Commerzbank Headquarters - Frankfurt,Germany

The Commerzbank is often sited as one of Europe’s first ecological high-rise towers and was quite radical in its approach to the environment and the comfort of the inhabitants. The brief went as follows: “The building should use ambient energy as much as possible to reduce the amount of fossil fuel derived power; users should be exposed to the beneficial effects of contacts with plants, and individuals are to have the possibility of opening their windows to be able to obtain fresh air, even on the highest floors”.

Fosters and Partners designed the tower with four-storey high gardens that spiral around a triangular floor plan. This allows each desk to view greenery and eliminate the monotony of large expanses of office space. The lifts, staircases and services are placed in the three corners to reinforce the sense of the village-like community of the offices and gardens. The 53-storey tower was built in close cooperation with the Bank, the Architect and the City Planners to integrate it into the neighbourhood. The building rises from the centre of the city block keeping the perimeter buildings intact and preserving the feel of the neighbourhood.

The natural ventilation allows for the offices on the exterior façade to receive air directly from the outside. The interior offices get oxygen from the atrium and internal gardens. This also reduced the need for large air handling ducts. The screens that surrounded the gardens can open at the top to control the internal climate and fresh air intake. There is a duct system to carry air down the corridor areas, which uses an intelligent system to automatically switch on when the air pollution is too high or if there is a storm. The building management system controls the heating and cooling systems by monitoring the heat generated by people and machines or controling blinds in the wall cavities. The system can be too sensitive however, and will turn off lighting in offices if no movement is detected. Rainwater is also harvested and used to flush the lavatories and some wash-basins only have cold water to save energy. The features of this building have resulted in saving two thirds of the energy costs. 

The Commerzbank does have some environmental drawbacks as the structural system and construction process contains high-embodied energy and due to large amount of core the use of space is inefficient.

GSW Headquarters - Berlin, Germany 

This scheme created the headquarters for GSW, which is Berlin’s city’s Housing Association, on an existing 60’s tower block. The design by Architects, Sauerbruch Hutton retained the original 17-storey block and added a new curved 22-storey block that was only 11.5 m wide. The design of this extra block enables a great deal of natural daylighting and natural ventilation. The building’s low energy design claims to reduce consumption by 40%. The double glass façade with blinds and a wind sail on top of the 81m high building are key visible features.

Bioclimatic considerations are important to the design. The outer skin acts as a buffer in winter, whilst absorbing heat in the summer. Inhabitants can control their own environment by opening windows or operating blinds to control the solar gain. The natural ventilation is supplemented by a mechanical system in winter.

 The tower also contributed to the regeneration of the area and is considered an entirely appropriate response to Berlin.

 (Source: (2001-02) Urban Sustainability Mini Project, MSc/Diploma In Energy Efficient Building, Oxford Brookes University School of Architecture & School of Engineering, UK)

RWE AG Hochhaus - Essen ,Germany

This is a circular building that is fully glazed and is recognised as bioclimatic for its intelligent façade that controls the internal climate. The double-skin façade was designed to offset winter heat loss and summer solar gain as well as assist natural ventilation and maximise natural daylighting. The façade consists of exterior safety glazing, fixed by bolts through fittings and a 50cm wide airspace, separating it from the interior glazing layer, which is composed of fixed and movable floor double-glazed panels. 

A further detail is the horizontal metal extrusion at each floor slab, which was formed as a ‘finishing mouth’ louver. This can be opened to let in fresh air at the bottom gap between the glazing layers or to exhaust air from the top of the airspace of the floor above. The insulating-glass interior lightly slides open up to 15cm wide, giving tenants control over how much air is admitted. This double skin system presents high value insulation and overcomes the inadequacies of openable high-rise windows by providing protection from noise and the ability to control dust-laden gusts. 

The resulting system lets in plenty of daylight to reduce the need for artificial light. Also, by exploiting the thermal lag of the ceiling’s exposed concrete slab, cooling loads are minimised. Assisted by perforated holes in the ceiling panels it absorbs excess heat during the day and radiates it at night. 

This building like the Commerzbank, has environmental drawbacks as the structural system and construction process contains high embodied energy and the space is also inefficient utilised due to the large amount of core space.  

(Source: (2001-02) Urban Sustainability Mini Project, MSc/Diploma In Energy Efficient Building, Oxford Brookes University School of Architecture & School of Engineering, UK)

Martini Towers -Brussels, Belgium

The Martini Tower is based in Brussels Centre International Rogier and was designed by Architects, Kohn Pedersen Fox at a price of £66m. The mixed-use project was a refurbishment of a prominent 30-storey tower in central Brussels that utilised environmental principals in construction and resulted in plenty of offices and residential accommodation. The building services strategy involved the innovative application of a double skin and thermal flue, and an integrated wind turbine to reduce energy consumption.

Holloway Circus -Birmingham,United Kingdom

Planning permission has been granted for the development of a major Eco-Tower in Birmingham’s Holloway Circus. The state of the art sustainable tower will be mainly residential with some retail and office use and will be considered the UK’s first Eco-Tower.  

The Holloway Circus Tower is an important step in tackling global environmental issues. It will work towards fulfilling the objectives set by the Montreal Protocol, the Kyoto Protocol and the Local Agenda 21 initiative called Silver Bullet. The tower has been designed to consume 40% less energy than a typical block. The environmental strategy for the 44-storey tower is to reduce the construction, installation and operational impacts of various elements of the building.  

Some of the environmental design initiatives for this landmark building, include:

·         Twin stair cores to stabilise the steel frame structure and allow for lightweight steel construction.

·         Manipulation of materials, structural forms and balconies to provide shade and environmental moderation.

·         Quality prefabrication of primary structural elements for speed of erection.

·         Building materials with low embodied environmental impact and the use of recycled materials.

·         Building orientation designed to minimise adverse impacts of the site, whilst maximising potential benefits.

·         Thermal massing used to capture passive solar gain in the winter season and nighttime ventilation to provide cooling in both the mid-season and summer periods.

·         Building fabric consisting of south facing and glazed double skin façade.

·         Adjustable internal louvres allowing control of solar gain and natural ventilation.

·         Mixed mode systems to take advantage of natural ventilation with additional mechanical cooling and heating control during summer and winter.

·         High-level sky gardens that are environmentally integrated with the landscape architecture.

·         Photovoltaic panels and wind turbines are proposed to provide renewable energy.

·         Borehole cooling and greywater recycling is being considered to reduce waste and manage water resources.

London Bridge Tower - London, United Kingdom

A 66-storey building designed by the Architect Renzo Piano will be built next to the major transportation node of London Bridge station. Local church spires and the sails and masts of the ships that use to populate the Thames in this area of Southwark inspired the designs for the tapered glass tower. Although it will replace the Commerzbank as the tallest tower in Europe, the aim of the design is to blend in with the location.  

The lower part will provide 27-storeys and 600,000 sq-ft of office space whilst the upper portion will offer a 15-storey hotel and individual apartments. The building will be a social space with public auditoriums, bars and restaurants in the centre and a public viewing gallery on the highest floor for visitors and local Londoners to view their surroundings.

Environmental features include a large open lattice, forming the apex of the tower, that would utilise high-level winds to help cool the building naturally. Current calculations show that the tower would use about half the energy of a conventional office building. Some of the main sustainable features are social and are intended to help regenerate Southwark, which is a central part of London that is just recently being redeveloped.  

While many tower blocks had a bad name, Renzo Piano said: "Towers are often symbols of arrogant power, but towers need not be that bad. This is a vertical city. Office towers have a bad reputation because they are selfish, they are totally enclosed worlds. But here we will have 10,000 people living and working in a 24-hour building."  

(Source: WORSLEY, Giles, 16^th March 2001 Daily Telegraph Website)

Elephant and Castle

The redevelopment of the Elephant and Castle could potentially provide four towers; one to be designed by Fosters & Partners and three by TR Hamzah & Yeang and HTA Architects. Ken Yeang will be bringing his experience of building bioclimatic towers, in collaboration with HTA Architects and Battle McCarthy, to develop three eco-towers at the Elephant & Castle. 

The Elephant and Castle area has suffered from poverty and bad planning. The redevelopment will aim to make the area more attractive to investors, the local community and people seeking residence in central London. The project needs to provide high-density living spaces whilst at the same time, offer a range of tenures and allow affordable choice. Ben Derbyshire of HTA Architects believes that one of the essences of sustainability is choice. If we give people proper choices the outcome will be sustainable because people will look after them. 

In Elephant and Castle, the aim is to make the most of using a combination of bioclimatic strategies to achieve sustainable towers. There are low temperatures in winter so the proposed approach is to use solar gain and other passive features that can also utilise the warm temperatures in the summer. Natural daylighting and ventilation will be integral to the design. Sustainable energy systems will be employed, such as photovoltaics, wind energy and CHP systems. There will also be innovative recycling systems for waste and water as well as methods of harvesting rain. The designers of the Elephant and Castle project are working with Thames Water to reduce water consumption as well as working with other utility companies and the community to create zero CO2 emissions energy supply.  

Battle McCarthy are working in partnership with Corus and British Telecom to develop a pre-engineered building technology for the project that will apply sustainable construction techniques, utilise green technologies and will be flexible to the needs of residents in accordance with ‘homes for life’ requirements. The building materials will have low embodied energy and come from sustainable material resources. All homes in the tower will be provided with information technology cabling and fitted with security sensors as well as systems for home health care services. These new building technologies will also provide employment and skill development opportunities for local people. 

There are many different pluses and minuses of living in a high-rise. Some of the benefits include the increased benefits of security; more shared facilities; reduced maintenance; and communal spaces, where there is an increased opportunity to interact and socialise. One of the primary objectives of the towers will be to try and produce a suburban house in the sky. 

These towers will be designed to include biodiversity through features such as the 'landscaped bridge' and vertical greening, which enhances the environment by encouraging species to move in from nearby green areas. At the base of the towers there will be a direct link to a large 6 ha landscaped park on the roof of a new shopping centre. The design will consider all details that have to be followed to create a sustainable tower, such as planting that follow the solar path and hardy species that can exist in high altitudes.  

Sky ZED 'Flower Tower' - Bill Dunster, UK

SkyZED stands for Sky Zero Emission Development and is designed by the Architect Bill Dunster. The design is currently being considered for the redevelopment of Bermondsey near Tower Bridge.

The design came about as a response to the negative environmental impact of conventional tower blocks, the need for high density and the limitations of the availability of affordable homes.

Many of the features used in this tower have already been successfully put into practice at another development created by Bill Dunster called BedZED, in south London.

The tower will achieve the following:

• Generation of all its own energy

• Maximising renewable energy such as wind, solar and biomass

• Recycling its own waste

• Over 200 sq metres of commercial and leisure spaces such as gyms, community spaces, restaurants and shops

• A mixed tenure community where everyone has the same high standard of home construction and access to the same resources

• Construction using reclaimed materials including slip formed ggbs concrete and reclaimed timber stressed skin panels

• Utilisation of a living machine which is an environmental sewage treatment system developed by John Todd

• Triple glazed windows for acoustic insulation as well as thermal protection in the summer and heat-loss insulation in the winter

• Pedestrian and cycle ramps that lead up to community facilities

The floor plate is arranged in what looks like four flower petals. Each flower petal will provide good views and natural daylight to a layout containing a combination of either two bedroom or three bedroom maisonettes. This design is expected to magnify wind speeds by four times to be exploited by vertical axis wind turbines. The wind turbines were chosen for their self-lubricating bearings, which make the system almost totally silent. Private balconies will open out to the edge of each panel where wind velocities are lowest.

The petals are joined every four floors by a skygarden that is covered in lawn. This floor has a communal lobby that provides access to all four lifts and is naturally daylit by a skylight that reveals the revolving blades of the wind turbine.

(Source: Bill Dunster Architects, ZEDfactory)

Tower Block Refurbishment - United Kingdom

Due to the large amount of tower blocks and social housing that exists in the UK, there has been some effort to refurbish the homes over the last 20 years. It was decided that they should be made more energy efficient rather than demolished to build new ones. The following are a few examples of some successful refurbishment projects.

York House – Bradford

The slab block tower was difficult to let out but was transformed into a warm and secure place after the local residents campaigned for refurbishment and stricter letting policies rather than demolishment. The tenants were consulted on the renovations, which included: external wall insulation in order to retain the central boiler plant; repairing and insulating the roof; replacing windows, balcony doors and front doors; repairs to spalling concrete; rubber floors on access routes for acoustic insulation; new fittings and rewiring of bathrooms and kitchens; a new lift and stairwell attached to the rear elevation, which is staffed by a concierge 24 hours a day; security cameras and external lighting. In 1991, this resulted in a reduction of more than £4 per week for heating and hot water for a two bedroom flat. Fuel consumption was reduced by around 35% and there will be 4.2 to 5.5 tonnes less CO² emissions per year for each two bedroom flat and from 3.5 to 4.3 tonnes for each one bedroom flat. This refurbishment has been a model for similar schemes on other tower blocks.

(Source: Case Study 67 of Best Practice Programme February 1993, Energy Efficiency Office, Department of the Environment)

Stannington Estate – Sheffield 

Three 15-storey blocks were refurbished under tenant consultations to reduce fuel consumption by approximately 50%. This was a result of: cladding the towers completely with brick with partial cavity filling; providing a new gas-fired district heating system to replace the under-floor electric system that previously existed; replacing the windows with double glazing; and new ventilation measures. Funding for the renovations came from the Housing Investment Programme and Estate Action. Other improvements included: enclosing and refurbishing the ground floor entrance; audio-visual entry phones for extra security; enhancing disabled access; refitting kitchens and bathrooms; and the external lighting and landscaping was improved. At each mid-floor flat there will be 3.5 to 9.5 tonnes less of CO² emissions released into the atmosphere per year and 3.8 to 13.3 tonnes less from the top floor flats.

(Source: Case Study 68 of Best Practice Programme January 1993, Energy Efficiency Office, Department of the Environment)

Middlesex House – Greenford, Brent

This project involved a housing association converting a disused office block was into 78 flats for homeless families. Energy improvements included: insulation to external walls and roof; reduction in glazing area; use of double-glazing; and replacement of heating system. The podium of the block was refurbished to provide a nursery, play area, adult recreation rooms, a laundry, management offices and offices to let. Security measures included a 24-hour concierge and a controlled door entry system. Other improvements were to rewire the entire tower and to provide two new lifts. The designer endeavoured to improve the appearance of the building in order to make it more of a landmark building. A central atrium was cut into the podium, which enhanced natural daylighting and gave the building an impressive entrance. The building was also enhanced by: decorative painting, steel work and projecting bay windows.

(Source: Case Study 173 of Best Practice Programme February 1996, Energy Efficiency Office, Department of the Environment) 

New Addington Estate – Croydon 

The refurbishment of this 11-storey tower block consisted of external insulation and aluminium overcladding, internal drylining to walls next to stairwells, double-glazing, roof insulation and a new heating system. The total cost of the renovations was £14,000 per flat but heat loss was reduced by 45% and weekly heating bills were approximately 80% less. 

(Source: Case Study 177 of Best Practice Programme February 1995, Energy Efficiency Office, Department of the Environment)

Vertical City Bionic Tower - Cervara & Pioz and Partners ,Spain

In 1992, the Architects María Rosa Cervera and Javier G. Pioz began their investigations into Bionic structures by studying Bio-Structures in nature and how this could be applied to modern structural engineering and architecture. Like Paolo Soleri, their explorations lead to the development of a whole new language of architecture. Scientific investigations with biologists, engineers, architects, and designers led to the discovery of a new architectural ‘bio-structure’ that would be able of reach a maximum height of 1.228 meters. They created a prototype for a bio-ecological habitat with a maximum capacity for 100,000 inhabitants and called it the ‘Vertical City - Bionic Tower’.  

The bionic philosophy came out of Russia in the middle 20^th century and basically accepts the superiority of nature-based technologies. Bionic Architecture applies engineering and architecture to the study of biological structures and processes of nature. 

The Vertical City Bionic Tower is one of the first models of this type of bio-ecological architecture. Based on principles of flexibility and the adaptation of biological structures, the building is able to adjust its height, capacity and operations to the different economic, environmental and social conditions of the cities it is built in.  

Under conventional models of town planning and densities, 100,000 inhabitants would occupy an area of land 4 kilometres in diameter with a significant immediate impact on the local environment. The Vertical City Bionic Tower, with the same capacity, will occupy an area of 1 kilometre in diameter with less impact on the local ecosystem.  

The Bionic Tower is composed of 12 vertical neighbourhoods, each with an average height of 80 metres. Each level has interior and exterior groups of buildings, situated around large vertical gardens and reservoirs. The ‘Island Base’ of the tower contains: hotels, offices, residential buildings, businesses, sports and cultural facilities, leisure centres as well as extensive gardens, lakes and communication systems.  

The investigations carried out by the designers created a new bionic theory based on the structural principles of ‘flexo-resistance’ species. The model is inspired by the scientific analysis of the transformations that the structures in vegetables produce when trying to grow taller.  

Under the name of ‘fractal bio-structure’ these Architects have developed radical structural and technological theories that are based on the idea of the ‘fractal microfragmentation of complex systems of dynamic efforts’. 

The main structural and communication systems between the different vertical neighbourhoods is organised in three crowns of 92 columns. These columns will transport inhabitants, water, waste and necessary energy throughout the complex.  

The tower's outside skin is inspired by the transpirant and resistant qualities of nest structures in nature. This allows the control of natural air and daylight to penetrate inside to create an internal microclimate. The external structure will also contribute to reducing the effects of the wind. 

The substructure is called a ‘floating foundation and antiseismic’ system and is inspired by the ‘flexo-plastic’ and isolated characteristics of root systems in large trees. This is designed to provide stability, by allowing the root system to transmit wind and seismic loads to the soil.  

The concentric rings of adult trees create a system of conduits for fluids that contribute to its structural stability as well as creating a defence against fires. Inspired by this, the Vertical City’s twelve vertical neighbourhoods are separated by watertight areas fifteen meters high that would provide a controlled area for evacuation in case of emergency.  

The designs of the tower would also allow lower levels of the vertical neighbourhoods to be completed and inhabited while construction could continue on the successive levels.  

(Source: http://wwwa011.infonegocio.com/699/index.html)

Helicoidal Skyscraper - Calabria, Italy