© Paul Vu Photography

White Paint Can Cool Down Our Heating Cities

由专筑网邢子，小R编译

气候已经发生了变化，人们也一直在努力应对诸如高温、洪水、干旱等自然问题。随着世界转向缓解危机的策略，建筑和施工行业处于相对重要的位置，其选择可以产生一定程度的影响。其中包括一些可以解决复杂问题创新产品，例如在高度密集的城市中降低温度。

联合国环境规划署（UNEP）估计，城市占全球二氧化碳排放量的75%，而建筑物是最大的罪魁祸首。城市热岛效应发生在建筑物和道路吸收太阳的热量，并在整个晚上散发热量，促使温度持续上升。在建筑物高度集中的城市，很少有绿色植物或自然景观，这种效应变得更加突出，在潮湿的气候和密集的人口中可能更加严重。一些因素还包括人造建筑材料、城市几何学、人类产生的热量以及整体天气和地理环境。

The climate has changed, and we have been left grappling with the consequences: high temperatures, flooding, drought and much more. As the world shifts (or tries to shift) to ways to mitigate the crisis, the architecture and construction industry finds itself in a particularly important position whose choices can create real impact. Some of these choices can include innovative products that offer real solutions to complex problems, such as the cooling down of temperatures in highly dense cities.
The United Nations Environment Programme (UNEP) estimates that cities account for 75% of global CO2 emissions, with buildings being one of the biggest culprits. The urban heat island effect occurs when buildings and roads absorb the heat from the sun and emanate this heat throughout the night, contributing to a constant increase in temperatures. In cities with a high concentration of structures and very little greenery or natural landscapes, this effect becomes heightened and can be especially dangerous in humid climates and dense populations. Some of the largest factors also include man-made building materials, urban geometry, human-generated heat and the overall weather and geography.


via United States Environmental Protection Agency

人们慢慢习以为常，如美国和加拿大西北太平洋地区的热浪，城市成为了重灾区，特别是在不太富裕和历史上被边缘化的地区，这些地区人口稠密，没有那么多的冷却系统，而且有大片的水泥，没有多少植被来有机地冷却空气。考虑到在未来的几十年里，估计会有更多的人生活在城市里，而且极端气候事件会更经常地发生，这就向建筑师和设计师提出了一个问题，即如何才能设计出不会对城市产生此类影响的建筑？

In increasingly common situations such as the heatwaves in the Pacific Northwest of the United States and Canada, cities can become the hardest hit areas, especially in less affluent and historically marginalized sectors that are densely populated, do not have as much access to cooling systems, and have large swaths of cement without much vegetation to organically cool the air. Considering that more people are estimated to be living in cities in the next decades and that extreme climate events are due to happen more regularly, this prompts the question to architects and designers: How can we design buildings that won’t have this effect on cities?


© Chao Zang

这就要说到涂料，近年来，一些创新的涂料选择已经出现，用于减轻城市的热影响。它们主要是利用白色涂料的优势来反射建筑物的热量，创造出不需要额外机械冷却系统的低温。虽然这是人口稠密的大城市中不可持续的生活方式的又一个缓解方案，建筑师历来喜欢使用混凝土，但在更复杂的解决方案还没出现时，这是一种将问题掌握在自己手中的方法。

Enter paint. A number of innovative paint options have cropped up in recent years to mitigate the effects of heat in cities. They mainly capitalize on the benefits of white paint to reflect heat off of buildings and homes and create cooler temperatures that don’t require additional mechanical cooling systems. Although this is yet another palliative solution for an unsustainable way of life in densely populated megacities –which have historically focused on the use of concrete– it is a way to take matters into our own hands, as best we can, while the more complex solutions are underway.


© Cristiano Bauce

UNStudio的The Coolest White就是其中之一。作为“建筑设计网络”，UNStudio有各种部门，从事不同类型的项目，重点关注建筑环境的未来。在设计“以人类为中心的经验，建立社会可持续发展的城市”使命下，该设计办公室创造了一种新的涂料，它具有非常高的太阳总反射率（TSR）涂层系统，使建筑物吸收和辐射的热量低于正常水平，减少建筑物内部和外部的热量。它还使涂层更有弹性，经久耐磨，有助于减少维护投资和额外的维护费用，以缓解不断变化的气候。该系统用含氟聚合物技术制成，提供了非常有保护性的涂层，特别能保持其光泽和完整性。在应用方面，它可以应用于“高质量的金属外墙元素和铝、钢、GRP等制成的钢结构，如工业和商业建筑、购物中心、加油站、桥梁、立交桥、工业OEM等”。

The Coolest White, by UNStudio, is one of these. An “architecture design network”, UNStudio has a variety of units that work on different types of projects, with a focus on the future of the built environment. On a mission to design “humanity-centric experiences to build socially sustainable cities”, the design office created a new paint with a very high total solar reflectance (TSR) coating system that allows for buildings to absorb and radiate less heat than normal, reducing the heat both inside and outside buildings. It also makes for a more resilient coating with less abrasion throughout the years, contributing to less investment in maintenance and additional elements to mitigate the changing climate. The coating system is made with fluoropolymer technology, providing a very protective coating that maintains its gloss and integrity particularly well. In terms of applications, it can be applied to “high-quality metallic façades elements and steel structures made of aluminium, steel, GRP etc. such as industrial and commercial buildings, shopping centers, petrol stations, bridges, overpasses, industrial OEM-coatings, etc.”


via Purdue University

最近推出的另一个产品来自普渡大学，其工程团队一直在研究类似的替代品。早在2020年10月，他们创造了一种超白涂料，最近被他们的最新创造所超越，这是一种更新的、更白的涂料，也能更有效地保持表面的凉爽。它能反射高达98.1%的光线，并且由于其超白性，可以使室内温度明显低于周围环境。据有关计算，这种涂料的冷却能力可达10千瓦，使其比大多数家用空调更强大。所涉及的技术源于辐射冷却，这是一种被动的日间冷却系统，通常涉及复杂和多层的结构。在这种情况下，这种效果是通过纳米粒子薄膜和纳米复合涂料实现的，它简化了必要的工具和层次。

Another recent launch comes from Purdue University, whose engineering team has been working on a similar alternative. Back in October 2020 they created an ultra-white paint which was recently outdone by their latest creation: a newer, whiter paint that is also more effective at keeping surfaces cool. It reflects up to 98.1% of light and can keep interiors significantly cooler than its surroundings, due to its ultra-whiteness. One of the professors involved calculates that the paint could have a cooling power of up to 10 kilowatts, making it more powerful than most household air conditioners. The technology involved stems from radiative cooling, a passive daytime cooling system that usually involves more complex and multi-layered structures. In this case, the effect is achieved by nanoparticle films and nanocomposite paints that simplify the necessary tools and layers.


© Paul Vu Photography

市场上也有一些其他选择，比如Rain Guard的Cool Coat，它们主要能够“反弹”紫外线，防止过多的热量进入内部。此外，还可以选择简单的白色涂料，即使没有任何特殊的防热性能，也会有助于降低整体环境的温度，或者其他环保的建筑材料，如麻质混凝土或其他混凝土和气候砖的替代品。

毫无疑问，建筑、设计和施工在气候危机中起着很大的作用。人们如何前进，也将掌握在这些选择如何设计和建造住宅、办公室和其他建筑物的专业人士手中。值得庆幸的是，一系列具有生态意识的产品不断出现，正在帮助人们为一个新的世界做出更好的选择。

Other options have also been on the market for a while longer, such as Rain Guard’s Cool Coat, which focuses on “bouncing back” UV rays to prevent too much heat from entering homes. And there is always the option of a simple white paint, which even without any special anti-heat properties, will also contribute to a cooler overall environment; or other environmentally friendly building materials, such as hempcrete or other alternatives to concrete and Climate Tiles.
There is no doubt that architecture, design and construction play a large role in the climate crisis. How we move forward will also be in the hands of the professionals who are choosing how to design and construct dwellings, offices and other buildings. Thankfully, the array of eco-conscious products keeps increasing, helping us make better choices for a new world.