Technical Brief

Initial Study on Controllable Roofing System to Tailor Building Solar Loads for Increased HVAC Efficiency

[+] Author and Article Information
Daniel M. Wolfe

Department of Electrical
and Computer Engineering,
University of Delaware,
140 Evans Hall,
Newark, DE 19716
e-mail: wolfedm@udel.edu

Keith W. Goossen

Department of Electrical
and Computer Engineering,
University of Delaware,
107 Evans Hall,
Newark, DE 19716
e-mail: goossen@udel.edu

Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING: INCLUDING WIND ENERGY AND BUILDING ENERGY CONSERVATION. Manuscript received September 3, 2014; final manuscript received April 3, 2015; published online May 19, 2015. Assoc. Editor: Jorge E. Gonzalez.

J. Sol. Energy Eng 137(4), 044503 (Aug 01, 2015) (3 pages) Paper No: SOL-14-1251; doi: 10.1115/1.4030402 History: Received September 03, 2014; Revised April 03, 2015; Online May 19, 2015

Space heating and cooling account for a significant percentage of a building's overall energy usage profile. The construction of a building's envelope is an essential component that impacts the overall heating and cooling load. For many years, flat roofs were covered with low albedo materials such as asphalt or modified bitumen, which can reach temperatures of 60 °C–80 °C during summer months. More recently, alternative technologies, such as “white roofs,” have been put forth to mitigate the problem of unwanted thermal gain. However, these traditional roofing materials and recent innovations are passive structures and only promote seasonal benefits. This paper proposes and demonstrates the concept of a controllable reflectance roofing system that can tailor solar loads to desired heating or cooling, significantly reducing overall space heating and cooling energy requirements and costs.

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Grahic Jump Location
Fig. 1

Simulated results of increasing roof albedo from 0.10 to 0.40 for seven U.S. cities [9]

Grahic Jump Location
Fig. 2

Shingle modes of operation: high albedo (top-left and top-right), high absorbance (bottom-left and bottom-right)

Grahic Jump Location
Fig. 3

Cross section of the simulated model and an illuminated shingle on the solar simulator

Grahic Jump Location
Fig. 4

Normal-to-normal transmission of power for tribead and pony bead packed shingles with interstitial mediums of air and water



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