This paper is comprised of three sections and outlines the outcome achieved from instituting an effective preventative maintenance program; specifically, highlighting a steam surface condenser application that was originally equipped with a stainless-steel metal bellows type expansion joint system. In the first section of the paper, a general overview of steam inlet type expansion joint systems will be presented to provide an understanding of the specific application, typical design parameters and conditions, system components, varying expansion joint designs, configurations, and installation methodologies. The second section will outline types of inspections that typically support preventative maintenance programs within the power generation industry. Lastly, the case study will examine the account of an actual project and the practice of implementing a preventative maintenance program; outlining inspection types, how those measures supported a root cause analysis, and ultimately developing a unique solution to address the issues identified during subsequent inspections and analyses. The case study focuses on developing a retrofitted rubber ‘dog bone’ expansion joint system to replace the failed metal bellows expansion joint. Various points within the overall project life cycle will be reviewed; from the point of initial inspection that identified the root cause and defined loss in performance, evaluation and engineering to support the replacement design, onsite execution and installation methodology, and post-maintenance testing and operation.

Worldwide energy consumption is accelerating at an unprecedented rate while humanity comes to understand the effects of climate change. Renewable resources such as wind and solar supply more energy every year, but the overwhelming majority of energy consumed is still from fossil fuels. The transition to zero carbon emission sources is important, but carbon negative energy could also become necessary in ensuring a sustainable global environment and economy. The most technically and commercially viable carbon negative solution is biomass-fueled power generation with carbon capture and sequestration. A conceptual design based on a biomass-fired circulating fluidized-bed boiler and developed using the Thermoflex software package (Thermoflow, Inc.) is presented that can be evaluated and pursued by the research, engineering, and business communities. Recommendations are proposed for siting and fuel supply in the Southeastern U.S., with an evaluation of some of the impacts from wood harvesting, processing, and transportation to the lifecycle carbon emissions. An economic analysis of this carbon negative concept indicates that certain policy proposals in the U.S. could make biomass power generation with carbon capture and sequestration an economically feasible resource. Results show that an owner and/or the public could realize a net benefit of up to $332/MWh above and beyond marginal energy or capacity values under aggressive carbon pricing.

Micro combustion and power generation systems have increasingly been investigated as potential alternatives to electrochemical energy storage thanks to hydrocarbon fuel’s high energy density, but electrical componentry for pumping significantly limits the overall system efficiency. These components must be eliminated to allow for widespread adoption of micro combustion and power generation systems, and so the development of an alternative pumping technique is required. By taking advantage of the thermal transpiration phenomenon, small-scale pumping can be obtained in the presence of a temperature gradient. Initial work has been done to investigate the efficacy of this system, but a major issue has arisen due to the lack of low-cost thermal transpiration membranes with desirable pore characteristics. Research has revealed that vessel hyphae present in the roots of mushrooms (mycelium) form a network which could meet the requirements of an effective thermal transpiration membrane. Proper growing conditions could also allow for an application specific mycelium structure providing a highly effective and low-cost thermal transpiration membrane for micro combustion systems.

Many parts of the world are facing the triple challenge of providing secure energy to fuel economic growth at an affordable cost while minimizing the impact of energy production on the environment. Island nations especially struggle to address this trilemma, as renewable resources are usually limited and fossil fuels imported. Traditionally such distributed power plants have relied on liquid fuels and multiple open cycle reciprocating engines to provide both redundancy and the ability to load follow across a broad load range to maximize efficiency. This approach has created high electricity prices and significant negative environmental impact, especially that attributed to CO 2 , NO x , and SO x . With increasing natural gas production, the availability of Liquefied Petroleum Gas (LPG) has grown, and costs have fallen, allowing the potential to switch from fuel oils to LPG to reduce environmental impacts. Energy costs and environmental impact can be further reduced by using high efficiency Gas Turbine Combined Cycle plants with dry low emissions combustion technology. However, a further hurdle facing many locations is lack of the fresh water required for combined cycle operations. LPG-fuelled Gas Turbine Combined Cycle using Organic Rankine Cycle (ORC) technology can address all aspects of this energy trilemma. This paper reviews the conceptual design of a proposed 100MW distributed power plant for an island location, based on multiple LPG-fuelled gas turbines to follow load demand, with an ORC bottoming cycle to maximize efficiency.

This work addresses the strategy of AES Corporation (AES Chivor) in order to extend the life of La Esmeralda reservoir to support Colombia’s future energy demand. Chivor Hydropower Plant entered into service in 1978 and has a capacity of 1000 MW, 8 % of Colombia’s demand. It is first described how the Colombian electricity energy mix is composed. Then, La Esmeralda reservoir, which is used by Chivor for power generation, is described; sediment management plans and maintenance costs for equipment and infrastructure are addressed. Then, sediment dynamics studies that have been done in order to determine life expectancy of La Esmeralda reservoir are listed. Such studies have been used to execute the Chivor’s Life Extension Project, which considers the modification of intakes as the best option to extend the life of the reservoir for at least 50 years, among several alternatives that were evaluated by a panel of international experts. This represents a challenge from the engineering point of view, and the project will be shown as a successful example for a country with such dependence on hydropower generation. Modernizing existing infrastructure without affecting the operation, as in this case, is crucial to show how a sustainable sediment management plan and technological development are necessary to extend life of hydropower generation projects, and to help meeting energy demand in a sustainable way for countries such as Colombia with a growing economy.

Lean-premixed (LPM) gas turbines have been developed for stationary power generation in efforts to reduce emissions due to strict air quality standards. Lean-premixed operation is beneficial as it reduces combustor temperatures, thus decreasing NO x formation and unburned hydrocarbons. However, tradeoffs occur between system performance and turbine emissions. Efforts to minimize tradeoffs between stability and emissions include the addition of hydrogen to natural gas, a common fuel used in stationary gas turbines. The addition of hydrogen is promising for both increasing combustor stability and further reducing emissions because of its wide flammability limits allowing for lower temperature operation, and lack of carbon molecules. Other efforts to increase gas turbine stability include the usage of a non-lean pilot flame to assist in stabilizing the main flame. By varying fuel composition for both the main and piloted flows of a gas turbine combustor, the effect of hydrogen addition on performance and emissions can be systematically evaluated. In the present work, computational fluid dynamics (CFD) and chemical reactor networks (CRN) are created to evaluate stability (LBO) and emissions of a gas turbine combustor by utilizing fuel and flow rate conditions from former hydrogen and natural gas experimental results. With CFD and CRN analysis, the optimization of parameters between fuel composition and main/pilot flow splits can provide feedback for minimizing pollutants while increasing stability limits. The results from both the gas turbine model and former experimental results can guide future gas turbine operation and design.

The Colombian electricity sector is mainly composed of hydropower plants covering up to 70% of the total power generation. Several alternatives had been evaluated to complement Colombian’s energy mix, including solar PV and wind energy plants; however, there is no consensus about the appropriate solution in terms of the available resource, energy demand, and energy mix complementing. This work presents the performance evaluation of a hybrid thermosolar power plant at a city on the Caribbean Colombian coast, considering local environmental conditions such as ambient temperature and solar resource availability to attain the factor that constrain its optimal operating conditions. The overall energy and exergy plant efficiency is analyzed, considering an arbitrary number of stages. For instance, comparing a single-stage plant running with air with a two compression stages with inter-cooling and two expansion stages with reheating, the results indicate a 30 % higher exergy efficiency, and overall energy efficiency about 32 % larger and a fuel conversion rate around 18 % larger.

The power generation industry has a major role to play in reducing global greenhouse gas emissions, and carbon dioxide (CO 2 ) in particular. There are two ways to reduce CO 2 emissions from power generation: improved conversion efficiency of fuel into electrical energy, and switching to lower carbon content fuels. Gas turbine generator sets, whether in open cycle, combined cycle or cogeneration configuration, offer some of the highest efficiencies possible across a wide range of power outputs. With natural gas, the fossil fuel with the lowest carbon content, as the primary fuel, they produce among the lowest CO 2 emissions per kWh generated. It is possible though to decarbonize power generation further by using the fuel flexibility of the gas turbine to fully or partially displace natural gas used with hydrogen. As hydrogen is a zero carbon fuel, it offers the opportunity for gas turbines to produce zero carbon electricity. As an energy carrier, hydrogen is an ideal candidate for long-term or seasonal storage of renewable energy, while the gas turbine is an enabler for a zero carbon power generation economy. Hydrogen, while the most abundant element in the Universe, does not exist in its elemental state in nature, and producing hydrogen is an energy-intensive process. This paper looks at the different methods by which hydrogen can be produced, the impact on CO 2 emissions from power generation by using pure hydrogen or hydrogen/natural gas blends, and how the economics of power generation using hydrogen compare with today’s state of the art technologies and carbon capture. This paper also addresses the issues surrounding the combustion of hydrogen in gas turbines, historical experience of gas turbines operating on high hydrogen fuels, and examines future developments to optimize combustion emissions.

Significant research is ongoing on several fronts in smart sensor technologies for optimizing the performance of power generating assets. The initiatives include: 1. Real-time models with advanced computational algorithms, embedded intelligence at sensor and component level for reducing operating costs, improving efficiencies, and lowering emissions. 2. Optical sapphire sensors for monitoring operation and performance of critical components in harsh environments, for improving accuracy of measurements in combustion monitoring, and lowering operating costs. 3. Wireless technologies using (a) microwave acoustic sensors for real-time monitoring of equipment in high temperature/pressure environments (b) integrated gas/temperature acoustic sensors for combustion monitoring in diverse harsh environment locations to improve combustion efficiency, reduce emissions, and lower maintenance costs (c) sensors for sensing temperature, strain and soot accumulation inside coal-fired boilers for detailed condition monitoring, better understanding of combustion and heat exchange processes, improved designs, more efficient operation. 4. Distributed optical fiber sensing system for real-time monitoring and optimization of high temperature profiles for improving efficiency and lowering emissions. 5. Smart parts with embedded sensors for in situ monitoring of multiple parameters in existing and new facilities. 6. Optimizing advanced 3D manufacturing processes for embedded sensors in components for harsh environments to reduce costs and improve efficiency of power generation facilities with carbon capture capabilities. 7. New energy-harvesting materials for powering wireless sensors in harsh environments, improving reliability of wireless sensors in demanding environments, and in-situ monitoring and performance of devices and systems. 8. Real-time, accurate and reliable monitoring of temperature at distributed locations of sensors in harsh environments for improving operations and reducing operating costs. 9. Algorithms and methodologies for designing control systems utilizing distributed intelligence for optimal control of power generation facilities. 10. Gas sensors for monitoring high temperatures in harsh environments for lowering operating costs and better control of operations. 11. Optimizing placement of smart sensors in networks for cognitive behavior and self-learning. This paper provides an overview of the initiatives in smart sensor technologies and their applications in optimizing the performance of power generating facilities.

This paper makes the energy consumption difference analysis of the key parameters variations of a 1000MW Ultra-Supercritical Double Reheat coal-fired power generation system. By applying the constant power variable condition calculation method for the steam turbine thermal system, the energy consumption difference analysis mode is established. The energy consumption difference of the key parameters variations (such as the main steam pressure, the main steam temperature and the exhaust steam pressure) of a 1000MW ultra-supercritical double reheat coal-fired power generation system at THA load, 75%THA load, 50%THA load and 40%THA load are investigated. The effects of the key parameter changes on the gross turbine heat rate and coal consumption rate at different working conditions are analyzed, as well as the corresponding energy consumption variation characteristic curves, and the variation rules of power generation efficiency are explored. In addition, the energy consumption difference variation rules of system at different working conditions are studied when any two key parameters such as the main steam temperature, main steam pressure, and the exhaust pressure change simultaneously. The research results show that within a certain range of variation, when the main steam temperature or the main steam pressure increase, or the exhaust gas pressure decreases, the energy consumption of the overall system drops. And with the reduction of load, the main steam temperature has the greatest influence on the coal consumption. By studying the effects of the simultaneous change of two key parameters on the energy consumption of the overall system, it is found that under the same load, the change of the exhaust gas pressure has the greatest influence on the system energy consumption. This paper will provide the theoretical guidance for the energy-saving diagnosis and operation optimization of ultra-supercritical double reheat coal-fired power generation system.

Understanding the thermodynamics associated with ion mixing and separation processes is important in order to meet the rising demands for clean energy and water production. Several electrochemical-based technologies such as capacitive deionization and capacitive mixing (CapMix) are capable of achieving desalination and energy production through ion mixing and separation processes, yet experimental investigations suggest energy conversion occurs with low second law (thermodynamic) efficiency. Here, we explore the maximum attainable efficiency for different CapMix cycles to investigate the impact cycle operation has on energy extraction. All investigated cycles are analogous to well documented heat engine cycles. In order to analyze CapMix cycles, we develop a physics-based model of the electric double layer based on the Gouy-Chapman-Stern theory. Evaluating CapMix cycles for energy generation revealed that cycles where ion mixing occurs at constant concentration and switching occurs at constant charge (a cycle analogous to the Stirling engine) attained the highest overall first law (electrical energy) efficiency (39%). This first law efficiency is nearly 300% greater than the first law efficiency of the Otto, Diesel, Brayton, and Atkinson analog cycles where ion mixing occurs while maintaining a constant number of ions. Additionally, the maximum first law efficiency was 89% with a maximum work output of 0.5 kWh per m 3 of solution mixed (V = 1.0V) using this same Stirling cycle. Here the salinity gradient was C H = 600 mM and C L = 1 mM (ΔG mix = 0.56 kWh/m 3 ). The effect of voltage was also examined at C H = 600 mM (seawater) and C L = 20 mM (river water). CapMix cycles operated at lower voltage (V < 1.0V), resulted in the Otto cycle yielding the highest first law efficiency of approximately 25% (compared to under 20% for the Stirling cycle); however, this was at the expense of a reduction (50x) in net electrical energy extracted from the same mixing process (0.01 kWh per m 3 ).

Development of alternative carbonaceous sources for energy production is essential to alleviate the dependence on depleting fossil fuels which led to increasing atmospheric CO 2 and thus global warming. While biomass utilization for energy and chemical production has been extensively studied in the literature, such studies on municipal solid wastes is difficult to interpret due to the heterogeneous nature of the waste. Understanding of the influence of individual components is necessary for comprehensive development of waste-to-energy pathway. One such waste that is complicated and has often been ignored in the literature is composite polymer absorbent material waste which can also be considered as a potential feedstock for thermochemical pathway of energy production. Composite polymer absorbent materials are ubiquitously used these days in the form of sanitary napkins, diapers, water blockers, fire blockers and surgical pads due to their high water-absorptive nature. Pyrolysis and CO 2 gasification is ideal for such materials due to its versatile feedstock intake and uniform product output in the form of syngas with adjustable composition. CO 2 gasification also provides the added benefit of CO 2 utilization which provides carbon offset to this process. In the present study, a mixture of cellulose, absorbent material (sodium polyacrylate), polypropylene and polystyrene in a fixed proportion, to model approximate composition of a diaper, was examined for its pyrolysis and CO 2 gasification capability for viable syngas production. The influence of individual components into the syngas yield from the composite waste gasification was also investigated. A fixed-bed, semi-batch reactor facility along with gas chromatography was employed to analyse the syngas yield and compositional evolution. Pyrolysis was done under nitrogen atmosphere and gasification was done under CO 2 atmosphere. CO 2 gasification provided net CO 2 consumption which means a net reduction in carbon emissions per joule of energy produced. The sample was tested under four isothermal conditions of 973, 1073, and 1173 K to understand the impact of operational conditions on the syngas yield. Influence of individual component of the composite absorbent waste on the syngas yield and composition was also analyzed by comparing these syngas characteristics with that of the yield from gasification of its individual components separately at 1173 K. These investigations provided us with novel results on the behavior and capabilities of these composite polymer absorbent wastes and which opens up a new avenue towards efficient utilization of solid waste resources for sustainable energy production in the form of syngas which can also be used for various chemicals production such as methanol, gasoline and other petrochemical products.

Due to Florida’s unique location as a peninsula as well as it’s oblong shape, it is difficult as a state to be connected the grid of the rest of the United States. As a result, Florida has many utility companies providing power to the region. The integrated resource plans of these utility companies were reviewed looking at the projects and plans they expect to undertake in the next decade. In recent years, use of fossil-fuel fired power production has been declining as the cost of using renewable sources has become more affordable. This shift towards renewables was evident when reviewing the integrated resource plans. An unexpected consequence of using renewable energy is how it will affect the individuals living near the energy production. Issues this paper will examine include the expected change of Florida’s current and future energy mix as well as how this change will affect the health of those living in the vicinity. A review of various power providers in the state of Florida will be conducted through a review of their integrated resource plans and other research data. The co-authors are a mechanical engineering student and a graduate public health student.

Renewable energy has a significant role to play in helping the world achieve the greenhouse gas emission reduction necessary to achieve the pathway to a 2°C increase in global temperature. Electricity generation from wind and solar resources can contribute immensely to the decarbonization of power generation, but these resources are intermittent. High penetration of intermittent renewable power generation can cause grid stability and control issues for network operators, with fast response fossil fuel power plant necessary to provide security of supply and maintain grid stability. Increasingly natural gas-fueled distributed power generation is being installed to provide the necessary grid support. However, hybrid power plants comprised of a fossil fuel power generating system, a renewable power generation system and energy storage can provide both the low CO 2 electricity required to meet environmental constraints, and the despatchability and stability required by grid operators. Integrated Solar Combined Cycle Power Plants (ISCCs), comprising a Concentrated Solar Power plant and a natural gas fired combined cycle plant, have the potential to simultaneously reduce fossil fuel consumption, provide secure, highly predictable electricity generation, and reduce the cost of integrating renewable energy into a power system. While a number of ISCCs have been built at a larger scale (above 150MW power output), the concept has rarely been adopted for smaller scale distributed power applications. In addition, the traditional ISCC concept uses a steam bottoming cycle, which consumes water, and often locations where distributed ISCC could be utilized suffer from a scarcity of fresh water. This paper evaluates whether replacing the steam bottoming cycle with an Organic Rankine Cycle (ORC) alternative can provide a simpler, lower cost distributed ISCC solution that can be utilized on smaller and island grid systems, or mini- and micro-grids, to provide an affordable, water-free, low carbon power generation system.

In order to pursue superior cycle efficiency and lower power generation cost for the CSP plants, two S-CO 2 –Brayton–cycle–based power cycles with different utilization methods of the residual heat recover of the top S-CO 2 Brayton cycle (SCBC) are investigated to seek alternatives to the stand-alone S-CO 2 cycle as the power block of concentrated solar power plants. The residual heat released by the top S-CO 2 cycle are either utilized to drive a LiBr absorption chiller (AC) for further chilling of the CO 2 fluids exiting the precooler before entering the main compressor inlet temperature or recovered by an organic rankine cycle (ORC) for generating electricity. Thermo-economic analysis and optimization are performed for the SCBC–AC and SCBC–ORC, respectively. The results show that the thermal and exergetic efficiencies of the SCBC–AC are comparable with those of the SCBC–ORC in low pressure ratio conditions ( PR <2.7) but are apparently lower than SCBC–ORC when PR is over 2.7. The LCOE of the CSP plant integrated with SCBC–AC is more sensitive to the change of PR . The optimal PR to maximum the cycle efficiency or minimize the plant LCOE for the SCBC–ORC is higher than that for the SCBC–AC, while the optimal recuperator effectiveness to minimize the LCOE of CSP plant integrated with SCBC–ORC is lower than that of SCBC–AC. The optimization results show that the thermo-economic performance of the SCBC–AC is comparable to that of the SCBC–ORC. Significant η ex improvement and LCOE reduction can be obtained by both the two combined cycles relative to the stand-alone S-CO 2 cycle. The maximal η ex improvements obtained by the SCBC–ORC and SCBC–AC are 6.83% and 4.12%, respectively. The maximal LCOE reduction obtained by the SCBC-ORC and SCBC–AC are 0.70 ȼ / (kW·h) and 0.60 ȼ / (kW·h), respectively.

The method of specific entropy generation (SEG) is employed to show how the thermal efficiency of a combined cycle power plant can be improved. SEG is defined as the total entropy generation rate associated with the operation of a power plant per unit flowrate of the fuel burnt in the combustor. In a recent article published in Journal of Energy Resources and Technology, it is shown that the thermal efficiency of a gas turbine cycle inversely correlates with SEG. In this work, we extend the analysis to show that the same relation between the thermal efficiency and SEG is also valid for a combined cycle. The topping cycle consists of a compressor, a combustor and a gas turbine, whereas the bottoming cycle includes a heat recovery steam generator, a steam turbine, a condenser, a deaerator, a condensate pump and a feed water pump. It is shown that the minimization of SEG is identical to the maximization of thermal efficiency. An illustrative example is presented using the SEG method to improve the efficiency of the combined cycle. The results reveal that 89% of the inefficiencies takes place in the gas turbine cycle. A modified design is then proposed to reduce the efficiency losses in the topping cycle. In the modified design, the thermal energy of the flue gases is first used in a heat exchanger to preheat the air before the combustor. The flue gases leaving the heat exchanger is then directed to the HRSG for producing steam. With this modification, the thermal efficiency and the power output of the combined cycle increase 2.7 percentage points and 20.9 kW per unit molar flowrate of the fuel. Recovering the thermal energy of the flue gases for both preheating the air and producing the steam appears to be more efficient than just producing the steam. Despite the net power production of the bottoming cycle decreases in the modified design, the overall efficiency of the combined cycle increases due to the improvement in the efficiency of the topping cycle.

In this paper, a numerical simulation of three-dimensional motion of tether undersea kites (TUSK) for power generation is studied. TUSK systems includes a rigid-winged kite, or glider, moving in an ocean current in which a tethered kite is connected by a flexible tether to a fixed structure. Kite hydrodynamic forces are transmitted through the tether to an electrical generator on the fixed structure. The numerical simulation models the flow field in a three-dimensional domain near the rigid undersea kite wing by solving the full Navier-Stokes equations. In order to resolve the boundary layer near the kite surface, adequate grid resolution is needed which increases the computational run time drastically especially in 3D simulations. Therefore, in this study a slip boundary condition is implemented at the kite interface to accurately predict the total drag, with lower grid resolution. In order to reduce the numerical run times, a moving computational domain method is also used. A PID controller is used to adjuste the kite pitch, roll and yaw angles during power (tether reel-out) and retraction (reel-in) phases. A baseline simulation study of a full-scale TUSK system is conducted in which the expected cross-current, figure-8 motions during a kite reel-out phase is captured. The effect of the tether drag on the kite motion and resulting power output is also investigated and compared with the results of the baseline simulation.

Development of alternative, clean and renewable energy production from different hydrocarbon materials helps to partially replace the limited resources of fossil fuels and also help reduce carbon emissions from fossil fuels that drives global warming. Biomass and bio-wastes are renewable and sustainable hydrocarbon resources, which can be used for energy and fuels production along with permanent disposal of plastic wastes. Landfills of wastes is unsustainable with additional problems of non-degradability and growing burden to the environment and society. Co-pyrolysis and co-gasification of biomass with different types of plastic wastes has shown to provide enhanced product yields and quality for syngas and liquid fuel production. To date, limited information is available on the understanding of chars produced from co-pyrolysis. The effect of co-pyrolysis on the type, quality and yield of chars produced is essential for efficient utilization of a wide variety of biomass, bio-waste and plastic waste resources. This paper provides information on the effect of plastic addition to the pyrolysis of biomass as well as the quality and quantity of char produced with different amounts of plastic waste added at different pyrolysis temperatures. TGA reactor was used for all these investigations and the quality of char produced was examined from the perspective of char combustion for energy production. Char is commonly produced as a by-product from pyrolysis and gasification reactors. Carbonization temperatures investigated were in the range of 573–773 K for 30 min using pinewood biomass, while recycled polyethylene terephthalate was used as plastic waste. The investigations revealed that chars produced from co-pyrolysis especially for carbonization temperature (T c ) of 673 K and above behaved completely differently than the chars produced from separate pyrolysis of biomass and plastic waste under the same pyrolysis conditions. These chars produced from co-pyrolysis were more uniform in their behavior in oxidation environment, with higher heat flow for almost similar quantities of chars during oxidation. This was conjectured to be from enhanced quality of chars produced having increased C content (from increased heavy aromatics and efficient loss of volatiles) during co-pyrolysis without any loss of char yield. The char yield was found to be equal or higher during co-pyrolysis compared to the weighted aggregate of individual pyrolysis. These investigations provided novel results on the behavior and capabilities of chars produced from co-pyrolysis of biomass and plastic wastes to provide a new avenue for the quality enhancement of bio-chars and efficient utilization of carbonaceous solid waste resources.

With the everlasting increase in the population, a huge surge in the electricity consumption can be noticed. Thus, the power and electricity generating power plants need to augment their performance to cope with this uprising problem. The main goal for most gas turbine power plants is to increase their efficiency and performance which can be achieved by increasing the turbine inlet temperature (TIT). However, increasing the TIT requires cooling of the turbine blades to extend its lifetime and avoid thermal stresses and oxidation rates. Usually, there are two routes to improve the turbine blade cooling, either scientist focus on the parameters that effect the cooling process such as the film cooling effectiveness, shape of holes and angle of injection, or the problem is approached from a thermodynamic point of view. It is well known that the air used to cool the turbine blades is bled from the compressor which causes a severe penalty on the thermodynamic efficiency and power output of the gas turbine. This paper main objective is to improve the gas turbine performance by lowering the temperature of the coolant lines bled from the compressor for turbine blade cooling resulting in a reduction in the amount of coolant mass flow rate required for turbine cooling which will reduce the penalty on the overall efficiency increasing it. For this purpose, three different configurations of Maisotsenko desiccant cooling systems were proposed to cool down coolant lines as well as the inlet air temperature. Optimization analysis was performed to determine the best operating parameters of the gas turbine as well as the cooling systems. Sensitivity analysis was conducted as well to investigate the effect of various variables on the gas turbine overall efficiency and the coolant mass flow rate. The results showed an increase in the overall efficiency from 42.57% to 43.83%, reduction in the amount of coolant mass flow rate that is bled from the compressor from 4.584 kg/s to 3.607 kg/s and in the cooling fraction from 4.72% to 3.9%.

Traditionally, water is used in thermal power plant for heat rejection processes such as in the steam condenser for use in a Rankine cycle. Typically, research has shown that approximately 2 litres of water are required to generate 1 kWh of electricity on a wet-cooling system; which on a bigger scale could translated to more than 11000000 m 3 per year of make-up water for a 600 MWe coal-fired plant. The ever-increasing cost of water resources as well as the water resource scarcity have paved a path to dry-cooling systems which alternatively provide a significant cooling potential. However, dry-cooling systems performance are generally driven by the atmospheric conditions which at time do not meet the desired cooling temperatures resulting in significant drop in their performance. Recent developments in cooling technology suggest that hybrid systems (dry-wet) be used to insure good and manageable performances while maintaining the cost of operation at admissible range. In light of the recent draught experienced in South Africa, attention was drawn to evaluation of deluged systems performance as well as water consumption to increase the public awareness in the field. In this study, a deluged bundle was used to experimentally determine the cooling performance characteristic as well as water consumption for performance management. The above is then considered on a bigger scale to in order to open floor for further discussion on future strategies in term of the South African policy on water usage.