Global ETD Search

1	PVT-panelernas plats i samhället : En vidareutveckling av Evertechs ETX-paneler Åslund, David January 2017 (has links) Abstract To prevent that the climate influences reaches critical and irreversible levels in the near future, a change in our energy consumption and our energy sources is required. It will be a combination of multiple system solutions and several types of renewable sources, both at a personal and national levels. Every hour, the sun shines at the earth with the same amount that the world's population needs in a year. It is clearly a small part of this that we could use, but it is easy to see the potential. Evertech is a company in Umeå, whose strategy is to develop products to extract and recycle heat energy from the solar renewable resource. The company has several products and all are based on a heat exchange panel. Together with the company the possibility of combining a solar module with Evertech's solar panel was tested for a hybrid to get better effect on the solar cell by cooling. Hybrids are also called PVT-modules (photovoltaic thermal). A system setup was made with a simple prototype to measure surface temperature and power difference when the solar cell was cooled by the heat exchanger absorber. The measurement study showed an increased effect of 8 % on average and a maximum of 15 %. At the time of maximum, a surface temperature difference between the solar cell and the hybrid was determined to 20°C while the average was at 15°C. A temperature gradient at the cooled module was detected, which inhibited the power increase. This indicates that a future product would have the ability to obtain higher values. By combining the solar hybrid with a geothermal heating system, one could secure both the own heat supply and the electricity supply and at the same time have the possibility of recharge the mountain. This and how the systems can benefit from each other were studied in the simulation program Polysun. The primary goal of using a hybrid system is to create as high efficiency as possible on the solar cells and to improve the SPF value of the heat pump by allowing the heat carrier to circulate through the hybrids. The difference between the SPF-value of a hybrid system in conjunction with a geothermal system was 4.2 against the geothermal system 2.7. To cover up the increased electricity consumption that the circulation meant and the heat losses against a solar collector system did not become a problem. The results of the simulations and the economic study show that a PVT-panel built on Evertech's ETX-panel together with geothermal heat has equally good conditions for managing as solar cells or traditional solar collectors. The repayment period for a PVT module was 13,8 years for a 20 % solvency payment. For a solar cell plant of the same size it became 14,5 years. The PVT had the best return on investment of 1,2 % and an annual gain of 2000 Swedish kronor of the compared systems. Solceller hybrid pvt-panel bergväme Energy Engineering Energiteknik
2	Performance Evaluation of a Photovoltaic/Thermal (PVT) Collector with Numerical Modelling Ebrahim, Mila January 2021 (has links) In Photovoltaic/Thermal (PVT) technology, both PV and solar thermal technology are integrated in the same module for simultaneous electricity and heat production. Research has shown that there are multiple benefits from integrating PVT collectors with a ground source heat pump (GSHP) system, since it allows for seasonal storage of thermal energy over the year. Furthermore, it leads to reduced operating temperatures for the PVT collectors which can increase efficiency and lifetime. The aim of this study is to present the electric and thermal performance of a PVT collector developed by Solhybrid i Småland AB, for different environmental and fluid inlet conditions that can occur when PVT collectors are connected to a GSHP system. Furthermore, the performance of this PVT design is evaluated with ASHRAE (Standard 93-2003), to allow for comparison with other PVT collector designs, with values on the overall heat loss coefficient (UL) and heat removal factor (FR). The modelling tool used for the study is the software COMSOL Multiphysics, which uses the finite element method to solve the partial differential equations in heat transfer and fluid flow problems. Based on the performance curves, the thermal and electrical efficiency of the collector is approximately 48.0-53.4% and 19.0-19.2% respectively at a reduced temperature of zero and irradiance levels of 800-1000 W/m2 for the mass flow rate of 0.026 kg/sm2 which was determined as most suitable to increase thermal performance. Furthermore, these results resulted in a heat removal factor (FR) and overall heat loss coefficient (UL) of 0.56-0.62 and 53.4-53.5 W/m2 K respectively. The results on the performance of the PVT collector in different weather conditions shows that the inlet water temperature can significantly affect operating time and the amount of thermal energy that can be extracted during the year, especially if the collector operates in a colder climate like Sweden. To assess the accuracy of the created model, future work includes experimental testing of the studied PVT collector. / En panel med kombinerad teknik av både solceller och termisk solfångare (PVT) kan producera både elektricitet och värme samtidigt. Forskning har visat att det kan finnas flera fördelar med att integrera PVT-paneler med ett bergvärmesystem, eftersom det mjliggör lagring av termisk energi över året. Dessutom leder ett sådant system till lägre drifttemperaturer som kan öka PVT-panelens effektivitet och livslängd. Syftet med studien är att presentera den elektriska och termiska prestandan av en PVT-panel utvecklat av Solhybrid i Småland AB för olika driftförhållanden som kan uppstå på grund av olika väderförhållanden och inlopps-temperaturer när panelerna är kopplade till ett bergvärmesystem. Vidare utvärderas prestandan för denna panel med ASHRAEmetoden (standard 93-2003), för att möjliggöra jämförelse med andra PVT-paneler. Modelleringsverktyget som använts i studien är mjukvaran COMSOL Multiphysics, som använder finita elementmetoden för att lösa partiella differentialekvationer i värmeöverförings-och flödesproblem. Baserat på prestandakurvorna som presenteras i resultatet, är den termiska och elektriska verkningsgraden approximativt 48.0-53.4% respektive 19.0-19.2% för en reducerad temperatur med värdet noll, en solstrålning mellan 800-1000 W/m2, för en massflödeshastighet på 0.026 kg/sm2 som beslutades som den mest lämpliga för att öka den termiska prestandan. Resultaten resulterade i en värmeavledningsfaktor (FR) och total värmeförlustkoefficient (UL) på 0.56-0.62 respektive 53.4-53.5 W/m2 K. Resultaten på PVT-panelens prestanda under olika väderförhållanden visar att vattnets inloppstemperatur kan påverka drifttiden och mängden termisk energi som kan extraheras under året avsevärt, speciellt i nordiskt klimat. För att bedöma korrektheten i resultaten och den skapade modellen rekommenderas experimentell testning av den studerade PVT-panelen. Solar energy Renewable energy Photovoltaic/thermal collector PV/Thermal PVT Collector Performance Numerical modelling COMSOL Multiphysics Ground Source Heat Pump Solenergi Förnybar energi kominerad solcell/solfångare PVT panel Prestanda Numerisk modellering COMSOL Multiphysics Bergvärme Engineering and Technology Teknik och teknologier
3	Analysis of a novel thermoelectric generator in the built environment Lozano, Adolfo 05 October 2011 (has links) This study centered on a novel thermoelectric generator (TEG) integrated into the built environment. Designed by Watts Thermoelectric LLC, the TEG is essentially a novel assembly of thermoelectric modules whose required temperature differential is supplied by hot and cold streams of water flowing through the TEG. Per its recommended operating conditions, the TEG nominally generates 83 Watts of electrical power. In its default configuration in the built environment, solar-thermal energy serves as the TEG’s hot stream source and geothermal energy serves as its cold stream source. Two systems-level, thermodynamic analyses were performed, which were based on the TEG’s upcoming characterization testing, scheduled to occur later in 2011 in Detroit, Michigan. The first analysis considered the TEG coupled with a solar collector system. A numerical model of the coupled system was constructed in order to estimate the system’s annual energetic performance. It was determined numerically that over the course of a sample year, the solar collector system could deliver 39.73 megawatt-hours (MWh) of thermal energy to the TEG. The TEG converted that thermal energy into a net of 266.5 kilowatt-hours of electricity in that year. The second analysis focused on the TEG itself during operation with the purpose of providing a preliminary thermodynamic characterization of the TEG. Using experimental data, this analysis found the TEG’s operating efficiency to be 1.72%. Next, the annual emissions that would be avoided by implementing the zero-emission TEG were considered. The emission factor of Michigan’s electric grid, RFCM, was calculated to be 0.830 tons of carbon dioxide-equivalent (CO2e) per MWh, and with the TEG’s annual energy output, it was concluded that 0.221 tons CO2e would be avoided each year with the TEG. It is important to note that the TEG can be linearly scaled up by including additional modules. Thus, these benefits can be multiplied through the incorporation of more TEG units. Finally, the levelized cost of electricity (LCOE) of the TEG integrated into the built environment with the solar-thermal hot source and passive ground-based cold source was considered. The LCOE of the system was estimated to be approximately $8,404/MWh, which is substantially greater than current generation technologies. Note that this calculation was based on one particular configuration with a particular and narrow set of assumptions, and is not intended to be a general conclusion about TEG systems overall. It was concluded that while solar-thermal energy systems can sustain the TEG, they are capital-intensive and therefore not economically suitable for the TEG given the assumptions of this analysis. In the end, because of the large costs associated with the solar-thermal system, waste heat recovery is proposed as a potentially more cost-effective provider of the TEG’s hot stream source. / text Thermoelectric generator TEG Novel thermoelectric generator Thermoelectrics Thermoelectric effect Thermoelectric modules Thermoelectric device Patent application Hot stream source Cold stream source EIA EERE Systems-level analysis Energy balance Control volume analysis Thermodynamic analysis Insolation data Insolation incident on a panel Incident insolation Extraterrestrial insolation NREL Ambient temperature data NOAA Renewable energy sources Energy generation technology Electricity generation technology Thermal energy Coupled system Emissions Greenhouse gas GHG Emissions analysis Zero-emission Emissions avoided Emission factor EF Reliability First Corporation RFC Built environment Integrated into the built environment Solar-thermal energy Solar collector system Photovoltaic thermal PVT panel Thermal storage tank Geothermal energy Geothermal heat pump GHP Ground source heat pump GSHP Numerical analysis Numerical model MATLAB Finite-difference Euler explicit Electric grid Annual energetic performance Annual electricity generation Operating efficiency System efficiency Thermodynamic characterization Economic analysis Levelized cost of energy LCOE Waste heat recovery Carbon dioxide equivalent CO2e Capital costs Installed costs Operating and maintenance costs

1

Page generated in 0.0432 seconds