Sierpinski's forest: New technology of cool roof with fractal shapes

Sakai, Satoshi; Nakamura, Masaki; Furuya, Kenji; Amemura, Naoki; Onishi, Masanori; Iizawa, Isao; Nakata, J.; Yamaji, Kunihiko; Asano, R.; Tamotsu, K.

doi:10.1016/j.enbuild.2011.11.052

Cited by 29 publications

(10 citation statements)

References 1 publication

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“…If the influence of long-wave radiation was ignored, complete shielding of solar radiation decreased the MRT by 15 • C. Even if the evaporation rate E was 0 L/(m 2 h), when the solar radiation absorptance of the adaptation measures a was less than 0.1, the surface temperature T s was almost the same as the air temperature. A fractal-shaped sunshade was developed focusing on the utilization of the effect caused by increasing the heat transfer coefficient [17]. As the heat transfer coefficient h increased, the surface temperature T s approached the air temperature value regardless of the solar absorptance a and evaporation rate E. When the shape factor between the human body and the adaptation measures Φ and solar absorptance a were large, the MRT increased due to the effect of long-wave radiation from the adaptation measures.…”

Section: Discussionmentioning

confidence: 99%

“…The surface temperature Ts when the heat transfer coefficient h is 46 or 92 W/(m 2 K) is shown in Figure 9. A fractal-shaped sunshade was developed focusing on the utilization of the effect caused by increasing the heat transfer coefficient [17]. As the heat transfer coefficient h increased, the surface temperature Ts approached the air temperature value regardless of the solar absorptance a and evaporation rate E. The relationship between the surface temperature T s of the adaptation measures and the solar absorptance a when the heat transfer coefficient h is 23 W/(m 2 K), emissivity ε is 0.97, and net infrared radiation q is −93 W/m 2 for different values of the evaporation rate E is shown in Figure 8.…”

Section: Mrt and Surface Temperature Reduction Evaluationmentioning

confidence: 99%

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A Simple Method to Evaluate Adaptation Measures for Urban Heat Island

Takebayashi

2018

Environments

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In recent years, adaptation measures such as awnings, louvers, directional reflective materials, mist sprays, and evaporative materials, have been developed with the expectation that they will serve as effective solutions to outdoor human thermal environments that are under the influence of urban heat island. A simple method to evaluate the aforementioned adaptation measures is examined in this study, focusing on their appropriate introduction on urban space. The influence of the solar transmittance of adaptation measures such as shading, on mean radiant temperature (MRT) is approximately 1.5 • C per 0.10. If a shielding device that reflects a large amount of solar radiation and facilitates high levels of evaporation is developed, MRT and standard new effective temperature (SET*) will both decrease.

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Section: Discussionmentioning

confidence: 99%

Section: Mrt and Surface Temperature Reduction Evaluationmentioning

confidence: 99%

A Simple Method to Evaluate Adaptation Measures for Urban Heat Island

Takebayashi

2018

Environments

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“…It can be obtained in different forms (blue, gray and green). Sierpinski roof: It allows a better temperature distribution on the surface due to its fractals with a small exposure area; lower temperatures are obtained [37]. Flectofin louvers: Operates without hinges and with 90 • displacements.…”

Section: Swot Analysis Strengths Weaknessesmentioning

confidence: 99%

“…Renewable hydrogen: Probability of leakage, volatile, needs a lot of logistical and storage care. Green requires high renewable energy generation and is expensive to produce (electrolysis).Sierpinski roof: Partially transmits sunlight [37]. Flectofin blinds: They do not have automatic control, so they would have to be adapted.…”

Section: Swot Analysis Strengths Weaknessesmentioning

confidence: 99%

Sustainability Assessment of the Anthropogenic System in Panama City: Application of Biomimetic Strategies towards Regenerative Cities

et al. 2021

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To understand the sustainability problem for Panama’s metropolitan area, its urban metabolism was investigated. A way to evaluate its current state was obtained by estimating a sustainable indicator based on the Green City Index. With the abstraction of the identified problems, the biomimetic strategy “problem-based approach” was carried out, where different pinnacles of nature were selected as a reference for the design of regenerative solutions. These were inspired by the understanding of the living world and how to include ecosystems in urban designs. Therefore, a framework was proposed for positive generation and natural solutions in cities to take advantage of the regenerative potential in Panama City. Using ecosystem services, a set of indicators were developed to measure regeneration over the years at the city scale. The results indicate that from the 11 selected pinnacles, 17 solutions inspired in nature were proposed to regenerate cities. Consequently, a SWOT analysis was realized along with a questionnaire by experts from different fields. The findings obtained show that the feasible solutions were: arborization, green facades, solar roofs, e-mobility, green corridors, bicycle lanes, sidewalks, and biofilters. This research represents a step towards creating and developing regenerative cities, thus improving the quality of life of living beings and ecosystems present in society.

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“…UHI mitigation measures include installing green roofs (e.g., Razzaghmanesh et al, 2016;Smith & Roebber, 2011;Takebayashi & Moriyama, 2007; N. H. Wong et al, 2003), installing cool roofs (e.g., Akbari & Kolokotsa, 2016;Razzaghmanesh et al, 2016;Sharma et al, 2016;Synnefa et al, 2006;Tewari et al, 2019), use of cool pavements (Erell et al, 2014;Qin, 2015;Santamouris et al, 2012;Synnefa et al, 2011), improving the ventilation function of cities (e.g., Tan et al, 2016; M. S. , and urban irrigation (e.g., Broadbent et al, 2018;Wang et al, 2019). Outdoor thermal comfort improvement and heat stress mitigation measures include planting trees along streets (e.g., Armson et al, 2012;Coutts et al, 2016;Manickathan et al, 2018;Rahman et al, 2018), installing artificial shading devices (e.g., Elgheznawy & Eltarabily, 2021;K antor et al, 2018;Sakai et al, 2012;Vanos et al, 2017), and spraying dry mist (e.g., Huang et al, 2017;Montazeri et al, 2015Montazeri et al, , 2017Ulpiani et al, 2019;N. H. Wong & Chong, 2010).…”

Section: Introductionmentioning

confidence: 99%

Wisteria trellises and tents as tools for improved thermal comfort and heat stress mitigation: Meteorological, physiological, and psychological analyses considering the relaxation effect of greenery

Kusaka

Asano

Kimura

2022

Meteorological Applications

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In this study, wet-bulb globe temperature (WBGT) was measured under wisteria trellises, under tents, and in direct sunlight. In addition, a subject experiment was conducted to consider the relaxation effect of the greenery. In terms of WBGT, the risk of heatstroke under the wisteria trellis was one level lower than that in direct sunlight. The mitigation effect of the wisteria trellis was greater than that of the tent. The difference in WBGT beneath the wisteria trellis and under the tent was primarily due to varied black-globe temperature (i.e., the difference in radiation environment). The wisteria trellis blocked most of the solar radiation, and its effect on the small aggregation of leaves reduced the increase in the leaf surface temperature and downward longwave radiation. The tent material allowed more solar radiation and increased the temperature of the tent surface. The questionnaire responses revealed that the subjects felt cooler and more comfortable under the wisteria trellis than under the tent, with or without a blindfold. K E Y W O R D Sheat stress mitigation, thermal comfort improvement, urban heat island mitigation, urban trees, wet-bulb globe temperature, wisteria trellises

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Sierpinski's forest: New technology of cool roof with fractal shapes

Cited by 29 publications

References 1 publication

A Simple Method to Evaluate Adaptation Measures for Urban Heat Island

A Simple Method to Evaluate Adaptation Measures for Urban Heat Island

Sustainability Assessment of the Anthropogenic System in Panama City: Application of Biomimetic Strategies towards Regenerative Cities

Wisteria trellises and tents as tools for improved thermal comfort and heat stress mitigation: Meteorological, physiological, and psychological analyses considering the relaxation effect of greenery

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