Adaptability and Change: Low energy design, urban microclimate and climate change Introduction Air conditioning Adaptive comfort Adaptive design Comfort criteria Conclusions Koen Steemers Cambridge Architectural Research Limited and The Martin Centre for Architectural and Urban Studies Department of Architecture, University of Cambridge

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. Introduction Air conditioning Adaptive comfort Adaptive design Comfort criteria Conclusions Air Con Nat Vent

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. 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. 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. 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. 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 The End