High efficient OLED displays prepared with the air-gapped bridges on quantum dot patterns for optical recycling

OpenAIRE

Hyo-Jun Kim; Min-Ho Shin; Joo-Suc Kim; Se-Eun Kim; Young-Joo Kim

2017-01-01

An optically efficient structure was proposed and fabricated to realize high brightness organic light emitting diode (OLED) displays based on a white OLED prepared with the air-gapped bridges on the quantum dot (QD) patterns. Compared with a conventional white OLED display, in our experiments, the optical intensity of the proposed OLED display shows the enhancement of 58.2% in the red color and 16.8% in the green color after applying the air-gapped bridge structure on QD patterns of 20?wt% co...

Transparent Nanofibrous Mesh Self-Assembled from Molecular LEGOs for High Efficiency Air Filtration with New Functionalities.

Science.gov (United States)

Singh, Varun Kumar; Ravi, Sai Kishore; Sun, Wanxin; Tan, Swee Ching

2017-02-01

Alarming levels of particulate matter pollution in air pose a serious health threat in several countries, therefore intriguing a strong need for an economic and a viable technology of air filtration. Current air purification technology is rather expensive with certain types even having the risk of emitting hazardous by-products. The authors have developed a multifunctional air filter inspired from the nasal hairs possessing an ability to specifically trap/exhale the foreign particles and allergens while still letting the air flow. This design is achieved by introducing different functionalities at different dimensional scale employing a bottom-up approach starting with an organic molecule which is further self-organized to form nanoparticles and ultimately to a nanofibrous mesh. While the molecular building block inherently possesses the property of shielding Ultraviolet (UV) rays, the nanofibrous mesh built up from it aids in trapping the particulate matter while maintaining good air flow. By controlling the concentration of the organic molecule, the formation of fibers has been enabled in the nanoscale regime to obtain high particle-capture possibilities. The self-assembled nanofibrous filter thus designed has achieved a high filtration efficiency of ≈90% for the PM 2.5 particle in congruence with the ability to block the harmful UV radiations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

Science.gov (United States)

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV systems.

Directory of Open Access Journals (Sweden)

Bing Feng Ng

Full Text Available The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Phase I aging assessment of nuclear air-treatment system high efficiency particulate air and adsorbers

International Nuclear Information System (INIS)

Winegardner, W.K.

1996-01-01

A phase I aging assessment of high efficiency particulate air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the US Nuclear Regulatory Commission's Nuclear Plant Aging Research Program. Information was compiled concerning design features, failure experience, aging mechanisms, effects, and stressors, and monitoring methods. Over 1100 failures, or 12% of the filter installations, were reported as part of a US Department of energy survey. Investigators from other laboratories have suggested that aging could have contributed to over 80% of these failures. Several instances of impaired performance as the result of the premature aging of carbon were reported. Filter aging mechanisms range from those associated with particle loading to reactions that alter the properties of gaskets. Mechanisms that can lead to impaired adsorber performance include the loss of potentially available active sites as a result of the adsorption of moisture or pollutants. Stressors include heat, moisture, radiation, and airborne particles and contaminants. (orig.)

Efficiency of deodorant materials for ammonia reduction in indoor air

DEFF Research Database (Denmark)

Bivolarova, Mariya Petrova; Mizutani, Chiyomi; Melikov, Arsen Krikor

2014-01-01

A comparative study about the removability of ammonia gas in the air by activated carbon fiber (ACF) felt chemically treated with acid and a cotton fabric processed with iron phthalocyanine with copper (Cu) was performed in small-scale experiments. The test rig consisted of a heated plate and its...... proved activated carbon fiber felt with acid to be highly efficient in removing ammonia gas. Air temperature did not have profound effect on ACF performance. However, efficiency of the carbon fiber felt decreased when relative humidity was raised from 20 to 80%....

NEDO project reports. High performance industrial furnace development project - High temperature air combustion

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-21

For the purpose of reducing energy consumption, a NEDO project 'Developmental research on high efficiency industrial furnaces' was carried out from FY 1993 to FY 1999 by The Japan Industrial Furnaces Manufacturers Association, and the paper outlined the details of the project. Industrial furnaces handled in this R and D can bring 30% reduction of the energy consumption and approximately 50% NOx reduction, and were given the 9th Nikkei global environmental technology prize. In the study of combustion phenomena of high temperature air combustion, the paper arranged characteristics of flame, the base of gaseous fuel flame, the base of liquid fuel flame, the base of solid fuel flame, etc. Concerning high temperature air combustion models for simulation, fluid dynamics and heat transfer models, and reaction and NOx models, etc. As to impacts of high temperature air combustion on performance of industrial furnaces, energy conservation, lowering of pollution, etc. In relation to a guide for the design of high efficiency industrial furnaces, flow charts, conceptual design, evaluation method for heat balance and efficiency using charts, combustion control system, applicability of high efficiency industrial furnaces, etc. (NEDO)

NEDO project reports. High performance industrial furnace development project - High temperature air combustion

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-21

For the purpose of reducing energy consumption, a NEDO project 'Developmental research on high efficiency industrial furnaces' was carried out from FY 1993 to FY 1999 by The Japan Industrial Furnaces Manufacturers Association, and the paper outlined the details of the project. Industrial furnaces handled in this R and D can bring 30% reduction of the energy consumption and approximately 50% NOx reduction, and were given the 9th Nikkei global environmental technology prize. In the study of combustion phenomena of high temperature air combustion, the paper arranged characteristics of flame, the base of gaseous fuel flame, the base of liquid fuel flame, the base of solid fuel flame, etc. Concerning high temperature air combustion models for simulation, fluid dynamics and heat transfer models, and reaction and NOx models, etc. As to impacts of high temperature air combustion on performance of industrial furnaces, energy conservation, lowering of pollution, etc. In relation to a guide for the design of high efficiency industrial furnaces, flow charts, conceptual design, evaluation method for heat balance and efficiency using charts, combustion control system, applicability of high efficiency industrial furnaces, etc. (NEDO)

Research of Workflow Efficiency in HighEnthalpy Air Flow Compact Generators

Directory of Open Access Journals (Sweden)

V. Yu. Aleksandrov

2015-01-01

Full Text Available To test the combustion chambers (CC of high-speed ramjet engine (ramjet it is necessary to create the inlet conditions as realistic as possible, including the stagnation temperature T0, the Mach number M0, and the total airflow pressure p0. To achieve T0 = 1000 ... 2000 K is possible using a high-enthalpy airflow generator (HAG providing the fired air-heating and oxygen balance compensation.Due to strict weight and size restrictions imposed by the test conditions of the ramjet CC and bench equipment, there is a need to reduce HAG size and weight. For small HAG the relevant tasks are to organize effective workflow and ensure combustion stability, which can be solved directly at the developmental testing stage.The characteristic criterion of the workflow efficiency in HAG is the completed physicochemical combustion processes of the working fluid components. This is due to the fact that in the testing process a possible after-burning component of the working fluid in the flow path of the ramjet CC has a significant impact on the studied characteristics of the engine, thereby having a detrimental effect on the quality of the experiment.The examination of the workflow efficiency in HAG showed that the use of hydrogen as a fuel allows us to achieve a high degree of completing the physicochemical processes and reaching the specified conditions at the CC inlet to the ramjet under test. The use of hydrocarbon fuels reduces the completion degree of the workflow process in HAG and is accompanied by the development of pressure pulsations.The data obtained can be used when developing various HAGs, including those intended for testing the CC of ramjets for the prospective aircrafts.

High-efficiency plasma catalytic removal of dilute benzene from air

International Nuclear Information System (INIS)

Fan, Hong-Yu; Shi, Chuan; Li, Xiao-Song; Zhao, De-Zhi; Xu, Yong; Zhu, Ai-Min

2009-01-01

Achieving complete oxidation, good humidity tolerance and low energy cost is the key issue that needs to be addressed in plasma catalytic volatile organic compounds removal from air. For this purpose, Ag/HZSM-5 catalyst-packed dielectric barrier discharge using a cycled system composed of a storage stage and a discharge stage was studied. For dilute benzene removal from simulated air, Ag/HZSM-5 catalysts exhibit not only preferential adsorption of benzene in humid air at the storage stage but also almost complete oxidation of adsorbed benzene at the discharge stage. Five 'storage-discharge' cycles were examined, which suggests that Ag/HZSM-5 catalysts are very stable during the cycled 'storage-discharge' (CSD) plasma catalytic process. High oxidation rate of absorbed benzene as well as low energy cost can be achieved at a moderate discharge power. In an example of the CSD plasma catalytic remedy of simulated air containing 4.7 ppm benzene with 50% RH and 600 ml min -1 flow rate, the energy cost was as low as 3.7 x 10 -3 kWh m -3 air. This extremely low energy cost to remove low-concentration pollutants from air undoubtedly makes the environmental applications of the plasma catalytic technique practical.

Evaluation of seasonal exergy efficiency of air handing unit

Directory of Open Access Journals (Sweden)

Kęstutis Genys

2015-10-01

Full Text Available The article deals with the air handling unit seasonal exergy efficiency. TRNSYS simulation tool is used to evaluate it. The object of research is air treatment device used to treat an air for the ventilation of laboratory. The mathematical model of air handling unit using TRNSYS simulation tool was developed when the technical parameters of air handling unit and energy exchange in it were analysed. The developed model according to the made observations during the warm and cold periods was tested and validation of elements was performed. The simulation of air handling unit operation after the verification of reliability and permitted tolerances was performed. The control mechanisim which allows simulating the operation of air handling unit during cold and warm periods of the year was made. The mathematical algorithm for calculation of air handling unit exergy efficiency coefficient applying the principles of exergy analysis was developed. The seasonal exergy efficiency of air handling unit equal to 3.94 percent during the simulation was obtained.

Efficiency analysis of a hard-coal-fired supercritical power plant with a four-end high-temperature membrane for air separation

International Nuclear Information System (INIS)

Kotowicz, Janusz; Michalski, Sebastian

2014-01-01

The supercritical power plant analyzed in this paper consists of the following elements: a steam turbine, a hard-coal-fired oxy-type pulverized fuel boiler, an air separation unit with a four-end-type high-temperature membrane and a carbon dioxide capture unit. The electrical power of the steam turbine is 600 MW, the live steam thermodynamic parameters are 650°C/30 MPa, and the reheated steam parameters are 670°C/6 MPa. First of all the net efficiency was calculated as functions of the oxygen recovery rate. The net efficiency was lower than the reference efficiency by 9–10.5 pp, and a series of actions were thus proposed to reduce the loss of net efficiency. A change in the boiler structure produced an increase in the boiler efficiency of 2.5–2.74 pp. The range of the optimal air compressor pressure ratio (19–23) due to the net efficiency was also determined. The integration of all installations with the steam turbine produced an increase in the gross electric power by up to 50.5 MW. This operation enabled the replacement of the steam regenerative heat exchangers with gas–water heat exchangers. As a result of these alterations, the net efficiency of the analyzed power plant was improved to 5.5 pp less than the reference efficiency. - Highlights: • Analysis of a power plant with a “four-end” HTM for oxygen production was made. • Reorganization of the flue gas recirculation increased the boiler efficiency. • Optimization of the air compressor pressure ratio decreased the auxiliary power. • Replacement of the regenerative heat exchangers increased the gross electric power. • Comparison of the net efficiency of the analyzed and reference plants were made

Efficiency and Loading Evaluation of High Efficiency Mist Eliminators (HEME) - 12003

Energy Technology Data Exchange (ETDEWEB)

Giffin, Paxton K.; Parsons, Michael S.; Waggoner, Charles A. [Institute for Clean Energy Technology, Mississippi State University, 205 Research Blvd Starkville, MS 39759 (United States)

2012-07-01

High efficiency mist eliminators (HEME) are filters primarily used to remove moisture and/or liquid aerosols from an air stream. HEME elements are designed to reduce aerosol and particulate load on primary High Efficiency Particulate Air (HEPA) filters and to have a liquid particle removal efficiency of approximately 99.5% for aerosols down to sub-micron size particulates. The investigation presented here evaluates the loading capacity of the element in the absence of a water spray cleaning system. The theory is that without the cleaning system, the HEME element will suffer rapid buildup of solid aerosols, greatly reducing the particle loading capacity. Evaluation consists of challenging the element with a waste surrogate dry aerosol and di-octyl phthalate (DOP) at varying intervals of differential pressure to examine the filtering efficiency of three different element designs at three different media velocities. Also, the elements are challenged with a liquid waste surrogate using Laskin nozzles and large dispersion nozzles. These tests allow the loading capacity of the unit to be determined and the effectiveness of washing down the interior of the elements to be evaluated. (authors)

High efficiency cabin air filter in vehicles reduces drivers' roadway particulate matter exposures and associated lipid peroxidation.

Science.gov (United States)

Yu, Nu; Shu, Shi; Lin, Yan; She, Jianwen; Ip, Ho Sai Simon; Qiu, Xinghua; Zhu, Yifang

2017-01-01

Commuters who spend long hours on roads are exposed to high levels of traffic related air pollutants (TRAPs). Despite some well-known multiple adverse effects of TRAPs on human health, limited studies have focused on mitigation strategies to reduce these effects. In this study, we measured fine particulate matter (PM2.5) and ultrafine particle (UFP) concentrations inside and outside 17 taxis simultaneously while they were driven on roadways. The drivers' urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and malondialdehyde (MDA) concentrations just before and right after the driving tests were also determined. Data were collected under three driving conditions (i.e. no mitigation (NM), window closed (WC), and window closed plus using high efficiency cabin air filters (WC+HECA)) for each taxi and driver. The results show that, compared to NM, the WC+HECA reduced in-cabin PM2.5 and UFP concentrations, by 37% and 47% respectively (p health.

Indoor air quality handbook: for designers, builders, and users of energy efficient residences

International Nuclear Information System (INIS)

1982-09-01

The purpose of this handbook is to assist designers, builders, and users of energy efficient residences to achieve the goals of energy efficiency and maintenance of high indoor air quality simultaneously. The handbook helps in identifying and controlling potential problems of indoor air quality. It identifies sources and discusses effective ways to decrease concentrations of air contaminants. It focuses on indoor air quality in both single and multifamily energy-efficient residences. Information about commercial structures such as hospitals and office buildings is presented when it also applies to residences. Basic concepts of contaminants and their concentrations, sources and removal mechanisms, contaminant distribution, heat transfer, and air exchange are discussed. The effects of the building system on indoor air quality are examined. The effects of the external environment, building envelope, environmental control systems, interior design, furnishings, and inhabitants on the emission, dispersion, and removal of indoor air contaminants as well as direct and indirect effects of energy-efficient features are discussed. The health effects of specific air contaminants and the health standards developed for them are examined. Available methods for predicting and measuring contaminants and for evaluating human responses are discussed. Methods and equipment available for the control of indoor air pollution once the contaminants have been identified are also evaluated. The potential legal aspects, including regulatory intervention and civil lawsuits, of failure to evaluate and control indoor air pollution are discussed. A list of references, a glossary, and an index are also included

Saving energy via high-efficiency fans.

Science.gov (United States)

Heine, Thomas

2016-08-01

Thomas Heine, sales and market manager for EC Upgrades, the retrofit arm of global provider of air movement solutions, ebm-papst A&NZ, discusses the retrofitting of high-efficiency fans to existing HVAC equipment to 'drastically reduce energy consumption'.

Solutions for Energy Efficient and Sustainable Heating of Ventilation Air: A Review

Directory of Open Access Journals (Sweden)

A. Žandeckis

2015-10-01

Full Text Available A high energy efficiency and sustainability standards defined by modern society and legislation requires solutions in the form of complex integrated systems. The scope of this work is to provide a review on technologies and methods for the heating of ventilation air as a key aspect for high energy and environmental performance of buildings located in a cold climate. The results of this work are more relevant in the buildings where space heating consumes a significant part of the energy balance of a building, and air exchange is arranged in an organized manner. A proper design and control strategy, heat recovery, the use of renewable energy sources, and waste heat are the main aspects which must be considered for efficient and sustainable ventilation. This work focuses on these aspects. Air conditioning is not in the scope of this study.

High surface area carbon for bifunctional air electrodes applied in zinc-air batteries

Energy Technology Data Exchange (ETDEWEB)

Arai, H [on leave from NTT Laboratories (Japan); Mueller, S; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Bifunctional air electrodes with high surface area carbon substrates showed low reduction overpotential, thus are promising for enhancing the energy efficiency and power capability of zinc-air batteries. The improved performance is attributed to lower overpotential due to diffusion of the reaction intermediate, namely the peroxide ion. (author) 1 fig., 2 refs.

Experiments on high efficiency aerosol filtration

International Nuclear Information System (INIS)

Mazzini, M.; Cuccuru, A.; Kunz, P.

1977-01-01

Research on high efficiency aerosol filtration by the Nuclear Engineering Institute of Pisa University and by CAMEN in collaboration with CNEN is outlined. HEPA filter efficiency was studied as a function of the type and size of the test aerosol, and as a function of flowrate (+-50% of the nominal value), air temperature (up to 70 0 C), relative humidity (up to 100%), and durability in a corrosive atmosphere (up to 140 hours in NaCl mist). In the selected experimental conditions these influences were appreciable but are not sufficient to be significant in industrial HEPA filter applications. Planned future research is outlined: measurement of the efficiency of two HEPA filters in series using a fixed particle size; dependence of the efficiency on air, temperatures up to 300-500 0 C; performance when subject to smoke from burning organic materials (natural rubber, neoprene, miscellaneous plastics). Such studies are relevant to possible accidental fires in a plutonium laboratory

Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

International Nuclear Information System (INIS)

Schilling, J.B.

1997-09-01

Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction

A Controlled Design of Ripple-Like Polyamide-6 Nanofiber/Nets Membrane for High-Efficiency Air Filter.

Science.gov (United States)

Zhang, Shichao; Liu, Hui; Zuo, Fenglei; Yin, Xia; Yu, Jianyong; Ding, Bin

2017-03-01

The filtration capacity of fibrous media for airborne particles is restricted by their thick diameter, low porosity, and limited frontal area. The ability to solve this problem would have broad technological implications for various air filtration applications; despite many past efforts, it remains a great challenge to achieve. Herein, a facile and scalable strategy to fabricate the ripple-like polyamide-6 nanofiber/nets (PA-6 NF/N) air filter via combining electrospinning/netting technique with receiving substrate design is demonstrated. This proposed approach allows the scaffold filaments to orderly embed into 2D PA-6 nanonets layer with Steiner-tree structures and nanoscale diameter of ≈20 nm, resulting in the ripple-like membrane with extremely small pore size, highly porous structure, and hugely extended frontal surface, by facilely adjusting its pleat span and pleat pitch. These unique structural advantages enable the ripple-like PA-6 NF/N filter to filtrate the ultrafine particles with high removal efficiency of 99.996%, low air resistance of 95 Pa, and robust quality factor of >0.11 Pa -1 ; using its superlight weight of 0.9 g m -2 and physical sieving manner. This approach has the potentialities to give rise to a novel generation of filter media displaying enhanced filtration capacity for various applications thanks to their nanoscale features and designed macrostructures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrical efficiency losses occurred by the air compressor for PEMFC

International Nuclear Information System (INIS)

Haubrock, J.; Heideck, G.; Styczynski, Z.

2006-01-01

Fuel Cells are characterised by a high efficiency and comparatively small emissions. Depending on their partial load behaviour and their high efficiency, Fuel Cells are well suited for net connected or isolated autonomous energy generators for thermal and electricity power production. Proton Exchange Membrane (PEM) Fuel Cell systems need several external components to produce electricity and thermal power. However, the high theoretical degree of efficiency of 83% is decreased by these components. To reach higher fuel utilisation it is necessary to reduce the energy consumption of these components. In this study, the influence of the air supply compressor on the fuel utilisation is investigated and an optimization strategy was developed. The results were reviewed by a real test set up using an autonomous PEM Fuel Cell system. (authors)

LDDX: A High Efficiency Air Conditioner for DOD Buildings

Science.gov (United States)

2017-02-01

Additional Benefits ........................................................................................................ 3 1.2.6 Deliverables...inadequate latent cooling can lead building managers to restrict ventilation to minimal levels that further compromise both the comfort and health of...bulb temperatures for outdoor air and return air respectively per ANSI/AHRI Standard 210/240 “Performance Rating of Unitary Air-Conditioning and Air

Stabilization void-fill encapsulation high-efficiency particulate filters

International Nuclear Information System (INIS)

Alexander, R.G.; Stewart, W.E.; Phillips, S.J.; Serkowski, M.M.; England, J.L.; Boynton, H.C.

1994-05-01

This report discusses high-efficiency particulate air (HEPA) filter systems that which are contaminated with radionuclides are part of the nuclear fuel processing systems conducted by the US Department of Energy (DOE) and require replacement and safe and efficient disposal for plant safety. Two K-3 HEPA filters were removed from service, placed burial boxes, buried, and safely and efficiently stabilized remotely which reduced radiation exposure to personnel and the environment

Health and efficiency in trimix versus air breathing in compressed air workers

NARCIS (Netherlands)

van Rees Vellinga, T. P.; Verhoeven, A. C.; van Dijk, F. J. H.; Sterk, W.

2006-01-01

The Western Scheldt Tunneling Project in the Netherlands provided a unique opportunity to evaluate the effects of trimix usage on the health of compressed air workers and the efficiency of the project. Data analysis addressed 318 exposures to compressed air at 3.9-4.4 bar gauge and 52 exposures to

High quality ceramic coatings sprayed by high efficiency hypersonic plasma spraying gun

International Nuclear Information System (INIS)

Zhu Sheng; Xu Binshi; Yao JiuKun

2005-01-01

This paper introduced the structure of the high efficiency hypersonic plasma spraying gun and the effects of hypersonic plasma jet on the sprayed particles. The optimised spraying process parameters for several ceramic powders such as Al 2 O 3 , Cr 2 O 3 , ZrO 2 , Cr 3 C 2 and Co-WC were listed. The properties and microstructure of the sprayed ceramic coatings were investigated. Nano Al 2 O 3 -TiO 2 ceramic coating sprayed by using the high efficiency hypersonic plasma spraying was also studied. Compared with the conventional air plasma spraying, high efficiency hypersonic plasma spraying improves greatly the ceramic coatings quality but at low cost. (orig.)

Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

Science.gov (United States)

Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

2008-11-01

High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

High-Performance Carbon Aerogel Air Cathodes for Microbial Fuel Cells

KAUST Repository

Zhang, Xiaoyuan

2016-08-11

Microbial fuel cells (MFCs) can generate electricity from the oxidation of organic substrates using anodic exoelectrogenic bacteria and have great potential for harvesting electric energy from wastewater. Improving oxygen reduction reaction (ORR) performance at a neutral pH is needed for efficient energy production. Here we show a nitrogen doped (≈4 wt%) ionothermal carbon aerogel (NDC) with a high surface area, large pore volume, and hierarchical porosity, with good electrocatalytic properties for ORR in MFCs. The MFCs using NDC air cathodes achieved a high maximum power density of 2300 mW m−2, which was 1.7 times higher than the most commonly used Pt/C air cathodes and also higher than most state-of-the-art ORR catalyst air cathodes. Rotating disk electrode measurements verified the superior electrocatalytic activity of NDC with an efficient four-electron transfer pathway (n=3.9). These findings highlight NDC as a better-performing and cost-efficient catalyst compared with Pt/C, making it highly viable for MFC applications.

Facile and Scalable Fabrication of Highly Efficient Lead Iodide Perovskite Thin-Film Solar Cells in Air Using Gas Pump Method.

Science.gov (United States)

Ding, Bin; Gao, Lili; Liang, Lusheng; Chu, Qianqian; Song, Xiaoxuan; Li, Yan; Yang, Guanjun; Fan, Bin; Wang, Mingkui; Li, Chengxin; Li, Changjiu

2016-08-10

Control of the perovskite film formation process to produce high-quality organic-inorganic metal halide perovskite thin films with uniform morphology, high surface coverage, and minimum pinholes is of great importance to highly efficient solar cells. Herein, we report on large-area light-absorbing perovskite films fabrication with a new facile and scalable gas pump method. By decreasing the total pressure in the evaporation environment, the gas pump method can significantly enhance the solvent evaporation rate by 8 times faster and thereby produce an extremely dense, uniform, and full-coverage perovskite thin film. The resulting planar perovskite solar cells can achieve an impressive power conversion efficiency up to 19.00% with an average efficiency of 17.38 ± 0.70% for 32 devices with an area of 5 × 2 mm, 13.91% for devices with a large area up to 1.13 cm(2). The perovskite films can be easily fabricated in air conditions with a relative humidity of 45-55%, which definitely has a promising prospect in industrial application of large-area perovskite solar panels.

High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor

KAUST Repository

Holliday, Sarah

2016-06-09

Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which themselves have issues with cost, stability and limited spectral absorption. Here we present a new non-fullerene acceptor that has been specifically designed to give improved performance alongside the wide bandgap donor poly(3-hexylthiophene), a polymer with significantly better prospects for commercial OPV due to its relative scalability and stability. Thanks to the well-matched optoelectronic and morphological properties of these materials, efficiencies of 6.4% are achieved which is the highest reported for fullerene-free P3HT devices. In addition, dramatically improved air stability is demonstrated relative to other high-efficiency OPV, showing the excellent potential of this new material combination for future technological applications.

High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor

Science.gov (United States)

Holliday, Sarah; Ashraf, Raja Shahid; Wadsworth, Andrew; Baran, Derya; Yousaf, Syeda Amber; Nielsen, Christian B.; Tan, Ching-Hong; Dimitrov, Stoichko D.; Shang, Zhengrong; Gasparini, Nicola; Alamoudi, Maha; Laquai, Frédéric; Brabec, Christoph J.; Salleo, Alberto; Durrant, James R.; McCulloch, Iain

2016-01-01

Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which themselves have issues with cost, stability and limited spectral absorption. Here we present a new non-fullerene acceptor that has been specifically designed to give improved performance alongside the wide bandgap donor poly(3-hexylthiophene), a polymer with significantly better prospects for commercial OPV due to its relative scalability and stability. Thanks to the well-matched optoelectronic and morphological properties of these materials, efficiencies of 6.4% are achieved which is the highest reported for fullerene-free P3HT devices. In addition, dramatically improved air stability is demonstrated relative to other high-efficiency OPV, showing the excellent potential of this new material combination for future technological applications. PMID:27279376

High-efficiency and air-stable P3HT-based polymer solar cells with a new non-fullerene acceptor

KAUST Repository

Holliday, Sarah; Ashraf, Raja Shahid; Wadsworth, Andrew; Baran, Derya; Yousaf, Syeda Amber; Nielsen, Christian B.; Tan, Ching-Hong; Dimitrov, Stoichko D.; Shang, Zhengrong; Gasparini, Nicola; Alamoudi, Maha; Laquai, Fré dé ric; Brabec, Christoph J.; Salleo, Alberto; Durrant, James R.; McCulloch, Iain

2016-01-01

Solution-processed organic photovoltaics (OPV) offer the attractive prospect of low-cost, light-weight and environmentally benign solar energy production. The highest efficiency OPV at present use low-bandgap donor polymers, many of which suffer from problems with stability and synthetic scalability. They also rely on fullerene-based acceptors, which themselves have issues with cost, stability and limited spectral absorption. Here we present a new non-fullerene acceptor that has been specifically designed to give improved performance alongside the wide bandgap donor poly(3-hexylthiophene), a polymer with significantly better prospects for commercial OPV due to its relative scalability and stability. Thanks to the well-matched optoelectronic and morphological properties of these materials, efficiencies of 6.4% are achieved which is the highest reported for fullerene-free P3HT devices. In addition, dramatically improved air stability is demonstrated relative to other high-efficiency OPV, showing the excellent potential of this new material combination for future technological applications.

High efficiency particulate air filter technology from 1980 to 1985 in the Central Electricity Generating Board

International Nuclear Information System (INIS)

Skledon, R.; Taylor, S.; Fern, C.; Stead, M.

1986-01-01

This paper examines at the Central Electricity Generating Board's methods of High Efficiency Particulate Air (1,700 m 3 /hr) filter testing from conception to the present day. The choice of the test and the early results are looked at followed by the development using new test equipment for checking ladderframe systems. The need for the drawing up of the Central Electricity Generating Board 743401 Standard for filter manufacture and its effect on full implementation is looked into. The advantages and disadvantages of our test procedures are reflected upon and the future developments in test methods and filters for use by the C.E.G.B. in their power stations are discussed. (author)

High efficiency mixed species radioiodine air sampling, readout, and dose assessment system

International Nuclear Information System (INIS)

Distenfeld, C.; Klemish, J.

1976-05-01

Reactor accidents require monitoring to assess the impact to persons in the environment. This implies methods and apparatus to accurately and economically sample and evaluate possible released activity. The development of a prototype iodine air sampling system that can differentiate against noble gas activity and be evaluated by standard Civil Defense instrumentation is reported. The apparatus can efficiently (95 percent) collect organic or inorganic, particulate or gaseous radioiodine in concentrations below stable atmospheric iodine, and under severe ambient conditions. Response to noble fission gases was reduced to less than 4 x 10 -4 of an equal iodine airborne activity by heating the collector to approximately 100 0 C. Reliable sample size, +-5 percent, was achieved by using a simple air flow regulator. Thyroid dose commitment was mathematically and graphically related to the iodine isotope distribution expected in the environment and to the response of the Civil Defense CDV-700 instrument used to evaluate the sample. Sensitivity of the method allows dose assessment of 1 to 2 rads to a child's thyroid

An efficient mathematical model for air-breathing PEM fuel cells

International Nuclear Information System (INIS)

Ismail, M.S.; Ingham, D.B.; Hughes, K.J.; Ma, L.; Pourkashanian, M.

2014-01-01

Graphical abstract: The effects of the ambient humidity on the performance of air-breathing PEM fuel cells become more pronounced as the ambient temperature increases. The polarisation curves have been generated using the in-house developed MATLAB® application, Polarisation Curve Generator, which is available in the supplementary data. - Highlights: • An efficient mathematical model has been developed for an air-breathing PEM fuel cell. • The fuel cell performance is significantly over-predicted if the Joule and entropic heats are neglected. • The fuel cell performance is highly sensitive to the state of water at the thermodynamic equilibrium. • The cell potential dictates the favourable ambient conditions for the fuel cell. - Abstract: A simple and efficient mathematical model for air-breathing proton exchange membrane (PEM) fuel cells has been built. One of the major objectives of this study is to investigate the effects of the Joule and entropic heat sources, which are often neglected, on the performance of air-breathing PEM fuel cells. It is found that the fuel cell performance is significantly over-predicted if one or both of these heat sources is not incorporated into the model. Also, it is found that the performance of the fuel cell is highly sensitive to the state of the water at the thermodynamic equilibrium magnitude as both the entropic heat and the Nernst potential considerably increase if water is assumed to be produced in liquid form rather than in vapour form. Further, the heat of condensation is shown to be small and therefore, under single-phase modelling, has a negligible effect on the performance of the fuel cell. Finally, the favourable ambient conditions depend on the operating cell potential. At intermediate cell potentials, a mild ambient temperature and low humidity are favoured to maintain high membrane conductivity and mitigate water flooding. At low cell potentials, low ambient temperature and high humidity are favoured to

Residential air-conditioner usage in China and efficiency standardization

International Nuclear Information System (INIS)

Wu, Jianghong; Liu, Chaopeng; Li, Hongqi; Ouyang, Dong; Cheng, Jianhong; Wang, Yuanxia; You, Shaofang

2017-01-01

Determining the real energy consumption and usage pattern of a room air-conditioner (RAC) are important issues from the point of view of both RAC design and evaluation of its energy efficiency. An air-conditioner's running time is fundamental data for the calculation of SEER and APF values. Therefore, in 2010, a nationwide investigation of RAC usage was conducted and 400 selected air-conditioning-units were monitored for a full year to obtain data on their cooling and heating usage. Two running time curves (cooling and heating) were obtained for the air-conditioners as a function of outdoor air temperatures using statistical analysis. The results show that the 27–30 °C temperature range accounts for more than 52% of the cooling time. Conversely, the 0–8 °C temperature range is associated with more than 75% of the heating time. The research presented in this paper has significantly contributed to China's new variable-speed RAC efficiency standard (GB21455-2013). It also has far-reaching implications for both the air-conditioner industry and energy policy in China due to its different method of calculating energy efficiency. - Highlights: • A nationwide survey to realize China's residential air-conditions usage behaviors. • Air-conditioner running time-environment temperature curves are obtained. • The peak heating demand and peak cooling demand happen at 28 °C and 4 °C, respectively. • The temperature of 27 °C–30 °C accounts for over 52% refrigeration time. • The temperature of 0 °C–8 °C occupies more than 75% heating time.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

OpenAIRE

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle cl...

Investigation of efficiency of air cleaning from acetone using a segmental construction biofilter

Directory of Open Access Journals (Sweden)

Denas Bacevičius

2015-10-01

Full Text Available Volatile organic compounds, e. g. acetone, have a direct impact on climate change, decrease of ozone in the air, and on the growth of greenhouse effect. One of the most popular air purifying methods from VOC is a biological air cleaning. Experimental investigations were conducted to determine the efficiency of the new structure of biofilter with polypropylene plates segments. During the investigations the efficiency of segmental construction biofilter of air purification at different initial concentrations of pollutants was determined. Different concentrations of pollutants were estimated during the acetone dilution with water. During the tests the efficiency of biofilter air purification from acetone vapor and its change under different concentrations of vapors was set. Based on test results, the maximum efficiency of biofilter air purification was up to 93%. Studies have shown that increasing the allowable pollutant concentration, the efficiency of air purification unit decreases. Increasing the concentration of supplied acetone vapor into the biofilter from 232 to 701 mg/m3, cleaning efficiency decreased from 92.8 to 82.3%. Since microorganisms fail to oxidize organic compounds, the filter works better at lower initial concentrations of pollutants.

Preliminary field evaluation of high efficiency steel filters

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Larsen, G.; Lopez, R. [Lawrence Livermore National Laboratory, CA (United States)] [and others

1995-02-01

We have conducted an evaluation of two high efficiency steel filters in the exhaust of an uranium oxide grit blaster at the Y-12 Plant in Oak Ridge Tennessee. The filters were installed in a specially designed filter housing with a reverse air-pulse cleaning system for automatically cleaning the filters in-place. Previous tests conducted on the same filters and housing at LLNL under controlled conditions using Arizona road dust showed good cleanability with reverse air pulses. Two high efficiency steel filters, containing 64 pleated cartridge elements housed in the standard 2` x 2` x 1` HEPA frame, were evaluated in the filter test housing using a 1,000 cfm slip stream containing a high concentration of depleted uranium oxide dust. One filter had the pleated cartridges manufactured to our specifications by the Pall Corporation and the other by Memtec Corporation. Test results showed both filters had a rapid increase in pressure drop with time, and reverse air pulses could not decrease the pressure drop. We suspected moisture accumulation in the filters was the problem since there were heavy rains during the evaluations, and the pressure drop of the Memtec filter decreased dramatically after passing clean, dry air through the filter and after the filter sat idle for one week. Subsequent laboratory tests on a single filter cartridge confirmed that water accumulation in the filter was responsible for the increase in filter pressure drop and the inability to lower the pressure drop by reverse air pulses. No effort was made to identify the source of the water accumulation and correct the problem because the available funds were exhausted.

Efficient air pollution abatement for regions in China

Energy Technology Data Exchange (ETDEWEB)

Hu, J.L. [National Chiao Tung University, Taipei (Taiwan). Inst. for Business & Management

2006-08-15

This paper computes the efficient air pollution abatement ratios of 30 regions in China during the period 1996-2002. Three air emissions (SO{sub 2}, soot and dust) are considered. Data envelopment analysis (DEA) with a single output (real GDP) and five inputs (labour, real capital stock, SO{sub 2}, dust and soot emissions) is used to compute the target emissions of each region for each year. The efficient abatement ratios of each region in each year are then obtained by dividing the target emission by the actual emission of an air pollutant. Our major findings are: 1. The eastern area is the most efficient region with respect to SO{sub 2}, soot and dust emissions in every year during the research period. 2. The eastern, central and western areas have the lowest, medium and highest 1996-2002 average target abatement ratios of SO, (22.09%, 42.23% and 57.58%), soot (26.19%, 56.34% and 66.37%) and dust (15.20%, 29.09% and 40.59%), respectively. 3. These results are consistent with the Environmental Kuznets Curve (EKC) theory, whereby a more developed area will use environmental goods more efficiently than a less developed area. 4. Compared to dust emission, the average target abatement ratios for SO{sub 2} and soot emissions (as direct outcomes of burning coal) are relatively much higher for all three areas.

Effects of air jet duration and timing on the combustion characteristics of high-pressure air jet controlled compression ignition combustion mode in a hybrid pneumatic engine

International Nuclear Information System (INIS)

Long, Wuqiang; Meng, Xiangyu; Tian, Jiangping; Tian, Hua; Cui, Jingchen; Feng, Liyan

2016-01-01

Highlights: • A 3-D CFD model of the power cylinder in HPE was developed. • High-pressure air JCCI combustion mode includes two-stage high-temperature reaction. • The combustion phasing of the pre-mixture is controllable via the SOJ timing. • There exists an optimum SOJ timing for obtaining the highest combustion efficiency and shortest burning duration. - Abstract: The high-pressure air jet controlled compression ignition (JCCI) combustion mode was employed to control the premixed diesel compression ignition combustion phasing by using the compound thermodynamic cycle under all operating conditions, which is accomplished in a hybrid pneumatic engine (HPE). A three-dimensional computational fluid dynamics (CFD) numerical simulation coupled with reduced n-heptane chemical kinetics mechanism has been applied to investigate the effects of high-pressure air jet duration and the start of jet (SOJ) timing on the combustion characteristics in the power cylinder of HPE. By sweeping the high-pressure air jet durations from 6 to 14 °CA and SOJ timings from −12 °CA ATDC to the top dead center (TDC) under the air jet temperatures of 400 and 500 K, respectively, the low- and high-temperature reactions, combustion efficiency, as well as the combustion phasing and burning duration have been analyzed in detail. The results illustrated that a longer air jet duration results in a higher peak in the first-stage high-temperature reaction, and the short air jet duration of 6 °CA can lead to a higher combustion efficiency. The SOJ timing sweep results showed that there exists an optimum timing for obtaining the highest combustion efficiency and shortest burning duration.

High-throughput liquid-absorption air-sampling apparatus and methods

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-11

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is < 10 cm of water, usually < 5 cm of water. The sampler's collection efficiency is usually > 20% for vapors or airborne particulates in the 2--3 microns range and > 50% for particles larger than 4 microns. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

Chapter 22: Compressed Air Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

Energy Technology Data Exchange (ETDEWEB)

Kurnik, Charles W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Benton, Nathanael [Nexant, Inc., San Francisco, CA (United States); Burns, Patrick [Nexant, Inc., San Francisco, CA (United States)

2017-10-18

Compressed-air systems are used widely throughout industry for many operations, including pneumatic tools, packaging and automation equipment, conveyors, and other industrial process operations. Compressed-air systems are defined as a group of subsystems composed of air compressors, air treatment equipment, controls, piping, pneumatic tools, pneumatically powered machinery, and process applications using compressed air. A compressed-air system has three primary functional subsystems: supply, distribution, and demand. Air compressors are the primary energy consumers in a compressed-air system and are the primary focus of this protocol. The two compressed-air energy efficiency measures specifically addressed in this protocol are: High-efficiency/variable speed drive (VSD) compressor replacing modulating, load/unload, or constant-speed compressor; and Compressed-air leak survey and repairs. This protocol provides direction on how to reliably verify savings from these two measures using a consistent approach for each.

Aerodynamic Efficiency Enhancements for Air Vehicles, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The need for aerodynamics-based efficiency enhancements for air vehicles is presented. Concepts are presented for morphing aircraft, to enable the aircraft to...

Aerodynamic Efficiency Enhancements for Air Vehicles, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The need for aerodynamics-based efficiency enhancements for air vehicles is presented. The results of the Phase I investigation of concepts for morphing aircraft are...

High-efficiency pumps drastically reduce energy consumption

Energy Technology Data Exchange (ETDEWEB)

Anon

2002-05-01

Wilo's Stratos pumps for air conditioning and other domestic heating applications combine the advantages of wet runner technology with an innovative electronic commutator motor. The energy consumption of these high-efficiency pumps is halved compared with similar wet runner designs. With vast numbers of pumps used in buildings across Europe alone, the adoption of this technology potentially offers significant energy sayings. (Author)

Effect of air flow on tubular solar still efficiency.

Science.gov (United States)

Thirugnanasambantham, Arunkumar; Rajan, Jayaprakash; Ahsan, Amimul; Kandasamy, Vinothkumar

2013-01-01

An experimental work was reported to estimate the increase in distillate yield for a compound parabolic concentrator-concentric tubular solar still (CPC-CTSS). The CPC dramatically increases the heating of the saline water. A novel idea was proposed to study the characteristic features of CPC for desalination to produce a large quantity of distillate yield. A rectangular basin of dimension 2 m × 0.025 m × 0.02 m was fabricated of copper and was placed at the focus of the CPC. This basin is covered by two cylindrical glass tubes of length 2 m with two different diameters of 0.02 m and 0.03 m. The experimental study was operated with two modes: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively. THE EXPERIMENTAL STUDY WAS OPERATED WITH TWO MODES: without and with air flow between inner and outer tubes. The rate of air flow was fixed throughout the experiment at 4.5 m/s. On the basis of performance results, the water collection rate was 1445 ml/day without air flow and 2020 ml/day with air flow and the efficiencies were 16.2% and 18.9%, respectively.

Discussion on Boiler Efficiency Correction Method with Low Temperature Economizer-Air Heater System

Science.gov (United States)

Ke, Liu; Xing-sen, Yang; Fan-jun, Hou; Zhi-hong, Hu

2017-05-01

This paper pointed out that it is wrong to take the outlet flue gas temperature of low temperature economizer as exhaust gas temperature in boiler efficiency calculation based on GB10184-1988. What’s more, this paper proposed a new correction method, which decomposed low temperature economizer-air heater system into two hypothetical parts of air preheater and pre condensed water heater and take the outlet equivalent gas temperature of air preheater as exhaust gas temperature in boiler efficiency calculation. This method makes the boiler efficiency calculation more concise, with no air heater correction. It has a positive reference value to deal with this kind of problem correctly.

EER, COP, and the Second Law Efficiency for Air Conditioners

Science.gov (United States)

Leff, Harvey S.; Teeters, William D.

1978-01-01

Describes the relationship existing between coefficient of performance (COP) and energy efficiency ratio (EER) in air conditioning units and introduces new efficiency parameters measured relative to the energy extracted from the primary energy source. (SL)

Cooling energy efficiency and classroom air environment of a school building operated by the heat recovery air conditioning unit

International Nuclear Information System (INIS)

Wang, Yang; Zhao, Fu-Yun; Kuckelkorn, Jens; Liu, Di; Liu, Li-Qun; Pan, Xiao-Chuan

2014-01-01

The recently-built school buildings have adopted novel heat recovery ventilator and air conditioning system. Heat recovery efficiency of the heat recovery facility and energy conservation ratio of the air conditioning unit were analytically modeled, taking the ventilation networks into account. Following that, school classroom displacement ventilation and its thermal stratification and indoor air quality indicated by the CO 2 concentration have been numerically modeled concerning the effects of delivering ventilation flow rate and supplying air temperature. Numerical results indicate that the promotion of mechanical ventilation rate can simultaneously boost the dilution of indoor air pollutants and the non-uniformity of indoor thermal and pollutant distributions. Subsequent energy performance analysis demonstrates that classroom energy demands for ventilation and cooling could be reduced with the promotion of heat recovery efficiency of the ventilation facility, and the energy conservation ratio of the air conditioning unit decreases with the increasing temperatures of supplying air. Fitting correlations of heat recovery ventilation and cooling energy conservation have been presented. - Highlights: • Low energy school buildings and classroom environment. • Heat recovery facility operating with an air conditioning unit. • Displacement ventilation influenced by the heat recovery efficiency. • Energy conservation of cooling and ventilation through heat recovery. • Enhancement of classroom environment with reduction of school building energy

Health and efficiency in trimix versus air breathing in compressed air workers.

Science.gov (United States)

Van Rees Vellinga, T P; Verhoeven, A C; Van Dijk, F J H; Sterk, W

2006-01-01

The Western Scheldt Tunneling Project in the Netherlands provided a unique opportunity to evaluate the effects of trimix usage on the health of compressed air workers and the efficiency of the project. Data analysis addressed 318 exposures to compressed air at 3.9-4.4 bar gauge and 52 exposures to trimix (25% oxygen, 25% helium, and 50% nitrogen) at 4.6-4.8 bar gauge. Results revealed three incidents of decompression sickness all of which involved the use of compressed air. During exposure to compressed air, the effects of nitrogen narcosis were manifested in operational errors and increased fatigue among the workers. When using trimix, less effort was required for breathing, and mandatory decompression times for stays of a specific duration and maximum depth were considerably shorter. We conclude that it might be rational--for both medical and operational reasons--to use breathing gases with lower nitrogen fractions (e.g., trimix) for deep-caisson work at pressures exceeding 3 bar gauge, although definitive studies are needed.

Viewpoint Mitigation of emissions through energy efficiency standards for room air conditioners in Malaysia

International Nuclear Information System (INIS)

Mahlia, T.M.I.; Masjuki, H.H.; Saidur, R.; Amalina, M.A.

2004-01-01

Malaysian economy has grown rapidly in the last two decades. This growth has increased the ownership of household electrical appliances including room air conditioners. The number of users of air conditioners is predicted to grow dramatically in Malaysian households in the future. To reduce energy consumption in the residential sector, the Malaysia Energy Commission is considering implementing minimum energy efficiency standards for room air conditioners in early 2004. This paper attempts to predict the potential mitigation of emissions through energy efficiency standards for room air conditioners in Malaysia. The calculations were based on the growth of room air conditioners ownership data in Malaysian households. The study found that the energy efficiency standards for room air conditioners would mitigate a significant amount of emissions in this country

New, Efficient, and Reliable Air Electrode Material for Proton-Conducting Reversible Solid Oxide Cells.

Science.gov (United States)

Huan, Daoming; Shi, Nai; Zhang, Lu; Tan, Wenzhou; Xie, Yun; Wang, Wanhua; Xia, Changrong; Peng, Ranran; Lu, Yalin

2018-01-17

Driven by the demand to minimize fluctuation in common renewable energies, reversible solid oxide cells (RSOCs) have drawn increasing attention for they can operate either as fuel cells to produce electricity or as electrolysis cells to store electricity. Unfortunately, development of proton-conducting RSOCs (P-RSOCs) faces a major challenge of poor reliability because of the high content of steam involved in air electrode reactions, which could seriously decay the lifetime of air electrode materials. In this work, a very stable and efficient air electrode, SrEu 2 Fe 1.8 Co 0.2 O 7-δ (SEFC) with layer structure, is designed and deployed in P-RSOCs. X-ray diffraction analysis and High-angle annular dark-filed scanning transmission electron microscopy images of SEFC reveal that Sr atoms occupy the center of perovskite slabs, whereas Eu atoms arrange orderly in the rock-salt layer. Such a special structure of SEFC largely depresses its Lewis basicity and therefore its reactivity with steam. Applying the SEFC air electrode, our button switches smoothly between both fuel cell and electrolysis cell (EC) modes with no obvious degradation over a 135 h long-term test under wet H 2 (∼3% H 2 O) and 10% H 2 O-air atmospheres. A record of over 230 h is achieved in the long-term stability test in the EC mode, doubling the longest test that had been previously reported. Besides good stability, SEFC demonstrates great catalytic activity toward air electrode reactions when compared with traditional La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ air electrodes. This research highlights the potential of stable and efficient P-RSOCs as an important part in a sustainable new energy power system.

Experimental analysis of fuzzy controlled energy efficient demand controlled ventilation economizer cycle variable air volume air conditioning system

Directory of Open Access Journals (Sweden)

Rajagopalan Parameshwaran

2008-01-01

Full Text Available In the quest for energy conservative building design, there is now a great opportunity for a flexible and sophisticated air conditioning system capable of addressing better thermal comfort, indoor air quality, and energy efficiency, that are strongly desired. The variable refrigerant volume air conditioning system provides considerable energy savings, cost effectiveness and reduced space requirements. Applications of intelligent control like fuzzy logic controller, especially adapted to variable air volume air conditioning systems, have drawn more interest in recent years than classical control systems. An experimental analysis was performed to investigate the inherent operational characteristics of the combined variable refrigerant volume and variable air volume air conditioning systems under fixed ventilation, demand controlled ventilation, and combined demand controlled ventilation and economizer cycle techniques for two seasonal conditions. The test results of the variable refrigerant volume and variable air volume air conditioning system for each techniques are presented. The test results infer that the system controlled by fuzzy logic methodology and operated under the CO2 based mechanical ventilation scheme, effectively yields 37% and 56% per day of average energy-saving in summer and winter conditions, respectively. Based on the experimental results, the fuzzy based combined system can be considered to be an alternative energy efficient air conditioning scheme, having significant energy-saving potential compared to the conventional constant air volume air conditioning system.

Efficiency enhancement in IGCC power plants with air-blown gasification and hot gas clean-up

International Nuclear Information System (INIS)

Giuffrida, Antonio; Romano, Matteo C.; Lozza, Giovanni

2013-01-01

Air-blown IGCC systems with hot fuel gas clean-up are investigated. In detail, the gas clean-up station consists of two reactors: in the first, the raw syngas exiting the gasifier and passed through high-temperature syngas coolers is desulfurized by means of a zinc oxide-based sorbent, whereas in the second the sulfided sorbent is duly regenerated. The hot fuel gas clean-up station releases H 2 S-free syngas, which is ready to fuel the combustion turbine after hot gas filtration, and a SO 2 -laden stream, which is successively treated in a wet scrubber. A thermodynamic analysis of two air-blown IGCC systems, the first with cold fuel gas clean-up and the second with hot fuel gas clean-up, both with a state-of-the-art combustion turbine as topping cycle, shows that it is possible to obtain a really attractive net efficiency (more than 51%) for the second system, with significant improvements in comparison with the first system. Nevertheless, higher efficiency is accomplished with a small reduction in the power output and no sensible efficiency improvements seem to be appreciated when the desulfurization temperature increases. Other IGCC systems, with an advanced 1500 °C-class combustion turbine as the result of technology improvements, are investigated as well, with efficiency as high as 53%. - Highlights: ► Hot fuel gas clean-up is a highly favorable technology for IGCC concepts. ► Significant IGCC efficiency improvements are possible with hot fuel gas clean-up. ► Size reductions of several IGCC components are possible. ► Higher desulfurization temperatures do not sensibly affect IGCC efficiency. ► IGCC efficiency as high as 53% is possible with a 1500°C-class combustion turbine

Movable air solar collector and its efficiency

International Nuclear Information System (INIS)

Lauva, A.; Aboltinš, A.; Palabinskis, J.; Karpova Sadigova, N.

2008-01-01

Implementing the guidelines of the Latvian National Programme for Energy in the field of alternative energy, intensive research shall be carried on regarding the use of solar energy, as it can be successfully used not only for the purposes of water heating and production of electrical energy, but also for air warming. The amount of heat necessary for the drying of rough forage and grain drying by active aeration in June, July and August can be obtained using solar radiation. The Latvian Guidelines for the Energy Development 2006-2016 state that the solar radiance in Latvia is of quite low intensity. The total amount of solar energy is 1109 kWh m -2 per year. The period of usage of the solar thermal energy is beginning from the last decade of April, when the intensity of radiation is 120 kWh m -2 , until the first decade of September. Within this period (approximately 1800 hours), it is possible to use the solar thermal energy by placing solar collectors. The usage of solar collectors for in drying of agricultural production is topical from the viewpoint of decreasing the consumption of energy used for the drying, as electrical energy and fossil energy resources become more expensive and tend to run out. In the processes that concern drying of agricultural production, efficiently enough solar radiation energy can be used. Due to this reason researching continues and expands in the field of usage of solar energy for the processes of drying and heating. The efficiency factor of the existing solar collectors is not high, but they are of simple design and cheep for production and exploitation. By improving the design of the solar collectors and choosing modern materials that absorb the solar radiation energy, it is possible the decrease the efficiency factor of solar collectors and decrease the production costs. In the scientific laboratory of grain drying and storage of Latvia University of Agriculture, a pilot device movable folding solar collector pilot device

Available online Efficiency potential of indirectly heated solar reforming with different types of solar air receivers

International Nuclear Information System (INIS)

Storch, Henrik von; Roeb, Martin; Stadler, Hannes; Sattler, Christian; Hoffschmidt, Bernhard

2016-01-01

Highlights: • A process for indirectly heated solar reforming of natural gas with air as heat transfer fluid is proposed. • Different solar receivers are modeled and implemented into the reforming process. • The overall efficiency of the process with different solar receivers is determined. • Optimum solar receiver characteristics for application in a solar reforming process are determined. - Abstract: In solar reforming, the heating value of natural gas is increased by utilization of concentrated solar radiation. Hence, it is a process for storing solar energy in a stable and transportable form that also permits further conversion into liquid fuels like methanol. This process has the potential to significantly decrease the natural gas consumption and the associated CO_2-emissions of methanol production with only few open questions to be addressed prior to commercialization. In the medium and long term, it has the potential to generate methanol as an environmentally friendly fuel for both transport as well as flexible electricity production in combined cycle gas turbines, when biogas is used as reactant. In a previous study the high potential of indirectly heated solar reforming with solar air receivers was shown; however, the efficiency is limited when using state of the art open volumetric receivers. Therefore, different types of air receivers are implemented into an indirectly heated solar reforming process and the overall efficiency potential is assessed in the present study. The implemented receivers are an open volumetric cavity receiver, a closed volumetric cavity receiver and a tubular cavity receiver. The open volumetric cavity receiver and tubular cavity receiver achieve the best results due to their capability of operating efficiently at temperatures well above 700 °C. For these receivers peak efficiencies up to 29% and 27% respectively are predicted. As the utilization of an open volumetric cavity receiver constitutes an open heat transfer

Efficient Conversation: The Talk between Pilots and Air Traffic Controllers.

Science.gov (United States)

Simmons, James L.

Two-way radio communications between air traffic controllers using radar on the ground to give airplane pilots instructions are of interest within the developing framework of the sociology of language. The main purpose of air traffic control language is efficient communication to promote flight safety. This study describes the standardized format…

High Efficiency, Transparent, Reusable, and Active PM2.5 Filters by Hierarchical Ag Nanowire Percolation Network.

Science.gov (United States)

Jeong, Seongmin; Cho, Hyunmin; Han, Seonggeun; Won, Phillip; Lee, Habeom; Hong, Sukjoon; Yeo, Junyeob; Kwon, Jinhyeong; Ko, Seung Hwan

2017-07-12

Air quality has become a major public health issue in Asia including China, Korea, and India. Particulate matters are the major concern in air quality. We present the first environmental application demonstration of Ag nanowire percolation network for a novel, electrical type transparent, reusable, and active PM2.5 air filter although the Ag nanowire percolation network has been studied as a very promising transparent conductor in optoelectronics. Compared with previous particulate matter air filter study using relatively weaker short-range intermolecular force in polar polymeric nanofiber, Ag nanowire percolation network filters use stronger long-range electrostatic force to capture PM2.5, and they are highly efficient (>99.99%), transparent, working on an active mode, low power consumption, antibacterial, and reusable after simple washing. The proposed new particulate matter filter can be applied for a highly efficient, reusable, active and energy efficient filter for wearable electronics application.

Relative dose efficiencies of antiscatter grids and air gaps in pediatric radiography

International Nuclear Information System (INIS)

McDaniel, D.L.; Cohen, G.; Wagner, L.K.; Robinson, L.H.

1984-01-01

The relative dose efficiencies (RDE) of various antiscatter grids and air gaps were determined for conditions simulating those found in pediatric radiography, using phantoms representing a newborn child, a 5-yr-old and a 10-yr-old child. Our data indicate than an air gap is best for the newborn, due to the low levels of scatter. The 8:1 fiber grid or 15.2-cm air gap without a grid can improve dose efficiency (DE) for the 5-yr-old child by 20%--25% relative to the 3.3-cm air gap and no-grid technique, while for the 10-yr-old child, DE can be improved by 40% with an 8:1 fiber grid

Robust Sliding Mode Control of Air Handling Unit for Energy Efficiency Enhancement

Directory of Open Access Journals (Sweden)

Awais Shah

2017-11-01

Full Text Available In order to achieve feasible and copacetic low energy consuming building, a robust and efficient air conditioning system is necessary. Since heating ventilation and air conditioning systems are nonlinear and temperature and humidity are coupled, application of conventional control is inappropriate. A multi-input multi-output nonlinear model is presented. The temperature and humidity of thermal zone are ascendance by the manipulation of the water and air flow rates. A sliding mode controller (SMC is designed to ensure robust performance of air handling unit in the presence of uncertainties. A simple proportional-integral-derivative (PID controller is used as a comparison template to highlight the efficiency of the proposed controller. To accomplish tracking targets, a variety of desired temperature and relative humidity commands (including ramp and combination with sequence of steps are investigated. According to simulation results, SMC transcends the PID controller in terms of settling time, steady state and rise time, which makes SMC more energy efficient.

Development and evaluation of a cleanable high efficiency steel filter

International Nuclear Information System (INIS)

Bergman, W.; Larsen, G.; Weber, F.; Wilson, P.; Lopez, R.; Valha, G.; Conner, J.; Garr, J.; Williams, K.; Biermann, A.; Wilson, K.; Moore, P.; Gellner, C.; Rapchun, D.; Simon, K.; Turley, J.; Frye, L.; Monroe, D.

1993-01-01

We have developed a high efficiency steel filter that can be cleaned in-situ by reverse air pulses. The filter consists of 64 pleated cylindrical filter elements packaged into a 6l0 x 6l0 x 292 mm aluminum frame and has 13.5 m 2 of filter area. The filter media consists of a sintered steel fiber mat using 2 μm diameter fibers. We conducted an optimization study for filter efficiency and pressure drop to determine the filter design parameters of pleat width, pleat depth, outside diameter of the cylinder, and the total number of cylinders. Several prototype cylinders were then built and evaluated in terms of filter cleaning by reverse air pulses. The results of these studies were used to build the high efficiency steel filter. We evaluated the prototype filter for efficiency and cleanability. The DOP filter certification test showed the filter has a passing efficiency of 99.99% but a failing pressure drop of 0.80 kPa at 1,700 m 3 /hr. Since we were not able to achieve a pressure drop less than 0.25 kPa, the steel filter does not meet all the criteria for a HEPA filter. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned by reverse air pulses. The next phase of the prototype evaluation consisted of installing the unit and support housing in the exhaust duct work of a uranium grit blaster for a field evaluation at the Y-12 Plant in Oak Ridge, TN. The grit blaster is used to clean the surface of uranium parts and generates a cloud of UO 2 aerosols. We used a 1,700 m 3 /hr slip stream from the 10,200 m 3 /hr exhaust system

Collecting performance of an evacuated tubular solar high-temperature air heater with concentric tube heat exchanger

International Nuclear Information System (INIS)

Wang, Ping-Yang; Li, Shuang-Fei; Liu, Zhen-Hua

2015-01-01

Highlights: • A novel evacuated tube solar high temperature air heater is designed. • The solar air heater system consists of 30 linked collecting units. • Every unit consisted of a evacuated tube, a simplified CPC and concentric tube. • The flow air is heated over temperature of 200 °C. - Abstract: A set of evacuated tube solar high temperature air heaters with simplified CPC (compound parabolic concentrator) and concentric tube heat exchanger is designed to provide flow air with a temperature of 150–230 °C for industrial production. The solar air heater system consists of 30 linked collecting units. Each unit includes a simplified CPC and an all-glass evacuated tube absorber with a concentric copper tube heat exchanger installed inside. A stainless steel mesh layer with high thermal conductivity is filled between the evacuated tube and the concentric copper tube. Air passes through each collecting unit, and its temperature increases progressively. An experimental investigation of the thermal performance of the air heater is performed, and the experimental results demonstrate the presented high-temperature solar air heater has excellent collecting performance and large output power, even in the winter. The measured thermal efficiency corresponding to the air temperature of 70 °C reaches 0.52. With the increase of air temperature, thermal efficiency reaches 0.35 at an air temperature of 150 °C, and 0.21 at an air temperature of 220 °C.

Air cleaning efficiency of deodorant materials under dynamic conditions: effect of air flow rate

DEFF Research Database (Denmark)

Mizutani, Chiyomi; Bivolarova, Mariya Petrova; Melikov, Arsen Krikor

2014-01-01

Unpleasant odor is a serious problem in hospitals and elderly facilities. One of the unpleasant odors is ammonia originating from human urine and sweat. The air cleaning efficiency of porous activated carbon fiber fabric which has been treated with acid, and porous activated carbon fiber fabric...... mixed with ammonia gas at a concentration of 20 ppm and velocities of 0.05, 0.15, 0.3 and 1.2 m/s. The activated carbon fibers treated with acid had a high deodorizing effect for ammonia (0.8) at a velocity of 0.05 m/s. The deodorizing effect of this material decreased with the increase in the velocity....... The porous activated carbon fiber fabric did not have a deodorant effect....

A resource allocation model to support efficient air quality ...

African Journals Online (AJOL)

Efficient implementation of policies and strategies require that ... †Graduate School of Business Leadership, University of South Africa, P.O. Box 392, Pretoria, 0003, .... and source, emissions, air quality and meteorological data reporting.

Effect of process parameters on energy performance of spray drying with exhaust air heat recovery for production of high value particles

International Nuclear Information System (INIS)

Julklang, Wittaya; Golman, Boris

2015-01-01

Highlights: • We study heat recovery from spray dryer using air-to-air heat exchanger. • We examine dryer energy performance using advanced mathematical model. • We use the response surface methodology to study the effect of process parameters. • Energy efficiency up to 43.3% is obtained at high flow rate of dilute slurry. • Energy saving up to 52.4% is obtained at high drying air temperature. - Abstract: Spray drying process has been widely used in various industries for many decades for production of numerous materials. This paper explores the energy performance of an industrial scale spray dryer equipped with an exhaust air heat recovery system for production of high value particles. Energy efficiency and energy saving were calculated using a comprehensive mathematical model of spray drying. The response surface methodology (RSM) was utilized to study the effect of process parameters on energy performance using a space-filling design. The meta model equations were formulated employing the well-fitted response surface equations with adjusted R 2 larger than 0.995. The energy efficiency as high as 43.3% was obtained at high flow rate of dilute slurry, while the highest energy saving of 52.4% was found by combination of positive effect of drying air temperature and negative effect of slurry mass flow rate. The utilization of efficient air-to-air heat exchanger leads to an increase in energy efficiency and energy savings. The detailed temperature and vapor concentration profiles obtained with the model are also valuable in determining final product quality when spray dryer is operated at energy efficient conditions

Comparison of high efficiency particulate filter testing methods

International Nuclear Information System (INIS)

1985-01-01

High Efficiency Particulate Air (HEPA) filters are used for the removal of submicron size particulates from air streams. In nuclear industry they are used as an important engineering safeguard to prevent the release of air borne radioactive particulates to the environment. HEPA filters used in the nuclear industry should therefore be manufactured and operated under strict quality control. There are three levels of testing HEPA filters: i) testing of the filter media; ii) testing of the assembled filter including filter media and filter housing; and iii) on site testing of the complete filter installation before putting into operation and later for the purpose of periodic control. A co-ordinated research programme on particulate filter testing methods was taken up by the Agency and contracts were awarded to the Member Countries, Belgium, German Democratic Republic, India and Hungary. The investigations carried out by the participants of the present co-ordinated research programme include the results of the nowadays most frequently used HEPA filter testing methods both for filter medium test, rig test and in-situ test purposes. Most of the experiments were carried out at ambient temperature and humidity, but indications were given to extend the investigations to elevated temperature and humidity in the future for the purpose of testing the performance of HEPA filter under severe conditions. A major conclusion of the co-ordinated research programme was that it was not possible to recommend one method as a reference method for in situ testing of high efficiency particulate air filters. Most of the present conventional methods are adequate for current requirements. The reasons why no method is to be recommended were multiple, ranging from economical aspects, through incompatibility of materials to national regulations

High efficiency particulate removal with sintered metal filters

International Nuclear Information System (INIS)

Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

1981-01-01

Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble-free operation. Subsequence pilot scale testing was performed with flyash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 vol % water vapor in the gas stream

Future air conditioning energy consumption in developing countries and what can be done about it: the potential of efficiency in the residential sector

Energy Technology Data Exchange (ETDEWEB)

McNeil, Michael A.; Letschert, Virginie E. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory (United States)

2007-07-01

The dynamics of air conditioning are of particular interest to energy analysts, both because of the high energy consumption of this product, but also its disproportionate impact on peak load. This paper addresses the special role of this end use as a driver of residential electricity consumption in rapidly developing economies. Recent history has shown that air conditioner ownership grows more rapidly than economic growth in warm-climate countries. In 1990, less than a percent of urban Chinese households owned an air conditioner; by 2003 this number rose to 62 %. The evidence suggests a similar explosion of air conditioner use in many other countries is not far behind. Room air conditioner purchases in India are currently growing at 20 % per year, with about half of these purchases attributed to the residential sector. This paper draws on two distinct methodological elements to assess future residential air conditioner 'business as usual' electricity consumption by country/region and to consider specific alternative 'high efficiency' scenarios. The first component is an econometric ownership and use model based on household income, climate and demographic parameters. The second combines ownership forecasts and stock accounting with geographically specific efficiency scenarios within a unique analysis framework (BUENAS) developed by LBNL. The efficiency scenario module considers current efficiency baselines, available technologies, and achievable timelines for development of market transformation programs, such as minimum efficiency performance standards (MEPS) and labeling programs. The result is a detailed set of consumption and emissions scenarios for residential air conditioning.

Numerical analysis of the efficiency of earth to air heat exchange systems in cold and hot-arid climates

International Nuclear Information System (INIS)

Fazlikhani, Faezeh; Goudarzi, Hossein; Solgi, Ebrahim

2017-01-01

Highlights: • A numerical model is developed to evaluate performance of earth to air heat exchanger. • The cooling/heating potential of earth to air heat exchanger is investigated in hot-dry and cold climates. • The more performance of earth to air heat exchanger in hot-dry climates compared to cold climates. • The high efficiency of earth to air heat exchanger for pre-heating in both hot-dry and cold climates. - Abstract: In order to examine and compare the efficiency of earth to air heat exchanger (EAHE) systems in hot-arid (Yazd) and cold (Hamadan) climates in Iran a steady state model was developed to evaluate the impact of various parameters including inlet air temperatures, pipe lengths and ground temperatures on the cooling and heating potential of EAHEs in both climates. The results demonstrated the ability of the system to not only improve the average temperature and decrease the temperature fluctuation of the outlet air temperature of EAHE, but also to trigger considerable energy saving. It was found that in both climates, the system is highly utilized for pre-heating, and its usage is unfeasible in certain periods throughout the year. In winter, EAHEs have the potential of increasing the air temperature in the range of 0.2–11.2 °C and 0.1–17.2 °C for Yazd and Hamadan, respectively. However, in summer, the system decreases the air temperature for the aforementioned cities in the range of 1.3–11.4 °C and 5.7–11.1 °C, respectively. The system ascertains to be more efficient in the hot-arid climate of Yazd, where it can be used on 294 days of the year, leading to 50.1–63.6% energy saving, when compared to the cold climate of Hamadan, where it can be used on 225 days of the year resulting in a reduction of energy consumption by 24.5–47.9%.

Indoor air-quality measurements in energy-efficient residential buildings

Energy Technology Data Exchange (ETDEWEB)

Berk, J.V.; Hollowell, C.D.; Pepper, J.H.; Young, R.

1980-05-01

The potential impact on indoor air quality of energy-conserving measures that reduce ventilation is being assessed in a field-monitoring program conducted by the Lawrence Berkeley Laboratory. Using a mobile laboratory, on-site monitoring of infiltration rate, carbon dioxide, carbon monoxide, nitrogen dioxide, nitric oxide, ozone, sulfur dioxide, formaldehyde, total aldehydes, and particulates was conducted in three houses designed to be energy-efficient. Preliminary results show that energy-conserving design features that reduce air-exchange rates compromise indoor air quality; specifically, indoor levels of several pollutants were found to exceed levels detected outdoors. Although the indoor levels of most pollutants are within limits established by present outdoor air-quality standards, considerable work remains to be accomplished before health-risk effects can be accurately assessed and broad-scale regulatory guidelines revised to comply with energy-conservation goals.

Highly Polluted Wastewaters Treatment by Improved Dissolved Air Flotation Technology

Science.gov (United States)

Moga, I. C.; Covaliu, C. I.; Matache, M. G.; Doroftei, B. I.

2017-06-01

Numerous investigations are oriented towards the development of new wastewater treatment technologies, having high efficiencies for removing even low concentrations of pollutants found in water. These efforts were determined by the destroyer impact of the pollutants to the environment and human’s health. For this reason this paper presents our study concerning an improved dissolved air flotation technology for wastewater treatment. There is described a dissolved air flotation (DAF) installation composed by two equipments: pressurized capsule and lamellar settling. Also, there are presented some advantages of using nanoparticles as flotation collectors.

Evaluating co-benefits of energy efficiency and air pollution abatement in China’s cement industry

International Nuclear Information System (INIS)

Zhang, Shaohui; Worrell, Ernst; Crijns-Graus, Wina

2015-01-01

Highlights: • Implementation rates of 37 EEMs are quantified for China’s cement industry. • Energy Supply Cost Curves were implemented in the GAINS model. • The economic energy saving potential is 3.0 EJ and costs is $4.1 billion in 2030. • Energy efficiency would lead to large reductions in air pollution. • The co-benefits decrease average marginal costs of EEMs by 20%. - Abstract: China’s cement industry is the world’s largest and is one of the largest energy consuming, and GHG and air pollutant emitting industries. Actions to improve energy efficiency by best available technology can often bring co-benefits for climate change and air quality through reducing emissions of GHGs and air pollutants emission. In this study, the energy conservation supply curves (ECSC) combined with the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) was used to estimate the co-benefits of energy savings on CO 2 and air pollutants emission for implementing co-control options of energy efficiency measures and end-of-pipe options in the China’s cement industry for the period 2011–2030. Results show that there are large co-benefits of improving energy efficiency and reducing emissions of CO 2 and air pollutants for the China’s cement industry during the study period. The cost-effective energy saving potential (EEP1 scenario) and its costs is estimated to be 3.0 EJ and 4.1 billion $ in 2030. The technical energy savings potential (EEP2 scenario) and its costs amount to 4.2 EJ and 8.4 billion $ at the same time. Compared to the baseline scenario, energy efficiency measures can help decrease 5% of CO 2 , 3% of PM, 15% of SO 2 , and 12% of NOx emissions by 2030 in EEP1 scenario. If we do not consider costs (EEP2 scenario), energy efficiency measures can further reduce 3% of CO 2 , 2% of PM, 10% of SO 2 , and 8% of NOx by 2030. Overall, the average marginal costs of energy efficiency measures will decrease by 20%, from 1.48 $/GJ to 1.19 $/GJ, when

Potential CO{sub 2} reduction by implementing energy efficiency standard for room air conditioner in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Mahlia, T.M.I.; Masjuki, H.H.; Choudhury, I.A.; Saidur, R. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2001-09-01

This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment. (Author)

High efficiency particulate air filter experience survey

International Nuclear Information System (INIS)

Carbaugh, E.H.

1983-01-01

Causes and magnitude of HEPA filter changeouts and failures at DOE sites for the years 1977 to 1979 were evaluated. Conclusions inferred from the data follow: HEPA filters have been generally performing the task they were designed for; most changeouts have been made because of filter plugging, preventive maintenance, or precautionary reasons rather than evidence of filter failure; where failures have been experienced, records generally have not been adequate to determine the cause of failure; where cause of failure has been determined, damage attributed to personnel handling and installation has been substantially more prevalent than that from filter environmental exposure. The need for improved personnel training in handling and installation was stressed. Some reduction in filter failure frequency can be achieved by improving the acid and moisture resistance of filters, and providing adequate pretreatment of air prior to HEPA filtration

Energy Efficiency in Buildings as an Air Quality Compliance Approach: Opportunities for the U.S. Department of Energy

Energy Technology Data Exchange (ETDEWEB)

Vine, Edward

2002-05-01

Increasing the energy efficiency of end-use equipment in the residential, commercial, and industrial sectors can reduce air pollution emissions and greenhouse gases significantly. Because energy efficiency is an effective means of reducing multi-pollutant emissions, it is important to ensure that energy efficiency is a fully engaged component of emission-reduction programs. However, while energy-efficiency measures are perceived by many stakeholders to be important options for improving air quality, some members in the air quality community are concerned about the ability of these measures to fit in a regulatory framework-in particular, the ability of emissions reductions from energy-efficiency measures to be real, quantifiable, certifiable, and enforceable. Hence, there are few air quality programs that include energy efficiency as a tool for complying with air quality regulations. This paper describes the connection between energy consumption and air quality, the potential role of energy-efficiency measures to meet air quality regulations, the barriers and challenges to the use of these measures in the air quality regulatory environment, and the potential role that the U.S. Department of Energy's (USDOE) Energy Efficiency and Renewable Energy's Building Technology, State and Community Programs (EERE-Buildings) could play in this area. EERE-Buildings can play a very important role in promoting energy efficiency in the air quality community, in ways that are fully consistent with its overall mission. EERE-Buildings will need to work with other stakeholders to aggressively promote energy efficiency via multiple means: publications, analytical tools, pilot programs, demonstrations, and program and policy analysis and evaluation. EERE-Buildings and state energy officials have considerable experience in implementing and monitoring energy-savings projects, as well as in designing documentation and verification requirements of energy-efficiency improvements

Theoretical and Experimental Investigations of Highly Uprated Diesel Engine with Temperature Regulator of Supercharging Air

Directory of Open Access Journals (Sweden)

G. A. Vershina

2005-01-01

Full Text Available Mathematical model of a highly uprated diesel engine with turbo-supercharging and intercooler of supercharging air is given in die paper. Theoretical study based on the model has made it possible to design and test an intercooler with a temperature regulator of supercharging air. Test results prove efficiency of temperature regulation of supercharging air in operation of an engine at low loads with excess air factor more than 3.2.

Evaporative Air Coolers Optimization for Energy Consumption Reduction and Energy Efficiency Ratio Increment

OpenAIRE

Leila Torkaman; Nasser Ghassembaglou

2015-01-01

Significant quota of Municipal Electrical Energy consumption is related to Decentralized Air Conditioning which is mostly provided by evaporative coolers. So the aim is to optimize design of air conditioners to increase their efficiencies. To achieve this goal, results of practical standardized tests for 40 evaporative coolers in different types collected and simultaneously results for same coolers based on one of EER (Energy Efficiency Ratio) modeling styles are figured ...

Evaluating performance of high efficiency mist eliminators

Energy Technology Data Exchange (ETDEWEB)

Waggoner, Charles A.; Parsons, Michael S.; Giffin, Paxton K. [Mississippi State University, Institute for Clean Energy Technology, 205 Research Blvd, Starkville, MS (United States)

2013-07-01

Processing liquid wastes frequently generates off gas streams with high humidity and liquid aerosols. Droplet laden air streams can be produced from tank mixing or sparging and processes such as reforming or evaporative volume reduction. Unfortunately these wet air streams represent a genuine threat to HEPA filters. High efficiency mist eliminators (HEME) are one option for removal of liquid aerosols with high dissolved or suspended solids content. HEMEs have been used extensively in industrial applications, however they have not seen widespread use in the nuclear industry. Filtering efficiency data along with loading curves are not readily available for these units and data that exist are not easily translated to operational parameters in liquid waste treatment plants. A specialized test stand has been developed to evaluate the performance of HEME elements under use conditions of a US DOE facility. HEME elements were tested at three volumetric flow rates using aerosols produced from an iron-rich waste surrogate. The challenge aerosol included submicron particles produced from Laskin nozzles and super micron particles produced from a hollow cone spray nozzle. Test conditions included ambient temperature and relative humidities greater than 95%. Data collected during testing HEME elements from three different manufacturers included volumetric flow rate, differential temperature across the filter housing, downstream relative humidity, and differential pressure (dP) across the filter element. Filter challenge was discontinued at three intermediate dPs and the filter to allow determining filter efficiency using dioctyl phthalate and then with dry surrogate aerosols. Filtering efficiencies of the clean HEME, the clean HEME loaded with water, and the HEME at maximum dP were also collected using the two test aerosols. Results of the testing included differential pressure vs. time loading curves for the nine elements tested along with the mass of moisture and solid

Dual fan, dual-duct system meets air quality, energy-efficiency needs

Energy Technology Data Exchange (ETDEWEB)

Schuler, M. [Pageau Morel and Associates, Montreal, Quebec (Canada)

1996-03-01

Canada`s Space Centre in Saint-Hubert Quebec is a 300,000 ft{sup 2} (27,871 m{sup 2}) complex that houses the headquarters of the Canadian Space Agency, the Canadian Astronaut Training Centre, mission ground control installations, research facilities, offices and the required support facilities. A comfortable, pleasant research environment was a primary concern for the Space Centre, given its elite clientele. The objectives were high indoor-air quality, design flexibility, energy efficiency and low capital costs. Dual duct systems which are the heart of the mechanical concept allowed the designers to meet these objectives. The Space Centre`s offices, laboratories and conference center are all served by dual-duct systems. All operate using an air economizer cycle. Gas boilers provide them with hot water for heating and steam for humidification while centrifugal chillers provide chilled water for cooling. This article describes the design.

Air flow optimization for energy efficient blower of biosafety cabinet class II A2

Science.gov (United States)

Ibrahim, M. D.; Mohtar, M. Z.; Alias, A. A.; Wong, L. K.; Yunos, Y. S.; Rahman, M. R. A.; Zulkharnain, A.; Tan, C. S.; Thayan, R.

2017-04-01

An energy efficient Biosafety Cabinet (BSC) has become a big challenge for manufacturers to develop BSC with the highest level of protection. The objective of research is to increase air flow velocity discharge from centrifugal blower. An aerodynamic duct shape inspired by the shape of Peregrine Falcon’s wing during diving flight is added to the end of the centrifugal blower. Investigation of air movement is determined by computational fluid dynamics (CFD) simulation. The results showed that air velocity can be increased by double compared to typical manufactured BSC and no air recirculation. As conclusion, a novel design of aerodynamic duct shape successfully developed and proved that air velocity can be increase naturally with same impeller speed. It can contribute in increasing energy efficiency of the centrifugal blower. It is vital to BSC manufacturer and can be apply to Heating, Air Ventilation and Air Conditioning (HVAC) industries.

Performance and stability of a liquid anode high-temperature metal-air battery

Science.gov (United States)

Otaegui, L.; Rodriguez-Martinez, L. M.; Wang, L.; Laresgoiti, A.; Tsukamoto, H.; Han, M. H.; Tsai, C.-L.; Laresgoiti, I.; López, C. M.; Rojo, T.

2014-02-01

A High-Temperature Metal-Air Battery (HTMAB) that operates based on a simple redox reaction between molten metal and atmospheric oxygen at 600-1000 °C is presented. This innovative HTMAB concept combines the technology of conventional metal-air batteries with that of solid oxide fuel cells to provide a high energy density system for many applications. Electrochemical reversibility is demonstrated with 95% coulomb efficiency. Cell sealing has been identified as a key issue in order to determine the end-of-charge voltage, enhance coulomb efficiency and ensure long term stability. In this work, molten Sn is selected as anode material. Low utilization of the stored material due to precipitation of the SnO2 on the electrochemically active area limits the expected capacity, which should theoretically approach 903 mAh g-1. Nevertheless, more than 1000 charge/discharge cycles are performed during more than 1000 h at 800 °C, showing highly promising results of stability, reversibility and cyclability.

Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers.

Science.gov (United States)

Tu, Y D; Wang, R Z; Ge, T S; Zheng, X

2017-01-12

Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8-3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump's efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications.

Experimental method to reveal the effect of rotor magnet size and air gap on artificial heart driving motor torque and efficiency.

Science.gov (United States)

Qian, K X; Yuan, H Y; Ru, W M; Zeng, P

2002-01-01

To investigate experimentally the effect of rotor magnet design on artificial heart driving motor performance, seven rotors with different magnet lengths or thicknesses, as well as different peripheral angles, were manufactured and tested in the same motor stator with different rotating speeds. The input power (voltage and current) and output torque were measured and the motor efficiency was computed. The results demonstrated that the reduction of rotor magnet size and the enlargement of the air gap between the rotor magnets and the stator coil core have no significant effect on motor efficiency, but will reduce the torque value on which the motor achieves the highest efficiency; it could be remedied however by increasing the rotating speed, because the torque at the high efficiency point will increase along with the rotating speed. These results may provide a basis for developing small rotor magnets, large air gap and high efficiency motors for driving an artificial heart pump.

Air purification in industrial plants producing automotive rubber components in terms of energy efficiency

Directory of Open Access Journals (Sweden)

Grzebielec Andrzej

2017-04-01

Full Text Available In automotive industry plants, which use injection molding machines for rubber processing, tar contaminates air to such an extent that air fails to enter standard heat recovery systems. Accumulated tar clogs ventilation heat recovery exchangers in just a few days. In the plant in which the research was conducted, tar contamination causes blockage of ventilation ducts. The effect of this phenomenon was that every half year channels had to be replaced with new ones, since the economic analysis has shown that cleaning them is not cost-efficient. Air temperature inside such plants is often, even in winter, higher than 30°C. The air, without any means of heat recovery, is discharged outside the buildings. The analyzed plant uses three types of media for production: hot water, cold water at 14°C (produced in a water chiller, and compressed air, generated in a unit with a rated power consumption of 180 kW. The aim of the study is to determine the energy efficiency improvement of this type of manufacturing plant. The main problem to solve is to provide an air purification process so that air can be used in heat recovery devices. The next problem to solve is to recover heat at such a temperature level that it would be possible to produce cold for technological purposes without air purification. Experimental studies have shown that air purification is feasible. By using one microjet head, a total of 75% of tar particles was removed from the air; by using 4 heads, a purification efficiency of 93% was obtained. This method of air purification causes air temperature to decrease from 35°C to 20°C, which significantly reduces the potential for heat recovery. The next step of the research was designing a cassette-plate heat exchanger to exchange heat without air purification. The economic analysis of such a solution revealed that replacing the heat exchanger with a new one even once a year was not cost-efficient. Another issue examined in the context of

Achieving better energy-efficient air conditioning – A review of technologies and strategies

International Nuclear Information System (INIS)

Chua, K.J.; Chou, S.K.; Yang, W.M.; Yan, J.

2013-01-01

Air conditioning is essential for maintaining thermal comfort in indoor environments, particularly for hot and humid climates. Today, air conditioning, comprising cooling and dehumidification, has become a necessity in commercial and residential buildings and industrial processes. It accounts for a major share of the energy consumption of a building or facility. In tropical climates, the energy consumed by heating, ventilation and air-conditioning (HVAC) can exceed 50% of the total energy consumption of a building. This significant figure is primarily due to the heavy duty placed on cooling technologies to remove both sensible and latent heat loads. Therefore, there is tremendous potential to improve the overall efficiency of the air-conditioning systems in buildings. Based on today’s practical technology for cooling, the major components of a chiller plant are (1) compressors, (2) cooling towers, (3) pumps (chilled and cooling water) and (4) fans in air handling units. They all consume mainly electricity to operate. When specifying the kW/R ton of a plant, there are two levels of monitoring cooling efficiency: (1) at the efficiency of the chiller machines or the compressors which consume a major amount of electricity; and (2) at the overall efficiency of cooling plants which include the cooling towers, pumps for moving coolant (chilled and cooling water) to all air-handling units. Pragmatically, a holistic approach is necessary towards achieving a low energy input per cooling achieved such as 0.6 kW/R ton cooling or lower by considering all aspects of the cooling plant. In this paper, we present a review of recent innovative cooling technology and strategies that could potentially lower the kW/R ton of cooling systems – from the existing mean of 0.9 kW/R ton towards 0.6 kW/R ton or lower. The paper, broadly divided into three key sections (see Fig. 2), begins with a review of the recent novel devices that enhances the energy efficiency of cooling systems at

A resource allocation model to support efficient air quality ...

African Journals Online (AJOL)

Research into management interventions that create the required enabling environment for growth and development in South Africa are both timely and appropriate. In the research reported in this paper, the authors investigated the level of efficiency of the Air Quality Units within the three spheres of government viz.

Co-benefits of energy efficiency improvement and air pollution abatement in the Chinese iron and steel industry

International Nuclear Information System (INIS)

Zhang, Shaohui; Worrell, Ernst; Crijns-Graus, Wina; Wagner, Fabian; Cofala, Janusz

2014-01-01

In 2010, China was responsible for 45% of global steel production, while consuming 15.8 EJ of final energy and emitting 1344 Mt CO 2eq , 8.4 Mt of PM (particulate matter) emissions, and 5.3 Mt of SO 2 emissions. In this paper we analyse the co-benefits of implementing energy efficiency measures that jointly reduce greenhouse gas emissions and air pollutants, in comparison to applying only air pollution control (end-of-pipe technology). For this purpose we construct ECSC (energy conservation supply curves) that contain potentials and costs of energy efficiency measures and implement these in the GAINS (greenhouse gas and air pollution interactions and synergies) model. Findings show that the technical energy saving potential for the Chinese iron and steel industry for 2030 is around 5.7 EJ. This is equivalent to 28% of reference energy use in 2030. The emissions mitigation of GHGs (greenhouse gases) and air pollutants in BAEEM S 3 scenario would be reduce 27% CO 2 eq, 3% of PM, and 22% of SO 2 , compared to the BL scenario in 2030. Investments and cost savings were calculated for different scenarios, showing that energy efficiency investments will result in significant reductions in air pollution control costs. Hence, Energy efficiency measures should be integrated in air quality policy in China. - Highlights: • Implementation rates of 56 EEMs (energy efficiency measures) are quantified in China's Iron and steel industry. • Energy Supply Cost Curve was implemented in the GAINS (greenhouse gas and air pollution interactions and synergies) model. • The contribution of energy efficiency measure on the process level was estimated. • There are large co-benefits of improving energy efficiency and reducing emissions. • EEMs (energy efficiency measures) would lead to huge reductions in air pollution

Product lifetime, energy efficiency and climate change: A case study of air conditioners in Japan.

Science.gov (United States)

Nishijima, Daisuke

2016-10-01

This study proposed a modelling technique for estimating life-cycle CO2 emissions of durable goods by considering changes in product lifetime and energy efficiency. The stock and flow of durable goods was modelled by Weibull lifetime distributions and the trend in annual energy efficiency (i.e., annual electricity consumption) of an "average" durable good was formulated as a reverse logistic curve including a technologically critical value (i.e., limit energy efficiency) with respect to time. I found that when the average product lifetime is reduced, there is a trade-off between the reduction in emissions during product use (use phase), due to the additional purchases of new, more energy-efficient air conditioners, and the increase in emissions arising from the additional production of new air conditioners stimulated by the reduction of the average product lifetime. A scenario analysis focused on residential air conditioners in Japan during 1972-2013 showed that for a reduction of average lifetime of 1 year, if the air conditioner energy efficiency limit can be improved by 1.4% from the estimated current efficiency level, then CO2 emissions can be reduced by approximately the same amount as for an extension of average product lifetime of 1 year. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-efficiency particulate air (HEPA) filter performance following service and radiation exposure

International Nuclear Information System (INIS)

Jones, L.R.

1975-01-01

Small HEPA filters were exposed to a 60 Co source with a radiation strength of 3 x 10 7 rads per hour and then exposed to steam--air mixtures at several times filter design flow, followed by extended exposure to steam and air at reduced flow. Additional filters were exposed to air flow in a reactor confinement system and then similarly tested with steam--air mixture flows. The test data and calculated effects of filter pluggage with moisture on confinement system performance following potential reactor accidents are described. Gamma radiation exposure impaired the performance of new filters only slightly and temporarily improved performance of service aged filters. Normal confinement system service significantly impaired filter performance although not sufficiently to prevent adequate performance of the SRP confinement system following an unlikely reactor accident. Calculations based on measured filter pluggage indicate that during an accident air flow could be reduced approximately 50 percent with service-degraded HEPA filters present, or approximately 10 percent with new filters damaged by the radiation exposure. (U.S.)

Energy efficient engine high pressure turbine test hardware detailed design report

Science.gov (United States)

Halila, E. E.; Lenahan, D. T.; Thomas, T. T.

1982-01-01

The high pressure turbine configuration for the Energy Efficient Engine is built around a two-stage design system. Moderate aerodynamic loading for both stages is used to achieve the high level of turbine efficiency. Flowpath components are designed for 18,000 hours of life, while the static and rotating structures are designed for 36,000 hours of engine operation. Both stages of turbine blades and vanes are air-cooled incorporating advanced state of the art in cooling technology. Direct solidification (DS) alloys are used for blades and one stage of vanes, and an oxide dispersion system (ODS) alloy is used for the Stage 1 nozzle airfoils. Ceramic shrouds are used as the material composition for the Stage 1 shroud. An active clearance control (ACC) system is used to control the blade tip to shroud clearances for both stages. Fan air is used to impinge on the shroud casing support rings, thereby controlling the growth rate of the shroud. This procedure allows close clearance control while minimizing blade tip to shroud rubs.

Behavior and monitoring of air filters of high efficiency during fire

International Nuclear Information System (INIS)

Chappellier, Andre; Chappellier, Simonne.

1980-07-01

High efficiency filters were submitted to dynamic tests at graduated temperatures. As compared to the case of fire taking place in a high activity building equiped with such purifying system, these tests can be considered as significant. The tested filters were found out to resist to three ranges of temperatures: (1) 130 0 C during one hour, (ii) 250 0 C during one hour, (iii) 400 0 C during at least two hours. Some observed phenomenons, as for instance, the smoke emission due to glues, or building materials pyrolysis will progress the conception doctrine of fire detection network in ventilation sheath. Moreover these tests demonstrated that thermal fire detectors well chosen and correctly put into operation can be useful in these sheaths [fr

Air-Filled Nanopore Based High-Performance Thermal Insulation Materials

OpenAIRE

Gangåssæter, Haakon Fossen; Jelle, Bjørn Petter; Alex Mofid, Sohrab; Gao, Tao

2017-01-01

State-of-the-art thermal insulation solutions like vacuum insulation panels (VIP) and aerogels have low thermal conductivity, but their drawbacks may make them unable to be the thermal insulation solutions that will revolutionize the building industry regarding energy-efficient building envelopes. Nevertheless, learning from these materials may be crucial to make new and novel high-performance thermal insulation products. This study presents a review on the state-of-the-art air-filled thermal...

Daily efficiency of flat-plate solar air collectors for grain drying

Energy Technology Data Exchange (ETDEWEB)

Ting, K.C.; Shove, G.C.

1983-01-01

Single cover flat-plate solar collectors incorporated into walls and roofs of farm buildings have been used to heat ambient air for low temperature grain drying systems. Large surface area and high airflow rate are common features of these collectors. The drying period may range from several days to several weeks. Therefore, a knowledge of the variations of the collectors' daily efficiencies with respect to their design parameters would be helpful in applying solar collectors to grain drying. The objective of this study was to develop a simpler means of direct calculation of a collector's daily efficiency based on its design parameters. Many factors, such as configuration of the collector, airflow rate, weather conditions, etc. will affect the performance of solar collectors. A large number of varied conditions need to be tested in order to investigate the effect of different parameters on the collector performance. To facilitate this investigation, a computer simulation model developed by Ting was used to calculate the daily efficiencies of collectors under different operating conditions. The computer model was verified by Morrison's experimental data. Based on the simulation results, a functional relationship was developed between the daily efficiencies of collectors and their design parameters.

LDDX: A High Efficiency Air Conditioner for DOD Buildings

Science.gov (United States)

2017-02-01

and the entire 2016 cooling season. The LDDX-WF prototype met its performance objectives to supply dry air and to modulate the Sensible Heat Ratio... heat transfer of the desiccant on the fin is an effective substitute for the conductive heat transfer of the aluminum fins used in a conventional...respectively. 22 The May 2014 laboratory operation of the LDDX-WF prototype was the first opportunity to measure heat and mass transfer

Viral Penetration of High Efficiency Particulate Air (HEPA) Filters

Science.gov (United States)

2007-02-01

PVC tubing (Excelon® RNT,US Plastics, Lima , Ohio). Each path runs through a test article and thence through one AGI-30 all-glass impingers (Chemglass...a mechanical flow meter (Blue–White 400, Huntington Beach , California, or PMR1-101346, Cole– Parmer, Vernon Hills, Illinois). At the end of the...fibrous Filters." Air Pollution Control Association 30(4): 377-381. Leenders, G. J. M. and J. H. Stadhouders (1980s). "Effectiveness of HEPA

Air emissions perspective on energy efficiency: An empirical analysis of China’s coastal areas

International Nuclear Information System (INIS)

Qin, Quande; Li, Xin; Li, Li; Zhen, Wei; Wei, Yi-Ming

2017-01-01

Highlights: • We investigate the static and dynamic energy efficiency in China’s coastal areas. • Both environmental pollutants and greenhouse gas are considered. • Global benchmark technology is incorporated into the related DEA models. • China’s coastal areas have great potential of air emissions reduction. • Technological progress is main driven factor to improve energy efficiency. - Abstract: Improving energy efficiency has been recognized as the most effective way to reduce the greenhouse effect and achieve sustainable development. From the perspective of air emissions, this paper adopts data envelopment analysis approach to evaluate the energy efficiency in China’s coastal areas over the period of 2000–2012. Carbon dioxide, sulfur dioxide and nitrogen oxide are treated as undesirable outputs of energy consumptions. The proposed global Epsilon-based measure is used to estimate the static energy efficiency with an annual cross-section of data. The weights of the three undesirable outputs are determined according to their treatment costs. A global Malmquist-Luenberger productivity index based on directional distance function is employed to dynamically evaluate the energy efficiency. The results indicate the following in China’s coastal areas: (1) the level of economic development is positively related to energy efficiency scores; (2) energy efficiency scores decrease when considering undesirable outputs except Beijing and Hainan; (3) the Circum-Bohai Sea Economic Region greatly improves energy efficiency and has great potential of air emission; (4) the annual growth rate of Malmquist-Luenberger productivity index change is overestimated; (5) energy efficiency improvement is mainly driven by technological improvement, and scale efficiency and management level are the main obstacles.

Efficient stratified ventilation - air conditioning of skating rinks; Effiziente Schichtlueftung - Klimatisierung von Eissporthallen

Energy Technology Data Exchange (ETDEWEB)

Fiedler, E. [Fa. Caverion, Aachen (Germany)

2007-07-01

Air conditioning of ice rinks is not just a matter of user comfort. Excessive humidity will cause frosting and poor ice quality while mist formation may interfere with hockey games. Constant condensation in the roof area causes severe damage of the building and is assumed to be a maine cause of the breakdown of the Bad Reichenhall skating hall in January 2006. In the Wolfsburg ice arena, an innovative ventilation concept was implemented which meets complex user demands and is characterized by its high energy efficiency. (orig.)

A resource allocation model to support efficient air quality management in South Africa

Directory of Open Access Journals (Sweden)

U Govender

2009-06-01

Full Text Available Research into management interventions that create the required enabling environment for growth and development in South Africa are both timely and appropriate. In the research reported in this paper, the authors investigated the level of efficiency of the Air Quality Units within the three spheres of government viz. National, Provincial, and Local Departments of Environmental Management in South Africa, with the view to develop a resource allocation model. The inputs to the model were calculated from the actual man-hours spent on twelve selected activities relating to project management, knowledge management and change management. The outputs assessed were aligned to the requirements of the mandates of these Departments. Several models were explored using multiple regressions and stepwise techniques. The model that best explained the efficiency of the organisations from the input data was selected. Logistic regression analysis was identified as the most appropriate tool. This model is used to predict the required resources per Air Quality Unit in the different spheres of government in an attempt at supporting and empowering the air quality regime to achieve improved output efficiency.

Tracking the maximum efficiency point for the FC system based on extremum seeking scheme to control the air flow

International Nuclear Information System (INIS)

Bizon, Nicu

2014-01-01

Highlights: • The Maximum Efficiency Point (MEP) is tracked based on air flow rate. • The proposed Extremum Seeking (ES) control assures high performances. • About 10 kW/s search speed and 99.99% stationary accuracy can be obtained. • The energy efficiency increases with 3–12%, according to the power losses. • The control strategy is robust based on self-optimizing ES scheme proposed. - Abstract: An advanced control of the air compressor for the Proton Exchange Membrane Fuel Cell (PEMFC) system is proposed in this paper based on Extremum Seeking (ES) control scheme. The FC net power is mainly depended on the air and hydrogen flow rate and pressure, and heat and water management. This paper proposes to compute the optimal value for the air flow rate based on the advanced ES control scheme in order to maximize the FC net power. In this way, the Maximum Efficiency Point (MEP) will be tracked in real time, with about 10 kW/s search speed and a stationary accuracy of 0.99. Thus, energy efficiency will be close to the maximum value that can be obtained for a given PEMFC stack and compressor group under dynamic load. It is shown that the MEP tracking allows an increasing of the FC net power with 3–12%, depending on the percentage of the FC power supplied to the compressor and the level of the load power. Simulations shows that the performances mentioned above are effective

Life cycle analysis of retrofitting with high energy efficiency air-conditioner and fluorescent lamp in existing buildings

International Nuclear Information System (INIS)

Techato, Kua-anan; Watts, Daniel J.; Chaiprapat, Sumate

2009-01-01

Life cycle analysis of mercury in discarded low energy efficiency fluorescent lamps (36 W) and of HCFC in air-conditioners (12,000 Btu) removed from service has been conducted in this study. The objective was to find out the environmental impact (EDIP 1997 category, waste evaluation) of the products that appear in the waste stream as a result of facility upgrades. The scope of the study starts from retrofitting of the lamps and air-conditioners through recycling and disposal. For a 36 W fluorescent lamp, the bulk waste 1.64E-5 kg, hazardous waste 1.11E-4 kg, radioactive waste 1.09E-9 kg, and slag-ash 6.02E-7 kg occurred at the end of life of the retrofitting cycle. For a 12,000 Btu air-conditioner, the bulk waste 0.58 kg, hazardous waste 0.11 kg, radioactive waste 0.0002 kg, and slag-ash 0.01 kg also occurred at the end of life of the retrofitting cycle. These small amounts become important when viewed at the country level. These quantities imply that the policy makers who deal with hazardous waste should be aware of this waste-generating characteristic before issuing any pertinent policy. Consideration of this characteristic and planning for appropriate waste management methods at the beginning stage will reduce any future problem of contamination by the hazardous waste

Life cycle analysis of retrofitting with high energy efficiency air-conditioner and fluorescent lamp in existing buildings

Energy Technology Data Exchange (ETDEWEB)

Techato, Kua-anan [International Postgraduate Programs in Environmental Management (Hazardous Waste Management) and ERI (Energy Research Institute), Chulalongkorn University, Bangkok 10330 (Thailand); Watts, Daniel J. [Otto H. York Center for Environmental Engineering and Science, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Chaiprapat, Sumate [Department of Civil Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai Campus, Hat Yai, Songkhla 90112 (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management-Satellite Center at Prince of Songkla University (Thailand)

2009-01-15

Life cycle analysis of mercury in discarded low energy efficiency fluorescent lamps (36 W) and of HCFC in air-conditioners (12,000 Btu) removed from service has been conducted in this study. The objective was to find out the environmental impact (EDIP 1997 category, waste evaluation) of the products that appear in the waste stream as a result of facility upgrades. The scope of the study starts from retrofitting of the lamps and air-conditioners through recycling and disposal. For a 36 W fluorescent lamp, the bulk waste 1.64E-5 kg, hazardous waste 1.11E-4 kg, radioactive waste 1.09E-9 kg, and slag-ash 6.02E-7 kg occurred at the end of life of the retrofitting cycle. For a 12,000 Btu air-conditioner, the bulk waste 0.58 kg, hazardous waste 0.11 kg, radioactive waste 0.0002 kg, and slag-ash 0.01 kg also occurred at the end of life of the retrofitting cycle. These small amounts become important when viewed at the country level. These quantities imply that the policy makers who deal with hazardous waste should be aware of this waste-generating characteristic before issuing any pertinent policy. Consideration of this characteristic and planning for appropriate waste management methods at the beginning stage will reduce any future problem of contamination by the hazardous waste. (author)

Application of porous medium for efficiency improvement of a concentrated solar air heating system

Science.gov (United States)

Prasartkaew, Boonrit

2018-01-01

The objective of this study is to evaluate the thermal efficiency of a concentrated solar collector for a high temperature air heating system. The proposed system consists of a 25-m2 focused multi-flat-mirror solar heliostat equipped with a porous medium solar collector/receiver which was installed on the top of a 3-m tower, called ‘tower receiver’. To know how the system efficiency cloud be improved by using porous medium, the proposed system with and without porous medium were tested and the comparative study was performed. The experimental results reveal that, for the proposed system, application of porous medium is promising, the efficiency can be increased about 2 times compared to the conventional one. In addition, due to the porous medium used in this study was the waste material with very low cost. It can be summarized that the substantial efficiency improvement with very low investment cost of the proposed system seem to be a vital measures for addressing the energy issues.

The Taskload-Efficiency-Safety-Buffer Triangle--development and validation with air traffic management.

Science.gov (United States)

Kallus, K Wolfgang; Hoffmann, Peter; Winkler, Hildegard; Vormayr, Elisabeth M

2010-02-01

The Taskload-Efficiency-Safety-Buffer Triangle (TEST) was developed as a new computerised scaling tool for quickly visualising changes in and trade-offs between the three critical factors that determine the work situation of air traffic management (ATM), i.e. taskload, efficiency and safety-buffers. Based on a task analysis of ATM and backed up by the stress-strain model, an easy-to-interpret triangle was constructed and validated both in simulated and real ATM workplaces. Results from the validation studies show that TEST does not only reflect the most relevant task characteristics, but also provides additional insights in the controllers' working styles. The TEST tool can make ATM safety surveys more efficient and help supervisors to decide about optimal times for opening or closing additional sectors. Statement of Relevance: TEST is a new tool to assess taskload, efficiency and safety-buffers in a joint scaling. It reflects increases in taskload and effects of taskload on safety-buffers and efficiency, as well as trade-offs in opposite directions. This tool might be very useful to check sector capacity in ATM and other high risk environments.

PROBLEMS OF THE EFFICIENCY INCREASING OF TRANSPORTATION BY AIR OF UKRAINIAN SSR (1960-1980

Directory of Open Access Journals (Sweden)

Anatoliy Gorban

2015-11-01

Full Text Available The article is devoted to the problems of the efficiency increasing of the air transportation. The difficulties of increasing the efficiency of transportation by air in Ukrainian SSR in 1960-1980 were researched, factors that adversely affected the organization of the transport sector were determined and depicted. The article analyzes what caused such difficulties and it was found out that the causes of these difficulties are connected with the organizational problems of air transport of Ukrainian SSR, which negatively affected the operation of the industry. The central aim of the research is to focus on the main problems of air transport of Ukrainian SSR. So, we should say that the transport operation of those years was distributed too unevenly and was dependent on the population density of the territory of the republic. Purpose of the article is to determine, compile and analyze the factors that negatively affected the organization of air transportation of the Ukrainian republic and reduced the efficiency of its operation. Results of the research shows technical, organization and economical deficiency of air transport of Ukrainian SSR which caused the ineffectiveness of this type of transport and determines the nature of such difficulties. Statement of the problem. During the specified period (1960–1980 the air transport had undergone rapid development. Many new airlines were opened, airports were being built and reconstructed, the terms of exploiting of turbojet aircrafts were increased, the speed of planes was increasing. All these facts ensured safe and reliable air connection of all district centers, connected Ukraine with the other Soviet republics and foreign countries by air corridors. Ukrainian Department of Civil Aviation became the biggest regional Department of the Ministry of Civil Aviation of the USSR. But, at the same time the intensity of the increase of cargo and passenger transportation since 1970s led to accumulation of

Connectable solar air collectors

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Bosanac, M.

2002-02-01

The project has proved that it is possible to manufacture solar air collector panels, which in an easy way can be connected into large collector arrays with integrated ducting without loss of efficiency. The developed connectable solar air collectors are based on the use of matrix absorbers in the form of perforated metal sheets. Three interconnected solar air collectors of the above type - each with an transparent area of approx. 3 m{sup 2} - was tested and compared with parallel tests on two single solar air collectors also with a transparent area of approx. 3 m{sup 2} One of the single solar air collectors has an identical absorber as the connectable solar air collectors while the absorber of the other single solar air collector was a fibre cloth. The efficiency of the three solar air collectors proved to be almost identical in the investigated range of mass flow rates and temperature differences. The solar air collectors further proved to be very efficient - as efficient as the second most efficient solar air collectors tested in the IEA task 19 project Solar Air Systems. Some problems remain although to be solved: the pressure drop across especially the connectable solar air collectors is too high - mainly across the inlets of the solar air collectors. It should, however, be possible to considerably reduce the pressure losses with a more aerodynamic design of the inlet and outlet of the solar air collectors; The connectable solar air collectors are easy connectable but the air tightness of the connections in the present form is not good enough. As leakage leads to lower efficiencies focus should be put on making the connections more air tight without loosing the easiness in connecting the solar air collectors. As a spin off of the project a simple and easy way to determine the efficiency of solar, air collectors for pre-heating of fresh air has been validated. The simple method of determining the efficiency has with success been compared with an advance method

Future Air Conditioning Energy Consumption in Developing Countriesand what can be done about it: The Potential of Efficiency in theResidential Sector

Energy Technology Data Exchange (ETDEWEB)

McNeil, Michael A.; Letschert, Virginie E.

2007-05-01

The dynamics of air conditioning are of particular interestto energy analysts, both because of the high energy consumption of thisproduct, but also its disproportionate impact on peak load. This paperaddresses the special role of this end use as a driver of residentialelectricity consumption in rapidly developing economies. Recent historyhas shown that air conditioner ownership can grow grows more rapidly thaneconomic growth in warm-climate countries. In 1990, less than a percentof urban Chinese households owned an air conditioner; by 2003 this numberrose to 62 percent. The evidence suggests a similar explosion of airconditioner use in many other countries is not far behind. Room airconditioner purchases in India are currently growing at 20 percent peryear, with about half of these purchases attributed to the residentialsector. This paper draws on two distinct methodological elements toassess future residential air conditioner 'business as usual' electricityconsumption by country/region and to consider specific alternative 'highefficiency' scenarios. The first component is an econometric ownershipand use model based on household income, climate and demographicparameters. The second combines ownership forecasts and stock accountingwith geographically specific efficiency scenarios within a uniqueanalysis framework (BUENAS) developed by LBNL. The efficiency scenariomodule considers current efficiency baselines, available technologies,and achievable timelines for development of market transformationprograms, such as minimum efficiency performance standards (MEPS) andlabeling programs. The result is a detailed set of consumption andemissions scenarios for residential air conditioning.

Securing energy efficiency as a high priority. Scenarios for common appliance electricity consumption in Thailand

Energy Technology Data Exchange (ETDEWEB)

Foran, T. [Unit for Social and Environmental Research USER, Faculty of Social Sciences, Chiang Mai University, P.O. Box 144, Chiang Mai, 50200 (Thailand); Du Pont, P.T. [International Resources Group and Joint Graduate School of Energy and Environment, Bangkok (Thailand); Parinya, P. [The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Phumaraphand, N. [Electricity Generating Authority of Thailand, Nonthaburi (Thailand)

2010-11-15

Between 1995 and 2008, Thailand's energy efficiency programs produced an estimated total of 8,369 GWh/year energy savings and 1,471 MW avoided peak power. Despite these impressive saving figures, relatively little future scenario analysis is available to policy makers. Before the 2008 global financial crisis, electricity planners forecasted 5-6% long-term increases in demand. We explored options for efficiency improvements in Thailand's residential sector, which consumes more than 20% of Thailand's total electricity consumption of 150 TWh/year. We constructed baseline and efficient scenarios for the period 2006-2026, for air conditioners, refrigerators, fans, rice cookers, and compact fluorescent light bulbs. We drew on an appliance database maintained by Electricity Generating Authority of Thailand's voluntary labeling program. For the five appliances modeled, the efficiency scenario results in total savings of 12% of baseline consumption after 10 years and 29% of baseline after 20 years. Approximately 80% of savings come from more stringent standards for air conditioners, including phasing out unregulated air conditioner sales within 6 years. Shifting appliance efficiency standards to current best-in-market levels within 6 years produces additional savings. We discuss institutional aspects of energy planning in Thailand that thus far have limited the consideration of energy efficiency as a high-priority resource.

Nuclear air cleaning

International Nuclear Information System (INIS)

Bellamy, R.R.

1994-01-01

This report briefly describes the history of the use of high- efficiency particulate air filters for air cleaning at nuclear installations in the United States and discusses future uses of such filters

Cost/benefit evaluation of electrofibrous air filters

International Nuclear Information System (INIS)

Bergman, W.; Kuhl, W.; Biermann, A.; Lum, B.

1986-01-01

Experimental electric air filters based on the principle of superimposing an electric field over conventional fibrous air filters have been developed. The different experimental electric filters described in this report include prefilters for use in glove boxes and in ventilation systems, re-circulating air filters, electric HEPA filters, and high efficiency, high temperature air filters. In each case the large improvement in filter efficiency that occurs when a mechanical filter is electrified is demonstrated. Also a significant increase in the particle loading capacity of filters in many of our evaluations is demonstrated. Both laboratory and field test results are presented. This paper also demonstrates that the performance of all of our electric filter designs, except one, can be matched by conventional mechanical air filters and usually at a lower cost. The one exception is the high temperature, high efficiency electric air filter. In that case there is no mechanical filter media that can match the performance of the electric air filter. Our findings show that electric air filters are only cost effective compared to mechanical air filters when the performance of the mechanical air filter cannot be further improved by mechanical means. (author)

Efficiency assessment of indoor environmental policy for air-conditioned offices in Hong Kong

International Nuclear Information System (INIS)

Wong, L.T.; Mui, K.W.

2009-01-01

To reduce carbon dioxide (CO 2 ) emissions through thermal energy conservation, air-conditioned offices in the subtropics are recommended to operate within specified ranges of indoor temperature, relative humidity and air velocity. As thermal discomfort leads to productivity loss, some indoor environmental policies for air-conditioned offices in Hong Kong are investigated in this study with relation to thermal energy consumption, CO 2 emissions from electricity use, and productivity loss due to thermal discomfort. Occupant thermal response is specifically considered as an adaptive factor in evaluating the energy consumption and productivity loss. The energy efficiency of an office is determined by the productivity which corresponds to the CO 2 generated. The results found that a policy with little impact on occupant thermal comfort and worker productivity would improve the office efficiency while the one with excessive energy consumption reduction would result in a substantial productivity loss. This study is a useful reference source for evaluating an indoor thermal environmental policy regarding the energy consumption, CO 2 emissions reduction, thermal comfort and productivity loss in air-conditioned offices in subtropical areas.

Corona ignition system for highly efficient gasoline engines; Corona-Zuendsystem fuer hocheffiziente Ottomotoren

Energy Technology Data Exchange (ETDEWEB)

Burrows, John [Federal-Mogul Limited, Manchester (United Kingdom); Lykowski, Jim; Mixell, Kristapher [Federal-Mogul, Plymouth, MI (United States)

2013-06-01

Many future gasoline engines will require higher air/fuel ratios and higher mean effective pressures to further improve fuel efficiency. Federal-Mogul has taken up this challenge and has developed the Advanced Corona Ignition System (ACIS) as a new solution to reliably ignite a mix with high AFR/EGR and high MEP. During engine tests ACIS enabled a direct fuel economy improvement of up to 10 %. (orig.)

The role of technology, product lifetime, and energy efficiency in climate mitigation: A case study of air conditioners in Japan

International Nuclear Information System (INIS)

Nishijima, Daisuke

2017-01-01

This study analyzed the impact on the life-cycle CO_2 emissions derived from a specific durable good (i.e., household air conditioners in this study) of industrial technology changes, product lifetime changes, and energy efficiency improvements. I proposed a comprehensive structural decomposition analysis including two factors of average lifetime and energy efficiency trend of household air conditioners and applied the decomposition method to the Japanese environmental input-output tables of 1990, 1995, 2000, and 2005. The empirical results show that “Household air-conditioner sector” itself contributed to reducing life-cycle CO_2 emissions derived from household air conditioners, while other sectors such as “On-site power generation sector” and “Retail trade sector” contributed to increasing life-cycle CO_2 emissions derived from household air conditioners. I also conducted combined scenario analysis about reduction potential of product lifetime and energy efficiency of air conditioners and the results showed the reduction rate of energy efficiency necessary for maintain CO_2 emissions in 2005 at 1990 level on each average lifetime scenario. (e.g. if average lifetime of air conditioners is shortened by 1 year, energy efficiency of air conditioners have to be further improved by 20.6% from current level. - Highlights: • This study provides a decomposition framework for air conditioner’s CO_2 emissions. • Technology, product lifetime and energy efficiency are considered in the framework. • “Household air conditioner” sector contributed to reducing CO_2 emissions largely. • “On-site power generation” indirectly contributed to increasing CO_2 emissions. • I showed the improvement rates of energy efficiency to achieve a reduction target.

Modeling energy efficiency to improve air quality and health effects of China's cement industry

NARCIS (Netherlands)

Zhang, Shaohui; Worrell, Ernst|info:eu-repo/dai/nl/106856715; Crijns-Graus, Wina|info:eu-repo/dai/nl/308005015; Krol, Maarten|info:eu-repo/dai/nl/078760410; de Bruine, Marco|info:eu-repo/dai/nl/411965085; Geng, Guangpo; Wagner, Fabian; Cofala, Janusz

2016-01-01

Actions to reduce the combustion of fossil fuels often decrease GHG emissions as well as air pollutants and bring multiple benefits for improvement of energy efficiency, climate change, and air quality associated with human health benefits. The China's cement industry is the second largest energy

High Altitude Clear Air Turbulence Project

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Air Force Flight Dynamics Laboratory conducted the High Altitude Clear Air Turbulence Project in the mid 1960s with the intention of better understanding air...

An Investigation on the Efficiency of Air Purification Using a Biofilter with Activated Bed of Different Origin

Directory of Open Access Journals (Sweden)

Zagorskis Alvydas

2014-12-01

Full Text Available Recent studies in the area of biological air treatment in filters have addressed fundamental key issues, such as a biofilter bed of different origin composed of natural zeolite granules, foam cubes and wood chips. When foam and zeolite are mixed with wood chips to remove volatile organic compounds from the air, not only biological but also adsorption air purification methods are accomplished. The use of complex purification technologies helps to improve the efficiency of a filter as well as the bed service life of the filter bed. Investigations revealed that microorganisms prevailing in biological purification, can also reproduce themselves in biofilter beds of inorganic and synthetic origin composed of natural zeolite and foam. By cultivating associations of spontaneous microorganisms in the filter bed the dependencies of the purification efficiency of filter on the origin, concentration and filtration time of injected pollutants were determined. The highest purification efficiency was obtained when air polluted with acetone vapour was supplied to the equipment at 0.1 m/s of superficial gas velocity. When cleaning air from volatile organic compounds (acetone, toluene and butanol, under the initial pollutant concentration of ~100 mg/m3, the filter efficiency reached 95 %.

Mn-Catalyzed Highly Efficient Aerobic Oxidative Hydroxyazidation of Olefins: A Direct Approach to β-Azido Alcohols.

Science.gov (United States)

Sun, Xiang; Li, Xinyao; Song, Song; Zhu, Yuchao; Liang, Yu-Feng; Jiao, Ning

2015-05-13

An efficient Mn-catalyzed aerobic oxidative hydroxyazidation of olefins for synthesis of β-azido alcohols has been developed. The aerobic oxidative generation of azido radical employing air as the terminal oxidant is disclosed as the key process for this transformation. The reaction is appreciated by its broad substrate scope, inexpensive Mn-catalyst, high efficiency, easy operation under air, and mild conditions at room temperature. This chemistry provides a novel approach to high value-added β-azido alcohols, which are useful precursors of aziridines, β-amino alcohols, and other important N- and O-containing heterocyclic compounds. This chemistry also provides an unexpected approach to azido substituted cyclic peroxy alcohol esters. A DFT calculation indicates that Mn catalyst plays key dual roles as an efficient catalyst for the generation of azido radical and a stabilizer for peroxyl radical intermediate. Further calculation reasonably explains the proposed mechanism for the control of C-C bond cleavage or for the formation of β-azido alcohols.

Reuter Centrifugal Air Sampler: Measurement of Effective Airflow Rate and Collection Efficiency

OpenAIRE

Macher, J. M.; First, M. W.

1983-01-01

Incorrect calculation of effective air sampling rate and disregard of differences in collection efficiency among samplers can lead to false conclusions about the usefulness of samplers for measuring concentrations of airborne microorganisms.

Air-handling energy efficiency and design practices

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Lars J.

1993-12-31

With good design practices and life-cycle cost optimization, specific fan power for individual fans will be between 0.5 and 1kW/m{sup 3}/s. Data from nearly 1000 audited fans in Sweden show that the average measured SFPI weighted by drawn motor power is 1.5 kW/m{sup 3}/s and the situation appears to be similar in other countries. Contract forms used by Swedish builders, and consultants` design practices are analyzed here to search for an explanation to the low performance of installed systems. Identified as two major barriers to efficient system design are the lack of performance specifications when procuring systems and the incentive structure in the building sector. As a consequence, duct design methods, rules of thumb, and vendor recommendations are not leading to system optimization. The broad minima in life cycle costs over a range of air-handling unit sizes show that potential economic welfare losses from efficiency standards are likely to be smaller than the losses that result from today`s design practices. 73 refs, 4 figs, 3 tabs

Air-handling energy efficiency and design practices

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Lars J

1994-12-31

With good design practices and life-cycle cost optimization, specific fan power for individual fans will be between 0.5 and 1kW/m{sup 3}/s. Data from nearly 1000 audited fans in Sweden show that the average measured SFPI weighted by drawn motor power is 1.5 kW/m{sup 3}/s and the situation appears to be similar in other countries. Contract forms used by Swedish builders, and consultants` design practices are analyzed here to search for an explanation to the low performance of installed systems. Identified as two major barriers to efficient system design are the lack of performance specifications when procuring systems and the incentive structure in the building sector. As a consequence, duct design methods, rules of thumb, and vendor recommendations are not leading to system optimization. The broad minima in life cycle costs over a range of air-handling unit sizes show that potential economic welfare losses from efficiency standards are likely to be smaller than the losses that result from today`s design practices. 73 refs, 4 figs, 3 tabs

Development of glass-fiber high-efficiency particulate air filters of high structural strength on the basis of the establishment of failure mechanisms

International Nuclear Information System (INIS)

Ruedinger, V.; Ricketts, C.I.; Wilhelm, J.G.; Alken, W.

1987-01-01

Practical experience from routine operation in nuclear installations as well as extensive bench and laboratory testing proved the structural limits of HEPA filters to be very low thus demonstrating the need for improvement of their structural strength. Detailed analysis of the courses and modes of filter failure under the challenge of dry air at high velocities and ambient temperature, together with additional measurements, allowed the establishment of the dominating mechanisms of filter failure. Based on this information, the following three options for effective and economical improvements in filter structural limits exist: (1) an increase in the tensile strength of the filter medium; (2) an increase in the stability of the pack to prevent the swelling of individual pleats; and (3) an increase in the area moment of inertia of the separators and a decrease in the sharpness of their edges. By using a reinforced glass fiber filter medium, the structural strength of standard size HEPA filters was increased to 31 kPa with dry air and beyond 10 kPa with air at high humidity. Prototype filters built with standard glass-fiber media and separators with inclined corrugations exhibited failure pressures of approximately 50 kPa under high velocity airflows. The combination of both types of improvements, together with other measures, will soon lead to even higher HEPA-filter structural strength

Development of an air cleaning system for dissolving high explosives from nuclear warheads

Energy Technology Data Exchange (ETDEWEB)

Bergman, W.; Wilson, K.; Staggs, K.; Wapman, D. [Lawrence Livermore National Lab., CA (United States)

1997-08-01

The Department of Energy (DOE) has a major effort underway in dismantling nuclear weapons. In support of this effort we have been developing a workstation for removing the high explosive (HE) from nuclear warheads using hot sprays of dimethyl sulfoxide (DMSO) solvent to dissolve the HE. An important component of the workstation is the air cleaning system that is used to contain DMSO aerosols and vapor and radioactive aerosols. The air cleaning system consists of a condenser to liquefy the hot DMSO vapor, a demister pad to remove most of the DMSO aerosols, a high efficiency particulate air (HEPA) filter to remove the remaining aerosols, an activated carbon filter to remove the DMSO vapor, and a final HEPA filter to meet the redundancy requirement for HEPA filters in radioactive applications. The demister pad is a 4{double_prime} thick mat of glass and steel fibers and was selected after conducting screening tests on promising candidates. We also conducted screening tests on various activated carbons and found that all had a similar performance. The carbon breakthrough curves were fitted to a modified Wheeler`s equation and gave excellent predictions for the effect of different flow rates. After all of the components were assembled, we ran a series of performance tests on the components and system to determine the particle capture efficiency as a function of size for dioctyl sebacate (DOS) and DMSO aerosols using laser particle counters and filter samples. The pad had an efficiency greater than 990% for 0.1 {mu}m DMSO particles. Test results on the prototype carbon filter showed only 70% efficiency, instead of the 99.9% in small scale laboratory tests. Thus further work will be required to develop the prototype carbon filter. 7 refs., 18 figs., 10 tabs.

Perspective: Maintaining surface-phase purity is key to efficient open air fabricated cuprous oxide solar cells

Energy Technology Data Exchange (ETDEWEB)

Hoye, Robert L. Z., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk; Ievskaya, Yulia; MacManus-Driscoll, Judith L., E-mail: rlzh2@cam.ac.uk, E-mail: jld35@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Brandt, Riley E.; Buonassisi, Tonio [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Heffernan, Shane [Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Musselman, Kevin P. [Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2015-02-01

Electrochemically deposited Cu{sub 2}O solar cells are receiving growing attention owing to a recent doubling in efficiency. This was enabled by the controlled chemical environment used in depositing doped ZnO layers by atomic layer deposition, which is not well suited to large-scale industrial production. While open air fabrication with atmospheric pressure spatial atomic layer deposition overcomes this limitation, we find that this approach is limited by an inability to remove the detrimental CuO layer that forms on the Cu{sub 2}O surface. Herein, we propose strategies for achieving efficiencies in atmospherically processed cells that are equivalent to the high values achieved in vacuum processed cells.

Perspective: Maintaining surface-phase purity is key to efficient open air fabricated cuprous oxide solar cells

International Nuclear Information System (INIS)

Hoye, Robert L. Z.; Ievskaya, Yulia; MacManus-Driscoll, Judith L.; Brandt, Riley E.; Buonassisi, Tonio; Heffernan, Shane; Musselman, Kevin P.

2015-01-01

Electrochemically deposited Cu 2 O solar cells are receiving growing attention owing to a recent doubling in efficiency. This was enabled by the controlled chemical environment used in depositing doped ZnO layers by atomic layer deposition, which is not well suited to large-scale industrial production. While open air fabrication with atmospheric pressure spatial atomic layer deposition overcomes this limitation, we find that this approach is limited by an inability to remove the detrimental CuO layer that forms on the Cu 2 O surface. Herein, we propose strategies for achieving efficiencies in atmospherically processed cells that are equivalent to the high values achieved in vacuum processed cells

Energy efficient piston configuration for effective air motion – A CFD study

International Nuclear Information System (INIS)

Gnana Sagaya Raj, Antony Raj; Mallikarjuna, Jawali Maharudrappa; Ganesan, Venkitachalam

2013-01-01

Highlights: ► All piston crown show similar flow pattern for experimental and simulated studies. ► Piston position plays a predominant role in the air pattern inside the cylinder. ► The flat bowl piston shows higher TKE compared to all other piston crown shape. ► The turbulence intensity and length scale are higher for flat bowl piston. ► The quantitative error between the CFD and PIV analysis is about 5%. -- Abstract: Air motion inside the cylinder is very important from the point of view of energy efficiency. In this direction, piston configuration plays a very crucial role. This study is concerned with the CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the experimental results available in the literature. Four configurations viz., flat, inclined, centre bowl and inclined offset bowl pistons have been studied. For numerical analysis STAR-CD CFD software has been used. Experimental results available in the literature for comparison are obtained by PIV measurements. From this study, it is concluded that a centre bowl on flat piston is found to be the best from the point of view of tumble ratio, turbulent kinetic energy, turbulent intensity and turbulent length scale which play very important role in imparting proper air motion, there by increasing the energy efficiency of the engine.

UNDERGROUND AIR DUCT TO CONTROL RISING MOISTURE IN HISTORIC BUILDINGS: IMPROVED DESIGN AND ITS DRYING EFFICIENCY

Directory of Open Access Journals (Sweden)

Jiří Pazderka

2017-10-01

Full Text Available The underground air ducts along peripheral walls of a building are a remediation method, which principle is to enable an air flow along the moist building structure’s surface to allow a sufficient evaporation of moisture from the structure. This measure reduces the water transport (rising moisture into the higher parts of the wall where the high water content in masonry is undesirable. Presently, underground air ducts are designed as masonry structures, which durability in contact with ground moisture is limited. The article describes a new design of an underground air duct, which is based on specially shaped concrete blocks (without wet processes, because the blocks are completely precast. The air duct from concrete blocks is situated completely below the ground surface (exterior or below the floor (interior. Thanks to this, the system is invisible and does not disturb the authentic look of rehabilitated historic buildings. The efficiency of the air duct technical solution was verified by the results of tests (based on the measured moisture values conducted on a laboratory model. The experimental study showed that the moisture in the masonry equipped with the presented underground air duct had decreased considerably compared to the reference sample, namely by 43 % on average. The experimental study was numerically validated through numerical simulations performed with the program WUFI 2D.

Indigenous high volume air sampler

International Nuclear Information System (INIS)

Kotrappa, P.; Setty, N.P.N.; Raghunath, B.; Sivasubrahmanyam, P.S.

1978-01-01

A high volume air sampler for use in assessing concentrations of low levels of air borne particulates has been fabricated. The sampler will be of use in radioactive installations, conventional industries and environmental pollution analysis. It is comparable in performance with the imported Staplex air samplers. A turbine and motor system similar to the one found in conventional vacuum cleaners is used in its design. The sampler units can be produced in large numbers. (M.G.B.)

High-Energy Electron Beam Application to Air Pollutants Removal

International Nuclear Information System (INIS)

Ighigeanu, D.; Martin, D.; Manaila, E.; Craciun, G.; Calinescu, I.

2009-01-01

The advantage of electron beam (EB) process in pollutants removal is connected to its high efficiency to transfer high amount of energy directly into the matter under treatment. Disadvantage which is mostly related to high investment cost of accelerator may be effectively overcome in future as the result of use accelerator new developments. The potential use of medium to high-energy high power EB accelerators for air pollutants removal is demonstrated in [1]. The lower electrical efficiencies of accelerators with higher energies are partially compensated by the lower electron energy losses in the beam windows. In addition, accelerators with higher electron energies can provide higher beam powers with lower beam currents [1]. The total EB energy losses (backscattering, windows and in the intervening air space) are substantially lower with higher EB incident energy. The useful EB energy is under 50% for 0.5 MeV and about 95% above 3 MeV. In view of these arguments we decided to study the application of high energy EB for air pollutants removal. Two electron beam accelerators are available for our studies: electron linear accelerators ALIN-10 and ALID-7, built in the Electron Accelerator Laboratory, INFLPR, Bucharest, Romania. Both accelerators are of traveling-wave type, operating at a wavelength of 10 cm. They utilize tunable S-band magnetrons, EEV M 5125 type, delivering 2 MW of power in 4 μ pulses. The accelerating structure is a disk-loaded tube operating in the 2 mode. The optimum values of the EB peak current IEB and EB energy EEB to produce maximum output power PEB for a fixed pulse duration EB and repetition frequency fEB are as follows: for ALIN-10: EEB = 6.23 MeV; IEB =75 mA; PEB 164 W (fEB = 100 Hz, EB = 3.5 s) and for ALID-7: EEB 5.5 MeV; IEB = 130 mA; PEB = 670 W (fEB = 250 Hz, EB = 3.75 s). This paper presents a special designed installation, named SDI-1, and several representative results obtained by high energy EB application to SO 2 , NOx and VOCs

Radiation-hard, high efficiency InP solar cell and panel development

International Nuclear Information System (INIS)

Keavney, C.J.; Vernon, S.M.; Haven, V.E.; Nowlan, M.J.; Walters, R.J.; Slatter, R.L.; Summers, G.P.

1991-01-01

Indium phosphide solar cells with efficiencies over 19% (Air mass zero, 25 degrees C) and area of 4 cm 2 have been made and incorporated into prototype panels. The panels will be tested in space to confirm the high radiation resistance expected from InP solar cells, which makes the material attractive for space use, particularly in high-radiation orbits. Laboratory testing indicated an end-of-life efficiency of 15.5% after 10 15 1 MeV electrons, and 12% after 10 16 . These cells are made by metalorganic chemical vapor deposition, and have a shallow homojunction structure. The manufacturing process is amendable to scale-up to larger volumes; more than 200 cells were produced in the laboratory operation. Cell performance, radiation degradation, annealing behavior, and results of deep level transient spectroscopy studies are presented in this paper

Energy efficiency comparison of forced-air versus resistance heating devices for perioperative hypothermia management

International Nuclear Information System (INIS)

Bayazit, Yilmaz; Sparrow, Ephraim M.

2010-01-01

Hypothermia is a state in which the temperature of a human body is below the normal temperature, with the onset of the hypothermic state commonly regarded as 36 o C. This state may be encountered due to exposure to a very cold environment in the outdoors or, surprisingly, in a hospital operating room. In the latter situation, the diminution of metabolic heat generation, coupled with moderate temperatures in the surroundings and absence of a covering over the afflicted parts of the body, creates the possibility of hypothermia. There are several available devices that are designed to ward off the onset of hypothermia. These currently most frequently used devices can be placed in two categories: (a) convective air warming and (b) direct-contact heat conduction. The warming principles that underlie these two approaches are distinctly different. Furthermore, the energy efficiencies of the two approaches differ significantly. The energy penalty which results from these different efficiencies may be compounded by the fact that the portion of the input energies to these devices which escapes into the operating room ambient must be extracted to maintain a comfortable temperature for the surgical staff. Since energy-extracting equipments such as air-conditioning machines are far from being perfectly efficient, the heat-extraction process also introduces wasted energy. Experiments were performed to determine the energy-utilization efficiencies of the representative devices in the two categories cited above. This information, taken together with the known efficiencies of air-conditioning machines, enabled an overall efficiency encompassing both the therapeutic device and the heat-extraction device to be calculated. The experimental data revealed that the specifics of individual devices within a category played a larger role with regard to energy efficiency than did the category itself.

Energy efficiency comparison of forced-air versus resistance heating devices for perioperative hypothermia management

Energy Technology Data Exchange (ETDEWEB)

Bayazit, Yilmaz; Sparrow, Ephraim M. [Laboratory for Heat Transfer and Fluid Flow Practice, Department of Mechanical Engineering, University of Minnesota, 111 Church Street, SE, Minneapolis, MN 55455-0111 (United States)

2010-03-15

Hypothermia is a state in which the temperature of a human body is below the normal temperature, with the onset of the hypothermic state commonly regarded as 36 C. This state may be encountered due to exposure to a very cold environment in the outdoors or, surprisingly, in a hospital operating room. In the latter situation, the diminution of metabolic heat generation, coupled with moderate temperatures in the surroundings and absence of a covering over the afflicted parts of the body, creates the possibility of hypothermia. There are several available devices that are designed to ward off the onset of hypothermia. These currently most frequently used devices can be placed in two categories: (a) convective air warming and (b) direct-contact heat conduction. The warming principles that underlie these two approaches are distinctly different. Furthermore, the energy efficiencies of the two approaches differ significantly. The energy penalty which results from these different efficiencies may be compounded by the fact that the portion of the input energies to these devices which escapes into the operating room ambient must be extracted to maintain a comfortable temperature for the surgical staff. Since energy-extracting equipments such as air-conditioning machines are far from being perfectly efficient, the heat-extraction process also introduces wasted energy. Experiments were performed to determine the energy-utilization efficiencies of the representative devices in the two categories cited above. This information, taken together with the known efficiencies of air-conditioning machines, enabled an overall efficiency encompassing both the therapeutic device and the heat-extraction device to be calculated. The experimental data revealed that the specifics of individual devices within a category played a larger role with regard to energy efficiency than did the category itself. (author)

Study on residential appliances energy efficiency standards Refrigerators, air-conditioners, incandescent lamps, fluorescent lamps, color TVs

Energy Technology Data Exchange (ETDEWEB)

Lee, S.G.; Cho, S.K.; Choi, S.H.; Jung, B.M.; Han, S.B.; Kim, K.D. [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

1995-12-01

The energy efficiency standards and rating act, as amended by the rational energy utilization act, provides energy efficiency standards and ratings for 6 types of consumer products(refrigerators, air-conditioners, fluorescent lamps, incandescent lamps, ballasts and cars) authorizes the Ministry of Trade, Industry and Energy(MOTIE) to prescribe amended or new energy efficiency standards and rating standards. This study was initiated by the KIER in 1992. KIER`s assessment of the standards is designed to evaluate their statistical and engineering analysis according to Korean(Industrial) Standards(KS). And to make distinction between the poor efficiency and good efficiency models, 5 grades are classified depending on their tested energy efficiency. This year, based on our analysis, MOTIE mandated updated standards for refrigerators, air-conditioners, incandescent lamps, and fluorescent lamps. Also the objective of this study is to set the energy efficiency standards and to grade for color TV sets. (author). 37 refs., 89 figs., 85 tabs.

Energy-Efficiency and Air-Pollutant Emissions-Reduction Opportunities for the Ammonia Industry in China

Energy Technology Data Exchange (ETDEWEB)

Ma, Ding [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hasanbeigi, Ali [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chen, Wenying [Tsinghua Univ., Beijing (China)

2015-06-01

As one of the most energy-intensive and polluting industries, ammonia production is responsible for significant carbon dioxide (CO₂) and air-pollutant emissions. Although many energy-efficiency measures have been proposed by the Chinese government to mitigate greenhouse gas emissions and improve air quality, lack of understanding of the cost-effectiveness of such improvements has been a barrier to implementing these measures. Assessing the costs, benefits, and cost-effectiveness of different energy-efficiency measures is essential to advancing this understanding. In this study, a bottom-up energy conservation supply curve model is developed to estimate the potential for energy savings and emissions reductions from 26 energy-efficiency measures that could be applied in China’s ammonia industry. Cost-effective implementation of these measures saves a potential 271.5 petajoules/year for fuel and 5,443 gigawatt-hours/year for electricity, equal to 14% of fuel and 14% of electricity consumed in China’s ammonia industry in 2012. These reductions could mitigate 26.7 million tonnes of CO₂ emissions. This study also quantifies the co-benefits of reducing air-pollutant emissions and water use that would result from saving energy in China’s ammonia industry. This quantitative analysis advances our understanding of the cost-effectiveness of energy-efficiency measures and can be used to augment efforts to reduce energy use and environmental impacts.

Highly efficient indoor air purification using adsorption-enhanced-photocatalysis-based microporous TiO2 at short residence time.

Science.gov (United States)

Lv, Jinze; Zhu, Lizhong

2013-01-01

A short residence time is a key design parameter for the removal of organic pollutants in catalyst-based indoor air purification systems. In this study, we synthesized a series of TiO2 with different micropore volumes and studied their removal efficiency of indoor carbonyl pollutants at a short residence time. Our results indicated that the superior adsorption capability of TiO2 with micropores improved its performance in the photocatalytic degradation of cyclohexanone, while the photocatalytic removal of the pollutant successfully kept porous TiO2 from becoming saturated. When treated with 1 mg m(-3) cyclohexanone at a relatively humidity of 18%, the adsorption amount on microporous TiO2 was 5.4-7.9 times higher than that on P25. Removal efficiency via photocatalysis followed'the same order as the adsorption amount: TiO2-5 > TiO2-20 > TiO2-60 > TiO2-180 > P25. The advantage of microporous TiO2 over P25 became more pronounced when the residence time declined from 0.072 to 0.036 s. Moreover, as the concentration of cyclohexanone deceased from 1000 ppb to 500 ppb, removal efficiency by microporous TiO2 increased more rapidly than P25.

Second Generation Advanced Reburning for High Efficiency NOx Control

International Nuclear Information System (INIS)

Zamansky, Vladimir M.; Maly, Peter M.; Sheldon, Mark; Seeker, W. Randall; Folsom, Blair A.

1997-01-01

Energy and Environmental Research Corporation is developing a family of high efficiency and low cost NO x control technologies for coal fired utility boilers based on Advanced Reburning (AR), a synergistic integration of basic reburning with injection of an N-agent. In conventional AR, injection of the reburn fuel is followed by simultaneous N-agent and overfire air injection. The second generation AR systems incorporate several components which can be used in different combinations. These components include: (1) Reburning Injection of the reburn fuel and overfire air. (2) N-agent Injection The N-agent (ammonia or urea) can be injected at different locations: into the reburning zone, along with the overfire air, and downstream of the overfire air injection. (3) N-agent Promotion Several sodium compounds can considerably enhance the NO x control from N-agent injection. These ''promoters'' can be added to aqueous N-agents. (4) Two Stages of N-agent Injection and Promotion Two N-agents with or without promoters can be injected at different locations for deeper NO x control. AR systems are intended for post-RACT applications in ozone non-attainment areas where NO x control in excess of 80% is required. AR will provide flexible installations that allow NO x levels to be lowered when regulations become more stringent. The total cost of NO x control for AR systems is approximately half of that for SCR. Experimental and kinetic modeling results for development of these novel AR systems are presented. Tests have been conducted in a 1.0 MMBtu/hr Boiler Simulator Facility with coal as the main fuel and natural gas as the reburning fuel. The results show that high efficiency NO x control, in the range 84-95%, can be achieved with various elements of AR. A comparative byproduct emission study was performed to compare the emissions from different variants of AR with commercial technologies (reburning and SNCR). For each technology sampling included: CO, SO 2 , N 2 O, total

Viral Penetration of High Efficiency Particulate Air (HEPA) Filters (PREPRINT)

Science.gov (United States)

2009-09-01

US Plastics, Lima , 155 Ohio). Each path runs through a test article and thence through one AGI-30 all-glass 156 impinger (Chemglass, Vineland, N.J...rotameter (Blue–White 400, Huntington Beach , California, or PMR1-159 101346, Cole–Parmer, Vernon Hills, Illinois). At the end of the sampling path...fibrous Filters." J. Air Pollution Control Assoc. 30 [4]: 501 377–381. 502 Leenders, G.J.M, A.C. Bolle, and J. Stadhouders. 1984. “A Study of the

China Energy Efficiency Round Robin Testing Results for Room Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Zhou, Nan; Fridley, David; Zheng, Nina; Pierrot, Andre

2010-06-07

consuming products has always been an important component of all countries energy strategies. As we all know, a very large amount of total energy consumption is due to energy consuming products and equipment, which account for about 50% of China's total energy consumption. However, the current average energy utilization efficiency of this sector is only about 60%, 10 percent lower than the international advanced level. Therefore, China's energy consuming products and equipment sector holds great energy-saving potential. On the other hand, the energy supplied to these products is mainly from fossil fuel combustion, a major source of greenhouse gas (GHG) emissions. Therefore, improving the energy efficiency and augmenting the market share of market-dominant energy consuming products is of significant importance to achieving China's energy saving and emission reduction target and is an effective means to deal with energy and environmental constraints and climate change issues. Main energy consuming products generally include widely-used home appliances, industrial equipment, office equipment, transportation vehicles, etc. China is one of the major manufacturers and exporters of energy end-using products such as air-conditioners, refrigerators, televisions, etc. Their overall energy efficiency is comparatively low and the products are poorly designed, leading to great energy-saving potential. For example, electricity consumption of air conditioners accounts for about 20% of China's total electricity consumption and 40% of the summer electricity peak load in large and medium cities. However, less than 5% of units sold in the domestic market in 2009 reached the standard's highly efficient level of grade 2 above. The electricity consumption of electric motors and their related drive systems accounts for about 60% of China's total electricity consumption; however, less than 2% of the domestic market share consists of energy-efficient electric motor

Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

International Nuclear Information System (INIS)

Guangul, F M; Sulaiman, S A; Ramli, A

2013-01-01

Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

Evaluating co-benefits of energy efficiency and air pollution abatement in China’s cement industry

NARCIS (Netherlands)

Zhang, Shaohui; Worrell, Ernst; Crijns - Graus, Wina

2015-01-01

China’s cement industry is the world’s largest and is one of the largest energy consuming, and GHG and air pollutant emitting industries. Actions to improve energy efficiency by best available technology can often bring co-benefits for climate change and air quality through reducing emissions of

A MultiAir®/MultiFuel Approach to Enhancing Engine System Efficiency

Energy Technology Data Exchange (ETDEWEB)

Reese, Ronald [Chrysler Group LLC., Auburn Hills, MI (United States)

2015-05-20

FCA US LLC (formally known as Chrysler Group LLC, and hereinafter “Chrysler”) was awarded an American Recovery and Reinvestment Act (ARRA) funded project by the Department of Energy (DOE) titled “A MultiAir®/MultiFuel Approach to Enhancing Engine System Efficiency” (hereinafter “project”). This award was issued after Chrysler submitted a proposal for Funding Opportunity Announcement DE-FOA- 0000079, “Systems Level Technology Development, Integration, and Demonstration for Efficient Class 8 Trucks (SuperTruck) and Advanced Technology Powertrains for Light-Duty Vehicles (ATP-LD).” Chrysler started work on this project on June 01, 2010 and completed testing activities on August 30, 2014. Overall objectives of this project were; Demonstrate a 25% improvement in combined Federal Test Procedure (FTP) City and Highway fuel economy over a 2009 Chrysler minivan; Accelerate the development of highly efficient engine and powertrain systems for light-duty vehicles, while meeting future emissions standards; and Create and retain jobs in accordance with the American Recovery and Reinvestment Act of 2009

Thermal performance of an open thermosyphon using nanofluid for evacuated tubular high temperature air solar collector

International Nuclear Information System (INIS)

Liu, Zhen-Hua; Hu, Ren-Lin; Lu, Lin; Zhao, Feng; Xiao, Hong-shen

2013-01-01

Highlights: • A novel solar air collector with simplified CPC and open thermosyphon is designed and tested. • Simplified CPC has a much lower cost at the expense of slight efficiency loss. • Nanofluid effectively improves thermal performance of the above solar air collector. • Solar air collector with open thermosyphon is better than that with concentric tube. - Abstract: A novel evacuated tubular solar air collector integrated with simplified CPC (compound parabolic concentrator) and special open thermosyphon using water based CuO nanofluid as the working fluid is designed to provide air with high and moderate temperature. The experimental system has two linked panels and each panel includes an evacuated tube, a simplified CPC and an open thermosyphon. Outdoor experimental study has been carried out to investigate the actual solar collecting performance of the designed system. Experimental results show that air outlet temperature and system collecting efficiency of the solar air collector using nanofluid as the open thermosyphon’s working fluid are both higher than that using water. Its maximum air outlet temperature exceeds 170 °C at the air volume rate of 7.6 m 3 /h in winter, even though the experimental system consists of only two collecting panels. The solar collecting performance of the solar collector integrated with open thermosyphon is also compared with that integrated with common concentric tube. Experimental results show that the solar collector integrated with open thermosyphon has a much better collecting performance

Technologies for high performance and energy saving in room air conditioners. Shoenegata kokoritsu eakon ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kawai, N. (Toshiba Corp., Tokyo (Japan))

1994-05-31

An energy saving inverter type air-conditioner was introduced. It is important to increase the efficiency in the low capacity zone below the rated capacity to realize the energy saving. For the reduction of peak, improving the efficiency in the high capacity operation is also necessary. The power consumption in compressor and in inverter is about 90 % of the total power consumption in air-conditioner. The other 10 % are distributed to the fan motor and the control unit. For achieving the energy saving, the reduction of this 10 % part is also necessary because this 10 % part is constant regardless of the capacity of air-conditioner. The compressor motor was modified to the brushless DC motor with rotor position detecting device to improve the rotor structure and the position detection system. The heat exchanger was changed to a room heat exchanger with slit pattern. For the outdoor heat exchanger, the complex curvature blade fan was adopted. The control system of air-conditioner was changed. The PMV was previously learned and input in the microcomputer to calculate the data. Resultantly, the power consumption was reduced by about 20 % as compared with the conventional air-conditioner. 10 figs., 1 tab.

Proposals to enhance thermal efficiency programs and air pollution control in south-central Chile

International Nuclear Information System (INIS)

Schueftan, Alejandra; González, Alejandro D.

2015-01-01

Major cities in South-central Chile suffer high levels of particulate matter PM 10 and PM 2.5 due to combustion of solid fuels for heating. Exposure to these air pollutants is recognized as a major contribution to ill health in the region. Here we discuss new strategies to reduce air pollution. Regulations and subsidies focusing on improved combustion by providing drier wood fuel and better stoves have been in effect since 2007. However, air pollution due to combustion of wood fuel has been steadily rising, along with reports on health consequences. The paper analyzes a survey of 2025 households in the city of Valdivia, which found that wood fuel quality, stove renewal, and awareness of programs are strongly affected by income level, and that higher consumption of wood fuel is found in households already having better stoves and drier wood fuel. The analysis suggests that regulations intended to improve combustion are influenced by user's behavior and have limited potential for lowering pollution. We conclude that thermal refurbishment has a larger potential for improvement, not yet been implemented as an energy policy for the majority. Here we propose improvements and additions to current programs to enhance effectiveness and cover the whole social spectrum. - Highlights: • High levels of PM 2.5 from wood combustion affect cities of south-central Chile. • Current programs on dry wood fuel and stoves renewal have not reduced air pollution. • Real operation of wood stoves strongly depends on user's behavior. • Buildings' energy efficiency has greater potential for reducing emissions. • Retrofit prevents degradation of native forest and improves indoor temperature

Consumer life-cycle cost impacts of energy-efficiency standards for residential-type central air conditioners and heat pumps

International Nuclear Information System (INIS)

Rosenquist, Gregory; Chan, Peter; Lekov, Alex; McMahon, James; Van Buskirk, Robert

2001-01-01

In support of the federal government's efforts to raise the minimum energy-efficiency standards for residential-type central air conditioners and heat pumps, a consumer life-cycle cost (LCC) analysis was conducted to demonstrate the economic impacts on individual consumers from revisions to the standards. LCC is the consumer's cost of purchasing and installing an air conditioner or heat pump and operating the unit over its lifetime. The LCC analysis is conducted on a nationally representative sample of air conditioner and heat pump consumers resulting in a distribution of LCC impacts showing the percentage of consumers that are either benefiting or being burdened by increased standards. Relative to the existing minimum efficiency standard of 10 SEER, the results show that a majority of split system air conditioner and heat pump consumers will either benefit or be insignificantly impacted by increased efficiency standards of up to 13 SEER

Consumer life-cycle cost impacts of energy-efficiency standards for residential-type central air conditioners and heat pumps

Energy Technology Data Exchange (ETDEWEB)

Rosenquist, Gregory; Chan, Peter; Lekov, Alex; McMahon, James; Van Buskirk, Robert

2001-10-10

In support of the federal government's efforts to raise the minimum energy-efficiency standards for residential-type central air conditioners and heat pumps, a consumer life-cycle cost (LCC) analysis was conducted to demonstrate the economic impacts on individual consumers from revisions to the standards. LCC is the consumer's cost of purchasing and installing an air conditioner or heat pump and operating the unit over its lifetime. The LCC analysis is conducted on a nationally representative sample of air conditioner and heat pump consumers resulting in a distribution of LCC impacts showing the percentage of consumers that are either benefiting or being burdened by increased standards. Relative to the existing minimum efficiency standard of 10 SEER, the results show that a majority of split system air conditioner and heat pump consumers will either benefit or be insignificantly impacted by increased efficiency standards of up to 13 SEER.

Fabrication of 3D Air-core MEMS Inductors for High Frequency Power Electronic Applications

DEFF Research Database (Denmark)

Lê Thanh, Hoà; Mizushima, Io; Nour, Yasser

2018-01-01

footprints have an inductance from 34.2 to 44.6 nH and a quality factor from 10 to 13 at frequencies ranging from 30 to 72 MHz. The air-core inductors show threefold lower parasitic capacitance and up to a 140% higher-quality factor and a 230% higher-operation frequency than silicon-core inductors. A 33 MHz...... boost converter mounted with an air-core toroidal inductor achieves an efficiency of 68.2%, which is better than converters mounted with a Si-core inductor (64.1%). Our inductors show good thermal cycling stability, and they are mechanically stable after vibration and 2-m-drop tests.......We report a fabrication technology for 3D air-core inductors for small footprint and very-high-frequency power conversions. Our process is scalable and highly generic for fabricating inductors with a wide range of geometries and core shapes. We demonstrate spiral, solenoid, and toroidal inductors...

Polymer Separators for High-Power, High-Efficiency Microbial Fuel Cells

KAUST Repository

Chen, Guang

2012-12-26

Microbial fuel cells (MFCs) with hydrophilic poly(vinyl alcohol) (PVA) separators showed higher Coulombic efficiencies (94%) and power densities (1220 mW m-2) than cells with porous glass fiber separators or reactors without a separator after 32 days of operation. These remarkable increases in both the coublomic efficiency and the power production of the microbial fuel cells were made possible by the separator\\'s unique characteristics of fouling mitigation of the air cathode without a large increase in ionic resistance in the cell. This new type of polymer gel-like separator design will be useful for improving MFC reactor performance by enabling compact cell designs. © 2012 American Chemical Society.

Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

International Nuclear Information System (INIS)

Gupta, A.; Biswas, P.; Monson, P.R.; Novick, V.J.

1993-01-01

The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K 2 was computed for different test conditions and used as a measure of the mass loading capacity. K 2 was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K 2 for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs

Highly efficient removal of arsenic metal ions with high superficial area hollow magnetite nanoparticles synthetized by AACVD method

Energy Technology Data Exchange (ETDEWEB)

Monárrez-Cordero, B.; Amézaga-Madrid, P.; Antúnez-Flores, W.; Leyva-Porras, C.; Pizá-Ruiz, P. [Centro de Investigación en Materiales Avanzados S.C., and Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, Chihuahua, Chih. C.P. 31109 (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigación en Materiales Avanzados S.C., and Laboratorio Nacional de Nanotecnología, Miguel de Cervantes 120, Chihuahua, Chih. C.P. 31109 (Mexico)

2014-02-15

Highlights: ► Fast and high arsenic removal efficiency, almost 100% in one minute. ► Successful synthesis of high purity magnetite hollow nanoparticles is reported. ► They were synthesized by one step aerosol assisted CVD technique. ► Detailed microstructural characterization by electron microscopy was performed. -- Abstract: New nanotechnology alternatives and methodologies have been developed in order to overcome the limitations of conventional techniques for metal ions removal from water. Currently, the removal of heavy metals requires multiple steps which include the separation and post-treatment of the generated sludge. Usually, this sludge is composed of dangerous environmental pollutants mixed with the material used for removing the metal ion. Thus, the removal of these metals becomes a challenging task. Herein we report the synthesis of magnetite nanoparticles with high specific area by the aerosol assisted chemical vapour deposition method. Deposition temperature were fixed at 450 °C and a mixture of Ar–air were used as a carrier gas, a flow of 1.0 and 0.015 L min{sup −1} were used for Ar and air, respectively. The precursor solution was a dilution of Fe (II) chloride in methanol, with different concentration 0.01, 0.05 and 0.1 mol dm{sup −3}. The crystalline structure of the nanoparticles was characterized by grazing incidence X-ray diffraction. Morphology and microstructure were analyzed by field emission scanning electron microscopy, scanning probe microscopy and transmission electron microscopy. Magnetic properties were evaluated with a vibrating sample magnetometer and specific area was measured by the Brunauer–Emmett–Teller method. To determine the removal efficiency of arsenic ion from water, several tests were carried out at six exposition times 1, 3, 5, 10, 20 and 30 min. Results showed high removal efficiency, more than 99%, in less than 1 min.

Behavior of highly radioactive iodine on charcoal in moist air

International Nuclear Information System (INIS)

Lorenz, R.A.; Manning, S.R.; Martin, W.J.

1976-01-01

The behavior of highly radioactive iodine adsorbed on charcoal exposed to moist air (110 torr water vapor partial pressure) was investigated in a series of six experiments. The amount of radioactive 130 I on the well-insulated 28-cm 3 bed ranged from 50 to 570 Ci, and the relative humidity was 47 percent at the bed inlet temperature of 70 0 C. Radioactive iodine was released from the test beds at a continuous fractional release rate of approximately 7 x 10 -6 /hr for all types of charcoal tested. The chemical form of the released iodine was such that it was very highly penetrating with respect to the nine different types of commercial impregnated charcoals tested in backup collection beds. Two types of silver-nitrate-coated adsorption materials behaved similarly to the charcoals. Silver-exchanged type 13-X molecular sieve adsorbers were 20 to 50 times more efficient for adsorbing the highly penetrating iodine, but not as efficient as normally found for collecting methyl iodide. The chemical form of the highly penetrating iodine was not determined. When the moist air velocity was decreased from 28.5 fpm (25 0 C) to as low as 0.71 fpm (25 0 C), the charcoal bed temperature rose slowly and reached the ignition temperature in three of the experiments. At 0.71 fpm (25 0 C) the ignited charcoal beds reached maximum temperatures of 430 to 470 0 C because of the limited oxygen supply. The charcoal exposed for four years at Oak Ridge ignited at 283 0 C compared with 368 0 C for unused charcoal from the same batch. Two of the experiments used charcoal containing 1 or 2 percent TEDA (triethylene-diamine) and a proprietary flame retardant. The oxidation and ignition behavior of these charcoals did not appear to be affected adversely by the presence of the TEDA

Efficient and Highly Aldehyde Selective Wacker Oxidation

KAUST Repository

Teo, Peili; Wickens, Zachary K.; Dong, Guangbin; Grubbs, Robert H.

2012-01-01

A method for efficient and aldehyde-selective Wacker oxidation of aryl-substituted olefins using PdCl 2(MeCN) 2, 1,4-benzoquinone, and t-BuOH in air is described. Up to a 96% yield of aldehyde can be obtained, and up to 99% selectivity can be achieved with styrene-related substrates. © 2012 American Chemical Society.

Efficient and Highly Aldehyde Selective Wacker Oxidation

KAUST Repository

Teo, Peili

2012-07-06

A method for efficient and aldehyde-selective Wacker oxidation of aryl-substituted olefins using PdCl 2(MeCN) 2, 1,4-benzoquinone, and t-BuOH in air is described. Up to a 96% yield of aldehyde can be obtained, and up to 99% selectivity can be achieved with styrene-related substrates. © 2012 American Chemical Society.

Effect of secondary air injection on the combustion efficiency of sawdust in a fluidized bed combustor

Directory of Open Access Journals (Sweden)

K. V. N. Srinivasa Rao

2008-03-01

Full Text Available Agricultural wastes like bagasse, paddy husks, sawdust and groundnut shells can be effectively used as fuels for fluidized bed combustion; otherwise these biomass fuels are difficult to handle due to high moisture and fines content. In the present work the possibility of using sawdust in the fluidized bed combustor, related combustion efficiencies and problems encountered in the combustion process are discussed. The temperature profiles for sawdust with an increase in fluidizing velocity along the vertical height above the distributor plate indicate that considerable burning of fuel particles is taking place in the freeboard zone rather than complete burning within the bed. Therefore, an enlarged disengagement section is provided to improve the combustion of fines. The temperature profiles along the bed height are observed at different feed rates. The feed rate of sawdust corresponding to the maximum possible temperature was observed to be 10.2 kg/h. It is observed that 50-60% excess air is optimal for reducing carbon loss during the burning of sawdust. The maximum possible combustion efficiency with sawdust is 99.2% and is observed with 65% excess air.

Air traffic energy efficiency differs from place to place: analysis of historical trends by geographical zones using a macro-level methodology

International Nuclear Information System (INIS)

Cheze, Benoit; Gastineau, Pascal; Chevallier, Julien

2011-01-01

This article analyses energy efficiency coefficients and their evolution in the air transport sector. The proposed 'macro-level' methodology allows obtaining energy efficiency coefficients and their growth rates (corresponding to the evolution of energy gains) from 1983 to 2006 for eight distinct geographical regions and at the world level. During the whole period, energy efficiency improvements have been equal to 2.88% per year at the world level, with strong differences between regions. Moreover, our results indicate that domestic air travels are less energy efficient (i.e. more carbon intensive) than international air travels. This result applies in all regions. (authors)

Experimental determination of the energy efficiency of an air-cooled chiller under part load conditions

International Nuclear Information System (INIS)

Yu, F.W.; Chan, K.T.

2005-01-01

In cities located in a subtropical climate, air-cooled chillers are commonly used to provide cooling to the indoor environment. This accounts for the increasing electricity demand of buildings over the decades. This paper investigates how the condensing temperature serves to accurately determine the energy efficiency, or coefficient of performance (COP), of air-cooled chillers under part load conditions. An experiment on an air-cooled reciprocating chiller showed that for any given operating condition, the COP of the chiller varies, depending on how the condensing temperature is controlled. A sensitivity analysis is implemented to investigate to what extent COP is responding to changes in operating variables and confirms that the condensing temperature is an adequate variable to gauge COP under various operating conditions. The specifications of the upper limit for the condensing temperature in order to improve the energy efficiency of air-cooled chillers are discussed. The results of this work will give designers and researchers a good idea about how to model chiller energy performance curves in the thermal and energy computation exercises

Technology Roadmap: High-Efficiency, Low-Emissions Coal-Fired Power Generation

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

Coal is the largest source of power globally and, given its wide availability and relatively low cost, it is likely to remain so for the foreseeable future. The High-Efficiency, Low-Emissions Coal-Fired Power Generation Roadmap describes the steps necessary to adopt and further develop technologies to improve the efficiency of the global fleet of coal. To generate the same amount of electricity, a more efficient coal-fired unit will burn less fuel, emit less carbon, release less local air pollutants, consume less water and have a smaller footprint. High-efficiency, low emissions (HELE) technologies in operation already reach a thermal efficiency of 45%, and technologies in development promise even higher values. This compares with a global average efficiency for today’s fleet of coal-fired plants of 33%, where three-quarters of operating units use less efficient technologies and more than half is over 25 years old. A successful outcome to ongoing RD&D could see units with efficiencies approaching 50% or even higher demonstrated within the next decade. Generation from older, less efficient technology must gradually be phased out. Technologies exist to make coal-fired power generation much more effective and cleaner burning. Of course, while increased efficiency has a major role to play in reducing emissions, particularly over the next 10 years, carbon capture and storage (CCS) will be essential in the longer term to make the deep cuts in carbon emissions required for a low-carbon future. Combined with CCS, HELE technologies can cut CO2 emissions from coal-fired power generation plants by as much as 90%, to less than 100 grams per kilowatt-hour. HELE technologies will be an influential factor in the deployment of CCS. For the same power output, a higher efficiency coal plant will require less CO2 to be captured; this means a smaller, less costly capture plant; lower operating costs; and less CO2 to be transported and stored.

Dynamics of electricity efficiency in commercial air-distribution systems in Sweden

Energy Technology Data Exchange (ETDEWEB)

Christiansson, Lena

1996-04-01

This paper illustrates the long-term potential for reducing future electricity demand for air-distribution in commercial buildings in Sweden. The objective has been to develop a general quantitative scenario-based framework to describe some possible paths for electricity demand for air distribution and to analyze how governmental and utility-sponsored policy measures can affect electricity demand. The focus is on improved electricity efficiency, i.e. a reduction of electricity demand for the same level of services. The results suggest that higher electricity prices will not be very effective in reducing electricity demand, whereas significant electricity savings can be reached by implementing various policy programs, particularly standards. 56 refs, 4 figs, 5 tabs

MO-Co@N-Doped Carbon (M = Zn or Co): Vital Roles of Inactive Zn and Highly Efficient Activity toward Oxygen Reduction/Evolution Reactions for Rechargeable Zn-Air Battery

Energy Technology Data Exchange (ETDEWEB)

Chen, Biaohua [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; He, Xiaobo [Changzhou Institute of Advanced Materials, Beijing University of Chemical Technology, Changzhou 213164 P. R. China; Yin, Fengxiang [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Changzhou Institute of Advanced Materials, Beijing University of Chemical Technology, Changzhou 213164 P. R. China; Wang, Hao [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Beijing Key Laboratory of Energy Environmental Catalysis, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Liu, Di-Jia [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne IL 60439 USA; Shi, Ruixing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Chen, Jinnan [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China; Yin, Hongwei [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 P. R. China

2017-06-14

A highly efficient bifunctional oxygen catalyst is required for practical applications of fuel cells and metal-air batteries, as oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are their core electrode reactions. Here, the MO-Co@ N-doped carbon (NC, M = Zn or Co) is developed as a highly active ORR/OER bifunctional catalyst via pyrolysis of a bimetal metal-organic framework containing Zn and Co, i.e., precursor (CoZn). The vital roles of inactive Zn in developing highly active bifunctional oxygen catalysts are unraveled. When the precursors include Zn, the surface contents of pyridinic N for ORR and the surface contents of Co-N-x and Co3+/Co2+ ratios for OER are enhanced, while the high specific surface areas, high porosity, and high electrochemical active surface areas are also achieved. Furthermore, the synergistic effects between Zn-based and Co-based species can promote the well growth of multiwalled carbon nanotubes (MWCNTs) at high pyrolysis temperatures (>= 700 degrees C), which is favorable for charge transfer. The optimized CoZn-NC-700 shows the highly bifunctional ORR/OER activity and the excellent durability during the ORR/OER processes, even better than 20 wt% Pt/C (for ORR) and IrO2 (for OER). CoZn-NC-700 also exhibits the prominent Zn-air battery performance and even outperforms the mixture of 20 wt% Pt/C and IrO2.

Air pollution policies in Europe: efficiency gains from integrating climate effects with damage costs to health and crops

International Nuclear Information System (INIS)

Tollefsen, Petter; Rypdal, Kristin; Torvanger, Asbjorn; Rive, Nathan

2009-01-01

Emissions of air pollutants cause damage to health and crops, but several air pollutants also have an effect on climate through radiative forcing. We investigate efficiency gains achieved by integrating climate impacts of air pollutants into air quality strategies for the EU region. The pollutants included in this study are SO 2 , NH 3 , VOC, CO, NO x , black carbon, organic carbon, PM 2.5 , and CH 4 . We illustrate the relative importance of climate change effects compared to damage to health and crops, as well as monetary gains of including climate change contributions. The analysis considers marginal abatement costs and compares air quality and climate damage in Euros. We optimize abatement policies with respect to both climate and health impacts, which imply implementing all measures that yield a net benefit. The efficiency gains of the integrated policy are in the order of 2.5 billion Euros, compared to optimal abatement based on health and crop damage only, justifying increased abatement efforts of close to 50%. Climate effect of methane is the single most important factor. If climate change is considered on a 20- instead of a 100-year time-scale, the efficiency gain almost doubles. Our results indicate that air pollution policies should be supplemented with climate damage considerations.

Design of a Hydraulic Motor System Driven by Compressed Air

OpenAIRE

Shaw, Dein; Yu, Jyun-Jhe; Chieh, Cheng

2013-01-01

This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is transformed by a hydraulic motor to mechanical energy to enhance the efficiency of using air power....

Overview of Ecological Agriculture with High Efficiency

OpenAIRE

Huang, Guo-qin; Zhao, Qi-guo; Gong, Shao-lin; Shi, Qing-hua

2012-01-01

From the presentation, connotation, characteristics, principles, pattern, and technologies of ecological agriculture with high efficiency, we conduct comprehensive and systematic analysis and discussion of the theoretical and practical progress of ecological agriculture with high efficiency. (i) Ecological agriculture with high efficiency was first advanced in China in 1991. (ii) Ecological agriculture with high efficiency highlights "high efficiency", "ecology", and "combination". (iii) Ecol...

Modeling energy efficiency to improve air quality and health effects of China’s cement industry

International Nuclear Information System (INIS)

Zhang, Shaohui; Worrell, Ernst; Crijns-Graus, Wina; Krol, Maarten; Bruine, Marco de; Geng, Guangpo; Wagner, Fabian; Cofala, Janusz

2016-01-01

Highlights: • An integrated model was used to model the co-benefits for China’s cement industry. • PM_2_._5 would decrease by 2–4% by 2030 through improved energy efficiency. • 10,000 premature deaths would be avoided per year relative to the baseline scenario. • Total benefits are about two times higher than the energy efficiency costs. - Abstract: Actions to reduce the combustion of fossil fuels often decrease GHG emissions as well as air pollutants and bring multiple benefits for improvement of energy efficiency, climate change, and air quality associated with human health benefits. The China’s cement industry is the second largest energy consumer and key emitter of CO_2 and air pollutants, which accounts for 7% of China’s total energy consumption, 15% of CO_2, and 14% of PM_2_._5, respectively. In this study, a state-of-the art modeling framework is developed that comprises a number of different methods and tools within the same platform (i.e. provincial energy conservation supply curves, the Greenhouse Gases and Air Pollution Interactions and Synergies, ArcGIS, the global chemistry Transport Model, version 5, and Health Impact Assessment) to assess the potential for energy savings and emission mitigation of CO_2 and PM_2_._5, as well as the health impacts of pollution arising from China’s cement industry. The results show significant heterogeneity across provinces in terms of the potential for PM_2_._5 emission reduction and PM_2_._5 concentration, as well as health impacts caused by PM_2_._5. Implementation of selected energy efficiency measures would decrease total PM_2_._5 emissions by 2% (range: 1–4%) in 2020 and 4% (range: 2–8%) by 2030, compared to the baseline scenario. The reduction potential of provincial annual PM_2_._5 concentrations range from 0.03% to 2.21% by 2030 respectively, when compared to the baseline scenario. 10,000 premature deaths are avoided by 2020 and 2030 respectively relative to baseline scenario. The

Field test of radioactive high efficiency filter and filter exchange techniques of fuel cycle examination facility

International Nuclear Information System (INIS)

Hwang, Yong Hwa; Lee, Hyung Kwon; Chun, Young Bum; Park, Dae Gyu; Ahn, Sang Bok; Chu, Yong Sun; Kim, Eun Ka.

1997-12-01

The development of high efficiency filter was started to protect human beings from the contamination of radioactive particles, toxic gases and bacillus, and its gradual performance increment led to the fabrication of Ultra Low Penetration Air Filter (ULPA) today. The application field of ULPA has been spread not only to the air conditioning of nuclear power facilities, semiconductor industries, life science, optics, medical care and general facilities but also to the core of ultra-precision facilities. Periodic performance test on the filters is essential to extend its life-time through effective maintenance. Especially, the bank test on HEPA filter of nuclear facilities handling radioactive materials is required for environmental safety. Nowadays, the bank test technology has been reached to the utilization of a minimized portable detecting instruments and the evaluation techniques can provide high confidence in the area of particle distribution and leakage test efficiency. (author). 16 refs., 13 tabs., 14 figs

Surpassing 10% Efficiency Benchmark for Nonfullerene Organic Solar Cells by Scalable Coating in Air from Single Nonhalogenated Solvent

Energy Technology Data Exchange (ETDEWEB)

Ye, Long [Department of Physics, Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh NC 27695 USA; Xiong, Yuan [Department of Physics, Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh NC 27695 USA; Zhang, Qianqian [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill NC 27599 USA; Li, Sunsun [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Wang, Cheng [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Jiang, Zhang [Advanced Photon Source, Argonne National Laboratory, Argonne IL 60439 USA; Hou, Jianhui [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; You, Wei [Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill NC 27599 USA; Ade, Harald [Department of Physics, Organic and Carbon Electronics Lab (ORaCEL), North Carolina State University, Raleigh NC 27695 USA

2018-01-10

The commercialization of nonfullerene organic solar cells (OSCs) relies critically on the response under typical operating conditions (for instance, temperature, humidity) and the ability of scale-up. Despite the rapid increase in power conversion efficiency (PCE) of spin-coated devices fabricated in a protective atmosphere, the device efficiencies of printed nonfullerene OSC devices by blade-coating are still lower than 6%. This slow progress significantly limits the practical printing of high-performance nonfullerene OSCs. Here, a new and stable nonfullerene combination was introduced by pairing a commercially available nonfluorinated acceptor IT-M with the polymeric donor FTAZ. Over 12%-efficiency can be achieved in spincoated FTAZ:IT-M devices using a single halogen-free solvent. More importantly, chlorinefree, in air blade-coating of FTAZ:IT-M is able to yield a PCE of nearly 11%, despite a humidity of ~50%. X-ray scattering results reveal that large π-π coherence lengths, high degree of faceon orientation with respect to the substrate, and small domain spacings of ~20 nm are closely correlated with such high device performance. Our material system and approach yields the highest reported performance for nonfullerene OSC devices by a coating technique approximating scalable fabrication methods and holds great promise for the development of low-cost, low-toxicity, and high-efficiency OSCs by high-throughput production.

High temperature collecting performance of a new all-glass evacuated tubular solar air heater with U-shaped tube heat exchanger

International Nuclear Information System (INIS)

Wang, Pin-Yang; Guan, Hong-Yang; Liu, Zhen-Hua; Wang, Guo-San; Zhao, Feng; Xiao, Hong-Sheng

2014-01-01

Highlights: • A novel solar air heater with simplified CPC and U-type heat exchanger is designed and tested. • The system is made up of 10 linked collecting panels. • Simplified CPC has a much lower cost at the expense of slight efficiency loss. • The air heater can propose the heated air exceeding 200 °C with great air flow rate. - Abstract: Experiment and simulation are conducted on a new-type all-glass evacuated tubular solar air heater with simplified compound parabolic concentrator (CPC). The system is made up of 10 linked collecting panels and each panel includes a simplified CPC and an all-glass evacuated tube with a U-shaped copper tube heat exchanger installed inside. Air is gradually heated when passing through each U-shaped copper tube. The heat transfer model of the solar air heater is established and the outlet air temperature, the heat power and heat efficiency are calculated. Calculated and experimental results show that the present experimental system can provide the heated air exceeding 200 °C. The whole system has an outstanding high-temperature collecting performance and the present heat transfer model can meet the general requirements of engineering calculations

Strategy Guideline: Compact Air Distribution Systems

Energy Technology Data Exchange (ETDEWEB)

Burdick, A.

2013-06-01

This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine

Science.gov (United States)

Hoffman, Richard W., Jr.; Fatemi, Navid S.; Wilt, David M.; Jenkins, Phillip P.; Brinker, David J.; Scheiman, David A.

1994-01-01

Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

Continuous Photo-Oxidation in a Vortex Reactor: Efficient Operations Using Air Drawn from the Laboratory.

Science.gov (United States)

Lee, Darren S; Amara, Zacharias; Clark, Charlotte A; Xu, Zeyuan; Kakimpa, Bruce; Morvan, Herve P; Pickering, Stephen J; Poliakoff, Martyn; George, Michael W

2017-07-21

We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen ( 1 O 2 ) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with 1 O 2 , Hock cleavage with H + , and an oxidative cyclization cascade with triplet oxygen ( 3 O 2 ), from dihydroartemisinic acid was carried out as a single process in the vortex reactor.

High strength air-dried aerogels

Science.gov (United States)

Coronado, Paul R.; Satcher, Jr., Joe H.

2012-11-06

A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

Cost-effectiveness of high-efficiency appliances in the U.S. residential sector: A case study

International Nuclear Information System (INIS)

McNeil, Michael A.; Bojda, Nicholas

2012-01-01

This paper presents an analysis of the cost-effectiveness of high-efficiency appliances in the U.S. residential sector using cost and efficiency data developed as part of the regulatory process of the U.S. Department of Energy's Appliances and Commercial Equipment Standards Program. These data are presented as a case study in the development of an ‘efficiency technology database’ which can be expanded and published as a resource to other researchers and policy makers seeking scenarios that optimize efficiency policies and forecast their likely impacts on energy demand and greenhouse gas emissions. The use of this data to evaluate cost-effectiveness according to a variety of metrics is demonstrated using the example of one refrigerator–freezer product class. Cost-effectiveness is then evaluated in terms of cost of conserved energy for refrigerators, room air conditioners, water heaters, cooking equipment, central air conditioners and gas furnaces. The resulting potential of cost-effective improvement ranges from 1% to 53% of energy savings, with a typical potential of 15–20%. - Highlights: ► We determined the potential for cost-effective efficiency for residential appliances. ► We cover 6 appliance groups using cost of conserved energy as a metric for cost-effectiveness. ► Data are source from the DOE's Appliance and Commercial Equipment Standards Program. ► Between 15% and 20% additional cost-effective efficiency improvement is possible.

Incorporating fan control into air-conditioning systems to improve energy efficiency and transient response

International Nuclear Information System (INIS)

Yeh, T.-J.; Chen, Yun-Jih; Hwang, Wei-Yang; Lin, Jin-Long

2009-01-01

Modern air-conditioners frequently incorporate variable-speed compressors and variable-opening expansion valves with feedback control to improve performance and power efficiency. Because making the fan speeds adjustable adds flexibility to the control design and thus can lead to further improvements in performance and efficiency, this paper proposes two control algorithms, respectively, incorporating the outdoor fan and the indoor fan as the additional control inputs for air-conditioning systems. Both of the control algorithms are designed based on a low-order, linear model obtained from system identification. The first algorithm, which modulates the outdoor fan speed, can reduce the steady state power consumption if the temperature difference between the condenser and the outdoor environment is controlled properly. The second algorithm, which adds one more degree of freedom to control by modulating the indoor fan speed, can improve the transient response because actuator saturations become less likely to occur. The two control algorithms are implemented on a split-type residential air-conditioner and their respective performance is validated experimentally.

Feasibility for the medium efficiency filter as a postfilter in the air cleaning unit

International Nuclear Information System (INIS)

Lim, H. S.; Jung, D. Y.; Byun, S. C.; Kim, S. H.

2002-01-01

The Air Cleaning Unit (ACU) is provided in a nuclear facility to filter the radioactive materials in gaseous effluents released from the facility during normal operation and during a postulated accident. The Air Cleaning Unit (ACU) consists of pre-HEPA filters, charcoal adsorber, post HEPA filters, fans, etc. The charcoal filters keep on-site dose and off-site effluents ALARA, consistent with regulatory requirements. The function of HEPA filter downstream of charcoal(carbon) adsorber in ACU is to catch potential radioactive carbon dust and to be a backup in the event of failure of upstream HEPA. Previous Regulatory Guide use only post HEPA filter of charcoal adsorber downstream but the Regulatory Guide of current revisions allows use of 95% dust spot efficiency filters in lieu of HEPA at the downstream of the carbon adsorber. In this paper is described that the background information of filters, Current Regulatory Guide of revised by the United States Nuclear Regulatory Commission and the feasibility for the medium efficiency filter as a carbon adsorber post filter in the Air Cleaning Unit

THE EFFECT OF THE REYNOLDS NUMBER OF AIR FLOW TO THE PARTICLE COLLECTION EFFICIENCY OF A FIBROUS FILTER MEDIUM WITH CYLINDRICAL SECTION

Directory of Open Access Journals (Sweden)

George P. Kouropoulos

2014-01-01

Full Text Available At this study an attempt for the theoretical approach of the Re ynolds number effect of air flow to the particle collection efficiency of a fibrous fil ter with cylindrical section will be made. Initially, a report of the air filtration models to fibrous filter media will be presented along with an explanation of both the parameters and the physical quantities which govern the air filtration process. Furthermore, the resul ting equation from the mathematical model will be applied to a real filter medium and the characteristic curves of filter efficiency will be drawn. The change of a filter medi um efficiency with regard to the Reynolds number of air flow that passes through the filt er, derived from the curves, will be studied. The general conclusion that we have is that as the Reynolds number of filtered air increases, the collection efficiency of the filter decreases.

The impact of portable high-efficiency particulate air filters on the incidence of invasive aspergillosis in a large acute tertiary-care hospital.

Science.gov (United States)

Abdul Salam, Zakir-Hussain; Karlin, Rubiyah Binte; Ling, Moi Lin; Yang, Kok Soong

2010-05-01

Worldwide, the frequency of invasive fungal infections has been increasing, with a corresponding increase in the numbers of high-risk patients. Exposure reduction through the use of high-efficiency particulate air (HEPA) filters has been the preferred primary preventive strategy for these high-risk patients. Although the efficiency and benefits of fixed HEPA filters is well proven, the benefits of portable HEPA filters are still inconclusive. This was a retrospective study to assess the impact of 48 portable HEPA filter units deployed in selected wards in Singapore General Hospital, an acute tertiary-care hospital in Singapore. Data were extracted between December 2005 and June 2008 on the diagnoses at discharge and microbiological and histological laboratory findings. All patients with possible, probable, or proven invasive aspergillosis (IA) were included. In wards with portable HEPA filters, the incidence rate of IA of 34.61/100,000 patient-days in the pre-installation period was reduced to 17.51/100,000 patient-days in the post-installation period (P = .01), for an incidence rate ratio of 1.98 (95% confidence interval [CI], 1.10-2.97). In wards with no HEPA filters, there was no significant change in the incidence rate during the study period. Portable HEPA filters were associated with an adjusted odds ratio of 0.49 (95% CI, 0.28-0.85; P = .01), adjusted for diagnosis and length of hospital stay. Portable HEPA filters are effective in the prevention of IA. The cost of widespread portable HEPA filtration in hospitals will be more than offset by the decreases in nosocomial infections in general and in IA in particular. Copyright (c) 2010 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

An efficient modeling of fine air-gaps in tokamak in-vessel components for electromagnetic analyses

International Nuclear Information System (INIS)

Oh, Dong Keun; Pak, Sunil; Jhang, Hogun

2012-01-01

Highlights: ► A simple and efficient modeling technique is introduced to avoid undesirable massive air mesh which is usually encountered at the modeling of fine structures in tokamak in-vessel component. ► This modeling method is based on the decoupled nodes at the boundary element mocking the air gaps. ► We demonstrated the viability and efficacy, comparing this method with brute force modeling of air-gaps and effective resistivity approximation instead of detail modeling. ► Application of the method to the ITER machine was successfully carried out without sacrificing computational resources and speed. - Abstract: A simple and efficient modeling technique is presented for a proper analysis of complicated eddy current flows in conducting structures with fine air gaps. It is based on the idea of replacing a slit with the decoupled boundary of finite elements. The viability and efficacy of the technique is demonstrated in a simple problem. Application of the method to electromagnetic load analyses during plasma disruptions in ITER has been successfully carried out without sacrificing computational resources and speed. This shows the proposed method is applicable to a practical system with complicated geometrical structures.

Analysis of heat recovery from a spray dryer by recirculation of exhaust air

International Nuclear Information System (INIS)

Golman, Boris; Julklang, Wittaya

2014-01-01

Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

Applying a novel extra-low temperature dedicated outdoor air system in office buildings for energy efficiency and thermal comfort

International Nuclear Information System (INIS)

Li, Han; Lee, W.L.; Jia, Jie

2016-01-01

Highlights: • A novel dedicated outdoor air system was proposed and investigated. • The proposed system adopts extra-low temperature outdoor air for space cooling. • The extra-low temperature air was generated by a multi-stage direct expansion coil. • Heat pipe was added to the proposed system to recover the waste cooling energy. • Energy and exergy analysis as well as thermal comfort analysis were conducted. - Abstract: A novel dedicated outdoor air system consisting of a multi-stage direct expansion coil and a zero-energy heat pipe to generate extra-low temperature outdoor air to avoid moisture-related problems was proposed in this study. The proposed system’s performance in achieving the desirable air conditions and better energy efficiency objectives is compared with a conventional direct expansion system for air-conditioning of a typical office building in Hong Kong based on simulation investigations. The simulations were carried out using equipment performance data of a pilot study, and realistic building and system characteristics. It was found that the proposed system, as compared to the conventional system, could reduce the annual indoor discomfort hours by 69.4%. An energy and exergy analysis was also conducted. It was revealed that the proposed system could reduce the annual air-conditioning energy use by 15.6% and the system exergy loss rate by 13.6%. The associated overall exergy efficiency was also found 18.6% higher. The findings of this study confirm that the proposed system is better than the conventional system in terms of both energy and exergy efficiency and the desirable air conditions.

Assessment of ventilation efficiency for the study of indoor air quality; Appreciation de l'efficacite de la ventilation pour l'etude de la qualite de l'air interieur

Energy Technology Data Exchange (ETDEWEB)

Akoua, A.A.

2004-10-15

An efficient ventilation system provides a good indoor air quality by eliminating air pollutants and ensuring a satisfactory air renewal. Unlike most research works that deal with test cells with controlled boundary conditions, our study focuses on ventilation efficiency in a real environment. In situ experiments are performed and provide the boundary conditions necessary for CFD (Computational Fluid Dynamics) computations. Using CFD for predicting indoor air quality in a real environment is thus analyzed. The influence of permeability on numerical predictions quality is shown. Unfortunately, it is difficult to quantify accurately the air leakages and their airflow rates. Our study proposes a simplified model that includes air infiltration rates in the CFD computations, and that yields satisfactory results. A critical analysis of ventilation efficiency indices is then performed. It is shown that it is currently impossible to evaluate the air change efficiency ( a e ) in an occupied zone. Concerning the air pollutants removal effectiveness, it is shown that the usual index C e is not suited to ventilation systems with variable airflow rates. For such cases, a new formulation of this index is given. The ratio between the airflow rate and the nominal airflow rate of the ventilation system is also taken into consideration. A coupled analysis of this new index and of this airflow rate ratio enables us to assess the air pollutants removal effectiveness while considering the energetic cost of ventilation. We finally show that there is no universal index. The choice of the index depends on the pollutant, on the pollutant concentration, and on the airflow rate. A tool of decision-making aid is thus proposed in order to evaluate the air pollutants removal effectiveness for various ventilation systems. This tool is flexible and rather simple to use. (author)

Assessment of commercially available energy-efficient room air conditioners including models with low global warming potential (GWP) refrigerants

Energy Technology Data Exchange (ETDEWEB)

Shah, N. K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, W. Y. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gerke, B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-08-30

Improving the energy efficiency of room air conditioners (RACs) while transitioning to low global-warming-potential (GWP) refrigerants will be a critical step toward reducing the energy, peak load, and emissions impacts of RACs while keeping costs low. Previous research quantified the benefits of leapfrogging to high efficiency in tandem with the transition to low-GWP refrigerants for RACs (Shah et al., 2015) and identified opportunities for initial action to coordinate energy efficiency with refrigerant transition in economies constituting about 65% of the global RAC market (Shah et al., 2017). This report describes further research performed to identify the best-performing (i.e., most efficient and low-GWP-refrigerant using) RACs on the market, to support an understanding of the best available technology (BAT). Understanding BAT can help support market-transformation programs for high-efficiency and low-GWP equipment such as minimum energy performance standards (MEPS), labeling, procurement, and incentive programs. We studied RACs available in six economies—China, Europe, India, Japan, South Korea, and the United States—that together account for about 70% of global RAC demand, as well as other emerging economies. The following are our key findings: • Highly efficient RACs using low-GWP refrigerants, e.g., HFC-32 (R-32) and HC-290 (R-290), are commercially available today at prices comparable to similar RACs using high-GWP HCFC-22 (R-22) or HFC-410A (R-410A). • High efficiency is typically a feature of high-end products. However, highly efficient, cost-competitive (less than 1,000 or 1,500 U.S. dollars in retail price, depending on size) RACs are available. • Where R-22 is being phased out, high GWP R-410A still dominates RAC sales in most mature markets except Japan, where R-32 dominates. • In all of the economies studied except Japan, only a few models are energy efficient and use low-GWP refrigerants. For example, in Europe, India, and Indonesia

In-situ continuous scanning high efficiency particulate air (HEPA) filter monitoring system

International Nuclear Information System (INIS)

Kirchner, K.N.; Johnson, C.M.; Lucerna, J.J.; Barnett, R.L.

1985-01-01

The testing and replacement of HEPA filters, which are widely used in the nuclear industry to purify process air before it is ventilated to the atmosphere, is a costly and labor-intensive undertaking. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow for determination of overall filter performance but preclude detection of symptoms of incipient filter failure, such as small holes in the filters themselves. Using current technology, a continual in-situ monitoring system has been designed which provides three major improvements over current methods of filter testing and replacement. This system (1) realizes a cost savings by reducing the number of intact filters which are currently being replaced unnecessarily, (2) provides a more accurate and quantitative measurement of filter performance than is currently achieved with existing testing methods, and (3) reduces personnel exposure to a radioactive environment by automatically performing most testing operations. The operation and performance of the HEPA filter monitoring system are discussed

Measurements and predictions of the air distribution systems in high compute density (Internet) data centers

Energy Technology Data Exchange (ETDEWEB)

Cho, Jinkyun [HIMEC (Hanil Mechanical Electrical Consultants) Ltd., Seoul 150-103 (Korea); Department of Architectural Engineering, Yonsei University, Seoul 120-749 (Korea); Lim, Taesub; Kim, Byungseon Sean [Department of Architectural Engineering, Yonsei University, Seoul 120-749 (Korea)

2009-10-15

When equipment power density increases, a critical goal of a data center cooling system is to separate the equipment exhaust air from the equipment intake air in order to prevent the IT server from overheating. Cooling systems for data centers are primarily differentiated according to the way they distribute air. The six combinations of flooded and locally ducted air distribution make up the vast majority of all installations, except fully ducted air distribution methods. Once the air distribution system (ADS) is selected, there are other elements that must be integrated into the system design. In this research, the design parameters and IT environmental aspects of the cooling system were studied with a high heat density data center. CFD simulation analysis was carried out in order to compare the heat removal efficiencies of various air distribution systems. The IT environment of an actual operating data center is measured to validate a model for predicting the effect of different air distribution systems. A method for planning and design of the appropriate air distribution system is described. IT professionals versed in precision air distribution mechanisms, components, and configurations can work more effectively with mechanical engineers to ensure the specification and design of optimized cooling solutions. (author)

OFFER SOLUTIONS FOR THE DEVELOPMENT OF PROJECTS OF ENERGY-EFFICIENT HIGH-RISE BUILDINGS IN UKRAINE

Directory of Open Access Journals (Sweden)

DYACHENKO L. Yu.

2016-04-01

Full Text Available Raising of problem. Today, the question of ecology is in the first place all over the world. Our homes are not just destroying nature, but also need a lot of energy. 40% of the world's energy goes to lighting, air conditioning, heating, etc. Ukraine is a country, in which there are many cities with large industrial zones. By introducing a number of innovations for increasing energy efficiency we can improve the ecological situation in the country. The purpose of the article is offer solutions for the development of projects of energy-efficient high-rise buildings in Ukraine. Conclusion. Proposed solutions for the development of projects of energy-efficient high-rise buildings in Ukraine will allow to solve the problems: ecology, energy saving, saving of natural resources in the country in the near future.

Enhanced Adsorption Efficiency through Materials Design for Direct Air Capture over Supported Polyethylenimine.

Science.gov (United States)

Sayari, Abdelhamid; Liu, Qing; Mishra, Prashant

2016-10-06

Until recently, carbon capture and sequestration (CCS) was regarded as the most promising technology to address the alarming increase in the concentration of anthropogenic CO 2 in the atmosphere. There is now an increasing interest in carbon capture and utilization (CCU). In this context, the capture of CO 2 from air is an ideal solution to supply pure CO 2 wherever it is needed. Here, we describe innovative materials for direct air capture (DAC) with unprecedented efficiency. Polyethylenimine (PEI) was supported on PME, which is an extra-large-pore silica (pore-expanded MCM-41) with its internal surfaces fully covered by a uniform layer of readily accessible C 16 chains from cetyltrimethylammonium (CTMA + ) cations. The CTMA + layer plays a key role in enhancing the amine efficiency toward dry or humid ultradilute CO 2 (400 ppm CO 2 /N 2 ) to unprecedented levels. At the same PEI content, the amine efficiency of PEI/PME was two to four times higher than that of the corresponding calcined mesoporous silica loaded with PEI or with different combinations of C 16 chains and PEI. Under humid conditions, the amine efficiency of 40 wt % PEI/PME reached 7.31 mmolCO2 /g PEI , the highest ever reported for any supported PEI in the presence of 400 ppm CO 2 . Thus, amine accessibility, which reflects both the state of PEI dispersion and the adsorption efficiency, is intimately associated with the molecular design of the adsorbent. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complex analysis of energy efficiency in operated high-rise residential building: Case study

Science.gov (United States)

Korniyenko, Sergey

2018-03-01

Energy conservation and human thermal comfort enhancement in buildings is a topical issue of modern architecture and construction. The innovative solution of this problem makes it possible to enhance building ecological and maintenance safety, to reduce hydrocarbon fuel consumption, and to improve life standard of people. The requirements to increase of energy efficiency in buildings should be provided at all the stages of building's life cycle that is at the stage of design, construction and maintenance of buildings. The research purpose is complex analysis of energy efficiency in operated high-rise residential building. Many actions for building energy efficiency are realized according to the project; mainly it is the effective building envelope and engineering systems. Based on results of measurements the energy indicators of the building during annual period have been calculated. The main reason of increase in heat losses consists in the raised infiltration of external air in the building through a building envelope owing to the increased air permeability of windows and balcony doors (construction defects). Thermorenovation of the building based on ventilating and infiltration heat losses reduction through a building envelope allows reducing annual energy consumption. Energy efficiency assessment based on the total annual energy consumption of building, including energy indices for heating and a ventilation, hot water supply and electricity supply, in comparison with heating is more complete. The account of various components in building energy balance completely corresponds to modern direction of researches on energy conservation and thermal comfort enhancement in buildings.

New Source Review and coal plant efficiency gains: How new and forthcoming air regulations affect outcomes

International Nuclear Information System (INIS)

Adair, Sarah K.; Hoppock, David C.; Monast, Jonas J.

2014-01-01

Forthcoming carbon dioxide (CO 2 ) regulations for existing power plants in the United States have heightened interest in thermal efficiency gains for coal-fired power plants. Plant modifications to improve thermal efficiency can trigger New Source Review (NSR), a Clean Air Act requirement to adopt of state-of-the-art pollution controls. This article explores whether existing coal plants would likely face additional pollution control requirements if they undertake modifications that trigger NSR. Despite emissions controls that are or will be installed under the Mercury and Air Toxics Standards (MATS) and Clean Air Interstate Rule (CAIR) or its replacement, 80% of coal units (76% of capacity) that are expected to remain in operation are not projected to meet the minimum NSR requirements for at least one pollutant: nitrogen oxides or sulfur dioxide. This is an important consideration for the U.S. Environmental Protection Agency and state policymakers as they determine the extent to which CO 2 regulation will rely on unit-by-unit thermal efficiency gains versus potential flexible compliance strategies such as averaging, trading, energy efficiency, and renewable energy. NSR would likely delay and add cost to thermal efficiency projects at a majority of coal units, including projects undertaken to comply with forthcoming CO 2 regulation. - Highlights: • We explore the status of the U.S. coal-fired fleet relative to New Source Review (NSR) requirements. • Modifications to improve thermal efficiency can trigger NSR. • Thermal efficiency gains may also be an important strategy for forthcoming CO 2 regulation. • 80% Of non-retiring coal-fired units are projected not to meet minimum NSR requirements. • NSR is an important consideration for the design of CO 2 regulations for existing plants

Indoor air quality in energy-efficient dwellings: Levels and sources of pollutants.

Science.gov (United States)

Derbez, M; Wyart, G; Le Ponner, E; Ramalho, O; Ribéron, J; Mandin, C

2018-03-01

Worldwide, public policies are promoting energy-efficient buildings and accelerating the thermal renovation of existing buildings. The effects of these changes on the indoor air quality (IAQ) in these buildings remain insufficiently understood. In this context, a field study was conducted in 72 energy-efficient dwellings to describe the pollutants known to be associated with health concerns. Measured parameters included the concentrations of 19 volatile organic compounds and aldehydes, nitrogen dioxide, particulate matter (PM 2.5 ), radon, temperature, and relative humidity. The air stuffiness index and night-time air exchange rate were calculated from the monitored carbon dioxide (CO 2 ) concentrations. Indoor and outdoor measurements were performed at each dwelling during 1 week in each of the two following seasons: heating and non-heating. Moreover, questionnaires were completed by the occupants to characterize the building, equipment, household, and occupants' habits. Perspective on our results was provided by previous measurements made in low-energy European dwellings. Statistical comparisons with the French housing stock and a pilot study showed higher concentrations of terpenes, that is, alpha-pinene and limonene, and hexaldehyde in our study than in previous studies. Alpha-pinene and hexaldehyde are emitted by wood or wood-based products used for the construction, insulation, decoration, and furnishings of the dwellings, whereas limonene is more associated with discontinuous sources related to human activities. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of cooking energy cost, efficiency, impact on air pollution and policy in Nigeria

International Nuclear Information System (INIS)

Anozie, A.N.; Bakare, A.R.; Sonibare, J.A.; Oyebisi, T.O.

2007-01-01

This study evaluated the cooking energy costs and efficiencies, the air pollution impacts of cooking energy consumption and the impact of the energy policy in the cooking energy sector in Nigeria. Water boiling and cooking experiments using the common cooking energy sources (fuel wood, kerosene, liquefied petroleum gas (LPG) and electricity) and common food items (water, yam and beans) were carried out. Energy surveys were carried out to determine the cooking energy use patterns in the urban and rural areas. It was found that fuel wood is the least expensive cooking energy source and LPG is the most expensive. Energy use efficiencies for boiling water were estimated at 25%, 46%, 73%, 79%, 66% and 90% for fuel wood, kerosene, gas, electric immersion coil, electric heating coil and electric hot plate, respectively. Energy intensity was found to be a comparative measure of energy efficiency. The impacts of air pollution from household cooking suggested a possibility of significant air pollutants contribution to the ambient environment using any of the energy carriers considered except electricity. The cooking energy use patterns showed that fuel wood is the predominant energy source for cooking in the rural areas while kerosene is the predominant energy source in the urban areas, revealing that the energy policy in the country had made no impact in the cooking energy sector. Recommendations for improving the energy supply situation were given and for removing the barriers that prevent the implementation of the recommendations

Progress of OLED devices with high efficiency at high luminance

Science.gov (United States)

Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

2014-03-01

Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

High-power, high-efficiency FELs

International Nuclear Information System (INIS)

Sessler, A.M.

1989-04-01

High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

Design of a Hydraulic Motor System Driven by Compressed Air

Directory of Open Access Journals (Sweden)

Jyun-Jhe Yu

2013-06-01

Full Text Available This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is transformed by a hydraulic motor to mechanical energy to enhance the efficiency of using air power. To evaluate the theoretical efficiency, the principle of balance of energy is applied. The theoretical efficiency of converting air into hydraulic energy is found to be a function of pressure; thus, the maximum converting efficiency can be determined. To confirm the theoretical evaluation, a prototype of the pneumatic hydraulic system is built. The experiment verifies that the theoretical evaluation of the system efficiency is reasonable, and that the layout of the system is determined by the results of theoretical evaluation.

A primary study on the increasing of efficiency in the computer cooling system by means of external air

Energy Technology Data Exchange (ETDEWEB)

Kim, S. H.; Kim, M. H. [Silla University, Busan (Korea, Republic of)

2009-07-01

In recent years, since the continuing increase in the capacity of in personal computer such as the optimal performance, high quality and high resolution image, the computer system's components produce large amounts of heat during operation. This study analyzes and investigates an ability and efficiency of the cooling system inside the computer by means of Central Processing Unit (CPU) and power supply cooling fan. This research was conducted for increasing an ability of the cooling system inside the computer by making a structure which produces different air pressures in an air inflow tube. Consequently, when temperatures of the CPU and room inside computer were compared with a general personal computer, temperatures of the tested CPU, the room and the heat sink were as low as 5 .deg. C, 2.5 .deg. C and 7 .deg. C respectively. In addition to, Revolution Per Minute (RPM) was shown as low as 250 after 1 hour operation. This research explored the possibility of enhancing the effective cooling of high-performance computer systems.

Energy Efficiency and Air Quality Repairs at Lyonsdale Biomass

Energy Technology Data Exchange (ETDEWEB)

Brower, Michael R; Morrison, James A; Spomer, Eric; Thimot, Carol A

2012-07-31

This project enabled Lyonsdale Biomass, LLC to effect analyses, repairs and upgrades for its biomass cogeneration facility located in Lewis County, New York and close by the Adirondack Park to reduce air emissions by improving combustion technique and through the overall reduction of biomass throughput by increasing the system's thermodynamic efficiency for its steam-electrical generating cycle. Project outcomes result in significant local, New York State, Northeast U.S. and national benefits including improved renewable energy operational surety, enhanced renewable energy efficiency and more freedom from foreign fossil fuel source dependence. Specifically, the reliability of the Lyonsdale Biomass 20MWe woody biomass combined-heat and power (CHP) was and is now directly enhanced. The New York State and Lewis County benefits are equally substantial since the facility sustains 26 full-time equivalency (FTE) jobs at the facility and as many as 125 FTE jobs in the biomass logistics supply chain. Additionally, the project sustains essential local and state payment in lieu of taxes revenues. This project helps meet several USDOE milestones and contributes directly to the following sustainability goals:  Climate: Reduces greenhouse gas emissions associated with bio-power production, conversion and use, in comparison to fossil fuels. Efficiency and Productivity: Enhances efficient use of renewable resources and maximizes conversion efficiency and productivity. Profitability: Lowers production costs. Rural Development: Enhances economic welfare and rural development through job creation and income generation. Standards: Develop standards and corresponding metrics for ensuring sustainable biopower production. Energy Diversification and Security: Reduces dependence on foreign oil and increases energy supply diversity. Net Energy Balance: Ensures positive net energy balance for all alternatives to fossil fuels.

The evolution of air resonance power efficiency in the violin and its ancestors.

Science.gov (United States)

Nia, Hadi T; Jain, Ankita D; Liu, Yuming; Alam, Mohammad-Reza; Barnas, Roman; Makris, Nicholas C

2015-03-08

The fact that acoustic radiation from a violin at air-cavity resonance is monopolar and can be determined by pure volume change is used to help explain related aspects of violin design evolution. By determining the acoustic conductance of arbitrarily shaped sound holes, it is found that air flow at the perimeter rather than the broader sound-hole area dominates acoustic conductance, and coupling between compressible air within the violin and its elastic structure lowers the Helmholtz resonance frequency from that found for a corresponding rigid instrument by roughly a semitone. As a result of the former, it is found that as sound-hole geometry of the violin's ancestors slowly evolved over centuries from simple circles to complex f-holes, the ratio of inefficient, acoustically inactive to total sound-hole area was decimated, roughly doubling air-resonance power efficiency. F-hole length then slowly increased by roughly 30% across two centuries in the renowned workshops of Amati, Stradivari and Guarneri, favouring instruments with higher air-resonance power, through a corresponding power increase of roughly 60%. By evolution-rate analysis, these changes are found to be consistent with mutations arising within the range of accidental replication fluctuations from craftsmanship limitations with subsequent selection favouring instruments with higher air-resonance power.

New Source Review (NSR) Air Permitting and Energy Efficiency for Industrial Projects, IECA Manufacturers for Energy Efficiency Coalition Meeting (Presentation) – April 18, 2012

Science.gov (United States)

This presentation provides information about major new source review (NSR), including recent improvement changes and court rulings, flexible air permits rule, significant deterioration rules, and energy efficiency considerations.

Indoor air quality in energy efficient buildings. A literature review

Energy Technology Data Exchange (ETDEWEB)

Thomsen, Judith; Berge, Magnar

2012-07-01

There is currently a major focus on measures to reduce global warming. Several international studies show that the energy efficiency of buildings is the easiest and most cost-effective climate action. Passive houses are characterized of that the buildings are more airtight, have more insulation and has balanced mechanical ventilation with heat recovery. This report discusses about this one-sided focus on energy conservation, and if {sup c}hange{sup }in building methods can have a negative impact on indoor air quality and people's health. (Author)

Application of air ions for bacterial de-colonization in air filters contaminated by aerosolized bacteria

International Nuclear Information System (INIS)

Kim, Yang Seon; Yoon, Ki Young; Park, Jae Hong; Hwang, Jungho

2011-01-01

We aerosolized the Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) bacteria and collected them on membrane filters. Then we generated air ions by applying a high voltage to a carbon fiber tip and applied them to the contaminated filters. The antibacterial efficiency was not significantly affected by the bacteria being Gram-positive or Gram-negative, however, negative ions showed a lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions. With a field emission scanning electron microscope (FE-SEM) images and fluorescence microscopy images using a LIVE/DEAD BacLight Bacterial Viability Kit, electrostatic disruption of the bacteria was found to be the dominant antibacterial effect. - Research Highlights: →This study examined the effects of air ions generated by a carbon fiber ionizer on the inactivation of bioaerosols. →When the ion exposure time and the ion generation concentration were increased, the antibacterial efficiency increased. →The bioaerosols carried a significant number of negative electrical charges. →Negative ions showed lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions.

A high-efficiency electromechanical battery

Science.gov (United States)

Post, Richard F.; Fowler, T. K.; Post, Stephen F.

1993-03-01

In our society there is a growing need for efficient cost-effective means for storing electrical energy. The electric auto is a prime example. Storage systems for the electric utilities, and for wind or solar power, are other examples. While electrochemical cells could in principle supply these needs, the existing E-C batteries have well-known limitations. This article addresses an alternative, the electromechanical battery (EMB). An EMB is a modular unit consisting of an evacuated housing containing a fiber-composite rotor. The rotor is supported by magnetic bearings and contains an integrally mounted permanent magnet array. This article addresses design issues for EMBs with rotors made up of nested cylinders. Issues addressed include rotational stability, stress distributions, generator/motor power and efficiency, power conversion, and cost. It is concluded that the use of EMBs in electric autos could result in a fivefold reduction (relative to the IC engine) in the primary energy input required for urban driving, with a concomitant major positive impact on our economy and on air pollution.

Heterogeneous photocatalysis for air and water treatment: Fundamental needs for quantum efficiency enhancement

Energy Technology Data Exchange (ETDEWEB)

Ollis, D.F. [North Carolina State Univ., Raleigh, NC (United States)

1996-09-01

In the remediation industries, a useful treatment technology must be {open_quotes}general, robust, and cheap{close_quotes}. Among oxidation processes, heterogeneous photocatalysis is now broadly demonstrated to destroy common water and air contaminants. The potential process uses of highly stable titania, long lived lamps (one year), and room temperature operation, indicating a simple and robust process. We are left to address the third criterion: Can photocatalysis be {open_quotes}cheap{close_quotes}? In both liquid phase and gas phase treatment and purification by photocatalysis, it is established that the primary barrier to commercialization is often cost. Cost in return is dominated by the efficiency with which solar or lamp photons are harvested for productive light, and subsequent dark, reactions. This paper therefore defines fundamental needs in photocatalysis for pollution control in terms of activities which could lead to quantum efficiency enhancement. We first recall three related definitions. The quantum yield (QY) is the ratio of molecules of reactant converted per photon absorbed, a fundamental quantity. A less fundamental, but more easily measured variable is the quantum efficiency (QE), the ratio of molecules converted per photon entering the reactor. A third variable is the energy required per order of magnitude pollutant reduction, or EEO, a definition which provides for easy energy cost comparisons among different technologies. Each measure cited here reflects the photon, and thus the electrical, cost of this photochemistry.

HVAC design guidelines for effective indoor air quality

International Nuclear Information System (INIS)

Bladykas, M.P.

1993-01-01

Building owners, designers and occupants need to consider all the design measures that contribute to high indoor air quality. Building occupants, furnishings, equipment, and ambient air pollution all contribute to surmounting indoor air quality concerns. However, these can be minimized by following HVAC design guidelines which promote high indoor air quality while maintaining reasonable energy-efficiency. The possible liabilities and loss of business productivity due to air quality problems are too great to ignore

High efficiency cabin air filter in vehicles reduces drivers' roadway particulate matter exposures and associated lipid peroxidation

OpenAIRE

Yu, Nu; Shu, Shi; Lin, Yan; She, Jianwen; Ip, Ho Sai Simon; Qiu, Xinghua; Zhu, Yifang

2017-01-01

Commuters who spend long hours on roads are exposed to high levels of traffic related air pollutants (TRAPs). Despite some well-known multiple adverse effects of TRAPs on human health, limited studies have focused on mitigation strategies to reduce these effects. In this study, we measured fine particulate matter (PM2.5) and ultrafine particle (UFP) concentrations inside and outside 17 taxis simultaneously while they were driven on roadways. The drivers' urinary monohydroxylated polycyclic ar...

Numerical modeling of positive streamer in air in nonuniform fields: Efficiency of radicals production

International Nuclear Information System (INIS)

Kulikovsky, A.A.

2001-01-01

The efficiency of streamer corona depends on a number of factors such as geometry of electrodes, voltage pulse parameters, gas pressure etc. In a past 5 years a two-dimensional models of streamer in nonuniform fields in air have been developed. These models allow to simulate streamer dynamics and generation of species and to investigate the influence of external parameters on species production. In this work the influence of Laplacian field on efficiency of radicals generation is investigated

Development of Polysulfone Hollow Fiber Porous Supports for High Flux Composite Membranes: Air Plasma and Piranha Etching

Directory of Open Access Journals (Sweden)

Ilya Borisov

2017-02-01

Full Text Available For the development of high efficiency porous supports for composite membrane preparation, polysulfone (PSf hollow fiber membranes (outer diameter 1.57 mm, inner diameter 1.12 mm were modified by air plasma using the low temperature plasma treatment pilot plant which is easily scalable to industrial level and the Piranha etch (H2O2 + H2SO4. Chemical and plasma modification affected only surface layers and did not cause PSf chemical structure change. The modifications led to surface roughness decrease, which is of great importance for further thin film composite (TFC membranes fabrication by dense selective layer coating, and also reduced water and ethylene glycol contact angle values for modified hollow fibers surface. Furthermore, the membranes surface energy increased two-fold. The Piranha mixture chemical modification did not change the membranes average pore size and gas permeance values, while air plasma treatment increased pore size 1.5-fold and also 2 order enhanced membranes surface porosity. Since membranes surface porosity increased due to air plasma treatment the modified membranes were used as efficient supports for preparation of high permeance TFC membranes by using poly[1-(trimethylsilyl-1-propyne] as an example for selective layer fabrication.

Comparison of PM collection efficiency of Gent and Airmatrics MiniVol portable air sampler

International Nuclear Information System (INIS)

Begum, Bilkis A.; Biswas, Swapan K.

2005-01-01

Gent PM sampler was developed as an integral part of several International Atomic Energy Agency sponsored coordinated research programmes (CRP) for collecting air particulate samples. On the other hand, the MiniVol Portable Air Sampler is a commercial ambient air sampler for particulate matter and non-reactive gases used by different agencies. Air quality management system requires comparable air quality data to be collected by different stake holders for assessment and regulatory purposes. In order to compare the characteristics of Gent sampler with the MiniVol Portable Air Sampler, the reproducibility of the sample mass collection efficiency were examined and the measured mass concentrations were compared. It was found that in case of PM 10 both samplers collect almost same fraction of PM 10 mass when the Gent sampler was operated at 16 litre per minute flow rate. But in case of fine fraction, Portable sampler collects 70% higher PM 2.5 mass concentration compared to the Gent PM 2.2 mass concentrations. This is because, the Gent sampler was typically operated at 16 to 17 lpm resulting in an estimated 50% cut point of 2.2 μm.(author)

High-efficiency airfoil rudders applied to submarines

Directory of Open Access Journals (Sweden)

ZHOU Yimei

2017-03-01

Full Text Available Modern submarine design puts forward higher and higher requirements for control surfaces, and this creates a requirement for designers to constantly innovate new types of rudder so as to improve the efficiency of control surfaces. Adopting the high-efficiency airfoil rudder is one of the most effective measures for improving the efficiency of control surfaces. In this paper, we put forward an optimization method for a high-efficiency airfoil rudder on the basis of a comparative analysis of the various strengths and weaknesses of the airfoil, and the numerical calculation method is adopted to analyze the influence rule of the hydrodynamic characteristics and wake field by using the high-efficiency airfoil rudder and the conventional NACA rudder comparatively; at the same time, a model load test in a towing tank was carried out, and the test results and simulation calculation obtained good consistency:the error between them was less than 10%. The experimental results show that the steerage of a high-efficiency airfoil rudder is increased by more than 40% when compared with the conventional rudder, but the total resistance is close:the error is no more than 4%. Adopting a high-efficiency airfoil rudder brings much greater lifting efficiency than the total resistance of the boat. The results show that high-efficiency airfoil rudder has obvious advantages for improving the efficiency of control, giving it good application prospects.

Complex analysis of energy efficiency in operated high-rise residential building: Case study

Directory of Open Access Journals (Sweden)

Korniyenko Sergey

2018-01-01

Full Text Available Energy conservation and human thermal comfort enhancement in buildings is a topical issue of modern architecture and construction. The innovative solution of this problem makes it possible to enhance building ecological and maintenance safety, to reduce hydrocarbon fuel consumption, and to improve life standard of people. The requirements to increase of energy efficiency in buildings should be provided at all the stages of building's life cycle that is at the stage of design, construction and maintenance of buildings. The research purpose is complex analysis of energy efficiency in operated high-rise residential building. Many actions for building energy efficiency are realized according to the project; mainly it is the effective building envelope and engineering systems. Based on results of measurements the energy indicators of the building during annual period have been calculated. The main reason of increase in heat losses consists in the raised infiltration of external air in the building through a building envelope owing to the increased air permeability of windows and balcony doors (construction defects. Thermorenovation of the building based on ventilating and infiltration heat losses reduction through a building envelope allows reducing annual energy consumption. Energy efficiency assessment based on the total annual energy consumption of building, including energy indices for heating and a ventilation, hot water supply and electricity supply, in comparison with heating is more complete. The account of various components in building energy balance completely corresponds to modern direction of researches on energy conservation and thermal comfort enhancement in buildings.

The physics of pulsed streamer discharge in high pressure air and applications to engine techonologies

Science.gov (United States)

Lin, Yung-Hsu

The goal of this dissertation is to study high pressure streamers in air and apply it to diesel engine technologies. Nanosecond scale pulsed high voltage discharges in air/fuel mixtures can generate radicals which in turn have been shown to improve combustion efficiency in gasoline fueled internal combustion engines. We are exploring the possibility to extend such transient plasma generation and expected radical species generation to the range of pressures encountered in compression-ignition (diesel) engines having compression ratios of ˜20:1, thereby improving lean burning efficiency and extending the range of lean combustion. At the beginning of this dissertation, research into streamer discharges is reviewed. Then, we conducted experiments of streamer propagation at high pressures, calculated the streamer velocity based on both optical and electrical measurements, and the similarity law was checked by analyzing the streamer velocity as a function of the reduced electric field, E/P. Our results showed that the similarity law is invalid, and an empirical scaling factor, E/√P, is obtained and verified by dimensional analysis. The equation derived from the dimensional analysis will be beneficial to proper electrode and pulse generator design for transient plasma assisted internal engine experiments. Along with the high pressure study, we applied such technique on diesel engine to improve the fuel efficiency and exhaust treatment. We observed a small effect of transient plasma on peak pressure, which implied that transient plasma has the capability to improve the fuel consumption. In addition, the NO can be reduced effectively by the same technique and the energy cost is 30 eV per NO molecule.

High-efficiency green phosphorescent organic light-emitting diodes with double-emission layer and thick N-doped electron transport layer

Energy Technology Data Exchange (ETDEWEB)

Nobuki, Shunichiro, E-mail: shunichiro.nobuki.nb@hitachi.com [Hitachi Research Laboratory, Hitachi Ltd., 7-1-1 Omika-cho, Hitachi-city, Ibaraki 319-1292 (Japan); Wakana, Hironori; Ishihara, Shingo [Hitachi Research Laboratory, Hitachi Ltd., 7-1-1 Omika-cho, Hitachi-city, Ibaraki 319-1292 (Japan); Mikami, Akiyoshi [Dept. of Electrical Engineering, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichimachi, Ishikawa 921-8501 (Japan)

2014-03-03

We have developed green phosphorescent organic light-emitting diodes (OLEDs) with high external quantum efficiency of 59.7% and power efficiency of 243 lm/W at 2.73 V at 0.053 mA/cm{sup 2}. A double emission layer and a thick n-doped electron transport layer were adopted to improve the exciton recombination factor. A high refractive index hemispherical lens was attached to a high refractive index substrate for extracting light trapped inside the substrate and the multiple-layers of OLEDs to air. Additionally, we analyzed an energy loss mechanism to clarify room for the improvement of our OLEDs including the charge balance factor. - Highlights: • We developed high efficiency green phosphorescent organic light-emitting diode (OLED). • Our OLED had external quantum efficiency of 59.7% and power efficiency of 243 lm/W. • A double emission layer and thick n-doped electron transport layer were adopted. • High refractive index media (hemispherical lens and substrate) were also used. • We analyzed an energy loss mechanism to clarify the charge balance factor of our OLED.

Methyl iodide trapping efficiency of aged charcoal samples from Bruce-A emergency filtered air discharge systems

International Nuclear Information System (INIS)

Wren, J.C.; Moore, C.J.; Rasmussenn, M.T.; Weaver, K.R.

1999-01-01

Charcoal filters are installed in the emergency filtered air discharge system (EFADS) of multiunit stations to control the release of airborne radioiodine in the event of a reactor accident. These filters use highly activated charcoal impregnated with triethylenediamine (TEDA). The TEDA-impregnated charcoal is highly efficient in removing radioiodine from flowing airstreams. The iodine-removal efficiency of the charcoal is presumed to deteriorate slowly with age, but current knowledge of this effect is insufficient to predict with confidence the performance of aged charcoal following an accident. Experiments were performed to determine the methyl iodide removal efficiency of aged charcoal samples taken from the EFADS of Ontario Hydro's Bruce-A nuclear generating station. The charcoal had been in service for ∼4 yr. The adsorption rate constant and capacity were measured under post-loss-of-coolant accident conditions to determine the efficiency of the aged charcoal. The adsorption rate constants of the aged charcoal samples were observed to be extremely high, yielding a decontamination factor (DF) for a 20-cm-deep bed of the aged charcoal >1 X 10 15 . The results show that essentially no CH 3 I would escape from a 20-cm-deep bed of the aged charcoal and that the requirement for a DF of 1000 for organic iodides in the EFADS filters would be exceeded by a tremendous margin. With such high DFs, the release of iodine from a 20-cm-deep bed would be virtually impossible to detect. The adsorption capacities observed for the aged charcoal samples approach the theoretical chemisorption capacity of 5 wt% TEDA charcoal, indicating that aging in the EFADS for 4 yr has had a negligible impact on the adsorption capacity. The results indicate that the short- and long-term performances of the aged charcoal in the EFADS of Bruce-A following an accident would still far exceed performance requirements. (author)

[Characteristics of phosphorus uptake and use efficiency of rice with high yield and high phosphorus use efficiency].

Science.gov (United States)

Li, Li; Zhang, Xi-Zhou; Li, Tinx-Xuan; Yu, Hai-Ying; Ji, Lin; Chen, Guang-Deng

2014-07-01

A total of twenty seven middle maturing rice varieties as parent materials were divided into four types based on P use efficiency for grain yield in 2011 by field experiment with normal phosphorus (P) application. The rice variety with high yield and high P efficiency was identified by pot experiment with normal and low P applications, and the contribution rates of various P efficiencies to yield were investigated in 2012. There were significant genotype differences in yield and P efficiency of the test materials. GRLu17/AiTTP//Lu17_2 (QR20) was identified as a variety with high yield and high P efficiency, and its yields at the low and normal rates of P application were 1.96 and 1.92 times of that of Yuxiang B, respectively. The contribution rate of P accumulation to yield was greater than that of P grain production efficiency and P harvest index across field and pot experiments. The contribution rates of P accumulation and P grain production efficiency to yield were not significantly different under the normal P condition, whereas obvious differences were observed under the low P condition (66.5% and 26.6%). The minimal contribution to yield was P harvest index (11.8%). Under the normal P condition, the contribution rates of P accumulation to yield and P harvest index were the highest at the jointing-heading stage, which were 93.4% and 85.7%, respectively. In addition, the contribution rate of P accumulation to grain production efficiency was 41.8%. Under the low P condition, the maximal contribution rates of P accumulation to yield and grain production efficiency were observed at the tillering-jointing stage, which were 56.9% and 20.1% respectively. Furthermore, the contribution rate of P accumulation to P harvest index was 16.0%. The yield, P accumulation, and P harvest index of QR20 significantly increased under the normal P condition by 20.6%, 18.1% and 18.2% respectively compared with that in the low P condition. The rank of the contribution rates of P

High-Temperature High-Efficiency Solar Thermoelectric Generators

Energy Technology Data Exchange (ETDEWEB)

Baranowski, LL; Warren, EL; Toberer, ES

2014-03-01

Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

High-Performance Pressure Sensor for Monitoring Mechanical Vibration and Air Pressure

Directory of Open Access Journals (Sweden)

Yancheng Meng

2018-05-01

Full Text Available To realize the practical applications of flexible pressure sensors, the high performance (sensitivity and response time as well as more functionalities are highly desired. In this work, we fabricated a piezoresistive pressure sensor based on the micro-structured composites films of multi-walled carbon nanotubes (MWCNTs and poly (dimethylsiloxane (PDMS. In addition, we establish efficient strategies to improve key performance of our pressure sensor. Its sensitivity is improved up to 474.13 kPa−1 by minimizing pressure independent resistance of sensor, and response time is shorten as small as 2 μs by enhancing the elastic modulus of polymer elastomer. Benefiting from the high performance, the functionalities of sensors are successfully extended to the accurate detection of high frequency mechanical vibration (~300 Hz and large range of air pressure (6–101 kPa, both of which are not achieved before.

Accelerating Improvements in the Energy Efficiency of Room Air Conditioners (RACs) in India: Potential, Cost-Benefit, and Policies (Interim Assessment)

Energy Technology Data Exchange (ETDEWEB)

Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-06-01

Falling AC prices, increasing incomes, increasing urbanization, and high cooling requirements due to hot climate are all driving increasing uptake of Room Air Conditioners (RACs) in the Indian market. Air conditioning already comprises 40-60% of summer peak load in large metropolitan Indian cities such as Delhi and is likely to contribute 150 GW to the peak demand in 2030. Standards and labeling policies have contributed to improving the efficiency of RACs in India by about 2.5% in the last 10 years (2.5% per year) while inflation adjusted RAC prices have continued to decline. In this paper, we assess the technical feasibility, cost-benefit, and required policy enhancements by further accelerating the efficiency improvement of RACs in India. We find that there are examples of significantly more accelerated improvements such as those in Japan and Korea where AC efficiency improved by more than 7% per year resulting in almost a doubling of energy efficiency in 7 to 10 years while inflation adjusted AC prices continued to decline. We find that the most efficient RAC sold on the Indian market is almost twice as efficient as the typical AC sold on the market and hence see no technology constraints in a similar acceleration of improvement of efficiency. If starting 2018, AC efficiency improves at a rate of 6% instead of 3%, 40-60 GW of peak load (equivalent to connected load of 5-6 billion LED bulbs), and over 75 TWh/yr (equivalent to 60 million consumers consuming 100 kWh/month) will be saved by 2030; total peak load reduction would be as high as 50 GW. The net present value (NPV) of the consumer benefit between 2018-2030 will range from Rs 18,000 Cr in the most conservative case (in which prices don’t continue to decline and increase based estimates of today’s cost of efficiency improvement) to 140,000 Cr in a more realistic case (in which prices are not affected by accelerated efficiency improvement as shown by historical experience). This benefit is achievable by

The effects of an energy efficiency retrofit on indoor air quality.

Science.gov (United States)

Frey, S E; Destaillats, H; Cohn, S; Ahrentzen, S; Fraser, M P

2015-04-01

To investigate the impacts of an energy efficiency retrofit, indoor air quality and resident health were evaluated at a low-income senior housing apartment complex in Phoenix, Arizona, before and after a green energy building renovation. Indoor and outdoor air quality sampling was carried out simultaneously with a questionnaire to characterize personal habits and general health of residents. Measured indoor formaldehyde levels before the building retrofit routinely exceeded reference exposure limits, but in the long-term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long-term follow-up sampling within certain resident subpopulations (i.e. residents who report smoking and residents who had lived longer at the apartment complex). © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Series-Tuned High Efficiency RF-Power Amplifiers

DEFF Research Database (Denmark)

Vidkjær, Jens

2008-01-01

An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

Accelerating Energy Efficiency Improvements in Room Air Conditioners in India: Potential, Costs-Benefits, and Policies

OpenAIRE

Abhyankar, N; Shah, N; Park, WY; Phadke, AA

2017-01-01

Rising incomes, increasing urbanization, and large cooling demand prompted by India’s hot, humid climate are driving increasing uptake of room air conditioners (ACs). Air conditioning already accounts for 40-60% of summer peak load in large Indian cities such as Delhi and is on track to contribute 140 gigawatts (GW) ( 30%) to peak demand in 2030. India’s standards and labeling policies improved the market average efficiency of room ACs by about 35% between 2006 and 2016 (3% per year) even as ...

Stable high efficiency two-dimensional perovskite solar cells via cesium doping

KAUST Repository

Zhang, Xu

2017-08-15

Two-dimensional (2D) organic-inorganic perovskites have recently emerged as one of the most important thin-film solar cell materials owing to their excellent environmental stability. The remaining major pitfall is their relatively poor photovoltaic performance in contrast to 3D perovskites. In this work we demonstrate cesium cation (Cs) doped 2D (BA)(MA)PbI perovskite solar cells giving a power conversion efficiency (PCE) as high as 13.7%, the highest among the reported 2D devices, with excellent humidity resistance. The enhanced efficiency from 12.3% (without Cs) to 13.7% (with 5% Cs) is attributed to perfectly controlled crystal orientation, an increased grain size of the 2D planes, superior surface quality, reduced trap-state density, enhanced charge-carrier mobility and charge-transfer kinetics. Surprisingly, it is found that the Cs doping yields superior stability for the 2D perovskite solar cells when subjected to a high humidity environment without encapsulation. The device doped using 5% Cs degrades only ca. 10% after 1400 hours of exposure in 30% relative humidity (RH), and exhibits significantly improved stability under heating and high moisture environments. Our results provide an important step toward air-stable and fully printable low dimensional perovskites as a next-generation renewable energy source.

A Lithium-Air Battery Stably Working at High Temperature with High Rate Performance.

Science.gov (United States)

Pan, Jian; Li, Houpu; Sun, Hao; Zhang, Ye; Wang, Lie; Liao, Meng; Sun, Xuemei; Peng, Huisheng

2018-02-01

Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium-air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium-air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium-air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium-air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium-air battery can work stably at 140 °C with a high specific current of 10 A g -1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high-performance energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modelling study, efficiency analysis and optimisation of large-scale Adiabatic Compressed Air Energy Storage systems with low-temperature thermal storage

International Nuclear Information System (INIS)

Luo, Xing; Wang, Jihong; Krupke, Christopher; Wang, Yue; Sheng, Yong; Li, Jian; Xu, Yujie; Wang, Dan; Miao, Shihong; Chen, Haisheng

2016-01-01

Highlights: • The paper presents an A-CAES system thermodynamic model with low temperature thermal energy storage integration. • The initial parameter value ranges for A-CAES system simulation are identified from the study of a CAES plant in operation. • The strategies of system efficiency improvement are investigated via a parametric study with a sensitivity analysis. • Various system configurations are discussed for analysing the efficiency improvement potentials. - Abstract: The key feature of Adiabatic Compressed Air Energy Storage (A-CAES) is the reuse of the heat generated from the air compression process at the stage of air expansion. This increases the complexity of the whole system since the heat exchange and thermal storage units must have the capacities and performance to match the air compression/expansion units. Thus it raises a strong demand in the whole system modelling and simulation tool for A-CAES system optimisation. The paper presents a new whole system mathematical model for A-CAES with simulation implementation and the model is developed with consideration of lowing capital cost of the system. The paper then focuses on the study of system efficiency improvement strategies via parametric analysis and system structure optimisation. The paper investigates how the system efficiency is affected by the system component performance and parameters. From the study, the key parameters are identified, which give dominant influences in improving the system efficiency. The study is extended onto optimal system configuration and the recommendations are made for achieving higher efficiency, which provides a useful guidance for A-CAES system design.

Efficiency of ozone production by pulsed positive corona discharge in synthetic air

Energy Technology Data Exchange (ETDEWEB)

Simek, Milan [Institute of Plasma Physics, Department of Pulsed Plasma Systems, Academy of Sciences of the Czech Republic, Prague (Czech Republic)]. E-mail: simek@ipp.cas.cz; Clupek, Martin [Institute of Plasma Physics, Department of Pulsed Plasma Systems, Academy of Sciences of the Czech Republic, Prague (Czech Republic)

2002-06-07

We have studied the efficiency of ozone production by pulsed positive corona discharge in coaxial wire-cylinder geometry at atmospheric pressure. A corona discharge was generated by short ({approx}150 ns) high voltage pulses applied between a silver coated copper wire anode and stainless steel cylinder cathode in synthetic air. A pyrex probe and Teflon tube was used for collecting discharge products and an ozone concentration was monitored outside of the discharge chamber by a non-dispersive UV absorption technique. The production of ozone was investigated as a function of energy density (10{sup -4}-3x10{sup -1} Wh l{sup -1}) delivered to the discharge volume by combining the discharge frequency (0.1-10 Hz) and airflow rate (1-32 l min{sup -1}). From ozone concentration measurements we have evaluated the ozone production, yield and production energy cost. The ozone production yield and cost vary in the range of 15-55 g kWh{sup -1} and 35-110 eV/molecule. (author)

Co- and defect-rich carbon nanofiber films as a highly efficient electrocatalyst for oxygen reduction

Science.gov (United States)

Kim, Il To; Song, Myeong Jun; Shin, Seoyoon; Shin, Moo Whan

2018-03-01

Many efforts are continuously devoted to developing high-efficiency, low-cost, and highly scalable oxygen reduction reaction (ORR) electrocatalysts to replace precious metal catalysts. Herein, we successfully synthesize Co- and defect-rich carbon nanofibers (CNFs) using an efficient heat treatment approach involving the pyrolysis of electrospun fibers at 370 °C under air. The heat treatment process produces Co-decorated CNFs with a high Co mass ratio, enriched pyridinic N, Co-pyridinic Nx clusters, and defect-rich carbon structures. The synergistic effects from composition and structural changes in the designed material increase the number of catalytically active sites for the ORR in an alkaline solution. The prepared Co- and defect-rich CNFs exhibit excellent ORR activities with a high ORR onset potential (0.954 V vs. RHE), a large reduction current density (4.426 mA cm-2 at 0.40 V), and a nearly four-electron pathway. The catalyst also exhibits a better long-term durability than commercial Pt/C catalysts. This study provides a novel hybrid material as an efficient ORR catalyst and important insight into the design strategy for CNF-based hybrid materials as electrochemical electrodes.

An atomic-scale and high efficiency finishing method of zirconia ceramics by using magnetorheological finishing

Science.gov (United States)

Luo, Hu; Guo, Meijian; Yin, Shaohui; Chen, Fengjun; Huang, Shuai; Lu, Ange; Guo, Yuanfan

2018-06-01

Zirconia ceramics is a valuable crucial material for fabricating functional components applied in aerospace, biology, precision machinery, military industry and other fields. However, the properties of its high brittleness and high hardness could seriously reduce its finishing efficiency and surface quality by conventional processing technology. In this work, we present a high efficiency and high-quality finishing process by using magnetorheological finishing (MRF), which employs the permanent magnetic yoke with straight air gap as excitation unit. The sub-nanoscale surface roughness and damage free surface can be obtained after magnetorheological finishing. The XRD results and SEM morphologies confirmed that the mechanical shear removal with ductile modes are the dominant material removal mechanism for the magnetorheological finishing of zirconia ceramic. With the developed experimental apparatus, the effects of workpiece speed, trough speed and work gap on material removal rate and surface roughness were systematically investigated. Zirconia ceramics finished to ultra-smooth surface with surface roughness less than Ra 1 nm was repeatedly achieved during the parametric experiments. Additionally, the highest material removal rate exceeded 1 mg/min when using diamond as an abrasive particle. Magnetorheological finishing promises to be an adaptable and efficient method for zirconia ceramics finishing.

A distillation tray with high efficiency and excellent operating flexibility for viscous mixture separation

Directory of Open Access Journals (Sweden)

Li Qunsheng

2014-01-01

Full Text Available The flow-guided sieve-valve tray(FGS-VTwith high efficiency was designed to overcome the shortcoming of low operating flexibility of the flow-guided sieve tray. Its dimensions and geometry, as well as structure characteristics, were presented. The hydrodynamics and mass transfer performance, including dry-plate pressure drop, wet plate-pressure drop, weeping, entrainment and tray efficiency, of two types of FGS-VTs (FGS-VTs with 14 and 8 valves, respectively and one flow-guided sieve tray were tested in an air-water-oxygen cold model experiment with a 0.6 m diameter plexiglass column. The results demonstrate that FGS-VT with 14 valves works better than FGS-VT with 8 valves, and in comparison with the flow-guided sieve tray, the flow-guided sieve-valve tray with 14 valves has higher tray efficiency, bigger operating flexibility, and lower wet-plate pressure drop (when all the valves are opened fully.Additionally, two typical applications to separate the mixture with high viscosity, solid, powder, easy-to-foam or easy self-polymerization components proved the unique advantages of FGS-VT.

High-throughput liquid-absorption air-sampling apparatus and methods

Science.gov (United States)

Zaromb, Solomon

2000-01-01

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is 20% for vapors or airborne particulates in the 2-3.mu. range and >50% for particles larger than 4.mu.. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

High-throughput liquid-absorption air-sampling apparatus and methods

International Nuclear Information System (INIS)

2000-01-01

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is 20% for vapors or airborne particulates in the 2--3 microns range and > 50% for particles larger than 4 microns. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives

High efficiency, long life terrestrial solar panel

Science.gov (United States)

Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

1977-01-01

The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

Science.gov (United States)

Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

2015-11-01

This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

Exergetic efficiency analysis of hydrogen–air detonation in pulse detonation combustor using computational fluid dynamics

Directory of Open Access Journals (Sweden)

Pinku Debnath

2017-03-01

Full Text Available Exergy losses during the combustion process, heat transfer, and fuel utilization play a vital role in the analysis of the exergetic efficiency of combustion process. Detonation is thermodynamically more efficient than deflagration mode of combustion. Detonation combustion technology inside the pulse detonation engine using hydrogen as a fuel is energetic propulsion system for next generation. In this study, the main objective of this work is to quantify the exergetic efficiency of hydrogen–air combustion for deflagration and detonation combustion process. Further detonation parameters are calculated using 0.25, 0.35, and 0.55 of H2 mass concentrations in the combustion process. The simulations have been performed for converging the solution using commercial computational fluid dynamics package Ansys Fluent solver. The details of combustion physics in chemical reacting flows of hydrogen–air mixture in two control volumes were simulated using species transport model with eddy dissipation turbulence chemistry interaction. From these simulations it was observed that exergy loss in the deflagration combustion process is higher in comparison to the detonation combustion process. The major observation was that pilot fuel economy for the two combustion processes and augmentation of exergetic efficiencies are better in the detonation combustion process. The maximum exergetic efficiency of 55.12%, 53.19%, and 23.43% from deflagration combustion process and from detonation combustion process, 67.55%, 57.49%, and 24.89%, are obtained from aforesaid H2 mass fraction. It was also found that for lesser fuel mass fraction higher exergetic efficiency was observed.

Quasi-steady-state model of a counter flow air-to-air heat exchanger with phase change

DEFF Research Database (Denmark)

Rose, Jørgen; Nielsen, Toke Rammer; Kragh, Jesper

2008-01-01

-exchanger. Developing highly efficient heat-exchangers and strategies to avoid/remove frost formation implies the use of detailed models to predict and evaluate different heat-exchanger designs and strategies. This paper presents a quasi-steady-state model of a counter-flow air-to-air heat-exchanger that takes...

Energy efficient biological air cleaning for farm stable ventilation; Energieffektiv biologisk luftrensning til staldventilation

Energy Technology Data Exchange (ETDEWEB)

Groenborg Nicolaisen, C.; Hansen, Mads P.R. [Teknologisk Institut, Aarhus (Denmark); Stroem, J.; Soerensen, Keld [DXT. Danish Exergy Technology A/S, Skoerping (Denmark); Goetke, C. [Lokalenergi Aarhus, Viby J. (Denmark); Morsing, S.; Soerensen, Lars C. [SKOV A/S, Roslev (Denmark); Ladegaerd Jensen, T.; Pedersen, Poul [Videncenter for svineproduktion, Copenhagen (Denmark)

2013-05-01

The project has been designed to reduce energy consumption for air purification by 30% while having a payback period of maximum 3 years. The project has achieved very significant results which are far above the target. Particularly satisfying is the wide range of new components that are launched in late 2012. By implementing the newly developed system at 100% cleaning (LPC 13 ventilators and Dynamic multistep control) in relation to Best Practice (SKOV's original system with DA600 fans) in a concrete pigsty, a saving of 61% and a simple payback of 1.7 years is achieved. Similarly, it is found that the energy used for pump operation can be reduced by 37% with the new Dynamic sprinkling control. At 20% cleaning a potential saving of 15% per year and a payback period of between 0 and 5 years was found, which is dependent on the desired performance as the capacities in the bio-filter's upper capacity range between 26 thousand to 30 thousand m3 / h entails costs for an additional extraction unit in the new solution. Furthermore, the newly developed components proved highly suitable for standard installations without air cleaning where a savings potential is 53% and the payback period 1.5 years. Product-wise, the project formed the basis for the development of: 1. New energy-efficient ventilation units (LPC11, 12,13) that are suitable for air purification; 2. A new energy-saving control principle (Dynamic Multi-Step) which is particularly suitable for low-energy ventilators; 3. A new energy-saving flow measurement system for ventilating ducts (Dynamic air to the central exhaust); 4. An energy-saving pressure control in common ducts (pressure control as a function of outside temperature); 5. Proposal for a new energy-saving pump operation for sprinkling of biological filters (Dynamic sprinkling). (LN)

Comparison of ultrafiltration and dissolved air flotation efficiencies in industrial units during the papermaking process

OpenAIRE

Monte Lara, Concepción; Ordóñez Sanz, Ruth; Hermosilla Redondo, Daphne; Sánchez González, Mónica; Blanco Suárez, Ángeles

2011-01-01

The efficiency of an ultrafiltration unit has been studied and compared with a dissolved air flotation system to get water with a suited quality to be reused in the process. The study was done at a paper mill producing light weight coated paper and newsprint paper from 100% recovered paper. Efficiency was analysed by removal of turbidity, cationic demand, total and dissolved chemical oxygen demand, hardness, sulphates and microstickies. Moreover, the performance of the ultrafiltration unit an...

Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

Directory of Open Access Journals (Sweden)

Kotowicz Janusz

2014-09-01

Full Text Available Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of ‘zero-emission’ technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

Desiccant Enhanced Evaporative Air-Conditioning (DEVap): Evaluation of a New Concept in Ultra Efficient Air Conditioning

Energy Technology Data Exchange (ETDEWEB)

Kozubal, E.; Woods, J.; Burch, J.; Boranian, A.; Merrigan, T.

2011-01-01

NREL has developed the novel concept of a desiccant enhanced evaporative air conditioner (DEVap) with the objective of combining the benefits of liquid desiccant and evaporative cooling technologies into an innovative 'cooling core.' Liquid desiccant technologies have extraordinary dehumidification potential, but require an efficient cooling sink. DEVap's thermodynamic potential overcomes many shortcomings of standard refrigeration-based direct expansion cooling. DEVap decouples cooling and dehumidification performance, which results in independent temperature and humidity control. The energy input is largely switched away from electricity to low-grade thermal energy that can be sourced from fuels such as natural gas, waste heat, solar, or biofuels.

Ag-Cu nanoalloyed film as a high-performance cathode electrocatalytic material for zinc-air battery

Science.gov (United States)

Lei, Yimin; Chen, Fuyi; Jin, Yachao; Liu, Zongwen

2015-04-01

A novel Ag50Cu50 film electrocatalyst for oxygen reduction reaction (ORR) was prepared by pulsed laser deposition (PLD) method. The electrocatalyst actually is Ag-Cu alloyed nanoparticles embedded in amorphous Cu film, based on transmission electron microscopy (TEM) characterization. The rotating disk electrode (RDE) measurements provide evidence that the ORR proceed via a four-electron pathway on the electrocatalysts in alkaline solution. And it is much more efficient than pure Ag catalyst. The catalytic layer has maximum power density of 67 mW cm-2 and an acceptable cell voltage at 0.863 V when current densities increased up to 100 mA cm-2 in the Ag50Cu50-based primary zinc-air battery. The resulting rechargeable zinc-air battery exhibits low charge-discharge voltage polarization of 1.1 V at 20 mAcm-2 and high durability over 100 cycles in natural air.

Design and fabrication of a high performance inorganic tandem solar cell with 11.5% conversion efficiency

International Nuclear Information System (INIS)

Amiri, Omid; Mir, Noshin; Ansari, Fatemeh; Salavati-Niasari, Masoud

2017-01-01

Tandem solar cell is a design that combines two types of solar cells to benefit their advantages. We show a new concept for achieving highly efficient dye sensitized and quantum dot tandem solar cells. The new tandem cell further enhances the performance of the device, leading to a power conversion efficiency more than 11% under 1.5 Air Mass. To the best of our knowledge, this is the first time that the efficiency over 11 percent is achieved based on tandem solar cell. X-ray diffraction, Transmission Electron Microscopy, Scanning Electron Microscopy, Current-Voltage measurments, Intensity modulated photocurrent spectroscopy, intensity modulated photovoltage spectroscopy, Energy Dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, Barrett-Joyner-Halenda and absorption spectroscopy were used to characterize the fabricated solar cells.

New highly efficient piezoceramic materials

International Nuclear Information System (INIS)

Dantsiger, A.Ya.; Razumovskaya, O.N.; Reznichenko, L.A.; Grineva, L.D.; Devlikanova, R.U.; Dudkina, S.I.; Gavrilyachenko, S.V.; Dergunova, N.V.

1993-01-01

New high efficient piezoceramic materials with various combination of parameters inclusing high Curie point for high-temperature transducers using in atomic power engineering are worked. They can be used in systems for heated matters nondestructive testing, controllers for varied industrial power plants and other high-temperature equipment

Short Term Airing by Natural Ventilation

DEFF Research Database (Denmark)

Heiselberg, Per; Perino, M.

2010-01-01

The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies...... that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working...... airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective...

Air pollution forecast in cities by an air pollution index highly correlated with meteorological variables

International Nuclear Information System (INIS)

Cogliani, E.

2001-01-01

There are many different air pollution indexes which represent the global urban air pollution situation. The daily index studied here is also highly correlated with meteorological variables and this index is capable of identifying those variables that significantly affect the air pollution. The index is connected with attention levels of NO 2 , CO and O 3 concentrations. The attention levels are fixed by a law proposed by the Italian Ministries of Health and Environment. The relation of that index with some meteorological variables is analysed by the linear multiple partial correlation statistical method. Florence, Milan and Vicence were selected to show the correlation among the air pollution index and the daily thermic excursion, the previous day's air pollution index and the wind speed. During the January-March period the correlation coefficient reaches 0.85 at Milan. The deterministic methods of forecasting air pollution concentrations show very high evaluation errors and are applied on limited areas around the observation stations, as opposed to the whole urban areas. The global air pollution, instead of the concentrations at specific observation stations, allows the evaluation of the level of the sanitary risk regarding the whole urban population. (Author)

Impact of individually controlled facially applied air movement on perceived air quality at high humidity

Energy Technology Data Exchange (ETDEWEB)

Skwarczynski, M.A. [Faculty of Environmental Engineering, Institute of Environmental Protection Engineering, Department of Indoor Environment Engineering, Lublin University of Technology, Lublin (Poland); International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Copenhagen (Denmark); Melikov, A.K.; Lyubenova, V. [International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Copenhagen (Denmark); Kaczmarczyk, J. [Faculty of Energy and Environmental Engineering, Department of Heating, Ventilation and Dust Removal Technology, Silesian University of Technology, Gliwice (Poland)

2010-10-15

The effect of facially applied air movement on perceived air quality (PAQ) at high humidity was studied. Thirty subjects (21 males and 9 females) participated in three, 3-h experiments performed in a climate chamber. The experimental conditions covered three combinations of relative humidity and local air velocity under a constant air temperature of 26 C, namely: 70% relative humidity without air movement, 30% relative humidity without air movement and 70% relative humidity with air movement under isothermal conditions. Personalized ventilation was used to supply room air from the front toward the upper part of the body (upper chest, head). The subjects could control the flow rate (velocity) of the supplied air in the vicinity of their bodies. The results indicate an airflow with elevated velocity applied to the face significantly improves the acceptability of the air quality at the room air temperature of 26 C and relative humidity of 70%. (author)

High-light damage in air-dry thalli of the old forest lichen Lobaria pulmonaria - interactions of irradiance, exposure duration and high temperature

International Nuclear Information System (INIS)

Gauslaa, Y.; Solhaug, K.A.

1999-01-01

High-light damage in air-dry thalli of Lobaria pulmonaria were measured in the laboratory as reductions in maximal PSII efficiency (FV/FM) after a 48 h recovery in a hydrated state at low light to account for permanent damage. Thalli treated with the lowest light dose (90 mol photons m −2 ) recovered normal FV/FM-values with increasing irradiances (400–700 nm) up to 1000 µmol photons m −2 s −1 . Doubling this dose lowered the threshold level for damage from 1000 to 320 µmol photons m −2 s −1 , and reduced FV/FM at 1000 µmol photons m −2 s −1 by more than 50%. A second doubling of the dose to 360 mol photons m −2 caused damage at 200 µmol photons m −2 s −1 , and a nearly complete cessation of PSII efficiency occurred at 1000 µmol photons m −2 s −1 . No reciprocity of irradiance and duration of illumination for PSII function was found. The measured time-dependent decrease in FV/FM was remarkably similar for the naturally coupled, but artificially separated, light and temperature factors. Therefore, the damage of high light on desiccated L. pulmonaria seemed to be an additive effect of high irradiance and high temperatures. Air-dry thalli were highly heat susceptible, being affected already at temperatures around 40 °C. Logging operations in forests are likely to raise the solar radiation at remaining lichen sites to destructive levels. (author)

Energy efficiency of freezing tunnels: towards an optimal operation of compressors and air fans

Energy Technology Data Exchange (ETDEWEB)

Widell, Kristina Norne

2012-07-01

Fish is one of Norway's main exports, and can be shipped fresh, frozen or dried. This thesis examines the freezing of fish in batch tunnels and ways to increase the energy efficiency of this process. A fish freezing plant on the west coast of Norway was used as a baseline case and measurements were made of the freezing system. Different aspects of this system were simulated, mainly using MATLAB.The focus was on the compressors and the freezing tunnels of an industrial refrigeration system. The compressors and the freezing tunnel fans are the largest consumers of electricity, but they are often not operated at the highest efficiency. An analysis of the compressor operation showed that it was far from optimal, with several compressors often operating at part-load simultaneously. These were screw compressors regulated by slide valves, which provide easy capacity control, but also have low energy efficiency. The refrigeration system had several different sized compressors, and the results showed that it was possible to run the system with only one compressor at part-load operation. The total coefficient of performance was improved by as much as 29% for a low production period. A further analysis showed that installing a variable speed drive on one compressor would also improve energy efficiency and make capacity regulation straightforward.The freezing system included five batch freezing tunnels, each of which had a freezing capacity of more than 100 tonnes of pelagic fish. A typical freezing period lasted typically 20 h and decreased the fish temperature to -18?C or below. The main task was to develop a computer program that could simulate the freezing process and the refrigeration system and locate opportunities for improvement. The air velocities inside the freezing tunnel varied with location, which were pinpointed using the computational fluid dynamics software program Airpak. These velocities were used in freezing time calculations. It was shown that a guide

Efficiency of clay-TiO2 nanocomposites on the photocatalytic eliminationof a model hydrophobic air pollutant

Energy Technology Data Exchange (ETDEWEB)

Kibanova, Daria; Cervini-Silva, Javiera; Destaillats, Hugo

2009-01-01

Clay-supported TiO2 photocatalysts can potentially improve the performance of air treatment technologies via enhanced adsorption and reactivity of target volatile organic compounds (VOCs). In this study, a bench-top photocatalytic flow reactor was used to evaluate the efficiency of hectorite-TiO2 and kaolinite-TiO2, two novel composite materials synthesized in our laboratory. Toluene, a model hydrophobic VOC and a common indoor air pollutant, was introduced in the air stream at realistic concentrations, and reacted under UVA (gamma max = 365 nm) or UVC (gamma max = 254 nm) irradiation. The UVC lamp generated secondary emission at 185 nm, leading to the formation of ozone and other short-lived reactive species. Performance of clay-TiO2 composites was compared with that of pure TiO2 (Degussa P25), and with UV irradiation in the absence of photocatalyst under identical conditions. Films of clay-TiO2 composites and of P25 were prepared by a dip-coating method on the surface of Raschig rings, which were placed inside the flow reactor. An upstream toluene concentration of ~;;170 ppbv was generated by diluting a constant flow of toluene vapor from a diffusion source with dry air, or with humid air at 10, 33 and 66percent relative humidity (RH). Toluene concentrations were determined by collecting Tenax-TA (R) sorbent tubes downstream of the reactor, with subsequent thermal desorption -- GC/MS analysis. The fraction of toluene removed, percentR, and the reaction rate, Tr, were calculated for each experimental condition from the concentration changes measured with and without UV irradiation. Use of UVC light (UV/TiO2/O3) led to overall higher reactivity, which can be partially attributed to the contribution of gas phase reactions by short-lived radical species. When the reaction rate was normalized to the light irradiance, Tr/I gamma, the UV/TiO2 reaction under UVA irradiation was more efficient for samples with a higher content of TiO2 (P25 and Hecto-TiO2), but not for Kao

Energy efficiency improvements in air traffic: The case of Airbus A320 in Spain

International Nuclear Information System (INIS)

Cansino, José M.; Román, Rocío

2017-01-01

Structural improvements in aircraft design, seeking to improve energy efficiency, can significantly reduce greenhouse gas emissions (GHG) by reducing reduced fuel consumption. This research reviews improvements with the introduction of a structural component known as 'winglet;' these are positioned at the top of the aircraft wing, and increased Airbus Group A320 sales. Data used are taken from air traffic in Spain for the 2010–2014 period with projections being made for 2020. The results show that winglets reduce CO_2 equivalent emissions associated with Spain's air transport for the 2015–2020 period between 66.29 and 59.56 Gg. depending on the scenario considered in 2020. - Highlights: • Spanish air traffic is considered a key-GHG emission sector. • The aviation industry has drastically reduced its emissions. • To what extent could improved model to reduce fuel consumption and polluting emissions? • A320 Neo, A330 Neo and A380 Neo models are in the process of industrialisation. • Objectives fixed by Air Transport Action Group for 2020 are relevant.

Part load efficiency of packaged air-cooled water chillers with inverter driven scroll compressors

International Nuclear Information System (INIS)

Cecchinato, Luca

2010-01-01

In this paper different packaged air-cooled systems, operating on scroll compressors, are experimentally analysed from the point of view of the relation between energy efficiency and actual capacity. Single compressor, double compressors and double compressors with uneven volumetric capacity units are tested. Experimental tests demonstrated that cooling capacity control by means of variation of rotational speed is an suitable solution for improving the part load efficiency of these systems. Step capacity units obtained by splitting the system volumetric capacity between two compressors are also effective solutions. Nevertheless they appear to be more efficient than single inverter driven chillers only for part load conditions lower than 60%. In the analysed cooling capacity range (25-50 kW), tandem compressors chillers with one inverter driven compressor appear the most efficient solution combining rotational speed with step capacity control. Seasonal energy efficiency ratios were obtained with prEN 14825 calculation method confirming reduced energy consumption associated to continuous and step cooling capacity control.

Efficient synthesis of superparamagnetic magnetite nanoparticles under air for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Saxena, Namita, E-mail: saxenanamita@yahoo.com [School of Nano Sciences, Central University of Gujarat, Gandhinagar 382030 (India); Singh, Man, E-mail: mansingh50@hotmail.com [School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030 (India)

2017-05-01

The facile co-precipitation process of synthesising Superparamagnetic Iron Oxide Nanoparticles (SPIONs) especially magnetite was investigated and simplified, to develop a reproducible and scaled up synthesis process under air, for producing particles with enhanced percentage of magnetite, thus eliminating the crucial and complicated need of using the inert atmosphere. Presence of magnetite was confirmed by XRD, TEM, and Raman spectroscopy. Efficiency of synthesising magnetite was increased up to approx. ∼58 wt%, under air with no other phases but maghemite present. Alkali concentration was optimised, and particles with better magnetisation values were synthesised. The approximate weight percentage of magnetite was calculated using the simple and rapid XRD peak deconvolution method. Higher pH values from 13 to14 were investigated in the study while alkali concentration was varied from 0.5 to 4 M. 1Molar NaOH with a final pH of 13.4 was found to be optimum. Well crystallised particles with approx. 6–12 nm size, narrow size distribution and cubo-spheroidal shape were synthesised. Particles were Superparamagnetic with high values of saturation magnetisation of up to 68 emu/g and negligible values of remanence and coercivity. A reaction yield of up to 62% was obtained. Hydrophilic coated particles were produced in a single, one step facile process for biomedical applications, using optimised parameters of pH and alkali concentration obtained in the study. Single domain particles with good magnetisation formed stable aqueous dispersions. FTIR, UV-Visible and DLS were used to confirm the coating and dispersion stabilities of the particles. These particles have the requisite properties required for application in different biomedical fields.

High-efficiency cavity-dumped micro-chip Yb:YAG laser

Science.gov (United States)

Nishio, M.; Maruko, A.; Inoue, M.; Takama, M.; Matsubara, S.; Okunishi, H.; Kato, K.; Kyomoto, K.; Yoshida, T.; Shimabayashi, K.; Morioka, M.; Inayoshi, S.; Yamagata, S.; Kawato, S.

2014-09-01

High-efficiency cavity-dumped ytterbium-doped yttrium aluminum garnet (Yb:YAG) laser was developed. Although the high quantum efficiency of ytterbium-doped laser materials is appropriate for high-efficiency laser oscillation, the efficiency is decreased by their quasi-three/four laser natures. High gain operation by high intensity pumping is suitable for high efficiency oscillation on the quasi-three/four lasers without extremely low temperature cooling. In our group, highest efficiency oscillations for continuous wave, nanosecond to picosecond pulse lasers were achieved at room temperature by the high gain operation in which pump intensities were beyond 100 kW/cm2.

Design of high-efficiency diffractive optical elements towards ultrafast mid-infrared time-stretched imaging and spectroscopy

Science.gov (United States)

Xie, Hongbo; Ren, Delun; Wang, Chao; Mao, Chensheng; Yang, Lei

2018-02-01

Ultrafast time stretch imaging offers unprecedented imaging speed and enables new discoveries in scientific research and engineering. One challenge in exploiting time stretch imaging in mid-infrared is the lack of high-quality diffractive optical elements (DOEs), which encode the image information into mid-infrared optical spectrum. This work reports the design and optimization of mid-infrared DOE with high diffraction-efficiency, broad bandwidth and large field of view. Using various typical materials with their refractive indices ranging from 1.32 to 4.06 in ? mid-infrared band, diffraction efficiencies of single-layer and double-layer DOEs have been studied in different wavelength bands with different field of views. More importantly, by replacing the air gap of double-layer DOE with carefully selected optical materials, one optimized ? triple-layer DOE, with efficiency higher than 95% in the whole ? mid-infrared window and field of view greater than ?, is designed and analyzed. This new DOE device holds great potential in ultrafast mid-infrared time stretch imaging and spectroscopy.

Experimental typing of the entry efficiency in calm air of an annular slot sampler; Determination experimentale de l'efficacite de captage en air calme d'un echantillonneur a fente annulaire

Energy Technology Data Exchange (ETDEWEB)

Roger, F.; Fabries, J.F.; Gorner, P.; Wrobel, R. [Institut National de Recherche et de Securite, INRS, Lab. de Metrologie de la Pollution par les Aerosols, 54 - Vandoeuvre-Les-Nancy (France); Renoux, A. [Paris-12 Univ., Lab. de Physique des Aerosols et de Transfert des Contaminations, 94 - Creteil (France)

2000-07-01

Aerosol sampling is a complex physical process that depends on many parameters like particle size, wind speed, aspiration velocity and sampler geometry. Inertia has a predominant influence on particle motion in moving air for particle size above 1 {mu}m. In calm air where air movement is mainly induced by the aspiration orifice of the sampler, gravitational settling affects more deeply particle motion and hence sampler performance. The entry efficiency of a sampler with an annular aspiration slot was recently measured for several conditions of aspiration flow rate, wind speed (1 and 3 m s{sup -1}) and geometric parameters of the sampler as a function of particle aerodynamic diameter. Some complementary work was carried out to add new experimental data corresponding to the same sampler in calm air. The results were obtained for 9 configurations, combining several values of disc diameter, aspiration slot width, and aspiration velocity. A semi-empirical model was developed from the data that enables the calculation of particle entry efficiency of the annular sampler in calm air. In addition, a numerical study was carried out to calculate the particle trajectories approaching the annular aspiration slot of the sampler. The results show that particle rebounds on the sampler walls have a significant effect on the entry efficiency of the sampler in calm air. (authors)

Performance of a hydraulic air compressor for use in compressed air energy storage power systems

Energy Technology Data Exchange (ETDEWEB)

Berghmans, J. A.; Ahrens, F. W.

1978-01-01

A fluid mechanical analysis of a hydraulic air compression system for Compressed Air Energy Storage (CAES) application is presented. With this compression concept, air is charged into an underground reservoir, for later use in power generation, by entraining bubbles into a downward flow of water from a surface reservoir. Upon releasing the air in the underground reservoir, the water is pumped back to the surface. The analytical model delineated is used to predict the hydraulic compressor performance characteristics (pumping power, pump head, compression efficiency) as a function of water flow rate and system geometrical parameters. The results indicate that, although large water pumps are needed, efficiencies as high as 90% (relative to ideal isothermal compression) can be expected. This should result in lower compression power than for conventional compressor systems, while eliminating the need for the usual intercoolers and aftercooler.

Influences of the Air in Metal Powder High Velocity Compaction

Directory of Open Access Journals (Sweden)

Liu Jun

2017-01-01

Full Text Available During the process of metal powder high velocity impact compaction, the air is compressed sharply and portion remains in the compacts. In order to study the Influences, a discrete density volleyball accumulation model for aluminium powder was established with the use of ABAQUS. Study found that the powder porosity air obstruct the pressing process because remaining air reduced strength and density of the compacts in the current high-speed pressing (V≤100m/s. When speed further increased (V≥100m/s, the temperature of the air increased sharply, and was even much higher than the melting point of the material. When aluminium powder was compressed at a speed of 200m/s, temperatures of air could reach 2033 K, far higher than the melting point of 877 K. Increased density of powders was a result of local softening and even melt adhesive while air between particles with high temperature and pressure flowed past.

Highly efficient high temperature electrolysis

DEFF Research Database (Denmark)

Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

2008-01-01

High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

High-Efficiency Glass and Printable Flexible Dye-Sensitized Solar Cells with Water-Based Electrolytes

Directory of Open Access Journals (Sweden)

Omar Moudam

2014-01-01

Full Text Available The performance of a flexible and glass dye-sensitized solar cell (DSSC with water-based electrolyte solutions is described. High concentrations of alkylamidazoliums were used to overcome the deleterious effect of water and, based on this variable, pure water-based electrolyte DSSCs were tested displaying the highest recorded efficiency so far of 3.45% and 6% for flexible and glass cells, respectively, under a simulated air mass 1.5 solar spectrum illumination at 100 mWcm−2. An improvement in the Jsc with high water content and the positive impact of GuSCN on the enhancement of the performance of pure water-based electrolytes were also observed.

Evaluation of physical sampling efficiency for cyclone-based personal bioaerosol samplers in moving air environments.

Science.gov (United States)

Su, Wei-Chung; Tolchinsky, Alexander D; Chen, Bean T; Sigaev, Vladimir I; Cheng, Yung Sung

2012-09-01

The need to determine occupational exposure to bioaerosols has notably increased in the past decade, especially for microbiology-related workplaces and laboratories. Recently, two new cyclone-based personal bioaerosol samplers were developed by the National Institute for Occupational Safety and Health (NIOSH) in the USA and the Research Center for Toxicology and Hygienic Regulation of Biopreparations (RCT & HRB) in Russia to monitor bioaerosol exposure in the workplace. Here, a series of wind tunnel experiments were carried out to evaluate the physical sampling performance of these two samplers in moving air conditions, which could provide information for personal biological monitoring in a moving air environment. The experiments were conducted in a small wind tunnel facility using three wind speeds (0.5, 1.0 and 2.0 m s(-1)) and three sampling orientations (0°, 90°, and 180°) with respect to the wind direction. Monodispersed particles ranging from 0.5 to 10 μm were employed as the test aerosols. The evaluation of the physical sampling performance was focused on the aspiration efficiency and capture efficiency of the two samplers. The test results showed that the orientation-averaged aspiration efficiencies of the two samplers closely agreed with the American Conference of Governmental Industrial Hygienists (ACGIH) inhalable convention within the particle sizes used in the evaluation tests, and the effect of the wind speed on the aspiration efficiency was found negligible. The capture efficiencies of these two samplers ranged from 70% to 80%. These data offer important information on the insight into the physical sampling characteristics of the two test samplers.

Controllable Growth of Perovskite Films by Room-Temperature Air Exposure for Efficient Planar Heterojunction Photovoltaic Cells.

Science.gov (United States)

Yang, Bin; Dyck, Ondrej; Poplawsky, Jonathan; Keum, Jong; Das, Sanjib; Puretzky, Alexander; Aytug, Tolga; Joshi, Pooran C; Rouleau, Christopher M; Duscher, Gerd; Geohegan, David B; Xiao, Kai

2015-12-01

A two-step solution processing approach has been established to grow void-free perovskite films for low-cost high-performance planar heterojunction photovoltaic devices. A high-temperature thermal annealing treatment was applied to drive the diffusion of CH3NH3I precursor molecules into a compact PbI2 layer to form perovskite films. However, thermal annealing for extended periods led to degraded device performance owing to the defects generated by decomposition of perovskite into PbI2. A controllable layer-by-layer spin-coating method was used to grow "bilayer" CH3NH3I/PbI2 films, and then drive the interdiffusion between PbI2 and CH3NH3I layers by a simple air exposure at room temperature for making well-oriented, highly crystalline perovskite films without thermal annealing. This high degree of crystallinity resulted in a carrier diffusion length of ca. 800 nm and a high device efficiency of 15.6%, which is comparable to values reported for thermally annealed perovskite films. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy Efficient Microlith-Based Catalytic Reactor and Recuperator for Air Quality Control Applications

Science.gov (United States)

Vilekar, Saurabh A.; Hawley, Kyle; Junaedi, Christian; Crowder, Bruce; Prada, Julian; Mastanduno, Richard; Perry, Jay L.; Kayatin, Matthew J.

2017-01-01

Precision Combustion, Inc. (PCI) and NASA’s Marshall Space Flight Center (MSFC) have been developing, characterizing, and optimizing high temperature catalytic oxidizers (HTCO) based on PCI’s patented Microlith technology to meet the requirements of future extended human spaceflight explorations. Previous efforts focused on integrating PCI’s HTCO unit with a compact, simple recuperative heat exchanger to reduce the overall system size and weight. Significant improvement was demonstrated over traditional approaches of integrating the HTCO with an external recuperative heat exchanger. While the critical target performance metrics were achieved, the thermal effectiveness of PCI’s recuperator remained a potential area of improvement to further reduce the energy requirements of the integrated system. Using the same material combinations and an improved recuperator design, the redesigned prototype has experimentally demonstrated 20 – 30% reduction (flow dependent) in steady state power consumption compared to the earlier prototype without compromising the destruction efficiency of methane and volatile organic compounds (VOCs). Moreover, design modifications and improvements allow our redesigned prototype to be more easily manufactured compared to traditional brazed plate-fin recuperator designs. The redesigned prototype was delivered to MSFC for validation testing. Here, we report and discuss the performance of the improved prototype HTCO unit with a high efficiency recuperative heat exchanger based on testing at PCI and MSFC. The device is expected to provide a reliable and robust means of disposing of trace levels of methane and VOCs by oxidizing them into carbon dioxide and water in order to maintain clean air in enclosed spaces, such as crewed spacecraft cabins.

Printed Self-Powered Miniature Air Sampling Sensors

Directory of Open Access Journals (Sweden)

Joseph Birmingham

2017-07-01

Full Text Available The recent geo-political climate has increased the necessity for autonomous, chip-sized, lightweight, air sampling systems which can quickly detect and characterize chemical, biological, radiological, nuclear, and high explosive (CBRNE hazardous materials and relay the results. To address these issues, we have developed a self-powered 3-D chip architecture that processes air to produce concentrated size- sorted particle (and vapor samples that could be integrated with on-chip nanoelectronic detectors for the discovery of weapons of mass destruction (WMD. The unique air movement approach is composed of a nanoscale energy harvester that provides electricity to a printed ion-drag pump to push air through coated-microstructured arrays. The self-powered microstructured array air sampler was designed using computational fluid dynamics (CFD modeling to collect particles from 1-10 microns at greater than 99.9999 % efficiency with less than 100 Pascal [Pa] pressure drop at a specified air flow rate. Surprisingly, even at minimum air flow rates below specifications, these CFD predictions were matched by experimental results gathered in a Government aerosol chamber. The microstructured array engineered filter equaled the collection capability of a membrane or a high efficiency particle air (HEPA filter at a fraction of the filter pressure drop.

Effect of the electrodynamic structure of a microwave discharge in air on the efficiency of oxygen dissociation

International Nuclear Information System (INIS)

Akhmedzhanov, R.A.; Vikharev, A.L.; Gorbachov, A.M.; Ivanov, O.A.; Kolysko, A.L.

1997-01-01

From experimental measurements and numerical calculations of oxygen dissociation in a nanosecond microwave (MW) discharge in air, the dependance is obtained of the energy cost for the production of an oxygen atom on the electrodynamic structure and parameters of the discharge. Oxygen dissociation is shown to be most efficient when high-power MW pulses are used. On the basis of numerical calculations of the energy cost for oxygen for dissociation in a MW discharge created at altitudes of the ozone layer in the earth's atmosphere, a conclusion is made about the possibility of using MW discharges for effective compensation of the ozone loss in a local ''oxide hole.''

Collector Efficiency in Downward-Type Internal-Recycle Solar Air Heaters with Attached Fins

Directory of Open Access Journals (Sweden)

Chii-Dong Ho

2013-10-01

Full Text Available The internal-recycle operation effect on collector efficiency in downward-type rectangular solar air heaters with attached fins is theoretically investigated. It is found that considerable collector efficiency is obtainable if the collector has attached fins and the operation is carried out with internal recycling. The recycling operation increases the fluid velocity to decrease the heat transfer resistance, compensating for the undesirable effect of decreasing the heat transfer driving force (temperature difference due to remixing. The attached fins provide an enlarged heat transfer area. The order of performance in a device of same size is: double pass with recycle and fins > double pass with recycle but without fins > single pass without recycle and fins.

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

Energy Technology Data Exchange (ETDEWEB)

Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Diddi, Saurabh [Bureau of Energy Efficiency, Government of India (India); Ahuja, Deepanshu [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Mukherjee, P. K. [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Walia, Archana [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States)

2016-06-01

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant,and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. The finding that significant efficiency improvement is cost effective from a consumer perspective is robust over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one-star level) should be evaluated rigorously considering significant benefits to consumers, energy security, and environment

Design and development of a low cost, high current density power supply for streamer free atmospheric pressure DBD plasma generation in air.

Science.gov (United States)

Jain, Vishal; Visani, Anand; Srinivasan, R; Agarwal, Vivek

2018-03-01

This paper presents a new power supply architecture for generating a uniform dielectric barrier discharge (DBD) plasma in air medium at atmospheric pressure. It is quite a challenge to generate atmospheric pressure uniform glow discharge plasma, especially in air. This is because air plasma needs very high voltage for initiation of discharge. If the high voltage is used along with high current density, it leads to the formation of streamers, which is undesirable for most applications like textile treatment, etc. Researchers have tried to generate high-density plasma using a RF source, nanosecond pulsed DC source, and medium frequency AC source. However, these solutions suffer from low current discharge and low efficiency due to the addition of an external resistor to control the discharge current. Moreover, they are relatively costly and bulky. This paper presents a new power supply configuration which is very compact and generates high average density (∼0.28 W/cm 2 ) uniform glow DBD plasma in air at atmospheric pressure. The efficiency is also higher as no external resistor is required to control the discharge current. An inherent feature of this topology is that it can drive higher current oscillations (∼50 A peak and 2-3 MHz frequency) into the plasma that damp out due to the plasma dissipation only. A newly proposed model has been used with experimental validation in this paper. Simulations and experimental validation of the proposed topology are included. Also, the application of the generated plasma for polymer film treatment is demonstrated.

A review on test procedure, energy efficiency standards and energy labels for room air conditioners and refrigerator-freezers

Energy Technology Data Exchange (ETDEWEB)

Mahlia, T.M.I.; Saidur, R. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2010-09-15

Air conditioners and refrigerator-freezers are major energy users in a household environment and hence efficiency improvement of these appliances can be considered as an important step to reduce their energy consumption along with environmental pollution prevention. Energy efficiency standards and labels are commonly used tools to reduce the energy uses for household appliances for many countries around the world. The first step towards adopting energy efficiency standards is to establish a test procedure for rating and testing of an appliance. It may be mentioned that an energy test procedure is the technical foundation for energy efficiency standards, energy labels, and other related programs. This paper reviews requirements and specifications of various international test standards for testing and rating of room air conditioners and refrigerators. A review on the development of the energy efficiency standards has been provided as well. Finally, energy labels that provide some useful information for identifying energy efficient products have been reviewed for these appliances. It may be stated that the review will be useful for the developing countries who wish to develop these energy savings strategies. It is also expected to be useful to revise the existing strategies for a few selected countries who already implemented these strategies earlier. (author)

Low air exchange rate causes high indoor radon concentration in energy-efficient buildings

International Nuclear Information System (INIS)

Vasilyev, A.V.; Yarmoshenko, I.V.; Zhukovsky, M.V.

2015-01-01

Since 1995, requirements on energy-efficient building construction were established in Russian Building Codes. In the course of time, utilisation of such technologies became prevailing, especially in multi-storey building construction. According to the results of radon survey in buildings constructed meeting new requirements on energy efficiency, radon concentration exceeds the average level in early-constructed buildings. Preponderance of the diffusion mechanism of radon entry in modern multi-storey buildings has been experimentally established. The experimental technique of the assessment of ventilation rate in dwellings under real conditions was developed. Based on estimates of average ventilation rate, it was approved that measures to increase energy efficiency lead to reduction in ventilation rate and accumulation of higher radon concentrations indoors. Obtained ventilation rate values have to be considered as extremely low. (authors)

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

New advances in wet scrubbing improvement efficiencies

Energy Technology Data Exchange (ETDEWEB)

Keen, A.R. [Altech Group, Toronto, ON (Canada)

2000-07-01

Wet scrubbing systems are the most versatile and cost efficient of all air pollution abatement technologies. This paper presented System REITHER{sup TM} which is a new generation of venturi scrubber. The advantages of this design are that it is simple and compact, has high removal efficiencies for sub-micron dusts or aerosols and it is flexible to handle any mass flow rate. It also provides high and constant reliability, is easy to control and has the potential to absorb gaseous pollutants. Another advantage is that it can handle corrosive streams through corrosion resistant materials. Innovations in wet scrubbing have made it possible to provide reliable and efficient separation of fine particles, corrosive aerosols and gases. New technology provides industrial engineers with a cost effective option when control air emissions is required. 1 fig.

Design of energy efficient ventilation and air-conditioning systems

CERN Document Server

Seppänen, Olli; Bertilsson, Thore; Maripuu, Mari-Liis; Lamy, Hervé; Vanden Borre, Alex

2012-01-01

This guidebook covers numerous system components of ventilation and air-conditioning systems and shows how they can be improved by applying the latest technology products. Special attention is paid to details, which are often overlooked in the daily design practice, resulting in poor performance of high quality products once they are installed in the building system.

Combined use of an electrostatic precipitator and a high-efficiency particulate air filter in building ventilation systems: Effects on cardiorespiratory health indicators in healthy adults.

Science.gov (United States)

Day, D B; Xiang, J; Mo, J; Clyde, M A; Weschler, C J; Li, F; Gong, J; Chung, M; Zhang, Y; Zhang, J

2018-05-01

High-efficiency particulate air (HEPA) filtration in combination with an electrostatic precipitator (ESP) can be a cost-effective approach to reducing indoor particulate exposure, but ESPs produce ozone. The health effect of combined ESP-HEPA filtration has not been examined. We conducted an intervention study in 89 volunteers. At baseline, the air-handling units of offices and residences for all subjects were comprised of coarse, ESP, and HEPA filtration. During the 5-week long intervention, the subjects were split into 2 groups, 1 with just the ESP removed and the other with both the ESP and HEPA removed. Each subject was measured for cardiopulmonary risk indicators once at baseline, twice during the intervention, and once 2 weeks after baseline conditions were restored. Measured indoor and outdoor PM 2.5 and ozone concentrations, coupled with time-activity data, were used to calculate exposures. Removal of HEPA filters increased 24-hour mean PM 2.5 exposure by 38 (95% CI: 31, 45) μg/m 3 . Removal of ESPs decreased 24-hour mean ozone exposure by 2.2 (2.0, 2.5) ppb. No biomarkers were significantly associated with HEPA filter removal. In contrast, ESP removal was associated with a -16.1% (-21.5%, -10.4%) change in plasma-soluble P-selectin and a -3.0% (-5.1%, -0.8%) change in systolic blood pressure, suggesting reduced cardiovascular risks. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

CERN Document Server

Kroepelin, H; Hoffmann, K-U

2013-01-01

Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

Exergetic performance evaluation of a single pass baffled solar air heater

International Nuclear Information System (INIS)

Sabzpooshani, M.; Mohammadi, K.; Khorasanizadeh, H.

2014-01-01

In this study, the exergetic performance of a baffled type solar air heater has been evaluated theoretically. A detailed parametric study was done to investigate the effect of variation of fin and baffle parameters, number of glass covers, bottom insulation thickness and inlet air temperature at different mass flow rates on the exergy efficiency. The results indicated that attaching fins and baffles at low mass flow rates can lead to noticeable enhancement of the exergy efficiency. The results revealed that the trend of variation of the energy and exergy efficiencies are not the same and the exergy efficiency is the chief criterion for performance evaluation. Increasing the baffles width, reducing the distance between baffles and increasing the number of fins are effective at low mass flow rates, but at high mass flow rates the inverse trend is observable, such that exergy efficiency reduces sharply. The results showed that exergy efficiency increases with increasing the solar radiation intensity. By adding the second glass cover the exergy efficiency enhances at low mass flow rates. Increasing the insulation thickness over an optimum value doesn't improve the exergy efficiency. Increasing the inlet air temperature increases the exergy efficiency especially at high mass flow rates. - Highlights: • We study the exergetic performance of an upward type baffled solar air heater. • The effect of several design parameters on the performance is investigated. • Exergetic performance is very sensitive to the variation of baffles parameters. • Adding fins and baffles and increasing their parameters are efficient at low m . . • At high m . increment of baffles parameters causes decline of the exergy efficiency

Evaluation of high frequency ghost cavitation emissions for two different seismic air-gun arrays using numerical modelling

Science.gov (United States)

Khodabandeloo, Babak; Landrø, Martin

2017-04-01

Sound is deployed by marine mammals for variety of vital purposes such as finding food, communication, echolocation, etc. On the other hand human activities generate underwater noise. One major type of acoustic source is marine seismic acquisition which is carried out to image layers beneath the seabed exploiting reflected acoustic and elastic waves. Air-gun arrays are the most common and efficient marine seismic sources. Field measurements using broad band hydrophones have revealed that acoustic energies emitted by air-gun arrays contains frequencies from a few Hz up to tens of kHz. Frequencies below 200 Hz benefit seismic imaging and the rest is normally considered as wasted energy. On the other hand, the high frequency range (above 200 Hz) overlaps with hearing curves of many marine mammals and especially toothed whales and may have an impact on their behavior. A phenomenon called ghost cavitation is recently recognized to be responsible for a major part of these high frequencies (> 5 kHz). Acoustic pressure waves of individual air guns reflected from sea surface can cause the hydrostatic pressure to drop towards zero close to the source array. In these regions there is a high probability for water vapor cavity growth and subsequent collapse. We have simulated ghost cavitation cloud using numerical modelling and the results are validated by comparing with field measurements. The model is used to compare the amount of high frequency noise due to ghost cavitation for two different air gun arrays. Both of the arrays have three subarrays but the array distance for the one with 2730 in3 air volume is 6 meters and for the slightly bigger array (3250 in3 in air volume) the subarrays are separated by 8 meters. Simulation results indicate that the second array, despite larger subarray distance, generates stronger ghost cavitation signal.

Highly-efficient, frequency-tripled Nd:YAG laser for spaceborne LIDARs

Science.gov (United States)

Treichel, R.; Hoffmann, H.-D.; Luttmann, J.; Morasch, V.; Nicklaus, K.; Wührer, C.

2017-11-01

For a spaceborne lidar a highly reliable, long living and efficient laser source is absolutely essential. Within the frame of the development of a laser source for the backscatter lidar ATLID, which will be flown on EarthCare mission, we setup and tested a predevelopment model of an injection-seeded, diode pumped, frequency tripled, pulsed high power Nd:YAG MOPA laser operating nominally at 100 Hz pulse repetition frequency. We also tested the burst operation mode. The excellent measured performance parameter will be introduced. The oscillator rod is longitudinally pumped from both sides. The oscillator has been operated with three cavity control methods: "Cavity Dither", "Pound-Drever-Hall" and "Adaptive Ramp & Fire". Especially the latter method is very suitable to operate the laser in harsh vibrating environment such in airplanes. The amplifier bases on the InnoSlab design concept. The constant keeping of a moderate fluence in the InnoSlab crystal permits excellent possibilities to scale the pulse energy to several 100 mJ. An innovative pump unit and optics makes the laser performance insensitive to inhomogeneous diode degradation and allows switching of additional redundant diodes. Further key features have been implemented in a FM design concept. The operational lifetime is extended by the implementation of internal redundancies for the most critical parts. The reliability is increased due to the higher margin onto the laser induced damage threshold by a pressurized housing. Additionally air-to-vacuum effects becomes obsolete. A high efficient heat removal concept has been implemented.

Prediction of flame formation in highly preheated air combustion

International Nuclear Information System (INIS)

Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool; Katsuki, Masashi

2008-01-01

Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

Prediction of flame formation in highly preheated air combustion

Energy Technology Data Exchange (ETDEWEB)

Yang, Jang Sik; Choi, Gyung Min; Kim, Duck Jool [Pusan National University, Busan (Korea, Republic of); Katsuki, Masashi [Osaka University, Osaka (Japan)

2008-11-15

Fundamental information about the ignition position and shape of a flame in highly preheated air combustion was obtained, and the suitability of the suggested reduced kinetic mechanism that reflects the characteristics of the highly preheated air combustion was demonstrated. Flame lift height and flame length with variations of premixed air temperature and oxygen concentration were measured by CH chemiluminescence intensity, and were computed with a reduced kinetic mechanism. Flame attached near a fuel nozzle started to lift when preheated air temperature became close to auto-ignition temperature and/or oxygen concentration reduced. The flame lift height increased but the flame length decreased with decreasing preheated air temperature and flame length reversed after a minimum value. Calculated results showed good agreement with those of experiment within tolerable error. Flame shape shifted from diffusion flame shape to partial premixed flame shape with increasing lift height and this tendency was also observed in the computation results

Technical and Economic Aspects of Designing an Efficient Room Air-Conditioner Program in India

Energy Technology Data Exchange (ETDEWEB)

Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.

2017-09-05

Several studies have projected a massive increase in the demand for air conditioners (ACs) over the next two decades in India. By 2030, room ACs could add 140 GW to the peak load, equivalent to over 30% of the total projected peak load. Therefore, there is significant interest among policymakers, regulators, and utilities in managing room AC demand by enhancing energy efficiency. Building on the historical success of the Indian Bureau of Energy Efficiency’s star-labeling program, Energy Efficiency Services Limited recently announced a program to accelerate the sale of efficient room ACs using bulk procurement, similar to their successful UJALA light-emitting diode (LED) bulk procurement program. This report discusses some of the key considerations in designing a bulk procurement or financial incentive program for enhancing room AC efficiency in India. We draw upon our previous research to demonstrate the overall technical potential and price impact of room AC efficiency improvement and its technical feasibility in India. We also discuss the importance of using low global warming potential (GWP) refrigerants and smart AC equipment that is demand response (DR) ready.

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

Energy Technology Data Exchange (ETDEWEB)

Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Diddi, Saurabh [Government of India, New Delhi (India). Bureau of Energy Efficiency; Ahuja, Deepanshu [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Mukherjee, P. K. [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Walia, Archana [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States)

2016-06-30

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. We assess several efficiency levels, two of which are summarized below in the report. The finding that significant efficiency improvement is cost effective from a consumer perspective is robust over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one star level) should be evaluated rigorously considering significant benefits to consumers, energy security and environment.

Low air exchange rate causes high indoor radon concentration in energy-efficient buildings.

Science.gov (United States)

Vasilyev, A V; Yarmoshenko, I V; Zhukovsky, M V

2015-06-01

Since 1995, requirements on energy-efficient building construction were established in Russian Building Codes. In the course of time, utilisation of such technologies became prevailing, especially in multi-storey building construction. According to the results of radon survey in buildings constructed meeting new requirements on energy efficiency, radon concentration exceeds the average level in early-constructed buildings. Preponderance of the diffusion mechanism of radon entry in modern multi-storey buildings has been experimentally established. The experimental technique of the assessment of ventilation rate in dwellings under real conditions was developed. Based on estimates of average ventilation rate, it was approved that measures to increase energy efficiency lead to reduction in ventilation rate and accumulation of higher radon concentrations indoors. Obtained ventilation rate values have to be considered as extremely low. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Advanced air distribution: Improving health and comfort while reducing energy use

DEFF Research Database (Denmark)

Melikov, Arsen Krikor

2015-01-01

-quality indoor environments at the same time as low-energy consumption. Advanced air distribution, designed to supply clean air where, when, and as much as needed, makes it possible to efficiently achieve thermal comfort, control exposure to contaminants, provide high-quality air for breathing and minimizing......Indoor environment affects the health, comfort, and performance of building occupants. The energy used for heating, cooling, ventilating, and air conditioning of buildings is substantial. Ventilation based on total volume air distribution in spaces is not always an efficient way to provide high...... the risk of airborne cross-infection while reducing energy use. This study justifies the need for improving the present air distribution design in occupied spaces, and in general the need for a paradigm shift from the design of collective environments to the design of individually controlled environments...

High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

CSIR Research Space (South Africa)

Boguslavsky, L

2010-10-01

Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

Efficiency of clay--TiO2 nanocomposites on the photocatalytic elimination of a model hydrophobic air pollutant.

Science.gov (United States)

Kibanova, Daria; Cervini-Silva, Javiera; Destaillats, Hugo

2009-03-01

Clay-supported TiO2 photocatalysts can potentially improve the performance of air treatment technologies via enhanced adsorption and reactivity of target volatile organic compounds (VOCs). In this study, a benchtop photocatalytic flow reactor was used to evaluate the efficiency of hectorite-TiO2 and kaolinite-TiO2, two novel composite materials synthesized in our laboratory. Toluene, a model hydrophobic VOC and a common indoor air pollutant, was introduced in the air stream at realistic concentrations, and reacted under UVA (lamda(max) = 365 nm) or UVC (lamda(max) = 254 nm) irradiation. The UVC lamp generated secondary emission at 185 nm, leading to the formation of ozone and other short-lived reactive species. Performance of clay-Ti02 composites was compared with that of pure TiO2 (Degussa P25), and with UV irradiation in the absence of photocatalyst under identical conditions. Films of clay-TiO2 composites and of P25 were prepared by a dip-coating method on the surface of Raschig rings, which were placed inside the flow reactor. An upstream toluene concentration of approximately 170 ppbv was generated by diluting a constant flow of toluene vapor from a diffusion source with dry air, or with humid air at 10, 33, and 66% relative humidity (RH). Toluene concentrations were determined by collecting Tenax-TA sorbent tubes downstream of the reactor, with subsequent thermal desorption--GC/MS analysis. The fraction of toluene removed, %R, and the reaction rate, Tr, were calculated for each experimental condition from the concentrations measured with and without UV irradiation. Use of UVC light (UV/TiO2/O3) led to overall higher reactivity, which can be partially attributed to the contribution of gas phase reactions by short-lived radical species. When the reaction rate was normalized to the light irradiance, Tr/Ilamda,the UV/TiO2 reaction under UVA irradiation was more efficient for samples with a higher content of TiO2 (P25 and Hecto-TiO2), but notfor Kao-TiO2. In all

New generation of one-dimensional photonic crystal cavities as robust high-efficient frequency converter

Science.gov (United States)

Parvini, T. S.; Tehranchi, M. M.; Hamidi, S. M.

2017-07-01

An effective method is proposed to design finite one-dimensional photonic crystal cavities (PhCCs) as robust high-efficient frequency converter. For this purpose, we consider two groups of PhCCs which are constructed by stacking m nonlinear (LiNbO3) and n linear (air) layers with variable thicknesses. In the first group, the number of linear layers is less than the nonlinear layers by one and in the second group by two. The conversion efficiency is calculated as a function of the arrangement and thicknesses of the linear and nonlinear layers by benefiting from nonlinear transfer matrix method. Our numerical simulations show that for each group of PhCCs, there is a structural formula by which the configurations with the highest efficiency can be constructed for any values of m and n (i.e. any number of layers). The efficient configurations are equivalent to Fabry-Pérot cavities that depend on the relationship between m and n and the mirrors in two sides of these cavities can be periodic or nonperiodic. The conversion efficiencies of these designed PhCCs are more than 5 orders of magnitude higher than the perfect ones which satisfy photonic bandgap edge and quasi-phase matching. Moreover, the results reveal that conversion efficiencies of Fabry-Pérot cavities with non-periodic mirrors are one order of magnitude higher than those with periodic mirrors. The major physical mechanisms of the enhancement are quasi-phase matching effect, cavity effect induced by dispersive mirrors, and double resonance for the pump and the harmonic fields in defect state. We believe that this method is very beneficial to the design of high-efficient compact optical frequency converters.

Nitrogen and Sulfur Co-doped Graphene Supported Cobalt Sulfide Nanoparticles as an Efficient Air Cathode for Zinc-air Battery

International Nuclear Information System (INIS)

Ganesan, Pandian; Ramakrishnan, Prakash; Prabu, Moni; Shanmugam, Sangaraju

2015-01-01

Highlights: • CoS 2 nanoparticles supported on a nitrogen and sulfur co-doped graphene oxide is described. • Improved round trip efficiency was observed for CoS 2 (400)/N,S-GO. • CoS 2 (400)/N,S-GO possess improved durability with low over-potential. • CoS 2 (400)/N,S-GO is a promising air cathode for zinc-air battery. - ABSTRACT: Zinc-air battery is considered as one of the promising energy storage devices due to their low cost, eco-friendly and safe. Here, we present a simple approach to the preparation of cobalt sulfide nanoparticles supported on a nitrogen and sulfur co-doped graphene oxide surface. Cobalt sulfide nanoparticles dispersed on graphene oxide hybrid was successfully prepared by solid state thermolysis approach at 400 °C, using cobalt thiourea and graphene oxide. X-ray diffraction study revealed that hybrid electrode prepared at 400 °C results in pure CoS 2 phase. The hybrid CoS 2 (400)/N,S-GO electrode exhibits low over-potential gap about 0.78 V vs. Zn after 70 cycles with remarkable and robust charge and discharge profile. And also the CoS 2 (400)/N,S-GO showing deep discharge behavior with stability up to 7.5 h.

Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

Science.gov (United States)

Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

2010-10-15

Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories. Copyright © 2010 Elsevier B.V. All rights

Design and cold-air test of single-stage uncooled turbine with high work output

Science.gov (United States)

Moffitt, T. P.; Szanca, E. M.; Whitney, W. J.; Behning, F. P.

1980-01-01

A solid version of a 50.8 cm single stage core turbine designed for high temperature was tested in cold air over a range of speed and pressure ratio. Design equivalent specific work was 76.84 J/g at an engine turbine tip speed of 579.1 m/sec. At design speed and pressure ratio, the total efficiency of the turbine was 88.6 percent, which is 0.6 point lower than the design value of 89.2 percent. The corresponding mass flow was 4.0 percent greater than design.

Efficient and stable CH3NH3PbI3-x(SCN)x planar perovskite solar cells fabricated in ambient air with low-temperature process

Science.gov (United States)

Zhang, Zongbao; Zhou, Yang; Cai, Yangyang; Liu, Hui; Qin, Qiqi; Lu, Xubing; Gao, Xingsen; Shui, Lingling; Wu, Sujuan; Liu, Jun-Ming

2018-02-01

Planar perovskite solar cells (PSCs) based on CH3NH3PbI3-x(SCN)x (SCN: thiocyanate) active layer and low-temperature processed TiO2 films are fabricated by a sequential two-step method in ambient air. Here, alkali thiocyanates (NaSCN, KSCN) are added into Pb(SCN)2 precursor to improve the microstructure of CH3NH3PbI3-x(SCN)x perovskite layers and performance of the as-prepared PSCs. At the optimum concentrations of alkali thiocyanates as additives, the as-prepared NaSCN-modified and KSCN-modified PSCs demonstrate the efficiencies of 16.59% and 15.63% respectively, being much higher than 12.73% of the reference PSCs without additives. This improvement is primarily ascribed to the enhanced electron transport, reduced recombination rates and much improved microstructures with large grain size and low defect density at grain boundaries. Importantly, it is revealed that the modified PSCs at the optimized concentrations of alkali thiocyanates additives exhibit remarkably improved stability than the reference PSCs against humid circumstance, and a continuous exposure to humid air without encapsulation over 45 days only records about 5% degradation of the efficiency. These findings provide a facile approach to fabricate efficient and stable PSCs by low processing temperature in ambient air, both of which are highly preferred for future practical applications of PSCs.

40 CFR 761.71 - High efficiency boilers.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false High efficiency boilers. 761.71... PROHIBITIONS Storage and Disposal § 761.71 High efficiency boilers. (a) To burn mineral oil dielectric fluid containing a PCB concentration of ≥50 ppm, but boiler shall comply with the following...

Unconventional, High-Efficiency Propulsors

DEFF Research Database (Denmark)

Andersen, Poul

1996-01-01

The development of ship propellers has generally been characterized by search for propellers with as high efficiency as possible and at the same time low noise and vibration levels and little or no cavitation. This search has lead to unconventional propulsors, like vane-wheel propulsors, contra-r...

Increasing energy efficiency by in-situ oxygen measurement in combustion gas and optimized fuel-air-ratio control; Effizienzsteigerung durch in-situ Sauerstoffmessung im Verbrennungsgas

Energy Technology Data Exchange (ETDEWEB)

Boltz, Yvonne [Marathon Sensors Inc., West Chester, OH (United States); Winter, Karl-Michael [PROCESS-ELECTRONIC GmbH, Heiningen (Germany)

2012-04-15

High energy costs as well as the necessity to minimize exhaust emissions require a most efficient usage of fossil primary energy resources. In heat treating but also in power generation natural gas is mostly used. Efficient burner systems and preheating combustion air using recuperators or regenerators minimize exhaust losses to a high extent. Another well known but seldom used optimization method controls the excess oxygen percentage in the exhaust gas. Already partially in use in households and state-of-the-art in the combustion control of car engines this technique is still not widely used in industrial sized systems. For closed burners there are few sensor options available that can be integrated into the burner. This article presents a variety of measuring and control systems that have been tailored to this particular task, able to increase the efficiency of both, existing older installations and new burner systems. (orig.)

Research & Implementation of AC - DC Converter with High Power Factor & High Efficiency

Directory of Open Access Journals (Sweden)

Hsiou-Hsian Nien

2014-05-01

Full Text Available In this paper, we design and develop a high power factor, high efficiency two-stage AC - DC power converter. This paper proposes a two-stage AC - DC power converter. The first stage is boost active power factor correction circuit. The latter stage is near constant frequency LLC resonant converter. In addition to traditional LLC high efficiency advantages, light-load conversion efficiency of this power converter can be improved. And it possesses high power factor and near constant frequency operating characteristics, can significantly reduce the electromagnetic interference. This paper first discusses the main structure and control manner of power factor correction circuit. And then by the LLC resonant converter equivalent model proceed to circuit analysis to determine the important parameters of the converter circuit elements. Then design a variable frequency resonant tank. The resonant frequency can change automatically on the basis of the load to reach near constant frequency operation and a purpose of high efficiency. Finally, actually design and produce an AC – DC power converter with output of 190W to verify the characteristics and feasibility of this converter. The experimental results show that in a very light load (9.5 W the efficiency is as high as 81%, the highest efficiency of 88% (90 W. Full load efficiency is 87%. At 19 W ~ 190 W power changes, the operating frequency change is only 0.4 kHz (AC 110 V and 0.3 kHz (AC 220 V.

Efficiency of poly-generating high temperature fuel cells

Energy Technology Data Exchange (ETDEWEB)

Margalef, Pere; Brown, Tim; Brouwer, Jacob; Samuelsen, Scott [National Fuel Cell Research Center (NFCRC), University of California, Irvine, CA 92697-3550 (United States)

2011-02-15

High temperature fuel cells can be designed and operated to poly-generate electricity, heat, and useful chemicals (e.g., hydrogen) in a variety of configurations. The highly integrated and synergistic nature of poly-generating high temperature fuel cells, however, precludes a simple definition of efficiency for analysis and comparison of performance to traditional methods. There is a need to develop and define a methodology to calculate each of the co-product efficiencies that is useful for comparative analyses. Methodologies for calculating poly-generation efficiencies are defined and discussed. The methodologies are applied to analysis of a Hydrogen Energy Station (H{sub 2}ES) showing that high conversion efficiency can be achieved for poly-generation of electricity and hydrogen. (author)

High efficiency, variable geometry, centrifugal cryogenic pump

International Nuclear Information System (INIS)

Forsha, M.D.; Nichols, K.E.; Beale, C.A.

1994-01-01

A centrifugal cryogenic pump has been developed which has a basic design that is rugged and reliable with variable speed and variable geometry features that achieve high pump efficiency over a wide range of head-flow conditions. The pump uses a sealless design and rolling element bearings to achieve high reliability and the ruggedness to withstand liquid-vapor slugging. The pump can meet a wide range of variable head, off-design flow requirements and maintain design point efficiency by adjusting the pump speed. The pump also has features that allow the impeller and diffuser blade heights to be adjusted. The adjustable height blades were intended to enhance the pump efficiency when it is operating at constant head, off-design flow rates. For small pumps, the adjustable height blades are not recommended. For larger pumps, they could provide off-design efficiency improvements. This pump was developed for supercritical helium service, but the design is well suited to any cryogenic application where high efficiency is required over a wide range of head-flow conditions

Analysis and Design Considerations of a High-Power Density, Dual Air Gap, Axial-Field Brushless, Permanent Magnet Motor.

Science.gov (United States)

Cho, Chahee Peter

1995-01-01

Until recently, brush dc motors have been the dominant drive system because they provide easily controlled motor speed over a wide range, rapid acceleration and deceleration, convenient control of position, and lower product cost. Despite these capabilities, the brush dc motor configuration does not satisfy the design requirements for the U.S. Navy's underwater propulsion applications. Technical advances in rare-earth permanent magnet materials, in high-power semiconductor transistor technology, and in various rotor position-sensing devices have made using brushless permanent magnet motors a viable alternative. This research investigates brushless permanent magnet motor technology, studying the merits of dual-air gap, axial -field, brushless, permanent magnet motor configuration in terms of power density, efficiency, and noise/vibration levels. Because the design objectives for underwater motor applications include high-power density, high-performance, and low-noise/vibration, the traditional, simplified equivalent circuit analysis methods to assist in meeting these goals were inadequate. This study presents the development and verification of detailed finite element analysis (FEA) models and lumped parameter circuit models that can calculate back electromotive force waveforms, inductance, cogging torque, energized torque, and eddy current power losses. It is the first thorough quantification of dual air-gap, axial -field, brushless, permanent magnet motor parameters and performance characteristics. The new methodology introduced in this research not only facilitates the design process of an axial field, brushless, permanent magnet motor but reinforces the idea that the high-power density, high-efficiency, and low-noise/vibration motor is attainable.

Photocatalytic organic transformation by layered double hydroxides: highly efficient and selective oxidation of primary aromatic amines to their imines under ambient aerobic conditions.

Science.gov (United States)

Yang, Xiu-Jie; Chen, Bin; Li, Xu-Bing; Zheng, Li-Qiang; Wu, Li-Zhu; Tung, Chen-Ho

2014-06-25

We report the first application of layered double hydroxide as a photocatalyst in the transformation of primary aromatic amines to their corresponding imines with high efficiency and selectivity by using oxygen in an air atmosphere as a terminal oxidant under light irradiation.

Does regulation stimulate productivity? The effect of air quality policies on the efficiency of US power plants

International Nuclear Information System (INIS)

Fleishman, Rachel; Alexander, Rob; Bretschneider, Stuart; Popp, David

2009-01-01

This research examines the effect of air quality regulations on the productivity of US power plants based on both economic and environmental outputs. Using data envelopment analysis (DEA) to estimate an efficiency measure incorporating both economic and environmental outcomes, we look at changes in efficiency in US power plants over an eleven-year time period (1994-2004) during which several different regulations were implemented for the control of nitrogen oxides (NO x ) and sulfur dioxide (SO 2 ). The paper then models how estimated efficiency behaves over time as a function of regulatory changes. Findings suggest mixed effects of regulations on power plant efficiency when pollution abatement and electricity generation are both included as outputs.

Plasma gasification process: Modeling, simulation and comparison with conventional air gasification

International Nuclear Information System (INIS)

Janajreh, Isam; Raza, Syed Shabbar; Valmundsson, Arnar Snaer

2013-01-01

Highlights: ► Plasma/conventional gasification are modeled via Gibbs energy minimization. ► The model is applied to wide range of feedstock, tire, biomass, coal, oil shale. ► Plasma gasification show high efficiency for tire waste and coal. ► Efficiency is around 42% for plasma and 72% for conventional gasification. ► Lower plasma gasification efficiency justifies hazardous waste energy recovery. - Abstract: In this study, two methods of gasification are developed for the gasification of various feedstock, these are plasma gasification and conventional air gasification. The two methods are based on non-stoichiometric Gibbs energy minimization approach. The model takes into account the different type of feedstocks, which are analyzed at waste to energy lab at Masdar Institute, oxidizer used along with the plasma energy input and accurately evaluates the syngas composition. The developed model is applied for several types of feedstock, i.e. waste tire material, coal, plywood, pine needles, oil shale, and municipal solid waste (MSW), algae, treated/untreated wood, instigating air/steam as the plasma gas and only air as oxidizer for conventional gasification. The results of plasma gasification and conventional air gasification are calculated on the bases of product gas composition and the process efficiency. Results of plasma gasification shows that high gasification efficiency is achievable using both tire waste material and coal, also, the second law efficiency is calculated for plasma gasification that shows a relative high efficiency for tire and coal as compare to other feedstock. The average process efficiency for plasma gasification is calculated to be around 42%. On other hand the result of conventional gasification shows an average efficiency of 72%. The low efficiency of plasma gasification suggest that if only the disposal of hazard waste material is considered then plasma gasification can be a viable option to recover energy.

Boost Converter Fed High Performance BLDC Drive for Solar PV Array Powered Air Cooling System

Directory of Open Access Journals (Sweden)

Shobha Rani Depuru

2017-01-01

Full Text Available This paper proposes the utilization of a DC-DC boost converter as a mediator between a Solar Photovoltaic (SPV array and the Voltage Source Inverters (VSI in an SPV array powered air cooling system to attain maximum efficiency. The boost converter, over the various common DC-DC converters, offers many advantages in SPV based applications. Further, two Brushless DC (BLDC motors are employed in the proposed air cooling system: one to run the centrifugal water pump and the other to run a fan-blower. Employing a BLDC motor is found to be the best option because of its top efficiency, supreme reliability and better performance over a wide range of speeds. The air cooling system is developed and simulated using the MATLAB/Simulink environment considering the steady state variation in the solar irradiance. Further, the efficiency of BLDC drive system is compared with a conventional Permanent Magnet DC (PMDC motor drive system and from the simulated results it is found that the proposed system performs better.

Multi-stage combustion using nitrogen-enriched air

Science.gov (United States)

Fischer, Larry E.; Anderson, Brian L.

2004-09-14

Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

HIGH EFFICIENCY TURBINE

OpenAIRE

VARMA, VIJAYA KRUSHNA

2012-01-01

Varma designed ultra modern and high efficiency turbines which can use gas, steam or fuels as feed to produce electricity or mechanical work for wide range of usages and applications in industries or at work sites. Varma turbine engines can be used in all types of vehicles. These turbines can also be used in aircraft, ships, battle tanks, dredgers, mining equipment, earth moving machines etc, Salient features of Varma Turbines. 1. Varma turbines are simple in design, easy to manufac...

Ultra High Efficiency ESP for Fine Particulate and Air Toxics Control

International Nuclear Information System (INIS)

Srinivasachar, Srivats; Pease, Benjamin R.; Porle, Kjell; Mauritzson, Christer; Haythornthwaite, Sheila

1997-01-01

Nearly ninety percent of U.S. coal-fired utility boilers are equipped with electrostatic precipitators (ESP). Cost effective retrofittable ESP technologies are the only means to accomplish Department of Energy's (DOE) goal of a major reduction in fine particulate and air toxic emissions from coal-fired power plants. Particles in the size range of 0.1 to 5 (micro)m typically escape ESPs. Metals, such as arsenic, cadmium, lead, molybdenum and antimony, concentrate on these particles. This is the main driver for improved fine particulate control. Vapor phase emissions of mercury, selenium and arsenic are also of major concern. Current dry ESPs, which operate at temperatures greater than 280 F, provide little control for vapor phase toxics. The need for inherent improvement to ESPs has to be considered keeping in perspective the current trend towards the use of low sulfur coals. Switching to low sulfur coals is the dominant approach for SO 2 emission reduction in the utility industry. Low sulfur coals generate high resistivity ash, which can cause an undesirable phenomenon called ''back corona.'' Higher particulate emissions occur if there is back corona in the ESP. Results of the pilot-scale testing identified the ''low temperature ESP'' concept to have the biggest impact for the two low sulfur coals investigated. Lowering the flue gas temperature to 220 F provided the maximum impact in terms of decreased emissions. Intermediate operating temperatures (reduction from 340 to 270 F) also gave significant ESP performance improvement. A significant reduction in particulate emissions was also noted when the flue gas humidity was increased (temperature held constant) from the baseline condition for these moderately high resistivity ash coals. Independent control of flue gas humidity and temperature was an important and a notable element in this project. Mercury emissions were also measured as a function of flue gas temperature. Mercury emissions decreased as the flue gas

Application of Cascade Refrigeration System with Mixing Refrigerant in Cold Air Cutting

Science.gov (United States)

Yang, Y.; Tong, M. W.; Yang, G.; Wang, X. P.

In the mechanical cutting process, the replacement of traditional cutting solution with cold air can avoid the pollution of environment. In order to high efficient the refrigerating device and flexible adjust the temperature of cold air, it is necessary to use cascade refrigeration system to supply cool quantity for the compressed air. The introduction of a two-component non-azeotropic mixing refrigerant into the cryogenic part of the cascade system, can effectively solve the problems of the system working at too high pressure and the volume expanding of refrigerant in case of the cascade refrigeration sets closed down. However, the filling ratio of mixing refrigerants impact on the relationships among the closing down pressure, refrigerating output and refrigerating efficiency. On the basis of computing and experiment, the optimal mixing ratio of refrigerant R22/R13 and a low temperature of -60° were obtained in this study. A cold air injecting device possessing high efficiency in energy saving has also been designed and manufactured. The cold air, generated from this cascade system and employed in a cutting process, takes good comprehensive effects on machining and cutting.

Flexible high power-per-weight perovskite solar cells with chromium oxide-metal contacts for improved stability in air

Science.gov (United States)

Kaltenbrunner, Martin; Adam, Getachew; Głowacki, Eric Daniel; Drack, Michael; Schwödiauer, Reinhard; Leonat, Lucia; Apaydin, Dogukan Hazar; Groiss, Heiko; Scharber, Markus Clark; White, Matthew Schuette; Sariciftci, Niyazi Serdar; Bauer, Siegfried

2015-10-01

Photovoltaic technology requires light-absorbing materials that are highly efficient, lightweight, low cost and stable during operation. Organolead halide perovskites constitute a highly promising class of materials, but suffer limited stability under ambient conditions without heavy and costly encapsulation. Here, we report ultrathin (3 μm), highly flexible perovskite solar cells with stabilized 12% efficiency and a power-per-weight as high as 23 W g-1. To facilitate air-stable operation, we introduce a chromium oxide-chromium interlayer that effectively protects the metal top contacts from reactions with the perovskite. The use of a transparent polymer electrode treated with dimethylsulphoxide as the bottom layer allows the deposition--from solution at low temperature--of pinhole-free perovskite films at high yield on arbitrary substrates, including thin plastic foils. These ultra-lightweight solar cells are successfully used to power aviation models. Potential future applications include unmanned aerial vehicles--from airplanes to quadcopters and weather balloons--for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.

GUIDE TO CALCULATING TRANSPORT EFFICIENCY OF AEROSOLS IN OCCUPATIONAL AIR SAMPLING SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Hogue, M.; Hadlock, D.; Thompson, M.; Farfan, E.

2013-11-12

This report will present hand calculations for transport efficiency based on aspiration efficiency and particle deposition losses. Because the hand calculations become long and tedious, especially for lognormal distributions of aerosols, an R script (R 2011) will be provided for each element examined. Calculations are provided for the most common elements in a remote air sampling system, including a thin-walled probe in ambient air, straight tubing, bends and a sample housing. One popular alternative approach would be to put such calculations in a spreadsheet, a thorough version of which is shared by Paul Baron via the Aerocalc spreadsheet (Baron 2012). To provide greater transparency and to avoid common spreadsheet vulnerabilities to errors (Burns 2012), this report uses R. The particle size is based on the concept of activity median aerodynamic diameter (AMAD). The AMAD is a particle size in an aerosol where fifty percent of the activity in the aerosol is associated with particles of aerodynamic diameter greater than the AMAD. This concept allows for the simplification of transport efficiency calculations where all particles are treated as spheres with the density of water (1g cm-3). In reality, particle densities depend on the actual material involved. Particle geometries can be very complicated. Dynamic shape factors are provided by Hinds (Hinds 1999). Some example factors are: 1.00 for a sphere, 1.08 for a cube, 1.68 for a long cylinder (10 times as long as it is wide), 1.05 to 1.11 for bituminous coal, 1.57 for sand and 1.88 for talc. Revision 1 is made to correct an error in the original version of this report. The particle distributions are based on activity weighting of particles rather than based on the number of particles of each size. Therefore, the mass correction made in the original version is removed from the text and the calculations. Results affected by the change are updated.

Security of bottle to fill in a high pressure air

Science.gov (United States)

Todic, M.; Latinovic, T.; Golubovic-Bugarski, V.; Majstorovic, A.

2018-01-01

Charging the bottle of high pressure air isolation devices is performed by a high-pressure compressor. The charging time is in function of the compressor capacity and the intensity of the nominal pressure of the air in the bottle. However, in accident situations this time is long and therefore high-pressure accumulators are used where the filling time of the bottle of isolation apparatus has been drastically reduced. Due to the short filling time of the bottle through the air flow, there is a thermodynamic load of bottle material that could endanger the safety of users and other participants in the area. It is therefore necessary to determine the critical parameters of the rapid charge and their intensity.

Affordable Energy-Efficient New Housing Solutions

Energy Technology Data Exchange (ETDEWEB)

Chandra, Subrato; Widder, Sarah H.; Bartlett, Rosemarie; McIlvaine, Janet; Chasar, David; Beal, David; Sutherland, Karen; Abbott, , K.; Fonorow, Ken; Eklund, Ken; Lubliner, Michael; Salzberg, Emily; Peeks, B.; Hewes, T.; Kosar, D.

2012-05-31

Since 2010, the U.S. Department of Energy’s Building America has sponsored research at PNNL to investigate cost-effective, energy-saving home-building technologies and to demonstrate how high-performance homes can deliver lower utility bills, increased comfort, and improved indoor air quality, while maintaining accessibility for low-income homeowners. PNNL and its contractors have been investigating 1) cost-effective whole-house solutions for Habitat for Humanity International (HFHI) and specific HFH affiliates in hot-humid and marine climates; 2) cost-effective energy-efficiency improvements for heating, ventilation, and air-conditioning (HVAC) systems in new, stick-built and manufactured homes; and 3) energy-efficient domestic hot-water systems.

Gamma-ray spectrometer system with high efficiency and high resolution

International Nuclear Information System (INIS)

Moss, C.E.; Bernard, W.; Dowdy, E.J.; Garcia, C.; Lucas, M.C.; Pratt, J.C.

1983-01-01

Our gamma-ray spectrometer system, designed for field use, offers high efficiency and high resolution for safeguards applications. The system consists of three 40% high-purity germanium detectors and a LeCroy 3500 data acquisition system that calculates a composite spectrum for the three detectors. The LeCroy 3500 mainframe can be operated remotely from the detector array with control exercised through modems and the telephone system. System performance with a mixed source of 125 Sb, 154 Eu, and 155 Eu confirms the expected efficiency of 120% with the overall resolution showing little degradation over that of the worst detector

High voltage generator circuit with low power and high efficiency applied in EEPROM

International Nuclear Information System (INIS)

Liu Yan; Zhang Shilin; Zhao Yiqiang

2012-01-01

This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM). The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique. The high efficiency is dependent on the zero threshold voltage (V th ) MOSFET and the charge transfer switch (CTS) charge pump. The proposed high voltage generator circuit has been implemented in a 0.35 μm EEPROM CMOS process. Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits. This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation. (semiconductor integrated circuits)

The effect of varying air injection rates on tall oil soap skimming efficiency for low fatty acid/resin acid ratio soaps produced by pulping mountain pine beetle-infected wood

Energy Technology Data Exchange (ETDEWEB)

Uloth, V.; Guy, E. [FPInnovations, Prince George, BC (Canada). PAPRICAN Div.

2009-07-01

This study was conducted to assess the impact of higher air injection rates on the skimmer performance of an evaporator soap skimmer at a mill in British Columbia (BC). Tests previously indicated that only 13 to 38 percent of the total soap in the feed liquor was skimmed for low acid number and low fatty acid and resin acid ratio soaps. A 2-day trial demonstrated that there were extended periods when soap skimming stopped completely and soap levels in the liquor equalled or exceeded levels observed in the feed liquor. Higher air injection rates had little impact on soap-skimming efficiency. The higher air injection rates decreased soap density by approximately 8 percent, and increased black liquor entrainment in the skimmed soap by approximately 35 percent. The use of higher air injection rates was not recommended, as high percentages of black liquor are known to cause high H{sub 2}S emissions during soap acidulation. 16 refs., 1 tab., 5 figs.

Destratification efficiency by hypolimnitic water lifter with air bullets. Kihodan wo mochiita shinsosui yosui shisetsu ni yoru mitsudo seiso no kongo koritsu

Energy Technology Data Exchange (ETDEWEB)

Ikeda, H; Suga, K [Utsunomiya University, Tochigi (Japan). Faculty of Engineering; Asaeda, T [Saitama University, Saitama (Japan). Faculty of Engineering

1994-02-21

The intermittent aeration and circulation method is used frequently to destruct temperature stratification in a reservoir to prevent it from eutrophication. This method uses a cylinder erected in water, into which air bullets are shot out intermittently to circulate and mix heavier water mass upward. The present study has performed numerical analysis on the process to mix density stratifications by operating an intermittent water lifter cylinder for an extended period of time, and discussed responses of each factor to variation. The numerical computation has been carried out according to the equation of motion for water and air in the water lifter cylinder, and the numerical model that hypothesizes the double plume after air bubbles have departed from the water lifter cylinder. The result indicated that the amount of hypolimnitic water lifted against the amount of air injected can be expressed by an empirical formula that uses only the relative air bullet volumes. An evaluation formula for the water lifting efficiency has also been derived. It has been found for the stratification mixing that trends in the mixing efficiency can be identified by two parameters of dimensionless air bubble amount and stratification strength. 17 refs., 11 figs., 4 tabs.

Research and development of a high efficiency gas-fired water heater. Volume 2. Task reports

Energy Technology Data Exchange (ETDEWEB)

Vasilakis, A.D.; Pearson, J.F.; Gerstmann, J.

1980-01-01

Design and development of a cost-effective high efficiency gas-fired water heater to attain a service efficiency of 70% (including the effect of exfiltration) and a service efficiency of 78% (excluding exfiltration) for a 75 GPD draw at a 90/sup 0/F temperature rise, with a stored water to conditioned air temperature difference of 80/sup 0/F, are described in detail. Based on concept evaluation, a non-powered natural draft water heater was chosen as the most cost-effective design to develop. The projected installed cost is $374 compared to $200 for a conventional unit. When the project water heater is compared to a conventional unit, it has a payback of 3.7 years and life cycle savings of $350 to the consumer. A prototype water heater was designed, constructed, and tested. When operated with sealed combustion, the unit has a service efficiency of 66.4% (including the effect of exfiltration) below a burner input of 32,000 Btu/h. In the open combustion configuration, the unit operated at a measured efficiency of 66.4% Btu/h (excluding exfiltration). This compares with a service efficiency of 51.3% for a conventional water heater and 61% for a conventional high efficiency unit capable of meeting ASHRAE 90-75. Operational tests showed the unit performed well with no evidence of stacking or hot spots. It met or exceeded all capacity or usage tests specified in the program test plan and met all emission goals. Future work will concentrate on designing, building, and testing pre-production units. It is anticipated that both sealed combustion and open draft models will be pursued.

Gold nanoparticles supported on titanium dioxide: an efficient catalyst for highly selective synthesis of benzoxazoles and benzimidazoles.

Science.gov (United States)

Tang, Lin; Guo, Xuefeng; Yang, Yu; Zha, Zhenggen; Wang, Zhiyong

2014-06-11

A highly efficient and selective reaction for the synthesis of 2-substituted benzoxazoles and benzimidazoles catalyzed by Au/TiO2 has been developed via two hydrogen-transfer processes. This reaction has a good tolerance to air and water, a wide substrate scope, and represents a new avenue for practical C-N and C-O bond formation. More importantly, no additional additives, oxidants and reductants are required for the reaction and the catalyst can be recovered and reused readily.

Energy Efficiency Analysis of Discharge Modes of an Adiabatic Compressed Air Energy Storage System

OpenAIRE

Shane D. Inder; Mehrdad Khamooshi

2017-01-01

Efficient energy storage is a crucial factor in facilitating the uptake of renewable energy resources. Among the many options available for energy storage systems required to balance imbalanced supply and demand cycles, compressed air energy storage (CAES) is a proven technology in grid-scale applications. This paper reviews the current state of micro scale CAES technology and describes a micro-scale advanced adiabatic CAES (A-CAES) system, where heat generated during compression is stored fo...

Achievement report for fiscal 1998 on development of environmentally friendly high-efficiency energy utilization system. 2. Research of technology of effectively utilizing high-efficiency energy / research of optimum system designing technology; 1998 nendo kankyo chowagata kokoritsu energy riyo system kaihatsu. 2. Kokoritsu energy yuko riyo gijutsu no kenkyu, saiteki system sekkei gijutsu no kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-05-01

This 2nd volume deals with the transportation and storage of energy in the above-named research. In search of technologies for transporting exhausted heat from the industrial area to the urban section for consumers to utilize the heat for driving their air-conditioners and hot water supply systems, the decomposition and composition reactions of methanol are utilized for a long-range transportation system. The subjects taken up in this connection include the research and development of a methanol energy system, non-equilibrium high-efficiency methanol decomposition technology, multifunctional catalysts, and highly active/selective catalysts capable of promoting reversible endoergic/exoergic reactions. Research and development is also conducted of a high-efficiency heat pump technology using hydrogen-absorbing alloys, and such a pump will realize an air-conditioning system not dependent on chlorofluorocarbon. In the research and development of a long-range heat transportation system using hydrogen-absorbing alloys, a study is made of technologies of heat/hydrogen recovery, transportation, and utilization. (NEDO)

Efficiency at Sorting Cards in Compressed Air

Science.gov (United States)

Poulton, E. C.; Catton, M. J.; Carpenter, A.

1964-01-01

At a site where compressed air was being used in the construction of a tunnel, 34 men sorted cards twice, once at normal atmospheric pressure and once at 3½, 2½, or 2 atmospheres absolute pressure. An additional six men sorted cards twice at normal atmospheric pressure. When the task was carried out for the first time, all the groups of men performing at raised pressure were found to yield a reliably greater proportion of very slow responses than the group of men performing at normal pressure. There was reliably more variability in timing at 3½ and 2½ atmospheres absolute than at normal pressure. At 3½ atmospheres absolute the average performance was also reliably slower. When the task was carried out for the second time, exposure to 3½ atmospheres absolute pressure had no reliable effect. Thus compressed air affected performance only while the task was being learnt; it had little effect after practice. No reliable differences were found related to age, to length of experience in compressed air, or to the duration of the exposure to compressed air, which was never less than 10 minutes at 3½ atmospheres absolute pressure. PMID:14180485

Considerations on the application in supermarkets. The high performance air cooler in the course of time; Ueberlegungen fuer die Anwendung im Supermarkt. Der Hochleistungsluftkuehler im Wandel der Zeit

Energy Technology Data Exchange (ETDEWEB)

Lich, Mathias [GEA Kueba GmbH, Baierbrunn (Germany)

2011-08-15

In the last twenty years, the high performant air cooler has undergone a rapid development. Power, energy efficiency and compact size an important role in the selection for the application in the supermarket. The development of the technology of EC fans shows that there always are potentials for an optimal development of products. While an air cooler needed a current consumption of 180 W for the fan twenty years ago, now significantly less than 100 W are necessary. Fan diameter, pipe diameter, shell size and all incorporated components have become more powerful and more efficient.

Development and characterization of high-efficiency, high-specific impulse xenon Hall thrusters

Science.gov (United States)

Hofer, Richard Robert

This dissertation presents research aimed at extending the efficient operation of 1600 s specific impulse Hall thruster technology to the 2000--3000 s range. While recent studies of commercially developed Hall thrusters demonstrated greater than 4000 s specific impulse, maximum efficiency occurred at less than 3000 s. It was hypothesized that the efficiency maximum resulted as a consequence of modern magnetic field designs, optimized for 1600 s, which were unsuitable at high-specific impulse. Motivated by the industry efforts and mission studies, the aim of this research was to develop and characterize xenon Hall thrusters capable of both high-specific impulse and high-efficiency operation. The research divided into development and characterization phases. During the development phase, the laboratory-model NASA-173M Hall thrusters were designed with plasma lens magnetic field topographies and their performance and plasma characteristics were evaluated. Experiments with the NASA-173M version 1 (v1) validated the plasma lens design by showing how changing the magnetic field topography at high-specific impulse improved efficiency. Experiments with the NASA-173M version 2 (v2) showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. Between 300--1000 V, total specific impulse and total efficiency of the NASA-173Mv2 operating at 10 mg/s ranged from 1600--3400 s and 51--61%, respectively. Comparison of the thrusters showed that efficiency can be optimized for specific impulse by varying the plasma lens design. During the characterization phase, additional plasma properties of the NASA-173Mv2 were measured and a performance model was derived accounting for a multiply-charged, partially-ionized plasma. Results from the model based on experimental data showed how efficient operation at high-specific impulse was enabled through regulation of the electron current with the magnetic field. The

Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

Energy Technology Data Exchange (ETDEWEB)

Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

2014-09-01

Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by first overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.

High Performance Cathodes for Li-Air Batteries

Energy Technology Data Exchange (ETDEWEB)

Xing, Yangchuan

2013-08-22

The overall objective of this project was to develop and fabricate a multifunctional cathode with high activities in acidic electrolytes for the oxygen reduction and evolution reactions for Li-air batteries. It should enable the development of Li-air batteries that operate on hybrid electrolytes, with acidic catholytes in particular. The use of hybrid electrolytes eliminates the problems of lithium reaction with water and of lithium oxide deposition in the cathode with sole organic electrolytes. The use of acid electrolytes can eliminate carbonate formation inside the cathode, making air breathing Li-air batteries viable. The tasks of the project were focused on developing hierarchical cathode structures and bifunctional catalysts. Development and testing of a prototype hybrid Li-air battery were also conducted. We succeeded in developing a hierarchical cathode structure and an effective bifunctional catalyst. We accomplished integrating the cathode with existing anode technologies and made a pouch prototype Li-air battery using sulfuric acid as catholyte. The battery cathodes contain a nanoscale multilayer structure made with carbon nanotubes and nanofibers. The structure was demonstrated to improve battery performance substantially. The bifunctional catalyst developed contains a conductive oxide support with ultra-low loading of platinum and iridium oxides. The work performed in this project has been documented in seven peer reviewed journal publications, five conference presentations, and filing of two U.S. patents. Technical details have been documented in the quarterly reports to DOE during the course of the project.

The Texas Air Quality Study: State of the Science of Ozone and Particulate Matter formation in Texas and Implications for Air Quality Policy

Science.gov (United States)

Allen, D. T.

2002-05-01

The Texas Air Quality Study (TexAQS) was performed during August and September of 2000; approximately 300 investigators from around the world made measurements of air pollutant concentrations and meteorological variables in southeast Texas. Five aircraft were deployed; five major ground chemistry sites were established and approximately 20 peripheral sites were established for collecting additional meteorological and chemical data. The scope, goals and preliminary results are available at the study web sites (www.utexas.edu/research/ceer/texaqs and www.utexas.edu/research/ceer/texaqsarchive). This presentation will provide an overview of the main findings from the study and will describe the role that ongoing data analysis activities are having on the development of air quality policy in the State of Texas. Some of the major findings are: Finding 1. Almost without exception, air parcels with very high ozone concentrations, observed by aircraft during the Texas Air Quality Study, had back trajectories that indicated a substantial contribution of emissions from industrial source regions. These air parcels also had chemical compositions that were representative of industrial sources, rather than typical urban sources. Finding 2: The rate of ozone production in and around the industrial source dominated areas in Houston can be very high, commonly exceeding 50 ppb/hr, and at times approaching instantaneous rates of 200 ppb/hr. Finding 3: The efficiency of ozone production in and around the industrial source dominated areas in Houston can be very high, ranging from 10-20 molecules of ozone per molecule of reacted NOx. Finding 4. Ozone production in the Houston urban plume was found to be slower and less efficient than in the composite industrial plume from the Ship Channel region and in plumes from isolated petrochemical facilities. Finding 5. The high rates and high efficiencies of ozone production in the industrial plumes are driven by high concentrations of reactive

Enhancing the Light-Extraction Efficiency of AlGaN Nanowires Ultraviolet Light-Emitting Diode by using Nitride/Air Distributed Bragg Reflector Nanogratings

KAUST Repository

Alias, Mohd Sharizal; Janjua, Bilal; Zhao, Chao; Priante, Davide; Alhamoud, Abdullah A.; Tangi, Malleswararao; Alanazi, Lafi M.; Alatawi, Abdullah A.; Albadri, Abdulrahman M.; Alyamani, Ahmed Y.; Ng, Tien Khee; Ooi, Boon S.

2017-01-01

The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction efficiency (LEE) due to the intrinsic material properties of AlGaN. Here, to enhance the LEE of the device, we demonstrate an AlGaN nanowires light-emitting diode (NWs-LED) integrated with nitride/air Distributed Bragg Reflector (DBR) nanogratings. Compared to a control device (only mesa), the AlGaN NWs-LED with the nitride/air DBR nanogratings exhibit enhancement in the light output power and external quantum efficiency (EQE) by a factor of ∼1.67. The higher light output power and EQE are attributed mainly to the multiple reflectances laterally for the transverse magnetic (TM)-polarized light and scattering introduced by the nanogratings. To further understand the LEE enhancement, the electrical field distribution, extraction ratio and polar pattern of the AlGaN NWs-LED with and without the nitride/air DBR nanogratings were analyzed using the finite-difference-time-domain method. It was observed that the TM-field emission was confined and scattered upward whereas the polar pattern was intensified for the AlGaN NWs-LED with the nanogratings. Our approach to enhance the LEE via the nitride/air DBR nanogratings can provide a promising route for increasing the efficiency of AlGaN-based LEDs, also, to functioning as facet mirror for AlGaN-based laser diodes.

Enhancing the Light-Extraction Efficiency of AlGaN Nanowires Ultraviolet Light-Emitting Diode by using Nitride/Air Distributed Bragg Reflector Nanogratings

KAUST Repository

Alias, Mohd Sharizal

2017-09-11

The performance and efficiency of AlGaN ultraviolet light-emitting diodes have been limited by the extremely low light-extraction efficiency (LEE) due to the intrinsic material properties of AlGaN. Here, to enhance the LEE of the device, we demonstrate an AlGaN nanowires light-emitting diode (NWs-LED) integrated with nitride/air Distributed Bragg Reflector (DBR) nanogratings. Compared to a control device (only mesa), the AlGaN NWs-LED with the nitride/air DBR nanogratings exhibit enhancement in the light output power and external quantum efficiency (EQE) by a factor of ∼1.67. The higher light output power and EQE are attributed mainly to the multiple reflectances laterally for the transverse magnetic (TM)-polarized light and scattering introduced by the nanogratings. To further understand the LEE enhancement, the electrical field distribution, extraction ratio and polar pattern of the AlGaN NWs-LED with and without the nitride/air DBR nanogratings were analyzed using the finite-difference-time-domain method. It was observed that the TM-field emission was confined and scattered upward whereas the polar pattern was intensified for the AlGaN NWs-LED with the nanogratings. Our approach to enhance the LEE via the nitride/air DBR nanogratings can provide a promising route for increasing the efficiency of AlGaN-based LEDs, also, to functioning as facet mirror for AlGaN-based laser diodes.

High-efficiency white OLEDs based on small molecules

Science.gov (United States)

Hatwar, Tukaram K.; Spindler, Jeffrey P.; Ricks, M. L.; Young, Ralph H.; Hamada, Yuuhiko; Saito, N.; Mameno, Kazunobu; Nishikawa, Ryuji; Takahashi, Hisakazu; Rajeswaran, G.

2004-02-01

Eastman Kodak Company and SANYO Electric Co., Ltd. recently demonstrated a 15" full-color, organic light-emitting diode display (OLED) using a high-efficiency white emitter combined with a color-filter array. Although useful for display applications, white emission from organic structures is also under consideration for other applications, such as solid-state lighting, where high efficiency and good color rendition are important. By incorporating adjacent blue and orange emitting layers in a multi-layer structure, highly efficient, stable white emission has been attained. With suitable host and dopant combinations, a luminance yield of 20 cd/A and efficiency of 8 lm/W have been achieved at a drive voltage of less than 8 volts and luminance level of 1000 cd/m2. The estimated external efficiency of this device is 6.3% and a high level of operational stability is observed. To our knowledge, this is the highest performance reported so far for white organic electroluminescent devices. We will review white OLED technology and discuss the fabrication and operating characteristics of these devices.

SolAir. Innovative solar collectors for efficient and cost-effective solar thermal power generation - Final report

Energy Technology Data Exchange (ETDEWEB)

Barbato, M. C.; Haueter, Ph.; Bader, R.; Steinfeld, A.; Pedretti, A.

2008-12-15

This report presents the main results of the project. The project has been started at the end of 2007 and has been successfully finished in December 2008. The present project of ALE AirLight Energy aims at the engineering investigation and design of a novel concept of a solar collector system for efficient and cost-effective solar thermal power generation. The technology exploits an air-inflated reflective structure to concentrate solar radiation. This new arrangement reduces investment costs of the collector field and promises to be economically competitive. A first prototype, built in 2007, has been redesigned and heavily modified during this project. In the new configuration, by using secondary mirrors, the focal area is located close to the main structure and allows the integration of the receiver into the inflated structure. The topics developed in this document are as follows: (i) Design solutions for the concentrated energy receiver suitable for the revised SolAir concentrator concept. (ii) Solar flux simulation via Monte Carlo method. (iii) New version of the ALE AirLight Energy concentrator prototype. (iv) Prototype radiative flux measurements. (author)

Experimental test of a novel multi-surface trough solar concentrator for air heating

International Nuclear Information System (INIS)

Zheng Hongfei; Tao Tao; Ma Ming; Kang Huifang; Su Yuehong

2012-01-01

Highlights: ► We made a prototype novel multi-surface trough solar concentrator for air heating. ► Circular and rectangular types of receiver were chosen for air heating in the test. ► The changes of instantaneous system efficiency with different air flow were obtained. ► The system has the advantage of high collection temperature, which can be over 140 °C. ► The average efficiency can exceed 45% at the outlet temperature of above 60 °C. - Abstract: This study presents the experimental test of a novel multi-surface trough solar concentrator for air heating. Three receivers of different air flow channels are individually combined with the solar concentrator. The air outlet temperature and solar irradiance were recorded for different air flow rates under the real weather condition and used to determine the collection efficiency and time constant of the air heater system. The characteristics of the solar air heater with different airflow channels are compared, and the variation of the daily efficiency with the normalized temperature change is also presented. The testing results indicates that the highest temperature of the air heater with a circular glass receiver can be over 140 °C. When the collection temperature is around 60 °C, the collection efficiency can be over 45%. For the rectangular receivers, the system also has a considerable daily efficiency at a larger air flow rate. The air heater based on the novel trough solar concentrator would be suitable for space heating and drying applications.

Thermal Environment for Classrooms. Central System Approach to Air Conditioning.

Science.gov (United States)

Triechler, Walter W.

This speech compares the air conditioning requirements of high-rise office buildings with those of large centralized school complexes. A description of one particular air conditioning system provides information about the system's arrangement, functions, performance efficiency, and cost effectiveness. (MLF)

Economic and environmental evaluation of compressed-air cars

International Nuclear Information System (INIS)

Creutzig, Felix; Kammen, Daniel M; Papson, Andrew; Schipper, Lee

2009-01-01

Climate change and energy security require a reduction in travel demand, a modal shift, and technological innovation in the transport sector. Through a series of press releases and demonstrations, a car using energy stored in compressed air produced by a compressor has been suggested as an environmentally friendly vehicle of the future. We analyze the thermodynamic efficiency of a compressed-air car powered by a pneumatic engine and consider the merits of compressed air versus chemical storage of potential energy. Even under highly optimistic assumptions the compressed-air car is significantly less efficient than a battery electric vehicle and produces more greenhouse gas emissions than a conventional gas-powered car with a coal intensive power mix. However, a pneumatic-combustion hybrid is technologically feasible, inexpensive and could eventually compete with hybrid electric vehicles.

Approaches to achieve high grain yield and high resource use efficiency in rice

Directory of Open Access Journals (Sweden)

Jianchang YANG

2015-06-01

Full Text Available This article discusses approaches to simultaneously increase grain yield and resource use efficiency in rice. Breeding nitrogen efficient cultivars without sacrificing rice yield potential, improving grain fill in later-flowering inferior spikelets and enhancing harvest index are three important approaches to achieving the dual goal of high grain yield and high resource use efficiency. Deeper root distribution and higher leaf photosynthetic N use efficiency at lower N rates could be used as selection criteria to develop N-efficient cultivars. Enhancing sink activity through increasing sugar-spikelet ratio at the heading time and enhancing the conversion efficiency from sucrose to starch though increasing the ratio of abscisic acid to ethylene in grains during grain fill could effectively improve grain fill in inferior spikelets. Several practices, such as post-anthesis controlled soil drying, an alternate wetting and moderate soil drying regime during the whole growing season, and non-flooded straw mulching cultivation, could substantially increase grain yield and water use efficiency, mainly via enhanced remobilization of stored carbon from vegetative tissues to grains and improved harvest index. Further research is needed to understand synergistic interaction between water and N on crop and soil and the mechanism underlying high resource use efficiency in high-yielding rice.

Efficiency and limitations of the upper airway mucosa as an air conditioner evaluated from the mechanisms of bronchoconstriction in asthmatic subjects.

Science.gov (United States)

Konno, A; Terada, N; Okamoto, Y; Togawa, K

1985-01-01

To elucidate a limit to the efficiency of the upper airway mucosa as an air conditioner, the temperatures of the inspiratory air and mucosa were measured in the cervical trachea. Both of them were affected only minimally by change of atmospheric air temperature during resting nose breathing, but were affected greatly by change of mode of breathing. During hyperventilation through the mouth, when the atmospheric air temperature was 1 degree C, a temperature difference of 9 degrees C was noted between inspiratory air in the cervical trachea and body temperature, together with a mucosal temperature fall by 1.86 +/- 0.61 degree C. Wearing of a mask caused a rise of 3 degrees C in the inspiratory air temperature in the cervical trachea.

Critical study of high efficiency deep grinding

OpenAIRE

Johnstone, lain

2002-01-01

The recent years, the aerospace industry in particular has embraced and actively pursued the development of stronger high performance materials, namely nickel based superalloys and hardwearing steels. This has resulted in a need for a more efficient method of machining, and this need was answered with the advent of High Efficiency Deep Grinding (HEDG). This relatively new process using Cubic Boron Nitride (CBN) electroplated grinding wheels has been investigated through experim...

Improvement of energy efficiency: the use of thermography and air-tightness test in verification of thermal performance of school buildings

Science.gov (United States)

Kauppinen, Timo; Siikanen, Sami

2011-05-01

The improvement of energy efficiency is the key issue after the energy performance of buildings directive came into the force in European Union countries. The city of Kuopio participate a project, in which different tools will be used, generated and tested to improve the energy efficiency of public buildings. In this project there are 2 schools, the other consuming much more heating energy than the other same type of school. In this paper the results of the thermography in normal conditions and under 50 Pa pressure drop will be presented; as well as the results of remote controlled air tightness test of the buildings. Thermography combined with air tightness test showed clearly the reasons of specific consumption differences of heating energy - also in the other hand, the measurements showed the problems in the performance of ventilation system. Thermography, air tightness test and other supporting measurements can be used together to solve energy loss problems - if these measurements will be carried out by proper way.

Continuous fabrication of a MnS/Co nanofibrous air electrode for wide integration of rechargeable zinc-air batteries.

Science.gov (United States)

Wang, Yang; Fu, Jing; Zhang, Yining; Li, Matthew; Hassan, Fathy Mohamed; Li, Guang; Chen, Zhongwei

2017-10-26

Exploring highly efficient bifunctional electrocatalysts toward the oxygen reduction and evolution reactions is essential for the realization of high-performance rechargeable zinc-air batteries. Herein, a novel nanofibrous bifunctional electrocatalyst film, consisting of metallic manganese sulfide and cobalt encapsulated by nitrogen-doped carbon nanofibers (CMS/NCNF), is prepared through a continuous electrospinning method followed by carbonization treatment. The CMS/NCNF bifunctional catalyst shows both comparable ORR and OER performances to those of commercial precious metal-based catalysts. Furthermore, the free-standing CMS/NCNF fibrous thin film is directly used as the air electrode in a solid-state zinc-air battery, which exhibits superior flexibility while retaining stable battery performance at different bending angles. This study provides a versatile design route for the rational design of free-standing bifunctional catalysts for direct use as the air electrode in rechargeable zinc-air batteries.

Combustion phasing for maximum efficiency for conventional and high efficiency engines

International Nuclear Information System (INIS)

Caton, Jerald A.

2014-01-01

Highlights: • Combustion phasing for max efficiency is a function of engine parameters. • Combustion phasing is most affected by heat transfer, compression ratio, burn duration. • Combustion phasing is less affected by speed, load, equivalence ratio and EGR. • Combustion phasing for a high efficiency engine was more advanced. • Exergy destruction during combustion as functions of combustion phasing is reported. - Abstract: The importance of the phasing of the combustion event for internal-combustion engines is well appreciated, but quantitative details are sparse. The objective of the current work was to examine the optimum combustion phasing (based on maximum bmep) as functions of engine design and operating variables. A thermodynamic, engine cycle simulation was used to complete this assessment. As metrics for the combustion phasing, both the crank angle for 50% fuel mass burned (CA 50 ) and the crank angle for peak pressure (CA pp ) are reported as functions of the engine variables. In contrast to common statements in the literature, the optimum CA 50 and CA pp vary depending on the design and operating variables. Optimum, as used in this paper, refers to the combustion timing that provides the maximum bmep and brake thermal efficiency (MBT timing). For this work, the variables with the greatest influence on the optimum CA 50 and CA pp were the heat transfer level, the burn duration and the compression ratio. Other variables such as equivalence ratio, EGR level, engine speed and engine load had a much smaller impact on the optimum CA 50 and CA pp . For the conventional engine, for the conditions examined, the optimum CA 50 varied between about 5 and 11°aTDC, and the optimum CA pp varied between about 9 and 16°aTDC. For a high efficiency engine (high dilution, high compression ratio), the optimum CA 50 was 2.5°aTDC, and the optimum CA pp was 7.8°aTDC. These more advanced values for the optimum CA 50 and CA pp for the high efficiency engine were

Junior High School Pupils' Perceptions of Air

African Journals Online (AJOL)

cce

Abstract. The study examined Junior High School (JHS) pupils' ideas of the concept air. The ... Stavy (1991) reported that students in his physics class had ... Research studies found that even after having been taught the particulate theory and.

Ultrathin high band gap solar cells with improved efficiencies from the world's oldest photovoltaic material.

Science.gov (United States)

Todorov, Teodor K; Singh, Saurabh; Bishop, Douglas M; Gunawan, Oki; Lee, Yun Seog; Gershon, Talia S; Brew, Kevin W; Antunez, Priscilla D; Haight, Richard

2017-09-25

Selenium was used in the first solid state solar cell in 1883 and gave early insights into the photoelectric effect that inspired Einstein's Nobel Prize work; however, the latest efficiency milestone of 5.0% was more than 30 years ago. The recent surge of interest towards high-band gap absorbers for tandem applications led us to reconsider this attractive 1.95 eV material. Here, we show completely redesigned selenium devices with improved back and front interfaces optimized through combinatorial studies and demonstrate record open-circuit voltage (V OC ) of 970 mV and efficiency of 6.5% under 1 Sun. In addition, Se devices are air-stable, non-toxic, and extremely simple to fabricate. The absorber layer is only 100 nm thick, and can be processed at 200 ˚C, allowing temperature compatibility with most bottom substrates or sub-cells. We analyze device limitations and find significant potential for further improvement making selenium an attractive high-band-gap absorber for multi-junction device applications.Wide band gap semiconductors are important for the development of tandem photovoltaics. By introducing buffer layers at the front and rear side of solar cells based on selenium; Todorov et al., reduce interface recombination losses to achieve photoconversion efficiencies of 6.5%.

Span efficiency in hawkmoths.

Science.gov (United States)

Henningsson, Per; Bomphrey, Richard J

2013-07-06

Flight in animals is the result of aerodynamic forces generated as flight muscles drive the wings through air. Aerial performance is therefore limited by the efficiency with which momentum is imparted to the air, a property that can be measured using modern techniques. We measured the induced flow fields around six hawkmoth species flying tethered in a wind tunnel to assess span efficiency, ei, and from these measurements, determined the morphological and kinematic characters that predict efficient flight. The species were selected to represent a range in wingspan from 40 to 110 mm (2.75 times) and in mass from 0.2 to 1.5 g (7.5 times) but they were similar in their overall shape and their ecology. From high spatio-temporal resolution quantitative wake images, we extracted time-resolved downwash distributions behind the hawkmoths, calculating instantaneous values of ei throughout the wingbeat cycle as well as multi-wingbeat averages. Span efficiency correlated positively with normalized lift and negatively with advance ratio. Average span efficiencies for the moths ranged from 0.31 to 0.60 showing that the standard generic value of 0.83 used in previous studies of animal flight is not a suitable approximation of aerodynamic performance in insects.

Highly efficient red electrophosphorescent devices at high current densities

International Nuclear Information System (INIS)

Wu Youzhi; Zhu Wenqing; Zheng Xinyou; Sun, Runguang; Jiang Xueyin; Zhang Zhilin; Xu Shaohong

2007-01-01

Efficiency decrease at high current densities in red electrophosphorescent devices is drastically restrained compared with that from conventional electrophosphorescent devices by using bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (BAlq) as a hole and exciton blocker. Ir complex, bis(2-(2'-benzo[4,5-α]thienyl) pyridinato-N,C 3' ) iridium (acetyl-acetonate) is used as an emitter, maximum external quantum efficiency (QE) of 7.0% and luminance of 10000cd/m 2 are obtained. The QE is still as high as 4.1% at higher current density J=100mA/cm 2 . CIE-1931 co-ordinates are 0.672, 0.321. A carrier trapping mechanism is revealed to dominate in the process of electroluminescence

Electricity generation and nutrients removal from high-strength liquid manure by air-cathode microbial fuel cells.

Science.gov (United States)

Lin, Hongjian; Wu, Xiao; Nelson, Chad; Miller, Curtis; Zhu, Jun

2016-01-01

Air-cathode microbial fuel cells (MFCs) are widely tested to recover electrical energy from waste streams containing organic matter. When high-strength wastewater, such as liquid animal manure, is used as a medium, inhibition on anode and cathode catalysts potentially impairs the effectiveness of MFC performance in power generation and pollutant removal. This study evaluated possible inhibitive effects of liquid swine manure components on MFC power generation, improved liquid manure-fed MFCs performance by pretreatment (dilution and selective adsorption), and modeled the kinetics of organic matter and nutrients removal kinetics. Parameters monitored included pH, conductivity, chemical oxygen demand (COD), volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), nitrite, nitrate, and phosphate concentrations. The removals of VFA and TAN were efficient, indicated by the short half-life times of 4.99 and 7.84 d, respectively. The mechanism for phosphate decrease was principally the salt precipitation on cathode, but the removal was incomplete after 42-d operation. MFC with an external resistor of 2.2 kΩ and fed with swine wastewater generated relatively small power (28.2 μW), energy efficiency (0.37%) and Coulombic efficiency (1.5%). Dilution of swine wastewater dramatically improved the power generation as the inhibitory effect was decreased. Zeolite and granular activated carbon were effective in the selective adsorption of ammonia or organic matter in swine wastewater, and so substantially improved the power generation, energy efficiency, and Coulombic efficiency. A smaller external resistor in the circuit was also observed to promote the organic matter degradation and thus to shorten the treatment time. Overall, air-cathode MFCs are promising for generating electrical power from livestock wastewater and meanwhile reducing the level of organic matter and nutrients.

Global thermal analysis of air-air cooled motor based on thermal network

Science.gov (United States)

Hu, Tian; Leng, Xue; Shen, Li; Liu, Haidong

2018-02-01

The air-air cooled motors with high efficiency, large starting torque, strong overload capacity, low noise, small vibration and other characteristics, are widely used in different department of national industry, but its cooling structure is complex, it requires the motor thermal management technology should be high. The thermal network method is a common method to calculate the temperature field of the motor, it has the advantages of small computation time and short time consuming, it can save a lot of time in the initial design phase of the motor. The domain analysis of air-air cooled motor and its cooler was based on thermal network method, the combined thermal network model was based, the main components of motor internal and external cooler temperature were calculated and analyzed, and the temperature rise test results were compared to verify the correctness of the combined thermal network model, the calculation method can satisfy the need of engineering design, and provide a reference for the initial and optimum design of the motor.

Air and gas cleaning technology for nuclear applications

International Nuclear Information System (INIS)

First, M.W.

1986-01-01

All large-scale uses of radioactive materials require rigid control of off-gases and generated aerosols. Nuclear air and gas cleaning technology has answered the need from the days of the Manhattan Project to the present with a variety of devices. The one with the longest and most noteworthy service is the HEPA (high efficiency particulate air) filter that originally was referred to as an absolute filter in recognition of its extraordinary particle retention characteristics. Activated-charcoal adsorbers have been employed worldwide for retention of volatile radioiodine in molecular and combined forms and, less frequently, for retention of radioactive noble gases. HEPA filters and activated -charcoal adsorbers are often used with auxiliary devices that serve to extend their effective service life or significantly improve collection efficiency under unfavorable operating conditions. Use of both air cleaning devices and their auxiliaries figure prominently in atomic energy, disposal of high- and low-level nuclear wastes, and in the production of fissile materials. The peaceful uses of nuclear energy would be impossible without these, or equivalent, air- and gas-cleaning devices

Large high altitude air shower observatory (LHAASO) project

International Nuclear Information System (INIS)

He Huihai

2010-01-01

The Large High Altitude Air Shower Observatory (LHAASO) project focuses mainly on the study of 40 GeV-1 PeV gamma ray astronomy and 10 TeV-1 EeV cosmic ray physics. It consists of a 1 km 2 extensive air shower array with 40 000 m 2 muon detectors, 90,000m 2 water Cerenkov detector array, 5 000 m 2 shower core detector array and an air Cerenkov/fluorescence telescope array. Prototype detectors are designed with some of them already in operation. A prototype array of 1% size of LHAASO will be built at the Yangbajing Cosmic Ray Observatory and used to coincidently measure cosmic rays with the ARGO-YBJ experiment. (authors)

High Efficiency, Low Emission Refrigeration System

Energy Technology Data Exchange (ETDEWEB)

Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

2016-08-01

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Methods for reducing refrigerant leakage and energy consumption are available, but underutilized. Further work needs to be done to reduce costs of advanced system designs to improve market utilization. In addition, refrigeration system retrofits that result in reduced energy consumption are needed since the majority of applications address retrofits rather than new stores. The retrofit market is also of most concern since it involves large-volume refrigerant systems with high leak rates. Finally, alternative refrigerants for new and retrofit applications are needed to reduce emissions and reduce the impact on the environment. The objective of this Collaborative Research and Development Agreement (CRADA) between the Oak Ridge National Laboratory and Hill Phoenix is to develop a supermarket refrigeration system that reduces greenhouse gas emissions and has 25 to 30 percent lower energy consumption than existing systems. The outcomes of this project will include the design of a low emission, high efficiency commercial refrigeration system suitable for use in current U.S. supermarkets. In addition, a prototype low emission, high efficiency supermarket refrigeration system will be produced for

Air filtration media from electrospun waste high-impact polystyrene fiber membrane

Science.gov (United States)

Zulfi, Akmal; Miftahul Munir, Muhammad; Hapidin, Dian Ahmad; Rajak, Abdul; Edikresnha, Dhewa; Iskandar, Ferry; Khairurrijal, Khairurrijal

2018-03-01

Nanofiber membranes were synthesized from waste high-impact polystyrene (HIPS) using electrospinning method and then applied as air filtration media. The waste HIPS precursor solution with the concentration of 20 wt.% was prepared by dissolving waste HIPS into the mixture of d-limonene and DMF solvents. Beaded or fine nanofibers could be achieved by adjusting the ratio of solvents mixture (d-limonene and DMF). Using the ratios of solvents (d-limonene: DMF) of 3:1, 1:1, and 1:3, it was obtained beaded HIPS nanofibers with the average diameter of 272 nm, beaded HIPS nanofibers with the average diameter of 937, and fine HIPS nanofibers with the average diameter of 621 nm, respectively. From the FTIR spectral analysis, it was found that the FTIR peaks of the HIPS nanofiber membranes are the same as those of the cleaned waste HIPS and there are no FTIR peaks of DMF and d-limonene solvents. These findings implied that the electrospinning process allows the recycling of waste HIPS into HIPS nanofibers without any trapped solvent phases or apparent degradation of the original material. From the contact angle measurement, it was confirmed that the HIPS nanofiber membranes are hydrophobic and the presence of the beads in the HIPS nanofiber membranes varies their contact angles. From the air-filtration test, it was shown that the fiber morphology (beaded or fine nanofibers) considerably affects the filtration performance of the membranes. The presence of beads increased the distance between the fibers so that the pressure drop decreased. Moreover, the basis weight of the membrane greatly affected the filtration efficiency. The HIPS nanofiber membrane with the basis weight of 12.22 g m‑2 had the efficiency greater than 99.999%, which was equivalent to that of the HEPA filter.

Efficient air pollution regulation of coal-fired power in China

Science.gov (United States)

Feng, Therese

This dissertation evaluates monetary external costs of electricity generation in the People's Republic of China and implications for efficient pollution control policy. It presents an integrated assessment of environmental damages of air emissions of a representative new coal-fired plant in urban areas of north and south China. The simulation evaluates the nature and magnitude of damages in China, transboundary effects in Japan and Korea, and global greenhouse gas warming impacts. The valuation is used to identify efficient abatement policy for Chinese plants over time; evaluate benefits of differentiated policies; and consider the importance of dynamic policy. Potential annual damages of operating a 600-MW power plant without controls in China today would be 43-45 million (U.S. 1995). Annual local damages of 37-40 million far exceed transboundary or greenhouse gas damages (1.4 million and $4.6 million respectively). The largest component of damages is the risk of human mortality and chronic morbidity from long-term exposure to fine particles. Efficient pollution control minimizes the sum of abatement costs and residual unabated damages. Because monetary damages reflect sufferers' willingness to pay to avoid environmental risks, the choice of efficient controls is fundamentally tied to societal values and preferences. The optimal path for Chinese abatement moves from modest dispersion measures at present to combined dispersion and emission controls approaching those of current-day United States, by 2050. The inclusion of transboundary and greenhouse damages does not substantively alter local policies. Welfare benefits are gained by differentiating abatement policy by pollutant, meteorological parameters, and by population density. An analysis of optimal one-time investment in abatement for a plant in a growing economy suggests that some investment is optimal at all incomes but no single level of abatement is suitable for all economies. Forward-looking policy

Field Measurements of Heating Efficiency of Electric Forced-Air Furnaces in Six Manufactured Homes.

Energy Technology Data Exchange (ETDEWEB)

Davis, Bob; Palmiter, Larry S.; Siegel, Jeff

1994-07-26

This report presents the results of field measurements of heating efficiency for six manufactured homes in the Pacific Northwest heated with electric forced-air systems. This is the first in a series of regional and national efforts to measure in detail the heating efficiency of manufactured homes. Only six homes were included in this study because of budgetary constraints; therefore this is not a representative sample. These investigations do provide some useful information on the heating efficiency of these homes. Useful comparisons can be drawn between these study homes and site-built heating efficiencies measured with a similar protocol. The protocol used to test these homes is very similar to another Ecotope protocol used in the study conducted in 1992 and 1993 for the Bonneville Power Administration to test the heating efficiency of 24 homes. This protocol combined real-time power measurements of furnace energy usage with energy usage during co-heat periods. Accessory data such as house and duct tightness measurements and tracer gas measurements were used to describe these homes and their heating system efficiency. Ensuring that manufactured housing is constructed in an energy and resource efficient manner is of increasing concern to manufactured home builders and consumers. No comparable work has been done to measure the heating system efficiency of MCS manufactured homes, although some co-heat tests have been performed on manufactured homes heated with natural gas to validate HUD thermal standards. It is expected that later in 1994 more research of this kind will be conducted, and perhaps a less costly and less time-consuming method for testing efficiencies will be develops.

Simple Motor Control Concept Results High Efficiency at High Velocities

Science.gov (United States)

Starin, Scott; Engel, Chris

2013-09-01

The need for high velocity motors in space applications for reaction wheels and detectors has stressed the limits of Brushless Permanent Magnet Motors (BPMM). Due to inherent hysteresis core losses, conventional BPMMs try to balance the need for torque verses hysteresis losses. Cong-less motors have significantly less hysteresis losses but suffer from lower efficiencies. Additionally, the inherent low inductance in cog-less motors result in high ripple currents or high switching frequencies, which lowers overall efficiency and increases performance demands on the control electronics.However, using a somewhat forgotten but fully qualified technology of Isotropic Magnet Motors (IMM), extremely high velocities may be achieved at low power input using conventional drive electronics. This paper will discuss the trade study efforts and empirical test data on a 34,000 RPM IMM.

High efficiency nebulization for helium inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Jorabchi, Kaveh; McCormick, Ryan; Levine, Jonathan A.; Liu Huiying; Nam, S.-H.; Montaser, Akbar

2006-01-01

A pneumatically-driven, high efficiency nebulizer is explored for helium inductively coupled plasma mass spectrometry. The aerosol characteristics and analyte transport efficiencies of the high efficiency nebulizer for nebulization with helium are measured and compared to the results obtained with argon. Analytical performance indices of the helium inductively coupled plasma mass spectrometry are evaluated in terms of detection limits and precision. The helium inductively coupled plasma mass spectrometry detection limits obtained with the high efficiency nebulizer at 200 μL/min are higher than those achieved with the ultrasonic nebulizer consuming 2 mL/min solution, however, precision is generally better with high efficiency nebulizer (1-4% vs. 3-8% with ultrasonic nebulizer). Detection limits with the high efficiency nebulizer at 200 μL/min solution uptake rate approach those using ultrasonic nebulizer upon efficient desolvation with a heated spray chamber followed by a Peltier-cooled multipass condenser

Evaluation of food drying with air dehumidification system: a short review

Science.gov (United States)

Djaeni, M.; Utari, F. D.; Sasongko, S. B.; Kumoro, A. C.

2018-01-01

Energy efficient drying for food and agriculture products resulting high quality products has been an important issue. Currently, about 50% of total energy for postharvest treatment was used for drying. This paper presents the evaluation of new approach namely air dehumidification system with zeolite for food drying. Zeolite is a material having affinity to water in which reduced the moisture in air. With low moisture content and relative humidity, the air can improve driving force for drying even at low temperature. Thus, the energy efficiency can be potentially enhanced and the product quality can be well retained. For proving the hypothesis, the paddy and onion have been dried using dehumidified air. As performance indicators, the drying time, product quality, and heat efficiency were evaluated. Results indicated that the drying with zeolite improved the performances significantly. At operating temperature ranging 50 - 60°C, the efficiency of drying system can reach 75% with reasonable product quality.

Air pollution control at a DOE facility

International Nuclear Information System (INIS)

Curn, B.L.

1995-11-01

The Department of Energy (DOE) plutonium production program Produced some of the greatest scientific and engineering accomplishments of all time. It is remarkable to consider the accomplishments of the Manhattan Project. The Reactor on the Hanford Site, the first production reactor in the world, began operation only 13 months after the start of construction. The DOE nuclear production program was also instrumental in pioneering other fields such as health physics an radiation monitoring. The safety record of these installations is remarkable considering that virtually every significant accomplishment was on the technological threshold of the time. One other area that the DOE Facilities pioneered was the control of radioactive particles and gases emitted to the atmosphere. The high efficiency particulate air filter (HEPA) was a development that provided high collection efficiencies of particulates to protect workers and the public. The halogen and noble gases also were of particular concern. Radioactive iodine is captured by adsorption on activated carbon or synthetic zeolites. Besides controlling radioncuclide air pollution, DOE facilities are concerned with other criteria pollutants and hazardous air pollutant emissions. The Hanford Site encompasses all those air pollution challenges

Analytic Methods for Tactical Air Warfare. Air Campaign and High-Energy Laser Propagation Analyses

National Research Council Canada - National Science Library

Lee, David

2004-01-01

.... The report describes a probabilistic model of campaigns for air superiority between two opponents, an analysis of force concentration in deterministic Lanchester campaigns, and an analysis of high...

High Efficiency Power Converter for Low Voltage High Power Applications

DEFF Research Database (Denmark)

Nymand, Morten

The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

An efficient dye-sensitized BiOCl photocatalyst for air and water purification under visible light irradiation.

Science.gov (United States)

Li, Guisheng; Jiang, Bo; Xiao, Shuning; Lian, Zichao; Zhang, Dieqing; Yu, Jimmy C; Li, Hexing

2014-08-01

A photosensitized BiOCl catalyst was found to be effective for photocatalytic water purification and air remediation under visible light irradiation (λ > 420 nm). Prepared by a solvothermal method, the BiOCl crystals possessed a 3D hierarchical spherical structure with the highly active facets exposed. When sensitized by Rhodamine B (RhB), the photocatalyst system was more active than N-doped TiO2 for breaking down 4-chlorophenol (4-CP, 200 ppm) and nitric monoxide (NO, 500 ppb). The high activity could be attributed to the hierarchical structure (supplying feasible reaction tunnels for adsorption and transition of reactants or products) and the efficient exposure of the {001} facets. The former provides an enriched oxygen atom density that promotes adsorption of cationic dye RhB, and creates an oxygen vacancy state. The HO˙ and ˙O2(-) radicals produced from the injected electrons from the excited dye molecule (RhB*) into the conduction band of BiOCl were responsible for the excellent photocatalytic performance of the RhB-BiOCl system.

High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

DEFF Research Database (Denmark)

Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance a......This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

Hypothetical air ingress scenarios in advanced modular high temperature gas cooled reactors

International Nuclear Information System (INIS)

Kroeger, P.G.

1988-01-01

Considering an extremely hypothetical scenario of complete cross duct failure and unlimited air supply into the reactor vessel of a modular high temperature gas cooled ractor, it is found that the potential air inflow remains limited due to the high friction pressure drop through the active core. All incoming air will be oxidized to CO and some local external burning would be temporarily possible in such a scenario. The accident would have to continue with unlimited air supply for hundreds of hours before the core structural integrity would be jeopardized

High-efficiency silicon solar cells for low-illumination applications

OpenAIRE

Glunz, S.W.; Dicker, J.; Esterle, M.; Hermle, M.; Isenberg, J.; Kamerewerd, F.; Knobloch, J.; Kray, D.; Leimenstoll, A.; Lutz, F.; Oßwald, D.; Preu, R.; Rein, S.; Schäffer, E.; Schetter, C.

2002-01-01

At Fraunhofer ISE the fabrication of high-efficiency solar cells was extended from a laboratory scale to a small pilot-line production. Primarily, the fabricated cells are used in small high-efficiency modules integrated in prototypes of solar-powered portable electronic devices such as cellular phones, handheld computers etc. Compared to other applications of high-efficiency cells such as solar cars and planes, the illumination densities found in these mainly indoor applications are signific...

Metal-air batteries with high energy density: Li-air versus Zn-air

Energy Technology Data Exchange (ETDEWEB)

Lee, Jang-Soo; Sun, Tai Kim; Cao, Ruiguo; Choi, Nam-Soon; Lee, Kyu Tae; Cho, Jaephil [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of); Liu, Meilin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

2011-01-01

In the past decade, there have been exciting developments in the field of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion batteries having topatactic chemistry is not sufficient to meet the demands of new markets in such areas as electric vehicles. Therefore, new electrochemical systems with higher energy densities are being sought, and metal-air batteries with conversion chemistry are considered a promising candidate. More recently, promising electrochemical performance has driven much research interest in Li-air and Zn-air batteries. This review provides an overview of the fundamentals and recent progress in the area of Li-air and Zn-air batteries, with the aim of providing a better understanding of the new electrochemical systems. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

High Efficiency Colloidal Quantum Dot Phosphors

Energy Technology Data Exchange (ETDEWEB)

Kahen, Keith

2013-12-31

The project showed that non-Cd containing, InP-based nanocrystals (semiconductor materials with dimensions of ~6 nm) have high potential for enabling next-generation, nanocrystal-based, on chip phosphors for solid state lighting. Typical nanocrystals fall short of the requirements for on chip phosphors due to their loss of quantum efficiency under the operating conditions of LEDs, such as, high temperature (up to 150 °C) and high optical flux (up to 200 W/cm2). The InP-based nanocrystals invented during this project maintain high quantum efficiency (>80%) in polymer-based films under these operating conditions for emission wavelengths ranging from ~530 to 620 nm. These nanocrystals also show other desirable attributes, such as, lack of blinking (a common problem with nanocrystals which limits their performance) and no increase in the emission spectral width from room to 150 °C (emitters with narrower spectral widths enable higher efficiency LEDs). Prior to these nanocrystals, no nanocrystal system (regardless of nanocrystal type) showed this collection of properties; in fact, other nanocrystal systems are typically limited to showing only one desirable trait (such as high temperature stability) but being deficient in other properties (such as high flux stability). The project showed that one can reproducibly obtain these properties by generating a novel compositional structure inside of the nanomaterials; in addition, the project formulated an initial theoretical framework linking the compositional structure to the list of high performance optical properties. Over the course of the project, the synthetic methodology for producing the novel composition was evolved to enable the synthesis of these nanomaterials at a cost approximately equal to that required for forming typical conventional nanocrystals. Given the above results, the last major remaining step prior to scale up of the nanomaterials is to limit the oxidation of these materials during the tens of

Efficiency of an air-cooled thermodynamic cycle

International Nuclear Information System (INIS)

Bezborodov, Yu.A.; Bubnov, V.P.; Nesterenko, V.B.

1979-01-01

The application of air, nitrogen, helium and the chemically reacting N 2 O 4 reversible 2NO 2 reversible 2NO + O 2 system as working agents and coolants for a low capacity nuclear power plant is investigated. The above system due to its physico-chemical and thermo-physical properties allows both a gaseous cycle and a cycle with condensation. The analysis has shown that a thermodynamic air-cooled cycle with the dissociating nitrogen tetroxide in the temperature range from 500 to 600 deg C has an advantage over cycles with air and nitrogen. To identify the chemical reaction kinetics in the thermodynamic processes, thermodynamic calculations of the gas-liquid cycle with N 2 O 4 both with simple and intermediate heat regeneration at different pressures over hot side were performed. At gas pressures lower than 12 - 15 atm, the cycle with a simple regeneration is more effective, and at pressure increase, the cycle with an intermediate regeneration is preferable

Air filters for use at nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Linder, P [Aktiebolaget Atomenergi, Studsvik, Nykoeping (Sweden)

1970-12-01

The ventilation system of a nuclear facility plays a vital role in ensuring that the air in working areas and the environment remains free from radioactive contamination. An earlier IAEA publication, Techniques for Controlling Air Pollution from the Operation of Nuclear Facilities, Safety Series No. 17, deals with the design and operation of ventilation systems at nuclear facilities. These systems are usually provided with air-cleaning devices which remove the contaminants from the air. This publication is intended as a guide to those who are concerned with the design of air-filtering systems and with the testing, operation and maintenance of air-filter installations at nuclear facilities. Emphasis is mainly placed on so-called high-efficiency particulate air filters (HEPA filters) and on providing general information on them. Besides describing the usual filter types, their dimensions and construction materials, the guidebook attempts to explain their properties and behaviour under different operating conditions. It also gives advice on testing and handling the filters so that effective and safe performance is ensured. The guidebook should serve as an introduction to the use of high efficiency particulate air filters in countries where work with radioactive materials has only recently commenced. The list of references at the end of the book indicates sources of more advanced information for those who already have comprehensive experience in this field. It is assumed here that the filters are obtained from a manufacturer, and the guidebook thus contains no information on the design and development of the filter itself, nor does it deal with the cleaning of the intake air to a plant, with gas sorption or protective respiratory equipment.

Air filters for use at nuclear facilities

International Nuclear Information System (INIS)

Linder, P.

1970-01-01

The ventilation system of a nuclear facility plays a vital role in ensuring that the air in working areas and the environment remains free from radioactive contamination. An earlier IAEA publication, Techniques for Controlling Air Pollution from the Operation of Nuclear Facilities, Safety Series No. 17, deals with the design and operation of ventilation systems at nuclear facilities. These systems are usually provided with air-cleaning devices which remove the contaminants from the air. This publication is intended as a guide to those who are concerned with the design of air-filtering systems and with the testing, operation and maintenance of air-filter installations at nuclear facilities. Emphasis is mainly placed on so-called high-efficiency particulate air filters (HEPA filters) and on providing general information on them. Besides describing the usual filter types, their dimensions and construction materials, the guidebook attempts to explain their properties and behaviour under different operating conditions. It also gives advice on testing and handling the filters so that effective and safe performance is ensured. The guidebook should serve as an introduction to the use of high efficiency particulate air filters in countries where work with radioactive materials has only recently commenced. The list of references at the end of the book indicates sources of more advanced information for those who already have comprehensive experience in this field. It is assumed here that the filters are obtained from a manufacturer, and the guidebook thus contains no information on the design and development of the filter itself, nor does it deal with the cleaning of the intake air to a plant, with gas sorption or protective respiratory equipment

High-energy air shock study in steel and grout pipes

International Nuclear Information System (INIS)

Glenn, H.D.; Kratz, H.R.; Keough, D.D.; Duganne, D.A.; Ruffner, D.J.; Swift, R.P.; Baum, D.

1979-01-01

Voitenko compressors are used to generate 43 mm/μs air shocks in both a steel and a grout outlet pipe containing ambient atmospheric air. Fiber-optic ports provide diaphragm burst times, time-of-arrival (TOA) data, and velocities for the shock front along the 20-mm-ID exit pipes. Pressure profiles are obtained at higher enthalpy shock propagation than ever before and at many locations along the exit pipes. Numerous other electronic sensors and postshot observations are described, as well as experimental results. The primary objectives of the experiments are as follows: (1) provide a data base for normalization/improvement of existing finite-difference codes that describe high-energy air shocks and gas propagation; (2) obtain quantitative results on the relative attenuation effects of two very different wall materials for high-energy air shocks and gas flows. The extensive experimental results satisfy both objectives

Air leakage control in chief tunnel of uranium mines using air screen

International Nuclear Information System (INIS)

Xiao Gengsheng

1987-01-01

In this paper the results of air leakage control are described using air screen in the chief tunnels of some uranium mines. The air leakage decreases by 79-91% after using air screen. On the basis of mathematical treatment, the formulas for calculating the air resistance efficiency of air screen are presented

Highly efficient fully transparent inverted OLEDs

Science.gov (United States)

Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

2007-09-01

One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

High efficiency lithium-thionyl chloride cell

Science.gov (United States)

Doddapaneni, N.

1982-08-01

The polarization characteristics and the specific cathode capacity of Teflon bonded carbon electrodes in the Li/SOCl2 system have been evaluated. Doping of electrocatalysts such as cobalt and iron phthalocyanine complexes improved both cell voltage and cell rate capability. High efficiency Li/SOCl2 cells were thus achieved with catalyzed cathodes. The electrochemical reduction of SOCl2 seems to undergo modification at catalyzed cathode. For example, the reduction of SOCl2 at FePc catalyzed cathode involves 2-1/2 e-/mole of SOCl2. Furthermore, the reduction mechanism is simplified and unwanted chemical species are eliminated by the catalyst. Thus a potentially safer high efficiency Li/SOCl2 can be anticipated.

Experimental analysis of humidification process by air passing through seawater

International Nuclear Information System (INIS)

El-Agouz, S.A.; Abugderah, M.

2008-01-01

An experimental investigation of humidification process by air passing through seawater is presented. The main objective of this work was to determine the humid air behaviour through single-stage of heating-humidifying processes. This experimental work studied the influence of the operating conditions such as the water temperature, the headwater difference, the air velocity and the inlet air temperature to evaporator chamber on the vapour content difference and humidification efficiency. Two cases of different inlet conditions of ambient and heated air cases are studied. The experimental results show that, the vapour content difference and the humidification efficiency of the system is strongly affected by the saline water temperature in the evaporator chamber, headwater difference and the air velocity. The inlet air temperature to evaporator chamber variation was found to have a small affect on the vapour content difference. The obtained maximum vapour content difference of the air was about 222 gr w /kg a at 75 deg. C for water and air. The obtained vapour content is high compared to that obtained in literature for single-stage and very similar for multi-stage

Development of High-Efficiency Low-Lift Vapor Compression System - Final Report

Energy Technology Data Exchange (ETDEWEB)

Katipamula, Srinivas; Armstrong, Peter; Wang, Weimin; Fernandez, Nicholas; Cho, Heejin; Goetzler, W.; Burgos, J.; Radhakrishnan, R.; Ahlfeldt, C.

2010-03-31

PNNL, with cofunding from the Bonneville Power Administration (BPA) and Building Technologies Program, conducted a research and development activity targeted at addressing the energy efficiency goals targeted in the BPA roadmap. PNNL investigated an integrated heating, ventilation and air conditioning (HVAC) system option referred to as the low-lift cooling system that potentially offers an increase in HVAC energy performance relative to ASHRAE Standard 90.1-2004.

The propagation of high power CW scanning electron beam in air

International Nuclear Information System (INIS)

Korenev, Sergey; Korenev, Ivan

2002-01-01

The question of propagation of high power electron beam in air presents the scientific and applied interests. The high power (80 kW) CW electron accelerator 'Rhodotron' with kinetic energy of electrons 5 and 10 MeV was used in the experiments. The experimental results for propagation of scanning electron beams in air are presented and discussed

Improving the Efficiency of a High Speed Catamaran Through the Replacement of the Propulsion System

Directory of Open Access Journals (Sweden)

German de Melo Rodriguez

2015-12-01

Full Text Available The high speed vessels are primarily designed for short distances services as public transport of passengers and vehicles. The range of high speed, according to the Code of high-speed vessels begins at 20 knots, which depends on the cruise speed you desire for your vessel; you will have to use the most appropriate type of propellant. In general, in the past 20 years, they have been building high-speed vessels with speeds above 33 knots, which meant installing water jet propellants coupled to powerful engines and therefore of high consumption of fuel, increasing operating costs and causing increased air pollution. Although the prices of fuel have been reduced to half, due to the sharp fall in oil prices, the consumption of fuel and the air pollution remains high at these speeds and powers used, in addition to that the reduction of the time spent on each trip is not excessive, mainly in short routes that are less than an hour . This article is about adapting a ship of high-speed service, with a maximum speed in tests of 34 knots and to reduce its operating costs (fuel, maintenance, etc. and make it economically viable; before the transformation, this vessel was operating with a service speed of 22 knots, and with a consumption per mile of 135 litters of MGO. The transformation process has consisted by: – Replacement of the two original water jet with four shaft lines with fix pitch propeller. – Replacement of the two original main engines (2 x 6500 kW = 13000 kW by four engines (4 x 1380kW = 5.520 kW. – Changing the underwater hull shape to fit the new propellers and maximize its efficiency. – Relocation of auxiliary engines, to achieve the most efficient trim. – Installation of two lateral propellers to improve maneuverability and shorten the total time of journey. After the reform and the return to service of the vessel with a service speed of over 22 knots, it has been verified that the consumption per mile is of 45 litters MGO

A novel complex air supply model for indoor air quality control via the occupant micro-environment demand ventilation

International Nuclear Information System (INIS)

Yang, Jie; Zhou, Bo; Jin, Maozhu; Wang, Jun; Xiong, Feng

2016-01-01

Protection of indoor air quality and human health can be achieved via ventilation, which has becomes one of the most important tasks for sustainable buildings. This approach also requires highly efficient and energy saving methods for modern building ventilations consisting of a set of parameters of the complex indoor system. Therefore, the advancement in understanding the characteristics of various ventilation methods is highly necessary. This study presents one novel air supply model for the complex occupant micro-environment demand control ventilations, to analyze the efficiency of various ventilation types. This model is established primarily according to the momentum and mass conservations, and goal of occupant micro-environment demand, which is a complex system with the characteristics of diversity and dynamic variation. As for different occupant densities, characteristics of outdoor air supply for controlling gaseous pollutant and three basic features of outdoor airflow supply reaching occupant micro-environment were obtained. This research shows that for various types of occupant density and storey height, the rising and descending rates of the demand outdoor airflow in mixing ventilation are higher than those under displacement ventilation conditions. In addition, since the structure is better designed and sewage flow is more efficient, the mixing ventilation also requires a much higher peak demand outdoor airflow than its counterpart. The increase of storey height will lead to a decline of pollutants in the breathing zone and the demand outdoor airflow. Fluctuations of air flow diffusion caused by the change of occupant density in architectural space, will lead to variations of outdoor airflow reaching occupant micro-environment. Accordingly, it would lead to the different peak values of demand outdoor airflow, and the difference becomes even significant if the occupant density increases. The variations of the air supply and fraction of air reaching the

Numerically efficient simulation of multi-vaporator air conditioners in highly dynamic boundary conditions; Numerisch effiziente Simulation von Mehrverdampfer-Klimaanlagen unter hochdynamischen Randbedingungen

Energy Technology Data Exchange (ETDEWEB)

Schulze, Christian; Kaiser, Christian [TLK-Thermo GmbH, Braunschweig (Germany); Tegethoff, Wilhelm; Koehler, Juergen [TU Braunschweig (Germany). Inst. fuer Thermodynamik

2011-07-01

In the development of physically based models for dynamic simulations of cycle processes, a good equilibrium must be chosen between the degree of detailing and the speed of calculation. Dynamic modelling of mult-evaporator air conditioners is a special challenge as the interaction of several heat transfer fluides at one pressure level may result in numerically challenging effects like reflux. The contribution goes into the simulation of the heat transfer fluids in such systems in highly dynamic boundary conditions, e.g. after shutoff of the compressor. There are different modelling methods, e.g. finite volume, moving boundary, or finite element analysis. The methods are presented and evaluated. For the 1-D finite volume method, various established simplification strategies are presented that may enhance numerical efficiency. It is also shown that the equation system will not always be solvable with these strategies, and an approach to ensure solvability is presented. The new approach is illustrated by the example of a multi-evaporator bus air conditioner. [German] Bei der Erstellung von physikalisch basierten Modellen fuer die dynamische Simulation von Kreisprozessen muss ein gutes Gleichgewicht zwischen Detaillierungsgrad und Rechengeschwindigkeit gewaehlt werden: Das Modell muss die Realitaet hinreichend genau abbilden, im Gegenzug jedoch auch innerhalb eines angemessenen Zeitraums Ergebnisse liefern sowie in allen Betriebszustaenden loesbar sein. Die dynamische Modellierung von Mehrverdampfer-Klimaanlagen stellt im Vergleich zu einfachen Kreisprozessen eine besondere Herausforderung dar, da in diesen Systemen die Interaktion mehrerer Waermeuebertrager auf einem Druckniveau zu numerisch herausfordernden Effekten wie z. B. Rueckstroemung fuehren kann. Dieser Beitrag beschaeftigt sich mit der Simulation der Waermeuebertrager in diesen Systemen unter hochdynamischen Randbedingungen wie z. B. einer Abschaltung des Verdichters. Zur Modellierung der Waermeuebertrager

Search and Rescue in the High North: An Air Force Mission?

Science.gov (United States)

2013-12-01

at the strange new things in the land of the midnight sun. What wouldn’t surprise him are the things that never change: six months of darkness ...8-98) Prescribed by ANSI Std Z39-18 November–December 2013 Air & Space Power Journal | 5 Conway Search and Rescue in the High North Feature tourism ...official sanction of the Department of Defense, Air Force, Air Education and Training Command, Air University, or other agencies or departments of

Measure Guideline. High Efficiency Natural Gas Furnaces

Energy Technology Data Exchange (ETDEWEB)

Brand, L. [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States); Rose, W. [Partnership for Advanced Residential Retrofit (PARR), Des Plaines, IL (United States)

2012-10-01

This measure guideline covers installation of high-efficiency gas furnaces, including: when to install a high-efficiency gas furnace as a retrofit measure; how to identify and address risks; and the steps to be used in the selection and installation process. The guideline is written for Building America practitioners and HVAC contractors and installers. It includes a compilation of information provided by manufacturers, researchers, and the Department of Energy as well as recent research results from the Partnership for Advanced Residential Retrofit (PARR) Building America team.

An improved high-performance lithium-air battery.

Science.gov (United States)

Jung, Hun-Gi; Hassoun, Jusef; Park, Jin-Bum; Sun, Yang-Kook; Scrosati, Bruno

2012-06-10

Although dominating the consumer electronics markets as the power source of choice for popular portable devices, the common lithium battery is not yet suited for use in sustainable electrified road transport. The development of advanced, higher-energy lithium batteries is essential in the rapid establishment of the electric car market. Owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role. However, the performance of such batteries has been limited to only a few charge-discharge cycles with low rate capability. Here, by choosing a suitable stable electrolyte and appropriate cell design, we demonstrate a lithium-air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh g(carbon)(-1) and 3 A g(carbon)(-1), respectively. For this battery we estimate an energy density value that is much higher than those offered by the currently available lithium-ion battery technology.

Highly Efficient Estimators of Multivariate Location with High Breakdown Point

NARCIS (Netherlands)

Lopuhaa, H.P.

1991-01-01

We propose an affine equivariant estimator of multivariate location that combines a high breakdown point and a bounded influence function with high asymptotic efficiency. This proposal is basically a location $M$-estimator based on the observations obtained after scaling with an affine equivariant

Air ionization as a control technology for off-gas emissions of volatile organic compounds.

Science.gov (United States)

Kim, Ki-Hyun; Szulejko, Jan E; Kumar, Pawan; Kwon, Eilhann E; Adelodun, Adedeji A; Reddy, Police Anil Kumar

2017-06-01

High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO 2 and H 2 O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O 3 ). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O 3 , NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management. Copyright © 2017. Published by Elsevier Ltd.

Simulation and analysis of different adiabatic Compressed Air Energy Storage plant configurations

International Nuclear Information System (INIS)

Hartmann, Niklas; Vöhringer, O.; Kruck, C.; Eltrop, L.

2012-01-01

Highlights: ► We modeled several configurations of an adiabatic Compressed Air Energy Storage (CAES) plant. ► We analyzed changes in efficiency of these configurations under varying operating conditions. ► The efficiency of the adiabatic CAES plant can reach about 70% for the isentropic configuration. ► In the polytropic case, the efficiency is about 10% lower (at about 60%) than in the isentropic configuration. ► The efficiency is highest for a two-stage CAES configuration and highly dependent on the cooling and heating demand. - Abstract: In this paper, the efficiency of one full charging and discharging cycle of several adiabatic Compressed Air Energy Storage (CAES) configurations are analyzed with the help of an energy balance. In the second step main driving factors for the efficiency of the CAES configurations are examined with the help of sensitivity analysis. The results show that the efficiency of the polytropic configuration is about 60%, which is considerable lower than literature values of an adiabatic CAES of about 70%. The high value of 70% is only reached for the isentropic (ideal) configuration. Key element to improve the efficiency is to develop high temperature thermal storages (>600 °C) and temperature resistant materials for compressors. The highest efficiency is delivered by the two-stage adiabatic CAES configuration. In this case the efficiency varies between 52% and 62%, depending on the cooling and heating demand. If the cooling is achieved by natural sources (such as a river), a realistic estimation of the efficiency of adiabatic Compressed Air Energy Storages (without any greenhouse gas emissions due to fuel consumption) is about 60%.

Criteria for calculating the efficiency of HEPA filters during and after design basis accidents

International Nuclear Information System (INIS)

Bergman, W.; First, M.W.; Anderson, W.L.; Gilbert, H.; Jacox, J.W.

1994-12-01

We have reviewed the literature on the performance of high efficiency particulate air (HEPA) filters under normal and abnormal conditions to establish criteria for calculating the efficiency of HEPA filters in a DOE nonreactor nuclear facility during and after a Design Basis Accident (DBA). The literature review included the performance of new filters and parameters that may cause deterioration in the filter performance such as filter age, radiation, corrosive chemicals, seismic and rough handling, high temperature, moisture, particle clogging, high air flow and pressure pulses. The deterioration of the filter efficiency depends on the exposure parameters; in severe exposure conditions the filter will be structurally damaged and have a residual efficiency of 0%. Despite the many studies on HEPA filter performance under adverse conditions, there are large gaps and limitations in the data that introduce significant error in the estimates of HEPA filter efficiencies under DBA conditions. Because of this limitation, conservative values of filter efficiency were chosen when there was insufficient data

Air/liquid collectors

DEFF Research Database (Denmark)

Jensen, Søren Østergaard; Olesen, Ole; Kristiansen, Finn Harken

1997-01-01

this kind of collectors. The modified simulation program has been used for the determination of the surplus in performance which solar heating systems with this type of solar collectors for combined preheating of ventilation air and domestic hot water will have. The simulation program and the efficiency......This report determine efficiency equations for combined air/liquid solar collectors by measurements on to different air/liquid collectors. Equations which contain all relevant informations on the solar collectors. A simulation program (Kviksol) has been modified in order to be able to handle...

Prediction and design of efficient exciplex emitters for high-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes.

Science.gov (United States)

Liu, Xiao-Ke; Chen, Zhan; Zheng, Cai-Jun; Liu, Chuan-Lin; Lee, Chun-Sing; Li, Fan; Ou, Xue-Mei; Zhang, Xiao-Hong

2015-04-08

High-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes based on exciplex emitters are demonstrated. The best device, based on a TAPC:DPTPCz emitter, shows a high external quantum efficiency of 15.4%. Strategies for predicting and designing efficient exciplex emitters are also provided. This approach allow prediction and design of efficient exciplex emitters for achieving high-efficiency organic light-emitting diodes, for future use in displays and lighting applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.