Archive for January, 2013


The Sea Serpent

Pelamis[1] is the name given to the technology which absorbs the energy generated by ocean waves and converts it into clean, green electricity.

Approximately 70% of Earth’s surface is covered by the oceans and it is natural that man should think of it as a permanent source of power when confronted with the perpetual movement of its waves.

Such were the thoughts of Dr Richard Yemm who in 1998 conceived a sea serpent which could adapt to sea moods, either softly gliding over them as a patient surfer waiting for his wave or shake, jump or throw itself furiously to its belly, as a bodyboarder not wanting to be untimely brought back to shore.

E.ON P2 Pelamis operating in Orkney July 2011Source: http://www.pelamiswave.com

As such, the serpent had to be designed to withstand all weather conditions and the secret was to discover how to best anchor it to the seabed. Satellite data was employed to study the topography and wave type on the sites where it was to be installed and buoys measured its length.

State-of-the-art computer simulations were run to model the serpent in the worst sea environment conditions and projections made within a 100-year period as well as tests in wave tanks to come up with the best design and suitable moorings with a high safety factor.

And so a Pelamis was conceived which generated electricity inside itself, so there is minimal need for onshore infrastructure and consequently environmental impact on the shoreline. Only a small building is necessary to house the electrical cables connection to the switchgear and transformers for the grid connection.

Since there is no need for man to access the serpent itself, maintenance operations can be run from a small quay or marina pontoon with some small storage amount available. Power is fed back from the ocean to the shore by underwater electrical cable and several Pelamis can be linked so as to share only one cable back to dry land.

PelamisSource: http://www.pelamiswave.com

Brightly coloured Pelamis are anchored to the seabed by a slack chain attached to its front facing the direction of the waves and let to meander as a weather-vane around the mooring.

They are manufactured in Scotland and the first commercial wave farm in the world was installed in the north of Portugal capable of generating electricity up to 2,000 homes.

 

By Silvia Pelham

[1] Pelamis plature, a species of sea snake - http://en.wikipedia.org/wiki/Pelamis

A Five-Leaf System member which prides itself on being totally integrated into its natural surroundings – an oasis by a salt lake, where time stops and man is closer to nature.

Egyptian desert

Source: The Adrère Amellal set into the rock – http://www.adrereamellal.net

The silent darkness of the western desert brings forth nature’s authenticity and the starry sky rules over the softly lit beeswax candled internal spaces carved out of the rock.

All forty rooms are hand-built and unique, blending into the landscape, doorways punched into the stone, open passageways to cool evening breezes, alcoves set into niches with small windows set back into thick walls.

A mixture of mud, sand and sun-dried salt make for the dressing of the walls and palm trunks cast the ceilings and local craftsmanship shines through exquisitely embroidered cloth.

Sitting on cushions spread over the desert sand or sitting on local crafted furniture in a grotto studded with salt crystals, one can savour organic food grown in the grounds and let time stand still.

desert dinner

Source: Dining in the desert – http://www.adrereamellal.net

Article by Silvia Pelham

Hot climates depend heavily on air conditioning systems, and it is well known that 70% of the power used at peak times can be traced back to them.

So anything which can be done to alter this figure can be seen as a means for cities to become more sustainable. One way is to focus on the source of this power; another is to find a controlled way of distributing it: thinking globally rather than individually.

The Pearl in Qatar is an island which was designed with this process in mind back in 2006. It has saved 40% to 60% of the required power over conventional systems. Less power in this case means fewer harmful emissions, less refrigerant leakage and also less noise pollution.

The Pearl

Source: The Pearl – Qatar – qatarmark.com

In order to accomplish this, one has to start by raising awareness of the potential available from optimising energy efficiency and conserving natural resources. In effect, it is back to the 3 E’s: environment – energy – economy.

And the end user should be the first to be considered, with everyone else involved being tracked back to the stakeholders. Without the end user engaged, no true partnership can be fostered with the community.

We are looking here at district cooling rather than individual units to cool each home. An expensive outlay at the outset of the project but well worth it when balanced against to benefits it brings to the end users.

Think of it: a utility service which provides chilled water through a centralised cooling plant to a pipe network, feeding residential, industrial and commercial buildings, increasing energy efficiency, reducing emissions, GHG[1] and ozone-destroying refrigerants.

In terms of cost benefits, the public-private partnership in Pearl Island was able to cut capital costs on equipment and also reduce control panels. The internal power distribution was minimised, the annual maintenance concentrated on one plant rather than several outlets and power consumption in individual buildings greatly reduced.

 AEC

Source: The Plant in Pearl Island – AEC – Architecture, Engineering, Construction   http://www.aeconline.ae

For the whole process to run smoothly, planning has to the foremost target from the outset: to reach a correct design process, choose adequate equipment and use the right resources.

In aesthetic terms, no more bulky A/C units on roofs, hanging from walls, cluttering balconies or clogging up yards. No noise and no vibration on building structures. No worries about operating and maintaining equipment.

All the end user has to do is to enjoy the added comfort, clean the unit filter when needed, pocket the savings and have the satisfaction of having contributed to reducing their impact on the environment.

Article by Silvia Pelham

[1] Green House Gas

If you are going to the Abu Dhabi Sustainability Week event, you must not miss a visit to Masdar City, less than 20km from downtown, famous as one of the lowest possible ecological footprint communities in the modern world.

It mirrors a city of the past, with high density, a pedestrian-friendly urban environment, awareness of local climate demands and in tune with its surroundings. The difference lies in its technology, backed up by research and development, pioneering best practices in sustainable urban planning and design.

Inhabitat

Source: “Inhabitat – design will save the world” – Lord Norman Foster’s zero emission masterplan for Masdar City

To design in hot climates, and especially in desert conditions, one has to expect temperatures at around the 60°Cmark but in Abu Dhabi´s main thoroughfare the air temperature can rise up to 70°C.

This isdue to the distance at which the main buildings are set apart from each other, the amount of external walling exposed to direct sunlight and the non-reflectance quality of building materials, all topped off by the radiant heat bounced back from tarmac roads.

What the architects[1] of Masdar City strived for was to bring together conditions which would provide comfort and quality of life for its inhabitants. In order to achieve this, they looked back at the way Arabian cities[2] were put together, and studied the way in which they could apply those good practices to their project.

The most important design criterion was the site itself and the climatic response needed to bring about this comfort, followed by form and massing and external enclosure.[3] These three elements accounted for 30% of the design decisions.

Internal configuration and what environmental systems to choose from took another 45% of the design considerations and the remaining 25% went on choosing how energy, water and materials were to be exploited.

In terms of the climatic response to the site, two points were crucial: orientation – positioning the buildings on a north easterly direction and close together for shading; and wind direction – how to capture the wind, how to get it to flow through the city and how to cool it. For this, computational fluid dynamic diagrams were drawn, based on wind catchers[4] such as those in Hyderabad.

fluid dynamics

Source: Computational Fluid Dynamics by Foster + Partners research

For cooling the air, natural ways were used whenever open spaces were crossed, taking in lessons from the past, illustrating that reduction could be achieved by shading arched walkways adjacent to buildings, tree-planting courtyards and seating areas close to decorative garden fountains, thus bringing street level temperatures in Masdar down from 55°C to 27°C.

The modern, man-made, way took in several features: running chilled water over louvers high up in towers, capturing hot air from the desert, concentrating beamed sunrays over oil containers, raising its temperature to 600°C, using oil drilling techniques to turn heat exchangers to cooling effect by getting turbines to come alive.

And all this was only possible because the whole city is a study ground for R&D at the cutting edge. The first University for Renewable Energy[5] in the world has been set up here and provided the first building on site inaugurated in October 2010.

And its characteristics are phenomenal: 100% on-site power generation; 60% back to grid; power usage 51% of UAE[6] norms; water usage 54% of UAE norms; all sewage and dry waste processed on site and recycled; treated water for irrigation and sanitation and geothermal pilot project progressing……

The site is a hub for future developments of environmental technologies and aims to lead the sector in this field. There are 12 pilot schemes being studied at the moment: the beam-down solar tower; a 10MW PV[7] farm; Fresnel CSP[8]; a parabolic trough; a geothermal test well; smart appliances and energy monitoring; a wind tower; a solar driven solar plant; a liquid deslocant dehumidification plant; an active sun tracking day-lighting system; a membrane bio-reactor and the PRT / FRT.[9]

The transport system below the pedestrian routes follows the main distribution arteries and follows a magnetic track – had the circulation been exterior and open to the elements, a GPS satellite system could have been employed.

Designed for the pedestrian, this transport network will be available throughout its 700 hectares. It is never more than a few minutes’ walk away for the user and will be complemented by light railway and an underground system, allowing its 40,000 residents to make full use of the space and the projected 50,000 daily commuters to easily get to and from the city.

a typical street

Source: Cross-section of a typical street by Foster + Partners

Article by Silvia Pelham

[1] Foster + Partners
[2] See Aleppo in Syria and Shibam in Yemen.
[3] The team worked with Jean-Marc Castera on arabesque decorative lattice features for exterior shading.
[4] See http://en.wikipedia.org/wiki/windcatcher.
[5] Masdar City is run on 100% renewable energy: 42% photovoltaic; 35% concentrated solar power; 15% ETC (evacuated thermal tube collector) and 8% on waste to energy.
[6]  UAE - United Arab Emirates.
[7]  10 Megawatt photovoltaic plant.
[8]  Concentrating solar power (CSP) using linear Fresnel reflector systems.
[9] Personal rapid transit (also called podcar) / freight.

Abu Dhabi Sustainability Week

Abu Dhabi Sustainability Week

The Abu Dhabi Sustainability Week (January 13-17) will be the most important event held in the Middle East on sustainable development, with participants from 150 countries.

In a couple of hours, the world’s deserts receive more energy from the sun than humankind consumes in a year [1], so it is a fitting setting for such a gathering, especially since the UAE prides itself on having the most sustainable city in the world – Masdar City.

With more than 30,000 anticipated participants, the week will have something for all – business opportunities, new technologies, financial challenges, investment solutions and fruitful partnerships.

Participants can choose to attend up to 5 distinct conferences and many other events during the week. Among them, the annual World Future Energy Summit (WFES), the International Water Summit (IWS), the International Renewable Energy Conference (ADIREC), the Young Future Energy Leaders programme, roundtable discussions, technology showcases, industry seminars, corporate meetings and many exhibitions focusing on energy and the environment.

Article by Silvia Pelham

[1] See KNIES, G & TRIEB, Franz – “Sun cheaper than oil” (2006)