Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET (original) (raw)

Learning Materials by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

Energetics, radioactive decay, fission, fusion, reaction rates, power © 2013 Dr Zeina Rahal. Pe... more Energetics, radioactive decay, fission, fusion, reaction rates, power
© 2013 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying, hiring, lending is prohibited.

Energy content, Temporal variation, 2013

© 2013 © 2015 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial ... more © 2013 © 2015 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying, hiring, lending is prohibited.

Wind Speed Characteristics, Resource Assessment, Energy Production Potential , 2013

© 2013 © 2017 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial c... more © 2013 © 2017 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying, hiring, lending is prohibited.

Blade forces, Betz limit, 2013

© 2013 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying,... more © 2013 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying, hiring, lending is prohibited.

© 2012 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying,... more © 2012 Dr Zeina Rahal. Permission granted to reproduce for personal use only. Commercial copying, hiring, lending is prohibited.

Assessments by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

© 2017 Dr Zeina Rahal. Permission granted to reproduce for personal and educational use only. Com... more © 2017 Dr Zeina Rahal. Permission granted to reproduce for personal and educational use only. Commercial copying, hiring, lending is prohibited.

Research Portfolio by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

Journal Papers by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

Desalination and Water Treatment , 2009

The specific energy consumption (SEC) of pressure-driven liquid-phase membrane processes, in part... more The specific energy consumption (SEC) of pressure-driven liquid-phase membrane processes, in particular the reverse osmosis (RO) process, has usually been estimated using a phenomenological approach, which does not explicitly consider the membrane properties and operating parameters. This paper presents a new analytical approach that has been derived, from a well-established theory, to estimate the SEC and to quantify the effect of membrane properties; namely, membrane per- meability and surface area as well as the effect of process parameters such as feed pressure, recovery rate, membrane element permeate rate, and feed osmotic pressure. The SEC is also presented in terms of a dimensionless parameter, namely, the specific energy indicator (SEI), which can be used as a membrane property to indicate the SEC of the membrane element for a given process recovery rate and feed osmotic pressure. The SEC calculations are presented for desalting a NaCl solution with a salinity of 35,000 mg/L over a wide range of recovery rates and membrane element permeate flow rates. The calculations showed that for a membrane element with a permeate flow rate of 2 m3/h operating at 50% system recovery rate, the SEC of the RO process can be reduced by more than 35% if the membrane element flow rate factor is doubled, for example, from a value of 20 to 40 L/h.bar.

Journal of Water Reuse and Desalination , 2003

Reverse osmosis plants for seawater (SWRO) function best under constant load and a steady and opt... more Reverse osmosis plants for seawater (SWRO) function best under constant load and a steady and optimal flow and pressure, and wind power with its instantaneous variability would not seem to be a useful source of energy for RO. However, the paper describes a novel plant design for this process in which a wind turbine is used to drive a state-of-the art variable capacity hydraulic drive, which is linked to an integrated hydraulic pressure deintensifier, energy storage, and brine pressure energy recovery system. The proposed design was modelled and the effect of temporal variations in power from the wind turbine on a time scale of the order of 1s was studied. It is claimed that the plant would be economically more favourable than existing designs, and could be competitive in regions with a favourable wind resource.

Magazine Articles by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

Arab Water World (AWW), 2010

Conference Papers by Dr Zeina Rahal - BE, MSc (Dist), PhD, MIET

World Renewable Energy Congress, 2011

This paper presents a study on the potential of osmotic energy for power production. The study in... more This paper presents a study on the potential of osmotic energy for power production. The study includes both pilot plant testing and theoretical modelling including cost estimation. A projected cost of 30 $/MWh of clean electricity could be achieved by using a Hydro-Osmotic Power (HOP) plant if a suitable membrane is used and the osmotic potential difference between the two solutions is greater than 25 bar; a condition that can be achieved in a number of ways.
Results have shown that the membrane system account for 50% - 80% of the HOP plant cost depending on the osmotic pressure difference level. Thus, further development in membrane technology and identifying suitable membranes would have significant impact on the feasibility of the process and the route to market. The results have shown the strong dependency of the produced power cost on the membrane permeability. The results have also shown that a substantial reduction in the membrane area requirment for a given power output can be achieved as the osmotic pressure difference between the two solutions increases beyond 50 bar.

International Desalination Association Congress, 2009

Grove Fuel Cell Symposium, London, UK, 2005

European Wind Energy Conference, 2002

Energy content, Temporal variation, 2013

Wind Speed Characteristics, Resource Assessment, Energy Production Potential , 2013

Blade forces, Betz limit, 2013

Desalination and Water Treatment , 2009

Journal of Water Reuse and Desalination , 2003

World Renewable Energy Congress, 2011

International Desalination Association Congress, 2009

Grove Fuel Cell Symposium, London, UK, 2005

European Wind Energy Conference, 2002

Proceedings of the European Wind Energy Conference, 1997

Proceedings of the British Wind Energy Conference, 1997

This thesis investigates the technical problems associated with large-scale stand-alone wind powe... more This thesis investigates the technical problems associated with large-scale stand-alone wind powered desalination employing a short-term energy store, particularly the complexities associated with the intermittent operation of the desalination plant. To achieve this, a non-linear, time domain system model of an existing wind powered desalination plant has been developed using the propriety code Simulink. Two desalination techniques have been considered: reverse osmosis and electrodialysis, due firstly to their relatively low specific energy consumption, and secondly, their efficient coupling to a wind turbine generator. As a way of reducing power mismatch, optimising water production, and above all reducing the switching rates of the desalination units, operation of the reverse osmosis and electrodialysis units under variable power conditions is suggested. Little information is available on plant performance under such conditions. A mathematical model has therefore been developed to ascertain the performance of reverse osmosis and electrodialysis processes under transient power conditions. The model consists of the set of partial differential equations (PDEs) describing the conservation of mass, momentum and chemical species coupled with the appropriate boundary conditions. A numerical solution based on the finite volume method has been employed to solve for the system of PDEs, as no analytical solution is available for the particular set of model equations derived. Sensitivity of plant performance to key design parameters (such as operating pressure and energy storage capacity) and operational strategies is predicted from simulation results. This technology is economically attractive for islands where wind energy density is high and water resources are scarce.

Report of the Rail Research UK (RRUK) Funded Project C4/1 - First published on RRUK website, 2005

A wide range of technologies and alternative fuels could potentially be introduced
into rail. A subset of these was analysed for the present study, including the use of both proton exchange membrane and solid oxide fuel cells as prime movers, hybridisation with energy storage, and fuels such as natural gas, biofuels and hydrogen. Base case diesel and overhead electrified data were also considered.
Modelling was conducted using rail-specific duty cycles for intercity passenger transport, urban commuting, and freight.

The modelling suggests that hybridisation of diesel engines provides an improvement
in energy efficiency of up to 10-20% for passenger trains, and hence a reduction in CO2
emissions. Freight efficiency was unaffected due to its already flat load curve. The use of PEM hybrid systems also offers advantages, with the primary benefit being realised for high speed and freight trains, at around 25% reduction. Urban cycles with fuel cells sized to meet peak load were found to be more efficient than those sized to meet mean load, but this translates into larger and more expensive fuel cells. SOFC in the configuration modelled offered limited advantages in terms of on-board efficiency.
The degree of hybridisation and the maximum recoverable braking energy are key parameters in the analysis. High braking energy recovery and reuse would be ideal, but is typically both costly and heavy, and so for the majority of the analysis 30% is considered reasonable.

In order to put the figures for improvements possible through a change or modification in prime mover into context, the cost and CO 2 emissions from drive cycles were also considered.

Costs of introduction of the different chains were estimated from known data, given that many new technologies have not reached cost maturity. Emissions from drive cycles were calculated using the specific energy figures modelled in the initial analysis, and efficiency figures from fuel chains found in literature. By introducing the full fuel cycle as part of the analysis, the efficiency of fuel provision can be balanced against the efficiency of use.
The model shows that significant reductions in specific CO 2 emissions can be
achieved using different fuel chains in conjunction with the new technologies.
In comparison with a diesel ICE base case, emissions can be reduced by as much as ~80% under different scenarios. Hybridisation, electrification and the use of fuel cells all offer promising benefits. However, many of these options offer significant increases in cost for the near term, of up to 30%. Only as mass-production takes place do these costs come below current technology.
Many of the options do offer major reductions in CO2 emissions, with biodiesel, electrification and fuel cells showing potential reductions of at least 60% and approaching 80%.
Using the results calculated, rail compares very favourably with other modes of passenger and freight transport.
This study has been conducted over a short time frame and with very limited resources. It shows that the introduction of new technologies into rail could significantly improve its environmental performance, sometimes with only small cost penalties. As CO2 emissions from every source become more tightly controlled, and energy prices rise, the introduction of these new technologies will make increasing commercial sense. Further, more sophisticated analysis into these fuel chains and technologies would provide the robust data needed to allow the rail industry to make informed decisions about implementing these new technologies and maintaining the current advantage over competing transport modes.

EPSRC GR/R94909/01 Wind Energy for Thermal Processing: a Feasibility Study

EC Contract JOR3-CT95-0077, Seawater Desalination by an Autonomous Wind Energy System (SDAWES)

Rail offers advantages in terms of environmental performance in comparison with many other modes ... more Rail offers advantages in terms of environmental performance in comparison with many other modes of transport. However, as alternatives such as air and road transport improve and new technologies are introduced, the advantages are reduced. To maintain or increase them, new technologies and systems will also have to be introduced in the railways. Railway Research UK, an EPSRC-funded research centre, has provided funding to a team comprising groups within Loughborough University and Imperial College London, to conduct preliminary analysis on some of the possible future power and fuel combinations with regard to their economic and environmental characteristics. A wide range of technologies and alternative fuels could potentially be introduced into rail. A subset of these was analysed for the present study, including the use of both proton exchange membrane and solid oxide fuel cells as prime movers, hybridisation with energy storage, and fuels such as natural gas, biofuels and hydrogen. Base case diesel and overhead electrified data were also considered. Modelling was conducted using rail-specific duty cycles for intercity passenger transport, urban commuting, and freight. The modelling suggests that hybridisation of diesel engines provides an improvement in energy efficiency of up to 10-20% for passenger trains, and hence a reduction in CO2 emissions. Freight efficiency was unaffected due to its already flat load curve. The use of PEM hybrid systems also offers advantages, with the primary benefit being realised for high speed and freight trains, at around 25% reduction. Urban cycles with fuel cells sized to meet peak load were found to be more efficient than those sized to meet mean load, but this translates into larger and more expensive fuel cells. SOFC in the configuration modelled offered limited advantages in terms of on-board efficiency. The degree of hybridisation and the maximum recoverable braking energy are key parameters in the analysis. High braking energy recovery and reuse would be ideal, but is typically both costly and heavy, and so for the majority of the analysis 30% is considered reasonable. In order to put the figures for improvements possible through a change or modification in prime mover into context, the cost and CO 2 emissions from drive cycles were also considered. Costs of introduction of the different chains were estimated from known data, given that many new technologies have not reached cost maturity. Emissions from drive cycles were calculated using the specific energy figures modelled in the initial analysis, and efficiency figures from fuel chains found in literature. By introducing the full fuel cycle as part of the analysis, the efficiency of fuel provision can be balanced against the efficiency of use. The model shows that significant reductions in specific CO 2 emissions can be achieved using different fuel chains in conjunction with the new technologies. In comparison with a diesel ICE base case, emissions can be reduced by as much as ~80% under different scenarios. Hybridisation, electrification and the use of fuel cells all offer promising benefits. However, many of these options offer significant increases in cost for the near term, of up to 30%. Only as mass-production takes place do these costs come below current technology. Many of the options do offer major reductions in CO2 emissions, with biodiesel, electrification and fuel cells showing potential reductions of at least 60% and approaching 80%. Using the results calculated, rail compares very favourably with other modes of passenger and freight transport. This study has been conducted over a short time frame and with very limited resources. It shows that the introduction of new technologies into rail could significantly improve its environmental performance, sometimes with only small cost penalties. As CO2 emissions from every source become more tightly controlled, and energy prices rise, the introduction of these new technologies will make increasing commercial sense. Further, more sophisticated analysis into these fuel chains and technologies would provide the robust data needed to allow the rail industry to make informed decisions about implementing these new technologies and maintaining the current advantage over competing transport modes.

Journal of Water Reuse and Desalination, 2003

Desalination and Water Treatment, 2009

Proceedings of the World Renewable Energy Congress – Sweden, 8–13 May, 2011, Linköping, Sweden, 2011