Title Proračun solarnih termalnih paraboličnih žljebastih kolektora Title (english) Calculation of solar thermal parabolic trough collectors Author Vedran Horvatinec Mentor Zvonimir Glasnović (mentor)Committee member Zvonimir Glasnović (predsjednik povjerenstva)Committee member Ante Jukić (član povjerenstva)Committee member Juraj Šipušić (član povjerenstva)Granter University of Zagreb Defense date and country 2020-02-27, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Radom je prikazan proračun termalnih paraboličnih žljebastih kolektora, čije učešće u koncentratorskim sustavima danas zauzima oko 90%. Razlog njihove, tako velike primjene je najniža cijena u odnosu na druge termalne koncentratorske sustave. Uz to, ta vrsta kolektora postiže relativno visoku efikasnost pretvorbe iz solarne u toplinsku energiju (60-80%, a što ovisi o omjeru koncentracije, odnosno postignutoj temperaturi), dok učinkovitost pretvorbe u električnu energiju kod solarnih termalnih elektrana iznosi oko 14-16%. Problem paraboličnih žljebastih kolektora je da oni koriste samo direktnu komponentu solarnog zračenja i to samo kad ono prelazi intenzitet od 300 W/m^2 (što odgovara dnevnim vrijednostima energije solarnog zračenja iznad 2 kWh/m^2), dok im je najveći nedostatak da oni moraju pratiti Sunce. Proračuni polaze od termičkih gubitaka reflektora i apsorpcijske cijevi. Prikupljena solarna energija predstavlja umnožak faktora djelotvornosti za odvođenje topline, zatim dugoročnog prosjeka optičke djelotvornosti kolektora, dugoročnog prosjeka faktora iskorištenja Sunčeve energije prema Hottel-Whillierovom konceptu i prosječne dnevne vrijednosti prikupljene solarne energije. Pri tome se energija koja je prikupljena kolektorom računa kao razlika energije hemisfernog i difuznog zračenja, dok je veličina dugoročnog prosjeka faktora iskorištenja Sunčeve energije nelinearna funkcija indeksa vedrine i kritičnog omjera energija. U svrhu proračuna proizvedene toplinske energije paraboličnih žljebastih kolektora u realnim uvjetima, odabrana je lokacija Otoka Visa na kojoj godišnje vrijednosti solarnog zračenja iznose 1545 kWh/m^2. Proračunima su dobivene jedinične vrijednosti proizvedene toplinske energije od 459.57 kWh/m^2, a koja bi, uz učinkovitost pretvorbe iz toplinske u električnu energiju od 35%, mogla proizvesti 160.85 kWh/m^2 električne energije. Problem primjene termalnih paraboličnih žljebastih kolektora se ogleda u tome da u tri mjeseca (studenom, prosincu i siječnju) oni praktički ne mogu proizvoditi energiju pa bi se elektrana s tom vrstom kolektora u konkretnom slučaju morala spojiti na električnu mrežu. Međutim, ukoliko bi se solarna termalna elektrana s paraboličnim žljebastim kolektorima integrirala s reverzibilnom hidroelektranom, takav integrirani izvor energije bi mogao kontinuirano napajati sva naselja Otoka Visa tijekom cijele godine.
Abstract (english) The calculation of the parabolic trough collectors, which make 90% in current solar concentrators system is presented in this Master’s thesis. The reason of their wide application is the lowest price comparing to the other thermal concentration systems. In addition, this type of collector achieves relatively high conversion efficiency from solar into thermal energy (60-80%, what depends on concentration ratio and achieved temperature), wheras efficiency of conversion from solar to electrical energy in solar thermal power plants is approximately 14-16%. The problem of parabolic trough collectors is that only direct component of solar radiation can be used and it is only when solar radiation exceeds 300 W/m^2 intensity (corresponding to daily solar radiation above 2 kWh/m^2), whereas their biggest disadvantage is that they need track the sun. Calculations start from thermal losses of reflector and absorption tube. Collected sollar energy is calculated from the product of heat removal factor, then long-term optical collector efficiency average, long-term average utilization factor of solar energy based on Hottel–Whillier concept and average daily value of the collected solar energy. Thereby collected energy is calculated as the energy difference of hemisferic and diffuse radiation, while long-term optical collector efficiency average of solar energy is based on unlinear function of clearness index and critical energy ratio. For the purpose of calculation of produced parabolic trough collectors thermal energy in real conditions, the location of the Island of Vis was selected, with annual solar radiation values of 1545 kWh/m^2. By calculations, produced thermal energy unit values of 459.57 kWh/m^2 are obtained, and it could produce 160.85 kWh/m^2 of electrical energy, by means of 35% thermal to electric energy conversion efficiency. Thermal parabolic trough collectors problem comes from that, for the winter months time (November, December and January), they are not able to produce energy so power plant with that kind of collectors should be connected to electrical network. However, if solar thermal plant with parabolic trough collectors is integrated with pump storage hydroelectric, such integrated energy source could continuously supply all settlements on the Island of Vis, throughout the whole year.
Keywords
obnovljivi izvori energije
solarna energija
solarna termalna elektrana
parabolični žljebasti kolektor
proračuni
Keywords (english)
renewable energy sources
solar energy
solar thermal power plant
parabolic trough collector
calculations
Language croatian URN:NBN urn:nbn:hr:149:205314 Study programme Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2022-03-03 09:37:02
