FURTHER TECHNICAL INFORMATION A sustainable solution
Contents
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One of the most energy intensive countries in the world Current technologies: Land Requirements Current Technologies: A Sustainable Solution Early Research Population Increase Ideal Community Size Population Density Available Jobs At the scale of the UK with a population of 100 million
Current Land Usage Urban Footprint Food Production Aquaponics
Food Production Area FoodTubes
Household Energy Requirements Water Source Heat Pump
Island Energy Requirements And Storage Photovoltaics Tidal Power Algae Energy Storage Algae Energy Storage: Biodiesel Algae Energy Storage: Hydrogen Waste Water
Carbon Footprint of Materials: CLT and Total Carbon Footprint of Materials: CLT Figures Carbon Footprint of Materials: Steel Figures Carbon Footprint of Materials: Concrete Figures Double Skin Facade Double Skin Facade: Pros and Cons Passive Heat Recovery Ventilation
Bridge Supports References
One of the most energy intensive countries in the world
As the world will inevitably have to wean itself off fossil fuels, almost all of our alternative energy resources will be costly in their land consumption. The UK, along with Japan and South Korea present the most demanding energy to land ratios in the world.1 around 1.2W/m2 which when considering the average energy output of the sun being 100W/m2 this doesn’t seem like such an issue, but...
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Current technologies: Land requirements
These demonstrate the scale of a certain energy production required to power the UK and the cost of each per Watt 7
Each of these sustainable fuel sources are being implemented in the UK’s sustainable strategy apart from algae farming, which has instead had million invested in the technology as it is cheap, land efficient and can used as an alternative to diesel, the US air-force mixes its jet fuel with 50% biofuels such as Algae. We notice through this diagram that wind and solar power stations both offer cheap large scale energy production, wind being the cheaper yet more space demanding alternative to solar power. But none the less, to power the UK, half of its land would need to be Wind turbines, or a quarter solar panels
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Current technologies: A sustainable solution
This diagram displays a similar sustainable energy strategy to the one implemented at the moment, although expanded to provide fully for the UK This has led to a dramatic increase in nuclear power (debatable sustainable) as well as importing solar and biomass energy from more land rich and/or sun intensive countries
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Early research
My initial study focused on the ratio between land and energy (W/m2), with the idea of promoting the worlds ability to provide sustainably for its inhabitance, as a liftime of pessimism about this has led to our generation to believe that it isn’t possible for our world to sustainably provide for itself. I was going to achieve this by dividing the island up clearly into areas designated to energy and food production as well as housing to show the requirements of our land in order for us to live sustainably.
But by separating us from our sources of consumption, such as power plants and farms, our lack of awareness will lead to us continuing to unknowingly mistreat our earth. Therefore the integration of energy and food production within a homogeneous city system is vital in order to distil an understanding of the consequences of all that we consume.
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Population increase
I must also consider the strains on the UK and London that will be inflicted due to our rising population For this I consulted many population projections for the UK in order to reference an accurate prediction for the population plateau Predictions ranged from 80 to 100 million For this project I will consider the highest estimation so as to design a system around one of the most demanding energy/land requirements that the world may ever have to face
Current Population: 64M Population Projection 2115: 100M2
This is 150% of our current population and would increase the UK’s population density (pop./Km) from 252 to 412 Meaning Trinity Buoy Wharf, with an area of 0.0613 km2 would have to house and fully provide for at least 25 people
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Ideal Community Size
Reading into Dunbar’s studies of ideal human population sizing, he concludes that figures ideally lie between 150 and 250 for social coherence. But with regulated systems in place one can maintain larger populations.3 Predictions made by Bernard and Killworth showed a mean result of 290 social ties 13 Because the site is situated in within Londons highly dense fabric, and as both Bernard and Killworth as well as Dunbar state that higher number communities are more optimal for efficient living systems, I will consider a scale on the higher end of both their predictions.
Trinity Buoy Wharf will house: 260 Inhabitance 60 Affordable short term leases (scientists/artists)
This is over around 13x greater than the required population of the island
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Population Density
Making the Population density 5000 pop./Km2 With a population density at the low end of the four neighbouring boroughs
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Available Jobs
The Island will provide almost an equal number of Job opportunities as its residents, including existing industries such as artists studios, the gym and the Thames Clipper headquarters as well as an extension of the existing Primary school to triple its current capacity Like a village, the island is not designed to work completely independently. If other similar communities were to arise around Trinity Buoy each would have its own specialities, such as offices, education, factories ect.
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At the scale of the UK with a population of 100 million
1 : 5,000
If this system was to be implemented at the scale of the UK it would be connected by main transport routes consisting of a road, FoodTubes and rail. Otherwise between communities the land is forest, wild farmland, pastoral farming and sports facilities
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1 : 50,000
The diagram to the right shows the spacing each community would be apart from one another in order house the UK in half of its land. (created through grasshopper)
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1 : 5,000,000
Here the community pattern on the page before is covering half of the UK, creating adequate amounts of housing energy and food. The pattern surrounds existing major and leaves areas for wilderness exploration outside of the United Kingdoms new boarder
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Current land usage
Currently the UK is consumed by mostly Enclosed Farmland, with very little offered to the Earth as mountains, moorlands, heaths and semi-natural grassland. At the moment 6.9% of the UK’s land area is classified as urban This is including rural developments and roads and excluding cities green spaces and domestic gardens
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Urban Footprint
If my proposal was to be implemented to the scale of the UK it would half our urban footprint and dramatically reduce our farmland requirements. And even in the year 2115, with the UK’s population at 100 million and without any high density accommodation, this system will achieve an urban footprint of just 4.8%
BedZed, which houses the same number of people under a similar ethos would leave a footprint of 9.1% almost double my proposal
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Food Production
Enclosed farmland covers 70% of the UK5 due to arable and organic farming being highly land demanding, as well as energy and resource intensive.
It is for these reasons I have chosen to peruse the hydroponics (aquaponics/airoponics) technologies: • Closed systems can deliver near zero waste water all year round • Smaller footprints, therefore less impact on the natural environment • Marginal land is not an issue • Grow foreign plants in local climates • Controlled environment allows better use of IPM and beneficial insects with much reduced sprays • Higher Brix (sugar) levels deliver sweeter flavoursome fruit and longer shelf life • Year-round supply of consistent quality and quantity to meet consumers needs • Environmentally sound and responsible growing system • No weeds, no weeding, no herbicides! • Higher production per hectare (1ha glasshouse produces the same as 9.4ha field, or in my case more) • Higher returns for farmers’ efforts
Trinity Buoy Wharf will supply its inhabitance with all their required vegetables through a large aquaponics and hydro/airoponics centre, other root and exotic vegetables will be grown between the walls of a derelict warehouse, and fruiting trees will be scattered within the forest
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Aquaponics
Aquaponics combine conventional aquaculture (raising aquatic animals such as snails, fish, crayfish or prawns in tanks) with hydroponics in a symbiotic environment. Water from the aquaculture system is fed to the plants where the by-products are broken down by nitrification bacteria into nitrates and nitrites which are utilized by the plants as nutrients. Water is then recirculated back to the aquaculture system An American company Bright Agrotech are industry leaders in this technology, their An research is extensively recorded online. They have recently funded the largest London aquaponics greenhouse, GrowUp, which has provided all the knowledge I require to implement this technology just a few miles from this up and coming scheme.
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Bright Agrotech have extensively documented the technology behind their highly space efficient ‘ZipGrow’ towers that I will be using in the greenhouse for both the aquaponics and hydroponics systems This vertical growing system gravity feeds the plants by dripping the nitrate rich solution through foam within a plastic sleeve, this foam disperses the droplets to fully cover the root, a method equally as efficient but much more water efficient as the clay pellets used in flatbed growers
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New towers are added in waves as soon as the tower behind has leaves large enough to capture sunlight either side of the newly placed towers. This can be repeated four or five times, producing enormous yield in very little space
The ZipGrow towers are removable and easily transported, allowing customers to pick their own vegetables fresh from the plant.
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Food Production Area
There are very few statistics on aquaponics yield, here are the tow most comprehen- sive: Portable Farms, an aquaponics company that provides for customers wanting to set up their own conventional flatbed system, claim that one can yield all their table vegeta- bles and 25% of their protein with just 25sqft = 2.31m2 Kate Humble the television presenter also using the less efficient flat bed system at a size of 80m2 in South Wales produces 30 to 35 kg of fruit and vegetables a week and 200 kg of fish a year I find the Portable Farms statistic hard to believe especially for a flatbed system, I have therefore take it with a pinch of salt:
I will consider this as 3m2 per person 3m2 x 320 inhabitance = 960m2 of growbed space This will brake up into: 730m2 of aquaponics (hydro/aeroponics) systems Producing: all table vegetables and carp/tilapia ect. 806m2 of conventional walled garden space Producing: root vegetables and others above can’t produce
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FoodTubesTM 6
This technology will shuttle food, waste, laundry and deliveries from the islands heart to any of its inhabitants in a capsule 60cm in diameter, powered fully by linear induction motors I am incorporating this technology not only to improve the quality of life for the inhabitants but also to promote an automated transport system that could potentially eliminate all goods transport emissions This technology has been extensively researched by a consortium of Oxford based academics, project planners, and engineers, in order to promote alternative highly efficient methods of transporting goods in order to reduce CO2 emissions Future towns will be linked by FoodTubes, as currently 92% of the fuel used to transport food and ‘supermarket consumer goods’ moves the vehicles - only 8% moves the cargo This will also assist in making the island zero waste, as their will be no need for packaging, waste will only come from non compost-able foods and discarded broken belongings
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Household Energy Requirements
Per average UK household: 8 Electricity consumption: 4000kWh 457W Gas consumption: 14000kWh 1600W
Gas energy consumption proves a big issue, that must be tackled by using electrical heating, as oppose to conventional boilers
gas
electricity
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FoodTubes: Technical
Here we see a section running through the centre of a dwelling revealing the capsule system.
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Water Source Heat Pump
This will be achieved by using a water source heat pump, as besides the Thames heat can be absorbed much faster through the water than the ground. this is because of the reasonably consistant 8-10 degrees two meters beneath its surface where the piping will lie. The flow rate of the Thames passing over the piping will transfer heat to the refrigerant faster, and therefore less piping and a smaller pump will be required
This technology has already been applied at the royal festival hall as well as the new develop This technology has already been applied at the royal festival hall as well as the new develop- ment Kingston Heights, both further up the Thames
The water source heat pump used in Kingston Heights proved about 4.5 times more efficient than a conventional system, enough to make it financially viable to go electric over gas 9
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1. This junction needs to protect and insulate the exterior and in- terior of the building, This is also the point that other service piping enter the exterior facade. Flaps will prevent the movement of air between the two sec- tions, and insulation will stop conduction.
2. The capsules will run on rails holding it above the linear in- duction motor by which it is powered, within the capsule is the storage area that rotates about one axis to prevent damage during acceleration and the ascent/descent when within the dwelling
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The system on the island
WSHP electricity: 1600/4.5 = 356W
Therefore average household electrical consumption: 457W + 356W = 813W
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Island Energy Requirements and Storage
The Island holds 90 households, and the equivalent of 40 in other buildings = 130 Therefore the islands energy requirements are: 130 households x (356w + 457W)
= 105,690W roughly 100kW
A steady flow of energy throughout the day will be achieved by the integration of electric cars (with ca- pacitor of quinone battery storage) within the islands heart, storing energy during the day and releasing it when required at night. One Nissan leaf is able to power an average home for two days 10
Aziz and the quinone discovery
We must therefore include the energy consumption of the electric cars. Lets make this equivalent to 3 fully loaded, average electric cars traveling at 60mph non stop throughout the year (one electric car would consume 10kW) Therefore I will include 30kW towards car transpor- tation
Also I must include the FoodTube system, which I will consider as using 10kW
Therefore overall consumption is 140kW
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Photovoltaics
Conventional single-crystal silicon solar cells are facing increasingly strong competition from thin-film solar cells based primarily on polycrystalline absorber materials, such as cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS). However, if photovoltaics are to make a significant contribution to satisfy global energy requirements, issues of sustainability and cost will need to be addressed with increased urgency. There is a clear need to expand the range of materials and processes that is available for thin-film solar cell manufacture, placing particular emphasis on low-energy processing and sustainable non-toxic raw materials. The potential of new materials is exemplified by copper zinc tin sulphide, which is emerging as a viable alternative to the more toxic CdTe and the more expensive CIGS absorber materials.12 It is now possible for photovoltaics to absorb 50% of the suns energy But current rooftop PV’s reach just 15% Predictions say we will reach an efficiency of 30% in the next ten years 11 Therefore I will be using 30% efficiency photovoltaics
UK’s average sun intensity is: 100W/m2 11 Therefore energy produced: 30W/m2 All 7x7 rooftops in the development = 2,156m2 All 7x7 rooftops in the development The heart canopy covers = 1,369m2 Total rooftop PV area = 3,452m2 Therefore PV energy production = 3,452m2 x 30W/m2 =103,560W
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Tidal Power
Hundreds of floating tidal power turbines are to be installed besides HQS Wellington producing 50MW! 12
Just two 2 meter diameter machines will be capable of producing 50kW, balancing the islands energy re- quirements These will be installed between the island and the large vessel dolphins, as here in the fast flow of the rivers bow they will be most efficient
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Algae Energy Storage
Despite appearing adequate, we require energy storage in the form of algae biofuels and hydrogen production.
Algae will store excess summer energy to be used during the winter nights
But as energy is absorbed through photosynthesis, the theoretical maxi- mum efficiency of this technology is 11% compared to PV’s 30% This will take up 1/3 of the Heart’s sun space, fuelling the island during winter nights as well as being used for research and development the ‘Making Labs’
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Algae Energy Storage: Biodiesel
This is the type of system that will be used, large glass tubes similar to solar panels have algae pass through that is abler double in weight in just hours under the sun, this is piped off, pressed, and dried into cake, that can be used as a solid fuel, a protein supplement or animal feed. Oil then settles on the water which is tapped as biodiesel and burnt in a conventional system, the CO2 released can be fed back into the systems start point along with the required nutrients and the re- cycled water and the process begins again.
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Algae Energy Storage: Hydrogen
The use of hydrogen as an energy store is becoming more popular with a few London Bus routes using Hydrogen fuel cells to power them across London. The bus may just leave a trickle of water as its exhaust, but in fact, currently the Hydrogen production pro- ceed through electrolysis consumes more electricity than the energy it stores, making the ordeal less efficient than a battery Although algae, under certain circumstances can produce Hydrogen directly through an alternative to photosynthesis:
Photobiological production This is a process where algae breaks down water into Hydrogen and Oxygen due to being starved of sulphur in their nutrient mix, requiring no form of electrolysis, only consuming energy in the form of sunlight and and its nutrients, and later sup- plying Hydrogen fuel cells
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Carbon Footprint of Materials: CLT and Total
Carbon footprint of materials in a single housing units: 6 tonnes of CO2 in steel components 44 tonnes of CO2 in concrete foundations -264 tonnes of CO2 in cross laminated timber structural components = -210 tonnes of CO2 consumed by each building
Cross laminated timber will make up the buildings superstructure, they are are produced from kiln-dried finger jointed spruce/fur planks which are sorted and cut into sheets. These sheets are then stacked to a thick- ness of 200mm and layered at right angles, glued under a high pressure bonding system perpendicular to one another A number of affordable high rise CLT apartment block have recently been erected in East London
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Carbon Footprint of Materials: CLT Figures
Cross Laminated Timber Structure KLH UK state that 1m3 (480-500kg ) removes 0.8 tonnes of CO2 One 3000x2500x150 panel weighs 3 tonnes 6 of these panels make up a single floor plate 6 of these panels make up the walls between each floor plate With 5 floor plates and 4 sets of walls 9 x 6 = 54 54 x 3 = 162 tonnes of CLT in each building 162 x ( 0.8 tonnes of CO2 / 0.49 tonnes (480-500kg) ) = 264 tonnes of CO2 Therefore 264 tonnes of CO2 will be locked within each building
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Carbon Footprint of Materials: Steel Figures
Steel 1 ton of steel = 1.75 tonnes of CO2 2 pathway supporting columns: roughly 25kg a foot, with the average house being 50 ft 1000kg x 2 = 2 tonnes steel pathway and piping for each building roughly 4 tonnes Therefore 6 tonnes of steel = 10.5 tonnes of CO2 emitted by each building.
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Carbon Footprint of Materials: Concrete Figures
Concrete foundations Portland cement produces 870kg of CO2 per ton By acknowledging Admiral Building Movers that estimate a building of this size would have foundations weighing 50 tonnes. As 1m3 of concrete = 2.5 tonnes This suggests that the foundations consist of 20m3 of concrete, which seems about right. Therefore each buildings foundations will emit 50 x 870 = 43,500kg = 44 tonnes of CO2
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Waste Water
Current waste water treatment goes through many different energy intensive stages and can travel 50 miles until it is finally sold as a compost and used to feed our food.
Despite the importance of removing subterranean services from the community, I do not wish to pump waste water from the lower levels back to the pedestrian footpath, due to this being a very active, material and energy intensive solution.
I have therefore considered the use of a septic tank with reedbed sewage treatment situat I have therefore considered the use of a septic tank with reedbed sewage treatment situat- ed in the forest between certain dwellings, an option which provides better quality effluent than that of a soak away. This passive approach is highly energy efficient, low cost and low maintenance.
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In this process water enters a standard septic tank (requiring empting every several years), the liquid between the sediment/sludge layer and the scum that forms on top is piped out and trickled through the reedbed where it is cleaned by micro-organisms living on the root system.
Two homes would require just 12m2 of reedbeds 14
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Although due to reported incidents relating to infections caught whilst maintaining reed- beds, as well as other health issues due to close proximity to the effluent, this system will not be used on the island unless a completely safe forest environment can be created. Instead the island will expand on the existing Victorian sewage system used on the island, running beneath the road, this will be the only underground services on the island.
Floating algae pods 15
As the community will be promoting algae based technologies, producing it at its heart for experimentation in the labs, it is possible that an algae based waste water system can be implemented, as many of algae’s required nutrients can be found in our waste water.
Currently Jonathan Currently Jonathan Trent an environmental scientist is pushing the concept of farming algae within our rivers and seas in soft plastic permeable containers. This system will be attached to our waste water outlets where the algae would take up nutrients and part filter the water before it is released into the river. This system has been tested in San Francisco where it was successful but the cost and maintenance at this stage is too great.
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Double Skin Facade
A double skin facade allows for a passive approach to the dwellings comfort levels, providing good insulation during winter, and ventilation levels driven by the stack effect created between the two glass layers delivering high air-changes/hour to keep each dwelling cool during the summer.
Summer Months during CDH, vents are opened and the stack effect draws air through the building through pressure differences.
Winter months during HDH (the rest or the year) vents are shut and the space between the two facades becomes a large insulating cavity.
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Double Skin Facade: Pros and Cons
Negative: embodied energy of DF higher than SF capital costs are higher than SF design costs are higher than SF engineering expertise required contractor expertise and experience required
Positive: No mechanical cooling systems required con- suming energy and space Better control and access to daylight Higher degree of interior comfort for occupants Higher level of user control of façade system Greater sound insulation Good facade U-Values for winter
The facade will be controlled by two mechani The facade will be controlled by two mechani- cal openings at the top and bottom of the facade inspired by the successful GSW building in Berlin.17 Each floor will have a full length slid- ing door allowing access to the cavity for venti- lation and maintenance. This system was an- other influence to the buildings form, as by rais ing the building the facade inlet is far more simple and efficient.
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Passive Heat Recovery Ventilation
Ventive is a new product designed to work in existing dwelling infrastructure such as chim- ney stacks. Its form controls air pressures such that wind passing by this omni directional cowl creates a pressure difference between the inlet and outlet. Beneath this, within the flue of the system is a simple but effective heat exchanger that makes this system unique. Overall this method of continuous ventilation avoids heat loss, running costs and onerous maintenance requirements. 16
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Heat Exchanger
In order to ventilate the building during the winter months (when the stack effect created by the double skin facade causes too much heat loss), I will use a simple passive heat recovery ventilation system, adapted from a product by Ventive.
omni directional cowl
The ductwork for this system will be located at the corners opposite the structural supports for the suspended pedestrian bridge. Here the system can ventilate all rooms in the building that don’t require mechanical extraction that the opposite wall provides, inhabiting a space that requires no primary structural support.
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Bridge Supports
It is important that the footpath is lightweight above the forest, here is how I pro- pose this be acheived.
Either side of the double skin facade is void, maintaining the continuity of the structural walls. At the rear of each dwell- ing, flanking the circular window is a space housing the passive heat recovery ventilation ducting, and at the front it houses a steel column that supports the pedestrian footpath between them and the neighbouring building
This takes load from CLT structure and simplifies the engineered solution. The steel column attached to the vertical CLT panel has two steel rods joined to its end, one anchored to the buildings foundations, cross bracing the building from the lateral loads that the bridge will exert on the structure, the other is connected to the lightweight steel frame footpath with foodtube beneath.
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References
1 - Reality check on renewable - TEDxWarwick - David MacKay 2 - Principal and variants - UK National Population Projections - Office for National Statistics 3 - Dunbar, R.I.M. (1993), Coevolution of neocortical size, group size and language in humans, Behavioural and Brain Sciences 16 (4): 681–735 4 - Box 1.2 - 4 - Box 1.2 - The UK’s Broad habitats - 2012 UK National Ecosystem Assessment report 5 - Table 2.1 - Agriculture in the United Kingdom 2012 - Department for Environment, Food and Rural Affairs 6 - FoodTubesTM - Noel Hodson blogspot 7 - The result of hundreds of sources 8 - Energy consumption in the UK 2014 - Department of energy and climate change 9 - Kinsgston Heights - Mitsubishi Electrics Case study 10 - Power Control System - Wind, Waves and Whiskey - fully charged show 11 - Figure 6.2 - 6 Solar - Sustainable energy, Without the hot air 12 - 12 - Towards sustainable photovoltaics: the search for new materials (2011), Article Peter, L. M. 13 - Alternative Numbers - Dunbar’s Number - Wikipedia 14 - What are reed beds? - CAT information service 15 - Energy from floating algae pods - TED Global 2012 16 - Ventive the future of ventilation - Ventive short presentation - SuperHomes 17 - GSW Tower Block Berlin - Detail Magazine article 3/2000 17 - GSW
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