Home Engineering Sustainable High Rise Buildings in Urban Zones: Advantages, Challenges, and Global Case Studies
Public Perceptions and Driving the Visibility of Renewables on High-Rise Buildings
It seems wind turbines are the most controversial when testing perceptions of the public on renewables. The following section will focus on how this particular technology has been more negatively affected by failing examples of their integration on high-rise buildings.
While ethical theories of public participation and awareness (Devine-Wright 2009) point out to strategies that may improve engagement with microgeneration such as citizen ship, appropriate sitting and operation, local management, the main issue still remains. As opposed to passive measures of ‘static and quiet’, renewable microgeneration systems in reducing the carbon footprint of the urban environment, the tolerance for the length of visual and noise exposure to urban wind turbines remains unanswered. Figure 6.2 , draws on the analogy of exposing building services in architecture to demonstrate what is vital but hidden in the same way as we might visualize our own human body as a set of exposed pipework and systems. To what extent do we want to be challenged in this way or do we refer to acknowledge but not see?
While exposing the building services as a ‘high-tech’ style was hailed by the architecture community, there is no evidence that this style gained any universal acceptance. Building services with their rotating fans for mechanical ventilation remained hidden. In fact, in some cases vistual effect very important. such as the main university student services’ Fig. 6.2 Centre Pompidou with its exposed building services (left), King’s Gate, Fig. 6.2, building in Newcastle University, planning permission was only granted when architects agreed to house the ugly building services on the underground floor to avoid visual pollution to the councillors and staff offices in the city council building was located directly opposite.
Why would urban wind turbines be dealt with differently? There needs to be social studies at this micro level and whether housing wind turbines as an unseen element and part of the building configuration paves the way to public acceptance.
It can be argued that about a decade after Bahrain’s World Trade Centre Three exposed wind turbines, the latest form of building-integrated wind turbines in the Skidmore, Owings & Merrill’s (SOM) Pearl River Tower, opted for vertical-axis turbines to minimize noise and vibration but still located them in unoccupied ‘technical floors’ to isolate them from occupants in the building. Whether this will be the trend remains to be seen.
Building-integrated wind turbines are expected to take advantage of the building height as a mast towards less turbulent flows at lower urban levels. Although the building-integrated wind turbines may yield more power than the building-mounted wind turbines, the cost per kilowatt tends to be relatively high. Compared to medium-/large-scale wind turbines, the integrated and mounted wind turbines have to invest in required foundations, tower, and cabling. According to the WINEUR (2005), for building-mounted wind turbines to be successful in generating electricity, the average wind speed should not be less than 5.5 m/s. According to Bahaj et al. (2007), Muller et al. (2009) and (Abohela et al. 2013) high-rise buildings have the largest potential for wind turbine integration when compared to low-rise structures. In locating the building wind turbine, the building roof should be approximately 50 % higher than its surroundings, and the turbine located near the centre of the roof on the most common wind direction for the location, with the lowest position of the rotor at least 30 % of the building height above the roof level.
The Warwick Wind Trials Project states that the poor sites for mounting wind turbines are single-storey buildings while good sites are 45 m-tall exposed flats in isolated settings on hilltops (Encraft 2009). Wind flow within the built environment depends on the exact geometry of all buildings on site. Integrating and positioning wind turbines on roofs need to consider roof construction materials. Turbulent flow creates stresses on the drive gear in a turbine, creating vibrations. These vibrations can, in turn, create harmonic resonances within a building structure. Metal roof decks made from thin roll-formed steel sheet, common in commercial buildings, can act like drumheads and amplify these resonances. Buildings then become musical instruments. AeroVironment, the building-integrated wind energy company, suggests in its sales literature that their turbines are only appropriate for buildings constructed of concrete. http://www.avinc.com/engineering/architecturalwind1 accessed 10/5/2016.
Abohela et al. 2011 (reviewed a number of wind integrated projects and contrasted published data on their performance. Figure 6.4 demonstrates two case studies highlighting the limitations of this integration method.
Anderson et al. (2008) studied the Green Building in Temple Bar, Dublin, as an earlier attempt for mounting three small horizontal-axis wind turbines combined with solar hot water and photovoltaic collectors (Fig. 6.3). The application resulted in excessive noise, vibration, and eventual cracking of the turbine blades. The wind turbines were determined to be uneconomical and were eventually replaced by photovoltaic cells. Another example is the Kirklees council building (civic centre 3) in the town centre of Huddersfield, UK that was retrofitted to house a large array (143 m2) of solar photovoltaic panels and two 6 kW wind turbines to generate electricity and a set of solar energy collectors (48 m2) to heat the building’s water (Fig. 6.3). Kirklees council spent ?15,000 on preparing the roof to take the structural
Fig. 6.3 (Left) The Green Building in Temple Bar, Dublin. (Right) The Kirklees council building (civic centre 3) in the town centre of Huddersfield, UK
Fig. 6.4 From left Integrated wind turbine in Pearl River Tower (courtesy SOM), Pearl River Tower in China (courtesy SOM), Strata SE1 project in London
load, vibration and improve the insulation of the roof. The Council wanted to demonstrate leadership through targeting a reduction in its building’s carbon footprint by around 8 % (15 tonnes of Carbon dioxide/annum) and reduce dependency on grid-generated electricity.
It is interesting to note that the average electricity generated from the photovoltaic array and the wind turbine was 5 % of the total electricity demand. However, similar to the Green Building in Temple Bar, the wind turbines failed to generate a reliable electricity supply and were eventually disconnected from the grid and left to promote a demonstration of good intentions. Wind-mounted turbines in both cases were seen as an Urban Wind Turbines Integration in the Built Form and Environment. It left the public with a perception that this is an expensive add on (Kirklees Environment Unit 2006).
The Warwick Wind Trials Project in the UK measured turbine performance of 26 building-mounted wind turbines from October 2007 through October 2008 and found an average capacity factor of 0.85 %. All were very small (‘microwind’, defined as less than 2 kW) turbines, including the Ampair 600 (600 W), Zephyr Air Dolphin (1000 W), Eclectic D400 StealthGen (400 W), and Windsave WS1000 (1000 W). For each installation, measured electricity production was compared with predicted production based on the manufacturers’ supplied power curves and both predicted and measured wind speeds. The study found that predicted performance exceeded actual performance by a factor of 15-17. With the worst-performing systems, the electricity required to run the electronics exceeded the electricity production, so the wind turbines were net consumers of electricity!
Building augmented wind turbines, is a form of integration when the building is sculpted based on aerodynamic principles to harness wind to be driven towards a turbine. In this case, the building form acts as the structural support for wind turbines. For example, Fig. 6.4 includes Pearl River Tower in China and the Strata SE1 building in London. However, Muller et al. (2009) noted that unless the inclusion of this technology in the building is perceived as adding value, it can’t be assumed that such projects will become the norm as urban wind turbines may not always be visually accepted.
The Strata was then voted ‘Britain’s ugliest new building’ by readers of Building Design magazine (and thus the holder of the 2010 Carbuncle Cup), Local press expressed the dismay of having to endure the ugliness of the building in addition to its rarely rotating three wind turbines. A symbol that hanged over the London horizon to remind Londoners of the failing technology performance.
It seems that the posh folks living in the upper floor penthouses objected to the noise and vibration of the spinning blades, prompting project director Ian Bogle to suggest that they should be turned off between 11 p.m. and 7 a.m. each night (Londonist, March 2010).
Although local press blamed it on the vibration, Tom Hawkins commented (http: // w w w. urban7 5. org/blog/)
It’s not so much the noise or vibration that has shut the turbines off, more like the ?54,000 + vat a year maintenance costs for generating hardly anything that is the real factor.
I know, I was involved in the second year budget for that building.
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