Queensland

Geothermal

Energy

Centre of

Excellence

ANNUAL REPORT 2009 - 2010

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Mission

To work with equipment manufacturers, geothermal companies, geothermal power station designers and consultants to research, develop and demonstrate new technologies for the geothermal industry and to collaborate with the Queensland State Government and other stakeholders to develop and promote geothermal energy in Queensland and in Australia.

Contact: Professor H Gurgenci, Director Queensland Geothermal Energy Centre of Excellence School of Mechanical and Mining Engineering The University of Queensland St Lucia, Queensland 4072 Australia Tel: +61 7 3365 3607 h.gurgenci@uq.edu.au www.uq.edu.au/geothermal

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Table of Contents Mission……………………………………………………………………………………………………………………………………………………………..1

Foreword by Chair, Advisory Board……………………………………………………………………………………………………………………3

Executive Summary……………………………………………………………………………………………………………………………………………4

Advisory Board……………………………………………………………………………………………………………………………………………..…..5

Reservoir Program .................................................................................................................................................. 6

High Heat Producing Granites ................................................................................................................... 6

Alteration Mineralogy ................................................................................................................................ 7

Power Conversion Program ................................................................................................................................. 11

Analytical Studies .................................................................................................................................... 12

Experimental Studies ............................................................................................................................... 13

Heat Exchangers Program ................................................................................................................................... 15

Advanced Heat Exchangers ..................................................................................................................... 15

Design and Optimisation of Natural Draft Dry Cooling Towers ............................................................. 17

Transmission program .......................................................................................................................................... 18

Stability and Reliability of the Power Systems ........................................................................................ 18

Queensland Geothermal Power Deployment Costs ................................................................................. 20

QGECE Stakeholders Workshop, March 2010 ..................................................................................................... 21

Mobile Plant Focus Group Meeting ..................................................................................................................... 21

Technical Advisory Committee Meetings .............................................................................................................. 21

Australian Geothermal Energy Group (AGEG) ................................................................................................... 22

Australian Geothermal Energy Association (AGEA) ............................................................................................ 22

Undergraduate programs ..................................................................................................................................... 23

Postgraduate Students .......................................................................................................................................... 23

List of Competitive Grants .................................................................................................................................... 24

Projects with industry participation ..................................................................................................................... 24

Number of research projects undertaken in Queensland ...................................................................................... 24

Financial Summary ............................................................................................................................................... 25

Refereed Journal Publications .............................................................................................................................. 26

Refereed Conference Proceedings ........................................................................................................................ 28

Other Conference Presentations ........................................................................................................................... 29

Reports .................................................................................................................................................................. 30

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Foreword by Chair, Advisory Board

Established in September 2007 by a $15 million grant from the Queensland State Government from its Renewable Energy Development Fund and a $3.3 million contribution of expertise and other resources from The University of Queensland, the Queensland Geothermal Energy Centre of Excellence (QGECE) is already having an impact on the development of an Australian geothermal energy sector early in its life.

The QGECE is actively pursuing its mission to hasten the development of the industry through a research and development program which is focussing on scientific and technological innovations which will increase geothermal power plant efficiencies (turbines, heat exchanges and cooling towers), particularly in hot, arid regions; address long distance power transmission issues; and, increase understanding of geothermal reservoir geochemistry to enhance resource identification. To support the program, strong national and international scientific, research and technology commercialisation collaborations have already been established.

The Queensland State Government remains strongly committed to the development of this energy source as is evidenced through its commitment of $5 million to the Coastal Geothermal Energy initiative under the direction of the Geological Survey of Queensland and through the commitment of up to $4.3 million to Ergon to upgrade the only operating geothermal power station in Australia at Birdsville. The QGECE is actively associated with both of these projects. The recent passage of the Geothermal Energy Bill 2010, with accompanying Regulations to be forthcoming next year should provide added incentive and certainty for exploration and investment in the development of the geothermal resources of Queensland. The QGECE is involved in discussions aimed at identifying the role that it can play in encouraging such investment through increased knowledge of the resource and improved efficiencies in geothermal energy power conversion.

I would like to express my appreciation to my fellow members of the Board for their support and guidance to the QGECE Director, Professor Hal Gurgenci, and the staff of the Centre through the year. Special thanks is owed to the invited members from industry and government who serve on the QGECE’s Technical Advisory Committees established to provide specialist advice and critique of the research and development programs of the Centre.

Professor Trevor Grigg

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Executive Summary

It has been a great first year for the Queensland Geothermal Energy Centre of Excellence, during which we have achieved the following:

• We formed a strong Advisory Board with very senior appointments bringing in substantive expertise to provide advice to the Centre in geothermal energy technology and industry issues, research commercialisation and research management.

• Our research strategies were strongly endorsed by its industry, academic and government stakeholders in the first Stakeholders Workshop held in March 2010. The Workshop had an impressive turn-out of 70 people representing eleven geothermal energy companies, two industry associations, seven service/consulting companies, three universities and research institutions, and two state governments. Their feedback was discussed at the QGECE Board Strategy Workshop in June 2010 and helped the Centre establish our future directions and current research portfolio.

• Technical Advisory Committees of industry experts were established for each one of our research areas. The aim of a Technical Advisory Committee is to provide ongoing detailed technical scrutiny of objectives and progress in its focus area. These committees held their inaugural meetings in June – July 2010 and strongly endorsed Centre research strategies. The Technical Advisory Committee membership is shown on page 22.

Another exciting development is the research collaboration agreement the Centre is signing with the US Turbine and Plant Manufacturer Verdicorp. This provides a platform to transfer the outputs of the Centre research to the geothermal industry in the area of supercritical turbines and cycles. An early manifestation of this collaboration will be the portable test plant expected to be commissioned in 2011. This will be a portable facility capable of generating 75 kWe from geothermal or waste heat sources. It will provide QGECE with a large-scale outdoors test facility that will enable the development and testing of sub- and transcritical power cycles, turbines and control systems.

Another highlight of last year was the signing of a Memorandum of Understanding (MoU) with the German Research Centre for Geosciences (GFZ) to work together to increase our understanding of heat produced in the Earth and the dependency of heat flow anomalies on radiogenic heat generation in rocks of the upper Earth

crust. The QGECE and the GFZ will be working towards a joint Workshop to be held in Australia next year.

There are many other significant achievements highlighted in the reports from individual programs on the following pages including the establishment of out high-pressure laboratory to test small supercritical turbines; the heat exchanger laboratory where we started testing metal foams for heat transfer enhancement and scaled cooling towers; and collaboration with Power Link towards simulating the likely scenarios for connecting remote geothermal power to the Queensland power grid.

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Advisory Board

The Queensland Geothermal Energy Centre of Excellence has an Advisory Board whose role is to set and monitor the strategic direction of the Centre and to monitor its performance. The following were the members of the Advisory Board as of 30 June 2010.

Professor Trevor Grigg - Independent Chair

Mr Greg Nielsen Office of Clean Energy, Department of Employment, Economic Development & Innovation

Professor Max Lu Office of the Vice-Chancellor, The University of Queensland

Professor Graham Schaffer Faculty of Engineering, Architecture, Information Technology & Electrical Engineering, The University of Queensland

Dr Richard Suttill Origin Energy

Dr Adrian Williams Buddina Projects

Mr Greg Withers Office of Climate Change, Department of Environment & Resource Management

Professor Halim Gurgenci - Centre Director

School of Mechanical & Mining Engineering, The University of Queensland

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Research

Reservoir Program Understanding Queensland Geothermal Resources and Developing New for

Radiogenic Granite Exploration

Program leader Dr Tonguc Uysal

Research team Ms Victoria Marshall, QGECE PhD Student Mr Craig McClarren, QGECE PhD Student Mr Alexander Middleton, QGECE PhD Student Mr Jacobus van Zyl, QGECE PhD Student Mr Behnam Talebi, Part-time QGECE PhD Student Dr Massimo Gasparon, Associate Professor

Collecting and analysing rock and water samples from Queensland, Western Australia and South Australia to develop new exploration tools and discover new hot rock resources

Many similarities identified between European and Australian EGS

Collaborate with GFZ-Potsdam to explore these similarities

This Program is aiming to answer the following questions:

• What makes granite “hot”? • What are the origins of the granites in Queensland? • Why do some granites have more heat-producing elements than others? • What caused the generation of heat-producing granites in Queensland? • How can we locate such granites without drilling deep exploration holes?

We are currently producing a comprehensive geochemical dataset including major/trace element and isotope geochemistry, and radiometric age dating of granites and hydrothermal alteration minerals in selected areas in Queensland, WA and north-central SA (Figures 1-3); studying trace element and noble gas geochemistry of near-surface water samples from geothermal potential areas in Queensland; evaluating geochemical, mineralogical and geochronological data in relation to regional geology; and investigating the Cooper Basin hosting some of the hottest granites in the world, a superb natural laboratory for understanding of radiogenic heat enrichment process.

In a separate project, we collaborate with others to examine sub-surface CO2 and their mineral precipitates from existing geothermal sites in Turkey with naturally elevated CO2 concentrations to develop an understanding of CO2 accumulation and degassing in tectonically active regimes and natural geothermal systems driven by CO2-rich fluids. This will help us model artificial CO2 injection in Australian hot sedimentary aquifers to enhance geothermal reservoir performance.

High Heat Producing Granites

To better understand the origin, tectonic setting and generation of high heat producing granites (HHPG) on the Australian continent and provide target criteria for the exploration of granite-hosted Enhanced Geothermal Systems (EGS), the QGECE is investigating European analogues. There are three areas of long-standing interest for EGS in Europe - Cornwall, UK; Soultz-sous-Forêts, France; and Erzgebirge, Germany. As shown in Table 1, they have higher than average heat flow (at surface and depth), and higher than average upper crustal levels of radioactive elements Uranium (U), Thorium (Th) and Potassium (K).

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We have identified many similarities between European and Australian HHPG, while noting differences (see the summary in Table 1). An agreement has been signed with the Deutsches GeoForschungsZentrum (GFZ) to collaborate in this area.

Table 1: Compositions of targeted HHPG for EGS1

EGS TARGETED GRANITES

AGE LITHOLOGY SiO2 K2O U Th

(Ma) (wt%) (wt%) (ppm) (ppm)

Carnmenellis Cornwall, UK

295-270 Mega-crystic biotite and two-mica granites

70-76 4-4.3 4.3-35 (12.1 mean)

11-25 (19.3 mean)

Land’s End Cornwall, UK

277-274.5

Early mega-crystic biotite granites, younger Li-siderophyllite granites

66-73 3.5-6 6.9-38 4.4-46.2

Soultz, France 334-319 Porphyritic monzogranite 67-69 3.8-4 6.2-14.1 23-37

Erzgebirge, Germany

325-315 Transitional I-S and A Type biotite granites, two-mica granites and S and A

Type Li-mica granites

67-77 (biotite)

3.8-5.4

9-30.9 10.4-34.3

71-76 (two-mica)

73-76 (Li-mica)

Cooper Basin, Australia

298-323 Coarse grained two feldspar biotite granite moderately weathered

11 - 27 17 - 117

Upper Continental Crust 66 3.4 2.7 10.7

A minerals exploration technique is adapted for locating future hot rock geothermal reservoirs

Alteration Mineralogy

The alteration mineralogy is one of the widely used techniques when performing exploration for potential ore deposits. However, this method has not yet been deployed for the acquisition of enhanced geothermal systems. In this project, alteration mineralogy of HHPG, particularly with the emphasis on trace element and stable isotope geochemistry is investigated. A successful outcome may revolutionise geothermal exploration techniques.

The principle areas of interest for sampling are the Cooper Basin, Galilee Basin, Innot Hot Springs region, Hodgkinson Province, Styx Basin, Maryborough Basin and North d’Aguillar Block, Wandilla Province. These research targets have been based on granitoidal emplacement during the Hunter-Bowen Supercycle and are Late Devonian to Triassic in age.

1 Charoy, B, 1985, Journal of Petrology, 27, Part 3, 571-604; Jefferies, N L, 1984, Proceedings of the Ussher Society,

6,35-40; Martel, D J, et al. 1990. Chemical Geology, 88, 207-221; Förster, H J, et al.., 1999, Journal of Petrology, 40, 11, 1613-1645; Taylor, S R and McLennan, S M, 1985, The Continental Crust: its Composition and Evolution, Blackwell Scientific Publications, 46

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The fluid history for Cooper Basin is being constructed to better understand the nature of the geothermal resource there

Core analysis results

Cores taken from the granite and overlying sediments in the Cooper Basin show varying degrees of alteration, with a range of incompatible element enrichment, such as U and Th. The highly altered zones have a predominant greisen-style sericite (illite) and re-precipitated quartz assemblage. We believe that this alteration may well have caused the localised enrichment in radiogenic element-bearing minerals such as illite, K-feldspar, and particularly accessory minerals (thorite etc.).

The fluid history of the Cooper Basin can be deduced from crystallinity and stable isotope analyses of the illite. Illite crystallinity is a useful indicator of the temperature gradient in active geothermal systems and for locating fossil hydrothermal systems associated with ore deposition. Illite crystallinity is controlled by crystallisation temperature, water/rock ratio, and time available for crystallization. Better-developed crystalline illites show narrower 001 basal illite peaks and have lower IC values. Such illites were formed at higher temperatures or during prolonged heating events. Higher IC values (wider peaks), on the other hand, indicate lower crystallisation temperatures and/or rapid precipitation during hydrothermal processes. Illite crystallinities are seen to progressively increase with increasing core depth, insinuating a higher crystallisation temperature and hence hydrothermal fluid temperature at depth. The granite intersected in Jolokia and McLeod 1 seems to have experienced highest temperatures.

Figure 4: Radon in Queensland borehole waters

Figures 1, 2 and 3: UQ is one of the few universities in Australia that provides access to most of the necessary equipment and laboratory facilities. Thus much of the analytical work such as ICP-MS for trace element analysis, ICP-OS for major element analysis and TIMS for radiogenic isotope and geochronological studies is being carried out within the UQ campus.

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Evidence of a major asteroid impact that occurred more than 300 million years ago in South Australia

Water geochemistry

Water samples have been collected over a large area of eastern Queensland, extending from Stanthorpe in the south to southern Cape York in the north. Sample geochemistry has been analysed by ICP-MS and by ICP-OES, the results of which are still presently being processed. Radon concentrations were measured in the field and that data is presented in Figure 4. At present, we have collected filtered and unfiltered water samples, and radon samples, from approximately forty sites and will continue to collect more from central and western Queensland in the coming months. We will soon be acquiring an on-site helium detector and we are currently formulating plans to collect helium samples for future in-lab isotope analysis. Both radon and helium are products of heat-producing U/Th decay series. Higher concentrations of these noble gases in the ground water indicate degassing from a U- and Th-rich source. In Figure 4, red and purple colours show areas with relatively high radon contents. These are particularly Hodgkinson Province near Cairns, Yarrol Province near Rockhampton and Stanthorpe granites.

Cooper Basin Impact

We found evidence of a major asteroid impact about 300 million years by examining the quartz crystals from rocks underlying the Cooper Basin (see Figure 5). The presence of signatures of shock metamorphism within the altered top basement zone suggests extensive hydrothermal activity triggered by a large asteroid impact, as has been documented in large impact structures2. Based on association of hydrothermal alteration with impact effects, the extent of the impact

aureole may be outlined by the altered zone, which covers an area larger than 10,000 km2 in the Cooper Basin. The evidence for impact3

Figure 5: Planar deformation features (PDF) in quartz deflected along a

has potential implications for the origin of K-U-Th enrichment in the basement.

post-impact fracture, McLoed-1 3745m

2 Uysal, I T, et al. 2001. Earth and Planetary Science Letters, 192, 281-289; Uysal, I T, et al. 2005. Contributions to

Mineralogy and Petrology, 149, 576-590; Pirajno, F., 2005. Australian J Earth Science, 52, 4/5, 587-606. 3 Glikson, A Y and Uysal, I T, 2010. Australian Geothermal Conference 2010.

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Work with Geological Surveys Queensland to explore what may be a major geothermal source in the basement of Galilee basin

Drummond Basin trace element geochemistry

Igneous rocks of the Drummond Basin occur as the basement of the adjacent Galilee Basin of Upper Carboniferous to Middle Triassic age. The late Permian coal deposits and carbonaceous pelitic rocks in the Galilee Basin are ideal heat insulating sediments that would store the radioactive heat generation in the basement. The Drummond Basin hydrothermal silica deposits are unique in having anomalously enriched incompatible element (Cs, Li, Be, W, U, Th and REE) concentrations in comparison to hydrothermal quartz veins from various granitic-pegmatitic systems elsewhere. In support of these arguments, temperatures of about 80°C at 1000 m were observed in coal seam gas drilling boreholes in the Galilee Basin (pers. commun. with A. Falkner - AGL) that indicate high heat flux from the basement. Furthermore, the vitrinite reflectance data obtained from core samples taken in past mineral exploration can be correlated with the geological maximum temperatures. In Galilee basin, these correlations consistently result in high temperature gradients (75 - 100ºC/km). Work continues in this area in a joint project between the QGECE and GSQ.

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Power Conversion Program Generating More Power from a Geothermal Reservoir

Program leader Dr Peter Jacobs

Research team Dr Andrew Rowland, Research Scientist Dr Emilie Sauret, Research Scientist Dr Paul Petrie-Repar, Research Scientist Mr Hugh Russell, Research Engineer Mr Aleks Atrens, QGECE PhD student Mr Jason Czapla, QGECE PhD student Mr Carlos Ventura, QGECE PhD student Mr Rajinesh Singh, QGECE PhD student Mr Braden Twomey, QGECE PhD student

Supercritical cycles and expanders will increase the power output from a given reservoir investment by up to 50%

The overall aim of is to increase the power output from a given capital investment in a geothermal reservoir by 50%. Increased power production while maintaining similar capital investment levels leads to a proportional and direct increase in the reward from a given subsurface investment. This is equivalent to achieving a higher electricity sales price and, obviously, would have a significant effect on whether a geothermal project proposal is seen as viable.

In a conventional Rankine cycle, a significant fraction of the geothermal heat is unutilized because of the heat exchanger irreversibilities caused by the constant evaporator temperature. This can be overcome by either a cycle where evaporation occurs over varying temperature range (i.e. Kalina) or a cycle where no evaporation occurs (i.e. the supercritical cycle in Figure 6). The QGECE focus is on the latter.

To minimise parasitic losses, the turbine with the supercritical inlet is designed to exit to a subcritical pressure and the cycle fluid condenses as in a regular Rankine cycle. Transcritical cycles (condensing cycles with supercritical heaters and expanders) with suitable, dense working fluids are expected to deliver higher power production compared to conventional Rankine cycles. The principal gain comes from allowing the high-side heat exchanger to more efficiently extract heat from the hot brine stream. The expanders that we study initially are radial-inflow turbines and the cycle fluids are refrigerants such as R134a and R245fa in the short term which will serve medium-temperature (150oC) geothermal applications, working up to high-pressure carbon dioxide in the long term for high-temperature EGS power conversion (250oC).

A recent paper4

describes the benefits of a supercritical cycle in comparison against conventional geothermal binary plants. This is a relatively new area. QGECE and a US manufacturing company Verdicorp has established a partnership to develop supercritical turbines and supercritical cycle equipment for geothermal, solar thermal and waste heat power generation applications and new cycle fluids and fluid mixtures suitable for supercritical cycles. We are expecting a small (<5 kW) laboratory prototype in 2011 and a relatively larger (100 kWe) unit in 2013 and aiming a field demonstration at 1-MWe scale after that.

4 Gurgenci, H, World Geothermal Congress 2010, Bali Indonesia.

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Figure 6: Temperature-Entropy (T-s) Diagram for R134a Supercritical Power Cycle

Figure 7: QGECE High-Pressure Power Test Loop

Facilities are being built to test QGECE supercritical expanders up to 100-kW size

.

Our activities fall into two broad categories: (1) analytical and computational modelling to enable the evaluation of technical concepts; and (2) experimental studies to prove the concepts via demonstration. The experimental work also anchors the analytic and computational work, allowing us to calibrate those modelling tools with reality. A high-pressure power plant test loop is being built to test supercritical expanders being designed and built by the QGECE.

Analytical Studies

Cycle and Working Fluid Analysis To set the context for the high-pressure loop design, a study of available fluids

was made. This study considered a range of temperatures for the various geothermal resources and a selection of sub-critical and transcritical cycle options.

For the temperatures limited to 150oC, R134a and R245fa transcritical cycles look promising. Figure 6 shows the transcritical R134a on a T-S diagram. Figure 7 shows the flow sheet for the implementation of this cycle in our laboratory. At higher temperatures, e.g. 250oC, a transcritical CO2 cycles offers the optimal solution provided there is access to a cooling medium at below 30oC to condense the CO2.

Turbine Design and Analysis Licences for the software packages RITAL and AXCENT (from Concepts

NREC) have been purchased to aid in the design of radial-inflow turbines. These are sophisticated packages and require expert users so a significant effort has been expended on getting some of the group familiar with it. We are now able to do preliminary design and CFD analysis of proposed machines and are presently learning to export the design data for further analysis and for manufacture of a trial rotor. Figure 8 shows one of the geometries considered in this project.

EVAPORATOR

COOLERCONDENSER

EXPANSIONVALVE

R134aT = 35°C

P=5000 kPam = 0.12 kg/s

R134aT = 140°C

R134aT = 75°C

P=1017 kPa

R134aT = 98°C

P = 1017 kPaP = 5000 kPa

Ethylene GlycolT = 150°C

m = 0.5 kg/s

Ethylene Glycol Out

Cooling Water T = 25°C

m = 0.5 kg/s

Cooling Water T = 25°C

m = 0.5 kg/s

Cooling Water Out

Cooling Water Out

Pmax = 20000 kPa

Pmax = 10000 kPa Pmax = 10000 kPa

R134aT = 35°C

P=1017 kPa

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To complement the use of commercial codes we are continuing the development of our in-house code Eilmer3 as a flow solver suitable for turbomachinery flows. A flow solver capable of handling fully three-dimensional geometries and complex equations of state will be an important tool in analysing flow losses in dense-gas turbines. The work of including body-force terms for a rotating frame of reference and the implementation of a “mixing plane” boundary between stator and rotor inlet has been done and the results presented at the ECCOMAS CFD conference mid-year. Recent efforts have focused on the importing and exporting of meshes so that we could make use of the RITAL/AXCENT initial designs.

Figure 8: Model of Stator Blades and Turbine Rotor Figure 9: Rotor and Stator Blades with Mesh for

Computational Analysis

A range of commercial and in-house turbine design and CFD software give us the ability to produce high-fidelity simulations of industrial turbines under design and off-design conditions

It has been difficult to find standard test cases for radial turbines in order to calibrate our turbine flow analysis. Initially we have made use of a NASA design from the 1960s, however, the documentation for the NASA turbine is missing some important details. Present efforts have refocussed on another small, high-pressure turbine designed through a US Army program for small power applications. The three-dimensional geometry has been recreated using RITAL and AXCENT and the flow analysis capability of the PushButtonCFD component of the AXCENT software package is being explored presently. A comparison between this software, Ansys-CFX, Fluent and Eilmer3 is also being made using the experimental results as the baseline.

Experimental Studies

In the QGECE laboratory on the UQ St Lucia campus, two small-scale cycle rigs are being built. The first is a low-pressure loop with air as the working fluid and a turbocharger as the expander. On its own, it will become the test bed for a PhD thesis on control. This thesis will investigate techniques such as predictive control of components such as the compressor, turbine and bypass valves and of the integrated loop. Optimal control of the power loop in the presence of changing conditions is important for both the safety of lab-scale experiments and for achieving adequate performance of the field demonstration units.

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Figure 10: QGECE Research Engineer Hugh Russell with the Small Scale Laboratory ORC System

Figure 11: Adrian Marquardt, at the ITEE Innovation Expo, showing an Output Node PCB he designed and built for the QGECE Distributed Control System as part of his final year mechatronic Thesis

In-house facilities to design and build and test small supercritical turbines offer a development environment unique in Australia

The second loop being developed in the QGECE St Lucia laboratory is a dense-fluid loop with R134a as the working fluid (Figure 10). It will become the initial test bed for dense-fluid expanders and be our entry into transcritical cycles. Presently a scroll expander is in place but in early 2011, we expect to have a small impulse turbine of our own design and construction.

As part of the development of our laboratory facilities, we have been building some custom instrumentation and control devices. These include analog sensors for temperature, pressure and speed with microcontroller-based node boards. The node boards are networked to supervisory computer via RS485 with MODBUS protocol. Although this network has low bandwidth, it integrates nicely with the variable-speed motor control for our compressors and the control valves embedded in the loops.

Successful outcome of the above projects will produce new expanders for transcritical cycles capable of extracting significantly more power from the same geothermal brine stream. We will be collaborating with the US turbine manufacturer Verdicorp to transform the research outcomes to commercial equipment. As part of this collaboration, we are planning to have an experimental rig in mid 2011 with a capacity of 75-100 kWe. The first implementation will use conventional organic Rankine cycle but the rig will have the high-pressure capability to test supercritical turbines to be developed by the QGECE in the future.

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Heat Exchangers Program Advanced Heat Exchanger Technologies and Natural Draft Dry Cooling Towers

Program leader Dr Kamel Hooman

Research team Dr Zhiqiang Guan, Research Scientist Dr Katsuyoshi Tanimizu, Research Scientist (until June 2010) Mr Ampon Chumpia, QGECE PhD student Mr Mehryar Sakhaei, QGECE PhD student Mr Zheng Zou, QGECE PhD student Mr Mostafa Odabaee, QGECE PhD student Mr Yuanshen Lu, QGECE PhD student

Adoption of natural draft dry cooling towers will increase the net power production by up to 15% in Australian geothermal plants with air-cooled condensers.

The QGECE research is aimed at advanced heat exchanger technologies and new construction methods to increase the commercial feasibility of natural draft dry cooling towers in Australia.

Based on a cycle efficiency of 15%, a 50-MWe power plant needs to have a 283-MWe heat sink. To dispose of this heat using a wet cooling tower consumes water at about a rate of 100 kg/s or 3.2 million tonnes per year. In many geothermal plant locations, the water is too scarce to be used so profligately and air cooling is the only option. Air-cooled heat exchangers work by forcing air across a heat exchanger array either using electrical fans or the buoyancy-driven updraft through a tall tower acting like a chimney. Both of these types are referred to as dry cooling towers even though fan-driven systems usually look like large squat boxes rather than towers.

The fan-driven systems can be built quickly and at relatively low cost but their operating costs are higher due to their higher maintenance requirements and the parasitic losses associated with running the fans. At high ambient temperatures, the air velocity needs to be increased to try to maintain the cooling load. This increases the parasitic power losses and the net plant output falls.

Natural draft dry cooling towers have low maintenance requirements and no parasitic losses but they are also much more expensive to build and they also suffer similar performance losses on hot days.

The QGECE research will focus mainly on natural draft dry cooling towers and seek improvements through the following avenues: (a) Advanced heat exchanger technologies; and (b) tower design optimisation and innovation.

Advanced Heat Exchangers

Compared to coal-fired power plants, geothermal plants have higher heat dump requirements due to their lower efficiencies. Therefore, the impact of efficient heat exchangers is higher on the plant economics.

Air-cooled condensers traditionally use finned tube bundles where the cycle fluid condenses in the tubes. There are two competing performance requirements: (a) higher heat transfer per tube; and (b) lower air pressure drop. Fins improve the heat transfer performance but at the same time lead to higher pressure drop compared to bare tubes. A good design is a successful trade-off between these two opposing effects.

Given the fact that fins can increase the pressure drop significantly, the question is to see if a more efficient heat transfer augmentation technique can be found with less pressure drop. An alternative to finned tubes is a class of porous materials called metal foams. They offer low densities and novel thermal, mechanical, electrical and acoustic properties mainly because the foams are lightweight with

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QGECE developing a new heat exchanger technology using porous metal foams.

These offer substantial improvements over conventional alternatives.

Numerical and experimental studies are being conducted.

high strength and rigidity and high surface area. These help the energy absorption and heat transfer in heat exchangers where the rate of heat transfer is extremely enhanced by conducting the heat to the material struts, which have a large accessible surface area per unit volume, along with high interaction with the fluid flowing through them. As the flow paths through the foams are interconnected the flow will be available in all areas leading to smaller and lighter heat exchangers.

Parametric models have been generated for prediction of heat transfer and pressure drop resistance of finned tube heat exchangers by reducing their complex geometry into a standard porous medium paradigm5

Numerical models have been generated

. The approach was verified against published experimental data and established correlations and serves as a basis for CFD simulations and design of the cooling tower and fan-cooled condensers.

6

to simulate the flow and heat transfer characteristics for a foam-covered tube. These models are now being expanded to cover tube bundles. To validate the models, an experimental apparatus was constructed to measure heat transfer and pressure drop for foam covered tubes and tube bundles. A single foam-wrapped tube was examined first under the isothermal (similar to a condenser) conditions. Similar experiments are now being conducted on a finned-tube bundle. A very accurate pressure transducer has been purchased for this purpose. Things are ready for the next phase, which is examining the foam-wrapped tube bundles.

Figure 12: QGECE students, Chumpia and Odabaee, testing heat transfer from a foam-covered single tube placed in a cooling air stream

Figure 13: Gurgenci and Hooman with QGECE students Odabaee and Sakhaei examining the scaled laboratory model for a natural draft dry cooling tower

5 Hooman and Gurgenci, Transport in Porous Media, 84(2), 257-273 (2010) 6 Odabaee, Hooman and Gurgenci, to be published in Transport in Porous Media.

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A scaled tower was built to study air flows in natural draft cooling towers at different environmental conditions

Design and Optimisation of Natural Draft Dry Cooling Towers

A small scale (2m height) cooling tower (made of polycarbonate) is built in our QGECE labs and is shown in Figure 13. An electrical heater and an in-house developed temperature control box are utilized to allow for preliminary temperature measurements. The results will be applicable to real-size towers through the cooling tower scaling law by the QGECE7

A MATLAB program has been developed for sizing the heat exchangers and the cooling tower geometry. This has been incorporated into the QGECE power plant cycle analysis program to predict the performance of geothermal plants under varying ambient conditions.

. The scaling law was developed and validated versus numerical and experimental data for both towers with a horizontal placement of the heat exchangers as well as Heller towers where the heat exchangers are oriented vertically.

Figure 14: Solar enhanced natural draft dry cooling tower

Figure 15: The type of equipment being considered for dust monitoring

A dust monitoring program starting next year will characterise the ambient dust in Cooper Basin in terms of its effect on heat exchanger design

An interesting enhancement of the natural draft cooling tower technology is being considered in a PhD study that started this year. As shown in Figure 14, the proposal is to use solar heat to increase the buoyancy in the cooling tower after the air is past the heat exchangers. Preliminary studies show that the size of tower and heat exchanger can be greatly reduced by using this enhancement. Work is in progress towards parametric optimisation and cost analysis.

Concerns were raised in the March 2010 Stakeholders Workshop about the effect of dust, especially when using advanced heat exchanger technologies such as metal foams. A new project was initiated this year for long-term monitoring of environmental dust in Cooper Basin. Most dust monitoring studies in the past were limited to respirable dust with limited relevance to heat exchanger design. Total suspended particulate material will be continuously monitored in this project using self-powered stand-alone equipment (e.g. see Figure 15); the dust concentration and the size distribution will be continuously sampled over an extended period of time to record daily, seasonal and yearly variations in dust.

7 Tanimizu, K, Hooman, K. (2010) Scaling laws for a natural draft cooling tower: Porous medium modeling of the heat exchangers. In: 3nd International Conference on Porous Media and its Applications in Science and Engineering 2010

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Transmission program Connecting remotely generated geothermal electricity to the national power grid

Program leader Professor Tapan Saha

Research team Dr Mehdi Eghbal, Research Scientist Ms Huong Mai Nguyen, QGECE PhD student Mr Kazi Nazmul Hasan, QGECE PhD student

How to connect remotely generated geothermal power to the national electricity grid at minimum cost while maintaining system reliability and stability

The objective of this project is to investigate High Voltage DC (HVDC) and high Voltage AC (HVAC) transmission link options to interconnect expected geothermal power plants to a remotely located existing HVAC power grid. Specifically, power system stability and reliability, cost benefit, reactive power requirements and transmission loss issues of each option are investigated.

Stability and Reliability of the Power Systems

The two PhD projects address the two issues related to bringing remote generation to the grid: stability of the supply and reliability of the supply:

• System Stability – Different aspects of system stability including voltage stability and small signal stability are investigated. A comparative study on the performance of HVAC and HVDC transmission lines is in progress. The outcome of this project will be stability analysis tools useful for integrating remotely located geothermal energy sources into the Australian National Electricity Market (NEM) Grid.

• System reliability project – Reliability and cost benefit assessment of different transmission options is investigated. The outcome of the project will be a probabilistic reliability analysis tool useful for integrating geothermal energies into the NEM with volatile market situations, including uncertainties associated with the carbon price.

Figure16:Point of collapse related to interconnection distance

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HVAC and HVDC power flow models are developed using real Queensland power network data

The two main technologies for HVDC/HVAC conversion were reviewed and compared for their application in bringing remote geothermal generation, e.g. Cooper Basin, to the national grid on HVDC lines. Current Source Converters have been found to be superior to the Voltage Source Converter (VSC) option.

HVAC and HVDC power flow models were developed in the DIgSILENT Power Factory software environment. A simplified 14 generator South-East Australian power system was used to implement voltage and small signal stability analyses. A measure of stability is provided by the so-called Point of Collapse (PoC), which represents the overloading that can be tolerated before the power network collapses. Results of this work as shown in Figure 16 indicate that bipolar HVDC is clearly more stable than HVAC and hybrid HVDC even at short distances. Moreover, when the transmission distance is increased, the stability offered by bipolar HVDC stays constant whereas the stability of HVAC and Hybrid HVDC drops almost linearly with the transmission distance8

A parallel study is being undertaken to examine how the power system reliability is affected by different transmission options. Market simulation tool (PLEXOS) is under investigation to address the electricity market behaviour. A comparative reliability versus cost benefit analysis between HVDC and HVAC link options for connecting future geothermal power plants to the Australian electricity network will be conducted.

. The methodology developed in this study needs to be extended to the Australian network grid.

Figure 17: Queensland transmission network areas www.powerlink.com.au/asp/index.asp?sid=5056&page=Corporate/Documents&cid=5250&gid=597

Figure 18: Professor T Saha and the QGECE PhD student K N Hasan

8 M H Nguyen, T K Saha and M Eghbal, 2010 IEEE PES General Meeting, July 26 - 29, 2010, Minneapolis,

Minnesota, USA

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The study will estimate levelised grid-connected electricity cost from future geothermal power plants in different Queensland locations and exploiting different geothermal resource types.

Queensland Geothermal Power Deployment Costs

An investigation is under way to estimate the cost of connecting possible geothermal energy resources to the Queensland electricity grid. Levelised cost of energy from geothermal resources at the candidate points will be calculated considering the output range of the power plants and associated uncertainties. System stability and reliability will be considered in investigating the most efficient transmission option for each scenario taking into account the optimum voltage level. PSS/E, Powerfactory and MatLab tools will be used to analyse the power system performance.

Network expansion plans of Powerlink in Queensland, specifically in Surat Basin and South Queensland are identified and will be considered in our current study. Preliminary simulations prove that compensation is crucial for long distance HVAC transmission lines to connect 500MW geothermal power plant located in Cooper Basin area to the Queensland network at Bulli area. Figure 17 illustrates transmission networks areas in Queensland. Bulli area is most likely the area for connecting future geothermal power from Innamincka. Currently active and reactive power losses calculations are being conducted using the power flow data of Queensland network.

The outputs of this study will include recommendations for the most efficient way of delivering the geothermal power to the best locations of the Australian NEM grid with optimum stability and reliability. This Program also addresses the challenging issue that not all expected geothermal power plants will become available at the same time. A multi-stage transmission expansion planning methodology will be developed to arrive at the most efficient network expansion solutions that will also deliver acceptable reliability at minimum cost.

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Industry Engagement

Centre research directions were endorsed by its industry, academic and government stakeholders in the first Stakeholders Workshop held in March 2010

Separate expert committees were set up to scrutinise the research objectives and project progress in each program area.

The Centre is engaged with the industry through the following mechanisms: • Stakeholders Workshops • Technical Advisory Committees • Australian Geothermal Energy Group • Australian Geothermal Energy Association

QGECE Stakeholders Workshop, March 2010 On 17 March 2010, the Queensland Geothermal Energy Centre of Excellence

(QGECE) held its first Stakeholders Workshop. The purpose of the Workshop was to present the Centre Research Program to the industry and other stakeholders; to demonstrate how the Centre is planning to add value to the development of the industry; and to form a basis for gaining industry feedback and bridging the gap between industry needs and our activities.

The attendance represented a good cross-section of the sector including: • the geothermal industry (18 delegates from 11 companies); • industry associations (three delegates from AGEA and Queensland

Resources Council); • service/consulting companies(13 delegates from seven companies); • research/academic community(31 delegates from UQ, Griffith

University and CSIRO); and • government(five delegates from QLD and SA)

The feedback from the delegates was positive. High expectations were expressed and the industry was almost unanimously enthusiastic about the Centre. Most of the Centre of research was strongly supported while there were also a number of suggestions on how things could be revised and improved.

The feedback from the Stakeholders Workshop was discussed at the QGECE Board Strategy Workshop in June affecting the Centre directions and the current projects.

Mobile Plant Focus Group Meeting Following the support given to the idea of a portable geothermal test plant at the

QGECE Stakeholders Workshop, a focus group meeting was organised to seek inputs on the critical parameters for such a project. The parameters established in this meeting form the basis of the design specifications for the portable test plant described earlier in the Power Conversion section.

Technical Advisory Committee Meetings Technical Advisory Committees were established in broad program areas. The

role of a Technical Advisory Committee (TAC) is to provide advice to the Director about the conduct of the Centre in a particular research area or a research project. The members of the TAC are expected to be people with relevant expertise nominated by the Director and approved by the Board. Written minutes are kept and these Minutes are presented to the QGECE Board. The current Technical Advisory Committee membership is Table 1.

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Table 2: Technical Advisory Committee Membership

Committee Area Membership

Reservoir Geology Richard Suttill, Origin Energy Behnam Talebi, Queensland Geological Surveys Doone Wyborn, Geodynamics Randall Cox, DERM David Champion, Geosciences Australia Graeme Beardsmore, Hot Dry Rocks Pty Ltd Scott Bryan, QUT Tonguc Uysal, QGECE Massimo Gasparon, QGECE

Power Conversion Allan Curtis, Principal Engineer - Thermal Generation, PB Stephen Hinchliffe, SKM Peter Schmidt, Geodynamics (until June 2010) Tony Roe, Geodynamics (after October 2010) Peter Jacobs, QGECE Kamel Hooman, QGECE Zhiqiang Guan, QGECE

Transmission Terry Miller, Manager Network Development, Powerlink Queensland Luke Falla, Senior Engineer, Australian Energy Market Operator Ltd Tapan Saha, QGECE Mehdi Eghbal, QGECE

The Centre is engaging with other universities and industry through the Australian geothermal Energy Group (AGEG) and Australian Geothermal Energy Association (AGEA)

Australian Geothermal Energy Group (AGEG) Australian Geothermal Energy Group (AGEG) is a national association of

individuals and companies with interest in geothermal energy. In 2009 AGEG incorporated and subsequently became an affiliate organisation with the International Geothermal Association. QGECE is an active member of the AGEG. The QGECE Director is a member of the AGEG Executive Committee; chairs the AGEG Technical Interest Group on Power Conversion (TIG 6); and has been serving as the Chair or Co-chair for the past three Australian Geothermal Energy Conferences.

Australian Geothermal Energy Association (AGEA) AGEA is the national industry association for the Australian Geothermal Energy

Industry. Since its establishment in 2007, AGEA has focused on building positive relationships with the Federal and State Governments and is ensuring that geothermal energy is promoted as an important and viable solution to Australia’s future energy security and to the reduction for greenhouse gas emissions.

Australia’s leading geothermal energy companies and service providers are members of the AGEA. The Queensland Geothermal Energy Centre of Excellence is an Associate Member of the AGEA.

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Education

The Centre is able to attract post-graduate students of highest calibre from around the world.

The Centre is actively involved in providing a geothermal energy training option for undergraduate and postgraduate students at the University of Queensland.

Undergraduate programs • Thesis Projects – Engineering students take a project course in their final year

at the University of Queensland. Over ten such thesis project topics were supervised last year by Centre staff.

• Honours Thesis Projects – One Honours student at the School of Earth Sciences was supervised and supported by the Centre for the project expenses

• Visiting lectures – The Centre staff is invited to energy-related undergraduate courses to deliver lectures on geothermal energy

• Design Project – Third year mechanical engineering design students designed a natural draft dry cooling tower in 2009; and an evaporator and a single-stage impulse expander in 2010.

The above activities help the university graduate engineers and scientists with exposure to geothermal energy sector and basic understanding of the issues involving geothermal energy utilisation.

Postgraduate Students The main involvement of the Centre in education area is post-graduate

education. The current list of QGECE PhD students are given in Table 2. Table 3: QGECE Post-graduate student list

Student Topic Commencement

A Atrens Supercritical CO2 Geothermal Siphon Mar-08 A Chumpia Metal Foam Heat Exchangers Mar-10 J Czapla Supercritical impulse turbine Nov-09 K N Hasan Power system reliability Mar-10 Y Lu Opportunities for improvement for dry cooling towers in geothermal plants Oct-10 V Marshall Queensland high heat producing granites Jan-10 C McClarren Queensland heat flow/geochemistry Jul-09 A Middleton Queensland fluid flow events Jan-10 H M Nguyen Power system stability Mar-09 M Odabaee Modelling metal foam heat exchangers May-09 M Sakhaei Scaled cooling tower tests in the laboratory Mar-10 R Singh Supercritical cycle control issues May-09 B Talebi Eastern Queensland Heat Flow regime and Geothermal Prospectivity Feb-10 B Twomey Mobile geothermal plant design/testing Apr-10 C Ventura Supercritical radial turbine Mar-09 J van Zyl Geochemistry of heat producing granites May-09

Z Zou Solar/Geothermal Tower Optimisation Mar-10

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Key Performance Indicators

Table 4 summarises the Centre performance against the Key Performance Indicators established in the Centre Agreement.

KPI Target over five

years

Current

Number of post-graduate students 12 17

Number of competitive research grants 5 4

Number of projects with industry funding 3 2

Number of refereed publications 40 35

Number of research projects undertaken in Queensland 8 2

The Centre started winning substantive competitive grants in its first year operation.

List of Competitive Grants 1. $26,000 for Z. Guan. Queensland International Fellowship – Renewable

Energy. Queensland State Government. 2. $204,000 for V Rudolph and K Hooman. Metal foam heat exchangers for dry

cooling. ANLEC R&D Research Grant. 3. $35,000 for K Hooman. Pathfinder grant for Air cooled metal foam heat

exchangers. UniQuest and Queensland Department of Employment, Economic Development & Innovation, $35,000; 2010.

4. $202,000 for K Hooman, A novel air-cooled fuel cell system, ARC DP Grant.

Projects with industry participation 1. Birdsville Geothermal Plant Expansion, H Gurgenci providing advice to

Ergon Energy on geothermal plant technology. 2. Supercritical turbine and cycle development with Verdicorp.

Number of research projects undertaken in Queensland 1. Birdsville Geothermal Plant Expansion, H Gurgenci providing advice to

Ergon Energy on geothermal plant technology. 2. Supercritical turbine and cycle development with Verdicorp.

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Financial Summary The total revenue and expenditure in the following table cover the period from the

beginning of the Centre (1 January 2009) until the end of the 2009/2010 Financial Year (30 June 2010).

Table 5: Revenue and Expenditure

Total Revenue $7,039,879

State Government Grant $7,000,000

Queensland International Fellowship $26,000

US Dept of Energy Reimbursement $13,879

Total Expenditure $2,446,765

Power Conversion Program $881,950

Heat Exchangers Program $335,241

Reservoir Geology Program $382,314

Transmission Program $205,562

Management $306,501

Infrastructure (lab refurbishment) $335,197

Carry Forward to 2009/2010 $4,593,114

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Publications

Refereed Journal Publications

Twenty-four refereed journal publications from Centre staff in 2009 and 2010 promote the standing of the Centre in the international scientific and engineering community

Atrens, A D, Gurgenci, H, Rudolph, V. (2010) Electricity generation using a carbon-dioxide thermosiphon. Geothermics, 39 2: 161-169.

Goh, Sheng How, dong, Zhao Yang and Saha, Tapan. (2009) An optimal strategy to maximise voltage stability using mimetic algorithms based on swarm trajectory movements. Australian Journal of Electrical and Electronics Engineering, 6 1: 21-32.

Golding, S D, Uysal, I T, Boreham, C J, Kirste, D, Baublys, K, and Esterle, J S, (2010) Adsorption and mineral trapping dominate CO2 storage in coal systems. Energy Procedia, (in press).

Hooman, K, Gurgenci, H, Dincer, I. (2009) Heatline and Energy-Flux-Vector Visualization of Natural Convection in a Porous Cavity Occupied by a Fluid with Temperature-Dependent Viscosity. Journal of Porous Media, 12 3: 265-275.

Hooman, K, Ejlali, A, Abdel-Jawad, M M. (2009) Hydrodynamic modeling of traffic jams in intracellular transport in axons. International Communications in Heat and Mass Transfer, 36: 329-334.

Hooman, K, Ejlali, A. (2010) Effects of viscous heating, fluid property variation, velocity slip, and temperature jump on convection through parallel plate and circular microchannels. International Communications in Heat and Mass Transfer, 37 1: 34-38.

Hooman, Kamel. (2010) Energy flux vectors as a new tool for convection visualization. International Journal of Numerical Methods for Heat and Fluid Flow, 20 2: 240-249.

Hooman, K, Gurgenci, H. (2010) Porous medium modeling of air-cooled condensers. Transport in Porous Media, 84 2: 257-273.

Hooman, K, Merrikh, A A. (2010) Theoretical analysis of natural convection in an enclosure filled with disconnected conducting square solid blocks. Transport in Porous Media, 85: 661-665.

Bagheri, GH, Mehrabian, M A, Hooman, K. (2010) Numerical investigation of transient behaviour of a PCM thermal storage module. In: Proceedings of the Institution of Mechanical Engineers Part A-Journal of Power and Energy, 224: 505-516.

Mutlu, Halim, Uysal, I. Tonguc, Altunel, Erhan, Karabacak, Volkan, Feng, Yuexing, Zhao, Jian-Xin and Atalay, Ozan (2010) Rb-Sr systematic of fault gouges from the North Anatolian Fault Zone (Turkey). Journal of Structural Geology, 32 2: 216-221.

Uysal, I T, Feng, Y, Zhao, Işik, V, Nuriel, P, Golding, S D. (2009). Hydrothermal CO2 degassing in seismically active zones during the late Quaternary. Chemical Geology, 265: 442-454.

Ejlali, A, Aminossadati, S M, Hooman, K, Beamish, B. (2009) A new criterion to design reactive coal stockpiles. International Communications in Heat and Mass Transfer, 36 7, 669-673.

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Ejlali, Azadeh, Ejlali, Arash, Hooman, Kamel, Gurgenci, Hal. (2009)

Application of high porosity metal foams as air-cooled heat exchangers to high heat load removal systems. International Communications in Heat and Mass Transfer, 36 7: 674-679.

Famouri, M, Hooman, K, Hooman, F. (2009) Effects of thermal boundary condition, fin size, spacing, tip clearance, and material on pressure drop, heat transfer, and entropy generation optimization for forced convection from a variable-height shrouded fin array. Heat Transfer Research, 40 3: 245-261.

Hooman, K, Hooman, F and Famouri, M. (2009) Scaling effects for flow in micro-channels: Variable property, viscous heating, velocity slip and temperature jump. International Communications in Heat and Mass Transfer, 36 2: 192-196.

Hooman, K. (2009) Slip flow forced convection in a microporous duct of rectangular cross-section. Applied Thermal Engineering, 29 5-6: 1012-1019.

Nuriel, P, Rosenbaum, G, Uysal, I T, Zhao, J-X, Golding, S D, Weinberger, R, Karabacak, V and Yoav, A. (2010). Formation of fault-related calcite precipitates and their implications for dating fault activity in the East Anatolian and Dead Sea fault zone. Geological Society of London, (in press).

Nuriel, P, Weinberger, R, Rosenbaum, G, Golding, S D, Zhao, J-X, Uysal, I T, Bar-Mathews, M, and Gross, M R (in review). (2010) Timing and mechanism of calcite-filled vein formation in convergent strike-slip setting with implications to the tectonic evolution of the Dead Sea fault. Earth and Planetary Science Letters.

Odabaee, M, Hooman, K, and Gurgenci, H. (2010) Metal foam heat exchangers for heat transfer augmentation from a cylinder in cross-flow. Transport in Porous Media, in press, 2010.

Uysal, I T, Gasparon, M, Bolhar, R, Zhao, J-x, Feng, Y-x., Jones, G Trace element composition of near-surface silica deposits – A powerful tool for detecting hydrothermal mineral and energy resources. Chemical Geology, 280 1-2: 154-169.

Uysal, I T, Feng, Y, Zhao, Bolhar, R, Işik, V, Baublys, K, Yago, A, and Golding, S D. (2010) Seismic cycles recorded in late Quaternary crack-seal veins: Geochronological and microchemical evidence. Earth and Planetary Science Letters in press.

Uysal, I T, Golding, S D, Bolhar, R, Zhao, J-X, Feng, Y, Greig, A, Baublys, K, Esterle, J S. (2010) CO2 degassing and trapping during hydrothermal cycles related to Gondwana rifting in eastern Australia. Submitted to: Contributions to Mineralogy and Petrology.

Tamayol, A, Hooman, K, Bahrami, M. (2010) Thermal analysis of flow in a porous medium over a permeable stretching porous wall. Transport in Porous Media, 85: 641-676.

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Refereed Conference Proceedings

Eleven papers in refereed conference proceedings in 2009 and 2010 show that the Centre staff are engaged with the international scientific and engineering community at the highest levels

Atrens, A D, Gurgenci, H, Rudolph, V. (2010) Economic analysis of a CO2 thermosiphon”. World Geothermal Congress, Bali, Indonesia.

Gurgenci, H and Guan, Z. (2009) Dirigible natural draft cooling tower in geothermal and solar power plant applications. In: 14th IAHR Cooling Tower and Air-Cooled Heat Exchanger Conference, Stellenbosch, South Africa, (1-4), 1-3 December 2009.

Dahal, S, Mithulananthan, N and Saha, T K. (2010) Investigation of Small Signal Stability of a Renewable Energy based Electricity Distribution System. In: IEEE PES General Meeting. IEEE Power and Energy Society General Meeting, Minneapolis, MN. (1-8), 25-29 July 2010.

Ekabayaje, Chandima, Saha, Tapan K, Ma, Hui and Allan, David. (2010) Application of Polarization Based Measurement Techniques for Diagnosis of Field Transformers. In: IEEE PES General Meeting. IEEE Power and Energy Society General Meeting, Minneapolis, MN. (1-8), 25-29 July 2010.

Fonseka, P A J, Dong, Z Y and Saha, T K. (2009) A performance comparison of probabilistic techniques for electricity market simulation. In: Proceedings of the IEEE Power and Energy Society (PES) 2009 General Meeting. IEEE Power and Energy Society (PES) General Meeting, Calgary, Alberta, Canada (1-7), 26-30 July 2009.

Hooman, K, Gurgenci, H. (2010) Different heat exchanger options for natural draft cooling towers. World Geothermal Congress, Bali, Indonesia.

Nappu, M B and Saha, T K. (2009) A comprehensive tool for congestion-based nodal price modelling. In: Proceedings of the IEEE Power and Energy Society (PES) 2009 General Meeting. IEE Power and Energy Society (PES) General Meeting, Calgary, Alberta, Canada (1-8), 26-30 July 2009.

Nguyen, Mai Huong, Saha, Tapan K and Mehdi Eghbal. (2010) A Comparative Study of Voltage Stability for Long Distance HVAC and HVDC Interconnections. In: Proceedings of 2010 IEEE PES General Meeting, July 26 - 29, 2010, Minneapolis, Minnesota, USA.

Odabaee, M and Hooman, K. (2010) Entropy-energy analysis of metal foam heat exchangers as air-cooled heat exchangers. In: The 3rd International Conference on Porous Media and its Applications in Science and Engineering, ICPM3, June 20-25, 2010, Montecatini, Italy.

Saha, T K, Middleton, R and Thomas, A. (2009) Understanding frequency and time domain polarisation methods for the insulation condition assessment of power transformers. In: Proceedings of the IEEE Power and Energy Society (PES) 2009 General Meeting. IEE Power and Energy Society (PES) General Meeting, Calgary, Alberta, Canada (1-8), 26-30 July 2009.

Tanimizu, K, Hooman, K. (2010) Scaling laws for a natural draft cooling tower: Porous medium modeling of the heat exchangers. In: 3nd International Conference on Porous Media and its Applications in Science and Engineering 2010.

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Other Conference Presentations

An impressive range of industry conference presentations show how the Centre is actively interacting with the industry professionals

Atputharajah, Arulampalam and Saha, Tapan K. (2009) Power System Blackouts. In: Proceedings of the Fourth International Conference on Industrial and Information Systems. Fourth International Conference on Industrial and Information Systems, Peradeniya, Sri Lanka (460-465) 28-31 December 2009.

Atrens, A D, Gurgenci, H, Rudolph, V. (2009) Exegetic performance and power conversion of a CO2 thermosiphon. (2009) Australian Geothermal Energy Conference, Brisbane, Australia.

Atrens, Aleks, Gurgenci, Hal and Rudolph, Victor (2009). Energy analysis of a CO2 Thermosiphon. In: Proceedings, Thirty-Fourth Workshop on Geothermal Reservoir Engineering. 34 Workshop on Geothermal Reservoir Engineering, Stanford University, CA, USA, (1-8). February 9-11, 2009. Dahl, Sudarshan, Kataoka, Yoshiko, Attaviriyanupap, Pathom and Saha, Tapan K. (2009) Effects of induction machines dynamics on power system stability. In; AUPEC ’09. 19TH Australasian Universities Power Engineering Conference: Sustainable energy Technologies and Systems, Adelaide, Australia (1-6) 27-30 September 2009.

Dahl, Sudarshan, Kataoka, Yoshihiko, Attaviriyanupap, Pathom and, Saha, Tapan K. (2009) Effects of induction machines dynamics on power system stability. In: AUPEC ’09. 19th Australasian Universities Power Engineering Conference: Sustainable Energy Technologies and Systems, Adelaide, Australia (1-6) 27-30 September 2009.

Eghbal, Mehdi, Saha, Tapan K and Nguyen, Mai H. (2010) Optimal Voltage Level and Line Bundling for Transmission lines. Accepted for publication in: Proceedings of AUPEC. Australasian Universities Power Engineering Conference, New Zealand, 5-8 December 2010.

Ejlali, A, Aminossadati, S M, Hooman, K, Beamish, B. (2009) Side Angle Optimisation of Coal Stockpiles. In: 2009 Australian Mining Technology Conference.

Glikson, A Y and Uysal, I T, (2010), Australian Geothermal Conference 2010.

Golding, Suzanne D, Uysal, Ibrahim T, Boreham, C, Kirste, D, Esterle, Joan S, (2009), Adsorption and mineral trapping in coal systems. In: CO2CRC Research Symposium 2009, 1-3 December 2009, (89-89), Sunshine Coast, Qld Australia.

Golding, S D, Uysal, I T, Boreham, C, Kirste, D, Esterle, Joan S, (2009) Implications of natural analogue studies for CO2. In: Proceedings of 2009 Asia Pacific Coalbed Methane Symposium and 2009 Coalbed Methane symposium, Xuzhou, Jiangsu, China, 24-26 September 2009: 712-725.

Gurgenci, Hal (2009). Electricity generation using a supercritical CO2 Geothermal Siphon. In: Proceedings, Thirty-Fourth Workshop on Geothermal Reservoir Engineering. 34 Workshop on Geothermal Reservoir Engineering, Stanford University, CA, USA, (1-8). February 9-11, 2009.

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Nappu, Muhammad Bachtar, Saha, Tapan K and Arief, Ardiaty. (2009) Analysis of the influence of transmission congestion on power market based on LMP-lossless model. In: AUPEC ’09. 19th Australasian Universities Power Engineering Conference: Sustainable Energy Technologies and systems, Adelaide, Australia (1-6) 27-30 September 2009.

Nguyen, Mai H, Saha, Tapan K, and Eghbal, Mehdi (2010) Impacts of HVAC Interconnection Parameters on Inter-area Oscillation. Accepted for publication in: Proceedings of AUPEC 2010. Australasian Universities Power Engineering Conference, New Zealand, 5-8 December 2010.

Nguyen, Mai Huong, Saha, Tapan K. (2009) Power loss evaluation for long distance transmission lines. In: Geothermal Downunder. Clear energy from the ground up. 2009 Geothermal Energy Conference and Trade Show, Brisbane, Qld, Australia (1-6). 10-13 November 2009.

Odabaee, M, Hooman, K, and Gurgenci, H. (2009) Comparing the Tube Fin Heat Exchangers to Metal foam Heat Exchangers for Geothermal Applications. In: Geothermal Downunder. Clear energy from the ground up. 2009 Geothermal Energy Conference and Trade Show, Brisbane, Qld, Australia. 10-13 November 2009.

Ventura, Carlos, Sauret, Emilie, Jacobs, Peter, Petrie-Repar, Paul, Gollan, Rowan and van der Laan, Paul, (2010), Adaption and use of a compressible flow solver for turbomachinery design. In: V European Conference on Computational Fluid Dynamics ECCOMAS CFD 2010, Editors: Pereira, J C F and Sequeira, A.

Reports

P A Jacobs, R J Gollan, A J Denman, B T O'Flaherty, D F Potter, P J Petrie-Repar and I A Johnston (2010), Eilmer’s Theory Book: Basic Models for Gas Dynamics and Thermochemistry. Mechanical Engineering Report 2010/09, The University of Queensland.

P A Jacobs, and R J Gollan, (2010 revisions) The Eilmer3 Code: User Guide and Example Book. Mechanical Engineering Report 2008/07, The University of Queensland.

Rowlands A S, Jacobs, P J, Singh R (2010) Modbus RTU Compatible Multichannel Data Acquisition & Control System. Mechanical Engineering Research Report 2010/02, The University of Queensland.