A student peer reviewed journal concerned with innovative analysis and assessment of advances in science and technology. Themed issues focus on Energy Science & Technology, Nanotechnology, Biotechnology, Life Science and Mathematics. Publications in PAM Review are expected to contribute new knowledge to respective disciplines. As such, the Journal provides students an authentic learning experience as researcher and author in a professional environment. This journal does not charge any type of article processing charge (APC) or any type of article submission charge. Established 2014 2014 Journal cover image courtesy US Department Of Energy. 2015 Journal cover image courtesy Wikimedia Commons - CC BY SA 3.0 2016 Journal cover image courtesy Asgeir Eggertsson at Wikimedia Commons - CC BY SA 3.0 2017 Journal cover image courtesy Leaflet - CC BY-SA 3.0 2018 Journal cover image courtesy H. Zell - Wikimedia Commons - CC BY-SA 3.0 2019 Journal cover image credit: Gorodenkoff: Astronaut in the Space Suit Works on Laptop, Adjusting Rover For Mars further Mars Exploration. Space Exploration Concept. First Manned Mission on Red Planet. (Stock image) 2020 Journal cover image credit: Thermoacoustic energy converter. Courtesy SoundEnergy B.V., Enschede, The Netherlands.
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Determining the best approach to commercial fusion power
This study sets out to determine which fusion power generator design is most suitable for centralised power production to be used commercially in communities comprising of domestic, corporate and industrial entities. We find there are currently only three main contenders in this field, those being the tokamak, the stellarator and the indirect-drive. Of these it is found that indirect-drive is too inefficient in comparison, though this is against theoretical numbers as the other systems are still under construction. We still are able to conclude that the stellarator is most likely to become the commercial power source.
This paper is a meta-study exploring the progression of nuclear fusion technology from a thermodynamic perspective. Thermodynamic parameters such as power, temperature, volume, efficiency and the fusion triple product (nTτ) were analysed in order to investigate the progress that has been achieved and the challenges that lay ahead. Nuclear fusion reactor designs, confinement systems, advantages and disadvantages are discussed herein. The findings conclude that there has been significant progress made in nuclear fusion research and development, to the point of being merely one order of magnitude away from commercial reactor conditions. It was also concluded that there is very little correlation between reactor volume and the current bench mark of fusion reactor performance, the fusion triple product.
Copyright note for this edition - CC BY 4.0
This is the first electronic publication of PAM Review: Energy Science & Technology. A hardcopy edition was published in 2014. This electronic first edition is published under a Creative Commons Attribution license (CC BY 4.0).
Clean and Sustainable Fusion Energy for the Future
Nuclear Fusion energy is one promising source of energy currently in the developmental stages with the potential to solve the world’s energy crisis by providing a clean and almost limitless supply of energy for the entire planet. This meta-study analyses the heating systems, cooling systems, energy output, heating power input, plasma volume, economic impact, plasma temperature, plasma density, plasma confinement time and Lawson’s Triple Product with respect to a variety of different nuclear fusion systems including the Wendelstein 7-X, the Helically Symmetric Stellarator Experiment, the ITER project, Joint European Torus, TFTR, IGNITOR and general information on tokamaks, stellarators as well as magnetic confinement of plasmas. Nuclear fusion is then more generally compared with four non-fusion energy sources, solar energy, wind energy, coal and hydroelectricity in terms of their overall economic impact, energy efficiency and environmental impact. Current global energy sources such as coal, oil and natural gas are briefly discussed with focus on their remaining global supply as well as their impact on the environment; this is contrasted with the remaining fuel supplies for nuclear fusion and fusion’s environmental impact. The result of this meta-study was that we found that fusion power is a long term solution to the energy crisis and so more of a focus needs to be placed globally on working to expand the use of hydroelectric power.
Efficiency Comparisons of Secondary Biofuels
Biofuels are essential for the energy production of the future. This report is a meta-study of the efficiencies of first, second and third generation secondary biofuels used for transportation purposes. We present and compare data from several studies concerning the efficiency of converting raw biomass info biofuels. We also compare this data to the efficiencies of hydrogen and solar power transportation systems. The efficiency data was presented as percentages from ratios of different data types, primarily exergy and energy efficiency ratios, which are defined for each study throughout the report. The highest efficiency percentages were displayed by second-generation wood knot rejects that did not require pretreatment input energy and resulted in high-energy ethanol output. The lowest efficiency percentages were from quasi-solar thermophotovoltaic radiator technology, heightening the reputation of biofuels as the efficient, renewable transportation energy source of tomorrow.
Review of the Deployment of and Research into Generation III & IV Nuclear Fission Reactors for Power Generation
Nuclear fission is one of the more popular and efficient sources of energy that has been used in the last few decades. In the setting of the ongoing worldwide debate of the energy problem, this paper will review the different types and generations of nuclear reactors, and do comparisons with other notable energy sources (biofuel and fusion). The current generations III, III+, IV of reactor (mostly pressurized water reactors), their thermal efficiency, technical (structure and configuration), lifetime, energy output and how the systems contrast are discussed. The paper was written by gathering information from UTS library online database, as well as online articles related to fission power, all sources dating from 2000s onwards. Nuclear fission power is a very dense energy source as it provides higher amount of free energy than other energy sources from the same amount of fuel. The drawback, which is the high amount of radioactive waste that accumulates over time, along with thermal efficiency are improved upon by the current and next generations of reactors.
Group Photograph of PAM Review Authors - 2014
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This is the second issue of PAM Review, the peer-reviewed, class specific student research journal of the School of Mathematical and Physical Sciences at the University of Technology Sydney. The student journal was first introduced into the subject Energy Science and Technology (68412) in 2014 to allow for a practical student centered, authentic learning experience that is exciting and challenging and helps to facilitate desired graduate outcomes. Energy, Science and Technology is a one-semester subject (class) that covers the thermodynamics of macroscopic and microscopic processes in the context of energy production, energy saving and related applications. This subject is open to students in science as well as engineering.
Copyright (c) 2015 PAM Review: Energy Science & Technology
An Analysis of the Effect of Molten Salt Thermal Storage on Parabolic Trough Concentrated Solar Power Plant Efficiency
In the development of renewable energy sources, there has been a trend toward increasing and stabilising the power output of Concentrated Solar Power Plants (CSPPs) during times of reduced solar resource through the use of Thermal Energy Storage Devices (TESDs). This study investigates whether the use of a molten salt TESD decreases the efficiency of a parabolic trough CSPP due to additional system energy losses despite prolonging the operational time of the CSPP. A theoretical analysis of a simplified CSPP was made to determine if a TESD would impact the efficiency of the CSPP. This was followed up by a survey of currently active parabolic trough CSPPs both with and without molten salt TESDs. The theoretical analysis illustrated that a TESD would have no effect on the efficiency of a CSPP. However, the survey revealed that the use of a TESD improved the efficiency of a CSPP. The results of the study don't support the theoretical analysis or the hypothesis suggesting that a property has been overlooked. This property is most likely to be that generators tend to operate best within a certain temperature range, and in a CSPP the optimum temperature range cannot be maintained. This results in a generator being selected capable of operating for the longest period with the lowest amount of excess solar energy. When a TESD is implemented, the excess solar energy is stored for later use, prolonging the generator's running time and increasing the useable energy. The realisation of the ability of a TESD to increase the efficiency of a CSPP as well as extending its operating time shows a promising area of development in CSPP technology and increasing its application in electricity generation.
Investigation of thermodynamic factors influencing Thorium reactor efficiencies
In this meta-study, the major forms of thorium based nuclear reactors were compared using thermodynamic parameters to find which reactor type holds the highest thermodynamic efficiency and hence, determine which reactor would be most beneficial to research further and implement for energy production. Our study found that molten salt reactors had the best thermodynamic efficiency and also runs at one atmospheric pressure, making it safer than conventional water reactors. The findings in this study show molten salt reactors would be the most efficient reactor to replace standard water reactors, which dominate the market in use of nuclear energy production. This study found a strong link between the thermal efficiency of the plant and the pressure and temperature at which it runs. Reactor core volumes also appeared to have a small effect on the efficiencies. Power flux density was calculated for each style of reactor and compared to other parameters but no distinct relationship was found between them.
Geothermal Power: Factors affecting the performance of Binary Plants
A meta-study is conducted investigating the effect of plant parameters on the power output and efficiency of geothermal binary cycle power plants. Production well depth, geofluid temperature and mass flow rate are the parameters considered. An increase in mass flow rate is shown to increase both power output and efficiency. It is shown that a distinction can be made between two basic types of binary plants based off of mass flow and performance data. The well depth is shown to have no effect on plant performance. In addition, condenser parameters were investigated and the highest efficiency condenser system is determined.
Affects of the Cold Water Pipe Depth in Ocean Thermal Energy Converter Plants with respect to Power Generation Efficiency
The Ocean provides an extensive renewable energy source. It is the exploitation of the thermal gradient between the warmed surface water and the deep cold water. A heat engine was developed to use the surface water as a heat source and the deep water as a cold source in order to convert thermal energy into mechanical energy and generate electricity. This process is called Ocean Thermal Energy Conversion (OTEC). This paper presents the three different types of OTEC power plants: closed-cycle, open-cycle and hybrid-cycle, showing real and conceptual examples of each. All three systems are analyzed in terms of gross power, net power, efficiency and size. Furthermore, the depth of the cold water pipe is discussed and related to the net power generation of the OTEC plant. The power generation efficiency of the plant increases as the gross power production increases. This is due to the depth of the cold water pipe and amount of power used by the cold water pipe pump.
Analysis of Industrial Syngas Production from Biomass
This meta-study provides a comparison across various gasification systems on the production of syngas from biomass as feedstock. The gasifier configuration systems analysed included; fixed-bed, fluidized, plasma, and entrained, and the effect of operational parameters on the syngas volume and composition were obtained and analysed across a number of studies. The relationships between efficiency, temperatures within the system, equivalence ratio, fuel quality, and biomass fuel types were investigated and it was shown that ER was the most influential operating parameter. A small generalised comparison between existing competing energy sources was also performed with respect to biofuels.
Tri-generation and combined cycles: thermodynamic analysis of prime movers in standalone and hybrid configurations
The global movement towards lower carbon economies and distributed energy requires the realisation of improved energy generation methods. Tri-generation is a method of optimising the thermal efficiency of energy generation through waste heat recapturing and can simultaneously provide heating, cooling and electrical output to meet building energy demands. A meta-analysis was conducted to analyse the performance of various prime movers utilised in tri-generation applications. Through this study it was determined that the efficiency of tri-generation and combined cycles can be optimised through a hybridisation of prime movers.
Fusion energy is one of the promising energy sources of the future, with a practically limitless abundance of hydrogen in the universe and earth, it has the potential to replace current energy technologies being theoretically superior in efficiency with minimal environmental impact. A systematic review and meta-analysis of its thermodynamic properties, including the examination of the efficiency of underlying technologies and fusion causing techniques was conducted to examine the potential of this technology as a viable energy source. Through these methods we obtained thermodynamic data relating to to the efficiency of fusion engines, such as the Tokamak, Direct Pulse, Z-Pinch and Fusor style fusion engines, and the underlying technologies relating to conduction and radiation losses in a fusion engine in order to assess current and projected thermodynamic efficiencies and hypothesise potential research requirements to make fusion technology viable. From this research it is concluded that the main flaw in fusion technology is the inability to properly address radiation and conduction losses which minimise the power output of any fusion reactor. Furthermore, while it is necessary to develop these technologies for the development of working fusion technology, their applications to other energy industries, such as solar and nuclear fission, would be more beneficial to the clean energy near future than to the long term goal of fusion technology.
Solar Power Concentrators for Space Applications
Space based solar power is an attractive solution to growing energy needs, overcoming the operational downtime and atmospheric losses inherent to terrestrial solar technologies. Ideal solar satellites include concentrator systems in order to produce a high specific power output, keeping mass low for economic launch. A meta analysis of photovoltaic concentrator research is presented to determine viability in space applications, considering contributions to cell heating, subcell current matching and efficiency of the InGaP/GaAs/Ge multi-junction cell. We find that the CaF2 Fresnel lens is an optimal choice with an efficiency increase of 4.9% at 17 suns. The large range of concentration ratio, low mass, compact design and minimal effect on spectral irradiance allow a wide space for optimisation in temperature control, whilst the current matching conditions under concentration can be regulated by appropriate tunnel junction width and bandgap.
Copyright (c) 2016 PAM Review: Energy Science & Technology
A meta-study of the effect of thermodynamic parameters on the efficiency of geothermal power plants worldwide
As global energy demand rises, the search for viable alternative fuel sources continues. The practicality of geothermal energy to meet this demand is highly dependent on optimizing thermal efficiency. While geothermal energy is currently used in places like Western Australia for direct-heat applications such as leisure centres, developing a geothermal power plant in such an area depends on predicting which thermodynamic parameters optimize thermal efficiency. This meta-study focuses on the effect of geothermal operation parameters such as inlet pressure, temperature, mass flow rate, well depth and number of production wells on the thermal efficiency of geothermal power plants. Drawing data from 61 geothermal power plants around the world ranging in design capacity (MWe) and size, a meta-study on the thermal efficiency of plants operating under different thermodynamic cycles, namely single-flash, double-flash, binary Organic Rankine Cycle (ORC) and Kalina, is offered. These various thermodynamic parameters are analysed to determine the presence of observable thermal efficiency patterns or trends that may lead to the optimization of operation parameters for new geothermal plants. Based on the available published data reviewed, there are few trends which indicate how geothermal operation parameters affect thermal efficiency. Well depth may be an indicator of efficiency for geothermal power plants using ORC and double-flash cycles, however further data is required to support this conclusion.
This is the third issue of PAM Review, the peer-reviewed, subject specific student research journal of the School of Mathematical and Physical Sciences at the University of Technology Sydney. The student journal was first introduced into the third semester subject Energy Science and Technology (68412) in 2014 to allow for a practical student centered, authentic learning experience that is exciting and challenging and helps to facilitate desired graduate attributes. Energy, Science and Technology is a one-semester subject (class) that covers the thermodynamics of macroscopic and microscopic processes in the context of energy production, energy saving and related applications. This third semester subject is open to students in science as well as engineering.
Photovoltaic Cell: Optimum Photon Utilisation
In the 21st century, global energy consumption has increased exponentially and hence, sustainable energy sources are essential to accommodate for this. Advancements within photovoltaics, in regards to light trapping, has demonstrated to be a promising field of dramatically improving the efficiency of solar cells. This improvement is done by using different nanostructures, which enables solar cells to use the light spectrum emitted more efficiently. The purpose of this meta study is to investigate irreversible entropic losses related to light trapping. In this respect, the observation is aimed at how nanostructures on a silicon substrate captures high energy incident photons. Furthermore, different types of nanostructures are then investigated and compared, using the étendue ratio during light trapping. It is predicted that étendue mismatching is a parasitic entropy generation variable, and that the matching has an effect on the open circuit voltage of the solar cell. Although solar cells do have their limiting efficiencies, according to the Shockley-Queisser theory and Yablonovitch limit, with careful engineering and manufacturing practices, these irreversible entropic losses could be minimized. Further research in energy losses, due to entropy generation, may guide nanostructures and photonics in exceeding past these limits. Keywords: Photovoltaic cell; Shockley-Queisser; Solar cell nanostructures; Solar cell intrinsic and extrinsic losses; entropy; étendue; light trapping; Shockley Queisser; Geometry; Meta-study
Meta-study: Analysis of thermoelectric figure of merit parameters for silicides with various doping agents
Thermoelectric (TE) materials are increasingly promising for power generation in medium to high-temperature environments. Recent research on thermoelectric generators (TEGs) has determined the thermodynamic properties which impact the total efficiency and figure of merit (ZT) of these materials. A large Seebeck coefficient, high electrical conductivity and low thermal conductivity optimise ZT. This meta-study investigates silicides for potential TEG applications due to their high chemical stability and higher natural abundance than other TE materials. Data on the thermoelectric properties of CrSi2, FeSi2, Mg2Si and MnSi2, with a range of dopants, was sourced from a wide scope of literature and is analysed. The above thermodynamic properties contributing to ZT for each of these materials are graphed between 300 and 1000 K. It was found that chromium silicides are most effective at a temperature range of 600-800 K, and undoped magnesium silicides are most effective around 900 K. Oxide addition to β-FeSi2 produced relatively high ZT scores (ZT ≈ 0.5) among iron silicides. Rhenium substitution in manganese silicides produced a maximum figure of merit (1.05) at 900 K. Supersaturation via liquid quenching was determined to maintain high rhenium substitution and this technique may be the key to further improving the thermoelectric properties of other silicides.
Macro to Nano: Scaling Effects of Bi2Te3 Thermoelectric Generators for Applications in Space
For decades research and development has been committed to improving the Figure of Merit (ZT) of Bismuth Telluride (Bi2Te3) Thermoelectric Generators (TEG) and has reached its limit at ≈1. This Meta-study aims to determine if further improvements can be made when the size of TEGs decrease. To quantify the change from macro to nano scale the change in ZT, thermal and electrical conductance, Seebeck coefficient and power factor as the size of the thermoelements decrease has been investigated as well as how Wiedemann-Franz (WF) law holds on the nanoscale. This meta-study was conducted by evaluating and comparing developments in TEGs for the past three decades. Based on theory it was expected that increases in ZT would occur as the thermoelement dimensions are reduced due to increased scattering of electrons and phonons as well as the increased density of electronic states. Increases to ZT due to these effects was not observed in experimental data due to difficulties in nanoscale production. This meta-study observed some indicators that the theory is correct in reduced thermal conduction from increased phonon and electron scattering and that phonon scattering was greater than electron scattering. Furthermore, a weak indication that WF law is not applicable on the nanoscale due to the scattering suggesting a decoupling of electrical and thermal conduction which is not achievable in macro scale TEGs
Meta-study Focusing on Abiotic Cells for Human Implants
Abstract: Powering implantable devices in human body with a glucose based fuel cell (GFC) offers an alternative to non-rechargeable batteries that typically require routine invasive surgery. There are three main approaches for GFCs to oxidise glucose. Enzymatic Fuel Cells are selective and have a high reaction rate but are unstable as the proteins can denature giving the cell a short lifespan. Microbial Fuel Cells use microbes to break down glucose to produce electrons. However they possess the danger of cell leakages that can introduce the microbes to the patient and risk possible infection. Abiotic Fuel Cells employ inorganic catalysts, typically a noble metal alloy or metallic carbon to oxidise and reduce glucose and oxygen respectively. Abiotic is the safest and most stable of the three but possesses the lowest output due to the electrodes inability to target glucose specifically. This meta-study investigates for Abiotic Glucose Fuel Cell being the most viable candidate of the three for possible use in autonomous medical devices. We will assess current abiotic fuel cells on the thermodynamic parameters of output voltage, current/current density, power density and efficiency. The kinetic parameters of internal resistance and rate at which membranes transport electrons will also be assessed. Operational parameters of lifespan and overall architecture will also be assessed to further understand the conditions and materials these cells were produced. Keywords: Glucose; Fuel Cell; Meta-study; Enzymatic; Microbial; Abiotic; Implantable Devices
Meta-Analysis on Optimised Parameters for Energy Harvesting Thermoelectric Generators in the Human Body
Small-scale energy harvesting thermoelectric generators could replace bulky batteries completely when in conjunction with a supercapacitor for biomedical devices. Organic material is cost efficient, flexible and easily processed but has poor thermoelectric properties. Recent studies have investigated the combination of inorganic and organic materials for thermoelectric materials in an attempt to improve the figure of merit, Seebeck coefficient and power factor. This meta-study examines the most effective ratio of PEDOT: PSS to Bi2Te3 thermoelectric material by analysing the Seebeck coefficient, electrical and thermal conductivity, the power factor and figure of merit for varying weight-for-weight percentage of PEDOT: PSS material. This paper also assesses the viability of hybrid thermoelectric materials with a focus on the synthesis process. The parameter of the thermal gradient found in the human body was used; approximated to 32-37°C from the human body to the ambient temperature of ~300 K. It was found that the peak in electrical conductivity was between 90%―96% PEDOT: PSS material. From this the optimal ratio of PEDOT: PSS to Bi2Te3 is between 90%―96% PEDOT: PSS material since the Seebeck coefficient decrease with increase organic percentage smoothly. Overall, this study suggests the use of an organic: inorganic hybrid TEG, coupled with a supercapacitor, is a commercially viable device for a variety of implantable biomedical devices.
Integrated Gasification Combined Cycle from coal
An integrated gasification combined cycle (IGCC) is a technology that uses a high pressure gasifier to turn coal, a carbon based fuels into pressurized gas, this is also known as synthesis gas or syngas. The IGCC system consist of 4 main structures; air compression and separation unit, gasifier, combustion and steam turbine and heat recovery generator. A meta-analysis was conducted to investigate possible relationships between the efficiency and types of gasifiers used in the integrated gasification combined cycle in terms of the key thermodynamic laws. Through this analysis correlations were established between varying coal compositions, types of gasification systems and thermal efficiency. It was found that the updraft gasifier had the highest efficiency across most reports, thus making this procedure the most efficient with today’s current knowledge in terms of the thermodynamic principles associated with coal-fired power plants. It was also established that coal with lower moisture content will generally allow a system to be more efficient.
Environmental Effect on Wind Farm Efficiency and Power Production
A meta-study is conducted investigating the effect of wind farm and turbine sites on the thermodynamic factors that affect energy production. Site deviations in surface roughness length, diurnal temperature changes of turbine and generation density and thermally stratified wind distributions are the parameters considered. The environment should be a significant factor in the placement of new wind farm sites. Further it is shown that with increasing wind velocity distributions negatively impacts efficiency of the turbine system and power output is decreased.
Efficiency of 2D Photonic Crystal Emitters in Thermophotovoltaic Systems
Thermophotovoltaic (TPV) systems have the potential to convert energy in a very efficient way by using 2D photonic crystal (PhC) emitters. Recent advancements in TPV technology have developed many methods for effectively generating power. These recent advancements propose that emitters can suppress low energy photon emissions while increasing higher energy photon emissions. This can be achieved by utilising new 2D photonic crystal (PhC) structures on the surface of the emitter with varying diameter and shape. In this meta study we consider the multiple design fabrications of photonic crystal emitters and compare the efficiencies, power densities, and their potential use for converting different wavelengths into heat and power. This is done by analysing the thermodynamic factors present in the system that could potentially reduce the efficiency, and therefore power generation, of the thermophotovoltaic cell. This study found that certain shapes and materials can impact on the PhC structure and its ability to emit energy.
Comparison of Fuel Yield of Biomaterials Between Fast Pyrolysis and Gasification
Pyrolysis is a viable method of extracting combustible fuels as gases or liquids from various, high carbon and hydrogen containing biomaterials. This Meta-study attempts to find the ideal combinations of processes for maximising biofuel output by comparing a range of biomaterials (cotton stalks, algae and peach scraps), put through the two primary methods of pyrolysis, through analysis of reactor type, Temperature, particle size and lower heating value achieved from biofuel output. It is proposed that the fast pyrolysis of Algae in a Fluidized bed reactor at a temperature of 550°C is the optimum combination of parameters for maximising biofuel output in terms of bio-oil yield and lower heating value (LHV) in kJ/kg.
Copyright (c) 2017 PAM Review: Energy Science & Technology
Table of contents and group photo - PAM Review Vol. 4 (2017).