In industry, energy efficiency reduces operating cost and emissions to the environment whiles enhancing energy security. In order to ensure the sustainability of micro and small scale businesses in a developing country such as Ghana, measures that can ensure energy efficiency are therefore essential for these businesses to have a productive and economical operation that will ensure their sustainability. In this study, the potential of energy efficiency measures for micro and small scale businesses have been examined by performing industrial energy systems analysis on some selected micro and small scale businesses in Kumasi-Ghana through a practical study and administering of questionnaire about their energy consumption. Legislative instruments that are linked with energy use in Ghana were looked into. Some possible energy efficiency measures that could be adopted by these businesses have been analyzed. In this study it is established that energy supply to these businesses is not reliable and it is continuously becoming expensive. In addition, other findings were that value could be added to the processes of these businesses if they incorporate energy efficiency measures in their operations. The main driving force that will encourage these businesses to incorporate energy efficiency measures in their operation is the energy prices increase; therefore, their interest is the measures that could reduce their energy cost rather than the positive impacts that will come to the environment. In doing this renewable energy has the greatest potential in ensuring energy efficiency to these businesses. Finally, it is established that there are no specific legislations on energy use that will bring negative effects to these businesses and this could create enabling environment for private investors of energy efficiency.

Nowadays, due to global warming and the depletion of petroleum reserves, renewable energies have gained special prominence. At the moment, wind energy is the most successful renewable energy resource, and the technology to convert this wind energy into electricity has been very developed. As a consequence, the costs per kWh of generation have decreased and it has become a competitive alternative for conventional fossil-fuel power plants to generate electricity.However, a lot of factors and variables are involved in wind power generation. In the first part of this document, some of this factors like the Betz limit, the classification of wind turbines and its components, and the power curve of a wind turbine are explained.In the second part, the performance of a real wind farm is studied. The wind farm is called Es Milà, and it is located in an island called Minorca, in Spain.Firstly, a description of this wind farm and the energy and electricity in Minorca is made.Then, with meteorological and power data of 2007 a thorough study of its performance is completed. In this study, first of all some meteorological aspects like wind direction, wind velocity and its distribution are discussed.After that, the study focuses on electricity production, looking at the power curve, at the expected and the real production, and trying to explain a little of the reactive power.

<p>Wind tunnel studies of the wake behind a model wind turbine have been made in order to get a better understanding of wake development as well as the possibility to predict the power output from downstream turbines working in the wake of an upstream one. Both two-component hot-wire anemometry as well as particle image velocimetry (PIV) have been used to map the flow field. All three velocity components were measured both for the turbine rotor normal to the oncoming flow as well as with the turbine inclined to the free stream direction (the yaw angle was varied from 0 to 30 degrees). The measurements showed, as expected, a wake rotation in the opposite direction to that of the turbine. A yawed turbine is found to clearly deflect the wake flow to the side showing the potential of controlling the wake position by yawing the turbine. The power output of a yawed turbine was found to vary nearly as the square of the cosine of the yaw angle. The possibility to use active wake control by yawing an upstream turbine was evaluated and was shown to have a potential to increase the power output significantly for certain configurations. An unexpected feature of the flow was that spectra from the time signals showed the appearance of a low frequency fluctuation both in the wake and in the flow outside. This fluctuation was found both with and without free stream turbulence and also with a yawed turbine. The non-dimensional frequency (Strouhal number) was independent of the free-stream velocity and turbulence level but increases with the yaw angle. However the low frequency fluctuations were only observed when the tip speed ratio (or equivalently the drag coefficient) was high. This is in agreement with the idea that the turbine shed structures as a bluff body. It is hypothesized that the observed meandering of wakes in field measurements is due to this shedding.</p>

Current military-grade rifle body armor technology uses hard ballistic plates positioned on top of flexible materials, such as woven Kevlar® to stop projectiles and absorb the energy of the impact. However, absorbing the impact energy and stopping a rifle projectile comes at a cost to the wearer - mobility. In this thesis, a new concept for personal body armor is proposed - a semi-flexible hybrid body armor. This hybrid armor is comprised of two components that work as a system to effectively balance the flexibility offered by a soft fabric based armor with the protection level of hard plated armor. This work demonstrates techniques used to analyze and design the hybrid armor to be compliant with National Institute of Justice guidelines. In doing so, finite element analysis is used to simulate the effect of a projectile impacting the armor at various locations, angles, and velocities, while design of experiments is used to study the effect of these various impact combinations on the ability of the armor component(s) (including the wearer) to absorb energy. The flexibility and protection offered by the two component armor system is achieved by the use of proven technique and innovative geometry. For the analytical design, the material properties, contact area(s), dwell duration, and energy absorption are all carefully considered. This yields a lightweight but yet effective armor, which is estimated to weigh 36% less than the current military grade hard body armor. Using ANSYS, several simulations were conducted using finite element analysis, including a direct center impact, along with various other impacts to investigate possible weak points in the armor. In doing so, it is determined that only one of these impact locations is indeed a potential weak point. The finite element analysis continues to show that a rifle projectile impacting at an oblique angle reduces the energy transferred to the wearer by about 25% (compared to a direct impact). A design of experiments approach was used to determine the influence of various input parameters, such as projectile impact velocity and impact location. It is shown that the projectile impact velocity contributes 36% to the ability of the wearer to absorb energy, whereas impact velocity contributes only 13% to the energy absorbed by the top armor component. Furthermore, the analysis shows that the impact location is a highly influential factor (with a 69% contribution) in the energy absorption by the top armor component.

The work presented in this thesis is the result of the KTH CICERO project “Dynamic Engine Performance” in which the main objective was to develop simple models foremission formation. The demand for such models is increasing, mainly due to the tightening emission legislation for diesel engines which has lead to more complex engines and thereby more laborious development and calibration processes. Simple emission models can be a valuable tool during the development phase, e.g. when used with models for gas exchange - and after-treatment systems, and for precalibration of the engine control settings. Since engines in automotive application typically work under dynamic load, the main prerequisites were that the models should be comprehensive enough to handle the extreme conditions that can occur in engines during load transients but still simple enough to be used for calibration. Two main approaches have been used; one where the combustion and emission formation processes were modeled from the flame front and downstream using equilibrium chemistry. In the other approach, the entire mixing/entrainment process was modeled and emission formation was modeled with kinetic chemistry. Both approaches were found to meet the requirements but had different advantages; the first, simpler approach had shorter calculation time while the latter was more comprehensive and required less tuning. The latter also resulted in a model for heat release rate which can be useful as a stand-alone model and allows the emission models to be used for untested conditions. Another objective in this project was to identify techniques/instruments that can be used for emission measurements during transient operation since these are essential for understanding of emission formation in these conditions and as validation data for the emission models. / QC 20110502

<p></p><p>This report covers a feasibility study for a wind power project in Sri Lanka. Three potential sites for a wind farm are presented, out of which the Ambewela Cattle Farm is chosen as the most suitable. Limitations of a wind farm at the site, due to properties of the electrical grid and logistical issues, are examined and costs related to installing the wind farm are estimated. The maximum capacity of a wind farm is calculated to 45 MW. The payback period of the wind farm is calculated to 4.4 years. Environmental benefits of the wind farm are estimated in terms of avoided CO₂-emissions, which are calculated to 76 000 metric tonnes per year. The study concludes that a wind power project at the chosen site should be technically and financially feasible, if a wind turbine that matches certain logistical criteria can be found.</p><p> </p>

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Variable Speed Limits (VSL) are often used to improve traffic conditions on congested motorways. VSL can be implemented as mandatory or advisory. The objective of the thesis isto study in detail the effectiveness of VSL. The focus is on both, design parameters and conditions under which VSL are most effective. The MCS system on the E4 motorway inStockholm is used as a case study. The evaluation was conducted using empirical methods (including aggregate data from microwave sensors and other sources, and disaggregate data from a mobile study), and microscopic traffic simulation. The empirical analysis is based on before and after VSL data, including evaluation of individual measures of performance, and multivariate analysis in the form of the fundamental diagram, and speed-density relationships. The results from the empirical study are mixed with an indication that driver behavior has a strong impact on the effectiveness of the system. The microscopic traffic simulation analysis included the development of a platform for testing VSL and more generally motorway control strategies. The simulation platform was calibrated and validated with the empirical data and includes in addition to VSL, and Automatic Incident Detection (AID) system, the ALINEA ramp metering algorithm. The test-platform allows the testing of different control strategies and various combinations of control strategies, under different scenarios and in a controlled environment. The results from the simulation study indicate that driver compliance is an important factor and VSL performance quickly deteriorates as compliance rate drops. Hence, VSL should be implemented as mandatory instead of advisory. In addition, mandatory VSL can be effective both, under incident and moderately congested conditions. A combined VSL and ramp metering strategy can be most effective in reducing travel time, improving traffic conditions on the motorway. Furthermore, the results indicate that such a strategy also has the least impact on the flows entering the motorway from the ramps. / QC20100630

Today’s telecommunication cabinets use Electro Magnetic Compliance (EMC) screens in order to reduce electromagnetic noise that can cause some miss functions in electronic equipment. Many radio base stations (RBSs) use a 90-degree building architecture: the flow inlet is perpendicular to the EMC screen, which creates a complex flow, with a 90-degree air turn, expansions, compressions, perforated plates and PCBs. It is of great interest to study how the EMC screen interacts with the rest of components and analyze the total pressure drop and how much the flow pattern changes due to the placement of the screen. Velocity, pressure and temperature measurements as well as flow pattern visualizations have been carried out to gain good insight into the flow and heat transfer characteristics in a subrack model of an RBS. Furthermore, these measurements have been very useful for validating detailed CFD models and evaluating several turbulence models. Nowadays, industrial competition has caused a substantial decrease in the time-to-market of products. This fact makes the use of compact models in the first stages of the design process of vital importance. Accurate and fast compact models can to a great extent decrease the time for design, and thus for production. Hence, to determine the correlations between the pressure drop and flow pattern on the PCBs as a function of the geometry and the Reynolds number, based on a detailed CFD parametric study, was one objective. Furthermore, the development of a compact model using a porous media approach (using two directional-loss coefficients) has been accomplished. Two correlations of these directional loss coefficients were found as a function of the geometry and Reynolds number. / QC 20100630

The turbine technology improvements from 1980 onwards have considerably increased mechanical and thermal stresses on turbine oils which, cause oil oxidation and thereby turbine oil degradation (Livingstone et al., 2007; Sasaki &amp; Uchiyama, 2002). If the oil degradation problem is ignored, this might result in serious turbine system erratic trips and start-up operational problems (Overgaag et al., 2009). Oil oxidation by-products, in other words, sludge and varnish contaminants, lead stated turbine operation-tribological problems. Hence, sludge and varnish presence in turbine oil become a major reason for declining turbine reliability and availability. In the power generation industry, heavy-duty gas turbines as well as steam turbines have been lubricated with mineral based turbine oils for many decades (Okazaki &amp; Badal, 2005). First, generally Group I oils (mineral base oils produced by solvent extraction, dewaxing) were used. Nevertheless, this group of oils has lower oxidation resistance. Therefore, modern gas turbines demand oils which have better oil oxidation resistance, and lower sludge and varnish contaminants tendency (Hannon, 2009). Today, there are many turbine lubricants available on the market. Besides Group I oils, more and more Group II oils (mineral base oils produced by hydro cracking and hydro treating) are selected in service, and having increased oil oxidation resistance. However field inspections demonstrate that Group II oils also experience sludge and varnish problems as well as Group I oils. Primary reason for these phenomena is the antioxidant additive packages that are used in Group II oils (Overgaag et al., 2009). In any case with recent oil formulations, oil degradation products still exist in current turbine oils, and will continue to do so in natural process. These sludge and varnish contaminants are less than 1 micron in size. Thus, they can pass turbine oil system standard mechanical filters without obstruction. With regard to keep the turbine systems in best operational conditions, external turbine oil cleaning practices became crucial to remove these less than 1 micron size oil degradation products from turbine oils. Current effective method for removing the sludge and varnish is to use electrostatic oil cleaners (Moehle &amp; Gatto et al., 2007). Since the majority of turbine user and operator population have been shifted to use Group II based oils to counter the increased sludge and varnish problems, traditional oil cleaners became insufficient to remove sludge and varnish from Group II. (Due to Group II oils have different oil characteristics such as oil oxidation stability and solvency capability). With this awareness, thesis project is looking for ways to introduce and develop an Advanced Electrostatic Oil Cleaner to increase the availability and reliability figures of heavy-duty gas turbines against the rising amount of oil degradation products in modern formulated turbine oils. ECC (Electrostatic Cooled Cleaner) is an electrostatic oil cleaner device to clean and cool mineral based turbine oils for heavy-duty gas turbine applications by removing the sludge and varnish - oil contaminants from turbine oils. The basic principle of the ECC is based on the electrostatic force produced by parallel positioned electrodes which are charged with a high D.C. voltage. Oil contaminants- sludge and varnish have polar nature. Therefore, they are attracted by electrostatic forces whose intensity is proportional to the voltage applied. With the oil flowing in parallel to these electrodes, the polar particles in the oil (which is only neutral /no polar) are caught by filter media positioned between these electrodes. Small investments on advanced oil cleaner result in big savings on turbine system performance. Increased turbine availability and reliability predominantly reduce maintenance costs and risks besides, and thus maximizing revenue by extending heavy-duty gas turbine operational life. An introduced prototype of the ECC-D4 model was tested using two Group II and one Group I oils. The amounts of 200 liter (each) test oils were circulated approximately 300 times through the ECC-D4. In each 3 oil cleaning test sessions, it is proved that the oil insolubles content decreased approximately 40% in tested turbine oils within about 240 ECC-D4 operating hours. With taken base of heavy-duty gas turbine characteristics such as 400 MW power production capacity, annually 8000 operating hours, and 15000 liter oil reservoir volume; it is estimated that the ECC-D4 can extend the oil service-life from 24000 to 48000 operating hours (which is approximately the oil service end-life). In addition to that, assuming the ECC-D4 investment cost as 30k€, about 15k€ savings per year through the new turbine oil and component replacement costs, besides turbine operation profit losses. Moreover, the ECC-D4 returns on investment with a rate of 39 % for defined heavy-duty gas turbine. In general perspective of ECC-D4, it makes heavy-duty gas turbine infrastructure innovative, fully integrated and committed to fulfilling the need for clean, efficient, reliable power production practices in an environmental manner.