying from 11 to 36%. The air velocity in the poultry house below 1.5m/s does not allow the heat accumulated in the poultry house to be evacuated. The temperature-humidity index (THI) of the test day of April 9, 2022 corresponding to the beginning of the fourth week of growth of the chickens ranged from 70 to 93 between 11:00h a.m. and 08:00h p.m., showing discomfort in the poultry house during the day. A mortality of 6.5% was recorded when the THI reaches 93 in the poultry house.

Lecture Notes in Computer Science, 2022

Heliyon

The efficiency and performance of solar tower power are greatly influenced by the heliostats fiel... more The efficiency and performance of solar tower power are greatly influenced by the heliostats field. To ensure accurate tracking of reflectors often requires an evaluation of the beam reflected positions. This operation is costly time-consuming due to the number of heliostats. It is also necessary to set up a fast and less expensive method able to evaluate tracking heliostat. In this paper, prediction models based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) and Artificial Neural Network (ANN) were applied to estimate rapidly and accurately heliostat error tracking. The modeling is based on the experimental data of seven different days. The input parameters are time and day number and the output is the beam reflected position following the altitude and azimuth axes. Both techniques have been able to predict the beam reflected position. A comparison of results showed that intelligent methods recorded better performance than conventional model based on geometric errors. For ANFIS model, coefficients of correlation (R2) of 0.97 is obtained compared to that of the ANN, 0.96 and 0.92 for altitude and azimuth axes respectively. The intelligent methods may be a promising alternative for predicting heliostat beam reflected the position.

Case Studies in Thermal Engineering, Sep 1, 2017

Abstract This work presents an experimental study of H 2 0-NH 3 -H 2 diffusion absorption refrige... more Abstract This work presents an experimental study of H 2 0-NH 3 -H 2 diffusion absorption refrigeration under two types of energy sources, i.e. the conventional electric energy from grid (electric) and exhaust gas from internal combustion engine. Dynamic method is used to evaluate the behavior of the components of the system for both energy sources. Results obtained show that the performance of each component under different types of energy sources is almost coherent. For the generator, the electrical heater system requires more time to warm up, around three minutes, compared to the 40 s for system running with exhaust gas. For the evaporator, the decreasing rate is higher for the exhaust gas source and it took only about two hours to reach steady-state while for the electrical heat, the steady-state is reached after about seven hours of operation. For both energy sources, the evaporation temperature stabilizes to 3 °C and the minimum temperature to boil off ammonia is around 140 °C.

Fluid Dynamics & Materials Processing

A study is conducted to optimize the geometry of a solar chimney equipped with a horizontal absor... more A study is conducted to optimize the geometry of a solar chimney equipped with a horizontal absorber in order to improve its performances in relation to the provision of ventilation. The problem is tackled through numerical solution of the governing equations for mass, momentum and energy in their complete three-dimensional and unsteady formulation. The numerical framework also includes a turbulence model (k-ε) and a radiant heat transfer (DO) model. Moreover, a Multi-Objective Genetic Algorithm (MOGA) is employed to derive the optimal configuration of the considered solar chimney. It is shown that an air velocity of 0.2 m/s can be obtained. This value is the minimum allowed air velocity according to the ASHRAE' s (American Society of Heating, Refrigerating and AirConditioning Engineers) adaptive comfort approach. KEYWORDS Natural ventilation; adaptative comfort; solar chimney; fluent; MOGA Nomenclature Greek letters Units absorptivity dissipation rate Reynolds stress tensor turbulence kinetic energy Density (Kg/m 3) Stepan's coefficient (W/m 2 /K 4) turbulent Prandtl numbers for k turbulent Prandtl numbers for e Thermal Expansion Coefficient (1/K) This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

EPJ Photovoltaics

The performance of large-scale PV solar plant installed in sub-Saharan regions is affected by the... more The performance of large-scale PV solar plant installed in sub-Saharan regions is affected by the deposition of dust on the surface of the PV modules. Frequent cleaning of the PV modules increases the profitability of PV solar plants. The objective of this study is to determine the optimal cleaning cycle of a PV solar plant subjected to a wind loaded with sand and dust. This study took place in a PV solar plant installed in Senegal. The measurement data are analysed for a period of two years and used to extract soiling rate. Optimization was done based on the total cost caused by dust on the PV solar plant to minimize the number of days between cleaning events. The results showed that the soiling rate between June and May is 0.34%/day, while a rate of 0.33%/day was recorded in October. The highest soiling rates of 0.42%/day and 0.49%/day were recorded in December and between February and March, respectively. The optimal cleaning cycle for the PV solar plant is 14 days. The total cos...

Fluid Dynamics & Materials Processing

The operating temperature is a critical factor affecting the performances of photovoltaic (PV) mo... more The operating temperature is a critical factor affecting the performances of photovoltaic (PV) modules. In this work, relevant models are proposed for the prediction of this operating temperature using data (ambient temperature and solar irradiance) based on real measurements conducted in the tropical region. For each weather condition (categorized according to irradiance and temperature levels), the temperatures of the PV modules obtained using the proposed approach is compared with the corresponding experimentally measured value. The results show that the proposed models have a smaller Root Mean Squared Error than other models developed in the literature for all weather conditions, which confirms the reliability of the proposed framework.

International Journal of Photoenergy, 2021

This work investigated the prediction of the optimum height and tilt angle of the solar receiver ... more This work investigated the prediction of the optimum height and tilt angle of the solar receiver of a 30 kWe solar tower power plant for the electricity production in the Sahelian zone. Initially, the solar field is sized to determine the total reflecting surface area of the mirrors and the number of heliostats. A PS10-like radially staggered heliostat field is used to design the heliostat layout in the field using a Matlab code. The concentrated solar flux at the input of the receiver was determined using Soltrace software by the Monte Carlo ray tracing (MCRT) method. The sizing results show that the total reflecting surface area is 350 m2 for an optical efficiency of 76.4% and a reference DNI of 600 W/m2. The solar field layout indicates 175 heliostats of 2 m2 surface area and 1.5 m height each. The simulation results show that the optimum height and tilt angle of the solar receiver are 26 m and 65°, respectively.

Case Studies in Thermal Engineering, 2022

Lecture Notes in Electrical Engineering, 2021

When using Hartree-Fock (HF) trial wave functions in quantum Monte Carlo calculations, one faces,... more When using Hartree-Fock (HF) trial wave functions in quantum Monte Carlo calculations, one faces, in case of HF instabilities, the HF symmetry dilemma in choosing between the symmetryadapted solution of higher HF energy and symmetry-broken solutions of lower HF energies. In this work, we have examined the HF symmetry dilemma in hydrogen rings which present singlet instabilities for sufficiently large rings. We have found that the symmetry-adapted HF wave function gives a lower energy both in variational Monte Carlo and in fixed-node diffusion Monte Carlo. This indicates that the symmetry-adapted wave function has more accurate nodes than the symmetry-broken wave functions, and thus suggests that spatial symmetry is an important criterion for selecting good trial wave functions.

EAI Endorsed Transactions on Collaborative Computing, 2017

This paper investigated the impact of Window to Wall Ratios (WWR) an the thermal comfort and ener... more This paper investigated the impact of Window to Wall Ratios (WWR) an the thermal comfort and energy lighting demand of a building in tropical zone. Simulations were carried out for a reference office proposed by Task 27 of IEA using three Window to Wall Ratios (WWR). Results were analyzed both in terms of operative temperature and energy lighting consumption. Simulations results showed that for increasing WWR, the operative temperature increases and energy lighting demand decreases.

EAI Endorsed Transactions on Collaborative Computing, 2017

Reducing global energy consumption is a challenge to limit the rise in average earth temperature.... more Reducing global energy consumption is a challenge to limit the rise in average earth temperature. The use of lighting controls in the building leads to energy savings. The objective of this study is to evaluate the energy savings potential in buildings in tropical zone due to lighting controls. The results of the simulations show that 47.6% of energy savings could be obtained with a dimming control and 33.3% with an on/off control in this office considered.

SSRN Electronic Journal, 2021

Journal of Power and Energy Engineering, 2017

SOLARPACES 2018: International Conference on Concentrating Solar Power and Chemical Energy Systems, 2019

Journal of Material Science & Engineering, 2015

A membrane distillation process using solar energy has been studied. This system has been modelle... more A membrane distillation process using solar energy has been studied. This system has been modelled to provide approximations of the flow of distillate, the thermal effectiveness and the quantities of heat exchanged by conduction and evaporation during the production process of water. Then, simulations have been carried out using MATLAB to highlight the transfers of mass and energy in a dynamic regime under the effect of variable solar radiation and to illustrate the temporal evolution of the parameters related to the operation of the membrane. So, to estimate the production of water, a polynomial approximation was used.

Case Studies in Thermal Engineering, 2021

2021 IEEE 1st International Maghreb Meeting of the Conference on Sciences and Techniques of Automatic Control and Computer Engineering MI-STA

Journal de Physique de la SOAPHYS