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Polyol-polymer mixture for long-term latent heat storage

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Yazdani, Maryam Roza
dc.contributor.advisor Turunen, Konsta
dc.contributor.author Annenkova, Irina
dc.date.accessioned 2020-08-24T06:57:57Z
dc.date.available 2020-08-24T06:57:57Z
dc.date.issued 2020-08-17
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/46175
dc.description.abstract In this work, novel phase change material (PCM) based on polyol-polymer mixture was developed for long-term thermal energy storage purposes, which is especially relevant for cold-climate regions, such as Nordic countries due to high heat demand in winter time. Unlike to the currently used sensible heat storages, supercooling PCMs provide large energy density in smaller volume without the need for proper insulation due to the absence of heat losses over the storage period. The overview of thermal energy storage technologies is presented in the theoretical section with the emphasis on cold-crystallization mechanism, which is based on the supercooling effect of the material and allows to significantly prolong the storage period. This thesis has been conducted under the umbrella of Heatstock Project concentrating on developing reliable long-term heat storage materials. The novel material consists of erythritol and mannitol mixture, improved by dispersing it in polyvinyl alcohol as a supporting polymer matrix. Due to the ability to vitrify and to cold-crystallize, the material is capable of storing the heat in supercooled state and controllably releasing it when the discharge is triggered by heat impulse. In the experimental section the optimal PCM composition is defined on the basis of its thermal behavior, analyzed by means of differential scanning calorimetry (DSC). The specific heat capacity measurement is performed to estimate the approximate triggering heat impulse and prove the PCM’s feasibility for industrial applications. The storage and cycling stability were confirmed by bulk storage tests of 10 g samples and 50 consecutive DSC heating-cooling cycles. The PCM also demonstrated good thermal stability within operation temperature range (up to 150 C). The results display promising perspectives of using polyol-polymer mixture as PCM for long-term thermal energy storage. The novel material demonstrates high latent heat of melting (198 J/g) and crystallization (129 J/g), as well as good cycling stability of melting and the ability to store heat up to 2 weeks at 0 C in bulk size. Moreover, the addition of PVA allows to prevent melted PCM’s leakage from container by giving it form-stability. Therefore, novel polyol-polymer mixture has a potential for further developing in terms of upscaling and increasing the storage period. en
dc.format.extent 42
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.title Polyol-polymer mixture for long-term latent heat storage en
dc.type G2 Pro gradu, diplomityö fi
dc.contributor.school Insinööritieteiden korkeakoulu fi
dc.subject.keyword long-term heat storage en
dc.subject.keyword phase change material en
dc.subject.keyword polyol-polymer mixture en
dc.subject.keyword supercooling en
dc.subject.keyword cold-crystallization en
dc.identifier.urn URN:NBN:fi:aalto-202008245114
dc.programme.major Sustainable Energy Conversion Processes fi
dc.programme.mcode ENG3069 fi
dc.type.ontasot Master's thesis en
dc.type.ontasot Diplomityö fi
dc.contributor.supervisor Santasalo-Aarnio, Annukka
dc.programme Master's Programme in Advanced Energy Solutions (AAE) fi
local.aalto.electroniconly yes
local.aalto.openaccess yes

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