Space cooling and heating is a common need in most inhabited areas. In Europe, the energy consumed for air conditioning is rising, and the situation could get worse in the near future due to the temperature increase in different regions worldwide. The increasing cooling need in buildings especially during the summer season is satisfied by the popular air conditioners, which often make use of refrigerants with high environmental impact and also lead to high electricity consumption. So, how can we reduce the energy demand for building cooling?
A new study comes from a research group based at the Politecnico di Torino (SMaLL) and the National Institute of Metrological Research (INRiM), who has proposed a device capable of generating a cooling load without the use of electricity: the research has been published in Science Advances*. Like more traditional cooling devices, this new technology also exploits the evaporation of a liquid. However, the key idea proposed by the Turin researchers is to use simple water and common salt instead of chemicals that are potentially harmful for the environment. The environmental impact of the new device is also reduced because it is based on passive phenomena, i.e. spontaneous processes such as capillarity or evaporation, instead of on pumps and compressors that require energy and maintenance.
“Cooling by water evaporation has always been known. As an example, Nature makes use of sweat evaporation from the skin to cool down our body. However, this strategy is effective as long as air is not saturated with water vapour. Our idea was to come up with a low-cost technology capable to maximize the cooling effect regardless of the external water vapour conditions. Instead of being exposed to air, pure water is in contact with an impermeable membrane that keeps separated from a highly concentrated salty solution. The membrane can be imagined as a porous sieve with pore size in the order of one millionth of a meter. Owing to its water-repellent properties, our membrane liquid water does not pass through the membrane, whereas its vapour does. In this way, the fresh and salt water do not mix, while a constant water vapour flux occurs from one end of the membrane to the other. As a result, pure water gets cooled, with this effect being further amplified thanks to the presence of different evaporation stages. Clearly, the salty water concentration will constantly decrease and the cooling effect will diminish over time; however, the difference in salinity between the two solutions can be continuously – and sustainably – restored using solar energy, as also demonstrated in another recent study from our group**”, explains Matteo Alberghini, PhD student of the Energy Department of the Politecnico di Torino and first author of the research.
The interesting feature of the suggested device consists in its modular design made of cooling units, a few centimetres thick each, that can be stacked in series to increase the cooling effect in series, as happens with common batteries. In this way it is possible to finely tune the cooling power according to individual needs, possibly reaching cooling capacity comparable to those typically necessary for domestic use. Furthermore, water and salt do not need pumps or other auxiliaries to be transported within the device. On the contrary, it “moves” spontaneously thanks to capillary effects of some components which, like in kitchen paper, are capable of absorbing and transporting water also against gravity.
“Other technologies for passive cooling are also being tested in various labs and research centres worldwide, such as those based on infrared heat dissipation into the outer space – also known as radiative passive cooling. Those approaches, although promising and suitable for some applications, also present major limitations: the principle on which they are based may be ineffective in tropical climates and in general on very humid days, when, however, the need for conditioning would still be high; moreover, there is a theoretical limit for the maximum cooling power. Our passive prototype, based instead on evaporative cooling between two aqueous solutions with different salinities, could overcome this limit, creating a useful effect independent of external humidity. Moreover, we could obtain an even higher cooling capacity in the future by increasing the concentration of the saline solution or by resorting to a more sophisticated modular design of the device” commented the researchers.
Also due to the simplicity of the device assembly and the required materials, a rather low production cost can be envisioned, in the order of a few euros for each cooling stage. As such, the device could be ideal for installations in rural areas, where the possible lack of well-trained technicians can make operation and maintenance of traditional cooling systems difficult. Interesting applications can also be envisioned in regions with large availability in water with high saline concentration, such as coastal regions in the vicinity of large desalination plants or nearby salt marshes and salt mines.
As of now, the technology is not yet ready for an immediate commercial exploitation, and further developments (also subject to future funding or industrial partnerships) are necessary. In perspective, this technology could be used in combination with existing and more traditional cooling systems for effectively implementing energy saving strategies.
[*] Matteo Alberghini, Matteo Morciano, Matteo Fasano, Fabio Bertiglia, Vito Fernicola, Pietro Asinari, Eliodoro Chiavazzo. Multistage and passive cooling process driven by salinity difference, SCIENCE ADVANCES (2020), URL: https://advances.sciencemag.org/content/6/11/eaax5015
[**] Eliodoro Chiavazzo, Matteo Morciano, Francesca Viglino, Matteo Fasano, Pietro Asinari, Passive solar high-yield seawater desalination by modular and low-cost distillation, NATURE SUSTAINABILITY (2018), URL: https://www.nature.com/articles/s41893-018-0186-x
An international research group has analyzed the visual impact of PV facades on buildings which include crop cultivation. Architects, PV specialists and farmers were surveyed and the results showed broad acceptance of such projects. The ‘vertical farming’ survey generated suggestions for the design of productive facades. So here is Raising crops in PV facades of buildings by Emiliano Bellini.
The researchers conducted anonymous 10-minute, multiple-choice web surveys in English with 15 questions. The group also provided images of four variants of productive facade, with respondents asked to rate their architectural quality on a scale of one to five.
The questions addressed topics including the visual impact of PV modules and crops, preferences about the arrangement of PV modules and ease of operation for owners and workers. Around 80% of the 97 respondents were architects with the remainder engineers, PV specialists, productive facade experts, horticulturalists, solar facade professionals, consultants and other professionals.
The results indicated architects and designers gave low ratings to all four of the designs presented and rated the design of PV installation poor. However, respondents with experience in horticulture, farming and PV facades showed stronger acceptance of building-integrated productive facades. “All groups of experts agree that PFs have the most positive effect on the exterior facade design and have accordingly graded them with higher marks than the designs without PV and VF [vertical farming] systems,” the paper noted.
Concerns were expressed by almost all respondents about the logistics of crop cultivation and irrigation near electronic devices such as the vertical solar modules.
“Several comments recommended exploring more creative designs,” the researchers added.
The lowest rating – 2.84 – was given to a productive facade with only PV modules visible from the inside. The highest mark – 3.9 – was scored by the image in which only plants were visible.
Tips for developers
The study also generated recommendations for the improvement of productive facade prototypes. “It should be noted that the selection of elements for practical application cannot be made based on a single isolated PF element – the entire building should be considered, especially the aesthetic elements of the building envelope, such as composition, proportion, rhythm, transparency, scale, colors and materials,” the researchers stated.
The study’s authors recommended the installation of the PV systems on north and south-facing facades, with ceiling level a preferable location.
Tilt angles of less than 20 degrees were suggested as a better aesthetic solution which would also avoid reflection onto neighboring buildings. “However, a well-designed integration of the PV modules with the planter of the above storey provides additional advantages – it improves the quality of indoor daylight and obstructs the view from inside to a lesser degree,” the study stated.
The researchers added copper indium gallium selenide (CIGS) panels were preferred to crystalline silicon modules, due to their more homogeneous structure.
Emiliano joined pv magazine in March 2017. He has been reporting on solar and renewable energy since 2009.
Buildings kill millions of birds. Here’s how to reduce the toll
As high-rise cities grow upwards and outwards, increasing numbers of birds die by crashing into glass buildings each year. And of course, many others break beaks, wings and legs or suffer other physical harm. But we can help eradicate the danger by good design.
Most research into building-related bird deaths has been done in the United States and Canada, where cities such as Toronto and New York City are located on bird migration paths. In New York City alone, the death toll from flying into buildings is about 200,000 birds a year.
Across the US and Canada, bird populations have shrunk by about 3 billion since 1970. The causes include loss of habitat and urbanisation, pesticides and the effects of global warming, which reduces food sources.
And that’s where the problems start with high-rise buildings. Most of them are much taller than the height at which birds fly. In Melbourne, for example, Australia 108 is 316 metres, Eureka 300 metres, Aurora 270 metres and Rialto 251 metres. The list is growing as the city expands vertically.
The paradigm of high-rise gothams, New York City, has hundreds of skyscrapers, most with fully glass, reflective walls. One World Trade is 541 metres high, the 1931 Empire State is 381 metres (although not all glass) and even the city’s 100th-highest building, 712 Fifth Avenue, is 198 metres.
To add to the problems of this forest of glass the city requires buildings to provide rooftop green places. These attract roosting birds, which then launch off inside the canyons of reflective glass walls – often mistaking these for open sky or trees reflected from behind.
A problem of lighting and reflections
Most cities today contain predominantly glass buildings – about 60% of the external wall surface. These buildings do not rely on visible frames, as in the past, and have very limited or no openable windows (for human safety reasons). They are fully air-conditioned, of course.
Birds cannot recognise daylight reflections and glass does not appear to them to be solid. If it is clear they see it as the image beyond the glass. They can also be caught in building cul-de-sac courtyards – open spaces with closed ends are traps.
At night, the problem is light from buildings, which may disorientate birds. Birds are drawn to lights at night. Glass walls then simply act as targets.
Architectural elements like awnings, screens, grilles, shutters and verandas deter birds from hitting buildings. Opaque glass also provides a warning.
Birds see ultraviolet light, which humans cannot. Some manufacturers are now developing glass with patterns using a mixed UV wavelength range that alerts birds but has no effect on human sight.
New York City recently passed a bird-friendly law requiring all new buildings and building alterations (at least under 23 metres tall, where most fly) be designed so birds can recognise glass. Windows must be “fritted” using applied labels, dots, stripes and so on.
Combinations of methods are being used to scare or warn away birds from flying into glass walls. These range from dummy hawks (a natural enemy) and actual falcons and hawks, which scare birds, to balloons (like those used during the London Blitz in the second world war), scary noises and gas cannons … even other dead birds.
Researchers are using lasers to produce light ray disturbance in cities especially at night and on dark days.
Noise can be effective, although birds do acclimatise if the noises are produced full-time. However, noise used as a “sonic net” can effectively drown out bird chatter and that interference forces them to move on looking for quietness. The technology has been used at airports, for example.
A zen curtain developed in Brisbane has worked at the University of Queensland. This approach uses an open curtain of ropes strung on the side of buildings. These flutter in the breeze, making patterns and shadows on glass, which birds don’t like.
These zen curtains can also be used to make windows on a house safer for birds. However, such a device would take some doing for the huge structures of a metropolis.
More common, and best adopted at the design phase of a building, is to mark window glass so birds can see it. Just as we etch images on glass doors to alert people, we can apply a label or decal to a window as a warning to birds. Even using interior blinds semi-open will deter birds.
Birds make cities friendlier as part of the shared environment. We have a responsibility to provide safe flying and security from the effects of human habitation and construction, and we know how to achieve that.
This article has been updated to correct the figure for the estimated number of birds killed by the cats in the US to “up to 4 billion”, not 4 million.
At this year’s Light+Building trade fair, Siemens will showcase its vision for transforming today’s passive buildings into learning and adaptive environments that intelligently interact with people. The company’s focus at this year’s show is “Building the future today”, outlining the innovations that will make this possible. These include cloud-based technologies, digital planning, occupant-centric building automation and services. New solutions for smart electrical infrastructure that seamlessly connects to the Internet of Things (IoT) are also at the core of this transformation.
„Building the future today”: Siemens at Light+Building 2020 in hall 11, booth B56“Around 99 percent of today’s buildings are not smart. Digitalization has the power to transform buildings from silent and passive structures into living organisms that interact, learn from and adapt to the changing needs of occupants. This is a significant leap in the evolution of buildings where our technology plays a vital role,” said Cedrik Neike, Member of the Managing Board of Siemens AG and Chief Executive Officer of Siemens Smart Infrastructure. “This transformation is already becoming a reality. We expect to see the first entirely self-adaptive buildings in three to five years from now.”
Digital solutions for the entire building lifecycle
Globalization, urbanization, climate change, and demographics are changing the way people live and work. At the same time, digitalization is ubiquitous. With some 10 billion building devices already connected to the IoT, buildings are ready to leverage the potential of digitalization. People spend an estimated 90 percent of their lives indoors, so ensuring buildings meet the broad range of individuals’ needs is crucial. On one hand, smart buildings actively contribute to occupants’ enhanced productivity, wellbeing and comfort. For operators and owners, they help them collect and analyze data to create actionable insights, boosting buildings’ performance and therefore revenue.Siemens will showcase the smart buildings suite of IoT enabled devices, applications and services. At the core of the suite is the “Building Twin” application, which will be on display at the booth. It provides a fully digital representation of a physical building, merging static as well as dynamic data from multiple sources into a 3D virtual model. With real-time understanding of how a building is performing, operators can immediately make adjustments to boost efficiency as well as extract data to improve the design of future buildings. One of the new IoT-enabled applications is “Building Operator”, which allows remote monitoring, operation and maintenance of buildings. Available as Software as a Service (SaaS), it provides real-time building data as the basis for predictive and corrective maintenance.
Smart electrical infrastructure
Given that buildings account for more than 40 percent of electricity consumption in cities, building efficiency is crucial in the battle towards decarbonization. Electrical infrastructure lays the foundation for safe, reliable and efficient building operations, while delivering essential data for a holistic, cloud-based building management. This is made possible by communication-capable low-voltage products, power distribution boards and busbar trunking systems that enable the measurement and wireless transmission of energy and status data. To illustrate this, Siemens will exhibit a unique end-to-end solution for cloud-based power monitoring in buildings. Electrical installations can now be supplemented with digital metering without additional space requirements or wiring outlay. This makes it easy for electrical installers to start using digitalization to their benefit. With “Powermanager”, a power monitoring software, now fully integrated into the Desigo CC building management platform, all building and energy data can be managed, monitored and analyzed from one single platform.Siemens will also display its electromobility ecosystem, including battery storage and charging systems for residential buildings. In a parallel show, “Intersec Building 2020”, in hall 9.1, booth B50, the company will exhibit integrated and networked systems for safety and fire protection.
Sidewalk Labs prototype would be the world’s tallest wood-frame building. That is good to know but Reach for the Sky—Wood Frame Building Will Be 35 Storiesby Roopinder Tara posted on January 28, 2020, could seriously be envisaged if the world were to be limited to the northern as well as to the Equatorial zones where forestry abounds. Transporting however wooden building materials from and/or to any other area of the world would probably cancel any significant environmental benefits.
Given that wood is flammable and biodegradable, it may never have been an ideal building material. We have steel for that. However, in many parts of the world, wood is available in abundance, so it is pressed into service for our buildings. Wood framing is common in North America for residential buildings but less so for commercial buildings. Wood framing has largely been unheard for use in high rises—until today, when plans of a 35-story wood frame skyscraper, part of Sidewalk Labs development project in Toronto, popped into my inbox.
No building this tall has ever been built with a wood frame. It’s not even close. The current tallest wood-frame building is Norway’s 85.4m-tall Mjøstårnet. The second tallest is the 53m-tall Brock Commons Tallwood House in Vancouver. Both buildings are 18 stories.
Sidewalk Labs has a digital model, a proof of concept it calls the PMX Tower (Proto-Model X). There’s a lot to be worked out when making a wooden building this tall.
The PMX plans do not call for using plain, ordinary wood, but “mass wood,” or a wood-mostly material that when glued together is called “glulam” and is used for ultra-long beams and columns. It is called nail laminated timber (NLT), and the plywood-like cross-laminated timber (CLT), which is used for floor and roof decks as well as bearing walls. Mass wood can be made fire resistant with the addition of chemical fire retardants, though this certainly makes the material less green. Mass wood’s manufacturers claim that the carbon emissions produced from making it are far less than the emissions created in making of steel or concrete—though cutting down trees is hardly green. Mass wood looks better than steel or concrete. We cannot argue with that. Plans for PMX call for a wooden external skeleton. (Image courtesy of medium.com.)
With a much lower strength-to-weight ratio than steel, wood of any type poses special challenges. But with a Sidewalk Labs team dead set on sustainability, a steel frame and concrete curtain walls were a nonstarter. Still, duplicating the same type of frame used in steel and concrete construction with wood would have resulted in ridiculously massive structural elements. A “timber core” design would have walls 5-feet thick. Not only would walls this thick require too many trees, they would also be difficult to manufacture and ship. In addition, they would take up too much floor space. PMX is going with a design that uses a wooden “exoskeleton” consisting of diagonal bracing and vertical columns on the outside of the building that support a 10-inch-thick “lean wood core.”
The BIM was done with Autodesk Revit and is hosted on BIM 360, a cloud-based construction management application.
A Counterintuitive Counterweight
A concrete and steel tower would be 2.5 times as heavy as a wooden skyscraper. But whereas light weight is an asset in aircraft and rockets that seek to escape gravity, it can be a liability in buildings that need to stay put. Preliminary analysis showed the 35-story wood frame construction had as much deflection in the wind as a 40- to 50-story building constructed with a steel frame.
The PMX team found that it had to allow a lot of steel into the design—in the form of a 70-ton steel weight, part of a system that is designed to dampen vibration.
While it may seem counterintuitive—perhaps even dangerous—to have massive weight on top of a building, that is exactly what civil engineers may order for a tall building that is swaying too much or is expected to do so. Tall buildings can have deflections of several feet on their top floors—unsettling and even sickening their occupants. A tuned mass dampener (TMD) system, can be designed in or retrofitted. A TMD with a precisely calculated amount of mass made of concrete, steel, lead or other dense material stays still due to its own inertia when a tall building initially bends— as a result of the ground shaking or a gust of wind. Dampeners attached to the mass absorb the energy and act to limit the number of oscillations.
TMD systems have been around for some time, but the increase in super tall and very thin tall buildings has made them even more sought after. Shanghai, New York and Dubai have several buildings with TMDs. Taiwan’s Taipei 101 tower uses a system that makes its TMD, with a suspended golden ball, a visible design feature.
The Canadian National Tower, at one time the tallest structure in North America at 102m, also in Toronto’s downtown, has two doughnut-shaped steel rings, one at 488m and the other at 503m—each weighing 9 metric tons—that serve as TMDs. They are tuned to the 2nd and 4th mode shape of the tower, while the 1st and 3rd mode are controlled by the prestressed concrete and don’t require additional damping.
Boston’s John Hancock Tower had two 30-ton sliding dampers installed retroactively that were designed to reduce the building’s sway by 40 percent to 50 percent.
TMDs can take several forms, including sliding, rolling or swinging weights.
Not Your Parents Prefab
As much as possible, the PMX designer sought to make the building off-site in parts, and then assemble the parts on-site. This is the long sought-after advantage manufacturing has enjoyed, while construction has lagged behind. PMX is making staircases, floor panels, walls, and kitchen and bathroom “pods” standard and assembled in assembly lines, transporting them to the waterfront site on trucks, and then snapping them together … like Legos, according to this article. These “cassettes,” as the sub-assemblies are called, will be made in 25 steps, with each step estimated to take 25 minutes. It is assembly line techniques at work, rather than the painstaking, laborious, material wasting current practice of laying floors, pouring concrete, joining gigantic steel members, and so on, that is the common conventional construction trade practice.
In addition to busting out of age-old construction practices, the PMX also hopes to bust out of the lowly status that prefab construction can’t seem to shake, like a screw-top wine. The plan’s exoskeleton can be draped in any manner of dress and color—a far cry from the welcome to middle-class, prefab homes in cookie cutter neighborhoods that gave prefab a low-class status.
Sidewalk Labs has a $1.3 billion project to develop Quayside, a 12-acre area in Toronto on the banks of Lake Ontario. Sidewalk Labs, part of Alphabet Inc., which also owns Google, was formed to create communities “from the Internet up.” When complete, Sidewalk Toronto would potentially bring 44,000 jobs, many of them tech jobs, to Toronto’s downtown. It was to be a test bed for technology close to city scale, including roads especially designed for autonomous vehicles. But the proposal may have represented too much technology for Toronto’s residents. Sidewalk Labs plans to pool and make public “urban data” gathered from those who were in Sidewalk Toronto. The city will be voting on whether to move forward with the Sidewalk Labs proposal.
The world of fungi has attracted a lot of interest and seems to be becoming very fashionable of late. A new exhibition at Somerset House in London, for example, is dedicated to “the remarkable mushroom”. No surprise: we’re being promised that mushrooms may be the key to a sustainable future in fields as diverse as fashion, toxic spill clean ups, mental health and construction. It’s in this last field that my own interests lie.
Climate change is the fundamental design problem of our time: buildings are hugely complicit in the crisis. Together, buildings and construction contribute 39% of the world’s carbon footprint. Energy used to heat, cool and light buildings accounts for 28% of these emissions: households are the biggest emitter of greenhouse gases since 2015, accounting for a quarter of total UK greenhouse gas emissions in 2017.
The remaining 11% of buildings’ carbon emissions consists of those associated with construction and building materials. The UK construction industry, for example, uses around 400 million tonnes of materials each year and approximately 100 million tonnes become waste. Cement alone is responsible for a whopping 8% of global CO₂ emissions. Compare this to the much maligned global aviation industry, which emits 2% of all human-induced CO₂ emissions. Buildings and, by association, the construction industry, are profoundly responsible for climate change.
There is evidently a real need for the construction industry to reduce the impact of its material and energy use and to take part in the transition towards a more sustainable economy by researching and using alternative materials. This is not an absurd ask: such materials already exist.
And yes, one such material happens to be derived from fungi: mycelium composites. This material is created by growing mycelium – the thread-like main body of a fungus – of certain mushroom-producing fungi on agricultural wastes.
Mycelium are mainly composed of a web of filaments called “hyphae”, which acts as a natural binder, growing to form huge networks called “mycelia”. These grow by digesting nutrients from agricultural waste while bonding to the surface of the waste material, acting as a natural self-assembling glue. The entire process uses biological growth rather than expensive, energy intensive manufacturing processes.
Mycelium materials offer an exciting opportunity to upcycle agricultural waste into a low-cost, sustainable and biodegradable material alternative. This could potentially reduce the use of fossil fuel dependant materials. The materials are low-density, making them very light compared to other materials used in construction. They also have excellent thermal and fire resistant properties.
To date, mycelium materials have been used in a number of inventive ways in building projects. One particular company of note is The Living, a New York based architectural firm which designed an organic mycelium tower known as “Hy-Fi” in the courtyard of MoMA’s PS1 space in midtown Manhattan. Designed as part of MoMA’s Young Architects Program, the structure illustrates the potential of this biodegradable material, in this case made from farm waste and cultured fungus grown in brick-shaped moulds.
Another project of note is MycoTree, a spatial branching structure made out of load-bearing mycelium components. This research project was constructed as the centrepiece for the “Beyond Mining – Urban Growth” exhibition at the Seoul Biennale of Architecture and Urbanism 2017 in Seoul, Korea. The project illustrates a provocative vision of how building materials made from mycelium can achieve structural stability. This opens up the possibility of using the material structurally and safely within the construction industry.
I am investigating the development of mycelium materials using locally sourced materials such as wheat straw. Wheat straw is a cheap and abundant source of waste in the Yorkshire region, so would be a fantastic raw material for construction. My main objective is to develop a material for use in non-load bearing applications, such as internal wall construction and façade cladding. The material displays similar structural properties to those of natural materials like wood.
The development of mycelium materials from locally sourced agricultural waste could reduce the construction industry’s reliance on traditional materials, which could improve its carbon footprint. Mycelium composite manufacturing also has the potential to be a major driving force in developing new bioindustries in rural areas, generating sustainable economic growth while creating new jobs.
The construction industry is faced with a choice. It must be revolutionised. If we carry with business as usual, we must live with the potentially catastrophic consequences of climate change.
New research by AESG outlines key Urban Resilience design principles and best-practices and provides insight to enable cities to better mitigate the impact of climate change.
68% of the world’s population is expected to live in urban areas by 2050
There is a proven correlation between increases in urbanization and climate change
Therefore, it is imperative for governments, city planners and developers to future-proof their cities by investing in urban resilience programs
With 68% of the world’s population expected to live in urban areas by 2050 and a proven correlation between increases in urbanization and climate change, it is imperative for governments, city planners and developers to future-proof their cities by investing in urban resilience programs. AESG, an international Specialist Consulting, Engineering and Advisory firm, has released a new research article which presents clear guidance on urban resilience concepts and best practices. The company intends for this report, titled ‘Urban resilience: A look into global climate change impacts and possible design mitigation’, to aid governments, city planners, engineers, architects and developers in building resilient cities that can better tackle the urban challenges resulting from climate change.
Saeed Al Abbar, Managing Director at AESG advocates the need for a concerted effort by these stakeholders to mitigate the climate change impact on cities through better urban planning. “While the effects of climate change can be detrimental, a large majority of these can be alleviated by strengthening interdependent infrastructure systems and ensuring resilience on infrastructure, policy and economic basis,” he said.
“Building resilience in cities is essential to not only make populations and infrastructure less susceptible to damage and loss but to also make them more agile to the unpredictable nature of climate change impacts. We are at a pivotal moment in human history, and the actions we take today will bear a profound impact on the security and quality of life, of us, and our future generations,” he added.
The report, developed by AESG’s qualified team of sustainability, environmental and planning experts, stresses that achieving urban resilience necessitates planning a city at a macro-level, understanding interdependencies of its systems and implementing solutions to mitigate the anticipated risks. In addition to reporting the key climate-related threats that cities today face, the article expertly analyses the innovative locational, structural and regulatory approaches being implemented globally to address a myriad of urban challenges.
Briefly summarizing the insight and guidance detailed in these best practices, Al Abbar said. “For city and municipal governments, resilience implies planning development, providing safe and affordable infrastructure and services, regulating building design and construction, regulating hazardous activities, influencing land availability and construction requirements, encouraging and supporting household and community actions to reduce risk, and finally, putting in place effective disaster early warning, preparedness, and response systems.”
Egypt Today.com posted an article dated August 7, 2019, that brings to light an unusual construction project concept. It combines building towers with an agricultural development project. The project concept if multiplied in numbers will certainly be increasing Egypt’s limited area of farm land that is confined to the Nile Valley and Delta, with a few oases and some arable land in the Sinai peninsula.
CAIRO – 7 August 2019: Italian Architect Stefano Boeri spoke to CNN about Africa’s first vertical forests that will be built in Egypt’s New Administrative Capital (NAC), which is still under construction and is 30 miles east of Cairo.
Each of the three cube-shaped blocks will be 30 meters high and will house seven floors, 350 trees, and 14,000 shrubs of over 100 species. “Each tower of trees aims to provide its human residents with an average of two trees, eight shrubs and 40 bushes each,” as reported by CNN.
Boeri has been designing the blocks in collaboration with Egyptian designer Shimaa Shalash and Italian landscape architect Laura Gatti. Shalash told CNN that execution of the project is set to start in 2020 and finish in 2 years. One of the three buildings will be an energy self-sufficient hotel, while the other two will contain residential apartments.
“Each apartment will have its own balcony with a range of plant species suited to the local climate, planted at various heights and to bloom at different times to provide a lush appearance year round. Plants at every level will provide natural shading and improve the surrounding air quality by absorbing an estimated 7 tons of carbon dioxide and producing 8 tons of oxygen per year,” CNN reported.
Shalash and colleagues explained to CNN that the project – owned by a private real estate developer – is part of a bigger plan to introduce “thousands of green flat roofs and a system of “green corridors” in the city.”
According to an expert in sustainable design, how to keep buildings cool without air conditioning, is by no mean as impossible as it may sound.
The warmer it gets, the more people crank up the air conditioning (AC). In fact, AC is booming in nations across the world: it’s predicted that around two-thirds of the world’s households could have an air conditioner by 2050, and the demand for energy to cool buildings will triple.
But unless the energy comes from renewable sources, all that added demand will generate more greenhouse gas emissions, which contribute to global warming – and of course, to hotter summers. It’s a vicious cycle – but buildings can be designed to keep the heat out, without contributing to climate change.
1. Windows and shading
Opening windows is a common way people try to cool buildings – but air inside will be just as hot as outside. In fact, the simplest way to keep the heat out is with good insulation and well-positioned windows. Since the sun is high in summer, external horizontal shading such as overhangs and louvres are really effective.
East and west-facing windows are more difficult to shade. Blinds and curtains are not great as they block the view and daylight, and if they are positioned inside the window, the heat actually enters the building. For this reason, external shutters – like those often seen on old buildings in France and Italy – are preferable.
2. Paints and glazes
It’s now common for roofs to be painted with special pigments that are designed to reflect solar radiation – not just in the visible range of light, but also the infrared spectrum. These can reduce surface temperatures by more than 10°C, compared to conventional paint. High-performance solar glazing on windows also help, with coatings that are “spectrally selective”, which means they keep the sun’s heat outside but let daylight in.
There’s also photochromic glazing, that changes transparency depending on the intensity of the light (like some sunglasses) and thermochromic glazing, that becomes darker when it is hot, which can also help. Even thermochromic paints, which absorb light and heat when it’s cold, and reflect it when it’s hot, are being developed.
3. Building materials
Buildings which are made of stone, bricks or concrete, or embedded into the ground, can feel cooler thanks to the high “thermal mass” of these materials – that is, their ability to absorb and release heat slowly, thereby smoothing temperatures over time, making daytime cooler and night time warmer. If you have ever visited a stone church in the middle of the Italian summer, you will probably have felt this cooling effect in action.
Unfortunately, modern buildings often have little thermal mass, or materials with high thermal mass are covered with plasterboard and carpets. Timber is also increasingly used in construction, and while making buildings out of timber generally has lower environmental impacts, its thermal mass is horrendous.
4. Hybrid and phase change materials
While concrete has a high thermal mass, it’s extremely energy intensive to produce: 8% to 10% of the world’s carbon dioxide (CO₂) emissions come from cement. Alternatives such as hybrid systems, composed of timber together with concrete, are increasingly being used in construction, and can help reduce environmental impacts, while also providing the desired thermal mass.
Another, more exciting solution is phase change materials (PCMs). These remarkable materials are able to store or release energy in the form of latent heat, as the material changes phase. So when it’s cold, the substance changes to solid phase (it freezes) and releases heat. When it becomes liquid again, the material absorbs heat, providing a cooling effect.
PCMs can have even greater thermal mass than stones or concrete – research has found that these materials can reduce the internal temperatures by up to 5°C. If added to a building with AC, they can reduce electricity consumption from cooling by 30%.
PCMs have been hailed as a very promising technology by researchers, and are available commercially – often in ceiling tiles and wall panels. Alas, the manufacture of PCMs is still energy intensive. But some PCMs can cause a quarter of the CO₂ emissions that others do, so choosing the correct product is key. And manufacturing processes should become more efficient over time, making PCMs increasingly worthwhile.
5. Water evaporation
Water absorbs heat and evaporates, and as it rises, it pushes cooler air downwards. This simple phenomenon has led to the development of cooling systems, which make use of water and natural ventilation to reduce the temperature indoors. Techniques used to evaporate water include using sprayers, atomizing nozzles (to create a mist), wet pads or porous materials, such as ceramic evaporators filled with water.
The water can be evaporated in towers, wind catchers or double skin walls – any feature which creates a channel where hot air and water vapour can rise, while cool air sinks. Such systems can be really effective, as long as the weather is relatively dry and the system is controlled carefully – temperatures as low as 14°C to 16°C have been reported in several buildings.
But before we get too enthusiastic about all these new technologies, let’s go back to basics. A simple way to ensure AC doesn’t contribute to global warming is to power it with renewables – in the hot weather, solar energy seems the obvious choice, but it takes money and space. The fact remains, buildings can no longer be designed without considering how they respond to heat – glass skyscrapers, for example, should become obsolete. Instead, well insulated roofs and walls are crucial in very hot weather.
Everything that uses electricity in buildings should be as energy efficient as possible. Lighting, computers, dishwashers and televisions all use electricity, and inevitably produce some heat – these should be switched off when not in use. That way, we can all keep as cool as possible, all summer long.
Actions by individuals and businesses, such as improving energy efficiency in the home or office, make a difference.
The role of technology in keeping climate catastrophe at bay is becoming ever more critical. The resurgence of protests around the world such as the civil havoc wreaked by Extinction Rebellion or the school strikes begun by Swedish schoolgirl Greta Thunberg has renewed pressure on governments to “do something”, no matter how unrealistic or economically ruinous.
The individual and political solutions usually meant by “doing something” are not as straightforward as they sound and may actually create more difficulties than they solve. Actions by individuals and businesses, such as improving energy efficiency in the home or office, make a difference, but this is still a drop in the ocean when put up against the output of the world’s biggest emitters of greenhouse gases. They are also a bit hit-and-miss. Many of us are happy to do our bit of recycling or to stop the tap running while we brush our teeth, but how many of us are prepared never to fly again or to take up a vegan diet?
Similarly, swingeing political solutions such as carbon and fuel taxes can jolly things along, but such taxes inevitably hit the poor hardest and contribute to their own political unrest, as seen with the Yellow Vest movement in France, which could backfire by encouraging the election of more climate-sceptic leaders such as Donald Trump.
Technology presents only opportunities Yet where individual and political solutions pose their own problems, the technological approach presents only opportunities. The growing recognition of the essential role played by green technology is highlighted by the fact that the World Green Economy Summit held in Dubai last year included a discussion on the role of technology in the green economy, this year it will be the summit’s overarching theme.
One example of the win-win nature of technological solutions to green issues is renewable energy. In its early days, renewables were seen by many as nothing more than a way for governments to spend taxpayers’ money on switching to more expensive energy. But we hung in there and the fruits are beginning to show. Prices of renewables, particularly solar, are through better technology being brought to a point where not only do they no longer require public subsidy, but turn a profit enough that they become an attractive business proposition.
Much still to be done Still, despite renewable power having accounted for 70 percent of net additions to global power generating capacity in 2017, greenhouse gas emissions edged higher that year nonetheless, showing there is still much work to be done. The main laggards were the heating, cooling and transport sectors, which account for about 80 percent of global energy demand.
This shows that although technological breakthroughs in areas such as renewable energy can have a win-win impact – reduced emissions and cheaper energy – the road ahead isn’t easy. For example, if there is a greater take-up of electric cars this might cause oil prices to fall, which in turn could increase demand from the aviation sector that would push up emissions.
Despite advances in green technology such as the smart grid, electric vehicles, bioplastics, carbon capture and storage, green computers and green packaging, some critics insist that these advances are not nearly enough. They say that although we have been led by some of the modern world’s amazing inventions into believing that technology can achieve anything that simply isn’t true. They contend that future advances in green technology cannot be blindly relied upon to save the planet, and that essential breakthroughs such as improved battery efficiency in electric vehicles may still be a long way off.
Technology predicted to potentially cut emissions by 64 percent by 2050 But if there are problems with green technology, they are considerably less than those created by a purely political approach, which will inevitably lead to punitive, and polarising, taxes. Governments would do better to ease the path for innovative firms and startups through funding and supportive legislation so they can find the myriad solutions that will be needed to meet or go beyond the carbon targets of the Paris Agreement. ING in a report issued last year predicted that such an approach could result in a 64 percent decrease in greenhouse gas emissions by 2050.
To conclude, while the political pressure intensifies to enact all sorts of rash and damaging ecological measures, it is best to keep our heads and do all we can to back and push forward the technological innovations that may not just combat climate change, but do so while strengthening the global economy.
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