Thermal VI Conference: Fenestration Research Results The Sixth Thermal Performance of the Exterior Envelope of Buildings Conference was held in Clearwater Beach, Florida on December 4-8, 1995. The conference focused on the building science of envelope performance from research to practice and application.
Thermal VI was jointly sponsored by the U.S. Department of Energy (DOE), American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE), Oak Ridge National Laboratory (ORNL), and the Building Environment and Thermal Envelope Council (BETEC).
The full proceedings (792 pages) is available from the ASHRAE, Inc., 1791 Tullie Circle, N.E., Atlanta, GA 30329, for $111.00 plus $3.00 shipping charge. Listed below are paper titles, authors and edited abstracts for papers that directly addressed fenestration technology and performance.
A Wall and Edge Guarded Hot Box for Fenestration Testing. S.D. Gatland II and R.G. Miller. Center for Applied Engineering, Inc., (813) 578-4332, Fax (813) 576-0318; W.P. Goss, University of Massachusetts, Mechanical Engineering Department, Amherst; R.L. Baumgardner, Rollin Inc., Stroudsburg, PA; and R.G. Williams, Division of Quantum Metrology, National Physical Laboratory, Teddington, U.K.
Abstract: A unique guarded hot box that incorporates several new design concepts from guarded hot plates, namely wall and edge guards, is described in detail. This new approach to the guarded hot box operates with improved temperature and power control.
The test facility is rotatable, with the ability to provide upward or horizontal heat flow. Both the climatic and metering chambers provide variable air velocities parallel to the specimen surface.
Active Computational Support for Concurrent Building Envelope and Lighting System Design. Ardeshir Mahdavi, Liana Berberidou Kallivoka, and Zhonghu Li. Carnegie Mellon University, Department of Architecture, (412) 268-6389, Fax (412) 268-6129.
Abstract: This paper introduces an active computational tool to generate and comparatively evaluate integrated building envelope and interior lighting system designs. The /"generate-and-test/" method is adopted to realize this active system feature. The tool is intended to facilitate the comparative evaluation of the generated envelope and room lighting schemes in view of daylight utilization potential, visual performance criteria, and energy consumption levels.
Advancements in Thermal and Optical Simulations of Fenestration Systems: The Development of WINDOW 5. Finlayson E., Arasteh A., Rubin M., Sadlier J., Sullivan R., Lawrence Berkeley National Laboratory, (510) 486-6844, Fax (510) 486-4089; Huizenga C., Center for Environmental Design Research, University of California, Berkeley; Curcija D., Department of Mechanical Engineering, University of Massachusetts, Amherst; and Beall M., Scientific Computation Research Center, Rensselaer Polytechnic Institute, Troy, New York.
Abstract: WINDOW 5 scheduled for release in 1996 is the latest version of a tool now widely used by industry, the NFRC, and researchers, to design and rate windows. It will provide increased accuracy, a flexible and state-of-the-art user interface, and the capabilities to handle more product types.
WINDOW 5 includes THERM, a new 2D finite element thermal model with the capabilities to define and model the thermal performance of frames/dividers and their associated edge effects.
WINDOW 5 also will include a built-in version of RESFEN that calculates the orientation-dependent annual energy impacts of a given window in a typical residence in various U.S. climates, an improved angular/spectral model for coated and uncoated glazings, the ability to analyze the optical properties of nonhomogeneous layers, and the ability to model the effects of laminated glazing layers.
An Assessment of Interlaboratory Repeatability in Fenestration Energy Ratings--Part 1: Interlaboratory Comparison of Simulation Results. R. Christopher Mathis and Daniel J. Wise. National Fenestration Rating Council, (301) 589-6372, Fax (301) 588-0854.
Abstract: This paper presents the results from the first interlaboratory comparison (round-robin) of fenestration thermal transmission ratings (U-factors) acquired in accordance with NFRC 100-91 SM. Procedure for Determining Fenestration Product Thermal Properties. The round-robin involved nine thermal testing laboratories and 18 certified simulators from 14 simulation laboratories. Each simulation laboratory used the same computer tools to calculate total product U-factor, center-of-glass U-factor, frame and edge-of-glass U-factor, surface temperatures, and other required information. This paper presents only the results from the simulation laboratory round-robin.
An Assessment of Interlaboratory Repeatability in Fenestration Energy Ratings--Part 2: Interlaboratory Comparison of Test Results. Daniel J. Wise and R. Christopher Mathis. National Fenestration Rating Council, (301) 589-6372, Fax (301) 588-0854.
Abstract: This companion paper to Part 1 above, presents the results from the test laboratory round robin portion of the first interlaboratory comparison of fenestration thermal transmission ratings (U-factors) acquired in accordance with NFRC 100-91 SM. The results of the round-robin testing show fairly good agreement among laboratories for the window specimen.
Edge Conduction in Vacuum Glazing. Simko T. and Collins R.E., University of Sydney, Beck F.A,. and Arasteh D. Lawrence Berkeley National Laboratory, (510) 486-6844, Fax (510) 486-4089. (See Fenestration R&D, Fall 1996, p. 6.)
Abstract: Vacuum glazing achieves very low conductance by using an internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions.
Issues Associated with the Use of Infrared Thermography for Experimental Testing of Insulated Systems. Griffith B., Beck F., Arasteh D., and Turler D. Lawrence Berkeley National Laboratory, (510) 486-6844, Fax (510) 486-4089. (See Fenestration R&D, No.1, p. 8.)
Abstract: This paper discusses the accuracy of using infrared scanning radiometers to generate temperature maps of building envelope components under steady-state, controlled laboratory conditions. Infrared imaging, with a reference emitter technique, is being used to create a database of temperature maps for a range of window systems, varying in physical complexity, material properties, and thermal performance. The data base is to be distributed to developers of fenestration heat transfer simulation programs to help validate their models.
Measured Performance of Selective Glazings. Klems J.H., Yazdanian M., and Kelley G.O. Lawrence Berkeley National Laboratory, (510) 486-5564, Fax (510) 486-4089.
Abstract: Measurements of the net heat flow through four selective glazings in comparison with clear double glazing under late summer outdoor conditions are presented. The solar heat gain coefficient (SHGC) for each glazing is extracted from the data and shown to be angle dependent. Good agreement is found between measured properties and calculations with WINDOW 4.1.
New Correlations for Convective Heat Transfer Coefficient on Indoor Fenestration Surfaces- Compilation of More Recent Work. Dragan Curcija and William P. Goss, Mechanical Engineering Department, University of Massachusetts, (413) 545-2251, Fax (413) 545-1027.
Abstract: Recommendations for indoor fenestration surface natural convection heat transfer coefficients are given as a function of temperature difference, fenestration surface length, and inclination angle from horizontal. The angles of inclination cover both /"winter/" (surface heated from below) and /"summer/" (surface heated from above) conditions. The impact of the new set of correlations is studied for several typical fenestration system configurations and compared to heat transfer results using the old correlations.
New Tools for the Analysis and Design of Building Envelopes. Papamichael K., Winkelmann F., and Selkowitz S. Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, (510) 486-6854, Fax (510) 486- 4089.
Abstract: This paper describes the integrated development of PowerDOE, a new version of the DOE-2 building energy analysis program with enhanced calculation capabilities and a new graphical user interface, and the Building Design Advisor (BDA), a multimedia-based design tool that assists building designers with the concurrent consideration of multiple design solutions with respect to multiple design criteria early in schematic design. Each of these tools allows faster and more accurate analysis of the thermal and daylighting impacts of fenestration options.
Rating the Thermal Performance of Swinging Doors: The Canadian Experience. Stephen Carpenter, Enermodal Engineering Ltd., (519) 884-6421, Fax (519) 884-0103; and Roger Henry, CANMET, Natural Resources Canada.
Abstract: This paper discusses the recent development of the Canadian standard for rating the thermal performance of swinging doors. This standard (CSA A453) defines the methodology for determining the U-factor, solar heat gain coefficient and annual energy performance (energy rating, or ER). The door standard defines the products to be evaluated and the computer simulation and physical testing procedures to determine the performance parameters.
Reducing Residential Cooling Requirements Through the Use of Electrochromic Windows. Sullivan R., Rubin M., and Selkowitz S.Lawrence Berkeley National Laboratory, (510) 486-6843, Fax (510) 486-4089.
Abstract: This study investigates the energy performance of electrochromic windows in a proto-typical residential building under a variety of state switching control strategies. The DOE-2.1E energy simulation program was used to analyze the annual cooling energy and peak demand as a function of glazing type, size, and electrochromic control strategy.
An electrochromic material with a high reflectance in the colored state provides the best performance for all control strategies. The space-cooling load-switching strategy provides the best performance for all the electrochromic materials. The comparative performance of clear low-E, tinted low-E, and overhangs are compared to electrochromic.
The Glass Roof: Sloped Glazing Need Not Leak. Chris B. Makepeach and John O'Connor, Alberta Public Works, (403) 427- 7667, Fax (403) 422-9673. Abstract: This paper reviews and summarizes results of investigations of more than 100 leaking sloped aluminum and glass roof installations. Sloped glazing designs that are based on sole reliance of the exterior seals to provide a single line of defense to water entry have repeatedly proved to be a flawed approach. Designs where the water-tightness seals are placed in a protected location, with minimal contact with water and where water is controlled and redirected to the exterior through the design of the framing, have provided watertight installations.
Thermal Performance of a Hybrid Double-Envelope Building Model. Emad M. Afifi, The Savannah College of Art and Design, (912) 238-2409, Fax (912) 238-2436.
Abstract: This paper introduces a conceptual building model that integrates passive and mechanical environmental control systems. The performance of three double envelope variations of the proposed model is compared with two variations of a single-envelope model. Hour-by-hour simulations for the Phoenix summer and winter design days are performed for the five models and results analyzed and presented.