Potential energy savings from cool roofs in Spain and Andalusia

Boixo, Sergio; Diaz-Vicente, Marian; Colmenar, A.; Castro, Manuel

doi:10.1016/j.energy.2011.11.009

Cited by 95 publications

(46 citation statements)

References 22 publications

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“…roof shading or albedo, achieve a greater decrease in indoor discomfort hours than thermal protection measures such as decreasing the roof's U-value. As explained by Boixo and his research colleagues, the three main properties of a roof surface that affect heat gain and energy flux are solar reflectance and thermal insulation [9]. In the domed roof cases, increasing the albedo of the roof surface leads to heat loss through the roof of 520 kW h, and an average indoor temperature in the month of August of 30.…”

Section: The Effect Of Materials Variables On Heat Gainmentioning

confidence: 99%

“…Using cool roofs with good roof thermal properties during the initial design and construction of the building, or when retrofitting, are usually more cost effective on both the building and urban level, this can save a considerable amount of the energy that is consumed in cooling [7,9,11]. Unfortunately, Egyptian building regulations do not make it mandatory to install cool roofs despite this often being the least expensive option to achieve the required energy performance.…”

Section: Introductionmentioning

confidence: 99%

“…Cool roofs are one of the inexpensive passive strategies that are easy to install, reduce heat gain and improve indoor thermal comfort in hot climates [9,10]. Using cool roofs with good roof thermal properties during the initial design and construction of the building, or when retrofitting, are usually more cost effective on both the building and urban level, this can save a considerable amount of the energy that is consumed in cooling [7,9,11].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings

Dabaieh

Wanas

Amer³

et al. 2015

Energy and Buildings

145

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a b s t r a c tIn hot dry climates, it is estimated that almost half the urban peak load of energy consumption is used to satisfy air-conditioning cooling demands in summer time. Since the urbanization rate in developing countries -like the case in Egypt -is rising rapidly, the pressure placed on energy resources to satisfy inhabitants' indoor comfort requirements is consequently increasing too. This paper introduces passive cool roof as a means of reducing energy cooling loads for satisfying human comfort requirements in a hot climate. A designed algorithmic hybrid matrix was used to simulate 37 roof design probabilities alternating roof shape, roof material and construction. The result of using a vault roof with high albedo coating shows a fall of 53% in discomfort hours and saves 826 kW h during the summer season compared to the base case of the conventional non insulated flat roof in a typical Cairo residential buildings. It is recommended that the selected cool roof solution be combined with natural ventilation to increase the indoor thermal comfort, and with passive heating strategies to compensate the increase in heating hours. The application is intended for low cost residential buildings in a hot dry climate.

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Section: The Effect Of Materials Variables On Heat Gainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings

Dabaieh

Wanas

Amer³

et al. 2015

Energy and Buildings

145

View full text Add to dashboard Cite

show abstract

“…Additionally, in cold weather, it can avoid heat losses, by increasing the energy efficiency of the whole building. Due to these facts, the application of different types of thermal insulation and special building materials significantly increased in recent years [19] and became a valuable strategy for making buildings more sustainable [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Hygrothermal Dynamic and Mould Growth Risk Predictions for Concrete Tiles by Using Least Squares Support Vector Machines

2017

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Abstract:The hygrothermal analysis of roofs is relevant due to the large areas exposed to a wide range of weather conditions, these directly affecting the energy performance and thermal comfort of buildings. However, after a long life service, the solar absorptivity coatings of roofs can be altered by mould accumulation. Based on two well established mathematical models, one that adopts driving potentials to calculate temperature, moist air pressure and water vapor pressure gradients, and the other to estimate the mould growth risk on surfaces, this research introduces an approach to predict mould growth considering a reduced computational effort and simulation time. By adopting multiple MISO (Multiple-Input, Single-Output) Nonlinear AutoRegressive with eXogenous inputs (NARX) models, a machine learning technique known as Least Squares Support Vector Machines (LS-SVM), a maximum margin model based on structural risk minimization, was used to predict vapor flux, sensible heat flux, latent heat flux, and mould growth risk on roof surfaces. The proposed model was validated in terms of the Multiple Correlation Coefficient (R 2 ), Mean Square Error (MSE) and Mean Absolute Error (MAE) performance indices considering as input the weather file from Curitiba city-Brazil, showing consistent precision when compared to the results of a validated numerical model.

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“…The energy saving potentials of cool roofs have been recognized; they can reduce cooling costs with a possible small increase in heating costs [22,23], they have a positive effect on the quality of life in urban areas [24,25], they can lead to an offsetting of CO 2 emissions [26][27][28], and they can be an effective strategy in cold regions as well [29][30][31]. Strong efforts have been made to investigate innovative cool materials such as retroreflective materials (RR) [32][33][34], thermo chromic pigments [35], and directional reflective materials [36].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of the Effect of Geometry and Façade Materials on Urban District’s Equivalent Albedo

et al. 2017

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Urban Heat Island (UHI) is influenced by urban form, geometry, and the properties of surfaces. Retroreflective (RR) materials have been proposed as a countermeasure to UHI, thanks to their optical property of reflecting most of the incident solar energy back towards the same direction. In this paper, the effect of RR materials on urban districts was investigated. They were applied on building façades of urban districts with different urban forms and orientations. To this aim, an experimental model resembling urban districts with different geometries was built and RR materials on vertical surfaces were tested and compared to conventional construction materials with similar global reflectance. The trend of the instantaneous albedo was monitored during the day and a new parameter called "equivalent albedo" was used to demonstrate the effectiveness of the RR materials. The comparative analysis shows that the RR façades lead to an increase of the equivalent albedo for all of the investigated urban patterns. For a block pattern, the equivalent albedo increase is equal to 3%, while for canyon patterns it is equal to 7%. Results of energy evaluations show that the energy savings obtainable with the use of RR materials is comparable to the values of anthropogenic heat emissions in residential areas.

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Potential energy savings from cool roofs in Spain and Andalusia

Cited by 95 publications

References 22 publications

Reducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings

Reducing cooling demands in a hot dry climate: A simulation study for non-insulated passive cool roof thermal performance in residential buildings

Hygrothermal Dynamic and Mould Growth Risk Predictions for Concrete Tiles by Using Least Squares Support Vector Machines

Experimental Analysis of the Effect of Geometry and Façade Materials on Urban District’s Equivalent Albedo

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