This master’s thesis is dealing with the plan of reconstruction of the house in an effort to get closer to "near zero building". Total heat loss along with calculation of the cost of the house operation and the energy performance of buildings were computed for the given house. Then we have enclosed suggestions of individual methods of building´s insulation (replacing of windows, doors and gates, insulation of exterior walls, roof and ceiling between floor and attic) and a draft of a new technical building services (forced ventilation with heat recovery, photovoltaic system and heat pump). Furthermore, the suitability of the original heating system was evaluated and the also the energy performance for the renovated building was analyzed during the reconstruction. An economic evaluation was calculated for each method of reconstruction, together with the new green subsidy programme. At the end of the dissertation is drawn up the economic evaluation of the whole proposed reconstruction, together with an assessment, what class of the building we have achieved according to its the energy intensity.

The aim of this master project is to design a nearly zero-energy building of kindergarten. The kindergarten is designed as one storey building with capacity of 40 children split into two playrooms. Playrooms are separated and each of them has own sanitary facilities and locker room. Playrooms have large windows with external blinds on the south to provide solar gains. There is horizontal sun breaker above the windows which prevent overheating in summer. Load bearing walls are made of sand lime blocks. Walls are insulated with mineral wool board. Roof ceiling is made of prestressed concrete slabs. The building has a flat extensive green roof. The second task of the project includes design of lighting, rainwater harvesting, HVAC, source of heat and photovoltaic system. The third part is theoretical and includes searching for an ideal source of energy for the building. There are two types of heating compared such as gas boiler and a groundwater heating pump. The main software used for the project is Revit.

[pt] No Brasil, existem muitos projetos em sistemas fotovoltaicos, e a projeção para os próximos anos é de crescimento devido incentivos governamentais e os elevados preços das tarifas de energia. Associado a isso, o mercado de armazenamento de energia com baterias de íons de lítio tem se mostrado promissor devido a uma considerável queda nos preços dessas baterias nos últimos anos. Isso pode representar uma oportunidade para o mercado de sistemas fotovoltaicos quando os incentivos acabarem. Este trabalho propõe um modelo PLIM (Programação Linear Inteira Mista) estocástico para dimensionar um sistema fotovoltaico integrado com armazenamento de energia em baterias para grandes consumidores de energia, usando cenários de geração e consumo, podendo considerar diferentes modalidades tarifárias. As variáveis de decisão são o número de painéis, inversores, baterias, a operação diária do sistema de armazenamento e a demanda contratada do consumidor. A função objetivo busca minimizar o custo de investimento no sistema fotovoltaico, baterias e fatura de energia. A abordagem proposta será analisada sob diferentes premissas, uma com incentivos governamentais sobre a anergia injetada na rede e outra na qual a injeção de energia na rede não é permitida, a fim de avaliar a importância das baterias para manter a atratividade econômica do sistema fotovoltaico. Os resultados indicaram que o efeito sinérgico do sistema fotovoltaico com baterias potencializa a arbitragem, que está relacionada com a diferença entre as tarifas de energia de ponta e fora ponta. Isso ocorre principalmente com operação zero exportação porque somente assim o consumidor é livre para escolher a capacidade do seu sistema fotovoltaico, que hoje é limitado no Brasil quando o sistema é conectado na rede de distribuição. / [en] In Brazil, there are many projects in photovoltaic systems, and the projection for the coming years is positive due to the government incentives and the expensive energy tariffs. Associated with this, the Lithium-ion battery storage systems market has been promising due to a significant drop in battery prices in the last few years. This may represent an opportunity for the photovoltaic system market when the incentives run-out. This work proposes a stochastic mixed integer linear programming (MILP) model to design a photovoltaic system integrated with battery energy storage for big electricity consumers, using generation and consumption scenarios, being able to consider different Time-of-Use tariffs. The decision variables are the number of panels, inverters and batteries, its daily operation and the power demand contracted. The objective function aims to minimize the cost of investment, in the photovoltaic system, batteries and electricity bill. The proposed approach will be analyzed under different assumptions, one with the government incentive about injected surplus and another in which the injection into the network is not possible, in order to assess the importance of a storage system to keep the economic attraction of the photovoltaic system. Results indicated that the synergic effect of the photovoltaic system and battery potentialize the arbitrage, which is related to the difference between peak and off-peak energy tariff. This occurs, mainly with Zero Export operation because only this way the consumer is free to choose the capacity of the photovoltaic system, which is limited in Brazil when the system is allowed to inject energy into the network.

Energy from solar photovoltaic (PV) are generated as direct current (DC) and almost all of today’s electrical loads in residential buildings, household appliances and HVAC system (Heating Ventilation and Air-conditioning) are operated on DC. For a conventional alternating current (AC) distribution system this requires the need for multiple conversion steps before the final user-stage. By switching the distribution system to DC, conversion steps between AC to DC can be avoided and, in that way, losses are reduced. Including a battery storage–the system’s losses can be reduced further and the generated PV energy is even better utilised. This thesis investigates and quantifies the energy savings when using a direct current distribution topology in a residential building together with distributed energy generation from solar photovoltaic and a battery storage. Measured load and PV generation data for a single-family house situated in Borås, Sweden is used as a case study for the analysis. Detailed and dynamic models–based on laboratory measurements of the power electronic converters and the battery–are also used to more accurately reflect the system’s dynamic performance. In this study a dynamic representation of the battery’s losses is presented which is based on laboratory measurements of the resistance and current dependency for a single lithium-ion cell based on Lithium iron phosphate (LFP). A comparative study is made with two others, commonly used, loss representations and evaluated with regards to the complete system’s performance, using the PV and load data from the single-family house. Results show that a detailed battery representation is important for a correct loss prediction when modelling the interaction between loads, PV and the battery. Four DC system topologies are also modelled and compared to an equivalent AC topology using the experimental findings from the power electronic converters and the battery measurements. Results from the quasi-dynamic modelling show that the annual energy savings potential from the suggested DC topologies ranges between 1.9–5.6%. The DC topologies also increase the PV utilisation by up to 10 percentage points, by reducing the associated losses from the inverter and the battery conversion. Results also show that the grid-tied converter is the main loss contributor and when a constant grid-tied efficiency is used, the energy savings are overestimated.

The deployment of large-scale photovoltaic (PV) systems is rising in the Swedish power system, both in quantity and in system size. However, the intermittent characteristics of the PV production raises questions concerning the stability in the electric power grid, and power output fluctuations from the PV systems can lead to voltage quality issues. Hence, the distribution system operator E.ON Energidistribution and the solar energy developer company Solkompaniet are interested in investigating potential challenges and possibilities related to the integration of large-scale PV systems in the electric power grid. This thesis studies fast voltage variations in the electric power grid due to output fluctuations from large-scale PV systems, and examines the possibility to mitigate the voltage variations by reactive power support strategies in the PV inverters. Four studies are carried out to investigate the prerequisites for establishing large-scale PV systems. Firstly, a worst-case study considering eight existing substations in the electric power grid as well as a new substation is carried out, to examine the impact of different parameters on the voltage variations. Parameters such as transformer operation mode, location of the point of connection, switching mode and load capacity are compared in the study. Further, time series calculations are done to investigate the voltage variations over one year, and a study with an oversized PV system is done to investigate the possibility for increasing the PV capacity without grid reinforcements. Lastly, a study is performed with reactive power compensation from the PV inverters to examine the possibility to maintain a stabilized voltage level at the point of connection. The studies are performed in E.ONs network model in the power system simulator software PSS/E, with data for the transmission grid, the regional grid, and parts of the distribution grid included. PV systems with a rated capacity from 32 MWp and upwards are connected to substations in the regional grid, where fast voltage variations on nominal voltage levels of 20/10 kV are studied and evaluated from the perspective of the power producer. From this thesis, it can be concluded that neither of the implemented studies results in voltage variations that violate E.ONs technical requirements on fast voltage variations in the point of connection. Further, the results from the worst-case study show the importance of analysing the specific system of interest when connecting PV systems, since the properties of the existing system have an impact on the voltage variations. The time series calculations show that the voltage variations over a time period of one year are highly influenced by the PV production and the load capacity in the substation, and the study with an oversized PV system shows the possibility for increasing the PV capacity without curtailing large amounts of active power. Finally, the study with reactive power compensation concludes that grid support strategies in the PV inverters may be a key solution for making optimal use of the existing electric power grid and enabling the continued expansion of large-scale PV systems in the Swedish power system. / Utbyggnaden av storskaliga solcellsanläggningar (PV) ökar i det svenska kraftsystemet, både i kvantitet och i systemstorlek. De intermittenta egenskaperna hos energiproduktionen väcker emellertid frågor angående stabiliteten i elnätet, och effektförändringar från anläggningarna kan leda till spänningskvalitetsproblem. Därför är distributionssystemoperatören E.ON Energidistribution och solenergiföretaget Solkompaniet intresserade av att undersöka potentiella utmaningar och möjligheter relaterade till integrationen av storskaliga solcellsanläggningar i elnätet. Detta examensarbete studerar snabba spänningsvariationer i elnätet till följd av effektförändringar från storskaliga solcellsanläggningar, och undersöker möjligheten att mildra spänningsvariationerna genom strategier för reaktiv effektreglering i växelriktare.  Fyra studier genomförs för att undersöka förutsättningarna för att etablera storskaliga solcellsanläggningar. För det första genomförs en värsta-fallstudie med beaktande av åtta befintliga stationer i elnätet samt en ny station, för att undersöka olika parametrars påverkan på spänningsvariationerna. Parametrar som transformatorns driftläge, plats för anslutningspunkten, omkopplingsläge och lastkapacitet jämförs i studien. Vidare görs tidsserieberäkningar för att undersöka spänningsvariationerna över ett år, och en studie med en överdimensionerad solcellsanläggning görs för att undersöka möjligheten att öka solcellskapaciteten utan elnäts- förstärkningar. Slutligen genomförs en studie med reaktiv effektkompensation från växelriktare för att undersöka möjligheten att upprätthålla en stabiliserad spänningsnivå i anslutningspunkten. Studierna utförs i E.ONs nätverksmodell i programvaran PSS/E för kraftsystemsimuleringar, med data för transmissionsnätet, regionnätet och delar av distributionsnätet inkluderat. Solcellsanläggningar med en nominell kapacitet från 32 MWp och uppåt ansluts till stationer i regionnätet, där snabba spänningsvariationer på nominella spänningsnivåer om 20/10 kV studeras och utvärderas ur kraftproducentens perspektiv. Från resultaten kan man dra slutsatsen att ingen av de genomförda studierna resulterar i spänningsvariationer som överskrider E.ONs tekniska krav på snabba spänningsvariationer i anslutningspunkten. Vidare visar resultaten från värsta-fallstudien vikten av att analysera det specifika systemet vid anslutning av solcellsanläggningar, eftersom egenskaperna hos det befintliga systemet har en inverkan på spänningsvarationerna. Tidsserieberäkningarna visar att spänningsvariationerna över en tidsperiod av ett år påverkas starkt av både energiproduktionen och lastkapaciteten i stationen, och studien med en överdimensionerad solcellsanläggning visar på möjligheten att öka den nominella kapaciteten utan att spilla stora mängder aktiv effekt. Slutligen ger studien med reaktiv effektkompensation slutsatser om att strategier i växelriktare kan vara en möjlig lösning för att utnyttja det befintliga elnät optimalt och möjliggöra en fortsatt expansion av storskaliga solcellsanläggningar i det svenska kraftsystemet.

The subject of the diploma thesis is the solution of chosen parts of the construction technology project of the 1st phase of the construction „Komplex RD Slavkov, Pod Zlatou horou“. These are 4 semi-detached houses, overall 8 family houses. The work deals with technological regulations for the superstructure including roof, study of the realization of the construction technology project, design of the main construction machines and mechanisms and control and test plan. For the whole construction is elaborated time and financial plan in two variants, namely the gradual and current method of construction, and a detailed schedule for one semi-detached house. The technical report of the building site equipment is completed with the drawings, itemized budget of the building part of the house, noise study and specialization focused on the photovoltaic system, with an alternative solution to use solar collectors. The thesis also includes a case study of construction methods focused on the gradual and current method of construction.

The thesis discuses an integration of photovoltaic power stations to electric network. The first part describes connecting conditions of small sources to distribution system, including administrative requirements, feasibility study, and requirements to the energy meters, measuring, control devices, switching devices and protection. The second part is aimed to describe problems of the photovoltaic system. Solar radiation generating and reducing of its intensity incident upon the earth surface are described in this part. The quantum of produced electric power depends on climatic conditions in the fixed area, seasons, etc. This work also discusses the types of photovoltaic cells and their actual efficiency. Inverters are further important components of the photovoltaic system. The parameters of the inverters have a great influence on the total actual efficiency of the photovoltaic system. Different methods of the photovoltaic panels’ connection with the inverters and their advantages and disadvantages are also mentioned. The supporting structure of the photovoltaic panels and eventually transformer are further important components of photovoltaic system. The work also analyze the methods of connection of the photovoltaic power station to distributive low voltage and medium voltage network, electric energy accumulation and possibilities of the sale of produced electric energy. The large number of the connected photovoltaic power stations has negative influences to electric network. The third part contains the design of a photovoltaic power plant with a capacity of 516,24 kWp on the scoped area in southern Bohemia. The project documentation for the location where the power plant is designed is also made. It contains the design of photovoltaic panels, the design of the inverters to get an optimal power load. This part also contains a calculation of the photovoltaic system losses and the design of transformer and the cable junction calculation of the distributive system. The feasibility study of the power plant connected to distributive system is also conducted. Its delivery rate will be connected to the distribution point Řípov (110/22 kV). The calculation results show us that this photovoltaic power plant can be linked to the distribution system. The final part of this paper contains an economic estimate of the photovoltaic power plant operating and the calculation of the return. An Economic return is influenced by the wide range of values that affect the total return rate. The calculation of an operating economy is made for several variants. The return rate in refer to contemporary redemption price for 2010 with no consideration for a bank loan is 7 years. If we consider the bank loan it would be 12 years. The penetrative reduction of the redemption price is expected for 2011. Calculation works with the decline of 30 %. It would extend the rate of return to 11 years without a bank loan or to 22 years with the bank loan. The bank loan is considered to cover 80 % of the investment.