Sami Barbouchi - Academia.edu (original) (raw)

Papers by Sami Barbouchi

Renewable Energy, May 1, 2018

Towards the improvement of the mesoscale modeling for offshore wind application, the real time ob... more Towards the improvement of the mesoscale modeling for offshore wind application, the real time observational nudging capability of the Weather Research and Forecasting (WRF) model has been implemented aiming for enhanced model performance. Utilizing three different horizontal levels of the offshore meteorological mast, FINO3, in the North Sea, wind speed observations were integrated into the model core. The performance of this modified model was then assessed for three different atmospheric stability conditions. Results from this study, illustrate that for all three stratification cases, there is a significant improvement in model performance when using observational nudging showing a reduction in Root Mean Square Error of up to 27% when compared to the observations from FINO1 platform. This study suggests that observational nudging takes a step towards more accurate simulations in wind resource assessment (WRA).

Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to... more Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to onshore, offshore wind farms require larger installation and incur higher O&M costs due to the challenges of the marine environment. In this context condition monitoring systems have an important role to play in reducing maintenance costs. The high initial cost of condition monitoring systems motivates this analysis of the cost effectiveness of such technology O&M cost data are commercially sensitive and generally protected by the wind industry, especially for offshore operations. Component failure rates are essential for modelling wind turbine O&M costs but very little offshore failure rate data available in the public domain. With cooperation of the operator of the largest onshore wind farm in the UK and that of a large Swedish offshore wind farm, three years of operational data records have been made available for this research. With wind and wave parameters extracted from the databa...

The invention relates to the treatment against corrosion of a hollow metal structure containing a... more The invention relates to the treatment against corrosion of a hollow metal structure containing an aqueous medium, and is provided for this purpose: - a supply reservoir metal hydroxide in the structure (10), - an energy generator electrical (G) for promoting an oxidation-reduction reaction in which metal ions react with the carbonate from the aqueous medium to form a layer of metal carbonate, protective against corrosion on an inner wall of the structure acting to electrode in the oxidation-reduction reaction, and in that the device further comprises: - at least one sensor (13, 11) for measuring at least one parameter of the aqueous medium connected to a control module (12) of the generator (G) and / or an opening member (VA) of the reservoir (10) for, based on the measurement of said parameter, applying an additional supply of metal hydroxide in the medium and / or apply a greater contribution plementary into electrical energy.

The cost effectiveness of condition monitoring systems for offshore wind energy is uncertain and ... more The cost effectiveness of condition monitoring systems for offshore wind energy is uncertain and thus a research concern. Unlike onshore wind turbines, the O&M costs of offshore wind turbines are directly affected by the marine environment, mainly wind and wave conditions, and vessel costs are a main contributor to offshore O&M costs. The lack of offshore O&M data makes wind turbine component failure rates essential for component risk assessment and cost model design. However, the failure rate data, especially from the offshore turbines, are highly protected by the manufacturers and the offshore operators. The method developed in this paper deals with this lack of data by adjusting onshore failure rate data to offshore to account for the different operational conditions. Internal cooperation of a large onshore wind farm in the UK and a large Swedish offshore wind farm has been reached, and three-year-period operational data records are used for this research. Both the sites use Siem...

Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind... more Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind Farm (OWF) project lifecycle expenditure according to a range of studies. In this respect, identifying factors affecting operational costs and availability are vital for wind farm operators to achieve the most profitable decisions. Many OWFs are built in stages and the important factors may not be consistent for the different phases. To address this issue, three OWF case studies are defined to represent two phases and a complete project. An initial qualitative screening sensitivity analysis was conducted to identify the most important factors of O&M affecting operating cost and availability. The study concluded that the important factors for total O&M cost were access and repair costs along with failure rates for both minor and major repairs. For time-based availability, the important factors identified were those related to the length of time conducting the maintenance tasks, i.e. the ...

Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind... more Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind Farm (OWF) project lifecycle expenditure according to a range of studies. In this respect, identifying factors affecting operational costs and availability are vital for wind farm operators to achieve the most profitable decisions. Many OWFs are built in stages and the important factors may not be consistent for the different phases. To address this issue, three OWF case studies are defined to represent two phases and a complete project. An initial qualitative screening sensitivity analysis was conducted to identify the most important factors of O&M affecting operating cost and availability. The study concluded that the important factors for total O&M cost were access and repair costs along with failure rates for both minor and major repairs. For time-based availability, the important factors identified were those related to the length of time conducting the maintenance tasks, i.e. the ...

Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to... more Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to onshore, offshore wind farms require larger installation and incur higher O&M costs due to the challenges of the marine environment. In this context condition monitoring systems have an important role to play in reducing maintenance costs. The high initial cost of condition monitoring systems motivates this analysis of the cost effectiveness of such technology O&M cost data are commercially sensitive and generally protected by the wind industry, especially for offshore operations. Component failure rates are essential for modelling wind turbine O&M costs but very little offshore failure rate data available in the public domain. With cooperation of the operator of the largest onshore wind farm in the UK and that of a large Swedish offshore wind farm, three years of operational data records have been made available for this research. With wind and wave parameters extracted from the database and set as inputs to a cost model is has been possible to compare the O&M cost of reactive maintenance with condition based maintenance. The cost model available uses empirical failure rate based on onshore data and so will not fully represent the offshore situation as failure rates are expected to affected by offshore operational conditions. To overcome this limitation, a mathematical translation of failure rate from onshore to offshore is applied to the operational data. The way this translation is calculated is sensitive to the way the relevant probability distributions are represented and improved curve fitting approaches have been explored.

The method involves operating a low pressure compressor (1) and a high pressure compressor (2) at... more The method involves operating a low pressure compressor (1) and a high pressure compressor (2) at rotational speeds lower than nominal speeds of the compressors, where the rotational speed of the high pressure compressor is higher than the rotational speed of the low pressure compressor. The high pressure compressor maintains the rotational speed to be higher than that of the lower pressure compressor during acceleration or deceleration of the rotational speeds. An independent claim is also included for a thermodynamic device comprising a low pressure compressor.

Volume 6: Ocean Space Utilization; Ocean Renewable Energy, 2016

This article explores the application of a binary genetic algorithm and a binary particle swarm o... more This article explores the application of a binary genetic algorithm and a binary particle swarm optimizer to the optimization of an offshore wind farm layout. The framework developed as part of this work makes use of a modular design to include a detailed assessment of a wind farm’s layout including validated analytic wake modeling, cost assessment, and the design of the necessary electrical infrastructure considering constraints. This study has found that both algorithms are capable of optimizing wind farm layouts with respect to levelized cost of energy when using a detailed, complex evaluation function. Both are also capable of identifying layouts with lower levelized costs of energy than similar studies that have been published in the past and are therefore both applicable to this problem. The performance of both algorithms has highlighted that both should be further tuned and benchmarked in order to better characterize their performance.

Ocean Engineering, 2017

This article explores the application of a wind farm layout evaluation function and layout optimi... more This article explores the application of a wind farm layout evaluation function and layout optimization framework to Middelgrunden wind farm in Denmark. This framework has been built considering the interests of wind farm developers in order to aid in the planning of future offshore wind farms using the UK Round 3 wind farms as a point of reference to calibrate the model. The present work applies the developed evaluation tool to estimate the cost, energy production, and the levelized cost of energy for the existing as-built layout at Middelgrunden wind farm; comparing these against the cost and energy production reported by the wind farm operator. From here, new layouts have then been designed using either a genetic algorithm or a particle swarm optimizer. This study has found that both optimization algorithms are capable of identifying layouts with reduced levelized cost of energy compared to the existing layout while still considering the specific conditions and constraints at this site and those typical of future projects. Reductions in levelized cost of energy such as this can result in significant savings over the lifetime of the project thereby highlighting the need for including new advanced methods to wind farm layout design.

In existing houses equipped with hydronic networks and radiators, the supply water temperature ca... more In existing houses equipped with hydronic networks and radiators, the supply water temperature can exceed 65°C the coldest days to ensure required comfort conditions. So to replace old boilers by heat pumps, it is necessary that the heat pumps produce water at high temperature the coldest days. In order to analyze their behavior and measure their performances, field-test has been carried out in France on air to water heat pump designed to replace fuel boilers. The results of the field-test has allowed expressing the thermal energy produced and the electrical energy consumed by the heat pump as a function of the average daily outdoor air temperature. So it is possible with weather data of different climate areas to calculate the thermal and electrical energies and so estimate the Heating Seasonal Performance Factor.

Renewable Energies Offshore, 2015

Failure Modes Effect Analysis (FMEA), or more specifically, Failure Modes Effect and Criticality ... more Failure Modes Effect Analysis (FMEA), or more specifically, Failure Modes Effect and Criticality Analysis (FMECA) has been accepted as an effective condition monitoring assessment tool used widely by the mili-tary, traditional industries and reliability relevant engineering systems. A successful FMEA assists to identity, evaluate and report component failure modes, their severity and impact on the systems. FMEA has been al-ready applied to onshore wind turbines, but there is a lack of offshore wind turbine applications. FMEA can be quantified by using the metric of Risk Priority Number (RPN), defined as the product of the levels of event severity, occurrence frequency and detectability. This paper presents an approach that allows the application of RPN to offshore wind energy by identifying correction factors to existing onshore RPN values taken from previous research. This approach estimates offshore failure rates for key wind turbine components from onshore data.

Renewable Energy, May 1, 2018

Towards the improvement of the mesoscale modeling for offshore wind application, the real time ob... more Towards the improvement of the mesoscale modeling for offshore wind application, the real time observational nudging capability of the Weather Research and Forecasting (WRF) model has been implemented aiming for enhanced model performance. Utilizing three different horizontal levels of the offshore meteorological mast, FINO3, in the North Sea, wind speed observations were integrated into the model core. The performance of this modified model was then assessed for three different atmospheric stability conditions. Results from this study, illustrate that for all three stratification cases, there is a significant improvement in model performance when using observational nudging showing a reduction in Root Mean Square Error of up to 27% when compared to the observations from FINO1 platform. This study suggests that observational nudging takes a step towards more accurate simulations in wind resource assessment (WRA).

Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to... more Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to onshore, offshore wind farms require larger installation and incur higher O&M costs due to the challenges of the marine environment. In this context condition monitoring systems have an important role to play in reducing maintenance costs. The high initial cost of condition monitoring systems motivates this analysis of the cost effectiveness of such technology O&M cost data are commercially sensitive and generally protected by the wind industry, especially for offshore operations. Component failure rates are essential for modelling wind turbine O&M costs but very little offshore failure rate data available in the public domain. With cooperation of the operator of the largest onshore wind farm in the UK and that of a large Swedish offshore wind farm, three years of operational data records have been made available for this research. With wind and wave parameters extracted from the databa...

The invention relates to the treatment against corrosion of a hollow metal structure containing a... more The invention relates to the treatment against corrosion of a hollow metal structure containing an aqueous medium, and is provided for this purpose: - a supply reservoir metal hydroxide in the structure (10), - an energy generator electrical (G) for promoting an oxidation-reduction reaction in which metal ions react with the carbonate from the aqueous medium to form a layer of metal carbonate, protective against corrosion on an inner wall of the structure acting to electrode in the oxidation-reduction reaction, and in that the device further comprises: - at least one sensor (13, 11) for measuring at least one parameter of the aqueous medium connected to a control module (12) of the generator (G) and / or an opening member (VA) of the reservoir (10) for, based on the measurement of said parameter, applying an additional supply of metal hydroxide in the medium and / or apply a greater contribution plementary into electrical energy.

The cost effectiveness of condition monitoring systems for offshore wind energy is uncertain and ... more The cost effectiveness of condition monitoring systems for offshore wind energy is uncertain and thus a research concern. Unlike onshore wind turbines, the O&M costs of offshore wind turbines are directly affected by the marine environment, mainly wind and wave conditions, and vessel costs are a main contributor to offshore O&M costs. The lack of offshore O&M data makes wind turbine component failure rates essential for component risk assessment and cost model design. However, the failure rate data, especially from the offshore turbines, are highly protected by the manufacturers and the offshore operators. The method developed in this paper deals with this lack of data by adjusting onshore failure rate data to offshore to account for the different operational conditions. Internal cooperation of a large onshore wind farm in the UK and a large Swedish offshore wind farm has been reached, and three-year-period operational data records are used for this research. Both the sites use Siem...

Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind... more Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind Farm (OWF) project lifecycle expenditure according to a range of studies. In this respect, identifying factors affecting operational costs and availability are vital for wind farm operators to achieve the most profitable decisions. Many OWFs are built in stages and the important factors may not be consistent for the different phases. To address this issue, three OWF case studies are defined to represent two phases and a complete project. An initial qualitative screening sensitivity analysis was conducted to identify the most important factors of O&M affecting operating cost and availability. The study concluded that the important factors for total O&M cost were access and repair costs along with failure rates for both minor and major repairs. For time-based availability, the important factors identified were those related to the length of time conducting the maintenance tasks, i.e. the ...

Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind... more Operation and Maintenance (O&M) costs are estimated to account for 14%e30% of total Offshore Wind Farm (OWF) project lifecycle expenditure according to a range of studies. In this respect, identifying factors affecting operational costs and availability are vital for wind farm operators to achieve the most profitable decisions. Many OWFs are built in stages and the important factors may not be consistent for the different phases. To address this issue, three OWF case studies are defined to represent two phases and a complete project. An initial qualitative screening sensitivity analysis was conducted to identify the most important factors of O&M affecting operating cost and availability. The study concluded that the important factors for total O&M cost were access and repair costs along with failure rates for both minor and major repairs. For time-based availability, the important factors identified were those related to the length of time conducting the maintenance tasks, i.e. the ...

Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to... more Offshore wind energy is a fast growing technology within the marine energy sector. In contrast to onshore, offshore wind farms require larger installation and incur higher O&M costs due to the challenges of the marine environment. In this context condition monitoring systems have an important role to play in reducing maintenance costs. The high initial cost of condition monitoring systems motivates this analysis of the cost effectiveness of such technology O&M cost data are commercially sensitive and generally protected by the wind industry, especially for offshore operations. Component failure rates are essential for modelling wind turbine O&M costs but very little offshore failure rate data available in the public domain. With cooperation of the operator of the largest onshore wind farm in the UK and that of a large Swedish offshore wind farm, three years of operational data records have been made available for this research. With wind and wave parameters extracted from the database and set as inputs to a cost model is has been possible to compare the O&M cost of reactive maintenance with condition based maintenance. The cost model available uses empirical failure rate based on onshore data and so will not fully represent the offshore situation as failure rates are expected to affected by offshore operational conditions. To overcome this limitation, a mathematical translation of failure rate from onshore to offshore is applied to the operational data. The way this translation is calculated is sensitive to the way the relevant probability distributions are represented and improved curve fitting approaches have been explored.

The method involves operating a low pressure compressor (1) and a high pressure compressor (2) at... more The method involves operating a low pressure compressor (1) and a high pressure compressor (2) at rotational speeds lower than nominal speeds of the compressors, where the rotational speed of the high pressure compressor is higher than the rotational speed of the low pressure compressor. The high pressure compressor maintains the rotational speed to be higher than that of the lower pressure compressor during acceleration or deceleration of the rotational speeds. An independent claim is also included for a thermodynamic device comprising a low pressure compressor.

Volume 6: Ocean Space Utilization; Ocean Renewable Energy, 2016

This article explores the application of a binary genetic algorithm and a binary particle swarm o... more This article explores the application of a binary genetic algorithm and a binary particle swarm optimizer to the optimization of an offshore wind farm layout. The framework developed as part of this work makes use of a modular design to include a detailed assessment of a wind farm’s layout including validated analytic wake modeling, cost assessment, and the design of the necessary electrical infrastructure considering constraints. This study has found that both algorithms are capable of optimizing wind farm layouts with respect to levelized cost of energy when using a detailed, complex evaluation function. Both are also capable of identifying layouts with lower levelized costs of energy than similar studies that have been published in the past and are therefore both applicable to this problem. The performance of both algorithms has highlighted that both should be further tuned and benchmarked in order to better characterize their performance.

Ocean Engineering, 2017

This article explores the application of a wind farm layout evaluation function and layout optimi... more This article explores the application of a wind farm layout evaluation function and layout optimization framework to Middelgrunden wind farm in Denmark. This framework has been built considering the interests of wind farm developers in order to aid in the planning of future offshore wind farms using the UK Round 3 wind farms as a point of reference to calibrate the model. The present work applies the developed evaluation tool to estimate the cost, energy production, and the levelized cost of energy for the existing as-built layout at Middelgrunden wind farm; comparing these against the cost and energy production reported by the wind farm operator. From here, new layouts have then been designed using either a genetic algorithm or a particle swarm optimizer. This study has found that both optimization algorithms are capable of identifying layouts with reduced levelized cost of energy compared to the existing layout while still considering the specific conditions and constraints at this site and those typical of future projects. Reductions in levelized cost of energy such as this can result in significant savings over the lifetime of the project thereby highlighting the need for including new advanced methods to wind farm layout design.

In existing houses equipped with hydronic networks and radiators, the supply water temperature ca... more In existing houses equipped with hydronic networks and radiators, the supply water temperature can exceed 65°C the coldest days to ensure required comfort conditions. So to replace old boilers by heat pumps, it is necessary that the heat pumps produce water at high temperature the coldest days. In order to analyze their behavior and measure their performances, field-test has been carried out in France on air to water heat pump designed to replace fuel boilers. The results of the field-test has allowed expressing the thermal energy produced and the electrical energy consumed by the heat pump as a function of the average daily outdoor air temperature. So it is possible with weather data of different climate areas to calculate the thermal and electrical energies and so estimate the Heating Seasonal Performance Factor.

Renewable Energies Offshore, 2015

Failure Modes Effect Analysis (FMEA), or more specifically, Failure Modes Effect and Criticality ... more Failure Modes Effect Analysis (FMEA), or more specifically, Failure Modes Effect and Criticality Analysis (FMECA) has been accepted as an effective condition monitoring assessment tool used widely by the mili-tary, traditional industries and reliability relevant engineering systems. A successful FMEA assists to identity, evaluate and report component failure modes, their severity and impact on the systems. FMEA has been al-ready applied to onshore wind turbines, but there is a lack of offshore wind turbine applications. FMEA can be quantified by using the metric of Risk Priority Number (RPN), defined as the product of the levels of event severity, occurrence frequency and detectability. This paper presents an approach that allows the application of RPN to offshore wind energy by identifying correction factors to existing onshore RPN values taken from previous research. This approach estimates offshore failure rates for key wind turbine components from onshore data.