Study of PCM based Thermal Energy Storage for the Ventilated Window Concept
Authors
Jensen, Anne Kathrine ; Mikalainis, Mindaugas
Term
4. term
Publication year
2019
Submitted on
2019-06-10
Pages
170
Abstract
Ventilated windows have potential to reduce building energy use, but performance improvements are needed. This thesis examines whether thermal energy storage (TES) using phase change materials (PCM) encapsulated in steel can enhance a proposed ventilated window concept for passive pre-heating and pre-cooling of supply air. Two storage media—palm oil and micro-encapsulated paraffin—were characterized by differential scanning calorimetry to assess phase change behavior within the target 10–30 °C range. Controlled test-box experiments simulated winter pre-heating and summer pre-cooling, numerical models sought to replicate the controlled experiments and explore optimization options, and a facade laboratory setup under uncontrolled conditions evaluated integrated storage solutions (including paraffin-infused boards). Findings indicate that palm oil does not exhibit significant latent heat in the relevant temperature range, whereas micro-encapsulated paraffin in a steel container and paraffin-infused boards delivered similar performance, with approximately 42% storage efficiency and 37% discharge efficiency in both strategies. The results identify paraffin-based materials as promising for TES in ventilated windows and highlight opportunities for further improvement in container design, control, and operating conditions.
Ventilerede vinduer rummer potentiale for energibesparelser i bygninger, men der kræves optimering for at øge ydeevnen. Denne afhandling undersøger, om termisk energilagring (TES) med faseforandringsmateriale (PCM) i en stålindkapslet enhed kan forbedre et foreslået ventileret vindueskoncept til passiv forvarmning og forkøling af indblæsningsluft. To lagermedier – palmeolie og mikroindkapslet paraffin – blev karakteriseret med differential skanningskalorimetri for at vurdere faseændringsadfærd i det ønskede temperaturområde 10–30 °C. Yderligere blev der gennemført kontrollerede forsøg i en testboks for at simulere vinter-forvarmning og sommer-forkøling, numeriske simuleringer for at replikere de kontrollerede forsøg og identificere optimeringsmuligheder, samt forsøg i en facadeopsætning under ukontrollerede forhold med integreret lagring (herunder paraffin-inficerede plader). Resultaterne viser, at palmeolie ikke har betydelig latent varme i det relevante temperaturinterval, mens mikroindkapslet paraffin i stålkapsel og paraffin-inficerede plader leverer sammenlignelig ydeevne med ca. 42 % lagringsvirkningsgrad og 37 % afladningsvirkningsgrad i både forvarmnings- og forkølingsstrategier. Arbejdet peger dermed på paraffinbaserede materialer som lovende kandidater til TES i ventilerede vinduer, samtidig med at der identificeres forbedringsmuligheder i beholderdesign, styring og driftsbetingelser.
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