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  • 401.
    Jourdier, Bénédicte
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Study and implementation of mesoscale weather forecasting models in the wind industry2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As the wind industry is developing, it is asking for more reliable short-term wind forecasts to better manage the wind farms’ operations and electricity production. Developing new wind farms also requires correct assessments of the long-term wind potentials to decide whether to install a wind farm at a specific location. This thesis is studying a new generation of numerical weather forecasting models, named mesoscale models, to see how they could answer those needs. It is held at the company Maïa Eolis which operates several wind farms in France. A mesoscale model, the Weather Research and Forecasting model (WRF), was chosen and used to generate high resolution forecasts based on lower resolution forecasts from NCEP’s Global Forecasting System.

    The stages for implementation of daily forecasts for the company’s wind farms were: explore and configure the model, automate the runs, develop post-processing tools and forecasts visualization software which was intended to be used by the management team. WRF was also used to downscale wind archives of NCEP’s Final Analysis and determine the possibility to use these in assessing wind potentials. Finally the precision of the model in both cases and for each wind farm was assessed by comparing attained data from the model with real power production.

  • 402.
    Juliusson, Magnus
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    HYDRODYNAMIC OPTIMIZATION OF TWO-DIMENSIONAL MULTI-ELEMENT TRAWL-DOOR SHAPES USING LOCAL SURROGATE MODELS AND ANALYSIS OF CONTROLLABLE TRAWL-DOOR SHAPES2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The study is motivated by the quest to lower the fuel consumption of trawlers and reduce green house gas emissions. Conventional trawl-doors contribute to about one third of the trawlers fuel consumption. Design and optimization of trawl-doors using computational models is vital in minimizing the fuel consumption.The main objective of this work is to develope an optimization algorithm for the shape design of trawl-doors using computational uid dynamic (CFD) models. High-fidelity CFD models are computationally expensive and therefore, conventional optimization methods, which often require large number of evaluations are not feasible. The proposed method is iterative and uses local second order response surface approximation models of the high-fidelity CFD model, constructed in each iteration. The RSA are constructed locally and are regenerated at each iteration in new domain. We use a trust region mechanism to move the center of the search domain and to increase or decrease the size ofthe search domain. This reduces the number of evaluations. We propose novel shaped trawl-door shapes and investigate their performance. These shapes are similar to multi-element airfoils on aircraft i.e., airfoil shapes with slats and flaps. We apply the proposed optimization algorithm to the novel-shaped design of two-dimensional multi-element trawl-door shapes with several design variables controlling the slat and flap positions and alignment. The objective is to increase the hydrodynamic efficiency for a given lift constraint. The results are then compared to the performance of a typical trawl-door shape. The results indicate that a satisfactory design can be obtained at the cost of few iterations of the algorithm. We also investigate controllable trawl-doors where the flap angle can be varied, depending on the operational condition.

  • 403.
    Kabalina, Natalia
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. IDMEC, Department of Mechanical Engineering, Instituto Superior Tecnico, Universidade de Lisboa, Lisboa, Portugal.
    Polygeneration District Heating and Cooling Systems Based on Renewable Resources2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Traditional district heating (DH) and district heating and cooling (DHC) systems have to address two principal challenges: phase-out of fossil fuels in favor of renewables; and profit instability related to declines in heating and cooling demands along with electricity price fluctuations. These obstacles can be overcome at once through upgrading these systems to a polygeneration concept by means of a retrofitted air-steam gasifier and gas upgrading equipment, enabling the use of renewable feedstocks such as refuse derived fuel (RDF) and municipal solid waste (MSW). In particular, the polygeneration DHC system will be able to produce simultaneously heating, cooling, electricity and value-added products – char, syngas, synthetic natural gas (SNG) and hydrogen. This work investigates the retrofit of these DHC systems through a case study based on the existing Climaespaco facility, located in Lisboa, Portugal. Thermodynamic, exergy, economic, exergo-economic and environmental models were built in Engineering Equation Software (EES) and Matlab. Overall, both RDF and MSW were found to be technically feasible and economically viable for using as feedstocks in the polygeneration DHC system. SNG production integrated in the polygeneration DHC system through the air-steam gasification and gas upgrading equipment is judged to be practical and also boosts revenues. The highest energy efficiency is achieved for cases where char is the sole by-product. System efficiencies drop as other value-added products are included as system outputs, although the extent of the efficiency decline can be adjusted by regulating syngas and SNG production. The highest discounted net cash flows are found for the scenario where SNG, syngas and char are produced simultaneously. A payback period of 3 years was determined for this and the other cases. From the exergy and exergo-economic perspectives, the scenario of simultaneous char and syngas production is the most promising as the overall exergy efficiency has the highest value and product exergo-economic costs are the lowest. However, from the products diversity viewpoint, the simultaneous production of char, SNG, syngas and H2 is advantageous.

  • 404.
    Kabalina, Natalia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
    Costa, Mario
    IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development of a polygeneration district heating and cooling system based on gasification of RDF2014In: Proceedings of the 14th International Symposium on District Heating and Cooling,September 7th to September 9th, 2014, Stockholm, Sweden, Stockholm, 2014Conference paper (Refereed)
  • 405.
    Kabalina, Natalia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Universidade de Lisboa, Portugal.
    Costa, Mario
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Energy and economic assessment of a polygeneration district heating and cooling system based on gasification of refuse derived fuels2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 137, p. 696-705Article in journal (Refereed)
    Abstract [en]

    Conventional district heating and cooling (DHC) systems are compelled to reduce their fossil fuel dependency while ensuring profitability as cooling and heating demands decline. One solution is to retrofit the system with a gasifier and product gas upgrading equipment so that the system will be able to diversify its fuel input, including biomass and waste resources, while simultaneously producing synthetic natural gas (SNG), synthetic gas (syngas) and char complementarily to heat, cold and electricity. The main objective of this study is to assess energetically and economically a polygeneration DHC system based on gasification of refuse derived fuels considering the following sub-product scenarios: char; char and syngas; char and SNG; and char, syngas and SNG. The results show that when char is the only sub product of the modified DHC system, the investment payback is 3 years, the discounted net cash flow (DNCF) is 142 mln USD, and the system trigeneration efficiency is 83.6%. When other sub-products are supplied by the system, its performance reduces but the system DNCF increases, while the investment payback remains constant.

  • 406.
    Kabalina, Natalia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Instituto Superior Tecnico, Universidade de Lisboa, Lisboa, Portugal.
    Costa, Mario
    Instituto Superior Tecnico, Universidade de Lisboa, Lisboa, Portugal.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Impact of a reduction in heating, cooling and electricity loads on the performance of a polygeneration district heating and cooling system based on waste gasification2018In: Energy Journal, ISSN 0195-6574, E-ISSN 1944-9089, Vol. 151, p. 594-604Article in journal (Refereed)
  • 407.
    Kahandagamage, Gayan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Analysis of the effect of charge air temperature and humidity on the combustion process of diesel engines at Heladhanavi Power Plant, Puttalam, Sri Lanka2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days.

    This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity.

    The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion.

    A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion.

    It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time.

    Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value.

  • 408.
    Kalioras, Konstantinos
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Repowering of small scale Wind PowerPark in the region of Kastri – Evia Island,Greece2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In July 2001 in the region of Kastri Platanistou in Evia, Greece a wind power park of 5 MWinstalled capacity, began its commercial power production under the supervision of the companyMELTEMI-KASTRI.During these 6 years of its operation significantly reduced incomes were recorded compared to theinitial study financial analysis. Apparently loss of income occurred due to technical failures;nevertheless more costly might have been a suboptimal primary energy analysis.Herein, the collected data from the nacelle of the wind turbines and a net installed in the site wereanalyzed in order to estimate the site’s wind energy potential and gain knowledge of the parametersthat so far affected the overall production. The analysis was performed through Windrose andWAsP software.Aiming to maximize the exploitation of the site’s wind energy potential, several wind turbinemodels in different installation points were examined. Further analysis of the exported resultsindicated the optimum scenario, finally suggested to the owners of the wind farm.

  • 409.
    Kamranmehr, Hojat
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Design, Simulation, Performance Analysis, and Economic Evaluation of Portable Off-Grid Photovoltaic-Powered Water Pumping System for Remote Locations2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Everybody knows that water is necessary for life. Access to groundwater and energy for people living in remote areas always has been challenging. Many people living in remote areas deprived of electrical distribution lines and they have to use nonelectrical or conventional water pumping systems, which have several problems. Water pumping systems powered by solar energy is suitable choice technically, economically and environmentally in villages, farms, and ranches located remotely; especially for areas with great potential of solar energy like African countries.

    In this thesis, an innovative design of portable off-grid photovoltaic-powered water pumping system is presented. The purpose of this research is to design different off-grid PV water pumping system, which will be portable, more practical and high efficient comparing to other available systems. This project also aims to obtain an optimum sizing of the PV arrays, practical installation of the system, selecting appropriate site, estimation the availability of sun radiation, evaluate the performance of the system, and SWOT analysis of the system. Simulation software, PVSYST are used to analyze and optimize the system. Metrological data of Bloemfontein in South Africa is selected as a case study.

    In the beginning, reviews of available literature on different water pumping systems are carried out. Several conventional water-pumping systems, configurations and different components of solar-PV water pumping system are studied. After designing a portable off-grid photovoltaic-powered water pumping system, simulation is carried out. Other possibilities for system configuration and several different system layouts and coupling strategies are considered.  Power conditioning unit in the proposed strategy is MPPT DC converter with minimum and maximum voltage of 19 and 38 respectively. Two deep well pumps of 140 W and two PV modules with nominal power of 340 Wp (STC), are configured in the system for delivering water need of 7 m³/day, with maximum pumping depth of 40 m, storage tank with 28 m³ volume, and piping length of 84m.

    In the end, simulation results show that the designed system is able to pump 2487m³ water per year and approximately fulfil water needs with high efficiency, taking into account sun radiation, PV array and pump power.  Pump efficiency and system efficiency are reached 51% and 85.2 % respectively, which are substantial results for this system.

    Moreover, it interestingly noticeable that unused energy is 0.1 kWh/kWp/day and it shows that this system operates properly. Performance ratio accounts for 70.2% during system simulation, which will be substantially great indicator of the quality of the system itself, independently of the incoming irradiance. Economic evaluation also shows significant results for the proposed system. Total yearly cost is estimated € 947 per year. Cost of pumped water is evaluated 0.38 € per m³, which makes the designed system cost effective.

    Simulation results, performance analyzing, losses determination and economic evaluation indicate that the designed system is a sustainable, cost-effective, and reliable solution for pumping water in remote locations.  

  • 410.
    Kapambwe, Elias
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Economic Feasibility Photovoltaic/Diesel/Battery Hybrid Power Syatems to replace stand-alone diesel generators in off-grid remote areas of Zambia2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 411.
    Kapasa, Christopher
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Evaluation of Current and Feasible Future Use of Geothermal Energy at Chinyunyu Hot Spring, Zambia2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main source of geothermal energy is the heat flow from the mantle beneath the Earth’s surface, generated by the gradual decay of radioactive isotopes in the Earth‘s crust. A hot spring is produced by the emergence of geothermally heated groundwater flowing out to the Earth’s surface.

    The Chinyunyu hot spring is located about 90km east of Lusaka, Zambia. Water from the spring has been artificially channeled into a large excavated pool which is used as a bathing place. Since the undiluted spring water at the source is too hot for comfortable bathing, it is mixed with surface water to reduce the temperature.

    There is potential for electricity generation from the Chinyunyu hot spring. Even the most recent proposed survey by the Japanese International Corporation Agency (JICA) in conjunction with the Geological Survey Department in the Ministry of Mines, Energy and Water Development (MMEWD), could not progress beyond the planning stage due to lack of funds. Notable among interest groups in geothermal energy was Kalahari GeoEnergy Limited, a private company registered in Zambia. Even though the objective of Kalahari GeoEnergy Limited was to explore and, if viable, develop geothermal energy resources to produce electrical power in Eastern and Southern Africa, the company concluded that the Chinyunyu Hot Spring was not viable for electricity generation without drilling any test wells and reaching for higher temperatures.

    The overall purpose of this study is to evaluate the benefits of the current use of the geothermal energy from the Chinyunyu Hot Spring, and also to explore some technically and economically feasible future applications. The study recommends electrical power generation by a binary cycle, with the assumption that drilling for larger mass flow and higher temperatures can be done. Results show that a net power capacity of 233 kWe is technically feasible with minimum environmental impact. However, the expected capital cost in the order of USD 3.4 million and specific cost of $14,500/kWe can hardly be justified without support mechanisms.

  • 412.
    KAVUMA, CHRISH
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Variation of Methane and Carbon dioxide Yield in a biogas plant2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 413. Kazachkov, I.V
    et al.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Popa, Marianne Salomon
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development of the mobile computer and special notebook tools and technologies for the electronic educational international network2009Report (Other academic)
  • 414. Kazachkov, I.V
    et al.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Salomon Popa, Marianne
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Virtual university environment: swedish-ukrainian network for design of internet-based education software2011Report (Other academic)
  • 415. Kazachkov, I.V
    et al.
    Geraimchuk, M.D
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Development and implementation of multimedia educational systems for universities and secondary schools2007Conference paper (Other academic)
  • 416.
    Kazachkov, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A combined space discrete algorithm with a taylor series by time for solution of the non-stationary CFD problems2011In: WSEAS Transactions on Fluid Mechanics, ISSN 1790-5087, Vol. 6, no 1, p. 51-69Article in journal (Refereed)
    Abstract [en]

    The first order by time partial differential equation (PDE) is used as models in applications such as fluid flow, heat transfer, solid deformation, electromagnetic waves, and many others. In this paper we propose the new numerical method to solve a class of the initial-boundary value problems for the PDE using any known space discrete numerical schemes and a Taylor series expansion by time. Derivatives by time are got from the outgoing PDE and its further differentiation (for second and higher order derivatives by time). By numerical solution of the PDE and PDE arrays normally a second order discretization by space is applied while a first order by time is sometimes satisfactory too. Nevertheless, in a number of different problems, discretization both by temporal and by spatial variables is needed of highest orders, which complicates the numerical solution, in some cases dramatically. Therefore it is difficult to apply the same numerical methods for the solution of some PDE arrays if their parameters are varying in a wide range so that in some of them different numerical schemes by time fit the best for precise numerical solution. The Taylor series based solution strategy for the non-stationary PDE in CFD simulations has been proposed here that attempts to optimise the computation time and fidelity of the numerical solution. The proposed strategy allows solving the non-stationary PDE with any order of accuracy by time in the frame of one algorithm on a single processor, as well as on a parallel cluster system. A number of examples considered in this paper have shown applicability of the method and its efficiency.

  • 417.
    Kazachkov, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Blow-up regimes by non-isothermal gas/steam filtration through the underground particle layer with internal heat sources2009In: International journal of geology, ISSN 1998-4499, Vol. 3, no 4, p. 101-111Article in journal (Refereed)
    Abstract [en]

    Two-dimensional non-stationary model for the non-isothermal gas/steam filtration through a monospherical particle layer with internal heat generation is considered with a particular emphasis on the non­thermal gas/particles local equilibrium, taking into account the real non-linear properties of the media. The boundary problem for the multiphase system of gas and particles is formulated and solved numerically using the effective finite-difference fractional time-step method. It is shown that some initial thermodynamic perturbations in the system may cause localization of a gas heating (mainly due to a non-linear heat conductivity), which will lead to a temperature escalation in a specific spatial subdomains. Furthermore, the effects of other parameters such as particles’ size and porosity of the layer, an amplitude and a form of an initial temperature perturbation, the level of an initial temperature difference between the gas and solid phases, etc. are analyzed. The model considered can be comparably easily modified for the three-dimensional non-stationary case using the numerical algorithm applied. An examples of computer simulations are presented for the cases of the volcanic geological mains and for the nuclear power safety. The phenomenon of the blow-up regimes due to non-linear heat conductivity causing local abnormal heat escalation in a narrow domain may be of great interest for some natural, as well as technical systems and processes.   

  • 418.
    Kazachkov, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Heat transfer and dynamics of the droplet on a superheated surface2012In: WSEAS Transactions on Heat and Mass Transfer, ISSN 1790-5044, Vol. 7, no 2, p. 47-57Article in journal (Refereed)
    Abstract [en]

    The conditions governing the collapse of a "Leidenfrost drop", e.g. a liquid drop supported by a vapour film on a heated surface was studied analytically. Robust analytical model for the phenomenon has been developed and numerical simulation has been done. The model was represented by two second-order non-linear differential equations for the radius of evaporating drop and its distance over the heated surface. The results obtained have shown the high-frequent oscillations of the drop over the hot plate until complete evaporation of the drop occurs. In contrast with existing precise complex models, the mathematical model developed was simple and could be used for the qualitative estimation of different parameters and quantitative estimation of the integral behaviours of the drop such as time for complete drop evaporation. The effects of surfactants on the Leidenfrost phenomenon and its industrial applications were discussed.

  • 419.
    Kazachkov, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Parametric Excitation and Suppression of Oscillations at the Interfaces of Continua for the Processes Control: Jet and Film Flows, Granular Media, Flow in a Channel with Phase Change2011In: WSEAS Тransactions on fluid mechanics, ISSN 1790-5087, no 3, p. 1-26Article in journal (Refereed)
    Abstract [en]

    The problem is important for the practical applications in three aspects: 1. Excitation of parameter oscillations in continua in touch with necessity of intensification of various technological and technical processes: heat and mass transfer, mixing, decreasing of viscosity, improving of quality for crystallizating metal and many other phenomena. 2. Excitation of parameter oscillations in touch with nesessity of disintegration of jet and film flows: air spray, spray-coating, metal spraying, dispergation and granulation of materials (e.g. particles’ producing from molten metals), etc. 3. Suppression of parameter oscillations for stabilization of unstable regimes and processes: jet-drop and film screens for protection of diaphragm of experimental thermonuclear reactor, thermal instability and control of fusion reactor, control of electromechanical and electrochemical instabilities, combustion stability, decreasing of hydrodynamic and acoustic resistance, etc. In some cases, parametric control makes possible for not only intensification of processes but also for operation of the processes that are impossible without parametric control.It was considered a lot of different as linear as well as nonlinear model situations. As a result there were obtained some interesting regularities of parametric wave excitation and suppression in film flows including three new phenomena of parametric film decay: resonance decay, soliton-like decay and shock-wave decay. The phenomena were first theoretically predicted and then experimentally invented and investigated. Based on these new phenomena we developed, created and tested the prospective dispergators and granulators for some metals and other materials.  

  • 420.
    Kazachkov, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    The mathematical models for penetration of a liquid jets into a pool2011In: WSEAS Тransactions on fluid mechanics, ISSN 1790-5087, p. 1-22Article in journal (Refereed)
    Abstract [en]

    The peculiarities of a jet penetrating the liquid pool of different density were examined by means of the non-linear and linear mathematical models derived including bending instability. Based on experimental observations reported in the literature for a number of situations, the penetration behaviour was assumed to govern the buoyancy-dominated regime. A new analytical solution of the one-dimensional non-linear model was obtained for the jet penetration in this condition, as function of Froude number, jet/ambient fluid density ratio and other parameters. The solution was analysed for a number of limit cases. Analytical solution of the non-linear second-order equation obtained can be of interest for other researchers as the mathematical result.

  • 421.
    Kazachkov, Ivan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Konoval, O. V.
    Non-linear mathematical models for the jets penetrating liquid pool of different density under diverse physical conditions and their simulation2013In: WSEAS Transactions on Applied and Theoretical Mechanics, ISSN 1991-8747, E-ISSN 2224-3429, Vol. 8, no 2, p. 156-169Article in journal (Refereed)
    Abstract [en]

    The problem of modelling and simulation for the jets penetrating pool of other liquids is considered under different physical conditions and situations. It may happen for example in severe accidents at the nuclear power plants in touch with development and operation of the passive protection systems against severe accidents, as well as in many other problems. The specific peculiarities of the penetrating jets are discussed and mathematical modelling of the problem is considered. The non-linear second-order differential equation and the Cauchy problem is analyzed and solved analytically using the simultaneous transformation for both dependent and independent variables. The result obtained may be useful for theoretical and practical applications, where the liquid jet or solid rod is penetrating the pool of other liquid.

  • 422.
    Kazachkov, Ivan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Moghaddam, V. H.
    Specific peculiarities of the jets penetrating the liquid pool of different density under severe accidents at the NPP conditions and their modeling and simulation2012In: WSEAS Transactions on Applied and Theoretical Mechanics, ISSN 1991-8747, E-ISSN 2224-3429, Vol. 7, no 4, p. 276-287Article in journal (Refereed)
    Abstract [en]

    The paper is devoted to one of the problems of the modelling and simulation of the severe accidents at the nuclear power plants (NPP) in touch with development and operation of the passive protection systems against severe accidents. The results of the mathematical modelling and simulation of the jets penetrating the pool of other liquid under diverse conditions as well as an analysis of the experimental data have clearly shown that the falling buoyant jets penetrating the pool of other liquid differ a lot from the classical jets moved by pressure gradient. For example, the classic scheme with monotone jet radius evolution does not work in this case. There is clearly observed phenomenon that jet is going with nearly constant radius up to some point in a pool, then at the point of "bifurcation" it substantially changes its radius abruptly (jet switches its one constant radius to the another one). These specific peculiarities of the penetrating jets are discussed and mathematical modelling of the problem is considered.

  • 423.
    Kazachkov, Ivan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Analysis of Annular Two-phase Flow Dynamics under Heat Transfer Conditions2005In: Journal of Enhanced Heat Transfer, ISSN 1065-5131, E-ISSN 1563-5074, Vol. 1, p. 1-22Article in journal (Refereed)
    Abstract [en]

    An analytical investigation was performed for the instability phenomenon of two-phase annular flow with a thin film flow on the channel wall under the heat transfer conditions. The analyses of heat transfer behaviours of two-phase annular flow showed that the overall heat transfer behaviours between the fluids and the channel wall were dominated by the thickness of a thin liquid film. The mass, momentum and energy equations for two phases were employed to study the perturbation behaviours in both fluids. Two different boundary conditions at the wall were considered: heat transfer with constant temperature along the wall and then conditions of constant heat transfer along the wall. Basic equations were solved on both hydrodynamic and thermal perturbations in two fluids for two different boundary conditions. Scrupulous analysis was done for the axially symmetrical wave at two-phase interface. The results showed that in case of small flow rate, the hydrodynamic perturbations in both fluids always decreased. Only kinematical waves at the gas-liquid interface could exist, but did not grow. The waves moved at the same velocity as the gas phase in the channel core. However, the thermal perturbations might grow in some conditions. They finally caused hydrodynamic perturbations, which might also grow, causing a flow instability. The solutions for characteristics of the interface waves such as wavelength and increment of perturbations were obtained. More interestingly, for the isothermal boundary conditions it was found that the maximum increment of perturbations (most unstable) was only dependent on the thermodynamical property ratios of the gas and liquid.

  • 424.
    Kazachkov, Ivan V.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Parametric excitation and suppression of oscillations at the interfaces of continua for the processes’ control in jet and film flows, channel flows with phase change and in granular media2015In: WSEAS Transactions on Applied and Theoretical Mechanics, ISSN 1991-8747, E-ISSN 2224-3429, Vol. 10, p. 1-23Article in journal (Refereed)
    Abstract [en]

    The problem is interesting theoretically and important for the practical applications in three aspects: 1. Excitation of parameters’ oscillations in continua in touch with intensification of various technological and technical processes: heat and mass transfer, mixing, decreasing the viscosity, improving the quality for crystallizing metal and many other phenomena. 2. Excitation of parameters’ oscillations in touch with necessity of disintegration of jet and film flows: air spray, spray-coating, metal spraying, dispersing and granulation of materials (e.g. particles’ producing from molten metals), etc. 3. Suppression of oscillations for stabilization of unstable regimes and processes: jet-drop and film screens for protection of diaphragm of experimental thermonuclear reactor, thermal instability and fusion control in reactor, control of electromechanical and electrochemical instabilities, combustion stability, decreasing the hydrodynamic and acoustic resistance, etc. In some cases, parametric control makes possible not just intensification the processes but also running such processes, which are impossible without parametric control. A lot of different linear as well as nonlinear model situations have been considered. As a result some interesting peculiarities of parametric wave excitation and suppression in film flows including three new phenomena of parametric film decay were revealed: resonant decay, soliton-like decay and shock-wave decay. The phenomena were first theoretically predicted and then experimentally invented and investigated. Based on these new phenomena we developed, created and tested the prospective dispersion and granulation machines for some metals and other materials.

  • 425.
    Kessar, Alexandros
    et al.
    KTH.
    Jöcker, Markus
    KTH.
    Fransson, Torsten
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Rehder, Hans Jürgen
    Kost, Friedrich H.
    Flow Measurements for Low Engine order Excitations in a High Pressure Turbine stage2005Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates and evaluates unique flow measurement results obtained in a high pressure test turbine, in order to analyze the effect of Low Engine Order (LEO) excitations. A stator was modified to induce LEO flow variations by either imposing a throat width variation or a blockage of the trailing edge cooling flow from some of the vanes. Laser Two Focus (L2F) and pressure probe measurements were performed at subsonic and transonic flow conditions, without and with the rotor installed and operated. Time resolved velocity data was obtained in front and inside of rotor passages covering the Low Engine Order variation period. The presented results evaluation focuses only on L2F measurements and show that the LEO variation of flow velocity and turbulence intensity is most visible in the gap between stator and rotor and at the first measurement location inside the rotor passage. The overall trend is that stator exit flow Mach numbers are higher behind the passages with smaller pitch and vice versa.

  • 426.
    Khan, Ershad
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mainali, Brijesh
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Techno-Economic Analysis of Small Scale Biogas Based Poly generation Systems in Bangladesh2012Conference paper (Other academic)
    Abstract [en]

    Access to electricity, clean drinking water andclean cooking gas services are genuine needs of the rural poor in order to improvetheir living conditions. One can think of addressing these needs individually orinstead use an integrated approach. Looking for solutions using a holisticapproach should always have a better impact. A small scale and distributedbiogas based poly generation system could be an effective solution to bringsustainable development to remote and rural areas of Bangladesh. Biogasdigesters are a popular and promising rural energy technology and the integrationof biogas production with power generation and water purification is aninnovative approach. This paper discusses such an integrated poly generationsystem and analyzes the techno-economic performance of the scheme for meetingthe demand of electricity, cooking energy and safe drinking water of 30households in a rural village of Bangladesh. The mass flows and energy balance,life cycle cost (levelized cost) of producing electricity, cooking gas and safedrinking water as well as the payback period of such a poly generation system wereestimated. In this study, it has been found that this poly generation system ismuch more competitive and promising than other available technologies whenattempting to solve the energy and arsenic-related problems in Bangladesh. Thedeterminant factors influencing the performance of the system and their impacton the cost have been looked at under different conditions. This paper willserve as a background paper in order to expand research further in thedirection of making biogas based poly generation system as a successfulbusiness solution in rural areas.

  • 427.
    Khan, Ershad Ullah
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Mainali, Brijesh
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Techno-economic analysis of small scale biogas based polygeneration systems: Bangladesh case study2014In: Sustainable Energy Technologies and Assessments, ISSN 2213-1388, E-ISSN 2213-1396, Vol. 7, p. 68-78Article in journal (Refereed)
    Abstract [en]

    Access to electricity, clean energy, and safe drinking water services are genuine needs of the rural poor for their welfare. These needs can be addressed either individually or in an integrated approach. Biogas digesters are promising in the rural setting and integration of biogas production with power generation and water purification is an innovative concept that could be applied in remote areas of Bangladesh. This paper presents a new concept for integrated biogas based polygeneration and analyzes the techno-economic performance of the scheme for meeting the demand of electricity, cooking energy and safe drinking water of 30 households in a rural village of Bangladesh. The specific technologies chosen for the key energy conversion steps are as follows: plug-flow digester; internal combustion engine; and air-gap membrane distillation. Mass flows and energy balance, levelized cost of producing electricity, cooking gas and safe drinking water as well as the payback period of such a polygeneration system were analyzed. The results indicate that this polygeneration system is much more competitive and promising (in terms of levelized cost) than other available technologies when attempting to solve the energy and arsenic-related problems in Bangladesh. The payback period of such system is between 2.6 and 4 years.

  • 428. Khan, M. Ajmal
    et al.
    Raza, Rizwan
    Bohn Lima, Raquel
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Chaudhry, M. Asharf
    Ahmed, E.
    Khalid, N. R.
    Abbas, Ghazanfar
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Nasir, Nadeem
    Effect of titania concentration on the grain boundary conductivity of calcium-doped ceria electrolyte2014In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 40, no 7, p. 9775-9781Article in journal (Refereed)
    Abstract [en]

    A solid-state technique was used to synthesize ceria-based (CDC-xT, in which x=0-1 mol%) solid electrolyte ceramics. The effects of doping the ceramic solid electrolyte (CDC) with titanium oxide were studied with regard to densification, crystal structure, morphology, electro-impedance spectroscopy and fuel cell performance. TiO2 doping afforded materials a 95% relative density at 940 degrees C, approximately 200 degrees C lower than the temperature required without titanium oxide. The addition of titanium oxide (TiO2) reduced the CDC sintering temperature and significantly improved the grain boundary conduction. The minimum grain boundary resistivity was obtained at 0.8 mol% TiO2. X-ray diffraction (XRD) results showed that the lattice parameters enhanced with increased titanium oxide concentrations up to 0.8 mol%, revealing the solubility limit for Caria's fluorite structure. The optimum doping level (0.8 mol%) is provided maximum conductivity. Conductivities were measured using EIS (Electrochemical Impedance Spectroscopy) with a two-probe method, and the activation energies were calculated using the Arrhenius plots. The maximum power density (660 mW/cm(2)) was achieved with CDC 0.8T electrolyte at 650 degrees C using LiCuZnNi oxide electrodes.

  • 429.
    Khan, MD. Ershad Ullah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Feasibility Analysis of Biogas Based Polygeneration for Rural Development in Bangladesh2014Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Around three-quarters of Bangladeshis (total population 164 million) live in rural areas: only 25% of these households have access to grid electricity with non-reliable supply despite the country’s successful rural electrification program, kerosene is the predominant source for lighting, and woody biomass is virtually the only option available for cooking. Aside from this energy service challenges the rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. Access to electricity, clean cooking gas, and safe drinking water services are genuine needs of the rural poor and are essential to improving welfare. These needs can be addressed individually or using an integrated approach. Anaerobic digesters are now a proven technology and remain economically promising in the rural setting, where connection to the public electric and gas grids are not available/either not cost effective or feasible, and where energy and water scarcity are severe. As the technologies continue to improve, and as energy and safe water becomes scarce and fossil fuel energy prices rise, renewable energy based services and technological integration becomes more viable techno-economically. In these circumstances, the integration of biogas digester with power generation and water purification unit is an innovative concept that could be applied in remote areas of Bangladesh.

     

    This work presents a new concept for integrated polygeneration and analyzes the techno-economic performance of the scheme for meeting the demand of electricity, cooking energy and safe drinking water of 30 households in a rural village of Bangladesh. This study considers a holistic approach towards tackling both of these issues via integrated renewable energy-based polygeneration employed at the community level. The polygeneration unit under consideration provides electricity via cow dung-fed digester, which in turn is coupled to a gas engine. Excess digester gas is employed for cooking, while waste heat from the process drives a membrane distillation unit for water purification. The specific technologies chosen for the key energy conversion steps are as follows: plug-flow digester; internal combustion engine; and air-gap membrane distillation. The technical features, energy consumption, and potential of renewable energy use in driving the main integrated processes are reviewed and analyzed in this thesis. This study also examines one approach by investigating the application of suitable membrane technologies, specifically air gap membrane distillation (AGMD), as a promising method for small-scale, low cost deployment. 

     

    Experimental results show that the tested AGMD prototype is capable of achieving high separation efficiency, as all product water samples showed arsenic levels below accepted limits. Mass flows and energy balance, life cycle cost (levelized cost) of producing electricity, cooking gas and safe drinking water as well as the payback period of such a polygeneration system were studied. The results indicate that this polygeneration system is much more competitive and promising than other available technologies when attempting to solve the energy and arsenic-related problems in Bangladesh. One of the main encouraging issues of this integrated system is the levelized cost of the three major services: cooking gas (0.015 USD/kWh), electricity (0.042 USD/kWh–an orders of magnitude lower than comparable photovoltaic or wind systems) and safe drinking water (0.003 USD/liter). Additionally, the payback period is between 2.6 to 4 years.

  • 430.
    Khan, MD. Ershad Ullah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Renewables Based Polygeneration for Rural Development in Bangladesh2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Despite the country's rural electrification programme, kerosene is the predominant source for lighting, and unsustainable and polluting woody biomass is virtually the only option available for cooking. The rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. The present work has taken an integrated approach in an attempt to mitigate problems through small-scale polygeneration, a concept linking renewable energy sources to these energy needs via novel energy conversion systems.

    Anaerobic digesters (AD) for biogas production are promising in the rural setting, and field surveys have identified problems in the construction, maintenance and operation of existing AD, particularly in overall performance of household digesters. Based on these results, a number of operational and technological improvements are suggested for employing digesters in polygeneration units. This study also examines one approach for small-scale, low cost arsenic removal in groundwater through air gap membrane distillation, a thermally-driven water purification technology.

    Integration of biogas production with power generation and water purification is an innovative concept that lies at the core of feasibility analyses conducted in this work. One of the case studies presents a new concept for integrated biogas based polygeneration and analyzes the techno-economic performance of the scheme for meeting the demand of electricity, cooking energy and safe drinking water of 30 households in a rural village of Bangladesh. The specific technologies chosen for the key energy conversion steps are as follows: plug-flow digester; internal combustion engine; and membrane distillation. One major concern is local feedstock availability for the digester, since a single feedstock is impractical to serve both cooking, lighting and water purification systems. In this circumstance solar PV could be a potential option for integrated hybrid systems.

  • 431.
    Khan, MD. Ershad Ullah
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Water purification of arsenic contaminated drinking water via air gap membrane distillation (AGMD)2014In: Periodica Polytechnica, Mechanical Engineering, ISSN 1587-379X, Vol. 58, no 1, p. 47-53Article in journal (Refereed)
    Abstract [en]

    Arsenic contamination in shallow tubewell water is a serioushealth issue in Bangladesh and other Southeast Asian countries.Rural and remote areas in these locations continue toface tremendous challenges in providing access to affordableand safe arsenic-free drinking water. In recent years, intensiveefforts have been undertaken to identify appropriate technologiesfor arsenic removal. This study examines one approach byinvestigating the application of suitable membrane technologies,specifically air gap membrane distillation (AGMD), asa promising method for small-scale, low cost deployment. Theobjective of this study was to test an AGMD commercial prototype(nominal capacity of 2 L/hr) with three different feedstocks:arsenic-containing groundwater (medium concentration) andarsenic-spiked tap water (medium and high concentrations).Results show that the tested AGMD prototype is capable ofachieving excellent separation efficiency, as all product watersamples showed arsenic levels well below WHO accepted limits(10 μg/L) even for initial concentrations over 1800 μg/L.Parametric studies with focus on variation of coolant temperatureillustrate the possibility of integrating AGMD in variousthermal systems.

  • 432.
    Khan, MD. Ershad Ullah
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Hybrid Renewable Energy with Membrane Distillation Polygeneration for Rural Households in Bangladesh: Pani Para Village Case Study2014In: 2014 INTERNATIONAL CONFERENCE ON RENEWABLE ENERGY RESEARCH AND APPLICATION (ICRERA), IEEE , 2014, p. 359-362Conference paper (Refereed)
    Abstract [en]

    Despite the country's rural electrification program, kerosene is the predominant source for lighting, and woody biomass is virtually the only the option available for cooking. Aside from this energy service challenges the rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. Access to electricity, clean cooking gas, and safe drinking water services are genuine needs of the rural poor and are essential to improving welfare. These needs can be addressed individually or using an integrated approach. This study considers a holistic approach towards tackling both of these issues via integrated renewable energy-based polygeneration employed at the community level. The polygeneration unit under consideration provides electricity via a pV array and cow dung-fed digester, which in turn is coupled to a gas engine. Excess digester gas is employed for cooking and lighting, while waste heat from the process drives a membrane distillation unit for water purification. The system is sized to serve a community of 52 households (Pani Para, Faridpur District) with 14 kWe peak demand and 250 kWh/day primary electricity loads. Technical assessments and optimization have been conducted with HOMER. Results show that electricity demand can be met with such a system while simultaneously providing 0.4 m(3) cooking fuel and 2-3 L pure drinking water per person per day. Cost estimates indicate that this approach is highly favorable to other renewable options.

  • 433.
    Khan, MD. Ershad Ullah
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Optimization of hybrid renewable energy polygeneration system with membrane distillation for rural households in Bangladesh2015In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 93, p. 1116-1126Article in journal (Refereed)
    Abstract [en]

    Despite the country's rural electrification program, kerosene is the predominant source for lighting, and woody biomass is virtually the only option available for cooking. The rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. Biogas plants and pV are individually impractical to serve both cooking, lighting and water purification systems, and their combined applications are extremely limited. This study considers a holistic approach towards tackling both of these issues via integrated renewable energy-based polygeneration employed at the village level. The polygeneration unit under consideration provides electricity via a pV array and animal and agriculture waste-fed digester, which in turn is coupled to a gas engine. Excess digester gas is employed for cooking and lighting, while waste heat from the process drives a membrane distillation unit for water purification. Technical assessments and optimization have been conducted with HOMER (Hybrid Optimization of Multiple Energy Resources). Results show that daily electricity demand can be met with such a system while simultaneously providing 0.4 m3 cooking fuel and 2e3 L pure drinking water. Cost estimates indicate that this approach is highly favorable to other renewable options. The pay back period of such system is between 3 and 4 years.

  • 434.
    Khan, MD. Ershad Ullah
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Review of biogas digester technology in rural Bangladesh2016In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 62, p. 247-259Article in journal (Refereed)
    Abstract [en]

    Bangladesh has been facing severe energy crises (lack of electricity and gas supply network) during the last three decades, especially in rural areas. These areas are characterized by their often inefficient use of woody biomass, mainly for cooking purposes. To avoid the resulting environmental degradation and achieve sustainable development, access to clean and affordable energy is essential. Upgrading existing biomass resources (i.e., animal manure, crop residues, kitchen waste and green wastes) to biogas shows significant promise in this respect. This article presents a review of the current status of biogas digester technology in Bangladesh with focus on households in rural areas, covering 75% of the total population. Currently there exists a substantial gap between technical and cost-effective potential and the achievable potential due to lack of technical knowledge, high installation and operation costs, feedstock availability and limited end user applications. As a result only one percent of the overall biogas potential, estimated at 14.5x106 m3/yr, has been achieved despite government programs for promoting digester installation. Via in-field surveys this review has identified problems in the construction, maintenance and operation of biogas digesters, particularly in overall performance of household digesters. Based on these results a number of operational and technology improvements are suggested. Three digester implementation scenarios are introduced, and performance and cost estimates are projected to 2040. The most ambitious scenario leads to a five-fold increase in biogas output as compared to today’s levels; levelized energy costs can be halved with proper choice of digester technology.

  • 435.
    Khorsand, Khashayar
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Numerical heat transfer studies and test rig preparation on a gas turbine nozzle guide vane2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Heat transfer study on gas turbine blades is very important due to the resultant increase in cycle thermal efficiency. This study is focused on the heat transfer effects on a reference nozzle guide vane and test rig component preparation in heat and power technology division at KTH. In order to prepare the current test rig for heat transfer experiments, some feature should be changed in the current layout to give a nearly instant temperature rise for heat transfer measurement. The heater mesh component is the main component to be added to the current test rig. Some preliminary design parameters were set and the necessary power for the heater mesh to achieve required step temperature rise was calculated. For the next step, it is needed to estimate the heat transfer coefficient and the other parameters for study on the reference blade using numerical methods. Boundary layer analysis is very important in heat transfer modeling so to model the reference blade heat transfer and boundary layer properties, a 2D boundary layer code TEXSTAN is used and the velocity distribution around the vane was set to an input dataset file. After elements refinement to ensure the numerical accuracy of TEXSTAN code, various turbulence modeling was check to predict the heat transfer coefficient and boundary layer assessments. It was concluded from TEXTAN calculations that both suction and pressure side have transition flow while for the suction side it was predicted that the flow regime at trailing edge is fully turbulent. Based on the Abu-Ghannam –Shaw Transition model and by the aid of shape factor data, momentum Reynolds number and various boundary layer properties, it was concluded that the pressure side remains in transient region.

  • 436.
    Khudur, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aluminium alloys ability to catalyse the oxidation of biodiesel: Development of a procedure to test alloys2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys.

  • 437.
    Khudur, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aluminium alloys ability to catalyse the oxidation of biodiesel: Development of a procedure to test alloys2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys.

  • 438.
    Kieffer, Benoit
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Potential market for small-scale gasifiers in rural areas of developing countries2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis report assesses the potential market for small-scale gasifiers in rural areas of developing countries and regions. Biomass is already widely used in these areas for energetic purpose, giving gasification an interesting niche market for remote electricity production. Success factors include a high reliability, an efficient biomass supply chain and sufficient local electricity needs. Suitable fuel for a gasifier must be available at low cost, which could be wood harvested locally or agricultural residues such as rice husks or nut shells.

    A good potential for gasifiers fueled by wood has been identified in Eastern Africa, based on FAO's wood supply-demand models. South-East Asia and South America produce a lot of agricultural residues suitable for gasification. However, the electrification rate in South America is already high, which reduces considerably the interest for small-scale decentralized electricity production.

    Taking into account all these parameters, the most promising countries are Nigeria, India, Myanmar and Indonesia. Thailand, Cambodia and the Philippines also offer opportunities in the rice and sugar industries, while the wood industry in Cameroon shall deserve a deeper investigation.

  • 439.
    Kithsiri, U. G.
    et al.
    KTH. The Open University of Sri Lanka, Colombo, Sri Lanka.
    Peiris, A. P. T. S.
    KTH. The Open University of Sri Lanka, Colombo, Sri Lanka.
    Wickramarathna, Tharanga
    KTH. The Open University of Sri Lanka, Colombo, Sri Lanka.
    Amarawardhana, Kumudu
    KTH. The Open University of Sri Lanka, Colombo, Sri Lanka.
    Abeyweera, Ruchira
    KTH. The Open University of Sri Lanka, Colombo, Sri Lanka.
    Senanayake, N. N.
    Jayasuriya, Jeevan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. EIT InnoEnergy, Stockholm, Sweden.
    Fransson, Torsten H.
    EIT InnoEnergy, Eindhoven, Netherlands.
    A Remote Mode Master Degree Program in Sustainable Energy Engineering: Student Perception and Future Direction2018In: 20th International Conference on Interactive Collaborative Learning, ICL 2017, Springer Verlag , 2018, p. 673-683Conference paper (Refereed)
    Abstract [en]

    Remote mode higher education at postgraduate level is becoming popular among students because of flexible learning opportunity and the accessibility to study programs offered by renowned universities in the world. Fast development of internet facilities and learner management systems along with the development of remote educational pedagogy have been the driving force behind the acceptance and development of distant mode study programs. The success of such a study programs is largely affected by several factors that are unique to the university that offers the study program and the demography of participants as well as infrastructure and the student support available at the receiving end. In the present study, the successes and the drawbacks as perceived by the participants of a distant master study program are evaluated. The study program considered was the Sustainable Energy Engineering Worldwide (SEEW) master degree program which was offered by the Royal Institute of Technology (KTH) in Sweden to students in Sri Lanka (Apart from Sri Lanka, SEEW was offered by KTH to some other countries; Zimbabwe, Ethiopia, Mauritius). The objective of offering the SEEW master program was to assist the developing nations to build up human resources with expertise in sustainable energy generation and utilization, hence contributing to national development. As such the program also generally contributes to global efforts of alleviating unfavourable environmental impacts connected with power generation and utilization. The SEEW master program consisted of 120 ECTS (ECTS: European Credit Transfer System) and the courses were offered over three semesters followed by a research project of 30 ECTS during the fourth semester. Lectures were delivered synchronous with the parallel KTH on-campus study program in real time through internet with the support of a learner management system. The students were attached to the Open University of Sri Lanka (OUSL) for providing academic support where necessary and for the supervision of written and online examinations. The first enrolment consisted of 21 students in intake 2008 and the program was conducted with varying student numbers until the intake 2010. A total of 72 students have successfully completed the SEEW program and they are at presently employed in key organizations in the energy sector as well as in national universities in Sri Lanka. The paper focusses on eight key areas that the students have identified as vital for success for this type of programs. These key areas are the effectiveness of web tools used, standard of teaching, standard of course content, examination procedures, online assessment, thesis projects, benefit to the students, and benefits to facilitating university. In the study 36 students responded to survey and overall rating of the program successfulness was identified as 72%. 

  • 440.
    Kithsiri, Udalamattha Gamage
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Performance Improvement of a Diesel Engine Power Plant with Optimal Utilization of Waste Heat2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to temperature and humidity deviations from the standard ISO conditions in real operational conditions in the tropical countries the performance of diesel engines used for power generation drops significantly. One of the reasons for dropping the engine performance is due to engine de-rating, hence increasing the specific fuel consumption. The present study was undertaken to develop a model for predicting whether the prevailing site conditions cause de-rating at a specific power plant in Sri Lanka.  

    The model was developed with the aid of recorded information in previous studies and was validated with site conditions revenant to a selected location in Sri Lanka. In the study a set of equations was developed corresponding to different temperatures to predict engine de-rating as a function of relative air humidity.  

    To achieve the required standard conditions in view of avoiding any de-rating of the engines, the charge air temperature needed to be reduced. For this purpose an absorption chiller system was proposed and designed to be operated with the waste heat recovery from the power plant. It proved that implementation of such a system is technically and economically feasible with a simple payback period of three and a half years on the capital invested.  

    This derived model was applied to actual operational data of the selected power plant and finally it was found a derated power of 417 kW could be fully recovered by conditioning the temperature and humidity of charge air to obtain the ISO conditions, giving a benefit equivalent fuel savings of 2233 kg/day.

  • 441.
    Kivumbi, Bernard
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Department of Biosystems Engineering, Gulu University, Gulu, Uganda.
    Olwa, J.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Menya, E.
    Techno-economic assessment of municipal solid waste gasification for electricity generation: A case study of Kampala City, Uganda2015In: E-journal CIGR, ISSN 1682-1130, E-ISSN 1682-1130, Vol. 17, no 4, p. 141-155Article in journal (Refereed)
    Abstract [en]

    This study was aimed at assessing the techno-economic potential of municipal solid waste (MSW) generated in Kampala City for electricity production through gasification. The quantity, characteristics and gasification parameters were determined. In addition, the gasifier- engine system components were sized, and an economic analysis was conducted to obtain the net present value (NPV) and the payback period. This study found that 523 t/d of MSW is collected in Kampala City. The biomass component of MSW was found to be 459.5 t/d with moisture content of 71.09% on as-received basis. The physical characteristics of the gasified biomass included 11.8% moisture content, 88.2% total solids, 25.9% ash content and 57.7 kg/m3 bulk density. The resulting normalized producer gas constituted 11.64% H2, 13.70% CO, 16.09% CO2, 54.12% N2, 4.45% CH4 and lower heating value (LHV) of 4.75 MJ/Nm3. The design fuel flow rate of 0.23 kg/s, specific gasification rate (SGR) of 5089.29 kg h-1 m-2 and specific energy demand of 42.75 GJ m-2 h-1 were obtained. This yields a net electrical power output of 425.17 kW with an overall efficiency of 15.6%. The net annual electricity generation from a single gasifier-engine system was found to be 2.97 GWh/a. The economic analysis for this system worth $887 333 of investment cost yielded a payback period of 6.57 years while the NPV at 6% interest rate was found to be nine years with a value of $316 47.

  • 442.
    Kizikoglu, Atahan Riza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Thermo-Economic Analysis of Solar Cooling/Heating Systems for Mediterranean Climates2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study focuses on the efficient use of solar energy for a certain region in the Mediterranean basin. Solar thermal energy becomes increasingly popular and the available solar market is investigated with the aim of selecting and assessing a pilot region for a promising solar application. The work herein focuses on estimating the potential of three different 100% solar-driven integrated systems to cover the entire cooling and heating demand of a selected single family house solely by solar energy. The three different alternative systems are presented and examined in detail for the actual case study application.

    The sample house within the chosen region is located on the south coast of Turkey. The entire thermal demand of this house for both cooling during summer and heating during winter has first been properly calculated. Characteristic features of the house and the typical design parameters for the region have been analyzed, as well as and their daily and annual variations. Heat loss and heating/cooling load calculations have been done with respect to these specifications and to ASHRAE regulations.

    After finding the building`s demands for the comfort temperature, the three different solar-driven systems are simulated for a practical application to the sample house. Required mechanical equipment and parasitic load consumption has been investigated for each system and investment cost analyses have been performed respectively. Simplified payback times for each alternative system are calculated and discussed. Payback period sensitivity analysis was attempted for two different locations featuring different grid pricing regulations.

    As a conclusion, feasibility analysis for the three examined types of solar-driven integrated heating and cooling systems has been attempted, which gives a good representation of the potential solar energy market in the Mediterranean region. Also some suggestions are offered to the companies which develop and market solar heating/cooling systems.

  • 443.
    Kodituwakku, Dinindu
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Effect of cooling charge air on the gas turbine performance and feasibility of using absorption refrigeration in the “Kelanitissa” power station, Sri Lanka2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the drawbacks of the gas turbine is that performance drops rapidly when ambient air temperature increases. This is a major drawback for gas turbines operated in a tropical country like Sri Lanka. In Colombo, commercial capital of Sri Lanka where this study was carried out, the ambient temperature typically varies between 25 0C and 32 0C.  

    The Kelanitissa gas turbine plant has single shaft gas turbines (GE MS5001 R) operated in open cycle which use diesel as fuel (designed for dual fuel) at a designed heat rate of 13,980 kJ/kWh and an electrical efficiency of 25.8%. The designed exhaust temperature is 513 0C.  

    In this study, Kelanitissa gas turbine unit was used for assessment of the performance with the changes in ambient air temperature. Two approaches were used to study this phenomenon. Firstly, the performance parameters were calculated by using actual data acquired by the operation history of the power plant. Secondly, the performance was analyzed using thermodynamic principles. Then results of the two approaches were compared.  

    The present performance values of the studied gas turbine, when compared to designed values, showed a very poor performance due to predominantly high ambient air temperatures. Originally designed for an efficiency of 25.8%, the maximum efficiency achieved at 33 0C was only 21.2%. This translates into a 4.6 %-point reduction in efficiency at 33 0C ambient temperature.  

    Estimated cooling load for the proposed inlet air cooling is 679.87 RT. Cost per unit cooling load of the reference 2-stage direct-fired absorption system is $751-721 (according to 600RT-700RT). For the worst case scenario the value of $751 per RT and exhaust system constituting 98% of the cost of a market-ready direct fired system (Broad Inc., 2008) can be used. This results in $736/RT as the cost for an absorption chiller system driven by exhaust heat. Total cost for the 679.87 RT system is $ 500,370.72 (Rs. 65Mn).  

    Payback period of the project is 11 years but the present value after 19 years is exceeding the project cost. Present value for 19 years is Rs. 65.86 Mn. Bringing down the temperature from an average of 270C to the ISO value of 15 0C would give Rs. 6 Mn of annual savings.

  • 444.
    Koldisevs, Jevgenijs
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Biogas production in rural areas of Mexico2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Mexico is highly dependent on fossil fuels. One of the governmental initiatives proposes to investigate the possibilities for biogas production in rural areas. Agricultural producers are highly susceptible to energy price variations and in most cases the steadily growing prices of electricity and fuels are lowering the profits and income of farmers. Environmental concerns about fossil fuels give additional stimulus towards a switch to more sustainable energy sources.

    Literature research on different types of biogas production technologies was carried out. Various anaerobic fermentation stages and techniques were studied in order to familiarise with particular features and to understand which of them will be more suitable for locations in rural Mexico, also taking into account the local conditions, availability of raw material, energy demands, etc.

    Mexico's agricultural policies and governmental support schemes were also studied. The agricultural sector in Mexico is strategically important and brings around 6% of the country's GDP. Security and availability of energy for the rural areas is crucial. A lot of improvements need to be done in this field to make this sector attractive for investors and more profitable for people who already work there. Such governmental organizations as SAGARPA - The Secretariat of Agriculture, Livestock, Rural Development, Fishing, and Food - and its support schemes and programs are aimed to help farmers both financially and technically to overcome the difficulties concerning this procedure.

    A detailed description of a proposed biogas production plant for a case study project at a milk farm in southern Mexico is presented in this study. Different stages and control strategies of biogas production as well as possibilities for biogas utilization in a small-scale CHP unit are assessed. Economical study was aimed to determine the financial flows of the sample project. A simplified economic analysis showed that the electricity produced in the biogas-driven CHP unit can compete with actual grid electricity prices. In addition, comparatively short payback time could be expected and the available governmental support schemes could be efficiency exploited for a commercially viable biogas production.

  • 445.
    Kolesnikov, Anton
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Experimental investigation of hydrocarbon formation and transformation under Earth´s upper mantle conditions2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The theory of the abyssal abiotic petroleum origin considers oil and natural gas to begenerated in the Earth’s upper mantle. Hydrocarbons migrate further through the deep faults into the Earth’s crust, where they can form oil and gas deposits in any kind of rock in any kind of structural position. Until recently one of the main obstacles for further development of this theory has been the lack of the data covering processes of generation and transformations of hydrocarbons.

    Experimental data, presented in this thesis, confirms the possibility of hydrocarbons formation from mantle inorganic compounds (water, Fe, CaCO3 or graphite) at temperature and pressure of the upper mantle (1500 K and 5 GPa). Experiments were carried out in CONAC high pressure device and multianvil apparatus BARS. Compositions of received gas mixtures were similar to natural gas. Quantity of hydrocarbons depended on the cooling regime of reaction mixture under pressure. Slow cooling favored higher quantity. We found that donor of carbon (CaCO3 or graphite) determines formation of “dry” (methane-rich) gas or “wet” (light hydrocarbons-rich) gas.

    Experiments in laser-heated diamond anvil cells showed that methane and ethane partially react under upper mantle thermobaric conditions (2-5 GPa, 1000-1500 K) to form mixture of hydrocarbons: methane, ethane, propane and n-butane – main compounds of natural gas. Similarity of final product mixture obtained from methane and ethane means thermodynamic stability of hydrocarbons in the thermobaric conditions of the upper mantle and equilibrium character of the observed processes.

  • 446.
    Kolesnikov, Anton
    et al.
    Carnegie Inst Washington, Geophys Lab.
    Kutcherov, Vladimir G.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Goncharov, Alexander F.
    Methane-derived hydrocarbons produced under upper-mantle conditions2009In: Nature geosicence, ISSN 1752-0894, Vol. 2, no 8, p. 566-570Article in journal (Refereed)
    Abstract [en]

    There is widespread evidence that petroleum originates from biological processes(1-3). Whether hydrocarbons can also be produced from abiogenic precursor molecules under the high-pressure, high-temperature conditions characteristic of the upper mantle remains an open question. It has been proposed that hydrocarbons generated in the upper mantle could be transported through deep faults to shallower regions in the Earth's crust, and contribute to petroleum reserves(4,5). Here we use in situ Raman spectroscopy in laser-heated diamond anvil cells to monitor the chemical reactivity of methane and ethane under upper-mantle conditions. We show that when methane is exposed to pressures higher than 2 GPa, and to temperatures in the range of 1,000-1,500 K, it partially reacts to form saturated hydrocarbons containing 2-4 carbons (ethane, propane and butane) and molecular hydrogen and graphite. Conversely, exposure of ethane to similar conditions results in the production of methane, suggesting that the synthesis of saturated hydrocarbons is reversible. Our results support the suggestion that hydrocarbons heavier than methane can be produced by abiogenic processes in the upper mantle.

  • 447. Korakianitis, T
    et al.
    Grantström, J
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wässingbo, Peter
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Massardo, A F
    Parametric performance of combined-cogeneration power plants with various power and efficiency enhancements2005In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 127, no 1, p. 65-72Article in journal (Refereed)
    Abstract [en]

    The design-point performance characteristics of a wide variety of combined-cogeneration power plants, with different amounts of supplementary firing (or no supplementary firing), different amounts of steam injection (or no steam injection), different amounts of exhaust gas condensation, etc., without limiting these parameters to present-day limits are investigated. A representative power plant with appropriate components for these plant enhancements is developed. A computer program,is used to evaluate the performance of various power plants using standard inputs for component efficiencies, and the design-point performance of these plants is computed. The results are presented as thermal efficiency, specific power, effectiveness, and specific rate of energy in district heating. The performance of the simple-cycle gas turbine dominates the overall plant performance; the plant efficiency and power are mainly determined by turbine inlet temperature and compressor pressure ratio; increasing amounts of steam injection in the gas turbine increases the efficiency and power; increasing amounts of supplementary firing decreases the efficiency but increases the power; with sufficient amounts of supplementary team injection the exhaust-gas condensate is sufficient to make up for water lost in steam injection; and the steam-turbine power is a fraction (0.1 to 0.5) of the gas-turbine power output. Regions of "optimum" parameters for the power plant based oil design-point power hot-water demand, and efficiency are shown. A method,for fuel-cost allocation between electricity and hot water is recommended.

  • 448.
    Koskela, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Uman, Emil
    Need assessment of electricity in Namibia: Prerequisites for implementation of a small scale wind turbine2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Namibia is one of the most sparsely populated countries with a total area of 825 600 km2. There are still many residents in the country without access to electricity, and with the present rapid technological development the need for electricity is increasing constantly. However, the expansion of the electricity grid is slow and costly, resulting in that many cannot afford to be connected and therefore a clear need for small scale electricity production has been identified. For this reason it was chosen to investigate this need closer and examine how a small-scale vertical axis wind turbine designed by InnovEd would meet the demand; also to identify suitable sites as well as purchase and maintenance schemes to promote wind turbines or other similar off-grid renewable energy solutions in rural Namibia. Additionally, an identification of possible variations and sensitivity of wind turbine performance and guidance and recommendation for future work were desired.

    In this study it was chosen to follow a grounded theory where the qualitative data was collected through interviews and general observations during a field trip in northern Namibia. The data were collected for two months in collaboration with the Creative Entrepreneurs Solutions.

    The results showed that the demand for electricity in rural areas was large but that a small amount of electricity can make a big difference to primarily run the most important devices. Lighting turned out to be most significant for the respondents, even if they would like to run all sorts of electrical equipment for everything if given a reliable and low-cost energy supply. This was in line with the literature that shows that it is normally the next step after meeting the most basic needs. It showed also that the price of electricity was of utmost importance for the local population.

    Finally, the authors recommend continuing to involve the users in the next stages of development where the major step would be to test the product with the users and to develop reasonable pricing and maintenance procedures. This should be followed by the creation of a local business and production plan for such products to reach a wider market as soon as possible.

  • 449.
    Koturbash, Taras
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Bicz, Agnieszka
    OPTEL Sp. z o.o. (Ltd).
    Bicz, Wiesław
    OPTEL Sp. z o.o. (Ltd).
    New instrument for measuring the velocity of sound in gases and quantitative characterization of binary gas mixtures2016In: Pomiary Automatyka Kontrola = Measurement Automation and Monitoring, ISSN 0032-4140, Pomiary Automatyka Kontrola; Measurement Automation Monitoring [PAK; MAM], ISSN 2450-2855, Vol. 65, no 08, p. 254-258Article in journal (Refereed)
    Abstract [en]

    A new instrument for precise measurements of velocity of sound in gases was developed and tested. The instrument implements improved velocity of sound measuring technique based on time-of-flight measurement of ultrasonic pulses.  The instrument was developed primarily for conducting measurements in natural gas, it can operate in wide ranges of natural gas compositions as well as other gas mixtures with velocity of sound parameter in range of 200 to 500 m/s.

    The instrument allows conducting measurement of velocity of sound propagation in various gas mixtures with average repeatability of equal to ±1 cm/s at normal conditions. The accuracy of measurement depends on calibration conditions and approach and has good agreement with theoretically calculated values. The instrument has a modular design of control unit and flow-through measuring chamber. The set of distinctive features and adjustable measuring parameters of the instrument allows further improving of applicability for other gases and gas mixtures and various measurement conditions.

    The instrument showed good performance in the task of quantitative characterization of binary gas mixtures by velocity of sound parameter.

  • 450.
    Koturbash, Taras
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Karpash, M.
    Darvai, I.
    Rybitskyi, I.
    Kutcherov, Vladimir
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics.
    Development of new instant technology of natural gas quality determination2013In: Proceedings of the ASME Power Conference 2013: presented at ASME 2013 power conference, July 29-August 1, 2013, Boston, Massachusetts, USA, ASME Press, 2013, p. V001T01A011-Conference paper (Refereed)
    Abstract [en]

    World experience shows that important factor in the calculations for natural gas consumption between suppliers and consumers is not only the volume of natural gas, but the quality indicators. With gas market liberalization, gas properties are expected to vary more frequently and strongly (composition, heating value etc.). Quality of natural gas is currently a topical issue, considering the steady increase of gas consumption in the world in recent decades. Existent chromatographs and calorimeters are very accurate in gas quality determination, but general expenditure and maintenance costs are still considerable. Market demands alternative lower cost methods of natural gas quality determination for transparent energy billing and technological process control. Investigation results indicate that heating value (HV) is a nonlinear function of such parameters as sound velocity in gas, N2 and CO 2 concentration. Those parameters show strong correlation with natural gas properties of interest (HV, density, Wobbe index), during analysis conducted on natural gas sample database. For solving nonlinear multivariable approximation task of HV determination, artificial neural networks were used. Proposed approach allowed excluding N2 concentration from input parameters with maintenance of sufficient accuracy of HV determination equal to 3.7% (with consideration of N2 concentration - 2.4%) on sample database. For validating of received results corresponding experimental investigation was conducted with reference analysis of physical and chemical parameters of natural gas samples by gas chromatography and followed superior HV calculation according to ISO 6976:1995. Developed experimental setup consist of measuring chamber with ultrasonic transducer, reflector, pressure, temperature and humidity sensors, ultrasonic inspection equipment for sound velocity measurements and CO2 concentration sensor with relevant instrument. The experimental setup allows measurement of sound velocity at 1MHz frequency and CO2 concentration in natural gas sample along with parameters control (temperature, humidity, pressure). The HV calculation algorithm was based on specially designed and trained artificial neural networks. Experimental investigation of proposed approach was conducted on 40 real samples of locally distributed natural gas. Obtained results, in comparison to reference values, showed absolute error in Lower HV (net calorific value) determination equal 166 kJ/m3, while relative error was equal 4.66%. Developed technology allows construction of autonomous instrument for instant natural gas quality determination, which can be combined with volume meters in order to provide transparent energy flow measurement and billing for gas consumers. Additionally it can be used for gas sensitive technological process control.

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