Embodied energy analysis of the refurbishment of a small detached building

Energy efficient design principles and the minimisation of operational energy requirements have been demonstrated in the refurbishment of a small existing residential building. Significant thought has been given to these areas, together with an emphasis on the minimisation of resource consumption and material wastage. However, less consideration has been given to the embodied energy of the additional materials, components and systems required to meet these aims. The additional embodied energy may reduce the advantages of minimising the operational energy consumption by extending the energy payback period beyond the life of the building. In general, the embodied energy of buildings and their products has been found to be significant, when national average input-output data is used to fill gaps in traditional life-cycle assessment inventories. Through the use of an input-outputbased hybrid embodied energy analysis, the embodied energy of this refurbished building has increased by 63% compared to the existing building, showing the impact that filling the gaps in traditional inventories can have on energy payback periods.

Validation of the use of Australian input-output data for building embodied energy simulation

Traditional!y, the simulation of buildings has focused 011 operational energy consumption in an attempt to determine the potential for energy savings. Whilst operational energy of Australian buildings accounts for around 20% of total energy consumption nationally, embodied energy represents 20 to 50 times the annual operational energy of 1110st Australian buildings. Lower values have been shown through a number of studies that have analysed the embodied energy of buildings and their products, however these have now shown to be incomplete in system boundary. Many of these studies have used traditional embodied energy analysis methods, such as process analysis and input-output analysis, Hybrid embodied energy analysis methods have been developed, but these need to be compared and validated. This paper reports on preliminary work on this topic. The findings so far suggest that current best-practice methods are sufficiently accurate for most typical applications, but this is heavily dependant upon data quality and availability.

Assessment of embodied energy analysis methods for the Australian construction industry

Environmental assessment of buildings typically focuses on operational energy consumption in an attempt to minimise building energy consumption. Whilst the operation of Australian buildings accounts for around 20% of total energy consumption nationally, the energy embodied in these buildings represents up to 20 times their annual operational energy. Many previous studies, now shown to be incomplete in system boundary or unreliable, have provided much lower values for the embodied energy of buildings and their products. Many of these studies have used traditional embodied energy analysis methods, such as process analysis and input-output (1-0) analysis. More recently, hybrid embodied energy analysis methods have been developed, combining these two traditional methods. These hybrid methods need to be compared and validated, as these too have been considered to have several limitations. This paper aims to evaluate a recently developed hybrid method for the embodied energy analysis of the Australian construction industry, relative to traditional methods. Recent improvements to this hybrid method include the use of more recent 1-0 data and th.fl inclusion of capital energy data. These significant systemic changes mean that a previous assessment of the methods needs to be reviewed. It was found that the incompleteness associated with process analysis has increased from 49% to 87%. These findings suggest that current best-practice methods of embodied energy analysis are sufficiently accurate for most typical applications. This finding is strengthened by recent improvements to the 1-0 model.

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.

A development of environmental conscious design of prison buildings

Environmental conscious design refers to variety of approaches in architecture design that covers technical, behavioural, and functional aspects (Goulding et al, 1992). These approaches usually include contradictory measures with social indicators (Sykes, 1995; Norton, 1999). The contradiction is magnified in incarceration architecture, which is very specific type of buildings (McConville, 2000). Prison buildings represent the split between the society requirements and the needs for the users, in this case the prisoners, to have comfortable environment. Energy as an ultimate natural resource reflects both the cost to the society, in terms of cooling/ heating load and the need for comfort and rehabilitation of prisoners (Al-Hosany and Elkadi, 2000). Different energy codes tend to control the thermal behaviour of buildings in certain environment in order to maximise their energy efficiency (e.g. CIBSE, 1999). In prison buildings, some of the main variables of such code are not relevant. While energy codes, for example, regulate the use of glass in buildings by either minimise the openings size (prescriptive criteria) or by determine an overall limit of heat transfer (performance criteria), the objective in prison buildings is to minimise glass areas for security purposes. This leads in turn to reduction in visual and comfort levels in prison cells. The aim of this paper is to address the balance between the society requirements of reducing energy consumption in prison buildings and the need for humane and comfortable environment for prisoners in order to maintain sustainability. The paper investigates the possible role of façade technologies to bridge the gap between requirements of both society and prisoners.

Low energy design strategies for high-rise apartments in Hong Kong

The thesis provides comprehensive computer simulations of energy consumption in typical high-rise apartment buildings in Hong Kong with a focus on the effects of passive design strategies and air conditioning set-points. This research is related to energy efficient development and urbanisation in the tropics.

Climate change sensitivity of comfort and energy performance criteria for offices

The climate change scenarios of the Intergovernmental Panel on Climate Change (IPCC) predict a significant increase in temperatures over the next decades. Architecture and building occupants have to respond to this change, but little information is currently available in how far the predicted changes are likely to affect comfort and energy performance in buildings. This study therefore investigates the climate change sensitivity of the following parameters: adaptive thermal comfort according to Ashrae Standard 55 and EN 15251, energy consumption, heating and cooling loads, and length of heating and cooling periods. The study is based on parametric simulations of typical office room configurations in the context of Athens, Greece. They refer to different building design priorities and account for different occupant behaviour by using an ideal and worst case scenario. To evaluate the impact of the climate change, simulations are compared based on a common standard weather data set for Athens, and a generated climate change data set for the IPCC A2 scenario. The results show a significant impact of the climate change on all investigated parameters. They also indicate that in this context the optimisation of comfort and energy performance is likely to be related to finding the best possible balance between building (design) and occupant behaviour and other contextual influences, rather than a straightforward optimisation of separated single parameters.

Analysing building energy use using sub metering and external weather data

The Intergovernmental Panel on Climate Change and the McKinsey Greenhouse Gas abatement studies have highlighted reduction of building energy consumption as a primary cost-effective element in the abatement of Global Warming. Nevertheless, the energy investigation in most of our existing building stock remains at a novice level at best. Building sub-metering, by which we mean any secondary, hourly, metering (after the main) of various circuits, provides substantial information on when and where energy is used in specific buildings. Furthermore, combining this information with external weather data provides information beyond basic metering results. This paper discusses three case studies and explains how sub-metering, augmented by external solar and temperature data, benefits energy management and identified problems. It explains how different methods of analysing energy usage allowed: justifiable sizing of a solar photovoltaic system, with a calculated Cooling Degree Unit, identified the absence of savings from a proprietary chiller controller, and the energy variation due to user schedules and external conditions indicated anomalies in energy use. The advantages of wireless access are noted. Extracting information in graphical formats suggests better strategies to understand and control energy use.

A classification of healthcare facilities: toward the development of energy performance benchmarks for day surgery centers in Australia

OBJECTIVE: In the literature, there is no consistent classification of healthcare facilities. In order to benchmark, assess, and compare the environmental performance of these buildings, it is important to clearly identify the typology within the scope of a particular research. This article identifies the different typologies within the healthcare sector, particularly in Australia, with the aim of the development of energy performance benchmarks for day surgery/procedure centers. BACKGROUND: Healthcare buildings encompass a wide range of facilities. They all share the same purpose of healing and offering a health service for patients. However, they vary significantly in terms of patient type and service provided. These buildings consume a considerable amount of energy, and as a result of the different designs and sizes, their pattern of energy consumption varies. METHODS: The research used a systematic review of the literature to determine how the term "healthcare facility" has been employed in different contexts. In order to better understand the differences in healthcare facilities, definitions and the origin of hospitals and healthcare facilities are introduced and a framework for the classification of healthcare facilities and hospitals is proposed. RESULTS: Healthcare facilities are classified into the following six categories: patient type, care provided, management and ownership, level of care, facility size, and location. Based on these classifications, a categorization for the studies of energy performance in healthcare is introduced. CONCLUSIONS: This study provides a basis for assessment and comparison for a particular healthcare building typology that will assist researchers working in the field of design and energy assessment of healthcare facilities.

Investigating energy and indoor environmental performance of aquatic centres

Aquatic centres are popular recreational facilities in Australia and other developed countries. These buildings have experienced exponential demand over the past few decades. The growing desire for better indoor environmental quality in aquatic centres has resulted in a marked increase in energy consumption in this sector. Community expectations in relation to aquatic centres are rising and these spaces are associated with wellness and health. Energy consumption in indoor swimming pool buildings is high due to the high indoor air temperatures, increased ventilation heat losses and the need to disinfect water. This study investigates the energy consumption and indoor environmental quality of seven aquatic centres in Australia. The construction and various energy consuming systems of the facilities are analysed and compared against the energy consumption. Thermal comfort data is collected through measuring the indoor environmental parameters. Building envelopes were found to be leaky in most of the buildings resulting in energy wastage. The main indicators for energy consumption were gross floor area, area of pool surface, and number of visitors. It was found that the set point temperatures were significantly high in some of the buildings resulting in high level of discomfort for the spectators and staff.

A pixel-based approach to estimation of solar energy potential on building roofs

Precise estimation of solar energy on building roofs plays a critical role in sustainable development and renewable energy consumption of high-density human habitats. Conventional solar radiation models based on costly Light Detection and Ranging (LiDAR) data are only adequate for existing buildings, not for future construction areas. In this paper, a pixel-based methodology is constructed for estimating solar energy potential over roofs. Buildings with flat roofs in a newly planned construction area are chosen as a case study. The solar radiation at a certain cell is mathematically formulated in the pixel unit, and its yields over a certain time period are calculated by considering multiple instantaneous solar irradiances and are visually presented by image processing. Significant spatial and temporal variations in solar radiation are measured. Within the study area, the maximum and minimum annual radiation yields are estimated at 4717.72 MJ/m2/year and 342.58 MJ/m2/year respectively. Radiation contour lines are then mapped for outlining installation ranges of various solar devices. For each apartment building, around 20% of roof areas can obtain 4500 MJ/m2/year or more solar radiation yields. This study will benefit energy investors and urban planners in accurately predicting solar radiation potential and identifying regions with high radiation over building roofs. The results can be utilised in government policies and urban planning to raise awareness of the use of renewable energy sources.

Using small reverse cycle air conditioners in relocatable classrooms - a case study

A 9-month study of four relocatable school buildings, each retro-fitted with small reverse cycle air conditioners (ACs), was conducted to investigate their effectiveness in heating and cooling the classrooms. A comparison with data from previous studies found the energy used by the ACs for heating these temporary classrooms was only 19–20% of the energy used by individual gas heaters installed in permanent classrooms. When equipment efficiencies were considered, the AC units supplied 20–27% less energy to heat the classrooms. The possible reasons for this reduction in supplied energy are explored in this paper. CO2 emissions for the AC units in heating mode, however, were calculated to be 16% greater than for individual gas heaters. The AC units were also used for cooling and on an average the total annual energy consumption for heating and cooling was found to be 11.6 kWh m−2. Responses to a small survey of staff and students about the use and operation of the conditioners are presented. Their responses were more favourable than the predictions of comfort levels in the classrooms using the Predicted Mean Vote–Predicted Percentage of Dissatisfaction (PMV–PPD) model, which indicated “uncomfortable” conditions on average summer days at 3:00 p.m. and average winter days at 10:00 a.m. Background noise levels in the classrooms with the air conditioners in use were above the recommended maximum design level of 45 dB(A); levels of up to 65 dB(A) were measured.

Life-cycle energy analysis of building integrated photovoltaic systems (BiPVs) with heat recovery unit

Building integrated photovoltaic (BiPV) systems generate electricity, but also heat, which is typically wasted and also reduces the efficiency of generation. A heat recovery unit can be combined with a BiPV system to take advantage of this waste heat, thus providing cogeneration. Two different photovoltaic (PV) cell types were combined with a heat recovery unit and analysed in terms of their life-cycle energy consumption to determine the energy payback period. A net energy analysis of these PV systems has previously been performed, but recent improvements in the data used for this study allow for a more comprehensive assessment of the combined energy used throughout the entire life-cycle of these systems to be performed. Energy payback periods between 4 and 16.5 years were found, depending on the BiPV system. The energy embodied in PV systems is significant, emphasised here due to the innovative use of national average input–output (I–O) data to fill gaps in traditional life-cycle inventories, i.e. hybrid analysis. These findings provide an insight into the net energy savings that are possible with a well-designed and managed BiPV system.

Energy use in relocatable classrooms

A nine month study of four relocatables in Melbourne, each containing two classrooms and retro-fitted with various models of small reverse cycle air conditioner, found that the energy used for heating these "temporary" classrooms was only 19-20% of the energy used in permanent classrooms fitted with individual gas heaters. The energy delivered to the relocatables was calculated to be 20-27% less than that delivered to the permanent classrooms, when equipment efficiencies were considered. The reasons for this difference are explored in this paper. It was found superior insulation levels and reduced comfort levels appear to be the key factors responsible for the reduced annual heating energy demand. CO² emissions for the AC units in heating mode were calculated to be 16% greater than for individual gas heaters. The AC units were also used for cooling and on average the total annual energy consumption for heating and cooling was found to be just over 700 kWh or 11.6 kWh ^-2 m.