• Energy Research
• Open Access close
• Closed Access close
• US close
• AU close
• EC close

The objectives of the hot-gas cleanup (HGC) work on the transport reactor demonstration unit (TRDU) located at the Energy {ampersand} Environmental Research Center (EERC) is to demonstrate acceptable performance of hot-gas filter elements in a pilot-scale system prior to long-term demonstration tests. The primary focus of the experimental effort in the 2-year project is the testing of hot-gas filter element performance (particulate collection efficiency, filter pressure differential, filter cleanability, and durability) as a function of temperature and filter face velocity during short-term operation (100-200 hours). The filter vessel is used in combination with the TRDU to evaluate the performance of selected hot-gas filter elements under gasification operating conditions. This work directly supports the power systems development facility (PSDF) utilizing the M.W. Kellogg transport reactor located at Wilsonville, Alabama (1) and, indirectly, the Foster Wheeler advanced pressurized fluid-bed combustor, also located at Wilsonville.

The pulsers used in most of the induction linacs evolved from the very large body of work that was done in the U.S. and Great Britain during the development of the pulsed magnetron for radar. The radar modulators started at {approx}100 kW and reached >10 MW by 1945. A typical pulse length was 1 {mu}s at a repetition rate of 1,000 pps. A very comprehensive account of the modulator development is Pulse Generators by Lebacqz and Glasoe, one of the Radiation Laboratory Series. There are many permutations of possible modulators, two of the choices being tube type and line type. In earlier notes I wrote that technically the vacuum tube pulser met all of our induction linac needs, in the sense that a number of tubes, in series and parallel if required, could produce our pulses, regulate their voltage, be useable in feed-forward correctors, and provide a low source impedance. At a lower speed, an FET array is similar, and we have obtained and tested a large array capable of >10 MW switching. A modulator with an electronically controlled output only needs a capacitor for energy storage and in a switched mode can transfer the energy from the capacitor tomore » the load at high efficiency. Driving a full size Astron induction core and a simulated resistive 'beam load' we achieved >50% efficiency. These electronically controlled output pulses can produce the pulses we desire but are not used because of their high cost. The second choice, the line type pulser, visually comprises a closing switch and a distributed or a lumped element transmission line. The typical switch cannot open or stop conducting after the desired pulse has been produced, and consequently all of the initially stored energy is dissipated. This approximately halves the efficiency, and the original cost estimating program LIACEP used this factor of two, even though our circuits are usually worse, and even though our inveterate optimists often omit it. The 'missing' energy is that which is reflected back into the line from mismatches, the energy left in the accelerator module's capacitance, the energy lost in the switch during switching and during the pulse, and the energy lost in the pulse line charging circuit. For example, a simple resistor-limited power supply dissipates as much energy as it delivers to the pulse forming line, giving a factor if two by itself, therefore efficiency requires a more complicated charging system.« less

The US Department of Energy (DOE) is using the total fuel cycle analysis (TFCA) methodology to evaluate energy choices. The National Energy Strategy (NES) identifies TFCA as a tool to describe and quantify the environmental, social, and economic costs and benefits associated with energy alternatives. A TFCA should quantify inputs and outputs, their impacts on society, and the value of those impacts that occur from each activity involved in producing and using fuels, cradle-to-grave. New fuels and energy technologies can be consistently evaluated and compared using TFCA, providing a sound basis for ranking policy options that expand the fuel choices available to consumers. This study is limited to creating an inventory of inputs and outputs for three transportation fuels: (1) reformulated gasoline (RFG) that meets the standards of the Clean Air Act Amendments of 1990 (CAAA) using methyl tertiary butyl ether (MTBE); (2) gasohol (E10), a mixture of 10% ethanol made from municipal solid waste (MSW) and 90% gasoline; and (3) E95, a mixture of 5% gasoline and 95% ethanol made from energy crops such as grasses and trees. The ethanol referred to in this study is produced from lignocellulosic material-trees, grass, and organic wastes -- called biomass. The biomass is converted to ethanol using an experimental technology described in more detail later. Corn-ethanol is not discussed in this report. This study is limited to estimating an inventory of inputs and outputs for each fuel cycle, similar to a mass balance study, for several reasons: (1) to manage the size of the project; (2) to provide the data required for others to conduct site-specific impact analysis on a case-by-case basis; (3) to reduce data requirements associated with projecting future environmental baselines and other variables that require an internally consistent scenario.

Among the sufficiency, efficiency, and renewable frameworks for reducing energy use and energy-related carbon emissions, Building Energy Sufficiency (BES) is gaining attention from policy makers and engineers. Despite the significant role of the building sector in the success of national energy and climate plans, there is a lack of research on the drivers, technologies, and effective policy instruments required to achieve BES in the building operational phase. To fill this gap, this study presents a systematic review of the definition and paradigm of BES and concludes that BES should address both occupant demand and energy or emissions requirements simultaneously. The characteristics of occupant demand in building services are divided into four dimensions: time and space, quality and quantity, control and adjustment, and flexibility. Technical options regarding the building architecture, the envelope system, and the building energy system are reviewed. Finally, policy implications and recommendations are discussed. The multiple benefits and multidisciplinary nature of BES justify further research and accelerated policy implementation in developed and developing countries.

Rising demand and limited production of electricity are instrumental in spreading the awareness of cautious energy use, leading to the global demand for energy-efficient buildings. This compels the construction industry to smartly design and effectively construct these buildings to ensure energy performance as per design expectations. However, the research tells a different tale: energy-efficient buildings have performance issues. Among several reasons behind the energy performance gap, occupant behavior is critical. The occupant behavior is dynamic and changes over time under formal and informal influences, but the traditional energy simulation programs assume it as static throughout the occupancy. Effective behavioral interventions can lead to optimized energy use. To find out the energy-saving potential based on simulated modified behavior, this study gathers primary building and occupant data from three energy-efficient office buildings in major cities of Pakistan and categorizes the occupants into high, medium, and low energy consumers. Additionally, agent-based modeling simulates the change in occupant behavior under the direct and indirect interventions over a three-year period. Finally, energy savings are quantified to highlight a 25.4% potential over the simulation period. This is a unique attempt at quantifying the potential impact on energy usage due to behavior modification which will help facility managers to plan and execute necessary interventions and software experts to develop effective tools to model the dynamic usage behavior. This will also help policymakers in devising subtle but effective behavior training strategies to reduce energy usage. Such behavioral retrofitting comes at a much lower cost than the physical or technological retrofit options to achieve the same purpose and this study establishes the foundation for it.

It has been established in numerous cases that proteins which are exported from Escherichia coli are synthesized on membrane-bound polysomes in precursor forms which are proteolytically cleaved to generate the mature species. Here we present evidence that at least one step in the export of proteins requires energy. Energy requirements for processing of the precursors of both the M13 coat protein [Date, T., Zwizinski, C., Ludmerer, S., and Wickner, W. (1980) Proc. Natl Acad. Sci. USA, 77, 827-831; Date, T., Goodman, J. M., and Wickner, W. T. (1980) Proc. Natl Acad. Sci. USA, 77, 4669-4673] and the B subunit of heat-labile enterotoxin [Palva, T., Hirst, T. R., Hardy, S. J. S., Holmgren, J., and Randall, L. L. (1981) J. Bacteriol. in the press] have been demonstrated previously. An energy requirement for the proteolytic processing of an additional five exported proteins is reported here. Studies utilizing an uncA mutant suggest that the form of energy required is proton-motive force. Thus an energized membrane is probably essential for export of most periplasmic and outer membrane proteins.

Abstract Power-to-gas (PtG), as a promising technology proposed to store surplus renewable energy (RE), can hardly be commercialized for its low profitability. In this paper, three approaches are proposed in this paper to enhance the profitability of the PtG. Firstly, a cooperative union containing PtG is proposed and its sustainability analysis is undertaken based on Shapley Value method. Secondly, the PtG reaction heat, as an essential by-product of PtG which is valuable and therefore requires further study, is fully exploited for district heating in the operation of regional integrated energy system, which is solved by an improved SOCP method. Thirdly, a symbiosis cooperation mode is designed for wind power and PtG to enhance the benefit of PtG through optimization-based trading strategy, which is a MINLP model and solved by Big-M method. The results show that the daily profit of PtG is significantly increased with the cooperative union as the symbiosis cooperation mode can produce a 15.1% profit lift, meanwhile, exploitation of reaction heat can produce an 8.6% profit lift. Finally, our study reveals the conflict of interest between wind power and the cogeneration. A sensitivity study on the proportion of reaction heat used for district heating is performed to verify the mutually beneficial relation between PtG and the cogeneration. The findings of this paper can guide the commercialization of PtG.

Thermal ratcheting is a critical phenomenon associated with the cyclic operation of dual-medium thermocline tanks in solar energy applications. Although thermal ratcheting poses a serious impediment to thermocline operation, this failure mode in dual-medium thermocline tanks is not yet well understood. To study the potential for the occurrence of ratcheting, a comprehensive model of a thermocline tank that includes both the heterogeneous filler region as well as the composite tank wall is formulated. The filler region consists of a rock bed with interstitial molten salt, while the tank wall is composed of a steel shell with two layers of insulation (firebrick and ceramic). The model accounts separately for the rock and molten-salt regions in view of their different thermal properties. Various heat loss conditions are applied at the external tank surface to evaluate the effect of energy losses to the surroundings. Hoop stresses, which are governed by the magnitude of temperature fluctuations, are determined through both a detailed finite-element analysis and simple strain relations. The two methods are found to yield almost identical results. Temperature fluctuations are damped by heat losses to the surroundings, leading to a reduction in hoop stresses with increased heat losses. Failure is prevented when the peak hoop stress is less than the material yield strength of the steel shell. To avoid ratcheting without incurring excessive energy loss, insulation between the steel shell and the filler region should be maximized.