Načrtovanje in analiza sistema za izkoriščanje odpadne toplote transformatorjev

Judež, Sara (author), Blažič, Boštjan (mentor)

Magistrska naloga obravnava problem odpadne toplote energetskih transformatorjev, ki je posledica generiranih izgub med njihovim obratovanjem in se neizkoriščena sprošča v okolico. Odpadno toploto je možno koristno uporabiti preko ustrezno načrtovanega sistema, kjer osnovno funkcijo opravlja izmenjevalec toplote, ki skrbi za prenos toplote olja na ogrevalni medij objektov, tj. voda. Osrednji del magistrske naloge predstavlja izračun generiranega toplotnega potenciala na transformatorjih RTP Škofja Loka na podlagi nazivnih podatkov in realnih podatkov o obremenitvah v obdobju enega leta. Količina toplote, ki jo lahko v ta namen izkoristimo, je v glavnem odvisna od obremenitve transformatorja, njegove konstrukcije in temperature okolice. Vendar pa vseh generiranih izgub ne moremo izkoristiti, saj se del teh v obliki toplote preko procesov konvekcije in radiacije sprošča v okolico preko transformatorskega kotla, pri čemer konvekcija predstavlja pretežen del. Prikazani izračuni temeljijo na predpostavki, da bi lahko na transformatorjih izkoristili vso generirano odpadno toploto, kar pomeni, da bi moral sistem za izkoriščanje odpadne toplote delovati kot primarni hladilni sistem transformatorja. Na podlagi slednjih podatkov je tako narejena analiza o generiranem toplotnem potencialu skozi leto, v obdobju dneva in celotne kurilne sezone, ko so potrebe po toploti za namene ogrevanja objektov največje. V nadaljevanju naloge je opisano načrtovanje sistema za izkoriščanje odpadne toplote iz transformatorjev in s tem njegove prednosti in slabosti. Predstavljen je tudi realiziran sistem za izrabo odpadne toplote na RTP Škofja Loka, ki je šel uspešno v obratovanje v začetku leta 2023. Implementiran sistem ni dimenzioniran za odvajanje nazivih izgub, zato deluje zgolj kot dodatni hladilni sistem, zaradi česar je izkoristek samega sistema kot tudi prihranek manjši kot v izvedenih izračunih

• Language: Slovenian
• Keywords: energetski transformatorji, izgube transformatorjev, toplotna moč transformatorja, konvekcija, radiacija, toplotni izmenjevalci, sistem za izkoriščanje odpadne toplote, ogrevanje objektov
• Work type: Master's thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2023
• PID: 20.500.12556/RUL-147017
• COBISS.SI-ID: 156785411
• Publication date in RUL: 20.06.2023

Secondary language

• Language: English
• Title: Planning and analysis of a system for utilizing waste heat of transformers

Abstract

The master's thesis addresses the issue of waste heat emanating from power transformers, which arises from the losses generated during transformers operation and is released unused into the surrounding environment. This waste heat can be effectively utilized through a properly designed heat recovery system, with the heat exchanger serving as its fundamental component, responsible for transferring the heat from the transformer oil to the heating medium of the facilities, namely water. The crux of the master's thesis revolves around calculations of the thermal potential, generated by the transformers on RTP Škofja Loka, based on both nominal and actual load data spanning a year. The quantity of heat that can be exploited for this purpose predominantly hinges upon the transformer's load, construction, and ambient temperature. Nonetheless, not all of the transformer's generated losses can be effectively utilized, as a portion of these losses dissipates into the environment in the form of heat through transformer’s tank by convection and radiation processes, with convection being the predominant mechanism. The calculations and results presented in the thesis are based on the assumption that all the waste heat generated by the transformers could be utilized, meaning that the waste heat recovery system would have to function as the primary cooling system for the transformer. Based on this data, a comprehensive analysis is conducted regarding the thermal potential generated throughout the year, during the day and during heating season when the heat demand for building heating purposes is at its peak. The subsequent section of the thesis describes the design of the waste heat recovery system from the transformers, along with its advantages and disadvantages. The implemented waste heat recovery system at the RTP Škofja Loka, which commenced operation successfully in early 2023, is also presented. However, the implemented system is not dimensioned to handle the nominal losses; therefore, it functions merely as an additional cooling system, resulting in lower efficiency and savings, compared to the calculations performed.

• Keywords: power transformers, transformers losses, thermal power of transformers, convection, radiation, heat exchangers, heat recovery system, heating of buildings