Reduction of cooling requirements through optimized urban structures and processes and design optimisation in building design (smartKB*)
Initial situation / motivation
The recently published Austrian Assessment Report Climate Change 2014 confirms that warming caused by climate change is twice as pronounced in Austria as on global average. The report also forecasts a further increase of hot days and warm nights, and the frequent occurrence of prolonged heat waves. (cf. KROMP-KOLB et al., 2014)
Given these developments, an increase in the importance of cooling energy demands to ensure optimal indoor climate conditions is expected in the coming decades. Consequently, planning strategies for the thermal controllability of buildings under the influence of rising outside temperatures will be in demand. This means that appropriate development structures must be taken as a prerequisite, and appropriate construction methods and planning strategies to minimise cooling requirements must be regarded as increasingly important quality criteria for sustainable buildings in the development of new construction and renovation projects.
Although the methods of integral or networked planning have been known among experts for many years and are constantly being discussed, analysed, and developed on a theoretical level, planning processes in Austria still tend to be carried out sequentially in practice (starting from site analysis to implementation and detailed planning), without sufficient awareness of the effects of the connections between different architectural and technical planning decisions. As a result, the interactions between various kinds of design decision-making and their significance concerning the characteristics of buildings’ cooling demands are not sufficiently considered.
In principle, integrated planning is of utmost importance; however, the design of buildings with optimised cooling demands illustrates yet another aspect. Setting the course for the planning of buildings with optimised cooling demands already happens in the very first stages - starting with local development concepts and urban planning. Retroactive optimisations are difficult to achieve and if so then only with increased efforts.
Contents and objectives
The research project smartKB* has therefore addressed measures and strategies for reducing cooling energy requirements through optimised building structures as well as process and design optimisation in building planning. The project aims to minimise cooling demands of buildings at no extra expense by implementing specific design and planning strategies.
SmartKB* project focuses on externally induced cooling demands (KB*). The reduction of internal heat loads, such as by the use of energy-efficient appliances and intelligent use of waste heat, is an extensive separate topic which was purposely omitted according to the definition of smartKB* project, and which shall be dealt with elsewhere.
Since important decisions concerning interior climate and cooling demands have to be made at the earliest stages of planning, the optimisation of planning processes is a key element of smartKB* project.
In addition to the identification of current areas requiring further research, the project’s aim was the compilation of approaches and recommendations to reduce cooling demands of buildings to three task levels: optimisation and use of appropriate development structures; design strategies and passive measures for building concepts; cooling energy demand reduction through integrated planning processes.
The results from research on and analysis of these three levels were presented in an interdisciplinary workshop with experts and practitioners from the fields of architecture, urban planning, building services, building physics, sun protection, climatology, façade greening, facility management, etc. The aim of the workshop was to evaluate the intermediate results in an interdisciplinary group. By getting experienced practitioners involved in the discussion, the practical relevance of the findings was established and retained.
Based on the research’s and the workshop’s results, the interactions between development structures and cooling energy demands of buildings were described and recommendations devised for development planning as well as building planning.
Subsequently, a systematic and clearly laid out summary of key planning measures for exterior-induced cooling demands of buildings was developed and presented together with relevant interrelationships concerning building design for climatic control, and possible interactions of cooling demands-related planning decisions with other essential planning goals of modern buildings.
Results and conclusions
Increasing global warming and the formation of heat islands in densely built-up urban areas poses new challenges to urban, open space, and building planners. These challenges can, however, be mastered by taking into account a change of general conditions and the bundling of appropriate measures at different levels of planning - from development planning to urban design as well as building planning.
This requires of all those involved in the planning process an awareness for existing problems and an understanding of possible interactions between individual planning decisions across the various task levels. The arrangement of architectural structures and the design of urban spaces have a strong influence on the cooling energy demands of buildings and on the possibilities of utilising passive measures to cool buildings. At the same time, the design of each individual building affects the microclimatic conditions in the building’s environment.
These interactions were analysed and presented systematically as part of project smartKB*. Specific recommendations covering all planning and task levels were formulated and presented to the target groups. The results are available as a checklist for communities, a detailed planning guidance, and a concise pamphlet to address a broader audience.
Both city and building design need to combine numerous and sometimes conflicting goals in order to provide for an urban environment worth living in and to ensure modern, sustainable buildings. Although a major increase in the efficiency of reducing heating demands has been observed in the buildings sector during the last few years, the cooling of buildings is currently gaining importance due to global warming, heat island effects in expanding cities, and increasing requirements concerning comfort.
In order to secure the energy-efficient development of buildings and districts in the long run despite changing conditions, it is necessary to integrate the planning goals "avoidance of heat islands" and "a building with no need for active cooling or with greatly reduced cooling demands" as an integral part in the planning process, and to establish an interdisciplinary dialogue on all levels of planning between all parties involved.
„Climate Proofing“ - proof that the microclimate is not impaired at the site of a new building - should be made compulsory by law. Building certification systems have already introduced initial changes to that effect. At the building level itself, energy optimisation of a building should be based on actual microclimatic conditions and a wide range of climate data to ensure a planning solution of high resilience.
Danube University Krems, Department for Building and Environment
Project or cooperation partners
- Center for Facility Management and Security
- Center for Light Planning and Lightlab Krems
- Center for Climate-Engineering
DI Christina Ipser
Scientific Staff, Center for Facility Management and Security
Department for Building and Environment
Danube University Krems