Photovoltaic (PV) systems are renewable, DC sources which provide non-linear output power with respect to PV panel operating voltage or current. The majority of PV sources yield poor conversion efficiencies between available solar radiation and electrical output. Additionally, they are expensive compared to other conventional power sources. Power electronic converters are capable of harvesting the most energy from these resources due to their configurability and high-efficiency. These converters form a power conditioning stage which allows for numerous control methods and energy management options. Traditional systems group PV sources into arrays in order to increase operating voltage and power to levels where it is practical to connect them to the utility grid. Grid-tied PV has the potential to increase the acceptance of PV energy by reducing end-user complexity — there are no batteries to manage and additional wiring can be kept to a minimum. However, these arrays of PV panels have significant drawbacks when they are subjected to non-ideal conditions. If a single panel is shaded, or covered in some way, then it will have greatly reduced output current. As a result, any other panel which is connected in series with the affected panel is also subject to the same output current reduction. This series grouping of panels may then indirectly affect other series-sets of panels which are connected in parallel to it by tricking the power electronics unit into operating at a point which is not the true maximum-power-point (MPP). By connecting a single PV panel to a single DC-DC converter, these array-effects can be avoided. Reliability and power output of the whole system should increase at the expense of additional hardware. The outputs of several PV-connected DC-DC converters can be connected either in series or in parallel. If they are connected in parallel, the converters must be able to boost the PV panel voltage up to a level greater than the desired utility-grid voltage. This thesis focuses on the design and control of a high-boost-ratio DC-DC converter suitable for use in a parallel-connected, grid-tied PV system. It demonstrates the feasibility of boost-ratios of up to 10 times while still achieving high efficiency. The design avoids the use of electrolytic capacitors in favor of smaller ceramic capacitors and a few large film-capacitors. A simplified model is proposed which is still suitable for use in the design of high-bandwidth control loops. Testing is done with a PV source showing preliminary results with a maximum-power-point-tracker (MPPT) which achieves very good steady-state performance. / Master of Science

This thesis discusses aspects of a novel solar concentrating photovoltaic / thermal (PV/T) collector that has been designed to produce both electricity and hot water. The motivation for the development of the Combined Heat and Power Solar (CHAPS) collector is twofold: in the short term, to produce photovoltaic power and solar hot water at a cost which is competitive with other renewable energy technologies, and in the longer term, at a cost which is lower than possible with current technologies. To the author’s knowledge, the CHAPS collector is the first PV/T system using a reflective linear concentrator with a concentration ratio in the range 20-40x. The work contained in this thesis is a thorough study of all facets of the CHAPS collector, through a combination of theoretical and experimental investigation. A theoretical discussion of the concept of ‘energy value’ is presented, with the aim of developing methodologies that could be used in optimisation studies to compare the value of electrical and thermal energy. Three approaches are discussed; thermodynamic methods, using second law concepts of energy usefulness; economic valuation of the hot water and electricity through levelised energy costs; and environmental valuation, based on the greenhouse gas emissions associated with the generation of hot water and electricity. It is proposed that the value of electrical energy and thermal energy is best compared using a simple ratio. Experimental measurement of the thermal and electrical efficiency of a CHAPS receiver was carried out for a range of operating temperatures and fluid flow rates. The effectiveness of internal fins incorporated to augment heat transfer was examined. The glass surface temperature was measured using an infrared camera, to assist in the calculation of thermal losses, and to help determine the extent of radiation absorbed in the cover materials. FEA analysis, using the software package Strand7, examines the conductive heat transfer within the receiver body to obtain a temperature profile under operating conditions. Electrical efficiency is not only affected by temperature, but by non-uniformities in the radiation flux profile. Highly non-uniform illumination across the cells was found to reduce the efficiency by about 10% relative. The radiation flux profile longitudinal to the receivers was measured by a custom-built flux scanning device. The results show significant fluctuations in the flux profile and, at worst, the minimum flux intensity is as much as 27% lower than the median. A single cell with low flux intensity limits the current and performance of all cells in series, causing a significant drop in overall output. Therefore, a detailed understanding of the causes of flux non-uniformities is essential for the design of a single-axis tracking PV trough concentrator. Simulation of the flux profile was carried out using the ray tracing software Opticad, and good agreement was achieved between the simulated and measured results. The ray tracing allows the effect of the receiver supports, the gap between mirrors and the mirror shape imperfections to be examined individually. A detailed analytical model simulating the CHAPS collector was developed in the TRNSYS simulation environment. The accuracy of the new component was tested against measured data, with acceptable results. A system model was created to demonstrate how sub components of the collector, such as the insulation thickness and the conductivity of the tape bonding the cells to the receiver, can be examined as part of a long term simulation.

Today many buildings and it´s nearby surroundings are designed to achieve some kind of environmental goal.The issue concerning energy consumption is currently at focus and it is relevant that we start increase the share of renewable energy. Solar energy is an infinite resource and should therefore be considered when selecting an energy supplier.   Uppsala University hospital is facing major restructuring when parts of the existing buildings will be refurbished and a large new building will be constructed. White Architects have developed a study concerning the new building and for some of the existing buildings on the hospital campus. Uppsala County requires tough energy measures and wants the new building to be classified as an eco-building in Whites following work. The classifications will involve high energy source requirements.   This work has been conducted to see if solar power can be envisaged as a supplementary energy source for the University hospital and also to investigate the aesthetic impact of solar cells on the new building. In this report, solar cells integrated on the facade and PV modules on the roofs have been studied. Focus has been to evaluate the potential of what each option can produce and what opportunity they have to become an intrinsic part of the architecture   The type of solar cell module, which in this case study has been proven to generate most electricity is stand-alone modules on roofs. These are however, more difficult to reconcile with the architecture. Solar cells on the facades should therefore still be considered as an alternative application.The result shows that the potential energy that can be generated by solar panels on the new building is large but not in relation to hospital´s electricity use. It is for that reason questionable whether solar installation, applied on the new building, can be seen as a good additional source of energy or if it will more become a matter of public relations.

No description available.

In the last few years, unglazed transpired solar collectors (UTCs) have proven to be an effective and viable method of reducing HVAC loads and building energy consumption. With the growing interest in PV/Thermal collectors, a study of a PV/Thermal UTC with PV cells mounted directly on the absorber was carried out. In the first part of this project, a TRNSYS model was developed to predict the performance of a PV/Thermal UTC. It was based on an actual UTC model, but modifications were made to account for the wind, the presence of PV cells and the corrugated shape of the plate. Simulations showed that mounting the cells only on the top surfaces of the corrugations prevented the cells from being shaded by the collector and consequently, presented the greatest potential. With this configuration, it was found that the addition of PV cells on the UTC decreased the thermal energy savings by 5.9 %, but that 13.6 % of the thermal energy savings could be recovered in the production of electricity. In the second part of the study, a prototype of a PV/Thermal UTC was constructed and tested outdoors. It was found that 10 % more electricity was obtained when the fan was turned on than for zero flow conditions. It was also observed that at greater air suction rates, more cooling of the panel was achieved and potentially higher electrical power could be produced. The effect of the PV cells on the collector thermal performance could not be quantified, however, due to the small portion of PV cells on the whole collector area. TRNSYS simulations were performed using the prototype parameters and the weather data of some experimental days. The results predicted by the component developed showed similar trends as the experimental results. The predictions were, however, not within the experimental uncertainties. The deviation in the results was attributed to the fact that the wind heat losses were not estimated accurately by the model and the non-uniform suction at the panel surface that prevented the prototype tested to work at its optimal performance.

No description available.

In the last few years, unglazed transpired solar collectors (UTCs) have proven to be an effective and viable method of reducing HVAC loads and building energy consumption. With the growing interest in PV/Thermal collectors, a study of a PV/Thermal UTC with PV cells mounted directly on the absorber was carried out. In the first part of this project, a TRNSYS model was developed to predict the performance of a PV/Thermal UTC. It was based on an actual UTC model, but modifications were made to account for the wind, the presence of PV cells and the corrugated shape of the plate. Simulations showed that mounting the cells only on the top surfaces of the corrugations prevented the cells from being shaded by the collector and consequently, presented the greatest potential. With this configuration, it was found that the addition of PV cells on the UTC decreased the thermal energy savings by 5.9 %, but that 13.6 % of the thermal energy savings could be recovered in the production of electricity. In the second part of the study, a prototype of a PV/Thermal UTC was constructed and tested outdoors. It was found that 10 % more electricity was obtained when the fan was turned on than for zero flow conditions. It was also observed that at greater air suction rates, more cooling of the panel was achieved and potentially higher electrical power could be produced. The effect of the PV cells on the collector thermal performance could not be quantified, however, due to the small portion of PV cells on the whole collector area. TRNSYS simulations were performed using the prototype parameters and the weather data of some experimental days. The results predicted by the component developed showed similar trends as the experimental results. The predictions were, however, not within the experimental uncertainties. The deviation in the results was attributed to the fact that the wind heat losses were not estimated accurately by the model and the non-uniform suction at the panel surface that prevented the prototype tested to work at its optimal performance.

The municipality of Borlange is planning to build a new modern, social and an ecologically sustainable district due to an increase in the city’s population. Over 1200 homes shall be built for people from all sections of the society. Due to such high levels of migration into the city, it is of utmost importance for the society to ensure that all the new constructions would be energy efficient and focused towards the goal of creating a sustainable society. The main objective of this study is to understand the importance of planning for Photovoltaics (PV) in new areas and performing a series of simulations for different scenarios with varying degrees of PV penetration for the planned residential area of Jakobsgardarna in Borlänge, Sweden.   This was achieved by determining the load profiles for all buildings by thorough investigation over the previous works in the analysis of household demand loads and calculating the available roof area in several orientations with the help of model maps drawn to scale. Due to varied types of roofs and their structures, it was assumed that all buildings have a similar roof structure i.e. tilted roofs having a tilt of 30°. Batch simulation was performed in PVSyst for a base case scenario which provides the reference point for determining the total PV power and the total PV output in all orientations.   The PV penetration is measured in terms of energy by dividing the total PV output with the annual demand load. Various scenarios of PV penetration are created based on the available roof areas at particular roof orientations. It can be observed that the level of PV penetration is highly dependent on the orientation of roofs. A 17% of PV penetration is observed when PV is installed only on South-facing roofs while the PV penetration reduces drastically to 9% when PV is installed only on East-West facing roofs even though there isn’t a linear reduction in the available roof area.

abstract: Due to the increasing trend of electricity price for the future and the price reduction of solar electronics price led by the policy stimulus and the technological improvement, the residential distribution solar photovoltaic (PV) system’s market is prosperous. Excess energy can be sold back to the grid, however peak demand of a residential customer typically occurs in late afternoon/early evening when PV systems are not a productive. The solar PV system can provide residential customers sufficient energy during the daytime, even the exceeding energy can be sold back to the grid especially during the day with good sunlight, however, the peak demand of a regular family always appears during late afternoon and early evening which are not productive time for PV system. In this case, the PV customers only need the grid energy when other customers also need it the most. Because of the lower contribution of PV systems during times of peak demand, utilities are beginning to adjust rate structures to better align the bills paid by PV customers with the cost to the utility to serve those customers. Different rate structures include higher fixed charges, higher on-peak electricity prices, on-peak demand charges, or prices based on avoided costs. The demand charge and the on-peak energy charge significantly reduced the savings brought by the PV system. This will result in a longer the customer’s payback period. Eventually PV customers are not saving a lot in their electricity bill compare to those customers who do not own a PV system. A battery system is a promising technology that can improve monthly bill savings since a battery can store the solar energy and the off-peak grid energy and release it later during the on-peak hours. Sponsored by Salt River Project (SRP), a smart home model consists 1.35 kW PV panels, a 7.76 kWh lithium-ion battery and an adjustable resistive load bank was built on the roof of Engineering Research Center (ERC) building. For analysis, data was scaled up by 6/1.35 times to simulate a real residential PV setup. The testing data had been continuously recorded for more than one year (Aug.2014 - Oct.2015) and a battery charging strategy was developed based on those data. The work of this thesis deals with the idea of this charging strategy and the economic benefits this charging strategy can bring to the PV customers. Part of this research work has been wrote into a conference paper which is accepted by IEEE PES General Meeting 2016. A new and larger system has been installed on the roof with 6 kW PV modules and 6 kW output integrated electronics. This project will go on and the method come up by this thesis will be tested. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2016

Currently, a sustainable energy transition is underway to reduce CO2 emissions. To meet the targets outlined in international agreements like the Kyoto Protocol, a rapid expansion of renewable energy sources, particularly photovoltaic (PV) systems, is underway. Due to photovoltaic technology's rapid development and integration, reliable testing and evaluation methods are essential. This master's thesis is dedicated to developing a PV system simulator to study the PV systems. PV simulators serve as precious tools due to their capacity to control and replicate the environmental conditions experienced by PV panels. Consequently, these simulators facilitate thorough research, design refinement, and PV system performance assessment. The developed PV system simulator is essentially a PV remote lab, offering the capability to monitor, gather data, and evaluate the performance of the PV system remotely. The proposed system's flexibility and scalability enable its application to study various types of PV installation. The PV remote lab is expected to be a training centre for students and industry professionals. A comprehensive literature review on photovoltaic technology has been undertaken. Following the literature review, the different components that form a PV system have been defined and selected. The system will have a communication block to achieve a flexible and scalable PV remote lab. In this way, different configurations of the PV panels and different system outputs can be implemented. This commutation block can be remotely controlled using an Arduino, and an interface can be designed where the desired PV panel configurations and system outputs can be selected. In this interface, visualising the tests' results will also be possible. / För närvarande pågår en hållbar energiomställning för att minska koldioxidutsläppen. För att uppfylla de mål som fastställts i internationella avtal som Kyotoprotokollet pågår en snabb utbyggnad av förnybara energikällor, särskilt solcellssystem (PV). På grund av solcellsteknikens snabba utveckling och integration är tillförlitliga test- och utvärderingsmetoder av avgörande betydelse. Denna masteruppsats handlar om att utveckla en solcellssimulator för att studera solcellssystem. PV-simulatorer är värdefulla verktyg eftersom de kan kontrollera och återskapa de miljöförhållanden som PV-panelerna utsätts för. Följaktligen underlättar dessa simulatorer grundlig forskning, designförbättring och bedömning av PV-systemets prestanda. Den utvecklade PV-systemsimulatorn är i grunden ett fjärrstyrt PV-labb som gör det möjligt att övervaka, samla in data och utvärdera PV-systemets prestanda på distans. Det föreslagna systemets flexibilitet och skalbarhet gör att det kan användas för att studera olika typer av solcellsinstallationer. PV-fjärrlabbet förväntas bli ett utbildningscenter för studenter och yrkesverksamma inom branschen. En omfattande litteraturgenomgång om solcellsteknik har genomförts. Efter litteraturgenomgången har de olika komponenterna som bildar ett solcellssystem definierats och valts ut. Systemet kommer att ha ett kommunikationsblock för att uppnå ett flexibelt och skalbart PV-fjärrlabb. På så sätt kan olika konfigurationer av solcellspanelerna och olika systemutgångar implementeras. Detta kommutationsblock kan fjärrstyras med en Arduino och ett gränssnitt kan utformas där de önskade konfigurationerna av solcellspaneler och systemutgångar kan väljas. I detta gränssnitt kommer det också att vara möjligt att visualisera testresultaten.