Thermal simulation studies of a low energy university building in Australia

A key criterion by which any building will be judged when its environmental impact is assessed is its thermal performance. This paper describes the simulation of an office module in a three-storey university building in south eastern Australia. The module, located at the north-west corner of the top floor of the building, was chosen because it is likely to have the highest cooling load - a primary concern of energy conscious designers of commercial buildings for most parts of Australia.

In the paper, the initial key assumptions are stated, together with a description of a "reference" or base case, against which improvements in thermal performance were measured. The simulation process identified the major influences on thermal performance. This enabled changes in materials and construction, as well as basic design concepts to be evaluated. Features incorporated into the base case such as a metal roof and glazed walkway were found to have adverse influence on energy consumption, and were consequently rejected in preference for an improved design which included a hypocaust slab system on the roof of the office module. The final design was predicted to reduce the annual energy consumption for heating and cooling by 72% and 76% respectively.

La performance thermique est l'un des critegraveres cleacutes de l'eacutevaluation environnementale de tout bacirctiment. Cet article deacutecrit la simulation d'un module de bureau appartenant agrave un immeuble de trois eacutetages d'une universiteacute du sud-est de l'Australie. Ce module, situeacute agrave l'angle nord-ouest de l'eacutetage supeacuterieur du bacirctiment a eacuteteacute choisi car c'eacutetait lui qui, vraisemblablement, avait la charge de refroidissement la plus eacuteleveacutee, ce qui est une preacuteoccupation majeure des concepteurs conscients des problegravemes d'eacutenergie des bacirctiments commerciaux dans la plus grande partie du pays. Le processus de simulation a fait apparaicirctre trois influences principales sur la performance thermique par rapport agrave un cas de base. Cela a permis d'eacutevaluer les modifications apporteacutees aux mateacuteriaux et agrave la construction ainsi qu'aux avant-projets. Les caracteacuteristiques inteacutegreacutees dans le cas de base comme le toit meacutetallique et la passerelle vitreacutee avaient une influence neacutefaste sur la consommation d'eacutenergie et ont donc eacuteteacute rejeteacutees au beacuteneacutefice d'un concept ameacutelioreacute qui comprenait une dalle de type hypocauste sur le toit du module de bureau. Le concept final devrait reacuteduire la consommation annuelle d'eacutenergie pour le chauffage et le refroidissement de 72 % et 76 % respectivement, ce qui donne une ideacutee de la valeur ajouteacutee au processus de production agrave partir de proceacutedures avanceacutees de modeacutelisation et de simulation.

Validated model and study of a rammed earth wall building

A 2100 m² (GFA) two-storey rammed earth building was built on the Thurgoona campus of Charles Sturt University in 1999. The building is novel both in the use of materials and equipment for heating and cooling. The climate at Wodonga can be characterised as hot and dry, so the challenge of providing comfortable working conditions with minimal energy consumption is considerable. This paper describes a thermal model of one of the second-storey offices on the west-end of the building. The simulation software, TRNSYS, has been used to predict office temperatures and comparisons are made between these and measurements made over a typical week in summer. Reasonable agreement has been achieved under most conditions. The model has been used to investigate key building parameters and strategies, including night flushing, to improve the thermal comfort in the office.

Carbon dioxide levels and ventilation strategies in 'green' office buildings

Energy efficient office buildings are intended to provide a comfortable and healthy environment for their occupants as well as reducing the energy consumption of the building. They are often designed as "showcase" buildings illustrating the potential for savings through some innovative design technology. But do such buildings actually deliver the desired energy savings and satisfactory comfort conditions for occupants? Measurements of a "green" University campus building in Victoria, Australia, designed with an innovative fabric energy storage system, demonstrate that the ventilation system is not providing acceptable indoor air quality conditions. The design strategies used to reduce energy consumption have had negative consequences on the air quality of the building. Insufficient fresh air is being drawn into the building leading to an excessive build up of carbon dioxide. It is recommended that monitoring systems need to use a wider range of measurements than temperature alone to guarantee good quality indoor air and working conditions and that commissioning of buildings should include adequate monitoring of the operational performance of the building. Designers need to be made aware of the potential consequences of their decisions when attempting innovative energy-efficient designs.

Study of heat flow through a rammed earth wall building

In 1999, a 2100 m2 (GFA) two-storey rammed earth building was built on the Thurgoona campus of Charles Sturt University. The climate at Thurgoona is considered Mediterranean – hot dry summers and cool winters. The internal and external walls of the building are constructed from 300-mm thick rammed earth (pise) and are load bearing. The thermal performance of the building has been investigated, both experimentally and theoretically over the summer and winter seasons of 2000/1. As part of these investigations heat flux sensors and thermistors were embedded in one of the external walls of a ground floor office, and data from the transducers has been used to determine the heat flow at the internal and external wall surfaces. The simulation software, TRNSYS, has been used to model the thermal performance of the same office. The programme allows the user to calculate the heat flow at the walls, which define any particular thermal zone. A comparison of measured and predicted values of heat flows and air temperatures has been used to validate the model. The model has then been used to simulate the effect of shading and added insulation on the thermal performance of the external walls in both summer and winter and these results are also presented in this paper.

Building energy efficiency labeling programme in Singapore

The use of electricity in buildings constitutes around 16% of Singapore's energy demand. In view of the fact that Singapore is an urban city with no rural base, which depends heavily on air-conditioning to cool its buildings all year round, the survival as a nation depends on its ability to excel economically. To incorporate energy efficiency measures is one of the key missions to ensure that the economy is sustainable. The recently launched building energy efficiency labelling programme is such an initiative. Buildings whose energy performance are among the nation's top 25% and maintain a healthy and productive indoor environment as well as uphold a minimum performance for different systems can qualify to attain the Energy Smart Office Label. Detailed methodologies of the labelling process as well as the performance standards are elaborated. The main strengths of this system namely a rigorous benchmarking database and an independent audit conducted by a private accredited Energy Service Company (ESCO) are highlighted. A few buildings were awarded the Energy Smart Office Label during the launching of the programme conducted in December 2005. The labeling of other types of buildings like hotels, schools, hospitals, etc. is ongoing.

Office buildings and the environment : the increasing role of facility managers

The Australian commercial stock emits 12% of all greenhouse gas emissions however the commercial property market has some inherent barriers to sustainability (DSE, 2005). A substantial proportion of the stock is owned by institutional investors who are unconvinced by the need to improve their stock and pass on running costs to tenants (Callender & Key, 1997). The links between the built environment and sustainability issues such as fossil fuel consumption and climate change is clear. In developed countries buildings contribute around half of all carbon dioxide emissions and offer considerable scope for a significant contribution to sustainability through ecologically aware design and increased energy efficiency (BRE, 1996). As capital values are not greatly affected by sustainability, owners react by doing little or nothing and the effect is to limit sustainability-related investment and undermine efforts to deliver sustainability in the sector. Facility managers are in an influential position to help address sustainability issues via an increased awareness of energy efficiency and CO2 emissions.

Even though the efficiency of buildings is primarily focused on new stock, with an existing churn replacement rate of approximately 2-3% the existing stock must be improved if urban built environment greenhouse gas emissions are to be reduced – clearly the management of existing stock must therefore contribute to substantial savings in energy use. Much of the property and surveying research has previously adopted an illustrative case study approach advocating the benefits of ESD and energy efficiency in existing buildings. This research adopts a radically different approach and profiles the entire office stock of a global CBD, namely Melbourne, which is seeking to become a carbon neutral city by 2020 (City of Melbourne, 2003). The research also employs scenario forecasting to model future changes to the stock over a fifteen year period. This paper sets out the rationale for the research and establishes the methodological approach adopted by the research team. The results provides a unique insight into the variations between different building types and grades of office buildings, which in turn will allow facility managers to gain a better understanding of where gains in energy efficiency can be made.

The role of the surveying profession in reducing carbon emissions of existing office stock in the Melbourne CBD

As professionals, surveyors and property professionals are in the front line and have a moral and ethical duty to take a lead when advising clients appropriately on measures to reduce greenhouse gas emissions from their buildings. As such, surveying professionals and the profession must increase their knowledge base and enhance their skills in respect of built environment sustainability. This research conducted a detailed analysis of energy efficiency in the Melbourne CBD office stock and examined all office buildings to identify what was likely to happen between 2005 and 2020 in respect of carbon emissions. The research profiled a business-as-usual or no change approach, a minor change approach, an intermediate approach, and a major change approach. The study examined variables such as building size, number of employees, occupancy levels, visual appearance and age. After modelling all CBD office buildings, it was recommended that an intermediate change scenario should be adopted. This course of action incorporates a transition period and includes increasing ‘green power’, increasing the number of employees per buildings, as well as reducing electricity and gas consumption. It was concluded that the surveying profession should adopt a proactive stance towards office buildings and climate change, which is currently being stifled by barriers such as a lack of education and perception concerning the long-term benefits of energy efficient office buildings. To date there has been much debate and promotion of policies to encourage the uptake of sustainability practices within the property sector; however, this research concludes that action is needed if targets are to be met.

Study of the Geelong Local Learning and Employment Network

In common with many Western nations, Australian governments, both state and federal, have increasingly embraced network-based approaches in responding to the effects of globalisation. Since 2001, thirty one Local Learning and Employment Networks (LLEN) have been established across all areas of Victoria, Australia in line with recommendations of a Ministerial Review into Post Compulsory Education and Training Pathways. That review reported that, in the globalised context, youth in transition from schooling to independence faced persistent and severe difficulties unknown to previous generations; it also found problems were frequently concentrated in particular groups and regions. LLEN bring together the expertise and experience of local education providers, industry, community organisations, individuals and government organisations. As a result of their local decisions, collaboration and community building efforts it is intended that opportunities for young people will be enhanced. My research was conducted within an Australian Research Council Linkage Project awarded to Deakin University Faculty of Education in partnership with the Smart Geelong Region LLEN (SGR LLEN). The Linkage Project included two separate research components one of which forms my thesis: a case study of SGR LLEN. My data was generated through participant observation in SGR LLEN throughout 2004 and 2005 and through interviews, reflective writing and archival review. In undertaking my analysis and presenting my thesis I have chosen to weave a series of panels whose orientation is poststructural. This approach was based in my acceptance that all knowledge is partial and fragmentary and, accordingly, researchers need to find ways that highlight the intersections in and indeterminacy of their empirical data. The LLEN is -by its nature as a network -more than the contractual entity that gains funding from government, acts as the administrative core and occupies the LLEN office. As such I have woven firstly the formation and operational structure of the bounded entity that is SGR LLEN before weaving a series of six images that portray the unbounded LLEN as an instance-in-action. The thesis draws its theoretical inspiration from the work of Deleuze and Guattari (1987). Despite increased use of notions of networks, local decision-making and community building by governments there had been little empirical research that explored stakeholder understandings of networks and their role in community building as well as a lack of theorisation of how networks actually ‘work.’ My research addresses this lack and suggests an instituted network can function as a learning community capable of fostering systemic change in the post compulsory education training and employment sector and thereby contributing to better opportunities for young people. However the full potential of the policy is undermined by the reluctance of governments to follow through on the implications of their policies and, in particular, to confront the limiting effects of performativity at all levels.

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

Evaluation of thermal and visual comfort in offices considering realistic input data and user behaviour in building simulation

Thermal and visual comfort play a very important role regarding the satisfaction of occupants with their working environments. The most effective method to achieve thermal comfort in offices is to reduce cooling loads in order to avoid additional energy-consuming devices for cooling. Building simulation software can be a helpful tool for optimisation, and typically standard values for the influencing parameters are used in order to ensure compliance to norms and regulations.

In practice many of those parameters turn out to be different compared to the simulation assumptions and the reasons may be the chosen room or building related properties as well as the user behaviour influenced by the task and the corporate culture of the company.

This paper investigates exemplary for the climate of Hamburg, Germany and a naturally ventilated typical office room, the optimisation potential of the building- and user-related parameters for thermal comfort, daylighting and view when using realistic input data for building simulation. The study has been conducted with the EnergyPlus based simulation software “Primero-Komfort” [1].

On the influence of building design, occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices. A study based on the EN 15251 adaptive thermal comfort model in Athens, Greece

According to the Intergovernmental Panel on Climate Change the buildings sector has the largest mitigation potential for CO2 emissions. Especially in office buildings, where internal heat loads and a relatively high occupant density occur at the same time with solar heat gains, overheating has become a common problem. In Europe the adaptive thermal comfort model according to EN 15251 provides a method to evaluate thermal comfort in naturally ventilated buildings. However, especially in the context of the climate change and the occurrence of heat waves within the last decade, the question arises, how thermal comfort can be maintained without additional cooling, especially in warm climates. In this paper a parametric study for a typical cellular naturally ventilated office room has been conducted, using the building simulation software EnergyPlus. It is based on the Mediterranean climate of Athens, Greece. Adaptive thermal comfort is evaluated according to EN 15251. Variations refer to different building design priorities, and they consider the variability of occupant behaviour and internal heat loads by using an ideal and worst case scenario. The influence of heat waves is considered by comparing measured temperatures for an average and an exceptionally hot year within the last decade. Since the use of building controls for shading affects thermal as well as visual comfort, daylighting and view are evaluated as well. Conclusions are drawn regarding the influence and interaction of building design, occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices, and related optimisation potential.

Using the psychrometric chart in building measurements

This paper centres around the presentation of multiple measured results on a psychrometric chart. The psychrometric chart was programmed in Microsoft Office Excel to accommodate measured results. It was written because existing programs appear not to cater for the researcher wishing to enter results electronically onto the chart. Furthermore, many existing charts are complex and cluttered displaying up to ten attributes, being intended for engineering design, whereas presenting the behaviour of living and working environments is focused on wet and dry bulb temperature and relative humidity. As well as results, users would also like to specify and adjust the ‘comfort zone’ (a shaded area on the chart) for different ‘adaptive’ or ‘seasonal’ conditions. The comfort zone is bounded by lines of constant heat loss from the skin, relative humidity and wet-bulb temperature. The paper presents various applications of the psychrometric chart for the analysis and reporting of research and discusses the programming of Microsoft Office Excel to generate the chart and display user data.

The business case for sustainable office buildings

The market for sustainable buildings has rapidly gained momentum in the design and construction phases, however it appears that development and investment in these buildings by the private sector is limited. This is further complicated by the limited information available confirming the financial viability of sustainable buildings, with relatively little research conducted into the relationship between sustainability and the market value of commercial buildings. Currently the demand for sustainable buildings in Australia and New Zealand is being encouraged through government legislation and policy, where investment by the private sector has been relatively slow to develop due to the lack of evidential proof of the economic viability of sustainable buildings. Clearly if the progress and uptake of sustainable buildings is to develop within the property market, it is essential that the relationship between market value and sustainability should be understood in order to fully inform the investment industry.

The relationship between building adaptation and property attributes

Using a database of building adaptation and property attributes this research examined every adaptation event in Melbourne's CBD between 1998 and 2008. The importance of property attributes was derived using a principal component analysis and a weighted index of optimal decision making attributes was proposed; the Preliminary Assessment Adaptation Model (PAAM). The findings indicate the relationship between property attributes is more complex than hitherto held. Overall physical attributes were found to be more important than others such as economic, environmental, legal and social attributes; however physical attributes alone are not important and are closely related to other attributes.

A passion for white elephants : some lessons from Australia’s experience of nation building

A ‘white elephant’ is a magnificent, high-status possession that is not particularly productive, costs a lot to maintain, and which you cannot get rid of. Since colonial times, Australians have had a weakness for white elephants. Traditionally, these were massive, debt-funded public works schemes that were economically, environmentally or socially dubious. In recent years, our white elephants have taken on different guises, but the ruinous expense and misdirected effort remain the same. This paper explores some of the reasons for our society’s historic enthusiasm for white elephants, and suggests some remedies.