In this project, the correction factor of different solar panels of the laboratory of the University of Gävle, located in Sweden, is going to evaluated. The solar modules’working conditions are different from the ones used to test them in the laboratory. In the laboratory. the output energy of the modules is less than in working conditions,and therefore a correction factor is going to be calculated from the data collected, inorder to describe the factors that affect the performance of the solar modules.Also, the obtained correction factor validity for different PV systems it is going to be examined, determining which system has a better correction factor and the energy losses due to temperature, angle of incidence and micro invertor.

abstract: This is a two-part thesis: Part 1 of this thesis tests and validates the methodology and mathematical models of the International Electrotechnical Commission (IEC) 61853-2 standard for the measurement of angle of incidence (AOI) effects on photovoltaic modules. Flat-plate photovoltaic modules in the field operate under a wide range of environmental conditions. The purpose of IEC 61853-2 is to characterize photovoltaic modules' performance under specific environmental conditions. Part 1 of this report focuses specifically on AOI. To accurately test and validate IEC 61853-2 standard for measuring AOI, meticulous experimental setup and test procedures were followed. Modules of five different photovoltaic technology types with glass superstrates were tested. Test results show practically identical relative light transmission plots for all five test modules. The experimental results were compared to theoretical and empirical models for relative light transmission of air-glass interface. IEC 61853-2 states "for the flat glass superstrate modules, the AOI test does not need to be performed; rather, the data of a flat glass air interface can be used." The results obtained in this thesis validate this statement. This work was performed in collaboration with another Master of Science student (Surynarayana Janakeeraman) and the test results are presented in two masters theses. Part 2 of this thesis is to develop non-intrusive techniques to accurately measure the quantum efficiency (QE) of a single-junction crystalline silicon cell within a commercial module. This thesis will describe in detail all the equipment and conditions necessary to measure QE and discuss the factors which may influence this measurement. The ability to utilize a non-intrusive test to measure quantum efficiency of a cell within a module is extremely beneficial for reliability testing of commercial modules. Detailed methodologies for this innovative test procedure are not widely available in industry because equipment and measurement techniques have not been explored extensively. This paper will provide a literature review describing relevant theories and measurement techniques related to measuring the QE of a cell within a module. The testing methodology and necessary equipment will be described in detail. Results and conclusions provide the overall accuracy of the measurements and discuss the parameters affecting these measurements. / Dissertation/Thesis / M.S.Tech Technology 2013

<p>Biological treatment optimization aim at improving radiation therapy by accounting for the radiobiological tumour and normal tissues response properties when optimizing the dose delivery. Generally traditional methods, using only dosimetrical measures, disregard the nonlinear radiation response of different tumours and normal tissues. The accumulated knowledge on tissue response to radiation, in the form of more accurate dose response relations, cell survival models and their associated biological parameters, alongside with the tools for biological treatment plan optimization, has allowed the present investigation on the potential merits of biologically based treatment optimization in radiation therapy.</p><p>With a more widespread implementation of intensity modulated radiation therapy in the clinic, there is an increasing demand for faster and safer treatment delivery techniques. In this thesis biological treatment plan optimization, using the probability to achieve complication free tumour control as the quantifier for treatment outcome, was applied to radiation therapy of early breast cancer and advanced cervix cancer. It is shown that very conformal dose distributions can generally be produced with 3 or 4 optimally orientated coplanar intensity modulated beams, without having clinically significant losses in treatment outcome from the optimal dose distribution.</p><p>By using exhaustive search methods, the optimal coplanar beam directions for intensity modulated photon beams for early breast cancer and the optimal non-coplanar directions for an advanced cervix cancer were investigated. Although time consuming, exhaustive search methods have the advantage of revealing most features involving interactions between a small number of beams and how this may influence the treatment outcome. Thus phase spaces may serve as a general database for selecting an almost optimal treatment configuration for similar patients. Previous knowledge acquired with physically optimized uniform beam radiation therapy may not apply when intensity modulated biological optimization is used. Thus unconventional treatment directions were sometimes found.</p>

Biological treatment optimization aim at improving radiation therapy by accounting for the radiobiological tumour and normal tissues response properties when optimizing the dose delivery. Generally traditional methods, using only dosimetrical measures, disregard the nonlinear radiation response of different tumours and normal tissues. The accumulated knowledge on tissue response to radiation, in the form of more accurate dose response relations, cell survival models and their associated biological parameters, alongside with the tools for biological treatment plan optimization, has allowed the present investigation on the potential merits of biologically based treatment optimization in radiation therapy. With a more widespread implementation of intensity modulated radiation therapy in the clinic, there is an increasing demand for faster and safer treatment delivery techniques. In this thesis biological treatment plan optimization, using the probability to achieve complication free tumour control as the quantifier for treatment outcome, was applied to radiation therapy of early breast cancer and advanced cervix cancer. It is shown that very conformal dose distributions can generally be produced with 3 or 4 optimally orientated coplanar intensity modulated beams, without having clinically significant losses in treatment outcome from the optimal dose distribution. By using exhaustive search methods, the optimal coplanar beam directions for intensity modulated photon beams for early breast cancer and the optimal non-coplanar directions for an advanced cervix cancer were investigated. Although time consuming, exhaustive search methods have the advantage of revealing most features involving interactions between a small number of beams and how this may influence the treatment outcome. Thus phase spaces may serve as a general database for selecting an almost optimal treatment configuration for similar patients. Previous knowledge acquired with physically optimized uniform beam radiation therapy may not apply when intensity modulated biological optimization is used. Thus unconventional treatment directions were sometimes found.

The current energy situation is taking a turn towards renewable energies, due to the new pacts to curb global warming. These agreements, together with governmental aid, are facilitating an escalation in the production and improvement of new energy systems and the price decrease due to a larger-scale production. Within these energy alternatives, solar energy is found, specifically the subject to be treated in this project is photovoltaic energy, due to its exponential growth in the last 10 years, new tools are being developed for its monitoring and modelling. Therefore, the main objective of this thesis is to develop a method  for installation testing of a PV-system. The method should give the installed nominal power of the system and show if the maximum power point trackers work as expected. A large PV-system was installed on the roof of Gävle Arenaby during 2017. A measurement system for monitoring of the power of the system and of the solar irradiance was installed. Different parameters have been taken into account for the adjustment of the model that vary the performance of the system. These factors are: the irradiance received, the module temperature and the angle of incidence. It has been concluded that the results obtained indicate a correct adjustment of the theoretical power against the real power, which means, a correct operation of the generated model. Besides, the expected power follows a linear trend, reaching the power set by the manufacturer for Standard Test Conditions. The results show that the monitored modules-strings fulffill the promised performance and the method for installation testing work as expected. The linear correlation between corrected power and irradiance means that the maximum power point tracker in the inverter works independent of the power.

abstract: To increase the deployment of photovoltaic (PV) systems, a higher level of performance for PV modules should be sought. Soiling, or dust accumulation on the PV modules, is one of the conditions that negatively affect the performance of the PV modules by reducing the light incident onto the surface of the PV module. This thesis presents two studies that focus on investigating the soiling effect on the performance of the PV modules installed in Metro Phoenix area. The first study was conducted to investigate the optimum cleaning frequency for cleaning PV modules installed in Mesa, AZ. By monitoring the soiling loss of PV modules mounted on a mock rooftop at ASU-PRL, a detailed soiling modeling was obtained. Same setup was also used for other soiling-related investigations like studying the effect of soiling density on angle of incidence (AOI) dependence, the climatological relevance (CR) to soiling, and spatial variation of the soiling loss. During the first dry season (May to June), the daily soiling rate was found as -0.061% for 20o tilted modules. Based on the obtained soiling rate, cleaning PV modules, when the soiling is just due to dust on 20o tilted residential arrays, was found economically not justifiable. The second study focuses on evaluating the soiling loss in different locations of Metro Phoenix area of Arizona. The main goal behind the second study was to validate the daily soiling rate obtained from the mock rooftop setup in the first part of this thesis. By collaborating with local solar panel cleaning companies, soiling data for six residential systems in 5 different cities in and around Phoenix was collected, processed, and analyzed. The range of daily soiling rate in the Phoenix area was found as -0.057% to -0.085% for 13-28o tilted arrays. The soiling rate found in the first part of the thesis (-0.061%) for 20o tilted array, was validated since it falls within the range obtained from the second part of the thesis. / Dissertation/Thesis / Masters Thesis Engineering 2014

abstract: This is a two-part thesis: Part 1 characterizes soiling losses using various techniques to understand the effect of soiling on photovoltaic modules. The higher the angle of incidence (AOI), the lower will be the photovoltaic (PV) module performance. Our research group has already reported the AOI investigation for cleaned modules of five different technologies with air/glass interface. However, the modules that are installed in the field would invariably develop a soil layer with varying thickness depending on the site condition, rainfall and tilt angle. The soiled module will have the air/soil/glass interface rather than air/glass interface. This study investigates the AOI variations on soiled modules of five different PV technologies. It is demonstrated that AOI effect is inversely proportional to the soil density. In other words, the power or current loss between clean and soiled modules would be much higher at a higher AOI than at a lower AOI leading to excessive energy production loss of soiled modules on cloudy days, early morning hours and late afternoon hours. Similarly, the spectral influence of soil on the performance of the module was investigated through reflectance and transmittance measurements. It was observed that the reflectance and transmittances losses vary linearly with soil density variation and the 600-700 nm band was identified as an ideal band for soil density measurements. Part 2 of this thesis performs statistical risk analysis for a power plant through FMECA (Failure Mode, Effect, and Criticality Analysis) based on non-destructive field techniques and count data of the failure modes. Risk Priority Number is used for the grading guideline for criticality analysis. The analysis was done on a 19-year-old power plant in cold-dry climate to identify the most dominant failure and degradation modes. In addition, a comparison study was done on the current power plant (framed) along with another 18-year-old (frameless) from the same climate zone to understand the failure modes for cold-dry climatic condition. / Dissertation/Thesis / Masters Thesis Engineering 2015

This thesis presents an energy prediction tool for photovoltaic (PV) modules, based on the measure-correlate-predict principle. The tool allows quantification of the impact of the different environmental factors influencing PV device efficiency for different sites as they deviate from standardised test conditions and combines their effects for energy yield prediction of different module technologies operating in different climates. Amongst these environmental influences, the impact of angle of incidence has been particularly under-researched. In this work, a systematic investigation of the influence of angle of incidence on PV module performance is realised. This is achieved using both short-term module characterisation and long-term energy yield measurement campaigns. A customised purpose built dual axis tracker for mounting paired sets of modules on a fixed south-facing, 45-degree tilted rack is used to investigate the differences in module performance. The quality and quantity of the composition of the incident irradiance is described for various sky conditions at high latitude locations. Furthermore, an understanding of the entangled effects on photocurrent of both the angle of incidence and spectral variation is presented. This is achieved by analysing data from a system developed especially in this work which integrates an instantaneous all-sky mapping of irradiance from a monochromatic CCD camera with precision measurements of small-aperture normal irradiance from a collimated pyranometer in the short-term measurement campaign. The proposed energy prediction tool is validated using long-term datasets from several locations and is compared to other current methods. This was conducted under the European-funded PV-Catapult and IP Performance projects. The tool's prediction uncertainty falls within the ±5% for crystalline and ±10% for thin films, which is the same accuracy as other methods and within the measurement uncertainty of outdoor measurements.

The effect of varying the angle of incidence of a Gaussian beam from a He-Ne laser incident upon a large radius optical fiber is theoretically and experimentally investigated. The modes in a weakly-guiding, step index fiber were determined by using an analytical approximation technique to calculate the corresponding eigenvalues. An expression was developed for the fractional power per mode as a function of the angle of incidence for such a fiber. This expression was used to calculate the fractional power per mode for the lowest order 171 modes. This allowed the calculation of the fractional power per order and total power. By comparing these theoretical results to our experiment results, it is shown that the theoretical method is accurate at normal incidence and gives qualitative but not quantitative agreement at larger angles.

En un análisis sísmico tradicional, se considera principalmente la existencia de fuerzas sísmicas que actúan unidireccionalmente en dos o tres direcciones independientes. Sin embargo, se ha demostrado que la naturaleza del movimiento sísmico es errática, es decir, que las acciones sísmicas actúan en diferentes direcciones hacia la estructura. En el presente estudio, se analizó las respuestas de 4 modelos estructurales con una geometría arquitectónica escalonada usando un Análisis Modal Espectral (AME) y un Análisis Lineal Tiempo Historia (ALTH), con ángulos de incidencia con incrementos cada 10°, de manera que se evidencie los efectos de la bidireccionalidad sísmica frente al unidireccional a través de las respuestas máximas de los modelos. Para el ALTH, se consideraron 3 registros sísmicos ocurridos en Lima-Perú en un tipo de suelo rígido obtenidos a través de la red acelerográfica nacional peruana CISMID. Los resultados alcanzados muestran que, para el Análisis Modal Espectral (AME) el ángulo de incidencia mayor donde se presentan mayores repuestas es 45° para los 4 modelos, y para el ALTH los ángulos de incidencia son variables. Asimismo, en ambos análisis dinámicos, evaluando la bidireccionalidad sísmica se obtienen respuestas de 10 a 40% más que un análisis unidireccional. / In a traditional seismic analysis, it is mainly considered the existence of seismic forces that work unidirectionally in two or three independent directions. However, it has been demonstrated that the nature of the seismic movement is erratic, that is to say, that the seismic actions act in different directions towards the structure. In the present study, the responses of 4 structural models with a staggered architectural geometry were analyzed using a Spectral Modal Analysis (SMA) and a Linear Time History Analysis (ALTH), with incidence angles increased every 10°, so as to evidence the effects of the seismic bidirectionality against the unidirectional one through the maximum responses of the models. For the ALTH, 3 seismic records were considered, which occurred in Lima-Peru in a type of rigid soil obtained through the Peruvian national accelerographic network CISMID. The results achieved show that, for the Spectral Modal Analysis (SMA), the incidence angle where the greatest responses are presented is 45° for the 4 models, and for the ALTH the incidence angles are variable. Moreover, in both dynamic analyses, evaluating the seismic bidirectionality, responses are obtained from 10 to 40% more than a unidirectional analysis. / Trabajo de investigación