Simplified and dynamic calculation method for a façade with double glazing and internal shading device
Authors
Llop Chocarro, Juan Bautista ; Lungu, Laurentiu-Stefan ; Wysocka, Izabela Ewa
Term
4. term
Publication year
2016
Submitted on
2016-06-13
Abstract
Dette speciale adresserer behovet for en enkel, dynamisk beregningsmetode til at vurdere energi- og komfortforhold i bygninger med højt glasareal, specifikt dobbeltglasfacader med indvendig solafskærmning. Med afsæt i en eksisterende 1D-model udvikles to tilgange: en SHGC-baseret model, der anvender total solenergitransmittans og en empirisk behandling af indfaldsvinkel for at beregne rum- og kavitetstemperaturer, samt en mere detaljeret model, der behandler de to ruder og gardinet hver for sig med vinkelafhængige optiske egenskaber og modelleret luftbevægelse i kaviteten, så både luft- og overfladetemperaturer (og dermed lokal termisk komfort) kan vurderes. Metoden bygger på internationale standarder (bl.a. EN 410, EN 673, EN 13363-1/-2 og ISO 15099), og to typer indvendige solgardiner undersøges. Modellerne valideres mod målinger i et fuldskala facadelaboratorium på Aalborg Universitet, og en følsomhedsanalyse identificerer centrale parametre. Resultaterne viser, at begge tilgange giver rimelige estimater af energi til opvarmning og køling, men med afvigelser relateret til sandsynligt overvurderede varmetab; rumlufttemperaturen rammes godt, mens den detaljerede model bedre rammer kavitetstemperaturer, men er mere følsom over for meget reflekterende gardiner. Den udviklede metode muliggør helårssimuleringer med variable tidsopløsninger og kan understøtte tidlig designbeslutning for glasfacader med indvendig afskærmning, om end der fortsat er behov for videre udvikling, især i behandlingen af kavitet og gardin.
This thesis addresses the need for a simple, dynamic calculation method to assess energy and comfort in highly glazed buildings, focusing on double-glazed façades with internal shading. Building on a previously developed 1D model, two approaches are proposed: an SHGC-based model that uses total solar energy transmittance and an empirical treatment of incidence-angle effects to estimate room and cavity air temperatures, and a more detailed model that treats each pane and the blind separately with angle-dependent optical properties and modeled airflow in the cavity, enabling calculation of both air and surface temperatures (and thus local thermal comfort). The method is grounded in international standards (including EN 410, EN 673, EN 13363-1/-2, and ISO 15099), and two internal shading fabrics are investigated. The models are validated against measurements in a full-scale façade test facility at Aalborg University, and a sensitivity analysis identifies key influencing parameters. Results indicate that both approaches provide reasonable estimates of heating and cooling energy, with deviations likely linked to overestimated heat losses; room air temperatures match well, the detailed model better captures cavity temperatures, but it is more sensitive to highly reflective blinds. The developed method supports whole-year simulations at various time steps and can inform early design decisions for glazing façades with internal shading, while highlighting the need for further development, particularly in the treatment of the cavity and the blind.
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