EXPLOITING URBAN PHYSICS The Role of Tall Buildings in the Urban Setting CIBSE Resilient Cities Julie Futcher, Gerald Mills & Ivan Korolija [email protected] @juliefutcher 11 Cities 50% of the global population live in urban environments (3.3 billion people 2008) / occupy <3% of the ice free land rds produce 70% of global CO2 / consume 2/3 of global energy / with 50% of all energy taken by buildings / increase in tall buildings / are warmer than their surrounding area (?) / and venerable to climate change 2 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities Current UK BUILDING ENERGY MANAGEMENT Measures ■ Energy supply from both on and off site renewables (Limited Resource – often limited to the individual building) ■ Optimising the building fabric and the efficiency of energy demanding systems (regulated) ■ Change behaviour patterns towards energy efficient Limited to the individual measures (operational) building 75% of the UK 2050 building stock is already in place*/ 80% net-reductions CO2 by 2050!! / THEREFORE THESE MEASURES ALONE ARE UNLIKELY TO BE SUFFICIENT IN REACHING TARGET REDUCTIONS - SO in an attempt to address these shortfalls, our work considers an additional but often overlooked measure; Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities 3 The Role of Building and Urban Form as an Energy Management Parameter Buildings in cities are not Energy Islands - They share the urban space & passive/renewable resources. This is what we do HOWEVER Responsibility for the net-energy effects of a building on the wider environment has yet to be determined This is what we have 4 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities 4 5 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities Existing Under Construction The Selfish Giants Proposed 300m RESIDENTIAL COMMERCIAL AREA AREA The Heron PV array will 180m be shielded by 100 Bishopsgate Approach Flow Flow Approach 25m 25m 100 22 Bishopsgate 22 52 Willis Willis The 30 St Marys AxeMarys St 30 122 Lloyds Building Lloyds River Thames BOUNDARY ESTATE BISHOPSGATE GOODS YARD BISHOPSGATE The EASTERN CLUSTER - 20FC Eastcheap The Shard 54 Lime Lime 54 Bishopsgate Leadenhall City of London Tower Heron Building Building The Bishopsgate Goodsyard Development and The Boundary Estate, The Eastern Cluster in the City of London, is a good example The form of 20 Fenchurch Street south facing façade acts as a The near noon shadow from The represent contrasting methodologies to city planning two neighbouring of how tall buildings can be mutually beneficial. For glass St giant parabolic mirror, transforming the buildings façade into a Shard will extend more than 350 (behind) giant laser that focus scorching all in its path. More recently, meters for half the year schemes, densely compact, and passive solar design. They highlight the clad office buildings with high internal gains, shading (behind Street ( the façade was also found to transforms itself into a giant wind growing conflict between the right to a passive resource and those of high between surfaces is desirable. Tall buildings offer behind density. opportunities to improve urban area, for example they can catcher, diverting the wind flow off the River Thames to the base of its giant stature. be used to pull fresh air into the city, free up land to create ) green spaces & to encourage outdoor activity, and improve ) our urban areas. However they should be planned with caution, as they typically steal our access to sunshine. 6 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities DAYTIME – incoming radiation Area of 20FC demonstrates two significant but overlooked energy management entrance mat parameters relating to the role of building form, to barbers shop 1) The concave convex and cantilevered form deflects solar energy away Eastcheap, from the interior, making the building form more efficient in terms of scorched by cooling beam 2) The deflected beam has an energy implication of the surrounding setting 7 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities NIGHT TIME – outgoing radiation at night, the effect of reducing the sky view is to increase longwave some building forms in - situ may be better than (terrestrial) radiation others at facilitating the dispersal of trapped heat, with the surrounding warmer urban surfaces, or minimising the localised nocturnal urban heat the re-radiation of longwave radiation between island effect surfaces. Thus, the heat remains ‘trapped’. The net effect is to reduce the rate of night-time cooling, a critical factor in the formation of the UHI. This is a form driven effect! 22 ( planned) Bishopsgate 122 52 (planned) 100 100 Bishopsgate (planned) - The Heron Tower Heron Tower The 54 54 St Lime Leadenhall St Eastcheap 8 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities BGY & BE represent contrasting methodologies to city planning. BGY illustrates a modern approach - compact, densely occupied - energy efficient and limits carbon emissions. Meanwhile, the BE represents passive design that maximises layout to access both sun and daylight with streets oriented to align to the solar path. These two neighbouring schemes highlight the growing conflict between the right to a passive resource and those of high density December - noon 9 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities November - mid-morning, noon & mid-afternoon with (top) and without (bottom) proposed towers 10 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities In current condition heating demand in BE during the six-month winter Impact if BE’s current building fabric were to be upgraded to those required (September to March) is estimated at 90kWh/m2/yr by the current Part L (2014) Shading increased between 1% and 5%. Greatest difference on upper floors Energy performance improved up to 70% / Impact on this lower winter (more exposed to solar gain) and those closest to BGY / buildings to the heating demand of up to 9% / Greater importance of solar gain due to south east were less affected due to current overshadowing the Avant-garde relative impact of overshadowing is increased! tower This example poses some questions on how to manage energy need and carbon compliance in cities: where does accountability for the building envelope end? who should be accountable for the energy costs (or benefits) that are distributed in the neighbourhood? and; did allowable solutions offer a framework for energy management at the urban scale? 11 Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities FORM DRIVEN urban climate effects These examples demonstrate that energy management strategies require a spatial approach that accounts for the wider impacts of buildings on their surroundings We are in the early stages of developing a planning framework for ‘form’ driven microclimate effects to guide urban development in a climate sensitive manner’ 12 Related Publications Building Design (BD) September 2015 Have we learnt anything from the Walkie Scorchie? http://www.bdonline.co.uk/buildings/carbuncle-cup/have-we-learnt-anything-from-the-walkie-scorchie?/5077347.article RICS June 2015 Good Neighbours - page 12 http://www.rics.org/Global/Building_Control_Journal_June_July_2015.pdf#page=12 CIBSE – April 2015 Pushing the Envelope http://portfolio.cpl.co.uk/CIBSE/201504/opinion-futcher/ CIBSE – Feb 2015 Walking among Giants http://portfolio.cpl.co.uk/CIBSE/201502/tall-buildings/ Architects Journal (AJ) - August 2014 We Cannot Assess Skyscrapers in Isolation http://www.architectsjournal.co.uk/news/julie-futcher-we-cannot-assess-skyscrapers-in-isolation/8668340.article CIBSE – July 2014 ‘Shadowlands’ http://portfolio.cpl.co.uk/CIBSE/201407/modelling-tall-buildings/ CIBSE – Feb 2015 ‘The Selfish Giants’ http://portfolio.cpl.co.uk/CIBSE/201402/opinion-julie-futcher-gerald-mills/ IAUC – Sep 2013 ‘No Building is an Energy Island, The Cautionary Tale of the Fryscraper 13 urban-climate.org/newsletters/IAUC049.pdf.