Hydroelectric generation
Hydroelectric schemes which exploit height difference in the flow path of water are the oldest method of generation from water. It involves damming a watercourse to create the necessary pressure to drive high speed impulse turbines. The Boulder Dam scheme in the USA was the first large-scale project implemented in the 1930s as a means of driving the country out of recession. One of the first major projects to be completed after the Second World War was the Aswan Dam scheme initiated by Colonel...
Types of solar thermal collector The flat plate collector
These units are, as the name indicates, flat plates tilted to receive maximum solar radiation. Behind the plate are pipes which carry the heat extraction medium. There are two types of heat absorbing medium, air and water. Water containing an anti-freeze solution is the most common and is circulated behind an absorber plate to extract and transfer its heat. In the UK they are usually limited to providing domestic hot water, mainly in the summer months. To exploit their efficiency to the full...
Internal air flow and ventilation
Air flow in the interior of buildings may be created by allowing natural ventilation or by the use of artificial mechanical ventilation or air conditioning. The production of buildings using more than one of these options is becoming more frequent. Such buildings are said to be 'mixed-mode'. The overriding principle should be to minimise the need for artificial climate systems and one way to achieve this is to make maximum use of natural ventilation in conjunction with climate sensitive design...
Beaufort court renewable energy centre zero emissions building Studio E
Where possible the reuse of existing buildings is the best way to meet the sustainability agenda. An excellent example of this strategy is the headquarters of an energy company near London. The description of the development by David Lloyd Jones of Studio E Architects is quoted at length as being the most appropriate explanation of the design strategy. Solar design aspects of the renewable energy centre and interim findings David Lloyd Jones, Studio E Architects The Renewable Energy Centre at...
Low energy Conference Centre Earth Centre Doncaster
This is a building built to the highest super-insulation standards which is no less than we would expect from its architect, Bill Dunster. It has natural wind-driven ventilation with heat recovery from exhaust air transferred to incoming air. Solar collectors on the roof direct warm water to a calorifier in an underground insulated 400 m3 tank. Heat is stored over the summer to be circulated throughout the winter, with a wood burning stove for backup heat. A wind generator mounted in the boiler...
Tools for environmental design
The three main categories of passive solar design, along with their subdivisions, are most usually applied within domestic-scale designs. However, similar principles have been analysed with reference to commercial developments. One assessment method that addresses this sector is the Lighting and Thermal Value of Glazing Method - the 'LT Method', developed in the UK. This method reduces a building to an orthogonal plan with core and perimeter zones. The perimeter zone is that which is subject to...
Evaporative cooling
Another case of 'nothing new under the sun' is evaporative cooling. One of the earliest cases of this being incorporated in a building is the Emperor Nero's megalomanic 'Golden House' which covered most of the centre of Rome. At its centre was the domed octagon room and in one of its sides a waterfall was inset, supplied by a mountain stream. No doubt it performed the dual role of architectural feature and cooling device. Evaporative cooling works on the principle that molecules in a vapour...
Small wind turbines
In this context 'small' means wind machines that are scaled from a few watts to 20 kW. Machines between 1 and 5 kW may be used to provide either direct current DC or alternating current AC . They are mainly confined to the domestic level and are often used to charge batteries. The larger machines are suitable for commercial industrial buildings and groups of houses. Small-scale electricity production on site has economic disadvantages in the UK given the present buy-in rates for small...
Direct gain
Direct gain is the design technique in which one attempts to concentrate the majority of the building's glazing on the sun-facing facade. Solar radiation is admitted directly into the space concerned. Two examples 30 years apart are the author's house in Sheffield, designed in 1967 Figure 5.2 and the Hockerton Project of 1998 by Robert and Brenda Vale Figure 5.3 . The main design characteristics are Apertures through which sunlight is admitted should be on the solar side of the building, within...
Construction technologies
Walls and rainscreens The glazed curtain wall has advanced considerably since it came into vogue in the 1960s. The repository for knowledge in this context is the Centre for Window and Cladding Technology www.cwct.co.uk . Metal panel systems are now available with integral insulation, for example EDM Spanwall which uses flat metal sheets pressure bonded to the insulation core. Precast concrete panels also come with integral insulation. Trent Concrete has introduced an insulated concrete...
Benefits
There is a significant improvement in comfort levels throughout the whole house. The walls of the building are protected from weathering, ensuring a longer life. There should be absolute protection from penetration by damp. The incidence of condensation is reduced to near zero. It allows the fabric of the home to act as a heat store - a warmth accumulator. It stabilises the structure, preventing cracking due to differential thermal expansion. Space heating bills can be reduced by up to 50 per...
Ecomaterials Concrete
As possibly the most extensively used building material, concrete attracts criticism from environmentalists on account of its carbon intensive production techniques and its use of a once-only natural resource, limestone. Cement is formed by heating clay and lime in a rotary kiln to a temperature of about 1450 C which produces some 3000 kg per tonne of carbon dioxide CO2 . In addition the heating process produces a chemical reaction through the conversion of calcium carbonate into calcium oxide...
Fuel cells
Looking towards the next decade, the source of heat and power for many homes could well be the fuel cell. This is an electrochemical device which feeds on hydrogen to produce electricity, heat and water see Chapter 13 'Energy options' . In January 2004 the first UK domestic-scale fuel cell began operation at West Beacon Farm in Leicestershire. The most common fuel cell at the moment is the proton exchange membrane type PEMFC which feeds on pure hydrogen. It has an operating temperature of 80 C...
Photovoltaic applications
Commercial buildings have perhaps the greatest potential for PV cells to be integrated into their glazing as well as being roof mounted. Even at the present state of the technology, Ove Arup and Partners estimate that one third of the electricity needed to run an office complex could come from PVs with only a 2 per cent addition to the building cost. The main advantage of commercial application is that offices use most of their energy during daylight hours. The case study of the Zicer building...
Prismatic glazing
Whilst the systems so far discussed rely on the reflection of light, prismatic glazing operates by refracting incoming light. The system consists of a panel of linear prisms triangular wedges which refract and spread the incoming light to produce a more diffuse distribution. The view out is substantially restricted, but the system can be used as an alternative to the reflective louvre system without some of its drawbacks. Glare can be somewhat reduced too. Maintenance is virtually eliminated if...
Cadmium telluride CdTe and copper indium diselenide CIS
These cells are a further development of thin film technology, having efficiencies of about 7 per cent and 9 per cent respectively. At present prices are comparatively high but will reduce as volume of sales increases. In summary, costs range between 2 and 4 per Wp. However, unit cost is not necessarily the only criterion. Different cells have varying optimum conditions which has been highlighted by a research programme recently completed by the Oxford University Environmental Change Institute....
The prospects for wood
The House of the Future raises the question of the structural use of timber in buildings. Timber scores well on the sustainability scale, provided it is obtained from an accredited source such as the Forestry Stewardship Council. The Weald and Downland Open Air Museum 7 miles north of Chichester is a national centre for the conservation and study of traditional timber-framed buildings. The Conservation Centre explores new techniques in greenwood timber construction. Edward Cullinan Architects...
Common architectural problems
Adverse effects of too much glass being underestimated. Maximisation of daylight can produce problems for VDU operators. Inappropriate window design lacking refinement and ease of control. Poor controls and user interfaces. Fitting-out which may contradict original design intentions, leading to poor performance. Tendency to highlight the positive and play down the negative. Downside risks not given the same weight as upside visions.
The photonic revolution
The battle between traditional electronics is being fought on two fronts information processing, in other words, computers. We are already into the era when information is transmitted by pulses of light rather than through a copper wire. Particles of light - photons - can carry many thousands of times more information than wires. Optical fibres work by trapping light within a solid rod of glass which is surrounded by a cladding material with different optical properties, that is, a lower...
Design considerations
In order to achieve successful daylighting design, the following aspects The amount of glazing has a clear influence on the amount of daylight available, but more window area is not always better, it may simply increase contrast. Large windows admit light but also provide heat gain and heat loss routes and thus potential thermal discomfort, especially from cold draughts near the windows. Allocation of rooms to facades should be appropriate to the activity -to do this successfully will require...
The Beddington Zero Energy Development BedZED
The Innovative Peabody Trust commissioned this development as an ultra-low energy mixed use scheme in the London Borough of Sutton. It consists of 82 homes, 1600 m2 of work space, a sports club, nursery, organic shop and health centre, all constructed on the site of a former sewage works - the ultimate brownfield site. Peabody was able to countenance the additional costs of the environmental provisions on the basis of the income from the offices as well as the homes. Though the Trust is...
Solar design Passive solar design
Since the sun drives every aspect of the climate it is logical to describe the techniques adopted in buildings to take advantage of this fact as 'solar design'. The most basic response is referred to as 'passive solar design'. In this case buildings are designed to take full advantage of solar gain without any intermediate operations. Access to solar radiation is determined by a number of conditions the sun's position relative to the principal facades of the building solar altitude and azimuth...
Active solar thermal systems
A distinction must be drawn between passive means of utilising the thermal heat of the sun, discussed earlier, and those of a more 'active' nature. Active systems take solar gain a step further than passive solar. They convert direct solar radiation into another form of energy. Solar collectors preheat water using a closed circuit calorifier. The emergence of Legionella has highlighted the need to store hot water at a temperature above 60oC which means that for most of the year in temperate...
The National Assembly for Wales Richard Rogers Partnership
Following devolution, the Principality of Wales was granted greater autonomy resulting in the need for an assembly building for which the Richard Rogers Partnership was appointed architects with environmental engineer BDSP. It is a classic example of architect and engineer working in concert from the earliest stage of the project. The design brief was for a building which reflected the democratic nature of government whilst also being a landmark example of low energy design. It also has to last...
Towards the less unsustainable city
The ultimate challenge will be to transform existing towns and cities so that they become less of an 'ecological black hole'. The city is an epicentre of consumption, but also capable of being the highest visible manifestation of civilisation - 'civis' the city. Cities have powerful symbolic resonance which means that there are considerable constraints on change. Over the next 50 years, barring catastrophes like sea level rise, the basic form and infrastructure of European cities will not...
Beddington Zero Energy Development BedZED
BedZED is not just another low energy housing scheme, it is a prescription for a social revolution a prototype of how we should live in the twenty-first century if we are to enjoy a sustainable future Figure 18.7 . The design was led by Bill Dunster Architects who are one of the UK's top evangelists for ecologically sustainable architecture with the services and energy strategy developed by Arup Associates. The Innovative Peabody Trust commissioned this development as an ultra-low energy mixed...
High and superinsulation
In recent years attention has been focused towards the use of very thick layers of insulation within the building fabric in order to minimise heat flow. This technique has become known as superinsulation. The use of superinsulation has so far been best demonstrated at the domestic scale. This may be partly due to the problems of overheating experienced in many larger, deeper plan commercial buildings, problems which override the benefits of reduced winter heating requirements. In the future,...
The parabolic solar thermal concentrator
This is another option for sun-drenched locations which focuses the radiation to produce intense heat - up to 800 C. A version in the United States links this to a unique helium-based Stirling engine. The concentrator mirrors produce about 30 kW of reflective power to the heat pipe receiver which is linked to the engine. The engine operates on the basis that the heat vaporises liquid sodium in its receiver at the focal point of the dish. Condensation of the sodium on the heater tubes raises the...
Unassisted natural ventilation
Pioneers of natural ventilation are Alan Short and Brian Ford in association with Max Fordham. Their first groundbreaking building in the UK was the Queen's Engineering Building at Leicester de Montfort University Short Ford and Partners . This building has been well documented and a particularly useful reference is Thomas, R. ed. 1996 Environmental Design, E amp FN Spon. Maintaining the principle of pure natural ventilation without mechanical assistance is the Coventry University Library, the...
Indirect gain
In this form of design a heat absorbing element is inserted between the incident solar radiation and the space to be heated thus the heat is transferred in an indirect way. This often consists of a wall placed behind glazing facing towards the sun, and this thermal storage wall controls the flow of heat into the building. The main elements contributing to the functioning of the design are High thermal mass element positioned between sun and internal spaces, the heat absorbed slowly conducts...
facilitates heat recovery
An example of a climate facade building is the office development at 88 Wood Street in the City of London by the Richard Rogers Partnership RRP . The requirement was for floor to ceiling glazing which can create a problem of solar gain which is exacerbated by the heat from computers and, in this case, a high services loading. The facade developed by RRP and Ove Arup and Partners consists of a double glazed external skin made up of some of the world's largest double glazed units measuring 3 m X...
The ecological tower
Surely an oxymoron The orthodox 'green' would rule out anything above about 12 storeys since this is the height at which natural ventilation in the western European climate zone is said to become impracticable. Tower blocks usually require a heavy engineering services system. Also the construction energy costs rise significantly every five floors or so. However, the ecological tower block has its advocates, most notably Ken Yeang from Kuala Lumpur. He pioneered the idea of gardens in the sky...
Photochromic thermochromic and electrochromic glass
Each of these terms describes a variety of glazing in which the transmission properties are variable. Extensive opportunities exist for the development of some of these technologies to allow dynamic control of light and heat gain to match building and occupant requirements. Photochromic devices change transmission in response to prevailing radiation levels. Small examples have been in everyday use for some years in the form of sunglasses and spectacles. These react automatically to light...
Types of smallscale wind turbine
Most small systems have a direct drive permanent magnet generator which limits mechanical transmission losses. Systems under 2 kW usually have a 24-48 volt capacity aimed at battery charging or a DC circuit rather than having grid compatibility. Up to the present, horizontal axis machines are much more in evidence that the vertical axis type even at this scale. These machines have efficient braking systems for when wind speed is excessive. Some even tip backwards in high winds adopting the...
Mechanically assisted ventilation
Rotating cowls was the system adopted by Michael Hopkins and Partners with Ove Arup and Partners in the Nottingham University Jubilee Campus Figure 12.9 . This ventilation system is the successor to Hopkins' and Arup's innovations at the Inland Revenue HQ also in Nottingham, and Portcullis House, Westminster. These led to a low pressure mechanical system linked to heat recovery via a thermal wheel which recovers 84 per cent of the exhaust heat. The mechanical system requires 51 000 kWh per year...
Ecological City of Tomorrow Malmo Sweden
A European Commission demonstration project is almost completed in Malmo, comprising a whole new district consisting of housing, shops, offices and other services. It aims to be a zero net energy scheme, with its 11 GWh year energy demand making no net contribution to carbon dioxide CO2 emissions. It is being built on a reclaimed industrial site by the Ribersborg beach and close to the historic centre of Malmo. The project is the first phase of a 10 year programme to make the city of Malmo a...
Heat reflecting and heat absorbing glazing
These products are usually considered for application in situations where overheating poses a risk. Visible light and solar heat gain are both parts of the electromagnetic spectrum of energy emitted by the sun. The interaction of glazing with light and solar heat has three components reflection, absorption and transmission. Modifications in the proportions of reflected, absorbed and transmitted radiation could be engineered by changing the glazing system properties. There are several ways of...
Transparent insulation materials
Transparent insulation materials usually abbreviated to TIMs are a class of product which make use of particular materials to enhance the solar heat gain whilst simultaneously reducing the heat loss by conduction and radiation. The technology has similarities to the passive solar thermal mass wall designs already described, except the gap between glazed outer skin and the surface of the wall which faces into it contains insulation which is transparent rather than just air. The insulation allows...
Tidal energy
Tidal energy is predictable to the minute for at least the rest of the century. Tide levels can be affected by storm surges as experienced dramatically in the UK in 1953. The British Isles benefit from some of the greatest tidal ranges in Europe. In summary, there are at least four technologies that can exploit the action of the tides, offering reliable electricity in the multi-gigawatt range. They are Trapping water at high tide and releasing it when there is an adequate head is an ancient...
Building integrated systems
The Vivo building illustrates one version of a building integrated wind generating system. There is increasing interest in the way that the design of buildings can incorporate renewable technologies including wind turbines. Up to now such machines have been regarded as adjunct to buildings but a concept patented by Altechnica of Milton Keynes demonstrates how multiple turbines can become a feature of the design. The system is designed to be mounted on the ridge of a roof or at the apex of a...
Three technologies the marine environment
Two quotes set the scene for this chapter A sustainable energy system is probably the single most important milestone in our efforts to create a sustainable future . . . Decarbonisation of the energy system is task number one. Oystein Dahle, Chairman. Worldwatch Institute Global civilisation can only escape the life-threatening fossil-fuel resource trap if every effort is made to bring about an immediate transition to renewable and environmentally sustainable resources and thereby end the...
The external environment
The orientation of a property can have a significant impact on the extent to which it is adversely affected by wind. This can create a pressure difference between the faces of a building positive on the windward side and negative on the lee face. This means that cold air tends to be forced into the windward elevation and warmth sucked out of the lee side Figure 8.12 . The UK has one of the most turbulent climates in Europe. In the UK the average wind speed for 10 per cent of the time ranges...
The David Wilson Millennium EcoHouse
A demonstration Eco-House has been built in the grounds of the School of the Built Environment, University of Nottingham Figure 8.3 . It is designed as a research facility and a flexible platform for the range of systems appropriate to housing. Its features are PV tiles integrated into conventional slates providing 1250 kWh year solar collectors of the vacuum tube type on the south elevation to meet the demand for domestic hot water light pipe illuminating an internal bathroom and providing...