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Title: Experimental validation for thermal transmittances of window shading systems with perimeter gaps

Journal Article · · Journal of Building Performance Simulation
 [1];  [1];  [1]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Virtually all residential and commercial windows in the U.S. have some form of window attachment, but few have been designed for energy savings. ISO 15099 presents a simulation framework to determine thermal performance of window attachments, but the model has not been validated for these products. This paper outlines a review and validation of the ISO 15099 centre-of-glass heat transfer correlations for perimeter gaps (top, bottom, and side) in naturally ventilated cavities through measurement and simulation. The thermal transmittance impact due to dimensional variations of these gaps is measured experimentally, simulated using computational fluid dynamics, and simulated utilizing simplified correlations from ISO 15099. Results show that the ISO 15099 correlations produce a mean error between measured and simulated heat flux of 2.5 ± 7%. These tolerances are similar to those obtained from sealed cavity comparisons and are deemed acceptable within the ISO 15099 framework.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
1456998
Journal Information:
Journal of Building Performance Simulation, Vol. 11, Issue 6; ISSN 1940-1493
Publisher:
Taylor & FrancisCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

References (13)

Two-dimensional model for the double glass naturally ventilated window journal January 2005
Thermal performance modelling of complex fenestration systems journal September 2009
Evaluation of the thermal performance indices of a ventilated double window through experimental and analytical procedures: Uw-values journal March 2014
Developing laminar free convection between vertical flat plates with asymmetric heating journal November 1972
Theoretical and experimental research on the additional thermal resistance of a built-in curtain on a glazed window journal February 2015
A study of the U-factor of a window with a cloth curtain journal April 2001
Heat Transfer by Natural Convection Across Vertical and Inclined Air Layers journal February 1982
Simulation study on an air flow window system with an integrated roll screen journal January 1997
Experimental validation and model development for thermal transmittances of porous window screens and horizontal louvred blind systems journal May 2017
Empirical Correlations for Free Convection in an Isothermal Asymmetrically Heated Vertical Channel journal February 2009
Natural convection in an enclosed vertical air layer with large horizontal temperature differences journal August 1986
Natural convection at an indoor glazing surface with different window blinds journal October 2010
Modelling and simulation of a ventilated double window journal January 2011