A useful and convenient rheological test for polymer melt characterisation

A useful and convenient rheological test for polymer melt characterisatio

Energy conservation in buildings : cogeneration and cogeneration coupled with thermal-energy storage

Energy-conservation opportunity in an institutional building is studied through cogeneration with double-effect absorption chiller. Both, technical and economical feasibility is evaluated and presented. The typical electrical energy and cooling-load demand profiles of the buildings concerned are determined. Payback period, internal rate-of-return (IRR), net present value (NPV) and net profit of the Institute is determined through cash-flow analysis. Then, cogeneration coupling with thermal energy storage (TES) is studied and its technical and economical feasibility is evaluated and compared with that of cogeneration. On-site cogeneration with a double-effect absorption chiller provides a potential of at least 13% peak demand reduction and about a 16% savings in energy consumption. It provides IRR greater than 21% but the saving potential is limited by the low demand of co-generated chilled water within the community of the Institution. Cogeneration coupling with thermal energy storage offers a simple and economically more attractive approach for maximizing the utilization of co-generated chilled-water and shows 23% reduction in peak demand and a 21% savings in energy consumption. It provides a higher IRR, greater than 25%

Building energy management: Co-generation coupling with thermal energy storage

This paper is concerned with the feasibility study and evaluation of an energy savings opportunity in buildings energy management using co-generation coupling with thermal energy storage. Both the technical and economical feasibility is presented first for the co-generation and then compared with the co-generation using thermal energy storage. On-site cogeneration with double effect absorption chiller provides a potential of at least 13% peak demand reduction and about 16% savings in energy consumption. It provides an internal rate of return (IRR) greater than 21% but saving potential is limited by the low demand of co-generated chilled water within the community of the institution. Thermal energy storage coupling with co-generation offers a simple and economically more attractive approach for maximizing the utilization of cogenerated chilled water and shows 23% reduction in peak demand and 21% savings in energy consumption. It provides higher IRR, greater than 25%

Buildings energy simulation using energy express : a case study on sub-tropical Central Queensland University (CQU) buildings

The strategies of buildings energy management can be developed through energy audit, analysis and simulation. Currently, different end-users of CQU buildings such as heating, ventilating and air conditioning (HVAC) units, electrical appliances, etc do not take full advantage of local sub-tropical climatic conditions. Therefore, climate-responsive strategies need to be implemented in order to take full advantage of the positive climate attribute of sub-tropical climate regarding efficient energy management and conservation measures. This study is conducted on a three-story library building of CQU. HVAC systems were selected for practical operational energy conservation measures (ECM) to take advantages of hot and humid subtropical climate. A baseline energy consumption profile of the building is simulated using building energy simulation software called Energy Express (EE). The simulated results are then validated with energy audit and on-site metered data. The means to utilize environmental conditions to improve building energy efficiency is investigated. Variable air volume (VAV) system as an energy conservation option is investigated and compared with existing constant air volume (CAV) system. This study found that about 12% energy savings could be achieved by replacing CAV system with VAV system as an option for energy retrofitting, and hence recommended to CQU management for consideration

An improved boundary layer scaling with ramp heating on a sloping plate

A scaling analysis for the natural convection boundary layer adjacent to an inclined semi-infinite plate subject to a non-instantaneous heating in the form of an imposed wall temperature which increases linearly up to a prescribed steady value over a prescribed time is reported. The development of the boundary layer flow from start-up to a steady-state has been described based on scaling analyses and verified by numerical simulations. The analysis reveals that, if the period of temperature growth on the wall is sufficiently long, the boundary layer reaches a quasi-steady mode before the growth of the temperature is completed. In this mode the thermal boundary layer at first grows in thickness and then contracts with increasing time. However, if the imposed wall temperature growth period is sufficiently short, the boundary layer develops differently, but after the wall temperature growth is completed, the boundary layer develops as though the startup had been instantaneous. The steady state values of the boundary layer for both cases are ultimately the same

Thermofluid Modeling for Energy Efficiency Applications

Thermofluid Modeling for Sustainable Energy Applications provides a collection of the most recent, cutting-edge developments in the application of fluid mechanics modeling to energy systems and energy efficient technology. Each chapter introduces relevant theories alongside detailed, real-life case studies that demonstrate the value of thermofluid modeling and simulation as an integral part of the engineering process. Research problems and modeling solutions across a range of energy efficiency scenarios are presented by experts, helping users build a sustainable engineering knowledge base. The text offers novel examples of the use of computation fluid dynamics in relation to hot topics, including passive air cooling and thermal storage. It is a valuable resource for academics, engineers, and students undertaking research in thermal engineerin

Energy conservation measures in an institutional building by dynamic simulation using DesignBuilder

In this study, various energy conservation measures (ECMs) on heating, ventilating and airconditioning (HVAC) and lighting systems for a 4-storied building in subtropical (hot and humid climate)Central Queensland, Australia are evaluated using the simulation software called DesignBuilder (DB) which isbased on EnergyPlus (EP) simulation engine. Energy consumption profiles of existing systems i.e. base casescenario are analysed and simulated first then, the simulated results are verified by on-site measured data usingHobo data logger and smart meters. ECMs, namely variable air volume (VAV) systems instead of constant airvolume (CAV), photo electric dimming control system instead of general lighting, and double glazed lowemittance window instead of single glazed window are evaluated. The effect of indoor environment on theseECMs is also discussed. It has been found that the building considered in this study can save up to 26.5%energy without compromising occupancies thermal comfort by implementing the above mentioned ECMs intothe existing system

Sustainability in building environment : a review and analysis of mould growth in a subtropical climate

A literature review on environmental sustainability and airborne spore (mould) growth in buildings in a subtropical climate is presented first, then the characteristics of moulds in subtropical Central Queensland University (CQU) Rockhampton campus buildings are analysed. The fungal spore concentrations indoors and outdoors are compared and correlations between fungal spore concentrations and environmental parameters such as temperature and humidity are developed. Subtropical Central Queensland (Rockhampton) region’s have two main seasons: wet (December-March) and dry (May-October). Specific genera of moulds and total spores were identified and recovered colonies were counted from the airborne samples. The SPSS (Statistical Product and Service Solutions) software was used for nonparametric data analysis. Total airborne fungal spore concentrations were found highest in the dry season and lowest in the wet season and were positively correlated with relative humidity and temperature. Further studies are recommended for controlling moulds growth in subtropical climate

Green Roofs for Storm Water Management: A Review

The rapid urbanization and industrialization involve an unsustainable use of natural systems lead to various problems in cities. The urban hydrological system experiences fluctuating amount of surface runoff water when it rains heavily. It has been suggested that green roofs significantly mitigate storm water runoff generation even in tropical climate. Green roofs have become popular due to its proven benefits by mitigating urban heat island effects and protecting biodiversity. The annual rainfall and runoff relationship for green roofs is determined by the depth of the substrate. Water retention capacity mostly depends on substrate’s physical conditions such as dry or wetness. Generally 6 to 12 mm of rain is required for dry substrate to initiate runoff whereas response of wet conditions is mostly straight. Besides, there are some other factors affecting runoff dynamics such as type of green roof and its slope; age of green roof; type of vegetation; soil moisture characteristics and weather. The review indicates that there is not much research in green roofs performance over storm water runoff; hence there is a need for further research. This paper reviews and addresses the role of green roofs in urban storm water management

Performance analysis of rooftop greenery systems in Australian subtropical climate

This paper presents the performance analysis of an extensive rooftop greenery system (green roof) in buildings in the Australian Subtropical climate, both experimentally and computationally. The impact of green roof systems on building thermal performance, energy consumption and energy savings are examined and compared with a non-green roof system in both experimentally and using computer simulation software called DesignBuilder (DB). For the experimental study, a shipping container with a green roof was converted into an office building. For comparison purposes, another shipping container of the same dimensions without a green roof layer was constructed and decorated in an identical way to the green roof container. Two computational models, one for green roof and other for non-green roof were developed. A 4 °C temperature difference between the green roof and non-green roof containers was observed on a typical summer day. For the green roof, the maximum variation between the simulated and measured data was found to be 5% for temperature, 7.5% for humidity and 9.4% for energy consumption. The study found that an extensive green roof on a building in the Central Queensland sub-tropical climate (Australia) can achieve energy savings of 13.65% (simulated) and 11.70% (measured) compared to a non-green roof