Wind Energy DIY Guide
Up to the present, horizontal-axis machines are much more in evidence than 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 so-called 'helicopter position'. There are advantages to horizontal-axis machines such as Returning to the horizontal-axis machines, a development from the 1970s has placed the turbine blades inside an aerofoil cowling. A prototype developed at the University of Rijeka, Croatia, claims that this combination can produce electricity 60 more of the time compared with conventional machines. This is because the aerofoil concentrator enables the machines to produce electricity at slower wind speeds than is possible with conventional turbines. The cross-section of the cowling has a profile similar to the wing of an aircraft, which creates an area of low pressure inside the cowling. This has the effect of accelerating the air over the turbine...
Energy consultants BTM produced a report in 20051 International World Energy Development -Word Market Update 2004. It showed that, on the world scale, 2004 saw 8154 MW of new installed capacity bringing the global total capacity to nearly 48 GW This represents an increase of 20 . Over the years 2000-2005 growth has averaged 15.8 per year. Europe accounted for 74 of the total in 2004. In that year Spain was the leading market with 2064 MW replacing Germany as the leader with its 2054 MW Growth stalled in the Americas in 2004 with only 516 MW as against 1818 MW in 2003. The report predicts that, as a result of the Kyoto ratification, there will be increasing world interest in wind power. Assuming that the manufacturing base keeps pace with demand, annual installation could reach 29 GW by 2014 with a total accumulated capacity of 235 GW China increased its capacity from 98 MW to 198 MW over the same period. It plans to builds its first offshore project in the Bohai Sea off the northern...
Recording periods of between 10 minutes and 2 hours provide reasonably stable measurements of the mean component of the wind. In the UK a recording period of 1 hour at a height of 10 m is adopted. As previously highlighted, the mean wind speed varies with height from the ground due to drag at the earth's surface. A number of laws have been derived to describe this variation, the most popular of which is the logarithmic law adopted by Eurocode 1 Parts 1-4 (British Standards Institution, 2005). This gives the mean wind speed Vm(z) at height z above the ground as a function of the basic wind speed Vb as
There are many ways to use a gust of wind to make a light bulb glow. In fact, a 1980 issue of Wind Power Digest analyzed nearly 50 different wind generators in thatyear alone. Little wonder, because wind power is a never-ending nonpolluting source of energy all over the world. On the minus side, the finest-made wind propeller can be at most only 59 percent efficient because when the wind strikes the propeller blades, at least 41 percent of the energy is deflected outward as the blades are pushed around. These system's efficiencies are further lowered by similar imperfections in every other mechanical and electrical subcomponent. However, low machine efficiencies never stopped Henry Ford, whose automobile engines even today Since a horizontal-axis-bladed wind generator mounted on a mast or tower is generally the most efficient and reliable method today, only it will be discussed further. One's components are described below. Six mph is the minimum average windspeed for feasible...
Ce exposure factor that reflects the changes in wind speed with height and variations in the surrounding terrain dimensionless Reference Pressure q. The reference velocity pressure q, in kilo pascals, is determined from referenced wind speed V by the equation The factor C depends on the atmospheric pressure and air temperature. If the wind speed V is in meters per second, the design pressure, in kilo pascals, is obtained by using a value of C 650 x 10-6. The reference wind pressure q, is given for three different levels of probability being exceeded per year (1 10, 1 30, and 1 100), that is, for return periods for 10, 30, and 100 years, respectively. A 10-year recurrence pressure is used for the design of cladding an for the serviceability check of structural members for deflection and vibration. A 30-year wind pressure is used for the strength design of structural members of all buildings except those classified as post-disaster buildings. A 100-year wind is used for the design of...
The dynamic response of aerodynamically stable structures may be predicted using either frequency or time domain methods. The latter method requires the generation of spatially correlated wind histories consistent with the design wind power spectrum. A large number of sets of artificial time histories must be processed in order to ensure that the analysis is statistically representative. The frequency domain method is based on the wind power spectra directly and thus produces a computationally efficient upper bound assessment of structural response. The aim of the method originally proposed by Davenport (1961) is to predict the statistical properties of the structural response starting from knowledge of the statistical properties of the forces due to wind. The frequency domain method is limited to the analysis of structures whose dynamic response is linear. Consider an equivalent single-DOF system subject to along-wind buffeting shown in Figure 16. A(n) is an aerodynamic admittance...
The applicable wind speeds for the United States and some tropical islands specified in the wind speed maps are three-second gusts at 33 feet above ground for Exposure Category C. In the model codes that preceded the IBC (the National Building Code. Standard Building Code, and Uniform Building Code) and versions of ASCE 7 prior to 1995, wind speeds were shown as fastest-mile winds, which is defined as the average speed of a one-mile column of air passing a reference point. While the designated 3-sec gust wind speed for a particular site is higher than values on the fastest-mile map, the averaging times are also different. The averaging time for a fastest-mile wind speed is different for each wind speed, while the averaging time for the 3-sec gust speeds varies from 3 to 8 sec, depending upon the sensitivity of the instruments. Wind load provisions of UBC 1997 are based on the ASCE 7-88 standard with certain simplifying assumptions to make calculations easier. The design wind speed is...
Water to keep the footing evenly moist to a 3-inch depth. Once the arena is at a moisture that is suitable for your riding purpose, use a garden-supply store meter to determine that moisture content and strive to achieve that moisture on subsequent waterings. Water an arena as you would a garden. It does not need to be flooded, nor does just wetting the top fraction of an inch do any good. Give it a good watering with plenty of water in frequent, short periods. The dry spells are for water absorption into the footing material(s). In fact, leave about four hours or overnight before using the arena again to allow moisture to soak in. Once the correct moisture is achieved, subsequent waterings will only be needed to remoisten the topmost surface that will be drying faster than the footing underneath. The water schedule will naturally depend on season (air temperature), wind, and sun exposure of outdoor arenas and the indoor arena air temperature and moisture level. Watering when the...
Materials and technologies are also increasingly common in residential high-rises, which take advantage of green construction methods developed for commercial buildings. Builders have made great strides in reducing environmental impact by using harvested lumber and recycled materials, the installation of non-toxic and energy-efficient insulation systems, and the selection of building sites that take maximum advantage of solar and wind power as well as access to public transportation. It is worth noting that one of the most popular types of urban construction converting industrial buildings into residential properties is intrinsically green. Recycling and renewing old structures are among the best ways to minimize waste and preserve resources.
In both the traditional vernacular and the contemporary approach, the strategy is climatic. Passive cooling strategies require that the use of renewable energies is maximized, in this case, the Pacific trade winds, which blow onto the promontory site from the sea. Piano's 'cases', which face south-south-east, are made of iroko wood, with laminated wood elements up to twenty-eight metres high supporting horizontal curved slats that allow free air circulation between themselves and the louvered inner skin. The louvres are computer-operated, designed to open automatically to their full extent when there is a gentle breeze, and begin to close if wind speed increases. If the wind shifts direction, ventilation is through the much lower front of the building, evacuating through the top of the double skin. The design evolved under wind tunnel testing and computer simulations carried out by Ove Arup and Partners and CSTB (Centre Scientifique et Technique de Batiment), but only the building's...
Wind energy is translated into the unlikely rotation of a mechanical platform embedded in the courtyard of Munich's building department administrative building. A turbine placed atop the building tower captures wind energy that is used to power a turntable of landscape, lying within the protected confines of the building's walls. A connection, however abstract and perhaps invisible, is made between the force of wind and the slow rotation of the platform. The effect of this unlikely relationship is a surreal and unprecedented landscape condition A PORTION OF A COMMON COURTYARD DESIGN BECOMES A MOVING IMAGE OF CONSTRUCTED NATURE, WHERE TREES, PAVING, LIGHTING, AND BENCHES ALIKE REVOLVE AS IF ON DISPLAY. 1 The rotating ring of landscape rests flush with the surrounding lawn and paved courtyard. 2 As the ring rotates, this composition revolves in and out of alignment, carrying trees and visitors alike. 3 A turbine placed atop the building tower captures wind energy that is used to rotate...
On an ethical level, the built systems necessary to accomplish this were to be lessons in themselves, demonstrations of solar and wind power, waste recycling and water conservation, requiring the responsible participation of students and staff to close the consumption circle. On a pedagogical level, knowledge was recycled via electronic loops, which gathered it from the world and disseminated it through the world.
Building performance included the stipulation that energy use must be less than 105kWh m2 yr. The overall plan aims to obtain 100 of the community's electricity from renewable sources such as a 2MW wind turbine and 120 m2 of PVs (see Fig. 15.2). There is a highly disciplined transport policy for the site. Streets are car free and parking is limited to one space per dwelling. However, the real innovation is the provision of a pool of electric vehicles charged by wind power to enable the residents to reach the city centre. A neighbourhood garage provides natural gas biogas for alternative fuel cars.
Exterior vents supply the waterwalls with fresh air which is drawn down by the falling water, like in a natural waterfall, which is then filtered, moistened and blown out by the water into the interior at a wind speed of 3 m sec. The system cools the building in the summer and heats it in the winter. Exterior vents supply the waterwalls with fresh air which is drawn down by the falling water, like in a natural waterfall, which is then filtered, moistened and blown out by the water into the interior at a wind speed of 3 m sec. The system cools the building in the summer and heats it in the winter.
The building's lateral loads were originally taken by the mass brick exterior walls as a box system with some interior masonry walls being used to act as bearing and shearwalls. These augmented the exterior walls and added strength due to the building's ell shape. The design basic wind speed of 120 mph for Norwich produced the greater building design lateral loading as opposed to the seismic lateral requirement. Connecticut is in a moderate seismic zone, with the State's ground accelerations per Code analysis producing less forces in the building's lateral resisting structural elements. Two factors contributed to this result. First, the building's height (5 stories for the Wauregan and 6 stories for the Clarendon Annex) presented a substantial area for wind loads, and second, the light weight wood floor did not contribute substantial mass in the earthquake's lateral load formulas. The wind's total base shear was thus in excess of that produced by seismic analysis. It is worth noting...
The Turbine Tower section models showing thermal response of building in summer (left) and winter (right). On the winter model, wind turbines can be seen sitting between the aerodynamically designed office building and the service The Turbine Tower section models showing thermal response of building in summer (left) and winter (right). On the winter model, wind turbines can be seen sitting between the aerodynamically designed office building and the service
The concept of sustainable development, and associated practices such as sustainable construction, lend themselves to investigation via the sketchbook. It is possible to use freehand drawing to explore aspects of modern green design, be it the use of solar energy, wind power or natural ventilation. Conversely, most of the buildings constructed before the Industrial Revolution utilised local renewable energy sources, building materials were from the immediate locality, transport and farming practices relied on human and horse power, and cities were located where natural resources demanded. There was little or no importation of energy, food, water or materials, and since there was scarcity all round, there was a great deal of reuse and recycling. In this there are lessons for the future, which can be recorded and understood through freehand drawing. So sketching can help reveal best green practice, whether old buildings or more recent examples are employed.
India has been divided into six wind zones. Each wind zone has a specific basic wind speed. These basic wind speeds have been used to compute design wind pressures. A proper wind zone should be selected for the site of a building. For ready reference, wind zones and basic wind speeds of some important cities and towns are given in the table 4.5. Wind Speed Basic Wind Speed (m s)
Wind-tunnel testing of buildings has been an offshoot of aeronautical engineering, in which the flow of wind is duplicated at high altitudes. The tunnels for testing airplanes are designed to minimize the effects of turbulence, and as such, they do not duplicate atmospheric boundary layer or wind turbulence. This is because majority of airplane flights, except for brief periods of landing and takeoff, occur at a height well above the boundary layer. Building activity, on the other hand, occurs precisely within this atmospheric boundary layer, characterized by a gradual retardation of wind speed and high turbulence near the surface of the earth. Therefore, for testing of buildings, aeronautical wind tunnels have been modified and entirely new facilities have been built to reproduce turbulence and natural flow of wind within the boundary layer. 1. The natural atmospheric boundary layer has been modeled to account for the variation of wind speed with height. Boundary-layer wind tunnels...
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 an adjunct to buildings but a concept patented by Altechnica of Milton Keynes demonstrates how multiple turbines can become a feature of the design. Figure 5.8 Flying Electric Generator system (courtesy of Sky Windpower Corporation artist, Ben Shepherd) Figure 5.8 Flying Electric Generator system (courtesy of Sky Windpower Corporation artist, Ben Shepherd) One of the most ambitious wind projects has emerged from Australia with the idea of a power station in the sky. High-altitude winds have high velocity and are constant. The idea is to install flying wind generators at 15,000 feet to harvest this energy. 'High altitude wind power represents the most concentrated flux of renewable energy found on Earth'. Depending on location, flying generators could be 90 efficient, which is well over three times that of...
CHP has advantages when used in conjunction with solar energy and wind power. Large plants between 100 and 300 MW of electrical capacity are flexible, having the ability to change their mode of operation from producing electricity alone to delivering both electricity and heat in varying proportions. This means that it can adjust its mode according to how much electricity is being provided from renewable sources. CHP is reliably available at times of system peak, being immune to the vagaries of wind or sun. It is therefore ideal for complementing renewable technologies.
A wind velocity having a specific mean recurrence interval. Mean recurrence intervals of 20 and 50 years are generally used in building design, the former interval for determining the comfort of occupants in tall buildings subject to wind storms, and the latter for designing lateral resisting elements. The originally parallel upwind streamlines are displaced on either side of the building, Fig.1.5. This results in spiral vortices being shed periodically from the sides into the downstream flow of wind, called the wake. At relatively low wind speeds of, say, 50 to 60 mph (22.3 to 26.8 m s), the vortices are shed symmetrically in pairs, one from each side. When the vortices are shed, i.e., break away from the surface of the building, an impulse is applied in the transverse direction. At low wind speeds, since the shedding occurs at the same instant on either side of the building, there is no tendency for the building to vibrate in the transverse direction. It is therefore subject to...
Model studies can provide reliable estimates of pedestrian-level wind conditions based on considerations of both safety and comfort. From pedestrian-level wind speed measurements taken at specific locations of the model, acceptance criteria can be established in terms of how often wind speed occurrence is permitted to occur for various levels of activity. The criterion is given for both summer and winter seasons, with the acceptance criteria being more severe during the winter months. For example, the occurrence once a week of a mean speed of 15 mph (6.7 m s) is considered acceptable for walking during the summer, whereas only 10 mph (4.47 m s) is considered acceptable during winter months.
Reduce the impact on peak cooling loads in the summer. In addition, natural gas or oil is not used for heating on-site. The building is all-electric and the energy provider is currently investing in renewable wind energy in Iowa. While there are no current contracts in place for purchasing green power for the building to date, they will be accommodated in the future. The heat pump system is zoned to allow for a dynamic system that can accommodate fluctuating use of space throughout a day or week. Fourth, for supplemental heating in winter, the main gathering space can be heated with a corn-burning stove furnace. In the coldest of Iowa weeks, the furnace would use approximately one bushel of shelled corn per day. This corn is obviously a renewable resource and is demonstrating to the public that there are options to traditional fossil fuel heating and cooling systems.
Proposals by the Crown Estate to build 250 wind turbines off the Lincolnshire coast, which form part of the world's largest programme of offshore wind farm development, aim to meet some of the objections to such turbines being located inland in sensitive areas of natural beauty. According to UK Government Minister Stephen Tims, 'These wind farms will not only put us on the path to providing 10 per cent of energy from renewable sources by 2010, but they will also help us to meet our aim of generating 20 per cent of our energy from renewables by 2020.' (Planning, 4th July 2003 and 9th April 2002). Projects like this are part of the UK energy strategy, but they are thought to be overoptimistic according to the report State of the Nation 2003 (quoted in Planning, 11th July, 2003). Figure 1.3 Wind farm, Bellacorick, County Mayo, If that report's prognosis for the parlous Ireland. The wind farm is sited state of UK energy supplies when North on 'cut-away-b0g' Sea gas runs out early this...
Gas and oil produce lower emissions to the atmosphere for each unit of delivered energy than electricity, making electricity, in general, the least preferred option for heating. A zero-CO2 emission option is to use active solar energy for hot water, wind energy and or biofuels such as woodchip, waste, straw or paper. Renewable energy technologies are dealt with in Chapter 11.
All energy sources are derived from the sun, with the exception of geothermal, nuclear, and tidal power. When the sun heats the air and the ground, it creates currents that can be harnessed as wind power. The cycle of evaporation and precipitation uses solar energy to supply water for hydroelectric power. Photosynthesis in trees creates wood for fuel. About 14 percent of the world's energy comes from biomass, including firewood, crop waste, and even animal dung. These are all considered to be renewable resources because they can be constantly replenished, but our demand for energy may exceed the rate of replenishment.
The autonomous house as envisaged by Robert and Brenda Vale, with its own solar panels, wind turbine, rainwater filters and composting toilet, is not without maintenance needs so how are they to be met Some of the questions appropriate to ask in relation to the automated building are equally applicable here. How sophisticated are the systems For how long will parts be available
Leidsche Rijn, a new growth district in Utrecht, incorporates a mixed-use design and a balance of jobs and housing (thirty thousand dwelling units and thirty thousand new jobs) as well as a number of ecological features. Much of the area will be heated through district heating supplied from the waste energy of a nearby power plant, a double-water system that will provide both potable and recycled water for nonpotable uses and stormwater management based on a system of natural swales (what the Dutch call wadies). Higher-density uses will be clustered around several new train stations, and bicycle-only bridges will provide fast, direct connections to the city center. Homes and buildings will meet a low energy standard and must use certified sustainably harvested wood. At Kronsberg, a host of green urban elements are integrated into this new ecological district, including three wind turbines, solar panels, district heating, onsite stormwater collection, green rooftops, and green...
Winds are usually weakest in the early morning and strongest in the afternoon, and can change their effects and sometimes their directions with the seasons. Evergreen shrubs, trees, and fences can slow and diffuse winds near low-rise buildings. The more open a windbreak, the farther away its influence will be felt. Although dense windbreaks block wind in their immediate vicinity, the wind whips around them to ultimately cover an even greater area. Wind speed may increase through gaps in a windbreak. Blocking winter winds may sometimes also block desirable summer breezes. The wind patterns around buildings are complex, and localized wind turbulence between buildings often increases wind speed and turbulence just outside building entryways.
The most pressing case for a hard barrage in the UK is located in the Thames estuary. It is a situation identified by the Met Office as being the most vulnerable in northern Europe to severe storm surges up to and beyond 2080. Especially threatened would be the proposed Thames Gateway housing development. A tidal barrage would also be able to generate considerable quantities of electricity via underwater turbines and 5 MW wind turbines along its apex (see Fig. 11.10).
However, the annual energy performance of a theoretical urban model loosely based on the Parliamentary Building geometry was simulated using real time UK climatic data, and proved that in the UK winter wind power and summer photo-electric generation complemented each other excellently. This enabled the fan run times to be reduced to the point where the total energy consumption became 27kWh m2 floor area y. If additional areas of high-efficiency photovoltaic cells were incorporated on the sloping roof surfaces, taken over a year's duration, this design could produce as much energy as it consumed. As PV prices drop and efficiencies rise, it will be increasingly viable to build low rise zero energy urban offices.
While I continue to work in the larger-scale landscapes of forests, I have also had the opportunity to test out and apply the design principles in other fields of design. The latest of these is wind turbine development. This reflects one of the current concerns of landscape planning and design and also demonstrates the need to develop new applications. Ten years ago, wind turbines were not important but now they have a major impact on many scenes.
These communal spaces in mid-season, when heating and cooling loads are lowest. Each room has tilt turn opening windows, allowing most rooms to be naturally ventilated and effectively allowing a mixed-mode ventilation option. Rotating wind-driven cowls track away from the prevailing wind down to wind speeds of 2m s, ensuring flow reversal never happens and that a constant negative pressure is maintained at the head of each stairwell.
Although the water in the rills appears to flow into the fountain, there are actually two separate circulation systems. Similarly, while it appears that the eight large bronze vessels carry a large quantity of water, the reservoir tanks are in fact below ground. One ingenious feature of the system is that it adjusts according to weather conditions. An anemometer attached to one of the lamp columns measures wind speed and can initiate a progressive shutdown. On calm days everything will work, but as the wind speed starts to rise, the flow from the spouts will be reduced and the height of the jets is reduced. On really windy days the spouts and the fountains cut out altogether although water will still flow along the rills, thus overcoming the risks and inconvenience of blown spray which is so often a problem in the British climate.
The unaided volume of airflow through a building depends on the number, position and orientation of openings, the difference in temperature between inside and outside, and the wind velocity. The wind creates pressure differences that drive air into a building on the windward side and out on the leeward side. Indoor activities create thermal gradients as warm air is 'lighter' than cold air and will tend to rise and leave at high level to be replaced by air entering at low level - the so-called 'stack effect'. These forces of wind pressure and gravity may act together or separately and can, if well understood and properly managed, be a driving force for NV. However, not all buildings, or parts of a building, will require the same approach, and strategies need to reflect outside air quality, orientation, location, seasonal effects and usage patterns, including temporary loads. Variability in wind regimes and uncontrolled pressure differentials mean that the task is non-trivial even in...
When considering the dynamic response of structures to wind there are two broad categories of mechanisms that may occur. Short-term variations in wind speed produce turbulent flow, or buffeting, that may result in resonant response of the structure. Excitation may also occur in smooth flow and these responses are categorised as aerodynamic instabilities.
Convenient source of energy for illumination, heating, power equipment, and electronic communication. Electricity is not usually generated on the building site. Small generating units powered by internal-combustion engines, water, sun, or wind have generally been considered expensive to buy and maintain, of limited capacity, and less reliable and efficient than central generating plants, although this is changing. Local energy generation can be noisy or smelly. The water levels, wind speeds, or sunlight levels used for local energy production tend to fluctuate and may be unable to generate a steady alternating current (AC). Private generating systems have been relegated to use as standby generators to keep critical buildings electrified during power failures, or as generators installed in large building complexes as part of a total energy system. As fuel prices rise, we are examining fuel efficiency and use more closely. Techniques for generating and storing energy are advancing, and...
2, Windy areas have a greater evaporation rate and may require more water. To avoid disruption from air movement, timers should be set to irrigate when the wind speeds are minimal, or heads with lower trajectories and larger orifice sizes may be used 4. Early morning hours are usually the best time to water because wind speeds are typically low. evaporation is at a minimum, and plant leaves do not remain wet for long periods of time. Early morning hours are usually the best time to water because wind speeds are typically low, evaporation Is at a minimum, and plant leaves do not remain wet for long periods of time.
Air movement in the outdoors varies over a broad range. On the occasional summer day when there is little or no wind, a sweltering, suffocating, claustrophobic sensation is felt. A light breeze has a pleasant, exhilarating, cooling effect. With increasing wind velocity, convective and evaporative heat losses from the skin can become excessive, particularly if the weather is cold. At very high wind velocities, chilling of the body is extreme respiration may become difficult solid objects are picked up and carried by the wind and structural damage to trees and buildings is likely.
Allow poor and lower middle-class people to have a healthy, attractive home, with lower utility costs and more flood-proofing than conventional housing. Renewable energy systems using the ubiquitous solar and wind energy of the planet are powering many poor villages in the developing world, helping to provide education and healthcare in resource-poor environments.
Set on a 1.5 hectare site on a volcanic cliff overlooking the sea on the northern coast of Puerto Rico, this house for a couple and their three children is spedfl ally designed to resist frequent hurricane force winds. The house is approached from the roof side. The architect says that the house is to be seen to a certain am as an outpost and as such has two adjustable wing-mounted, horizontal-axis wind turbine assemblies projecting from the upper deck to take advantage ol the m ly constant wind from the north. Rainwater is stored in cisterns beneath the living spaces and vents provide for natural ventilation. Emphasizing the fortified aspect(fl house, the lower walkways and decks are hinged to rotate up and act as storm shutters, protecting the glazing as well as locking the house up tight. To be madefl ly with cast-in-place concrete, the house will have sealed or waxed concrete, local veneer plywoods, stainless steel and plaster for the Interior finishes. The floor art the house is...
Future Systems, a design firm from London, used computational fluid dynamics (CFD) analysis in a particularly interesting fashion in its Project ZED, the design of a multiple-use building in London (1995 figure 14.4). The building was meant to be self-sufficient in terms of its energy needs by incorporating photovoltaic cells in the louvers and a giant wind turbine placed in a huge hole in its center. The curved form of the fa ade was thus designed to minimize the impact of the wind at the building's perimeter and to channel it towards the turbine at the center. The CFD analysis was essential in improving the aerodynamic performance of the building envelope.
ABSTRACT Bayon temple, Angkor, consists of dry-masonry structures made of sandstone. Strong wind in the rainy season is suspected as one of the causes for its progressive deterioration. Since 2003, micro-tremor has been measured at most of the tower-type structures and the continuum-equivalent elastic modulus was found to be 1 9 to 1 27 of that of the sandstone specimen in laboratory tests. In 2006, micro-tremor was measured at libraries in Bayon temple and the similar reduced equivalent modulus was also obtained for these frame-like sandstone-dry-masonry structures. This extremely low elastic modulus implies the inadequacy of continuum modeling for bearing capacity of dry-masonry structures. Then the Discontinuous Deformation Analysis was applied to safety evaluation of the library against wind load. It was an illustrative example however, the evaluated safety margin for the wind velocity of 40 m s is about two.
A phenomenon experienced on a number of cable-stayed and arch bridges in recent years, vibrations have been witnessed when low wind speeds combine with light rain. Stays within polyethylene ducts are known to be the most susceptible to this effect. Rain-wind oscillations of the stays usually occur in the wind speed range of 7-20 m s. Below this range the rain rivulets do not form, while above this range the rivulets tend to be blown off by the wind before excitations occur. It has been suggested that there is negligible risk of rain-wind oscillation when Sc 10 while rain-wind vibrations have been observed at frequencies between 1 and 3 Hz.
Where D horizontal force N , S area m2 , C resistance factor, p density kg m3 , V wind velocity m s . For wind velocity of 40m s, (1) gives about 10,000 N m2, which is less than a half of the evaluated bearing capacity of the first slide at 20,117 N m2. Then the safety margin for the wind load corresponding to wind velocity of 40 m s is more than twice.
Energy consumption and internal comfort monitoring include measurements of the air temperature in the office space, atrium and the two passageways humidity levels in the office space electrical loads gas usage wind speed and direction. The activation of the automated solar facade vents and the upper window lights are recorded. This will allow the whole performance of the building to be assessed and the success of the design to be determined (see Figure 10.14).
A small vertical axis wind generator is mounted on the boiler flue, providing some electricity to run lighting. The high electrical loads needed to run the conference IT system and high-powered audio visual system will be provided by the Earth Centre's mains electrical grid, with a large proportion supplied by the new PV canopy designed by Feilden Clegg Bradley (see Chapter 11).
The most important objective when laying out sprinklers is the even distribution of water. Sprinklers that produce different precipitation rates should not be used In the same zone Sprmkler-to-sprlnkler dimensions should be based on manufacturer's recommendations, with deviations for wind velocity. Spacing for triangular and square patterns varies with brand and model.
Consider a building subjected to lateral wind loads. Although wind loads are dynamic, in typical design practice, except in the case of slender buildings, wind loads are considered as equivalent static loads. The variation of wind velocity with time is taken into account by including a gust factor in the determination of wind loads. Therefore, for a given set of wind loads, there is but one unique solution.
The effect of lateral load on tall structures is similar to gravity load on cantilevers, such as balconies. Tall structures act like cantilevers projecting from the ground. Lateral load generates shear and bending that may be presented in respective shear and bending diagrams as in a cantilever beam. Yet there are important differences, The shear and bending diagrams for buildings are usually global, for the entire system rather than for individual elements like beams. For example, global bending (overturn moment) causes axial tension and compression in columns, and local shear and bending in beams. Further, lateral wind and seismic loads are non-uniform. Wind force increases with height due to higher wind speed and reduced friction. Seismic forces increase with height in proportion to increasing acceleration (acceleration increases with height due to increased drift). However, shear increases from top to bottom since the structure at each floor must resist not only the force at that...
Sidewall curtain material is often translucent and so provides light even when closed (Fig. 16.17). Another option for light and air entry is a mesh material rather than or in addition to a solid curtain material. Greenhouse shade cloth or similar material may be used. Shade cloth is a woven polypropylene fabric that is selected to block from 5 to 95 of the light striking it. Therefore, a portion of light is blocked for reduced glare from direct light and heat buildup. The mesh fabric reduces wind speed of air entering the arena through the large opening for benefit on windy or cool days when fresh air exchange is desirable, but reduced air velocity is more comfortable for arena occupants. Mesh no more than 80 weave for light blocking is recommended to allow adequate airflow even during the coldest weather, while providing adequate light blockage.
I am indebted to the researchers and construction professionals who readily gave permission for the inclusion of their work in the text. These include Dr Koen Steemers of Cambridge Architectural Research, Arup Associates for BedZED diagrams, Christopher John Hancock for the images of Malmo, Jeremy Stacy Architects for the Council Offices, King's Lynn, Fielden Clegg Bradley for the National Trust Offices, Swindon, XCO2 for the triple helix wind generator image and Pilkington plc for the image of Herne Sodingen government training centre. I also owe my thanks to Dr Randall Thomas of Max Fordham and Partners and Robin Saunders of the Department of Mechanical Engineering, Sheffield University for reviewing the manuscript and giving me the benefit of their expertise in the sphere of renewable energy. I must also record my thanks to my wife Jeannette for her sterling work in making up for my deficiencies in proofreading. Finally, my special thanks are due to Sir John Houghton for allowing...
The tower consists of four lobes or 'petals' which direct the wind into a central void containing wind turbines. Wind velocity tests indicate that air flow at the core of the building would be multiplied four-fold by the configuration of petal plan. This would be sufficient to power several vertical axis turbines which would be almost silent. At the same time the floor plates are designed to provide maximum views whilst optimizing daylight (see Fig. 15.11).
The roof improve natural ventilation at low wind speeds. Mechanical ventilation must be used when there is no wind. Depending on the wind direction and the geometry of the surroundings, curved roofs can set up complex patterns of positive and negative wind pressures, which may require wind tunnel tests.
Section model studies are performed for prismatic (two-dimensional) structures such as long-span bridge decks. A rigid model is mounted on a dynamic test rig consisting of a system of springs to model the properties of the structure. Measurements are made to determine the dynamic response due to mechanisms such as vortex shedding and the wind speeds for the onset of aerodynamic instabilities such as galloping and flutter. The section model itself is designed using materials such as balsa wood, carbon fibre sheet and steel sections such that it accurately represents the scaled mass in conjunction with the lowest torsional and bending frequencies of the prototype. Sectional models should include handrails, parapets, guide vanes, maintenance gantry rails, stay pipes and all other non-structural appurtenances that have the potential to influence the aerodynamic behaviour of the deck. Where these items are too small to be modelled to scale aerodynamically equivalent representations may be...
The buckling behaviour and wind load assumptions of the structure will have to be investigated more deeply, as the results are not in line with the 80 year life span of the tower. One critical point is the lack of the 50-year wind velocity at the locality of the tower. Shielding of members in an open circular framework is another issue that requires further research. The disregard of any reduction factor for shielding (due to the lack of suitable specifications) certainly effectuates a too conservative assessment of the structural safety of the tower.
Horizontal-axis underwater turbines are the favoured technology for offshore tidal currents. They are similar to wind turbines but water has an energy density four times greater than air, which means that a rotor 15 m in diameter will generate as much power as a wind coincides with the bottom of the market price. This is a problem experienced by Denmark when its domestic market has no demand for the excess wind power, and it has to export to Norway and Sweden in a buyers' market.
Wind loads were based on the DIN 1055-4. The code calls for the wind velocity measured 10 m above ground with an exceeding probability of 1 50. Only the 5 year wind velocity was available for the locality of the tower. Based on various reference material (Schueller 1981), the wind velocity was extrapolated rather conservatively with the factor 1.39. The resulting reference velocity pressure for 50 years was thus determined as 0.32 KN m2.
Anemometer A device for measuring wind speed. These instruments and the information they produce assist in determining water needs of plant material. They usually consist of cuplike devices held on arms arranged radially around a point where they spin in the wind, allowing recording of speed through a wire.
Counting wood burned for fuel and electricity, as well as large hydroelectric projects, wind farms and biofuels, renewables currently account for about 12 of total US energy use.129 Many state legislatures are beginning to consider laws that would require electric utilities to produce 15 to 25 of their electricity from renewable sources within 20 years, by 2025 to 2030.130 A newly formed group encourages government programs to help America's farms, forests and ranches generate 25 of the country's total energy needs from sun, wind and biofuels by 2025.131
Solar energy comes in four useful forms. First, by providing the energy for photosynthesis, the sun maintains life by producing food and converting carbon dioxide into oxygen. Photosynthesis is also necessary for the growth of wood, and indirectly for fossil fuels, which were once living plants and animals. Second, natural daylight provides illumination both outside and inside buildings. The third form is provided when photovoltaic cells convert sunlight directly into electrical energy, and the fourth form, thermal energy, is used for space heating, domestic hot water, power generation, distillation processes, and heating of industrial processes. You could even include wind power as a fifth form, since the sun's heat drives the wind. Solar heating is primarily concerned with the sun's thermal energy, but solar designs have implications for photovoltaics, lighting, and even photosynthesis as well.
The roof of the addition and the front porch support a 2,300-square-foot, 26.4-kW photovoltaic array that produces an average of 30,500 kWh of power annually. The design concept is based on the addition of a wind turbine to provide the balance of the electricity demand. The array is connected to the regional power grid, to which electricity has been flowing in times oflocal surplus.The heating and cooling energy is reduced through the use of a groundwater well,
Biofuels account for 82 of world renewable energy sources. Most of the hydro accounts for 15 and wind power 2.5 . Of the 3.0 Million Tonnes (MT) of oil equivalent of primary energy use accounted for by renewables, 2.2 MT was used to generate electricity and 0.8 MT to generate heat. Global renewable energy use grew by 8 in 2000 and has doubled in the last seven years. It accounted for 2.8 of electricity generated in the UK in 2000.
We have it in our power to change this situation. We can reduce substantially the energy needed by our buildings. We can meet much of this need with solar and wind energy, both of which are renewable, nonpolluting, and available on the site itself. In many instances, we can build on land that has been recovered from abusive practices of the past such as contaminated industrial sites, demolished tenement apartment buildings, and land on which poor agricultural practices have led to extensive soil erosion. We can build with wood from certified forests, ones that are harvested and replanted in such a way that they will produce wood forever. We can build with wood recovered from old buildings that have been taken down. In each of these examples, we are building in such a way as to pass on to future generations the means to build in a similar fashion.
The Port Kembla installation has a peak capacity 500 kW and an output of over 1 GWh year which is fed to the grid. The economics of the system compare favourably with solar energy and wind power. With refinements to the system the unit price is expected to outclass all competitors. A single installation of this kind has the potential to generate 1000 kW which would power 2000 homes (Caddet). Several sites in Australia such as the Bass Strait and Southern Australia coast have the wave potential to generate up to 1 MW per unit.
Green buildings (as well as you and I) have the option of buying some or all of their electricity from a green power provider. In this context, green power is renewable energy produced somewhere else and then transmitted to the project site (figuratively). There are dozens of such suppliers in the US, most of which are wholesalers of wind power, some solar power and some biomass, geothermal or low-impact hydro facilities. My own local utility, Tucson Electric Power, sells two packages of GreenWatts power, one 99 wind and 1 solar, the other 90 wind and 10 solar (at a 20 premium). Tucson Electric Power operates one of the largest photovoltaic (solar electric) power plants in the country, a 5.1-megawatt array capable of producing 7.5 million kilowatt-hours per year of electricity, enough to power 500 Arizona homes.61 I purchase 2,400 kilowatt-hours per year of this power, about 20 of my annual use, for an annual premium of 186, or about 7.75 cents per kilowatt-hour. For commercial users,...
The central argument between such advanced systems and 'low tech' ones is over what is referred to as capital energy cost, that is, the total energy used in all the stages of a material's manufacture, from raw material to finished product. Even framing the problem is contentious should we be arguing about how this capital energy cost is to be repaid, or about whether the energy capital should have been spent in certain ways in the first place Can even rapid repayment with interest (clean energy back into the grid via photovoltaics or wind turbines) ever justify a more environmentally expensive method when less expensive ones are available Every unit of polluting energy used in the making of, in
Factors include basic wind speed, exposure (urban vs. open terrain, for example), height of the structure, the importance of the structure (i.e., consequences of failure), and gust-effect factors to account for the fluctuating nature of the wind and its interaction with the structure.
By making turbine blades stronger and lighter, carbon fiber technology has helped wind power become the world's fastest growing clean energy source. Now, that same technology can help you conserve energy in your buildings. CarbonCast precast concrete wall systems and cladding use ultra-strong C-GRID carbon fiber grid for secondary reinforcing and C-GRID trusses for shear transfer. C-GRID is non-corrosive so it requires less concrete cover, giving you thinner and
The Analytical Procedure includes figures and tables for wind speed, exposure, building form, roof slope, enclosure, dynamic behavior and topography. q 0.613 I Kz KztKdV2 V wind speed in mph m s Importance factor 1 (for rigid structures 1 Hz, usually 10 stories) (for fabric structures, depending on form, etc) (ASCE 7 figures and tables) (windward walls, varies with height z) (side walls - constant - based on height h) (leeward walls - constant - basad or, heigh h) (windward and flat roofs) (leeward roof) SOE 7 Fig. 6-5, based on highest opening) pen structures) (enclosed buildings) (Velocity pressure in psf) (SI units velocity pressure in Pa) (IBC Fig. 1609 wind speed map or local data) (IBC table 1604.5) (all structures not listed below) (essential facilities hospitals, police and fire stations) (facilities presenting hazards to human life) (agricultural and some temporary facilities) (ASCE 7 Fig. 6.4) Exposure C wind pressure for 10' to 100' height and 85 to 150 mph wind speed...
Solar collectors are one of several renewable technologies that together make a solar building. It is essential that, from the earliest design stage, there is a symbiotic relationship between active solar and PVs, heat pumps and possibly small-scale wind turbines. 'Integrated design' is one of the slogans of the new millennium.
Neoprene gaskets work best when they are compressed within the joint, normally on the back side of the panel edge profile. A simple compressible gasket using timber edging pieces with GRP panels was developed for Teesside Polytechnic (architects Basil Spence & Partners) (Fig. 3.21), for use with panels I m x I m. A more complicated gasket joint was developed for Mondial House (Hodge, 1968) (Fig. 3.22), which uses a combination of a neoprene baffle, a PVC back channel and a strip sealant under compression from a back plate.The joint was tested successfully by Yarsley Laboratories to BS 4315, simulating I 8.75 cm of rain per hour at a wind speed of 56-64 km h.This very sophisticated joint combines the principles of an open-drained joint with that of a labyrinth joint. As a result of this experience at Mondial House, Anmac Ltd developed its own 'patented'two-stage mechanical joint called LSB. This had the advantage that the jointing product is under compression and hidden from...
Site because of high wind speeds coupled with their own light weight, and the size and number of fixings for a large panel need careful consideration. Although GRP as a material is relatively tough, surface protection during transport and erection on site to avoid surface scratching may be recommended (Fig. 3.26).
We're seeing the world's largest companies make major commitments to energy technology and a wave of other innovations that will affect building design. A good example of this is the 1.5 billion investment Eco-Imagination campaign launched by General Electric's (GE) CEO Jeffrey Immelt in 2005, well before the current wave of eco-inspired corporate concern. The campaign includes major investments in solar and wind energy technology as well as in water desalination. In addition GE set a 30 greenhouse gas (GHG) intensity reduction goal by the end of 2008, along with a 1 absolute reduction by the end of 2012. GE has also set an energy-efficiency improvement goal of 30 by the end of 2012. Progress will be measured against a 2004 baseline.143
Since the completion of the Eco-cabins in 1991, over 5000 people (mainly schoolchildren), have occupied them for a week-long learning experience. During their stay, they learn about managing renewable energy sources, conservation of energy and water, dealing with sewage effluent, composting techniques and environmentally benign ways of growing food. The Eco-cabins themselves are two self-contained residential units where the electricity supply, the water supply, the waste system and the heating system are all independent standalone systems operated and studied by those who stay in them. Each cabin receives an equal share of the generated energy, which is monitored on display boards inside the cabins. The display board gives information of the battery voltage, input and output currents, both instantaneous and cumulative, wind speed,
Typically, aeroelastic measurements are carried out at several wind speeds covering a range selected to provide information on both relatively common events, such as 10-year wind loads, which may influence the serviceability and occupant comfort, and relatively rare events, such as 100-year winds, which govern the strength design. The modeling of
The concept of using a satellite radar altimeter was established by Skylab in 1973. The satellite Seasat was operational for a few months in 1978 and was the first to give global coverage. The prospect now is for two satellites to be operational at any one time. The higher the waves in the footprint of the satellite radar, the more spread out is the time of arrival of the return pulse. Adjusting the height of the return pulse to a constant value, the slope of the leading edge gives a measure of the significant wave height. Wind speed is indicated by the back scatter of the signal. Early radars did not permit the wave period to be measured but later synthetic aperture radars should fill this gap.
On-site generating units, whether powered by internal-combustion engines, water, sun, or wind, are generally expensive to buy and maintain, are of limited capacity when compared with the capacity we have grown to expect of our electrical systems, and are less efficient and reliable than central generating plants. They may also be noisy and smelly they may be unable to generate steady alternating current and they may not be able to provide electricity when water levels or wind speeds are low, when clouds are present, or when they break down.
Away from the earth's surface the pressure system is relatively stationary as the pressure gradients are balanced by the earth's centripetal and Coriolis accelerations. Nearer ground level significant drag is experienced due to the surface roughness resulting in disturbances to this pressure system. The effect of surface roughness is to reduce the wind speed near the ground, to cause the wind to flow in directions that are not parallel to the isobars and to produce turbulent flow characteristics. mean wind speed
Below The five dresses that formed Hussein Chalayan's Inertia collection finale incorporate within them the dramatic moment of impact of a hypothetical car crashing at high speed. The impact translated into form, the wreckage into decoration. The wind machine catches the model's hair to continue the viewer's association with high-speed travel.
Table 4.6 Design Wind Pressure 'PZ' for Wind Zone-1 (Basic wind speed 33 m sec) Table 4.6 Design Wind Pressure 'PZ' for Wind Zone-1 (Basic wind speed 33 m sec) Table 4.7 Design Wind Pressure 'PZ' for Wind Zone- II (Basic wind speed 39 m sec) Table 4.7 Design Wind Pressure 'PZ' for Wind Zone- II (Basic wind speed 39 m sec) Table 4.8 Design Wind Pressure 'PZ' for Wind Zone- III (Basic wind speed 44 m sec) Table 4.8 Design Wind Pressure 'PZ' for Wind Zone- III (Basic wind speed 44 m sec) Table 4.9 Design Wind Pressure 'PZ for Wind Zone -IV (Basic wind speed 47m sec) Table 4.9 Design Wind Pressure 'PZ for Wind Zone -IV (Basic wind speed 47m sec) Table 4.10 Design Wind Pressure 'PZ' for Wind Zone- V (Basic wind speed 50 m sec) Table 4.10 Design Wind Pressure 'PZ' for Wind Zone- V (Basic wind speed 50 m sec) Table 4.11 Design Wind Pressure 'PZ' for Wind Zone- VI (Basic wind speed 55 m sec) Table 4.11 Design Wind Pressure 'PZ' for Wind Zone- VI (Basic wind speed 55 m sec) From table 4.6, it...
A thermostat plus spray taps would have been cheaper than the PV panel and a genuine contribution to energy efficiency. It will always be more cost-effective to use low-energy bulbs, good control, draught-proofing or more insulation than to install PVs or a wind turbine to an existing inefficient building. For new builds, the very best possible standards of energy efficiency and control should be prioritised before add-on technology.
I have left the most difficult issue till last, which is resistance to wind loads. One might assume that building that has stood for many years, possibly centuries, has stood the test of time. While that is not unreasonable for masonry structures with large masses it is more problematic with lighter timber structures that might have been subject to some deterioration, especially if there have been periods of neglected maintenance. Moreover we are aware that climate change will result in higher wind speeds in future, again more of a problem for timber structures rather than masonry. The result is that it might be difficult to demonstrate that an existing structure can cope with the required design loads. Of course, in attempting to do this one will often consider the structure acting alone whereas the frames may have always relied to some extent upon the infill material. It is, of course, possible to use the resistance of infill panels where these are of a construction recognised by...
The building has a 20-kW photovoltaic array on the south roof that produces an equal percent of electricity annually as is consumed by the building's lighting system for the entire year. In addition, Save The Bay is working to partner with others to construct a wind turbine on the site. With an eye toward
By wetness is meant the shipping of heavy spray or green seas over the ship. The bow area is the region most likely to be affected and is assumed in what follows. It may limit a ship's speed and the designer needs some way of assessing the conditions under which it will occur and how severe it will be. To some degree wetness is subjective and it certainly depends upon the wind speed and direction as well as the wave system. In the past it was often studied by running models in waves but it is now usually assessed by calculating the relative motion of the bow and the local sea surface. The assumption made is that the probability of deck wetness is the same as that of the relative motion exceeding the local freeboard. The greater the difference, the wetter the ship is likely to be.
The risk of rain penetration through gaps in a structure is greater when the rain is wind-assisted than in still conditions. The severity of exposure to rain was seen as likely to vary both with rainfall and with wind speed measurements made by Lacy, using rain gauges set in the walls of buildings, showed that the amount of rain driven on to a wall was directly proportional to the product of the rainfall on the ground and the wind speed during the rain. This relationship was used as the basis for the derivation of an index of driving rain which could be used to give relative probabilities of rain penetration. The product of average annual total rainfall in metres and annual wind speed in metres per second provides the annual mean index of exposure to driving rain. Contour maps have been produced showing the annual mean driving-rain index for areas in the British Isles. The wind speed used in the calculation of the index refers to an open, level site, so local correction factors have...
The critical wind speed for vortex excitation is based on the Strouhal number f frequency of vortex shedding d diameter of stay V wind speed. For a cylindrical cable, S is equal to 0.2 which gives the critical wind speed, Vc 5wd, where the natural frequency of the cable.
That even very cold fresh air can be introduced into a horse stall, so that when mixed and tempered with stable air, it no longer has the air speed and chill of a draft. Consider a horse outside and the amount of wind speed it comfortably tolerates, and realize that normal air currents of good ventilation in a stable are of little consequence.
The center is planning to add a Northwind 100 wind turbine, funded by the Massachusetts Renewable Energy Trust. It will be located on a 40-meter monopole tower to the southeast of the building. The turbine will provide Woods Hole with over 100,000 kWh of electricity annually, potentially allowing the center to realize its goal of functioning as a net exporter of energy, meaning that the building will generate more energy than it uses. In effect this means that the facility will essentially be offsetting its neighbors' consumption to a certain degree. The integration of all these energy saving components contributes vastly to the building's overall success as a healthy and productive workplace in addition to a research institution that reflects its conservation pursuits.
The commonly used static wind pressure of 20 psf, as specified by many building codes, corresponds to a velocity of 88 miles per hour (mph) from Eq. 1.4.4. An exposure factor C, of 1.0. a gust factor Q of 2.0, and a shape factor Cp of 1.3 for an airtight building, along with a 20 psf equivalent static pressure p, will give from Eq. 1.4.5 a dynamic pressure q of 7.7 psf, which corresponds, using Eq. 1.4.4, to a wind velocity of 55 mph. For all buildings having nonplanar surfaces, plane surfaces inclined to the wind direction, or surfaces having significant openings, special determination of the wind forces should be made using such sources as the ASCE 7 Standard 1.2 , or the National Building Code of Canada 1.9 . For more extensive treatment of wind loads, the reader is referred to the Task Committee on Wind Forces 1.36 , Lew. Simiu, and Ellingwood in the Building Structural Design Handbook 1.10 , Mehta 1.37 . and Stathopoulos, Surry, and Davenport 1.38 .
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Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.