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EXPLOITING URBAN PHYSICS The Role of Tall Buildings in the Urban Setting CIBSE Resilient Cities Julie Futcher, Gerald Mills & Ivan Korolija [email protected] @juliefutcher 1 1
EXPLOITING URBAN PHYSICS
The Role of Tall Buildings in the Urban Setting
CIBSE Resilient Cities
Julie Futcher, Gerald Mills & Ivan Korolija
[email protected]@juliefutcher
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Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
50% of the global population live in urban environments (3.3billion people 2008) / occupy <3% of the ice free landproduce 70% of global CO2 / consume 2/3rds of global energy/ with 50% of all energy taken by buildings / increase in tallbuildings / are warmer than their surrounding area (?) / andvenerable to climate change
Cities
2
Current UK BUILDING ENERGY MANAGEMENT Measures
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
Limited to the individual building
■ 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
measures (operational)
This is what
we do
This is what we have
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The Role of Building and Urban Form as an Energy Management Parameter
4Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
Buildings in cities are not Energy Islands - They share the urban space & passive/renewable resources.
HOWEVER Responsibility for the net-energy effects of a building on the wider environment has yet to be determined
5Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
The EASTERN CLUSTER City of London
25m
The Shard
Existing
Under Construction
Proposed
300m
180m
COMMERCIALAREA
RESIDENTIALAREA
The
He
ron
Tow
er
10
0 B
isho
psgate
30
St Marys A
xe (b
ehind)
BISHOPSGATE
22
Bish
op
sgate
Lloyd
s Bu
ildin
g
Willis B
uild
ing (b
ehind)
Eastcheap20FC BOUNDARY ESTATE BISHOPSGATE GOODS YARD
25m
52
-54
Lime
St (beh
ind)
12
2 Le
ade
nh
allStree
t
River Thames
The Heron PV array will
be shielded by 100 Bishopsgate
The near noon shadow from TheShard will extend more than 350meters for half the year
The Bishopsgate Goodsyard Development and The Boundary Estate,represent contrasting methodologies to city planning two neighbouringschemes, densely compact, and passive solar design. They highlight thegrowing conflict between the right to a passive resource and those of highdensity.
Ap
pro
ach
Flo
w
The Eastern Cluster in the City of London, is a good exampleof how tall buildings can be mutually beneficial. For glassclad office buildings with high internal gains, shadingbetween surfaces is desirable. Tall buildings offeropportunities to improve urban area, for example they canbe used to pull fresh air into the city, free up land to creategreen spaces & to encourage outdoor activity, and improveour urban areas. However they should be planned withcaution, as they typically steal our access to sunshine.
The form of 20 Fenchurch Street south facing façade acts as agiant parabolic mirror, transforming the buildings façade into agiant laser that focus scorching all in its path. More recently,the façade was also found to transforms itself into a giant windcatcher, diverting the wind flow off the River Thames to thebase of its giant stature.
6Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
The Selfish Giants
DAYTIME – incoming radiation Area of entrance mat to barbers shop Eastcheap, scorched by beam
20FC demonstrates two significant but overlooked energy management parameters relating to the role of building form,1) The concave convex and cantilevered form deflects solar energy away
from the interior, making the building form more efficient in terms of cooling
2) The deflected beam has an energy implication of the surrounding setting
7Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
The
He
ron
Tow
er
(pla
nn
ed)
10
0 B
isho
psgate
Eastcheap
(pla
nn
ed)
52
-54
Lime
St
NIGHT TIME – outgoing radiation
at night, the effect of reducing the sky view is to increase longwave (terrestrial) radiation
with the surrounding warmer urban surfaces, orthe re-radiation of longwave radiation betweensurfaces. Thus, the heat remains ‘trapped’. The
net effect is to reduce the rate of night-timecooling, a critical factor in the formation of the
UHI. This is a form driven effect!
some building forms in - situ may be better than others at facilitating the dispersal of trapped heat, minimising the localised nocturnal urban heat island effect
12
2 Le
ade
nh
allSt
(pla
nn
ed)
22
Bish
op
sgate
8Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
December - noon
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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
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
10Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
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In current condition heating demand in BE during the six-month winter(September to March) is estimated at 90kWh/m2/yr
Shading increased between 1% and 5%. Greatest difference on upper floors(more exposed to solar gain) and those closest to BGY / buildings to thesouth east were less affected due to current overshadowing the Avant-gardetower
Impact if BE’s current building fabric were to be upgraded to those requiredby the current Part L (2014)
Energy performance improved up to 70% / Impact on this lower winterheating demand of up to 9% / Greater importance of solar gain due torelative impact of overshadowing is increased!
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?
Julie Futcher – [email protected] – Exploiting Urban Physics – September 16th – CIBSE Resilient Cities
FORM DRIVEN urban
climate effects
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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’
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 Isolationhttp://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 Fryscraperurban-climate.org/newsletters/IAUC049.pdf
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