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Sustainable refurbishmentDept. Materials and Zoology,

Cambridge

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Background to the Project

Approach to Sustainability

Design Challenges

Introduction

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Existing west Elevation

•1960s/1970s

•Post modern Architecture

•Dept Metallurgy and Mat Science•Museum of Zoology

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Artists Impression of Existing

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old• Floor area ~ 15,000m2

•Current Uses: Lecture Theatre, University Computing Service, Materials Science Labs and teaching space, Zoology Department labs, Museum of Zoology, storage •Key materials are concrete, glass and lead •Complex form which steps out as you move up, with overhanging details •The main building connects to the two towers, the Zoology building, and there is a walkway to Chemistry. Also in close proximity to the Corn Exchange building •20th Century Society describe the engineering as “elegantly ostentatious”•Original master plan concept was to link the podium to the grand arcade•Pre-dates lots of our current building regulations relating to thermal performance and structural stability

Background

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old• Museum of Zoology and Archive, Department of Zoology, Lecture

Theatre

•, CCI (Cambridge Conservation Initiative ) Urban Ecologists eg RSPB

• Offices & shared facilities

•Underpin transformation in work practices

•Sustainability Key to influencing users and planners

Key aspects of Brief

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Sustainability

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oldBenefits of refurbishment

Refurbish vs. demolition

� Reduce running and maintenance costs

� Increases thermal comfort, productivity and happiness

� Avoids the cost, noise, disruption and environmental impact of demolition

� Retains the embodied carbon in the existing structure

� Avoids new land take

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old� It is important to consider the whole life cycle

CO2 when renovating existing buildings

� We have estimated the embodied carbon in new build to be at least 3.5 times higher than the operational energy consumption in the existing Arup Building.

� The difference in operational CO2 savings between refurbishment & new-build does not justify this decision.

Embodied carbon

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Average CO2 emissions of non-domestic buildings in UK

Baseline performance data

� Gas consumption = 2,780 MWh/yr

� Electricity use = 2,012 MWh/yr

� Excluding servers

� Energy audit at Stage D

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Gas consumption

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100,000

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To

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Total gas consumption area weighted for the Arup Building & DoZ building

Departmentof ZoologyBuilding

ArupBuilding

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Electricity consumption

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0

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To

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Total electricity consumption for the Arup Building

UCS serverroom

HPC serverroom

Rest of ArupBuilding

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oldChallengesAspirations

What sustainability means for the Arup Building

• A pioneering refurbishment which expresses the sustainability credentials of the users

• A shared vision from the client, design team & building users

• Get the maximum efficiency out of the existing building

• Obtain full buy-in from the building users to ensure that long term savings are achieved

• Working within a typical university budget

• Being ‘green’, but not necessarily the ‘greenest’ in every aspect

• Finding the right balance between capital cost and operational savings

• Retaining stakeholder engagement and aspirations over the long-term

• Resolving potential conflicts in aspiration from a mixture mix of building users

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How to engage users – ask them?

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Stakeholder engagement workshop

• Stakeholder workshop with representatives from 15 organisations

• Aim was to engage with building users and establish what really matters to them in terms of sustainability for the Arup Building

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Themes arising from the workshop

� A rich mixture of responses were obtained from the stakeholder workshop

� These responses were categorised into various themes

Energy & Carbon

Materials

Water

Waste

Health & Wellbeing

Heritage & culture

Collaboration & Inclusion

Transport & Mobility

Education & Outreach

Pollution

Biodiversity & Ecology

Key

All Groups

40

24

11

12

21

9

30

12

22

2

14

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Relationships with BREEAM

� Pre-assessment was carried out, achieved a “very good” score

� Stakeholder workshops identified that users wanted to set targets for many social & collaborative factors, not captured in BREEAM

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Description Base target Stretch target Measurement process

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Development of target Project timing ResponsibilityStretch target constraint

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Energy

• ICT – computer types, diversity factors, server space requirements

• Ventilation strategy vs. layout

Biodiversity

• Green roofs / living walls – identifying CCI experts

Transport

• Cycle facilities• Remote working –

teleconferencing / offsite ICT requirements

Next steps – topics requiring input

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Health & Wellbeing

• Sustainable food choices• User control

Collaboration & inclusion

• Collaboration plans within CCI

• Collaboration plans within all users

Education & outreach

• Need to confirm baseline museum visitor numbers

• Concepts for visitor education

• Post occupancy evaluation – plans for monitoring & dissemination

Focus groups – some topics requiring input

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Value of Museum Architectural Heritage

Right to Light WayfindingFood choices

Collaborative workingTechnology & tools Accessibility Extending user group

Construction WasteOperational Waste

TargetsCompostingReduce generationRecyclingClosed-loop

Efficient useAlternative sources

Embodied CarbonResponsible procurementEnvironmental impact of production Loose fit – long life

In-use energy targetsMonitoring and management - controls and bills Building FabricBuilding Services IT

Local / GlobalRoofscape, Atrium Green/ Brown RoofButterfly house CCI Impact on Global Ecology

Flooding Run-offAir quality Low emission boilers

MitigationCarbon emissions Embodied carbonEnergy impactsRenewable Energy

Adaptation Green roof FloodingIncreased temperaturesResilience

Museum engagementCCI engagement University Public

Reduce travel Working practices

Mode shift Walking / cycling / car club

Bespoke plan

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Key design issues

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Enabling Natural ventilation

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Cellular Vs. Open plan

Open plan

Open plan

Cellular

Cellular

Cellular

Cellular

Cellular

Cellular

Cellular

Cellular

Openplan

Open plan

Open plan

Cellular

Cellular

Cellular

Cellular

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Thermal comfort in naturally ventilated perimeter bays

Bays with cellular office core Bays with cellular & open plan core

Heat gains from 16 people Heat gains from 12 people(25% less risk of overheating)

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Ventilation

Stagnation

Draughty

Length of office is approximately 25m – too long for effective cross ventilationMechanically assisted solution is required

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old• Risk of draughts in window bays, causing control difficulties

• Additional infrastructure would be required for the extract

• Higher demand for fresh air in winter

• No heat recovery in winter

Option 1: Natural intake with mechanical extract

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old• System utilises already existent supply & extract infrastructure

• Allows for improved control in both perimeter & core areas

• Heat recovery system will be present

• Can utilise chilled water system during peak cooling conditions

Option 2: Single sided natural ventilation with mechanical supply & extract

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old• Feasibility is unclear due to additional riser space requirements

• Additional infrastructure would be required

• Fresh air intake will require additional heating component in winter

• No heat recovery in winter

Option 3: Single sided natural ventilation with mechanical assisted chimney

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Summary

• Energy is not the main driver for being open plan

•Instead it will provide improved thermal comfort, better collaboration and less cramped working environment in the window bays

•Assisted ventilation solution can be achieved with no added infrastructure

•Baseline framework target can be achieved with mech. assisted ventilation solution

•Will be important to invest in modern ICT equipment over the next 3 years leading towards the move – standard equipment increases overheating risks

•Lighting & ventilation to be linked to occupancy sensors in cellular areas

•Spatial allowance for chilled water infrastructure & electrical resilience is also being designed to deal with future climate change.

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Constraints of Existing FacadeCondition, performance & planning

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oldImprovement of thermal performance of building envelope as compared

to current performance:

� % reduction in heat loss through building envelope

Thermal performance of the building envelope

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oldChallenge in understanding current performance

� Envelope inspection – build ups

� Performance estimation – U-value calc

Establish achievable improvement

� Benchmark against part L

� Consideration of feasible improvements

Thermal performance of the building envelope

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Envelope performance estimation tool

Outcome is a middle ground based on improvement where reasonable

� Limited by space, structure & access

� Limited by planning constraint

� Improvement beyond Part L where possible to compensate

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Target development example

Tool to calculateheat loss throughthe building fabric

70% reduction feasible based on building regulations

80% reduction possible if more insulation isspecified and hard-to-treat areas are addressed.

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Constraints of Existing Frame

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ICT Strategy

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ICT loads

Generic desktop computer

(with LCD monitor)

Thin client computer

(with LCD monitor)

Laptop

(with docking station + LCD monitor)

99 Watts 33 Watts38 Watts

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Thin client computers

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Laptop computers

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Generic desktop computers

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Lessons learned so far...

- Developed Bespoke Sustainability Framework

- Good level of User Engagement - Helps define the Problem

- Possible to Deliver Natural Ventilation to >60% of Building

- Targetting 70% reduction in Conduction Heat Losses (thermal bridges still an issue)

- LAM (Laser Assisted Modelling) survey of Existing Frame successful but watch the briefing !

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Laser Survey Model

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Central Model Development

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Existing Vertical Services Distribution – 1st Floor Plan

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Existing Horizontal Services Distribution

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Access & Maintenance

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