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Sample records for abstract air thermal

  1. Mercury and Air Pollution: A Bibliography With Abstracts.

    Environmental Protection Agency, Research Triangle Park, NC. Office of Air Programs.

    The Air Pollution Technical Information Center (APTIC) of the Office of Air Programs has selected and compiled this bibliography of abstracts on mercury and air pollution. The abstracted documents are considered representative of available literature, although not all-inclusive. They are grouped into eleven categories: (1) Emission Sources, (2)…

  2. 2015 German refrigeration and air conditioning meeting. Abstracts

    The volume contains the abstracts of the 2015 German refrigeration and air conditioning meeting in 5 chapters: cryo-technology, fundamentals of materials for refrigeration engineering and heat pump technology, facilities and components for the refrigeration and heat pump technology; application of refrigeration engineering; air conditioning technology and heat pump application.

  3. Solar thermal heating and cooling. A bibliography with abstracts

    Arenson, M.

    1979-01-01

    This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

  4. Abstraction of Thermal Hydrology and Coupled Processes for TSPA

    The thermal-hydrologic (TH) and coupled process models describe the evolution of a potential geologic repository as heat is released from emplaced waste. The evolution (thermal, hydrologic, chemical, and mechanical) of the engineered barrier and geologic systems is heavily dependent on the heat released by the waste packages and how the heat is transferred from the emplaced wastes through the drifts and through the repository host rock. The essential elements of this process are extracted (or abstracted) from the process-level models that incorporate the basic energy and mass conservation principles and applied to the total system models used to describe the overall performance of the potential repository. The process of total system performance assessment (TSPA) abstraction is the following. First is a description of the parameter inputs used in the process-level models. A brief description is given hereof past inputs for the viability assessment (e.g., for TSPA-VA) and current inputs for the site recommendation (TSPA-SR). This is followed by a highlight of the process-level models from which the abstractions are made. These include descriptions of TH, thermal-hydrologic-chemical (THC), and thermal-mechanical (TM) processes used to describe the performance of individual waste packages and waste emplacement drifts as well as the repository as a whole. Next is a description of what (and how) information is abstracted from the process-level models. This also includes an accounting of the features, events, and processes (FEPs) that are important to both the regulators and the international repository community in general. Finally, an identification of the TSPA model components that utilize the abstracted information to characterize the overall performance of a potential geologic repository is given

  5. ABSTRACTS

    2011-01-01

    A Preliminary Inquiry into the Intellectual Origins of Li Dazhao's My Idea of Marxism Abstract ;By translingual-textual comparison, this paper attempts to make a preliminary inquiry into the intellectual origins of Li Dazhao's My Idea of Marxism, suggesting that Li's article, instead of being "a complete copy" of the Japanese scholar

  6. Abstracts

    2011-01-01

    The Western Theories of War Ethics and Contemporary Controversies Li Xiaodong U Ruijing (4) [ Abstract] In the field of international relations, war ethics is a concept with distinct westem ideological color. Due to factors of history and reality, the in

  7. Abstract

    2012-01-01

    Cognitive Structure of Scientific Theory in the Scientist-Philosopher's Eyes、Two Theories of Scientific Abstraction Centered on Practices、Many-worlds Interpretation in Quantum Measurement and Its Meaning、Scientific Instrument: Paradigm Shift from Instrumentalism to Realism and Phenomenology

  8. Abstracts

    2011-01-01

    [ Abstract ] The global resurgence of religion and the return of religion from the so-call "Westphalia Exile" to the central stage of international religions have significantly trans- formed the viewpoints of both media and academia toward the role of religion in IR, and the challenges posed by religion to the contemporary international relations are often described as entirely subversive. The author argues that as a second-tier factor in most countries' for- eign policies and international affairs,

  9. ABSTRACTS

    2012-01-01

    (1) Lenin's "Unity of Three Dialectics": Notes Science of Logic and The Capital on Philosophy in the Dual Contexts of Sun Zhengyu 4 Lenin's dialectics in Notes on Philosophy is essentially a unity of materialistic logic, dialectics and epistemology that has arisen from interactions between Hegel' s Science of Logic and Marx' s The Capital. Due to a lack of understanding of Lenin' s "unity of three dialectics," people tend to misunderstand his dialectics for the meeting of two extremes of the "sum total of living instances" and "abstract methods,

  10. ABSTRACT

    2011-01-01

    --Based on of Marx's Economic Philosophy Manuscripts of 1844 HE Jian-jin (Philosophy Department, Fujian Provincial Committee Party School, Fuzhou, Fujian 350012, China) Abstract: Socialism with Chinese characteristics has a close relationship with the return and growth of capital in China. To implement the scientific concept of development, we must confront the problem of scientifically controlling the capital. In Economic and Philosophical Manuscripts of 1844, Marx criticized the three old philosophical thinking of treating capital: Object-oriented thinking, intuitive thinking, purely spiritual abstract thinking, and he established his own unique understanding of the capital that is to understand the capital from the human perceptual activities and practical activities. Contemporary Chinese society exist the problem of underdevelopment and abnormal development, and the three heterogeneity problems of pre-modern, modern, postmodern concurrent. In order to implement the scientific concept of development, we must reject any abstract positive or negative to modern basic principles under the guidance of the capital, against the eternal capital theory and capital theory of evil, and we must oppose the thinking that the capital is eternal or evil. Key words: socialism with Chinese characteristics; capital; national economics; scientific concept of development

  11. ABSTRACTS

    2012-01-01

    On Rousseau's Equality and Freedom GONG Qun Abstract:Equality and freedom are the two core concepts of political philosophy and Rousseau~s political philosophy is no exception. Freedom and equality in Rousseau in- cludes two levels: natural state and social state under social contract, and among them, there is one state of un-equality. The relationship between the two concepts here is that equality is a necessary precondition of freedom, and that there is no equality, there is no freedom. The achievement of Rousseau~s equality is by one contractual behavior that all the members transfer their rights, especially property rights, and form of the Community. Freedom in Rousseau's mind is through the people's sovereignty in the Community to achieve freedom.

  12. ABSTRACTS

    2012-01-01

    The Relation between Individuals and Work Units in Stated-Owned Enterprises in Economic Transitional Pe- riod: Changes and their Influences Abstract: As a representation of extinction of work unit system, some dramatic changes have taken place on the rela- tion between individuals and work units in state-owned enterprises. Among many changes are the radical change of the way work unit stimulating and controlling its employees, the extinction of previous system supported by "work unit people", a tense relation between the employees and the work unit caused by the enterprise' s over-pursuit of performance. These changes result in such problems as grievous inequality, violation of personal interest, lack of mechanism for employees' voices and their low sense of belonging, which has brought unprecedented challenges for business administration and corpo- ration euhure development in China. Keywords: danwei/work unit; stimulate and control; relation between individuals and work units; work unit people

  13. Abstracts

    2012-01-01

    The Western Characteristics of the Pardims of International Studies in America:With the Huaxla System as a Counterexample Ye Zicheng (4)[ Abstract ] Three flaws are obvious in the three paradigms of International Studies in America. Specifically, their arguments are based on the assumption that the world is anarchic ; they go too far in employing the scientific and rational methodology; they pay little attention to the humans. Hence, the three paradigms of international studies in America aren' t necessarily useful for the explanation of China' s history and culture as well as its relations with the outside world. The Huaxia system, for example, is anarchic but also apparently hierarchical; the approach of pursuing security in understanding the rise of western powers may be meaningless, for the hegemony in the Huaxia System needn't worry about its security; the theory of power-balancing seemingly couldn' t explain why Qin ended up in defeating the alliance of the other six states in the Warring-states period. The Huaxia system is quite open, and has free movement of people, goods, and ideas. Some interstate regimes and institutions were formed through Huimeng (alliance-making) among states. However, this kind of limited and fragile interdependence and cooperation soon came to an end after the hegemonies of Qi, Jin and Wei. There does exit the identity problem among states in the Huaxia System, but this problem doesn't play such a great role as the constructivists expect it would.

  14. ABSTRACTS

    2012-01-01

    Discussions of Design Highlights for Tailgas Treatment in Sulphuric Acid Plant Using New Technology for Flue Gas Desulfurization Through Catalytic Reduction LI Xin , CAO Long-wen , YIN Hua-qiang , El Yue-li , LI Jian-iun ( 1 ,College of Architecture and Environment, Sichuan University, Chengdu 610065, China;2 ,Daye Nonferrous Metals Co., Ltd., Huangshi 435000, China; 3 ,Tile Sixth Construction Company Ltd. of China National Chemical Engineering Corp., Xiangfan 441021, China) Abstract : For the present situation of tailgas treatment in current sulphuric acid plants and existing problems with commonly used technologies, the fun- damental working principle, process flow and reference project for a new technology for flue gas desulfurization through catalytic redaction which is used for tailgas treatment in a sulphuric acid plant and recovery of sulphur resource are outlined. The design highlights of this technology are analyzed and the are proposed. Compared to conventional technologies, this new technology offers high desulfurization efficiency and unique technology, which can effectively tackle the difficuhies of tailgas treatment in sulphuric acid plants after enforcement of the new standard. This new technology is thought to be significant economic benefit, environmental benefit, as well as a promising future of application.

  15. Abstracts

    2012-01-01

    Strategic Realism: An Option for China' s Grand Strategy Song Dexing (4) [ Abstract] As a non-Western emerging power, China should positively adapt its grand strategy to the strategic psychological traits in the 21st century, maintain a realist tone consistent with the national conditions of China, and avoid adventurist policies while awaring both strategic strength and weakness. In the 21st century, China' s grand strategy should be based on such core values as security, development, peace and justice, especially focusing on development in particular, which we named "strategic realism". Given the profound changes in China and the world, strategic realism encourages active foreign policy to safe- guard the long-term national interests of China. Following the self-help logic and the fun- damental values of security and prosperity, strategic realism concerns national interests as its top-priority. It advocates smart use of power, and aims to achieve its objectives by optimizing both domestic and international conditions. From the perspective of diplomatic phi- losophy, strategic realism is not a summarization of concrete policies but a description of China' s grand strategy orientations in the new century. [ Key Words] China, grand strategy, strategic realism [ Author]Song Dexing, Professor, Ph.D. Supervisor, and Director of the Center for International Strategic Studies, University of International Studies of PLA.

  16. Abstracts

    2012-01-01

    [Abstract] The essay analyzed the action logic of hegemon with a power approach. Hegemony can be classified as benign or malignant. A benign hegemon should be pro- ductive, inclusive and maintain procedure justice when it uses its power. The power of hegemon can be categorized into two types: the hard power, which is the use of coer- cion and payment and can be measured by public products, and the soft power, which shows the ability to attract and co-opt and can be measured by the relationship-specific investments. The relationship between the input of public products and the relationship -specific investments is not positively correlative. Confusing with the public products and the soft power might lead to strategic misleading. A country rich in power re- sources should comply with the following principles if it wanted to improve its hard power and soft power: first, analyze the scope of the existing hegemon's soft power and avoid investing public products in the scope; second, maintain honesty in a long term and continue to increase others' benefits following the rule of neutral Pareto im- provement; third, provide both public goods and public bads; fourth, be more patient to obtain soft power. [ Key Words] hegemon, soft power, relationship-specific investment, strategic misleading [Authors]Feng Weijiang, Ph.D., Associate Professor, Institute of World Economics and Politics, Chinese Academy of Social Science; Yu Jieya, Master, PBC Shanghai Headquarters.

  17. Thermal oxidation for air toxics control

    The Administration projects annual expenditures of $1.1 billion by 1995, increasing to $6.7 billion by 2005, in order to comply with the new Clean Air Act Title III hazardous air pollutant requirements. The Title III requirements include 189 hazardous air pollutants which must be reduced or eliminated by 2003. Twenty of the 189 listed pollutants account for approximately 75 percent of all hazardous air pollutant emissions. Ninety percent of these 20 pollutants can be effectively controlled through one or mote of the thermal oxidation technologies. This paper reports that the advantages and disadvantages of each thermal oxidation technology vary substantially and must be reviewed for each application in order to establish the most effective thermal oxidation solution. Effective thermal oxidation will meet MACT (maximum achievable control technology) emission standards

  18. Scientific-technical conference Thermal physics of fast reactors (Thermal physics-2014). Book of abstracts

    In the book of abstracts there are the materials of investigations related with scientific and technical justification of new generation fast reactors with different liquid metal coolants. Consideration is given to the thermophysical problems in the field of hydrodynamics and heat transfer in flow path and components of reactor installations; thermophysical properties and physicochemical processes in the systems liquid metal - structural material - inert gas; development and verification of thermophysical calculating codes, numerical simulation of thermophysical processes in nuclear power installations. Considerable attention is paid to liquid metal coolant technologies. The use of fast reactors for non-power applications and liquid metal coolants in non-nuclear technologies is discussed

  19. Scientific-technical conference Thermal physics of new generation reactors (Thermal physics-2015). Book of abstracts

    In the book of abstracts there are the materials connected with justification of new design solutions directed on increasing efficiency and safety of projects of both water-cooled and new generation fast reactors with sodium and lead coolants. Wide range of thermophysical problems in the field of hydrodynamics and heat transfer in flow path and equipment components of reactor facilities, experimental and numerical simulation of accident processes evolution are under consideration. There are the materials on the questions of thermophysical properties of coolants and physicochemical processes in the systems liquid metal - inert gas - structural materials, thermophysical calculational codes development and verification, nuclear power facility thermophysical calculations. Great attention is paid to development of methods and means of control and purification of liquid metal coolants from impurities. The problems of innovation supercritical water-cooled power nuclear reactors are discussed as well as the suggestions on liquid metal coolants in different branches of industry

  20. THERMAL ANALYSIS OF EARTH AIR HEAT EXCHANGER USING CFD

    Vaibhav Madane; Meeta Vedpathak

    2015-01-01

    This project focuses on Earth Air Heat Exchanger which is reducing energy consumption in a building. The air is passing through the buried tubes and heat exchange takes place between air and surrounding soil. This equipment helps to reduce energy consumption of an air conditioning unit. This project analyses the thermal performance of earth air heat exchanger by using computational fluid dynamics modeling. The model is validated against experimental observations and investigations...

  1. Overall energy, exergy and carbon credit analysis by different type of hybrid photovoltaic thermal air collectors

    Highlights: ► Comparative study of PVT air collectors. ► CO2 analysis of all type of PVT air collectors. ► Study of thermal energy, exergy gain and exergy efficiency. ► Exergy efficiency of unglazed hybrid PVT tiles air collector is most efficient. - Abstract: In this paper, comparative analysis of different type of photovoltaic thermal (PVT) air collector namely: (i) unglazed hybrid PVT tiles, (ii) glazed hybrid PVT tiles and (iii) conventional hybrid PVT air collectors have been carried out for the composite climate of Srinagar (India). The comparative study has been carried out in terms of overall thermal energy and exergy gain, exergy efficiency and carbon credit earned by different type of hybrid PVT air collectors. It has been observed that overall annual thermal energy and exergy gain of unglazed hybrid PVT tiles air collector is higher by 27% and 29.3% respectively as compared to glazed hybrid PVT tiles air collector and by 61% and 59.8% respectively as compared to conventional hybrid PVT air collector. It has also been observed that overall annual exergy efficiency of unglazed and glazed hybrid PVT tiles air collector is higher by 9.6% and 53.8% respectively as compared to conventional hybrid PVT air collector. On the basis of comparative study, it has been concluded that CO2 emission reduction per annum on the basis of overall thermal energy gain of unglazed and glazed hybrid PVT tiles air collector is higher by 62.3% and 27.7% respectively as compared to conventional hybrid PVT air collector and on the basis of overall exergy gain it is 59.7% and 22.7%.

  2. Use of Structure as a Basis for Abstraction in Air Traffic Control

    Davison, Hayley J.; Hansman, R. John

    2004-01-01

    The safety and efficiency of the air traffic control domain is highly dependent on the capabilities and limitations of its human controllers. Past research has indicated that structure provided by the airspace and procedures could aid in simplifying the controllers cognitive tasks. In this paper, observations, interviews, voice command data analyses, and radar analyses were conducted at the Boston Terminal Route Control (TRACON) facility to determine if there was evidence of controllers using structure to simplify their cognitive processes. The data suggest that controllers do use structure-based abstractions to simplify their cognitive processes, particularly the projection task. How structure simplifies the projection task and the implications of understanding the benefits structure provides to the projection task was discussed.

  3. The Impact of Air Exchange Effectiveness on Thermal Comfort in an Air-Conditioned Office

    Roonak Daghigh

    2009-01-01

    Full Text Available Problem statement: Impact of air exchange effectiveness on thermal comfort has not been investigated and, therefore, not well understood .Therefore, the influence of air exchange effectiveness on thermal comfort is investigated in this study. Approach: The main objective of this research is to investigate the thermal comfort level of an air-conditioned office room under 14 windows-door opening arrangements as a function of maximum, minimum and mean Air Exchange Effectiveness (AEE, as has not been inquired into already. The tracer gas decay method has been applied during the experimental procedures to estimate air exchange effectiveness, on the basis of room average and local mean age of air. Simultaneously, thermal comfort variables were measured and through these data, the thermal comforts Fanger's indices (PMV and PPD were calculated. Staff answered a survey on their sensation of the indoor climate. Results: Results of 60 survey responses to thermal comfort questions in office and indoor air quality are presented. This study has shown that there are relationship between AEE and thermal comfort and three linear regression equations of PMV versus AEE can be derived for this air-conditioned office. Conclusion: Studies on the effect of air exchange effectiveness on thermal comfort in an office have shown that Thermal comfort is influenced by AEE, which go beyond the six factors which have been taken into account in PMV modeling.

  4. Thermal stratification level of low sidewall air supply with air-conditioning system in large space

    黄晨; 蔡宁; 高雪垒

    2009-01-01

    The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m.

  5. Thermal decay in underfloor air distribution (UFAD) systems: Fundamentals and influence on system performance

    Graphical abstract: Surface heat transfer breakdown for an underfloor air distribution (UFAD) system supply plenum. Highlights: ► Thermal decay of a UFAD system is considerable (annual median = 3.7 K). ► Thermal decay is driven by heat transfer through both the concrete slab and the raised floor. ► Thermal decay may lead to higher airflow rates and increased fan and chiller energy consumption. -- Abstract: Underfloor air distribution (UFAD) is a mechanical ventilation strategy in which the conditioned air is primarily delivered to the zone from a pressurized plenum through floor mounted diffusers. Compared to conventional overhead (OH) mixing systems, UFAD has several potential advantages, such as improved thermal comfort and indoor air quality (IAQ), layout flexibility, reduced life cycle costs and improved energy efficiency in suitable climates. In ducted OH systems designers have reasonably accurate control of the diffuser supply temperature, while in UFAD this temperature is difficult to predict due to the heat gain of the conditioned air in the supply plenum. The increase in temperature between the air entering the plenum and air leaving through a diffuser is known as thermal decay. In this study, the detailed whole-building energy simulation program, EnergyPlus, was used to explain the fundamentals of thermal decay, to investigate its influence on energy consumption and to study the parameters that affect thermal decay. It turns out that the temperature rise is considerable (annual median = 3.7 K, with 50% of the values between 2.4 and 4.7 K based on annual simulations). Compared to an idealized simulated UFAD case with no thermal decay, elevated diffuser air temperatures can lead to higher supply airflow rate and increased fan and chiller energy consumption. The thermal decay in summer is higher than in winter and it also depends on the climate. The ground floor with a slab on grade has less temperature rise compared to middle and top floors. An

  6. Solar Air Heaters with Thermal Heat Storages

    Abhishek Saxena; Varun Goel

    2013-01-01

    Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has be...

  7. An improved thermal and electrical model for a solar photovoltaic thermal (PV/T) air collector

    In this paper, an attempt is made to investigate the thermal and electrical performance of a solar photovoltaic thermal (PV/T) air collector. A detailed thermal and electrical model is developed to calculate the thermal and electrical parameters of a typical PV/T air collector. The thermal and electrical parameters of a PV/T air collector include solar cell temperature, back surface temperature, outlet air temperature, open-circuit voltage, short-circuit current, maximum power point voltage, maximum power point current, etc. Some corrections are done on heat loss coefficients in order to improve the thermal model of a PV/T air collector. A better electrical model is used to increase the calculations precision of PV/T air collector electrical parameters. Unlike the conventional electrical models used in the previous literature, the electrical model presented in this paper can estimate the electrical parameters of a PV/T air collector such as open-circuit voltage, short-circuit current, maximum power point voltage, and maximum power point current. Further, an analytical expression for the overall energy efficiency of a PV/T air collector is derived in terms of thermal, electrical, design and climatic parameters. A computer simulation program is developed in order to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Finally, parametric studies have been carried out. Since some corrections have been down on thermal and electrical models, it is observed that the thermal and electrical simulation results obtained in this paper is more precise than the one given by the previous literature. It is also found that the thermal efficiency, electrical efficiency and overall energy efficiency of PV/T air collector is about 17.18%, 10.01% and 45%, respectively, for a sample climatic, operating and design parameters.

  8. Thermal modelling of the cathode in air-breathing PEM fuel cells

    Highlights: • A thermal two-dimensional model was developed for an air-breathing PEM fuel cell. • The neglect of Joule heating may significantly underestimate the thermal parameters. • Compared to Joule heating, the thermal parameters are less sensitive to the entropic heat. • Heat is dissipated poorly if the fuel cell is oriented horizontally facing downwards. - Abstract: A thermal two-dimensional model has been built for an air-breathing proton exchange membrane (PEM) fuel cell that has been reported in the literature. The objective of the study is to investigate the thermal situation over the cathode surface of the fuel cell. The Joule heating was found to be significant and therefore it must be incorporated into the model, especially at high current densities. Such incorporation leads to a more accurate estimation of the heat transfer coefficient, which is a major performance indicator for air-breathing PEM fuel cells. The heat transfer coefficient was found to be less sensitive to the entropic heat of the fuel cell; however, this effect cannot be overlooked, especially at low current densities. Finally, the orientation was shown to have a significant effect on the thermal dissipation from the air-breathing PEM fuel cells: the heat is dissipated far more effectively if the fuel cell is oriented vertically or horizontally facing upwards than if it is oriented horizontally facing downwards

  9. Thermal analysis of car air conditioning

    Trzebiński, Daniel; Szczygieł, Ireneusz

    2010-10-01

    Thermodynamic analysis of car air cooler is presented in this paper. Typical refrigerator cycles are studied. The first: with uncontrolled orifice and non controlled compressor and the second one with the thermostatic controlled expansion valve and externally controlled compressor. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system; was analysed. Also, its effectiveness and the power required to drive the compressor were investigated. The impact of improper refrigerant charge on the performance of air conditioning systems was also checked.

  10. Determination of thermal performance of solar air heater

    Kozak, Christina; Zhelykh, Vasil

    2013-01-01

    Considered the basic aspects of passive solar building. Given the main types of solar air heating systems. Proposed heating and ventilation system at the basis of solar air heater. Constructed fourfactors nomohram for determining thermal power of the thermosiphon heliocollector. Obtained analytical dependence of the amount heat of thermo heliocollector from the differential temprature air inlet and outlet, of the area input and output apertures of solar collector, heat fl...

  11. Thermal analysis of air-cooled fuel cells

    Shahsavari, Setareh

    2011-01-01

    Temperature distribution in a fuel cell significantly affects the performance and efficiency of the fuel cell system. Particularly, in low temperature fuel cells, improvement of the system requires proper thermal management, which indicates the need for developing accurate thermal models. In this study, a 3D numerical thermal model is presented to analyze the heat transfer and predict the temperature distribution in air-cooled proton exchange membrane fuel cells (PEMFC). In the modeled fuel c...

  12. Thermal Analysis of Air-Core Power Reactors

    Zhao Yuan; Jun-jia He; Yuan Pan; Xiao-gen Yin; Can Ding; Shao-fei Ning; Hong-lei Li

    2013-01-01

    A fluid-thermal coupled analysis based on FEM is conducted. The inner structure of the coils is built with consideration of both the structural details and the simplicity; thus, the detailed heat conduction process is coupled with the computational fluid dynamics in the thermal computation of air-core reactors. According to the simulation results, 2D temperature distribution results are given and proved by the thermal test results of a prototype. Then the temperature results are used to calcu...

  13. Performance analysis of a hybrid photovoltaic thermal solar air heater

    A photovoltaic (PV/T) air heater is a collector that combines thermal and photovoltaic systems in one single hybrid generating unit. It generators both thermal and electrical energies simultaneously. A new design of a double-pass photovoltaic-thermal solar air collector with CPC and fins was successfully developed and fabricated at Universiti Kebangsaam Malaysia. This collector tested under actual environmental conditions to study its performance over a range of operating conditions. The test set-up, instrumentation and measurement are described further. It was found that the performance of the collector was in agreement with the theoretical prediction. Results of the outdoors test are presented and discussed(Author)

  14. Perceived air quality, thermal comfort, and SBS symptoms at low air temperature and increased radiant temperature

    Toftum, Jørn; Reimann, Gregers Peter; Foldbjerg, P.;

    2002-01-01

    This study investigated if low air temperature, which is known to improve the perception of air quality, also can reduce the intensity of some SBS symptoms. In a low-polluting office, human subjects were exposed to air at two temperatures 23 deg.C and 18 deg.C both with and without a pollution...... source present at the low temperature. To maintain overall thermal neutrality, the low air temperature was partly compensated for by individually controlled radiant heating, and partly by allowing subjects to modify clothing insulation. A reduction of the air temperature from 23 deg.C to 18 deg.......C suggested an improvement of the perceived air quality, while no systematic effect on symptom intensity was observed. The overall indoor environment was evaluated equally acceptable at both temperatures due to local thermal discomfort at the low air temperature....

  15. Effect of Air Velocity on Thermal Comfort under Thermal Environment Ramp Changing

    嵇赟喆; 涂光备; 孙琳

    2004-01-01

    Set points of the indoor air temperature and relative humidity in short-term staying location were studied. In this condition, the thermal reaction of human body varied with the ramp changes of the environmental thermal parameters.The change rules of about 60 subjects'thermal reaction to the ramp change of environment were surveyed, and the effect of air movement on the thermal reaction during transient condition was considered by using a questionnaire. With the experimental results and research findings under stable condition, a way to set environmental parameters of short-time staying location was recommended.

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

    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 m3/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

  17. Plug and Play web-based visualization of mobile air monitoring data (Abstract)

    EPA’s Real-Time Geospatial (RETIGO) Data Viewer web-based tool is a new program reducing the technical barrier to visualize and understand geospatial air data time series collected using wearable, bicycle-mounted, or vehicle-mounted air sensors. The RETIGO tool, with anticipated...

  18. Steady Thermal Field Simulation of Forced Air-cooled Column-type Air-core Reactor

    DENG Qiu; LI Zhenbiao; YIN Xiaogen; YUAN Zhao

    2013-01-01

    Modeling the steady thermal field of the column-type air-core reactor,and further analyzing its distribution regularity,will help optimizing reactor design as well as improving its quality.The operation mechanism and inner insulation structure of a novel current limiting column-type air-core reactor is introduced in this paper.The finite element model of five encapsulation forced air-cooled column type air-core reactor is constructed using Fluent.Most importantly,this paper present a new method that,the steady thermal field of reactor working under forced air-cooled condition is simulated without arbitrarily defining the convection heat transfer coefficient for the initial condition; The result of the thermal field distribution shows that,the maximum steady temperature rise of forced air-cooled columntype air-core reactor happens approximately 5% to its top.The law of temperature distribution indicates:In the 1/3part of the reactor to its bottom,the temperature will rise rapidly to the increasing of height,yet the gradient rate is gradually decreasing; In the 5 % part of the reactor to its top,the temperature will drop rapidly to the increasing of height; In the part between,the temperature will rise slowly to the increasing of height.The conclusion draws that more thermal withstand capacity should be considered at the 5 % part of the reactor to its top to achieve optimal design solution.

  19. Predicted thermal superluminescence in low-pressure air

    Aramyan, A. R.; Haroyan, K. P.; Galechyan, G. A.; Mangasaryan, N. R.; Nersisyan, H. B.

    2009-01-01

    It is shown that due to the dissociation of the molecular oxygen it is possible to obtain inverted population in low pressure air by heating. As a result of the quenching of the corresponding levels of the atomic oxygen the thermal superluminescent radiation is generated. It has been found that the threshold of the overpopulation is exceeded at the air temperature 2300-3000 K. Using this effect a possible mechanism for the generation of the flashes of the radiation in air observed on the airf...

  20. Predicted thermal superluminescence in low-pressure air

    Aramyan, A R; Galechyan, G A; Mangasaryan, N R; Nersisyan, H B

    2009-01-01

    It is shown that due to the dissociation of the molecular oxygen it is possible to obtain inverted population in low pressure air by heating. As a result of the quenching of the corresponding levels of the atomic oxygen the thermal superluminescent radiation is generated. It has been found that the threshold of the overpopulation is exceeded at the air temperature 2300-3000 K. Using this effect a possible mechanism for the generation of the flashes of the radiation in air observed on the airframe of the space shuttle during its descent and reentry in the atmosphere is suggested.

  1. Thermal computations for electronics conductive, radiative, and convective air cooling

    Ellison, Gordon

    2010-01-01

    IntroductionPrimary mechanisms of heat flowConductionApplication example: Silicon chip resistance calculationConvectionApplication example: Chassis panel cooled by natural convectionRadiationApplication example: Chassis panel cooled only by radiation 7Illustrative example: Simple thermal network model for a heat sinked power transistorIllustrative example: Thermal network circuit for a printed circuit boardCompact component modelsIllustrative example: Pressure and thermal circuits for a forced air cooled enclosureIllustrative example: A single chip package on a printed circuit board-the proble

  2. Proceedings of the twentieth DAE-BRNS symposium on thermal analysis: book of abstracts

    The topics covered in this symposium are: thermodynamics and phase diagram studies, thermochemical and thermophysical properties of materials, solid-state reactions and kinetics, thermal properties of ceramics and cermets, thermal behaviour of nanomaterials and coated particles and thermal analysis of materials. Papers relevant to INIS are indexed separately

  3. A dynamic model for air-based photovoltaic thermal systems working under real operating conditions

    Highlights: • A dynamic model suitable for air-based photovoltaic thermal (PVT) systems is presented. • The model is validated with PVT data from two unique buildings. • The simulated output variables match very well with the experimental data. • The performance of the PVT system under changing working condition is analysed. - Abstract: In this paper a dynamic model suitable for simulating real operating conditions of air-based photovoltaic thermal (PVT) systems is presented. The performance of the model is validated by using the operational data collected from the building integrated photovoltaic (PVT) systems installed in two unique buildings. The modelled air outlet temperature and electrical power match very well with the experimental data. In Solar Decathlon house PVT, the average (RMS) error in air outlet temperatures was 4.2%. The average (RMS) error in electrical power was also 4.2%. In the Sustainable Buildings Research Centre PVT, the average errors (RMS) of PV and air temperatures were 3.8% and 2.2%, respectively. The performance of the PVT system under changing working condition is also analysed in this paper. The analysis includes the effect of ambient air temperature, air inlet temperature, air flow rate and solar irradiation on thermal, electrical, first law and second law efficiencies. Both the thermal and the 1st law efficiencies almost linearly increased with the increase of the ambient temperature. However, the PVT electrical efficiency and the second law efficiency decreased with the increase of the ambient temperature. All efficiencies expect the second law efficiency decreased with increase of the PVT air inlet temperature. The second law efficiency first increased and then reduced. With increasing the air flow rate all the efficiencies increased. The electrical and second law efficiencies become less sensitive when the air flow rate exceeded 300 l/s. Both the thermal and the 1st law efficiencies decreased while the electrical

  4. A solar air collector with integrated latent heat thermal storage

    Charvat, Pavel; Ostry, Milan; Mauder, Tomas; Klimes, Lubomir

    2012-04-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data).

  5. A solar air collector with integrated latent heat thermal storage

    Klimes Lubomir

    2012-04-01

    Full Text Available Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data.

  6. Thermal conditions and perceived air quality in an air-conditioned auditorium

    Polednik, Bernard; Guz, Łukasz; Skwarczyński, Mariusz; Dudzińska, Marzenna R.

    2016-07-01

    The study reports measurements of indoor air temperature (T) and relative humidity (RH), perceived air quality (PAQ) and CO2, fine aerosol particle number (PN) and mass (PM1) concentrations in an air conditioned auditorium. The measurements of these air physical parameters have been carried out in the unoccupied auditorium with the air conditioning system switched off (AC off mode) and in the unoccupied and occupied auditorium with the air conditioning system switched off during the night and switched on during the day (AC on/off mode). The average indoor air thermal parameters, CO2 concentration and the PAQ value (in decipols) were elevated, while average PM1 concentration was lower in the AC on/off mode. A statistically significant (p r = 0.66 and r = 0.59, respectively) in that AC mode. A significant negative correlation has been observed between T and PN and PM1 concentrations (r = -0.38 and r = -0.49, respectively). In the AC off mode the above relations between T and the particle concentrations were not that unequivocal. These findings may be of importance as they indicate that in certain AC operation modes the indoor air quality deteriorates along with the variation of the indoor air microclimate and room occupation. This, in turn, may adversely affect the comfort and productivity of the users of air conditioned premises.

  7. A solar air collector with integrated latent heat thermal storage

    Klimes Lubomir; Mauder Tomas; Ostry Milan; Charvat Pavel

    2012-01-01

    Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM) was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage...

  8. Thermal efficiency of single-pass solar air collector

    Ibrahim, Zamry; Ibarahim, Zahari; Yatim, Baharudin [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); Ruslan, Mohd Hafidz [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2013-11-27

    Efficiency of a finned single-pass solar air collector was studied. This paper presents the experimental study to investigate the effect of solar radiation and mass flow rate on efficiency. The fins attached at the back of absorbing plate to improve the thermal efficiency of the system. The results show that the efficiency is increased proportional to solar radiation and mass flow rate. Efficiency of the collector archived steady state when reach to certain value or can be said the maximum performance.

  9. Thermodynamic model of a thermal storage air conditioning system with dynamic behavior

    Highlights: • We developed an automotive thermal storage air conditioning system model. • The thermal storage unit utilizes phase change materials. • We use semi-analytic solution to the coupled phase change and forced convection. • We model the airside heat exchange using the NTU method. • The system model can incorporate dynamic inputs, e.g. variable inlet airflow. - Abstract: A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system’s dynamic behavior, such as a dynamic air flow rate into the vehicle’s cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle’s cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid–air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semi-analytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid–air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system

  10. Numerical Analysis of Thermal Comfort at Open Air Spaces

    Papakonstantinou, K.; Belias, C.; Pantos-Kikkos, S.; Assana, A.

    2008-09-01

    The present paper refers to the numerical simulation of air velocity at open air spaces and the conducting thermal comfort after the evaluation of the examined space using CFD methods, taking into account bioclimatic principles at the architectural design. More specially, the paper draws attention to the physical procedures governing air movement at an open environment area in Athens (urban park), named "Attiko Alsos," trying to form them in such way that will lead to the thermal comfort of the area's visitors. The study presents a mathematical model, implemented in a general computer code that can provide detailed information on velocity, prevailing in three-dimensional spaces of any geometrical complexity. Turbulent flow is simulated and buoyancy effects are taken into account. This modelling procedure is intended to contribute to the effort towards designing open areas, such as parks, squares or outdoor building environments, using thermal comfort criteria at the bioclimatic design. A computer model of this kind will provide the architects or the environmental engineers with powerful and economical means of evaluating alternative spaces' designs.

  11. Thermal resistances of air in cavity walls and their effect upon the thermal insulation performance

    Bekkouche, S.M.A.; Cherier, M.K.; Hamdani, M.; Benamrane, N. [Application of Renewable Energies in Arid and Semi Arid Environments /Applied Research Unit on Renewable Energies/ EPST Development Center of Renewable Energies, URAER and B.P. 88, ZI, Gart Taam Ghardaia (Algeria); Benouaz, T. [University of Tlemcen, BP. 119, Tlemcen R.p. 13000 (Algeria); Yaiche, M.R. [Development Center of Renewable Energies, CDER and B.P 62, 16340, Route de l' Observatoire, Bouzareah, Algiers (Algeria)

    2013-07-01

    The optimum thickness in cavity walls in buildings is determined under steady conditions; the heat transfer has been calculated according to ISO 15099:2003. Two forms of masonry units are investigated to conclude the advantage of high thermal emissivity. The paper presents also some results from a study of the thermal insulation performance of air cavities bounded by thin reflective material layer 'eta = 0.05'. The results show that the most economical cavity configuration depends on the thermal emissivity and the insulation material used.

  12. System Level Analysis of a Water PCM HX Integrated Into Orion's Thermal Control System Abstract

    Navarro, Moses; Hansen, Scott; Ungar, Eugene; Sheth, Rubik

    2015-01-01

    In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development an Orion system level analysis was performed using Thermal Desktop for a water PCM HX integrated into Orion's thermal control system and in a 100km Lunar orbit. The study analyzed 1) placing the PCM on the Internal Thermal Control System (ITCS) versus the External Thermal Control System (ETCS) 2) use of 30/70 PGW verses 50/50 PGW and 3) increasing the radiator area in order to reduce PCM freeze times. The analysis showed that for the assumed operating and boundary conditions utilizing a water PCM HX on Orion is not a viable option. Additionally, it was found that the radiator area would have to be increased over 20% in order to have a viable water-based PCM HX.

  13. Evaluation of sectrally-selective materials for multi-layer solar thermal crop drying (abstract)

    Solar thermal (ST) drying is a ubiquitous method in widespread use for fruit and vegetable crop preservation in developing countries; however, it has had limited commercialization in the United States due to concerns about slow drying rates, poor product quality, and predicted low return-on-investme...

  14. Modelling Venting and Pressure Build-up in a 18650 LCO Cell during Thermal Runaway (ABSTRACT)

    Coman, Paul Tiberiu; Veje, Christian; White, Ralph;

    Li-ion batteries are a very popular type of electric storage devices that possess high energy density when compared to the other battery chemistries. Due to this property, when operating under abusive conditions such as high ambient temperature, the batteries can experience thermal runaway, which...

  15. Thermal decomposition kinetics of antimony oxychloride in air

    阳卫军; 唐谟堂; 金胜明

    2002-01-01

    The DTA and XRD techniques were employed to study thermal decomposition mechanism of antimony oxychloride SbOCl in the air. The thermal decomposition reaction occurs in four steps, and the former three steps as: SbOCl(s)→Sb4O5Cl2(s)+SbCl3(g)→Sb8O11Cl2(s)+SbCl3(g)→Sb2O3(s)+SbCl3(g). The forth step is the oxidation of Sb2O3 by air, Sb2O3(s)+O2→Sb2O4(s). The activation energy and the order of the thermal decomposition reaction of antimony oxychloride in three steps presented in DTA curves were calculated according to Kinssinger methods from DTA curves. The values of activation energy and the order are respectively 91.97kJ/mol, 0.73 in the first step, 131.14kJ/mol, 0.63 in the second step and 146.94kJ/mol, 1.58 in the third step.

  16. A hybrid thermal management system for lithium ion batteries combining phase change materials with forced-air cooling

    Highlights: • Heat accumulation in PCM causes failures of passive thermal management systems. • The introduction of forced air convection improves the reliability of PCMs. • Temperature distribution in the hybrid system remains uniform. • Active cooling and PCMs play separate roles in battery thermal management. • Numerical results agree with experiment data and give theoretic insights. - Abstract: Passive thermal management systems using phase change materials (PCMs) provides an effective solution to the overheating of lithium ion batteries. But this study shows heat accumulation in PCMs caused by the inefficient cooling of air natural convection leads to thermal management system failures: The temperature in a battery pack operating continuously outranges the safety limit of 60 °C after two cycles with discharge rate of 1.5 C and 2 C. Here a hybrid system that integrates PCMs with forced air convection is presented. This combined system successfully prevents heat accumulation and maintains the maximum temperature under 50 °C in all cycles. Study on airspeed effects reveals that thermo-physical properties of PCMs dictate the maximum temperature rise and temperature uniformity in the battery pack, while forced air convection plays a critical role in recovering thermal energy storage capacity of PCMs. A numerical study is also carried out and validated with experiment data, which gives theoretic insights on thermo-physical changes in this hybrid battery thermal management system

  17. Thermal stability under air of tungsten–titanium diffusion barrier layer between silica and platinum

    Highlights: •The thermal stability of SiO2/Ti–W/Pt structure under air has been studied. •Oxidation, diffusion and sublimation processes occurred during annealing. •Film surface chemistry and microstructure were correlated with diffusion phenomena. •We proposed WO3 diffusion mechanisms through platinum film. •The WO3 diffusion mechanisms are mainly governed by the layer microstructure. -- Abstract: The present work investigated the thermal stability of tungsten–titanium diffusion barrier layers intercalated between SiO2 substrate and platinum thin film. The resulting structures were annealed under air in the temperature range 400–600 °C for annealing times up to 100 h. Chemical and structural characterizations at different stages of the treatment evidenced several phenomena occurring during annealing under air, especially the complete oxidation of the adhesive layer, the diffusion of tungsten oxide through platinum film at particle boundaries as well as the sublimation process of tungsten oxide. The results of film surface chemistry and microstructure were correlated with diffusion phenomena

  18. A work procedure of utilising PCMs as thermal storage systems based on air-TES systems

    Highlights: • A procedure to design effective thermal energy storage (TES) system. • A guidance for the selection of the working material (PCM) and the heat exchanger development. • Suggestions for heat transfer enhancement techniques for the air-TES system. • Mathematical, computational and experimental methods optimising the air-TES system. - Abstract: The paper seeks to offer a procedure to design an effective short term thermal energy storage (TES) system using phase change materials. The methodology focus on two main aspects: the selection of the working material and the heat exchanger development. The selection of the appropriate PCMs is one of the main keys for any TES therefore their classifications, properties, advantages and disadvantages need to be investigated. Due to the intensive researches using this kind of materials in the recent years, there are a range of commercial PCMs available and supplied by different companies. However, all types of PCM present their specific problems and therefore requirements are defined in order to select the most suitable PCMs. The other main key when designing TES is related to the heat exchanger formed by the PCM and the cold/hot heat sources. For this step, the choice of the appropriate container to encapsulate the PCM and the heat transfer enhancement techniques are analysed. Distinct methodologies such as experimental and numerical study methods and modelling software tools are presented to analyse the thermal energy performance of the system and achieve the optimal design of the TES system

  19. Thermal diffusion: An important aspect in studies of static air columns such as firn air, sand dunes and soil air

    Thermal diffusion induced by temperature gradients is an additional part of diffusional processes besides the ordinary or concentration diffusion. Heavier molecules normally migrate to the colder end of a static column hence leading to a slight separation in composition. Thermal diffusion can be most easily traced by isotopic ratios which are hardly exposed to changes in other processes, such as nitrogen and argon isotope ratios. Since only a limited number of thermal diffusion factors is measured up to now, it is important to have an idea how large they could be to check whether thermal diffusion effects have to be considered in interpreting corresponding isotope or elemental ratios. The Lennard-Jones (13,7) model is quite successful in estimating these factors as seen by comparison between measured and calculated values. However, there are still large uncertainties, particularly in assigning a correct critical temperature to a complex mixture such as air when considering only a ratio of two air components. It seems that the noble gas ratio Ne/Ar would be ideal to separate the gravitational enrichment from thermal diffusion due to a rather high thermal diffusion factor. However, as helium, neon has a high permeability in ice which strongly hampers this advantage. Therefore other noble gas ratios such as Ar/Kr and/or Ar/Xe are favoured for such experiments. For ice core studies the temporal variation of the thermal diffusion fractionation carries a large potential for reconstructing temperature variations over long time periods as well as synchronising gas and ice records with high precision based on very precise estimates of gas-ice age differences. (author)

  20. Experimental analysis of the thermal entrainment factor of air curtains in vertical open display cabinets for different ambient air conditions

    The vertical open refrigerated display cabinets suffer alterations of their thermal performance and energy efficiency due to variations of ambient air conditions. The air curtain provides an aerothermodynamics insulation effect that can be evaluated by the thermal entrainment factor calculation as an engineering approximation or by the calculus of all sensible and latent thermal loads. This study presents the variation of heat transfer rate and thermal entrainment factor obtained through experimental tests carried out for different ambient air conditions, varying air temperature, relative humidity, velocity and its direction relatively to the display cabinet frontal opening. The thermal entrainment factor are analysed and compared with the total sensible and latent heats results for the experimental tests. From an engineering point of view, it is concluded that thermal entrainment factor cannot be used indiscriminately, although its use is suitable to design better cabinet under the same climate class condition.

  1. Photothermal depth profiling: Comparison between genetic algorithms and thermal wave backscattering (abstract)

    Li Voti, R.; Sibilia, C.; Bertolotti, M.

    2003-01-01

    Photothermal depth profiling has been the subject of many papers in the last years. Inverse problems on different kinds of materials have been identified, classified, and solved. A first classification has been done according to the type of depth profile: the physical quantity to be reconstructed is the optical absorption in the problems of type I, the thermal effusivity for type II, and both of them for type III. Another classification may be done depending on the time scale of the pump beam heating (frequency scan, time scan), or on its geometrical symmetry (one- or three-dimensional). In this work we want to discuss two different approaches, the genetic algorithms (GA) [R. Li Voti, C. Melchiorri, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 410 (2001); R. Li Voti, Proceedings, IV Int. Workshop on Advances in Signal Processing for Non-Destructive Evaluation of Materials, Quebec, August 2001] and the thermal wave backscattering (TWBS) [R. Li Voti, G. L. Liakhou, S. Paoloni, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 414 (2001); J. C. Krapez and R. Li Voti, Anal. Sci. 17, 417 (2001)], showing their performances and limits of validity for several kinds of photothermal depth profiling problems: The two approaches are based on different mechanisms and exhibit obviously different features. GA may be implemented on the exact heat diffusion equation as follows: one chromosome is associated to each profile. The genetic evolution of the chromosome allows one to find better and better profiles, eventually converging towards the solution of the inverse problem. The main advantage is that GA may be applied to any arbitrary profile, but several disadvantages exist; for example, the complexity of the algorithm, the slow convergence, and consequently the computer time consumed. On the contrary, TWBS uses a simplified theoretical model of heat diffusion in inhomogeneous materials. According to such a model, the photothermal signal depends linearly on the thermal effusivity

  2. Thermal fatigue behavior of thermal barrier coatings by air plasma spray

    Effects of top coat morphology and thickness on thermal fatigue behavior of Thermal Barrier Coatings (TBC) were investigated in this study. Thermal fatigue tests were conducted on three coating specimens with different top coat morphology and thickness, and then the test data were compared via microstructures, cycles to failure, and fracture surfaces. In the air plasma spray specimens (APS1, APS2), top coat were 200 and 300 μm respectively. The thickness of top coat was about 700 μm in the Perpendicular Cracked Specimen (PCS). Under thermal fatigue condition at 1,100 .deg. C, the cycles to top coat failure of APS1, APS2, and PCS were 350, 560 and 480 cycles, respectively. The cracks were initiated at the interface of top coat and Thermally Grown Oxide (TGO) and propagated into TGO or top coat as the number of thermal fatigue cycles increased. For the PCS specimen, additive cracks were initiated and propagated at the starting points of perpendicular cracks in the top coat. Also, the thickness of TGO and the decrease of aluminium concentration in bond coat do not affect the cycles to failure

  3. Applicability of thermal energy storage recycled ceramics to high temperature and compressed air operating conditions

    Highlights: • ACW ceramics have been successfully tested under ACAES operating conditions. • ACW ceramics have been successfully tested under gas turbine based CSP conditions. • Under 600 °C-30 bars of air, ACW ceramics Cp is slightly lowered by 5%. • Thermal conductivity of ACW ceramics is advantageously enhanced by 30%. - Abstract: Recycled ceramics made of inertized asbestos containing wastes have been submitted to high pressure/temperature cycling tests in the operating range of ACAES and CSP applications. Ten successive cycles between room conditions and 610 °C/30 bars for a cumulated duration of 2500 h lead to a validation of the ability of the material to resist to those constrains. The Wollastonite/Augite initial structure is gradually transformed in a unique Augite containing material. While mechanical parameters and density are unchanged, thermal capacity is reduced by 5% and thermal conductivity increased by 30%. This last result offers an advantageous way to enhance the thermal conductivity of those recycled ceramics, a key parameter to control the charge/discharge power in TES systems

  4. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  5. Calculation of diffusion coefficients in air-metal thermal plasmas

    Cressault, Y; Gleizes, A [Universite de Toulouse, UPS, INPT, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse Cedex 9 (France)

    2010-11-03

    This paper presents the combined diffusion coefficients of metal vapours (silver, copper and iron) in air thermal plasmas for temperatures ranging from 300 to 30 000 K. The theory used to calculate these coefficients is remembered and validated by comparison with the literature values in several cases such as Ar-He, Ar-Cu and N{sub 2}-O{sub 2} mixtures. The results are discussed showing the influences of the metal concentration, of the vapour nature and of the pressure. The results show rather similar behaviour for the three metals. The maximum values of the combined ordinary diffusion coefficient in the evolution with temperature are obtained for temperature around 10 000 K but this peak is shifted to the highest temperatures when the metal proportion increases. Another result shows that the diffusion coefficient decreases when pressure increases.

  6. Modern air protection technologies at thermal power plants (review)

    Roslyakov, P. V.

    2016-07-01

    Realization of the ecologically safe technologies for fuel combustion in the steam boiler furnaces and the effective ways for treatment of flue gases at modern thermal power plants have been analyzed. The administrative and legal measures to stimulate introduction of the technologies for air protection at TPPs have been considered. It has been shown that both the primary intrafurnace measures for nitrogen oxide suppression and the secondary flue gas treatment methods are needed to meet the modern ecological standards. Examples of the environmentally safe methods for flame combustion of gas-oil and solid fuels in the boiler furnaces have been provided. The effective methods and units to treat flue gases from nitrogen and sulfur oxides and flue ash have been considered. It has been demonstrated that realization of the measures for air protection should be accompanied by introduction of the systems for continuous instrumentation control of the composition of combustion products in the gas path of boiler units and for monitoring of atmospheric emissions.

  7. Thermal investigation of lithium-ion battery module with different cell arrangement structures and forced air-cooling strategies

    Highlights: • Three-dimensional CFD model with forced air cooling are developed for battery modules. • Impact of different air cooling strategies on module thermal characteristics are investigated. • Impact of different model structures on module thermal responses are investigated. • Effect of inter-cell spacing on cell thermal characteristics are also studied. • The optimal battery module structure and air cooling strategy is recommended. - Abstract: Thermal management needs to be carefully considered in the lithium-ion battery module design to guarantee the temperature of batteries in operation within a narrow optimal range. This article firstly explores the thermal performance of battery module under different cell arrangement structures, which includes: 1 × 24, 3 × 8 and 5 × 5 arrays rectangular arrangement, 19 cells hexagonal arrangement and 28 cells circular arrangement. In addition, air-cooling strategies are also investigated by installing the fans in the different locations of the battery module to improve the temperature uniformity. Factors that influence the cooling capability of forced air cooling are discussed based on the simulations. The three-dimensional computational fluid dynamics (CFD) method and lumped model of single cell have been applied in the simulation. The temperature distributions of batteries are quantitatively described based on different module patterns, fan locations as well as inter-cell distance, and the conclusions are arrived as follows: when the fan locates on top of the module, the best cooling performance is achieved; the most desired structure with forced air cooling is cubic arrangement concerning the cooling effect and cost, while hexagonal structure is optimal when focus on the space utilization of battery module. Besides, the optimized inter-cell distance in battery module structure has been recommended

  8. An experimental study of thermal comfort at different combinations of air and mean radiant temperature

    Simone, Angela; Olesen, Bjarne W.

    2009-01-01

    It is often discussed if a person prefers a low air temperature (ta) and a high mean radiant temperature (tr), vice-versa or it does not matter as long as the operative temperature is acceptable. One of the hypotheses is that it does not matter for thermal comfort but for perceived air quality, a...... lower air temperature is preferred. This paper presents an experimental study with 30 human subjects exposed to three different combinations of air- and mean radiant temperature with an operative temperature around 23 °C. The subjects gave subjective evaluations of thermal comfort and perceived air...... quality during the experiments. The PMV-index gave a good estimation of thermal sensation vote (TSV) when the air and mean radiant temperature were the same. In the environment with different air- and mean radiant temperatures, a thermal comfort evaluation shows an error up to 1 scale unit on the 7-point...

  9. Experimental study on the thermal performance and pressure drop of a solar air collector based on flat micro-heat pipe arrays

    Highlights: • A new type of solar air collector by using flat micro-heat pipe arrays is proposed. • Thermal efficiency rates in summer and winter are approximately 73% and 56%. • The pressure loss is below 25 Pa when the volume flow rate is less than 201.6 m3/h. - Abstract: A new solar air collector that combines the use of flat micro-heat pipe arrays (FMHPA) and evacuated tube is developed and investigated. Using FMHPA as the central transporting component in a solar air collector is an effective approach to improve the collector’s thermal properties and reduce its pressure drop. The thermal properties and pressure drop of the FMHPA solar air collector are analyzed in detail. The main objective of this paper is to report test results of the FMHPA solar air collectors which includes the effects of different seasons and airflow rates on the thermal efficiency and the pressure drop of the air collector. In summer, the thermal efficiency of the collector reaches 73% under stable operation. In the testing airflow range condition, the pressure drop is less than 25 Pa when the flow rate is below 201.6 m3/h. The relative uncertainty of thermal efficiency is approximately 7.73%

  10. Non-thermal plasma for air and water remediation.

    Hashim, Siti Aiasah; Samsudin, Farah Nadia Dayana Binti; Wong, Chiow San; Abu Bakar, Khomsaton; Yap, Seong Ling; Mohd Zin, Mohd Faiz

    2016-09-01

    A modular typed dielectric barrier discharge (DBD) device is designed and tested for air and water remediation. The module is made of a number of DBD tubes that can be arranged in series or parallel. Each of the DBD tubes comprises inner electrode enclosed with dielectric barrier and arranged as such to provide a gap for the passage of gases. Non-thermal plasma generated in the gap effectively creates gaseous chemical reactions. Its efficacy in the remediation of gas stream containing high NOx, similar to diesel emission and wastewater containing latex, are presented. A six tubes DBD module has successfully removed more than 80% of nitric oxide from the gas stream. In another arrangement, oxygen was fed into a two tubes DBD to generate ozone for treatment of wastewater. Samples of wastewater were collected from a treatment pond of a rubber vulcanization pilot plant. The water pollution load was evaluated by the chemical oxygen demand (COD) and biological oxygen demand (BOD5) values. Preliminary results showed some improvement (about 13%) on the COD after treatment and at the same time had increased the BOD5 by 42%. This results in higher BOD5/COD ratio after ozonation which indicate better biodegradability of the wastewater. PMID:27056469

  11. Analysis of air flow distribution and thermal comfort in a hybrid electric vehicle

    Ningbai, Ningbai

    2014-01-01

    Energy efficiency in Hybrid Electric Vehicles (HEV) affects the vehicle mileage and battery durability. Air conditioning is the most energy consuming system after the electric motor in HEVs. Air flow distribution and thermal comfort in an HEV is studied and simulations are performed to investigate the optimum air distribution pattern for providing thermal comfort while maintaining energy efficiency. To acquire a preliminary understanding of the problem, an analytical model is developed for ai...

  12. The Thermal Plume above a Standing Human Body Exposed to Different Air Distribution Strategies

    Liu, Li; Nielsen, Peter V.; Li, Yuguo;

    2009-01-01

    This study compares the impact of air distribution on the thermal plume above a human body in indoor environment. Three sets of measurements are conducted in a full-scale test room with different ventilation conditions. One breathing thermal manikin standing in the room is used to simulate the...... human body. Long-time average air velocity profiles at locations closely above the manikin are taken to identify the wandering thermal plume....

  13. Effective Ventilation Parameters and Thermal Comfort Study of Air-conditioned Offices

    Roonak Daghigh

    2009-01-01

    Full Text Available The study presents objective and subjective studies of thermal comfort levels and ventilation characteristics of two air-conditioned postgraduate study offices. The observations were performed at the offices of Department of Electrical and Electronic Engineering, in University Putra Malaysia. Thermal comfort variables were measured while the students answered a survey on their sensation of the indoor climate. Concurrently, tracer gas analysis, based on concentration decay method, is employed to determine air exchange rate, age of air and air exchange effectiveness. During the air conditioner is working, the study offices had not conditions within the comfort zone, of ASHRAE standard 55 causing occupants to report cold thermal sensations and the objective data analysis showed that the offices were uncomfortable. The thermal neutralities were significantly higher that proposed by ASHRAE Standard 55:1992. The monitored air exchange rates are indicated that the provisions of outside air for ventilation based on design occupancy are adequate for these two study offices. In addition, questionnaires were completed by the students in order to provide a subjective assessment of thermal comfort and indoor air quality. Finally, the outcomes of over 30 surveys for each office responses to the thermal comfort questions are presented and discussed.

  14. Active Participation of Air Conditioners in Power System Frequency Control Considering Users’ Thermal Comfort

    Rongxiang Zhang; Xiaodong Chu; Wen Zhang; Yutian Liu

    2015-01-01

    Air conditioners have great potential to participate in power system frequency control. This paper proposes a control strategy to facilitate the active participation of air conditioners. For each air conditioner, a decentralized control law is designed to adjust its temperature set point in response to the system frequency deviation. The decentralized control law accounts for the user’s thermal comfort that is evaluated by a fuzzy algorithm. The aggregation of air conditioners’ response is c...

  15. Air-borne noise of thermal module and system for notebook personal computers:experimental study

    2008-01-01

    Thermal performance is the most important issue to be considered when a thermal module is designed for a notebook personal computer (PC).Because the fan causes air-borne noise and affects the user's comfort,the acoustic characteristics of the module attract more attention.Experiments were conducted to study the noise sources,the noise characteristic and the main factors influencing the noise level.The difference between the air-borne noise of the thermal module and the whole computer system was analyzed and its propagating characteristics were derived.The influence of I/O ports on the air-borne noise was also studied experimentally.

  16. Measurement and prediction of indoor air quality using a breathing thermal manikin

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2007-01-01

    The analyses performed in this paper reveal that a breathing thermal manikin with realistic simulation of respiration including breathing cycle, pulmonary ventilation rate, frequency and breathing mode, gas concentration, humidity and temperature of exhaled air and human body shape and surface...... temperature is sensitive enough to perform reliable measurement of characteristics of air as inhaled by occupants. The temperature, humidity, and pollution concentration in the inhaled air can be measured accurately with a thermal manikin without breathing simulation if they are measured at the upper lip...... at a distance of breathing, especially of exhalation, is needed for studying the transport of exhaled air between occupants. A method...

  17. Test Method for Determination of Thermal Shock resistance(Air Quenching)

    LIYong-gang; ZHANGYong-fang; 等

    1995-01-01

    On the basis of the theory of thermal shock resistance in the science of materials and the test method of air quenching which is generally rec-ognized internationally,especially in Europe,the present test methods for determination of thermal shock resistance in China have been analysed,Experiment study on thermal shock resis-tance of silica and basic refractory products has been conducted,and a new test method of thermal shock resistance-air quenching method has been put forward.

  18. Thermal Gradient Behavior of TBCs Subjected to a Laser Gradient Test Rig: Simulating an Air-to-Air Combat Flight

    Lima, Rogerio S.; Marple, Basil R.; Marcoux, P.

    2016-01-01

    A computer-controlled laser test rig (using a CO2 laser) offers an interesting alternative to traditional flame-based thermal gradient rigs in evaluating thermal barrier coatings (TBCs). The temperature gradient between the top and back surfaces of a TBC system can be controlled based on the laser power and a forced air back-face cooling system, enabling the temperature history of complete aircraft missions to be simulated. An air plasma spray-deposited TBC was tested and, based on experimental data available in the literature, the temperature gradients across the TBC system (ZrO2-Y2O3 YSZ top coat/CoNiCrAlY bond coat/Inconel 625 substrate) and their respective frequencies during air-to-air combat missions of fighter jets were replicated. The missions included (i) idle/taxi on the runway, (ii) take-off and climbing, (iii) cruise trajectory to rendezvous zone, (iv) air-to-air combat maneuvering, (v) cruise trajectory back to runway, and (vi) idle/taxi after landing. The results show that the TBC thermal gradient experimental data in turbine engines can be replicated in the laser gradient rig, leading to an important tool to better engineer TBCs.

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

    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)

  20. Seat headrest-incorporated personalized ventilation: Thermal comfort and inhaled air quality

    Melikov, Arsen Krikor; Ivanova, T.; Stefanova, G.

    2012-01-01

    The performance of personalized ventilation with seat headrest-mounted air supply terminal devices (ATD), named seat headrest personalized ventilation (SHPV), was studied. Physical measurements using a breathing thermal manikin were taken to identify its ability to provide clean air to inhalation...... occupants are seated most of the time, e.g. theatres, vehicle compartments, etc. © 2011 ....

  1. DESIGN OF SECONDARY AIR SYSTEM AND THERMAL MODELS FOR TRIPLE SPOOL JET ENGINES

    Caty, Fabien

    2012-01-01

    This master thesis deals with the understanding of the secondary air system of athree spool turbofan. The main purpose is the creation of secondary air systemand thermal models to evaluate the behavior of this kind of engine architectureand estimate the pros and cons in comparison with a typical two spool turbofan. Afinite element model of the secondary air system of the engine has been designedbased on the experience of typical jet engines manufactured by Snecma. Theinner thermodynamic patte...

  2. Thermal behaviour of a solar air heater with a compound parabolic concentrator

    A mathematical model for computing the thermal performance of an air heater with a truncated compound parabolic concentrator having a flat one-sided absorber is presented. A computed code that employs an iterative solution procedure is constructed to solve the governing energy equations and to estimate the performance parameters of the collector. The effects of the air mass flow rate, the wind speed and the collector length on the thermal performance of the present air heater are investigated. Prediction for the performance of the solar heater also exhibits reasonable agreement with experimental data with an average error of 7%. (author)

  3. Conversion of carbon disulfide in air by non-thermal plasma

    Highlights: • The behavior of NTP for CS2 conversion in air was investigated. • CS2 conversion increase with the increase of specific input energy. • Short-living species are more important in CS2 conversion than long-living species. • The main gaseous products of CS2 conversion are CO, CO2, OCS, SO2, SO3 and H2SO4. • YCO2 and YCO increase, YSO3+H2SO4 remains constant, and YSO2 and YOCS follow bell curves as SIE increases. -- Abstract: Carbon disulfide (CS2), a typical odorous organic sulfur compound, has adverse effects on human health and is a potential threat to the environment. In the present study, CS2 conversion in air by non-thermal plasma (NTP) was systematically investigated using a link tooth wheel-cylinder plasma reactor energized by a DC power supply. The results show that corona discharge is effective in removing CS2. The CS2 conversion increases with the increase of specific input energy (SIE). Both short-living (e.g. ·O, ·OH radicals) and long-living species contribute to the CS2 conversion, but the short-living species play a more important role. Both gaseous and solid products are formed during the conversion of CS2. Gaseous products mainly include CO, CO2, OCS, SO2, SO3 and H2SO4. The yields of CO and CO2 increase, the yields of OCS and SO2 follow bell curves while the sum yield of SO3 and H2SO4 remains constant as SIE increases. The solid products, consisting of CO32−, SO42− and possible polymeric sulfur, deposit on the inner wall and electrodes of the plasma reactor

  4. Thermal Comfort Evaluation of a Heat Pump System using Induced-air Supply Unit

    Ling, Jiazhen; Xu, Jian; Aute, Vikrant; Radermacher, Reinhard

    2014-01-01

    Traditional heat pump systems supply conditioned air to space at certain temperatures such as, in summer, about 16°C. When the supply-air temperature drops too low, most occupants tend to feel uncomfortable. On the other hand, a certain amount of dehumidification has to be carried out and sometimes, the velocity of supply-air has to be high which in turn creates a draught. This paper introduces a new air supply method to reduce fan power consumption as well as to improve thermal comfort of oc...

  5. Effect of Air Velocity on Thermal Comfort in an Automobile Cabin

    Mehmet Özgün Korukçu

    2011-06-01

    Full Text Available The aim of this study is to evaluate the effect of air velocity on thermal comfort during heating period in an automobile cabin with experiments. In the evaluation of comfort in automobiles, in general temperature, humidity, air velocity and radiant temperature measurements are taken. In the study, ambient temperature, relative humidity, mean radiant temperature and mean skin temperature of the driver inside the automobile cabin during heating for different vent air mass flow rates were measured in a parked car. Subjective survey was performed during the experiments to the driver. The results for different vent air mass flow rate values were compared with answers taken from the subject and discussed.

  6. Obtaining the Thermal Structure of Lakes from the Air

    Michaella Chung

    2015-11-01

    Full Text Available The significance of thermal heterogeneities in small surface water bodies as drivers of mixing and for habitat provision is increasingly recognized, yet obtaining three-dimensionally-resolved observations of the thermal structure of lakes and rivers remains challenging. Remote observations of water temperature from aerial platforms are attractive: such platforms do not require shoreline access; they can be quickly and easily deployed and redeployed to facilitate repeated sampling and can rapidly move between target locations, allowing multiple measurements to be made during a single flight. However, they are also subject to well-known limitations, including payload, operability and a tradeoff between the extent and density over which measurements can be made within restricted flight times. This paper introduces a novel aerial thermal sensing platform that lowers a temperature sensor into the water to record temperature measurements throughout a shallow water column and presents results from initial field experiments comparing \\emph{in situ} temperature observations to those made from the UAS platform. These experiments show that with minor improvements, UASs have the potential to enable high-resolution 3D thermal mapping of a \\(\\sim\\1-ha lake in 2–3 flights (\\textit{circa} 2 h, sufficient to resolve diurnal variations. This paper identifies operational constraints and key areas for further development, including the need for the integration of a faster temperature sensor with the aerial vehicle and better control of the sensor depth, especially when near the water surface.

  7. Integration of thermal insulation coating and moving-air-cavity in a cool roof system for attic temperature reduction

    Highlights: • A novel integrated cool roof system for attic temperature reduction is introduced. • 13 °C temperature reduction achieved due to its efficient heat transfer mechanism. • Aluminium tube cavity of the roof is able to reduce the attic temperature. • This positive result is due to its efficient heat reflection and hot air rejection. • Thermal insulation coating incorporates the usage of eggshell waste as bio-filler. - Abstract: Cool roof systems play a significant role in enhancing the comfort level of occupants by reducing the attic temperature of the building. Heat transmission through the roof can be reduced by applying thermal insulation coating (TIC) on the roof and/or installing insulation under the roof of the attic. This paper focuses on a TIC integrated with a series of aluminium tubes that are installed on the underside of the metal roof. In this study, the recycled aluminium cans were arranged into tubes that act as a moving-air-cavity (MAC). The TIC was formulated using titanium dioxide pigment with chicken eggshell (CES) waste as bio-filler bound together by a polyurethane resin binder. The thermal conductivity of the thermal insulation paint was measured using KD2 Pro Thermal Properties Analyzer. Four types of cool roof systems were designed and the performances were evaluated. The experimental works were carried out indoors by using halogen light bulbs followed by comparison of the roof and attic temperatures. The temperature of the surrounding air during testing was approximately 27.5 °C. The cool roof that incorporated both TIC and MAC with opened attic inlet showed a significant improvement with a reduction of up to 13 °C (from 42.4 °C to 29.6 °C) in the attic temperature compared to the conventional roof system. The significant difference in the results is due to the low thermal conductivity of the thermal insulation paint (0.107 W/mK) as well as the usage of aluminium tubes in the roof cavity that was able to transfer

  8. Human requirements to the indoor air quality and the thermal environment

    Fanger, P. Ole

    Perceived air quality, general thermal sensation of the occupants and risk of draft, aspects which human comfort in a space depends upon, are reviewed separately based on European Guidelines for Ventilation Requirements in Buildings and on a modified ISO (International Standards Organization) standard 7730 on thermal comfort. The perceived air quality is expressed in decipol or percentage of dissatisfied occupants. The general thermal sensation is expressed by the PMV/PPD indices. The perception of draft is expressed by the model of draft risk. Indoor air quality is mediocre and causes complaints in many buildings. The reason for this is often hidden pollution sources in the building, hitherto ignored in previous ventilation standards. To determine the required ventilation, a method is used in the European Guidelines. The new Guidelines acknowledge all pollution sources in the building, expressed in olfs. The method is based on the desired air quality in the space, the available quality of the outdoor air, the ventilation effectiveness and on the total pollution load in the space. The model of draft risk predicts the percentage of occupants feeling draft as a function of the mean air velocity, the turbulence intensity and the air temperature.

  9. Solar thermal drying of apricots: Effect of spectrally-selective cabinet materials on drying rate and quality metrics (abstract)

    Solar thermal (ST) drying is currently not in widespread commercial use due to concerns about slow drying rates and poor product quality. ST dryer cabinets could be constructed from spectrally-selective materials (materials which transmit only certain sunlight wavelength bands), but these types of ...

  10. Microstructure and thermal properties of nanostructured lanthana-doped yttria-stabilized zirconia thermal barrier coatings by air plasma spraying

    Nanostructured lanthana-doped yttria-stabilized zirconia thermal barrier coatings were developed using the air plasma spraying technique. Scanning and transmission electron microscopy studies revealed that the coatings are characterized by a bimodal microstructure consisting of melted zones, nano-zones, splats, nano-pores and micro-cracks, which are typical features of nanostructured plasma-sprayed coatings. These coatings are tetragonal in phase, with a grain size of 30–60 nm. The thermal conductivity achieved by these coatings is lower than that of nanostructured and traditional yttria-stabilized zirconia coatings.

  11. Parametric study of a solar air heater with and without thermal storage for solar drying applications

    Aboul-Enein, S.; El-Sebaii, A.A.; Ramadan, M.R.I.; El-Gohary, H.G. [Tanta Univ., Physics Dept., Tanta (Egypt)

    2000-12-01

    A transient analytical model is presented for a flat-plate solar air heater with and without thermal storage. The flowing air temperature is assumed to vary with time and space coordinates. Analytical expressions are obtained for various temperatures of the air heater elements as well as for the temperature of the storage material. The performance of the air heater is investigated by computer simulation using the climatic conditions of Tanta (Lat. 30deg 47' N, Egypt). Effects of design parameters of the air heater such as length (L), width (b), gap spacing between the absorber plate and glass cover (d{sub f}), mass flow rate (m) and thickness and type of the storage material (sand, granite and water) on the outlet and average temperatures of the flowing air are studied. It is found that as L and b increase the average temperatures of flowing air (T{sub fav}) increases up to typical values for these parameters. Typical values for L and b are obtained as 3 and 2 m, respectively. The outlet temperature (T{sub fo}) of flowing air is found to decrease with increasing gap spacing and mass flow rate of air. Improvements in the heater performance with storage have been achieved at the optimum thickness (0.12 m) of the storage material. Therefore, the air heater can be used as a heat source for drying agricultural products and the drying process will continue during night, instead of re-absorption of moisture from the surrounding air. Comparisons between experimental and theoretical results indicated that the proposed mathematical model can be used for estimating the thermal performance of flat-plate solar air heaters with reasonable accuracy. (Author)

  12. Analysis of thermal and electrical performance of a hybrid (PV/T) air based solar collector for Iraq

    Highlights: ► An improved model is developed for single pass glazed PV/T collector. ► We examined the influence of different parameters. ► A summer day has better heating with lower overall efficiency compared with a winter day. -- Abstract: The electrical and thermal performance of a typical single pass hybrid photovoltaic/thermal (PV/T) air collector is modeled, simulated and analyzed for two selected case studies in Iraq. An improved mathematical thermo-electrical model is derived in terms of design, operating and climatic parameters of the hybrid solar collector to evaluate its important characteristics: collector flow and heat removal factors, PV maximum power point and its temperature coefficient, and overall power and efficiency. Unlike previous PV/T thermal models, the present model is obtained with some additions and corrections in radiation and convection heat coefficients for the top loss and for the air duct with more applicable sky temperature correlation. The well-known 5-parameter electrical model of PV module is solved using improved boundary conditions and translation equations for better convergence and accuracy. The voltage temperature coefficient of the PV module is included in the boundary conditions for convergence stability. The module parameters are taken to be dependent on solar radiation and PV cell temperature for improved accuracy. A Matlab computer simulation program is developed to solve the thermo-electrical model. The developed model is verified with previously published experimental results and theoretical simulations; it is proved to be most accurate in respect to percentage errors and correlation coefficients. Different parameters of the PV/T collector such as cell and air temperatures, thermal gain, PV current and voltage, and fill factor have been investigated. The results identified the effects of most important operating conditions such as sky, inlet and cell temperatures, air flow rate and incident solar radiation on

  13. Partitioned airs at microscale and nanoscale: thermal diffusivity in ultrahigh porosity solids of nanocellulose.

    Sakai, Koh; Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

    2016-01-01

    High porosity solids, such as plastic foams and aerogels, are thermally insulating. Their insulation performance strongly depends on their pore structure, which dictates the heat transfer process in the material. Understanding such a relationship is essential to realizing highly efficient thermal insulators. Herein, we compare the heat transfer properties of foams and aerogels that have very high porosities (97.3-99.7%) and an identical composition (nanocellulose). The foams feature rather closed, microscale pores formed with a thin film-like solid phase, whereas the aerogels feature nanoscale open pores formed with a nanofibrous network-like solid skeleton. Unlike the aerogel samples, the thermal diffusivity of the foam decreases considerably with a slight increase in the solid fraction. The results indicate that for suppressing the thermal diffusion of air within high porosity solids, creating microscale spaces with distinct partitions is more effective than directly blocking the free path of air molecules at the nanoscale. PMID:26830144

  14. Occupant Time Period of Thermal Adaption to Change of Outdoor Air Temperature in Naturally Ventilated Buildings

    liu, weiwei; Wargocki, Pawel; Xiong, Jing

    2014-01-01

    The present work proposed a method to determine time period of thermal adaption of occupants in naturally ventilated building, based on the relationship between their neutral temperatures and running mean outdoor air temperature. Based on the data of the field investigation, the subjects’ time pe...... with the value of the subjects in this study. The comparison shows that the occupants in China had a shorter time period of thermal adaption than European occupants, which means that Chinese occupants can adapt to a new outdoor climate condition faster....... period of thermal adaption was obtained with the proposed method. The result revealed that the subjects needed to take 4.25 days to fully adapt to a step-change in outdoor air temperature. The time period of thermal adaption for the occupants in five European countries was also calculated and compared...

  15. Partitioned airs at microscale and nanoscale: thermal diffusivity in ultrahigh porosity solids of nanocellulose

    Sakai, Koh; Kobayashi, Yuri; Saito, Tsuguyuki; Isogai, Akira

    2016-02-01

    High porosity solids, such as plastic foams and aerogels, are thermally insulating. Their insulation performance strongly depends on their pore structure, which dictates the heat transfer process in the material. Understanding such a relationship is essential to realizing highly efficient thermal insulators. Herein, we compare the heat transfer properties of foams and aerogels that have very high porosities (97.3-99.7%) and an identical composition (nanocellulose). The foams feature rather closed, microscale pores formed with a thin film-like solid phase, whereas the aerogels feature nanoscale open pores formed with a nanofibrous network-like solid skeleton. Unlike the aerogel samples, the thermal diffusivity of the foam decreases considerably with a slight increase in the solid fraction. The results indicate that for suppressing the thermal diffusion of air within high porosity solids, creating microscale spaces with distinct partitions is more effective than directly blocking the free path of air molecules at the nanoscale.

  16. Study on the Thermal Effects and Air Quality Improvement of Green Roof

    Heng Luo; Ning Wang; Jianping Chen; Xiaoyan Ye; Yun-Fei Sun

    2015-01-01

    Heat island phenomenon and air quality deterioration issues are two major problems that have occurred during the process of urbanization, especially in developing countries. A number of measures have been proposed, among which roof greening is considered as a promising one due to its outstanding performance in thermal effects as well as air quality improvement. A self-maintenance system, termed the Green Roof Manager (GRM), which comprises the irrigation and shadowing subsystems, is proposed...

  17. Through thickness air permeability and thermal conductivity analysis for textile materials

    Saldaeva, Elena

    2010-01-01

    Woven fabrics have found enormous application in our daily life and in industry because of their flexibility, strength and permeability. The aim of this work was to create a general model for through thickness air permeability and thermal conductivity for different types of textile fabrics because of their applications in industries and everyday life. An analytical model to predict through thickness air permeability was developed. The objective was to create a model which will take into con...

  18. BitWhisper: Covert Signaling Channel between Air-Gapped Computers using Thermal Manipulations

    Guri, Mordechai; Monitz, Matan; Mirski, Yisroel; Elovici, Yuval

    2015-01-01

    It has been assumed that the physical separation (air-gap) of computers provides a reliable level of security, such that should two adjacent computers become compromised, the covert exchange of data between them would be impossible. In this paper, we demonstrate BitWhisper, a method of bridging the air-gap between adjacent compromised computers by using their heat emissions and built-in thermal sensors to create a covert communication channel. Our method is unique in two respects: it supports...

  19. Impact Analysis of Air Pollutant Emission Policies on Thermal Coal Supply Chain Enterprises in China

    Xiaopeng Guo; Xiaodan Guo; Jiahai Yuan

    2014-01-01

    Spurred by the increasingly serious air pollution problem, the Chinese government has launched a series of policies to put forward specific measures of power structure adjustment and the control objectives of air pollution and coal consumption. Other policies pointed out that the coal resources regional blockades will be broken by improving transportation networks and constructing new logistics nodes. Thermal power takes the largest part of China’s total installed power generation capacity,...

  20. Characterization of Air-Based Photovoltaic Thermal Panels with Bifacial Solar Cells

    Ooshaksaraei, P.; K. Sopian; Zulkifli, R.; Saleem H. Zaidi

    2013-01-01

    Photovoltaic (PV) panels account for a majority of the cost of photovoltaic thermal (PVT) panels. Bifacial silicon solar panels are attractive for PVT panels because of their potential to enhance electrical power generation from the same silicon wafer compared with conventional monofacial solar panels. This paper examines the performance of air-based bifacial PVT panels with regard to the first and second laws of thermodynamics. Four air-based bifacial PVT panels were designed. The maximum ef...

  1. Performances of air plasma sprayed thermal barrier coatings for industrial gas turbines

    Seraffon, Maud

    2012-01-01

    Future industrial gas turbines will be required to operate at higher temperatures to increase operating efficiencies and will be subjected to more frequent thermal cycles. The temperatures that the substrates of components exposed in the harshest environments experience can be reduced using air-cooling systems coupled with ceramic thermal barrier coatings (TBCs); however, few studies have been carried out at the substrate temperatures encountered in industrial gas turbines (e.g...

  2. Experimental investigation of thermal comfort and air quality in an automobile cabin during the cooling period

    Kilic, M.; Akyol, S. M.

    2012-08-01

    The air quality and thermal comfort strongly influenced by the heat and mass transfer take place together in an automobile cabin. In this study, it is aimed to investigate and assess the effects of air intake settings (recirculation and fresh air) on the thermal comfort, air quality satisfaction and energy usage during the cooling period of an automobile cabin. For this purpose, measurements (temperature, air velocity, CO2) were performed at various locations inside the cabin. Furthermore, whole body and local responses of the human subjects were noted while skin temperatures were measured. A mathematical model was arranged in order to estimate CO2 concentration and energy usage inside the vehicle cabin and verified with experimental data. It is shown that CO2 level inside of the cabin can be greater than the threshold value recommended for the driving safety if two and more occupants exist in the car. It is also shown that an advanced climate control system may satisfy the requirements for the air quality and thermal comfort as well as to reduce the energy usage for the cooling of a vehicle cabin.

  3. Thermal decomposition of rare earth pyromucates in air atmosphere

    The conditions of thermal decomposition of Y, La and lanthanide (from Ce(III) to Lu) pyromucates were studied. On heating these complexes decompose in various ways: La, Pr, Nd and Sm pyromucates in four stages, Ce, Eu, Gd, Dy, Ho and Er in three stages, and Tm, Yb, Lu and Y in two stages, the oxides are formed finally. The hydrated complexes (from La to Er) lose crystallization water to form anhydrous salts. The anhydrous complexes of La, Pr, Nd and Sm decompose to oxides through the intermediate formation of unstable oxypyromucates and Lnsub(2)Osub(2)COsub(3), whereas the anhydrous complexes of Ce(III), Eu, GdDy, Ho, Er, Tm, Yb and Lu decompose to the oxides through the intermediate formation of oxypyromucates. The temperatures of dehydration and oxide formation change periodically with increasing atomic number in the lanthanide series. (author)

  4. Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage

    Highlights: • The paper presents a thermodynamic analysis of A-CAES using packed bed regenerators. • The packed beds are used to store the compression heat. • A numerical model is developed, validated and used to simulate system operation. • The simulated efficiencies are between 70.5% and 71.1% for continuous operation. • Heat build-up in the beds reduces continuous cycle efficiency slightly. - Abstract: The majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge–storage–discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation

  5. Micro-fabrication and thermal characteristics of a thermal mass air flow sensor for real-time applications

    A thermal Mass Air Flow Sensor (MAFS), which consists of a micro-heater and thermo-resistive sensors on the silicon-nitride (Si3N4) thin membrane structure, is micro-fabricated by MEMS processes. Two thermo-resistive temperature sensors are located at 100μm upstream and downstream from the micro-heater respectively. The thermal characteristics are measured to find the best measurement indicator. The micro-heater is operated under constant power condition, and four flow indicators are investigated. The normalized temperature indicator shows good physical meaning and is easy to use in practices. It is found that the configurations and heating power of thermal-resistive elements are the dominant factors to determine the range of the flow measurement in the MAFS with higher sensitivity and accuracy

  6. Measurement of Indoor Air Quality by Means of a Breathing Thermal Manikin

    Brohus, Henrik

    When a person is located in a contaminant field with significant gradients the contaminant distribution is modified locally due to the entrainment and transport of room air in the human convective boundary layer as well as due to the effect of the person acting as an obstacle to the flow field, etc....... The local modification of the concentration distribution may affect the personal exposure significantly and, thus, the indoor air quality actually experienced. In this paper measurements of indoor air quality by means of a Breathing Thermal Manikin (BTM) are presented....

  7. Thermal environment and air quality in office with personalized ventilation combined with chilled ceiling

    Lipczynska, Aleksandra; Kaczmarczyk, Jan; Melikov, Arsen Krikor

    2015-01-01

    The thermal environment and air quality conditions provided with combined system of chilled ceiling and personalized ventilation (PV) were studied in a simulated office room for two occupants. The proposed system was compared with total volume HVAC solutions used today, namely mixing ventilation...... and chilled ceiling combined with mixing ventilation. The objective of the study was to evaluate whether PV can be the only ventilation system in the rooms equipped with chilled ceiling. The room air temperature was 26°C in cases with traditional systems and 28°C when PV was used. PV supplied air with...

  8. Air-ground temperature coupling: analysis by means of Thermal Orbits

    Čermák, Vladimír; Bodri, L.

    2016-01-01

    Roč. 6, č. 1 (2016), s. 112-122. ISSN 2160-0414 R&D Projects: GA ČR(CZ) GAP210/11/0183; GA MŠk(CZ) LG13040 Institutional support: RVO:67985530 Keywords : Thermal Orbits * temperature monitoring * air temperature vs ground temperature Subject RIV: DG - Athmosphere Sciences, Meteorology

  9. Field study of thermal comfort and indoor air quality in gymnasium

    谢慧; 甘晓爱; 马飞

    2009-01-01

    To analyze the thermal comfort and indoor air quality (IAQ) in a medium-sized mechanically ventilated gymnasium in Beijing,a field study was carried out. PHOENICS,one of the CFD software,was chosen to simulate the distribution of the indicators of indoor air in the gymnasium to check the air-conditioning parameters reasonable or not. And there was a questionnaire for audiences and staff about the acceptance and satisfaction of the thermal comfort,simultaneously,some environmental parameters were monitored. Then an experiment was carried out in gymnasium with the plate sedimentation to the biological aerosol in the air. Finally,the thermal comfort and IAQ in the gymnasium were assessed based on the results of above questionnaire survey and measurements. The results show that most parameters of the environmental are within the standard limits of thermal comfort and IAQ in the monitored period,and the biological contaminants initially come from human beings. The main species in the gymnasium are streptobacillus,coccus,cladosporium,penicillium and neurospora.

  10. Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

    Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

    2008-01-01

    NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

  11. Sensitivity analysis of thermal performances of flat plate solar air heaters

    Njomo, Donatien [University of Yaounde I, Heat Transfer Laboratory, PO Box 812, Yaounde (Cameroon); Daguenet, Michel [Universite de Perpignan, Laboratoire de Thermodynamique et Energetique, Perpignan (France)

    2006-10-15

    Sensitivity analysis is a mathematical tool, first developed for optimization methods, which aim is to characterize a system response through the variations of its output parameters following modifications imposed on the input parameters of the system. Such an analysis may quickly become laborious when the thermal model under consideration is complex or the number of input parameters is high. In this paper, we develop a mathematical model to analyse the heat exchanges in four different types of solar air collectors. When building this thermal model we show that for each collector, at quasi-steady state, the energy balance equations of the components of the collector cascade into a single first-order non-linear differential equation that is able to predict the thermal behaviour of the collector. Our heat transfer model clearly demonstrates the existence of an important dimensionless parameter, referred to as the thermal performance factor of the collector, that compares the useful thermal energy which can be extracted from the heater to the overall thermal losses of that collector for a given set of input parameters. A sensitivity analysis of our thermal model has been performed for the most significant input parameters such as the incident solar irradiation, the inlet fluid temperature, the air mass flow rate, the depth of the fluid channel, the number and nature of the transparent covers in order to measure the impact of each of these parameters on our model. An important result which can be drawn from this study is that the heat transfer model developed is robust enough to be used for thermal design studies of most known flat plate solar air heaters, but also of flat plate solar water collectors and linear solar concentrators. (orig.)

  12. The Thermal Performance and Air Leakage Characteristics of Six Log Homes in Idaho.

    Roos, Carolyn; Eklund, Ken; Baylon, David

    1993-08-01

    The thermal performance and air leakage characteristics of four electrically heated log houses located in Idaho are summarized. The air leakage and construction characteristics of two additional log homes are also examined. The energy consumption of the four homes was submetered at weekly reporting intervals for up to 16 months. Blower door tests and site audits were performed. In addition, conditions at two of these homes, including heat flux through the log walls, indoor and outdoor temperatures, solar flux and envelope tightness, were measured in detail over several days during winter conditions. The energy use and thermal performance of these two homes were then modeled using SUNCODE-PC, an hourly thermal simulation program employing a finite difference technique.

  13. Technical meeting on heat transfer, thermal-hydraulics and system design for supercritical pressure water cooled reactors. Book of abstracts

    There is high interest internationally in both developing and industrialized countries in the design of innovative supercritical water cooled reactors (SCWRs). This interest arises from the high thermal efficiencies (44-45%) and improved economic competitiveness promised by this concept, which utilizes and builds upon the recent developments of highly efficient fossil power plants. The SCWR is one of the six concepts included in the Generation-IV International Forum (GIF). In support of Member States' efforts in the area of SCWRs, the IAEA started in 2008 a Coordinated Research Project (CRP) on 'Heat Transfer Behaviour and Thermo-hydraulics Code Testing for SCWRs'. The two key objectives of this CRP are: 1) To establish accurate databases for heat transfer, pressure drop, blowdown, natural circulation, and stability for conditions relevant to supercritical pressure fluids, and 2) To test analysis methods for SCWR thermohydraulic behaviour, and identify code development needs. Annual Research Coordination Meetings take place under the framework of this CRP once a year to assess the progress of the project. These meetings are mainly focused on programmatic issues associated with the project and very little time is available for discussion on details and specific technical areas. This is why during the 2nd Research Coordination Meeting for this CRP held in Vienna in August 24-27, 2009, Member States expressed an interest in organizing a technical meeting in which specialists in the areas of heat transfer and thermal-hydraulics, thermodynamics and systems design for supercritical water cooled reactors would have the opportunity of participating in extended technical discussions on the details associated to the science and engineering of supercritical water cooled reactor concepts. The University of Pisa kindly offered to host such a technical meeting. The purpose of the meeting was to provide a platform for detailed presentations and technical discussions leading, to

  14. Abstract algebra

    Deskins, W E

    1996-01-01

    This excellent textbook provides undergraduates with an accessible introduction to the basic concepts of abstract algebra and to the analysis of abstract algebraic systems. These systems, which consist of sets of elements, operations, and relations among the elements, and prescriptive axioms, are abstractions and generalizations of various models which evolved from efforts to explain or discuss physical phenomena.In Chapter 1, the author discusses the essential ingredients of a mathematical system, and in the next four chapters covers the basic number systems, decompositions of integers, diop

  15. NOx emission and thermal efficiency of a 300 MWe utility boiler retrofitted by air staging

    Li, S.; Xu, T.M.; Hui, S.; Wei, X.L. [Chinese Academy of Sciences, Beijing (China). Inst. of Mechanics

    2009-09-15

    Full-scale experiments were performed on a 300 MWe utility boiler retrofitted with air staging. In order to improve boiler thermal efficiency and to reduce NOx emission, the influencing factors including the overall excessive air ratio, the secondary air distribution pattern, the damper openings of CCOFA and SOFA, and pulverized coal fineness were investigated. Through comprehensive combustion adjustment, NOx emission decreased 182 ppm (NOx reduction efficiency was 44%), and boiler heat efficiency merely decreased 0.21%. After combustion improvement, high efficiency and low NOx emission was achieved in the utility coal-fired boiler retrofitted with air staging, and the unburned carbon in ash can maintain at a desired level where the utilization of fly-ash as byproducts was not influenced.

  16. Thermal decomposition of heavy lanthanide 3-hydroxybenzoates in air and nitrogen atmospheres

    The conditions of thermal decomposition of heavy lanthanide complexes with 3-hydroxybenzoic acid in air and nitrogen atmospheres were studied. On heating the complexes of Gd, Dy, Ho, Yb and Lu decompose in three stages. First, the hydrated complexes lose crystallization water and the anhydrous salts heated in air are then transformed to Lnsub(2)Osub(3), or, in a nitrogen atmosphere, to Lnsub(2)Osub(3) and C. Complexes of Tb(III), Ho and Er are dehydrated in two stages during heating, and the anhydrous complexes are converted in air to Lnsub(2)Osub(3) and Tbsub(4)Osub(7), and in a nitrogen atmosphere to a mixture of oxides and C. The carbon content in the decomposition product is 9.7% for Gd and 19.6% for Ho. The dehydration of the complexes is accompanied by endothermic effects. The decomposition of 3-hydroxybenzoates is exothermic in air and endothermic in nitrogen. (author)

  17. Thermal protection of targeted air instillation in CT-guided radiofrequency ablation

    To evaluate targeted intraperitoneal air instillation for the protection of adjacent structures at high-risk liver metastasis sites. On the basis of an interdisciplinary indication for radiofrequency ablation (RFA), targeted air instillation (up to 200 cc) was performed in 6 patients with a total of 6 liver metastases over an anterior or right lateral access route with a 22 G Chiba needle for the distension of the structures as well as protection against thermal damage from RFA in the close relationship of liver lesions to the stomach or colon. In 6 patients (mean age approximately 66.3 years, 4 males, 2 females) with a risky location of a colorectal metastasis (liver segment III or VI), the targeted air instillation was performed between the liver and stomach (4 / 6) and colon (2 / 6). Protection against thermal damage was able to be established in 6 / 6 liver metastases prior to RFA. All tumor sites were ablated completely without the occurrence of complications requiring treatment. The additional instillation of air into the peritoneum for distension and thermal protection is a useful extension of the RFA technique, which allows successful ablation at high-risk liver tumor sites and also allows interventional radiologists to treat tumor manifestations closely related to the colon or stomach. (orig.)

  18. Properties of thermal air plasma with admixing of copper and carbon

    This paper deals with investigations of air plasma with admixing of copper and carbon. Model plasma source unit with real breaking arc was used for the simulation of real discharges, which can be occurred during sliding of Cu-C composite electrodes on copper wire at electromotive vehicles. The complex technique of plasma property studies is developed. From one hand, the radial profiles of temperature and electron density in plasma of electric arc discharge in air between Cu-C composite and copper electrodes in air flow were measured by optical spectroscopy techniques. From another hand, the radial profiles of electric conductivity of plasma mixture were calculated by solution of energy balance equation. It was assumed that the thermal conductivity of air plasma is not depending on copper or carbon vapor admixtures. The electron density is obtained from electric conductivity profiles by calculation in assumption of local thermodynamic equilibrium in plasma. Computed in such way radial profiles of electron density in plasma of electric arc discharge in air between copper electrodes were compared with experimentally measured profiles. It is concluded that developed techniques of plasma diagnostics can be reasonably used in investigations of thermal plasma with copper and carbon vapors

  19. Kinetic study of the thermal decomposition process of calcite particles in air and CO2 atmosphere

    Escardino Benlloch, Agustín; García Ten, Francisco Javier; Feliu Mingarro, Carlos; Saburit Llaudis, Alejandro; Cantavella Soler, Vicente

    2013-01-01

    The thermal decomposition process of calcite particles (0.45–3.60 mm average diameter), made up of porous agglomerates of very small CaCO3 microcrystals, was studied in the 975–1216 K temperature range. The experiments were carried out under isothermal conditions in air atmosphere, in CO2 atmosphere, as well as in a gas stream comprising different concentrations of air and CO2. An equation is proposed that relates the calcite conversion degree to both reaction time and operating condition...

  20. Thermal degradation of the vapours of organic nitrogen compounds in the presence of the air

    Following a quick survey of the literature on the products originated during the thermal degradation of some organic nitrogen compounds, the experimental results obtained by applying a technique previously used for other organic compounds are presented. The compounds investigated include: methyl and ethylamines at the origin of the bad smells of many gaseous wastes, trilaurylamine and tetraethylenediamine sometimes used in nuclear facilities. Attention is brought on the emission of noxious products during thermal degradation in the presence of the air, at various temperatures, viz. either usual combustion gases such as carbon monoxide, or nitro-derivatives such as hydrogen cyanide present whatever the compound investigated when temperatures are below 8500C

  1. Air flow and thermal comfort simulation studies of wind ventilated classrooms in Malaysia

    Rahman, S.A. [Malaysian Institut of Teknologi, Selangor (Malaysia). Kajian Sains Gunaan; Kannan, K.S. [Technology Univ. of Malaysia, Kuala Lumpur (Malaysia)

    1996-05-01

    A CFD software called VORTEX is used as a tool to simulate air flow and thermal comfort in naturally wind ventilated classrooms of an educational institution, which are at different locations, have different configurations and slightly differing outdoor environmental conditions. Simulations of the various classrooms are compared to get the most thermally comfortable and uncomfortable naturally ventilated classroom. An analysis of the simulations will be done, taking into consideration, among others, location of inlets and outlets and the sheltering effects of the surrounding built-up environment. Recommendations will then be made on how to improve the ventilation of the least comfortable room, based on hypothetical simulation results. (author)

  2. HVACMeter: Apportionment of HVAC Power to Thermal Zones and Air Handler Units

    Koh, Jason; Balaji, Bharathan; Gupta, Rajesh; Agarwal, Yuvraj

    2015-01-01

    Heating, Ventilation and Air Conditioning (HVAC) systems consume almost half of the total energy use of commercial buildings. To optimize HVAC energy usage, it is important to understand the energy consumption of individual HVAC components at fine granularities. However, buildings typically only have aggregate building level power and thermal meters. We present HVACMeter, a system which leverages existing sensors in commercial HVAC systems to estimate the energy consumed by individual compone...

  3. Thermal comfort in air-conditioned mosques in the dry desert climate

    Al-ajmi, Farraj F. [Department of Civil Engineering, College of Technological Studies, Shuwaikh 70654 (Kuwait)

    2010-11-15

    In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (T{sub n}) of the prayers is found to be 26.1 C, while that for PMV is 23.3 C. Discrepancy of these values is in fact about 2.8 C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait. (author)

  4. Evaluation of Single-Pass Photovoltaic-Thermal Air Collector with Rectangle Tunnel Absorber

    Goh L. Jin

    2010-01-01

    Full Text Available Problem statement: Photovoltaic solar cell generate electric by receiving sun light or solar irradiance. But solar cell received heat from solar irradiance as well and this will reduced the efficiency of the solar cell. The heat trap at the solar photovoltaic panel become waste energy. Approach: The solution for this was by adding a cooling system to the photovoltaic panel. The purpose of this study was to cool the solar cell in order to increase its electrical efficiency and also to produce heat energy in the form of hot air. Hot air can be used for drying applications. A single pass PVT with rectangle tunnel absorber has been developed. The rectangle tunnel acted as an absorber and was located at the back side of a standard photovoltaic panel. The dimension of the photovoltaic panel was 120×53 cm. The size of the rectangle tunnel was 27 units of tunnel bar with the size of 1.2×2.5×120 cm (width×tall×length and 12 units with 1.2×2.5×105.3 cm (width×tall×length. The rectangle tunnel was connected in parallel. The PVT collector has been tested using a solar simulator. Results: Electrical efficiency increased when the solar cell was cool by air flow. Solar photovoltaic thermal collector with rectangle tunnel absorber has better electrical and thermal efficiency compared to solar collector without rectangle tunnel absorber. Photovoltaic, thermal and combined photovoltaic thermal efficiency of 10.02, 54.70 and 64.72% at solar irradiance of 817.4 W m-2, mass flow rate of 0.0287 kg sec-1 at ambiant temperature of 25°C respectively has been obtained. Conclusion: The hybrid photovoltaic and thermal with rectangle tunnel as heat absorber shows higher performance compared to conventional PV/T system.

  5. Thermal properties in phase change wallboard room based on air conditioning cold storage

    陈其针; 刘鑫; 牛润萍; 王琳

    2009-01-01

    By comparing the thermal performance parameters of an ordinary wall room with a phase change wall (PCW) room,the effect of phase change wallboard on the fluctuation of temperature in air-conditioning room in summer was studied. And PCW room and an ordinary wall room,which are cooled by air-conditioner,were built up. Differential scanning calorimetry (DSC) was used to test the temperature field and heat flow fluctuation in these rooms. Through analyzing the data tested,it is found that the mean temperature of PCW is lower than that of ordinary wall room by 1-2 ℃,and PCW can lower the heat flow by 4.6 W/m2. Combining phase change material to building envelope can lower the indoor temperature,make the room thermal comfortable,and cut down the turn-on-and-off frequency of air-conditioner,the primary investment and operating costs. It alleviates urgent need of the electric power. Building envelope which contains phase change wallboard can improve the indoor thermal environment,and decrease energy consumption in buildings. Phase change wallboard can make impressive effect on energy efficiency of buildings.

  6. Impact Analysis of Air Pollutant Emission Policies on Thermal Coal Supply Chain Enterprises in China

    Xiaopeng Guo

    2014-12-01

    Full Text Available Spurred by the increasingly serious air pollution problem, the Chinese government has launched a series of policies to put forward specific measures of power structure adjustment and the control objectives of air pollution and coal consumption. Other policies pointed out that the coal resources regional blockades will be broken by improving transportation networks and constructing new logistics nodes. Thermal power takes the largest part of China’s total installed power generation capacity, so these policies will undoubtedly impact thermal coal supply chain member enterprises. Based on the actual situation in China, this paper figures out how the member enterprises adjust their business decisions to satisfy the requirements of air pollution prevention and control policies by establishing system dynamic models of policy impact transfer. These dynamic analyses can help coal enterprises and thermal power enterprises do strategic environmental assessments and find directions of sustainable development. Furthermore, the policy simulated results of this paper provide the Chinese government with suggestions for policy-making to make sure that the energy conservation and emission reduction policies and sustainable energy policies can work more efficiently.

  7. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Sabanskis A.

    2016-04-01

    Full Text Available Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  8. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Sabanskis, A.; Virbulis, J.

    2016-04-01

    Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  9. Calculation of transport coefficients of air-water vapor mixtures thermal plasmas used in circuit breakers

    KOHIO Niéssan

    2014-12-01

    Full Text Available In this paper we calculate the transport coefficients of plasmas formed by air and water vapor mixtures. The calculation, which assume local thermodynamic equilibrium (LTE are performed in the temperature range from 500 to 12000 K. We use the Gibbs free energy minimization method to determine the equilibrium composition of the plasmas, which is necessary to calculate the transport coefficients. We use the Chapman-Enskog method to calculate the transport coefficients. The results are presented and discussed according to the rate of water vapor. The results of the total thermal conductivity and electrical conductivity show in particular that the increasing of the rate of water vapor in air can be interesting for power cut. This could be improve the performance of plasma during current breaking in air contaminate by the water vapor.

  10. Preliminary results of thermal igniter experiments in H2-air-steam environments

    Thermal igniters (glow plugs), proposed by the Tennessee Valley Authority for intentional ignition of hydrogen in nuclear reactor containment, have been tested for functionability in mixtures of air, hydrogen, and steam. Test environments included 6% to 16% hydrogen concentrations in air, and 8%, 10%, and 12% hydrogen in mixtures with 30% and 40% steam fractions. All were conducted in a 10.6 ft3 insulated pressure vessel. For all of these tests the glow plug successfully initiated combustion. Dry air/hydrogen tests exhibited a distinct tendency for complete combustion at hydrogen concentrations between 8% and 9%. Steam suppressed both peak pressures and completeness of combustion. No combustion could be initiated at or above a 50% steam fraction. Circulation of the mixture with a fan increased the completeness of combustion. The glow plug showed no evidence of performance degradation throughout the program

  11. Impact of summer office set air-conditioning temperature on energy consumption and thermal comfort

    刘红; 马小磊; 高亚峰

    2009-01-01

    To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.

  12. Experimental evidence of the thermal effect of lubricating oil sprayed in sliding-vane air compressors

    Gianluca Valenti

    2014-11-01

    Full Text Available A way to increase the efficiency of positive-displacement air compressor is spraying the lube oil to exploit it not only as lubricating and sealing agent but also as thermal ballast. This work seeks the experimental evidence in sliding-vane compressors by measuring the air standard volume flow rate and the electrical power input of three diverse configurations. The first configuration, taken as the reference, employs a conventional injection system comprising calibrated straight orifices. The other two, referred to as advanced, adopt smaller orifices and pressure-swirl full-cone nozzles designed for the purpose; the third configuration utilizes a pump to boost the oil pressure. The laser imagining technique shows that the nozzles generate sprays that break-up within a short distance into spherical droplets, ligaments, ramifications and undefined structures. Tests on the packaged compressors reveal that the advanced configurations provide almost the same air flow rate while utilizing half of the oil because the sprays generate a good sealing. Moreover, the sprayed oil is acting as a thermal ballast because the electrical input is reduced by 3.5% and 3.0%, respectively, if the pump is present or not , while the specific energy requirement, accounting for the slightly reduced air flow, by 2.4% and 2.9%, respectively.

  13. Thermal Sizing of Heat Exchanger Tubes for Air Natural Convective Cooling System of Emergency Cooling Tank

    For the long operation of secondary passive cooling system, however, water level goes down by evaporation in succession at emergency cooling tank. At the end there would be no place to dissipate heat from condensation heat exchanger. Therefore, steam cooling heat exchanger is put on the top of emergency cooling tank to maintain appropriate water level by collecting evaporating steam. Steam cooling heat exchanger is installed inside an air chimney and evaporated steam is cooled down by air natural convection. In this study, thermal sizing of steam cooling heat exchanger under air natural convection was conducted by TSCON program for the design of experimental setup as shown in Fig. 2. Thermal sizing of steam cooling heat exchanger tube under air natural convection was conducted by TSCON program for the design of experimental setup. 25 - 1' tubes which has a length 1687 mm was determined as steam cooling heat exchanger at 2 kW heat load and 100 liter water pool in emergency cooling tank (experimental limit condition). The corresponding width of two tubes is 50 mm and has 5 by 5 tube array for heat exchanger

  14. Experimental Study Abour How the Thermal Plume Affects the Air Quality a Person Breathes

    Olmedo, Inés; Nielsen, Peter V.; Ruiz de Adana, Manuel;

    2011-01-01

    .10 m (length), 3.2 m (width), 2.7 m (height). The incoming air is distributed through a wall-mounted displacement diffuser. A breathing thermal manikin exhaling through the mouth and inhaling through the nose was used. A tracer gas, N2O, was used to simulate the gaseous substances, which might be......The Personal Micro Environment (PME) depends directly on the heat transfer in the surrounding environment. For the displacement ventilation systems the convective transport mechanism, which is found in the thermal plume around a person, influences the human exposure to pollutants. The aim of this...... research is to increase the knowledge of how the thermal plume generated by a person affects the PME and therefore the concentration of contaminants in the inhalation area. An experimental study in a displacement ventilation room was carried out. Experiments were developed in a full scale test chamber 4...

  15. The effect of air temperature and human thermal indices on mortality in Athens, Greece

    Nastos, Panagiotis T.; Matzarakis, Andreas

    2012-05-01

    This paper investigates whether there is any association between the daily mortality for the wider region of Athens, Greece and the thermal conditions, for the 10-year period 1992-2001. The daily mortality datasets were acquired from the Hellenic Statistical Service and the daily meteorological datasets, concerning daily maximum and minimum air temperature, from the Hellinikon/Athens meteorological station, established at the headquarters of the Greek Meteorological Service. Besides, the daily values of the thermal indices Physiologically Equivalent Temperature (PET) and Universal Thermal Climate Index (UTCI) were evaluated in order to interpret the grade of physiological stress. The first step was the application of Pearson's χ 2 test to the compiled contingency tables, resulting in that the probability of independence is zero ( p = 0.000); namely, mortality is in close relation to the air temperature and PET/UTCI. Furthermore, the findings extracted by the generalized linear models showed that, statistically significant relationships ( p PET, UTCI and mortality exist on the same day. More concretely, on one hand during the cold period (October-March), a 10°C decrease in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 13%, 15%, 2%, 7% and 6% of the probability having a death, respectively. On the other hand, during the warm period (April-September), a 10°C increase in daily maximum air temperature, minimum air temperature, temperature range, PET and UTCI is related with an increase 3%, 1%, 10%, 3% and 5% of the probability having a death, respectively. Taking into consideration the time lag effect of the examined parameters on mortality, it was found that significant effects of 3-day lag during the cold period appears against 1-day lag during the warm period. In spite of the general aspect that cold conditions seem to be favourable factors for daily mortality, the air temperature and PET

  16. Heating, ventilating, and air conditioning deactivation thermal analysis of PUREX Plant

    Chen, W.W.; Gregonis, R.A. [Westinghouse Hanford Company, Richland, WA (United States)

    1997-08-01

    Thermal analysis was performed for the proposed Plutonium Uranium Extraction Plant exhaust system after deactivation. The purpose of the analysis was to determine if enough condensation will occur to plug or damage the filtration components. A heat transfer and fluid flow analysis was performed to evaluate the thermal characteristics of the underground duct system, the deep-bed glass fiber filter No. 2, and the high-efficiency particulate air filters in the fourth filter building. The analysis is based on extreme variations of air temperature, relative humidity, and dew point temperature using 15 years of Hanford Site weather data as a basis. The results will be used to evaluate the need for the electric heaters proposed for the canyon exhaust to prevent condensation. Results of the analysis indicate that a condition may exist in the underground ductwork where the duct temperature can lead or lag changes in the ambient air temperature. This condition may contribute to condensation on the inside surfaces of the underground exhaust duct. A worst case conservative analysis was performed assuming that all of the water is removed from the moist air over the inside surface of the concrete duct area in the fully developed turbulent boundary layer while the moist air in the free stream will not condense. The total moisture accumulated in 24 hours is negligible. Water puddling would not be expected. The results of the analyses agree with plant operating experiences. The filters were designed to resist high humidity and direct wetting, filter plugging caused by slight condensation in the upstream duct is not a concern. 19 refs., 2 figs.

  17. INVENTORY ABSTRACTION

    G. Ragan

    2001-12-19

    The purpose of the inventory abstraction, which has been prepared in accordance with a technical work plan (CRWMS M&O 2000e for ICN 02 of the present analysis, and BSC 2001e for ICN 03 of the present analysis), is to: (1) Interpret the results of a series of relative dose calculations (CRWMS M&O 2000c, 2000f). (2) Recommend, including a basis thereof, a set of radionuclides that should be modeled in the Total System Performance Assessment in Support of the Site Recommendation (TSPA-SR) and the Total System Performance Assessment in Support of the Final Environmental Impact Statement (TSPA-FEIS). (3) Provide initial radionuclide inventories for the TSPA-SR and TSPA-FEIS models. (4) Answer the U.S. Nuclear Regulatory Commission (NRC)'s Issue Resolution Status Report ''Key Technical Issue: Container Life and Source Term'' (CLST IRSR) key technical issue (KTI): ''The rate at which radionuclides in SNF [spent nuclear fuel] are released from the EBS [engineered barrier system] through the oxidation and dissolution of spent fuel'' (NRC 1999, Subissue 3). The scope of the radionuclide screening analysis encompasses the period from 100 years to 10,000 years after the potential repository at Yucca Mountain is sealed for scenarios involving the breach of a waste package and subsequent degradation of the waste form as required for the TSPA-SR calculations. By extending the time period considered to one million years after repository closure, recommendations are made for the TSPA-FEIS. The waste forms included in the inventory abstraction are Commercial Spent Nuclear Fuel (CSNF), DOE Spent Nuclear Fuel (DSNF), High-Level Waste (HLW), naval Spent Nuclear Fuel (SNF), and U.S. Department of Energy (DOE) plutonium waste. The intended use of this analysis is in TSPA-SR and TSPA-FEIS. Based on the recommendations made here, models for release, transport, and possibly exposure will be developed for the isotopes that would be the highest

  18. Novel fragmentation model for pulverized coal particles gasification in low temperature air thermal plasma

    Jovanović Rastko D.

    2016-01-01

    Full Text Available New system for start-up and flame support based on coal gasification by low temperature air thermal plasma is planned to supplement current heavy oil system in Serbian thermal power plants in order to decrease air pollutions emission and operational costs. Locally introduced plasma thermal energy heats up and ignites entrained coal particles, thus starting chain process which releases heat energy from gasified coal particles inside burner channel. Important stages during particle combustion, such as particle devolatilisation and char combustion, are described with satisfying accuracy in existing commercial CFD codes that are extensively used as powerful tool for pulverized coal combustion and gasification modeling. However, during plasma coal gasification, high plasma temperature induces strong thermal stresses inside interacting coal particles. These stresses lead to “thermal shock” and extensive particle fragmentation during which coal particles with initial size of 50-100 m disintegrate into fragments of at most 5-10 m. This intensifies volatile release by a factor 3-4 and substantially accelerates the oxidation of combustible matter. Particle fragmentation, due to its small size and thus limited influence on combustion process is commonly neglected in modelling. The main focus of this work is to suggest novel approach to pulverized coal gasification under high temperature conditions and to implement it into commercial comprehensive code ANSYS FLUENT 14.0. Proposed model was validated against experimental data obtained in newly built pilot scale D.C plasma burner test facility. Newly developed model showed very good agreement with experimental results with relative error less than 10%, while the standard built-in gasification model had error up to 25%.

  19. Performance analysis of a hybrid photovoltaic thermal double pass air collector using ANN

    This paper presents the use of artificial neural network for performance analysis of a semi transparent hybrid photovoltaic thermal double pass air collector for four weather conditions (a, b, c and d type) of New Delhi. The MATLAB 7.1 neural networks toolbox has been used for defining and training of ANN for calculations of thermal energy, electrical energy, overall thermal energy and overall exergy. The ANN model uses ambient air temperature, global solar radiation, diffuse radiation and number of clear days as input parameters for four weather conditions. The transfer function, neural network configuration and learning parameters have been selected based on highest convergence during training and testing of network. About 2000 sets of data from four weather stations (Bangalore, Mumbai, Srinagar, and Jodhpur) have been given as input for training and data of the fifth weather station (New Delhi) has been used for testing purpose. It has been observed that the best transfer function for a given configuration is lag's. The feed forward back-propagation algorithm has been used in this analysis. Further the results of ANN model have been compared with analytical values on the basis of root mean square error. (authors)

  20. Analysis of thermal comfort and indoor air quality in a mechanically ventilated theatre

    Kavgic, M.; Mumovic, D.; Young, A. [The Bartlett School of Graduate Studies, University College London, Gower Street, London, WC1E 6BT, England (United Kingdom); Stevanovic, Z. [Institute of Nuclear Sciences - Vinca, P.O. Box 522, 11001 Belgrade (RS)

    2008-07-01

    Theatres are the most complex of all auditorium structures environmentally. They usually have high heat loads, which are of a transient nature as audiences come and go, and from lighting which changes from scene to scene, and they generally have full or nearly full occupancy. Theatres also need to perform well acoustically, both for the spoken word and for music, and as sound amplification is less used than in other auditoria, background noise control is critically important. All these factors place constraints on the ventilation design, and if this is poor, it can lead to the deterioration of indoor air quality and thermal comfort. To analyse the level of indoor air quality and thermal comfort in a typical medium-sized mechanically ventilated theatre, and to identify where improvements could typically be made, a comprehensive post-occupancy evaluation study was carried out on a theatre in Belgrade. The evaluation, based on the results of monitoring (temperature, relative humidity, CO{sub 2}, air speed and heat flux) and modelling (CFD), as well as the assessment of comfort and health as perceived by occupants, has shown that for most of the monitored period the environmental parameters were within the standard limits of thermal comfort and IAQ. However, two important issues were identified, which should be borne in mind by theatre designers in the future. First, the calculated ventilation rates showed that the theatre was over-ventilated, which will have serious consequences for its energy consumption, and secondly, the displacement ventilation arrangement employed led to higher than expected complaints of cold discomfort, probably due to cold draughts around the occupants' feet. (author)

  1. Study on the Thermal Effects and Air Quality Improvement of Green Roof

    Heng Luo

    2015-03-01

    Full Text Available Heat island phenomenon and air quality deterioration issues are two major problems that have occurred during the process of urbanization, especially in developing countries. A number of measures have been proposed, among which roof greening is considered as a promising one due to its outstanding performance in thermal effects as well as air quality improvement. A self-maintenance system, termed the Green Roof Manager (GRM, which comprises the irrigation and shadowing subsystems, is proposed in this paper, focusing on the automatic and reliable operation of the roof greening system rather than exploiting new plant species. A three month long experiment was set up, resulting in the observation that a 14.7% of, on average, temperature reduction can be achieved in summer after deploying the GRM system. During a 24-hour monitoring experiment the PM2.5 concentrations above the GRM was reduced by up to 14.1% over the bare roof.

  2. Control of ammonia air pollution through the management of thermal processes in cowsheds.

    Bleizgys, Rolandas; Bagdoniene, Indre

    2016-10-15

    Experimental researches performed in manufacturing cowsheds have demonstrated a variation of ammonia concentration and the factors influencing this most during different periods of the year. The process of ammonia evaporation from manure is influenced by many varying and interrelated factors with temperature and the intensity of air ventilation being the most critical ones. The influence of these factors on the process of ammonia evaporation was established by laboratory researches. An increase in temperature results in an exponential increase in ammonia emission, whereas the dependence of the emission on the air velocity is best expressed by a second degree polynomial. The results obtained may be used as a forecast of the ammonia emissions from cowsheds during different periods of the year. Intensive ventilation is required for the removal of excess moisture from the housing, and this limits the possibilities to reduce ammonia emissions by controlling the intensity of ventilation. A reduction in the amount of ventilation is only recommended if the air quality indices meet the requirements applied to the housing. Better opportunities to reduce ammonia emissions are provided through management of the thermal processes in a cowshed. If the average annual air temperature (11.3°C) is reduced by one degree in a cubicle housing cowshed, the ammonia emissions will decrease by 10%. PMID:27350091

  3. THERMAL TREATMENT WITH HOT AIR IN THE CONTROL OF FRUIT FLY IN SAPOTA

    João Vilian de Moraes Lima Marinus

    2008-08-01

    Full Text Available One of the main postharvest problems of the sapota (Achras sapota L. is caused by the fruit fly (Ceratitis capitata, affecting its quality and commercialization. With this experiment, the objective was to evaluate the effect of hot air as thermal treatment in the control of immature phases of Ceratitis capitata and the fruit quality. The research was carried out at Entomology Laboratory – Centro de Ciências Agrárias, UFPB, Areia-PB. It was made the damaging of fruits with eggs inoculation of Ceratitis capitata and after three days the fruits were treated in hot air at temperatures of 46±1°C and 50±1°C, during 30, 45, 60, 75 and 90 minutes. Hot air was injected in the chamber using an equipment of the Skill mark. It was used a randomized design, in factorial scheme of 2x5+1 (two temperatures, five times of exhibition and one control, with four replications. The treatment with hot air was efficient to control the immature phases of C. capitata during 75 and 90 minutes of exposure and didn't affect the physical and chemical qualities of the sapota fruits.

  4. Containment vessel, its auxiliary system and plant air conditioning system of advanced thermal reactor Fugen

    The functional requirement for, the design and the construction of, and the functional test on the containment vessel, its auxiliary system, the plant air conditioning and ventilation system of the advanced thermal reactor, Fugen, are described in detail. The main specifications of the containment vessel are as follows: The type enclosed cylinder, the maximum operating pressure 1.35 kg/cm2g, the maximum operating temperature 100 deg C, the leak rate 0.4%/day, the inner diameter 36 m. The height 64 m, the volume 40,900 m3, and the material JIS G3118, SGV-49. The containment vessel is provided with an hatch of 5 m diameter for carrying equipments in two air locks, many high and low voltage cable penetrations, pipe penetrations, a transfer shoot and isolation values. The functions and the specifications of the containment vessel and its auxiliary equipments are explained. The relating auxiliary systems are composed of the containment vessel spray system, the pool facility for steam blow-down, the recirculation system for the air in the vessel, the annulus evacuation system and its pressure control devices, the pressure measuring instruments and pressure relief valves and the temperature measuring devices for the containment vessel, and the object, function, layout and installation of these systems are explained. Concerning the air conditioning system, each main building has the special subsystem, and they are introduced. The progress stage of construction works and the procedure and results of the functional test at the site are described. (Nakai, Y.)

  5. Thermal Decomposition and Dehydration Kinetics of Tetra(piperidinium)Octamolybdate Tetrahydrate in Air

    KU Zong-Jun; ZHANG Zhong-Hai; ZHANG Zhi-Guo; WANG Li-Na; ZHANG Ke-Li

    2008-01-01

    Thermal decomposition of tetra(piperidinium)octamolybdate tetrahydrate,[CsH10NH2]4[Mo8O26]·4H2O,was investigated in air by means of TG-DTG/DTA.DSC,TG-IR and SEM.TG-DTG/DTA curves showed that the decomposition proceeded through three well-defined steps with DTA peaks closely corresponding to mass loss obtained.Kinetics analysis of its dehydration step Was performed under non-isothermal conditions.The dehydrationactivation energy was calculated through Friedman and Flynn-Wall-Ozawa(FWO)methods,and the best-fit dehydration kinetic model function was estimated through the multiple linear regression method.The activation energy for the dehydration step of[C5H10NH2]4[MosO26]·4H2O was 139.7 kJ/mol.The solid particles became smaller accompanied by the thermal decomposition of the title compound.

  6. An experimental investigation of performance of a double pass solar air heater with thermal storage medium

    Ali Hafiz Muhammad

    2015-01-01

    Full Text Available The performance of a double pass solar air heater was experimentally investigated using four different configurations. First configuration contained only absorber plate whereas copper tubes filled with thermal storage medium (paraffin wax were added on the absorber plate in the second configuration. Aluminum and steel rods as thermal enhancer were inserted in the middle of paraffin wax of each tube for configurations three and four respectively. Second configuration provided useful heat for about 1.5 hours after the sunset compared to first configuration. Configurations three and four provided useful heat for about 2 hours after the sunset. The maximum efficiency of about 96% was achieved using configuration three (i.e. using Aluminum rods in the middle of copper tubes filled with paraffin wax.

  7. Thermal partition of two asymmetric discrete heat sources by cold air curtain

    DENG Quan-wei; DENG Qi-hong

    2005-01-01

    A partition solution implemented by a cold air curtain for two asymmetric discrete heat sources in a twodimensional rectangular enclosure was numerically studied. Main attentions were focused on the effects of Reynolds number, Grashof number, separation distance between heat sources, and buoyancy ratio. It is found that the airflow and heat transfer are not only determined by governing parameters, but also affected by boundary conditions. It is also found that nearly symmetry of flow structure corresponds to nearly thermal partition, and the symmetry can be enhanced when Reynolds number, separation distance and buoyancy ratio increase. In addition, it is observed that there is a minimum Reynolds number for obtaining nearly thermal partition, which increases when Grashof number increases.

  8. Influence of Urban Microclimate on Air-Conditioning Energy Needs and Indoor Thermal Comfort in Houses

    Feng-Chi Liao

    2015-01-01

    Full Text Available A long-term climate measurement was implemented in the third largest city of Taiwan, for the check of accuracy of morphing approach on generating the hourly data of urban local climate. Based on observed and morphed meteorological data, building energy simulation software EnergyPlus was used to simulate the cooling energy consumption of an air-conditioned typical flat and the thermal comfort level of a naturally ventilated typical flat. The simulated results were used to quantitatively discuss the effect of urban microclimate on the energy consumption as well as thermal comfort of residential buildings. The findings of this study can serve as a reference for city planning and energy management divisions to study urban sustainability strategies in the future.

  9. Thermal performance analysis of optimized hexagonal finned heat sinks in impinging air jet

    Yakut, Kenan; Yeşildal, Faruk; Karabey, Altuǧ; Yakut, Rıdvan

    2016-04-01

    In this study, thermal performance analysis of hexagonal finned heat sinks which optimized according to the experimental design and optimization method of Taguchi were investigated. Experiments of air jet impingement on heated hexagonal finned heat sinks were carried out adhering to the L18(21*36) orthogonal array test plan. Optimum geometries were determined and named OH-1, OH-2. Enhancement efficiency with the first law of thermodynamics was analyzed for optimized heat sinks with 100, 150, 200 mm heights of hexagonal fin. Nusselt correlations were found out and variations of enhancement efficiency with Reynolds number presented in η-Re graphics.

  10. RESULTS OF INVESTIGATIONS ON THERMAL CHARACTERISTICS OF AIR HEATER BUNDLE MADE OF BIMETALLIC FINNED TUBES

    V. B. Kuntysh

    2014-01-01

    Full Text Available The paper presents a scheme and description of a new aerodynamic stand that has a 300x300 mm cross-section operating channel. The stand is used for studying thermal and aerodynamic characteristics of bundles made of finned tubes of actual dimensions in crossflow. The paper provides results of an exploratory test pertaining to heat transfer and resistance of four row staggered bundle made of tubes with aluminium spiral fins having outside diameter of 26 mm which are used in the systems of ventilation, air-conditioning and heating of buildings and also in transport heat exchangers.

  11. Thermal energy storages analysis for high temperature in air solar systems

    In this paper a high temperature thermal storage in a honeycomb solid matrix is numerically investigated and a parametric analysis is accomplished. In the formulation of the model it is assumed that the system geometry is cylindrical, the fluid and the solid thermo physical properties are temperature independent and radiative heat transfer is taken into account whereas the effect of gravity is neglected. Air is employed as working fluid and the solid material is cordierite. The evaluation of the fluid dynamic and thermal behaviors is accomplished assuming the honeycomb as a porous medium. The Brinkman–Forchheimer–extended Darcy model is used in the governing equations and the local thermal non equilibrium is assumed. The commercial CFD Fluent code is used to solve the governing equations in transient regime. Numerical simulations are carried out with storage medium for different mass flow rates of the working fluid and different porosity values. Results in terms of temperature profiles, temperatures fields and stored thermal energy as function of time are presented. The effects of storage medium, different porosity values and mass flow rate on stored thermal energy and storage time are shown. - Highlights: • HTTES in a honeycomb solid matrix is numerically investigated. • The numerical analysis is carried out assuming the honeycomb as a porous medium. • The Brinkman–Forchheimer–extended Darcy model is used in the governing equations. • Results are carried out for different mass flow rates and porosity values. • The main effect is due to the porosity which set the thermal energy storage value

  12. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  13. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber

    Hejcik J.; Pech O.; Charvat P.

    2013-01-01

    The paper deals with experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solarabsorber. The main purpose of heat storage in solar thermal systems is to store heat when the supply of solar heat exceeds demand and release it when otherwise. A number of heat storage materials can be used for this purpose; the phase change materials among them. Short-term latent heat thermal storage integrated with the solar absorber can sta...

  14. Evaluation of air temperature distribution using thermal image under conditions of nocturnal radiative cooling in winter season over Shikoku area

    Using the thermal images offered by the infra-red thermometer and the LANDSAT, the air temperature distribution over mountainous regions were estimated under conditions of nocturnal radiative cooling in the winter season. The thermal image analyses by using an infra-red thermometer and the micrometeological observation were carried out around Zentsuji Kagawa prefecture. At the same time, the thermal image analyses were carried out by using the LANDSAT data. The LANDSAT data were taken on Dec. 7, 1984 and Dec. 5, 1989. The scenes covered the west part of Shikoku, southwest of Japan.The results were summarized as follows:Values of the surface temperature of trees, which were measured by an infra-red thermometer, were almost equal to the air temperature. On the other hand, DN values detected by LANDSAT over forest area were closely related with air temperature observed by AMeDAS. Therefore, it is possible to evaluate instantaneously a spatial distribution of the nocturnal air temperature from thermal image.The LANDSAT detect a surface temperature over Shikoku area only at 21:30. When radiative cooling was dominant, the thermal belt and the cold air lake were already formed on the mountain slopes at 21:30. Therfore, it is possible to estimate the characteristic of nocturnal temperature distribution by using LANDSAT data.It became clear that the temperature distribution estimated by thermal images offered by the infra-red thermometer and the LANDSAT was useful for the evaluation of rational land use for winter crops

  15. Impact of facially applied air movement on the development of the thermal plume above a sitting occupant

    Zukowska, Daria; Melikov, Arsen Krikor; Popiolek, Zbigniew J.; Spletsteser, Joanna

    2011-01-01

    convection boundary layer enveloping the body and caused scattering in the measured values of air speed and temperature excess in the plume. In comparison with the case without airflow, the integral characteristics including volume flux, momentum flux, buoyancy force density and enthalpy flux were greater......In the future the implementation of low power office equipment in practice will make thermal plumes generated by occupants one of the dominant flows affecting the air distribution in spaces. Advanced air distribution methods, such as personalized ventilation, are expected to become widely...... implemented in practice. In this study the impact of locally applied airflow on the thermal plume generated by a sitting human body was investigated. The experiment was performed in a climate chamber with upward piston flow. A thermal manikin was sitting on a computer chair behind a table. The air speed and...

  16. Overview of direct air free cooling and thermal energy storage potential energy savings in data centres

    In the last years the total energy demand of data centres has experienced a dramatic increase which is expected to continue. This is why data centres industry and researchers are working on implementing energy efficiency measures and integrating renewable energy to overcome energy dependence and to reduce operational costs and CO2 emissions. The cooling system of these unique infrastructures can account for 40% of the total energy consumption. To reduce the energy consumption, free cooling strategies are used more and more, but so far there has been little research about the potential of thermal energy storage (TES) solutions to match energy demand and energy availability. Hence, this work intends to provide an overview of the potential of the integration of direct air free cooling strategy and TES systems into data centres located at different European locations. For each location, the benefit of using direct air free cooling is evaluated energetically and economically for a data centre of 1250 kW. The use of direct air free cooling is shown to be feasible. This does not apply the TES systems by itself. But when using TES in combination with an off-peak electricity tariff the operational cooling cost can be drastically reduced. - Highlights: • The total annual hours for direct air free cooling in data centres are calculated. • The potential of TES integration in data centres is evaluated. • The implementation of TES to store the ambient air cold is not recommended. • TES is feasible if combined with redundant chillers and off-peak electricity price. • The cooling electricity cost is being reduced up to 51%, depending on the location

  17. Thermal decomposition of sugarcane straw, kinetics and heat of reaction in synthetic air.

    Rueda-Ordóñez, Yesid Javier; Tannous, Katia

    2016-07-01

    The aim of this work was to analyze the thermal decomposition, kinetics and heat of reaction of sugarcane straw in synthetic air by thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG and DSC experiments were carried out using heating rates of 2.5°C/min, 5°C/min, and 10°C/min, and particle diameter of 0.250mm. In the study of the smoldering reaction were identified three consecutive stages, drying, oxidative pyrolysis, and combustion. Thus, the kinetic pathway was composed by six independent parallel reactions, three for each stage after drying, in which the activation energies were 176, 313, 150, 80, 150, and 100kJ/mol. The heat of reaction in synthetic air was completely exothermic releasing 8MJ/kg. The modeled curves of thermal decomposition of sugarcane straw presented good agreement with experimental data. Then, the kinetic parameters obtained could be used to analyze different processes involving smoldering. PMID:27019126

  18. Thermal effect of lubricating oil in positive-displacement air compressors

    The isentropic efficiency of positive-displacement compressors may be improved in order to follow an increasing demand for energy savings. This work analyzes the thermal effect of the lubricating oil presence in the air during compression with the scope of exploiting it as a thermal ballast to mitigate both the gas temperature rise and its compression work. The bibliographic review shows that other authors suggested that oil can have positive effects if properly injected. Here an energy balance analysis is executed with the scope of deriving relations for the gas–liquid compression in analogy with those typical for the gas-only compression and of confirming that ideally the liquid presence may have beneficial effects, making the gas–liquid compression even better than 1- and 2-time intercooled gas compressions. Given these positive results, a heat transfer analysis is conducted to model the thermal interaction between gas and oil droplets within a mid-size rotary vane air compressor. A droplet diameter of the order of 100 μm leads to large reductions of both temperature increase and compression work: air can exit the discharge port at a temperature as low as 60 °C and compression work can be lowered by 23–28% with respect to conventional compressors. Finally, a test rig is constructed and operated to investigate a large-flow and large-angle oil nozzle taken from the market showing that, at the operating conditions of a compressor, oil breaks up into small droplets and undefined structures with large exchange surfaces. -- Highlights: ► Exploitation of thermal effect of oil in gas compressors is assessed numerically. ► Oil in 100 μm-diameter droplets mitigates effectively the gas temperature rise. ► Discharge temperature and compression work result to be much smaller than typical. ► An experimental setup is used to investigate oil atomization via commercial nozzles. ► A tested nozzle creates fine oil droplets and structures at conditions of

  19. BALWOIS: Abstracts

    anthropogenic pressures and international shared water. Here are the 320 abstracts proposed by authors and accepted by the Scientific Committee. More than 200 papers are presented during the Conference on 8 topics related to Hydrology, Climatology and Hydro biology: - Climate and Environment; - Hydrological regimes and water balances; - Droughts and Floods; -Integrated Water Resources Management; -Water bodies Protection and Eco hydrology; -Lakes; -Information Systems for decision support; -Hydrological modelling. Papers relevant to INIS are indexed separately

  20. Premixed CH4/O2-enriched air combustion: Identification of thermal, chemical and aerodynamic effects

    Most, J.-M.; Dahikar, S.; Pal, S.; Claverie, A.; Denis, D.; Pillier, L.; de Persis, S.

    2012-11-01

    This work contributes to the evaluation of a new innovative process focused on the reduction of the cost of a post-combustion capture of CO2 in a Carbon Capture and Storage system (CCS). The process based on the separation of dried fumes composed mainly by CO2 and N2 by using membranes, which should lead to a lower energetic separation cost than amines. But the membranes become efficient if the upstream CO2 concentration is higher than 30% at their entrance that requires enriching the oxidizer flow by O2. To maintain the exhaust temperature compatible with materials thermal resistance, the reactants are diluted by a recirculation of a part of the flue gases (like N2/O2/CO2). But, the chemical kinetic, the energetic efficiencies, the radiation transfer, the transport and thermal properties of the flow can be affected by CO2. The objective of this work will be to identify the behaviour of the combustion of premixed CH4/O2-enriched air, both diluted in N2 and CO2 and to determine the combustion parameters. This allows to recover the CH4/air conditions in terms of CO2 concentration in reactants, O2 excess, dilution rate, temperature of the reactants, etc. Experiments are performed on the laminar premixed flame using counterflow burner. To characterize the combustion behaviour, the flammability limits are determined and flame thickness and position are measured from PLIF-OH diagnostic. Further, CHEMKIN simulations are performed to check the validity of the GRI3.0 chemical kinetic mechanism for premixed CH4/air synthetic combustion and identify the leading phenomena.

  1. Premixed CH4/O2-enriched air combustion: Identification of thermal, chemical and aerodynamic effects

    This work contributes to the evaluation of a new innovative process focused on the reduction of the cost of a post-combustion capture of CO2 in a Carbon Capture and Storage system (CCS). The process based on the separation of dried fumes composed mainly by CO2 and N2 by using membranes, which should lead to a lower energetic separation cost than amines. But the membranes become efficient if the upstream CO2 concentration is higher than 30% at their entrance that requires enriching the oxidizer flow by O2. To maintain the exhaust temperature compatible with materials thermal resistance, the reactants are diluted by a recirculation of a part of the flue gases (like N2/O2/CO2). But, the chemical kinetic, the energetic efficiencies, the radiation transfer, the transport and thermal properties of the flow can be affected by CO2. The objective of this work will be to identify the behaviour of the combustion of premixed CH4/O2-enriched air, both diluted in N2 and CO2 and to determine the combustion parameters. This allows to recover the CH4/air conditions in terms of CO2 concentration in reactants, O2 excess, dilution rate, temperature of the reactants, etc. Experiments are performed on the laminar premixed flame using counterflow burner. To characterize the combustion behaviour, the flammability limits are determined and flame thickness and position are measured from PLIF-OH diagnostic. Further, CHEMKIN simulations are performed to check the validity of the GRI3.0 chemical kinetic mechanism for premixed CH4/air synthetic combustion and identify the leading phenomena.

  2. Conceptual design and engineering studies of adiabatic compressed air energy storage (CAES) with thermal energy storage

    Hobson, M. J.

    1981-11-01

    The objective of this study was to perform a conceptual engineering design and evaluation study and to develop a design for an adiabatic CAES system using water-compensated hard rock caverns for compressed air storage. The conceptual plant design was to feature underground containment for thermal energy storage and water-compensated hard rock caverns for high pressure air storage. Other design constraints included the selection of turbomachinery designs that would require little development and would therefore be available for near-term plant construction and demonstration. The design was to be based upon the DOE/EPRI/PEPCO-funded 231 MW/unit conventional CAES plant design prepared for a site in Maryland. This report summarizes the project, its findings, and the recommendations of the study team; presents the development and optimization of the plant heat cycle and the selection and thermal design of the thermal energy storage system; discusses the selection of turbomachinery and estimated plant performance and operational capability; describes the control system concept; and presents the conceptual design of the adiabatic CAES plant, the cost estimates and economic evaluation, and an assessment of technical and economic feasibility. Particular areas in the plant design requiring further development or investigation are discussed. It is concluded that the adiabatic concept appears to be the most attractive candidate for utility application in the near future. It is operationally viable, economically attractive compared with competing concerns, and will require relatively little development before the construction of a plant can be undertaken. It is estimated that a utility could start the design of a demonstration plant in 2 to 3 years if research regarding TES system design is undertaken in a timely manner. (LCL)

  3. Effect of non-thermal air atmospheric pressure plasma jet treatment on gingival wound healing

    Non-thermal atmospheric pressure plasmas have been applied in the biomedical field for the improvement of various cellular activities. In dentistry, the healing of gingival soft tissue plays an important role in health and aesthetic outcomes. While the biomedical application of plasma has been thoroughly studied in dentistry, a detailed investigation of plasma-mediated human gingival fibroblast (HGF) migration for wound healing and its underlying biological mechanism is still pending. Therefore, the aim of this study is to apply a non-thermal air atmospheric pressure plasma jet (NTAAPPJ) to HGF to measure the migration and to reveal the underlying biological mechanisms involved in the migration. After the characterization of NTAAPPJ by optical emission spectroscopy, the adherent HGF was treated with NTAAPPJ or air with a different flow rate. Cell viability, lipid peroxidation, migration, intracellular reactive oxygen species (ROS), and the expression of migration-related genes (EGFR, PAK1, and MAPK3) were investigated. The level of statistical significance was set at 0.05. NTAAPPJ and air treatment with a flow rate of 250–1000 standard cubic centimetres per minute (sccm) for up to 30 s did not induce significant decreases in cell viability or membrane damage. A significant increase in the migration of mitomycin C-treated HGF was observed after 30 s of NTAAPPJ treatment compared to 30 s air-only treatment, which was induced by high levels of intracellular reactive oxygen species (ROS). An increase in migration-related gene expression and EGFR activation was observed following NTAAPPJ treatment in an air flow rate-dependent manner. This is the first report that NTAAPPJ treatment induces an increase in HGF migration without changing cell viability or causing membrane damage. HGF migration was related to an increase in intracellular ROS, changes in the expression of three of the migration-related genes (EGFR, PAK1, and MAPK1), and EGFR activation. Therefore

  4. Effect of non-thermal air atmospheric pressure plasma jet treatment on gingival wound healing

    Lee, Jung-Hwan; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2016-02-01

    Non-thermal atmospheric pressure plasmas have been applied in the biomedical field for the improvement of various cellular activities. In dentistry, the healing of gingival soft tissue plays an important role in health and aesthetic outcomes. While the biomedical application of plasma has been thoroughly studied in dentistry, a detailed investigation of plasma-mediated human gingival fibroblast (HGF) migration for wound healing and its underlying biological mechanism is still pending. Therefore, the aim of this study is to apply a non-thermal air atmospheric pressure plasma jet (NTAAPPJ) to HGF to measure the migration and to reveal the underlying biological mechanisms involved in the migration. After the characterization of NTAAPPJ by optical emission spectroscopy, the adherent HGF was treated with NTAAPPJ or air with a different flow rate. Cell viability, lipid peroxidation, migration, intracellular reactive oxygen species (ROS), and the expression of migration-related genes (EGFR, PAK1, and MAPK3) were investigated. The level of statistical significance was set at 0.05. NTAAPPJ and air treatment with a flow rate of 250–1000 standard cubic centimetres per minute (sccm) for up to 30 s did not induce significant decreases in cell viability or membrane damage. A significant increase in the migration of mitomycin C-treated HGF was observed after 30 s of NTAAPPJ treatment compared to 30 s air-only treatment, which was induced by high levels of intracellular reactive oxygen species (ROS). An increase in migration-related gene expression and EGFR activation was observed following NTAAPPJ treatment in an air flow rate-dependent manner. This is the first report that NTAAPPJ treatment induces an increase in HGF migration without changing cell viability or causing membrane damage. HGF migration was related to an increase in intracellular ROS, changes in the expression of three of the migration-related genes (EGFR, PAK1, and MAPK1), and EGFR activation. Therefore

  5. Identification of emitted air pollutants from natural rubber processing via thermal desorbed-gas chromatography

    Natural rubber processing has been identified as one of the major sources of organic pollution in Malaysia. Emissions of malodorous vapors which mainly consist of volatile organic compounds (VOC) resulted from the breakdown of non-rubber constituent during drying of block rubbers has contributed to air pollution. The malodour pollution is currently being controlled by treatment using water scrubber systems as adopted by most rubber processing factories. Performance of water scrubbers is monitored by analyzing vapors before and after treatment using a dynamic olfactometer in a form of odor concentration unit. Most water scrubbers installed are able achieve 75-80 % removal of malodour. However, previous research carried out in identifying and quantifying air pollutants using gas chromatographic technique with calibration against limited volatile fatty acids (VFAs) revealed that 90 % removal of VFAs which is not in agreement with the olfactometric results. This paper describes a new technique to characterize air pollutants using a combination of thermal desorbed and gas chromatography. This set up broadens detection of VFAs and also mercaptans. Present results showed more VFAs and some mercaptans were being detected in the emission as compared to the previous technique using a regular gas chromatography. It was shown that the malodour was contributed by more VOC as reflected from the olfactometric results. The new characterization technique provides new technical information to develop more efficient treatment systems to treat malodour pollution from the rubber processing industry. (author)

  6. Air-Water Gas Exchange in Wetland Water Columns Due To Wind and Thermal Convection

    Poindexter, C.; Variano, E. A.

    2011-12-01

    The goal of this work is to provide a parameterization of the air-water gas transfer rate in wetlands, and do so in terms of easily measured environmental variables. This parameterization is intended to support biogeochemical modeling in wetlands by providing an interfacial flux of key importance. Our approach uses laboratory experiments describe the oxygen transfer across an air-water interface in a model wetland. The oxygen transfer is sensitive to the externally imposed wind, vegetation characteristics, and vertical thermal convection. We vary these systematically, determining the gas transfer (or "piston") velocity that describes interfacial gas flux. We measure velocity vector fields near the air-water interface using particle image velocimetry, and use these measurements to help explain the mechanisms behind the measured trends in oxygen transfer. The explanatory power of these measurements includes the relationship between plant geometry and surface divergence. We explore the potential impact of our results on wetland modeling and management, for issues such as carbon sequestration and methane emission.

  7. Design of a MEMS piezoresistive differential pressure sensor with small thermal hysteresis for air data modules

    Song, Jin Woo; Lee, Jang-Sub; An, Jun-Eon; Park, Chan Gook

    2015-06-01

    The design, fabrication, and evaluation results of a MEMS piezoresistive differential pressure sensor fabricated by the dry etching process are described in this paper. The proposed sensor is designed to have optimal performances in mid-pressure range from 0 psi to 20 psi suitable for a precision air data module. The piezoresistors with a Wheatstone bridge structure are implanted where the thermal effects are minimized subject to sustainment of the sensitivity. The rectangular-shaped silicon diaphragm is adopted and its dimension is analyzed for improving pressure sensitivity and linearity. The bridge resistors are driven by constant current to compensate temperature effects on sensitivity. The designed differential pressure sensor is fabricated by using MEMS dry etching techniques, and the fabricated sensing element is attached and packaged in a Kovar package in consideration of leakage and temperature hysteresis. The implemented sensors are tested and evaluated as well. The evaluation results show the static RSS (root sum square) accuracy including nonlinearity, non-repeatability, and pressure hysteresis before temperature compensation is about 0.09%, and the total error band which includes the RSS accuracy, the thermal hysteresis, and other thermal effects is about 0.11%, which confirm the validity of the proposed design process.

  8. Total human exposure and indoor air quality: An automated bibliography (BLIS) with summary abstracts. Volume 2. Final report, January 1987-December 1989

    The Bibliographical Literature Information System (BLIS) is a computer database that provides a comprehensive review of available literature on total human exposure to environmental pollution. Brief abstracts (often condensed versions of the original abstract) are included; if the original document had no abstract, one was prepared. Unpublished draft reports are listed, as well as final reports of the U.S. Government and other countries, reports by governmental research contractors, journal articles, and other publications on exposure models field data, and newly emerging research methodologies. Emphasis is placed on those field studies measuring all the concentrations to which people may be exposed, including indoors, outdoors, and in-transit

  9. Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

    Beumer, Ronald J.

    1989-01-01

    The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

  10. Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode

    Fang, Guiyin; Hu, Hainan; Liu, Xu [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2010-09-15

    An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

  11. Effect of air ingress on the energy performance of coal fired thermal power plants

    Ingress of air in boilers leads to drops in energy efficiency. This paper presents the effects of air ingress in the combustion zone, post-combustion zone and air pre-heater (APH) on the energy efficiency and loading capacity of a coal fired thermal power plant operating on fuel with high ash (35-45%). The optimal O2 in the flue gas for a pulverized coal fired system is 3.5% (corresponding to 20% excess air). The operating values are in the range of 4.2-6.0% in membrane type boilers and up to 10% in refractory type boilers (after sustained periods of operation). The leakage rate of boilers (up to the entrance of the APH) is designed at 0.2% while the average operating values are 7.25% for membrane type enclosures and 33.61% for refractory enclosures. The leakage rate of the APH is designed at 5.0% while the operating values range from 13.66% to 20.13% for rotary and tubular APHs. When the O2 in the combustion zone varies from 3.5% to 8.0%, efficiency drops of 2.0% points are experienced in the boiler and turbine separately, and the gross overall efficiency drop is ∼3.0% points. The units do not experience any capacity drop up to an O2 in the flue gas of 6.0% before the APH. At an O2 in the flue gas (before APH) of 7.2%, a mild limitation on the unit capacity of around 2-3% is experienced. When O2 in the flue gas (before APH) reaches a level of 9.0%, 20% capacity drop of the unit is experienced due to which the plant load cannot be raised higher than 80%. Beyond the level of 9.0% (rare occurrence), the unit is quite difficult to operate and has to be taken off for overhaul

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

    Major cities in South-central Chile suffer high levels of particulate matter PM10 and PM2.5 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 PM2.5 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

  13. Use of local convective and radiant cooling at warm environment: effect on thermal comfort and perceived air quality

    Melikov, Arsen Krikor; Duszyk, Marcin; Krejcirikova, Barbora;

    2012-01-01

    The effect of four local cooling devices (convective, radiant and combined) on thermal comfort and perceived air quality reported by 24 subjects at 28 ˚C and 50% RH was studied. The devices studied were: (1) desk cooling fan, (2) personalized ventilation providing clean air, (3) two radiant panels...... comfort compared to without cooling. The acceptability of the thermal environment was similar for all cooling devices. The acceptability of air movement and PAQ increased when the local cooling methods were used. The best results were achieved with personalized ventilation and cooling fan. The improvement...... and (4) two radiant panels with one panel equipped with small fans. A reference condition without cooling was tested as well. The response of the subjects to the exposed conditions was collected by computerized questionnaires. The cooling devices significantly (p<0,05) improved subjects’ thermal...

  14. Impact of kiln thermal energy demand and false air on cement kiln flue gas CO2 capture

    Arachchige, Udara S.P.R.; Kawan, Dinesh; Tokheim, Lars-Andre [Telemark University College, Porsgrunn (Norway); Melaaen, Morten C. [Telemark University College, Porsgrunn (Norway); (Tel-Tek, Porsgrunn (Norway)

    2013-07-01

    The present study is focused on the effect of the specific thermal energy demand and the false air factor on carbon capture applied to cement kiln exhaust gases. The carbon capture process model was developed and implemented in Aspen Plus. The model was developed for flue gases from a typical cement clinker manufacturing plant. The specific thermal energy demand as well as the false air factor of the kiln system were varied in order to determine the effect on CO2 capture plant performance, such as the solvent regeneration energy demand. In general, an increase in the mentioned kiln system factors increases the regeneration energy demand. The reboiler energy demand is calculated as 3270, 3428 and 3589 kJ/kg clinker for a specific thermal energy of 3000, 3400 and 3800 kJ/kg clinker, respectively. Setting the false air factor to 25, 50 or 70% gives a reboiler energy demand of 3428, 3476, 3568 kJ/kg clinker, respectively.

  15. Demonstration of the Performance of an Air-Type Photovoltaic Thermal (PVT System Coupled with a Heat-Recovery Ventilator

    Jin-Hee Kim

    2016-09-01

    Full Text Available A heat-recovery ventilator (HRV effectively conducts ventilation by recovering waste heat from indoors to outdoors during heating periods. However, dew condensation associated with the HRV system may arise due to the difference between the indoor temperature and the very low outdoor temperature in winter, and this can decrease the heat exchange efficiency. These problems can be solved by the pre-heating of the incoming air, but additional energy is required when pursuing such a strategy. On the other hand, an air-type photovoltaic thermal (PVT system produces electricity and thermal energy simultaneously using air as the heat transfer medium. Moreover, the heated air from the air-type PVT system can be connected to the HRV to pre-heat the supply air instead of taking in the cold outdoor air. Thus, the ventilation efficiency can be improved and the problems arising during the heating period can be resolved. Consequentially, the heating energy required in a building can be reduced, with additional electricity acquired as well. In this paper, the performance of an air-type PVT system coupled with an HRV is assessed. To do this, air-type PVT collectors operating at 1 kWp were installed in an experimental house and coupled to an HRV system. Thermal performance and heating energy required during the winter season were analyzed experimentally. Furthermore, the electrical performances of the air-type PVT system with and without ventilation at the back side of the PV during the summer season were analyzed.

  16. Modeling of Thermal Arcs in Molded Case Circuit Breakers in Air

    Breden, Doug; Mahadevan, Shankar; Raja, Laxminarayan

    2015-09-01

    A general-purpose thermal plasma simulation tool (VizArc) was utilized to model a circuit breaker in atmospheric pressure air. The molded case circuit breaker (MCCB) circuit breaker works by separating two metal contacts when the breaking current is exceeded generating an arc. The self-consistent Lorentz force generated by the current pushes the arc into an array of splitter plates which quench the arc and break the circuit. The arc channel is modeled by coupling the electromagnetic equations with flow governing equations to model a multi-species, single-temperature quasi neutral arc plasma. Conjugate heat transfer to the metal splitter plates and vapor ablation into the gas are included in the model. The opening action of the moving contact armature is simulated dynamically in the simulation. The set of all governing equations and their implementation in the model will be discussed, and then the simulations of the MCCB circuit breaker using the model will be presented.

  17. Ignition phase and steady-state structures of a non-thermal air plasma

    An AC-driven, non-thermal, atmospheric pressure air plasma is generated within the gap separating a disc-shaped metal electrode and a water electrode. The ignition phase and the steady-state are studied by a high-speed CCD camera. It is found that the plasma always initiates at the surface of the water electrode. The plasma exhibits different structures depending on the polarity of the water electrode: when the water electrode plays the role of cathode, a relatively wide but visibly dim plasma column is generated. At the maximum driving voltage, the gas temperature is between 800 and 900 K, and the peak current is 67 mA; when the water electrode is anode, the plasma column narrows but increases its light emission. The gas temperature in this case is measured to be in the 1400-1500 K range, and the peak current is 81 mA

  18. Thermal design of a modern, air-conditioned, single-floor, solar-powered desert house

    Serag-Eldin, M. A.

    2011-12-01

    The paper presents a thermal analysis of a single-floor, solar-powered desert house. The house is air-conditioned and provides all modern comforts and facilities. Electrical power, which drives the entire energy system, is generated by roof-mounted photovoltaic modules. The modules are fixed on special cradles which fold at night to expose the roof to the night sky, thereby enhancing night-time cooling, which is substantial in the desert environment. A detailed dynamic heat transfer analysis is conducted for the building envelope, coupled with a solar radiation model. Application to a typical Middle-Eastern desert site reveals that indeed such a design is feasible with present-day technology; and should be even more attractive with future advances in technology. © 2011 Copyright Taylor and Francis Group, LLC.

  19. Thermal System Analysis and Optimization of Large-Scale Compressed Air Energy Storage (CAES

    Zhongguang Fu

    2015-08-01

    Full Text Available As an important solution to issues regarding peak load and renewable energy resources on grids, large-scale compressed air energy storage (CAES power generation technology has recently become a popular research topic in the area of large-scale industrial energy storage. At present, the combination of high-expansion ratio turbines with advanced gas turbine technology is an important breakthrough in energy storage technology. In this study, a new gas turbine power generation system is coupled with current CAES technology. Moreover, a thermodynamic cycle system is optimized by calculating for the parameters of a thermodynamic system. Results show that the thermal efficiency of the new system increases by at least 5% over that of the existing system.

  20. Kinetics of the Thermal Decomposition of Magnesium Salicylate Powder in Air

    2006-01-01

    Simultaneous thermogravimetry-differential thermal analysis (TG-DTA) was used to study the kinetics and the degradation of magnesium salicylate(C14H10MgO6) in air. The results show that the decomposition proceeds through two steps. The kinetics of the first decomposition step was studied. The activation energies were calculated by using the Friedman and Flynn Wall Ozawa (FWO) methods, and the most probable kinetic model function was estimated using the multiple linear regression method. The values of the correlated kinetic parameters for the first decomposition step are E= 152.97 kJ/mol, lg(A/S-1) = 10. 78, f(α) = (1 -α)n(1 + Kcatα) , n =0.691, and Kcat =1.3048.

  1. Evaluation Framework and Analyses for Thermal Energy Storage Integrated with Packaged Air Conditioning

    Kung, F.; Deru, M.; Bonnema, E.

    2013-10-01

    Few third-party guidance documents or tools are available for evaluating thermal energy storage (TES) integrated with packaged air conditioning (AC), as this type of TES is relatively new compared to TES integrated with chillers or hot water systems. To address this gap, researchers at the National Renewable Energy Laboratory conducted a project to improve the ability of potential technology adopters to evaluate TES technologies. Major project outcomes included: development of an evaluation framework to describe key metrics, methodologies, and issues to consider when assessing the performance of TES systems integrated with packaged AC; application of multiple concepts from the evaluation framework to analyze performance data from four demonstration sites; and production of a new simulation capability that enables modeling of TES integrated with packaged AC in EnergyPlus. This report includes the evaluation framework and analysis results from the project.

  2. Selection of Weather Parameters for Air-Conditioning System Design for Buildings with Long Thermal Lag

    GE Lian-feng; LEI Ming; CHEN You-ming

    2009-01-01

    Two building factors-a longer thermal lag of more than one hour for building envelops and a lag of indoor radiation to convert into cooling load-have impact on the instantaneous heat input and instantaneous cooling load.So the two factors should be taken into account when selecting the weather parameters for air-con-ditioning system design.This paper developed a new statistic method for the rational selection of coincident solar irradiance,dry-bulb and wet-bulb temperatures.The method was applied to historic weather records of 25 years in Hong Kong to generate coincident design weather data.And the results show that traditional design solar irra-diance,dry-bulb and wet-bulb temperatures may be significantly overestimated in many conditions,and the de-sign weather data for the three different constructions is not kept constant.

  3. Outdoor overall performance of a novel air-gap-lens-walled compound parabolic concentrator (ALCPC) incorporated with photovoltaic/thermal system

    Highlights: • A prototype of an ALCPC-PV/T system was designed and set up. • Good optical agreements were observed between simulation and experiment. • The effects of the temperature on the electrical characteristics were discussed. • The thermal performance for circulating cooling was analyzed. • The system efficiency was calculated to present the overall performance. - Abstract: A novel air-gap-lens-walled compound parabolic concentrator incorporated with photovoltaic/thermal system (ALCPC-PV/T) was proposed. The optical, electrical and thermal performances of the ALCPC-PV/T under the outdoor condition were analyzed for building integrated concentrating photovoltaic/thermal application. The simulation and experiment were carried out to reveal the optical characteristics of ALCPC-PV/T on two typical days. The experiment results verified the optical simulation results that the ALCPC-PV/T system had a half acceptance angle of 35° and an average optical efficiency of 83.0% within the half acceptance angle for direct incidence. Furthermore, the average optical efficiencies on the two typical days were all above 60% under the actual outdoor condition considering direct and diffuse solar radiation. Details of electrical characteristics affected by the temperature of circulating cooling water were also displayed. The electrical and thermal efficiencies of the ALCPC-PV/T system during the test were 6.0% and 35.0% respectively with the final water temperature of 70 °C. In addition, the fitted results indicated that under the zero reduced temperature condition, the thermal efficiency of the ALCPC PV/T system was 52.0%, and the corresponding electrical efficiency was 6.6%

  4. Novel Air Flow Meter for an Automobile Engine Using a Si Sensor with Porous Si Thermal Isolation

    Androula G. Nassiopoulou; Panagiotis Sarafis; Emmanouel Hourdakis

    2012-01-01

    An air flow meter for measuring the intake air of an automobile engine is presented. It is based on a miniaturized silicon thermal mass flow sensor using a thick porous Si (Po-Si) layer for local thermal isolation from the Si substrate, on which the sensor active elements are integrated. The sensor is mounted on one side of a printed circuit board (PCB), on the other side of which the readout and control electronics of the meter are mounted. The PCB is fixed on a housing containing a semi-cyl...

  5. Thermal comfort in air-conditioned buildings in hot and humid climates--why are we not getting it right?

    Sekhar, S C

    2016-02-01

    While there are plenty of anecdotal experiences of overcooled buildings in summer, evidence from field studies suggests that there is indeed an issue of overcooling in tropical buildings. The findings suggest that overcooled buildings are not a consequence of occupant preference but more like an outcome of the HVAC system design and operation. Occupants' adaptation in overcooled indoor environments through additional clothing cannot be regarded as an effective mitigating strategy for cold thermal discomfort. In the last two decades or so, several field studies and field environmental chamber studies in the tropics provided evidence for occupants' preference for a warmer temperature with adaptation methods such as elevated air speeds. It is important to bear in mind that indoor humidity levels are not compromised as they could have an impact on the inhaled air condition that could eventually affect perceived air quality. This review article has attempted to track significant developments in our understanding of the thermal comfort issues in air-conditioned office and educational buildings in hot and humid climates in the last 25 years, primarily on occupant preference for thermal comfort in such climates. The issue of overcooled buildings, by design intent or otherwise, is discussed in some detail. Finally, the article has explored some viable adaptive thermal comfort options that show considerable promise for not only improving thermal comfort in tropical buildings but are also energy efficient and could be seen as sustainable solutions. PMID:25626476

  6. Novel mass air flow meter for automobile industry based on thermal flow microsensor. I. Analytical model and microsensor

    Sazhin, O.

    2013-01-01

    An analytical model of the thermal flow sensor has been developed. The results of analytical model application are utilized to develop a thermal flow microsensor with optimal functional characteristics. The technology to manufacture the microsensor is described. A prototype of the microsensor suitable to be used in the mass air flow meter has been designed. The basic characteristics of the microsensor are presented. © 2013 Elsevier Ltd.

  7. Theoretical study of a hot air collector consisting of a solar greenhouse and thermal storage: application to drying

    N' Dongo, M.M.; Zeghmati, B.; Mammou, M.; Daguenet, M. (Perpignan Univ., 66 (France). Lab. de Thermodynamique et Energetique)

    1993-04-01

    In this paper, we present a numerical study of a system consisting of a solar greenhouse and thermal storage. The thermal storage consists of insulated pipes which are buried and arranged in parallel inside the greenhouse. This system is used as a solar collector for a fish dryer which is placed near the greenhouse. The numerical results show that the best configuration is to operate the system with dynamic storage in the ground and to recycle the air through the dryer. (Author)

  8. Experimental study of an air-cooled thermal management system for high capacity lithium-titanate batteries

    Giuliano, Michael R.; Prasad, Ajay K.; Advani, Suresh G.

    2012-10-01

    Lithium-titanate batteries have become an attractive option for battery electric vehicles and hybrid electric vehicles. In order to maintain safe operating temperatures, these batteries must be actively cooled during operation. Liquid-cooled systems typically employed for this purpose are inefficient due to the parasitic power consumed by the on-board chiller unit and the coolant pump. A more efficient option would be to circulate ambient air through the battery bank and directly reject the heat to the ambient. We designed and fabricated such an air-cooled thermal management system employing metal-foam based heat exchanger plates for sufficient heat removal capacity. Experiments were conducted with Altairnano's 50 Ah cells over a range of charge-discharge cycle currents at two air flow rates. It was found that an airflow of 1100 mls-1 per cell restricts the temperature rise of the coolant air to less than 10 °C over ambient even for 200 A charge-discharge cycles. Furthermore, it was shown that the power required to drive the air through the heat exchanger was less than a conventional liquid-cooled thermal management system. The results indicate that air-cooled systems can be an effective and efficient method for the thermal management of automotive battery packs.

  9. Characterization of Air-Based Photovoltaic Thermal Panels with Bifacial Solar Cells

    P. Ooshaksaraei

    2013-01-01

    Full Text Available Photovoltaic (PV panels account for a majority of the cost of photovoltaic thermal (PVT panels. Bifacial silicon solar panels are attractive for PVT panels because of their potential to enhance electrical power generation from the same silicon wafer compared with conventional monofacial solar panels. This paper examines the performance of air-based bifacial PVT panels with regard to the first and second laws of thermodynamics. Four air-based bifacial PVT panels were designed. The maximum efficiencies of 45% to 63% were observed for the double-path-parallel bifacial PVT panel based on the first law of thermodynamics. Single-path bifacial PVT panel represents the highest exergy efficiency (10%. Double-path-parallel bifacial PVT panel is the second preferred design as it generates up to 20% additional total energy compared with the single-path panel. However, the daily average exergy efficiency of a double-path-parallel panel is 0.35% lower than that of a single-path panel.

  10. A new concept of high flow rate non-thermal plasma reactor for air treatment

    Goujard, V.; Tatibouet, J.M. [Univ. de Poitiers, Poitiers (France). Centre national de la recherche scientifique, Laboratoire de Catalyse en Chimie Organique

    2010-07-01

    Although several non-thermal plasma reactors have been tested for air treatment at the laboratory scale, up-scaling to pilot or industrial scale remains a challenge because several parameters must be considered, such as hydrodynamic behaviour, maximum voltage in an industrial environment, and maintenance of the system. This paper presented a newly developed reactor which consists to a DBD plasma generated on individual supports that could be directly inserted in gas pipes where air flow must be treated. Elimination of 40 percent of 15 ppm of propene was obtained with a energy density as low as 10 J/L. The propene conversion increased when a manganese oxide based catalyst was used because the ozone produced by the plasma was used as an as an oxidant. A simple model of the plasma-catalyst reactor behaviour showed that more than 90 percent of propene conversion can be expected for an input energy density of 10 J/L and residual ozone concentration less than 100 ppb.

  11. A dynamic thermal model for design and control of an 800-element open-air radio telescope

    Bremer, Michael; Greve, Albert

    2011-09-01

    In earlier work we have described the thermal modelling for design and control of a fully insulated, and sometimes ventilated, high precision radio telescope. For such an insulated telescope the modelling of the time-variable dynamic influence of the thermal environment (air, sky and ground radiation, insolation) is relatively simple. The modelling becomes however quite complex for an open-air radio telescope where each individual member of the reflector backup structure (BUS) and the support structure (fork or yoke) is exposed under a different and time-dependent aspect angle to the thermal environment, which applies in particular to solar radiation. We present a time-dependent 800-element thermal model of an open-air telescope. Using the IRAM 30-m radio telescope as the basic mechanical structure, we explain how the temperature induced, real-time pointing and reflector surface deformations can be derived when using as input the day of the year, the thermal environment, and the geographic position of the telescope and its changing pointing direction. Thermal modelling and results similar to those reported here can be used for radio telescope design and real-time control of pointing and surface adjustment of a telescope with active panels.

  12. Experimental investigation of an innovative thermochemical process operating with a hydrate salt and moist air for thermal storage of solar energy: Global performance

    Highlights: • A large scale thermochemical storage system working with moist air is experimented. • High energy density (203 kW h/m3) and storage capacity (105 kW h) have been obtained. • Hydration specific powers between 0.75 and 2 W/kg have been reached. • The ways to control the storage system have been deeply investigated. • Two important parameters (equilibrium drop and mass flowrate) have been identified. - Abstract: This paper investigates an innovative open thermochemical system dedicated to high density and long term (seasonal) storage purposes. It involves a hydrate/water reactive pair and operates with moist air. This work focuses on the design of and experimentation with a large scale prototype using SrBr2/H2O as a reactive pair (400 kg of hydrated salt, 105 kW h of storage capacity and a reactor energy density of 203 kW h/m3). Promising conclusions have been obtained regarding the feasibility and performance of such a storage process. Hydration specific powers from 0.75 to 2 W/kg have been reached for a bed salt energy density of 388 kW h/m3. Moreover, two important parameters that control the storage system have been identified and investigated: the equilibrium drop and the mass flow rate of moist air. Both have a strong influence on the reaction kinetics and therefore on the reactor’s thermal power

  13. The influence of gas radiation on the thermal behavior of a 2D axisymmetric turbulent non-premixed methane–air flame

    Highlights: • The study evaluates the importance of thermal radiation in a methane–air flame. • The radiative properties are treated with the WSGG based on HITEMP 2010. • The turbulence–radiation interaction (TRI) is based on a RANS approach. • Radiation strongly affected the temperature field but not the chemical composition. • Neglecting TRI led to a lower estimate of the radiation heat transfer. - Abstract: This paper presents a study of the effect of thermal radiation in the simulation of a turbulent, non-premixed methane–air flame. In such a problem, two aspects need to be considered for a precise evaluation of the thermal radiation: the turbulence–radiation interactions (TRI), and the local variation of the radiative properties of the participating species, which are treated here with the weighted-sum-of-gray-gases (WSGG) model based on newly obtained correlations from HITEMP2010 database. The chemical reactions rates were considered as the minimum values between the Arrhenius and Eddy Break-Up rates. A two-step global reaction mechanism was used, while the turbulence modeling was considered via standard k–ε model. The source terms of the energy equation consisted of the heat generated in the chemical reaction rates as well as in the radiation exchanges. The discrete ordinates method (DOM) was employed to solve the radiative transfer equation (RTE), including the TRI. Comparisons of simulations with/without radiation (which in turn was solved with/without TRI) demonstrated that the temperature, the radiative heat source, and the wall heat flux were importantly affected by thermal radiation, while the influence on species concentrations proved to be negligible. Inclusion of thermal radiation led to results that were closer to experimental data available in the literature for the same test case considered in this paper. Inclusion of TRI improved the agreement, although in a smaller degree. The main influence of TRI was mainly on global

  14. Energy efficient hybrid nanocomposite-based cool thermal storage air conditioning system for sustainable buildings

    The quest towards energy conservative building design is increasingly popular in recent years, which has triggered greater interests in developing energy efficient systems for space cooling in buildings. In this work, energy efficient silver–titania HiTES (hybrid nanocomposites-based cool thermal energy storage) system combined with building A/C (air conditioning) system was experimentally investigated for summer and winter design conditions. HiNPCM (hybrid nanocomposite particles embedded PCM) used as the heat storage material has exhibited 7.3–58.4% of improved thermal conductivity than at its purest state. The complete freezing time for HiNPCM was reduced by 15% which was attributed to its improved thermophysical characteristics. Experimental results suggest that the effective energy redistribution capability of HiTES system has contributed for reduction in the chiller nominal cooling capacity by 46.3% and 39.6% respectively, under part load and on-peak load operating conditions. The HiTES A/C system achieved 27.3% and 32.5% of on-peak energy savings potential in summer and winter respectively compared to the conventional A/C system. For the same operating conditions, this system yield 8.3%, 12.2% and 7.2% and 10.2% of per day average and yearly energy conservation respectively. This system can be applied for year-round space conditioning application without sacrificing energy efficiency in buildings. - Highlights: • Energy storage is acquired by HiTES (hybrid nanocomposites-thermal storage) system. • Thermal conductivity of HiNPCM (hybrid nanocomposites-PCM) was improved by 58.4%. • Freezing time of HiNPCM was reduced by 15% that enabled improved energy efficiency. • Chiller nominal capacity was reduced by 46.3% and 39.6% in on-peak and part load respectively. • HiTES A/C system achieved appreciable energy savings in the range of 8.3–12.2%

  15. Durability of zirconia thermal-barrier ceramic coatings on air-cooled turbine blades in cyclic jet engine operation

    Liebert, C. H.; Jacobs, R. E.; Stecura, S.; Morse, C. R.

    1976-01-01

    Thermal barrier ceramic coatings of stabilized zirconia over a bond coat of Ni Cr Al Y were tested for durability on air cooled turbine rotor blades in a research turbojet engine. Zirconia stabilized with either yttria, magnesia, or calcia was investigated. On the basis of durability and processing cost, the yttria stabilized zirconia was considered the best of the three coatings investigated.

  16. Study of mixed radiative thermal mass transfer in the case of spherical liquide particle evaporation in a high temperature thermal air plasma

    Radiative transfer in a semi-transparent non-isothermal medium with spherical configuration has been studied. Limit conditions have been detailed, among which the semi-transparent inner sphere case is a new case. Enthalpy and matter transfer equations related to these different cases have been established. An adimensional study of local conservation laws allowed to reveal a parameter set characteristic of radiation coupled phenomena thermal conduction, convection, diffusion. Transfer equations in the case of evaporation of a liquid spherical particle in an air thermal plasma have been simplified. An analytical solution for matter transfer is proposed. Numerical solution of radiative problems and matter transfer has been realized

  17. Thermal profile analysis of Doubly-Fed induction generator based wind power converter with air and liquid cooling methods

    Zhou, Dao; Blaabjerg, Frede; Lau, Mogens; Tonnes, Michael

    cooling seen from a thermal profile assessment point of view. Firstly, an analytical approach from loss profile to thermal profile for the power semiconductor is proposed and verified in a 2 MW Doubly-Fed Induction Generator (DFIG) based wind turbine system. Then, the typical air cooling and liquid......Today, wind power generation system keeps on moving from onshore to offshore and also upscaling in size. As the lifetime of the wind power converter is prolonged to 20–25 years, this paper will investigate and compare different cooling methods for power modules — the air cooling and the liquid...... cooling in wind power converter are analyzed and compared in terms of the mean junction temperature and the junction temperature fluctuation. It is concluded that the liquid cooling approach has a similar junction temperature fluctuation but gives a lower mean junction temperature than the air cooling...

  18. Study of the thermal performance and air-flow features of a solar air heater with evacuated tubes

    Papanicolaou, E.; Belessiotis, V. [Solar and other Energy Systems Lab., ' ' Democritos' ' National Center for Scientific Research, Aghia Paraskevi, Attiki (Greece); Li, X.; Wang, Z. [Solar Energy Lab., Inst. of Electrical Engineering, Chinese Academy of Sciences, BJ (China)

    2008-07-01

    In the present paper, aspects related to the energy performance of a solar air heater comprising an array of dual-glass evacuated tubes using air as the working fluid, are investigated. Design parameters affecting the performance of the heater are the air flow-rate, the diameter and length ratios (insert tube/inner glass tube), the latter defining the discharge location, the flow configuration (series or parallel connection of tubes) etc. Numerical simulations of flow and heat transfer within a single tube are performed for a selected configuration, giving insight into details of the flow and temperature fields, which are valuable in the pursuit of the optimal design of the geometric and physical parameters. Besides, efficiency curves for the air heater are obtained from experimental measurements at both cooperating laboratories. (orig.)

  19. AN INVESTIGATION OF THE EFFECTS OF AIR VELOCITY AND MOVEMENT ON THE THERMAL COMFORT INSIDE AN AUTOMOBILE

    Ömer KAYNAKLI

    2003-03-01

    Full Text Available In this study, heat loss from various parts of human body, generated sweat mass and skin wetness depends on this are determined and their effect on thermal comfort are investigated. In the model human body is examined as divided into 16 parts and heat and mass transfer from each parts is simulated, as air flow velocity over the surface and thermal and evaporation resistance of clothing are accounted for the model. After checking the validity of the model (in comparison with results as an experimental study heat transfer coefficients, sensible and latent heat loss, skin wetness and variations of predicted percentage of dissatisfied (PPD are investigated for various air velocities, air temperatures and clothing groups. It is included that, average skin wetness decreases with increasing air velocity and sensible and latent heat losses increase due to the increase in heat transfer coefficient with increasing air velocity. However increase in sensible heat loss is more than latent heat loss. The most sensitive parameter to the air velocity is PPD.

  20. Thermal Performance Evaluation of the 200 kWth Sol Air Volumetric Solar Receiver

    The goal of the Solair project is the design and test of a fully modular, high efficient and durable open volumetric high-flux receiver, which can be easily and safely operated at mean air outlet temperatures of up to 800 degree centigree. The project was thought in two phases, in the first one an advanced 200 kW HitRec receiver called Solair 200 was designed and tested. The Solair 200 was built like one single receiver module (subassembly), to test the thermal performance of the receiver as well as the receiver module behavior. Out of a set of these receiver modules have been developed to assemble the 3 MWth receiver in the second phase of the project. This report describes the used procedure or methodology for data processing for thermal performance evaluation purposes and the data processing results for the first phase of the project. Test campaign started in March 2002 and produced fifty data sheets (each corresponding to a test day) and ended in February 2003. During the test phase three absorber material types (or configurations) have been tested during the test campaign. The data processing and evaluation results show that performance goals for the receiver have been fluffy accomplished: Temperatures of more than 800 degree centigree were achieved for the first two configurations in five test days. For the two absorber configurations for which incident solar power was measured the estimated efficiency at 700 degree centigree was 81 (±6)% for configuration 1 and 83 (±6) % for configuration 2 of the absorber. (Author) 20 refs

  1. Thermodynamic study of the effects of ambient air conditions on the thermal performance characteristics of a closed wet cooling tower

    A thermodynamic model was developed and used to assess the sensitivity of thermal performance characteristics of a closed wet cooling tower to inlet air conditions. In the present study, three cases of different ambient conditions are considered: In the first case, the average mid-winter and mid-summer conditions as well as the extreme case of high temperature and relative humidity, in Athens (Greece) during summer are considered according to the Greek Regulation for Buildings Energy Performance. In the second case, the varied inlet air relative humidity while the inlet air dry bulb temperature remains constant were taken into account. In the last case, the effects on cooling tower thermal behaviour when the inlet air wet bulb temperature remains constant were examined. The proposed model is capable of predicting the variation of air thermodynamic properties, sprayed water and serpentine water temperature inside the closed wet cooling tower along its height. The reliability of simulations was tested against experimental data, which were obtained from literature. Thus, the proposed model could be used for the design of industrial and domestic applications of conventional air-conditioning systems as well as for sorption cooling systems with solid and liquid desiccants where closed wet cooling towers are used for precooling the liquid solutions. The most important result of this theoretical investigation is that the highest fall of serpentine water temperature and losses of sprayed water are observed for the lowest value of inlet wet bulb temperature. Hence, the thermal effectiveness, which is associated with the temperature reduction of serpentine water as well as the operational cost, which is related to the sprayed water loss due to evaporation, of a closed wet cooling tower depend predominantly on the degree of saturation of inlet air.

  2. EBS Radionuclide Transport Abstraction

    The purpose of this work is to develop the Engineered Barrier System (EBS) radionuclide transport abstraction model, as directed by a written development plan (CRWMS M and O 1999a). This abstraction is the conceptual model that will be used to determine the rate of release of radionuclides from the EBS to the unsaturated zone (UZ) in the total system performance assessment-license application (TSPA-LA). In particular, this model will be used to quantify the time-dependent radionuclide releases from a failed waste package (WP) and their subsequent transport through the EBS to the emplacement drift wall/UZ interface. The development of this conceptual model will allow Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department to provide a more detailed and complete EBS flow and transport abstraction. The results from this conceptual model will allow PA0 to address portions of the key technical issues (KTIs) presented in three NRC Issue Resolution Status Reports (IRSRs): (1) the Evolution of the Near-Field Environment (ENFE), Revision 2 (NRC 1999a), (2) the Container Life and Source Term (CLST), Revision 2 (NRC 1999b), and (3) the Thermal Effects on Flow (TEF), Revision 1 (NRC 1998). The conceptual model for flow and transport in the EBS will be referred to as the ''EBS RT Abstraction'' in this analysis/modeling report (AMR). The scope of this abstraction and report is limited to flow and transport processes. More specifically, this AMR does not discuss elements of the TSPA-SR and TSPA-LA that relate to the EBS but are discussed in other AMRs. These elements include corrosion processes, radionuclide solubility limits, waste form dissolution rates and concentrations of colloidal particles that are generally represented as boundary conditions or input parameters for the EBS RT Abstraction. In effect, this AMR provides the algorithms for transporting radionuclides using the flow geometry and radionuclide concentrations determined by other

  3. Failure of thick, low density air plasma sprayed thermal barrier coatings

    Helminiak, Michael Aaron

    This research was directed at developing fundamental understandings of the variables that influence the performance of air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC). Focus was placed on understanding how and why each variable influenced the performance of the TBC system along with how the individual variables interacted with one another. It includes research on the effect of surface roughness of NiCoCrAlY bond coats deposited by argon-shrouded plasma spraying, the interdiffusion behavior of bond coats coupled to commercial superalloys, and the microstructural and compositional control of APS topcoats to maximize the coating thicknesses that can be applied without spallation. The specimens used for this research were prepared by Praxair Surface Technologies and have been evaluated using cyclic oxidation and thermal shock tests. TBC performance was sensitive to bond coat roughness with the rougher bond coats having improved cyclic performance than the smoother bond coats. The explanation being the rough bond coat surface hindered the propagation of the delamination cracks. The failure mechanisms of the APS coatings were found to depend on a combination of the topcoat thickness, topcoat microstructure and the coefficient of thermal expansion (CTE) mismatch between the superalloy and topcoat. Thinner topcoats tended to fail at the topcoat/TGO interface due to bond coat oxidation whereas thicker topcoats failed within the topcoat due to the strain energy release rate of the thicker coating exceeding the fracture strength of the topcoat. Properties of free-standing high and conventional purity YSZ topcoats of both a lowdensity (LD) and dense-vertically fissure (DVF) microstructures were evaluated. The densification rate and phase evolution were sensitive to the YSZ purity and the starting microstructure. Increasing the impurity content resulted in enhanced sintering and phase decomposition rates, with the exception of the

  4. NO{sub x} emission and thermal efficiency of a 300 MWe utility boiler retrofitted by air staging

    Li, Sen; Wei, Xiaolin [Institute of Mechanics, Chinese Academy of Sciences, No.15 Beisihuanxi Road, Beijing 100080 (China); Xu, Tongmo; Hui, Shien [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, 28 Xian Ning Road, Xi' an 710049 (China)

    2009-09-15

    Full-scale experiments were performed on a 300 MWe utility boiler retrofitted with air staging. In order to improve boiler thermal efficiency and to reduce NO{sub x} emission, the influencing factors including the overall excessive air ratio, the secondary air distribution pattern, the damper openings of CCOFA and SOFA, and pulverized coal fineness were investigated. Through comprehensive combustion adjustment, NO{sub x} emission decreased 182 ppm (NO{sub x} reduction efficiency was 44%), and boiler heat efficiency merely decreased 0.21%. After combustion improvement, high efficiency and low NO{sub x} emission was achieved in the utility coal-fired boiler retrofitted with air staging, and the unburned carbon in ash can maintain at a desired level where the utilization of fly-ash as byproducts was not influenced. (author)

  5. Thermal behavior studies in building using artificial neural network for non air conditioned terrace house in Malaysia

    Strategies to improve energy efficiency in buildings have continuously being improved and becoming more effective as new knowledge on the building behavior and technology continue to develop. Nevertheless, effort to explore for further improvement must continuously undertake to seek more energy efficient and cost effective systems. Artificial Neural Network (ANN) is currently one of the most popular mechanisms to forecast any form of behavior and phenomena. Building thermal behavior can be studied and potential for energy utilization improvement without compromising thermal comfort can be explored using ANN. This paper explores the possibility of monitoring, predicting and forecasting the thermal behavior inside a building space and the optimization of building design. Typical result of experimental data and simulated data is presented. The sample house used adopted various thermal comfort strategies like cross ventilation and space air flow consideration

  6. Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues

    Sørensen, Mette Abildgaard; Bender-Koch, C.; Starckpoole, M. M.;

    2000-01-01

    Stabilization of air pollution control residues by coprecipitation with ferrous iron and subsequent thermal treatment (at 600 and 900 °C) has been examined as a means to reduce heavy metal leaching and to improve product stability. Changes in mineralogy and metal binding were analyzed using various...... analytical and environmental techniques. Ferrihydrite was formed initially but transformed upon thermal treatment to more stable and crystalline iron oxides (maghemite and hematite). For some metals leaching studies showed more substantial binding after thermal treatment, while other metals either....... Thermal treatment of the stabilized residues produced structures with an inherently better iron oxide stability. However, the concentration of metals in the leachate generally increased as a consequence of the decreased solubility of metals in the more stable iron oxide structure....

  7. Numerical study on optical and electric-thermal performance for solar concentrating PV/T air system

    2009-01-01

    Hybrid photovoltaic/thermal(PV/T)system with solar concentrator is an effective way to improve solar energy conversion efficiency.In this work,a single-pass PV/T air system with a three-trough compound parabolic concentrator(CPC)of concentration ratio 2.0 is designed and the solar incident distributions at the solar cell surface are calculated by ray tracing method.Based on energy balance,the heat transfer models of all main components in this system are developed.The effects of some main designing and operational parameters on the electric-thermal performance of the system are analyzed. The results show that the solar radiation intensity can be higher than 1200 W/m 2 at most area of the cell surface.The temperature of the air and cell surface increases along the length of the system.Thus the system efficiency of the CPC is higher than that of the system without the CPC.The thermal efficiency, exergy and electrical efficiency of this CPC system increase with increasing of the air mass flow rate and the length of the system.With increasing packing fraction the electrical efficiency increases,but the thermal efficiency decreases.The exergy efficiency increases slightly with the packing fraction rising.The data obtained in this work are valuable for the design and operation for this kind of solar concentrating PV/T systems.

  8. Brines, thermal springs, and mineralization phenomena along the eastern coast of Sinai as compared to those of the hot deeps of the Red Sea (abstract)

    Issar, A. (Geological Survey of Israel); Rosenthal, E.; Eckstein, Y.; Bogoch, R.

    1969-01-01

    The chemical composition of brines found as formation waters in oil wells and emerging at the thermal springs along the western coast of the Sinai are shown to have equivalent ionic ratios which are similar to those of hot brines found in the three deeps on the bottom of the Red Sea. Along the cliff close to the thermal spring of Hammam el-Far'un, on the shore of the Suez Gulf, iron mineralization, dolomitization, and heavy-metal enrichment have been observed. The mineralization is shown to be similar to that found in cores collected from the Atlantic II, Discovery, and Chain Deeps of the Red Sea. The thermal regime in the area investigated is characterized by high gradient (10-15 m//sup 0/C) foci occurring within areas having lower gradients (up to 50 m//sup 0/C). Similar phenomena have been observed in the region of the Hot Deeps. The metals found in the waters are believed to be connected partly with hydrothermal activity and partly with the leaching of sedimentary formations. It is suggested that the hot brines of the Red Sea may be submarine thermal springs draining out mineralized formation waters trapped in the sediments underlying the Red Sea.

  9. Theoretical and experimental studies of the recovery of volatile organic compounds from waste air streams in the thermal swing adsorption system with closed-loop regeneration of adsorbent

    Highlights: • The TSA process for VOCs recovery from the waste air was studied. • The closed-loop adsorbent regeneration method was used. • A mathematical model was developed to simulate the TSA process. • The toluene–Sorbonorit 4 activated carbon system was studied. • We proved that toluene can be recovered in moderate condensation temperature range. - Abstract: The cyclic thermal swing adsorption (TSA) process for volatile organic compounds (VOCs) recovery from the waste air is studied theoretically and experimentally. Toluene is chosen as the volatile organic compound. Activated carbon Sorbonorit 4 is used as an adsorbent. The TSA cycle is operated in three steps: an adsorption step with cold feed, a desorption step with hot purge gas and a cooling step with cold inert gas. The desorption and cooling are affected by nitrogen circulated through a heater, an adsorber and a condenser. A nonequilibrium, nonisothermal mathematical model is developed to simulate temperature and concentration breakthrough curves for both adsorption and desorption steps. The computer simulation results are compared with the experimental data. A bench scale fixed bed adsorption unit was used for the experimental study. It is shown that the theoretical model predicts the experimental results well. The computer simulation results are used to study the effect of the purge gas and condensation temperature on the process efficiency

  10. ABSTRACTION OF DRIFT SEEPAGE

    probability distributions of seepage. These are all discussed in detail in this report. In addition, the work plan calls for evaluation of effects of episodic flow and thermal-hydrologic-chemical alteration of hydrologic properties. As discussed in Section 5, these effects are not addressed in detail in this report because they can be argued to be insignificant. Effects of thermal-mechanical alteration of hydrologic properties are also not addressed in detail in this report because suitable process-model results are not available at this time. If these effects are found to be important, they should be included in the seepage abstraction in a future revision

  11. Experimental Investigation of Single Pass, Double Duct Photovoltaic Thermal (PV/T Air Collector with CPC and Fins

    M. E.A. Alfegi

    2008-01-01

    Full Text Available The temperature of photovoltaic modules increases when it absorbs solar radiation, causing a decrease in efficiency. This undesirable effect can be partially avoided by applying a heat recovery unit with fluid circulation (air or water with the photovoltaic module. Such unit is called photovoltaic/thermal collector (pv/t or hybrid (pv/t. An experimental investigation of a solar air heater with photovoltaic cell located at the absorber with compound parabolic collector (CPC and fins have been developed and tested. The performance of the photovoltaic, thermal and combined pv/t collector over range of operating conditions and the results was discussed. Results at solar irradiance of 400 W/m2 showed that the combined pv/t efficiency is increasing from 27.50 % to 40.044 % at mass flow rates various from 0.0316 to 0.09 kg-1 s.

  12. The Transmission of Thermal and Fast Neutrons in Air Filled Annular Ducts through Slabs of Iron and Heavy Water

    An investigation has been carried out concerning the transmission of thermal and fast neutrons in air filled annular ducts through laminated Fe-D2O shields. Measurements have been made with annular air gaps of 0.5, 1.0, 1.5 and 2.0 cm, at a duct length of half a meter. The neutron fluxes were determined with a foil activation technique. The thermal flux was theoretically and experimentally divided into three components, a streaming, a leakage and an albedo component. The fast flux was similarly divided into a streaming component and a 'leakage' component. A calculational model to predict the components was then developed and fitted, to the data obtained by experiments. The model reported here for prediction of neutron attenuation in ducted configurations may be applied to straight annular ducts of arbitrary dimensions and material configurations but is especially designed for the problems met with in short ducts

  13. Field study of thermal comfort and preferences in air-conditioned offices in Chongqing,P. R. China

    马小磊; 刘红; 袁杰; 谈美兰

    2009-01-01

    A large-scale field survey to measure indoor environmental parameters such as air temperature,air velocity and relative humidity was conducted in Chongqing,P. R. China,a city in a hot summer and cold winter zone. Subjective questionnaires and the ASHRAE seven-point thermal sensation scale were used to evaluate thermal,humidity and velocity sensations. Probability methods were employed to calculate the preferred temperatures. The results show that the preferred temperatures are 25.1 ℃ in summer and 21.1 ℃ in winter,respectively. Based on a comparison of the difference between neutral and preferred temperatures,it is proposed that human temperature sensitivity influences preferred temperature.

  14. Thermal and hydrodynamic effects of nanosecond discharges in atmospheric pressure air

    We present quantitative schlieren measurements and numerical analyses of the thermal and hydrodynamic effects of a nanosecond repetitively pulsed (NRP) discharge in atmospheric pressure air at 300 and 1000 K. The plasma is created by voltage pulses at an amplitude of 10 kV and a duration of 10 ns, applied at a frequency of 1–10 kHz between two pin electrodes separated by 2 or 4 mm. The electrical energy of each pulse is of the order of 1 mJ. We recorded single-shot schlieren images starting from 50 ns to 3 µs after the discharge. The time-resolved images show the shock-wave propagation and the expansion of the heated gas channel. Gas density profiles simulated in 1D cylindrical coordinates have been used to reconstruct numerical schlieren images for comparison with experimental ones. We propose an original method to determine the initial gas temperature and the fraction of energy transferred into ultrafast gas heating, using a comparison of the contrast profiles obtained from experimental and numerical schlieren images. This method is found to be much more sensitive to these parameters than the direct comparison of measured and predicted shock-wave and heated channel radii. The results show that a significant fraction of the electric energy is converted into gas heating within a few tens of ns. The values range from about 25% at a reduced electric field of 164 Td to about 75% at 270 Td, with a strong dependance on the initial gas temperature. These experiments support the fast heating processes via dissociative quenching of N2(B3 Πg, C3 Πu) by molecular oxygen. (paper)

  15. Abstractions of stochastic hybrid systems

    Bujorianu, L.M.; Bujorianu, M. C.; Lygeros, J.

    2005-01-01

    Many control systems have large, infinite state space that can not be easily abstracted. One method to analyse and verify these systems is reachability analysis. It is frequently used for air traffic control and power plants. Because of lack of complete information about the environment or unpredict

  16. Measurement of the thermal performance of a Borehole Heat Exchanger while injecting air bubbles in the groundwater

    Calzada i Oliveras, Eduard

    2012-01-01

    The most common way to exchange heat with the ground in Ground Source Heat Pump (GSHP) applications is with borehole heat exchangers (energy col-lectors in vertical wells). These boreholes contain the pipe with the secondary fluid of the GSHP and they are often filled with natural groundwater. It has been recently discovered that injecting air bubbles in the groundwater side of the boreholes increases the efficiency of the heat transfer. The aim of this thesis is to analyze the thermal change...

  17. The solar power tower Jülich – a solar thermal power plant for test and demonstration of air receiver

    Hennecke, Klaus; Schwarzbözl, Peter; Hoffschmidt, Bernhard; Göttsche, Joachim; Koll, Gerrit; Beuter, Matthias; Hartz, Thomas

    2007-01-01

    The paper explains the fundamentals of the open volumetric receiver technology and shows the history of its development. It gives technical information about the system definition and the engineering of the Solar Power Tower Jülich. The open volumetric receiver technology allows the use of air as heat transfer medium at high temperatures in solar thermal power tower plants. It combines porous ceramic or metallic absorber structures with a strictly modular receiver design. Highly concentrat...

  18. Modelling LiBr-H2O solution concentration/crystallization of low thermal-powered absorption air conditioning system

    A computer model is developed to predict the concentration of lithium bromide - water (LiBr-H2O) solution for used in low thermal energy-driven absorption air conditioning plants design. The computer program is capable to alert the users from undesirable solidification or crystallization zones. Good agreements between simulated concentration and experimental data from standard chart/table have been obtained. (Author)

  19. Six years of ground–air temperature tracking at Malence (Slovenia): thermal diffusivity from subsurface temperature data

    Dědeček, Petr; Rajver, D.; Čermák, Vladimír; Šafanda, Jan; Krešl, Milan

    2013-01-01

    Roč. 10, č. 2 (2013), 025012/1-025012/9. ISSN 1742-2132 R&D Projects: GA ČR(CZ) GAP210/11/0183; GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : ground-air temperature coupling * thermal diffusivity * conductive-convective heat transfer Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.895, year: 2013

  20. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Mohamed F. Zedan; Sami Al-Sanea; Abdulaziz Al-Mujahid; Zeyad Al-Suhaibani

    2016-01-01

    Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which br...

  1. Thermodynamic analysis of a hybrid thermal-compressed air energy storage system for the integration of wind power

    In China, a large amount of wind power is abandoned due to the difficulty of integrating fluctuating wind power into electricity grid systems. Advanced adiabatic compressed air energy storage (AA-CAES) is regarded as a promising emission-free technology to facilitate the wind power integration, but its high capital cost has hindered its wide commercialization. In the present work, a novel hybrid system was proposed on the basis of AA-CAES. It can reduce abandoned wind power and improve the financial return per capital cost of the system by increasing power output. In the new system, which is called hybrid thermal-compressed air energy storage (HTCAES), thermal energy storage (TES) units absorb the heat released from air compression and also the thermal energy converted from reluctant wind power using electrical heaters. Theoretical thermodynamic analyses show that the HTCAES system can absorb much more wind power than an AA-CAES system with the same scale of compressors, turbines, and TES units do. And recovery efficiency of this additional wind power is about 41–47%, depending on the final storage temperature of the TES. The power output ratio of the HTCAES system to the AA-CAES system increases with the maximum TES storage temperature and decreases with the operating pressure. - Highlights: •A novel concept of adiabatic compressed air energy storage is proposed. •Heat TES using electricity heaters after TES absorbs heat from air. •Power storage capacity of the new system can be greatly increased. •Recovery efficiency of the wind power used for electric heating is about 41–47%. •Power output increase is about 19–125% depending on the TES storage temperature

  2. Air

    ... house) Industrial emissions (like smoke and chemicals from factories) Household cleaners (spray cleaners, air fresheners) Car emissions (like carbon monoxide) *All of these things make up “particle pollution.” They mostly come from cars, trucks, buses, and ...

  3. Impact of kiln thermal energy demand and false air on cement kiln flue gas CO2 capture

    Udara S. P. R. Arachchige, Dinesh Kawan, Lars-André Tokheim, Morten C. Melaaen

    2014-01-01

    Full Text Available The present study is focused on the effect of the specific thermal energy demand and the false air factor on carbon capture applied to cement kiln exhaust gases. The carbon capture process model was developed and implemented in Aspen Plus. The model was developed for flue gases from a typical cement clinker manufacturing plant. The specific thermal energy demand as well as the false air factor of the kiln system were varied in order to determine the effect on CO2 capture plant performance, such as the solvent regeneration energy demand. In general, an increase in the mentioned kiln system factors increases the regeneration energy demand. The reboiler energy demand is calculated as 3270, 3428 and 3589 kJ/kg clinker for a specific thermal energy of 3000, 3400 and 3800 kJ/kg clinker, respectively. Setting the false air factor to 25, 50 or 70% gives a reboiler energy demand of 3428, 3476, 3568 kJ/kg clinker, respectively.

  4. Determination of Efficiency of Hybrid Photovoltaic Thermal Air Collectors Using Artificial Neural Network Approach for Different PV Technology

    G. N. Tiwari

    2012-01-01

    Full Text Available In this paper an attempt has been made to determine efficiency of semi transparent hybrid photovoltaic thermal double pass air collector for different PV technology and compare it with single pass air collector using artificial neural network (ANN technique for New Delhi weather station of India. The MATLAB 7.1 neural networks toolbox has been used for defining and training of ANN for determination of thermal, electrical, overall thermal and overall exergy efficiency of the system. The ANN model uses ambient air temperature, number of sunshine hours, number of clear days, temperature coefficient, cell efficiency, global and diffuse radiation as input parameters. The transfer function, neural network configuration and learning parameters have been selected based on highest convergence during training and testing of network. About 2000 sets of data from four weather stations (Bangalore, Mumbai, Srinagar and Jodhpur have been given as input for training and data of the fifth weather station (New Delhi has been used for testing purpose. It has been observed that the best transfer function for a given configuration is logsig. The feed forward back-propagation algorithm has been used in this analysis. Further the results of ANN model have been compared with analytical values on the basis of root mean square error.

  5. Design and parametric optimization of thermal management of lithium-ion battery module with reciprocating air-flow

    刘燕平; 欧阳陈志; 江清柏; 梁波

    2015-01-01

    Single cell temperature difference of lithium-ion battery (LIB) module will significantly affect the safety and cycle life of the battery. The reciprocating air-flow module created by a periodic reversal of the air flow was investigated in an effort to mitigate the inherent temperature gradient problem of the conventional battery system with a unidirectional coolant flow with computational fluid dynamics (CFD). Orthogonal experiment and optimization design method based on computational fluid dynamics virtual experiments were developed. A set of optimized design factors for the cooling of reciprocating air flow of LIB thermal management was determined. The simulation experiments show that the reciprocating flow can achieve good heat dissipation, reduce the temperature difference, improve the temperature homogeneity and effectively lower the maximal temperature of the modular battery. The reciprocating flow improves the safety, long-term performance and life span of LIB.

  6. Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

    Li, Ruixin; Sekhar, S.C.; Melikov, Arsen Krikor

    2010-01-01

    The potential for improving occupants' thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied by...... the results obtained reveal improved acceptability of perceived air quality and improved thermal sensation with PV-UFAD in comparison with the reference case of UFAD alone or mixing ventilation with ceiling supply diffuser. The local thermal sensation at the feet was also improved when warmer UFAD...

  7. Energy and exergy analysis of a two pass photovoltaic –thermal (PV/T) air heater

    Srinivas, M.; Jayaraj, S. [Department of Mechanical Engineering, National Institute of Technology, Calicut-673601 (India)

    2013-07-01

    A double pass hybrid solar air (PV/T) heater with slats is designed and fabricated to study elaborately its thermal and electrical performance corresponding to the warm and humid environment. Air as a heat removing fluid is made to flow through upper and lower channels of the collector. The collector is designed in such way that the absorber plate is partially covered by solar cells. Thin metallic strips (called slats) are attached longitudinally at the bottom side of the absorber plate to improve the overall system performance (by increasing the cooling rate of the absorber plate). Thermal and electrical performances of the whole system at different cooling rates are presented. The exergy analysis of double pass hybrid solar air (PV/T) heater with slats has also been carried out. The instantaneous overall energy and overall exergy efficiency of the double pass hybrid (PV/T) solar air heater varies between 29 – 37 percent and 14-17 percent respectively. These obtained values are comparable with that of published results.

  8. [Determination of volatile organic compounds in ambient air by thermal desorption-gas chromatography-triple quadrupole tandem mass spectrometry].

    Feng, Lili; Hu, Xiaofang; Yu, Xiaojuan; Zhang, Wenying

    2016-02-01

    A method was established for the simultaneous determination of 23 volatile organic compounds (VOCs) in ambient air with combination of thermal desorption (TD) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). The air samples were collected by active sampling method using Tenax-TA sorbent tubes, and desorbed by thermal desorption. The analytes were determined by GC-MS/MS in selected reaction monitoring (SRM) mode, and internal standard method was applied to quantify the VOCs. The results of all the 23 VOCs showed good linearities in low level (0. 01-1 ng) and high level (1-100 ng) with all the correlation coefficients (r2) more than 0. 99. The method quantification limits were between 0. 000 08-1 µg/m3. The method was validated by means of recovery experiments (n = 6) at three spiked levels of 2, 10 and 50 ng. The recoveries between 77% and 124% were generally obtained. The relative standard deviations (RSDs) in all cases were lower than 20%, except for chlorobenzene at the low spiked level. The developed method was applied to determine VOCs in ambient air collected at three sites in Shanghai. Several compounds, like benzene, toluene, ethylbenzene, m-xylenes, p-xylenes, styrene, 1, 2, 4-trimethylbenzene and hexachlorobutadiene were detected and confirmed in all the samples analyzed. The method is highly accurate, reliable and sensitive for monitoring the VOCs in ambient air. PMID:27382728

  9. Thermal characteristics of air-water spray impingement cooling of hot metallic surface under controlled parametric conditions

    Nayak, Santosh Kumar; Mishra, Purna Chandra

    2016-06-01

    Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper. The controlling input parameters investigated were the combined air and water pressures, plate thickness, water flow rate, nozzle height from the target surface and initial temperature of the hot surface. The effects of these input parameters on the important thermal characteristics such as heat transfer rate, heat transfer coefficient and wetting front movement were measured and examined. Hot flat plate samples of mild steel with dimension 120 mm in length, 120 mm breadth and thickness of 4 mm, 6 mm, and 8 mm respectively were tested. The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface. Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e, 4 mm thick plates. Increase in the nozzle height reduced the heat transfer efficiency of spray cooling. At an inlet water pressure of 4 bar and air pressure of 3 bar, maximum cooling rates 670°C/s and average cooling rate of 305.23°C/s were achieved for a temperature of 850°C of the steel plate.

  10. Thermal Characteristics of Air-Water Spray Impingement Cooling of Hot Metallic Surface under Controlled Parametric Conditions

    Santosh Kumar Nayak; Purna Chandra Mishra

    2016-01-01

    Experimental results on the thermal characteristics of air-water spray impingement cooling of hot metallic surface are presented and discussed in this paper.The controlling input parameters investigated were the combined air and water pressures,plate thickness,water flow rate,nozzle height from the target surface and initial temperature of the hot surface.The effects of these input parameters on the important thermal characteristics such as heat transfer rate,heat transfer coefficient and wetting front movement were measured and examined.Hot flat plate samples of mild steel with dimension 120 mm in length,120 mm breadth and thickness of 4 mm,6 mm,and 8 mm respectively were tested.The air assisted water spray was found to be an effective cooling media and method to achieve very high heat transfer rate from the surface.Higher heat transfer rate and heat transfer coefficients were obtained for the lesser i.e,4 mm thick plates.Increase in the nozzle height reduced the heat transfer efficiency of spray cooling.At an inlet water pressure of 4 bar and air pressure of 3 bar,maximum cooling rates 670℃/s and average cooling rate of 305.23℃/s were achieved for a temperature of 850℃ of the steel plate.

  11. Gas exchange in wetlands with emergent vegetation: The effects of wind and thermal convection at the air-water interface

    Poindexter, Cristina M.; Variano, Evan A.

    2013-07-01

    Methane, carbon dioxide, and oxygen are exchanged between wetlands and the atmosphere through multiple pathways. One of these pathways, the hydrodynamic transport of dissolved gas through the surface water, is often underestimated in importance. We constructed a model wetland in the laboratory with artificial emergent plants to investigate the mechanisms and magnitude of this transport. We measured gas transfer velocities, which characterize the near-surface stirring driving air-water gas transfer, while varying two stirring processes important to gas exchange in other aquatic environments: wind and thermal convection. To isolate the effects of thermal convection, we identified a semiempirical model for the gas transfer velocity as a function of surface heat loss. The laboratory results indicate that thermal convection will be the dominant mechanism of air-water gas exchange in marshes with emergent vegetation. Thermal convection yielded peak gas transfer velocities of 1 cm h-1. Because of the sheltering of the water surface by emergent vegetation, gas transfer velocities for wind-driven stirring alone are likely to exceed this value only in extreme cases.

  12. Optimization of thermal performance of a smooth flat-plate solar air heater using teaching–learning-based optimization algorithm

    R. Venkata Rao

    2015-12-01

    Full Text Available This paper presents the performance of teaching–learning-based optimization (TLBO algorithm to obtain the optimum set of design and operating parameters for a smooth flat plate solar air heater (SFPSAH. The TLBO algorithm is a recently proposed population-based algorithm, which simulates the teaching–learning process of the classroom. Maximization of thermal efficiency is considered as an objective function for the thermal performance of SFPSAH. The number of glass plates, irradiance, and the Reynolds number are considered as the design parameters and wind velocity, tilt angle, ambient temperature, and emissivity of the plate are considered as the operating parameters to obtain the thermal performance of the SFPSAH using the TLBO algorithm. The computational results have shown that the TLBO algorithm is better or competitive to other optimization algorithms recently reported in the literature for the considered problem.

  13. Air

    In recent years several regulations and standards for air quality and limits for air pollution were issued or are in preparation by the European Union, which have severe influence on the environmental monitoring and legislation in Austria. This chapter of the environmental control report of Austria gives an overview about the legal situation of air pollution control in the European Union and in specific the legal situation in Austria. It gives a comprehensive inventory of air pollution measurements for the whole area of Austria of total suspended particulates, ozone, volatile organic compounds, nitrogen oxides, sulfur dioxide, carbon monoxide, heavy metals, benzene, dioxin, polycyclic aromatic hydrocarbons and eutrophication. For each of these pollutants the measured emission values throughout Austria are given in tables and geographical charts, the environmental impact is discussed, statistical data and time series of the emission sources are given and legal regulations and measures for an effective environmental pollution control are discussed. In particular the impact of fossil-fuel power plants on the air pollution is analyzed. (a.n.)

  14. Air Quality Over Baghdad City Using Earth Observation And Landsat Thermal Data

    Salah A. H. Saleh

    2011-01-01

    Air pollution problem is a major concern in many large cities and becomes increasingly critical in this present-day in developed or developing countries around the world. Mapping of urban air pollution dispersion is very complex as it depends upon various factors including weather conditions, urban structural features and their topologies. Air pollution dispersion distribution can be mapped by using mathematical models and interpolation methods based on ground local measurements of meteorolog...

  15. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Mohamed F. Zedan

    2016-06-01

    Full Text Available Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which broadly include ventilation, transmission, solar and internal loads, are considered with schedules based on local lifestyles. The thermal bridging effect of mortar joints is simulated by reducing wall thermal resistance by a percentage that depends on the bridges to wall area ratio (TB area ratio or Amj/Atot and the nominal thermal insulation thickness (Lins. These percentage reductions are obtained from a correlation developed by using a rigorous 2D dynamic model of heat transmission through walls with mortar joints. The reduction in thermal resistance is achieved through minor reductions in insulation thickness, thereby keeping the thermal mass of the wall essentially unchanged. Results indicate that yearly and monthly cooling loads increase almost linearly with the thermal bridge to wall area ratio. The increase in the villa’s yearly loads varies from about 3% for Amj/Atot = 0.02 to about 11% for Amj/Atot = 0.08. The monthly increase is not uniform over the year and reaches a maximum in August, where it ranges from 5% for Amj/Atot = 0.02 to 15% for Amj/Atot = 0.08. In winter, results show that yearly heating loads are generally very small compared to cooling loads and that heating is only needed in December, January and February, starting from late night to late morning. Monthly heating loads increase with the thermal bridge area ratio; however, the variation is not as linear as observed in cooling loads. The present results highlight the importance of

  16. Piaget on Abstraction.

    Moessinger, Pierre; Poulin-Dubois, Diane

    1981-01-01

    Reviews and discusses Piaget's recent work on abstract reasoning. Piaget's distinction between empirical and reflective abstraction is presented; his hypotheses are considered to be metaphorical. (Author/DB)

  17. Programme and abstracts

    Abstracts of 25 papers presented at the congress are given. The abstracts cover various topics including radiotherapy, radiopharmaceuticals, radioimmunoassay, health physics, radiation protection and nuclear medicine

  18. Optimization of air conditioning systems utilizing low temperature thermal storage; Optimizacion de sistemas de acondicionamiento de aire utilizando sistemas de almacenamiento termico de baja temperatura

    Contreras Ramirez, J.; Dorantes Rodriguez, R. [Departamento de Energia, Universidad Autonoma Metropolitana - Unidad Azcapotzalco, Mexico, D. F. (Mexico)

    1997-12-31

    In the last few years the different projects on the saving and efficient use of energy in the tertiary sector have been demonstrating the existing great potential in the air conditioning systems and equipment, whose intensive use is due to the predominance of hot and dry and hot and humid climate prevailing in a large part of the Mexican territory. Without any doubts one of the most serious problems facing the complex management and optimization of these systems is related to the variability of the thermal load and the regulation possibilities of the thermal machines, so as to attain, along the day an appropriate use and optimization of the total installed load, with the best possible economic benefits. Among the strategies that allow the optimization of the installed capacity and the variability of the thermal load is the low temperature thermal storage, for instance, the storage of ice, which is produced and stored to be used when the cooling machines are in standby in order to use this stored energy during the peak hours and during the normal operation of the equipment, but diminishing in a significant amount the electrical demand of the system to satisfy the thermal load with a combination thermal storage-cooling machine. This paper presents some case histories and the type of thermal storage commonly used; a methodology is discussed that allows to determine technically as well as economically the size of a thermal storage room. Some problems in the control and operation of these thermal systems are also presented. [Espanol] En los ultimos anos los diversos proyectos sobre ahorro y uso eficiente de la energia en el sector terciario han venido mostrando el gran potencial existente en los sistemas y equipos de aire acondicionado, cuyo uso intensivo se debe al predominio de los climas calidos seco y calido humedo en buena parte del territorio nacional. Sin lugar a dudas uno de los problemas mas serios que enfrenta la compleja gestion y optimizacion de estos

  19. Increasing reliability of gas-air systems of piston and combined internal combustion engines by improving thermal and mechanic flow characteristics

    Brodov, Yu. M.; Grigor'ev, N. I.; Zhilkin, B. P.; Plotnikov, L. V.; Shestakov, D. S.

    2015-12-01

    Results of experimental study of thermal and mechanical characteristics of gas exchange flow in piston and combined engines are presented. Ways for improving intake and exhaust processes to increase reliability of gas-air engine systems are proposed.

  20. High-Temperature Thermal Storage System for Solar Tower Power Plants with Open-Volumetric Air Receiver Simulation and Energy Balancing of a Discretized Model

    Kronhardt, Valentina; Alexopoulos, Spiros; Reißel, Martin; Sattler, Johannes; Hoffschmidt, Bernhard; Hänel, Matthias; Doerbeck, Till

    2013-01-01

    This paper describes the modeling of a high-temperature storage system for an existing solar tower power plant with open volumetric receiver technology, which uses air as heat transfer medium (HTF). The storage system model has been developed in the simulation environment Matlab/Simulink®. The storage type under investigation is a packed bed thermal energy storage system which has the characteristics of a regenerator. Thermal energy can be stored and discharged as required via the HTF air. ...

  1. Thermal management improvement of an air-cooled high-power lithium-ion battery by embedding metal foam

    Mohammadian, Shahabeddin K.; Rassoulinejad-Mousavi, Seyed Moein; Zhang, Yuwen

    2015-11-01

    Effect of embedding aluminum porous metal foam inside the flow channels of an air-cooled Li-ion battery module was studied to improve its thermal management. Four different cases of metal foam insert were examined using three-dimensional transient numerical simulations. The effects of permeability and porosity of the porous medium as well as state of charge were investigated on the standard deviation of the temperature field and maximum temperature inside the battery in all four cases. Compared to the case of no porous insert, embedding aluminum metal foam in the air flow channel significantly improved the thermal management of Li-ion battery cell. The results also indicated that, decreasing the porosity of the porous structure decreases both standard deviation of the temperature field and maximum temperature inside the battery. Moreover, increasing the permeability of the metal foam drops the maximum temperature inside the battery while decreasing this property leads to improving the temperature uniformity. Our results suggested that, among the all studied cases, desirable temperature uniformity and maximum temperature were achieved when two-third and the entire air flow channel is filled with aluminum metal foam, respectively.

  2. Design and optimization of personalized ventilation for overall improvement of thermal comfort, air quality, and energy efficiency

    Metzger, Ian Dominic

    This paper presents a simple and repeatable CFD-based method that can accurately predict the optimal operating conditions of personalized ventilation systems. In contrast to previous studies, the optimal performance of the PV system includes the influences of various operation characteristics (supply air velocity, PV flow rate, PV temperature, PV distance from face, turbulence intensity, relative humidity, central system flow rate, central system temperature, central system type, and PV on/off operation) on three critical performance factors: thermal comfort, indoor air quality, and energy savings. This method is able to predict more achievable and comprehensive operating performance of PV systems. It is found for the computer perimeter grill air terminal device that supply temperatures, central flow rate, and PV flow rate are the most influential factors on performance in terms of thermal comfort, IAQ, and energy. Using the Taguchi design of experiment and optimal performance prediction method, the computer perimeter grill personalized ventilation system is optimized in conjunction with under-floor and overhead central systems, separately.

  3. Novel Air Flow Meter for an Automobile Engine Using a Si Sensor with Porous Si Thermal Isolation

    Androula G. Nassiopoulou

    2012-11-01

    Full Text Available An air flow meter for measuring the intake air of an automobile engine is presented. It is based on a miniaturized silicon thermal mass flow sensor using a thick porous Si (Po-Si layer for local thermal isolation from the Si substrate, on which the sensor active elements are integrated. The sensor is mounted on one side of a printed circuit board (PCB, on the other side of which the readout and control electronics of the meter are mounted. The PCB is fixed on a housing containing a semi-cylindrical flow tube, in the middle of which the sensor is situated. An important advantage of the present air flow meter is that it detects with equal sensitivity both forward and reverse flows. Two prototypes were fabricated, a laboratory prototype for flow calibration using mass flow controllers and a final demonstrator with the housing mounted in an automobile engine inlet tube. The final demonstrator was tested in real life conditions in the engine inlet tube of a truck. It shows an almost linear response in a large flow range between –6,500 kg/h and +6,500 kg/h, which is an order of magnitude larger than the ones usually encountered in an automobile engine.

  4. Novel air flow meter for an automobile engine using a Si sensor with porous Si thermal isolation.

    Hourdakis, Emmanouel; Sarafis, Panagiotis; Nassiopoulou, Androula G

    2012-01-01

    An air flow meter for measuring the intake air of an automobile engine is presented. It is based on a miniaturized silicon thermal mass flow sensor using a thick porous Si (Po-Si) layer for local thermal isolation from the Si substrate, on which the sensor active elements are integrated. The sensor is mounted on one side of a printed circuit board (PCB), on the other side of which the readout and control electronics of the meter are mounted. The PCB is fixed on a housing containing a semi-cylindrical flow tube, in the middle of which the sensor is situated. An important advantage of the present air flow meter is that it detects with equal sensitivity both forward and reverse flows. Two prototypes were fabricated, a laboratory prototype for flow calibration using mass flow controllers and a final demonstrator with the housing mounted in an automobile engine inlet tube. The final demonstrator was tested in real life conditions in the engine inlet tube of a truck. It shows an almost linear response in a large flow range between –6,500 kg/h and +6,500 kg/h, which is an order of magnitude larger than the ones usually encountered in an automobile engine. PMID:23202189

  5. Numerical study on optical and electric-thermal performance for solar concentrating PV/T air system

    SUN Jian; SHI MingHeng

    2009-01-01

    Hybrid photovoltaic/thermsl(PV/T)system with solar concentrator is an effective way to improve solar energy conversion efficiency.In this work,a single-pass PV/T sir system with a three-trough compound parabolic concentrator(CPC)of concentration ratio 2.0 is designed and the solar incident distributions at the solar cell surface are calculated by ray tracing method.Based on energy balance,the heat transfer models of all main components in this system are developed.The effects of some main designing and operational parameters on the electric-thermal performance of the system are analyzed.The results show that the solar radiation intensity can be higher than 1200 W/m~2 at most area of the cell surface.The temperature of the air and cell surface increases along the length of the system.Thus the system efficiency of the CPC is higher than that of the system without the CPC.The thermal efficiency,exergy and electrical efficiency of this CPC system increase with increasing of the air mass flow rate and the length of the system.With increasing packing fraction the electrical efficiency increases,but the thermal efficiency decreases.The exergy efficiency increases slightly with the packing fraction rising.The data obtained in this work are valuable for the design and operation for this kind of solar concentrating PV/T systems.

  6. The effects of electron thermal radiation on laser ablative shock waves from aluminum plasma into ambient air

    Sai Shiva, S.; Leela, Ch.; Prem Kiran, P.; Sijoy, C. D.; Chaturvedi, S.

    2016-05-01

    The effect of electron thermal radiation on 7 ns laser ablative shock waves from aluminum (Al) plasma into an ambient atmospheric air has been numerically investigated using a one-dimensional, three-temperature (electron, ion, and radiation) radiation hydrodynamic code MULTI. The governing equations in Lagrangian form are solved using an implicit scheme for planar, cylindrical, and spherical geometries. The shockwave velocities (Vsw) obtained numerically are compared with our experimental values obtained over the intensity range of 2.0 × 1010 to 1.4 × 1011 W/cm2. It is observed that the numerically obtained Vsw is significantly influenced by the thermal radiation effects which are found to be dominant in the initial stage up to 2 μs depending on the input laser energy. Also, the results are found to be sensitive to the co-ordinate geometry used in the simulation (planar, cylindrical, and spherical). Moreover, it is revealed that shock wave undergoes geometrical transitions from planar to cylindrical nature and from cylindrical to spherical nature with time during its propagation into an ambient atmospheric air. It is also observed that the spatio-temporal evolution of plasma electron and ion parameters such as temperature, specific energy, pressure, electron number density, and mass density were found to be modified significantly due to the effects of electron thermal radiation.

  7. Impacts of dynamic interactions on the predicted thermal performance of earth–air heat exchangers for preheating, cooling and ventilation of buildings

    Gan, Guohui

    2015-01-01

    Earth–air tunnel ventilation is an energy efficient ventilation technique that makes use of relatively stable soil temperature in shallow ground for preheating and cooling of supply air to a building. During operation, an earth–air heat exchanger interacts with the soil and atmosphere and the performance varies with the soil and atmospheric conditions. A computer program has been developed for modelling of coupled heat and moisture transfer in soil and for simulation of the dynamic thermal pe...

  8. Comparison of mass and energy balances for air blown and thermally ballasted fluidized bed gasifiers

    The objective of this study was to compare the mass and energy balances for a conventional air blown fluidized bed gasifier and a ballasted fluidized bed gasifier developed at Iowa State University. The ballasted gasifier is an indirectly heated gasifier that uses a single reactor for both combustion and pyrolysis. Heat accumulated in high-temperature phase change material during the combustion phase is released during the pyrolysis phase to generate producer gas. Gas composition, tar and char contents, cold gas efficiency, carbon conversion, and hydrogen yield per unit biomass input were determined as part of these evaluation. During the pyrolysis phase of ballasted gasification, higher volumetric concentrations of hydrogen and methane were obtained than during air blown gasification. Hydrogen yield for ballasted gasification was 14 g kg−1 of biomass, which was about 20% higher than that obtained during air blown gasification. The higher heating value of the producer gas also reached higher levels during the ballasted pyrolysis phase than that of air blown gasification. Heating value for air blown gasification was 5.2 MJ m−3 whereas the heating value for the ballasted pyrolysis phase averaged 5.5 MJ m−3, reaching a maximum of 8.0 MJ m−3. The ballasted gasifier was expected to yield producer gas with average heating value as high as 15 MJ m−3 but excessive use of nitrogen to purge and cool the fuel feeder system greatly diluted the producer gas. Relatively simple redesign of the feeder system would greatly reduce the use of purge gas and may increase the heating values to about 17.5 MJ m−3. Higher char production per kilogram of biomass was associated with the ballasted system, producing 140 g kg−1 of biomass compared to only 53 g kg−1 of biomass during air blown gasification. On the other hand, tar concentrations in the producer gas were 6.0 g m−3 for ballasted gasification compared to 11.7 g m−3 for air blown gasification. On balance, carbon

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

    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)

  10. Calculation and analysis of the mobility and diffusion coefficient of thermal electrons in methane/air premixed flames

    Bisetti, Fabrizio

    2012-12-01

    Simulations of ion and electron transport in flames routinely adopt plasma fluid models, which require transport coefficients to compute the mass flux of charged species. In this work, the mobility and diffusion coefficient of thermal electrons in atmospheric premixed methane/air flames are calculated and analyzed. The electron mobility is highest in the unburnt region, decreasing more than threefold across the flame due to mixture composition effects related to the presence of water vapor. Mobility is found to be largely independent of equivalence ratio and approximately equal to 0.4m 2V -1s -1 in the reaction zone and burnt region. The methodology and results presented enable accurate and computationally inexpensive calculations of transport properties of thermal electrons for use in numerical simulations of charged species transport in flames. © 2012 The Combustion Institute.