adaptability and change: low energy design, urban microclimate and climate change introduction air...

Adaptability and Change:Low energy design, urban microclimate and climate changeAdaptability and Change:Low energy design, urban microclimate and climate change

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

ConclusionsKoen Steemers

Cambridge Architectural Research Limited

and

The Martin Centre for Architectural and Urban Studies

Department of Architecture, University of Cambridge

Adaptability and Change:Low energy design, urban microclimate and climate change

The dilemma Buildings cause 40-50% of emissions,

creating pollution & climate change. Buildings will be affected by the urban microclimate and climate change.

1. Reduce the energy consumption and emissions of buildings e.g. through passive design.

2. The urban climate and climate change can make the energy performance of buildings worse, or environmentally unacceptable to the occupants.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Overview:• The urban environment and climate

change has begun to enter the consciousness of the construction industry.

• The worry is that the response will be negative – i.e. to increase the defensive capabilities of the building by throwing more energy use and systems at it. The result would be increased energy use, increased emissions and thus increased rate of climate change…not a sustainable sequence of events.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


The challenge:1. To show that increased energy use (e.g.

conventional air conditioning) is not the solution to adapting to the urban microclimate or climate change.

2. To demonstrate how low energy design and comfort theory can address both mitigation and adaptation.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


• Our senses have evolved to respond to a dynamic environment.

• Yet our buildings have become increasingly closely controlled, whilst consuming significantly greater amounts of energy.

fans/pumps12%

lighting47%

heating41%

Nat Ventfans/pumps

30%

refrigeration14%lighting

34%

heating22%

Air Con

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Implications of poor air con:• Reduced indoor air quality• Sick building syndrome • Increased absenteeism• Reduced productivity

Performance can be radically different from that predicted – energy figures of twice those calculated are not rare in the first year of operation. Why?

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Performance discrepancies:• hasty commissioning • lack of awareness of occupant

interaction • lack of post occupancy surveys • rare feedback to the design team

As a result, the construction industry tends to be slow to learn, change and adapt to new challenges.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


• Mechanical control is in its infancy• Passive design has centuries of tried and

tested strategies

Improved understanding of the interactions between building, environmental performance and occupant satisfaction is emerging.

- form and fabric are an integral part of the environmental strategy- reducing the reliance on mechanical systems- enabling the occupant to adapt and interact

with their own environment

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Low energy design and comfort• Examples from extreme climates• Adaptation of design and the occupants • Relevant to challenges presented by the

urban microclimate and climate change

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Hot-arid: Courtyard buildings• Spaces (and locations within spaces)

offering improved comfort conditions are consistently sought by occupants.

25

30

35

40

45

50

00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Tem

pera

ture

Chosen temperature Comfort temperature

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions

Source: Abu Merghani, The Martin Centre, University of Cambridge


A range of spatial conditions: internal rooms, intermediate verandas and external courtyards, with various thermal characteristics.

0

20

40

60

80

100

B1-1 Jan B1-2 Mar B1-3 Apr B1-4 May B1-5 June

Perc

engt

age

of ti

me

Oudoor spaces

Intermediate spaces

Indoor spaces

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions

Source: Abu Merghani, The Martin Centre, University of Cambridge


• Other adaptive opportunities: deploying openings and shading, changes to dress, activity level, posture, hot/cold drinks, sprinkling of courtyard and use of fans.

• The range and accumulation of adaptive opportunities available significantly improves comfort.

base case adapted caseair temp 30.5 28.0rad temp 30.5 28.0air speed 0.1 0.2clo 0.5 0.4met 1.2 1.1PPD 68.4% 17.5%

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions

Source: Nick Baker, The Martin Centre, University of Cambridge


The adaptive office: • Trend towards more flexible working

patterns and office layouts, exemplified by the work of Frank Duffy and DEGW.

• Though not explicitly linked to comfort seeking, the notion of for example ‘hot-desking’ offers that potential.

• Also, efficient space use means less floor space, which in turn could reduce the energy use per occupant.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Adaptive building envelope:• Perceived comfort and productivity are

associated with the opportunity to interact with the building envelope. – e.g. views, operable windows and blinds.

• Small windows v. glazed facades: – temporary spatial adjustments to avoid sun; – more thermal mass; – reduced solar gains; – less need for shading (nb daylight and views); – localised ventilation; – reduced costs, etc.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Adaptive systems:• Avoid centralised BMS which leaves the

occupants powerless. • Use sensors and controls which enable

local occupant interaction. • Use systems that respond to occupant

interaction with the building (e.g. opening a window turns off heat).

• The system should serve the occupant, combining robust climatic design with intelligent controls and components, to maximise adaptability.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Comfort criteria:• Generally: 27oC <2% of occupied period.• CIBSE: 25oC <5% of occupied period. • A change from 27 to 25oC is a step back,

particularly in the light of climate change.

0

10

20

30

40

50

60

Light (27) Med (27) Heavy (27) Light (25) Med (25) Heavy (25)

Day

s of

ove

rhea

ting

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Applying the criteria:• Either criterion requires quite

sophisticated dynamic thermal modeling. • Despite such sophistication, no account

is taken of adaptive opportunities – a key determinant of comfort and energy use.

• Detailed simulation is only as good as the input data and assumptions, and reveals little about the robustness of a design.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Conclusions:• Adaptation, through building design and

occupant interaction (spatial, personal and systems control).

• Current criteria are insufficient to determine occupant comfort, complex to apply, and likely to result in the increased energy demand.

• EU standards should be designed so as not to limit diversity and regionalism.

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions


Conclusions: Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions

School, Como, Italy (Terragni) Library, Viipuri, Finland (Aalto)Source: Peter Fisher, The Martin Centre, University of Cambridge


The End

Introduction

Air conditioning

Adaptive comfort

Adaptive design

Comfort criteria

Conclusions

adaptability and change: low energy design, urban microclimate and climate change introduction air...

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