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Papers by Anthony P Roskilly

Proceedings of the International Symposium on Mechanical Engineering and Material Science, 2016

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 Unported License New... more This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 Unported License Newcastle University ePrints-eprint.ncl.ac.uk

Organic Rankine Cycle Technology for Heat Recovery, Nov 7, 2018

The development of engine waste heat recovery (WHR) technologies attracts ever increasing interes... more The development of engine waste heat recovery (WHR) technologies attracts ever increasing interests due to the rising strict policy requirements and environmental concerns. Organic Rankine Cycle (ORC) can convert low medium grade heat into electrical or mechanical power and has been widely recognized as the most promising heat-driven technologies. A typical internal combustion engine (ICE) converts around 30% of the overall fuel energy into effective mechanical power and the rest of fuel energy is dumped through the engine exhaust system and cooling system. Integrating a well-designed ORC system to ICE can effectively improve the overall energy efficiency and reduce emissions with around 2-5 years payback period through fuel saving. This book chapter is meant to provide an overview of the technical development and application of ORC technology to recover wasted thermal energy from the ICE with a particular focus on vehicle applications.

Energies, 2019

There are few experimental reports combining hybrid energy storage and diesel engine generators a... more There are few experimental reports combining hybrid energy storage and diesel engine generators as the power source of distributed power generation systems. In this article, a distributed power generation with energy storage system (DG-ES) which contains a diesel engine generator and an energy storage unit is set up and tested in the laboratory to satisfy the dynamic changing load. The hybrid energy storage system is composed of a lead-acid battery and a supercapacitor. The DG-ES supplied power to meet the domestic load demand successfully under different seasons. A simulation model of this system was also set up in MATLAB software used to guide to the experimental operation of this system. The simulation results has 2.69% and 2.35% error. The results of the experimental tests show the DG-ES can provide enough power to meet the dynamic loads of the selected house, especially at peak time in both winter and summer time. Computational simulation results show that the performance of DG...

Energy Conversion and Management: X, 2020

(2020) 'The impact of disruptive powertrain technologies on energy consumption and carbon dioxide... more (2020) 'The impact of disruptive powertrain technologies on energy consumption and carbon dioxide emissions from heavy-duty vehicles.', Energy conversion and management x., 6. p. 100030.

Applied Energy, 2017

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Intern... more This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints-eprint.ncl.ac.uk Chen XP, Hewitt N, Li ZT, Wu QM, Yuan X, Roskilly T. Dynamic programming for optimal operation of a biofuel micro CHP-HES system.

Energies, 2019

Over 90% of global yam production is from West Africa where it provides food and income for above... more Over 90% of global yam production is from West Africa where it provides food and income for above 300 million smallholders’ farmers. However, the major challenge of yam is 10–40% post-harvest losses due to the lack of appropriate storage facilities. This paper assesses a biogas-driven cogeneration system, which could supply electricity and cold storage for ‘yam bank’ within a rural community. Considering 200 households’ Nigerian village as a case study, crop residues are used as anaerobic digestion feedstock to produce biogas, which is subsequently used to power an internal combustion engine. Result shows that the system could store 3.6 tonnes of yam tubers each year and provide enough electricity for domestic and commercial activities. At the current electricity tariff of USD0.013·kWh−1 for rural areas, the system is unable to payback during its life span. The proposed USD0.42·kWh−1 by Nigerian Rural Electrification Agency seems good with less than 3 years discounted payback period...

Energies, 2019

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper... more Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is impro...

Energy Procedia, 2017

District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Applied Energy, 2018

Tony (2018) 'Eect of carbon coated aluminum nanoparticles as additive to biodiesel-diesel blends ... more Tony (2018) 'Eect of carbon coated aluminum nanoparticles as additive to biodiesel-diesel blends on performance and emission characteristics of diesel engine.', Applied energy., 221. pp. 597-604.

Energies, 2017

Thermal Overload' can be defined as a condition under which design threshold values such as the s... more Thermal Overload' can be defined as a condition under which design threshold values such as the surface temperature of combustion chamber components is exceeded. In this paper, a low λ value is identified as the most probable cause of voluminous flame production, resulting in high surface temperatures of engine components, i.e., engine thermal overload. Test results indicated that the flame became voluminous when the excess air ratio, λ was low, and the exhaust temperature increased from 775 to 1000 • C with λ changing from 1.12 to 0.71. Temperature indicating paints were applied on two piston crowns to investigate the effect of the voluminous flame on component surface temperature. The piston crown with high rates of hot corrosion was very close to matt glaze (much in excess of the design temperature), which proved that high surface temperature and salt deposition on the crown in the heavily burned away regions could have been caused by flame and fuel impingement, respectively. A numerical calculation was presented to estimate the flame temperature for various air excess ratio, which provides a guidance for the operation conditions of diesel engines to avoid engine thermal fatigue due to thermal overload.

Energy, 2014

A novel integration of chemisorption refrigeration cycle and a scroll expander was investigated f... more A novel integration of chemisorption refrigeration cycle and a scroll expander was investigated for the cogeneration of cooling and electric power. The first lab prototype machine has been built, and the two main components were tested both independently and cooperatively for comparison before and after the integration therefore leading to better knowledge of the interaction between them. Two sets of adsorption cycles utilizing the adsorbent compound of calcium chloride and activated carbon worked out-of-phase for the output continuity, and mass recovery was applied to further elevate the performance. In the cogeneration test, the cooling temperature reached 5.4 C as minimum, while the generated electric power achieved the maximum value of 490 W. The valuable experience and the inspiration on system optimization has been reaped and discussed through this exploration.

Advanced Materials Research, 2012

As a crucial constituent in tri-generation application, electric energy storage and power system ... more As a crucial constituent in tri-generation application, electric energy storage and power system plays an important role regarding efficient utilization of electrical energy in tri-generation. This paper presents the results showing that the optimization of electrical energy storage is able to promote the performance of tri-generation. Initial investigation, including laboratory tests and computational simulation using Dymola software, have been carried out. A case study exemplifies how diverse hybrid systems accommodate domestic power demands. The outcomes validate that the hybrid electric system consisting of generator, batteries and super capacitor can satisfy the electricity requirements for the household. it is also found that the hybrid system can supply the peak electricity demands where the integration of super capacitor can alleviate the overcharge of batteries in this application.

Interface Focus, 2012

According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the ... more According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the population in Africa, some 587 million people, mostly in sub-Saharan Africa, lacked access to electricity in 2009. We developed a 6.5 kWe micro-trigeneration prototype, on the basis of internal combustion engine with pure Croton megalocarpus oil (CMO) fuelling, which configures a distributed energy system to generate power, heating and cooling from a single sustainable fuel source for remote users. Croton megalocarpus is an indigenous tree in East and South Africa which has recently attracted lots of interests as a biofuel source because of its high oil-yield rate. The direct and local use of CMO, instead of CMO biodiesel converted by the transesterification process, minimizes the carbon footprints left behind because of the simple fuel production of CMO. The experimental assessment proves that the prototype fuelled with CMO achieves similar efficiency as with diesel. Also, with the elev...

Energy Procedia, 2014

In the present paper the combustion behaviour and soot generation of different neat vegetable oil... more In the present paper the combustion behaviour and soot generation of different neat vegetable oils on a direct injection optical diesel engine have been investigated using in-cylinder pressure based combustion analysis and high-speed two colour method. A singlecylinder optical diesel engine with an electronically controlled common-rail fuel injection system has been used for this study. Four different vegetable oils, Jatropha, Croton, Rapeseed and Sunflower oil, have been tested at 120 MPa injection pressure and fuel temperatures of 60 and 90 C. All tests were performed at fixed injection timings and fixed engine speed at 1200 rev/min with pilot and main injection. The experimental results show that although all four bio-oils have very similar physiochemical properties, some differences in their combustion and soot generation behaviour have been observed. It was concluded that sunflower oil (SFO) had very good combustion properties at lower temperatures compared to other fuels. While croton oil (CO) did not have outstanding combustion behaviour at any conditions, the combustion of Jatropha oil (JO) was improved at higher fuel injection temperatures.

Energy Procedia, 2014

Modelling and simulation have vital roles in accelerating research, providing a more effective wa... more Modelling and simulation have vital roles in accelerating research, providing a more effective way to predict processes without the need to perform specific experimental tests. This study investigated the potential of using raw oil from microalgal biomass as a direct substitute fuel in an internal combustion engine. Based on the fuel properties of the algal oil, the performance and emission characteristics of a diesel engine running with this fuel were investigated using the software «Diesel-RK». The results were compared with croton oil as this provides a useful foundation for comparing this new fuel with other biooils and diesel fuels. Algal oil demonstrated lower engine power output and NO x emissions compared to croton oil, whereas at the same time it showed higher break specific fuel consumption, particulate matter and CO 2 emissions.

Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2009

This article investigates the in-cylinder heat transfer losses of a free-piston diesel engine and... more This article investigates the in-cylinder heat transfer losses of a free-piston diesel engine and compares the results with those of a conventional engine, using a multidimensional simulation model. In-cylinder heat transfer, fuel efficiency, and nitrogen oxides (NO) emissions formation are studied, along with the suitability of the free-piston engine to use a low heat rejection combustion chamber design. It is found that the high piston acceleration around top dead centre and the fast power stroke expansion in the free-piston engine lead to reduced heat transfer losses and reduced NO emissions formation, the latter in the order of 17 per cent compared with conventional engines. Even for highly insulated combustion chambers, the free-piston engine is predicted to have lower NO emissions than the conventional engine in the original configuration. The use of a low heat rejection combustion chamber is found to benefit engine fuel efficiency in both free-piston and conventional engines,...

International Journal of Hydrogen Energy, 2008

This paper presents the findings of an experimental investigation into the operation of a compres... more This paper presents the findings of an experimental investigation into the operation of a compression ignition (CI) engine in homogeneous charge compression ignition (HCCI) mode using hydrogen fuel. Factors that were investigated include engine efficiency, emissions and mechanical loads. Hydrogen was found to be a possible fuel for operation of a CI engine in HCCI mode. The heat release rate is extremely high, which leads to high ignition timing control requirements. The ignition timing was controlled using heating of the inlet air, and satisfactory performance was demonstrated using this method. Some cycle-to-cycle variations were, however, observed due to the difficulty in achieving accurate control of ignition timing. Use of hydrogen in HCCI engines allows operation with very lean air-fuel mixtures, giving extremely low emissions of nitrogen oxides and other pollutants. Operation with an excess air ratio of 6 was demonstrated, and a maximum fuel efficiency of 45% was achieved with an excess air ratio of 3. The maximum power of the engine in HCCI mode is, however, quite modest, being limited by the need for inlet air heating to ensure auto ignition, which reduces the air mass flow through the engine. There are also mechanical limitations to the operation of the HCCI hydrogen engine at high loads due to higher rates of pressure rise and in-cylinder peak pressures compared to conventional diesel mode.

International Journal of Hydrogen Energy, 2009

This paper describes the development of an experimental setup for the testing of a diesel engine ... more This paper describes the development of an experimental setup for the testing of a diesel engine in direct injection hydrogen-fuelled mode. Test results showed that the use of hydrogen direct injection in a diesel engine gave a higher power to weight ratio when compared to conventional diesel-fuelled operation, with the peak power being approximately 14% higher. The use of inlet air heating was required for the hydrogen-fuelled engine to ensure satisfactory combustion, and a large increase in the peak in-cylinder gas pressure was observed. A significant efficiency advantage was found when using hydrogen as opposed to diesel fuel, with the hydrogen-fuelled engine achieving a fuel efficiency of approximately 43% compared to 28% in conventional, diesel-fuelled mode. A reduction in nitrogen oxides emissions formation of approximately 20% was further observed.

International Journal of Energy Research, 2014

For power generation systems, the expansion machine is one of the most crucial components. In thi... more For power generation systems, the expansion machine is one of the most crucial components. In this work, a scroll expander test rig has been constructed and tested to simulate the performance in a resorption cogeneration under similar working conditions. The relationship between the inlet pressure and the volume flow rate has been experimentally achieved and the volume ratio is around 2.80 under the tested conditions. A minimum start state to generate electricity from the scroll expander has been investigated, which is at least 145kPa. The isentropic efficiency of the scroll expander is around 0.6. Meanwhile the electrical efficiency achieved by this system is around 0.35 and 0.40 under the supply pressure at 238.0 kPa and 333.5 kPa, respectively.

Fuel Processing Technology, 2010

An experimental study of the performances and emissions of a diesel engine is carried out using t... more An experimental study of the performances and emissions of a diesel engine is carried out using two different biodiesels derived from Chinese pistache oil and jatropha oil compared with pure diesel. The results show that the diesel engine works well and the power outputs are stable running with the two selected biodiesels at different loads and speeds. The brake thermal

Proceedings of the International Symposium on Mechanical Engineering and Material Science, 2016

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 Unported License New... more This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 Unported License Newcastle University ePrints-eprint.ncl.ac.uk

Organic Rankine Cycle Technology for Heat Recovery, Nov 7, 2018

The development of engine waste heat recovery (WHR) technologies attracts ever increasing interes... more The development of engine waste heat recovery (WHR) technologies attracts ever increasing interests due to the rising strict policy requirements and environmental concerns. Organic Rankine Cycle (ORC) can convert low medium grade heat into electrical or mechanical power and has been widely recognized as the most promising heat-driven technologies. A typical internal combustion engine (ICE) converts around 30% of the overall fuel energy into effective mechanical power and the rest of fuel energy is dumped through the engine exhaust system and cooling system. Integrating a well-designed ORC system to ICE can effectively improve the overall energy efficiency and reduce emissions with around 2-5 years payback period through fuel saving. This book chapter is meant to provide an overview of the technical development and application of ORC technology to recover wasted thermal energy from the ICE with a particular focus on vehicle applications.

Energies, 2019

There are few experimental reports combining hybrid energy storage and diesel engine generators a... more There are few experimental reports combining hybrid energy storage and diesel engine generators as the power source of distributed power generation systems. In this article, a distributed power generation with energy storage system (DG-ES) which contains a diesel engine generator and an energy storage unit is set up and tested in the laboratory to satisfy the dynamic changing load. The hybrid energy storage system is composed of a lead-acid battery and a supercapacitor. The DG-ES supplied power to meet the domestic load demand successfully under different seasons. A simulation model of this system was also set up in MATLAB software used to guide to the experimental operation of this system. The simulation results has 2.69% and 2.35% error. The results of the experimental tests show the DG-ES can provide enough power to meet the dynamic loads of the selected house, especially at peak time in both winter and summer time. Computational simulation results show that the performance of DG...

Energy Conversion and Management: X, 2020

(2020) 'The impact of disruptive powertrain technologies on energy consumption and carbon dioxide... more (2020) 'The impact of disruptive powertrain technologies on energy consumption and carbon dioxide emissions from heavy-duty vehicles.', Energy conversion and management x., 6. p. 100030.

Applied Energy, 2017

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Intern... more This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence Newcastle University ePrints-eprint.ncl.ac.uk Chen XP, Hewitt N, Li ZT, Wu QM, Yuan X, Roskilly T. Dynamic programming for optimal operation of a biofuel micro CHP-HES system.

Energies, 2019

Over 90% of global yam production is from West Africa where it provides food and income for above... more Over 90% of global yam production is from West Africa where it provides food and income for above 300 million smallholders’ farmers. However, the major challenge of yam is 10–40% post-harvest losses due to the lack of appropriate storage facilities. This paper assesses a biogas-driven cogeneration system, which could supply electricity and cold storage for ‘yam bank’ within a rural community. Considering 200 households’ Nigerian village as a case study, crop residues are used as anaerobic digestion feedstock to produce biogas, which is subsequently used to power an internal combustion engine. Result shows that the system could store 3.6 tonnes of yam tubers each year and provide enough electricity for domestic and commercial activities. At the current electricity tariff of USD0.013·kWh−1 for rural areas, the system is unable to payback during its life span. The proposed USD0.42·kWh−1 by Nigerian Rural Electrification Agency seems good with less than 3 years discounted payback period...

Energies, 2019

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper... more Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is impro...

Energy Procedia, 2017

District heating networks are commonly addressed in the literature as one of the most effective s... more District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

Applied Energy, 2018

Tony (2018) 'Eect of carbon coated aluminum nanoparticles as additive to biodiesel-diesel blends ... more Tony (2018) 'Eect of carbon coated aluminum nanoparticles as additive to biodiesel-diesel blends on performance and emission characteristics of diesel engine.', Applied energy., 221. pp. 597-604.

Energies, 2017

Thermal Overload' can be defined as a condition under which design threshold values such as the s... more Thermal Overload' can be defined as a condition under which design threshold values such as the surface temperature of combustion chamber components is exceeded. In this paper, a low λ value is identified as the most probable cause of voluminous flame production, resulting in high surface temperatures of engine components, i.e., engine thermal overload. Test results indicated that the flame became voluminous when the excess air ratio, λ was low, and the exhaust temperature increased from 775 to 1000 • C with λ changing from 1.12 to 0.71. Temperature indicating paints were applied on two piston crowns to investigate the effect of the voluminous flame on component surface temperature. The piston crown with high rates of hot corrosion was very close to matt glaze (much in excess of the design temperature), which proved that high surface temperature and salt deposition on the crown in the heavily burned away regions could have been caused by flame and fuel impingement, respectively. A numerical calculation was presented to estimate the flame temperature for various air excess ratio, which provides a guidance for the operation conditions of diesel engines to avoid engine thermal fatigue due to thermal overload.

Energy, 2014

A novel integration of chemisorption refrigeration cycle and a scroll expander was investigated f... more A novel integration of chemisorption refrigeration cycle and a scroll expander was investigated for the cogeneration of cooling and electric power. The first lab prototype machine has been built, and the two main components were tested both independently and cooperatively for comparison before and after the integration therefore leading to better knowledge of the interaction between them. Two sets of adsorption cycles utilizing the adsorbent compound of calcium chloride and activated carbon worked out-of-phase for the output continuity, and mass recovery was applied to further elevate the performance. In the cogeneration test, the cooling temperature reached 5.4 C as minimum, while the generated electric power achieved the maximum value of 490 W. The valuable experience and the inspiration on system optimization has been reaped and discussed through this exploration.

Advanced Materials Research, 2012

As a crucial constituent in tri-generation application, electric energy storage and power system ... more As a crucial constituent in tri-generation application, electric energy storage and power system plays an important role regarding efficient utilization of electrical energy in tri-generation. This paper presents the results showing that the optimization of electrical energy storage is able to promote the performance of tri-generation. Initial investigation, including laboratory tests and computational simulation using Dymola software, have been carried out. A case study exemplifies how diverse hybrid systems accommodate domestic power demands. The outcomes validate that the hybrid electric system consisting of generator, batteries and super capacitor can satisfy the electricity requirements for the household. it is also found that the hybrid system can supply the peak electricity demands where the integration of super capacitor can alleviate the overcharge of batteries in this application.

Interface Focus, 2012

According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the ... more According to the International Energy Agency's World Energy Outlook 2011, 60 per cent of the population in Africa, some 587 million people, mostly in sub-Saharan Africa, lacked access to electricity in 2009. We developed a 6.5 kWe micro-trigeneration prototype, on the basis of internal combustion engine with pure Croton megalocarpus oil (CMO) fuelling, which configures a distributed energy system to generate power, heating and cooling from a single sustainable fuel source for remote users. Croton megalocarpus is an indigenous tree in East and South Africa which has recently attracted lots of interests as a biofuel source because of its high oil-yield rate. The direct and local use of CMO, instead of CMO biodiesel converted by the transesterification process, minimizes the carbon footprints left behind because of the simple fuel production of CMO. The experimental assessment proves that the prototype fuelled with CMO achieves similar efficiency as with diesel. Also, with the elev...

Energy Procedia, 2014

In the present paper the combustion behaviour and soot generation of different neat vegetable oil... more In the present paper the combustion behaviour and soot generation of different neat vegetable oils on a direct injection optical diesel engine have been investigated using in-cylinder pressure based combustion analysis and high-speed two colour method. A singlecylinder optical diesel engine with an electronically controlled common-rail fuel injection system has been used for this study. Four different vegetable oils, Jatropha, Croton, Rapeseed and Sunflower oil, have been tested at 120 MPa injection pressure and fuel temperatures of 60 and 90 C. All tests were performed at fixed injection timings and fixed engine speed at 1200 rev/min with pilot and main injection. The experimental results show that although all four bio-oils have very similar physiochemical properties, some differences in their combustion and soot generation behaviour have been observed. It was concluded that sunflower oil (SFO) had very good combustion properties at lower temperatures compared to other fuels. While croton oil (CO) did not have outstanding combustion behaviour at any conditions, the combustion of Jatropha oil (JO) was improved at higher fuel injection temperatures.

Energy Procedia, 2014

Modelling and simulation have vital roles in accelerating research, providing a more effective wa... more Modelling and simulation have vital roles in accelerating research, providing a more effective way to predict processes without the need to perform specific experimental tests. This study investigated the potential of using raw oil from microalgal biomass as a direct substitute fuel in an internal combustion engine. Based on the fuel properties of the algal oil, the performance and emission characteristics of a diesel engine running with this fuel were investigated using the software «Diesel-RK». The results were compared with croton oil as this provides a useful foundation for comparing this new fuel with other biooils and diesel fuels. Algal oil demonstrated lower engine power output and NO x emissions compared to croton oil, whereas at the same time it showed higher break specific fuel consumption, particulate matter and CO 2 emissions.

Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2009

This article investigates the in-cylinder heat transfer losses of a free-piston diesel engine and... more This article investigates the in-cylinder heat transfer losses of a free-piston diesel engine and compares the results with those of a conventional engine, using a multidimensional simulation model. In-cylinder heat transfer, fuel efficiency, and nitrogen oxides (NO) emissions formation are studied, along with the suitability of the free-piston engine to use a low heat rejection combustion chamber design. It is found that the high piston acceleration around top dead centre and the fast power stroke expansion in the free-piston engine lead to reduced heat transfer losses and reduced NO emissions formation, the latter in the order of 17 per cent compared with conventional engines. Even for highly insulated combustion chambers, the free-piston engine is predicted to have lower NO emissions than the conventional engine in the original configuration. The use of a low heat rejection combustion chamber is found to benefit engine fuel efficiency in both free-piston and conventional engines,...

International Journal of Hydrogen Energy, 2008

This paper presents the findings of an experimental investigation into the operation of a compres... more This paper presents the findings of an experimental investigation into the operation of a compression ignition (CI) engine in homogeneous charge compression ignition (HCCI) mode using hydrogen fuel. Factors that were investigated include engine efficiency, emissions and mechanical loads. Hydrogen was found to be a possible fuel for operation of a CI engine in HCCI mode. The heat release rate is extremely high, which leads to high ignition timing control requirements. The ignition timing was controlled using heating of the inlet air, and satisfactory performance was demonstrated using this method. Some cycle-to-cycle variations were, however, observed due to the difficulty in achieving accurate control of ignition timing. Use of hydrogen in HCCI engines allows operation with very lean air-fuel mixtures, giving extremely low emissions of nitrogen oxides and other pollutants. Operation with an excess air ratio of 6 was demonstrated, and a maximum fuel efficiency of 45% was achieved with an excess air ratio of 3. The maximum power of the engine in HCCI mode is, however, quite modest, being limited by the need for inlet air heating to ensure auto ignition, which reduces the air mass flow through the engine. There are also mechanical limitations to the operation of the HCCI hydrogen engine at high loads due to higher rates of pressure rise and in-cylinder peak pressures compared to conventional diesel mode.

International Journal of Hydrogen Energy, 2009

This paper describes the development of an experimental setup for the testing of a diesel engine ... more This paper describes the development of an experimental setup for the testing of a diesel engine in direct injection hydrogen-fuelled mode. Test results showed that the use of hydrogen direct injection in a diesel engine gave a higher power to weight ratio when compared to conventional diesel-fuelled operation, with the peak power being approximately 14% higher. The use of inlet air heating was required for the hydrogen-fuelled engine to ensure satisfactory combustion, and a large increase in the peak in-cylinder gas pressure was observed. A significant efficiency advantage was found when using hydrogen as opposed to diesel fuel, with the hydrogen-fuelled engine achieving a fuel efficiency of approximately 43% compared to 28% in conventional, diesel-fuelled mode. A reduction in nitrogen oxides emissions formation of approximately 20% was further observed.

International Journal of Energy Research, 2014

For power generation systems, the expansion machine is one of the most crucial components. In thi... more For power generation systems, the expansion machine is one of the most crucial components. In this work, a scroll expander test rig has been constructed and tested to simulate the performance in a resorption cogeneration under similar working conditions. The relationship between the inlet pressure and the volume flow rate has been experimentally achieved and the volume ratio is around 2.80 under the tested conditions. A minimum start state to generate electricity from the scroll expander has been investigated, which is at least 145kPa. The isentropic efficiency of the scroll expander is around 0.6. Meanwhile the electrical efficiency achieved by this system is around 0.35 and 0.40 under the supply pressure at 238.0 kPa and 333.5 kPa, respectively.

Fuel Processing Technology, 2010

An experimental study of the performances and emissions of a diesel engine is carried out using t... more An experimental study of the performances and emissions of a diesel engine is carried out using two different biodiesels derived from Chinese pistache oil and jatropha oil compared with pure diesel. The results show that the diesel engine works well and the power outputs are stable running with the two selected biodiesels at different loads and speeds. The brake thermal