The CH2 Building (Melbourne, Australia)

8/13/2019 The CH2 Building (Melbourne, Australia)

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Melbourne, Australia

Analysis ReportBy Blessing Mukome[N0113440P]Second Year, 2012-2013, Semester 1

Environmental Design I[AAR 2104]Lecturer: Mr Nyamande

NAT. UNIVERSITY OF SCI. & TEC

FACULTY OF THE BUILT ENV.

DEPT. OF ARCHITECTURE

The CH2


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Council House 2 (CH2) Building, Melbourne

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1.BackgroundCouncil House 2, Melbourne, Australia

In 2004, the City of Melbourne was facedwith an accommodation dilemma. Staffwas housed in dated office buildingswhich, although centrally located to theTown Hall, were nearing the end of theirlifespan.

Rather than to relocate staff toalternative offices, Council embarked ona plan to construct a new office building,Council House 2 (CH2), that would meetits spatial requirements and lead the wayin the development of an holistic green

environment.

CH2 has been designed to not onlyconserve energy and water, but improvethe wellbeing of its occupants through thequality of the internal environment of thebuilding. CH2 demonstrates a newapproach to workplace design, creating amodel for others to learn from andfollow.

The 10 storey building was designed byDesignInc in conjunction with the City ofMelbourne, and is located at 240 LittleCollins Street, Melbourne 3000, south-eastern Australia. Australia is in thesouthern hemisphere and experienceshot summers and mild winters.

2.The ArchitectMick Pearce

Mick Pearce is a Zimbabwean architectwho designs low maintenance buildingswith low capital and running costs, usingrenewable energy systems ofenvironmental control.

City of Melbourne, Aus

The CH2 Bui

Location of CH2 building here

Sun path

Wind

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3.How the design responds to theenvironment

Energy efficiency in CH2 is achieved through an integrated set of features focusing on heating,

cooling and water reuse.

3.1 Design based on ecology and climate

CH2 was designed to reflect the earths ecosystem, which involved an understanding ofMelbournes climate and weather patterns. The design of the building is such that itresponds to its environment, and to adapt and take advantage of changing weatherconditions.The building takes advantage of the Melbournes four seasons in one dayweatherconditions through making use of concepts such as cold energy storage. The building

therefore responds well in winter and summer, as well as day mode and night mode.

CH2 Building functionality during the day


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3.2 Natural light

CH2 targets and maximises the penetration ofnatural light within the building, reducing therequirement for artificial lighting.The buildings north and south facades are

comprised of alternate vertical bands of glassand thick concrete walls containing supply-airducts (on the south side) and exhaust-airshafts (on the north side). The shafts widentowards the upper levels in order to facilitateair supply and exhaust. On the other hand,the windows are at their widest at street level,narrowing at the upper levels. This enablesmore light to be admitted to the lower levels of

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CH2 Building functionality at night


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the building, where light access is restricted by surrounding buildings and there is less airdemand at the end on the air ducts.CH2 takes advantage of natural light by: Locating windows at the highest

point of the curved concrete ceilings Having an external light shelf on

the northern windows that, whileprotecting the Windows from thedirect rays of the sun, also bouncesnatural light into the building

Having moveable timber shuttersthat remain open to catch themorning sun, closing when the sunis in the western sky in theafternoon

Careful positioning and use of blindsto the northern windows. These

windows are divided into upper andlower sections, each with its ownblind. The upper blinds are onlyneeded when the sun is low in thesky in winter. The lower blind is apartial blind (900mm high), toprotect from the direct rays of thesun, while still letting in naturallight.

3.3 Cooling systemTo counter the heat load (frompeople, lighting, computers andother equipment) as well as heatgain or loss at windows orthrough the fabric of the building,conventional air-conditionedbuildings re-chill re-circulated air.The heat load is stored duringthe day and removed at night,

through two ways: Through the use of the

thermal mass of the exposedconcrete ceilings. Theconcrete absorbs the heatfrom the rising air which islater removed from theceiling at night with a 'nightpurge'.

CH2 Building showing shading devices

CH2 Building showing cooling mechanism


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By using the chilled ceilingpanels to circulate chilledwater. The chilled waterabsorbs the heat andtransports it to tanks in thebasement, that store any

heat collected during theday, which is then removedat night through evaporativecooling by cooling towerson the roof.

3.3.1 Radiant cooling

CH2s comfortable temperature is achieved primarily by radiant cooling, rather than bycooling the spaces with chilled ventilation air.

3.3.2 Thermal mass and the night purge

At night, when the external temperature has fallen below that of the internal concreteceilings, windows beneath the low points of the vaulted ceiling automatically open. Coolnight air flows in and across the ceilings underbelly, removing the previous day s heat bycross ventilation and by being drawn up through the exhaust air shafts.Exhaust air in the flues is propelled upwards by the chimney or stackeffect, assisted by the roof-mounted wind-driven turbines (when windconditions are right). This process is known as the night purge.

3.3.3 Shower towers

Located on the building's south faade, CH2s shower towers induce airmovement and cooling. The ensuing evaporative cooling process coolsboth air and water.From a simple shower rose at the top of the tower, water falls through thethree-story tube, pulling air in from openings at the top. Both the water andthe air are then cooled by this evaporative cooling process.The cool air is fed into the ground floor lobby, shops and arcade to assistwith the cooling of these spaces.

3.4 Heating system

Additional heating is provided byhot water through an underfloorhydronic system located aroundthe perimeter windows. Whenheat is required, air is designed tobe supplied at the points whereheat loss is concentrated - thewindows.

CH2 Building chilled ceiling mechanism

Shower tower

CH2 Building showing heating mechanism


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3.5 Vaulted concrete ceilings

CH2s distinctive vaulted concrete ceilingsperform a variety of functions, which include:Providing thermal mass.Enhancing air stratification in the offices by keeping warmed air further away fromoccupantsOptimizing natural light by locating windows at the highest point of the vaultincreasing the surface area of the ceiling, thereby increasing the thermal mass of theconcrete and improving the heat absorption characteristicsProviding a void for the collection of the exhaust air, avoiding the need for an array ofsurface-mounted metal ducts.

3.6 Western timber shutters

CH2s western faade features a system of recycled timber shutters (controlled byphotovoltaic cells) that protect the building from the late afternoon sun, while also enabling

views out of the building and natural light to enter the building. The shutters are open whenthe sun is in the eastern or northern sky, closing only when the sun is in the west.

3.7 Window treatment

The window treatment is designed to provide a barrier to 'heat gain' intothe building in the summer and 'heat loss' from the building in winter,through the following features:

Double-glazingTimber window frames, which are a low conductor of heat when

compared with aluminum, reducing the 'heat bridge' effectExternal sunshade from balconies (from the floor above) and fromfabric shades above doors to each balconyChilled beams over the window cooling the air and creating aprotective curtain of falling cold air across the window when heatgain is an issueUnderfloor hydronic heating grilles, located adjacent to the window,providing a protective curtain of rising warm air when heat loss is anissue.

Additionally, CH2s window treatment incorporates features to control glare:

Use of reveals on the air supply and exhaust ducts which are located both side of thewindows on the south (supply air) and the north (exhaust air) facades.External plants on the northern faade which provide lateral protection from the sunsdirect rays and help control glare by diffusing light.Internal plants, mostly for the south-facing windows can be subject to glare reflected frombuildings across the street

Window treatment on CH2building, showing timber shutte


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CH2: Quick Facts

Council House 2 is a 10-storey office building housing approximately 540City of Melbourne staff, with ground-floor retail spaces and undergroundparking. It's located at 240 Little Collins Street, Melbourne. CH2 was

officially opened in August 2006. Gross floor area (GFA): 12,536m

CH2 generates its own energy through the following:o Micro-turbine: Co-generationo Solar PowerPhotovoltaic cellso Liftso Solar hot watero Green power - CH2 is 100 per cent green power.

By opening the purge windows for four hours a night in summer, CH2reduces its cooling requirements by 20 per cent.

CH2 office spaces have 100 per cent fresh air

Lower light levels (150 lux) supported by task lights saves 2/3 of normalenergy use and have a beneficial effect on staff.

CH2 replicates the leaf area of its original site through plantings on thenorth faade and roof terrace.

CH2 was Australias first'6 Star Green StarDesign' certified ratedcommercial office building by the Green Building Council of Australia.

Sources and external links

CH2 Building, Melbourne,www.mickpearce.com

CH2,http://www.melbourne.vic.gov.au

CH2: Australia's greenest building,http://inhabitat.com

Council House Two (CH2), Melbourne, VIC,http://www.yourbuilding.org/

Council House Two - the eco office block of the future,

http://www.abc.net.au/catalyst
http://www.mickpearce.com/http://www.melbourne.vic.gov.au/http://inhabitat.com/http://www.yourbuilding.org/http://www.abc.net.au/catalysthttp://www.abc.net.au/catalysthttp://www.yourbuilding.org/http://inhabitat.com/http://www.melbourne.vic.gov.au/http://www.mickpearce.com/

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The CH2 Building (Melbourne, Australia)