Thermal analysis of triple and quadruple windows using partitioning radiant energy veils™ with different physical and optical properties. (1st November 2018)

• Record Type: Journal Article
• Authors: Sadooghi, Parham; Kherani, Nazir P.
• Is Part Of: Solar energy. Volume 174(2018)
• Page Start: 1163
• Page End: 1168
• Publication Date: 2018-11-01
• Subjects: Window -- Radiation -- Partitioning radiant energy veil -- Modeling -- Thermal transmittance -- Thermal resistance; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2018.07.034
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: New methodology is used to solve for center glass U-value of multi-pane window system. Wide range of optical properties, cavity widths, and glass pane thicknesses are investigated. Calculations are presented for 3 and 4 pane systems with three different fill gases. Lower U-values (higher thermal resistance) with air fill is possible through optimal design. Amenable to switchable glazing systems to meet desired thermal and visual comfort. Abstract: One of the key performance parameters for any energy efficient window product is the center of glass U-value or thermal transmittance. This paper presents a new methodology to compute the thermal performance of fenestration systems incorporating partitioning radiant energy veils™ between two panes of a window. A conduction heat transfer model is used for glazing layers coupled with radiation and convection models at the layer boundary surfaces. Partitioning radiant energy veils™ are treated as individual layers with effective radiative properties. The effect of a wide range of optical properties, pane thicknesses, pane distances and different gas fill types on thermal transmittance of the window are considered. The novel use of partitioning radiant energy veils™, having application specific properties, between two panes of a window allows to customize the thermal performance of a triple or quadruple window. It is shown that using one or two internal partitioning layers, with appropriate pane/inter-layer distances and high spectrally reflective metallo-dielectric coated layers, results in highly enhanced U-Values.