On the cooling potential of cool roofs in cold climates: Use of cool fluorocarbon coatings to enhance the optical properties and the energy performance of industrial buildings
Section snippets
Introduction and state of the art
Extensive urbanisation has created economic, social, energy and environmental challenges for the built environment [1]. The deterioration of the urban environment and the urban heat island has become a common problem in many major cities worldwide while the temperature increase intensifies the energy demand for cooling [2], [3], [4], [5]. Implementation of urban microclimate improvement and energy efficiency strategies such as the application of cool materials has become an important priority
Materials and methods
The studied coating is a tetrafluoroethylene monomer fluorocarbon coating (FC coating) in a water-borne formula which is applied on a cement tile (7 cm × 7 cm) and on an aluminium substrate (10 cm × 10 cm). Together with the specific coating a series of other coatings are measured for comparison purposes. The coatings are:
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S1: methyl methacrylate coating.
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S2: water based elastomeric coating.
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S3: polyurethane coating.
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S4: fluorocarbon coating in a water-borne formula (FC Coating).
The characteristics of
Accelerated weathering
Accelerated ageing of all samples is performed in an accelerated ageing xenon test chamber (Q-SUN, Xe-3HS) for a 60 days period in a 24 h basis according to the specifications and requirements of ISO 11341 [32].
Xenon arc lamp test chamber tests materials for photostability by exposing them to ultraviolet, visible and infrared radiation. It produces the most realistic simulation of full spectrum sunlight using filtered xenon arc light.
With a nominal cut-on of 295 nm, the daylight filter used,
Field testing description
Following the laboratory testing, the FC coating was applied on the roof of an industrial building located in Oss, Netherlands in order to perform field testing.
The field testing measurements were performed in two phases, i.e. before (1st Phase) and after (2nd Phase) the FC coating application on the roof. The measurements performed are:
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Measurement of the roof's albedo.
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Thermal imaging of the roof on hourly basis.
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Thermal imaging of the interior spaces at 8:00, 12:00 and 16:00.
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Measurement of
The energy performance of the cool roof application
The aim of the present analysis is to provide quantitative results on the energy efficiency that can be achieved by the application of the cool material in the specific building. The building's cooling and heating loads were calculated for the 1st and 2nd phase using EnergyPlus thermal load simulation programme Version 7.1. The calculations were performed with a 15 min time step to allow the simulation algorithm to converge. The values of the albedo measurements are inserted in the model
Conclusions
In the present study the thermal and optical characteristics of a fluorocarbon cool material are measured. The cool material is applied in an industrial building with increased internal heat gains targeting to minimise the energy demand for cooling. The specific building is in Northern climatic conditions where the heating penalty of cool materials is of a great significance. The value of the roof albedo has changed from 0.3 to 0.67 after the application of the cool coating. There is an
Acknowledgments
Herewith we are acknowledging TecneXum GmbH, Essen, Germany, and Daikin Chemical Europe, Düsseldorf, Germany, for their support and to enable us to perform these studies and to publish the results.
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