Dynamic characteristics and efficiency of a fluidized bed heat treatment process

The dynamic characteristics of gas bubbles in fluidized beds are important to determine the heat and mass transfer rates at component surfaces and the treated profiles of components. They also have great impact on the components’ structural, mechanical and physical properties. However, it has been very difficult to monitor those characteristics dynamically. In this paper, a specifically designed fluidized bed was introduced to facilitate the capturing of its dynamic characteristics and a new video image processing and analysis algorithm was developed. The algorithm is robust and adaptive in terms of locating both bubbles and components in beds with a single or multiple components. It has many advantages in dynamic characterization of gas bubbles and monitoring component treatment. By using this algorithm, the properties of gas bubbles over any period of time can be accurately obtained. This technology will provide a potential on-line dynamic monitoring and quality control system for the chemical heat treatment processes with fluidized beds.

Effect of load pattern on solar-boosted heat pump water heater performance

The performance of a solar-boosted heat pump water heater (HPWH) operating under full load and part load conditions was determined in an outdoor experimental study. The system utilised flat unglazed aluminium solar evaporator panels to absorb solar and ambient energy. Absorbed energy was transferred to the water tank by means of the heat pump and a wrap around condenser coil on the outside of the tank. The system COP was found to be in the range of 5–7 under clear daytime conditions and 3–5 under clear night-time conditions. Using part load testing of the HPWH system it was found that concentrating the coils in the lower portion of the tank could increase the efficiency of the condenser coil. It was also shown that there exists a generalised linear relationship that can be used to describe the system COP in terms of the temperature difference between the water in the storage tank and the ambient air.

Seasonal performance rating of heat pump water heaters

Seasonal performance evaluation methods for water heaters are reviewed and an experimental method for rating air-source heat pump water heaters is presented. The rating method is based on measured heat pump performance during heat-up operation of particular products rather than a generic simulation model of heat pump performance. The measured performance is used in a correlation model of the heat pump unit in an annual load-cycle system performance simulation based on the TRNSYS simulation package.

Development of a building integrated photovoltaic/thermal solar energy cogeneration system

Using renewable energy sources for onsite cogeneration from structural building elements is a relatively new concept and is gaining considerable interest. In this study the design, development, manufacturing and testing of a novel building integrated photovoltaic/thermal (BIPVT) solar energy cogeneration system is discussed.

Adhesives (ADH), resistance seam welding (RSW) and autoclaving (ATC) were identified as the most appropriate for fabricating BIPVT roofing panels. Of these manufacturing methods ADH was found to be most suitable for low volume production systems due to its low capital cost.

A prototype panel, fabricated using ADH methods, exhibited good thermal performance. It was also shown that BIPVT performance could be theoretically predicted using a one dimensional heat transfer model and showed excellent agreement with experimental data. The model was used to suggest further design improvements. Finally, a transient simulation of the BIPVT was performed in TRNSYS and is used to illustrate the benefits of the system.

Evaluation of heat stress indices using physiological comparisons in an alumina refinery in a sub-tropical climate

The production of alumina involves the use of a process known as the Bayer process. This method involves the digestion of raw bauxite in sodium hydroxide at temperatures around 250°C. The resultant pregnant liquor then goes through a number of filtering and precipitation processes to obtain the aluminium oxide crystals which are then calcined to obtain the final product. The plant is situated in a sub tropical climate in Northern Australia and this combined with the hot nature of the process results in a potential for heat related illnesses to develop. When assessing a work environment for heat stress a heat stress index is often employed as a guideline and to date the Wet Bulb Globe Temperature (WBGT) has been the recommended index. There have been concerns over the past that the WBGT is not suited to the Northern Australian climate and in fact studies in other countries have suggested this is the case. This study was undertaken in the alumina plant situated in Gladstone Queensland to assess if WBGT was in fact the most suitable index for use or if another was more applicable. To this end three indices, Wet Bulb Globe Temperature (WBGT), Heat Stress Index (HSI) and Required Sweat Rate (SWreq) were compared and assessed using physiological monitoring of heart rate and surrogate core temperature. A number of different jobs and locations around the plant were investigated utilising personal and environmental monitoring equipment. These results were then collated and analysed using a computer program written as part of the study for the manipulation of the environmental data . Physiological assessment was carried out using methods approved by international bodies such as National Institute for Occupational Safety & Health (NIOSH) and International Standards Organisation (ISO) and incorporated the use of a ‘Physiological Factor’ developed to enable the comparison of predicted allowable exposure times and strain on the individual. Results indicated that of the three indices tested, Required Sweat Rate was found to be the most suitable for the climate and in the environment of interest. The WBGT system was suitable in areas in the moderate temperature range (ie 28 to 32°C) but had some deficiencies above this temperature or where the relative humidity exceeded approximately 80%. It was however suitable as a first estimate or first line indicator. HSI over-estimated the physiological strain in situations of high temperatures, low air flows and exaggerated the benefit of artificial air flows on the worker in certain environments ie. fans.

Reducing energy consumption of vehicle air conditioning system by an energy management system

This paper presents an energy management system to reduce the energy consumption of a vehicle when its air conditioning system is in use. The system controls the mass flow rate of the air by dynamically adjusting the blower speed and air-gates opening under various heat and loads circumstances. Simulations were conducted for a travelling vehicle operating the air conditioning system without and with the developed energy management system. The results show that the comfort temperature within the cabin room is achieved for reduced amount of energy consumption.

Incorporation of a hybrid cooling system in water cooled power stations to reduce water and energy consumptions

Water shortage is a major problem facing the power industry in many nations around the world. The largest consumer of water in most power plants is the wet cooling tower. To assist water and energy saving for thermal power stations using conventional evaporative wet cooling towers, a hybrid cooling system is proposed in this paper. The hybrid cooling system may consists of all or some of an air pre-cooler, heat pump, heat exchangers, and adsorption chillers together with the existing cooling tower. The hybrid cooling system described in the paper, consisting of a metal hydride heat pump operating in conjunction with the existing wet cooling tower, is capable of achieving water saving by reducing the temperature of warm water entering the cooling tower. Cooler inlet water temperatures effectively reduce the cooling load on existing towers. This will ultimately reduce the amount of water lost to the air by evaporation whilst still achieving the same cooling output. At the same time, the low grade waste energy upgraded by the metal hydride heat pump, in the process of cooling the water, can be used to replace the bleed of steam for the lower stage feed heaters which will increase overall cycle efficiency.

The type II secretion system and its ubiquitous lipoprotein substrate, SsIE are required for biofilm formation and virulence of enteropathogenic escherichia coli

Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrhea in infants in developing countries. We have identified a functional type II secretion system (T2SS) in EPEC that is homologous to the pathway responsible for the secretion of heat-labile enterotoxin by enterotoxigenic E. coli. The wild-type EPEC T2SS was able to secrete a heat-labile enterotoxin reporter, but an isogenic T2SS mutant could not. We showed that the major substrate of the T2SS in EPEC is SslE, an outer membrane lipoprotein (formerly known as YghJ), and that a functional T2SS is essential for biofilm formation by EPEC. T2SS and SslE mutants were arrested at the microcolony stage of biofilm formation, suggesting that the T2SS is involved in the development of mature biofilms and that SslE is a dominant effector of biofilm development. Moreover, the T2SS was required for virulence, as infection of rabbits with a rabbit-specific EPEC strain carrying a mutation in either the T2SS or SslE resulted in significantly reduced intestinal colonization and milder disease.

Twitter tsunami early warning network : a social network analysis of Twitter information flows

In the aftermath of earthquakes, tsunamis, such as the 2011 Great East Japan Tsunami, caused enormous damage around the world. With the extreme disaster events of the past, nations improved disaster preparedness and response through sensors and tsunami early warning systems. Even with system usage, however, governments still need to warn the targeted citizens – who may be anywhere within the vulnerable areas – of predicted tsunami and ordered mass evacuations within a very limited lead time. While social media research is on the rise outside the domain of social networking, very little is written about Twitter use for tsunami early warning. In this research, therefore, we examined the utility of Twitter as a tsunami early warning network, which engages citizens and disaster management agencies in diffusing disaster information. We conducted a social network analysis of Twitter information flows among the central disaster warning agency’s Twitter followers during the 2012 Indonesia Earthquake.

Seasonal coolth storage system for residential buildings in Australia

Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night. An evaluation of the night sky cooling system is present for a residential building in three cities of Australia, namely Alice Springs, Darwin and Melbourne. The system comprises an unglazed flat plate solar collector integrated with borehole storage. It uses night sky radiation to reduce the temperature of the ground near to the boreholes. The system was simulated with TRNSYS, a transient simulation program. The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations. Borehole lengths of 270, 318 and 106 m are required for coolth storage with 90, 260 and 14 m2 collector area for heat rejection in Alice Springs, Darwin and Melbourne, respectively. At the 20th simulation year, the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs, and 2.8 in Darwin and Melbourne.

Supplementing cold plasma with heat enables doping and nano-structuring of metal oxides

Nitrogen doped SnO2 polycrystalline nanostructures were produced from commercial SnO powders in a new system that combines a low-temperature plasma with heating. The method has the potential to improve the initial efficiency and the cycling performance of SnO2 anodes in Li-ion batteries. With this system, the temperature of the SnO to SnO2 conversion was lowered from 430 to 320 °C, up to 5 at% of doped nitrogen was detected and a nano-scale polycrystalline structure was observed in the product. Combining heat and low-pressure plasma is a promising approach for the production and treatment of enhanced energy storage materials.

Alzheimer's Abeta fused to green fluorescent protein induces growth stress and a heat shock response

The 42 amino acid Alzheimer's Aβ peptide is involved in the progression of Alzheimer's disease. Here we describe the effects of intracellular Aβ, produced through its attachment to either end of a green fluorescent protein, in yeast. Cells producing Aβ exhibited a lower growth yield and a heat shock response, showing that Aβ fusions promote stress in cells and supporting the notion that intracellular Aβ is a toxic molecule. These studies have relevance in understanding the role of Aβ in the death of neuronal cells, and indicate that yeast may be a new tractable model system for the screening for inhibitors of the stress caused by Aβ.

The study of adsorption mechanism of mixed pesticides prometryne-acetochlor in the soil-water system

This article reported adsorption mechanism of mixed pesticides Prometryne-Acetochlor (PA) in soil. Thermodynamics and adsorption isotherms were used to preliminarily evaluate adsorption force, and IR and XRD were used to characterize adsorption characteristics between Prometryne/Acetochlor (PA) and soil, The result shows that adsorption isotherms is F-type, adsorptive heat are 9.57 kJ/mol and -93.83 kJ/mol of prometryne and acetochlor respectively. Hydrogen bonds also had been confirmed by IR and XRD analysis. The results can provide a theoretical support to the use of mixed pesticides agents.

Integrated model of horizontal earth pipe cooling system for a hot humid climate

Energy efficiency of a building has become a major requirement since the building sector produces 40%-50% of the global greenhouse gas emissions. This can be achieved by improving building’s performance through energy savings, by adopting energy efficient technologies and reducing CO2 emissions. There exist several technologies with less or no environmental impact that can be used to reduce energy consumption of the buildings. Earth pipe cooling system is one of them, which works with a long buried pipe with one end for intake air and the other end for providing air cooled by soil to the building. It is an approach for cooling a room in a passive process without using any habitual mechanical unit. The paper investigates the thermal performance of a horizontal earth pipe cooling system in a hot and humid subtropical climatic zone in Queensland, Australia. An integrated numerical model for the horizontal earth pipe cooling system and the room (or building) was developed using ANSYS Fluent to measure the thermal performance of the system. The impact of air temperature, soil temperature, air velocity and relative humidity on room cooling performance has also been assessed. As the soil temperature was below the outdoor minimum temperature during the peak warming hours of the day, it worked as an effective heat sink to cool the room. Both experimental and numerical results showed a temperature reduction of 1.11oC in the room utilizing horizontal earth pipe cooling system which will assist to save the energy cost in the buildings.

Analytical thermal study on nonlinear fundamental heat transfer cases using a novel computational technique

In this paper a novel computational technique called Parameterized Perturbation Method (PPM) is used to obtain the solutions of nonlinear fundamental heat conduction equations. Three well known problems in the area of heat transfer are addressed to be solved. An analytical investigation is carried out for: (a) the temperature distribution in a fin with a temperature-dependent thermal conductivity, (b) the cooling of the lumped system with variable specific heat, and (c) the temperature distribution of a convective-radiative fin. The validity of the results of PPM solution was verified via comparison with numerical results obtained using a fourth order Runge-Kutta method. These comparisons revealed that PPM is a powerful approach for solving these problems. Also, the results showed that the main attributions of this method are very straightforward calculations and low computational burden compared to previous analytical and numerical approaches.