Analytical solution for the study of time lag and decrement factor for building walls in climate of Iran

Fathipour, Reza; Hadidi, Amin

doi:10.1016/j.energy.2017.06.009

Cited by 58 publications

(16 citation statements)

References 33 publications

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“…When analyzing the capacity of a heterogeneous construction section to attenuate thermal amplitudes, the decrement factor ( f ) [55] is used. This value relates the thermal amplitudes of the interior and exterior space [56] and its value depends on the thickness and effusivity of each material in the section.…”

Section: Effusivity and Decrement Factormentioning

confidence: 99%

Water-Covered Roof Versus Inverted Flat Roof on the Mediterranean Coast: A Comparative Study of Thermal and Energy Behavior

Espinosa-Fernández

Iribarren

Sáez³

2020

Applied Sciences

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Reservoir, or water-collecting roofs present greater thermal inertia than inverted flat roofs due to the mass of water they contain. This feature gives them better thermal performance and leads to greater stability in the indoor air temperature Ti and the wall surface temperatures. In the summer, they can dampen the effect of solar radiation and regulate external thermal loads thanks to their greater effusivity and thermal capacity. This research compares the thermal behavior of the roofs of two buildings located in Alicante on the Spanish Mediterranean coast: a loft flat in the city center and a water-covered roof in the Museum of the University of Alicante (MUA). Values for effusivity, diffusivity, thermal capacity, decrement factor, time lag and internal, as well as external thermal admittance were obtained. After monitoring both roofs during 2014, behavior simulations were performed in Design Builder using 6 different scenarios reflecting different combinations in both buildings of water-covered, inverted and conventional roofs and marble or terrazzo paving. The water-covered roof led to a higher decrement factor and time lag, as well as to a reduction of annual energy demands between 8.86% and 9.03%.

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Section: Effusivity and Decrement Factormentioning

confidence: 99%

Water-Covered Roof Versus Inverted Flat Roof on the Mediterranean Coast: A Comparative Study of Thermal and Energy Behavior

Espinosa-Fernández

Iribarren

Sáez³

2020

Applied Sciences

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“…As some of these studies [1][2][3][4][5][6] have been developed under steadystate, thermal inertia effects of building' external walls are not taken into account. It is known that thermal inertia has a significant effect on time-dependent heat transfer from the external walls [7][8][9][10][11][12][13][14][15][16][17]. Arslanoglu and Yigit [1] calculated optimum insulation thickness for different regions of Turkey namely, Ankara, Erzurum, Istanbul, Izmir in order to use 1-D steady-state heat transfer model.…”

Section: Introductionmentioning

confidence: 99%

“…The thermal performance of various external wall structures based on wall orientation, wall thickness and insulation location based on different climate zones in Turkey were numerically analyzed in terms of time-dependent thermal behaviors. Fathipour and Hadidi [8] investigated time lag and decrement factor for different building materials for exterior walls solved analytically using Green function under time-dependent convection boundary conditions in Iran. Nematchoua et al [9] optimized the thermal insulation thickness in equatorial and tropical climate regions based on energy usage and pay-back period analysis with the numerical solution of transient heat transfer through multilayer walls related to the average outdoor temperature, solar radiation, and shading effect.…”

Section: Introductionmentioning

confidence: 99%

A full 34 factorial experimental design for the low energy building’s external wall

2020

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The low energy building concept is based on improving the building envelope to reduce heating and cooling loads. Improvements in building envelopes depend not only on climatic conditions but also on insulation. In this study, the thermal performance of external walls was studied by using a three-level full factorial statistical experimental design. An opaque wall in low energy buildings was chosen in order to study the effect of selected factors of city (A), orientation (B), insulation location (C), and month of the year (D) on heat loss or gain. A software was used to calculate the ANOVA table. As a result, all three factors of months of the year, city and orientation of the building façade were found to be significant factor effects for heat transfer. Two-factor interactions of AB, AD, BD, and CD were found to be significant. Therefore, the effects of season, location and orientation were successfully shown to be effective parameters.

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“…He showed that the thickness and position of the insulation have a very important effect on the time lag and the decrement factor. Fathipour and Hadidi (2017) have investigated the time lag and decrement factor of different building materials that are prevalently used in Iran. They concluded that the values of time lag and decrement factor change with wall thickness for all types of building material.…”

Section: Introductionmentioning

confidence: 99%

Influence of envelope thickness and solar absorptivity of a test cell on time lag and decrement factor

Toure

Dieye

Gueye

et al. 2019

Journal of Building Physics

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This work deals with the influence of envelope thickness and solar absorption on the time lag and the decrement factor. For this, a test cell of 1 m3 of volume is built with a material commonly used in construction in Senegal, the compressed earth brick stabilized with cement. The ambient-air temperature inside and outside of test cell and solar direct normal irradiance is measured. The test cell is modeled using EnergyPlus software. The comparison of experimental and theoretical ambient-air temperature puts out a great linear showing the reliability of the model. The time lag and the decrement factor are calculated using the air-sol equivalent temperature of the test cell and the inside ambient-air temperature. The time lag and decrement factor of the compressed stabilized earth brick envelope are respectively 0.22 and 6.6 h showing the good thermal inertia of those bricks. A parametric study is performed to determine the effect of envelope thickness and solar absorptivity on the time lag and decrement factor. The results show that the decrement factor decreases with envelope thickness while the time lag increases linearly and that an envelope thickness of 32 cm has a decrement factor of around zero with a maximum time lag of about 12 h for this type of material. The envelope’s solar absorption has a moderate effect on the decrement factor and time lag.

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Analytical solution for the study of time lag and decrement factor for building walls in climate of Iran

Cited by 58 publications

References 33 publications

Water-Covered Roof Versus Inverted Flat Roof on the Mediterranean Coast: A Comparative Study of Thermal and Energy Behavior

Water-Covered Roof Versus Inverted Flat Roof on the Mediterranean Coast: A Comparative Study of Thermal and Energy Behavior

A full 34 factorial experimental design for the low energy building’s external wall

Influence of envelope thickness and solar absorptivity of a test cell on time lag and decrement factor

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