Simulating the effects of cool roof and PCM (phase change materials) based roof to mitigate UHI (urban heat island) in prominent US cities

Roman, Kibria K.; O’Brien, Timothy J.; Alvey, Jedediah B.; Woo, OhJin

doi:10.1016/j.energy.2015.11.082

Cited by 161 publications

(66 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In order to solve the increasingly serious problem of UHI, some effective measures should be adopted immediately. In addition to planting more trees, pavements and roves with high albedo and low heat storage should be applied to mitigate the UHI [52,53].…”

Section: Temporal Trends Of Ues On Vegetation and Suhii In Yrb Chinamentioning

confidence: 99%

Urbanization Effects on Vegetation and Surface Urban Heat Islands in China’s Yangtze River Basin

et al. 2017

View full text Add to dashboard Cite

Abstract:In the context of rapid urbanization, systematic research about temporal trends of urbanization effects (UEs) on urban environment is needed. In this study, MODIS (Moderate Resolution Imaging Spectroradiometer) land surface temperature (LST) data and enhanced vegetation index (EVI) data were used to analyze the temporal trends of UEs on vegetation and surface urban heat islands (SUHIs) at 10 big cities in Yangtze River Basin (YRB), China during 2001-2016. The urban and rural areas in each city were derived from MODIS land cover data and nighttime light data. It was found that the UEs on vegetation and SUHIs were increasingly significant in YRB, China. The ∆EVI (the UEs on vegetation, urban EVI minus rural EVI) decreased significantly (p < 0.05) in 9, 7 and 5 out of 10 cities for annual, summer and winter, respectively. The annual daytime and nighttime SUHI intensity (SUHII; urban LST minus rural LST) increased significantly (p < 0.05) in 10 and 4 out of 10 cities, respectively. The increasing rate of daytime SUHII and the decreasing rate of ∆EVI in old urban areas were much less than the whole urban area (0.034 • C/year vs. 0.077 • C/year for annual daytime SUHII; 0.00209/year vs. 0.00329/year for ∆EVI). The correlation analyses indicated that the annual and summer daytime SUHII were significantly negatively correlated with ∆EVI in most cities. The decreasing ∆EVI may also contribute to the increasing nighttime SUHII. In addition, the significant negative correlations (r < −0.5, p < 0.1) between inter-annual linear slope of ∆EVI and SUHII were observed, which suggested that the cities with higher decreasing rates of ∆EVI may show higher increasing rates of SUHII.

show abstract

Section: Temporal Trends Of Ues On Vegetation and Suhii In Yrb Chinamentioning

confidence: 99%

Urbanization Effects on Vegetation and Surface Urban Heat Islands in China’s Yangtze River Basin

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Both cool roof and PCM roof can help to decrease the cooling load demand [14]. A coating having high reflectivity can contribute to reduce the amount of absorbed radiation, and the PCM approach can reduce the sensible heat.…”

Section: Introductionmentioning

confidence: 99%

Designing multifunctional pigments for an improved energy efficiency in buildings

Aranzabe

Arriortúa

Larrañaga

et al. 2017

Energy and Buildings

View full text Add to dashboard Cite

Buildings are responsible for 40% of the total energy use and 36% of total GHG emissions within the EU. Materials science offers solutions that when combined can offer energy savings in building sector. In this study, high reflectance coating and thermal storage capacity are combined with the aim of improving energy efficiency in buildings. For this issue a multifunctional pigment having a phase change material adsorbed on its surface and a high total solar reflectance has been manufactured.The total solar reflectance of the pigment will make the paint to reflect the sunlight radiation in the infrared part of the spectrum reducing the amount of absorbed radiation.This high reflection provides a surface level effect as is a passive stimulus-responsive solution that acts with sunlight radiation.On the other hand, the thermal storage capability provides a bulk level effect as is passive stimulus-responsive solution acting by temperature changes, making it possible to use constructive materials as a thermal energy storage media. The preparation process is described and the pigment is characterized conveniently. The thermal performance of corresponding pigmented coatings was evaluated by a simulated experiment in which two boxes were covered with the coating containing the multifunctional pigment and traditional pigmented coating on their tops. The indoor air temperature and the interior temperature of the substrate were measured obtaining differences of 4-5•C.

show abstract

“…The numerical investigation by (Aguilar et al, 2013) extended previous work by considering the impact of PCM embedded in roofing module on cooling energy and showed that solar reflectance is the parameter with the biggest impact, but PCMs may be worthwhile in locations where the reflectance may undergo a sharp decrease due to soiling; moreover, they verified that simulation is a powerful tool for the involved multi-parameter analyses. Roman et al, 2016 showed through simulation that a PCM allows a sharp decrease of the maximum through-roof heat gain at a wide range of albedo. In (Chou et al, 2013) the coupling of a metal sheet cool roofing structure with a PCM was studied in order to absorb the downward heat flow induced by incident solar radiation and then release it back to the environment by convection during the nocturnal cycle; experimental and numerical analyses showed that the downward thermal flow through the roof into the house can be significantly reduced.…”

Section: Phase Change Materials and Their Coupling With Cool Roof Surmentioning

confidence: 99%

Coupling of Solar Reflective Cool Roofing Solutions with Sub-Surface Phase Change Materials (PCM) to Avoid Condensation and Biological Growth

Muscio

2016

ESSD

View full text Add to dashboard Cite

Cool roofs are effective solutions to counter the overheating of building roofs, inhabited spaces below and urban areas in which buildings are located thanks to their capability of reflecting solar radiation. Nonetheless, the relatively low surface temperatures that they induce can cause condensation of humidity and leave the surface wetted for large part of the day, thus promoting the growth of bacteria, algae and other biological fouling; this can cause a quick decay of the solar reflective performance. Biological growth is countered by surface treatments, which, however, may be toxic and forbidden in many countries and may also vanish quickly. It can also be countered by lowering the thermal emittance and thus decreasing heat transfer by infrared radiation to the sky and the consequent night undercooling, but this can decrease the performance of cool roofs. An alternative approach, which is analyzed in this work, is to embed in the first layer below the cool roof surface a phase change material (PCM) that absorbs heat during the daytime and then releases it in the nighttime. This can increase the minimum surface temperatures, thus reducing the occurrence humidity condensation and also the biological growth. In this work, preliminary results on the coupling of a cool roof surface with a PCM sublayer are presented, being obtained by theoretical investigation on commercial materials and taking into account the time evolution pattern of the environmental conditions.

show abstract

Simulating the effects of cool roof and PCM (phase change materials) based roof to mitigate UHI (urban heat island) in prominent US cities

Cited by 161 publications

References 31 publications

Urbanization Effects on Vegetation and Surface Urban Heat Islands in China’s Yangtze River Basin

Urbanization Effects on Vegetation and Surface Urban Heat Islands in China’s Yangtze River Basin

Designing multifunctional pigments for an improved energy efficiency in buildings

Coupling of Solar Reflective Cool Roofing Solutions with Sub-Surface Phase Change Materials (PCM) to Avoid Condensation and Biological Growth

Contact Info

Product

Resources

About