Life Cycle Costing Applications in Sustainable Building

Life Cycle Costing (LCC) which is defined ISO 15686-5:2005 is used to assess the sustainable and renewable technology used in building. The results indicate that the premium cost of sustainable/renewable technology in building is surprisingly lower than many have expected. The life time saving benefits are mainly coming from energy savings. However benefits might also come from improved indoor environmental quality, greater employee comfort/productivity, reduced employee health costs and lower operations and maintenance costs. These benefits will normally greatly exceed any additional upfront premium costs. The information derived from this study will assist people to be aware of the life cycle cost and benefit of sustainable and renewable technology in building. It will also provide the architect/engineer the information about energy conservation potential acquired via energy saving and conservation

CONSTRUCTION EDUCATION REQUIREMENTS FOR ACHIEVING LEVEL 2 AND 3 BIM

The Architecture Engineering Construction (AEC) Industry is well noted for its fragmented nature, leading to several flaws in communication and information processing, which have led to a proliferation of adversarial relationships amongst project participants, thereby affecting the integrity of design information throughout the project life cycle. Likewise, Construction Education is bedevilled by multitudinous issues due to its practice-based, interdisciplinary nature of the industry, its professional and institutional history, and its evolving context and composition. These challenges have influenced the purpose of construction as well as the requirements or strategies needed to achieve it. The purpose of this paper is to examine the nature of Construction Education and learning requirements for successful training and implementation of Level 2 (with the aid of a process map) and also of Level 3, to meeting the ever-changing nature of the AEC industry. This process map seeks to identify the educational requirements for existing industry practitioners and for fresh graduates entering into the industry. In order to achieve this aim, a case study methodology was adopted using semi-structured interviews with BIM experts in purposively selected organisations in the UK, which were further analysed using single case narrative and cross-case synthesis techniques. The BIM sub-processes at each project phase of the construction process were extracted from the interviews conducted. Then the process map linking all the BIM activities in the project was developed. In conclusion, the process map formalises the knowledge and skills set required to successfully implement Level 2 and 3 BIM, facilitating project collaboration, communication flow and agreement amongst project participants on construction processes throughout the project lifecycle. The finding of this research are highly aligned with the seminal literature which argued that new skills required for the creation and management of a BIM model fall into the three categories of technological tools, organisational processes, and project team roles and responsibilities, and that these three skill sets contribute to the success of the entire BIM project and adoption in any organisation

Cloud tracking with optical flow for short-term solar forecasting

A method for tracking and predicting cloud movement using ground based sky imagery is presented. Sequences of partial sky images, with each image taken one second apart with a size of 640 by 480 pixels, were processed to determine the time taken for clouds to reach a user defined region in the image or the Sun. The clouds were first identified by segmenting the image based on the difference between the blue and red colour channels, producing a binary detection image. Good features to track were then located in the image and tracked utilising the Lucas-Kanade method for optical flow. From the trajectory of the tracked features and the binary detection image, cloud signals were generated. The trajectory of the individual features were used to determine the risky cloud signals (signals that pass over the user defined region or Sun). Time to collision estimates were produced based on merging these risky cloud signals. Estimates of times up to 40 seconds were achieved with error in the estimate increasing when the estimated time is larger. The method presented has the potential for tracking clouds travelling in different directions and at different velocities

The X-ray Line Emission from the Supernova Remnant W49B

The Galactic supernova remnant W49B has one of the most impressive X-ray emission line spectra obtained with the Advanced Satellite for Cosmology and Astronomy (ASCA). We use both plasma line diagnostics and broadband model fits to show that the Si and S emission lines require multiple spectral components. The spectral data do not necessarily require individual elements to be spatially stratified, as suggested by earlier work, although when ASCA line images are considered, it is possible that Fe is stratified with respect to Si and S. Most of the X-ray emitting gas is from ejecta, based on the element abundances required, but is surprisingly close to being in collisional ionization equilibrium. A high ionization age implies a high internal density in a young remnant. The fitted emission measure for W49B indicates a minimum density of 2 cm^-3, with the true density likely to be significantly higher. W49B probably had a Type Ia progenitor, based on the relative element abundances, although a low-mass Type II progenitor is still possible. We find persuasive evidence for Cr and possibly Mn emission in the ASCA spectrum--the first detection of these elements in X-rays from a cosmic source.Comment: 22 pages incl 8 postscript figures, to appear in Ap

Limits of the cylindrical absorber design for a sodium receiver

The applicability of the cylindrical arrangement of vertical tube banks is evaluated for liquid sodium concentrating solar thermal receivers and compared with a molten salt reference case through a series of parametric studies. It is shown that sodium receivers experience less thermo-elastic stress load and can operate under higher flux which presents advantages in terms of size reduction and efficiency. While the cylindrical receiver configuration cannot reach the efficiency target of 91% in a high temperature configuration (480 °C to 640 °C), there is potential to improve efficiency by improving heliostat field optics. Flux limitations due to thermo-elastic stresses are less stringent due for sodium receivers due to the better heat transfer properties, and consequently better heliostat field optics would benefit sodium receiver concepts more than molten salts ones

ECONOMICALLY OPTIMAL WILDFIRE INTERVENTION REGIMES

Wildfires in the United States result in total damages and costs that are likely to exceed billions of dollars annually. Land managers and policy makers propose higher rates of prescribed burning and other kinds of vegetation management to reduce amounts of wildfire and the risks of catastrophic losses. A wildfire public welfare maximization function, using a wildfire production function estimated using a time series model of a panel of Florida counties, is employed to simulate the publicly optimal level of prescribed burning in an example county in Florida (Volusia). Evaluation of the production function reveals that prescribed fire is not associated with reduced catastrophic wildfire risks in Volusia County Florida, indicating a short-run elasticity of -0.16 and a long-run elasticity of wildfire with respect to prescribed fire of -0.07. Stochastic dominance is used to evaluate the optimal amount of prescribed fire most likely to maximize a measure of public welfare. Results of that analysis reveal that the optimal amount of annual prescribed fire is about 3 percent (9,000 acres/year) of the total forest area, which is very close to the actual average amount of prescribed burning (12,700 acres/year) between 1994-99.Resource /Energy Economics and Policy,

Techno-economic optimisation of a sodium{ extendash}chloride salt heat exchanger for concentrating solar power applications

To enhance the economic viability of Concentrating solar power (CSP) plant, recent efforts have been directed towards employing high-temperature working fluid in the receiver and incorporating higher-efficiency power cycles. This work presents a techno-economic analysis of a sodium–chloride salt heat exchanger included in a sodium-driven CSP system with a supercritical CO2 power block. A quasi-steady state heat exchanger model was developed based on the TEMA guidelines, with the possibility of being customised in terms of media adopted, constraints, boundary conditions, and heat transfer correlations. The sodium–salt heat exchanger has been designed aiming at minimising the Levelized Cost of Electricity (LCOE) of the plant. The performance and the design of the proposed heat exchanger have been evaluated via multi-objective optimisation and sensitivity analyses. Results show that advanced CSP systems employing sodium and an indirect chloride salt storage can represent an economically viable solution and can drive towards the future goal of 5 USD/MWh. For a base-case 100 MWe plant with 12 h of storage, a LCOE of 72.7 USD/MWh and a capacity factor (CF) higher than 60% were reached. The techno-economic investigations showed the potential LCOE reduction of 6% as well as the flexibility and robustness of the heat exchanger model. The developed tool lays the groundwork to explore potential improvements of this new generation of CSP systems