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. / Bangladesh har varit föremål för en svår energikris (bristande el- och gasnät) de senaste tre decennierna. Landsbygden, som innefattar 75 % av befolkningen, har varit särskilt drabbad. Trots landets elektrifieringsprogram av landsbygden är fotogenlampor den företrädande ljuskällan, medan förorenande och ohållbar träbaserad biomassa är praktiskt taget det enda alternativet för matlagning. Landsbygden kämpar samtidigt mot osäkert dricksvatten, på grund av utbredd arsenikförgiftning av brunnsvatten, med negativa hälsoeffekter som följd. Tillgång till ren energi och säkert dricksvatten är verkliga behov bland de fattiga på landsbygden, för ökad välfärd. Detta arbete antar ett integrerat tillvägagångssätt för att försöka lösa dessa problem genom småskalig polygenerering. Detta koncept länkar samman förnyelsebara energikällor av biomassa och sol med energibehoven, genom nya energiomvandlingssystem. Anaerobiska rötkammare för biogasproduktion är lovande för landsbygdsmiljö, även om det för närvarande råder en betydande klyfta mellan den tekniska och kostandseffektiva potentialen och faktisk implementering på grund av bristande tekniskt kunnande och tillgång på råmaterial, höga installations- och driftkostnader, och begränsade användartillämpningar. Intervjuundersökningar visar på problem i konstruktion, underhåll och drift av befintliga anaerobiska rötkammare. Särskilt den generella prestandan hos hushållsrötkammare identifieras som bristfällig. Utifrån dessa resultat föreslås en rad drift- och teknikförbättringar för att utnyttja rötkammare i polygenereringssystem.   Denna studie undersöker även en metod för småskalig och kostnadseffektiv arsenikrening av grundvatten genom membrandestillation med luftspalt (Air Gap Membrane Distillation, AGMD), vilket är en termiskt driven vattenreningsteknik. Resultat från en experimentell undersökning visar att den undersökta AGMD-prototypen är kapabel att uppnå utmärkt separationseffektivitet med hänsyn till arsenikrening. Parametriska studier med fokus på varierande kylvattentemperatur illustrerar möjligheten att integrera AGMD-teknik i diverse termiska system. Integrering av biogasproduktion med kraftproduktion och vattenrening är ett innovativt koncept som utgör kärnan av förstudierna utförda i detta arbete. En av studierna visar ett nytt koncept för biogasbaserad polygenerering och analyserar den techno-ekonomiska prestandan av metoden för att möta efterfrågan av elektricitet, matlagningsvärme och säkert dricksvatten för 30 hushåll i en Bangladeshisk by på landsbygden. De specifika tekniker som valts för energiomvandlingsstegen är följande: plugg-flödesrötkammare, förbränningsmotor och en AGMD-enhet. Termodynamisk utvärdering inklusive mass- och energibalans av systemet undersöktes tillsammans med produktionskostnaden för elektricitet, matlagningsgas, och säkert dricksvatten. Även återbetalningsperiod och internräntan undersöktes. För att bemöta energi- och arsenikproblemen i Bangladesh, indikerar resultaten att detta polygenereringssystem är mycket mer konkurrenskraftigt och lovande (med avseende på produktionskostnaderna) jämfört med andra tillgängliga tekniker. Ett viktigt problem för rötkammaren är tillgången till lokalt råmaterial, eftersom en ensam källa till råmaterial är opraktiskt för att tillgodose efterfrågan från både matlagning, belysning och vattenrening. I detta fall kan solceller vara ett potentiellt alternativ för integrerade hybridsystem. Teknisk värdering och optimering har genomförts för elektricitet med verktyget HOMER (Hybrid Optimization of Multiple Energy Resources), för ett polygenereringssystem beläget i byn Panipara i Faridpur. Resultaten visar att systement kan tillgodoses det dagliga elektricitetsbehovet och samtidigt producera 0.4 m3 matlagningsbränsle och 2-3 L/person rent dricksvatten. Kostnadsuppskattningar visar att denna metod är högst gynnsam jämfört med andra förnyelsebara alternativ (t ex vind-, vatten-, biobränslebaserad- eller geotermisk energi). / <p>QC 20170419</p> / SIDA – the Swedish International Development Cooperation Agency, Department for Research Cooperation, SAREC- project no. SWE-2011-135 / STEM-Fjärrsyn project 2014

The target of this diploma thesis is design of cogeneration unit with following requirements: • Installation of new unit instead of the old and used up one. • Electric energy supply within Supportive service – fast starts • Greening (replacement of coal with natural gas) At the beginning I deal with the current state of old unit. In the next part there is the design of new technological unit, which consists of design of boilers, gas engines, steam turbines. Final phase of the thesis includes economical analysis focused on setting of financial return.

The aim of this thesis is to design the condensation heat exchanger for stationary engine running on natural gas. Flue gas condenser is designed for universal use of refrigerants (i.e. water or 35% fusion ethylene-glycol in water) and their working temperatures. The work includes theoretical, computational and design part. In the attachment is located the drawing documentation to flue gas condenser.

<div>The commercial vehicle sector is an important enabler of the economy and is heavily dependent on fossil fuels. In the fight against climate change, reduction of emissions by improving fuel economy is a key step for the commercial vehicle sector. Improving fuel economy deals with reducing energy losses from fuel to the wheels. This study aims to analyze efficiency improvements for two systems that are important in reducing CO2 emissions - hybrid powertrains and natural gas engines. At first, a prototype series hybrid powertrain was analyzed based on on-highway data collected from its powertrain components. Work done per mile by the electrical components of the powertrain showed inefficient battery operation. The net energy delivery of the battery was close to zero at the end of the runs. This indicated battery was majorly used as an energy storage device. Roughly 15% of losses were observed in the power electronics to supply power from battery and generator to the motor. Ability of the hybrid system to capture regenerative energy and utilize it to propel the vehicle is a primary cause for fuel savings. The ability of this system to capture the regenerative energy was studied by modeling the system. The vehicle model demonstrated that the system was capturing most of the theoretically available regenerative energy. The thesis also demonstrates the possibility of reduction of vehicular level losses for the prototype truck. Drag and rolling resistance coefficients were estimated based on two coast down tests conducted. The ratio of captured regenerative to the drive energy energy for estimated drag and rolling resistant coefficients showed that the current system utilizes 4%-9% of its drive energy from the captured regenerative energy. Whereas a low mileage Peterbilt 579 truck could increase the energy capture ratio to 8%-18% for the same drive profile and route. Decrease in the truck’s aerodynamic drag and rolling resistance can potentially improve the fuel benefits.</div><div>The second study aimed to reduce the engine level pumping losses for a natural gas spark ignition engine by cylinder deactivation (CDA). Spark ignited stoichiometric engines with an intake throttle valve encounter pumping/throttling losses at low speed, low loads due to the restriction of intake air by the throttle body. A simulation study for CDA on a six cylinder natural gas engine model was performed in GT- Power. The simulations were ran for steady state operating points with a torque range 25-560 ftlbs and 1600 rpm. Two , three and four cylinders were deactivated in the simulation study. CDA showed significant fuel benefits with increase in brake thermal efficiency and reduction in brake specific fuel consumption depending on the number of deactivated cylinders. The fuel benefits tend to decrease with increase in torque. Engine cycle efficiencies were analyzed to investigate the efficiency improvements. The open cycle efficiency is the main contributor to the overall increase in the brake thermal efficiency. The work done by the engine to overcome the gas exchange during the intake and exhaust stroke is referred to the pumping losses. The reduction in pumping losses cause an improvement in the open cycle efficiency. By deactivating cylinders, the engine meets its low torque requirements by increase in the intake manifold pressure. Increased intake manifold pressure also resulted in reduction of the pumping loop indicating reduced pumping losses. A major limitation of the CDA strategy was ability to meet EGR fraction requirements. The increase in intake manifold pressure also caused a reduction in the delta pressure across the EGR valve. At higher torques with high EGR requirements CDA strategy was unable to meet the required EGR fraction targets. This limited the benefits of CDA to a specific torque range based on the number of deactivated cylinders. Some variable valve actuation strategies were suggested to overcome this challenge and extend the benefits of CDA for a greater torque range.</div><div><br></div>

This dissertation focuses on the introduction and development of an integrated model-based design and optimization platform to solve the optimal design and optimal control, or hardware and software co-design, problem for hybrid electric propulsion systems. Specifically, the hybrid and plug-in hybrid electric powertrain systems with diesel and natural gas (NG) fueled compression ignition (CI) engines and large Li-ion battery energy storage system (ESS) for propelling a hybrid electric marine vessel are investigated. The combined design and control optimization of the hybrid propulsion system is formulated as a bi-level, nested optimization problem. The lower-level optimization applies dynamic programming (DP) to ensure optimal energy management for each feasible powertrain system design, and the upper-level global optimization aims at identifying the optimal sizes of key powertrain components for the powertrain system with optimized control. Recently, Li-ion batteries became a promising ESS technology for electrified transportation applications. However, these costly Li-ion battery ESSs contribute to a large portion of the powertrain electrification and hybridization costs and suffer a much shorter lifetime compared to other key powertrain components. Different battery performance modelling methods are reviewed to identify the appropriate degradation prediction approach. Using this approach and a large set of experimental data, the performance degradation and life prediction model of LiFePO4 type battery has been developed and validated. This model serves as the foundation for determining the optimal size of battery ESS and for optimal energy management in powertrain system control to achieve balanced reduction of fuel consumption and the extension of battery lifetime. In modelling and design of different hybrid electric marine propulsion systems, the life cycle cost (LCC) model of the cleaner, hybrid propulsion systems is introduced, considering the investment, replacement and operational costs of their major contributors. The costs of liquefied NG (LNG), diesel and electricity in the LCC model are collected from various sources, with a focus on present industrial price in British Columbia, Canada. The greenhouse gas (GHG) and criteria air pollutant (CAP) emissions from traditional diesel and cleaner NG-fueled engines with conventional and optimized hybrid electric powertrains are also evaluated. To solve the computational expensive nested optimization problem, a surrogate model-based (or metamodel-based) global optimization method is used. This advanced global optimization search algorithm uses the optimized Latin hypercube sampling (OLHS) to form the Kriging model and uses expected improvement (EI) online sampling criterion to refine the model to guide the search of global optimum through a much-reduced number of sample data points from the computationally intensive objective function. Solutions from the combined hybrid propulsion system design and control optimization are presented and discussed. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. The resulting hybrid propulsion system with NG engine and Li-ion battery ESS presents a more economical and environmentally friendly propulsion system design of the tugboat. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. Other main contributions include incorporating the battery performance degradation model to the powertrain size optimization and optimal energy management; performing a systematic design and optimization considering LCC of diesel and NG engines in the hybrid electric powertrains; and developing an effective method for the computational intensive powertrain co-design problem. / Graduate

The aim of this Diploma thesis is a description of gas heat pump (GHP) technology and the possibility of their usage in real life. Also units from the major manufactures of GHP units in the Czech Republic and abroad are evaluated from technical and economical point of view. The thesis as well includes a part where is decided if it is better to further develop GHP units with higher or lower performance. In the last part of thesis are cooling circuits designed for both lower and higher performance, than performance of existing GHP unit Polo 100. As a result, the units with higher performance are more perspective. Therefore heat plate exchangers, which serve as a condenser and an evaporator, are designed for unit with higher performance.

Utsläpp från bilar har spelat stor roll de senaste decennierna. Detta har lett till ökad användning av Otto gasmotorer som använder naturgas som bränsle. Nya motordesigner behöver optimeras för att förbättra motorens effektivitet. Ett effektivt sätt att göra detta på är genom användningen av simuleringar för att minska ledtiden i motorutvecklingen. Verifiering och validering av simuleringarna spelar stor roll för att bygga förtroende för och förutsägbarhet hos simuleringsresultaten. Syftet med detta examensarbete är att föreslå förbränningsmodellparametrarna efter utvärdering av olika kombinationer av förbrännings- och tändmodeller för Otto förbränning, vad gäller beräkningstid och noggrannhet. In-cylindertrycksspår från simulering och mätning jämförs för att hitta den bästa kombinationen av förbrännings- och tändmodell. Inverkan av tändtid, antal motorcykler och randvillkor för simuleringsresultatet studeras också. Resultaten visar att ECFM-förbränningsmodellen förutsäger simuleringsresultaten mer exakt när man jämför med mätningarna. Effekten av tändningstiden på olika kombinationer av förbrännings- och tändningsmodell utvärderas också. Stabiliteten hos olika förbränningssimuleringsmodeller diskuteras också under körning för fler motorcykler. Jämförelse av beräkningstid görs även för olika kombinationer av förbrännings- och tändmodeller. Resultaten visar också att flamspårningsmetoden med Euler är mer känslig för cellstorlek och kvalitet hos simuleringsnätet, jämfört med övriga studerade modeller. Rekommendationer och förslag ges om nät- och simulerings-inställningar för att prediktera förbränningen på ett så bra sätt som möjligt. Några möjliga förbättringsområden ges som framtida arbete för att förbättra noggrannheten i simuleringsresultaten. / Emission from automobiles has been gaining importance for past few decades. This has gained a lot of impetus in search for alternate fuels among the automotive manufacturers. This led to the increase usage of Otto gas engine which uses natural gas as fuel. New engine designs have to be optimized for improving the engine efficiency. This led to usage of virtual simulations for reducing the lead time in the engine development. The verification and validation of actual phenomenon in the virtual simulations with respect to the physical measurements was quite important.  The aim of this master thesis is to suggest the combustion model parameters after evaluating various combination of combustion and ignition models in terms of computational time and accuracy. In-cylinder pressure trace from the simulation is compared with the measurement in order to find the nest suited combination of combustion and ignition models. The influence of ignition timing, number of engine cycles and boundary conditions on the simulation results are also studied. Results showed that ECFM combustion model predicts the simulation results more accurately when compare to the measurements. Impact of ignition timing on various combination of combustion and ignition model is also assessed. Stability of various combustion simulation models is also discussed while running for more engine cycles. Comparison of computational time is also made for various combination of combustion and ignition models. Results also showed that the flame tracking method using Euler is dependent on the mesh resolution and the mesh quality.  Recommendations and suggestions are given about the mesh and simulation settings for predicting the combustion simulation accurately. Some possible areas of improvement are given as future work for improving the accuracy of the simulation results.

Вопросы энергосбережения и повышения энергоэффективности являются одними из основных приоритетов государственной политики в деятельности органов исполнительной власти, как на федеральном, так и на региональном уровнях, т. к. Россия все еще принадлежит к группе стран с очень высокой энергоёмкостью ВВП. Цель диссертационного исследования заключается в разработке практических рекомендаций по повышению эффективности использования топливно-энергетических ресурсов в условиях реализации региональной политики энергосбережения. В работе рассмотрен топливно-энергетический комплекс Свердловской области, дана его характеристика и описаны его особенности. Проведен анализ использования энергоресурсов в различных сферах региональной экономики: рассмотрены энергоёмкость валового регионального продукта, объемы финансирования энергосберегающих мероприятий, удельные расходы топливно-энергетических ресурсов. Предложен проект по переводу автопарка транспортной компании с бензинового топлива на газомоторное с целью снижения потребления энергетических ресурсов и вредного воздействия на окружающую среду. Проведена оценка экономического и экологического эффектов реализации проекта. / Issues of energy conservation and energy efficiency are one of the main priorities of state policy in the activities of executive bodies, both at the federal and regional levels, since Russia still belongs to the group of countries with very high energy intensity of GDP. The purpose of the dissertation research is to develop practical recommendations to improve the efficiency of the use of fuel and energy resources in the context of the implementation of the regional energy conservation policy. The work considers the fuel and energy complex of the Sverdlovsk region, gives its characteristics and describes its features. The analysis of the use of energy resources in various areas of the regional economy is carried out: the energy intensity of the gross regional product, the volumes of financing energy-saving measures, the specific costs of fuel and energy resources are considered. A project is proposed to transfer the fleet of a transport company from gasoline to gas engine fuel in order to reduce the consumption of energy resources and harmful effects on the environment. An assessment of the economic and environmental effects of the project is presented.

<p> One primary focus on internal combustion engines is that these engines create multiple harmful exhaust gases that can cause damage to the environment. There are a number of advanced strategies that are currently being investigated to help reduce the amount of these harmful emissions that are emitted from IC engines. One such method of reducing harmful emission gases focuses on the three-way-catalyst. A three-way-catalyst (TWC) is an exhaust emission control device that is designed in such a way to take harmful exhaust gases and convert them into less harmful gases through various chemical reactions within the TWC. To help further the reduction of these harmful gases in the TWC, a novel two-loop control and estimation strategy is used. This control and estimation strategy involves the use of two loops with an inner-loop controller, outer-loop robust controller, and an estimator in the outer-loop. The estimator consists of a TWC model and an extended Kalman filter which is used to estimate the fractional oxidation state (FOS) of the TWC. This estimated FOS is then used by the robust controller, along with other parameters, to produce a desired engine lambda reference signal, λup. This desired lambda signal is then used by the inner-loop controller to control the engine lambda. Accurate control of lambda is important because the air-fuel-ratio range for a TWC to effectively achieve oxidation and reduction simultaneously is extremely narrow. Another primary focus in the field of internal combustion engines is designing and tuning advanced models within GT-Power that can accurately predict what will happen when running an actual engine. Designing, troubleshooting, and testing a GT-Power model is an extensive but rewarding process. Creating an accurate engine model can not only provide one with primary engine data that is also measurable in a test cell, but can also provide insight into some of the intricate processes and nature of the engine that are difficult or impossible to physically measure. Cummins has an extensive process of tuning GT-Power engine models. This process include items such as initial model calibrations, model discretizations, turbocharger tunings, and other items. Some of these processes are used to calibrate both Cummins Power Systems Business Unit engines as well as a Purdue B6.7N natural gas engine. </p>

The current work, through experimental and numerical investigations, analyses the process and cycle level deviations in engine response on fuelling multi-cylinder natural gas engines with producer gas. Producer gas is a low calorific value bio-derived alternative with composition of 19 ± 1% CO and H2, 2 ± 0.5 % CH4, 12 ± 1% CO2 and 46 ± 1% N2 and has thermo-physical properties significantly different from natural gas. Experimental investigations primarily address the energy balance (full cycle analysis) and in-cylinder response (process specific analysis) at various operating conditions covering naturally aspirated and turbocharged mode of operation with natural gas and producer gas. Numerical investigations are based on two thermodynamic scope mathematical models, a zero dimensional model (Wiebe function) and a quasi-dimensional model (propagating flame front heat release). A detailed diagnostic analysis on a six cylinder (E6) indicates, turbocharger mismatch, the first explicit impact of fuel thermo-physical property variation. Turbocharger matching and optimization resulted in a peak load of 72.8 kWe (BMEP 9.47) at a maximum brake torque ignition angles of 22 deg before TDC and compressor pressure ratio of 2.25. Engine energy distribution analysis indicates skewed energy balance with higher cooling load (in excess of 30%) as compared to fossil fuel operation. This is attributed to the presence of nearly 20% H2 which enhances the convective cooling through the higher thermal conductivity. Parametric variation of H2 fraction on a two cylinder engine (E2) with four different syngas compositions (mixture H2 varying from 7.1% to 14.2%) depicts enhanced cooling load from 33.5% to 37.7%. Process level comparison indicates significant deviations in the heat release profile compared to fossil fuels. It has been observed that with an increase in mixture hydrogen fraction (from 7.1% to 14.2%), the fast burn phase combustion duration reduces from 59.6% to 42.6% but the terminal stage duration increases from 25.5% to 48.9%. The enhanced cooling of the mixture (due to the presence of hydrogen), particularly in the vicinity of walls is argued to contribute towards the sluggish terminal phase combustion. Immediate implication of thermo-kinematic response variation is on the magnitude and sensitivity of combustion descriptors and the need for dependent control system calibration for producer gas fuelled operation is established. Descriptor analysis is extended to knocking pressure traces and a new simple methodology is proposed towards identifying the occurrence and regime of knock. Analysing the implications through numerical investigation, the influence of the altered thermo-kinematic response for producer gas fuelled operation impacts 0D simulations. Zero dimensional simulations fail with conventional coefficients requiring fuel specific coefficients. Based on fuel specific coefficients, the suitability of 0D model for the simulation of varying operating conditions ranging from naturally aspirated to turbo charged engines, compression ratios and different engine geometries is established. The analysis is extended to quasi-dimensional through the eddy entrainment and laminar burn up model. The choice of laminar flame speed and turbulent parameters is validated based on the assessment of the flame speed ratio (4.5 ± 0.5 for naturally aspirated operation, turbulent Reynolds number of 2500 ± 250 and 9.0 ± 1.0 for turbocharged operation, turbulent Reynolds number of 5250 ± 250). In the estimation of laminar flame speed, the limitation of GRIMech 3.0 mechanism for H2-CO-CH4 systems is explicitly established and GRIMech 2.11 is used to arrive at experimentally comparable results. In-cylinder engine simulation results covering parametric variation of load, ignition angle and mixture quality, for engine natural gas fuelled naturally aspirated operation and producer gas fuelled naturally aspirated and turbocharged after cooled are compared with experimental results. The quasi dimensional analysis is extended to simulate end gas auto-ignition and is validated by using experimental manifold conditions for turbocharged operation for which knock has been observed. Extending the model to a Waukesha cooperative fuels research engine, motor methane number of 110 is reported for standard composition producer gas. The use of quasi dimensional models with end gas reaction kinetics enabled for knock rating of fuels represents first of its kind initiative.