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Author: | Keinänen, Mikko |
Title: | Latent heat recovery from supercooled sodium acetate trihydrate using a brush heat exchanger |
Lämmöntalteenotto alijäähtyneestä natriumasetaatti trihydraatista harjalämmönvaihtimissa | |
Publication type: | Master's thesis |
Publication year: | 2007 |
Pages: | 104 Language: eng |
Department/School: | Konetekniikan osasto |
Main subject: | Lämpötekniikka ja koneoppi (Ene-39) |
Supervisor: | Lampinen, Markku |
Instructor: | Seppälä, Ari |
OEVS: | Electronic archive copy is available via Aalto Thesis Database.
Instructions Reading digital theses in the closed network of the Aalto University Harald Herlin Learning CentreIn the closed network of Learning Centre you can read digital and digitized theses not available in the open network. The Learning Centre contact details and opening hours: https://learningcentre.aalto.fi/en/harald-herlin-learning-centre/ You can read theses on the Learning Centre customer computers, which are available on all floors.
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Location: | P1 Ark TKK 6355 | Archive |
Keywords: | heat recovery latent heat storage supercooling brush heat exchanger sodium acetate trihydrate curved pipe heat transfer lämmöntalteenotto faasimuutosvarasto alijäähtyminen harjalämmönvaihdin natriumasetaatti trihydraatti lämmönsiirto kierreputkessa |
Abstract (eng): | This study is a part of a research project developing heat storages for warming automobile combustion engines. Thermal storage is charged with engine waste heat, which is discharged in order to maintain proper engine temperature or used for preheating. The supercooling phenomenon intrigued us because of its ability to store the latent heat of phase change material (PCM) without any losses for long periods of time and release it when desired. In this work, heat recovery as supercooled liquid sodium acetate trihydrate (SAT) encounters rapid phase change in the various brush heat exchangers is studied. Laboratory experiments uncover the suitability of supercooled sodium acetate trihydrate as a latent heat storage medium by output capacities and repeatability of the freeze-thaw cycles. An effect that the degree of supercooling and coolant flow rate has on the heat recovery is also considered. Curved pipe heat transfer characteristics and optimal curvature for efficient heat transfer with adequate pressure losses was studied by minimizing the entropy generation rate in heat transfer pipe. Results revealed an exiguous relation between brush density and output capacities and heat recovery rate. For low power requirements, coarser brushes should be utilized, as the heat release rate is moderate. Crystallization experiments conducted in glass vessels compared to the ones performed in the brush heat exchangers showed a significant difference of the stability of the supercooled metastable state and the degree of supercooling. Thus, major work has to be pursued in developing stable and reliable supercooled phase change material, as spontaneous crystallization must be prevented. |
ED: | 2007-10-26 |
INSSI record number: 34811
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