Alexandru Gherega’s Post

Urban areas are generally warmer than more rural areas. This is known as the "heat island effect". To quantify the performance of building materials with the aim of reducing this effect, we measure a parameter called solar reflectance index, or SRI for short. This in turn requires that we measure solar reflectance and emissivity of a material. For full details, read this interesting blog by Russell Bailey.

A new study from UCL reveals that white or reflective "cool roofs" are the most effective way to combat urban heat. Researchers used a 3D climate model to test various cooling methods in London. Cool roofs reduced average temperatures by 1.2°C, outperforming solar panels and vegetation. Surprisingly, green roofs had minimal cooling impact. While air conditioning cooled indoor spaces, it warmed outdoor areas. Cool roofs not only lower city temperatures but also reduce indoor cooling needs, offering a dual benefit against rising urban heat. This study highlights a key strategy for heat management. Read more https://bit.ly/4cMfl0x #UrbanHeat #CoolRoofs #ClimateChange #SustainableCities #RandD #RandDProjects #RandDtaxRelief #TaxConsultant #Consultancy

🎈 Colour has a significant impact on heat absorption, as properly indicated by this experiment. This is why promoting 𝐰𝐡𝐢𝐭𝐞 𝐫𝐨𝐨𝐟𝐬 and avoiding 𝐝𝐚𝐫𝐤-𝐜𝐨𝐥𝐨𝐮𝐫𝐞𝐝 𝐫𝐨𝐨𝐟𝐬 in cities is crucial to reducing heat islands and improving urban thermal comfort. 🏙 Increasing the #albedo of urban surfaces has received attention as a strategy to mitigate urban heat islands. Light-coloured surfaces return a large part of the sunrays back to the atmosphere (high albedo). Dark surfaces absorb the rays from the sun (low albedo). 1️⃣ A study examined the impact of white roofs on urban temperature using a global climate model. The findings showed that, on average across all urban areas, implementing 𝐰𝐡𝐢𝐭𝐞 𝐫𝐨𝐨𝐟𝐬 𝐰𝐨𝐮𝐥𝐝 𝐥𝐞𝐚𝐝 𝐭𝐨 𝐚 𝟑𝟑% 𝐫𝐞𝐝𝐮𝐜𝐭𝐢𝐨𝐧 𝐢𝐧 𝐭𝐡𝐞 𝐚𝐧𝐧𝐮𝐚𝐥 𝐦𝐞𝐚𝐧 𝐡𝐞𝐚𝐭 𝐢𝐬𝐥𝐚𝐧𝐝 𝐞𝐟𝐟𝐞𝐜𝐭. 2️⃣ The effectiveness of white roofs depends on several factors. Research has shown that painting the roof white is more effective when the roof is located in places with more solar radiation, lower wind speed, and less precipitation, and when the roof has less water-holding capacity and smaller thermal admittance. 3️⃣ Researchers have strongly recommended that building code policies phase out dark-coloured roofs in warm climates to protect against their adverse public health externalities. 🛣 Moreover, white pavements and roads are suggested as a method for reducing urban heat islands. Video credit: Pareekh Jain 1) K. W. Oleson et al. 2010; Effects of white roofs on urban temperature in a global climate model 2) Linying Wang et al. 2020; Where Are White Roofs More Effective in Cooling the Surface? 3) Julian Sproul et al. Julian Sproul; Economic comparison of white, green, and black flat roofs in the United States #whiteroofs #urbandesign #coolcities #roof #pavement #roads

Parametric Architecture With the increasing temperature of the Earth, can we find ways to cool down our cities? The impact of heat is felt by everyone, but it affects people living in cities more than those in suburban or rural areas. The urban heat island effect is responsible for the higher temperatures experienced in many cities worldwide. This increase in temperature is mainly due to climate change and the growing number of heat islands in urban areas. So, with the increasing temperature of the Earth, can we find ways to cool down our cities?

Green Air Conditioner Windcatchers of Yazd in Iran are an example of smart architecture that has adapted to the climate. Windcatchers ventilate and cool the air without the need for electricity.

The relationship between overheating and urban micro envitonment in Helsinki, Finland based on a large dataset of actual hourly indoor temperatures٫ is analyzed in our recent paper. Check it out for more detailed info. #overheating #climatechange #microclimate

"...specifiers, despite the dangerously hot summers of recent years, often adopt a ‘cold climate’ outlook and consider shading products superfluous." As our climate changes and building fabric standards rise, so must our design approach. Great guidance document attached to this article looking at 19 different shading devices to help prevent overheating in buildings. #Overheating #SustainableArchitecture #ClimateAdaptation https://lnkd.in/e5UcbJPb

Block thermal environments affect public health and the sustainable development of cities. However, the study of spatial heterogeneity of block morphology in thermal environments needs further research, and exploring a new classification system of block morphology will also be beneficial to urban management. Taking 1426 blocks of Dalian city as an example, this paper proposed a new classification system of block morphology (HDR system) by a two-step cluster. Pearson coefficient, ordinary least squares (OLS) model, and geographically weighted regression (GWR) model were applied to explore the mechanisms of building height (BH), building density (BD), and plot ratio (PR) on land surface temperature (LST) globally (non-classification) and locally (classification system HDR1–5) respectively. The results are as follows: 1) Low-floor buildings dominate Dalian’s blocks. 2) Greater intensity of block development is associated with greater LST. 3) BH, BD, and PR show significant spatial heterogeneity on LST. 4) LST is most notably affected by BD. 5) HDR5 is recommended as the preferred block plan to face the worsening of the thermal environment. The results of this study provide direct references and implications for city managers and designers who want to develop practical and sustainable policies and norms for urban renewal and new blocks.

How can you use the tools of ENVI-met to improve urban quality of life and mitigate the effects of climate change? There is no doubt that urban vegetation - from green roofs and facades to street trees, is one of the main solutions for these purposes. However, urban trees need to be healthy and in a suitable environment to thrive, but they often face hostile conditions: limited rooting space, insufficient light and extremes of humidity can hinder their development. Complex urban wind patterns can double local wind speeds, causing damage from broken branches to complete tree collapse, posing risks to both tree infrastructure and citizens. Sustainable urban landscaping requires optimal locations, species and maintenance strategies for urban trees. With ENVI-met you can visualise and assess the vulnerable parts of a tree in a specific location, which would not be visible without simulation, as we have shown in that image. Get started with ENVI-met today and enhance your urban planning projects: www.envi-met.com #landscapearchitecture #microclimate #airquality #trees #urbanplanning #sustainability #cities #climatechange

Due to climate change, there is an increased risk of apartment overheating. Our latest paper evaluated the influence of the urban microenvironment on residential building indoor air temperature via green view index (GVI), floor area ratio and distance from the sea. We analyzed a large dataset of over 2000 apartments in the Helsinki region during summers of 2018 and 2021, where severe heatwaves were presented. The results showed consistent correlations between clustered groups and microenvironment parameters, where the best-performing group had an indoor air temperature of about 1 °C lower than the average during the summers and 0.7 °C lower during the severe heatwaves. Building groups with higher GVI demonstrated a greater ability to endure long heatwaves. A substantial influence of sea distance and floor area ratio was observed during short heatwaves in the middle and late summer. https://lnkd.in/dEZ9VYVN