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.
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[*] 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
Oman’s Ministry of Technology and Communications (MTC) has committed to a memorandum of cooperation (MoC) with BankDhofar at the Sas Center for the 4th Industrial Revolution (4IR), in order to manage a technology innovation lab at the center.
The MoC was reportedly signed by Dr Salim bin Sultan Al Ruzaiqi, CEO at MTC, and Abdul Hakeem Omar Al-Ojaili, CEO at BankDhofar.
The innovation lab has been established to help students and local Fintech startups, as they focus on developing innovative financial technology products and services.
“The Ministry has launched the SAS Center for the 4th Industrial Revolution to keep pace with the current developments in the ICT sector. Signing this MoC with BankDhofar reflects the significant role of the private sector in supporting this dynamic sector and the Omani youth initiatives in entrepreneurship.”
He added that through this cooperation, they aim to create an encouraging environment that can help develop useful Fintech solutions, which could become part of the 4th IR technologies.
He also said the project aims to encourage and support Oman’s private sector organizations to continue to empower the nation’s emerging technology fields.
“The innovative lab at Sas Centre for 4th Industrial Revolution serves our vision of contributing to such projects of national value, and it also contributes to the development of the Fintech field in general.”
He continued:
“We are in the midst of the 4th Industrial Revolution where the banking sector has to seize the opportunity and take part, supporting the youth and encouraging them to become effective in a field which will positively contribute to the national economic growth in the future.”
MTC and BankDhofar will work cooperatively to establish, host, and manage the innovation lab. They will provide mentorship and training for Omani students, staff, local startups and Fintech firms.
In December 2019, Bank Muscat, the leading financial services provider in the Sultanate, revealed that the Central Bank of Oman had approved the institution’s request to establish a $100 million (appr. OMR38.5 million) nationwide, strategic Fintech investment program.
The investment program is reportedly part of Bank Muscat’s strategic growth initiative.Sponsored Links by DQ Promote
Around 3,300 years ago, the port city of Ugarit was a vibrant urban centre, located strategically on the overland network linking Egypt with Asia Minor and on the route between Persia and India in the east and Greece and Cyprus in the west. The city’s origins date back to 3000BC and the first alphabet and alphabetic writing system are believed to have developed there in the 14th century BC.
Today Ugarit is a Bronze Age archaeological site in northwest Syria, first excavated in 1929. It can tell us a huge amount about the past, but Ugarit is also a place in its own right. The conservation of the site needs to help us understand the site’s history, as well as preserving and restoring what remains. Our work on virtual reality and reconstruction can meet both these goals.
Figure 1: The location of Ugarit and its historic links. Google Map
Although only 30% of Ugarit has been excavated, the discovered areas give clues about the organisation of the city. The buildings include royal palaces, large houses, tombs, sanctuaries, public buildings and temples. Ugarit’s golden age was between the 14th and 12th century BC, and the excavated ruins show that interesting political, social and economic evolution took place in the city.
The royal area shows evidence of a developed political system, with complex defensive architecture and a well-structured palace. Domestic areas reveal important information about the Ugaritic people’s everyday life and their veneration of the dead. However, the structures are in a ruined condition and some are deteriorating, thanks to being exposed for more than 90 years with only minimal maintenance and repair work.
Virtual conservation
A shift toward using virtual technologies as preservation methods to document historic sites and provide educational opportunities has taken place in recent years. This prevents misguided architectural conservation, which can damage a site.
Augmented reality can project reconstructions onto archaeological ruins, such as at the medieval village of Ename in Belgium. Elsewhere, virtual reconstruction has produced 3D textured models, including of the “Sala dello Scrutinio” at the Doges’ Palace in Venice.
Figure 2: A map of the city of Ugarit showing the excavated areas and the sacred route between the Royal Palace and the Temple. Latakia National Museum, Syria
We have used computer-aided design modelling to test out conservation options for Ugarit and to investigate the effects of possible conservation interventions on the ruins. This led to changes in design concepts and materials to better fit the aims of the conservation.
Preserving a sacred route
Excavations have revealed a key sacred route that linked the Royal Palace with the main Temple of Baal and passed through public areas of Ugarit. Researchers believe that the king followed this sacred path to practice cult sacrifices at the temple.
The route contains important tangible elements, such as the remains of the palace, houses, and the temple, for example. But the conservation strategy also intends to reconstruct the intangible aspects of the route – the monumental fortifications, the scale of the temple, and the experience of walking the sacred path, all of which cannot be easily grasped from the remaining ruins.
Figure 3: Point A of the Sacred Route. The Author
Virtual reconstruction is an effective tool to assess these proposals and judge their ability to protect the ruins, as well as revealing intangible aspects, such as the atmosphere of a street, which are lost to time. We have developed virtual tours which create an opportunity for screen displays to be installed on the site before the actual proposal is implemented.
Figure 10: Virtual reconstruction of interventions proposed for Point C of the sacred route – the Temple of Baal. The author, Author provided
These virtual tours include an area of the site that historically featured a plaza and tavern. Here the conservation approach includes the creation of a social and entertaining hub. This will allow the urban environment of the plaza and the dim and cosy interior of the tavern to be restored.
The tours provide reliable evidence for the second stage of the conservation proposal, the design stage and community consultation. However, the political situation in Syria has put the consultation process on hold.
This political situation also means that it is not possible to visit Ugarit at the moment – a position shared by hundreds of archaeological sites around the world. So the virtual reconstructions serve another purpose: they allow those interested a glimpse of this fascinating city and provide an opportunity to raise awareness of the site’s cultural importance with an international audience.
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.
Architectural concerns
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 Bellini
Emiliano joined pv magazine in March 2017. He has been reporting on solar and renewable energy since 2009.
Approximately half of all jobs will be materially impacted by automation in the next 15-20 years, said professional services firm Accenture in a new report.
Meanwhile, 79 per cent of executives agree that work is shifting from roles to projects—challenging both the function and makeup of the workforce as we know it, said Tanushree Guha, managing director of Applied Intelligence and global lead for the Workforce Analytics practice at Accenture in the report titled “OCED Employment Outlook 2019: The Future of Work”.
As more and more employees look for different opportunities, many are not choosing permanent jobs. In 2018 alone, 56.7 million Americans freelanced, and it is predicted that by 2027, the majority of America’s workers will be freelance. Those choosing part-time work or even working for multiple employers at one time will need to be factored into evolving workforce models, says Guha.
“Advances in digital and automation have allowed organizations to gain efficiency and increase productivity. But adopting these technologies means that organizations must plan for their workforce—especially those at risk of being made redundant,” the report said.
As many as 40 percent of companies are already reporting that talent shortages are impacting their ability to adapt and innovate and this highlights the need for organizations to upskill, reskill and cross-skill existing workers, it added.
A new approach to workforce management
Strategic workforce planning (SWFP) helps organizations strike the right balance between external contractors and internal workforce, as well as the right blend of human and machine effort to drive the business forward.
By providing a holistic perspective of the current workforce, and existing as well as future gaps, workforce planning can help organizations assess forthcoming risks and identify quick wins to yield potential savings. This enables organizations to strategize their recruitment and reskilling plans well in advance, as well as ascertain the most advantageous size and workforce mix of the organization both in the short and long term, the article said.
For example, using HR transformation analytics, organizations are turning recruitment from what was traditionally often a process based on “gut-feel,” to one informed and backed by advanced data insights. This transformation enables businesses to find the right people at the right time with the most relevant skills from a larger pool of applicants, whilst saving on time and money.
According to Guha, SWFP helps companies to be in a future-ready state, by enabling them to:
• Have a good hold of the current workforce scenario • Be well informed of possible future workforce gaps, facilitating them to strategize gap fulfilment and avoid the probable revenue losses due to those gaps • Devise a comprehensive action plan on efficiently utilizing the various workforce types to drive maximum productivity • Be well aware of the overtime changes in workforce dynamics and reasons for those changes • Design and implement optimal reskilling strategies in line with the changing requirements, at the same time as providing optimal career pathways to their workforce. – TradeArabia News Service
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.
But rampant global urbanisation is putting the reliance on glass buildings front-of-stage as an “unnatural” cause of bird deaths, and the problem is growing exponentially.
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.
Reflections of trees and sky lure birds into flying straight into buildings. Frank L Junior/Shutterstock
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.
White-throated Sparrows collected in a University of Michigan-led study of birds killed by flying into buildings lit up at night in Chicago and Cleveland. Roger Hart, University of Michigan/Futurity, CC BY
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.
Qatar-based Industrial Solutions leader ‘Nehmeh’ has organised the annual Mega Industrial Expo 2020 showcasing a range of the world’s leading brands in construction solutions,
Visitors during the annual Mega Industrial Expo 2020.
The two-day event was held on February 4 and 5 at a five-star hotel in Doha where Nehmeh showcased power tools, ventilation systems, light construction tools and machinery with a focus on concrete machinery along with demonstrations to let guests have a first-hand product experience of the machines and its applications.
An important part of the event was the launch of the Qatar’s first locally manufactured ‘Roof Top Package Unit’ by Nehmeh Air Conditioners and introduction of Belgium based ‘Beton Trowel’ brand renowned for Concrete & Compaction Equipment.
The event also featured key note address by experts from Beton Trowel, Nehmeh Air Conditioners and Makita over the two days. ‘Nehmeh App’ the region’s first industrial solutions mobile app was highlighted to guests at the expo. Nehmeh, one of the leading industrial solutions providers in the GCC, represents world class brands which are leaders in their respective categories.
For over 65 years, tens of thousands of people depend on reliable industrial performance solutions by Nehmeh. This mega event succeeded in attracting visitors including retail partners, suppliers, end-users and others related to the construction industry.
Visitors also included managers from Qatar looking for solutions to improve their efficiency and productivity on sites. Brands participating at the expo were Makita, Nehmeh Air Conditioners, Stampa, SDMO, Beton Trowel, Sofy, Portacool, Koshin, Awelco, Dr. Schulze among many more. Demonstrations were held on specially prepared areas showcasing tools, equipment and machinery. Expert professionals from Singapore, Germany and Belgium presented to the audience new introductions and technologies along with an informative Q & A session.
“Nehmeh range of Industrial Solutions cover major solutions required for the Qatari construction market. This concept event has been developed keeping in mind the requirements of our customers and I am glad to say that the event has been well received by the guests over the years,” said Emil A. Nehme, Chief Executive Officer at Nehmeh.
“With the support of our partners, we have the ability to cover major construction solutions as required here in Qatar. Witnessing the popularity of such an event, we are inclined to hold more such regular events as part of our calendar of activities,” he added.
‘The Nehmeh Corporate Catalogue 2020’ was launched during the event. Awards bestowed to various partners as tribute to their efforts and achievements. In addition, four lucky visitors also walked away with reward trips, gold coins and stay vouchers.
The GivePower non-profit founded by Tesla subsidiary SolarCity is supplying solar-powered desalination systems to some of the world’s neediest communities, backed by Tesla’s Powerwall battery technology. It is elaborated on in A new solar desalination system to address water scarcity by JEAN HAGGERTY.
FEBRUARY 6, 2020
One of GivePower’s desalination projects. Image: GivePower
GivePower is launching containerized, solar-powered water desalination and purification plants in Mombasa, Kenya and La Gonave, Haiti this quarter. Like GivePower’s debut solar-powered microgrid desalination plant, which went live in Kiunga, Kenya in 2018, these new projects will operate with Tesla’s powerwall battery storage technology.
At launch, both of the nonprofit’s new solar water farm projects will produce a maximum of 75,000 liters of water a day by coupling a 50-kW solar system with 120 kW-hrs of Tesla batteries; together this solar plus battery system will power two low-wattage, reverse osmosis desalination pumps that run simultaneously to ensure continuous operation.
When developing solar-powered desalination projects, pinning down the point at which the technology and the operating model make economic sense is key because the one of the biggest challenges with solar desalination is the amount of energy that it takes to desalinate sea water. Often, this outsized energy need means that a plant requires a larger solar array, which increases the cost of the project.
“We need to see that [these philanthropic] projects are economically viable – that these projects can continue to operate without ongoing funding from donors to keep the systems operational,” said Kyle Stephan, GivePower’s vice president of operations. In addition to building solar water farms, GivePower trains local technicians to operate the plants.
GivePower’s solar water farm systems cost just over $500,000, and they have a 20-year expected lifespan.
Commercial applications for GivePower’s solar water farm technology are not in the pipeline currently, according to Hayes Barnard, CEO of GivePower.
When it comes to developing commercial off-grid, solar-powered desalination systems for water-stressed communities, industry officials see solar microgrid players as particularly well placed to offer solutions.
Drought, saltwater intrusion and climate change are intensifying the need for solutions that use renewable energy to address water scarcity. Simultaneously, falling PV prices and energy storage innovations are making solar-powered desalination solutions more appealing.
So far, all of GivePower’s solar water farms are coastal well-based desalination plants. This is because 98% of the world’s water is in the ocean, and 73% of the world’s population live in coastal areas, where well water is susceptible to becoming brackish, Barnard noted. Additionally, off-coast solar desalination plants’ intake processes are expensive, and coastal well-based solar water farms do not stress underground aquifers.
For its project on La Gonave, which is off the coast of Port-au-Prince, GivePower is applying international building code seismic requirements for its solar water farm’s concrete foundation, and it is building a solar canopy that is capable of withstanding a category-four hurricane.
Initially, the nonprofit focused on providing solar-powered lighting to schools without electricity in the hope that this would open up educational opportunities for girls in developing countries. But quickly it became clear that helping communities achieve water security was key to addressing this issue because often girls were often missing school because their days were spent fetching water, according to Barnard, a GivePower co-founder. GivePower became an independent organization in 2016.
Last week GivePower’s solar-powered desalination technology received the UAE’s Global Water Impact Award for innovative small projects.
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.
Look closely—it’s made of wood. Exterior rendering of office and residential levels of Proto-Model X, Sidewalk Labs’ model of a timber frame destined for the Toronto waterfront. (Image courtesy of Michael Green Architecture and Gensler.)
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.
Engineering Wood
Looks like the real thing because it mostly is. Mass wood, an engineered structural material, can pass for normal wood—at a distance. (Image courtesy of HGA.)
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.
With the addition of a tuned mass damper, the PMX tower model stabilizes quicker. A gust of wind would make the towers bend to one side, then oscillate. Without losses, the tower would oscillate forever, but internal dampening would cause the structure to stop eventually. A tuned mass dampener would add more losses and make the tower stop swaying sooner. Note that in the model shown the dampener would only reduce swaying from right and left, but not back and forth. (Image courtesy of Gensler, Aspect.)
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.
Chicken Little would not approve. An 18-ft diameter, 660-metric ton steel sphere, which hangs like a pendulum and is visible between the 88th and 92nd floors of Taipei 101 in Taiwan, is a tuned mass damper (TMD) that reduces the swaying of tall buildings. (Image courtesy of Pinterest.)
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
Mechanical, electrical and plumbing equipment is embedded in a floor panel off-site in a factory. (Image courtesy of Integral.)
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 Toronto
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.
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Plans for PMX call for a wooden external skeleton. (Image courtesy of medium.com.)
