Feasibility of double electrochemical flow cell for high current density conversion of heat to electricity

master's thesis

• Title (croatian): Izvodljivost dvostruko-protočne elektrokemijske ćelije za pretvorbu topline u električnu energiju kod visokih gustoća struje
• Author: Marko Plazanić
• Mentor: Zoran Mandić (mentor)
• Committee member: Zoran Mandić (predsjednik povjerenstva)
• Committee member: Marko Rogošić (član povjerenstva)
• Committee member: Domagoj Vrsaljko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2017-09-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Analysis, Synthesis and Management of Chemical Processes

Abstract

Feasibility of a double electrochemical flow cell for conversion of heat to electricity has been examined, i.e. the research question was if this system could be used as a heat engine. Redox species have temperature dependent redox potentials, and this dependence is different for different redox species. In theory if one has two different electrochemical cells at two different temperatures, with same redox species on the positive and the negative side, there should be a difference in potentials between two cells from which one could extract current and thus power that can be used for work. In this sense, two cell electrochemical heat engine has been constructed. In order to assess which redox pairs would be the most suitable for the heat engine, temperature dependent redox potentials, i.e. Seebeck coefficients, of different redox pairs were measured by cyclic voltammetry (CV). Basic measurements regarding batteries thermodynamics and its kinetics were conducted. Various sets of temperature differences (ΔT) and states-of-charge (SOC) values on the characteristics of two cell electrochemical heat engine were examined with battery tester. Measurements at open circuit voltages (OCVs) were conducted and polarisation curves were determined. Current densities of 2 mA/cm^2 were achieved through conversion of heat to electricity and the measurements indicate electrochemical heat engine is feasible, however, it is necessary to further optimize the setup and the measurement procedure.

Abstract (croatian)

Ispitana je izvedivost dvostrukog elektrokemijskog protočnog članka za pretvorbu toplinske u električnu energiju, odnosno da li se mogu upotrijebiti kao toplinski motor. U ovom radu se pokušava iskoristiti svojstvo redoks tvari gdje se potencijal neke redoks aktivne tvari mijenja drukčije s temperaturom. U teoriji, ako dva članka s istim redoks parovima rade na različitim temperaturama, zbog toga što im potencijal različito ovisi o temperaturi, generira se razlika potencijala iz koje se može izvući struja i prema tome snaga koje se može pretvoriti u rad. U tom smislu, konstruiran je toplinski motor s dvostruko-protočnim elektrokemijskim člancima. Kako bi se procijenili najprikladniji redoks parovi za toplinski motor, temperaturni koeficijenti, odnosno Seebeck koeficijenti, različitih redoks parova su određivani metodom cikličke voltametrije (CV). Provedena su osnovna mjerenja kako bi se odredile termodinamičke i kinetičke karakteristike ispitivanih protočnih članaka, tj. toplinskog motora Ispitan je utjecaj različitih vrijednosti razlika temperatura (ΔT) i stupnja napunjenosti (states-of-charge (SOC)) na karakteristike pretvornika s dvostruko-protočnim elektrokemijskim ćelijama. Provedena su mjerenja na potencijalu otvorenog kruga (OCV) te su određivane polarizacijske krivulje. Ostvarene su gustoće struje od 2 mA/cm^2 kroz pretvorbu toplinske u električnu energiju, te mjerenja ukazuju da je koncept izvediv uz prethodnu optimizaciju članaka i bolje razumijevanje parametara koji utječu na razliku potencijala.

• Keywords: flow cell; heat engine; Seebeck coefficient; CV; SOC; polarisation curve; current density
• Keywords (croatian): elektrokemijski protočni članak; toplinski motor; Seebeck koeficijent; CV; SOC; polarizacijska krivulja; gustoće struje
• Language: english
• URN:NBN: urn:nbn:hr:149:687784
• Study programme: Title: Chemical Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-04-28 09:51:03