Thermal performance modelling of complex fenestration systems

Complex fenestration systems (CFS) have become standard elements in facade design of high performance buildings. They include, for example, shading devices to control illumination, solar heat gains, glare and view-out, and photovoltaic elements imbedded in glazing layers to produce electrical energy on site. However, current methodologies to evaluate the thermal performance of CFS are limited to few products and types. This article develops a general methodology to compute the thermal performance of CFS. The methodology assumes each system layer as porous with calculated effective radiation and thermal properties. A new thermal penetration length model was developed to account for the effects of porous layers on the convective film coefficients of adjacent gas spaces, and applied to various types of shading devices. This methodology is validated using the available measurement and computational fluid dynamics (CFD) simulation results for the U-factor of double-glazed windows with between-pane and internal blinds.

[1]  John L. Wright Calculating Center-Glass Performance Indices of Glazing Systems with Shading Devices , 2008 .

[2]  David Naylor,et al.  A simplified method for modelling the effect of blinds on window thermal performance , 2006 .

[3]  David Naylor,et al.  Numerical Study of Convective and Radiative Heat Transfer from a Window Glazing with a Venetian Blind , 2001 .

[4]  D. Naylor,et al.  Experimental Study of Natural Convection in a Window with a Between-Panes Venetian Blind , 2007 .

[5]  Antonio F. Miguel Airflow through porous screens: From theory to practical considerations , 1998 .

[6]  David Naylor,et al.  Heat Transfer From an Isothermal Vertical Surface With Adjacent Heated Horizontal Louvers: Validation , 2002 .

[7]  E. A. Farber,et al.  Theoretical analysis of solar heat gain through insulating glass with inside shading , 1963 .

[8]  David Naylor,et al.  Heat Transfer From an Isothermal Vertical Surface With Adjacent Heated Horizontal Louvers: Numerical Analysis , 2002 .

[9]  Iso Tc,et al.  Thermal Performance of Windows, Doors and Shading Devices — Detailed Calculations , 2000 .

[10]  M. Collins,et al.  Validation of Solar/Optical Models for Louvered Shades Using a Broad Area Illumination Integrating Sphere , 1995 .

[11]  Monika Woloszyn,et al.  Three-dimensional simulation with a CFD tool of the airflow phenomena in single floor double-skin facade equipped with a venetian blind , 2005 .

[12]  X. Fang,et al.  A Study of the U-Factor of the Window with a High-Reflectivity Venetian Blind , 2000 .

[13]  John L. Wright,et al.  Determining Off-Normal Solar Optical Properties of Drapery Fabrics , 2009 .

[14]  H.A.L. van Dijk,et al.  Modelling the optical and thermal properties of complex glazing: overview of recent developments , 2001 .

[15]  A. Schaelin,et al.  Airflow patterns and thermal behavior of mechanically ventilated glass double façades , 2004 .

[16]  Chanvit Chantrasrisalai,et al.  An In Situ Experimental Method for the Development and Validation of Slat-Type Blind Models in Cooling Load Calculations , 2006 .

[17]  O. G. Martynenko,et al.  Convective heat transfer , 1989 .

[18]  John L. Wright,et al.  Methods for Calculating the Effective Solar-Optical Properties of a Venetian Blind Layer , 2005 .

[19]  M. Collins Convective heat transfer coefficients from an internal window surface and adjacent sunlit Venetian blind , 2004 .

[20]  P. Oosthuizen,et al.  Experimental Study of Free Convection at an Indoor Glazing Surface with a Venetian Blind , 1998 .

[21]  Adrian Bejan,et al.  Natural Convection in a Vertical Enclosure With Internal Permeable Screen , 1991 .

[22]  Hidayat Shahid,et al.  Energy performance assessment of a window with a horizontal Venetian blind , 2005 .

[23]  L. Burmeister Convective heat transfer , 1983 .

[24]  J. Rosenfeld,et al.  Optical and thermal performance of glazing with integral venetian blinds , 2001 .

[25]  S. Corgnati,et al.  Experimental assessment of the performance of an active transparent façade during actual operating conditions , 2007 .

[26]  Xiande Fang A study of the U-factor of a window with a cloth curtain , 2001 .

[27]  John L. Wright,et al.  Thermal Resistance of a Window with an Enclosed Venetian Blind: A Simplified Model , 2008 .

[28]  D. Naylor,et al.  Free convective heat transfer in an enclosure with an internal louvered blind , 2008 .

[29]  John L. Wright,et al.  Determining Off-Normal Solar Optical Properties of Roller Blinds , 2009 .

[30]  John L. Wright,et al.  Calculating center-glass performance indices of windows with a diathermanous layer , 2006 .

[31]  John L. Wright,et al.  Thermal resistance of a window with an enclosed venetian blind : Guarded heater plate measurements , 2006 .

[32]  D. Naylor,et al.  EVALUATION OF AN APPROXIMATE METHOD FOR PREDICTING THE U VALUE OF A WINDOW WITH A BETWEEN-PANES BLIND , 2005 .

[33]  Henk Oversloot,et al.  WIS, the European tool to calculate thermal and solar properties of windows and window components , 2003 .