Increasing the southern side-slope albedo remedies thermal asymmetry of cold-region roadway embankments

Qin, Yinghong; Jia, Liang; Luo, Zhenxian; Tan, Kanghao; Zhu, Zhen Yu

doi:10.1016/j.coldregions.2015.12.006

Cited by 29 publications

(4 citation statements)

References 19 publications

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“…Thermally-induced stresses attack the upper fixed end of the exposed, cantilevered part ( Figure 2) in most pronounced manner. During the daytime, solar radiation heats up the upper side of the exposed part whereas the lower side remains relatively cold [19]. Different temperature through a concrete structure leads to different deformation potentials, resulting in the cantilevered part being downward bent.…”

Section: Thermally-induced Stressmentioning

confidence: 99%

“…The exposed part of the duct thus experiences a lower level of differential thermally-induced stresses. When the insulation is of white texture, it can reflect the solar radiation to the air [19], lessening the heat absorption during the summer time and thus enhancing the cooling effect of the ducts. Therefore, using white geo-textile or organic foam to insulate the outer ring of the duct is expected to effectively lessen the thermally induced stresses through the duct.…”

Section: Insulating the Exposed Endmentioning

confidence: 99%

“…So far, numerical studies and field observations, as well as some associated heat-transfer theoretical analysis, are stood on an uncorroborated assumption that the ducts would structurally sustain during their expected lifetime (50 years) [16]. Although in the last decade, there are extensive studies on the techniques of keeping roadbeds in permafrost regions by reducing the solar absorption [17][18][19], enhancing the air convection [20,21], and their combinations [22,23], the long-term structural stability of air ventilation ducts remains unknown and has not been reported yet. As most of ventilation ducts are of concrete texture, it is questionable whether the ducts remain structurally intact during their lifetime.…”

Section: Introductionmentioning

confidence: 99%

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A Preliminary Study on the Long-Term Structural Stability of Ventilation Ducts in Cold Regions

et al. 2019

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The construction of roadways in permafrost regions modifies ground-surface conditions and consequently, negatively varies thermal stability of the underlying frozen soils. To avoid the thawing of the permafrost layer under the scenario of global warming, roadways are usually laid on a built-up embankment, which not only disperses the traffic loads to underlying layers but also minimize the thermal disturbance. In the embankment, duct ventilation, or called air duct, can be embedded to further cool the underlying permafrost. While the thermal performance of duct ventilations has been well documented, the long-term structural stability of duct ventilation remains unknown. This study examines the structural stress of ventilation ducts that are placed in harsh weather such as the Qinghai-Tibet Plateau. The ducts are currently buried in the embankment filler, with the wind-outlet and -inlet ends exposed and cantilevered out of the embankment. Field studies found that the exposed parts have plagued cracking and even failures, especially at the fixed end of the cantilevered part. Damages of these concrete ducts are attributed to cyclic freezing-thawing attack, thermally-induced stresses, moisture-induced stresses, and concrete swelling. These physical attacks are caused by the harsh weather in the Qinghai-Tibet plateau. It is recommended to insulate the exposed part of the ducts and to fabricate durable and dense concrete ducts.

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Section: Thermally-induced Stressmentioning

confidence: 99%

Section: Insulating the Exposed Endmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Preliminary Study on the Long-Term Structural Stability of Ventilation Ducts in Cold Regions

et al. 2019

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“…Several factors affect the performance of solar-related systems including the absorption specifications of the applied materials, solar radiation of the region, operating condition (such as the temperature and daylight hours) and etc. (Qin, 2016;Qin, Liang, Luo, Tan, & Zhu, 2016;Qin, Liang, Tan, & Li, 2016). These parameters must be considered for modeling and designing solar energy technologies.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of electrical efficiency of photovoltaic thermal solar collector

Ahmadi

Baghban

Sadeghzadeh

et al. 2020

Engineering Applications of Computational Fluid Mechanics

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Solar energy is a renewable resource of energy that is broadly utilized and has the least emissions among the renewable energies. In this study, machine learning methods of artificial neural networks (ANNs), least squares support vector machines (LSSVM), and neuro-fuzzy are used for advancing prediction models for thermal performance of a photovoltaic-thermal solar collector (PV/T). In the proposed models, the inlet temperature, flow rate, heat, solar radiation, and the sun heat have been considered as the inputs variables. Data set has been extracted through experimental measurements from a novel solar collector system. Different analyses are performed to examine the credibility of the introduced approaches and evaluate their performance. The proposed LSSVM model outperformed ANFIS and ANNs models. LSSVM model is reported suitable when the laboratory measurements are costly and time-consuming, or achieving such values requires sophisticated interpretations. Keywords: Renewable energy; neural networks (NNs); adaptive neuro-fuzzy inference system (ANFIS); least square support vector machine (LSSVM); photovoltaic-thermal (PV/T); hybrid machine learning model

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Presentation of new approach for energy consumption reduction with use of solar system

Sani

Ayani

Behbahani-nia

et al. 2020

J Therm Anal Calorim

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Increasing the southern side-slope albedo remedies thermal asymmetry of cold-region roadway embankments

Cited by 29 publications

References 19 publications

A Preliminary Study on the Long-Term Structural Stability of Ventilation Ducts in Cold Regions

A Preliminary Study on the Long-Term Structural Stability of Ventilation Ducts in Cold Regions

Evaluation of electrical efficiency of photovoltaic thermal solar collector

Presentation of new approach for energy consumption reduction with use of solar system

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