Balancing comfort expectations and greenhouse gas emissions, thermal comfort in office buildings in a changing climate

According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the construction sector has the greatest potential for climate change mitigation. This work investigates the potential for climate change mitigation in naturally ventilated and mixed mode office buildings, by evaluating the range of influence of building design and occupants on greenhouse gas emissions as well as thermal and visual comfort.

Thermal comfort is evaluated according to the EN 15251 adaptive thermal comfort model, visual comfort is based on daylight autonomy and view. Parametric studies have been conducted based on building simulation for the climate of Athens, Greece. Input data are based on a literature review, and on results from a field study conducted among office occupants and architects in Athens.

The results show that the influence of occupants on greenhouse gas emissions is larger than the influence of building design. Energy saving office equipment, as well as active use of building controls for shading and lighting by occupants are crucial parameters regarding the reduction of CO2 emissions. In mixed mode buildings, the coefficient of performance of the cooling system is an important parameter as well. Regarding thermal and visual comfort, the influence of building design is predominant. A green building, well protected against heat from the sun and able to balance solar and internal heat gains, provides higher comfort levels and is less affected by the influence of occupants. In mixed mode buildings, building design is the predominant influence on the magnitude of cooling loads. A hot summer including heat waves can significantly reduce thermal comfort and increase the resulting greenhouse gas emissions. Green buildings are least affected by these influences.

The EN 15251 adaptive thermal comfort model provides a thermal comfort evaluation method valid throughout Europe. However, for the Mediterranean climate of Athens, Greece, most of the configurations investigated within this study do not meet the requirements according to this model. EN 15251 refers to an adaptive thermal comfort model for naturally ventilated and to a static model for mechanically ventilated buildings. For mixed mode buildings, the static model is recommended, but literature indicates that occupants in those buildings might be more tolerant towards higher temperatures. The hypothetical application of the EN 15251 adaptive thermal comfort model in mixed mode offices, as investigated in this study, shows potential for greenhouse gas emission savings. However, this influence is small compared to that of building design and occupants. Conclusions are drawn regarding the categorisation and exceeding criteria according to EN 15251 adaptive thermal comfort model for offices in a Mediterranean climate.

The results of this work show, that not only green buildings, but also green occupants can significantly contribute to the mitigation of the climate change. Mechanisms of the real estate market as well as the lifestyle of occupants are important influences in this context. Sustainability therefore refers to finding the right balance between occupant’s comfort expectations and resulting greenhouse gas emissions for a specific building, rather than optimisation of single parameters

Balancing buildings and occupants - a holistic approach to thermal comfort and greenhouse gas emissions in mixed mode offices

This paper describes a holistic approach to comfort and greenhouse gas emissions in mixed mode offices. It is based on parametric studies for a typical cellular office in the Mediterranean climate of Athens, Greece, using building simulation.

Considered parameters are the influence of different building design, varying occupant behaviour and internal heat loads, as well as of an exceptionally hot summer. Additionally, the performance of a cooling strategy following the comfort limits according to the EN 15251 adaptive model is compared with the common fixed cooling set point 22°C.

The performance of mixed mode offices is evaluated regarding thermal comfort, daylight autonomy and related greenhouse gas emissions. Results indicate strategies to improve sustainability in mixed mode offices in Athens, by balancing the influencing parameters.

Better definitions, better buildings?

Because of the magnitude of their impact on the environment, the way we design, build and operate our buildings must change. So-called ‘sustainable’ buildings are now appearing in our cities. However, the term ‘sustainable’ is now so widely used that it has lost all meaning. Other equally ill-defined descriptions are also being used of the new generation of buildings appearing in the built environment. These terms, including ‘environmentally friendly’, ‘low energy’ and ‘green’. This paper argues that a lack of clarity over meaning can foster illusions, reflect careless thinking and/or provide cover for a business-as-usual agenda. In universities, courses for today’s architecture and construction management students are being redesigned to include ‘sustainability’. However, a review of subject guides from Schools of Architecture in Australian universities indicates that ‘sustainability’ is also being used misleadingly. While there is merit in both of the professional accreditation systems for buildings in Australia, there is certainly room for improvement. One scheme reinforces illusions by rewarding features that should merely be regarded as good building design. The ‘sustainability’ objectives of the other scheme have narrowed significantly from the original intent. The authors conclude that the critical thinking of our students will be sharpened by defining sustainability correctly and that meaningless descriptors of buildings must be challenged.

Garden & landscape heritage:a crisis of tangible & intangible comprehension and curatorship

The cultural landscape of George Town, Penang, Malaysia, embraces the historic enclave of George Town as well as a range of other significant colonial vestiges adjacent to the entrépôt. Many of these landscapes cannot be isolated from the énclave as they are integral to and part of its cultural mosaic and character. Perhaps the most important are the Penang Hill hill-station landscape and the 'Waterfall‘ Botanic Gardens. The latter is an under-valued 'garden of the empire‘—a garden that significantly underpinned the development and historical and botanical stature of the Singapore Botanic Gardens.This paper reviews the cultural significance of colonial botanic gardens as they were established around the world during the scientific explosion of the late 1800s. It addresses their position within World Heritage listings, and considers the role, significance and importance of the 'Waterfall‘ Botanic Gardens within this context, within the concept of 'cultural landscapes‘, and critiques its absence from the recent World Heritage Listing of the colonial enclaves of Georgetown and Meleka in Malaysia.

Validating planning heritage : evidence and reasoning for national heritage recognition of the 'City of Adelaide Plan' and park lands

The Adelaide Park Lands and the ‘City of Adelaide Plan’ (1837), as prepared by Colonel William Light, have long been held up as an international precedent in town planning literature. The celebrated model, embraced by Ebenezer Howard to describe his Garden City theory, has several layers of cultural landscape heritage. The ‘Plan’, in recent years, has been subject to a rigorous investigation of its Indigenous and colonization evolutionary layers to inform moves to list the landscape as possessing national heritage status under relevant Australian heritage regimes, and more recently under the National Heritage List regime, as a pre-emptive strategy towards an eventual World Heritage nomination of the cultural landscape and ‘Plan’.

Cross-Territorial heritage sites : towards a cross-cultural heritage practice

This paper will describe a current research project at Deakin University’s Cultural Heritage Centre for Asia and the Pacific which aims to develop our current understanding of heritage beyond the national frame usually given to it. The project focuses on a number of heritage sites associated with Australia’s war time heritage. However, all of these sites are located on foreign soil, in land which is not owned by the Australian government. Moreover, because of their location, these sites may or may not have significance for the countries where they are located or to other participants in the same war. Their location in another country and in other people’s narratives poses a complex problem for those who want to conserve, manage and interpret these sites in a manner which preserves their significance to Australia. Is it possible to do this while also recognising other people’s investment or lack of, in these sites? What do we need to think about when recognising the existence of dissonant heritage not only within a nation but across nations? And can this dissonance be used to encourage crosscultural dialogue? Using current understandings of heritage as potentially dissonant, and accepting the need to work within a pluralist frame which supports and argues for cultural diversity, this project explores what happens when this dissonance and diversity occurs not simply within a nation but across national borders. The paper will explore these issues by looking at the interpretation of the Thai-Burma railway, one of a handful of sites which Australians use to mark Anzac Day, the national day of remembrance for those who died fighting for their country.

Height and construction costs of residential high-rise buildings in Shanghai

A widely recognized theme of construction economics suggests that the cost of construction per square meter increases as building height rises. However, over a number of years, research conducted regarding the height and cost issue has established a classic relationship between the two factors which can be represented by a U-shaped curve. This paper describes the study of the height-cost relationship of high-rise residential buildings in Shanghai in terms of the total construction cost and elemental costs while considering the context and commonality of buildings. This research was developed as an extension of the previous work, which examined data for buildings in Hong Kong. Initial findings indicate that the curves illustrating the relationships between height and cost of residential buildings in Shanghai and Hong Kong exhibit different profiles. The dissimilarities indicate that different sets of criteria should be applied in the judgment of height that affects cost in different locations. In terms of elemental costs, the findings suggest that there are differences in the way these costs react to changes in the building height.