WorldWideScience

Sample records for hvac system consists

  1. HVAC systems design handbook

    CERN Document Server

    Haines, Roger W

    2010-01-01

    Thoroughly updated with the latest codes, technologies, and practices, this all-in-one resource provides details, calculations, and specifications for designing efficient and effective residential, commercial, and industrial HVAC systems. HVAC Systems Design Handbook, Fifth Edition, features new information on energy conservation and computer usage for design and control, as well as the most recent International Code Council (ICC) Mechanical Code requirements. Detailed illustrations, tables, and essential HVAC equations are also included. This comprehensive guide contains everything you need to design, operate, and maintain peak-performing HVAC systems.

  2. Next Generation HVAC System

    Science.gov (United States)

    Takagi, Yasuo; Murakami, Yoshiki; Hanada, Yuuichi; Nishimura, Nobutaka; Yamazaki, Kenichi; Itoh, Yasuyuki

    A new HVAC (Heating, Ventilating, and Air-Conditioning) system for buildings is proposed. The key technology for the system is a twin coil air handling unit (AHU) and its advanced control method. One coil is equipped to cool and dehumidify the fresh air intake, and the other coil is for cooling circulated air. The deeply chilled water is necessary only for removing the moisture from the fresh air. The latter coil requires moderately cool water according to the HVAC load. Then 2 kinds of chilled water in terms of temperature should be prepared. The structure helps saving the energy consumption for air-conditioning because the higher chilled water temperature implies the better chiller efficiency (COP: Coefficient of Performance). In addition, an advanced control method that is called an ‘Air-Water cooperation system’ is introduced. The control system mainly focuses on energy savings through changing the temperature of the chilled water and supply air according to the HVAC load and weather conditions. In this paper, we introduce a Next Generation HVAC system with its control system and present evaluation results of the system for the model-building simulator.

  3. HVAC control system for building automation

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. S.; Song, I. T.; Cho, S. W.; Cho, J. H. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    The purpose of the project is to design and construction of the HVAC control system for building automation. The HVAC control system can accomplish the function which are the optimum operation condition and operation time, and the operation pattern analysis. Also, this control system can effectively manage energy saving, building environment control, facilities safety monitoring etc. The HVAC control system consisted of the central control and monitoring system (CCMS) and the direct digital controller (DDC). 1) CCMS: -Main Compute -Graphic Board -Printer -Console Desk -Intercom. 2) DDC : -IMC-M (System Control Unit Main Module) -IMC-1,2,3,4(System Control Unit Module). Following this report will be used important data for the design, construction, operation and maintenance of the HVAC control system. 12 refs., 6 figs., 9 tabs. (Author)

  4. Towards Autonomous Control of HVAC Systems

    DEFF Research Database (Denmark)

    Brath, P.

    This thesis considered development of an autonomous control system for heating ventilation and air conditioning applications. By including auto-tuning, adaptation, diagnosis and supervision functions in the control system used in the HVAC industry will move the control of HVAC systems towards...... autonomous control. Together with better tuned controllers and more dedicated control it would be possible to decrease the energy consumption, save money and increase the indoor air climate. A flexible HVAC test system was designed and implemented. Standard components and sensors were used in the design...

  5. Optimal Model-Based Control in HVAC Systems

    DEFF Research Database (Denmark)

    Komareji, Mohammad; Stoustrup, Jakob; Rasmussen, Henrik;

    2008-01-01

    This paper presents optimal model-based control of a heating, ventilating, and air-conditioning (HVAC) system. This HVAC system is made of two heat exchangers: an air-to-air heat exchanger (a rotary wheel heat recovery) and a water-to- air heat exchanger. First dynamic model of the HVAC system...

  6. Intelligent control of HVAC systems. Part I: Modeling and synthesis

    Directory of Open Access Journals (Sweden)

    Adrian TOADER

    2013-03-01

    Full Text Available This is the first part of a work on intelligent type control of Heating, Ventilating and Air-Conditioning (HVAC systems. The study is performed from the perspective of giving a unitary control method to ensure high energy efficiency and air quality improving. To illustrate the proposed HVAC control technique, in this first part it is considered as benchmark problem a single thermal space HVAC system. The construction of the mathematical model is performed only with a view to obtain a framework of HVAC intelligent control validation by numerical simulations. The latter will be reported in a second part of the study.

  7. Why, when and how do HVAC-systems pollute? Characterisation of HVAC-systems related pollution

    NARCIS (Netherlands)

    Bluyssen, P.M.; Björkroth, M.; Müller, B.; Oliveira Fernandes, E. de; Roulet, C.A.

    2000-01-01

    In the beginning of 1998 a three-year European project, AIRLESS, was started to develop strategies, principles and protocols to improve and control the performance of HVAC-systems and its components for incorporation in codes and guidelines. Twelve institutes, universities and companies from seven

  8. Maintenance of HVAC-systems and components: How to prevent pollution from HVAC-systems?

    NARCIS (Netherlands)

    Müller, B.; Björkroth, M.; Plitt, U.; Bluyssen, P.M.

    2000-01-01

    In the beginning of 1998 a three-year European project, AIRLESS, was started to develop strategies, principles and protocols to improve and control the performance of HVAC-systems and its components for incorporation in codes and guidelines. Twelve institutes, universities and companies, from seven

  9. [Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

    Science.gov (United States)

    Bellucci Sessa, R; Riccio, G

    2004-01-01

    After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

  10. Design Concepts for Optimum Energy Use in HVAC Systems.

    Science.gov (United States)

    Electric Energy Association, New York, NY.

    Much of the innovative work in the design and application of heating, ventilating, and air conditioning (HVAC) systems is concentrated on improving the cost effectiveness of such systems through optimizing energy use. One approach to the problem is to reduce a building's HVAC energy demands by designing it for lower heat gains and losses in the…

  11. Optimal Set-Point Synthesis in HVAC Systems

    DEFF Research Database (Denmark)

    Komareji, Mohammad; Stoustrup, Jakob; Rasmussen, Henrik

    2007-01-01

    components, encompassing fans, primary/secondary pump, tertiary pump, and air-to-air heat exchanger wheel; and a fraction of thermal power used by the HVAC system. The goals that have to be achieved by the HVAC system appear as constraints in the optimization problem. To solve the optimization problem......This paper presents optimal set-point synthesis for a heating, ventilating, and air-conditioning (HVAC) system. This HVAC system is made of two heat exchangers: an air-to-air heat exchanger and a water-to-air heat exchanger. The objective function is composed of the electrical power for different......, a steady state model of the HVAC system is derived while different supplying hydronic circuits are studied for the water-to-air heat exchanger. Finally, the optimal set-points and the optimal supplying hydronic circuit are resulted....

  12. Real-time supervision of building HVAC system performance

    Energy Technology Data Exchange (ETDEWEB)

    Djuric, Natasa

    2008-07-01

    This thesis presents techniques for improving building HVAC system performance in existing buildings generated using simulation-based tools and real data. Therefore, one of the aims has been to research the needs and possibilities to assess and improve building HVAC system performance. In addition, this thesis aims at an advanced utilization of building energy management system (BEMS) and the provision of useful information to building operators using simulation tools. Buildings are becoming more complex systems with many elements, while BEMS provide many data about the building systems. There are, however, many faults and issues in building performance, but there are legislative and cost-benefit forces induced by energy savings. Therefore, both BEMS and the computer-based tools have to be utilized more efficiently to improve building performance. The thesis consists of four main parts that can be read separately. The first part explains the term commissioning and the commissioning tool work principal based on literature reviews. The second part presents practical experiences and issues introduced through the work on this study. The third part deals with the computer-based tools application in design and operation. This part is divided into two chapters. The first deals with improvement in the design, and the second deals with the improvement in the control strategies. The last part of the thesis gives several rules for fault diagnosis developed using simulation tools. In addition, this part aims at the practical explanation of the faults in the building HVAC systems. The practical background for the thesis was obtained though two surveys. The first survey was carried out with the aim to find the commissioning targets in Norwegian building facilities. In that way, an overview of the most typical buildings, HVAC equipment, and their related problems was obtained. An on-site survey was carried out on an example building, which was beneficial for introducing the

  13. Ontology for Life-Cycle Modeling of Heating, Ventilating, and Air Conditioning (HVAC) Systems: Experimental Applications Using Revit

    Science.gov (United States)

    2012-03-01

    Center, Construction Engineering Research Laboratory (ERDC-CERL) has developed a core life- cycle building information model ( BIM ) based on three...was to promote consistency and quality of content created for Building Information Models ( BIMs ) across various disciplines. The HVAC MVD was...MVD. 15. SUBJECT TERMS building information modeling ( BIM ), ontology, Army facilities, heating, ventilating, and air-conditioning (HVAC) systems

  14. HVAC systems in a field laboratory for indoor climate study

    DEFF Research Database (Denmark)

    Fang, Lei; Melikov, Arsen Krikor; Olesen, Bjarne W.

    2012-01-01

    This paper presents the design of a HVAC system for a field lab. The design integrated mixing ventilation, displacement ventilation, low impulse vertical ventilation, personalized ventilation, natural ventilation, hybrid ventilation, active chilled beams, radiant ceiling and floor, and heat...

  15. Review of Residential Low-Load HVAC Systems

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Scott A.; Thornton, Brian; Widder, Sarah H.

    2013-09-01

    In support of the U.S. Department of Energy’s (DOE’s) Building America Program, Pacific Northwest National Laboratory (PNNL) conducted an investigation to inventory commercially available HVAC technologies that are being installed in low-load homes. The first step in this investigation was to conduct a review of published literature to identify low-load HVAC technologies available in the United States and abroad, and document the findings of existing case studies that have evaluated the performance of the identified technologies. This report presents the findings of the literature review, identifies gaps in the literature or technical understanding that must be addressed before low-load HVAC technologies can be fully evaluated, and introduces PNNL’s planned research and analysis for this project to address identified gaps and potential future work on residential low-load HVAC systems.

  16. [Analysis and research on cleaning points of HVAC systems in public places].

    Science.gov (United States)

    Yang, Jiaolan; Han, Xu; Chen, Dongqing; Jin, Xin; Dai, Zizhu

    2010-03-01

    To analyze cleaning points of HVAC systems, and to provides scientific base for regulating the cleaning of HVAC systems. Based on the survey results on the cleaning situation of HVAC systems around China for the past three years, we analyzes the cleaning points of HVAC systems from various aspects, such as the major health risk factors of HVAC systems, the formulation strategy of the cleaning of HVAC systems, cleaning methods and acceptance points of the air ducts and the parts of HVAC systems, the onsite protection and individual protection, the waste treatment and the cleaning of the removed equipment, inspection of the cleaning results, video record, and the final acceptance of the cleaning. The analysis of the major health risk factors of HVAC systems and the formulation strategy of the cleaning of HVAC systems is given. The specific methods for cleaning the air ducts, machine units, air ports, coil pipes and the water cooling towers of HVAC systems, the acceptance points of HVAC systems and the requirements of the report on the final acceptance of the cleaning of HVAC systems are proposed. By the analysis of the points of the cleaning of HVAC systems and proposal of corresponding measures, this study provides the base for the scientific and regular launch of the cleaning of HVAC systems, a novel technology service, and lays a foundation for the revision of the existing cleaning regulations, which may generate technical and social benefits to some extent.

  17. HVAC systems in shopping centers as a utility business

    Energy Technology Data Exchange (ETDEWEB)

    Wolfert, J.E.

    1985-01-01

    Retail spaces in shopping centers have been noted for their low-cost and medium-quality HVAC systems. Typically, these systems are installed with minimal engineering and provided with less maintenance. There are, however, methods of providing higher quality HVAC systems for these retail spaces. One method is for the developer to provide a central plant type system and redistribute HVAC services for these spaces. The central plant system can redistribute chilled water, heated water, chilled air, heated air, tower water, electricity, or any other readily transportable energy source. With central type services, the economics are such that the individual retailer experiences no more overall cost but receives the benefits of a higher quality system. The developer has a larger investment but receives a reasonable return on this additional investment. The utilities now service a building that has a lower demand and a higher load factor. And society as a whole is presented with a facility that is considerably more energy efficient.

  18. Energy-Efficient Building HVAC Control Using Hybrid System LBMPC

    CERN Document Server

    Aswani, Anil; Taneja, Jay; Krioukov, Andrew; Culler, David; Tomlin, Claire

    2012-01-01

    Improving the energy-efficiency of heating, ventilation, and air-conditioning (HVAC) systems has the potential to realize large economic and societal benefits. This paper concerns the system identification of a hybrid system model of a building-wide HVAC system and its subsequent control using a hybrid system formulation of learning-based model predictive control (LBMPC). Here, the learning refers to model updates to the hybrid system model that incorporate the heating effects due to occupancy, solar effects, outside air temperature (OAT), and equipment, in addition to integrator dynamics inherently present in low-level control. Though we make significant modeling simplifications, our corresponding controller that uses this model is able to experimentally achieve a large reduction in energy usage without any degradations in occupant comfort. It is in this way that we justify the modeling simplifications that we have made. We conclude by presenting results from experiments on our building HVAC testbed, which s...

  19. Real-time supervision of building HVAC system performance

    Energy Technology Data Exchange (ETDEWEB)

    Djuric, Natasa

    2008-07-01

    This thesis presents techniques for improving building HVAC system performance in existing buildings generated using simulation-based tools and real data. Therefore, one of the aims has been to research the needs and possibilities to assess and improve building HVAC system performance. In addition, this thesis aims at an advanced utilization of building energy management system (BEMS) and the provision of useful information to building operators using simulation tools. Buildings are becoming more complex systems with many elements, while BEMS provide many data about the building systems. There are, however, many faults and issues in building performance, but there are legislative and cost-benefit forces induced by energy savings. Therefore, both BEMS and the computer-based tools have to be utilized more efficiently to improve building performance. The thesis consists of four main parts that can be read separately. The first part explains the term commissioning and the commissioning tool work principal based on literature reviews. The second part presents practical experiences and issues introduced through the work on this study. The third part deals with the computer-based tools application in design and operation. This part is divided into two chapters. The first deals with improvement in the design, and the second deals with the improvement in the control strategies. The last part of the thesis gives several rules for fault diagnosis developed using simulation tools. In addition, this part aims at the practical explanation of the faults in the building HVAC systems. The practical background for the thesis was obtained though two surveys. The first survey was carried out with the aim to find the commissioning targets in Norwegian building facilities. In that way, an overview of the most typical buildings, HVAC equipment, and their related problems was obtained. An on-site survey was carried out on an example building, which was beneficial for introducing the

  20. HVAC system simulation: use of condensed input data

    Energy Technology Data Exchange (ETDEWEB)

    Hanby, V.I.; Round, M. (Loughborough Univ. of Technology (United Kingdom))

    1992-01-01

    In many applications of HVAC system simulation, results are required over an extended time period. For example, long-term energy use predictions are frequently needed in a design context for comparison of alternative plant configurations and they are also necessary in plant optimisation studies where the objective function to be minimised contains energy-use terms. These are typical application areas which have involved the use of SPATS, a modular, steady-state HVAC plant simulation program developed at Loughborough University. The computation time involved in generating long-run performance figures has prompted an investigation of ways in which such results can be generated more quickly. SPATS was conceived and developed for performance simulation of HVAC systems at the design stage and although a dynamic zone model has recently been implemented, the main use of SPATS has been to examine the performance of mechanical systems and subsystems over a range of load conditions. (Author).

  1. Hybrid HVAC systems with chemical dehumidification for supermarket applications

    Energy Technology Data Exchange (ETDEWEB)

    Capozzoli, Alfonso; Mazzei, Pietro; Minichiello, Francesco; Palma, Daniele [DETEC, University of Naples Federico II, P.le Tecchio, 80, 80125 Naples (Italy)

    2006-06-15

    HVAC systems in supermarkets must assure both thermal comfort for occupants and suitable climatic conditions for refrigerated cases, which operate better with low ambient relative humidity (40-45%). Since open display cases substantially reduce sensible load and moderately reduce latent load, ambient sensible/total heat load ratio is less than usual. Thus, if dehumidification is carried out with a traditional cooling coil, over-sizing of the coil and re-heating of the treated air are necessary, with energy and economic waste. To offset these disadvantages, hybrid HVAC systems with chemical dehumidification may be employed. In this paper a case study is presented in which a traditional HVAC system is compared to hybrid systems with chemical dehumidification. Dynamic simulation codes (DOE and DesiCalc{sup (}TM)) and test reference year data (TRY), opportunely elaborated, have been used. Annual operating costs have been estimated and large savings have been obtained with hybrid systems. Considerable reduction of electric energy demand as well as better control of thermal-hygrometric conditions were noted. A simple payback of about 1 year has been obtained. Finally, a virtual retrofitting operation on 30% of the existing HVAC systems in Italian supermarkets has shown significant operating cost savings. [Author].

  2. D0 HVAC System Controls Evaluation of Upgrade Options

    Energy Technology Data Exchange (ETDEWEB)

    Markley, D.; Simon, P.; /Fermilab

    1998-05-05

    This engineering note documents three different options for upgrading the Dzero HVAC control system. All three options leave the current field hardware and field devices intact and upgrade the computer control hardware and software. Dzero will be heading into a physics run starting in 2000. This physics run could last several years. The Dzero HVAC system is an integral part of climate control and electronics cooling. The current HVAC control system is based upon a 1985 Johnson Controls System. In order to enter the next long-term physics run with a solid HVAC control system, the current control system needs to be upgraded. This proposal investigates three options: (1) Replacement to the next generation of Johnson Controls Hardware and Software with the Johnson Controls operator interface - FESS; (2) Replacement to the next generation of Johnson Controls Hardware and Software with the FIX32 Operator Interface - FESS/Dzero; and (3) Replacement with a commercially available Programmable Logic Controller (PLC) WITH THE FIX 32 Operator Interface - Dzero.

  3. System solution to improve energy efficiency of HVAC systems

    Science.gov (United States)

    Chretien, L.; Becerra, R.; Salts, N. P.; Groll, E. A.

    2017-08-01

    According to recent surveys, heating and air conditioning systems account for over 45% of the total energy usage in US households. Three main types of HVAC systems are available to homeowners: (1) fixed-speed systems, where the compressor cycles on and off to match the cooling load; (2) multi-speed (typically, two-speed) systems, where the compressor can operate at multiple cooling capacities, leading to reduced cycling; and (3) variable-speed systems, where the compressor speed is adjusted to match the cooling load of the household, thereby providing higher efficiency and comfort levels through better temperature and humidity control. While energy consumption could reduce significantly by adopting variable-speed compressor systems, the market penetration has been limited to less than 10% of the total HVAC units and a vast majority of systems installed in new construction remains single speed. A few reasons may explain this phenomenon such as the complexity of the electronic circuitry required to vary compressor speed as well as the associated system cost. This paper outlines a system solution to boost the Seasonal Energy Efficiency Rating (SEER) of a traditional single-speed unit through using a low power electronic converter that allows the compressor to operate at multiple low capacity settings and is disabled at high compressor speeds.

  4. Decentralized Optimization for a Novel Control Structure of HVAC System

    Directory of Open Access Journals (Sweden)

    Shiqiang Wang

    2016-01-01

    Full Text Available A decentralized control structure is introduced into the heating, ventilation, and air conditioning (HVAC system to solve the high maintenance and labor cost problem in actual engineering. Based on this new control system, a decentralized optimization method is presented for sensor fault repair and optimal group control of HVAC equipment. Convergence property of the novel method is theoretically analyzed considering both convex and nonconvex systems with constraints. In this decentralized control system, traditional device is fitted with a control chip such that it becomes a smart device. The smart device can communicate and operate collaboratively with the other devices to accomplish some designated tasks. The effectiveness of the presented method is verified by simulations and hardware tests.

  5. Control of noise - systems for compact HVAC units

    DEFF Research Database (Denmark)

    Pedersen, Steffen; Møller, Henrik

    2012-01-01

    This paper discusses noise control systems for implementation in compact HVAC units. The control of low-frequency noise presents different problems than at higher frequencies. This is mainly related to the long wavelength, which means that passive solutions require a significant volume of space......, often not available in compact HVAC units. Active control can provide attenuation over a significant frequency range, including low frequencies, while requiring a more limited space. While the concept of active noise control is simple, a number of limitations in the acoustical, electrical and control...... systems affect the performance of implementations. The source pressure and the impedance of a centrifugal fan were measured, and a number of configurations for noise control were investigated. The performance of a simple analogue feedback control was tested in a physical prototype. An adaptive digital...

  6. [Sick building syndrome and HVAC system: MVOC from air filters].

    Science.gov (United States)

    Schleibinger, H W; Wurm, D; Möritz, M; Böck, R; Rüden, H

    1997-08-01

    Growth and emissions of volatile metabolites of microorganisms on air filters are suspected to contribute to health complaints in ventilated rooms. To prove the microbiological production of volatile organic compounds (MVOC), concentrations of aldehydes and ketones were determined in two large HVAC systems. The in situ derivated aldehydes and ketones (as 2,4-dinitrophenyl-hydrazones) were analysed by HPLC and UV detection. The detection limit of each compound was 1 ppb (margin of error HVAC systems. First results show that the compounds formaldehyde, acetaldehyde and acetone could be detected before and after the filters. The concentrations of these VOC after the filters were significantly increased--as a mean over twenty measurements--, especially as far as filters made of glass fibre are concerned. However the found concentrations were low and mostly comparable to outdoor findings. In simultaneous laboratory experiments pieces of used filter material of one HVAC system and unused filter pieces (for blank values) were examined in small incubation chambers to investigate the possible production of MVOC. For the incubation a temperature of 20 degrees C and a relative humidity of 95% was chosen. In these experiments an almost identical spectrum of compounds (formaldehyde and acetone) was found as in the field measurements. The concentrations of these compounds were higher in the chambers with the used filter pieces. The concentration of acetone ranged up to almost 12 mg/m3.--As our field experiments correspond with our laboratory experiments, we assume that the microbial production of volatile organic compounds in HVAC systems under operating conditions is possible.

  7. Neural network based optimal control of HVAC&R systems

    Science.gov (United States)

    Ning, Min

    Heating, Ventilation, Air-Conditioning and Refrigeration (HVAC&R) systems have wide applications in providing a desired indoor environment for different types of buildings. It is well acknowledged that 30%-40% of the total energy generated is consumed by buildings and HVAC&R systems alone account for more than 50% of the building energy consumption. Low operational efficiency especially under partial load conditions and poor control are part of reasons for such high energy consumption. To improve energy efficiency, HVAC&R systems should be properly operated to maintain a comfortable and healthy indoor environment under dynamic ambient and indoor conditions with the least energy consumption. This research focuses on the optimal operation of HVAC&R systems. The optimization problem is formulated and solved to find the optimal set points for the chilled water supply temperature, discharge air temperature and AHU (air handling unit) fan static pressure such that the indoor environment is maintained with the least chiller and fan energy consumption. To achieve this objective, a dynamic system model is developed first to simulate the system behavior under different control schemes and operating conditions. The system model is modular in structure, which includes a water-cooled vapor compression chiller model and a two-zone VAV system model. A fuzzy-set based extended transformation approach is then applied to investigate the uncertainties of this model caused by uncertain parameters and the sensitivities of the control inputs with respect to the interested model outputs. A multi-layer feed forward neural network is constructed and trained in unsupervised mode to minimize the cost function which is comprised of overall energy cost and penalty cost when one or more constraints are violated. After training, the network is implemented as a supervisory controller to compute the optimal settings for the system. In order to implement the optimal set points predicted by the

  8. Design And Prototype Testing Of Economizer In HVAC Systems

    Directory of Open Access Journals (Sweden)

    Kongara Ajay

    2014-05-01

    Full Text Available Power, the word itself says to what extent the world is dependent on it. It may be fortunate or unfortunate, we are totally dependent on the power which is making the usage higher and higher which left us with energy crises and increasing costs of the energy usage. It’s time for Energy saving. These days, number of people in favour of the Energy saving has been increasing not to lessen the cost of usage but to let our future generations live with light and luxury. In this project, I have worked on the Energy conservation measures for HVAC that will save the energy to a little higher extent by designing an economizer. The theme of the project is to design a energy efficient economizer for HVAC Systems. A single unit of energy saving will yield in generation of two units of energy. My concern is to conserve energy and reduce usage by using ECMs where ever required.

  9. Filtration effectiveness of HVAC systems at near-roadway schools.

    Science.gov (United States)

    McCarthy, M C; Ludwig, J F; Brown, S G; Vaughn, D L; Roberts, P T

    2013-06-01

    Concern for the exposure of children attending schools located near busy roadways to toxic, traffic-related air pollutants has raised questions regarding the environmental benefits of advanced heating, ventilation, and air-conditioning (HVAC) filtration systems for near-road pollution. Levels of black carbon and gaseous pollutants were measured at three indoor classroom sites and at seven outdoor monitoring sites at Las Vegas schools. Initial HVAC filtration systems effected a 31-66% reduction in black carbon particle concentrations inside three schools compared with ambient air concentrations. After improved filtration systems were installed, black carbon particle concentrations were reduced by 74-97% inside three classrooms relative to ambient air concentrations. Average black carbon particle concentrations inside the schools with improved filtration systems were lower than typical ambient Las Vegas concentrations by 49-96%. Gaseous pollutants were higher indoors than outdoors. The higher indoor concentrations most likely originated at least partially from indoor sources, which were not targeted as part of this intervention. Recent literature has demonstrated adverse health effects in subjects exposed to ambient air near major roadways. Current smart growth planning and infill development often require that buildings such as schools are built near major roadways. Improving the filtration systems of a school's HVAC system was shown to decrease children's exposure to near-roadway diesel particulate matter. However, reducing exposure to the gas-phase air toxics, which primarily originated from indoor sources, may require multiple filter passes on recirculated air. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  10. Intelligent control of HVAC systems. Part II: perceptron performance analysis

    Directory of Open Access Journals (Sweden)

    Ioan URSU

    2013-09-01

    Full Text Available This is the second part of a paper on intelligent type control of Heating, Ventilating, and Air-Conditioning (HVAC systems. The whole study proposes a unified approach in the design of intelligent control for such systems, to ensure high energy efficiency and air quality improving. In the first part of the study it is considered as benchmark system a single thermal space HVAC system, for which it is assigned a mathematical model of the controlled system and a mathematical model(algorithm of intelligent control synthesis. The conception of the intelligent control is of switching type, between a simple neural network, a perceptron, which aims to decrease (optimize a cost index,and a fuzzy logic component, having supervisory antisaturating role for neuro-control. Based on numerical simulations, this Part II focuses on the analysis of system operation in the presence only ofthe neural control component. Working of the entire neuro-fuzzy system will be reported in a third part of the study.

  11. HVAC System Automatic Controls and Indoor Air Quality in Schools. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.

    Fans, motors, coils, and other control components enable a heating, ventilating, and air-conditioning (HVAC) system to function smoothly. An explanation of these control components and how they make school HVAC systems work is provided. Different systems may be compared by counting the number of controlled devices that are required. Control…

  12. HVAC System Automatic Controls and Indoor Air Quality in Schools. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.

    Fans, motors, coils, and other control components enable a heating, ventilating, and air-conditioning (HVAC) system to function smoothly. An explanation of these control components and how they make school HVAC systems work is provided. Different systems may be compared by counting the number of controlled devices that are required. Control…

  13. New Comparison of HVDC and HVAC Transmission system

    Directory of Open Access Journals (Sweden)

    Vahid Behravesh

    2012-06-01

    Full Text Available Alternating current (AC is the main driving force in the industries and residential areas, but for the long transmission line (more than 400 miles AC transmission is more expensive than that of direct current (DC. Technically, AC transmission line control is more complicated because of the frequency. DC transmission does not have these limitations, which has led to build long HVDC transmission lines over the last 40 years. HVDC technology made possible to transfer bulk power over long distances. This paper presents a comparative evaluation of HVDC and HVAC transmission systems .

  14. New HVAC control by system identification

    Energy Technology Data Exchange (ETDEWEB)

    So, A.T.P.; Chan, W.L.; Chow, T.T.; Tse, W.L. [City University of Hong Kong, Kowloon (Hong Kong)

    1995-12-01

    Modern air-conditioning systems for commercial buildings commonly employ the concept of a ``Central All-Air System`` and the VAV system in particular is widely used in Hong Kong, and other places around the world for energy conservation. In the lengthy wet summer season of Hong Kong centralised air-handling units (AHUs) dehumidify and cool down the appropriate mixture of return air and outdoor fresh air to feed a ducting network to various Variable Air Volume Boxes. A good controller for the AHUs is extremely desirable from both human comfort and energy saving points of view. In this paper, a simulation model for a practical air-handling system is presented. Its behaviour under a conventional system of PID controllers is studied. A new controller based on system identification is developed where input and actuating variables are incorporated into a system identification model which can predict the new system status based on past records and suggest the optimal control actions. Computer simulation has proved that such a system identification based controller is superior to the conventional PID controller from at least the following three aspects: adaptation to system change, response rate and energy conservation. (author)

  15. Protecting HVAC systems from bio-terrorism.

    Science.gov (United States)

    Arterburn, Tom

    2003-01-01

    The FBI, in the wake of the September 11 attacks, issued an advisory to state and local law enforcement authorities and the public asking to remain especially alert to any unusual activities around ventilation systems. It noted that while the Bureau possessed no specific threats regarding the release of toxic chemicals into air handling systems, building owners and managers should be well-aware of the potential for contamination of such systems. This article presents recommendations of air-handling experts and associations for operators to consider.

  16. Flexible HVAC System for Lab or Classroom.

    Science.gov (United States)

    Friedan, Jonathan

    2001-01-01

    Discusses an effort to design a heating, ventilation, and air conditioning system flexible enough to accommodate an easy conversion of classrooms to laboratories and dry labs to wet labs. The design's energy efficiency and operations and maintenance are examined. (GR)

  17. Flexible HVAC System for Lab or Classroom.

    Science.gov (United States)

    Friedan, Jonathan

    2001-01-01

    Discusses an effort to design a heating, ventilation, and air conditioning system flexible enough to accommodate an easy conversion of classrooms to laboratories and dry labs to wet labs. The design's energy efficiency and operations and maintenance are examined. (GR)

  18. Thermal Components Boost Performance of HVAC Systems

    Science.gov (United States)

    2012-01-01

    As the International Space Station (ISS) travels 17,500 miles per hour, normal is having a constant sensation of free-falling. Normal is no rain, but an extreme amount of shine.with temperatures reaching 250 F when facing the Sun. Thanks to a number of advanced control systems onboard the ISS, however, the interior of the station remains a cool, comfortable, normal environment where astronauts can live and work for extended periods of time. There are two main control systems on the ISS that make it possible for humans to survive in space: the Thermal Control System (TCS) and the Environmental Control and Life Support system. These intricate assemblies work together to supply water and oxygen, regulate temperature and pressure, maintain air quality, and manage waste. Through artificial means, these systems create a habitable environment for the space station s crew. The TCS constantly works to regulate the temperature not only for astronauts, but for the critical instruments and machines inside the spacecraft as well. To do its job, the TCS encompasses several components and systems both inside and outside of the ISS. Inside the spacecraft, a liquid heat-exchange process mechanically pumps fluids in closed-loop circuits to collect, transport, and reject heat. Outside the ISS, an external system circulates anhydrous ammonia to transport heat and cool equipment, and radiators release the heat into space. Over the years, NASA has worked with a variety of partners.public and private, national and international. to develop and refine the most complex thermal control systems ever built for spacecraft, including the one on the ISS.

  19. Wireless Demand Response Controls for HVAC Systems

    Energy Technology Data Exchange (ETDEWEB)

    Federspiel, Clifford

    2009-06-30

    The objectives of this scoping study were to develop and test control software and wireless hardware that could enable closed-loop, zone-temperature-based demand response in buildings that have either pneumatic controls or legacy digital controls that cannot be used as part of a demand response automation system. We designed a SOAP client that is compatible with the Demand Response Automation Server (DRAS) being used by the IOUs in California for their CPP program, design the DR control software, investigated the use of cellular routers for connecting to the DRAS, and tested the wireless DR system with an emulator running a calibrated model of a working building. The results show that the wireless DR system can shed approximately 1.5 Watts per design CFM on the design day in a hot, inland climate in California while keeping temperatures within the limits of ASHRAE Standard 55: Thermal Environmental Conditions for Human Occupancy.

  20. Considerations to Prevent Growth and Spread of Legionella in HVAC Systems.

    Science.gov (United States)

    Coleman, Jeff

    1998-01-01

    Discusses the threat posed by the Legionnaire's Disease bacterium and the germ's ability to thrive in heating, ventilating, and air conditioning (HVAC) systems, especially in standing water. Describes ways to minimize disease risk through HVAC system design (such as locating cooling towers away from air intakes) and ways to maintain a clean…

  1. Air Cleaning Devices for HVAC Supply Systems in Schools. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.

    Guidelines for maintaining indoor air quality in schools with HVAC air cleaning systems are provided in this document. Information is offered on the importance of air cleaning, sources of air contaminants and indoor pollutants, types of air cleaners and particulate filters used in central HVAC systems, vapor and gas removal, and performance…

  2. Considerations to Prevent Growth and Spread of Legionella in HVAC Systems.

    Science.gov (United States)

    Coleman, Jeff

    1998-01-01

    Discusses the threat posed by the Legionnaire's Disease bacterium and the germ's ability to thrive in heating, ventilating, and air conditioning (HVAC) systems, especially in standing water. Describes ways to minimize disease risk through HVAC system design (such as locating cooling towers away from air intakes) and ways to maintain a clean…

  3. Theoretical analysis of HVAC duct hanger systems

    Science.gov (United States)

    Miller, R. D.

    1987-01-01

    Several methods are presented which, together, may be used in the analysis of duct hanger systems over a wide range of frequencies. The finite element method (FEM) and component mode synthesis (CMS) method are used for low- to mid-frequency range computations and have been shown to yield reasonably close results. The statistical energy analysis (SEA) method yields predictions which agree with the CMS results for the 800 to 1000 Hz range provided that a sufficient number of modes participate. The CMS approach has been shown to yield valuable insight into the mid-frequency range of the analysis. It has been demonstrated that it is possible to conduct an analysis of a duct/hanger system in a cost-effective way for a wide frequency range, using several methods which overlap for several frequency bands.

  4. Modeling and Measurement Constraints in Fault Diagnostics for HVAC Systems

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Massieh; Auslander, David M.; Bartlett, Peter L.; Haves, Philip; Sohn, Michael D.

    2010-05-30

    Many studies have shown that energy savings of five to fifteen percent are achievable in commercial buildings by detecting and correcting building faults, and optimizing building control systems. However, in spite of good progress in developing tools for determining HVAC diagnostics, methods to detect faults in HVAC systems are still generally undeveloped. Most approaches use numerical filtering or parameter estimation methods to compare data from energy meters and building sensors to predictions from mathematical or statistical models. They are effective when models are relatively accurate and data contain few errors. In this paper, we address the case where models are imperfect and data are variable, uncertain, and can contain error. We apply a Bayesian updating approach that is systematic in managing and accounting for most forms of model and data errors. The proposed method uses both knowledge of first principle modeling and empirical results to analyze the system performance within the boundaries defined by practical constraints. We demonstrate the approach by detecting faults in commercial building air handling units. We find that the limitations that exist in air handling unit diagnostics due to practical constraints can generally be effectively addressed through the proposed approach.

  5. Case study field evaluation of a systems approach to retrofitting a residential HVAC system

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S.; McWiliams, Jennifer A.; Konopacki, Steven J.

    2003-09-01

    This case study focusing on a residence in northern California was undertaken as a demonstration of the potential of a systems approach to HVAC retrofits. The systems approach means that other retrofits that can affect the HVAC system are also considered. For example, added building envelope insulation reduces building loads so that smaller capacity HVAC system can be used. Secondly, we wanted to examine the practical issues and interactions with contractors and code officials required to accomplish the systems approach because it represents a departure from current practice. We identified problems in the processes of communication and installation of the retrofit that led to compromises in the final energy efficiency of the HVAC system. These issues must be overcome in order for HVAC retrofits to deliver the increased performance that they promise. The experience gained in this case study was used to optimize best practices guidelines for contractors (Walker 2003) that include building diagnostics and checklists as tools to assist in ensuring the energy efficiency of ''house as a system'' HVAC retrofits. The best practices guidelines proved to be an excellent tool for evaluating the eight existing homes in this study, and we received positive feedback from many potential users who reviewed and used them. In addition, we were able to substantially improve the energy efficiency of the retrofitted case study house by adding envelope insulation, a more efficient furnace and air conditioner, an economizer and by reducing duct leakage.

  6. Case study field evaluation of a systems approach to retrofitting a residential HVAC system

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S.; McWiliams, Jennifer A.; Konopacki, Steven J.

    2003-09-01

    This case study focusing on a residence in northern California was undertaken as a demonstration of the potential of a systems approach to HVAC retrofits. The systems approach means that other retrofits that can affect the HVAC system are also considered. For example, added building envelope insulation reduces building loads so that smaller capacity HVAC system can be used. Secondly, we wanted to examine the practical issues and interactions with contractors and code officials required to accomplish the systems approach because it represents a departure from current practice. We identified problems in the processes of communication and installation of the retrofit that led to compromises in the final energy efficiency of the HVAC system. These issues must be overcome in order for HVAC retrofits to deliver the increased performance that they promise. The experience gained in this case study was used to optimize best practices guidelines for contractors (Walker 2003) that include building diagnostics and checklists as tools to assist in ensuring the energy efficiency of ''house as a system'' HVAC retrofits. The best practices guidelines proved to be an excellent tool for evaluating the eight existing homes in this study, and we received positive feedback from many potential users who reviewed and used them. In addition, we were able to substantially improve the energy efficiency of the retrofitted case study house by adding envelope insulation, a more efficient furnace and air conditioner, an economizer and by reducing duct leakage.

  7. Airside HVAC BESTEST: HVAC Air-Distribution System Model Test Cases for ASHRAE Standard 140

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, Ronald [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Neymark, Joel [J. Neymark & Associates; Kennedy, Mike D. [Mike D. Kennedy, Inc.; Gall, J. [AAON, Inc.; Henninger, R. [GARD Analytics, Inc.; Hong, T. [Lawrence Berkeley National Laboratory; Knebel, D. [AAON, Inc.; McDowell, T. [Thermal Energy System Specialists, LLC; Witte, M. [GARD Analytics, Inc.

    2017-08-07

    This paper summarizes recent work to develop new airside HVAC equipment model analytical verification test cases for ANSI/ASHRAE Standard 140, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs. The analytical verification test method allows comparison of simulation results from a wide variety of building energy simulation programs with quasi-analytical solutions, further described below. Standard 140 is widely cited for evaluating software for use with performance-path energy efficiency analysis, in conjunction with well-known energy-efficiency standards including ASHRAE Standard 90.1, the International Energy Conservation Code, and other international standards. Airside HVAC Equipment is a common area of modelling not previously explicitly tested by Standard 140. Integration of the completed test suite into Standard 140 is in progress.

  8. T.A.B. of HVAC System in IMEF

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Youl; Choo, Y. S.; Choung, W. M.; You, K. S.; Hong, K. P

    2005-12-15

    T.A.B of the HVAC system in IMEF is that the adjustment for satisfying the design requirement is done through the review of documents related to the its design and the measurement using the apparatus. Doing T.A.B., the comfortable indoor environments and the negative pressure among the areas is remained, and the air flows to the more contaminated area. T.A.B. is an abbreviation of Testing, Adjusting and Balancing. In this job, a quantitative judgment of each equipments' performance, a proper adjustment of the volume of airflow and water in terminal equipment and a proportional distribution of flow rate in the distribution system(main duct, branch duct and terminal) based on design values have been performed. After finishing these procedures, the system is inspected and adjusted so that all air conditioning system in IMEF building performs its best capacity as mentioned in design requirements.

  9. Co-simulation of innovative integrated HVAC systems in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Trcka, Marija; Hensena, Jan L.M.; Wetter, Michael

    2010-06-21

    Integrated performance simulation of buildings HVAC systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation, as an integrated approach to simulation. This article elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in the here described co-simulation prototype. The prototype is validated with the results obtained from the traditional simulation approach. It is further used in a proof-of-concept case study to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling time step.

  10. RELIABILITY ANALYSIS OF THE ELECTRICAL POWER DISTRIBUTION SYSTEM TO SELECTED PORTIONS OF THE NUCLEAR HVAC SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    N. Ramirez

    2004-12-16

    A design requirement probability of 0.01 or less in a 4-hour period ensures that the nuclear heating, ventilation, and air-conditioning (HVAC) system in the primary confinement areas of the Dry Transfer Facilities (DTFs) and Fuel Handling Facility (FHF) is working during a Category 1 drop event involving commercial spent nuclear fuel (CSNF) assemblies (BSC 2004a , Section 5.1.1.48). This corresponds to an hourly HVAC failure rate of 2.5E-3 per hour or less, which is contributed to by two dominant causes: equipment failure and loss of electrical power. Meeting this minimum threshold ensures that a Category 1 initiating event followed by the failure of HVAC is a Category 2 event sequence. The two causes for the loss of electrical power include the loss of offsite power and the loss of onsite power distribution. Thus, in order to meet the threshold requirement aforementioned, the failure rate of mechanical equipment, loss of offsite power, and loss of onsite power distribution must be less than or equal to 2.5E-3 per hour for the nuclear HVAC system in the primary confinement areas of the DTFs and FHF. The loss of offsite power occurs at a frequency of 1.1E-5 per hour (BSC 2004a, Section 5.1.1.48). The purpose of this analysis is to determine the probability of occurrence of the unavailability of the nuclear HVAC system in the primary confinement areas of the DTFs and FHF due to loss of electrical power. In addition, this analysis provides insights on the contribution to the unavailability of the HVAC system due to equipment failure. The scope of this analysis is limited to finding the frequency of loss of electrical power to the nuclear HVAC system in the primary confinement areas of the DTFs and FHF.

  11. Space HVAC systems - a manual. Vol. 3. Constructional elements. Handbuch der Klimatechnik. Bd. 3. Bauelemente

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    Vol. 3 of this series describes the design, function and fundamentals of calculation of air conditioning system elements and gives hints on their fields of application. Subjects: Heat transfer media; air moisturizers and dehumidifiers and their application in HVAC systems; refrigerators; air filters; ducts and auxiliary elements; fans; air conditioners; measuring methods and equipment for HVAC systems; fire protection and mechanical smoke prevention; clean room technology. (HWJ).

  12. Determination of k-factors of HVAC system components using measurement and CFD modelling

    OpenAIRE

    Smith, Shaun J.

    1998-01-01

    This thesis conforms conventional and advanced experimental techniques for the measurement of and mathematical prediction of velocity pressure-loss factors (kfactors) for fittings used in heating, ventilation and air-conditioning (HVAC) systems. After an extensive study of different tracer-gas experimental techniques, the constant injection method is applied to various duct fittings on a small scale HVAC system situated in a laboratory. The results are compared with those of experiments perfo...

  13. Small Business Voucher CRADA Report: Natural Gas Powered HVAC System for Commercial and Residential Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Betts, Daniel [Be Power Tech, Deerfield Beach, FL (United States); Ally, Moonis Raza [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mudiraj, Shyam [Be Power Tech, Deerfield Beach, FL (United States); Tilghman, Matthew [Be Power Tech, Deerfield Beach, FL (United States); Graham, Matthew [Be Power Tech, Deerfield Beach, FL (United States)

    2017-04-30

    Be Power Tech is commercializing BeCool, the first integrated electricity-producing heating, ventilation, and air conditioning (HVAC) system using a non-vapor compression cycle (VCC), packaged rooftop HVAC unit that also produces base-load electricity, heating, ventilation, and air conditioning. BeCool is a distributed energy resource with energy storage that eliminates the tremendous peak electricity demand associated with commonly used electricity-powered vapor compression air conditioning systems.

  14. Comparative Analysis of HVAC System Based on Life Cycle Cost Analysis

    Directory of Open Access Journals (Sweden)

    Jignesh M. Barot

    2014-07-01

    Full Text Available A heating, ventilating, and air conditioning (HVAC system is designed to satisfy the environmental requirements of comfort or a process, in a specific building or portion of a building and in a particular geographic locale. Efficient design of heating, ventilating and air-conditioning (HVAC systems is a primary concern in building projects. The objectives of the HVAC system design are to provide a thermal comfort, good indoor quality and energy conservation. For the typical commercial building projects, it is not difficult to acquire the reference settings for efficient operation. However, for some special projects, due to the specific design and control of the HVAC system, conventional settings may not be necessarily energy-efficient in daily operation. The HVAC system design and equipment selection for a commercial building (376 TR is included as a case study in this paper. The outcomes of this paper are efficient design of HVAC system with minimum energy consumption and equipment selection based on operating and life cycle cost analysis.

  15. Comparative Energy and Cost Analysis Between Conventional HVAC Systems and Geothermal Heat Pump Systems

    Science.gov (United States)

    2007-11-02

    heat pump (GSHP) relative to conventional heating ventilation and air conditioning (HVAC) systems: air-source heat pumps (ASHP), air-cooled air conditioning with either natural gas, fuel oil, or liquid petroleum gas furnaces, or with electrical resistance heating. The Monte Carlo simulation is performed for a standard commercial office building within each of the 48 continental states. Regardless of the conventional HVAC system chosen, the simulation shows that for each state the GSHP has the highest probability of using less energy and having a lower operating and life

  16. Design and Implementation of Energy Efficiency in HVAC Systems Based on Robust PID Control for Industrial Applications

    OpenAIRE

    Muharrem Imal

    2015-01-01

    Energy efficiency in heating, ventilating, and air-conditioning (HVAC) systems is a primary concern in process projects, since the energy consumption has the highest percentage in HVAC for all processes. Without sacrifice of thermal comfort, to reset the suitable operating parameters, such as the humidity and air temperature, would have energy saving with immediate effect. In this paper, the simulation-optimization approach described the effective energy efficiency for HVAC systems which are ...

  17. A new HVAC system based on cogeneration by an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M [Instituto di Ingegneria Gestionale, Universita di Padova, Vicenza (Italy); Longo, G.A.; Romagnoni, P.C. [Istituto di Fisica Technica, Universita di Padova, Padova (Italy)

    1997-06-01

    A new HVAC system is proposed and studied. The plant consists of a reciprocating internal combustion gas engine, producing electrical energy with heat recovery from the jacket water heat and the exhaust. The electricity serves lighting, emf for the building and individual room reversible air-water heat pumps that satisfy mainly sensible cooling and a fraction of the winter heating load. An open cycle absorption system which treats the primary air meets the summer latent load and year round ventilation requirements. In winter the system operates as an open cycle heat pump. The regeneration of the sorbent is obtained by the internal combustion engine heat recovery. The proposed system is analyzed comparing its performance with a traditional plant both in summer and winter mode. 8 refs.

  18. Review on the HVAC System Modeling Types and the Shortcomings of Their Application

    Directory of Open Access Journals (Sweden)

    Raad Z. Homod

    2013-01-01

    Full Text Available The modeling of the heating, ventilation, and air conditioning (HVAC system is a prominent topic because of its relationship with energy savings and environmental, economical, and technological issues. The modeling of the HVAC system is concerned with the indoor thermal sensation, which is related to the modeling of building, air handling unit (AHU equipments, and indoor thermal processes. Until now, many HVAC system modeling approaches are made available, and the techniques have become quite mature. But there are some shortcomings in application and integration methods for the different types of the HVAC model. The application and integration processes will act to accumulate the defective characteristics for both AHU equipments and building models such as nonlinear, pure lag time, high thermal inertia, uncertain disturbance factors, large-scale systems, and constraints. This paper shows types of the HVAC model and the advantages and disadvantages for each application of them, and it finds out that the gray-box type is the best one to represent the indoor thermal comfort. But its application fails at the integration method where its response deviated to unreal behavior.

  19. Selecting HVAC Systems for Schools To Balance the Needs for Indoor Air Quality, Energy Conservation and Maintenance. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.; Kunz, Walter S., Jr.

    Although poor air quality in a school can have multiple causes, the heating, ventilating, and air-conditioning (HVAC) system plays a major role. Suggestions that architects, facilities managers, school board members, and administrators can use in selecting HVAC systems are discussed. Focus is on the performance criteria for classroom systems, and…

  20. Selecting HVAC Systems for Schools To Balance the Needs for Indoor Air Quality, Energy Conservation and Maintenance. Technical Bulletin.

    Science.gov (United States)

    Wheeler, Arthur E.; Kunz, Walter S., Jr.

    Although poor air quality in a school can have multiple causes, the heating, ventilating, and air-conditioning (HVAC) system plays a major role. Suggestions that architects, facilities managers, school board members, and administrators can use in selecting HVAC systems are discussed. Focus is on the performance criteria for classroom systems, and…

  1. HVAC cable systems with forced water cooling for wind energy transmission

    Energy Technology Data Exchange (ETDEWEB)

    Brakelmann, Heinrich; Zhang, Dongping [Duisburg-Essen Univ., Duisburg (DE). Dept. Energy Transport and Storage (ETS)

    2008-07-01

    This paper presents a solution for an efficient wind energy transmission onshore: HVAC cable system with forced water cooling, which provides a substantial increase of the cable ampacity without any modification of the cable construction and design. This work shows the projecting and planning of such HVAC cable systems in combination with a cooling system, especially considering the faulty (n-1)-case. The efficiency utilizing the short-term load capacity of the cable systems transmitting wind energy is shown by computations provided by specialized and adapted FEM (Finite Element Method) software. (orig.)

  2. Plutonium Finishing Plant (PFP) HVAC System Component Index

    Energy Technology Data Exchange (ETDEWEB)

    DIAZ, E.N.; DICK, J.D.

    2000-07-26

    This document lists safety class (SC) and safety significant (SS) components for the Heating Ventilation Air Conditioning (HVAC) and specifies the critical characteristics for Commercial Grade Items (CGI), as required by HNF-PRO-268 and HNF-PRO-1819. These are the minimum specifications that the equipment must meet in order to properly perform its safety function. There may be several manufacturers or models that meet the critical characteristics for any one item.

  3. Integrated high efficiency blower apparatus for HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoyue; Weigman, Herman; Wang, Shixiao

    2007-07-24

    An integrated centrifugal blower wheel for a heating, ventilation and air conditioning (HVAC) blower unit includes a first blade support, a second blade support, and a plurality of S-shaped blades disposed between the first and second blade supports, wherein each of the S-shaped blades has a trailing edge bent in a forward direction with respect to a defined direction of rotation of the wheel.

  4. Integrated high efficiency blower apparatus for HVAC systems

    Science.gov (United States)

    Liu, Xiaoyue; Weigman, Herman; Wang, Shixiao

    2007-07-24

    An integrated centrifugal blower wheel for a heating, ventilation and air conditioning (HVAC) blower unit includes a first blade support, a second blade support, and a plurality of S-shaped blades disposed between the first and second blade supports, wherein each of the S-shaped blades has a trailing edge bent in a forward direction with respect to a defined direction of rotation of the wheel.

  5. RADON MITIGATION IN SCHOOLS: HVAC SYTEMS IN SCHOOLS TEND TO HAVE A GREATER IMPACT ON RADON LEVELS THAN HVAC SYSTEMS IN HOMES

    Science.gov (United States)

    The first part of this two-part paper discusses radon entry into schools, radon mitigation approaches for schools, and school characteristics (e.g., heating, ventilation, and air conditioing -- HVAC-- system design and operationg) that influence radon entry and mitigation system ...

  6. RADON MITIGATION IN SCHOOLS: HVAC SYTEMS IN SCHOOLS TEND TO HAVE A GREATER IMPACT ON RADON LEVELS THAN HVAC SYSTEMS IN HOMES

    Science.gov (United States)

    The first part of this two-part paper discusses radon entry into schools, radon mitigation approaches for schools, and school characteristics (e.g., heating, ventilation, and air conditioing -- HVAC-- system design and operationg) that influence radon entry and mitigation system ...

  7. Predictive functional control based on fuzzy T-S model for HVAC systems temperature control

    Institute of Scientific and Technical Information of China (English)

    Hongli L(U); Lei JIA; Shulan KONG; Zhaosheng ZHANG

    2007-01-01

    In heating,ventilating and air-conditioning(HVAC)systems,there exist severe nonlinearity,time-varying nature,disturbances and uncertainties.A new predictive functional control based on Takagi-Sugeno(T-S)fuzzy model was proposed to control HVAC systems.The T-S fuzzy model of stabilized controlled process was obtained using the least squares method,then on the basis of global linear predictive model from T-S fuzzy model,the process was controlled by the predictive functional controller.Especially the feedback regulation part was developed to compensate uncertainties of fuzzy predictive model.Finally simulation test results in HVAC systems control applications showed that the proposed fuzzy model predictive functional control improves tracking effect and robustness.Compared with the conventional PID controller,this control strategy has the advantages of less overshoot and shorter setting time,etc.

  8. Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

    Science.gov (United States)

    Simmons, R B; Crow, S A

    1995-01-01

    New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

  9. Power Flow Analysis of HVAC and HVDC Transmission Systems for Offshore WindParks

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Castro, Rui

    2009-01-01

    As the onshore wind resource is running shorter, wind power promoters are paying attention to the offshore resources. As in most cases there is no load offshore, wind power must be transmitted to the main land. To do so, two options are available: HVAC and HVDC transmission systems. In this paper...... that HVAC solution is limited by the distance to shore and by the wind transmitted power. HVDC options do not show these limitations, but are more expensive and more delicate to deal with, because there is a lack of operational experience, so far....

  10. 'Consolidation' of HVAC and cooling systems at CERN

    CERN Document Server

    Inigo-Golfin, J; Pepinster, P; CERN. Geneva. TS Department

    2008-01-01

    A â€ワconsolidation” of installations after they have reached the end of their predetermined life-time is part of the life cycle of industrial installations, regardless how well maintained they are. The â€ワconsolidation” plan might cover the replacement of obsolete equipment, partial refurbishment, the work requested to comply with new standards and applicable rules (environmental aspects) until the complete replacement of the whole installation. This â€ワconsolidation” process is all the more critical since the installation dates of the existing cooling and HVAC equipment at CERN spans over a period of 50 years and â€ワconsolidation” in the past has been not been systematic, being most of the time associated with new projects. This paper describes the reasons behind the recent â€ワconsolidation” requests for cooling and HVAC equipment both for the accelerators backbone and in tertiary buildings. A criticality analysis is given, based on the criteria laid down in the p...

  11. AIRLESS, a European project on HVAC systems: Project programme and current status

    NARCIS (Netherlands)

    Bluyssen, P.M.; Björkroth, M.; Müller, B.; Oliveira Fernandes, E. de; Clausen, G.H.; Molina, J.L.; Roulet, C.A.

    1999-01-01

    In the beginning of 1998 a three year European project, AIRLESS, was started to develop strategies, principles and protocols to improve and control the performance of HVAC-systems and its components for incorporation in codes and guidelines. Twelve institutes, universities and companies from seven E

  12. Application of black-box models to HVAC systems for fault detection

    NARCIS (Netherlands)

    Peitsman, H.C.; Bakker, V.E.

    1996-01-01

    This paper describes the application of black-box models for fault detection and diagnosis (FDD) in heating, ventilat-ing, and air-conditioning (HVAC) systems. In this study, mul-tiple-input/single-output (MISO) ARX models and artificial neural network (ANN) models are used. The ARX models are exami

  13. Assessment of microbiological indoor air quality in an Italian office building equipped with an HVAC system.

    Science.gov (United States)

    Bonetta, Sa; Bonetta, Si; Mosso, S; Sampò, S; Carraro, E

    2010-02-01

    The purpose of this study was to evaluate the level and composition of bacteria and fungi in the indoor air of an Italian office building equipped with a heating, ventilation and air conditioning (HVAC) system. Airborne bacteria and fungi were collected in three open-space offices during different seasons. The microbial levels in the outdoor air, supply air diffusers, fan coil air flow and air treatment unit humidification water tank were used to evaluate the influence of the HVAC system on indoor air quality (IAQ). A medium-low level of bacterial contamination (50-500 CFU/m(3)) was found in indoor air. Staphylococcus and Micrococcus were the most commonly found genera, probably due to human presence. A high fungal concentration was measured due to a flood that occurred during the winter. The indoor seasonal distribution of fungal genera was related to the fungal outdoor distribution. Significant seasonal and daily variation in airborne microorganisms was found, underlining a relationship with the frequency of HVAC system switching on/off. The results of this monitoring highlight the role of the HVAC system on IAQ and could be useful to better characterise bacterial and fungal population in the indoor air of office buildings.

  14. Application of black-box models to HVAC systems for fault detection

    NARCIS (Netherlands)

    Peitsman, H.C.; Bakker, V.E.

    1996-01-01

    This paper describes the application of black-box models for fault detection and diagnosis (FDD) in heating, ventilat-ing, and air-conditioning (HVAC) systems. In this study, mul-tiple-input/single-output (MISO) ARX models and artificial neural network (ANN) models are used. The ARX models are

  15. Towards a framework for selection of supervisory control for commercial buildings: HVAC system energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Ramachandran, Thiagarajan; Kundu, Soumya; Chen, Yan; Vrabie, Draguna L.

    2017-07-03

    This paper develops and utilizes an optimization based framework to investigate the maximal energy efficiency potentially attainable by HVAC system operation in a non-predictive context. Performance is evaluated relative to the existing state of the art set-point reset strategies. The expected efficiency increase driven by operation constraints relaxations is evaluated.

  16. AIRLESS, a European project on HVAC systems: Project programme and current status

    NARCIS (Netherlands)

    Bluyssen, P.M.; Björkroth, M.; Müller, B.; Oliveira Fernandes, E. de; Clausen, G.H.; Molina, J.L.; Roulet, C.A.

    1999-01-01

    In the beginning of 1998 a three year European project, AIRLESS, was started to develop strategies, principles and protocols to improve and control the performance of HVAC-systems and its components for incorporation in codes and guidelines. Twelve institutes, universities and companies from seven

  17. Consistency in Distributed Systems

    OpenAIRE

    Kemme, Bettina; Ramalingam, Ganesan; Schiper, André; Shapiro, Marc; Vaswani, Kapil

    2013-01-01

    International audience; In distributed systems, there exists a fundamental trade-off between data consistency, availability, and the ability to tolerate failures. This trade-off has significant implications on the design of the entire distributed computing infrastructure such as storage systems, compilers and runtimes, application development frameworks and programming languages. Unfortunately, it also has significant, and poorly understood, implications for the designers and developers of en...

  18. Analysis on energy saving potential of integrated supermarket HVAC and refrigeration systems using multiple subcoolers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); China R and D Center, Carrier Corporation, No. 3239 Shen Jiang Road, Shanghai 201206 (China); Zhang, Chun-Lu [China R and D Center, Carrier Corporation, No. 3239 Shen Jiang Road, Shanghai 201206 (China)

    2010-02-15

    The paper presents a model-based analysis on the energy saving potential of supermarket HVAC (heating, ventilating, and air-conditioning) and refrigeration systems using multiple subcoolers among the high-temperature HVAC system, the medium-temperature refrigeration system, and the low-temperature refrigeration system. The principle of energy reduction is to have the higher COP (coefficient of performance) system generate more cooling capacity to increase the cooling capacity or reduce the power consumption of the lower COP system. The subcooler could be placed between the medium-temperature and low-temperature systems, between the high-temperature and medium-temperature systems, and between the high-temperature and low-temperature systems. All integration scenarios of adding one, two and three subcoolers have been investigated. The energy saving potential varies with the load ratio between high-, medium- and low-temperature systems, COP of three systems, and the ''on-off'' duty time of HVAC system. The optimal sequence of adding subcoolers is also proposed. (author)

  19. Portable refrigerant charge meter and method for determining the actual refrigerant charge in HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming; Abdelaziz, Omar; LaClair, Tim L.

    2017-08-08

    A refrigerant charge meter and a method for determining the actual refrigerant charge in HVAC systems are described. The meter includes means for determining an optimum refrigerant charge from system subcooling and system component parameters. The meter also includes means for determining the ratio of the actual refrigerant charge to the optimum refrigerant charge. Finally, the meter includes means for determining the actual refrigerant charge from the optimum refrigerant charge and the ratio of the actual refrigerant charge to the optimum refrigerant charge.

  20. Control of Variable-Speed Pressurization Fan for an Offshore HVAC System

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Pedersen, Simon; Løhndorf, Petar Durdevic

    2014-01-01

    of the inlet channel in the considered Heating Ventilation and Air-Condition (HVAC) system, or the pressurization system located inside the inlet channel, or both of them in a coordinated way. A Model-Predictive Control (MPC) solution to control the inlet throttle has been proposed in our previous work....... This paper proposes a set of control solutions to regulate the variablespeed pressurization fan system such that the energy efficiency of the considered HVAC system can be explicitly considered. A combined feed-forward with a PI-based feedback control solution, and a MPC solution are proposed based...... on derived simple system models. Some preliminary simulation results exhibit that both control solutions can keep the indoor pressure and the air circulation in a very satisfactory and robust manner, even subject to the presence of severe disturbances....

  1. Comparative guide to emerging diagnostic tools for large commercial HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Hannah; Piette, Mary Ann

    2001-05-01

    This guide compares emerging diagnostic software tools that aid detection and diagnosis of operational problems for large HVAC systems. We have evaluated six tools for use with energy management control system (EMCS) or other monitoring data. The diagnostic tools summarize relevant performance metrics, display plots for manual analysis, and perform automated diagnostic procedures. Our comparative analysis presents nine summary tables with supporting explanatory text and includes sample diagnostic screens for each tool.

  2. Saving electricity in HVAC systems. Elektrizitaet sparen in Heizungs-, Lueftungs-, Klima- und Kaelteanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Hochstrasser, W.

    1993-03-01

    The SIA initiated the recommendation SIA 380/4, ''Electrical energy in building construction'' which contains information on energy conservation. As an example, the field of HVAC systems is discussed. In this field, electrical energy is required especially for the following applications: Blower drives, refrigerating compressor drives, hot and cold water pumps, oil and gas burners, control systems, air heaters, and electric moisturizers. Energy-saving alternatives are presented in each case. (orig.)

  3. Estimating occupant satisfaction of HVAC system noise using quality assessment index.

    Science.gov (United States)

    Forouharmajd, Farhad; Nassiri, Parvin; Monazzam, Mohammad R; Yazdchi, Mohammadreza

    2012-01-01

    Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC) systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans) uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC) method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF) sound and low-frequency (LF) sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI) of 9.8. This concludes the QAI is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave bands exceed 65

  4. Estimating occupant satisfaction of HVAC system noise using quality assessment index

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2012-01-01

    Full Text Available Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF sound and low-frequency (LF sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI of 9.8. This concludes the QAI is useful in estimating an occupant′s probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave

  5. Power Flow Analysis of HVAC and HVDC Transmission Systems for Offshore WindParks

    DEFF Research Database (Denmark)

    da Silva, Filipe Miguel Faria; Castro, Rui

    2009-01-01

    , the two options are analysed from a power flow point of view. The influence in the voltage regulation of the onshore connection busbar is investigated in a 57 bus test power system. The simulation results obtained for each one of the above mentioned transmission system configurations allow the conclusion......As the onshore wind resource is running shorter, wind power promoters are paying attention to the offshore resources. As in most cases there is no load offshore, wind power must be transmitted to the main land. To do so, two options are available: HVAC and HVDC transmission systems. In this paper...... that HVAC solution is limited by the distance to shore and by the wind transmitted power. HVDC options do not show these limitations, but are more expensive and more delicate to deal with, because there is a lack of operational experience, so far....

  6. Simulation of the full and part load energy consumption of HVAC system of building

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, A.E.; Chia, T.H.

    1983-01-01

    A model based on dynamic heat transfers through the building envelope and between the contents inside the building is developed. This model has been incorporated into the Computer Aided Building Airconditioning Requirement and Environmental Temperature Simulation (CABARETS) program. The model takes into account the interaction between the external excitation, building envelope, contents inside the building, air handling systems and the mechanical equipment. An iterative numerical procedure has been implemented to solve the simultaneous heat transfer equations for the various components of the system. The indoor temperature and humidity variations with or without the operation of the HVAC system are established, and the energy requirements for maintaining the controlled environment are computed. The electrical power requirement for operating the HVAC mechanical equipment is estimated by the model, and the values are compared with the observed electricity consumption for the mechanical services.

  7. COMPARATIVE STUDY AMONG HYBRID GROUND SOURCE HEAT PUMP SYSTEM, COMPLETE GROUND SOURCE HEAT PUMP AND CONVENTIONAL HVAC SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Zhu; Yong X. Tao

    2011-11-01

    In this paper, a hotel with hybrid geothermal heat pump system (HyGSHP) in the Pensacola is selected and simulated by the transient simulation software package TRNSYS [1]. To verify the simulation results, the validations are conducted by using the monthly average entering water temperature, monthly facility consumption data, and etc. And three types of HVAC systems are compared based on the same building model and HVAC system capacity. The results are presented to show the advantages and disadvantages of HyGSHP compared with the other two systems in terms of energy consumptions, life cycle cost analysis.

  8. Study of active noise control system for a commercial HVAC unit

    Science.gov (United States)

    Devineni, Naga

    Acoustic noise is a common problem in everyday life. If the appliances that are present in the work and living areas generate noise then it's a serious problem. One such appliance is the Heating, Ventilation and Air-conditioning system (HVAC) in which blower fan and compressor units are housed together. Operation of a HVAC system creates two kinds of noise. One is the noise due to the air flow and the other is the result of the compressor. Both of them exhibit different signal properties and need different strategies to control them. There has been previous efforts in designing noise control systems that can control noise from the HVAC system. These include passive methods which use sound absorption materials to attenuate noise and active methods which cancel noise by generating anti-noise. Passive methods are effective in limiting the high frequency noise, but are inefficient in controlling low frequency noise from the compressor. Compressor noise is one of the strong low frequency components that propagate through the walls, therefore there is need for deploying active signal processing methods that consider the signal properties into consideration to cancel the noise acoustically. The quasi periodic nature of the compressor noise is exploited in noise modeling which aids in implementing an adaptive linear prediction filter in estimating the anti noise [12]. In this thesis, a multi channel architecture has been studied for a specific HVAC system in order to improve noise cancellation by creating larger quiet zone. In addition to the multi-channel architecture, a real time narrow band Active Noise Control (ANC) was employed to cancel noise under practical conditions.

  9. Changes in airborne fungi from the outdoors to indoor air; large HVAC systems in nonproblem buildings in two different climates.

    Science.gov (United States)

    Kemp, P C; Neumeister-Kemp, H G; Esposito, B; Lysek, G; Murray, F

    2003-01-01

    Little is known about the changes in occurrence and distribution of airborne fungi as they are transported in the airstream from the outdoor air through the heating, ventilation, and air conditioning (HVAC) system to the indoor air. To better understand this, airborne fungi were analyzed in the HVAC systems of two large office buildings in different climate zones. Fungal samples were taken in each of the walk-in chambers of the HVAC systems using a six-stage Andersen Sampler with malt extract agar. Results showed that fungal species changed with different locations in the HVAC systems. The outdoor air intake produced the greatest filtration effect for both the counts and species of outdoor air fungi. The colony forming unit (CFU) counts and species diversity was further reduced in the air directly after the filters. The cooling coils also had a substantial filtration effect. However, in room air the CFU counts were double and the mixture of fungal species was different from the air leaving the HVAC system at the supply air outlet in most locations. Diffusion of outdoor air fungi to the indoors did not explain the changes in the mixture of airborne fungi from the outdoor air to the indoor air, and some of the fungi present in the indoor air did not appear to be transported indoors by the HVAC systems.

  10. Commissioning of building HVAC systems for improvement of energy performance; Commissioning of building HVAC systems for improvement of energy performance. Teilnahme IEA-ECBCS Annex 40 (Betreiberkompetenz)

    Energy Technology Data Exchange (ETDEWEB)

    Chuard, J.-M.

    2005-06-15

    This paper takes a look at the tasks performed in Task 40 of the 'Energy Conservation in Buildings and Community Systems ECBCS' programme of the International Energy Agency IEA that is taking a look at the commissioning of building HVAC systems with the aim of improving the energy performance of such systems. Emphasis is put on the Swiss contribution to the task. This well-illustrated paper presents information on the structure of the task, time-lines and a diagram for its implementation structures. Also, the countries participating in Task 40 and their representatives are listed, and various work already published by the annex is noted. The paper places a focus on operator competence and lists points to be taken into account when carrying out work on optimising energy consumption. The various processes involved are noted and discussed. Management guidelines are presented and economical and market aspects are discussed. Finally, projects that will continue the work are noted.

  11. HVAC DDC控制系统的能量管理研究%Study of Energy Management Functions in DDC System for HVAC

    Institute of Scientific and Technical Information of China (English)

    郑萍; 张家川; 潘世永

    2000-01-01

    本文作者论述了HVAC的DDC控制方式及其控制与能量管理相结合的特点,并提出了几种能量管理程序,以及该程序的节能作用.%This paper describes the DDC for HVAC control system and the characteristics of the combination between control and energy management.It gives several energy management programs and analyzes the function of the progrmas in energy saving.

  12. A new pulse modulation adaptive controller (PMAC) applied to HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Salsbury, T.I. [Johnson Controls Inc., Milwaukee (United States)

    2002-12-01

    The paper proposes a new switching control law (pulse modulation adaptive controller, PMAC) that implements pulse-width-pulse-frequency modulation. Pulse durations are determined to maintain the amplitude of variation in the controlled variable at or below a user-defined level. In addition to providing quantifiable control performance, PMAC can reduce component wear by issuing fewer switches than conventional control schemes. The control law is developed around a first-order system characterization but incorporates an adaptive loop, which allows application to a wide range of non-first-order and also time-variant systems. Test results are presented from applying PMAC to both simulated and real HVAC systems. (author)

  13. Power system technical performance issues related to the application of long HVAC cables

    DEFF Research Database (Denmark)

    Wiechowski, on behalf of Cigre WG C4.502, W.; Sluis, L. V. der; Ohno, Teruo

    2011-01-01

    This paper reports the progress of work of Cigre Working Group C4.502 “Power system technical performance issues related to the application of long HVAC cables”. The primary goal of the WG C4.502 is to write a technical brochure that will serve as practical guide for performing studies necessary...... for assessing the technical performance of HV/EHV systems with large share of AC cable lines. This paper besides providing a background for formulation of WG C4.502 and its overall aim, describes the tasks that were accomplished before the interim report was submitted to Study Committee C4 System Technical...

  14. Power System Technical Performance Issues related to the Application of Long HVAC Cables

    DEFF Research Database (Denmark)

    Wiechowski, W.; der Sluis, L.V.; Ohno, Teruo

    2011-01-01

    This paper reports the progress of work of Cigre Working Group C4.502 “Power system technical performance issues related to the application of long HVAC cables”. The primary goal of the WG C4.502 is to write a technical brochure that will serve as practical guide for performing studies necessary...... for assessing the technical performance of HV/EHV systems with large share of AC cable lines. This paper besides providing a background for formulation of WG C4.502 and its overall aim, describes the tasks that were accomplished before the interim report was submitted to Study Committee C4 System Technical...

  15. Evaluation of Heating, Ventilation, and Air conditioning (HVAC System Performance in an Administrative Building in Tehran (Iran

    Directory of Open Access Journals (Sweden)

    H. Mari Oriyad

    2014-09-01

    Full Text Available Introduction: One of the factors influencing on indoor air quality of the buildings is performance of HVAC (heating, ventilation, and air conditioning systems. These systems supply clean and odorless air, with temperature, humidity, and air velocity within comfort ranges for the residents. The aim of this study was to evaluate performance HVAC system in an administrative building in Tehran. .Material and Method: A questionnaire, developed in their research was used to assess the building occupants’ perception about the performance of HVAC system. To evaluate the performance of HVAC systems, air velocities were measured in the diffusers using a thermal anemometer. Moreover, CO2 concentration, air temperature and relative humidity were measured in the whole floors of the building. Air distribution inside the building was evaluated using smoke test. .Results: Most of the studied people complained about the direction of airflow, thermal conditions and cigarette odor. The highest level of carbon dioxide was measured at 930 ppm inside the restaurant. The maximum and minimum air temperatures and relative humidity were measured 28.3-13.8° C and 28.4-23% respectively. Smoke test showed that the air distribution/direction wasn’t suitable in one third of air diffusers. .Conclusion: Improper air distribution / direction was the main problem with the studied HVAC system which could be corrected by adjusting and balancing of the system.

  16. A Subspace Identification Method for Detecting Abnormal Behavior in HVAC Systems

    Directory of Open Access Journals (Sweden)

    Dimitris Sklavounos

    2015-01-01

    Full Text Available A method for the detection of abnormal behavior in HVAC systems is presented. The method combines deterministic subspace identification for each zone independently to create a system model that produces the anticipated zone’s temperature and the sequential test CUSUM algorithm to detect drifts of the rate of change of the difference between the real and the anticipated measurements. Simulation results regarding the detection of infiltration heat losses and the detection of exogenous heat gains such as fire demonstrate the effectiveness of the proposed method.

  17. Classroom HVAC: Improving ventilation and saving energy -- field study plan

    Energy Technology Data Exchange (ETDEWEB)

    Apte, Michael G.; Faulkner, David; Hodgson, Alfred T.; Sullivan, Douglas P.

    2004-10-14

    The primary goals of this research effort are to develop, evaluate, and demonstrate a very practical HVAC system for classrooms that consistently provides classrooms (CRs) with the quantity of ventilation in current minimum standards, while saving energy, and reducing HVAC-related noise levels. This research is motivated by the public benefits of energy efficiency, evidence that many CRs are under-ventilated, and public concerns about indoor environmental quality in CRs. This document provides a summary of the detailed plans developed for the field study that will take place in 2005 to evaluate the energy and IAQ performance of a new classroom HVAC technology. The field study will include measurements of HVAC energy use, ventilation rates, and IEQ conditions in 10 classrooms with the new HVAC technology and in six control classrooms with a standard HVAC system. Energy use and many IEQ parameters will be monitored continuously, while other IEQ measurements will be will be performed seasonally. Continuously monitored data will be remotely accessed via a LonWorks network. Instrument calibration plans that vary with the type of instrumentation used are established. Statistical tests will be employed to compare energy use and IEQ conditions with the new and standard HVAC systems. Strengths of this study plan include the collection of real time data for a full school year, the use of high quality instrumentation, the incorporation of many quality control measures, and the extensive collaborations with industry that limit costs to the sponsors.

  18. Design and Implementation of Energy Efficiency in HVAC Systems Based on Robust PID Control for Industrial Applications

    Directory of Open Access Journals (Sweden)

    Muharrem Imal

    2015-01-01

    Full Text Available Energy efficiency in heating, ventilating, and air-conditioning (HVAC systems is a primary concern in process projects, since the energy consumption has the highest percentage in HVAC for all processes. Without sacrifice of thermal comfort, to reset the suitable operating parameters, such as the humidity and air temperature, would have energy saving with immediate effect. In this paper, the simulation-optimization approach described the effective energy efficiency for HVAC systems which are used in industrial process. Due to the complex relationship of the HVAC system parameters, it is necessary to suggest optimum settings for different operations in response to the dynamic cooling loads and changing weather conditions during a year. Proportional-integral-derivative (PID programming was developed which can effectively handle the discrete, nonlinear and highly constrained optimization problems. Energy efficiency process has been made by controlling of alternative current (AC drivers for ventilation and exhaust fans, according to supplied air flow capacity and differential air pressure between supplied and exhaust air. Supervisory controller software was developed by using programmable controllers and human machine interface (HMI units. The new designed HVAC control system would have a saving potential of about 40% as compared to the existing operational settings, without any extra cost.

  19. Energy fan power consumption comparison of subway station HVAC system

    Institute of Scientific and Technical Information of China (English)

    JIANGYong; ZHUYingxin

    2003-01-01

    Subway thermal environment control system is a mass energy consumed system. The fan operation is the Key of energy saving. Some feasible fan operation modes are proposed and compared in this paper from the view of energy and operation cost saving. It is concluded that VAV is the optimal operation mode for metro system with highest energy saving.

  20. A Comfort-Aware Energy Efficient HVAC System Based on the Subspace Identification Method

    Directory of Open Access Journals (Sweden)

    O. Tsakiridis

    2016-01-01

    Full Text Available A proactive heating method is presented aiming at reducing the energy consumption in a HVAC system while maintaining the thermal comfort of the occupants. The proposed technique fuses time predictions for the zones’ temperatures, based on a deterministic subspace identification method, and zones’ occupancy predictions, based on a mobility model, in a decision scheme that is capable of regulating the balance between the total energy consumed and the total discomfort cost. Simulation results for various occupation-mobility models demonstrate the efficiency of the proposed technique.

  1. Development of DMC controllers for temperature control of a room deploying the displacement ventilation HVAC system

    Directory of Open Access Journals (Sweden)

    Zhicheng Li, Ramesh K. Agarwal, Huijun Gao

    2013-01-01

    Full Text Available In this paper, by developing a new Dynamic Matrix Control (DMC method, we develop a controller for temperature control of a room cooled by a displacement ventilation HVAC system. The fluid flow and heat transfer inside the room are calculated by solving the Reynolds-Averaged Navier-Stokes (RANS equations including the effects of buoyancy in conjunction with a two-equation realizable k - epsilon turbulence model. Thus the physical environment is represented by a nonlinear system of partial differential equations. The system also has a large time delay because of the slowness of the heat exchange. The goal of the paper is to develop a controller that will maintain the temperature at three points near three different walls in a room within the specified upper and lower bounds. In order to solve this temperature control problem at three different points in the room, we develop a special DMC method. The results show that the newly developed DMC controller is an effective controller to maintain temperature within desired bounds at multiple points in the room and also saves energy when compared to other controllers. This DMC method can also be employed to develop controllers for other HVAC systems such as the overhead VAV (Variable Air Volume system and the radiant cooling hydronic system.

  2. Development of DMC controllers for temperature control of a room deploying the displacement ventilation HVAC system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhicheng; Agarwal, Ramesh K. [Department of Mechanical Engineering and Materials Science, Washington University in Saint Louis, MO 63130 (United States); Gao, Huijun [Research Institute of Intelligent Control and Systems, Harbin Institute of Technology, Harbin 150001 (China)

    2013-07-01

    In this paper, by developing a new Dynamic Matrix Control (DMC) method, we develop a controller for temperature control of a room cooled by a displacement ventilation HVAC system. The fluid flow and heat transfer inside the room are calculated by solving the Reynolds-Averaged Navier-Stokes (RANS) equations including the effects of buoyancy in conjunction with a two-equation realizable k - epsilon turbulence model. Thus the physical environment is represented by a nonlinear system of partial differential equations. The system also has a large time delay because of the slowness of the heat exchange. The goal of the paper is to develop a controller that will maintain the temperature at three points near three different walls in a room within the specified upper and lower bounds. In order to solve this temperature control problem at three different points in the room, we develop a special DMC method. The results show that the newly developed DMC controller is an effective controller to maintain temperature within desired bounds at multiple points in the room and also saves energy when compared to other controllers. This DMC method can also be employed to develop controllers for other HVAC systems such as the overhead VAV (Variable Air Volume) system and the radiant cooling hydronic system.

  3. Tools for Evaluating Fault Detection and Diagnostic Methods for HVAC Secondary Systems

    Science.gov (United States)

    Pourarian, Shokouh

    Although modern buildings are using increasingly sophisticated energy management and control systems that have tremendous control and monitoring capabilities, building systems routinely fail to perform as designed. More advanced building control, operation, and automated fault detection and diagnosis (AFDD) technologies are needed to achieve the goal of net-zero energy commercial buildings. Much effort has been devoted to develop such technologies for primary heating ventilating and air conditioning (HVAC) systems, and some secondary systems. However, secondary systems, such as fan coil units and dual duct systems, although widely used in commercial, industrial, and multifamily residential buildings, have received very little attention. This research study aims at developing tools that could provide simulation capabilities to develop and evaluate advanced control, operation, and AFDD technologies for these less studied secondary systems. In this study, HVACSIM+ is selected as the simulation environment. Besides developing dynamic models for the above-mentioned secondary systems, two other issues related to the HVACSIM+ environment are also investigated. One issue is the nonlinear equation solver used in HVACSIM+ (Powell's Hybrid method in subroutine SNSQ). It has been found from several previous research projects (ASRHAE RP 825 and 1312) that SNSQ is especially unstable at the beginning of a simulation and sometimes unable to converge to a solution. Another issue is related to the zone model in the HVACSIM+ library of components. Dynamic simulation of secondary HVAC systems unavoidably requires an interacting zone model which is systematically and dynamically interacting with building surrounding. Therefore, the accuracy and reliability of the building zone model affects operational data generated by the developed dynamic tool to predict HVAC secondary systems function. The available model does not simulate the impact of direct solar radiation that enters a zone

  4. Modernisation of space HVAC systems with high energy consumption; Sanierung von RLT-Anlagen mit hohen Energieverbraeuchen

    Energy Technology Data Exchange (ETDEWEB)

    Willan, U. [ROM (Rud. Otto Meyer) - Technik fuer Mensch und Umwelt, Hamburg (Germany). Zentralbereich Ingenieurtechnik

    1997-12-31

    For office buildings and similarly used buildings, concepts are developed for the modernization of space hvac systems. The state of work in the following sectors is discussed: optimum comparison processes for space HVAC systems, measurements to assess the performance of alternative dehumidification and cooling systems, heat-physiological space model. (MSK) [Deutsch] Fuer Buerobauten und Gebaeude aehnlicher Nutzung werden Sanierungskonzepte fuer RLT-Anlagen erarbeitet. Im Folgenden wird der Stand der Arbeiten in den Bereichen: optimale Vergleichsprozesse fuer RLT-Anlagen, messtechnische Beurteilung alternativer Entfeuchtungs- und Kuehlsysteme sowie ein waermetechnisches Raummodell erlaeutert.

  5. COMPREHENSIVE DIAGNOSTIC AND IMPROVEMENT TOOLS FOR HVAC-SYSTEM INSTALLATIONS IN LIGHT COMMERCIAL BUILDINGS

    Energy Technology Data Exchange (ETDEWEB)

    Abram Conant; Mark Modera; Joe Pira; John Proctor; Mike Gebbie

    2004-10-31

    Proctor Engineering Group, Ltd. (PEG) and Carrier-Aeroseal LLP performed an investigation of opportunities for improving air conditioning and heating system performance in existing light commercial buildings. Comprehensive diagnostic and improvement tools were created to address equipment performance parameters (including airflow, refrigerant charge, and economizer operation), duct-system performance (including duct leakage, zonal flows and thermal-energy delivery), and combustion appliance safety within these buildings. This investigation, sponsored by the National Energy Technology Laboratory, a division of the U.S. Department of Energy, involved collaboration between PEG and Aeroseal in order to refine three technologies previously developed for the residential market: (1) an aerosol-based duct sealing technology that allows the ducts to be sealed remotely (i.e., without removing the ceiling tiles), (2) a computer-driven diagnostic and improvement-tracking tool for residential duct installations, and (3) an integrated diagnosis verification and customer satisfaction system utilizing a combined computer/human expert system for HVAC performance. Prior to this work the aerosol-sealing technology was virtually untested in the light commercial sector--mostly because the savings potential and practicality of this or any other type of duct sealing had not been documented. Based upon the field experiences of PEG and Aeroseal, the overall product was tailored to suit the skill sets of typical HVAC-contractor personnel.

  6. 10 CFR 434.517 - HVAC systems and equipment.

    Science.gov (United States)

    2010-01-01

    ... zone Packaged terminal air conditioner with space heater or heat pump, one heating/cooling unit per... conditioner w/space heater (Note 8) Hot water (Note 8, 12) Hot water (Note 12) or electric resistance (Note B... and Reference Buildings 1,2 Building/space occupancy System No. (Table 517.4.1) Remarks (Table 517.4.1...

  7. Simulation Study of IMC and Fuzzy Controller for HVAC System

    Directory of Open Access Journals (Sweden)

    Umamaheshwari

    2009-06-01

    Full Text Available This paper presents how the fuzzy logic controller is used to solve the control problems of complex and non linear process and show that it is more robust and their performance are less sensitive to parametric variations than conventional controllers. These systems will yield a linear response when compared to ordinary controllers. The main advantage of Fuzzy control over conventional controllers is regulation can be done without over shoot.

  8. Modular VSC converter based HVDC power transmission from offshore wind power plant: Compared to the conventional HVAC system

    DEFF Research Database (Denmark)

    Sharma, Ranjan; Rasmussen, Tonny Wederberg; Jensen, Kim Høj;

    2010-01-01

    power transmission options with HVDC systems are under consideration. In this paper, a comparison between a conventional HVAC transmission system and a HVDC system equipped with modular voltage source converters is provided. The comparison is based on the total energy transmission capability...

  9. Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes - Business Case Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D [ORNL

    2007-05-01

    The long range strategic goal of the Department of Energy's Building Technologies (DOE/BT) Program is to create, by 2020, technologies and design approaches that enable the construction of net-zero energy homes at low incremental cost (DOE/BT 2005). A net zero energy home (NZEH) is a residential building with greatly reduced needs for energy through efficiency gains, with the balance of energy needs supplied by renewable technologies. While initially focused on new construction, these technologies and design approaches are intended to have application to buildings constructed before 2020 as well resulting in substantial reduction in energy use for all building types and ages. DOE/BT's Emerging Technologies (ET) team is working to support this strategic goal by identifying and developing advanced heating, ventilating, air-conditioning, and water heating (HVAC/WH) technology options applicable to NZEHs. Although the energy efficiency of heating, ventilating, and air-conditioning (HVAC) equipment has increased substantially in recent years, new approaches are needed to continue this trend. Dramatic efficiency improvements are necessary to enable progress toward the NZEH goals, and will require a radical rethinking of opportunities to improve system performance. The large reductions in HVAC energy consumption necessary to support the NZEH goals require a systems-oriented analysis approach that characterizes each element of energy consumption, identifies alternatives, and determines the most cost-effective combination of options. In particular, HVAC equipment must be developed that addresses the range of special needs of NZEH applications in the areas of reduced HVAC and water heating energy use, humidity control, ventilation, uniform comfort, and ease of zoning. In FY05 ORNL conducted an initial Stage 1 (Applied Research) scoping assessment of HVAC/WH systems options for future NZEHs to help DOE/BT identify and prioritize alternative approaches for further

  10. Preliminary CFD Analysis for HVAC System Design of a Containment Building

    Energy Technology Data Exchange (ETDEWEB)

    Son, Sung Man; Choi, Choengryul [ELSOLTEC, Yongin (Korea, Republic of); Choo, Jae Ho; Hong, Moonpyo; Kim, Hyungseok [KEPCO Engineering and Construction, Gimcheon (Korea, Republic of)

    2016-10-15

    HVAC (Heating, Ventilation, Air Conditioning) system has been mainly designed based on overall heat balance and averaging concepts, which is simple and useful for designing overall system. However, such a method has the disadvantage that cannot predict the local flow and temperature distributions in a containment building. In this study, a CFD (Computational Fluid Dynamics) preliminary analysis is carried out to obtain detailed flow and temperature distributions in a containment building and to ensure that such information can be obtained via CFD analysis. This approach can be useful for hydrogen analysis in an accident related to hydrogen released into a containment building. In this study, CFD preliminary analysis has been performed to obtain the detailed information of the reactor containment building by using the CFD analysis techniques and to ensure that such information can be obtained via CFD analysis. We confirmed that CFD analysis can offer enough detailed information about flow patterns and temperature field and that CFD technique is a useful tool for HVAC design of nuclear power plants.

  11. Energy efficient model based algorithm for control of building HVAC systems.

    Science.gov (United States)

    Kirubakaran, V; Sahu, Chinmay; Radhakrishnan, T K; Sivakumaran, N

    2015-11-01

    Energy efficient designs are receiving increasing attention in various fields of engineering. Heating ventilation and air conditioning (HVAC) control system designs involve improved energy usage with an acceptable relaxation in thermal comfort. In this paper, real time data from a building HVAC system provided by BuildingLAB is considered. A resistor-capacitor (RC) framework for representing thermal dynamics of the building is estimated using particle swarm optimization (PSO) algorithm. With objective costs as thermal comfort (deviation of room temperature from required temperature) and energy measure (Ecm) explicit MPC design for this building model is executed based on its state space representation of the supply water temperature (input)/room temperature (output) dynamics. The controllers are subjected to servo tracking and external disturbance (ambient temperature) is provided from the real time data during closed loop control. The control strategies are ported on a PIC32mx series microcontroller platform. The building model is implemented in MATLAB and hardware in loop (HIL) testing of the strategies is executed over a USB port. Results indicate that compared to traditional proportional integral (PI) controllers, the explicit MPC's improve both energy efficiency and thermal comfort significantly.

  12. Learning Based Bidding Strategy for HVAC Systems in Double Auction Retail Energy Markets

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yannan; Somani, Abhishek; Carroll, Thomas E.

    2015-07-01

    In this paper, a bidding strategy is proposed using reinforcement learning for HVAC systems in a double auction market. The bidding strategy does not require a specific model-based representation of behavior, i.e., a functional form to translate indoor house temperatures into bid prices. The results from reinforcement learning based approach are compared with the HVAC bidding approach used in the AEP gridSMART® smart grid demonstration project and it is shown that the model-free (learning based) approach tracks well the results from the model-based behavior. Successful use of model-free approaches to represent device-level economic behavior may help develop similar approaches to represent behavior of more complex devices or groups of diverse devices, such as in a building. Distributed control requires an understanding of decision making processes of intelligent agents so that appropriate mechanisms may be developed to control and coordinate their responses, and model-free approaches to represent behavior will be extremely useful in that quest.

  13. Energy Savings Potential of Flexible and Adaptive HVAC Distribution Systems for Office Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Loftness, Vivian; Brahme, Rohini; Mondazzi, Michelle; Vineyard, Edward; MacDonald, Michael

    2002-06-01

    It has been understood by architects and engineers that office buildings with easily re-configurable space and flexible mechanical and electrical systems are able to provide comfort that increases worker productivity while using less energy. Raised floors are an example of how fresh air, thermal conditioning, lighting needs, and network access can be delivered in a flexible manner that is not ''embedded'' within the structure. What are not yet documented is how well these systems perform and how much energy they can save. This area is being investigated in phased projects of the 21st Century Research Program of the Air-conditioning and Refrigeration Technology Institute. For the initial project, research teams at the Center for Building Performance and Diagnostics, Pittsburgh, Pennsylvania, and Oak Ridge National Laboratory, Oak Ridge, Tennessee, documented the diversity, performance, and incidence of flexible and adaptive HVAC systems. Information was gathered worldwide from journal and conference articles, case studies, manufactured products and assemblies, and interviews with design professionals. Their report thoroughly describes the variety of system types along with the various design alternatives observed for plenums, diffusers, individual control, and system integration. Many of the systems are illustrated in the report and the authors provide quantitative and qualitative comparisons. Among conclusions regarding key design issues, and barriers to widespread adoption, the authors state that flexible and adaptive HVAC systems, such as underfloor air, perform as well if not better than ceiling-based systems. Leading engineers have become active proponents after their first experience, which is resulting in these flexible and adaptive HVAC systems approaching 10 percent of the new construction market. To encourage adoption of this technology that improves thermal comfort and indoor air quality, follow-on work is required to further document

  14. Building HVAC control knowledge data schema – Towards a unified representation of control system knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan; Treado, Stephen J.; Messner, John I.

    2016-12-01

    Building control systems for Heating, Ventilation, and Air Conditioning (HVAC) play a key role in realizing the functionality and operation of building systems and components. Building Control Knowledge (BCK) is the logic and algorithms embedded throughout building control system. There are different methods to represent the BCK. These methods differ in the selection of BCK representing elements and the format of those elements. There is a lack of standard data schema, for storing, retrieving, and reusing structured BCK. In this study, a modular data schema is created for BCK representation. The data schema contains eleven representing elements, i.e., control module name, operation mode, system schematic, control flow diagram, data point, alarm, parameter, control sequence, function, and programming code. Each element is defined with specific attributes. This data schema is evaluated through a case study demonstration. The demonstration shows a new way to represent the BCK with standard formats.

  15. The integrated engineering system for the HVAC branch. Annex; Das integrierte Ingenieursystem fuer die Haustechnikbranche; Anhang

    Energy Technology Data Exchange (ETDEWEB)

    Allenspach, J.; Duppenthaler, A.; Helbling, R.; Kohler, T.; Mantel, R.; Meineke, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1994-01-01

    In 1987, the intention of the former Swiss Federal Institute for Reactor Research was to initiate a transfer of know-how into practice by launching this project. The increasing need for software engineering tools by heating, ventilation and air conditioning (HVAC) companies demanded a new tool; to realise it, a joint venture project with private industry should concentrate the individual capabilities of each partner toward this goal. The present report describes the concept of the integrated engineering system, its user interface, the models, graphics, tools, multiuser operation and the system boundary. Results of field tests are presented together with information of the availability of the system. The annex contains the agreement for the usage of the public-domain-version of the system, experience reports of pilot clients and the end user`s and developer`s documentation. (author) figs., tabs., refs.

  16. A new HVAC system based on cogeneration by an i.c. engine

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M. [Istituto di Ingeneria Gestionale, Universita di Padova (Italy); Longo, G.A.; Romagnoni, P.C. [Istituto di Fisica Tecnica, Universita di Padova (Italy)

    1996-07-01

    A new HVAC system is proposed and studied. The plant is equipped with a reciprocating i.c. gas engine which produces electric energy with heat recovery from the jacket water heat and the exhaust. The electric energy serves the lighting and emf for the building and individual room reversible air-water heat pumps that mainly satisfy sensible cooling and a fraction of the winter heating load. An open-cycle absorption system, which treats the primary air, meets the summer latent load and year round ventilation requirements. In winter, the system operates as an open-cycle heat pump. The regeneration of the sorbent is obtained by the i.c. engine heat recovery. The proposed system is analysed by comparing its performance with a traditional plant, both in summer and winter mode. (Author)

  17. Strategy Guideline: HVAC Equipment Sizing

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, A.

    2012-02-01

    The heating, ventilation, and air conditioning (HVAC) system is arguably the most complex system installed in a house and is a substantial component of the total house energy use. A right-sized HVAC system will provide the desired occupant comfort and will run efficiently. This Strategy Guideline discusses the information needed to initially select the equipment for a properly designed HVAC system. Right-sizing of an HVAC system involves the selection of equipment and the design of the air distribution system to meet the accurate predicted heating and cooling loads of the house. Right-sizing the HVAC system begins with an accurate understanding of the heating and cooling loads on a space; however, a full HVAC design involves more than just the load estimate calculation - the load calculation is the first step of the iterative HVAC design procedure. This guide describes the equipment selection of a split system air conditioner and furnace for an example house in Chicago, IL as well as a heat pump system for an example house in Orlando, Florida. The required heating and cooling load information for the two example houses was developed in the Department of Energy Building America Strategy Guideline: Accurate Heating and Cooling Load Calculations.

  18. Experimental investigation of cooling performance of a novel HVAC system combining natural ventilation with diffuse ceiling inlet and TABS

    DEFF Research Database (Denmark)

    Yu, Tao; Heiselberg, Per Kvols; Lei, Bo;

    2015-01-01

    Highlights •An experimental investigation of cooling performance of a combined HVAC system is carried out. •Cooling performance of TABS with and without the influence of diffuse ceiling is analyzed. •Radiant and convective heat transfer coefficients of TABS cooling are studied. •Cooling components...

  19. Value impact analysis of Generic Issue 143, Availability of Heating, Ventilation, Air Conditioning (HVAC) and Chilled Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Daling, P.M.; Marler, J.E.; Vo, T.V.; Phan, H.; Friley, J.R. [Pacific Northwest Lab., Richland, WA (United States)

    1993-11-01

    This study evaluates the values (benefits) and impacts (costs) associated with potential resolutions to Generic Issue 143, ``Availability of HVAC and Chilled Water Systems.`` The study identifies vulnerabilities related to failures of HVAC, chilled water, and room cooling systems; develops estimates of room heatup rates and safety-related equipment vulnerabilities following losses of HVAC/room cooler systems; develops estimates of the core damage frequencies and public risks associated with failures of these systems; develops three proposed resolution strategies to this generic issue; and performs a value/impact analysis of the proposed resolutions. Existing probabilistic risk assessments for four representative plants, including one plant from each vendor, form the basis for the core damage frequency and public risk calculations. Both internal and external events were considered. It was concluded that all three proposed resolution strategies exceed the $1,000/person-rem cost-effectiveness ratio. Additional evaluations were performed to develop ``generic`` insights on potential design-related and configuration-related vulnerabilities and potential high-frequency ({approximately}1E-04/RY) accident sequences that involve failures of HVAC/room cooling functions. It was concluded that, although high-frequency accident sequences may exist at some plants, these high-frequency sequences are plant-specific in nature or have been resolved through hardware and/or operational changes. The plant-specific Individual Plant Examinations are an effective vehicle for identification and resolution of these plant-specific anomalies and hardware configurations.

  20. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    Directory of Open Access Journals (Sweden)

    Mohamad Ramadan

    2015-09-01

    Full Text Available In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particularly uses the waste energy of the condenser hot air to heat/preheat domestic water. The heat exchanger considered in the recovery system is concentric tube heat exchanger. A thermal modeling of the complete system as well as a corresponding iterative code are developed and presented. Calculations with the code are performed and give pertinent magnitude orders of energy saving and management in HVAC applications. A parametric analysis based on several water and air flow rates is carried out. It was shown that water can be heated from 25 to 70 °C depending on the mass flow rates and cooling loads of the HVAC system. The most efficient configurations are obtained by lowering the air flow rate of the condenser fan.

  1. A Study on the Application of UV Sterilization Method in HVAC System

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S. W.; Park, J. S.; Seo, I. W.; Lim, K. R.; An, W. S.; Oh, S. H.; Lee, K. W.; Kim, J. G.; Kwon, S. J

    2005-04-15

    The objective of this report is to study on the application of UV sterilization method on HVAC system in building. One type of commercial UV lamp was utilized during this research. It was 1,050 mm length, 24.5 mm diameter, 65 w lamp output, single ended lamp intended for insertion into al frame from inside. Twenty six lamps were mounted and operated in cross flow. They were allowed to operate for at least 30 minutes prior to beginning each test. The test rig was operated at 2.5 m/s and 20 .deg. C, and the relatively humidity 21.6 %RH. The effect of UV sterilization are investigated that as the general virus about 94 %, the mold microbe about 64 % and the bacillus about 86 %, respectively. Following this report will be used important data for the design and manufacture of the UV.

  2. Simulative Study into the Development of a Hybrid HVDC System Through a Comparative Research with HVAC: a Futuristic Approach

    Directory of Open Access Journals (Sweden)

    R. S. Narayan

    2017-06-01

    Full Text Available High Voltage Direct Current Transmission (HVDC is considered a better solution for bulk long distance transmissions. The increased use of HVDC is a result of its advantages over the HVAC systems and especially of its fault stability nature. A better solution is proposed by using a Voltage Source Controlled–HVDC as one of the infeed for the Multi-Infeed HVDC (MIDC or MI-HVDC systems. The main advantage with the VSC converter is its flexible power control which enhances the stability of the MIDC systems. In this paper, the behavior of an HVDC system is compared with that of an HVAC during faults. A Hybrid HVDC system that includes a LCC as a rectifier unit and a VSC converter as the inverter is being proposed. It is considered suitable for MIDC systems and particularly for supplying a weak AC system. The performance of the system during steady state and transient conditions for all the proposed topologies including HVDC, HVAC and Hybrid HVDC are studied in MATLAB/SIMULINK. All of the proposed control strategies are evaluated via a series of simulation case studies.

  3. Energy Savings From System Efficiency Improvements in Iowa's HVAC SAVE Program

    Energy Technology Data Exchange (ETDEWEB)

    Yee, S. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States); Baker, J. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States); Brand, L. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States); Wells, J. [Partnership for Advanced Residential Retrofit, Chicago, IL (United States)

    2013-08-01

    The objective of this project is to explore the energy savings potential of maximizing furnace and distribution system performance by adjusting operating, installation, and distribution conditions. The goal of the Iowa HVAC System Adjusted and Verified Efficiency (SAVE) program is to train contractors to measure installed system efficiency as a diagnostic tool to ensure that the homeowner achieves the energy reduction target for the home rather than simply performing a tune-up on the furnace or having a replacement furnace added to a leaky system. The PARR research team first examined baseline energy usage from a sample of 48 existing homes, before any repairs or adjustments were made, to calculate an average energy savings potential and to determine which system deficiencies were prevalent. The results of the baseline study of these homes found that, on average, about 10% of the space heating energy available from the furnace was not reaching the conditioned space. In the second part of the project, the team examined a sample of 10 homes that had completed the initial evaluation for more in-depth study. For these homes, the diagnostic data shows that it is possible to deliver up to 23% more energy from the furnace to the conditioned space by doing system tune ups with or without upgrading the furnace. Replacing the furnace provides additional energy reduction. The results support the author's belief that residential heating and cooling equipment should be tested and improved as a system rather than a collection of individual components.

  4. 石油钻机司钻房 HVAC 系统设计与分析%System Design and Analysis of HVAC System Design and Analysis of Driller Roon in Oil Rig

    Institute of Scientific and Technical Information of China (English)

    樊春明; 孔美虹; 韩俊; 张文英; 王长怀; 李永国

    2014-01-01

    介绍了石油钻机司钻房HVAC系统组成、工作原理、关键参数确定和主要部件设计及选型。%It introduces the composition, working theory, determination of key parameters, de-sign and selection of the main components of HVAC system of driller roon in oil rig .

  5. Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D [ORNL

    2006-11-01

    The long range strategic goal of the Department of Energy's Building Technologies (DOE/BT) Program is to create, by 2020, technologies and design approaches that enable the construction of net-zero energy homes at low incremental cost (DOE/BT 2005). A net zero energy home (NZEH) is a residential building with greatly reduced needs for energy through efficiency gains, with the balance of energy needs supplied by renewable technologies. While initially focused on new construction, these technologies and design approaches are intended to have application to buildings constructed before 2020 as well resulting in substantial reduction in energy use for all building types and ages. DOE/BT's Emerging Technologies (ET) team is working to support this strategic goal by identifying and developing advanced heating, ventilating, air-conditioning, and water heating (HVAC/WH) technology options applicable to NZEHs. Although the energy efficiency of heating, ventilating, and air-conditioning (HVAC) equipment has increased substantially in recent years, new approaches are needed to continue this trend. Dramatic efficiency improvements are necessary to enable progress toward the NZEH goals, and will require a radical rethinking of opportunities to improve system performance. The large reductions in HVAC energy consumption necessary to support the NZEH goals require a systems-oriented analysis approach that characterizes each element of energy consumption, identifies alternatives, and determines the most cost-effective combination of options. In particular, HVAC equipment must be developed that addresses the range of special needs of NZEH applications in the areas of reduced HVAC and water heating energy use, humidity control, ventilation, uniform comfort, and ease of zoning. In FY05 ORNL conducted an initial Stage 1 (Applied Research) scoping assessment of HVAC/WH systems options for future NZEHs to help DOE/BT identify and prioritize alternative approaches for further

  6. An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Trcka, Marija; Wetter, Michael; Hensen, Jan L.M.

    2010-07-01

    Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC) systems can help reducing energy consumption and increasing level of occupant comfort. However, no singe building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to accommodate the ever-increasing complexity and rapid innovations in building and system technologies. One way to alleviate this problem is to use co-simulation. The co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This paper elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in a co-simulation prototype. The prototype is verified and validated against the results obtained from the traditional simulation approach. It is further used in a case study for the proof-of-concept, to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling frequency. The paper concludes by defining requirements and recommendations for generic cosimulation implementations.

  7. Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

    Science.gov (United States)

    Möritz, M; Peters, H; Nipko, B; Rüden, H

    2001-07-01

    The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry ( 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

  8. Thermal room modelling adapted to the test of HVAC control systems; Modele de zone adapte aux essais de regulateurs de systemes de chauffage et de climatisation

    Energy Technology Data Exchange (ETDEWEB)

    Riederer, P.

    2002-01-15

    Room models, currently used for controller tests, assume the room air to be perfectly mixed. A new room model is developed, assuming non-homogeneous room conditions and distinguishing between different sensor positions. From measurement in real test rooms and detailed CFD simulations, a list of convective phenomena is obtained that has to be considered in the development of a model for a room equipped with different HVAC systems. The zonal modelling approach that divides the room air into several sub-volumes is chosen, since it is able to represent the important convective phenomena imposed on the HVAC system. The convective room model is divided into two parts: a zonal model, representing the air at the occupant zone and a second model, providing the conditions at typical sensor positions. Using this approach, the comfort conditions at the occupant zone can be evaluated as well as the impact of different sensor positions. The model is validated for a test room equipped with different HVAC systems. Sensitivity analysis is carried out on the main parameters of the model. Performance assessment and energy consumption are then compared for different sensor positions in a room equipped with different HVAC systems. The results are also compared with those obtained when a well-mixed model is used. A main conclusion of these tests is, that the differences obtained, when changing the position of the controller's sensor, is a function of the HVAC system and controller type. The differences are generally small in terms of thermal comfort but significant in terms of overall energy consumption. For different HVAC systems the cases are listed, in which the use of a simplified model is not recommended. (author)

  9. Computational Fluid Dynamic Modeling of Horizontal Air-Ground Heat Exchangers (HAGHE for HVAC Systems

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2014-12-01

    Full Text Available In order to satisfy the requirements of Directive 2010/31/EU for Zero Energy Buildings (ZEB, innovative solutions were investigated for building HVAC systems. Horizontal air-ground heat exchangers (HAGHE offer a significant contribution in reducing energy consumption for ventilation, using the thermal energy stored underground, in order to pre-heat or pre-cool the ventilation air, in winter and summer, respectively. This is particularly interesting in applications for industrial, commercial and education buildings where keeping the indoor air quality under control is extremely important. Experimental measurements show that, throughout the year, the outside air temperature fluctuations are mitigated at sufficient ground depth (about 3 m because of the high thermal inertia of the soil, the ground temperature is relatively constant and instead higher than that of the outside air in winter and lower in summer. The study aims to numerically investigate the behavior of HAGHE by varying the air flow rate and soil conductivity in unsteady conditions by using annual weather data of South-East Italy. The analysis shows that, in warm climates, the HAGHE brings a real advantage for only a few hours daily in winter, while it shows significant benefits in the summer for the cooling of ventilation air up to several temperature degrees, already by a short pipe.

  10. Switched Control Strategies of Aggregated Commercial HVAC Systems for Demand Response in Smart Grids

    Directory of Open Access Journals (Sweden)

    Kai Ma

    2017-07-01

    Full Text Available This work proposes three switched control strategies for aggregated heating, ventilation, and air conditioning (HVAC systems in commercial buildings to track the automatic generation control (AGC signal in smart grid. The existing control strategies include the direct load control strategy and the setpoint regulation strategy. The direct load control strategy cannot track the AGC signal when the state of charge (SOC of the aggregated thermostatically controlled loads (TCLs exceeds their regulation capacity, while the setpoint regulation strategy provides flexible regulation capacity, but causes larger tracking errors. To improve the tracking performance, we took the advantages of the two control modes and developed three switched control strategies. The control strategies switch between the direct load control mode and the setpoint regulation mode according to different switching indices. Specifically, we design a discrete-time controller and optimize the controller parameter for the setpoint regulation strategy using the Fibonacci optimization algorithm, enabling us to propose two switched control strategies across multiple time steps. Furthermore, we extend the switched control strategies by introducing a two-stage regulation in a single time step. Simulation results demonstrate that the proposed switched control strategies can reduce the tracking errors for frequency regulation.

  11. Breathing Easier: HVAC Specifications for Schools.

    Science.gov (United States)

    Trent, C. Curtis; Trent, Warren C.

    1996-01-01

    A major source of indoor air contamination in schools originates within the heating, ventilating, and air-conditioning systems (HVAC), with draw-through systems being the worst offenders. Lists provisions for designing an HVAC system and a set of criteria to adhere to when planning new construction or renovations. (nine references) (MLF)

  12. Breathing Easier: HVAC Specifications for Schools.

    Science.gov (United States)

    Trent, C. Curtis; Trent, Warren C.

    1996-01-01

    A major source of indoor air contamination in schools originates within the heating, ventilating, and air-conditioning systems (HVAC), with draw-through systems being the worst offenders. Lists provisions for designing an HVAC system and a set of criteria to adhere to when planning new construction or renovations. (nine references) (MLF)

  13. Investigation of the potential antimicrobial efficacy of sealants used in HVAC systems.

    Science.gov (United States)

    Foarde, K K; VanOsdell, D W; Menetrez, M Y

    2001-08-01

    Recent experiments confirm field experience that duct cleaning alone may not provide adequate protection from regrowth of fungal contamination on fiberglass duct liner (FGDL). Current recommendations for remediation of fungally contaminated fiberglass duct materials specify complete removal of the materials. But removal of contaminated materials can be extremely expensive. Therefore, a common practice in the duct-cleaning industry is the postcleaning use of antimicrobial surface coatings with the implication that they may contain or limit regrowth. Little information is available on the efficacy of these treatments. This paper describes a study to evaluate whether three commercially available antimicrobial coatings, placed on a cleaned surface that 1 year previously had been actively growing microorganisms, would be able to prevent regrowth. The three coatings contained different active antimicrobial compounds. All three of the coatings were designed for use on heating, ventilation, and air conditioning (HVAC) system components or interior surfaces of lined and unlined duct systems. Coating I was a polyacrylate copolymer containing zinc oxide and borates. Coating II was an acrylic coating containing decabromodiphenyl oxide and antimony trioxide. Coating III was an acrylic primer containing a phosphated quaternary amine complex. The study included field and laboratory assessments. The three treatments were evaluated in an uncontrolled field setting in an actual duct system. The laboratory study broadened the field study to include a range of humidities under controlled conditions. Both static and dynamic chamber laboratory experiments were performed. The results showed that two of the three antimicrobial coatings limited the regrowth of fungal contamination, at least in the short term (the 3-month time span of the study); the third did not. Before use in the field, testing of the efficacy of antimicrobial coatings under realistic use conditions is recommended

  14. Maintaining consistency in distributed systems

    Science.gov (United States)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  15. HVAC controls: Operation and maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Gupton, G.W. Jr.

    1987-01-01

    The introductory chapters review HVAC system processes and equipment, control system types and equipment, and equipment-to-control interactions. The succeeding chapters cover specific control systems functions, including electrical interlock and motor starting, electrical and electronic control system diagrams, pneumatic control system diagrams, air supply to pneumatic control systems, and control system maintenance.

  16. The role of ventilation and HVAC systems for human health in nonindustrial indoor environments. A supplementary review by EUROVEN group

    DEFF Research Database (Denmark)

    Wargocki, Pawel; Sundell, Jan; Bischof, W.;

    2002-01-01

    with increased productivity, and that air-conditioning systems may increase the risk of sick building syndrome (SBS) symptoms. Taking these findings into account, the group has elaborated 35 hypotheses on the role of ventilation ahd HVAC systems in nonindustrial indoor environments with regard to human health......A continuation of the earlier work of the multidisciplinary group of European scientists, EUROVEN, is presented. The group has previously concluded that increased ventilation rates in indoor nonindustrial environments are strongly associated with improved comfort and health and may be associated...... of ventilation and air-conditioning systems, as well as their intermittent operation, may be potential reasons for health problems of people staying indoors....

  17. Co-simulation for performance prediction of integrated building and HVAC systems - An analysis of solution characteristics using a two-body system

    Energy Technology Data Exchange (ETDEWEB)

    Trcka, Marija; L.M. Hensena, Jan; Wetter, Michael

    2010-06-21

    Integrated performance simulation of buildings and heating, ventilation and airconditioning (HVAC) systems can help reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers suffcient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation to integrate different BPS tools. Co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This article analyzes how co-simulation influences consistency, stability and accuracy of the numerical approximation to the solution. Consistency and zero-stability are studied for a general class of the problem, while a detailed consistency and absolute stability analysis is given for a simple two-body problem. Since the accuracy of the numerical approximation to the solution is reduced in co-simulation, the article concludes by discussing ways for how to improve accuracy.

  18. Fault ride-through and grid support of permanent magnet synchronous generator-based wind farms with HVAC and VSC-HVDC transmission systems

    DEFF Research Database (Denmark)

    Liu, Hongzhi; Chen, Zhe

    2012-01-01

    This paper describes fault ride-through and grid support of offshore wind farms based on permanent magnet synchronous generator (PMSG) wind turbines connected to the onshore AC network through two alternative transmission systems: high voltage AC (HVAC) or high voltage DC (HVDC) based on voltage...... source converters (VSC). The proposed configurations of the PMSG-based offshore wind farm and VSC-based HVDC are given as well as their control strategies under both steady state and fault state. The PMSG-based offshore wind farm is integrated into a test power transmission system via either HVAC or VSC-HVDC...

  19. Evaluating the potential efficacy of three antifungal sealants of duct liner and galvanized steel as used in HVAC systems.

    Science.gov (United States)

    Foarde, Karin K; Menetrez, M Y

    2002-07-01

    Current recommendations for remediation of fiberglass duct materials contaminated with fungi specify complete removal, which can be extremely expensive, but in-place duct cleaning may not provide adequate protection from regrowth of fungal contamination. Therefore, a common practice in the duct-cleaning industry is the postcleaning use of antifungal surface coatings with the implication that they may contain or limit regrowth. However, even the proper use of these products has generally been discouraged because little research has been conducted on the effectiveness of most products as used in heating, ventilating, and air-conditioning (HVAC) systems. Three different coatings were evaluated on fiberglass duct liner (FGDL). Two of the three coatings were able to limit growth in the 3-month study; the third did not. One of the coatings that was able to limit growth was further evaluated in a comparison of FGDL or galvanized steel (GS) under conditions that mimicked their use in HVAC systems. The results showed that both moderately soiled and heavily soiled uncoated FGDL and GS duct material can support fungal growth, but that GS duct material was more readily cleaned. The use of an antifungal coating helped limit, but did not fully contain, regrowth on FGDL. No regrowth was detected on the coated GS.

  20. Fumigation of a laboratory-scale HVAC system with hydrogen peroxide for decontamination following a biological contamination incident.

    Science.gov (United States)

    Meyer, K M; Calfee, M W; Wood, J P; Mickelsen, L; Attwood, B; Clayton, M; Touati, A; Delafield, R

    2014-03-01

    To evaluate hydrogen peroxide vapour (H2 O2 ) for its ability to inactivate Bacillus spores within a laboratory-scale heating, ventilation and air-conditioning (HVAC) duct system. Experiments were conducted in a closed-loop duct system, constructed of either internally lined or unlined galvanized metal. Bacterial spores were aerosol-deposited onto 18-mm-diameter test material coupons and strategically placed at several locations within the duct environment. Various concentrations of H2 O2 and exposure times were evaluated to determine the sporicidal efficacy and minimum exposure needed for decontamination. For the unlined duct, high variability was observed in the recovery of spores between sample locations, likely due to complex, unpredictable flow patterns within the ducts. In comparison, the lined duct exhibited a significant desorption of the H2 O2 following the fumigant dwell period and thus resulted in complete decontamination at all sampling locations. These findings suggest that decontamination of Bacillus spore-contaminated unlined HVAC ducts by hydrogen peroxide fumigation may require more stringent conditions (higher concentrations, longer dwell duration) than internally insulated ductwork. These data may help emergency responders when developing remediation plans during building decontamination. © 2013 The Society for Applied Microbiology This article has been contributed to by US Government employees and their work is in the public domain in the USA.

  1. Comparison of Energy Performance of Different HVAC Systems for a Typical Office Room and a Typical Classroom

    DEFF Research Database (Denmark)

    Yu, Tao; Heiselberg, Per; Pomianowski, Michal Zbigniew

    This report is part of the work performed under the project “Natural cooling and Ventilation through Diffuse Ceiling Supply and Thermally Activated Building Constructions”. In this project, a new system solution combining natural ventilation with diffuse ceiling inlet and thermally activated...... the energy consumption for buildings with cooling demand in cold seasons. In this way, the building system can operate at a very low energy use all the year round. The main purpose of this task is to investigate the energy performance of different HVAC systems used in the office room and the classroom......, and find the potential of energy saving for the proposed new system solution. In this report, a typical room is selected according to the previous study, but the occupation is different for the purpose of the office and the classroom. Energy performance of these two types of room under different internal...

  2. Evaluation of commercially available techniques and development of simplified methods for measuring grille airflows in HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S.; Wray, Craig P.; Guillot, Cyril; Masson, S.

    2003-08-01

    In this report, we discuss the accuracy of flow hoods for residential applications, based on laboratory tests and field studies. The results indicate that commercially available hoods are often inadequate to measure flows in residential systems, and that there can be a wide range of performance between different flow hoods. The errors are due to poor calibrations, sensitivity of existing hoods to grille flow non-uniformities, and flow changes from added flow resistance. We also evaluated several simple techniques for measuring register airflows that could be adopted by the HVAC industry and homeowners as simple diagnostics that are often as accurate as commercially available devices. Our test results also show that current calibration procedures for flow hoods do not account for field application problems. As a result, organizations such as ASHRAE or ASTM need to develop a new standard for flow hood calibration, along with a new measurement standard to address field use of flow hoods.

  3. Characterization and control of the microbial community affiliated with copper or aluminum heat exchangers of HVAC systems.

    Science.gov (United States)

    Schmidt, Michael G; Attaway, Hubert H; Terzieva, Silva; Marshall, Anna; Steed, Lisa L; Salzberg, Deborah; Hamoodi, Hameed A; Khan, Jamil A; Feigley, Charles E; Michels, Harold T

    2012-08-01

    Microbial growth in heating ventilation and air-conditioning (HVAC) systems with the subsequent contamination of indoor air is of increasing concern. Microbes and the subsequent biofilms grow easily within heat exchangers. A comparative study where heat exchangers fabricated from antimicrobial copper were evaluated for their ability to limit microbial growth was conducted using a full-scale HVAC system under conditions of normal flow rates using single-pass outside air. Resident bacterial and fungal populations were quantitatively assessed by removing triplicate sets of coupons from each exchanger commencing the fourth week after their installation for the next 30 weeks. The intrinsic biofilm associated with each coupon was extracted and characterized using selective and differential media. The predominant organisms isolated from aluminum exchangers were species of Methylobacterium of which at least three colony morphologies and 11 distinct PFGE patterns we found; of the few bacteria isolated from the copper exchangers, the majority were species of Bacillus. The concentrations and type of bacteria recovered from the control, aluminum, exchangers were found to be dependent on the type of plating media used and were 11,411-47,257 CFU cm(-2) per coupon surface. The concentration of fungi was found to average 378 CFU cm(-2). Significantly lower concentrations of bacteria, 3 CFU cm(-2), and fungi, 1 CFU cm(-2), were recovered from copper exchangers regardless of the plating media used. Commonly used aluminum heat exchangers developed stable, mixed, bacterial/fungal biofilms in excess of 47,000 organisms per cm(2) within 4 weeks of operation, whereas the antimicrobial properties of metallic copper were able to limit the microbial load affiliated with the copper heat exchangers to levels 99.97 % lower during the same time period.

  4. HVAC Trials.

    Science.gov (United States)

    Greim, Clifton W.; D'Angelo, David

    1999-01-01

    Explains how commissioning can help to ensure that all components in a new heating, ventilation, and air conditioning system will work together as designed. Bowdoin College's experience with commissioning is highlighted. (GR)

  5. HVAC Trials.

    Science.gov (United States)

    Greim, Clifton W.; D'Angelo, David

    1999-01-01

    Explains how commissioning can help to ensure that all components in a new heating, ventilation, and air conditioning system will work together as designed. Bowdoin College's experience with commissioning is highlighted. (GR)

  6. Consistent Design of Dependable Control Systems

    DEFF Research Database (Denmark)

    Blanke, M.

    1996-01-01

    Design of fault handling in control systems is discussed, and a method for consistent design is presented.......Design of fault handling in control systems is discussed, and a method for consistent design is presented....

  7. Draft PRN 2006-A: Use of Antimicrobial Pesticide Products in Heating, Ventilation, Air Conditioning and Refrigeration Systems (HVAC&R)

    Science.gov (United States)

    This draft notice provides guidance to registrants of EPA-registered antimicrobial products whose labels bear general directions related to hard, non-porous or porous surfaces, but which are not but which are not specifically registered for HVAC uses.

  8. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    Energy Technology Data Exchange (ETDEWEB)

    Shendell, Derek Garth [Univ. of California, Los Angeles, CA (United States)

    2003-01-01

    The prevalence of prefabricated, portable classrooms (portables, relocatables, RCs) has increased due to class size reduction initiatives and limited resources. Classroom mechanical wall-mount heating, ventilation, and air conditioning (HVAC) systems may function improperly or not be maintained; lower ventilation rates may impact indoor air and environmental quality (IEQ). Materials in portables may off-gas volatile organic compounds (VOCs), including formaldehyde, as a function of age, temperature, and humidity. For a pilot study, public K-12 schools located in or serving target areas within five Los Angeles County communities were identified. In two communities where school districts (SD) consented, 1-3 randomly selected portables, one newer and one older, and one main building control classroom from each participating school were included. Sampling was conducted over a five-day school week in the cooling and heating seasons, or repeated twice in the cooling season. Measurements included passive samplers for VOCs, formaldehyde and acetaldehyde, and air exchange rate (AER) calculation; indoor air temperature and humidity; technician walk-through surveys; an interview questionnaire above HVAC system operation and maintenance (O and M). For an intervention study evaluating advanced HVAC technologies in comparison to the common conventional technology, and materials for source reduction of VOCs, four RC were manufactured and located in pairs at two schools in two recruited Northern California SD in different climate zones. RCs were built with the two HVAC systems, cabinetry and conduit for monitoring equipment, and standard or advanced interior finish materials. Each RC was its own control in a case-crossover design--HVAC systems alternately operated for 1-2 week intervals in the 2001-02 school year, with IEQ monitoring including aldehyde and indoor air temperature and humidity data. Measured classroom AER were low, formaldehyde concentrations were below the state

  9. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    OpenAIRE

    Mohamad Ramadan; Mostafa Gad El Rab; Mahmoud Khaled

    2015-01-01

    In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particu...

  10. Fault Diagnosis in HVAC Chillers

    Science.gov (United States)

    Choi, Kihoon; Namuru, Setu M.; Azam, Mohammad S.; Luo, Jianhui; Pattipati, Krishna R.; Patterson-Hine, Ann

    2005-01-01

    Modern buildings are being equipped with increasingly sophisticated power and control systems with substantial capabilities for monitoring and controlling the amenities. Operational problems associated with heating, ventilation, and air-conditioning (HVAC) systems plague many commercial buildings, often the result of degraded equipment, failed sensors, improper installation, poor maintenance, and improperly implemented controls. Most existing HVAC fault-diagnostic schemes are based on analytical models and knowledge bases. These schemes are adequate for generic systems. However, real-world systems significantly differ from the generic ones and necessitate modifications of the models and/or customization of the standard knowledge bases, which can be labor intensive. Data-driven techniques for fault detection and isolation (FDI) have a close relationship with pattern recognition, wherein one seeks to categorize the input-output data into normal or faulty classes. Owing to the simplicity and adaptability, customization of a data-driven FDI approach does not require in-depth knowledge of the HVAC system. It enables the building system operators to improve energy efficiency and maintain the desired comfort level at a reduced cost. In this article, we consider a data-driven approach for FDI of chillers in HVAC systems. To diagnose the faults of interest in the chiller, we employ multiway dynamic principal component analysis (MPCA), multiway partial least squares (MPLS), and support vector machines (SVMs). The simulation of a chiller under various fault conditions is conducted using a standard chiller simulator from the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE). We validated our FDI scheme using experimental data obtained from different types of chiller faults.

  11. Fault Diagnosis in HVAC Chillers

    Science.gov (United States)

    Choi, Kihoon; Namuru, Setu M.; Azam, Mohammad S.; Luo, Jianhui; Pattipati, Krishna R.; Patterson-Hine, Ann

    2005-01-01

    Modern buildings are being equipped with increasingly sophisticated power and control systems with substantial capabilities for monitoring and controlling the amenities. Operational problems associated with heating, ventilation, and air-conditioning (HVAC) systems plague many commercial buildings, often the result of degraded equipment, failed sensors, improper installation, poor maintenance, and improperly implemented controls. Most existing HVAC fault-diagnostic schemes are based on analytical models and knowledge bases. These schemes are adequate for generic systems. However, real-world systems significantly differ from the generic ones and necessitate modifications of the models and/or customization of the standard knowledge bases, which can be labor intensive. Data-driven techniques for fault detection and isolation (FDI) have a close relationship with pattern recognition, wherein one seeks to categorize the input-output data into normal or faulty classes. Owing to the simplicity and adaptability, customization of a data-driven FDI approach does not require in-depth knowledge of the HVAC system. It enables the building system operators to improve energy efficiency and maintain the desired comfort level at a reduced cost. In this article, we consider a data-driven approach for FDI of chillers in HVAC systems. To diagnose the faults of interest in the chiller, we employ multiway dynamic principal component analysis (MPCA), multiway partial least squares (MPLS), and support vector machines (SVMs). The simulation of a chiller under various fault conditions is conducted using a standard chiller simulator from the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE). We validated our FDI scheme using experimental data obtained from different types of chiller faults.

  12. Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

    CERN Document Server

    2012-01-01

    Proposal for the award of a contract for the design, supply, installation and commissioning of a Heating, Ventilation and Air-Conditioning (HVAC) system for the computer room of the CERN Control Centre

  13. Implementation of PFC (Predictive Functional Control) in a PLC (Programmable Logic Controller) for a HVAC (Heating, Ventilation and Air Conditioning) system

    Science.gov (United States)

    Kreutz, M.; Richalet, J.; Mocha, K.; Haber, R.

    2014-12-01

    HVAC systems of industrial buildings consume a lot of energy. Therefore it is important to know the performance of these systems and strategies to optimize the hardware and the control. Tackling the temperature control of the HVAC system promises quick savings by tuning the control within specified tolerance limits, which mostly can be done by low investment. This paper mainly deals with the implementation strategy of a new controller in a PLC using the predictive functional control for temperature control. The different stages of the implementation from the simulation over the SCL code till to the real-time operation are presented. A bumpless switch between the PI(D) and the PFC control was realized, as well.

  14. HVAC; Heating, Ventilation, Air Conditioning - Aerosol Duct Sealant

    Science.gov (United States)

    2016-09-01

    Approved for public release: distribution unlimited TDS-NAVFAC-EXWC-PW-1603 Sep 2016 HVAC ; Heating, Ventilation, Air Conditioning - Aerosol...energy consumption, depending on the HVAC system type and the location of the ducts that were sealed. The cost effectiveness of the technology is...Although several studies have been done on the effectiveness of sealing leaky HVAC ductwork with aerosol duct sealant, few studies have been done on

  15. LSSVM predictive control for HVAC system with PSO algorithm%基于PSO算法的HVAC系统LSSVM预测控制

    Institute of Scientific and Technical Information of China (English)

    邹木春; 龙文

    2012-01-01

    For the system of heating, ventilating and air-conditioning (HVAC), a nonlinear predictive control algorithm based on particle swarm optimization (PSO) and least square support vector machine (LSSVM) was proposed. It utilizes LSSVM to estimate the HVAC system model and forecast the output value, reducing the error in output feedback and error correction. A new weighted predictive control performance index is formulated. The optimal control values of the nonlinear system are obtained by the rolling optimization of PSO algorithm. An optimal control system is designed to control a HVAC system; simulation results show that the proposed nonlinear predictive control algorithm is effective.%针对暖通空调(HVAC)系统,提出一种基于粒子群优化(PSO)算法和最小二乘支持向量机(LSSVM)的预测控制方法.该方法利用LSSVM建立HVAC系统预测模型并预测系统的输出值,引入输出反馈和偏差校正以克服模型失配等因素引起的预测误差,以此构造加权预测控制性能指标.由PSO算法滚动优化得到系统的最优控制量.利用该控制方法对一个HVAC系统进行仿真实验,结果表明该方法具有较好的控制效果.

  16. TNO HVAC facilities

    NARCIS (Netherlands)

    Hammink, H.A.J.

    2015-01-01

    TNO has extensive knowledge of heating, ventilation and air conditioning (HVAC), and can offer its services through theoretical studies, laboratory experiments and field measurements. This complete scope, made possible through our test facilities, enables the effective development of new products,

  17. A Novel Application of Thermoelectric Modules in an HVAC System Under Cold Climate Operation

    Science.gov (United States)

    Okuma, Toru; Radermacher, Reinhard; Hwang, Yunho

    2012-06-01

    A vapor compression cycle (VCC) with integrated thermoelectric (TE) modules to boost the heating capacity of the system in an energy-efficient way, especially for cold climate operation, is suggested in this paper. While a baseline heat pump (HP) cycle absorbs heat from a source through an evaporator, the proposed system utilizes TE modules as an intermediate (or third) stage of an otherwise two-stage vapor compression system with a vapor injection compressor. This increases the overall system efficiency and augments the system capacity through the high coefficient of performance (COP) of the TE for small temperature lift conditions. To demonstrate the concept, a prototype refrigerant-to-solid (TE) heat exchanger, consisting of TE modules and microchannel flat tubes, was designed and fabricated so that the whole system could realize an additional 1 kW of heating capacity compared with the baseline system. The TE heat exchanger was integrated into a residential HP unit that uses R-410A as a refrigerant, and the system was tested in a laboratory under the severe condition of -17.8°C, in order to investigate the capacity improvement and the overall COP. Finally, an application of this technique in an automotive heating, ventilating, and air-conditioning system with HFC134a working fluid has been studied for the purpose of providing supplemental heating for electric vehicles and hybrid electric vehicles by establishing a detailed simulation model of a HP system with the TE heat exchanger. Both the laboratory test and the calculation study show that a VCC with integrated TE modules has both reasonable efficiency and increased heating capacity.

  18. Sticky continuous processes have consistent price systems

    DEFF Research Database (Denmark)

    Bender, Christian; Pakkanen, Mikko; Sayit, Hasanjan

    Under proportional transaction costs, a price process is said to have a consistent price system, if there is a semimartingale with an equivalent martingale measure that evolves within the bid-ask spread. We show that a continuous, multi-asset price process has a consistent price system, under arb...

  19. Increasing energy efficiency of HVAC systems of buildings using phase change material

    Directory of Open Access Journals (Sweden)

    Lee Chusak, Jared Daiber, Ramesh Agarwal

    2012-01-01

    Full Text Available Using Computational Fluid Dynamics (CFD, four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare energy efficiency of (a an all-air overhead system, (b a combined all-air overhead and hydronic radiant system (chilled ceiling, (c an all-air raised floor system (displacement ventilation, and (d a combined displacement ventilation with a chilled ceiling. The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room. Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall. The second set of computations includes a phase change material layer between the glass window and the plastic shade. Results show substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.

  20. Increasing energy efficiency of HVAC systems of buildings using phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Chusak, Lee; Daiber, Jared; Agarwal, Ramesh [Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130 (United States)

    2012-07-01

    Using Computational Fluid Dynamics (CFD), four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare energy efficiency of (a) an all-air overhead system, (b) a combined all-air overhead and hydronic radiant system (chilled ceiling), (c) an all-air raised floor system (displacement ventilation), and (d) a combined displacement ventilation with a chilled ceiling. The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall. The second set of computations includes a phase change material layer between the glass window and the plastic shade. Results show substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.

  1. CONSISTENT AGGREGATION IN FOOD DEMAND SYSTEMS

    OpenAIRE

    Levedahl, J. William; Reed, Albert J.; Clark, J. Stephen

    2002-01-01

    Two aggregation schemes for food demand systems are tested for consistency with the Generalized Composite Commodity Theorem (GCCT). One scheme is based on the standard CES classification of food expenditures. The second scheme is based on the Food Guide Pyramid. Evidence is found that both schemes are consistent with the GCCT.

  2. Wireless Infrastructure for Performing Monitoring, Diagnostics, and Control HVAC and Other Energy-Using Systems in Small Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Patrick O' Neill

    2009-06-30

    This project focused on developing a low-cost wireless infrastructure for monitoring, diagnosing, and controlling building systems and equipment. End users receive information via the Internet and need only a web browser and Internet connection. The system used wireless communications for: (1) collecting data centrally on site from many wireless sensors installed on building equipment, (2) transmitting control signals to actuators and (3) transmitting data to an offsite network operations center where it is processed and made available to clients on the Web (see Figure 1). Although this wireless infrastructure can be applied to any building system, it was tested on two representative applications: (1) monitoring and diagnostics for packaged rooftop HVAC units used widely on small commercial buildings and (2) continuous diagnosis and control of scheduling errors such as lights and equipment left on during unoccupied hours. This project developed a generic infrastructure for performance monitoring, diagnostics, and control, applicable to a broad range of building systems and equipment, but targeted specifically to small to medium commercial buildings (an underserved market segment). The proposed solution is based on two wireless technologies. The first, wireless telemetry, is used for cell phones and paging and is reliable and widely available. This risk proved to be easily managed during the project. The second technology is on-site wireless communication for acquiring data from sensors and transmitting control signals. The technology must enable communication with many nodes, overcome physical obstructions, operate in environments with other electrical equipment, support operation with on-board power (instead of line power) for some applications, operate at low transmission power in license-free radio bands, and be low cost. We proposed wireless mesh networking to meet these needs. This technology is relatively new and has been applied only in research and tests

  3. Legionellosis prevention in building water and HVAC systems a practical guide for design, operation and maintenance to minimize the risk

    CERN Document Server

    Joppolo, Cesare Maria; Pitera, Luca Alberto; Angermann, Jean Pierre; Izard, Mark

    2013-01-01

    This Guidebook is a practical guide for design, operation and maintenance to minimize the risk of legionellosis in building water and HVAC systmes. It is devided into several themes such as: Air conditioning of the air (by water – humidification), Production of hot water for washing (fundamentally but not only hot water for washing) and Evaporative cooling tower.

  4. Multiyear Plan for Validation of EnergyPlus Multi-Zone HVAC System Modeling using ORNL's Flexible Research Platform

    Energy Technology Data Exchange (ETDEWEB)

    Im, Piljae [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bhandari, Mahabir S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); New, Joshua Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    This document describes the Oak Ridge National Laboratory (ORNL) multiyear experimental plan for validation and uncertainty characterization of whole-building energy simulation for a multi-zone research facility using a traditional rooftop unit (RTU) as a baseline heating, ventilating, and air conditioning (HVAC) system. The project’s overarching objective is to increase the accuracy of energy simulation tools by enabling empirical validation of key inputs and algorithms. Doing so is required to inform the design of increasingly integrated building systems and to enable accountability for performance gaps between design and operation of a building. The project will produce documented data sets that can be used to validate key functionality in different energy simulation tools and to identify errors and inadequate assumptions in simulation engines so that developers can correct them. ASHRAE Standard 140, Method of Test for the Evaluation of Building Energy Analysis Computer Programs (ASHRAE 2004), currently consists primarily of tests to compare different simulation programs with one another. This project will generate sets of measured data to enable empirical validation, incorporate these test data sets in an extended version of Standard 140, and apply these tests to the Department of Energy’s (DOE) EnergyPlus software (EnergyPlus 2016) to initiate the correction of any significant deficiencies. The fitness-for-purpose of the key algorithms in EnergyPlus will be established and demonstrated, and vendors of other simulation programs will be able to demonstrate the validity of their products. The data set will be equally applicable to validation of other simulation engines as well.

  5. TNO HVAC facilities

    NARCIS (Netherlands)

    Hammink, H.A.J.

    2015-01-01

    TNO has extensive knowledge of heating, ventilation and air conditioning (HVAC), and can offer its services through theoretical studies, laboratory experiments and field measurements. This complete scope, made possible through our test facilities, enables the effective development of new products, i

  6. On the existence of consistent price systems

    DEFF Research Database (Denmark)

    Bayraktar, Erhan; Pakkanen, Mikko S.; Sayit, Hasanjan

    2014-01-01

    We formulate a sufficient condition for the existence of a consistent price system (CPS), which is weaker than the conditional full support condition (CFS). We use the new condition to show the existence of CPSs for certain processes that fail to have the CFS property. In particular this condition...

  7. Computer Review Can Cut HVAC Energy Use

    Science.gov (United States)

    McClure, Charles J. R.

    1974-01-01

    A computerized review of construction bidding documents, usually done by a consulting engineer, can reveal how much money it will cost to operate various alternative types of HVAC equipment over a school's lifetime. The review should include a computerized load calculation, energy systems flow diagram, control system analysis, and a computerized…

  8. Computer Review Can Cut HVAC Energy Use

    Science.gov (United States)

    McClure, Charles J. R.

    1974-01-01

    A computerized review of construction bidding documents, usually done by a consulting engineer, can reveal how much money it will cost to operate various alternative types of HVAC equipment over a school's lifetime. The review should include a computerized load calculation, energy systems flow diagram, control system analysis, and a computerized…

  9. Geothermal HVAC Systems - A Business Case Analysis for Net Zero Plus

    Science.gov (United States)

    2009-03-01

    During the summer (or warm months), the system cools the building by pulling heat from the building , carrying it through the system and placing it in the...system and into the building or structure, Figure 4. Figure 3. The flow of energy during the Summer or warmer months (From Weigand, 2008...lives by reducing the need for traditional fuel transport. ( NetZero Plus – Joint Capability Technology Demonstration, March 2008) 13 C. THE

  10. An emulator for testing HVAC-control and energy management systems

    Science.gov (United States)

    Laitila, Paeivi; Kaerki, Satu; Piira, Kalevi; Katajisto, Katri; Kohonen, Reijo

    1992-02-01

    A technical description of an emulator for control and energy systems is presented. The emulator is made up of both physical components and numerical models programmed for a computer. In the emulator, the building and its internal and external heart and moisture loads are numerical models in all cases, if they are included in the system under study. The emulator can be used to study control equipment and energy management systems as well as other devices such as heat producing equipment. This is facilitated by the emulator's physical test equipment, which comprises an exchangeable heat producing device, two separate cooling water systems and their heat exchangers, and the mains water supply. At the heart of the emulator's ADP hardware are two microcomputers linked by an Ethernet line. The TRNSYS simulation software has been installed in one of the microcomputers, and the GENESIS process control program in the other. GENESIS is not needed for running the emulation. The process interface equipment and simulation software are connected to one another via their RS-232 serial ports. The performance functionality of the emulator was tested by investigating the control of an air conditioning system with a commercial controller (substation).

  11. A PID de-tuned method for multivariable systems, applied for HVAC plant

    Science.gov (United States)

    Ghazali, A. B.

    2015-09-01

    A simple yet effective de-tuning of PID parameters for multivariable applications has been described. Although the method is felt to have wider application it is simulated in a 3-input/ 2-output building energy management system (BEMS) with known plant dynamics. The controller performances such as the sum output squared error and total energy consumption when the system is at steady state conditions are studied. This tuning methodology can also be extended to reduce the number of PID controllers as well as the control inputs for specified output references that are necessary for effective results, i.e. with good regulation performances being maintained.

  12. Power System Technical Performance Issues Related to the Application of Long HVAC Cables

    DEFF Research Database (Denmark)

    Bak, Claus Leth

    The aim of this TB is to serve as a practical guide for preparing models and performing studies necessary during the assessment of the technical performance of HV/EHV systems with a large share of (long) AC cables. The brochure follows all phases of planning and analysis of a typical underground...

  13. A new design guideline for the heating and cooling curve in AHU units of HVAC systems

    NARCIS (Netherlands)

    Elkhuizen, P.A.; Peitsman, H.C.; Wienk, W.J.

    2003-01-01

    New Dutch office buildings are built under strict energy efficient legislation and are well equipped with insulation, condensing boilers, heat recovery systems, and so on. Despite this, many buildings do not have good energy efficiency and also do not meet comfort requirements. This has led to a lar

  14. Power System Technical Performance Issues Related to the Application of Long HVAC Cables

    DEFF Research Database (Denmark)

    Bak, Claus Leth

    The aim of this TB is to serve as a practical guide for preparing models and performing studies necessary during the assessment of the technical performance of HV/EHV systems with a large share of (long) AC cables. The brochure follows all phases of planning and analysis of a typical underground ...

  15. Assessing the potential of residential HVAC systems for demand-side management

    NARCIS (Netherlands)

    van der Klauw, Thijs; Hoogsteen, Gerwin; Gerards, Marco Egbertus Theodorus; Hurink, Johann L.; Feng, Xianyong; Hebner, Robert E.

    This paper investigates the potential of residential heating, ventilation and air conditioning systems to contribute to dynamic demand-side management. Thermal models for seven houses in Austin, Texas are developed with the goal of using them in a planning based demand-side management methodology.

  16. A new design guideline for the heating and cooling curve in AHU units of HVAC systems

    NARCIS (Netherlands)

    Elkhuizen, P.A.; Peitsman, H.C.; Wienk, W.J.

    2003-01-01

    New Dutch office buildings are built under strict energy efficient legislation and are well equipped with insulation, condensing boilers, heat recovery systems, and so on. Despite this, many buildings do not have good energy efficiency and also do not meet comfort requirements. This has led to a

  17. Experimental and numerical investigation of thermosyphone performance in HVAC system applications

    Science.gov (United States)

    Eidan, Adel A.; Najim, Saleh E.; Jalil, Jalal M.

    2016-12-01

    An experimental and numerical investigations are conducted on a Two Phase Closed Thermosyphon (TPCT) charged with six working fluids; namely (water, methanol, ethanol, acetone, butanol and R134a) with filling ratios (40, 50, 60, 70 and 100 %). The TPCT is made from a 0.016 m diameter copper tube, which consists of a 0.15 m evaporator, 0.1 m adiabatic and 0.15 m condenser sections, respectively. Thermocouples are located in the core and on the wall of the TPCT. The main objectives of the experimental investigation are to analyze the effect of the working fluid and filling ratio (liquid inventory) under heat inputs (20-120 W) with a fixed condenser cooling temperature of (25 °C) on the thermal performance of the TPCT. The results are compared with a simulation model using finite difference method in three dimensional cylindrical coordinates by using FORTRAN. The correlations of the phase change for the TPCT based on the theory of thermal resistance are used in the evaporator and condenser sections. The agreement between theoretical and experimental results is shown to be accurate within 10 %. The results showed that the maximum heat transport ability is associated with using of water and acetone where it is compared with other fluids under the same range of operating temperatures of 35-50 °C. This is the range between lowest and highest temperatures for the sub-tropical climates.

  18. Wireless Infrastructure for Performing Monitoring, Diagnostics, and Control HVAC and Other Energy-Using Systems in Small Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Patrick O' Neill

    2009-06-30

    This project focused on developing a low-cost wireless infrastructure for monitoring, diagnosing, and controlling building systems and equipment. End users receive information via the Internet and need only a web browser and Internet connection. The system used wireless communications for: (1) collecting data centrally on site from many wireless sensors installed on building equipment, (2) transmitting control signals to actuators and (3) transmitting data to an offsite network operations center where it is processed and made available to clients on the Web (see Figure 1). Although this wireless infrastructure can be applied to any building system, it was tested on two representative applications: (1) monitoring and diagnostics for packaged rooftop HVAC units used widely on small commercial buildings and (2) continuous diagnosis and control of scheduling errors such as lights and equipment left on during unoccupied hours. This project developed a generic infrastructure for performance monitoring, diagnostics, and control, applicable to a broad range of building systems and equipment, but targeted specifically to small to medium commercial buildings (an underserved market segment). The proposed solution is based on two wireless technologies. The first, wireless telemetry, is used for cell phones and paging and is reliable and widely available. This risk proved to be easily managed during the project. The second technology is on-site wireless communication for acquiring data from sensors and transmitting control signals. The technology must enable communication with many nodes, overcome physical obstructions, operate in environments with other electrical equipment, support operation with on-board power (instead of line power) for some applications, operate at low transmission power in license-free radio bands, and be low cost. We proposed wireless mesh networking to meet these needs. This technology is relatively new and has been applied only in research and tests

  19. An Integrated FDD System for HVAC&R Based on Virtual Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woohyun

    2017-01-22

    According to the U.S Department of Energy, space heating, ventilation and air conditioning system account for 40% of residential primary energy use and for 30% of primary energy use in commercial buildings. A study released by the Energy Information Administration indicated that packaged air conditioners are widely used in 46% of all commercial buildings in the U.S. This study indicates that the annual cooling energy consumption related to the packaged air conditioner is about 160 trillion Btus. Therefore, an automated FDD system that can automatically detect and diagnose faults and evaluate fault impacts has the potential for improving energy efficiency along with reducing service costs and comfort complaints. The primary bottlenecks to diagnostic implementation in the field are the high initial costs of additional sensors. To prevent those limitations, virtual sensors with low cost measurements and simple models are developed to estimate quantities that would be expensive and or difficult to measure directly. The use of virtual sensors can reduce costs compared to the use of real sensors and provide additional information for economic assessment. The virtual sensor can be embedded in a permanently installed control or monitoring system and continuous monitoring potentially leads to early detection of faults. The virtual sensors of individual equipment components can be integrated to estimate overall diagnostic information using the output of each virtual sensor.

  20. Consistence beats causality in recommender systems

    CERN Document Server

    Zhu, Xuzhen; Hu, Zheng; Zhang, Ping; Zhou, Tao

    2015-01-01

    The explosive growth of information challenges people's capability in finding out items fitting to their own interests. Recommender systems provide an efficient solution by automatically push possibly relevant items to users according to their past preferences. Recommendation algorithms usually embody the causality from what having been collected to what should be recommended. In this article, we argue that in many cases, a user's interests are stable, and thus the previous and future preferences are highly consistent. The temporal order of collections then does not necessarily imply a causality relationship. We further propose a consistence-based algorithm that outperforms the state-of-the-art recommendation algorithms in disparate real data sets, including \\textit{Netflix}, \\textit{MovieLens}, \\textit{Amazon} and \\textit{Rate Your Music}.

  1. 基于LPNTI-PLC的HVAC系统反馈控制%HVAC System Feedback Control Method Based on LPNTI-PLC Research

    Institute of Scientific and Technical Information of China (English)

    王攀藻; 张华

    2015-01-01

    针对变风量中央空调系统HVAC,频繁工作、多干扰和控制滞后以及被控对象参数未知或是时变的情况,传统的控制方法不能够很好的消除干扰和控制延迟导致系统不能很好地进行反馈调节,控制效果欠佳。提出了基于拉氏正反变换积分PLC的HVAC系统反馈控制方法,该方法在多动态工况下的HVAC系统的应用,能够提高控制精度,根据系统输入、输出变化量阶跃响应,建立LPNTI积分控制模型,只要模型选取合适的参数,就能消除静差和余差,避免饱和超调,而且进一步校正模型的稳定性,使得适应HVAC系统动态工况,同时,基于鲁棒性能指标,控制方法设计了PLC控制模型。实验结果表明,此方法比传统的控制方法更具有优越性,体现了有效性和实用性,对提升HVAC系统的控制精度和响应速度具有较大的帮助。%For HVAC vav central air-conditioning system, frequently, interference and control work lag and the situation of the controlled object parameters are unknown or time-varying, traditional control methods can't eliminate interference and well control delay cause system can't good feedback adjustment, the control effect. And reverse transformation is proposed based on The Laplace integral PLC of The HVAC system feedback control method, The method in The application of dy⁃namic conditions of HVAC system, can improve The control precision, based on The system input and output variation step response, LPNTI integral control model is set up, as long as The model to select The appropriate parameters, can eliminate The static error and residual, avoid saturated overshoot, and further The stability of The calibration model, make to adapt to The HVAC system dynamic condition, at The same time, based on The robust performance index, The control method to de⁃sign The PLC control model. The experimental results show that this method is more superiority than

  2. Model Predictive Control of HVAC Systems: Implementation and Testing at the University of California, Merced

    Energy Technology Data Exchange (ETDEWEB)

    Haves, Phillip; Hencey, Brandon; Borrell, Francesco; Elliot, John; Ma, Yudong; Coffey, Brian; Bengea, Sorin; Wetter, Michael

    2010-06-29

    A Model Predictive Control algorithm was developed for the UC Merced campus chilled water plant. Model predictive control (MPC) is an advanced control technology that has proven successful in the chemical process industry and other industries. The main goal of the research was to demonstrate the practical and commercial viability of MPC for optimization of building energy systems. The control algorithms were developed and implemented in MATLAB, allowing for rapid development, performance, and robustness assessment. The UC Merced chilled water plant includes three water-cooled chillers and a two million gallon chilled water storage tank. The tank is charged during the night to minimize on-peak electricity consumption and take advantage of the lower ambient wet bulb temperature. The control algorithms determined the optimal chilled water plant operation including chilled water supply (CHWS) temperature set-point, condenser water supply (CWS) temperature set-point and the charging start and stop times to minimize a cost function that includes energy consumption and peak electrical demand over a 3-day prediction horizon. A detailed model of the chilled water plant and simplified models of the buildings served by the plant were developed using the equation-based modeling language Modelica. Steady state models of the chillers, cooling towers and pumps were developed, based on manufacturers performance data, and calibrated using measured data collected and archived by the control system. A detailed dynamic model of the chilled water storage tank was also developed and calibrated. Simple, semi-empirical models were developed to predict the temperature and flow rate of the chilled water returning to the plant from the buildings. These models were then combined and simplified for use in a model predictive control algorithm that determines the optimal chiller start and stop times and set-points for the condenser water temperature and the chilled water supply temperature. The

  3. Consistent thermodynamic properties of lipids systems

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Sarup, Bent

    Physical and thermodynamic properties of pure components and their mixtures are the basic requirement for process design, simulation, and optimization. In the case of lipids, our previous works[1-3] have indicated a lack of experimental data for pure components and also for their mixtures...... different pressures, with azeotrope behavior observed. Available thermodynamic consistency tests for TPx data were applied before performing parameter regressions for Wilson, NRTL, UNIQUAC and original UNIFAC models. The relevance of enlarging experimental databank of lipids systems data in order to improve...

  4. Solar Trigeneration: a Transitory Simulation of HVAC Systems Using Different Typologies of Hybrid Panels

    Directory of Open Access Journals (Sweden)

    Alejandro del Amo Sancho

    2014-03-01

    Full Text Available The high energy demand on buildings requires efficient installations and the integration of renewable energy to achieve the goal of reducing energy consumption using traditional energy sources. Usually, solar energy generation and heating loads have different profiles along a day and their maximums take place at different moments. In addition, in months in which solar production is higher, the heating demands are the minimum (hot water is consumed only domestically in summer. Cooling machines (absorption and adsorption allow using thermal energy to chill a fluid. This heat flow rate could be recovered from solar collectors or any other heat source. The aim of this study is to integrate different typologies of solar hybrid (photovoltaic and thermal collectors with cooling machines getting solar trigeneration and concluding the optimal combination for building applications. The heat recovered from the photovoltaic module is used to provide energy to these cooling machines getting a double effect: to get a better efficiency on PV modules and to cool the building. In this document the authors analyse these installations, their operating conditions, dimensions and parameters, in order to get the optimal installation in three different European cities. This work suggests that in a family house in Madrid, the optimal combination is to use CPVT with azimuthally tracking and absorption machine. In this case, the solar trigeneration system using 55 m2 of collector area saves the cooling loads and 79% of the heating load in the house round the year.

  5. HVAC Equipment Design Options for Near-Zero-Energy Homes (NZEH) -A Stage 2 Scoping Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D [ORNL

    2005-11-01

    Although the energy efficiency of heating, ventilating, and air-conditioning (HVAC) equipment has increased substantially in recent years, new approaches are needed to continue this trend. Conventional unitary equipment and system designs have matured to a point where cost-effective, dramatic efficiency improvements that meet near-zero-energy housing (NZEH) goals require a radical rethinking of opportunities to improve system performance. The large reductions in HVAC energy consumption necessary to support the NZEH goals require a systems-oriented analysis approach that characterizes each element of energy consumption, identifies alternatives, and determines the most cost-effective combination of options. In particular, HVAC equipment must be developed that addresses the range of special needs of NZEH applications in the areas of reduced HVAC and water heating energy use, humidity control, ventilation, uniform comfort, and ease of zoning. This report describes results of a scoping assessment of HVAC system options for NZEH homes. ORNL has completed a preliminary adaptation, for consideration by The U.S. Department of Energy, Energy Efficiency and Renewable Energy Office, Building Technologies (BT) Program, of Cooper's (2001) stage and gate planning process to the HVAC and Water Heating element of BT's multi-year plan, as illustrated in Figure 1. In order to adapt to R&D the Cooper process, which is focused on product development, and to keep the technology development process consistent with an appropriate role for the federal government, the number and content of the stages and gates needed to be modified. The potential federal role in technology development involves 6 stages and 7 gates, but depending on the nature and status of the concept, some or all of the responsibilities can flow to the private sector for product development beginning as early as Gate 3. In the proposed new technology development stage and gate sequence, the Stage 2 &apos

  6. Cutting the cost of hospital HVAC.

    Science.gov (United States)

    Ruddell, Steve

    2011-09-01

    Steve Ruddell, head of global marketing, Motors & Generators, at ABB, emphasises the importance of a good motor management and maintenance policy in getting the best performance from, and reducing the energy consumption of, hospitals' HVAC systems, also explaining why investing in energy-efficient, low voltage drives, and high efficiency electric motors, to control such equipment, can pay major dividends for estates and facilities teams.

  7. Evaluating performance indices of a shopping centre and implementing HVAC control principles to minimize energy usage

    OpenAIRE

    Canbay, Çağlar Selçuk; Hepbaşlı, Arif; Gökçen Akkurt, Gülden

    2004-01-01

    Heating, ventilating and air-conditioning (HVAC) systems in buildings must be integrated with an efficient control scheme to maintain comfort under any load conditions. Efficient HVAC control is often the most cost-effective option to improve the energy efficiency of a building. However, HVAC processes are non-linear, and characteristics change on a seasonal basis so the effect of changing the control strategy is usually difficult to predict. The present study aims to reduce energy consumptio...

  8. Information, Consistent Estimation and Dynamic System Identification.

    Science.gov (United States)

    1976-11-01

    the chesis . The rest of Chapter 4 4 is believed to be of theoretical interest and also of practical value, I which is demonstrated in sections 6.1...in the mean of the identification procedures at a certain rate. The condition in (6.3) also involves the system’s coefficients and thus, the selected

  9. Chapter 19: HVAC Controls (DDC/EMS/BAS) Evaluation Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Romberger, J.

    2014-11-01

    The HVAC Controls Evaluation Protocol is designed to address evaluation issues for direct digital controls/energy management systems/building automation systems (DDC/EMS/BAS) that are installed to control heating, ventilation, and air-conditioning (HVAC) equipment in commercial and institutional buildings. (This chapter refers to the DDC/EMS/BAS measure as HVAC controls.) This protocol may also be applicable to industrial facilities such as clean rooms and labs, which have either significant HVAC equipment or spaces requiring special environmental conditions. This protocol addresses only HVAC-related equipment and the energy savings estimation methods associated with installing such control systems as an energy efficiency measure. The affected equipment includes: Air-side equipment (air handlers, direct expansion systems, furnaces, other heating- and cooling-related devices, terminal air distribution equipment, and fans); Central plant equipment (chillers, cooling towers, boilers, and pumps). These controls may also operate or affect other end uses, such as lighting, domestic hot water, irrigation systems, and life safety systems such as fire alarms and other security systems. Considerable nonenergy benefits, such as maintenance scheduling, system component troubleshooting, equipment failure alarms, and increased equipment lifetime, may also be associated with these systems. When connected to building utility meters, these systems can also be valuable demand-limiting control tools. However, this protocol does not evaluate any of these additional capabilities and benefits.

  10. Energy-Smart Choices for Schools. An HVAC Comparison Tool. [CD-ROM].

    Science.gov (United States)

    Geothermal Heat Pump Consortium, Inc., Washington, DC.

    A CD ROM program provides comparison construction cost capabilities for heating, ventilation, and air conditioning (HVAC) systems in educational facilities. The program combines multiple types of systems with square footage data on low and high construction cost and school size to automatically calculate HVAC comparative construction costs. (GR)

  11. Energy-Smart Choices for Schools. An HVAC Comparison Tool. [CD-ROM].

    Science.gov (United States)

    Geothermal Heat Pump Consortium, Inc., Washington, DC.

    A CD ROM program provides comparison construction cost capabilities for heating, ventilation, and air conditioning (HVAC) systems in educational facilities. The program combines multiple types of systems with square footage data on low and high construction cost and school size to automatically calculate HVAC comparative construction costs. (GR)

  12. Development of a system for detection and diagnosis of errors in the operation of space HVAC systems; Entwicklung eines Systems zur Erkennung und Diagnose von Fehlern beim Betrieb von HLK-Anlagen

    Energy Technology Data Exchange (ETDEWEB)

    Bach, H.; Bauer, M.; Grob, R.F. [Stuttgart Univ. (Germany). Lehrstuhl fuer Heiz- und Raumlufttechnik

    1997-12-31

    Buildings with heating and space HVAC systems require considerable automatic control effort to ensure engergy-efficient operation. Faults are only to be avoided by the use of automatic fault detection systems. The contribution describes the procedure adopted in operation monitoring, the IKE system for fault detection and diagnosis, and the evaluation of the FDD system. (MSK) [Deutsch] Gebaeude mit heiz-und raumlufttechnischen Anlagen erfordern bei energetisch rationellem Bertrieb einen grossen Aufwand an Steuerungs-und Regelungstechnik. Um ohne Fehler zu arbeiten erfordert diese Steuerungs-und Regelungstechnik den Einsatz von automatischen Fehlererkennungssystemen. Im Folgenden werden die Vorgehensweise bei der Betriebsueberwachung, das IKE-System zur Fehlererkennung und Diagnose sowie die Evaluierung des FDD-Systems (Fault Detection and Diagnosis System) erlaeutert.

  13. The HVAC Control Technology Making Energy Saving Compatible with Comfort

    Science.gov (United States)

    Takagi, Yasuo; Yonezawa, Kenzo; Murayama, Dai; Nishimura, Nobutaka; Hanada, Yuuichi; Yamazaki, Kenichi

    The new air-conditioning control technology for the energy saving for buildings is proposed. The method is mainly focused on the compatibility of energy savings and comfort. The energy saving is achieved through the next generation air handling unit that controls room humidity without energy loss and the optimal operation of HVAC (Heating, Ventilating and air-conditioning) system, manipulating the supplying airflow temperature to the rooms, room temperature and the humidity. The comfort is kept by the index (PMV: Predicted Mean Vote) that calculated with room temperature, humidity, radiation temperature, wind velocity and so on. In order to find the HVAC system operation conditions that satisfy the comfort and energy saving at the same time, very large-scale nonlinear programming with nonlinear constraints must be solved on real time basis. To make the programming of the system practical, the driving function loaded onto a control computer is introduced. The function is made by the spline interpolation to achieve calculation stable and to adapt to various HVAC operation modes. The effectiveness of the HVAC control technology is proved through a building HVAC data and the simulations using the data.

  14. Building America Top Innovations 2014 Profile: HVAC Cabinet Air Leakage Test Method

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-11-01

    This 2014 Top Innovation profile describes Building America-funded research by teams and national laboratories that resulted in the development of an ASHRAE standard and a standardized testing method for testing the air leakage of HVAC air handlers and furnace cabinets and has spurred equipment manufacturers to tighten the cabinets they use for residential HVAC systems.

  15. Active noise control: A tutorial for HVAC designers

    Energy Technology Data Exchange (ETDEWEB)

    Gelin, L.J.

    1997-08-01

    This article will identify the capabilities and limitations of ANC in its application to HVAC noise control. ANC can be used in ducted HVAC systems to cancel ductborne, low-frequency fan noise by injecting sound waves of equal amplitude and opposite phase into an air duct, as close as possible to the source of the unwanted noise. Destructive interference of the fan noise and injected noise results in sound cancellation. The noise problems that it solves are typically described as rumble, roar or throb, all of which are difficult to address using traditional noise control methods. This article will also contrast the use of active against passive noise control techniques. The main differences between the two noise control measures are acoustic performance, energy consumption, and design flexibility. The article will first present the fundamentals and basic physics of ANC. The application to real HVAC systems will follow.

  16. Job Prospects in HVAC Engineering.

    Science.gov (United States)

    Basta, Nicholas

    1985-01-01

    Although heating, ventilation, and air conditioning (HVAC) engineering degrees are not offered, there is a serious need for specialists and consultants in this area (since most have been trained as mechanical engineers). Opportunities exist for individuals possessing a customer-oriented attitude, with knowledge in computerized controls, innovative…

  17. Job Prospects in HVAC Engineering.

    Science.gov (United States)

    Basta, Nicholas

    1985-01-01

    Although heating, ventilation, and air conditioning (HVAC) engineering degrees are not offered, there is a serious need for specialists and consultants in this area (since most have been trained as mechanical engineers). Opportunities exist for individuals possessing a customer-oriented attitude, with knowledge in computerized controls, innovative…

  18. On multidimensional consistent systems of asymmetric quad-equations

    CERN Document Server

    Boll, Raphael

    2012-01-01

    Multidimensional Consistency becomes more and more important in the theory of discrete integrable systems. Recently, we gave a classification of all 3D consistent 6-tuples of equations with the tetrahedron property, where several novel asymmetric systems have been found. In the present paper we discuss higher-dimensional consistency for 3D consistent systems coming up with this classification. In addition, we will give a classification of certain 4D consistent systems of quad-equations. The results of this paper allow for a proof of the Bianchi permutability among other applications.

  19. Building Assessment Survey and Evaluation Study Summarized Data - HVAC Characteristics

    Science.gov (United States)

    In the Building Assessment Survey and Evaluation (BASE) Study Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues was acquired by examining the building plans, conducting a building walk-through, and speaking with the building owner, manager, and/or operator.

  20. Experimental study on HVAC sound parameters

    Science.gov (United States)

    Bujoreanu, C.; Benchea, M.

    2016-08-01

    HVAC system represent major source of buildings internal noise and therefore they are designed to provide a human acoustic comfort besides the thermal and air quality requirements. The paper experimentally investigates three types of commercial air handler units (AHU) with different ducts cross-section sizes and inlet-outlet configuration. The measurements are performed in an anechoic room. The measurements are carried out at different fan's speeds, ranging the power-charge from 30-100% while the duct air flow is slowly adjusted from full open to full closed, between 0-500 Pa. The sound pressure levels of the radiant units are rated using NR curves. Also, the supply and the outdoor ducts sound levels are compared in order to point the frequencies where the noise must be reduced. Third-octave band analysis of random noise of an air handling unit from a HVAC system is realized, using measurement procedures that agrees the requirements of the ISO 3744:2011 and ISO 5136:2010 standards. The comparatively results highlight the effects of the geometry, air flow pressure and power-charging dependencies upon the sound level. This is the start for a noise reduction strategy.

  1. Analysis and control of the effects of over excitation limiters on the stability of the Itaipu HVAC transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Jardim, J.L.; Macedo, N.J.; Santo, S.E.; Praca, A.S. [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The effect of over excitation limiters on power system voltage stability is presented in this paper. A linear analysis based on system eigenvalues for various operating conditions shows that voltage collapse is essentially a dynamic phenomenon. Time simulations using digital tools and real-time simulator were performed to verify lin ear results and study large disturbances. A control system designed to keep system in secure region is proposed. (author) 3 refs., 9 figs.

  2. "暖通空调工程设计方法与系统分析"课程教学方法探讨%Discussion on"HVAC Engineering Design and System Analysis"Teaching Method

    Institute of Scientific and Technical Information of China (English)

    夏燚

    2015-01-01

    本文用"思维导图"梳理暖通空调工程设计课程与专业基础课的内在联系,提出用"工科思维"模式学习该课程,把专业基础课的"知识线"构织成该课程的"知识网".本文用"暖通空调工程设计过程图"帮助学生从全局上掌握该"知识网",采用"案例教学"帮助学生掌握暖通空调工程设计技能,帮助学生实现由专业知识向解决工程问题专业技能的转变,从而达到本课程的教学目的.%In this paper, we use"the mind map"to comb the relationship between the course of"HVAC engineering de-sign method and system analysis"and the specialized basic course. The"engineering thinking mode"is put forward to study the course, and use the"knowledge line"of the specialized basic course to construct the"knowledge network". We use the"HVAC engineering design flowchart"to help students master the"knowledge network"from the global, using"the case teaching method"to help students master the skills of HVAC design to help students realize the transformation from knowledge to skills, so as to achieve the purpose of teaching the course.

  3. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  4. Air conditioning and energy conservation. Improved space HVAC systems. Case studies: Office buildings, hotels, shopping centers, skyscrapers, industrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Heiner, H.

    1988-08-01

    Rising energy prices and an increasing demand for comfortable rooms account for the importance attached to the windows and glass used for office buildings, hotels and industrial plants. Both windows and glass have a considerable influence on the thermal behavior and air conditioning of buildings. Among the latest developments are precious metal-coated insulating panes. Selected gases allow to reduce the total thickness of insulating glass and improve noise insulation. The case studies presented refer to the energy-saving air conditioning and space heating, heat recovery and cooling of rooms as well as to the respective control systems. Investigations into the specific energy consumption of building shells reveal the considerable space/tap water heating energy conservation potentials remaining to be utilized.

  5. Workplace Trends In HVAC/R

    Science.gov (United States)

    Strang, Lynn; Todd, CeCe

    2013-01-01

    This article presents trends in the heating, ventilation, air conditioning and refrigeration (HVAC/R) industry, with an emphasis on the importance of technician training programs as exemplified at the East Valley Institute of Technology (EVIT) in Mesa, Arizona. The article states that HVAC workers are increasingly helping their consumers "go…

  6. Workplace Trends In HVAC/R

    Science.gov (United States)

    Strang, Lynn; Todd, CeCe

    2013-01-01

    This article presents trends in the heating, ventilation, air conditioning and refrigeration (HVAC/R) industry, with an emphasis on the importance of technician training programs as exemplified at the East Valley Institute of Technology (EVIT) in Mesa, Arizona. The article states that HVAC workers are increasingly helping their consumers "go…

  7. Impact of the duct static pressure reset control strategy on the energy consumption by the HVAC system

    Directory of Open Access Journals (Sweden)

    Walaszczyk Juliusz

    2017-01-01

    Full Text Available This article addresses different duct static pressure control strategies which could be implemented in variable air volume air-conditioning systems (VAV. Two pressure reset control strategies are compared to the commonly used control solution based on the “Constant static pressure” method. First pressure reset control strategy, known as PID Control, uses signals from VAV boxes controllers to reset duct static pressure in a way that one of the VAV dampers is maintained almost entirely open. Second strategy decreases static pressure setpoint until an adjustable number of pressure requests occur. As a response to the certain amount of requests, static pressure setpoint is increased. This strategy is called Trim & Respond. Both static pressure reset control strategies described in this paper are considered to have more significant potential for energy savings than the “Constant static pressure” method. In order to validate this potential, several simulations for different control strategies were carried out and the obtained results are compared and analysed. The theoretical limit of the energy savings - set of the optimal control actions, was estimated with Nelder-Mead algorithm and also presented in this article. General description of the static pressure control strategies "Constant static pressure", PID Control and Trim & Respond is given.

  8. Novel Methods for Activity Classification and Occupany Prediction Enabling Fine-grained HVAC Control

    OpenAIRE

    Rana, Rajib; Kusy, Brano; Wall, Josh; Hu, Wen

    2014-01-01

    Much of the energy consumption in buildings is due to HVAC systems, which has motivated several recent studies on making these systems more energy- efficient. Occupancy and activity are two important aspects, which need to be correctly estimated for optimal HVAC control. However, state-of-the-art methods to estimate occupancy and classify activity require infrastructure and/or wearable sensors which suffers from lower acceptability due to higher cost. Encouragingly, with the advancement of th...

  9. SEED: Public Energy and Environment Dataset for Optimizing HVAC Operation in Subway Stations

    OpenAIRE

    Wang, Yongcai; Feng, Haoran; Qi, Xiao

    2013-01-01

    For sustainability and energy saving, the problem to optimize the control of heating, ventilating, and air-conditioning (HVAC) systems has attracted great attentions, but analyzing the signatures of thermal environments and HVAC systems and the evaluation of the optimization policies has encountered inefficiency and inconvenient problems due to the lack of public dataset. In this paper, we present the Subway station Energy and Environment Dataset (SEED), which was collected from a line of Bei...

  10. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  11. Consistency in experiments on multistable driven delay systems

    Science.gov (United States)

    Oliver, Neus; Larger, Laurent; Fischer, Ingo

    2016-10-01

    We investigate the consistency properties in the responses of a nonlinear delay optoelectronic intensity oscillator subject to different drives, in particular, harmonic and self-generated waveforms. This system, an implementation of the Ikeda oscillator, is operating in a closed-loop configuration, exhibiting its autonomous dynamics while the drive signals are additionally introduced. Applying the same drive multiple times, we compare the dynamical responses of the optoelectronic oscillator and quantify the degree of consistency among them via their correlation. Our results show that consistency is not restricted to conditions close to the first Hopf bifurcation but can be found in a broad range of dynamical regimes, even in the presence of multistability. Finally, we discuss the dependence of consistency on the nature of the drive signal.

  12. Energy-efficient HVAC design an essential guide for sustainable building

    CERN Document Server

    Khazaii, Javad

    2014-01-01

    This book provides readers with essential knowledge enabling the successful design of today's new energy efficient HVAC systems. The author introduces important concepts such as Knowledge Categorization, Performance Based Design Standards, and Quantification of Uncertainty in Energy Modeling for Buildings. Pivotal topics that all HVAC and architectural engineers must master in order to navigate the green building renaissance are given focused attention, including the role of renewables, air quality, automatic controls, and thermal comfort. Relevant ASHRAE standards, as well as sustainability s

  13. HVAC (heating, ventilation, air conditioning) literature in Japan: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Hane, G.J.

    1988-02-01

    Japanese businessmen in the heating, ventilation, air conditioning, and refrigeration (HVACandR) industry consider the monitoring of technical and market developments in the United States to be a normal part of their business. In contrast, efforts by US businessmen to monitor Japanese HVAC and R developments are poorly developed. To begin to redress this imbalance, this report establishes the groundwork for a more effective system for use in monitoring Japanese HVAC and R literature. Discussions of a review of the principal HVAC and R publications in Japan and descriptions of the type of information contained in each of those publications are included in this report. Since the Japanese HVAC and R literature is abundant, this report also provides practical suggestions on how a researcher or research manager can limit the monitoring effort to the publications and type of information that would most likely be of greatest value.

  14. The consistency service of the ATLAS Distributed Data Management system

    CERN Document Server

    Serfon, C; The ATLAS collaboration

    2011-01-01

    With the continuously increasing volume of data produced by ATLAS and stored on the WLCG sites, the probability of data corruption or data losses, due to software and hardware failures is increasing. In order to ensure the consistency of all data produced by ATLAS a Consistency Service has been developed as part of the DQ2 Distributed Data Management system. This service is fed by the different ATLAS tools, i.e. the analysis tools, production tools, DQ2 site services or by site administrators that report corrupted or lost files. It automatically corrects the errors reported and informs the users in case of irrecoverable file loss.

  15. The Consistency Service of the ATLAS Distributed Data Management system

    CERN Document Server

    Serfon, C; The ATLAS collaboration

    2010-01-01

    With the continuously increasing volume of data produced by ATLAS and stored on the WLCG sites, the probability of data corruption or data losses, due to software and hardware failure is increasing. In order to ensure the consistency of all data produced by ATLAS a Consistency Service has been developed as part of the DQ2 Distributed Data Management system. This service is fed by the different ATLAS tools, i.e. the analysis tools, production tools, DQ2 site services or by site administrators that report corrupted or lost files. It automatically correct the errors reported and informs the users in case of irrecoverable file loss.

  16. The internal consistency of the North Sea carbonate system

    Science.gov (United States)

    Salt, Lesley A.; Thomas, Helmuth; Bozec, Yann; Borges, Alberto V.; de Baar, Hein J. W.

    2016-05-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three parameters (AT, DIC, pCO2) measured on four additional re-occupations, covering all four seasons, allowing an assessment of the internal consistency of the carbonate system. For most of the year, there is a similar level of internal consistency, with AT being calculated to within ± 6 μmol kg- 1 using DIC and pH, DIC to ± 6 μmol kg- 1 using AT and pH, pH to ± 0.008 using AT and pCO2, and pCO2 to ± 8 μatm using DIC and pH, with the dissociation constants of Millero et al. (2006). In spring, however, we observe a significant decline in the ability to accurately calculate the carbonate system. Lower consistency is observed with an increasing fraction of Baltic Sea water, caused by the high contribution of organic alkalinity in this water mass, not accounted for in the carbonate system calculations. Attempts to improve the internal consistency by accounting for the unconventional salinity-borate relationships in freshwater and the Baltic Sea, and through application of the new North Atlantic salinity-boron relationship (Lee et al., 2010), resulted in no significant difference in the internal consistency.

  17. Enhanced data consistency of a portable gait measurement system

    Science.gov (United States)

    Lin, Hsien-I.; Chiang, Y. P.

    2013-11-01

    A gait measurement system is a useful tool for rehabilitation applications. Such a system is used to conduct gait experiments in large workplaces such as laboratories where gait measurement equipment can be permanently installed. However, a gait measurement system should be portable if it is to be used in clinics or community centers for aged people. In a portable gait measurement system, the workspace is limited and landmarks on a subject may not be visible to the cameras during experiments. Thus, we propose a virtual-marker function to obtain positions of unseen landmarks for maintaining data consistency. This work develops a portable clinical gait measurement system consisting of lightweight motion capture devices, force plates, and a walkway assembled from plywood boards. We evaluated the portable clinic gait system with 11 normal subjects in three consecutive days in a limited experimental space. Results of gait analysis based on the verification of within-day and between-day coefficients of multiple correlations show that the proposed portable gait system is reliable.

  18. Testing of blowers and HVAC systems. Guide for energy optimization regarding ambient air ventilation systems. Pruefungen von Ventilatoren und Raumlufttechnischen Geraeten. Wegweiser zur Energieoptimierung bei RLT-Geraeten

    Energy Technology Data Exchange (ETDEWEB)

    Breit, O.

    1992-09-01

    Through a continuously increasing environmental consciousness and the increase of energy cost to be expected in the next years, ambient air ventilation systems with an optimized energy consumption are increasingly applied. For the determination of the energy consumption, special test rigs for the capacity are necessary. They consist of two climatic chambers arranged side by side, two measured sections and two speed controlled supporting fans. The tests carried out on the capacity and function of ambient air ventilation systems showed that the power consumption and thus, the energy consumption can be considerably reduced through constructional changes and an exact design of single components based on measured results. (BWI).

  19. Impact of HVAC control improvements on supermarket humidity levels

    Energy Technology Data Exchange (ETDEWEB)

    Khattar, M.; Henderson, H.I. Jr.

    1999-07-01

    This paper presents field-monitored data from two supermarkets where the impact of implementing minor HVAC control improvements was evaluated. The control improvements were intended to increase the dehumidification capacity of the HVAC system and lower space humidity levels. Direct digital control (DDC) was installed at each store to monitor system performance and implement the control improvements. At the first test store, a 33,400 ft{sup 2} (3,104 m{sup 2}) supermarket near Minneapolis, a conventional 50 ton (176 kW) split system conditioned the sales area. At the second store, a 50,000 ft{sup 2} (4,647 m{sup 2}{minus}) supermarket near Indianapolis, three rooftop units (RTUs) with a total capacity of 98 tons (344 kW) conditioned the store. The results from both supermarkets confirm the impact that supply airflow and part-load control of evaporator coil temperatures can have on dehumidification performance. Seemingly minor control adjustments can often have a big impact on the performance of supermarket HVAC systems. Even enhanced dehumidification technologies, such as heat pipe-assisted evaporator coils, can benefit from minor system tuning.

  20. Modeling and Simulation of HVAC Faulty Operations and Performance Degradation due to Maintenance Issues

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liping; Hong, Tianzhen

    2013-01-01

    Almost half of the total energy used in the U.S. buildings is consumed by heating, ventilation and air conditionings (HVAC) according to EIA statistics. Among various driving factors to energy performance of building, operations and maintenance play a significant role. Many researches have been done to look at design efficiencies and operational controls for improving energy performance of buildings, but very few study the impacts of HVAC systems maintenance. Different practices of HVAC system maintenance can result in substantial differences in building energy use. If a piece of HVAC equipment is not well maintained, its performance will degrade. If sensors used for control purpose are not calibrated, not only building energy usage could be dramatically increased, but also mechanical systems may not be able to satisfy indoor thermal comfort. Properly maintained HVAC systems can operate efficiently, improve occupant comfort, and prolong equipment service life. In the paper, maintenance practices for HVAC systems are presented based on literature reviews and discussions with HVAC engineers, building operators, facility managers, and commissioning agents. We categorize the maintenance practices into three levels depending on the maintenance effort and coverage: 1) proactive, performance-monitored maintenance; 2) preventive, scheduled maintenance; and 3) reactive, unplanned or no maintenance. A sampled list of maintenance issues, including cooling tower fouling, boiler/chiller fouling, refrigerant over or under charge, temperature sensor offset, outdoor air damper leakage, outdoor air screen blockage, outdoor air damper stuck at fully open position, and dirty filters are investigated in this study using field survey data and detailed simulation models. The energy impacts of both individual maintenance issue and combined scenarios for an office building with central VAV systems and central plant were evaluated by EnergyPlus simulations using three approaches: 1) direct

  1. HVAC-DYNAMIC: a training simulator for dynamic analysis of HVAC plants

    Directory of Open Access Journals (Sweden)

    Morten Heintz

    1989-07-01

    Full Text Available HVAC-DYNAMIC is a software tool for the dynamic simulation of Heating, Ventilation and Air Conditioning (HVAC plants. The program is designed to be used by HVAC engineers during design or troubleshooting of plants and by plant operators in their training. The program is based on a set of the most-used HVAC plant configurations and requires only a minimum of knowledge in numeric methods and programming. A brief presentation of the program structure and examples showing some of the application of the program are given.

  2. ENERGY STAR Certified Light Commercial HVAC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.0 ENERGY STAR Program Requirements for Light Commercial HVAC that are effective as of...

  3. HVAC design manual for hospitals and clinics

    National Research Council Canada - National Science Library

    2013-01-01

    "Provides in-depth design recommendations and proven, cost effective, and reliable solutions for health care HVAC design that provide low maintenance cost and high reliability based on best practices...

  4. ANFIS -Based Navigation for HVAC Service Robot with Image Processing

    Science.gov (United States)

    Salleh, Mohd Zoolfadli Md; Rashid, Nahrul Khair Alang Md; Mohd Mustafah, Yasir

    2013-12-01

    In this paper, we present an ongoing work on the autonomous navigation of a mobile service robot for Heat, Ventilation and Air Condition (HVAC) ducting. CCD camera mounted on the front-end of our robot is used to analyze the ducts openings (blob analysis) in order to differentiate them from other landmarks (blower fan, air outlets and etc). Distance between the robot and duct openings is measured using ultrasonic sensor. Controller chosen is ANFIS where its architecture accepts three inputs; recognition of duct openings, robot positions and distance while the outputs is maneuver direction (left or right).45 membership functions are created from which produces 46 training epochs. In order to demonstrate the functionality of the system, a working prototype is developed and tested inside HVAC ducting in ROBOCON Lab, IIUM.

  5. On-site study of HCFC-22 substitution for HFC non-azeotropic blends (R417A, R422D) on a water chiller of a centralized HVAC system

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, E.; Larumbe, J.A. [Polytechnic University of Valencia, Dep. of Applied Thermodynamics, Camino de Vera 14, E-46022 Valencia (Spain); Cabello, R.; Sanchez, D.; Llopis, R. [Jaume I University, Dep. of Mechanical Engineering and Construction, Campus de Riu Sec s/n, E-12071 Castellon (Spain)

    2010-09-15

    The European Regulation no 2037/2000 has banned manufacturing HCFC refrigerants from January 1st 2010, although its use is allowed up to 2015 if the fluids come from a recycling process. This situation creates the need for developing new working fluids to replace the HCFC in the refrigeration plants now in operation. Among all the HCFCs the R22 is the most widely used in a wide range of applications, especially in air conditioning. This work presents an on-site experimental study of the R22 replacement by two possible substitutes, the HFC-417A and the HFC-422D, in a water chiller in which the energy performance was evaluated. This chiller is part of the centralized HVAC system of a lecture room building at the Jaume I University of Castellon, Spain. This communication compares and analyses main operation parameters of the chiller when operating with each refrigerant in real conditions. (author)

  6. Applications of self-consistent field theory in polymer systems

    Institute of Scientific and Technical Information of China (English)

    YANG; Yuliang; QIU; Feng; TANG; Ping; ZHANG; Hongdong

    2006-01-01

    The self-consistent field theory (SCFT) based upon coarse-grained model is especially suitable for investigating thermodynamic equilibrium morphology and the phase diagram of inhomogeneous polymer systems subjected to phase separation. The advantage of this model is that the details of the chain such as the architecture of the chain and the sequence of blocks can be considered. We present here an overview of SCFT approach and its applications in polymeric systems. In particular, we wish to focus on our group's achievements in applications of SCFT in such fields: simulation of microphase separation morphologies of multiblock copolymers with a complex molecular architecture, interactions between brush-coated sheets in a polymer matrix, mixtures of flexible polymers and small molecular liquid crystals at the interface, shapes of polymer-chain-anchored fluid vesicles, self-assembled morphologies of block copolymers in dilute solution, and so on. Finally, the further developments as well as the perspective applications of SCFT are discussed.

  7. A Consistent Design Methodology for Wireless Embedded Systems

    Directory of Open Access Journals (Sweden)

    Sauzon G

    2005-01-01

    Full Text Available Complexity demand of modern communication systems, particularly in the wireless domain, grows at an astounding rate, a rate so high that the available complexity and even worse the design productivity required to convert algorithms into silicon are left far behind. This effect is commonly referred to as the design productivity crisis or simply the design gap. Since the design gap is predicted to widen every year, it is of utmost importance to look closer at the design flow of such communication systems in order to find improvements. While various ideas for speeding up designs have been proposed, very few have found their path into existing EDA products. This paper presents requirements for such tools and shows how an open design environment offers a solution to integrate existing EDA tools, allowing for a consistent design flow, considerably speeding up design times.

  8. Thermodynamically consistent Bayesian analysis of closed biochemical reaction systems

    Directory of Open Access Journals (Sweden)

    Goutsias John

    2010-11-01

    Full Text Available Abstract Background Estimating the rate constants of a biochemical reaction system with known stoichiometry from noisy time series measurements of molecular concentrations is an important step for building predictive models of cellular function. Inference techniques currently available in the literature may produce rate constant values that defy necessary constraints imposed by the fundamental laws of thermodynamics. As a result, these techniques may lead to biochemical reaction systems whose concentration dynamics could not possibly occur in nature. Therefore, development of a thermodynamically consistent approach for estimating the rate constants of a biochemical reaction system is highly desirable. Results We introduce a Bayesian analysis approach for computing thermodynamically consistent estimates of the rate constants of a closed biochemical reaction system with known stoichiometry given experimental data. Our method employs an appropriately designed prior probability density function that effectively integrates fundamental biophysical and thermodynamic knowledge into the inference problem. Moreover, it takes into account experimental strategies for collecting informative observations of molecular concentrations through perturbations. The proposed method employs a maximization-expectation-maximization algorithm that provides thermodynamically feasible estimates of the rate constant values and computes appropriate measures of estimation accuracy. We demonstrate various aspects of the proposed method on synthetic data obtained by simulating a subset of a well-known model of the EGF/ERK signaling pathway, and examine its robustness under conditions that violate key assumptions. Software, coded in MATLAB®, which implements all Bayesian analysis techniques discussed in this paper, is available free of charge at http://www.cis.jhu.edu/~goutsias/CSS%20lab/software.html. Conclusions Our approach provides an attractive statistical methodology for

  9. Improving risk assessment by defining consistent and reliable system scenarios

    Directory of Open Access Journals (Sweden)

    B. Mazzorana

    2009-02-01

    Full Text Available During the entire procedure of risk assessment for hydrologic hazards, the selection of consistent and reliable scenarios, constructed in a strictly systematic way, is fundamental for the quality and reproducibility of the results. However, subjective assumptions on relevant impact variables such as sediment transport intensity on the system loading side and weak point response mechanisms repeatedly cause biases in the results, and consequently affect transparency and required quality standards. Furthermore, the system response of mitigation measures to extreme event loadings represents another key variable in hazard assessment, as well as the integral risk management including intervention planning. Formative Scenario Analysis, as a supplement to conventional risk assessment methods, is a technique to construct well-defined sets of assumptions to gain insight into a specific case and the potential system behaviour. By two case studies, carried out (1 to analyse sediment transport dynamics in a torrent section equipped with control measures, and (2 to identify hazards induced by woody debris transport at hydraulic weak points, the applicability of the Formative Scenario Analysis technique is presented. It is argued that during scenario planning in general and with respect to integral risk management in particular, Formative Scenario Analysis allows for the development of reliable and reproducible scenarios in order to design more specifically an application framework for the sustainable assessment of natural hazards impact. The overall aim is to optimise the hazard mapping and zoning procedure by methodologically integrating quantitative and qualitative knowledge.

  10. Consistent Probabilistic Description of the Neutral Kaon System

    CERN Document Server

    Bernabeu, J; Villanueva-Perez, P

    2013-01-01

    The neutral Kaon system has both CP violation in the mass matrix and a non-vanishing lifetime difference in the width matrix. This leads to an effective Hamiltonian which is not a normal operator, with incompatible (non-commuting) masses and widths. In the Weisskopf-Wigner Approach (WWA), by diagonalizing the entire Hamiltonian, the unphysical non-orthogonal "stationary" states $K_{L,S}$ are obtained. These states have complex eigenvalues whose real (imaginary) part does not coincide with the eigenvalues of the mass (width) matrix. In this work we describe the system as an open Lindblad-type quantum mechanical system due to Kaon decays. This approach, in terms of density matrices for initial and final states, provides a consistent probabilistic description, avoiding the standard problems because the width matrix becomes a composite operator not included in the Hamiltonian. We consider the dominant-decay channel to two pions, so that one of the Kaon states with definite lifetime becomes stable. This new approa...

  11. Consistent Steering System using SCTP for Bluetooth Scatternet Sensor Network

    Science.gov (United States)

    Dhaya, R.; Sadasivam, V.; Kanthavel, R.

    2012-12-01

    Wireless communication is the best way to convey information from source to destination with flexibility and mobility and Bluetooth is the wireless technology suitable for short distance. On the other hand a wireless sensor network (WSN) consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants. Using Bluetooth piconet wireless technique in sensor nodes creates limitation in network depth and placement. The introduction of Scatternet solves the network restrictions with lack of reliability in data transmission. When the depth of the network increases, it results in more difficulties in routing. No authors so far focused on the reliability factors of Scatternet sensor network's routing. This paper illustrates the proposed system architecture and routing mechanism to increase the reliability. The another objective is to use reliable transport protocol that uses the multi-homing concept and supports multiple streams to prevent head-of-line blocking. The results show that the Scatternet sensor network has lower packet loss even in the congestive environment than the existing system suitable for all surveillance applications.

  12. VARIABLE SPEED INTEGRATED INTELLIGENT HVAC BLOWER

    Energy Technology Data Exchange (ETDEWEB)

    Shixiao Wang; Herman Wiegman; Wilson Wu; John Down; Luana Iorio; Asha Devarajan; Jing Wang; Ralph Carl; Charlie Stephens; Jeannine Jones; Paul Szczesny

    2001-11-14

    This comprehensive topical report discusses the key findings in the development of a intelligent integrated blower for HVAC applications. The benefits of rearward inclined blades over that of traditional forward inclined blades is well documented and a prototype blower design is presented. A comparison of the proposed blower to that of three typical units from the industry is presented. The design of the blower housing is also addressed and the impact of size limitations on static efficiency is discussed. Issues of air flow controllability in the rearward inclined blower is addressed and a solution to this problem is proposed. Several motor design options are discussed including inside-out radial flux designs and novel axial flux designs, all are focused on the various blower needs. The control of the motor-blower and airflow through the use of a high density inverter stage and modern digital signal processor is presented. The key technical challenges of the approach are discussed. The use of the motor as a sensor in the larger heating/ventilating system is also discussed. Diagnostic results for both the motor itself and the blower system are presented.

  13. State of the Art of HVAC Technology in Europe and America

    DEFF Research Database (Denmark)

    Olesen, Bjarne W.; Kazanci, Ongun Berk

    2015-01-01

    mechanisms and media to emit and remove heat or moisture from indoor spaces (e.g. hydronic radiant heating and cooling systems, fan-coil units, and active beams). The main differences between HVAC systems in Europe, North America and other parts of the world are often the indoor terminal units. Type...... for increasing the energy efficiency of HVAC (heating, ventilation and air-conditioning) systems and for increasing the amount of renewable energy used. Especially these types of systems are getting increasing attention in Europe and North-America. In the present study, operation characteristics, possibilities...

  14. Self-consistent theory for systems with mesoscopic fluctuations

    Science.gov (United States)

    Ciach, A.; Góźdź, W. T.

    2016-10-01

    We have developed a theory for inhomogeneous systems that allows for the incorporation of the effects of mesoscopic fluctuations. A hierarchy of equations relating the correlation and direct correlation functions for the local excess φ ≤ft(\\mathbf{r}\\right) of the volume fraction of particles ζ has been obtained, and an approximation leading to a closed set of equations for the two-point functions has been introduced for the disordered inhomogeneous phase. We have numerically solved the self-consistent equations for one-dimensional (1D) and three-dimensional (3D) models with short-range attraction and long-range repulsion. Predictions for all of the qualitative properties of the 1D model agree with the exact results, but only semi-quantitative agreement is obtained in the simplest version of the theory. The effects of fluctuations in the two 3D models considered are significantly different, despite the very similar properties of these models in the mean-field approximation. In both cases we obtain the sequence of large-small-large compressibility for increasing ζ. The very small compressibility is accompanied by the oscillatory decay of correlations with correlation lengths that are orders of magnitude larger than the size of particles. In one of the two models considered, the small compressibility becomes very small and the large compressibility becomes very large with decreasing temperature, and eventually van der Waals loops appear. Further studies are necessary in order to determine the nature of the strongly inhomogeneous phase present for intermediate volume fractions in 3D.

  15. ENVIRONMENTAL AND FINANCIAL INDICATORS OF THE RETROFIT OF HVAC SYSTEM OF A BANK BRANCH = INDICADORES AMBIENTAIS E FINANCEIROS DO RETROFIT DO SISTEMA DE AR CONDICIONADO DE UMA AGÊNCIA BANCÁRIA

    Directory of Open Access Journals (Sweden)

    Marcio Ferreira de Lima

    2016-09-01

    Full Text Available The purpose of this study was to analyze some environmental and financial indicators of the retrofit installation in the heating, ventilating and air conditioning system (HVAC of a bank branch. The building is located in downtown Florianópolis, SC, Brazil. The replacement of the system occurred in 2012. The method analyzed the results of the year 2013 compared with previous years in the matters of: energy efficiency, mitigation of greenhouse gases (GHG and financial investment analysis. The results were: 24.18% electricity savings and 51.31 tCO2eq mitigation of GHG emissions that are equivalent to planting 536 trees. The financial analysis showed that the retrofit is advantageous with benefit-cost ratio 0.60 and 14.85 years payback period. It was concluded that one year after the implementation of the retrofit was achieved the expected objective, which was to replace the old HVAC system with a new one more energy efficient, reducing energy consumption and the resulting reduction of the environmental impact. = O objetivo deste artigo é analisar alguns indicadores ambientais e financeiros da obra de retrofit do sistema de ar condicionado de uma agência bancária. O edifício está localizado no centro da cidade de Florianópolis, SC. A substituição do sistema ocorreu no ano de 2012. O método analisou os resultados do ano de 2013 em comparação com os anos anteriores quanto aos aspectos de: eficiência energética, mitigação de emissões de gases de efeito estufa (GEE e análise financeira do investimento. Os resultados foram: economia de 24,18% de energia elétrica e mitigação de 51,31 tCO2eq das emissões de GEE que são equivalentes ao plantio de 536 árvores. A análise financeira demonstrou que o retrofit é vantajoso com índice benefício/custo de 0,60 e payback de 14,85 anos. Conclui-se que um ano após a execução da obra de retrofit foi atingido o objetivo esperado, que era substituir o sistema de ar condicionado antigo por um

  16. Implementation of new concepts for space HVAC systems in domestic buildings in consideration of cost, consumption and user comfort. Final report; Umsetzung neuer Konzepte der technischen Gebaeudeausruestung im Wohnungsbau unter Beruecksichtigung von Kosten, Verbraeuchen und Nutzerkomfort. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, F.; Sucic, D.; Wendler, M.

    1998-03-01

    The goal of this project was the development of a set of tools for the selection of optimal concepts for HVAC-systems in housing buildings. Several factors are considered. They include technical feasibility, costs for investment, maintenance and operation, energy concumption, environmental impacts and user comfort. It is intended with the help of these tools to identify the most important factors which influence energy consumption and to suggest simple and cost effective measures to reduce energy consumption. Measures include improvements of the envelope, changes in the HVAC-system and its operation according to the needs to the inhabitants of the building. This report describes these components of this tool set which were developed in the frame of the project WohnKomfort. It lists data and rules chosen. In addition we report experiences which we gained with an prototypical implementation. This implementation allows load calculations for more than 60.000 different buildings applying EN 802 (only one zone model) as calculation method. It also supports selection of heating systems for such buildings by offering an evaluation according to user specified criteria including cost, environment and comfort. (orig./MM) [Deutsch] Ziel des Vorhabens war die Entwicklung eines Instrumentariums zur Auswahl optimaler Konzepte fuer technische Anlagen in Wohngebaeuden unter Beruecksichtigung der Faktoren technische Machbarkeit, Erstellungs-, Betriebskosten, Energieverbrauch, Umweltbelastung und Nutzerkomfort. Mit Hilfe dieses Instrumentariums soll es moeglich werden, die Haupteinflussfaktoren fuer den Energieverbrauch anzugeben und Vorschlaege fuer einfache und kostenguenstige Massnahmen zu seiner Reduzierung auf der Seite des Gebaeudes (bauliche Massnahmen) und der Anlage (technische Massnahmen, Nutzerverhalten) anzugeben. In diesem Bericht beschreiben wir die im Vorhaben entwickelten Komponenten des Instrumentariums, die zugrundeliegenden Daten und Regeln sowie Erfahrungen, die

  17. HVAC--the importance of clean intake section and dry air filter in cold climate.

    Science.gov (United States)

    Hanssen, S O

    2004-01-01

    HVAC systems, if properly designed, installed, operated and maintained, will improve thermal conditions and air quality indoors. However, the success strongly depends on the design of the system and the quality of the components we use in our HVAC installations. Regrettably, several investigations have revealed that many HVAC installations have a lot of operational and maintenance problems, especially related to moisture, rain and snow entrainment. In short, it seems that too little attention is placed on the design of the intake section, despite the fact that there exists a large number of national and international guidelines and recommendations. This is a serious problem because the air intake is the initial component of the ventilation plant and as such the first line of defense against debris and other outdoor air pollutants. Unfortunately, the design is often an argued compromise between the architect, the civil engineer and the HVAC engineer. In the future, the technical, hygienic and microbiological feature of air intakes must be better ensured in order to avoid the air intake becoming a risk component as regards contamination and indoor air quality. Further, it seems that the magnitude of the problem is not well known, or recognized, by the building designers, engineers and professionals involved in the construction and operation of buildings. This fact needs to be addressed more seriously, because obviously there is a big difference between the idealistic architectonic design, engineering intentions and the real life situation. Several practical recommendations for design and operation of HVAC systems are presented. Following the recommendations will result in less pollution from the HVAC-system and increased indoor environmental quality.

  18. Residential and Light Commercial HVAC. Teacher Edition.

    Science.gov (United States)

    Stephenson, David; Fulkerson, Dan, Ed.

    This curriculum guide contains 18 units of instruction for a competency-based course in residential and light commercial heating, ventilating, and air conditioning (HVAC). Introductory materials include a competency profile and an instructional/task analysis that correlates job training with related information for this course. Each instructional…

  19. Understanding and Improving the Performance Consistency of Distributed Computing Systems

    NARCIS (Netherlands)

    Yigitbasi, M.N.

    2012-01-01

    With the increasing adoption of distributed systems in both academia and industry, and with the increasing computational and storage requirements of distributed applications, users inevitably demand more from these systems. Moreover, users also depend on these systems for latency and throughput sens

  20. Understanding and Improving the Performance Consistency of Distributed Computing Systems

    NARCIS (Netherlands)

    Yigitbasi, M.N.

    2012-01-01

    With the increasing adoption of distributed systems in both academia and industry, and with the increasing computational and storage requirements of distributed applications, users inevitably demand more from these systems. Moreover, users also depend on these systems for latency and throughput sens

  1. HVAC optimization as facility requirements change with corporate restructuring

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, R.R.; Sankey, M.S.

    1997-06-01

    The hyper-competitive, dynamic 1990`s forced many corporations to {open_quotes}Right-Size,{close_quotes} relocating resources and equipment -- even consolidating. These changes led to utility reduction if HVAC optimization was thoroughly addressed, and energy conservation opportunities were identified and properly designed. This is true particularly when the facility`s heating and cooling systems are matched to correspond with the load changes attributed to the reduction of staff and computers. Computers have been downsized and processing power per unit of energy input increased, thus, the need for large mainframe computer centers, and their associated high intensity energy usage, have been decreased or eliminated. Cooling, therefore, also has been reduced.

  2. HVAC in sustainable office buildings a bridge between owners and engineers

    CERN Document Server

    Hovorka, Frank; Kurnitski, Jarek; Litiu, Andrei

    2012-01-01

    This guidebook aims to build a bridge between the real estate community and the engineering community. It explains the challenges of property valuation based on real data and how the sustainability and HVAC-technology can have an impact on value. It also gathers the latest HVAC- and other technologies used in sustainable buildings and gives some real case study examples. But maybe the most important part in terms of improved communication between the owners and engineers is the list of questions to be asked during the life time of a building. It is impossible to give all the right answers in this guidebook, but we will raise some pertinent questions. As climates and cultures are different, as well as existing building types and energy production, the same solutions do not solve problems universally. This guidebook is aimed for the owners and architects as well as engineers. It doesn’t require deep technical knowhow of HVAC-systems or real estate valuation.

  3. Energy Renovations: Volume 14: HVAC - A Guide for Contractors to Share with Homeowners

    Energy Technology Data Exchange (ETDEWEB)

    Gilbride, Theresa L.; Baechler, Michael C.; Hefty, Marye G.; Hand, James R.; Love, Pat M.

    2011-08-29

    This report was prepared by PNNL for DOE's Building America program and is intended as a guide that energy performance contractors can share with homeowners to describe various energy-efficient options for heating, cooling, and ventilating existing homes. The report provides descriptions of many common and not-so-common HVAC systems, including their advantages and disadvantages, efficiency ranges and characteristics of high-performance models, typical costs, and climate considerations. The report also provides decision trees and tables of useful information for homeowners who are making decisions about adding, replacing, or upgrading existing HVAC equipment in their homes. Information regarding home energy performance assessments (audits) and combustion safety issues when replacing HVAC equipment are also provided.

  4. Energy Savings Potential and RD&D Opportunities for Non-Vapor-Compression HVAC Technologies

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-03-01

    While vapor-compression technologies have served heating, ventilation, and air-conditioning (HVAC) needs very effectively, and have been the dominant HVAC technology for close to 100 years, the conventional refrigerants used in vapor-compression equipment contribute to global climate change when released to the atmosphere. This Building Technologies Office report: --Identifies alternatives to vapor-compression technology in residential and commercial HVAC applications --Characterizes these technologies based on their technical energy savings potential, development status, non-energy benefits, and other factors affecting end-user acceptance and their ability to compete with conventional vapor-compression systems --Makes specific research, development, and deployment (RD&D) recommendations to support further development of these technologies, should DOE choose to support non-vapor-compression technology further.

  5. An Evaluation of Information Consistency in Grid Information Systems

    CERN Document Server

    Field, Laurence

    2016-01-01

    A Grid information system resolves queries that may need to consider all information sources (Grid services), which are widely distributed geographically, in order to enable efficient Grid functions that may utilise multiple cooperating services. Fundamentally this can be achieved by either moving the query to the data (query shipping) or moving the data to the query (data shipping). Existing Grid information system implementations have adopted one of the two approaches. This paper explores the two approaches in further detail by evaluating them to the best possible extent with respect to Grid information system benchmarking metrics. A Grid information system that follows the data shipping approach based on the replication of information that aims to improve the currency for highly-mutable information is presented. An implementation of this, based on an Enterprise Messaging System, is evaluated using the benchmarking method and the consequence of the results for the design of Grid information systems is discu...

  6. DISAIN SISTEM KENDALI MESIN AIR LEAK TEST MENGGUNAKAN SISTEM KENDALI PLC OMRON CJ2M DI HVAC (HEATING, VENTILATING, AND AIR CONDITIONING LINE 6

    Directory of Open Access Journals (Sweden)

    Syahril Ardi

    2015-03-01

    Full Text Available Pada proses produksi pembuatan komponen HVAC (Heating, Ventilating, and Air Conditioning dari perusahaan manufaktur di Indonesia, memerlukan proses pengecekan kebocoran pada bagian HVAC. Proses pengecekan ini dilakukan untuk memastikan tidak ada komponen HVAC yang bocor sebelum dikirim ke pihak pelanggan. Penelitian ini dilakukan untuk membuat system dan alat air leak test. Mesin air leak test ini menggunakan prinsip kerja differential pressure air leak test, yaitu metode yang membandingkan antara tekanan udara yang diberikan ke produk dan master produk. Pada penelitian ini, kami membuat disain mesin air leak test menggunakan sistem kendali berupa air leak tester, PLC, dan HMI. Berdasarkan kondisi dengan kapasitas produksi yang meningkat karena bertambahnya permintaan dari customer, dapat ditanggulangi dengan adanya share loading produksi dari HVAC line 4 ke line baru, yaitu HVAC line 6. Hasil yang didapat dari pengujian deteksi kebocoran produk,didapat nilai parameter kebocoran produk sebesar 2.23 ml/min.

  7. Consistency of System Identification by Global Total Least Squares

    NARCIS (Netherlands)

    C. Heij (Christiaan); W. Scherrer

    1996-01-01

    textabstractGlobal total least squares (GTLS) is a method for the identification of linear systems where no distinction between input and output variables is required. This method has been developed within the deterministic behavioural approach to systems. In this paper we analyse statistical proper

  8. BUILD: A Tool for Maintaining Consistency in Modular Systems.

    Science.gov (United States)

    1985-11-01

    set of definitions, BUILD can be extended to work with new programming environments and to perform new tasks. Keywords: High level languages; BUILD Computer program; C programming language; Systems engineering. (Author)

  9. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Introduction to Construction Series. Instructor Edition.

    Science.gov (United States)

    Associated General Contractors of America, Washington, DC.

    This module on introductory heating, ventilating, and air conditioning (HVAC) is one of a series of modules designed to teach basic skills necessary for entry-level employment in this field. The module contains four instructional units that cover the following topics: (1) HVAC materials; (2) HVAC tools; (3) HVAC layout; and (4) HVAC basic skills.…

  10. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Introduction to Construction Series. Instructor Edition.

    Science.gov (United States)

    Associated General Contractors of America, Washington, DC.

    This module on introductory heating, ventilating, and air conditioning (HVAC) is one of a series of modules designed to teach basic skills necessary for entry-level employment in this field. The module contains four instructional units that cover the following topics: (1) HVAC materials; (2) HVAC tools; (3) HVAC layout; and (4) HVAC basic skills.…

  11. Consistent Prediction of Properties of Systems with Lipids

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Sarup, Bent

    Equilibria between vapour, liquid and/or solid phases, pure component properties and also the mixture-phase properties are necessary for synthesis, design and analysis of different unit operations found in the production of edible oils, fats and biodiesel. A systematic numerical analysis...... is employed to determine the needs of phase equilibria and related properties in processes such as Deodorization, Dry Fractionation, Solvent Extraction and Biodiesel Production. Other important use for the data and analysis is in property model development for correct and consistent property prediction....... Lipids are found in almost all mixtures involving edible oils, fats and biodiesel. They are also being extracted for use in the pharma-industry. A database for pure components (lipids) present in these processes and mixtures properties has been developed and made available for different applications...

  12. The consistency service of the ATLAS distributed data management system

    Energy Technology Data Exchange (ETDEWEB)

    Serfon, Cedric; Calfayan, Philippe; Duckeck, Guenter; Ebke, Johannes; Elmsheuser, Johannes; Legger, Federica; Mitterer, Christoph; Schaile, Dorothee; Walker, Rodney [LMU, Munich (Germany)

    2011-07-01

    With the continuously increasing volume of data (More than 50 PB) produced by ATLAS and stored on the WLCG sites, the probability of data corruption or data losses (for instance due to hardware failure) is increasing. With the current size of the disks, a pool crash that cannot be recovered typically represents O(10000) files. It is therefore important to have an automated service to recover these file losses: this is the role of the Consistency Service. This service is used by various ATLAS tools (Analysis tools, Production tools, DQ2 Site Services..) or by site administrators that report corrupted or lost files. It automatically recovers lost files or corrects the errors reported and informs the users in case of irrecoverable file loss.

  13. Consistency of global total least squares in stochastic system identification

    NARCIS (Netherlands)

    C. Heij (Christiaan); W. Scherrer

    1995-01-01

    textabstractGlobal total least squares has been introduced as a method for the identification of deterministic system behaviours. We analyse this method within a stochastic framework, where the observed data are generated by a stationary stochastic process. Conditions are formulated so that the meth

  14. The internal consistency of the North Sea carbonate system

    NARCIS (Netherlands)

    Salt, S.; Thomas, H.; Bozec, Y.; Borges, A.V.; de Baar, H.J.W

    2016-01-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three paramete

  15. A consistent multi-user framework for assessing system performance

    CERN Document Server

    Reed, C M

    2010-01-01

    Agreeing suitability for purpose and procurement decisions depend on assessment of real or simulated performances of sonar systems against user requirements for particular scenarios. There may be multiple pertinent aspects of performance (e.g. detection, track estimation, identification/classification and cost) and multiple users (e.g. within picture compilation, threat assessment, resource allocation and intercept control tasks), each with different requirements. Further, the estimates of performances and the user requirements are likely to be uncertain. In such circumstances, how can we reliably assess and compare the effectiveness of candidate systems? This paper presents a general yet simple mathematical framework that achieves all of this. First, the general requirements of a satisfactory framework are outlined. Then, starting from a definition of a measure of effectiveness (MOE) based on set theory, the formulae for assessing performance in various applications are obtained. These include combined MOEs,...

  16. Reflection symmetries of Isolated Self-consistent Stellar Systems

    CERN Document Server

    An, J; Sanders, J L

    2016-01-01

    Isolated, steady-state galaxies correspond to equilibrium solutions of the Poisson--Vlasov system. We show that (i) all galaxies with a distribution function depending on energy alone must be spherically symmetric and (ii) all axisymmetric galaxies with a distribution function depending on energy and the angular momentum component parallel to the symmetry axis must also be reflection-symmetric about the plane $z=0$. The former result is Lichtenstein's Theorem, derived here by a method exploiting symmetries of solutions of elliptic partial differential equations, while the latter result is new. These results are subsumed into the Symmetry Theorem, which specifies how the symmetries of the distribution function in configuration or velocity space can control the planes of reflection symmetries of the ensuing stellar system.

  17. Reflection symmetries of Isolated Self-consistent Stellar Systems

    OpenAIRE

    An, J; Evans, N.W.; Sanders, J. L.

    2016-01-01

    Isolated, steady-state galaxies correspond to equilibrium solutions of the Poisson--Vlasov system. We show that (i) all galaxies with a distribution function depending on energy alone must be spherically symmetric and (ii) all axisymmetric galaxies with a distribution function depending on energy and the angular momentum component parallel to the symmetry axis must also be reflection-symmetric about the plane $z=0$. The former result is Lichtenstein's Theorem, derived here by a method exploit...

  18. IFC HVAC interface to EnergyPlus - A case of expanded interoperability for energy simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bazjanac, Vladimir; Maile, Tobias

    2004-03-29

    Tedious manual input of data that define a building, its systems and its expected pattern of use and operating schedules for building energy performance simulation has in the past diverted time and resources from productive simulation runs. In addition to its previously released IFCtoIDF utility that semiautomates the import of building geometry, the new IFC HVAC interface to EnergyPlus (released at the end of 2003) makes it possible to import and export most of the data that define HVAC equipment and systems in a building directly from and to other IFC compatible software tools. This reduces the manual input of other data needed for successful simulation with EnergyPlus to a minimum. The main purpose of this new interface is to enable import of HVAC equipment and systems definitions, generated by other IFC compatible software tools (such as HVAC systems design tools) and data bases, into EnergyPlus, and to write such definitions contained in EnergyPlus input files to the original IFC files from which building geometry was extracted for the particular EnergyPlus input. In addition, this interface sets an example for developers of other software tools how to import and/or export data other than building geometry from and/or into EnergyPlus. This paper describes the necessary simplifications and shortcuts incorporated in this interface, its operating environment, interface architecture, and the basic conditions and methodology for its use with EnergyPlus.

  19. Estimating the HVAC energy consumption of plug-in electric vehicles

    Science.gov (United States)

    Kambly, Kiran R.; Bradley, Thomas H.

    2014-08-01

    Plug in electric vehicles are vehicles that use energy from the electric grid to provide tractive and accessory power to the vehicle. Due to the limited specific energy of energy storage systems, the energy requirements of heating, ventilation, and air conditioning (HVAC) systems for cabin conditioning can significantly reduce their range between charges. Factors such as local ambient temperature, local solar radiation, local humidity, length of the trip and thermal soak have been identified as primary drivers of cabin conditioning loads and therefore of vehicle range. The objective of this paper is to develop a detailed systems-level approach to connect HVAC technologies and usage conditions to consumer-centric metrics of vehicle performance including energy consumption and range. This includes consideration of stochastic and transient inputs to the HVAC energy consumption model including local weather, solar loads, driving behavior, charging behavior, and regional passenger fleet population. The resulting engineering toolset is used to determine the summation of and geographical distribution of energy consumption by HVAC systems in electric vehicles, and to identify regions of US where the distributions of electric vehicle range are particularly sensitive to climate.

  20. The state of HVAC in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, M.M. [Air Quality Systems, Shawnee Mission, KS (United States)

    1997-07-01

    With the chartering of the Manual de Anda ASHRAE Chapter in Mexico City, the first chapter in Latin America, and with increasing cross-border trade and investment as a result of NAFTA, it`s important for US and Canadian engineers to understand the state of HVAC technology in Mexico. The goal of this article is to introduce the reader to some industry leaders in Mexico and to show their creative design and installation expertise by reviewing some recent projects.

  1. Electrostatic MEMS vibration energy harvester for HVAC applications

    Science.gov (United States)

    Oxaal, J.; Hella, M.; Borca-Tasciuc, D.-A.

    2015-12-01

    This paper reports on an electrostatic MEMS vibration energy harvester with gapclosing interdigitated electrodes, designed for and tested on HVAC air ducts. The device is fabricated on SOI wafers using a custom microfabrication process. A dual-level physical stopper system is implemented in order to control the minimum gap between the electrodes and maximize the power output. It utilizes cantilever beams to absorb a portion of the impact energy as the electrodes approach the impact point, and a film of parylene with nanometer thickness deposited on the electrode sidewalls, which defines the absolute minimum gap and provides electrical insulation. The fabricated device was first tested on a vibration shaker to characterize its resonant behavior. The device exhibits spring hardening behavior due to impacts with the stoppers and spring softening behavior with increasing voltage bias. Testing was carried out on HVAC air duct vibrating with an RMS acceleration of 155 mgRMS and a primary frequency of 60 Hz with a PSD of 7.15·10-2 g2/Hz. The peak power measured is 12nW (0.6 nW RMS) with a PSD of 6.9·10-11 W/Hz at 240 Hz (four times of the primary frequency of 60 Hz), which is the highest output reported for similar vibration conditions and biasing voltages.

  2. Evaluating performance indices of a shopping centre and implementing HVAC control principles to minimize energy usage

    Energy Technology Data Exchange (ETDEWEB)

    Canbay, C.S. [Energy Engineering Programme, Izmir Institute of Technology, Izmir (Turkey); Hepbasli, A. [Faculty of Engineering, Mechanical Engineering Department, Ege University, Izmir (Turkey); Gokcen, G. [Faculty of Engineering, Mechanical Engineering Department, Izmir Institute of Technology, Izmir (Turkey)

    2004-07-01

    Heating, ventilation and air-conditioning (HVAC) systems in buildings must be integrated with an efficient control scheme to maintain comfort under any load conditions. Efficient HVAC control is often the most cost-effective option to improve the energy efficiency of a building. However, HVAC processes are non-linear, and characteristics change on a seasonal basis, so the effect of changing the control strategy is usually difficult to predict. The present study aims to reduce energy consumption by defining new HVAC control strategies and tuning control loops in a shopping centre. First, an energy audit was performed to investigate the potential for energy savings and to redefine the control scenarios, while a methodology for the shopping centre was developed. Performance indices were then calculated and compared with the yardsticks. Next, normalised performance indices were computed to reach out a better understanding of the building's efficiency. Finally, new strategies were implemented with the help of the existing building management system (BMS) and about 22% of energy saving was achieved. (author)

  3. The role of interactive control systems in obtaining internal consistency in the management control system package

    DEFF Research Database (Denmark)

    Toldbod, Thomas; Israelsen, Poul

    2014-01-01

    Companies rely on multiple Management Control Systems to obtain their short and long term objectives. When applying a multifaceted perspective on Management Control System the concept of internal consistency has been found to be important in obtaining goal congruency in the company. However...... of MCSs when analyzing internal consistency in the MCS package and how managers obtain internal consistency in the new MCS package when a MCS change occur. This study focuses specifically on changes to administrative controls, which are not internal consistent with the current cybernetic controls. As top......, to date we know little about how managers maintain internal consistency, when individual MCSs change and do not fit with the other MCSs. Based on a case study in a global Danish manufacturing company this study finds that it is necessary to distinguish between the design characteristics of MCS and use...

  4. A Novel Method for Saving Energy of HVAC Using Autonomous Variable Air Velocity Based On Thermal Comfort

    Science.gov (United States)

    Auttawaitkul, Yingrak; Therdyothin, Apichit; Monyakul, Veerapol

    The tower building categories used in the energy breakdown are Electric lighting, the heating, ventilating, and air conditioning (HVAC) auxiliary and Office equipment. The HVAC system has the greatest energy saving potential as it is the major energy consumer. It consumes approximately 64 percent of the total building energy. A good HVAC in buildings helps reduce energy use and maintain occupant comfort. To this end, there are many systems and equipment conditions to observe HVAC systems. This paper critically examines indoor climate control technologies to reduce the HVAC system energy. The autonomous variable air volume diffusers are interconnected to simulate the responses of the system. The constrained optimal control problem is formulated and solved for increased operative temperature. The experiment results show that by increasing the operative temperature from 25°C to 27°C, the electrical energy can be saved by 11.64 percent. The proposed method feeds back the output air to input boundary conditions of the same human thermal sensation even though the air velocity distributions in the sections are different from each other. The experiment results also show that the proposed method can maintain the PMV values in an interval of -0.5 to +0.5 at an acceptable air velocity range.

  5. Design principles of a nuclear and industrial HVAC of IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Pruneri, Giuseppe [IFMIF/EVEDA, Project Team, Rokkasho (Japan); Ibarra, A. [CIEMAT, Madrid (Spain); Heidinger, R. [F4E, Garching (Germany); Knaster, J. [IFMIF/EVEDA Project Team, Rokkasho (Japan); Sugimoto, M. [JAEA, Rokkasho (Japan)

    2016-02-15

    Highlights: • Parameter of Derivate air Contamination (DAC) allows to associate the type of air ventilation. • The construction and operation of IFMIF will be subjected to the regulations of the country in which it will be sited. • Structures, systems and components are assigned a particular safety important components (SIC, 1–2 and Non-SIC) clarification that is based on the consequences of their failure. • Reliability, Availability, Maintainability and Inspectability (RAMI) analysis has given a great contribution of the facility to optimize the configuration, particularly for the HVAC system. - Abstract: In 2013, the IFMIF, the International Fusion Material Irradiation Facility, presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase, framed by the Broader Approach Agreement between Japan and EURATOM, accomplished in 2013 its mandate to provide the engineering design of the plant on schedule [1]. The IFMIF aims to qualify and characterize materials that are capable of withstanding the intense neutron flux originated in D-T reactions of future fusion reactors due to a neutron flux with a broad peak at 14 MeV, which is able to provide >20 dpa/fpy on small specimens in this EVEDA phase. The successful operation of such a challenging plant demands a careful assessment of the Conventional Facilities (CF), which have adequate redundancies to allow for the target plant availability [2]. The present paper addresses the design proposed in the IFMIF Intermediate Engineering Design Report regarding the CF, particularly the IFMIF's Nuclear and Industrial HVAC design. A preliminary feasibility study, including the initial configuration, calculations and reliability/availability analysis, were performed. The nuclear HVAC design was developed progressively; first, by establishing a conceptual design, starting from the system functional description, followed by the identification of the corresponding interfacing systems and their

  6. Strategy Guideline. HVAC Equipment Sizing

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, Arlan [IBACOS, Inc., Pittsburgh, PA (United States)

    2012-02-01

    This guide describes the equipment selection of a split system air conditioner and furnace for an example house in Chicago, IL as well as a heat pump system for an example house in Orlando, FL. The required heating and cooling load information for the two example houses was developed in the Department of Energy Building America Strategy Guideline: Accurate Heating and Cooling Load Calculations.

  7. VARIABLE SPEED INTEGRATED INTELLIGENT HVAC BLOWER

    Energy Technology Data Exchange (ETDEWEB)

    Herman Wiegman; Charlie Stephens; Xiaoyue Liu; Ralph Carl; Sunny Zhuang; Paul Szczesny; Kamron Wright

    2003-09-23

    This comprehensive topical report discusses the key findings in the development of an advanced blower for HVAC applications. The benefits of rearward inclined blades over that of traditional forward inclined blades is well documented, and several prototype wheels are demonstrated in various housings. A comparison of retrofitted blowers to that of three typical units from the industry is presented. The design and modification of the blower housing is addressed and the impact of size limitations on static efficiency is discussed. The roadmap to rearward-inclined wheel technology insertion is presented and typical static efficiency gains are documented.

  8. State of the Art of HVAC Technology in Europe and America

    DEFF Research Database (Denmark)

    Olesen, Bjarne W.; Kazanci, Ongun Berk

    2015-01-01

    for increasing the energy efficiency of HVAC (heating, ventilation and air-conditioning) systems and for increasing the amount of renewable energy used. Especially these types of systems are getting increasing attention in Europe and North-America. In the present study, operation characteristics, possibilities...... mechanisms and media to emit and remove heat or moisture from indoor spaces (e.g. hydronic radiant heating and cooling systems, fan-coil units, and active beams). The main differences between HVAC systems in Europe, North America and other parts of the world are often the indoor terminal units. Type...... of energy sources and energy generators are very much similar. This paper will present state-of the art-off energy efficient systems that will provide a good indoor environmental quality at a decreased energy use. Low Temperature Heating and High Temperature Cooling systems are an important requirement...

  9. Exergy analysis of scroll compressors working with R22, R407C, and R417A as refrigerant for HVAC system

    Directory of Open Access Journals (Sweden)

    Kalaiselvam Sivakumar

    2009-01-01

    Full Text Available The rise in crisis of power enthralls the world economically and the options for conventional and non-conventional energy resources have been searched out. No system exists in this world with 100% efficiency due to several irreversibility's. If the output obtained from the system is maximum for a given input, maximum amount of energy can be saved globally. To understand the thermodynamic losses occurring in the system and to predict the available energy that can be tapped from the system, exergy plays a major role. Experimental study on exergy in a system can pave the way to understand the complete behavior of the system exergually. Conceptually exergy studies are based on simulation, to provide a new dimension to the concept of exergy experimental validation have been promoted. The analogy of exergy analysis of three refrigerants working in scroll compressors and their exergual features are explained in this paper. The refrigerants R22, R417A, and R407C and their thermo dynamical behavior, irreversibility were experimented in an air conditioning system with three scroll compressors, interaction between the system and the refrigerant in terms of pressure drop and heat transfer, friction has been implemented for the calculation of exergy. The entire system performance on the basis of refrigerant is validated in each part of the air conditioning system. The resultant coefficient of performance of R407C is 2.41% less than R22 in a R22 designed scroll compressor with minimal exergy losses. The second law efficiency of 50 to 55% obtained in R22 has fewer rules over R407C and R417A which has 48 to 52%. The diminutive deviation of results encourages R417A refrigerant to be used as a substitute for R22. Thus the exergual prediction of performance of refrigerant and second law efficiency can identify the use of eco-friendly refrigerant in scroll compressor.

  10. The Effects of Set-Points and Dead-Bands of the HVAC System on the Energy Consumption and Occupant Thermal Comfort

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk; Olesen, Bjarne W.

    2013-01-01

    with a ground heat exchanger, a ground coupled heat pump, embedded pipes in the floor and in the ceiling, a ventilation system (mechanical and natural), a domestic hot water tank and photovoltaic/thermal panels on the roof. Preliminary evaluations showed that for Madrid, change of indoor set-point in cooling......A building is a complex system where many components interact with each other therefore the control system plays a key role regarding the energy consumption and the occupant thermal comfort. This study is concerned with a detached, one-storey, single family, energy-plus house. It is equipped...... on the effects of the set-points and dead-bands of different components on the energy consumption together with the occupant thermal comfort. Evaluations are carried out with TRNSYS for Copenhagen and Madrid in order to compare climatic effects....

  11. Comparison between design and actual energy performance of a HVAC-ground coupled heat pump system in cooling and heating operation

    Energy Technology Data Exchange (ETDEWEB)

    Magraner, T.; Quilis, S. [Energesis Ingenieria S.L., Ciudad Politecnica de la Innovacion, Camino de Vera s/n, 46022 Valencia (Spain); Montero, A. [Instituto de Ingenieria Energetica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Urchueguia, J.F. [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2010-09-15

    This work compares the experimental results obtained for the energy performance study of a ground coupled heat pump system with the design values predicted by means of standard methodology. The system energy performance of a monitored ground coupled heat pump system is calculated using the instantaneous measurements of temperature, flow and power consumption and these values are compared with the numerical predictions. These predictions are performed with the TRNSYS software tool following standard procedures taking the experimental thermal loads as input values. The main result of this work is that simulation results solely based on nominal heat pump capacities and performances overestimate the measured overall energy performance by a percentage between 15% and 20%. A sensitivity analysis of the simulation results to changes in percentage of its input parameters showed that the heat pump nominal coefficient of performance is the parameter that mostly affects the energy performance predictions. This analysis supports the idea that the discrepancies between experimental results and simulation outputs for this ground coupled system are mainly due to heat pump performance degradation for being used at partial load. An estimation of the impact of this effect in energy performance predictions reduces the discrepancies to values around 5%. (author)

  12. Energy conservation in space HVAC systems. Improving specific blower performance with leaktight air ducts; Energieeinsparung in RLT-Anlagen. Verbesserung der spezifischen Ventilatorleistung mit dichteren Luftleitungen

    Energy Technology Data Exchange (ETDEWEB)

    Luft, J. [Lindab GmbH, Bargteheide (Germany)

    2005-07-01

    The 91 goals stated in the Energy Performance of Buildings Directive (EPBD) 2002/91 are implemented in German law by the Energy Conservation Ordinance and further standards and regulations. In the case of ventilation and air conditioning systems, DIN EN 13779 applies, in which a SFP (specific fan power) value is introduced. The contribution shows how leaktightness of air ducts will affect the SFP. (orig.)

  13. HVAC system design for Beijing Chao-Yang Hospital%北京朝阳医院暖通空调系统设计

    Institute of Scientific and Technical Information of China (English)

    赵文成

    2013-01-01

    Combined with state-of-the-art medical processes, allocates ventilation and air conditioning systems rationally and determines the positive and negative pressure of different rooms, the pressure gradient of clean rooms and the air flow direction, providing a reliable guarantee against cross-infection within the hospital. The project constructs the first domestic clean respiratory intensive care unit (RICU), the chemical poisoning emergency treatment center and the emergency center with A, B. C three zones admissions and treatment mechanism. Expounds their ventilation and air conditioning design.%结合先进的医疗流程,合理配置了通风空调系统,明确设计了房间的正负压、净化房间的压力梯度及气流流向,为防止医院内交叉感染提供了可靠的保证.该工程设计建成了国内首个净化的RICU和化学中毒紧急救治中心,急救中心分成A,B,C三区接诊及救治,详细介绍了这些场所的通风空调设计.

  14. Improving performance of HVAC systems to reduce exposure to aerosolized infectious agents in buildings; recommendations to reduce risks posed by biological attacks.

    Science.gov (United States)

    Hitchcock, Penny J; Mair, Michael; Inglesby, Thomas V; Gross, Jonathan; Henderson, D A; O'Toole, Tara; Ahern-Seronde, Joa; Bahnfleth, William P; Brennan, Terry; Burroughs, H E Barney; Davidson, Cliff; Delp, William; Ensor, David S; Gomory, Ralph; Olsiewski, Paula; Samet, Jonathan M; Smith, William M; Streifel, Andrew J; White, Ronald H; Woods, James E

    2006-01-01

    The prospect of biological attacks is a growing strategic threat. Covert aerosol attacks inside a building are of particular concern. In the summer of 2005, the Center for Biosecurity of the University of Pittsburgh Medical Center convened a Working Group to determine what steps could be taken to reduce the risk of exposure of building occupants after an aerosol release of a biological weapon. The Working Group was composed of subject matter experts in air filtration, building ventilation and pressurization, air conditioning and air distribution, biosecurity, building design and operation, building decontamination and restoration, economics, medicine, public health, and public policy. The group focused on functions of the heating, ventilation, and air conditioning systems in commercial or public buildings that could reduce the risk of exposure to deleterious aerosols following biological attacks. The Working Group's recommendations for building owners are based on the use of currently available, off-the-shelf technologies. These recommendations are modest in expense and could be implemented immediately. It is also the Working Group's judgment that the commitment and stewardship of a lead government agency is essential to secure the necessary financial and human resources and to plan and build a comprehensive, effective program to reduce exposure to aerosolized infectious agents in buildings.

  15. Self-Correcting HVAC Controls Project Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas; Cho, Heejin; Goddard, James K.; Dinh, Liem H.

    2010-01-04

    This document represents the final project report for the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls Project jointly funded by Bonneville Power Administration (BPA) and the U.S. Department of Energy (DOE) Building Technologies Program (BTP). The project, initiated in October 2008, focused on exploratory initial development of self-correcting controls for selected HVAC components in air handlers. This report, along with the companion report documenting the algorithms developed, Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units (Fernandez et al. 2009), document the work performed and results of this project.

  16. Smart HVAC Control in IoT: Energy Consumption Minimization with User Comfort Constraints

    Directory of Open Access Journals (Sweden)

    Jordi Serra

    2014-01-01

    of heating, ventilation, and air conditioning (HVAC systems in smart grids with variable energy price. To that end, first, we propose an energy scheduling method that minimizes the energy consumption cost for a particular time interval, taking into account the energy price and a set of comfort constraints, that is, a range of temperatures according to user’s preferences for a given room. Then, we propose an energy scheduler where the user may select to relax the temperature constraints to save more energy. Moreover, thanks to the IoT paradigm, the user may interact remotely with the HVAC control system. In particular, the user may decide remotely the temperature of comfort, while the temperature and energy consumption information is sent through Internet and displayed at the end user’s device. The proposed algorithms have been implemented in a real testbed, highlighting the potential gains that can be achieved in terms of both energy and cost.

  17. A Statistical Approach for Selecting Buildings for Experimental Measurement of HVAC Needs

    Directory of Open Access Journals (Sweden)

    Malinowski Paweł

    2017-03-01

    Full Text Available This article presents a statistical methodology for selecting representative buildings for experimentally evaluating the performance of HVAC systems, especially in terms of energy consumption. The proposed approach is based on the k-means method. The algorithm for this method is conceptually simple, allowing it to be easily implemented. The method can be applied to large quantities of data with unknown distributions. The method was tested using numerical experiments to determine the hourly, daily, and yearly heat values and the domestic hot water demands of residential buildings in Poland. Due to its simplicity, the proposed approach is very promising for use in engineering applications and is applicable to testing the performance of many HVAC systems.

  18. Practical Study on HVAC Control Technology Based on the Learning Function and Optimum Multiple Objective Processes

    Science.gov (United States)

    Ueda, Haruka; Dazai, Ryota; Kaseda, Chosei; Ikaga, Toshiharu; Kato, Akihiro

    Demand among large office buildings for the energy-saving benefits of the HVAC (Heating, Ventilating and Air-Conditioning) System are increasing as more and more people become concerned with global environmental issues. However, immoderate measures taken in the interest of energy conservation may encroach on the thermal comfort and productivity level of office workers. Building management should satisfy both indoor thermal comfort and energy conservation while adapting to the many regulatory, social, climate, and other changes that occur during the lifespan of the building. This paper demonstrates how optimal control of the HVAC system, based on data modeling and the multi-objective optimal method, achieves an efficient equilibrium between thermal comfort and energy conservation.

  19. DEVELOPMENT OF THE OPTIMAL CONTROL MODEL FOR HVAC SYSTEM AND ITS APPLICATION%通风空调系统最优控制模型的开发及应用

    Institute of Scientific and Technical Information of China (English)

    刘贤坤; 董超俊

    2002-01-01

    对某一通风空调(HVAC)系统进行了实验,利用实验结果采用多变量自回归的方法开发了适用于HVAC系统控制的数学模型,该数字模型用于带有前馈补偿的线性二次高斯控制(LQG),控制房间的温度和湿度,大大改善了控制性能,提高了HVAC系统的稳定性.

  20. Efficient HVAC. New products; Climatización eficiente. Nuevos productos

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-07-01

    Jung is responding to the challenge of energy efficiency, ease of operation and economic profitability in all of its solutions for the tertiary sector, whether for newly constructed buildings or refurbishments, for full management of the electrical system or the partial control of lighting, HVAC, mood settings, access control, etc., for the bedrooms or specific areas of the building. In the specific case of hotels, Jung offers each a custom-made solution in line with its possibilities and objectives. (Author)

  1. Designing Forced-Air HVAC Systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-08-31

    This guide explains proper calculation of heating and cooling design loads for homes.used to calculated for the home using the protocols set forth in the latest edition of the Air Conditioning Contractors of America’s (ACCA) Manual J (currently the 8th edition), ASHRAE 2009 Handbook of Fundamentals, or an equivalent computation procedure.

  2. Choosing a Geothermal as an HVAC System.

    Science.gov (United States)

    Lensenbigler, John D.

    2002-01-01

    Describes the process of selecting and installing geothermal water source heat pumps for new residence halls at Johnson Bible College in Knoxville, Tennessee, including choosing the type of geothermal design, contractors, and interior equipment, and cost and payback. (EV)

  3. Choosing a Geothermal as an HVAC System.

    Science.gov (United States)

    Lensenbigler, John D.

    2002-01-01

    Describes the process of selecting and installing geothermal water source heat pumps for new residence halls at Johnson Bible College in Knoxville, Tennessee, including choosing the type of geothermal design, contractors, and interior equipment, and cost and payback. (EV)

  4. Strategy Guideline: Transitioning HVAC Companies to Whole House Performance Contractors

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, A.

    2012-05-01

    This report describes the findings from research IBACOS conducted related to heating, ventilation, and air conditioning (HVAC) companies who have made the decision to transition to whole house performance contracting (WHPC).

  5. Strategy Guideline. Transitioning HVAC Companies to Whole House Performance Contractors

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, Arlan [IBACOS, Inc., Pittsburgh, PA (United States)

    2012-05-01

    This report describes the findings from research IBACOS conducted related to heating, ventilation, and air conditioning (HVAC) companies who have made the decision to transition to whole house performance contracting (WHPC).

  6. The HVAC Control Technology Making Energy Saving Compatible with Comfort

    National Research Council Canada - National Science Library

    高木, 康夫; 米沢, 憲造; 村山, 大; 西村, 信孝; 花田, 雄一; 山崎, 謙一

    2010-01-01

    .... The method is mainly focused on the compatibility of energy savings and comfort. The energy saving is achieved through the next generation air handling unit that controls room humidity without energy loss and the optimal operation of HVAC...

  7. Designing the controllability of a HVAC-plant by dynamic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Novakovic, V.; Grindal, A.

    1994-05-01

    This paper was presented at CLIMA 2000 - The international conference on energy and environmental matters in built environment, London, 1.-3. November 1993. Nowadays, HVAC engineers can use dynamic simulation programs in their everyday work. Such tools provide the ability to analyze different system configurations and to check the obtained states even before the building and plant are constructed. To encourage its wider use, the authors present in this paper the experiences obtained with the simulation program HVAC-DYNAMICS. The program was used to simulate the retrofitting of a heat recovery wheel to a conventional ventilation plant with a hot water heating coil. The effects of different design parameters on the controllability of the plant were investigated. Interestingly, some commonly recommended ``clever`` configurations can lead to unexpected control scenarios. 4 refs., 3 figs., 2 tabs.

  8. DYNAMICAL CONSISTENCE IN 3-DIMENSIONAL TYPE-K COMPETITIVE LOTKA-VOLTERRA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper. Two discretization schemes are applied to the system with an positive interior fixed point, and two corresponding discrete systems are obtained. By analyzing the local dynamics of the corresponding discrete system near the interior fixed point, it is showed that this system is not dynamically consistent with the continuous counterpart system.

  9. Comparison of methods to evaluate the fungal biomass in heating, ventilation, and air-conditioning (HVAC) dust.

    Science.gov (United States)

    Biyeyeme Bi Mve, Marie-Jeanne; Cloutier, Yves; Lacombe, Nancy; Lavoie, Jacques; Debia, Maximilien; Marchand, Geneviève

    2016-12-01

    Heating, ventilation, and air-conditioning (HVAC) systems contain dust that can be contaminated with fungal spores (molds), which may have harmful effects on the respiratory health of the occupants of a building. HVAC cleaning is often based on visual inspection of the quantity of dust, without taking the mold content into account. The purpose of this study is to propose a method to estimate fungal contamination of dust in HVAC systems. Comparisons of different analytical methods were carried out on dust deposited in a controlled-atmosphere exposure chamber. Sixty samples were analyzed using four methods: culture, direct microscopic spore count (DMSC), β-N-acetylhexosaminidase (NAHA) dosing and qPCR. For each method, the limit of detection, replicability, and repeatability were assessed. The Pearson correlation coefficients between the methods were also evaluated. Depending on the analytical method, mean spore concentrations per 100 cm(2) of dust ranged from 10,000 to 682,000. Limits of detection varied from 120 to 217,000 spores/100 cm(2). Replicability and repeatability were between 1 and 15%. Pearson correlation coefficients varied from -0.217 to 0.83. The 18S qPCR showed the best sensitivity and precision, as well as the best correlation with the culture method. PCR targets only molds, and a total count of fungal DNA is obtained. Among the methods, mold DNA amplification by qPCR is the method suggested for estimating the fungal content found in dust of HVAC systems.

  10. Integrated Control of air distribution system noise-- A nuclear power plant control room HVAC system%空气输配系统噪声综合控制研究--某核电厂主控室暖通空调系统

    Institute of Scientific and Technical Information of China (English)

    刘海成

    2016-01-01

    China has built nuclear power plant main control room noise value agreed to 56dB (A) or so, after the noise control noise is 53dB (A) or so. However, according to relevant national standards, environmental noise limits for new projects main control room to achieve 45dB (A). Accordingly, the monitoring of operating nuclear power plants in the main control room noise, room sound field simulation and identify sound sources, found that: air HVAC system noise of the air distribution system to produce secondary duct itself radiated noise excitation is sound and solid the main source of indoor master acoustic environment. Studies have shown that: the main factors vent excessive noise muffler system design is unreasonable, the system calculation inaccurate flow noise, noise reduction equipment and system performance is not reasonable match and the lack of relevant engineering experience. In this paper, the problems identified, the system describes the different mechanisms produce noise with different noise reduction measures should be analyzed wind pipe itself radiated noise excitation and solid sound excessivecountermeasures, and from the HVAC system controls air distribution system starting noise, it made a similar noise reduction reference integrated HVAC systems solutions.%我国已建成的核电厂主控室内噪声值约定为56dB(A)左右,经噪声控制后噪声值为53dB(A)左右。但是根据有关国家标准的要求,新建项目主控室的环境噪声限值要达到45dB (A)。据此,监测在运行核电厂主控室内噪声,识别室内声场模拟及声源,发现:暖通空调系统之空气输配系统产生的风口噪声、风管本身辐射的二次激发噪声及固体声是主控室内声环境的最主要声源。研究表明:风口噪声超标主要因素有系统消声设计不合理,系统气流再生噪声计算不精确,消声设备性能与系统未合理匹配及缺乏相关工程经验等。本文针对问题

  11. CONSISTENCY OF THE PERFORMANCE MANAGEMENT SYSTEM AND ITS QUANTIFICATION USING THE Z-MESOT FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Jan Zavadsky

    2016-12-01

    Full Text Available The main purpose of this paper is: (1 to present the theoretical approach for testing a performance management system`s consistency using the Z-MESOT framework and (2 to present the results of empirical analysis in selected manufacturing companies. The Z-MESOT framework is a managerial approach, based on the definitions of attributes for measuring and assessing the performance of a company. It is a quantitative approach which can proof the degree of the performance management system`s consistency. The quantification comes from arithmetical calculation in the Z-MESOT matrix. The consistency of the performance management system does not assure the final performance. Consistency is a part of the systemic approach to the management even if we do not call it as quality management. A consistent definition of the performance management system can help enterprises to be flexible and to be able to quickly respond in the case of any changes in the internal or external business environment. A consistent definition is represented by a set of 21 performance indicator attributes including the requirement for measuring and evaluating strategic and operational goals. In the paper, we also describe the relationships between selected requirements of the ISO 9001:2015 standard and the Z-MESOT framework.

  12. Method used to test the imaging consistency of binocular camera's left-right optical system

    Science.gov (United States)

    Liu, Meiying; Wang, Hu; Liu, Jie; Xue, Yaoke; Yang, Shaodong; Zhao, Hui

    2016-09-01

    To binocular camera, the consistency of optical parameters of the left and the right optical system is an important factor that will influence the overall imaging consistency. In conventional testing procedure of optical system, there lacks specifications suitable for evaluating imaging consistency. In this paper, considering the special requirements of binocular optical imaging system, a method used to measure the imaging consistency of binocular camera is presented. Based on this method, a measurement system which is composed of an integrating sphere, a rotary table and a CMOS camera has been established. First, let the left and the right optical system capture images in normal exposure time under the same condition. Second, a contour image is obtained based on the multiple threshold segmentation result and the boundary is determined using the slope of contour lines near the pseudo-contour line. Third, the constraint of gray level based on the corresponding coordinates of left-right images is established and the imaging consistency could be evaluated through standard deviation σ of the imaging grayscale difference D (x, y) between the left and right optical system. The experiments demonstrate that the method is suitable for carrying out the imaging consistency testing for binocular camera. When the standard deviation 3σ distribution of imaging gray difference D (x, y) between the left and right optical system of the binocular camera does not exceed 5%, it is believed that the design requirements have been achieved. This method could be used effectively and paves the way for the imaging consistency testing of the binocular camera.

  13. A reliable p ower management scheme for consistent hashing based distributed key value storage systems#

    Institute of Scientific and Technical Information of China (English)

    Nan-nan ZHAO; Ji-guang WAN; Jun WANG; Chang-sheng XIE

    2016-01-01

    Distributed key value storage systems are among the most important types of distributed storage systems currently deployed in data centers. Nowadays, enterprise data centers are facing growing pressure in reducing their power consumption. In this paper, we propose GreenCHT, a reliable power management scheme for consistent hashing based distributed key value storage systems. It consists of a multi-tier replication scheme, a reliable distributed log store, and a predictive power mode scheduler (PMS). Instead of randomly placing replicas of each object on a number of nodes in the consistent hash ring, we arrange the replicas of objects on nonoverlapping tiers of nodes in the ring. This allows the system to fall in various power modes by powering down subsets of servers while not violating data availability. The predictive PMS predicts workloads and adapts to load fluctuation. It cooperates with the multi-tier replication strategy to provide power proportionality for the system. To ensure that the reliability of the system is maintained when replicas are powered down, we distribute the writes to standby replicas to active servers, which ensures failure tolerance of the system. GreenCHT is implemented based on Sheepdog, a distributed key value storage system that uses consistent hashing as an underlying distributed hash table. By replaying 12 typical real workload traces collected from Microsoft, the evaluation results show that GreenCHT can provide significant power savings while maintaining a desired performance. We observe that GreenCHT can reduce power consumption by up to 35%–61%.

  14. The Development of Australia's National Training System: A Dynamic Tension between Consistency and Flexibility. Occasional Paper

    Science.gov (United States)

    Bowman, Kaye; McKenna, Suzy

    2016-01-01

    This occasional paper provides an overview of the development of Australia's national training system and is a key knowledge document of a wider research project "Consistency with flexibility in the Australian national training system." This research project investigates the various approaches undertaken by each of the jurisdictions to…

  15. A consistent description of kinetics and hydrodynamics of quantum Bose-systems

    Directory of Open Access Journals (Sweden)

    P.A.Hlushak

    2004-01-01

    Full Text Available A consistent approach to the description of kinetics and hydrodynamics of many-Boson systems is proposed. The generalized transport equations for strongly and weakly nonequilibrium Bose systems are obtained. Here we use the method of nonequilibrium statistical operator by D.N. Zubarev. New equations for the time distribution function of the quantum Bose system with a separate contribution from both the kinetic and potential energies of particle interactions are obtained. The generalized transport coefficients are determined accounting for the consistent description of kinetic and hydrodynamic processes.

  16. On the Lagrangian structure of 3D consistent systems of asymmetric quad-equations

    CERN Document Server

    Boll, Raphael

    2011-01-01

    Recently, the first-named author gave a classification of 3D consistent 6-tuples of quad-equations with the tetrahedron property; several novel asymmetric 6-tuples have been found. Due to 3D consistency, these 6-tuples can be extended to discrete integrable systems on Z^m. We establish Lagrangian structures and flip-invariance of the action functional for the class of discrete integrable systems involving equations for which some of the biquadratics are non-degenerate and some are degenerate. This class covers, among others, some of the above mentioned novel systems.

  17. Quantum thermal transport through anharmonic systems: A self-consistent approach

    Science.gov (United States)

    He, Dahai; Thingna, Juzar; Wang, Jian-Sheng; Li, Baowen

    2016-10-01

    We propose a feasible and effective approach to study quantum thermal transport through anharmonic systems. The main idea is to obtain an effective harmonic Hamiltonian for the anharmonic system by applying the self-consistent phonon theory. By using the effective harmonic Hamiltonian, we study thermal transport within the framework of the nonequilibrium Green's function method using the celebrated Caroli formula. We corroborate our quantum self-consistent approach by using the quantum master equation that can deal with anharmonicity exactly, but is limited to the weak system-bath coupling regime. Finally, in order to demonstrate its strength, we apply the quantum self-consistent approach to study thermal rectification in a weakly coupled two-segment anharmonic system.

  18. Cogntive Consistency Analysis in Adaptive Bio-Metric Authentication System Design

    Directory of Open Access Journals (Sweden)

    Gahangir Hossain

    2015-07-01

    Full Text Available Cognitive consistency analysis aims to continuously monitor one's perception equilibrium towards successful accomplishment of cognitive task. Opposite to cognitive flexibility analysis – cognitive consistency analysis identifies monotone of perception towards successful interaction process (e.g., biometric authentication and useful in generation of decision support to assist one in need. This study consider fingertip dynamics (e.g., keystroke, tapping, clicking etc. to have insights on instantaneous cognitive states and its effects in monotonic advancement towards successful authentication process. Keystroke dynamics and tapping dynamics are analyzed based on response time data. Finally, cognitive consistency and confusion (inconsistency are computed with Maximal Information Coefficient (MIC and Maximal Asymmetry Score (MAS, respectively. Our preliminary study indicates that a balance between cognitive consistency and flexibility are needed in successful authentication process. Moreover, adaptive and cognitive interaction system requires in depth analysis of user’s cognitive consistency to provide a robust and useful assistance.

  19. Energization of Long HVAC Cables in Parallel - Analysis and Estimation Formulas

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth

    2012-01-01

    The installation of long HVAC cables has recently become more common and it tends to increase during the next years. Consequently, the energization of long HVAC cables in parallel is also a more common condition. The energization of HVAC cables in parallel resembles the en-ergization of capacitor...

  20. 10 CFR 431.402 - Preemption of State regulations for commercial HVAC & WH products.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Preemption of State regulations for commercial HVAC & WH... regulations for commercial HVAC & WH products. Beginning on the effective date of such standard, an energy conservation standard set forth in this Part for a commercial HVAC & WH product supersedes any State or...

  1. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Instructor Edition. Introduction to Construction Series.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructor's guide contains the materials required to teach a competency-based introductory course in heating, ventilating, and air conditioning (HVAC) to students who have chosen to explore careers in construction. It contains three units: HVAC materials, HVAC tools, and applied skills. Each instructional unit includes some or all of the…

  2. Introduction to Heating, Ventilation and Air Conditioning (HVAC). Instructor Edition. Introduction to Construction Series.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This instructor's guide contains the materials required to teach a competency-based introductory course in heating, ventilating, and air conditioning (HVAC) to students who have chosen to explore careers in construction. It contains three units: HVAC materials, HVAC tools, and applied skills. Each instructional unit includes some or all of the…

  3. Deposition of biological aerosols on HVAC heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, Jeffrey; Walker, Ian

    2001-09-01

    Many biologically active materials are transported as bioaerosols 1-10 {micro}m in diameter. These particles can deposit on cooling and heating coils and lead to serious indoor air quality problems. This paper investigates several of the mechanisms that lead to aerosol deposition on fin and tube heat exchangers. A model has been developed that incorporates the effects of several deposition mechanisms, including impaction, Brownian and turbulent diffusion, turbophoresis, thermophoresis, diffusiophoresis, and gravitational settling. The model is applied to a typical range of air velocities that are found in commercial and residential HVAC systems 1 - 6 m/s (200 - 1200 ft/min), particle diameters from 1 - 8 {micro}m, and fin spacings from 3.2 - 7.9 fins/cm (8 - 16 fins/inch or FPI). The results from the model are compared to results from an experimental apparatus that directly measures deposition on a 4.7 fins/cm (12 FPI) coil. The model agrees reasonably well with this measured data and suggests that cooling coils are an important sink for biological aerosols and consequently a potential source of indoor air quality problems.

  4. Numerical experiments on consistent horizontal and vertical resolution for atmospheric models and observing systems

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Lindzen, Richard S.

    1993-01-01

    Simple numerical experiments are performed in order to determine the effects of inconsistent combinations of horizontal and vertical resolution in both atmospheric models and observing systems. In both cases, we find that inconsistent spatial resolution is associated with enhanced noise generation. A rather fine horizontal resolution in a satellite-data observing system seems to be excessive when combined with the usually available relatively coarse vertical resolution. Using horizontal filters of different strengths, adjusted in such a way as to render the effective horizontal resolution more consistent with vertical resolution for the observing system, may result in improvement of the analysis accuracy. The increase of vertical resolution for a satellite data observing system with better vertically resolved data, the results are different in that little or no horizontal filtering is needed to make spatial resolution more consistent for the system. The obtained experimental estimates of consistent vertical and effective horizontal resolution are in a general agreement with consistent resolution estimates previously derived theoretically by the authors.

  5. Integrable motion of curves in self-consistent potentials: Relation to spin systems and soliton equations

    Energy Technology Data Exchange (ETDEWEB)

    Myrzakulov, R.; Mamyrbekova, G.K.; Nugmanova, G.N.; Yesmakhanova, K.R. [Eurasian International Center for Theoretical Physics and Department of General and Theoretical Physics, Eurasian National University, Astana 010008 (Kazakhstan); Lakshmanan, M., E-mail: lakshman@cnld.bdu.ac.in [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024 (India)

    2014-06-13

    Motion of curves and surfaces in R{sup 3} lead to nonlinear evolution equations which are often integrable. They are also intimately connected to the dynamics of spin chains in the continuum limit and integrable soliton systems through geometric and gauge symmetric connections/equivalence. Here we point out the fact that a more general situation in which the curves evolve in the presence of additional self-consistent vector potentials can lead to interesting generalized spin systems with self-consistent potentials or soliton equations with self-consistent potentials. We obtain the general form of the evolution equations of underlying curves and report specific examples of generalized spin chains and soliton equations. These include principal chiral model and various Myrzakulov spin equations in (1+1) dimensions and their geometrically equivalent generalized nonlinear Schrödinger (NLS) family of equations, including Hirota–Maxwell–Bloch equations, all in the presence of self-consistent potential fields. The associated gauge equivalent Lax pairs are also presented to confirm their integrability. - Highlights: • Geometry of continuum spin chain with self-consistent potentials explored. • Mapping on moving space curves in R{sup 3} in the presence of potential fields carried out. • Equivalent generalized nonlinear Schrödinger (NLS) family of equations identified. • Integrability of identified nonlinear systems proved by deducing appropriate Lax pairs.

  6. Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas

    2009-12-31

    This report documents the self-correction algorithms developed in the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls project funded jointly by the Bonneville Power Administration and the Building Technologies Program of the U.S. Department of Energy. The algorithms address faults for temperature sensors, humidity sensors, and dampers in air-handling units and correction of persistent manual overrides of automated control systems. All faults considered create energy waste when left uncorrected as is frequently the case in actual systems.

  7. Discretizing LTI Descriptor (Regular Differential Input Systems with Consistent Initial Conditions

    Directory of Open Access Journals (Sweden)

    Athanasios D. Karageorgos

    2010-01-01

    Full Text Available A technique for discretizing efficiently the solution of a Linear descriptor (regular differential input system with consistent initial conditions, and Time-Invariant coefficients (LTI is introduced and fully discussed. Additionally, an upper bound for the error ‖x¯(kT−x¯k‖ that derives from the procedure of discretization is also provided. Practically speaking, we are interested in such kind of systems, since they are inherent in many physical, economical and engineering phenomena.

  8. The convergence of the modified Gauss-Seidel methods for consistent linear systems

    Science.gov (United States)

    Li, Wen

    2003-05-01

    In this paper we present a convergence analysis for the modified Gauss-Seidel methods given in Gunawardena et al. (Linear Algebra Appl. 154-156 (1991) 125) and Kohno et al. (Linear Algebra Appl. 267 (1997) 113) for consistent linear systems. We prove that the modified Gauss-Seidel method converges for some values of the parameters in the preconditioned matrix.

  9. Airflow Measurement of the Car HVAC Unit Using Hot-wire Anemometry

    Directory of Open Access Journals (Sweden)

    Fojtlín Miloš

    2016-01-01

    Full Text Available Thermal environment in a vehicular cabin significantly influence drivers’ fatigue and passengers’ thermal comfort. This environment is traditionally managed by HVAC cabin system that distributes air and modifies its properties. In order to simulate cabin thermal behaviour, amount of the air led through car vents must be determined. The aim of this study was to develop methodology to measure airflow from the vents, and consequently calculate corresponding air distribution coefficients. Three climatic cases were selected to match European winter, summer, and spring / fall conditions. Experiments were conducted on a test vehicle in a climatic chamber. The car HVAC system was set to automatic control mode, and the measurements were executed after the system stabilisation—each case was independently measured three times. To be able to evaluate precision of the method, the airflow was determined at the system inlet (HVAC suction and outlet (each vent, and the total airflow values were compared. The airflow was calculated by determining a mean value of the air velocity multiplied by an area of inlet / outlet cross-section. Hot-wire anemometry was involved to measure the air velocity. Regarding the summer case, total airflow entering the cabin was around 57 l s-1 with 60 % of the air entering the cabin through dashboard vents; no air was supplied to the feet compartment. The remaining cases had the same total airflow of around 42 l s-1, and the air distribution was focused mainly on feet and windows. The inlet and outlet airflow values show a good match with a maximum mass differential of 8.3 %.

  10. Airflow Measurement of the Car HVAC Unit Using Hot-wire Anemometry

    Science.gov (United States)

    Fojtlín, Miloš; Planka, Michal; Fišer, Jan; Pokorný, Jan; Jícha, Miroslav

    2016-03-01

    Thermal environment in a vehicular cabin significantly influence drivers' fatigue and passengers' thermal comfort. This environment is traditionally managed by HVAC cabin system that distributes air and modifies its properties. In order to simulate cabin thermal behaviour, amount of the air led through car vents must be determined. The aim of this study was to develop methodology to measure airflow from the vents, and consequently calculate corresponding air distribution coefficients. Three climatic cases were selected to match European winter, summer, and spring / fall conditions. Experiments were conducted on a test vehicle in a climatic chamber. The car HVAC system was set to automatic control mode, and the measurements were executed after the system stabilisation—each case was independently measured three times. To be able to evaluate precision of the method, the airflow was determined at the system inlet (HVAC suction) and outlet (each vent), and the total airflow values were compared. The airflow was calculated by determining a mean value of the air velocity multiplied by an area of inlet / outlet cross-section. Hot-wire anemometry was involved to measure the air velocity. Regarding the summer case, total airflow entering the cabin was around 57 l s-1 with 60 % of the air entering the cabin through dashboard vents; no air was supplied to the feet compartment. The remaining cases had the same total airflow of around 42 l s-1, and the air distribution was focused mainly on feet and windows. The inlet and outlet airflow values show a good match with a maximum mass differential of 8.3 %.

  11. Ventilation, temperature, and HVAC characteristics in small and medium commercial buildings in California.

    Science.gov (United States)

    Bennett, D H; Fisk, W; Apte, M G; Wu, X; Trout, A; Faulkner, D; Sullivan, D

    2012-08-01

    This field study of 37 small and medium commercial buildings throughout California obtained information on ventilation rate, temperature, and heating, ventilating, and air-conditioning (HVAC) system characteristics. The study included seven retail establishments; five restaurants; eight offices; two each of gas stations, hair salons, healthcare facilities, grocery stores, dental offices, and fitness centers; and five other buildings. Fourteen (38%) of the buildings either could not or did not provide outdoor air through the HVAC system. The air exchange rate averaged 1.6 (s.d. = 1.7) exchanges per hour and was similar between buildings with and without outdoor air supplied through the HVAC system, indicating that some buildings have significant leakage or ventilation through open windows and doors. Not all buildings had sufficient air exchange to meet ASHRAE 62.1 Standards, including buildings used for fitness centers, hair salons, offices, and retail establishments. The majority of the time, buildings were within the ASHRAE temperature comfort range. Offices were frequently overcooled in the summer. All of the buildings had filters, but over half the buildings had a filter with a minimum efficiency reporting value rating of 4 or lower, which are not very effective for removing fine particles. Most U.S. commercial buildings (96%) are small- to medium-sized, using nearly 18% of the country's energy, and sheltering a large population daily. Little is known about the ventilation systems in these buildings. This study found a wide variety of ventilation conditions, with many buildings failing to meet relevant ventilation standards. Regulators may want to consider implementing more complete building inspections at commissioning and point of sale. © 2012 John Wiley & Sons A/S.

  12. The consistent Riccati expansion and new interaction solution for a Boussinesq-type coupled system

    Science.gov (United States)

    Ruan, Shao-Qing; Yu, Wei-Feng; Yu, Jun; Yu, Guo-Xiang

    2015-06-01

    Starting from the Davey-Stewartson equation, a Boussinesq-type coupled equation system is obtained by using a variable separation approach. For the Boussinesq-type coupled equation system, its consistent Riccati expansion (CRE) solvability is studied with the help of a Riccati equation. It is significant that the soliton-cnoidal wave interaction solution, expressed explicitly by Jacobi elliptic functions and the third type of incomplete elliptic integral, of the system is also given. Project supported by the National Natural Science Foundation of China (Grant No. 11275129).

  13. Reducing Building HVAC Costs with Site-Recovery Energy

    Science.gov (United States)

    Pargeter, Stephen J.

    2012-01-01

    Building owners are caught between two powerful forces--the need to lower energy costs and the need to meet or exceed outdoor air ventilation regulations for occupant health and comfort. Large amounts of energy are wasted each day from commercial, institutional, and government building sites as heating, ventilation, and air conditioning (HVAC)…

  14. Illinois Occupational Skill Standards: HVAC/R Technician Cluster.

    Science.gov (United States)

    Illinois Occupational Skill Standards and Credentialing Council, Carbondale.

    This document, which is intended to serve as a guide for work force preparation program providers, details the Illinois occupational skill standards for programs preparing students for employment in jobs in the heating, ventilation, air conditioning, and refrigeration (HVAC/R) industry. Agency partners involved in this project include: the…

  15. Maximize Benefits, Minimize Risk: Selecting the Right HVAC Firm.

    Science.gov (United States)

    Golden, James T.

    1993-01-01

    An informal survey of 20 major urban school districts found that 40% were currently operating in a "break down" maintenance mode. A majority, 57.9%, also indicated they saw considerable benefits in contracting for heating, ventilating, and air conditioning (HVAC) maintenance services with outside firms. Offers guidelines in selecting HVAC…

  16. Maximize Benefits, Minimize Risk: Selecting the Right HVAC Firm.

    Science.gov (United States)

    Golden, James T.

    1993-01-01

    An informal survey of 20 major urban school districts found that 40% were currently operating in a "break down" maintenance mode. A majority, 57.9%, also indicated they saw considerable benefits in contracting for heating, ventilating, and air conditioning (HVAC) maintenance services with outside firms. Offers guidelines in selecting…

  17. Loss evaluation of HVAC and HVDC transmission solutions for large offshore wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Negra, N. Barberis [Politecnico of Turin, Department of Electrical Engineering (Italy); Todorovic, J. [ELEKTROPRENOS, Banja Luka (Bosnia and Herzegovina); Ackermann, T. [Royal Institute of Technology, Teknikringen 33, 10044 Stockholm (Sweden)

    2006-07-15

    This paper presents a comparison of transmission losses for different technical transmission solutions for large offshore wind farms. Three technical solutions are analyzed, i.e. HVAC, HVDC Line Commutated Converter (LCC) and HVDC Voltage Source Converter (VSC). The losses for each technology are calculated for wind farms with different ratings and various distances to shore. In addition, solutions with combinations of two and the three different transmission technologies are analyzed and compared. Based on this comparison, further analysis regarding the economical feasibility can be performed in order to determine the most economic solutions for the transmission system of an offshore wind farm. (author)

  18. RELIABILITY ASSESSMENT OF ENTROPY METHOD FOR SYSTEM CONSISTED OF IDENTICAL EXPONENTIAL UNITS

    Institute of Scientific and Technical Information of China (English)

    Sun Youchao; Shi Jun

    2004-01-01

    The reliability assessment of unit-system near two levels is the most important content in the reliability multi-level synthesis of complex systems. Introducing the information theory into system reliability assessment, using the addible characteristic of information quantity and the principle of equivalence of information quantity, an entropy method of data information conversion is presented for the system consisted of identical exponential units. The basic conversion formulae of entropy method of unit test data are derived based on the principle of information quantity equivalence. The general models of entropy method synthesis assessment for system reliability approximate lower limits are established according to the fundamental principle of the unit reliability assessment. The applications of the entropy method are discussed by way of practical examples. Compared with the traditional methods, the entropy method is found to be valid and practicable and the assessment results are very satisfactory.

  19. Analytical model for effect of temperature variation on PSF consistency in wavefront coding infrared imaging system

    Science.gov (United States)

    Feng, Bin; Shi, Zelin; Zhang, Chengshuo; Xu, Baoshu; Zhang, Xiaodong

    2016-05-01

    The point spread function (PSF) inconsistency caused by temperature variation leads to artifacts in decoded images of a wavefront coding infrared imaging system. Therefore, this paper proposes an analytical model for the effect of temperature variation on the PSF consistency. In the proposed model, a formula for the thermal deformation of an optical phase mask is derived. This formula indicates that a cubic optical phase mask (CPM) is still cubic after thermal deformation. A proposed equivalent cubic phase mask (E-CPM) is a virtual and room-temperature lens which characterizes the optical effect of temperature variation on the CPM. Additionally, a calculating method for PSF consistency after temperature variation is presented. Numerical simulation illustrates the validity of the proposed model and some significant conclusions are drawn. Given the form parameter, the PSF consistency achieved by a Ge-material CPM is better than the PSF consistency by a ZnSe-material CPM. The effect of the optical phase mask on PSF inconsistency is much slighter than that of the auxiliary lens group. A large form parameter of the CPM will introduce large defocus-insensitive aberrations, which improves the PSF consistency but degrades the room-temperature MTF.

  20. Automated Verification of Memory Consistencies of DSM System on Unified Framework

    Directory of Open Access Journals (Sweden)

    Dr. Pankaj Kumar , Durgesh Kumar

    2012-12-01

    Full Text Available The consistency model of a DSM system specifies the ordering constraints on concurrent memory accesses by multiple processors, and hence has fundamental impact on DSM systems’ programming convenience and implementation efficiency. We have proposed the structural model for automated verification of memory consistencies of DSM System. DSM allows processes to assume a globally shared virtual memory even though they execute on nodes that do not physically share memory. The DSM software provide the abstraction of a globally shared memory in which each processor can access any data item without the programmer having to worry about where the data is or how to obtain its value In contrast in the native programming model on networks of workstations message passing the programmer must decide when a processor needs to communicate with whom to communicate and what data to be send. On a DSM system the programmer can focus on algorithmic development rather than on managing partitioned data sets and communicating values. The programming interfaces to DSM systems may differ in a variety of respects. The memory model refers to how updates to distributed shared memory are rejected to the processes in the system. The most intuitive model of distributed shared memory is that a read should always return the last value written unfortunately the notion of the last value written is not well defined in a distributed system.

  1. Metabolic Effects of Dietary Proteins, Amino Acids and The Other Amine Consisting Compounds on Cardiovascular System.

    OpenAIRE

    Elif Uğur; Reyhan Nergiz Ünal

    2017-01-01

    During the prevention and treatment of cardiovascular diseases, first cause of deaths in the world, diet has a vital role. While nutrition programs for the cardiovascular health generally focus on lipids and carbohydrates, effects of proteins are not well concerned. Thus this review is written in order to examine effect of proteins, amino acids, and the other amine consisting compounds on cardiovascular system. Because of that animal or plant derived proteins have different protein compositio...

  2. Dielectric screening in extended systems using the self-consistent Sternheimer equation and localized basis sets

    OpenAIRE

    2012-01-01

    We develop a first-principles computational method for investigating the dielectric screening in extended systems using the self-consistent Sternheimer equation and localized non-orthogonal basis sets. Our approach does not require the explicit calculation of unoccupied electronic states, only uses two-center integrals, and has a theoretical scaling of order O(N^3). We demonstrate this method by comparing our calculations for silicon, germanium, diamond, and LiCl with reference planewaves cal...

  3. The Consistency of Performance Management System Based on Attributes of the Performance Indicator: An Empirical Study

    Directory of Open Access Journals (Sweden)

    Jan Zavadsky

    2014-07-01

    Full Text Available Purpose: The performance management system (PMS is a metasystem over all business processes at the strategic and operational level. Effectiveness of the various management systems depends on many factors. One of them is the consistent definition of each system elements. The main purpose of this study is to explore if the performance management systems of the sample companies is consistent and how companies can create such a system. The consistency in this case is based on the homogenous definition of attributes relating to the performance indicator as a basic element of PMS.Methodology: At the beginning, we used an affinity diagram that helped us to clarify and to group various attributes of performance indicators. The main research results we achieved are through empirical study. The empirical study was carried out in a sample of Slovak companies. The criterion for selection was the existence of the certified management systems according to the ISO 9001. Representativeness of the sample companies was confirmed by application of Pearson´s chi-squared test (χ2 - test due to above standards. Findings: Coming from the review of various literature, we defined four groups of attributes relating to the performance indicator: formal attributes, attributes of target value, informational attributes and attributes of evaluation. The whole set contains 21 attributes. The consistency of PMS is based not on maximum or minimum number of attributes, but on the same type of attributes for each performance indicator used in PMS at both the operational and strategic level. The main findings are: companies use various financial and non-financial indicators at strategic or operational level; companies determine various attributes of performance indicator, but most of the performance indicators are otherwise determined; we identified the common attributes for the whole sample of companies. Practical implications: The research results have got an implication for

  4. Metabolic Effects of Dietary Proteins, Amino Acids and The Other Amine Consisting Compounds on Cardiovascular System.

    Directory of Open Access Journals (Sweden)

    Elif Uğur

    2017-01-01

    Full Text Available During the prevention and treatment of cardiovascular diseases, first cause of deaths in the world, diet has a vital role. While nutrition programs for the cardiovascular health generally focus on lipids and carbohydrates, effects of proteins are not well concerned. Thus this review is written in order to examine effect of proteins, amino acids, and the other amine consisting compounds on cardiovascular system. Because of that animal or plant derived proteins have different protein composition in different foods such as dairy products, egg, meat, chicken, fish, pulse and grains, their effects on blood pressure and regulation of lipid profile are unlike. In parallel amino acids made up proteins have different effect on cardiovascular system. From this point, sulfur containing amino acids, branched chain amino acids, aromatic amino acids, arginine, ornithine, citrulline, glycine, and glutamine may affect cardiovascular system in different metabolic pathways. In this context, one carbon metabolism, synthesis of hormone, stimulation of signaling pathways and effects of intermediate and final products that formed as a result of amino acids metabolism is determined. Despite the protein and amino acids, some other amine consisting compounds in diet include trimethylamine N-oxide, heterocyclic aromatic amines, polycyclic aromatic hydrocarbons and products of Maillard reaction. These amine consisting compounds generally increase the risk for cardiovascular diseases by stimulating oxidative stress, inflammation, and formation of atherosclerotic plaque.

  5. Synchronization in node of complex networks consist of complex chaotic system

    Directory of Open Access Journals (Sweden)

    Qiang Wei

    2014-07-01

    Full Text Available A new synchronization method is investigated for node of complex networks consists of complex chaotic system. When complex networks realize synchronization, different component of complex state variable synchronize up to different scaling complex function by a designed complex feedback controller. This paper change synchronization scaling function from real field to complex field for synchronization in node of complex networks with complex chaotic system. Synchronization in constant delay and time-varying coupling delay complex networks are investigated, respectively. Numerical simulations are provided to show the effectiveness of the proposed method.

  6. The self-consistent field model for Fermi systems with account of three-body interactions

    Directory of Open Access Journals (Sweden)

    Yu.M. Poluektov

    2015-12-01

    Full Text Available On the basis of a microscopic model of self-consistent field, the thermodynamics of the many-particle Fermi system at finite temperatures with account of three-body interactions is built and the quasiparticle equations of motion are obtained. It is shown that the delta-like three-body interaction gives no contribution into the self-consistent field, and the description of three-body forces requires their nonlocality to be taken into account. The spatially uniform system is considered in detail, and on the basis of the developed microscopic approach general formulas are derived for the fermion's effective mass and the system's equation of state with account of contribution from three-body forces. The effective mass and pressure are numerically calculated for the potential of "semi-transparent sphere" type at zero temperature. Expansions of the effective mass and pressure in powers of density are obtained. It is shown that, with account of only pair forces, the interaction of repulsive character reduces the quasiparticle effective mass relative to the mass of a free particle, and the attractive interaction raises the effective mass. The question of thermodynamic stability of the Fermi system is considered and the three-body repulsive interaction is shown to extend the region of stability of the system with the interparticle pair attraction. The quasiparticle energy spectrum is calculated with account of three-body forces.

  7. Incorporating rapid neocortical learning of new schema-consistent information into complementary learning systems theory.

    Science.gov (United States)

    McClelland, James L

    2013-11-01

    The complementary learning systems theory of the roles of hippocampus and neocortex (McClelland, McNaughton, & O'Reilly, 1995) holds that the rapid integration of arbitrary new information into neocortical structures is avoided to prevent catastrophic interference with structured knowledge representations stored in synaptic connections among neocortical neurons. Recent studies (Tse et al., 2007, 2011) showed that neocortical circuits can rapidly acquire new associations that are consistent with prior knowledge. The findings challenge the complementary learning systems theory as previously presented. However, new simulations extending those reported in McClelland et al. (1995) show that new information that is consistent with knowledge previously acquired by a putatively cortexlike artificial neural network can be learned rapidly and without interfering with existing knowledge; it is when inconsistent new knowledge is acquired quickly that catastrophic interference ensues. Several important features of the findings of Tse et al. (2007, 2011) are captured in these simulations, indicating that the neural network model used in McClelland et al. has characteristics in common with neocortical learning mechanisms. An additional simulation generalizes beyond the network model previously used, showing how the rate of change of cortical connections can depend on prior knowledge in an arguably more biologically plausible network architecture. In sum, the findings of Tse et al. are fully consistent with the idea that hippocampus and neocortex are complementary learning systems. Taken together, these findings and the simulations reported here advance our knowledge by bringing out the role of consistency of new experience with existing knowledge and demonstrating that the rate of change of connections in real and artificial neural networks can be strongly prior-knowledge dependent.

  8. A Boolean Consistent Fuzzy Inference System for Diagnosing Diseases and Its Application for Determining Peritonitis Likelihood

    Science.gov (United States)

    Dragović, Ivana; Turajlić, Nina; Pilčević, Dejan; Petrović, Bratislav; Radojević, Dragan

    2015-01-01

    Fuzzy inference systems (FIS) enable automated assessment and reasoning in a logically consistent manner akin to the way in which humans reason. However, since no conventional fuzzy set theory is in the Boolean frame, it is proposed that Boolean consistent fuzzy logic should be used in the evaluation of rules. The main distinction of this approach is that it requires the execution of a set of structural transformations before the actual values can be introduced, which can, in certain cases, lead to different results. While a Boolean consistent FIS could be used for establishing the diagnostic criteria for any given disease, in this paper it is applied for determining the likelihood of peritonitis, as the leading complication of peritoneal dialysis (PD). Given that patients could be located far away from healthcare institutions (as peritoneal dialysis is a form of home dialysis) the proposed Boolean consistent FIS would enable patients to easily estimate the likelihood of them having peritonitis (where a high likelihood would suggest that prompt treatment is indicated), when medical experts are not close at hand. PMID:27069500

  9. A Boolean Consistent Fuzzy Inference System for Diagnosing Diseases and Its Application for Determining Peritonitis Likelihood

    Directory of Open Access Journals (Sweden)

    Ivana Dragović

    2015-01-01

    Full Text Available Fuzzy inference systems (FIS enable automated assessment and reasoning in a logically consistent manner akin to the way in which humans reason. However, since no conventional fuzzy set theory is in the Boolean frame, it is proposed that Boolean consistent fuzzy logic should be used in the evaluation of rules. The main distinction of this approach is that it requires the execution of a set of structural transformations before the actual values can be introduced, which can, in certain cases, lead to different results. While a Boolean consistent FIS could be used for establishing the diagnostic criteria for any given disease, in this paper it is applied for determining the likelihood of peritonitis, as the leading complication of peritoneal dialysis (PD. Given that patients could be located far away from healthcare institutions (as peritoneal dialysis is a form of home dialysis the proposed Boolean consistent FIS would enable patients to easily estimate the likelihood of them having peritonitis (where a high likelihood would suggest that prompt treatment is indicated, when medical experts are not close at hand.

  10. A Boolean Consistent Fuzzy Inference System for Diagnosing Diseases and Its Application for Determining Peritonitis Likelihood.

    Science.gov (United States)

    Dragović, Ivana; Turajlić, Nina; Pilčević, Dejan; Petrović, Bratislav; Radojević, Dragan

    2015-01-01

    Fuzzy inference systems (FIS) enable automated assessment and reasoning in a logically consistent manner akin to the way in which humans reason. However, since no conventional fuzzy set theory is in the Boolean frame, it is proposed that Boolean consistent fuzzy logic should be used in the evaluation of rules. The main distinction of this approach is that it requires the execution of a set of structural transformations before the actual values can be introduced, which can, in certain cases, lead to different results. While a Boolean consistent FIS could be used for establishing the diagnostic criteria for any given disease, in this paper it is applied for determining the likelihood of peritonitis, as the leading complication of peritoneal dialysis (PD). Given that patients could be located far away from healthcare institutions (as peritoneal dialysis is a form of home dialysis) the proposed Boolean consistent FIS would enable patients to easily estimate the likelihood of them having peritonitis (where a high likelihood would suggest that prompt treatment is indicated), when medical experts are not close at hand.

  11. Self-consistent field theory based molecular dynamics with linear system-size scaling.

    Science.gov (United States)

    Richters, Dorothee; Kühne, Thomas D

    2014-04-01

    We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.

  12. Self-consistent field theory based molecular dynamics with linear system-size scaling

    Energy Technology Data Exchange (ETDEWEB)

    Richters, Dorothee [Institute of Mathematics and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 9, D-55128 Mainz (Germany); Kühne, Thomas D., E-mail: kuehne@uni-mainz.de [Institute of Physical Chemistry and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz (Germany); Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany)

    2014-04-07

    We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.

  13. Self-consistent models of quasi-relaxed rotating stellar systems

    CERN Document Server

    Varri, A L

    2012-01-01

    Two new families of self-consistent axisymmetric truncated equilibrium models for the description of quasi-relaxed rotating stellar systems are presented. The first extends the spherical King models to the case of solid-body rotation. The second is characterized by differential rotation, designed to be rigid in the central regions and to vanish in the outer parts, where the energy truncation becomes effective. The models are constructed by solving the nonlinear Poisson equation for the self-consistent mean-field potential. For rigidly rotating configurations, the solutions are obtained by an asymptotic expansion on the rotation strength parameter. The differentially rotating models are constructed by means of an iterative approach based on a Legendre series expansion of the density and the potential. The two classes of models exhibit complementary properties. The rigidly rotating configurations are flattened toward the equatorial plane, with deviations from spherical symmetry that increase with the distance f...

  14. Investigation on a Potential Targeting Drug Delivery System Consisting of Folate, Mitoxantrone and Human Serum Albumin

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiu-Jua; BI Ya-Jing; XIANG Jun-Feng; TANG Ya-Lin; YANG Qian-Fan; XU Guang-Zhi

    2008-01-01

    A potential targeting drug delivery system consisting of folate (FA), the targeting molecule, human serum al- bumin (HSA), the carrier, and mitoxantrone (MTO), the medicine, has been designed. Data obtained by UV absorp-tion, fluorescence, and NMR techniques indicated the formation of ternary complexes and possible application to building a targeting drug delivery system by using FA, MTO and HSA. Furthermore, cytotoxicity assay indicated that the toxicity of the FA-HSA-MTO against PC-3 cell line was 79.95%, which was much higher than that of free MTO tested in totally the same conditions. About 30% increase of the toxicity should be owed to the targeting ef-fect of FA. Thus, the feasibility and validity of a novel targeting drug delivery system, FA-HSA-MTO, was con-firmed.

  15. Building Environment Analysis based on Temperature and Humidity for Smart Energy Systems

    Science.gov (United States)

    Yun, Jaeseok; Won, Kwang-Ho

    2012-01-01

    In this paper, we propose a new HVAC (heating, ventilation, and air conditioning) control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment. PMID:23202004

  16. Building Environment Analysis Based on Temperature and Humidity for Smart Energy Systems

    Directory of Open Access Journals (Sweden)

    Kwang-Ho Won

    2012-10-01

    Full Text Available In this paper, we propose a new HVAC (heating, ventilation, and air conditioning control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment.

  17. Methods of information geometry in computational system biology (consistency between chemical and biological evolution).

    Science.gov (United States)

    Astakhov, Vadim

    2009-01-01

    Interest in simulation of large-scale metabolic networks, species development, and genesis of various diseases requires new simulation techniques to accommodate the high complexity of realistic biological networks. Information geometry and topological formalisms are proposed to analyze information processes. We analyze the complexity of large-scale biological networks as well as transition of the system functionality due to modification in the system architecture, system environment, and system components. The dynamic core model is developed. The term dynamic core is used to define a set of causally related network functions. Delocalization of dynamic core model provides a mathematical formalism to analyze migration of specific functions in biosystems which undergo structure transition induced by the environment. The term delocalization is used to describe these processes of migration. We constructed a holographic model with self-poetic dynamic cores which preserves functional properties under those transitions. Topological constraints such as Ricci flow and Pfaff dimension were found for statistical manifolds which represent biological networks. These constraints can provide insight on processes of degeneration and recovery which take place in large-scale networks. We would like to suggest that therapies which are able to effectively implement estimated constraints, will successfully adjust biological systems and recover altered functionality. Also, we mathematically formulate the hypothesis that there is a direct consistency between biological and chemical evolution. Any set of causal relations within a biological network has its dual reimplementation in the chemistry of the system environment.

  18. Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions.

    Science.gov (United States)

    Huang, R; Agranovski, I; Pyankov, O; Grinshpun, S

    2008-04-01

    Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approximately 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +/- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. Recirculated air in HVAC systems used for indoor air quality control in buildings often contains considerable number of viable bioaerosol particles because of limited efficiency of the filters installed in these systems. In the present study, we investigated - using aerosolized bacterial cells, bacterial and fungal spores, and virus-carrying particles - a novel idea of enhancing the performance of a low-efficiency HVAC filter utilizing continuous emission of unipolar ions in the filter vicinity. The findings described in

  19. Pair Fluctuations in Ultra-small Fermi Systems within Self-Consistent RPA at Finite Temperature

    CERN Document Server

    Storozhenko, A; Dukelsky, J; Röpke, G; Vdovin, A I

    2003-01-01

    A self-consistent version of the Thermal Random Phase Approximation (TSCRPA) is developed within the Matsubara Green's Function (GF) formalism. The TSCRPA is applied to the many level pairing model. The normal phase of the system is considered. The TSCRPA results are compared with the exact ones calculated for the Grand Canonical Ensemble. Advantages of the TSCRPA over the Thermal Mean Field Approximation (TMFA) and the standard Thermal Random Phase Approximation (TRPA) are demonstrated. Results for correlation functions, excitation energies, single particle level densities, etc., as a function of temperature are presented.

  20. Dielectric screening in extended systems using the self-consistent Sternheimer equation and localized basis sets

    Science.gov (United States)

    Hübener, Hannes; Pérez-Osorio, Miguel A.; Ordejón, Pablo; Giustino, Feliciano

    2012-06-01

    We develop a first-principles computational method for investigating the dielectric screening in extended systems using the self-consistent Sternheimer equation and localized nonorthogonal basis sets. Our approach does not require the explicit calculation of unoccupied electronic states, uses only two-center integrals, and has a theoretical scaling of order O(N3). We demonstrate this method by comparing our calculations for silicon, germanium, diamond, and LiCl with reference plane-wave calculations. We show that accuracy comparable to that of plane-wave calculations can be achieved via a systematic optimization of the basis set.

  1. Consistent evaluation of an ultrasound-guided surgical navigation system by utilizing an active validation platform

    Science.gov (United States)

    Kim, Younsu; Kim, Sungmin; Boctor, Emad M.

    2017-03-01

    An ultrasound image-guided needle tracking systems have been widely used due to their cost-effectiveness and nonionizing radiation properties. Various surgical navigation systems have been developed by utilizing state-of-the-art sensor technologies. However, ultrasound transmission beam thickness causes unfair initial evaluation conditions due to inconsistent placement of the target with respect to the ultrasound probe. This inconsistency also brings high uncertainty and results in large standard deviations for each measurement when we compare accuracy with and without the guidance. To resolve this problem, we designed a complete evaluation platform by utilizing our mid-plane detection and time of flight measurement systems. The evaluating system uses a PZT element target and an ultrasound transmitting needle. In this paper, we evaluated an optical tracker-based surgical ultrasound-guided navigation system whereby the optical tracker tracks marker frames attached on the ultrasound probe and the needle. We performed ten needle trials of guidance experiment with a mid-plane adjustment algorithm and with a B-mode segmentation method. With the midplane adjustment, the result showed a mean error of 1.62+/-0.72mm. The mean error increased to 3.58+/-2.07mm without the mid-plane adjustment. Our evaluation system can reduce the effect of the beam-thickness problem, and measure ultrasound image-guided technologies consistently with a minimal standard deviation. Using our novel evaluation system, ultrasound image-guided technologies can be compared under equal initial conditions. Therefore, the error can be evaluated more accurately, and the system provides better analysis on the error sources such as ultrasound beam thickness.

  2. General second order complete active space self-consistent-field solver for large-scale systems

    CERN Document Server

    Sun, Qiming

    2016-01-01

    One challenge of the complete active space self-consistent field (CASSCF) program is to solve the transition metal complexes which are typically medium or large-size molecular systems with large active space. We present an AO-driven second order CASSCF solver to efficiently handle systems which have a large number of AO functions and many active orbitals. This solver allows user to replace the active space Full CI solver with any multiconfigurational solver without breaking the quadratic convergence feature. We demonstrate the capability of the CASSCF solver with the study of Fe(ii)-porphine ground state using DMRG-CASSCF method for 22 electrons in 27 active orbitals and 3000 basis functions.

  3. Consistency from the perspective of an experimental systems approach to the sciences and their epistemic objects

    Directory of Open Access Journals (Sweden)

    Hans-Jörg Rheinberger

    2011-06-01

    Full Text Available It is generally accepted that the development of the modern sciences is rooted in experiment. Yet for a long time, experimentation did not occupy a prominent role, neither in philosophy nor in history of science. With the 'practical turn' in studying the sciences and their history, this has begun to change. This paper is concerned with systems and cultures of experimentation and the consistencies that are generated within such systems and cultures. The first part of the paper exposes the forms of historical and structural coherence that characterize the experimental exploration of epistemic objects. In the second part, a particular experimental culture in the life sciences is briefly described as an example. A survey will be given of what it means and what it takes to analyze biological functions in the test tube.

  4. Smart HVAC Control in IoT: Energy Consumption Minimization with User Comfort Constraints

    Science.gov (United States)

    Verikoukis, Christos

    2014-01-01

    Smart grid is one of the main applications of the Internet of Things (IoT) paradigm. Within this context, this paper addresses the efficient energy consumption management of heating, ventilation, and air conditioning (HVAC) systems in smart grids with variable energy price. To that end, first, we propose an energy scheduling method that minimizes the energy consumption cost for a particular time interval, taking into account the energy price and a set of comfort constraints, that is, a range of temperatures according to user's preferences for a given room. Then, we propose an energy scheduler where the user may select to relax the temperature constraints to save more energy. Moreover, thanks to the IoT paradigm, the user may interact remotely with the HVAC control system. In particular, the user may decide remotely the temperature of comfort, while the temperature and energy consumption information is sent through Internet and displayed at the end user's device. The proposed algorithms have been implemented in a real testbed, highlighting the potential gains that can be achieved in terms of both energy and cost. PMID:25054163

  5. Smart HVAC control in IoT: energy consumption minimization with user comfort constraints.

    Science.gov (United States)

    Serra, Jordi; Pubill, David; Antonopoulos, Angelos; Verikoukis, Christos

    2014-01-01

    Smart grid is one of the main applications of the Internet of Things (IoT) paradigm. Within this context, this paper addresses the efficient energy consumption management of heating, ventilation, and air conditioning (HVAC) systems in smart grids with variable energy price. To that end, first, we propose an energy scheduling method that minimizes the energy consumption cost for a particular time interval, taking into account the energy price and a set of comfort constraints, that is, a range of temperatures according to user's preferences for a given room. Then, we propose an energy scheduler where the user may select to relax the temperature constraints to save more energy. Moreover, thanks to the IoT paradigm, the user may interact remotely with the HVAC control system. In particular, the user may decide remotely the temperature of comfort, while the temperature and energy consumption information is sent through Internet and displayed at the end user's device. The proposed algorithms have been implemented in a real testbed, highlighting the potential gains that can be achieved in terms of both energy and cost.

  6. Self-consistent theory of finite Fermi systems and Skyrme–Hartree–Fock method

    Energy Technology Data Exchange (ETDEWEB)

    Saperstein, E. E., E-mail: saper@mbslab.kiae.ru; Tolokonnikov, S. V. [National Research Center Kurchatov Institute (Russian Federation)

    2016-11-15

    Recent results obtained on the basis of the self-consistent theory of finite Fermi systems by employing the energy density functional proposed by Fayans and his coauthors are surveyed. These results are compared with the predictions of Skyrme–Hartree–Fock theory involving several popular versions of the Skyrme energy density functional. Spherical nuclei are predominantly considered. The charge radii of even and odd nuclei and features of low-lying 2{sup +} excitations in semimagic nuclei are discussed briefly. The single-particle energies ofmagic nuclei are examined inmore detail with allowance for corrections to mean-field theory that are induced by particle coupling to low-lying collective surface excitations (phonons). The importance of taking into account, in this problem, nonpole (tadpole) diagrams, which are usually disregarded, is emphasized. The spectroscopic factors of magic and semimagic nuclei are also considered. In this problem, only the surface term stemming from the energy dependence induced in the mass operator by the exchange of surface phonons is usually taken into account. The volume contribution associated with the energy dependence initially present in the mass operator within the self-consistent theory of finite Fermi systems because of the exchange of high-lying particle–hole excitations is also included in the spectroscopic factor. The results of the first studies that employed the Fayans energy density functional for deformed nuclei are also presented.

  7. Demand response-enabled model predictive HVAC load control in buildings using real-time electricity pricing

    Science.gov (United States)

    Avci, Mesut

    A practical cost and energy efficient model predictive control (MPC) strategy is proposed for HVAC load control under dynamic real-time electricity pricing. The MPC strategy is built based on a proposed model that jointly minimizes the total energy consumption and hence, cost of electricity for the user, and the deviation of the inside temperature from the consumer's preference. An algorithm that assigns temperature set-points (reference temperatures) to price ranges based on the consumer's discomfort tolerance index is developed. A practical parameter prediction model is also designed for mapping between the HVAC load and the inside temperature. The prediction model and the produced temperature set-points are integrated as inputs into the MPC controller, which is then used to generate signal actions for the AC unit. To investigate and demonstrate the effectiveness of the proposed approach, a simulation based experimental analysis is presented using real-life pricing data. An actual prototype for the proposed HVAC load control strategy is then built and a series of prototype experiments are conducted similar to the simulation studies. The experiments reveal that the MPC strategy can lead to significant reductions in overall energy consumption and cost savings for the consumer. Results suggest that by providing an efficient response strategy for the consumers, the proposed MPC strategy can enable the utility providers to adopt efficient demand management policies using real-time pricing. Finally, a cost-benefit analysis is performed to display the economic feasibility of implementing such a controller as part of a building energy management system, and the payback period is identified considering cost of prototype build and cost savings to help the adoption of this controller in the building HVAC control industry.

  8. Electronic Properties of Polarizable Systems with Self-Consistent Interatomic van der Waals Density Functional

    Science.gov (United States)

    Ferri, Nicola; Distasio, Robert A., Jr.; Ambrosetti, Alberto; Car, Roberto; Scheffler, Matthias; Tkatchenko, Alexandre

    2015-03-01

    Ubiquitous long-range van der Waals (vdW) interactions play a fundamental role in the structure and stability of a wide range of systems. Within the DFT framework, the vdW energy represents a crucial, but tiny part of the total energy, hence its influence on the electronic density, n (r) , and electronic properties is typically assumed to be rather small. Here, we address this question via a fully self-consistent (SC) implementation of the interatomic Tkatchenko-Scheffler vdW functional and its extension to surfaces. Self-consistency leads to large changes in the binding energies and electrostatic moments of highly polarizable alkali metal dimers. For some metal surfaces, vdW interactions increase dipole moments and induce non-trivial charge rearrangements, leading to visible changes in the metal workfunctions. Similar behavior is observed for molecules adsorbed on metals. Our study reveals a non-trivial connection between electrostatics and long-range electron correlation effects.

  9. Self-consistent second-order Green’s function perturbation theory for periodic systems

    Energy Technology Data Exchange (ETDEWEB)

    Rusakov, Alexander A., E-mail: rusakov@umich.edu; Zgid, Dominika [Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2016-02-07

    Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green’s function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear as promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green’s function (GF2) method, where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in k-space are the key components of a computationally feasible algorithm. We apply this technique to the one-dimensional hydrogen lattice — a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases.

  10. Integrating Agents into a Collaborative Knowledge-based System for Business Rules Consistency Management

    Directory of Open Access Journals (Sweden)

    Nawal Sad Houari

    2016-12-01

    Full Text Available Capitalization and reuse of expert knowledge are very important for the survival of an enterprise. This paper presents a collaborative approach that utilizes domain ontology and agents. Thanks to our knowledge formalizing process, we give to domain expert an opportunity to store different forms of retrieved knowledge from experiences, design rules, business rules, decision processes, etc. The ontology is built to support business rules management. The global architecture is mainly composed of agents such as Expert agent, Evaluator agent, Translator agent, Security agent and Supervisor agent. The Evaluator agent is at the heart of our functional architecture, its role is to detect the problems that may arise in the consistency management module and provides a solution to these problems in order to validate the accuracy of business rules. In addition, a Security agent is defined to handle both security aspects in rules modeling and multi-agent system. The proposed approach is different from the others in terms of the number of rule’s inconsistencies which are detected and treated like contradiction, redundancy, invalid rules, domain violation and rules never applicable, the collaboration that is initiated among business experts and the guarantee of security of the business rules and all the agents which constitute our system. The developed collaborative system is applied in an industrial case study.C

  11. Subdiffusion-absorption process in a system consisting of two different media

    Science.gov (United States)

    Kosztołowicz, Tadeusz

    2017-02-01

    Subdiffusion with reaction A +B →B is considered in a system which consists of two homogeneous media joined together; the A particles are mobile, whereas B are static. Subdiffusion and reaction parameters, which are assumed to be independent of time and space variables, can be different in both media. Particles A move freely across the border between the media. In each part of the system, the process is described by the subdiffusion-reaction equations with fractional time derivative. By means of the method presented in this paper, we derive both the fundamental solutions (the Green's functions) P(x, t) to the subdiffusion-reaction equations and the boundary conditions at the border between the media. One of the conditions demands the continuity of a flux and the other one contains the Riemann-Liouville fractional time derivatives ∂α1P (0+,t ) /∂tα1 =(D1/D2 ) ∂α2P (0-,t ) /∂tα2 , where the subdiffusion parameters α1, D1 and α2, D2 are defined in the regions x 0 , respectively.

  12. Subdiffusion-absorption process in a system consisting of two different media.

    Science.gov (United States)

    Kosztołowicz, Tadeusz

    2017-02-28

    Subdiffusion with reaction A+B→B is considered in a system which consists of two homogeneous media joined together; the A particles are mobile, whereas B are static. Subdiffusion and reaction parameters, which are assumed to be independent of time and space variables, can be different in both media. Particles A move freely across the border between the media. In each part of the system, the process is described by the subdiffusion-reaction equations with fractional time derivative. By means of the method presented in this paper, we derive both the fundamental solutions (the Green's functions) P(x, t) to the subdiffusion-reaction equations and the boundary conditions at the border between the media. One of the conditions demands the continuity of a flux and the other one contains the Riemann-Liouville fractional time derivatives ∂(α1) P(0(+),t)/∂t(α1) =(D1/D2)∂(α2) P(0(-),t)/∂t(α2) , where the subdiffusion parameters α1, D1 and α2, D2 are defined in the regions x0, respectively.

  13. Self-consistent approach to the description of relaxation processes in classical multiparticle systems

    Science.gov (United States)

    Mokshin, A. V.

    2015-04-01

    The concept of time correlation functions is a very convenient theoretical tool in describing relaxation processes in multiparticle systems because, on one hand, correlation functions are directly related to experimentally measured quantities (for example, intensities in spectroscopic studies and kinetic coefficients via the Kubo-Green relation) and, on the other hand, the concept is also applicable beyond the equilibrium case. We show that the formalism of memory functions and the method of recurrence relations allow formulating a self-consistent approach for describing relaxation processes in classical multiparticle systems without needing a priori approximations of time correlation functions by model dependences and with the satisfaction of sum rules and other physical conditions guaranteed. We also demonstrate that the approach can be used to treat the simplest relaxation scenarios and to develop microscopic theories of transport phenomena in liquids, the propagation of density fluctuations in equilibrium simple liquids, and structure relaxation in supercooled liquids. This approach generalizes the mode-coupling approximation in the Götze-Leutheusser realization and the Yulmetyev-Shurygin correlation approximations.

  14. Wire position system to consistently measure and record the location change of girders following ground changes

    Science.gov (United States)

    Choi, H. J.; Lee, S. B.; Lee, H. G.; Y Back, S.; Kim, S. H.; Kang, H. S.

    2017-07-01

    Several parts that comprise the large scientific device should be installed and operated at the accurate three-dimensional location coordinates (X, Y, and Z) where they should be subjected to survey and alignment. The location of the aligned parts should not be changed in order to ensure that the electron beam parameters (Energy 10 GeV, Charge 200 pC, and Bunch Length 60 fs, Emittance X/Y 0.481 μm/0.256 μm) of PAL-XFEL (X-ray Free Electron Laser of the Pohang Accelerator Laboratory) remain stable and can be operated without any problems. As time goes by, however, the ground goes through uplift and subsidence, which consequently deforms building floors. The deformation of the ground and buildings changes the location of several devices including magnets and RF accelerator tubes, which eventually leads to alignment errors (∆X, ∆Y, and ∆Z). Once alignment errors occur with regard to these parts, the electron beam deviates from its course and beam parameters change accordingly. PAL-XFEL has installed the Hydrostatic Leveling System (HLS) to measure and record the vertical change of buildings and ground consistently and systematically and the Wire Position System (WPS) to measure the two dimensional changes of girders. This paper is designed to introduce the operating principle and design concept of WPS and discuss the current situation regarding installation and operation.

  15. Steps towards a consistent Climate Forecast System Reanalysis wave hindcast (1979-2016)

    Science.gov (United States)

    Stopa, Justin E.; Ardhuin, Fabrice; Huchet, Marion; Accensi, Mickael

    2017-04-01

    Surface gravity waves are being increasingly recognized as playing an important role within the climate system. Wave hindcasts and reanalysis products of long time series (>30 years) have been instrumental in understanding and describing the wave climate for the past several decades and have allowed a better understanding of extreme waves and inter-annual variability. Wave hindcasts have the advantage of covering the oceans in higher space-time resolution than possible with conventional observations from satellites and buoys. Wave reanalysis systems like ECWMF's ERA-Interim directly included a wave model that is coupled to the ocean and atmosphere, otherwise reanalysis wind fields are used to drive a wave model to reproduce the wave field in long time series. The ERA Interim dataset is consistent in time, but cannot adequately resolve extreme waves. On the other hand, the NCEP Climate Forecast System (CFSR) wind field better resolves the extreme wind speeds, but suffers from discontinuous features in time which are due to the quantity and quality of the remote sensing data incorporated into the product. Therefore, a consistent hindcast that resolves the extreme waves still alludes us limiting our understanding of the wave climate. In this study, we systematically correct the CFSR wind field to reproduce a homogeneous wave field in time. To verify the homogeneity of our hindcast we compute error metrics on a monthly basis using the observations from a merged altimeter wave database which has been calibrated and quality controlled from 1985-2016. Before 1985 only few wave observations exist and are limited to a select number of wave buoys mostly in the North Hemisphere. Therefore we supplement our wave observations with seismic data which responds to nonlinear wave interactions created by opposing waves with nearly equal wavenumbers. Within the CFSR wave hindcast, we find both spatial and temporal discontinuities in the error metrics. The Southern Hemisphere often

  16. Practical Guide to HVAC for Schools.

    Science.gov (United States)

    ASHRAE Journal, 1998

    1998-01-01

    Features six articles on heating, ventilation, and air-conditioning systems for schools. Examines how to avoid air temperature complaints when choosing a system; special system features; engineers, indoor air quality, and schools; mechanical systems noise in classrooms; operation and management issues related to design; and details on bids and…

  17. Progress on Developing Consistent Earth System Data Records for the Global Terrestrial Water Cycle

    Science.gov (United States)

    Wood, E. F.; Lettenmaier, D. P.; Houser, P.; Pinker, R. T.; Kummerow, C. D.; Pan, M.; Gao, H.; Sahoo, A. K.

    2009-12-01

    Consistent, long-term Earth System Data Records (ESDRs) for the terrestrial water cycle are needed to provide a basis for estimating the mean state and variability of the land surface water cycle for the major global river basins and the global terrestrial hydrosphere. For consistency, the ESDRs for each component must be done within a framework that assures such consistency. In this project that started one year ago, five institutions are collaborating to jointly develop the terrestrial water cycle ESRDs, with the goal of producing ESDRs at a spatial resolution of 0.5 degrees (latitude-longitude) for the period 1950 to near-present. The strategy for the ESDRs is to (i) retrieve through state-of-the-art remote sensing algorithms surface radiation and water cycle variables applied to the satellite records that extend as far back as possible, which in most cases is the early 1980’s; (ii) estimate water cycle components through off-line land surface model integrations that will extend back to 1950; and (iii) to merge the remote sensing estimates with the land surface estimates using advanced data assimilation techniques. Over the last year the project has completed the Algorithm Theoretical Basis Documents (ATBDs), which provide documentation for all algorithms that will generate the data products. The production of the ESDRs also started for (1) surface meteorology (precipitation, air temperature, humidity and wind), (2) surface downward radiation (solar and longwave) and (3) derived and/or assimilated fluxes and storages such as surface soil moisture storage, total basin water storage, snow water equivalent, storage in large lakes, reservoirs, and wetlands, evapotranspiration, and surface runoff. Where our products overlap other Measures ESDR products (e.g. snow extent), we plan to work with those project to assure overall consistency. On the modeling part, a global surface meteorology data set that covers 1900-2006 has been established by merging satellite, in

  18. Cell Communication in a Coculture System Consisting of Outgrowth Endothelial Cells and Primary Osteoblasts

    Directory of Open Access Journals (Sweden)

    David Paul Eric Herzog

    2014-01-01

    Full Text Available Bone tissue is a highly vascularized and dynamic system with a complex construction. In order to develop a construct for implant purposes in bone tissue engineering, a proper understanding of the complex dependencies between different cells and cell types would provide further insight into the highly regulated processes during bone repair, namely, angiogenesis and osteogenesis, and might result in sufficiently equipped constructs to be beneficial to patients and thereby accomplish their task. This study is based on an in vitro coculture model consisting of outgrowth endothelial cells and primary osteoblasts and is currently being used in different studies of bone repair processes with special regard to angiogenesis and osteogenesis. Coculture systems of OECs and pOBs positively influence the angiogenic potential of endothelial cells by inducing the formation of angiogenic structures in long-term cultures. Although many studies have focused on cell communication, there are still numerous aspects which remain poorly understood. Therefore, the aim of this study is to investigate certain growth factors and cell communication molecules that are important during bone repair processes. Selected growth factors like VEGF, angiopoietins, BMPs, and IGFs were investigated during angiogenesis and osteogenesis and their expression in the cultures was observed and compared after one and four weeks of cultivation. In addition, to gain a better understanding on the origin of different growth factors, both direct and indirect coculture strategies were employed. Another important focus of this study was to investigate the role of “gap junctions,” small protein pores which connect adjacent cells. With these bridges cells are able to exchange signal molecules, growth factors, and other important mediators. It could be shown that connexins, the gap junction proteins, were located around cell nuclei, where they await their transport to the cell membrane. In

  19. Consistency analysis for the performance of planar detector systems used in advanced radiotherapy

    Directory of Open Access Journals (Sweden)

    Kanan Jassal

    2015-03-01

    Full Text Available Purpose: To evaluate the performance linked to the consistency of a-Si EPID and ion-chamber array detectors for dose verification in advanced radiotherapy.Methods: Planar measurements were made for 250 patients using an array of ion chamber and a-Si EPID. For pre-treatment verification, the plans were generated on the phantom for re-calculation of doses. The γ-evaluation method with the criteria: dose-difference (DD ≤ 3% and distance-to-agreement (DTA ≤ 3 mm was used for the comparison of measurements. Also, the central axis (CAX doses were measured using 0.125cc ion chamber and were compared with the central chamber of array and central pixel correlated dose value from EPID image. Two types of statistical approaches were applied for the analysis. Conventional statistics used analysis of variance (ANOVA and unpaired t-test to evaluate the performance of the detectors. And statistical process control (SPC was utilized to study the statistical variation for the measured data. Control charts (CC based on an average , standard deviation ( and exponentially weighted moving averages (EWMA were prepared. The capability index (Cpm was determined as an indicator for the performance consistency of the two systems.Results: Array and EPID measurements had the average gamma pass rates as 99.9% ± 0.15% and 98.9% ± 1.06% respectively. For the point doses, the 0.125cc chamber results were within 2.1% ± 0.5% of the central chamber of the array. Similarly, CAX doses from EPID and chamber matched within 1.5% ± 0.3%. The control charts showed that both the detectors were performing optimally and all the data points were within ± 5%. EWMA charts revealed that both the detectors had a slow drift along the mean of the processes but was found well within ± 3%. Further, higher Cpm values for EPID demonstrate its higher efficiency for radiotherapy techniques.Conclusion: The performances of both the detectors were seen to be of high quality irrespective of the

  20. Investigation of IAQ-Relevant Surface Chemistry and Emissions on HVAC Filter Materials

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Fisk, William J.

    2010-02-01

    Chemical reactions involving ozone of outdoor origin and indoor materials are known to be significant sources of formaldehyde and other irritant gas-phase oxidation products in the indoor environment. HVAC filters are exposed to particularly high ozone concentrations--close to outdoor levels. In this study, we investigated chemical processes taking place on the surface of filters that included fiberglass, polyester, cotton/polyester blend and synthetic (e.g., polyolefin) filter media. Ozone reactions were studied on unused filter media, and on filters that were deployed for 3 months in two different locations: at the Lawrence Berkeley National Laboratory and at the Port of Oakland. Specimens from each filter were exposed to ozone under controlled conditions in a laboratory flow tube at a constant flow of dry or humidified air (50percent relative humidity). Ozone was generated with a UV source upstream of the flow tube, and monitored using a photometric detector. Ozone breakthrough curves were recorded for each sample exposed to ~;;150 ppbv O3 for periods of ~;;1000 min, from which we estimated their uptake rate. Most experiments were performed at 1.3 L/min (corresponding to a face velocity of 0.013 m/s), except for a few tests performed at a higher airflow rate, to obtain a face velocity of 0.093 m/s, slightly closer to HVAC operation conditions. Formaldehyde and acetaldehyde, two oxidation byproducts, were collected downstream of the filter and quantified. Emissions of these volatile aldehydes were consistently higher under humidified air than under dry conditions, at which levels were near the limit of detection. Our results confirm that there are significant reactions of ozone as air containing ozone flows through HVAC filters, particularly when the filters are loaded with particles and the air is humidified. The amount of ozone reacted was not clearly related to the types of filter media, e.g., fiberglass versus synthetic. Specific fiberglass filters that were

  1. Assessment of the Degree of Consistency of the System of Fuzzy Rules

    Directory of Open Access Journals (Sweden)

    Pospelova Lyudmila Yakovlevna

    2013-12-01

    Full Text Available The article analyses recent achievements and publications and shows that difficulties of explaining the nature of fuzziness and equivocation arise in socio-economic models that use the traditional paradigm of classical rationalism (computational, agent and econometric models. The accumulated collective experience of development of optimal models confirms prospectiveness of application of the fuzzy set approach in modelling the society. The article justifies the necessity of study of the nature of inconsistency in fuzzy knowledge bases both on the generalised ontology level and on pragmatic functional level of the logical inference. The article offers the method of search for logical and conceptual contradictions in the form of a combination of the abduction and modus ponens. It discusses the key issue of the proposed method: what properties should have the membership function of the secondary fuzzy set, which describes in fuzzy inference models such a resulting state of the object of management, which combines empirically incompatible properties with high probability. The degree of membership of the object of management in several incompatible classes with respect to the fuzzy output variable is the degree of fuzziness of the “Intersection of all results of the fuzzy inference of the set, applied at some input of rules, is an empty set” statement. The article describes an algorithm of assessment of the degree of consistency. It provides an example of the step-by-step detection of contradictions in statistical fuzzy knowledge bases at the pragmatic functional level of the logical output. The obtained results of testing in the form of sets of incompatible facts, output chains, sets of non-crossing intervals and computed degrees of inconsistency allow experts timely elimination of inadmissible contradictions and, at the same time, increase of quality of recommendations and assessment of fuzzy expert systems.

  2. Adjoint-consistent formulations of slip models for coupled electroosmotic flow systems

    KAUST Repository

    Garg, Vikram V

    2014-09-27

    Background Models based on the Helmholtz `slip\\' approximation are often used for the simulation of electroosmotic flows. The objectives of this paper are to construct adjoint-consistent formulations of such models, and to develop adjoint-based numerical tools for adaptive mesh refinement and parameter sensitivity analysis. Methods We show that the direct formulation of the `slip\\' model is adjoint inconsistent, and leads to an ill-posed adjoint problem. We propose a modified formulation of the coupled `slip\\' model, which is shown to be well-posed, and therefore automatically adjoint-consistent. Results Numerical examples are presented to illustrate the computation and use of the adjoint solution in two-dimensional microfluidics problems. Conclusions An adjoint-consistent formulation for Helmholtz `slip\\' models of electroosmotic flows has been proposed. This formulation provides adjoint solutions that can be reliably used for mesh refinement and sensitivity analysis.

  3. What Indicates Competency in Systems Based Practice? An Analysis of Perspective Consistency among Healthcare Team Members

    Science.gov (United States)

    Graham, Mark J.; Naqvi, Zoon; Encandela, John A.; Bylund, Carma L.; Dean, Randa; Calero-Breckheimer, Ayxa; Schmidt, Hilary J.

    2009-01-01

    In many parts of the world the practice of medicine and medical education increasingly focus on providing patient care within context of the larger healthcare system. Our purpose is to solicit perceptions of all professional stakeholders (e.g. nurses) of the system regarding the U.S. ACGME competency Systems Based Practice to uncover the extent to…

  4. Solution Properties of Linear Descriptor (Singular Matrix Differential Systems of Higher Order with (Non- Consistent Initial Conditions

    Directory of Open Access Journals (Sweden)

    Athanasios A. Pantelous

    2010-01-01

    Full Text Available In some interesting applications in control and system theory, linear descriptor (singular matrix differential equations of higher order with time-invariant coefficients and (non- consistent initial conditions have been used. In this paper, we provide a study for the solution properties of a more general class of the Apostol-Kolodner-type equations with consistent and nonconsistent initial conditions.

  5. The Consistency between Human Raters and an Automated Essay Scoring System in Grading High School Students' English Writing

    Science.gov (United States)

    Tsai, Min-hsiu

    2012-01-01

    This study investigates the consistency between human raters and an automated essay scoring system in grading high school students' English compositions. A total of 923 essays from 23 classes of 12 senior high schools in Taiwan (Republic of China) were obtained and scored manually and electronically. The results show that the consistency between…

  6. Application of Computer Model to Estimate the Consistency of Air Conditioning Systems Engineering

    Directory of Open Access Journals (Sweden)

    Amal El-Berry

    2013-04-01

    Full Text Available Reliability engineering is utilized to predict the performance and optimization of the design and maintenance of air conditioning systems. There are a number of failures associated with the conditioning systems. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely are mainly due to a variety of problems with one or more components of an air conditioner or air conditioning system. To maintain the system forecasting for system failure rates are very important. The focus of this paper is the reliability of the air conditioning systems. The most common applied statistical distributions in reliability settings are the standard (2 parameter Weibull and Gamma distributions. Reliability estimations and predictions are used to evaluate, when the estimation of distributionsparameters is done. To estimate good operating condition in a building, the reliability of the air conditioning system that supplies conditioned air to the several companies’ departments is checked. This air conditioning system is divided into two systems, namely the main chilled water system and the ten air handling systems that serves the ten departments. In a chilled-water system the air conditioner cools water down to 40 - 45oF (4 - 7oC. The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed. Data analysis has been done with support a computer aided reliability software, with the application of the Weibull and Gamma distributions it is indicated that the reliability for the systems equal to 86.012% and 77.7% respectively . A comparison between the two important families of distribution functions, namely, the Weibull and Gamma families is studied. It is found that Weibull method has performed well for decision making .

  7. Joint HVAC transmission EMF environmental study

    Energy Technology Data Exchange (ETDEWEB)

    Stormshak, F.; Thompson, J. (Oregon State Univ., Corvallis, OR (United States))

    1992-05-01

    This document describes the rationale, procedures, and results of a carefully controlled study conducted to establish whether chronic exposure of female (ewe) Suffolk lambs to the environment of a 500-kV 60-Hz transmission line would affect various characteristics of growth, endocrine function, and reproductive development. This experiment used identical housing and management schemes for control and line-exposed ewes, thus minimizing these factors as contributors to between-group experimental error. Further, throughout the 10-month duration of this study, changes in electric and magnetic fields, audible noise, and weather conditions were monitored continuously by a computerized system. Such measurements provided the opportunity to identify any relationship between environmental factors and biological responses. Because of reports in the literature that electric and magnetic fields alter concentrations of melatonin in laboratory animals, the primary objective of this study was to ascertain whether a similar effect occurs in lambs exposed to a 500-kV a-c line in a natural setting. In addition, onset of puberty, changes in body weight, wool growth, and behavior were monitored. To determine whether the environment of a 500-kV line caused stress in the study animals, serum levels of cortisol were measured. The study was conducted at Bonneville Power Administration's Ostrander Substation near Estacada, Oregon.

  8. Structure of the body-centered cubic phase of lipid systems does not consist of indefinitely long straight rods

    OpenAIRE

    Luzzati, Vittorio; Tardieu, Annette; Gulik-Krzywicki, Tadeusz

    1981-01-01

    The observed intensities of the reflections from the body-centered cubic phase of lipid systems are shown to be incompatible with a recently reported model consisting of straight, indefinitely long rods.

  9. The NYC native air sampling pilot project: using HVAC filter data for urban biological incident characterization.

    Science.gov (United States)

    Ackelsberg, Joel; Leykam, Frederic M; Hazi, Yair; Madsen, Larry C; West, Todd H; Faltesek, Anthony; Henderson, Gavin D; Henderson, Christopher L; Leighton, Terrance

    2011-09-01

    Native air sampling (NAS) is distinguished from dedicated air sampling (DAS) devices (eg, BioWatch) that are deployed to detect aerosol disseminations of biological threat agents. NAS uses filter samples from heating, ventilation, and air conditioning (HVAC) systems in commercial properties for environmental sampling after DAS detection of biological threat agent incidents. It represents an untapped, scientifically sound, efficient, widely distributed, and comparably inexpensive resource for postevent environmental sampling. Calculations predict that postevent NAS would be more efficient than environmental surface sampling by orders of magnitude. HVAC filter samples could be collected from pre-identified surrounding NAS facilities to corroborate the DAS alarm and delineate the path taken by the bioaerosol plume. The New York City (NYC) Native Air Sampling Pilot Project explored whether native air sampling would be acceptable to private sector stakeholders and could be implemented successfully in NYC. Building trade associations facilitated outreach to and discussions with property owners and managers, who expedited contact with building managers of candidate NAS properties that they managed or owned. Nominal NAS building requirements were determined; procedures to identify and evaluate candidate NAS facilities were developed; data collection tools and other resources were designed and used to expedite candidate NAS building selection and evaluation in Manhattan; and exemplar environmental sampling playbooks for emergency responders were completed. In this sample, modern buildings with single or few corporate tenants were the best NAS candidate facilities. The Pilot Project successfully demonstrated that in one urban setting a native air sampling strategy could be implemented with effective public-private collaboration.

  10. The decrease of consistence probability: at the crossroad of catastrophic transition of a biological system

    National Research Council Canada - National Science Library

    Chen, Pei; Li, Yongjun

    2016-01-01

    ... the serious deterioration, not only because of the high complexity of the biological system, but there may be few clues and apparent changes appearing until the catastrophic critical transition occurs...

  11. Construction of an integrated enzyme system consisting azoreductase and glucose 1-dehydrogenase for dye removal.

    Science.gov (United States)

    Yang, Yuyi; Wei, Buqing; Zhao, Yuhua; Wang, Jun

    2013-02-01

    Azo dyes are toxic and carcinogenic and are often present in industrial effluents. In this research, azoreductase and glucose 1-dehydrogenase were coupled for both continuous generation of the cofactor NADH and azo dye removal. The results show that 85% maximum relative activity of azoreductase in an integrated enzyme system was obtained at the conditions: 1U azoreductase:10U glucose 1-dehydrogenase, 250mM glucose, 1.0mM NAD(+) and 150μM methyl red. Sensitivity analysis of the factors in the enzyme system affecting dye removal examined by an artificial neural network model shows that the relative importance of enzyme ratio between azoreductase and glucose 1-dehydrogenase was 22%, followed by dye concentration (27%), NAD(+) concentration (23%) and glucose concentration (22%), indicating none of the variables could be ignored in the enzyme system. Batch results show that the enzyme system has application potential for dye removal.

  12. A rotating inertial navigation system with the rotating axis error compensation consisting of fiber optic gyros

    Institute of Scientific and Technical Information of China (English)

    ZHA Feng; HU Bai-qing; QIN Fang-jun; LUO Yin-bo

    2012-01-01

    An effective and flexible rotation and compensation scheme is designed to improve the accuracy of rotating inertial navigation system (RINS).The accuracy of single-axial RINS is limited by the errors on the rotating axis.A novel inertial measurement unit (IMU) scheme with error compensation for the rotating axis of fiber optic gyros (FOG) RINS is presented.In the scheme,two couples of inertial sensors with similar error characteristics are mounted oppositely on the rotating axes to compensate the sensors error.Without any change for the rotation cycle,this scheme improves the system's precision and reliability,and also offers the redundancy for the system.The results of 36 h navigation simulation prove that the accuracy of the system is improved notably compared with normal strapdown INS,besides the heading accuracy is increased by 3 times compared with single-axial RINS,and the position accuracy is improved by 1 order of magnitude.

  13. Building America Expert Meeting Report: Transitioning Traditional HVAC Contractors to Whole House Performance Contractors

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, A.

    2011-10-01

    This report outlines findings resulting from a U.S. Department of Energy Building America expert meeting to determine how HVAC companies can transition from a traditional contractor status to a service provider for whole house energy upgrade contracting. IBACOS has embarked upon a research effort under the Building America Program to understand business impacts and change management strategies for HVAC companies. HVAC companies can implement these strategies in order to quickly transition from a 'traditional' heating and cooling contractor to a service provider for whole house energy upgrade contracting. Due to HVAC service contracts, which allow repeat interaction with homeowners, HVAC companies are ideally positioned in the marketplace to resolve homeowner comfort issues through whole house energy upgrades. There are essentially two primary ways to define the routes of transition for an HVAC contractor taking on whole house performance contracting: (1) Sub-contracting out the shell repair/upgrade work; and (2) Integrating the shell repair/upgrade work into their existing business. IBACOS held an Expert Meeting on the topic of Transitioning Traditional HVAC Contractors to Whole House Performance Contractors on March 29, 2011 in San Francisco, CA. The major objectives of the meeting were to: Review and validate the general business models for traditional HVAC companies and whole house energy upgrade companies Review preliminary findings on the differences between the structure of traditional HVAC Companies and whole house energy upgrade companies Seek industry input on how to structure information so it is relevant and useful for traditional HVAC contractors who are transitioning to becoming whole house energy upgrade contractors Seven industry experts identified by IBACOS participated in the session along with one representative from the National Renewable Energy Laboratory (NREL). The objective of the meeting was to validate the general operational

  14. An analytical system enabling consistent and long-term measurement of atmospheric dimethyl sulfide

    Science.gov (United States)

    Jang, Sehyun; Park, Ki-Tae; Lee, Kitack; Suh, Young-Sang

    2016-06-01

    We describe here an analytical system capable of continuous measurement of atmospheric dimethylsulfide (DMS) at pptv levels. The system uses customized devices for detector calibration and for DMS trapping and desorption that are controlled using a data acquisition system (based on Visual Basic 6.0/C 6.0) designed to maximize the efficiency of DMS analysis in a highly sensitive pulsed flame photometric detector housed in a gas chromatograph. The fully integrated system, which can sample approximately 6 L of air during a 1-hr sampling, was used to measure the atmospheric DMS mixing ratio over the Atlantic sector of the Arctic Ocean over 3 full annual growth cycles of phytoplankton in 2010, 2014, and 2015, with minimal routine maintenance and interruptions. During the field campaigns, the measured atmospheric DMS mixing ratio varied over a considerable range, from <1.5 pptv to maximum levels of 298 pptv in 2010, 82 pptv in 2014, and 429 pptv in 2015. The operational period covering the 3 full annual growth cycles of phytoplankton showed that the system is suitable for uninterrupted measurement of atmospheric DMS mixing ratios in extreme environments. Moreover, the findings obtained using the system showed it to be useful in identifying ocean DMS source regions and changes in source strength.

  15. 公共建筑项目中暖通空调专业的绿色设计%The Green Design of HVAC in Public Building Projects

    Institute of Scientific and Technical Information of China (English)

    李林

    2012-01-01

    室内环境质量、节能与能源利用与暖通空调专业紧密相关的。在设计阶段,室内设计参数决定着室内环境质量,而围护结构的热工性能和暖通空调系统设计直接决定着绿色建筑中节能与能源利用。本文对绿色建筑项目中的暖通空调设计做了初步探讨,旨在为绿色建筑项目中的暖通空调设计提供一定的指导。在项目设计中,不仅需要选择节能型的设备、设计合理的系统形式,还需与建筑师共同探讨建筑围护结构的热工性能,同时还需根据项目所在地的情况做到因地制宜,切忌盲目使用可再生能源。%The quality of indoor environmental,energy conservation and energy use are closely related to HVAC.In the design phase,indoor environmental quality is determined by the design parameters,and the thermal performance of building envelope and HVAC system directly determines the design of energy-efficient and energy use in green buildings.In this paper,preliminary study has been discussed in the HVAC design for green building project to provide some design guidance in HVAC.In order to save real energy in HVAC design,energy-efficient HVAC equipment isn't only need to be chosen in projects,but also reasonable system design and the building envelope thermal performance with the architect should be considered.Meanwhile the use of renewable energy is needed to be based on the situation of project and the local conditions,renewable energy should not be ill-used.

  16. User dynamics in a Dutch cafeteria system Consistent choices, inconsistent participation

    NARCIS (Netherlands)

    van der Meer, Peter; van Veen, Kees

    2009-01-01

    Purpose - This paper aims to contribute to the empirical literature on cafeteria systems within employment relations by analysing employees' decisions on whether or not to participate, which employees chose what options and how the factors vary over time. Design/methodology/approach - The approach t

  17. HVAC concepts for the future; Klimatiseringsconcepten voor de toekomst

    Energy Technology Data Exchange (ETDEWEB)

    Verkerk-Evers, J.E.J.; Struck, C.; Hensen, J.L.M. [Technische Universiteit Eindhoven, Eindhoven (Netherlands); Van Herpen, R.A.P. [Adviesburo Nieman, Utrecht (Netherlands); Wijsman, A.J.Th.M.; Plokker, W. [VABI Software, Delft (Netherlands)

    2010-07-15

    HVAC installations, for example for office buildings, are in practice designed using computer simulations that rely on 40 year old weather data (1964-1965). This is already giving rise to comfort complaints in hot summer weather. A different approach to design is required if buildings are to continue performing well into the future. This problem was the subject of the graduation study reviewed in this article. [Dutch] Klimaatinstallaties in bijvoorbeeld kantoren worden in de praktijk ontworpen op basis van computersimulaties, waarbij gebruik wordt gemaakt van ruim 40 jaar oude weergegevens (1964-1965). In warme zomers zijn er nu al vaak comfortklachten. Om gebouwen te kunnen realiseren die ook in de toekomst goed blijven presteren is een andere benadering bij het ontwerpen nodig. Deze problematiek is het onderwerp geweest van een afstudeeronderzoek aan de Technische Universiteit Eindhoven, in samenwerking met Adviesburo Nieman en Vabi Software, dat in dit artikel wordt besproken.

  18. Decomposition of formaldehyde by EPD photocatalyst filters in HVAC

    Institute of Scientific and Technical Information of China (English)

    Chien-Chih Chen; Ching-Song Jwo; Tun-Ping Teng

    2011-01-01

    This study used electrophoretic deposition (EPD) to apply titanium oxide (TiO2) coating on stainless steel filters and investigated the effectiveness of photocatalytic oxidation of formaldehyde by TiO2 under various conditions of heating ventilation air conditioning (HVAC).The results showed photocatalytic efficiency could reach 35.59% at 21 ℃ and 36.39% at 26℃ with 7 photocatalyst filters and 5 UVC lamps,the overall efficiency of formaldehyde removal of 52.37% at 21 ℃,and 56.8% at 26℃.By all experimental data can be found that the temperature for the photocatalytic performance is not obvious in the range of this study.

  19. Reproduction of consistent pulse-waveform changes using a computational model of the cerebral circulatory system.

    Science.gov (United States)

    Connolly, Mark; He, Xing; Gonzalez, Nestor; Vespa, Paul; DiStefano, Joe; Hu, Xiao

    2014-03-01

    Due to the inaccessibility of the cranial vault, it is difficult to study cerebral blood flow dynamics directly. A mathematical model can be useful to study these dynamics. The model presented here is a novel combination of a one-dimensional fluid flow model representing the major vessels of the circle of Willis (CoW), with six individually parameterized auto-regulatory models of the distal vascular beds. This model has the unique ability to simulate high temporal resolution flow and velocity waveforms, amenable to pulse-waveform analysis, as well as sophisticated phenomena such as auto-regulation. Previous work with human patients has shown that vasodilation induced by CO2 inhalation causes 12 consistent pulse-waveform changes as measured by the morphological clustering and analysis of intracranial pressure algorithm. To validate this model, we simulated vasodilation and successfully reproduced 9 out of the 12 pulse-waveform changes. A subsequent sensitivity analysis found that these 12 pulse-waveform changes were most affected by the parameters associated with the shape of the smooth muscle tension response and vessel elasticity, providing insight into the physiological mechanisms responsible for observed changes in the pulse-waveform shape.

  20. Cosmological evolution and Solar System consistency of massive scalar-tensor gravity

    Science.gov (United States)

    de Pirey Saint Alby, Thibaut Arnoulx; Yunes, Nicolás

    2017-09-01

    The scalar-tensor theory of Damour and Esposito-Farèse recently gained some renewed interest because of its ability to suppress modifications to general relativity in the weak field, while introducing large corrections in the strong field of compact objects through a process called scalarization. A large sector of this theory that allows for scalarization, however, has been shown to be in conflict with Solar System observations when accounting for the cosmological evolution of the scalar field. We here study an extension of this theory by endowing the scalar field with a mass to determine whether this allows the theory to pass Solar System constraints upon cosmological evolution for a larger sector of coupling parameter space. We show that the cosmological scalar field goes first through a quiescent phase, similar to the behavior of a massless field, but then it enters an oscillatory phase, with an amplitude (and frequency) that decays (and grows) exponentially. We further show that after the field enters the oscillatory phase, its effective energy density and pressure are approximately those of dust, as expected from previous cosmological studies. Due to these oscillations, we show that the scalar field cannot be treated as static today on astrophysical scales, and so we use time-dependent perturbation theory to compute the scalar-field-induced modifications to Solar System observables. We find that these modifications are suppressed when the mass of the scalar field and the coupling parameter of the theory are in a wide range, allowing the theory to pass Solar System constraints, while in principle possibly still allowing for scalarization.

  1. 三峡左岸电站暖通空调系统设计与运行%HVAC system design and operation of Three Gorges Left Bank Power Station

    Institute of Scientific and Technical Information of China (English)

    张晓华

    2012-01-01

    Presents the design features of the two central air conditioning systems and one main ventilation system of the power station and analyses their operation. According to characteristics of the zones served, No. 1 central air conditioning system is designed as an open system and supplies air with spherical nozzles in large spaces; No. 2 central air conditioning system is designed as a closed system with double loop pipelines; and both of them are equipped with sufficient stand-up devices for guaranteeing the systems' reliability. The main ventilation system uses the low-temperature gallery for cooling and supplies the cold air to air-conditioned areas by three-stage cascade fans after two-stage filtering.%介绍了三峡左岸电站的2个集中空调系统和1个主通风系统的设计特点,并分析了其运行情况.根据所服务区域的特点,1#集中空调系统设计为开式系统,大空间采用球形喷口送风;2#集中空调系统设计为闭式系统,采用双循环管路;为保证系统的可靠性,均考虑了足够的备用设备.主通风系统利用低温廊道降温,送风经两次过滤,由三级风机接力送入空调区域.

  2. Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

    Science.gov (United States)

    Ohmacht, Martin

    2014-09-09

    In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

  3. Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

    Energy Technology Data Exchange (ETDEWEB)

    Ohmacht, Martin

    2017-08-15

    In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

  4. HVAC system design of liquid desiccant fresh air unit combined with ground-source heat pump%溶液调湿新风机组与地源热泵相结合的空调设计

    Institute of Scientific and Technical Information of China (English)

    张伟程; 滕汜颖

    2013-01-01

    以上海虹桥产业楼空调系统为例,介绍了溶液调湿新风机组与地源热泵系统的设计,重点介绍了干式末端设备、冷热源主机、地埋管系统、空调水系统及自控系统设计的要点.根据实际运行调试情况,对冷热源水系统、干式风机盘管、高温型地源热泵机组、免费冷热源板式换热器、地源热泵与冷水机组的运行策略及生活热水应用进行了经验总结.%Taking the Shanghai Hongqiao Industrial Building air conditioning system as example, presents the liquid desiccant fresh air unit and ground-source heat pump design. Highlights the design points of the dry terminal device, cold and heat source unit, ground buried pipe system, air conditioning water system and automatic control system. According to the actual operation and commissioning, summarizes experiences of designing the cold and heat sources water system, dry fan-coil unit, high temperature ground-source heat pump, free cold and heat sources plate heat exchanger, water chiller and ground-source heat pump operation strategy and domestic hot water supply.

  5. Reducing Friction and Wear of Tribological Systems through Hybrid Tribofilm Consisting of Coating and Lubricants

    Directory of Open Access Journals (Sweden)

    Shuichiro Yazawa

    2014-06-01

    Full Text Available The role of surface protective additives becomes vital when operating conditions become severe and moving components operate in a boundary lubrication regime. After protecting film is slowly removed by rubbing, it can regenerate through the tribochemical reaction of the additives at the contact. However, there are limitations about the regeneration of the protecting film when additives are totally consumed. On the other hand, there are a lot of hard coatings to protect the steel surface from wear. These can enable the functioning of tribological systems, even in adverse lubrication conditions. However, hard coatings usually make the friction coefficient higher, because of their high interfacial shear strength. Amongst hard coatings, diamond-like carbon (DLC is widely used, because of its relatively low friction and superior wear resistance. In practice, conventional lubricants that are essentially formulated for a steel/steel surface are still used for lubricating machine component surfaces provided with protective coatings, such as DLCs, despite the fact that the surface properties of coatings are quite different from those of steel. It is therefore important that the design of additive molecules and their interaction with coatings should be re-considered. The main aim of this paper is to discuss the DLC and the additive combination that enable tribofilm formation and effective lubrication of tribological systems.

  6. Building America Expert Meeting Report. Transitioning Traditional HVAC Contractors to Whole House Performance Contractors

    Energy Technology Data Exchange (ETDEWEB)

    Burdick, Arlan [IBACOS Inc., Pittsburgh, PA (United States)

    2011-10-01

    This expert meeting was hosted by the IBACOS Building America research team to determine how HVAC companies can transition from a traditional contractor status to a service provider for whole house energy upgrade contracting.

  7. Interface Consistency

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen

    1998-01-01

    This paper proposes that Interface Consistency is an important issue for the development of modular designs. Byproviding a precise specification of component interfaces it becomes possible to check that separately developedcomponents use a common interface in a coherent matter thus avoiding a very...... significant source of design errors. Awide range of interface specifications are possible, the simplest form is a syntactical check of parameter types.However, today it is possible to do more sophisticated forms involving semantic checks....

  8. Expert Meeting Report: HVAC Fault Detection, DIagnosis, and Repair/Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Springer, David [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

    2016-05-01

    The concept for the expert meeting described in this report was to bring together most of the stakeholders in the area of FDD, including academic researchers, manufacturers, educators, program managers and implementers, representatives of standards organizations, utilities, HVAC contractors, and home performance contractors to identify the major gaps and to develop ideas about what can be done to capitalize on the residential HVAC efficiency resource.

  9. Expert Meeting Report: HVAC Fault Detection, Diagnosis, and Repair/Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Springer, David [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States). Davis Energy Group

    2016-05-01

    The concept for the expert meeting described in this report was to bring together most of the stakeholders in the area of FDD, including academic researchers, manufacturers, educators, program managers and implementers, representatives of standards organizations, utilities, HVAC contractors, and home performance contractors to identify the major gaps and to develop ideas about what can be done to capitalize on the residential HVAC efficiency resource.

  10. Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency"

    Energy Technology Data Exchange (ETDEWEB)

    Buelow, Roger; Jenson, Chris; Kazenski, Keith

    2013-03-21

    DOE has enabled the use of coating materials using low cost application methods on light sources to positively affect the output of those sources. The coatings and light source combinations have shown increased lumen output of LED fixtures (1.5%-2.0%), LED arrays (1.4%) and LED powered remote phosphor systems Philips L-Prize lamp (0.9%). We have also demonstrated lifetime enhancements (3000 hrs vs 8000 hrs) and shifting to higher CRI (51 to 65) in metal halide high intensity discharge lamps with metal oxide coatings. The coatings on LEDs and LED products are significant as the market is moving increasingly more towards LED technology. Enhancements in LED performance are demonstrated in this work through the use of available materials and low cost application processes. EFOI used low refractive index fluoropolymers and low cost dipping processes for application of the material to surfaces related to light transmission of LEDs and LED products. Materials included Teflon AF, an amorphous fluorinated polymer and fluorinated acrylic monomers. The DOE SSL Roadmap sets goals for LED performance moving into the future. EFOI's coating technology is a means to shift the performance curve for LEDs. This is not limited to one type of LED, but is relevant across LED technologies. The metal halide work included the use of sol-gel solutions resulting in silicon dioxide and titanium dioxide coatings on the quartz substrates of the metal halide arc tubes. The coatings were applied using low cost dipping processes.

  11. Uncertainty analysis of practical structural health monitoring systems currently employed for tall buildings consisting of small number of sensors

    Science.gov (United States)

    Hirai, Kenta; Mita, Akira

    2016-04-01

    Because of social background, such as repeated large earthquakes and cheating in design and construction, structural health monitoring (SHM) systems are getting strong attention. The SHM systems are in a practical phase. An SHM system consisting of small number of sensors has been introduced to 6 tall buildings in Shinjuku area. Including them, there are 2 major issues in the SHM systems consisting of small number of sensors. First, optimal system number of sensors and the location are not well-defined. In the practice, system placement is determined based on rough prediction and experience. Second, there are some uncertainties in estimation results by the SHM systems. Thus, the purpose of this research is to provide useful information for increasing reliability of SHM system and to improve estimation results based on uncertainty analysis of the SHM systems. The important damage index used here is the inter-story drift angle. The uncertainty considered here are number of sensors, earthquake motion characteristics, noise in data, error between numerical model and real building, nonlinearity of parameter. Then I have analyzed influence of each factor to estimation accuracy. The analysis conducted here will help to decide sensor system design considering valance of cost and accuracy. Because of constraint on the number of sensors, estimation results by the SHM system has tendency to provide smaller values. To overcome this problem, a compensation algorithm was discussed and presented. The usefulness of this compensation method was demonstrated for 40 story S and RC building models with nonlinear response.

  12. Mutual Inductance Problem for a System Consisting of a Current Sheet and a Thin Metal Plate

    Science.gov (United States)

    Fulton, J. P.; Wincheski, B.; Nath, S.; Namkung, M.

    1993-01-01

    Rapid inspection of aircraft structures for flaws is of vital importance to the commercial and defense aircraft industry. In particular, inspecting thin aluminum structures for flaws is the focus of a large scale R&D effort in the nondestructive evaluation (NDE) community. Traditional eddy current methods used today are effective, but require long inspection times. New electromagnetic techniques which monitor the normal component of the magnetic field above a sample due to a sheet of current as the excitation, seem to be promising. This paper is an attempt to understand and analyze the magnetic field distribution due to a current sheet above an aluminum test sample. A simple theoretical model, coupled with a two dimensional finite element model (FEM) and experimental data will be presented in the next few sections. A current sheet above a conducting sample generates eddy currents in the material, while a sensor above the current sheet or in between the two plates monitors the normal component of the magnetic field. A rivet or a surface flaw near a rivet in an aircraft aluminum skin will disturb the magnetic field, which is imaged by the sensor. Initial results showed a strong dependence of the flaw induced normal magnetic field strength on the thickness and conductivity of the current-sheet that could not be accounted for by skin depth attenuation alone. It was believed that the eddy current imaging method explained the dependence of the thickness and conductivity of the flaw induced normal magnetic field. Further investigation, suggested the complexity associated with the mutual inductance of the system needed to be studied. The next section gives an analytical model to better understand the phenomenon.

  13. An ERP study of effects of regularity and consistency in delayed naming and lexicality judgment in a logographic writing system

    Directory of Open Access Journals (Sweden)

    Yen Na eYum

    2014-04-01

    Full Text Available Phonological access is an important component in theories and models of word reading. However, phonological regularity and consistency effects are not clearly separable in alphabetic writing systems. We investigated these effects in Chinese, where the two variables are operationally distinct. In this orthographic system, regularity is defined as the congruence between the pronunciation of a complex character (or phonogram, and that of its phonetic radical, while phonological consistency indexes the proportion of orthographic neighbors that share the same pronunciation as the phonogram. In the current investigation, regularity and consistency were contrasted in an event-related potential (ERP study using a lexical decision task and a delayed naming task with native Chinese readers. ERP results showed that effects of regularity occurred early after stimulus onset and were long-lasting. Regular characters elicited larger N170, smaller P200, and larger N400 compared to irregular characters. In contrast, significant effects of consistency were only seen at the P200 and consistent characters showed a greater P200 than inconsistent characters. Thus, both the time course and the direction of the effects indicated that regularity and consistency operated under different mechanisms and were distinct constructs. Additionally, both of these phonological effects were only found in the delayed naming task and absent in lexical decision, suggesting that phonological access was non-obligatory for lexical decision. The study demonstrated cross-language variability in how phonological information was accessed from print and how task demands could influence this process.

  14. Non-Intrusive Load Monitoring of HVAC Components using Signal Unmixing

    Energy Technology Data Exchange (ETDEWEB)

    Rahimpour, Alireza [University of Tennessee, Knoxville (UTK); Qi, Hairong [ORNL; Fugate, David L [ORNL; Kuruganti, Teja [ORNL

    2015-01-01

    Heating, Ventilating and Air Conditioning units (HVAC) are a major electrical energy consumer in buildings. Monitoring of the operation and energy consumption of HVAC would increase the awareness of building owners and maintenance service providers of the condition and quality of performance of these units, enabling conditioned-based maintenance which would help achieving higher energy efficiency. In this paper, a novel non-intrusive load monitoring method based on group constrained non-negative matrix factorization is proposed for monitoring the different components of HVAC unit by only measuring the whole building aggregated power signal. At the first level of this hierarchical approach, power consumption of the building is decomposed to energy consumption of the HVAC unit and all the other electrical devices operating in the building such as lighting and plug loads. Then, the estimated power signal of the HVAC is used for estimating the power consumption profile of the HVAC major electrical loads such as compressors, condenser fans and indoor blower. Experiments conducted on real data collected from a building testbed maintained at the Oak Ridge National Laboratory (ORNL) demonstrate high accuracy on the disaggregation task.

  15. Non-Intrusive Load Monitoring of HVAC Components using Signal Unmixing

    Energy Technology Data Exchange (ETDEWEB)

    Rahimpour, Alireza [University of Tennessee, Knoxville (UTK); Qi, Hairong [ORNL; Fugate, David L [ORNL; Kuruganti, Teja [ORNL

    2015-01-01

    Heating, Ventilating and Air Conditioning units (HVAC) are a major electrical energy consumer in buildings. Monitoring of the operation and energy consumption of HVAC would increase the awareness of building owners and maintenance service providers of the condition and quality of performance of these units, enabling conditioned-based maintenance which would help achieving higher energy efficiency. In this paper, a novel non-intrusive load monitoring method based on group constrained non-negative matrix factorization is proposed for monitoring the different components of HVAC unit by only measuring the whole building aggregated power signal. At the first level of this hierarchical approach, power consumption of the building is decomposed to energy consumption of the HVAC unit and all the other electrical devices operating in the building such as lighting and plug loads. Then, the estimated power signal of the HVAC is used for estimating the power consumption profile of the HVAC major electrical loads such as compressors, condenser fans and indoor blower. Experiments conducted on real data collected from a building testbed maintained at the Oak Ridge National Laboratory (ORNL) demonstrate high accuracy on the disaggregation task.

  16. Solid consistency

    Science.gov (United States)

    Bordin, Lorenzo; Creminelli, Paolo; Mirbabayi, Mehrdad; Noreña, Jorge

    2017-03-01

    We argue that isotropic scalar fluctuations in solid inflation are adiabatic in the super-horizon limit. During the solid phase this adiabatic mode has peculiar features: constant energy-density slices and comoving slices do not coincide, and their curvatures, parameterized respectively by ζ and Script R, both evolve in time. The existence of this adiabatic mode implies that Maldacena's squeezed limit consistency relation holds after angular average over the long mode. The correlation functions of a long-wavelength spherical scalar mode with several short scalar or tensor modes is fixed by the scaling behavior of the correlators of short modes, independently of the solid inflation action or dynamics of reheating.

  17. Exhaustive derivation of static self-consistent multi-soliton solutions in the matrix Bogoliubov-de Gennes systems

    CERN Document Server

    Takahashi, Daisuke A

    2015-01-01

    The matrix-generalized Bogoliubov-de Gennes systems are recently considered by the present author [arXiv:1509.04242], and the time-dependent and self-consistent multi-soliton solutions are constructed based on the ansatz method. In this paper, restricting the problem to the static case, we exhaustively determine the self-consistent solutions using the inverse scattering theory. Solving the gap equation, we rigorously prove that the self-consistent potential must be reflectionless. As a supplementary topic, we elucidate the relation between the stationary self-consistent potentials and the soliton solutions in the matrix nonlinear Schr\\"odinger equation. The asymptotic formulae of multi-soliton solutions for sufficiently isolated solitons are also presented.

  18. 招商银行上海大厦空调系统节能设计%Energy saving design of HVAC system for China Merchants Bank Tower in Shanghai

    Institute of Scientific and Technical Information of China (English)

    滕汜颖; 张伟程

    2014-01-01

    该大楼为超高层办公楼。介绍了空调冷热源和风、水系统中所采用的节能技术和措施,包括冰蓄冷、水蓄热、地源热泵、冷却塔供冷、冷却塔风机可调、大温差供回水、水系统分区、水系统变流量调节、变风量全空气空调、排风热回收、可变新风量。%This building is a super high-rise office building.Presents the adopted energy saving technique and measures including ice storage,water thermal storage,ground-source heat pump,free cooling by cooling tower,adjustable cooling tower fan,large temperature difference of supply and return water,different water system zones,variable flow rate adjustment of water system,variable air volume air conditioning,heat recovery of exhaust air and variable outdoor air.

  19. Airside HVAC BESTEST. Adaptation of ASHRAE RP 865 Airside HVAC Equipment Modeling Test Cases for ASHRAE Standard 140. Volume 1, Cases AE101-AE445

    Energy Technology Data Exchange (ETDEWEB)

    Neymark, J. [J. Neymark & Associates, Golden, CO (United States); Kennedy, M. [Mike D. Kennedy, Inc., Townsend, WA (United States); Judkoff, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gall, J. [AAON, Inc., Tulsa, OK (United States); Knebel, D. [AAON, Inc., Tulsa, OK (United States); Henninger, R. [GARD Analytics, Inc., Arlington Heights, IL (United States); Witte, M. [GARD Analytics, Inc., Arlington Heights, IL (United States); Hong, T. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McDowell, T. [Thermal Energy System Specialists, Madison, WI (United States); Yan, D. [Tsinghua Univ., Beijing (China); Zhou, X. [Tsinghua Univ., Beijing (China)

    2016-03-01

    This report documents a set of diagnostic analytical verification cases for testing the ability of whole building simulation software to model the air distribution side of typical heating, ventilating and air conditioning (HVAC) equipment. These cases complement the unitary equipment cases included in American National Standards Institute (ANSI)/American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 140, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs, which test the ability to model the heat-transfer fluid side of HVAC equipment.

  20. Performance of local orbital basis sets in the self-consistent Sternheimer method for dielectric matrices of extended systems

    OpenAIRE

    2012-01-01

    We present a systematic study of the performance of numerical pseudo-atomic orbital basis sets in the calculation of dielectric matrices of extended systems using the self-consistent Sternheimer approach of [F. Giustino et al., Phys. Rev. B 81 (11), 115105 (2010)]. In order to cover a range of systems, from more insulating to more metallic character, we discuss results for the three semiconductors diamond, silicon, and germanium. Dielectric matrices calculated using our method fall within 1-3...

  1. A sample design for globally consistent biomass estimation using lidar data from the Geoscience Laser Altimeter System (GLAS)

    Science.gov (United States)

    Sean P. Healey; Paul L. Patterson; Sassan S. Saatchi; Michael A. Lefsky; Andrew J. Lister; Elizabeth A. Freeman

    2012-01-01

    Lidar height data collected by the Geosciences Laser Altimeter System (GLAS) from 2002 to 2008 has the potential to form the basis of a globally consistent sample-based inventory of forest biomass. GLAS lidar return data were collected globally in spatially discrete full waveform "shots," which have been shown to be strongly correlated with aboveground forest...

  2. Model-based optimal control of a hybrid power generation system consisting of photovoltaic arrays and fuel cells

    Science.gov (United States)

    Zervas, P. L.; Sarimveis, H.; Palyvos, J. A.; Markatos, N. C. G.

    Hybrid renewable energy systems are expected to become competitive to conventional power generation systems in the near future and, thus, optimization of their operation is of particular interest. In this work, a hybrid power generation system is studied consisting of the following main components: photovoltaic array (PV), electrolyser, metal hydride tanks, and proton exchange membrane fuel cells (PEMFC). The key advantage of the hybrid system compared to stand-alone photovoltaic systems is that it can store efficiently solar energy by transforming it to hydrogen, which is the fuel supplied to the fuel cell. However, decision making regarding the operation of this system is a rather complicated task. A complete framework is proposed for managing such systems that is based on a rolling time horizon philosophy.

  3. Numerical evidence for approximate consistency and Markovianity of some quantum histories in a class of finite closed spin systems.

    Science.gov (United States)

    Schmidtke, Daniel; Gemmer, Jochen

    2016-01-01

    Closed quantum systems obey the Schrödinger equation, whereas nonequilibrium behavior of many systems is routinely described in terms of classical, Markovian stochastic processes. Evidently, there are fundamental differences between those two types of behavior. We discuss the conditions under which the unitary dynamics may be mapped onto pertinent classical stochastic processes. This is first principally addressed based on the notions of "consistency" and "Markovianity." Numerical data are presented that show that the above conditions are to good approximation fulfilled for Heisenberg-type spin models comprising 12-20 spins. The accuracy to which these conditions are met increases with system size.

  4. Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, R.; Agranovski, I.; Pyankov, O. (Griffith Univ., Nathan, Qld (AU)); Grinshpun, S. (Univ. of Cincinnati, Dept. of Environmental Health, Cincinnati, OH (US))

    2008-04-15

    Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approx 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. (au)

  5. Assessing Impact of Large-Scale Distributed Residential HVAC Control Optimization on Electricity Grid Operation and Renewable Energy Integration

    Science.gov (United States)

    Corbin, Charles D.

    Demand management is an important component of the emerging Smart Grid, and a potential solution to the supply-demand imbalance occurring increasingly as intermittent renewable electricity is added to the generation mix. Model predictive control (MPC) has shown great promise for controlling HVAC demand in commercial buildings, making it an ideal solution to this problem. MPC is believed to hold similar promise for residential applications, yet very few examples exist in the literature despite a growing interest in residential demand management. This work explores the potential for residential buildings to shape electric demand at the distribution feeder level in order to reduce peak demand, reduce system ramping, and increase load factor using detailed sub-hourly simulations of thousands of buildings coupled to distribution power flow software. More generally, this work develops a methodology for the directed optimization of residential HVAC operation using a distributed but directed MPC scheme that can be applied to today's programmable thermostat technologies to address the increasing variability in electric supply and demand. Case studies incorporating varying levels of renewable energy generation demonstrate the approach and highlight important considerations for large-scale residential model predictive control.

  6. Effects of Rating Training on Inter-Rater Consistency for Developing a Dental Hygiene Clinical Rater Qualification System

    Directory of Open Access Journals (Sweden)

    Jeong Ran Park

    2007-12-01

    Full Text Available We tried to develop itemized evaluation criteria and a clinical rater qualification system through rating training of inter-rater consistency for experienced clinical dental hygienists and dental hygiene clinical educators. A total of 15 clinical dental hygienists with 1-year careers participated as clinical examination candidates, while 5 dental hygienists with 3-year educations and clinical careers or longer participated as clinical raters. They all took the clinical examination as examinees. The results were compared, and the consistency of competence was measured. The comparison of clinical competence between candidates and clinical raters showed that the candidate group?占퐏 mean clinical competence ranged from 2.96 to 3.55 on a 5-point system in a total of 3 instruments (Probe, Explorer, Curet, while the clinical rater group?占퐏 mean clinical competence ranged from 4.05 to 4.29. There was a higher inter-rater consistency after education of raters in the following 4 items: Probe, Explorer, Curet, and insertion on distal surface. The mean score distribution of clinical raters ranged from 75% to 100%, which was more uniform in the competence to detect an artificial calculus than that of candidates (25% to 100%. According to the above results, there was a necessity in the operating clinical rater qualification system for comprehensive dental hygiene clinicians. Furthermore, in order to execute the clinical rater qualification system, it will be necessary to keep conducting a series of studies on educational content, time, frequency, and educator level.

  7. Demonstration of Standard HVAC Single-Loop Digital Control Systems

    Science.gov (United States)

    1993-01-01

    annubars placed in the ducts. 23 II I __ _j’q_._ II I:I I24 0 (D o 0 0 0 a( ) aU 0- V) C4 CA o V ok 0 C-4 t C-, C-) I.. 25 00 0 Wo- Ln0Q C) 00 00 V) 0...lines were identified and marked, and the wiring schemes were analyzed. Because of budget restrictions, the annubars were not replaced with air flow...retum-fan-inlet-guide vanes to maintain a volumetric air flow that is 1000 cfm less than the supply air flow. The return-air annubar sensor/transmitter

  8. Rightsizing HVAC Systems to Reduce Capital Costs and Save Energy

    Science.gov (United States)

    Sebesta, James

    2010-01-01

    Nearly every institution is faced with the situation of having to reduce the cost of a construction project from time to time through a process generally referred to as "value engineering." Just the mention of those words, however, gives rise to all types of connotations, thoughts, and memories (usually negative) for those in the facilities…

  9. Design And Prototype Testing Of Economizer In HVAC Systems

    OpenAIRE

    Kongara Ajay; Sudhakar, G.

    2014-01-01

    Power, the word itself says to what extent the world is dependent on it. It may be fortunate or unfortunate, we are totally dependent on the power which is making the usage higher and higher which left us with energy crises and increasing costs of the energy usage. It’s time for Energy saving. These days, number of people in favour of the Energy saving has been increasing not to lessen the cost of usage but to let our future generations live with light and luxury. In this p...

  10. Adaptive synchronization of two chaotic systems consisting of modified Van der Pol-Duffing and Chua oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Fotsin, Hilaire [Laboratoire d' electronique, Departement de Physique, Faculte des Sciences, Universite de Dschang, BP 067 Dschang (Cameroon); Laboratoire de Mathematiques Appliquees, Departement de Mathematiques et d' lnformatique, Faculte des sciences, Universite de Douala, BP 24157 Douala (Cameroon); E-mail: hbfotsin@yahoo.fr; Bowong, Samuel [CRAN-INPL-ENSEM-2, Avenue de la Foret de Haye-54516, Vandoeuvre-les-Nancy Cedex (France); E-mail: sbowong@uycdc.uninet.cm; Daafouz, Jamal [Laboratoire de Mathematiques Appliquees, Departement de Mathematiques et d' lnformatique, Faculte des sciences, Universite de Douala, BP 24157 Douala (Cameroon)

    2005-10-01

    In this paper, chaos synchronization between two chaotic systems consisting of modified Van der Pol-Duffing (MVDPD) and Chua oscillators is studied. Such a problem is related to chaos synchronization of different systems. An adaptive feedback synchronization with two controllers is proposed to ensure global chaos synchronization of the modified Van der Pol-Duffing and Chua circuit oscillators. Numerical simulations show the effectiveness of the proposed control method. Moreover, as an application, the proposed scheme is then applied to secure communication whose process consists of a robust filter that recovers the information signal from the scalar transmitted signal. Also, simulation results verify the proposed scheme's success in the communication application.

  11. Lorentz structure vs relativistic consistency of an effective power-law potential model for quark-antiquark systems

    Energy Technology Data Exchange (ETDEWEB)

    Barik, N.; Jena, S.N.

    1982-11-01

    We show here that the relativistic consistency of an effective power-law potential V(r) = Ar/sup ..nu../+V/sub 0/ (with A, ..nu..>0) (used successfully to describe the heavy-meson spectra) in generating Dirac bound states of QQ-bar and Qq-bar systems implies, and also at the same time is implied by, an equally mixed vector-scalar Lorentz structure which was observed phenomenologically in the fine-hyperfine splittings of meson spectra.

  12. Performance of hybrid quad generation system consisting of solid oxide fuel cell system and absorption heat pump

    DEFF Research Database (Denmark)

    Cachorro, Irene Albacete; Daraban, Iulia Maria; Lainé, Guillaume

    2013-01-01

    and absorption heat pump. The model is validated using data available in open literature. Overall this system shows better performance in terms of efficiency and CO2 emissions compared with cogeneration or tri-generation systems. Specifically, it suits better for applications, such food industry, where...

  13. Nonlocal symmetries, consistent Riccati expansion integrability, and their applications of the (2+1)-dimensional Broer-Kaup-Kupershmidt system

    Science.gov (United States)

    Hu, Xiao-Rui; Chen, Yong

    2015-09-01

    For the (2+1)-dimensional Broer-Kaup-Kupershmidt (BKK) system, the nonlocal symmetries related to the Schwarzian variable and the corresponding transformation group are found. Moreover, the integrability of the BKK system in the sense of having a consistent Riccati expansion (CRE) is investigated. The interaction solutions between soliton and cnoidal periodic wave are explicitly studied. Project supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. LQ13A010014) and the National Natural Science Foundation of China (Grant Nos. 11326164, 11401528, 11435005, and 11375090).

  14. Systems biology definition of the core proteome of metabolism and expression is consistent with high-throughput data

    DEFF Research Database (Denmark)

    Yang, Laurence; Tan, Justin; O'Brien, Edward J.

    2015-01-01

    at the systems-level, and provides a basis for computing essential cell functions is lacking. Here, we use a systems biology-based genome-scale model of metabolism and expression to define a functional core proteome consisting of 356 gene products, accounting for 44% of the Escherichia coli proteome by mass...... genitalium). Based on transcriptomics data across environmental and genetic backgrounds, the systems biology core proteome is significantly enriched in nondifferentially expressed genes and depleted in differentially expressed genes. Compared with the noncore, core gene expression levels are also similar...... based on proteomics data. This systems biology core proteome includes 212 genes not found in previous comparative genomics-based core proteome definitions, accounts for 65% of known essential genes in E. coli, and has 78% gene function overlap with minimal genomes (Buchnera aphidicola and Mycoplasma...

  15. Electrostatic MEMS vibration energy harvester for HVAC applications with impact-based frequency up-conversion

    Science.gov (United States)

    Oxaal, J.; Hella, M.; Borca-Tasciuc, D.-A.

    2016-12-01

    This paper reports on electrostatic MEMS vibration energy harvesters with gap-closing interdigitated electrodes, designed for and tested on HVAC air ducts. The harvesters were fabricated on SOI wafers with 200 µm device layer using a custom microfabrication process. Designs with aspects ratio (electrodes’ gap versus depth) of 10 and 20 were implemented, while the overall footprint was approximately 1 cm  ×  1 cm in both cases. In order to enhance the power output, a dual-level physical stopper system was designed to control the minimum gap between the electrodes, which is a key parameter in the conversion process. The dual-level stopper utilizes cantilever beams to absorb a portion of the impact energy as the electrodes approach the impact point, and a film of parylene with nanometer thickness deposited on the electrode sidewalls. The parylene layer defines the absolute minimum gap and provides electrical insulation. The fabricated devices were first tested on a vibration shaker to characterize the resonant behavior. Devices with aspect ratio 10 were found to exhibit frequency up-conversion, which enhances the amount of converted power. Devices with both aspect ratios were found to exhibits spring hardening due to impact with the stoppers and spring softening behavior at increasing voltage bias. The highest power measured on shaker table for sinusoidal vibrations was 3.13 µW (includes enhancement due to frequency up-conversion driven by impact) for aspect ratio 10, and 0.166 µW for aspect ratio 20. The corresponding dimensional figure-of-merit, defined as the power output normalized to vibration acceleration and frequency, squared voltage and device mass, was in the range of 10 · 10-8 m V-2 for both devices, about an order of magnitude higher than state-of-the-art. Testing was carried out on HVAC air duct vibrating with an RMS acceleration of 155 mg RMS, a primary frequency of 60 Hz and a PSD of 7.15 · 10-2 g2 Hz-1. The peak power measured was

  16. Experimental evaluation of a control system for active mass dampers consisting of a position controller and neural oscillator

    Science.gov (United States)

    Sasaki, T.; Iba, D.; Hongu, J.; Nakamura, M.; Moriwaki, I.

    2016-09-01

    This paper shows experimental performance evaluation of a new control system for active mass dampers (AMDs). The proposed control system consists of a position controller and neural oscillator, and is designed for the solution of a stroke limitation problem of an auxiliary mass of the AMDs. The neural oscillator synchronizing with the response of a structure generates a signal, which is utilized for switching of motion direction of the auxiliary mass and for travel distances of the auxiliary mass. According to the generated signal, the position controller drives the auxiliary mass to the target values, and the reaction force resulting from the movement of the auxiliary mass is transmitted to the structure, and reduces the vibration amplitude of the structure. Our previous research results showed that the proposed system could reduce the vibration of the structure while the motion of auxiliary mass was suppressed within the restriction; however the control performance was evaluated numerically. In order to put the proposed system to practical use, the system should be evaluated experimentally. This paper starts by illustrating the relation among subsystems of the proposed system, and then, shows experimental responses of a structure model with the AMD excited by earthquakes on a shaker to confirm the validity of the system.

  17. Performance of local orbital basis sets in the self-consistent Sternheimer method for dielectric matrices of extended systems

    Science.gov (United States)

    Hübener, H.; Pérez-Osorio, M. A.; Ordejón, P.; Giustino, F.

    2012-09-01

    We present a systematic study of the performance of numerical pseudo-atomic orbital basis sets in the calculation of dielectric matrices of extended systems using the self-consistent Sternheimer approach of [F. Giustino et al., Phys. Rev. B 81, 115105 (2010)]. In order to cover a range of systems, from more insulating to more metallic character, we discuss results for the three semiconductors diamond, silicon, and germanium. Dielectric matrices of silicon and diamond calculated using our method fall within 1% of reference planewaves calculations, demonstrating that this method is promising. We find that polarization orbitals are critical for achieving good agreement with planewaves calculations, and that only a few additional ζ's are required for obtaining converged results, provided the split norm is properly optimized. Our present work establishes the validity of local orbital basis sets and the self-consistent Sternheimer approach for the calculation of dielectric matrices in extended systems, and prepares the ground for future studies of electronic excitations using these methods.

  18. Validation of the criteria for initiating the cleaning of heating, ventilation, and air-conditioning (HVAC) ductwork under real conditions.

    Science.gov (United States)

    Lavoie, Jacques; Marchand, Geneviève; Cloutier, Yves; Lavoué, Jérôme

    2011-08-01

    Dust accumulation in the components of heating, ventilation, and air-conditioning (HVAC) systems is a potential source of contaminants. To date, very little information is available on recognized methods for assessing dust buildup in these systems. The few existing methods are either objective in nature, involving numerical values, or subjective in nature, based on experts' judgments. An earlier project aimed at assessing different methods of sampling dust in ducts was carried out in the laboratories of the Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST). This laboratory study showed that all the sampling methods were practicable, provided that a specific surface-dust cleaning initiation criterion was used for each method. However, these conclusions were reached on the basis of ideal conditions in a laboratory using a reference dust. The objective of this present study was to validate these laboratory results in the field. To this end, the laboratory sampling templates were replicated in real ducts and the three sampling methods (the IRSST method, the method of the U.S. organization National Air Duct Cleaner Association [NADCA] and that of the French organization Association pour la Prévention et l'Étude de la Contamination [ASPEC]) were used simultaneously in a statistically representative number of systems. The air return and supply ducts were also compared. Cleaning initiation criteria under real conditions were found to be 6.0 mg/100 cm(2) using the IRSST method, 2.0 mg/100 cm(2) using the NADCA method, and 23 mg/100 cm(2) using the ASPEC method. In the laboratory study, the criteria using the same methods were 6.0 for the IRSST method, 2.0 for the NADCA method, and 3.0 for the ASPEC method. The laboratory criteria for the IRSST and NADCA methods were therefore validated in the field. The ASPEC criterion was the only one to change. The ASPEC method therefore allows for the most accurate evaluation of dust accumulation in HVAC

  19. Field measurements of efficiency and duct retrofit effectiveness in residential forced air distributions systems

    Energy Technology Data Exchange (ETDEWEB)

    Jump, D.A.; Walker, I.S.; Modera, M.P.

    1996-08-01

    Forced air distribution systems can have a significant impact on the energy consumed in residences. It is common practice in U.S. residential buildings to place such duct systems outside the conditioned space. This results in the loss of energy by leakage and conduction to the surroundings. In order to estimate the magnitudes of these losses, 24 houses in the Sacramento, California, area were tested before and after duct retrofitting. The systems in these houses included conventional air conditioning, gas furnaces, electric furnaces and heat pumps. The retrofits consisted of sealing and insulating the duct systems. The field testing consisted of the following measurements: leakage of the house envelopes and their ductwork, flow through individual registers, duct air temperatures, ambient temperatures, surface areas of ducts, and HVAC equipment energy consumption. These data were used to calculate distribution system delivery efficiency as well as the overall efficiency of the distribution system including all interactions with building load and HVAC equipment. Analysis of the test results indicate an average increase in delivery efficiency from 64% to 76% and a corresponding average decrease in HVAC energy use of 18%. This paper summarizes the pre- and post-retrofit efficiency measurements to evaluate the retrofit effectiveness, and includes cost estimates for the duct retrofits. The impacts of leak sealing and insulating will be examined separately. 8 refs., 1 fig., 4 tabs.

  20. State-of-the-art sports facility's HVAC

    Energy Technology Data Exchange (ETDEWEB)

    Horton, M.K. (Gateway Sports Complex, Cleveland, OH (United States))

    1994-08-01

    This article describes the HVAC systems design to keep Cleveland's new Gateway sports and entertainment complex comfortable. This magnificent new facility embraces the 42,000-seat Jacobs Field, with its natural grass playing surface, and the 21,000-seat Arena at Gateway (the official name will be announced at its August 1 opening). The Arena is the new home of the Cleveland Cavaliers NBA basketball team and the Lumberjacks IHL ice hockey team. Other events that will be held here include arena football, circuses, ice shows, and concerts. It is anticipated that the Arena will be in use in excess of 200 days a year for these and other functions. The ballpark and the arena are separated by Gateway Plaza, a large illuminated public space that also will be the site of various entertainment events. An air conditioned pedestrian bridge, approximately 0.7 miles in length, connects the Arena with the Regional Transit Authority's downtown rapid transit station. Other enclosed walkways connect the Arena with two parking garages (3,158 vehicles total) and the larger garage with Jacobs Field.

  1. Performance Charts for a Jet-Propulsion System Consisting of Compressor, a Combustion Chamber, and a Turbine

    Science.gov (United States)

    1946-06-01

    for a Jet-proTulolon system consisting of • conpr«isaor, a ceabustion chanber, and a turbina Rational Advisory Corritte? for Aeronautics, Washington...oc&d air (The effect of change in specific heat of tht* gas during the other processes is Included tn tne principal charts.) A chart is p’.ven...xnand1n,-» the gas from turbine Inlet conditions to the static jr-;i- surt’ at turbine d aehurgo and the klaetic uncrcy oi the gas at the turbine

  2. Luminescence spectroscopy of singlet oxygen enables monitoring of oxygen consumption in biological systems consisting of fatty acids.

    Science.gov (United States)

    Gollmer, Anita; Regensburger, Johannes; Maisch, Tim; Bäumler, Wolfgang

    2013-07-21

    The interaction of singlet oxygen ((1)O2) generated in a photosensitized process with well-known reference photosensitizers Perinaphthenone (PN) and TMPyP is investigated in a model system consisting of fatty acids and the respective exogenous photosensitizer (PS) in solution by direct detection of the luminescence photons of (1)O2 at 1270 nm. Such a model system is a first approach to mimic the complex environment of (1)O2 in a biological cell which consists mainly of water, proteins, sugars and lipids. Firstly, the important issue of oxygen consumption is evaluated which has to be considered during luminescence detection of (1)O2. It is known that the luminescence signal of (1)O2 is dependent on the oxygen concentration of the environment. Cellular components such as lipids represent oxygen consumers due to peroxidation of their unsaturated double bonds. Secondly, the experimental conditions for this model system regarding oxygen consumption are optimized to estimate the rates and rate constants of the coupled system. Thirdly, the triplet decay of the PS can provide more precise information about the actual oxygen concentration close to the PS and can be used, therefore, as a more precise method to determine the oxygen concentration in more complex systems such as a biological cell. The aim is to get a better understanding of photosensitized reactions of (1)O2 with cellular components to further improve methodologies, in particular at a cellular level using luminescence spectroscopy. In conclusion, luminescence detection might be a helpful tool to monitor precisely and promptly changes in oxygen concentration in a complex environment.

  3. Traffic flow characteristics in a mixed traffic system consisting of ACC vehicles and manual vehicles: A hybrid modelling approach

    Science.gov (United States)

    Yuan, Yao-Ming; Jiang, Rui; Hu, Mao-Bin; Wu, Qing-Song; Wang, Ruili

    2009-06-01

    In this paper, we have investigated traffic flow characteristics in a traffic system consisting of a mixture of adaptive cruise control (ACC) vehicles and manual-controlled (manual) vehicles, by using a hybrid modelling approach. In the hybrid approach, (i) the manual vehicles are described by a cellular automaton (CA) model, which can reproduce different traffic states (i.e., free flow, synchronised flow, and jam) as well as probabilistic traffic breakdown phenomena; (ii) the ACC vehicles are simulated by using a car-following model, which removes artificial velocity fluctuations due to intrinsic randomisation in the CA model. We have studied the traffic breakdown probability from free flow to congested flow, the phase transition probability from synchronised flow to jam in the mixed traffic system. The results are compared with that, where both ACC vehicles and manual vehicles are simulated by CA models. The qualitative and quantitative differences are indicated.

  4. Time-dependent restricted-active-space self-consistent-field theory for bosonic many-body systems

    Science.gov (United States)

    Lévêque, Camille; Bojer Madsen, Lars

    2017-04-01

    We develop an ab initio time-dependent wavefunction based theory for the description of a many-body system of cold interacting bosons. Like the multi-configurational time-dependent Hartree method for bosons (MCTDHB), the theory is based on a configurational interaction Ansatz for the many-body wavefunction with time-dependent self-consistent-field orbitals. The theory generalizes the MCTDHB method by incorporating restrictions on the active space of the orbital excitations. The restrictions are specified based on the physical situation at hand. The equations of motion of this time-dependent restricted-active-space self-consistent-field (TD-RASSCF) theory are derived. The similarity between the formal development of the theory for bosons and fermions is discussed. The restrictions on the active space allow the theory to be evaluated under conditions where other wavefunction based methods due to exponential scaling in the numerical effort cannot, and to clearly identify the excitations that are important for an accurate description, significantly beyond the mean-field approach. For ground state calculations we find it to be important to allow a few particles to have the freedom to move in many orbitals, an insight facilitated by the flexibility of the restricted-active-space Ansatz. Moreover, we find that a high accuracy can be obtained by including only even excitations in the many-body self-consistent-field wavefunction. Time-dependent simulations of harmonically trapped bosons subject to a quenching of their noncontact interaction, show failure of the mean-field Gross-Pitaevskii approach within a fraction of a harmonic oscillation period. The TD-RASSCF theory remains accurate at much reduced computational cost compared to the MCTDHB method. Exploring the effect of changes of the restricted-active-space allows us to identify that even self-consistent-field excitations are mainly responsible for the accuracy of the method.

  5. Consistency of the French white certificates evaluation system with the framework proposed for the European energy services

    Energy Technology Data Exchange (ETDEWEB)

    Broc, J.S.; Bourges, B. [GEPEA UMR CNRS, 6144, Ecole des Mines de Nantes, Nantes (France); Osso, D.; Baudry, P. [Electricite de France - R and D, Ecuelles (France); Adnot, J. [Centre for Energy and Processes, Mines ParisTech, Paris (France); Bodineau, L. [Climate Department, ADEME, Angers (France)

    2011-06-15

    According to the directive on energy end-use efficiency and energy services (ESD), the European Member States shall adopt a national indicative energy savings target of 9% (or beyond) in 2016. The issue of the energy savings evaluation is crucial for its implementation. The French White Certificates (FWC) scheme is one of the important measures for France to fulfill its ESD target. However, the accountings of energy savings in the FWC scheme and in the ESD are different. Therefore, an analysis of the consistency of the two systems is needed. A concrete example of actions on residential buildings is used to illustrate the challenges for policy marker and stakeholders to set harmonized evaluation rules. The FWC and ESD calculations appear to be consistent from a physics point of view, as long as calculations are well-documented. But due to differences in the policy objectives, calculation routines may be necessary to convert national energy savings unit (e.g., kWh cumac) into supranational energy savings unit (e.g., ESD kWh). Finally, the work done to establish a transparent evaluation system brings additional benefits (e.g., increased visibility and quality of the actions), which will improve the results of the energy efficiency policies on long term.

  6. Global synchronization in complex networks consisted of systems with the property of x-leading asymptotic stability

    Science.gov (United States)

    Wen, Sun; Chen, Shihua; Wang, Changping

    2008-04-01

    Recently a large set of dynamical systems have been intensively investigated as models of complex networks in which there exist a class of very common systems with the property of x-leading asymptotic stability [R. Zhang, M. Hu, Z. Xu, Phys. Lett. A 368 (2007) 276]. In this Letter, we introduced a new complex network model consisted of this systems, then considered its global synchronization. Based on Lasalle invariance principle, global synchronization criteria is derived. We also do not assume coupling matrix is symmetric and irreducible, so our model is more general than that of [R. Zhang, M. Hu, Z. Xu, Phys. Lett. A 368 (2007) 276]. What is more, our assumption f∈Quad(θ,P,α) is weaker than the assumption f∈Quad(D,P,α) in [W. Lu, T. Chen, Physica D 213 (2006) 214], but it improves synchronization results greatly. Numerical simulations of Lorenz systems as the nodes are given to show the effectiveness of the proposed global asymptotic synchronization criteria.

  7. Global synchronization in complex networks consisted of systems with the property of x{sub k}-leading asymptotic stability

    Energy Technology Data Exchange (ETDEWEB)

    Wen Sun [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China)], E-mail: sunwen_2201@163.com; Chen Shihua [College of Mathematics and Statistics, Wuhan University, Wuhan 430072 (China); Wang Changping [Department of Mathematics and Statistics, Dalhousie University, Halifax NS, B3H 3J5 (Canada)

    2008-04-21

    Recently a large set of dynamical systems have been intensively investigated as models of complex networks in which there exist a class of very common systems with the property of x{sub k}-leading asymptotic stability [R. Zhang, M. Hu, Z. Xu, Phys. Lett. A 368 (2007) 276]. In this Letter, we introduced a new complex network model consisted of this systems, then considered its global synchronization. Based on Lasalle invariance principle, global synchronization criteria is derived. We also do not assume coupling matrix is symmetric and irreducible, so our model is more general than that of [R. Zhang, M. Hu, Z. Xu, Phys. Lett. A 368 (2007) 276]. What is more, our assumption f element of Quad*({theta},P,{alpha}) is weaker than the assumption f element of Quad(D,P,{alpha}) in [W. Lu, T. Chen, Physica D 213 (2006) 214], but it improves synchronization results greatly. Numerical simulations of Lorenz systems as the nodes are given to show the effectiveness of the proposed global asymptotic synchronization criteria.

  8. Comparing administered and market-based water allocation systems through a consistent agent-based modeling framework.

    Science.gov (United States)

    Zhao, Jianshi; Cai, Ximing; Wang, Zhongjing

    2013-07-15

    Water allocation can be undertaken through administered systems (AS), market-based systems (MS), or a combination of the two. The debate on the performance of the two systems has lasted for decades but still calls for attention in both research and practice. This paper compares water users' behavior under AS and MS through a consistent agent-based modeling framework for water allocation analysis that incorporates variables particular to both MS (e.g., water trade and trading prices) and AS (water use violations and penalties/subsidies). Analogous to the economic theory of water markets under MS, the theory of rational violation justifies the exchange of entitled water under AS through the use of cross-subsidies. Under water stress conditions, a unique water allocation equilibrium can be achieved by following a simple bargaining rule that does not depend upon initial market prices under MS, or initial economic incentives under AS. The modeling analysis shows that the behavior of water users (agents) depends on transaction, or administrative, costs, as well as their autonomy. Reducing transaction costs under MS or administrative costs under AS will mitigate the effect that equity constraints (originating with primary water allocation) have on the system's total net economic benefits. Moreover, hydrologic uncertainty is shown to increase market prices under MS and penalties/subsidies under AS and, in most cases, also increases transaction, or administrative, costs.

  9. A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B. C.; Melosh, H. J. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Thebault, P. [LESIA, Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Henning, W. G. [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Gaidos, E. [Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Elkins-Tanton, L. T. [Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States); Bridges, J. C. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Morlok, A., E-mail: johns477@purdue.edu [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2012-12-10

    Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10{sup 19} kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at {approx}6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that {approx}10{sup 47} molecules of SiO vapor are needed to explain an emission feature at {approx}8 {mu}m in the Spitzer IRS spectrum of HD 172555. We find that unless there are {approx}10{sup 48} atoms or 0.05 M{sub Circled-Plus} of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the {approx}8 {mu}m feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

  10. Systems biology definition of the core proteome of metabolism and expression is consistent with high-throughput data.

    Science.gov (United States)

    Yang, Laurence; Tan, Justin; O'Brien, Edward J; Monk, Jonathan M; Kim, Donghyuk; Li, Howard J; Charusanti, Pep; Ebrahim, Ali; Lloyd, Colton J; Yurkovich, James T; Du, Bin; Dräger, Andreas; Thomas, Alex; Sun, Yuekai; Saunders, Michael A; Palsson, Bernhard O

    2015-08-25

    Finding the minimal set of gene functions needed to sustain life is of both fundamental and practical importance. Minimal gene lists have been proposed by using comparative genomics-based core proteome definitions. A definition of a core proteome that is supported by empirical data, is understood at the systems-level, and provides a basis for computing essential cell functions is lacking. Here, we use a systems biology-based genome-scale model of metabolism and expression to define a functional core proteome consisting of 356 gene products, accounting for 44% of the Escherichia coli proteome by mass based on proteomics data. This systems biology core proteome includes 212 genes not found in previous comparative genomics-based core proteome definitions, accounts for 65% of known essential genes in E. coli, and has 78% gene function overlap with minimal genomes (Buchnera aphidicola and Mycoplasma genitalium). Based on transcriptomics data across environmental and genetic backgrounds, the systems biology core proteome is significantly enriched in nondifferentially expressed genes and depleted in differentially expressed genes. Compared with the noncore, core gene expression levels are also similar across genetic backgrounds (two times higher Spearman rank correlation) and exhibit significantly more complex transcriptional and posttranscriptional regulatory features (40% more transcription start sites per gene, 22% longer 5'UTR). Thus, genome-scale systems biology approaches rigorously identify a functional core proteome needed to support growth. This framework, validated by using high-throughput datasets, facilitates a mechanistic understanding of systems-level core proteome function through in silico models; it de facto defines a paleome.

  11. 先进的采暖、通风和空调系统(HVAC)模块技术(Advanced HVAC Module Technology)

    Institute of Scientific and Technical Information of China (English)

    德尔福集团

    2004-01-01

    @@ 采暖、通风和空调系统模块(HVAC)是为了向乘员提供舒适性和安全性所设计的单一模块,可应用于任何车型.先进的HVAC模块拥有全新水准的个性化设定,技术和性能,而且只需很小的装配空间.

  12. Evaluation of the HFACS-ADF safety classification system: inter-coder consensus and intra-coder consistency.

    Science.gov (United States)

    Olsen, Nikki S; Shorrock, Steven T

    2010-03-01

    This article evaluates an adaptation of the human factors analysis and classification system (HFACS) adopted by the Australian Defence Force (ADF) to classify factors that contribute to incidents. Three field studies were undertaken to assess the reliability of HFACS-ADF in the context of a particular ADF air traffic control (ATC) unit. Study one was designed to assess inter-coder consensus between many coders for two incident reports. Study two was designed to assess inter-coder consensus between one participant and the previous original analysts for a large set of incident reports. Study three was designed to test intra-coder consistency for four participants over many months. For all studies, agreement was low at the level of both fine-level HFACS-ADF descriptors and high-level HFACS-type categories. A survey of participants suggested that they were not confident that HFACS-ADF could be used consistently. The three field studies reported suggest that the ADF adaptation of HFACS is unreliable for incident analysis at the ATC unit level, and may therefore be invalid in this context. Several reasons for the results are proposed, associated with the underlying HFACS model and categories, the HFACS-ADF adaptations, the context of use, and the conduct of the studies.

  13. Self-consistent local-density approximation with model Coulomb pair-correlation functions for electronic systems

    Science.gov (United States)

    Gritsenko, O. V.; Rubio, A.; Balbás, L. C.; Alonso, J. A.

    1993-03-01

    The model Coulomb pair-correlation functions proposed several years ago by Gritsenko, Bagaturyants, Kazansky, and Zhidomirov are incorporated into the self-consistent local-density approximation (LDA) scheme for electronic systems. Different correlation functions satisfying well-established local boundary conditions and integral conditions have been tested by performing LDA calculations for closed-shell atoms. Those correlation functions contain a single parameter which can be optimized by fitting the atomic correlation energies to empirical data. In this way, a single (universal) value of the parameter is found to give a very good fit for all the atoms studied. The results provide a substantial improvement of calculated correlation energies as compared to the usual LDA functionals and the scheme should be useful for molecular and cluster calculations.

  14. A self-consistent field study of diblock copolymer/charged particle system morphologies for nanofiltration membranes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo; Ye, Xianggui; Edwards, Brian J., E-mail: bje@utk.edu [Materials Research and Innovation Laboratory (MRAIL), Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2013-12-28

    A combination of self-consistent field theory and density functional theory was used to examine the stable, 3-dimensional equilibrium morphologies formed by diblock copolymers with a tethered nanoparticle attached either between the two blocks or at the end of one of the blocks. Both neutral and interacting particles were examined, with and without favorable/unfavorable energetic potentials between the particles and the block segments. The phase diagrams of the various systems were constructed, allowing the identification of three types of ordered mesophases composed of lamellae, hexagonally packed cylinders, and spheroids. In particular, we examined the conditions under which the mesophases could be generated wherein the tethered particles were primarily located within the interface between the two blocks of the copolymer. Key factors influencing these properties were determined to be the particle position along the diblock chain, the interaction potentials of the blocks and particles, the block copolymer composition, and molecular weight of the copolymer.

  15. An eddy-permitting, dynamically consistent adjoint-based assimilation system for the tropical Pacific: Hindcast experiments in 2000

    KAUST Repository

    Hoteit, Ibrahim

    2010-03-02

    An eddy-permitting adjoint-based assimilation system has been implemented to estimate the state of the tropical Pacific Ocean. The system uses the Massachusetts Institute of Technology\\'s general circulation model and its adjoint. The adjoint method is used to adjust the model to observations by controlling the initial temperature and salinity; temperature, salinity, and horizontal velocities at the open boundaries; and surface fluxes of momentum, heat, and freshwater. The model is constrained with most of the available data sets in the tropical Pacific, including Tropical Atmosphere and Ocean, ARGO, expendable bathythermograph, and satellite SST and sea surface height data, and climatologies. Results of hindcast experiments in 2000 suggest that the iterated adjoint-based descent is able to significantly improve the model consistency with the multivariate data sets, providing a dynamically consistent realization of the tropical Pacific circulation that generally matches the observations to within specified errors. The estimated model state is evaluated both by comparisons with observations and by checking the controls, the momentum balances, and the representation of small-scale features that were not well sampled by the observations used in the assimilation. As part of these checks, the estimated controls are smoothed and applied in independent model runs to check that small changes in the controls do not greatly change the model hindcast. This is a simple ensemble-based uncertainty analysis. In addition, the original and smoothed controls are applied to a version of the model with doubled horizontal resolution resulting in a broadly similar “downscaled” hindcast, showing that the adjustments are not tuned to a single configuration (meaning resolution, topography, and parameter settings). The time-evolving model state and the adjusted controls should be useful for analysis or to supply the forcing, initial, and boundary conditions for runs of other models.

  16. Hydrogen pellet acceleration with a two-stage system consisting of a gas gun and a fuseless electromagnetic railgun

    Energy Technology Data Exchange (ETDEWEB)

    Honig, J.; Kim, K.; Wedge, S.W.

    1986-05-01

    Hydrogen pellets are successfully accelerated for the first time using a two-stage system consisting of a pneumatic gun and an electromagnetic railgun. The pneumatic gun preaccelerator forms cylindrical hydrogen ice pellets (1.6-mm diam x 2.15-mm long) and accelerates them with high-pressure helium gas to velocities in excess of 500 m/s. The booster accelerator, which is a fuseless, circular-bore electromagnetic railgun, derives its propulsive force from a plasma arc armature. The plasma arc armature is formed by electrically breaking down the propellant gas which follows the pellet from the gas gun into the railgun. The diagnostics are for the monitoring of the main capacitor bank and rail currents, for the pellet detection and velocity measurements at the breech and muzzle ends of the railgun, for the recording of the plasma-arc-armature movement inside the railgun bore, and for the photographing of the hydrogen pellet exiting the railgun. Using the system, which is a 60-cm long proof-of-principle machine for refueling magnetic fusion devices, hyrogen pellet velocities exceeding 1 km/s have been achieved for pellets exiting the gas gun at velocities of approx.500 m/s.

  17. Building America Best Practices Series Volume 14 - HVAC. A Guide for Contractors to Share with Homeowners

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gilbride, Theresa L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hefty, Marye G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hand, James R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Love, Pat M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2011-08-01

    This guide, which is part of a series of Best Practices guides produced by DOE’s Building America program, describes ways homeowners can reduce their energy costs and improve the comfort, health, and safety of their homes by upgrading their heating, ventilation, and air conditioning (HVAC) equipment.

  18. Residential and Light Commercial HVAC. Teacher Edition and Student Edition. Second Edition.

    Science.gov (United States)

    Stephenson, David

    This package contains teacher and student editions of a residential and light commercial heating, ventilation, and air conditioning (HVAC) course of study. The teacher edition contains information on the following: using the publication; national competencies; competency profile; related academic and workplace skills list; tools, equipment, and…

  19. Residential and Light Commercial HVAC. Teacher Edition and Student Edition. Second Edition.

    Science.gov (United States)

    Stephenson, David

    This package contains teacher and student editions of a residential and light commercial heating, ventilation, and air conditioning (HVAC) course of study. The teacher edition contains information on the following: using the publication; national competencies; competency profile; related academic and workplace skills list; tools, equipment, and…

  20. Simplified frequency-dependent formulae for series-impedance matrices of single-core HVAC cables

    DEFF Research Database (Denmark)

    Silva, Filipe Miguel Faria da

    2015-01-01

    The installation of HVAC underground cables became more common in recent years, a trend expected to continue in the future. Underground cables are more complex than overhead lines and the calculation of their resistance and reactance can be challenging and time consuming for frequencies that are ...

  1. Influence of Three Dynamic Predictive Clothing Insulation Models on Building Energy Use, HVAC Sizing and Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Kwang Ho Lee

    2014-03-01

    Full Text Available In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the heating season. The assumption is not reflected in practice and thus it may lead to errors. In reality, occupants frequently adjust their clothing depending on the thermal conditions, as opposed to the assumption of constant clothing values above, indicating that the clothing insulation variation should be captured in building simulation software to obtain more reliable and accurate results. In this study, the impact of three newly developed dynamic clothing insulation models on the building simulation is quantitatively assessed using the detailed whole-building energy simulation program, EnergyPlus version 6.0. The results showed that when the heating ventilation and air conditioning system (HVAC is controlled based on indoor temperature the dynamic clothing models do not affect indoor operative temperatures, energy consumption and equipment sizing. When the HVAC is controlled based on the PMV model the use of a fixed clothing insulation during the cooling (0.5 clo and heating (1.0 clo season leads to the incorrect estimation of the indoor operative temperatures, energy consumption and equipment sizing. The dynamic clothing models significantly (p < 0.0001 improve the ability of energy simulation tools to assess thermal comfort. The authors recommend that the dynamic clothing models should be implemented in dynamic building energy simulation software such as EnergyPlus.

  2. An Overview on the Project to Develop Consistent Earth System Data Records for the Global Terrestrial Water Cycle

    Science.gov (United States)

    Sahoo, A. K.; Pan, M.; Gao, H.; Wood, E. F.; Houser, P. R.; Lettenmaier, D. P.; Pinker, R.; Kummerow, C. D.

    2008-12-01

    We aim to develop consistent, long-term Earth System Data Records (ESDRs) for the major components (storages and fluxes) of the terrestrial water cycle at a spatial resolution of 0.5 degrees (latitude-longitude) and for the period 1950 to near-present. The resulting ESDRs are intended to provide a consistent basis for estimating the mean state and variability of the land surface water cycle at the spatial scale of the major global river basins. The ESDRs to produce include a) surface meteorology (precipitation, air temperature, humidity and wind), b) surface downward radiation (solar and longwave) and c) derived and/or assimilated fluxes and storages such as surface soil moisture storage, total basin water storage, snow water equivalent, storage in large lakes, reservoirs, and wetlands, evapotranspiration, and surface runoff. We construct data records for all variables back to 1950, recognizing that the post-satellite data will be of higher quality than pre-satellite (a reasonable compromise given the need for long-term records to define interannual and interdecadal variability of key water cycle variables). A distinguishing feature will be inclusion of two variables that reflect the massive effects of anthropogenic manipulation of the terrestrial water cycle, specifically reservoir storage, and irrigation water use. The overall goal of the project is to develop long term, consistent ESDRs for terrestrial water cycle states and variables by updating and extending previously funded Pathfinder data set activities to the investigators, and by making available the data set to the scientific community and data users via a state-of-the-art internet web-portal. The ESDRs will utilize algorithms and methods that are well documented in the peer reviewed literature. The ESDRs will merge satellite-derived products with predictions of the same variables by LSMs driven by merged satellite and in situ forcing data sets (most notably precipitation), with the constraint that the

  3. Internally consistent thermodynamic data for aqueous species in the system Na-K-Al-Si-O-H-Cl

    Science.gov (United States)

    Miron, George D.; Wagner, Thomas; Kulik, Dmitrii A.; Heinrich, Christoph A.

    2016-08-01

    A large amount of critically evaluated experimental data on mineral solubility, covering the entire Na-K-Al-Si-O-H-Cl system over wide ranges in temperature and pressure, was used to simultaneously refine the standard state Gibbs energies of aqueous ions and complexes in the framework of the revised Helgeson-Kirkham-Flowers equation of state. The thermodynamic properties of the solubility-controlling minerals were adopted from the internally consistent dataset of Holland and Powell (2002; Thermocalc dataset ds55). The global optimization of Gibbs energies of aqueous species, performed with the GEMSFITS code (Miron et al., 2015), was set up in such a way that the association equilibria for ion pairs and complexes, independently derived from conductance and potentiometric data, are always maintained. This was achieved by introducing reaction constraints into the parameter optimization that adjust Gibbs energies of complexes by their respective Gibbs energy effects of reaction, whenever the Gibbs energies of reactant species (ions) are changed. The optimized thermodynamic dataset is reported with confidence intervals for all parameters evaluated by Monte Carlo trial calculations. The new thermodynamic dataset is shown to reproduce all available fluid-mineral phase equilibria and mineral solubility data with good accuracy and precision over wide ranges in temperature (25-800 °C), pressure (1 bar to 5 kbar) and composition (salt concentrations up to 5 molal). The global data optimization process adopted in this study can be readily repeated any time when extensions to new chemical elements and species are needed, when new experimental data become available, or when a different aqueous activity model or equation of state should be used. This work serves as a proof of concept that our optimization strategy is feasible and successful in generating a thermodynamic dataset reproducing all fluid-mineral and aqueous speciation equilibria in the Na-K-Al-Si-O-H-Cl system within

  4. The 55 Cancri Planetary System: Fully Self-Consistent N-body Constraints and a Dynamical Analysis

    CERN Document Server

    Nelson, Benjamin E; Wright, Jason T; Fischer, Debra A; von Braun, Kasper; Howard, Andrew W; Payne, Matthew J; Dindar, Saleh

    2014-01-01

    We present an updated study of the planets known to orbit 55 Cancri A using 1,418 high-precision radial velocity observations from four observatories (Lick, Keck, Hobby-Eberly Telescope, Harlan J. Smith Telescope) and transit time/durations for the inner-most planet, 55 Cancri "e" (Winn et al. 2011). We provide the first posterior sample for the masses and orbital parameters based on self-consistent n-body orbital solutions for the 55 Cancri planets, all of which are dynamically stable (for at least $10^8$ years). We apply a GPU version of Radial velocity Using N-body Differential evolution Markov Chain Monte Carlo (RUN DMC; B. Nelson et al. 2014) to perform a Bayesian analysis of the radial velocity and transit observations. Each of the planets in this remarkable system has unique characteristics. Our investigation of high-cadence radial velocities and priors based on space-based photometry yields an updated mass estimate for planet "e" ($7.99\\pm0.25$ M$_\\oplus$), which affects its density ($5.51\\pm^{1.32}_{...

  5. Consistent model driven architecture

    Science.gov (United States)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  6. 76 FR 37350 - Notice of a Regional Project Waiver of Section 1605 (Buy American) of the American Recovery and...

    Science.gov (United States)

    2011-06-27

    .../air conditioning systems (HVAC Systems) in Columbia, Missouri. This HVAC system consists of three (3... for the HVAC systems, a list of potential manufacturers and project schedule submitted by the City and... HVAC systems available to meet the City's project specifications. The Regional Administrator is...

  7. A sample design for globally consistent biomass estimation using lidar data from the Geoscience Laser Altimeter System (GLAS

    Directory of Open Access Journals (Sweden)

    Healey Sean P

    2012-10-01

    Full Text Available Abstract Background Lidar height data collected by the Geosciences Laser Altimeter System (GLAS from 2002 to 2008 has the potential to form the basis of a globally consistent sample-based inventory of forest biomass. GLAS lidar return data were collected globally in spatially discrete full waveform “shots,” which have been shown to be strongly correlated with aboveground forest biomass. Relationships observed at spatially coincident field plots may be used to model biomass at all GLAS shots, and well-established methods of model-based inference may then be used to estimate biomass and variance for specific spatial domains. However, the spatial pattern of GLAS acquisition is neither random across the surface of the earth nor is it identifiable with any particular systematic design. Undefined sample properties therefore hinder the use of GLAS in global forest sampling. Results We propose a method of identifying a subset of the GLAS data which can justifiably be treated as a simple random sample in model-based biomass estimation. The relatively uniform spatial distribution and locally arbitrary positioning of the resulting sample is similar to the design used by the US national forest inventory (NFI. We demonstrated model-based estimation using a sample of GLAS data in the US state of California, where our estimate of biomass (211 Mg/hectare was within the 1.4% standard error of the design-based estimate supplied by the US NFI. The standard error of the GLAS-based estimate was significantly higher than the NFI estimate, although the cost of the GLAS estimate (excluding costs for the satellite itself was almost nothing, compared to at least US$ 10.5 million for the NFI estimate. Conclusions Global application of model-based estimation using GLAS, while demanding significant consolidation of training data, would improve inter-comparability of international biomass estimates by imposing consistent methods and a globally coherent sample frame. The

  8. 10 CFR 434.403 - Building mechanical systems and equipment.

    Science.gov (United States)

    2010-01-01

    ... both heated and cooled air, duct insulation shall be as required by the most restrictive condition... Insulation. All supply and return air ducts and plenums installed as part of an HVAC air distribution system...-installed plenums, casings, or ductwork furnished as a part of the HVAC equipment tested and rated...

  9. 40 CFR 141.552 - My system consists of “alternative filtration” and is required to conduct a demonstration-what is...

    Science.gov (United States)

    2010-07-01

    ... Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Combined Filter Effluent Requirements § 141.552 My system consists of “alternative filtration” and is required to conduct a demonstration—what... consists of alternative filtration(filtration other than slow sand filtration, diatomaceous...

  10. 松潘某酒店暖通设计%HVAC Design for a Songpan Hotel

    Institute of Scientific and Technical Information of China (English)

    吴毅; 苏华; 汪艳芳

    2013-01-01

    The HVAC systems are designed for a hotel in Songpan, which has a total building area of 7647.1m2, 12 floors and a height of 46.2 m. In this design only consider is heating in winter according to the climatic characteristics. Primary air fan-coil systems are employed in guest room areas (the 4th floor to the 12th floor), with a primary air system for each floor. Ceiling mounted air-handle-units are used in lager spaces such as the gym, KTV (1st-4th floor); in the 1st-4th floor two primary air systems and exhaust ventilation systems are designed respectively. Two vacuum gas/oil boilers are used. A variable-primary-flow two-pipe water system is selected with an expansion tank on the roof. Smoke extraction systems and positive pressure mechanical air supply systems are designed according to national codes.%松潘某酒店建筑总建筑面积7647.1m2,共12层,总建筑高度46.2m。根据气候特点,只考虑冬季供暖,夏季无需空调。4-12层为客房区,采用风机盘管+新风系统,每层设独立新风系统。1-4层健身房、KTV以及后勤用房等采用吊顶空气处理器+新风系统;每层设两个新、排风系统。热源采用两台真空锅炉。空调水系统为一次泵两管制变流量系统,并采用膨胀水箱定压补水。4-12层内走道、健身房和KTV设排烟系统。楼梯间与前室设正压送风系统。

  11. Analysis on Electric Field Around HVAC-HVDC Hybrid Transmission Lines%Analysis on Electric Field Around HVAC-HVDC Hybrid Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    LI Qian; LIU Jun-xiang; LI Hua; LIN Fu-chang

    2011-01-01

    As the transmission line corridors become more and more rare in China, it is now inevitable for people to construct HVAC-HVDC hybrid transmission lines. The research on the electric field around the transmission lines plays an important role in evaluating the electromagnetic environment nearby. However, few existing research now considered the mutual effect of HVAC-HVDC hybrid transmission lines. Thus, this research designed a program based on windows, which calculated the surface voltage gradient on the transmission lines and the electric field at ground level respectively. This research calculated the surface voltage gradient on the transmission lines by applying the improved method of successive images. For the electric field at ground level under AC transmission line, simula- tion charge method is used, while for the electric field at the ground level under DC transmission lines, deutsch as- sumption method is used. Comparing the results generated by the calculation with those in published literature, the program is reliable. Taking 500 kV transmission lines as an example, when considering the mutual effect of the HVAC-HVDC'lines, the amplitude of the surface voltage gradient will increase by about 10% and the amplitude of the electric field at ground level will increase by about 8%, making the mutual effect of the AC and DC lines unneglectable. Larger part of the electric field at ground level under hybrid lines is produced by the DC line. Thus, in order to control the electric field at ground level under hybrid lines, it should pay more attention on that produced by the DC line.

  12. Consistent quantification of climate impacts due to biogenic carbon storage across a range of bio-product systems

    Energy Technology Data Exchange (ETDEWEB)

    Guest, Geoffrey, E-mail: geoffrey.guest@ntnu.no; Bright, Ryan M., E-mail: ryan.m.bright@ntnu.no; Cherubini, Francesco, E-mail: francesco.cherubini@ntnu.no; Strømman, Anders H., E-mail: anders.hammer.stromman@ntnu.no

    2013-11-15

    Temporary and permanent carbon storage from biogenic sources is seen as a way to mitigate climate change. The aim of this work is to illustrate the need to harmonize the quantification of such mitigation across all possible storage pools in the bio- and anthroposphere. We investigate nine alternative storage cases and a wide array of bio-resource pools: from annual crops, short rotation woody crops, medium rotation temperate forests, and long rotation boreal forests. For each feedstock type and biogenic carbon storage pool, we quantify the carbon cycle climate impact due to the skewed time distribution between emission and sequestration fluxes in the bio- and anthroposphere. Additional consideration of the climate impact from albedo changes in forests is also illustrated for the boreal forest case. When characterizing climate impact with global warming potentials (GWP), we find a large variance in results which is attributed to different combinations of biomass storage and feedstock systems. The storage of biogenic carbon in any storage pool does not always confer climate benefits: even when biogenic carbon is stored long-term in durable product pools, the climate outcome may still be undesirable when the carbon is sourced from slow-growing biomass feedstock. For example, when biogenic carbon from Norway Spruce from Norway is stored in furniture with a mean life time of 43 years, a climate change impact of 0.08 kg CO{sub 2}eq per kg CO{sub 2} stored (100 year time horizon (TH)) would result. It was also found that when biogenic carbon is stored in a pool with negligible leakage to the atmosphere, the resulting GWP factor is not necessarily − 1 CO{sub 2}eq per kg CO{sub 2} stored. As an example, when biogenic CO{sub 2} from Norway Spruce biomass is stored in geological reservoirs with no leakage, we estimate a GWP of − 0.56 kg CO{sub 2}eq per kg CO{sub 2} stored (100 year TH) when albedo effects are also included. The large variance in GWPs across the range of

  13. Low Leachable Container System Consisting of a Polymer-Based Syringe with Chlorinated Isoprene Isobutene Rubber Plunger Stopper.

    Science.gov (United States)

    Kiminami, Hideaki; Takeuchi, Katsuyuki; Nakamura, Koji; Abe, Yoshihiko; Lauwers, Philippe; Dierick, William; Yoshino, Keisuke; Suzuki, Shigeru

    2015-01-01

    A 36 month leachable study on water for injection in direct contact within a polymer-based prefillable syringe consisting of a cyclo olefin polymer barrel, a chlorinated isoprene isobutene rubber plunger stopper, a polymer label attached on the barrel, and a secondary packaging was conducted at 25 ± 2 °C and 60 ± 5% relative humidity. Through the various comparison studies, no difference in the leachable amounts was observed between this polymer-based prefilled syringe and a glass bottle as a blank sample reference by 36 months. No influence on the leachables study outcome was noted from the printed label and/or label adhesive or from the secondary packaging. In an additional study, no acrylic acid used as the label adhesive leachable was detected by an extended storage for 45 months at 25 ± 2 °C and 60 ± 5% relative humidity as a worst case. To obtain more details, a comparison extractable study was conducted between a cyclo olefin polymer barrel and a glass barrel. In addition, chlorinated isoprene isobutene rubber and bromo isoprene isobutene rubber were compared. As a result, no remarkable difference was found in the organic extractables for syringe barrels. On the other hand, in the case of element extractable analysis, the values for the cyclo olefin polymer barrel were lower than that for the glass barrel. For the plunger stoppers, the chlorinated isoprene isobutene rubber applied in this study was showing a lower extractable profile as compared to the bromo isoprene isobutene rubber, both for organic and element extractables. In conclusion, the proposed polymer-based prefillable syringe system has great potential and represents a novel alternative that can achieve very low level extractable profiles and can bring additional value to the highly sensitive biotech drug market. A 36 month leachable study on water for injection in direct contact within a cyclo olefin polymer barrel and chlorinated isoprene isobutene rubber plunger stopper that has a

  14. Accelerated fatigue testing of aluminum refrigeration press fittings for HVAC & R applications

    OpenAIRE

    Elbel, Stefan; Duggan, Michael; LaGrotta, Tony; Raj, Sharat; Hrnjak, Pega

    2016-01-01

    Failed brazed joints causing refrigerant leakage is a multi-billion dollar problem for the global HVAC&R industry. Leaks are frequently caused due to mechanical fatigue from extreme pressure cycling, temperature cycling including exposure to freeze/thaw cycles, or vibrational wear induced from rotating electrical machinery. In this study, a new, cost-effective type of press fitting suitable for a wide variety of refrigerants and applications is investigated experimentally. Three tests to acce...

  15. The Rucio Consistency Service

    CERN Document Server

    Serfon, Cedric; The ATLAS collaboration

    2016-01-01

    One of the biggest challenge with Large scale data management system is to ensure the consistency between the global file catalog and what is physically on all storage elements. To tackle this issue, the Rucio software which is used by the ATLAS Distributed Data Management system has been extended to automatically handle lost or unregistered files (aka Dark Data). This system automatically detects these inconsistencies and take actions like recovery or deletion of unneeded files in a central manner. In this talk, we will present this system, explain the internals and give some results.

  16. Estimates of HVAC filtration efficiency for fine and ultrafine particles of outdoor origin

    Science.gov (United States)

    Azimi, Parham; Zhao, Dan; Stephens, Brent

    2014-12-01

    This work uses 194 outdoor particle size distributions (PSDs) from the literature to estimate single-pass heating, ventilating, and air-conditioning (HVAC) filter removal efficiencies for PM2.5 and ultrafine particles (UFPs: Standard 52.2 does not explicitly account for UFP or PM2.5 removal efficiency, estimates of filtration efficiency for both size fractions increased with increasing MERV. Our results also indicate that outdoor PSD characteristics and assumptions for particle density and typical size-resolved infiltration factors (in the absence of HVAC filtration) do not drastically impact estimates of HVAC filter removal efficiencies for PM2.5. The impact of these factors is greater for UFPs; however, they are also somewhat predictable. Despite these findings, our results also suggest that MERV alone cannot always be used to predict UFP or PM2.5 removal efficiency given the various size-resolved removal efficiencies of different makes and models, particularly for MERV 7 and MERV 12 filters. This information improves knowledge of how the MERV designation relates to PM2.5 and UFP removal efficiency for indoor particles of outdoor origin. Results can be used to simplify indoor air quality modeling efforts and inform standards and guidelines.

  17. Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters.

    Science.gov (United States)

    Calfee, M Worth; Rose, Laura J; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

    2014-01-01

    The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p≤0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p>0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident.

  18. Discuss the Technical Difficulties in the Installation of HVAC%刍议暖通空调安装中技术难点

    Institute of Scientific and Technical Information of China (English)

    李金辉

    2014-01-01

    暖通设备安装工程庞大,管道复杂,导致安装时“图纸设计、管线标高与定位交叉安装、水系统水循环、噪音、水凝结、专业配合合理性缺失”等技术难点的产生。本文在论述难点产生的原因同时,给出了相应的处理措施。%The instal ation engineering of HVAC equipment is large with complex pipe, which cause the technical dif iculties of"Drawing design, the cross-instal ation of pipeline elevation and location, pipeline, water condensation and water system, noise, water condensation, and the rationality lack of profes-sional cooperation " when instal the HVAC equipment. This article discusses the causes of the difficulties, and gives the corresponding treatment measures at the same time.

  19. Heat recovery subsystem and overall system integration of fuel cell on-site integrated energy systems

    Science.gov (United States)

    Mougin, L. J.

    1983-01-01

    The best HVAC (heating, ventilating and air conditioning) subsystem to interface with the Engelhard fuel cell system for application in commercial buildings was determined. To accomplish this objective, the effects of several system and site specific parameters on the economic feasibility of fuel cell/HVAC systems were investigated. An energy flow diagram of a fuel cell/HVAC system is shown. The fuel cell system provides electricity for an electric water chiller and for domestic electric needs. Supplemental electricity is purchased from the utility if needed. An excess of electricity generated by the fuel cell system can be sold to the utility. The fuel cell system also provides thermal energy which can be used for absorption cooling, space heating and domestic hot water. Thermal storage can be incorporated into the system. Thermal energy is also provided by an auxiliary boiler if needed to supplement the fuel cell system output. Fuel cell/HVAC systems were analyzed with the TRACE computer program.

  20. $\\sqrt{n}$-consistent parameter estimation for systems of ordinary differential equations: bypassing numerical integration via smoothing

    CERN Document Server

    Gugushvili, Shota

    2010-01-01

    We consider the problem of parameter estimation for a system of ordinary differential equations from noisy observations on a solution of the system. In case the system is nonlinear, as it typically is in practical applications, an analytic solution to it usually does not exist. Consequently, straightforward estimation methods like the ordinary least squares method depend on repetitive use of numerical integration in order to determine the solution of the system for each of the parameter values considered, and to find subsequently the parameter estimate that minimises the objective function. This induces a huge computational load to such estimation methods. We propose an estimator that is defined as a minimiser of an appropriate distance between a nonparametrically estimated derivative of the solution and the right-hand side of the system applied to a nonparametrically estimated solution. Our estimator bypasses numerical integration altogether and reduces the amount of computational time drastically compared t...

  1. Systems and methods for controlling energy use during a demand limiting period

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, Michael J.; Drees, Kirk H.

    2016-04-26

    Systems and methods for limiting power consumption by a heating, ventilation, and air conditioning (HVAC) subsystem of a building are shown and described. A feedback controller is used to generate a manipulated variable based on an energy use setpoint and a measured energy use. The manipulated variable may be used for adjusting the operation of an HVAC device.

  2. The Local Field Factor and Microscopic Cascading: A Self-Consistent Method Applied to Confined Systems of Molecules

    CERN Document Server

    Dawson, Nathan J

    2011-01-01

    We use a simplified self-consistent method to address nonlinear-optical cascading phenomena, which shows added microscopic cascading contributions in high-ordered nonlinear susceptibilities through fifth order. These cascading terms in the microscopic regime encompass all possible scalar cascading configurations. The imposition of geometric constraints further influences the predicted cascading contributions and opens up additional design parameters for nonlinear-optical materials. These results are used in approximating the effective fifth-order susceptibility in thin films of C$_{60}$ monomers of varying thickness and concentration.

  3. Monitoring and control of a hydrogen production and storage system consisting of water electrolysis and metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Herranz, V.; Perez-Page, M. [Departamento de Ingenieria Quimica y Nuclear. Universidad Politecnica de Valencia. Camino de Vera S/N, 46022 Valencia (Spain); Beneito, R. [Area de Energia. Departamento de Gestion e Innovacion. Instituto Tecnologico del Juguete (AIJU). Avda. Industria 23, 03440 Ibi, Alicante (Spain)

    2010-02-15

    Renewable energy sources such as wind turbines and solar photovoltaic are energy sources that cannot generate continuous electric power. The seasonal storage of solar or wind energy in the form of hydrogen can provide the basis for a completely renewable energy system. In this way, water electrolysis is a convenient method for converting electrical energy into a chemical form. The power required for hydrogen generation can be supplied through a photovoltaic array. Hydrogen can be stored as metal hydrides and can be converted back into electricity using a fuel cell. The elements of these systems, i.e. the photovoltaic array, electrolyzer, fuel cell and hydrogen storage system in the form of metal hydrides, need a control and monitoring system for optimal operation. This work has been performed within a Research and Development contract on Hydrogen Production granted by Solar Iniciativas Tecnologicas, S.L. (SITEC), to the Politechnic University of Valencia and to the AIJU, and deals with the development of a system to control and monitor the operation parameters of an electrolyzer and a metal hydride storage system that allow to get a continuous production of hydrogen. (author)

  4. THE POINCARE BIFURCATION OF QUADRATIC SYSTEMS HAVING A REGION CONSISTING OF PERIODIC CYCLES BOUNDED BY A HYPERBOLA AND AN ARC OF EQUATOR

    Institute of Scientific and Technical Information of China (English)

    SongYan

    2005-01-01

    In this paper, we discuss the Poincaré bifurcation for a class of quadratic systems having a region consisting of periodic cycles bounded by a hyperbola and an arc of equator. We prove that the system can at most generate two limit cycles after a small perturbation.

  5. LITERATURE REVIEW: HEAT TRANSFER THROUGH TWO-PHASE INSULATION SYSTEMS CONSISTING OF POWDERS IN A CONTINUOUS GAS PHASE

    Science.gov (United States)

    The report, a review of the literature on heat flow through powders, was motivated by the use of fine powder systems to produce high thermal resistivities (thermal resistance per unit thickness). he term "superinsulations" has been used to describe this type of material, which ha...

  6. An historically consistent and broadly applicable MRV system based on LiDAR sampling and Landsat time-series

    Science.gov (United States)

    W. Cohen; H. Andersen; S. Healey; G. Moisen; T. Schroeder; C. Woodall; G. Domke; Z. Yang; S. Stehman; R. Kennedy; C. Woodcock; Z. Zhu; J. Vogelmann; D. Steinwand; C. Huang

    2014-01-01

    The authors are developing a REDD+ MRV system that tests different biomass estimation frameworks and components. Design-based inference from a costly fi eld plot network was compared to sampling with LiDAR strips and a smaller set of plots in combination with Landsat for disturbance monitoring. Biomass estimation uncertainties associated with these different data sets...

  7. Gel/Space Ratio Evolution in Ternary Composite System Consisting of Portland Cement, Silica Fume, and Fly Ash

    Directory of Open Access Journals (Sweden)

    Mengxue Wu

    2017-01-01

    Full Text Available In cement-based pastes, the relationship between the complex phase assemblage and mechanical properties is usually described by the “gel/space ratio” descriptor. The gel/space ratio is defined as the volume ratio of the gel to the available space in the composite system, and it has been widely studied in the cement unary system. This work determines the gel/space ratio in the cement-silica fume-fly ash ternary system (C-SF-FA system by measuring the reaction degrees of the cement, SF, and FA. The effects that the supplementary cementitious material (SCM replacements exert on the evolution of the gel/space ratio are discussed both theoretically and practically. The relationship between the gel/space ratio and compressive strength is then explored, and the relationship disparities for different mix proportions are analyzed in detail. The results demonstrate that the SCM replacements promote the gel/space ratio evolution only when the SCM reaction degree is higher than a certain value, which is calculated and defined as the critical reaction degree (CRD. The effects of the SCM replacements can be predicted based on the CRD, and the theological predictions agree with the test results quite well. At low gel/space ratios, disparities in the relationship between the gel/space ratio and the compressive strength are caused by porosity, which has also been studied in cement unary systems. The ratio of cement-produced gel to SCM-produced gel ( G C to G S C M ratio is introduced for use in analyzing high gel/space ratios, in which it plays a major role in creating relationship disparities.

  8. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    H. Mirinejad

    2008-01-01

    Full Text Available Problem statement: Heating, Ventilating and Air Conditioning (HVAC systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort field is introduced, followed by a review and comparison of the main existing control techniques used in HVAC systems to date. Results: The present overview shows that intelligent controllers which are based on the human sensation of thermal comfort have a better performance in providing thermal comfort as well as energy saving than the traditional controllers and those based on a model of the HVAC system. Conclusion: Such an overview provides an insight into current control methods in HVAC systems and can help scholars and HVAC learners to have the comprehensive information about a variety of control techniques in the field of HVAC and therefore to better design a proper controller for their work

  9. A Novel Degradation Estimation Method for a Hybrid Energy Storage System Consisting of Battery and Double-Layer Capacitor

    OpenAIRE

    Yuanbin Yu; Dongdong Zhang; Haitao Min; Yi Tang; Tao Zhu(GCAP-CASPER, Physics Department, Baylor University, One Bear Place, # 97316, Waco, TX 76798-7316, U.S.A.)

    2016-01-01

    This paper presents a new method for battery degradation estimation using a power-energy (PE) function in a battery/ultracapacitor hybrid energy storage system (HESS), and the integrated optimization which concerns both parameters matching and control for HESS has been done as well. A semiactive topology of HESS with double-layer capacitor (EDLC) coupled directly with DC-link is adopted for a hybrid electric city bus (HECB). In the purpose of presenting the quantitative relationship between s...

  10. A novel nanomatrix system consisted of colloidal silica and pH-sensitive polymethylacrylate improves the oral bioavailability of fenofibrate.

    Science.gov (United States)

    Jia, Zengrong; Lin, Ping; Xiang, Yu; Wang, Xueqing; Wang, Jiancheng; Zhang, Xuan; Zhang, Qiang

    2011-09-01

    A novel solid particle system with a nanomatrix structure and without surfactant for the oral delivery of insoluble drugs was prepared. This used a combination of pH-sensitive polymethylacrylate and nano-porous silica, in order to improve the drug absorption using only pharmaceutical excipients and a relative simple process. The in vitro drug dissolution and in vivo oral bioavailability of this formulation, using fenofibrate as the model drug, were compared with other reference formulations such as a suspension, micronized formulation or self microemulsion drug delivery system (SMEDDS). The supersaturation stabilizing effect of different polymers was evaluated and the physicochemical characterization of the optimal formulation was conducted by SEM, TEM, surface area analysis, DSC, and XRD. The optimized formulation prepared with polymethylacrylate (Eudragit®L100-55) and silica (Sylysia®350) markedly improved the drug dissolution compared with other reference preparations and displayed a comparative oral bioavailability to the SMEDDS. Fenofibrate existed in a molecular or amorphous state in the nanomatrix, and this state was maintained for up to 1year, without obvious changes in drug release and absorption. In conclusion, the nanomatrix formulation described here is a promising system to enhance the oral bioavailability of water-insoluble drugs. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Adaptive control and synchronization of chaotic systems consisting of Van der Pol oscillators coupled to linear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Fotsin, Hilaire [Laboratoire d' Electronique, Departement de Physique, Faculte des Sciences, Universite de Dschang, B.P. 67 Dschang (Cameroon); INPL-CRAN, UMR CNRS-INPL-UHP 7039 ENSEM-2, Avenue de la Foret de Haye-54516, Vandoeuvre-les-Nancy Cedex (France); E-mail: hbfotsin@yahoo.fr; Bowong, Samuel [Laboratoire de Mathematiques Appliquees, Departement de Mathematiques et Informatique, Faculte des sciences, Universite de Douala, B.P. 24157 Douala (Cameroon)] e-mail: sbowong@uycdc.uninet.cm

    2006-02-01

    This paper deals with the problem of control and synchronization of coupled second-order oscillators showing a chaotic behavior. A classical feedback controller is first used to stabilize the system at its equilibrium. An adaptive observer is then designed to synchronize the states of the master and slave oscillators using a single scalar signal corresponding to an observable state variable of the driving oscillator. An interesting feature of the proposed approach is that it can be used for chaos control as well as synchronization purposes. Numerical simulations results confirming the analytical predictions are shown and pspice simulations are also performed to confirm the efficiency of the proposed control scheme.

  12. A Novel Degradation Estimation Method for a Hybrid Energy Storage System Consisting of Battery and Double-Layer Capacitor

    Directory of Open Access Journals (Sweden)

    Yuanbin Yu

    2016-01-01

    Full Text Available This paper presents a new method for battery degradation estimation using a power-energy (PE function in a battery/ultracapacitor hybrid energy storage system (HESS, and the integrated optimization which concerns both parameters matching and control for HESS has been done as well. A semiactive topology of HESS with double-layer capacitor (EDLC coupled directly with DC-link is adopted for a hybrid electric city bus (HECB. In the purpose of presenting the quantitative relationship between system parameters and battery serving life, the data during a 37-minute driving cycle has been collected and decomposed into discharging/charging fragments firstly, and then the optimal control strategy which is supposed to maximally use the available EDLC energy is presented to decompose the power between battery and EDLC. Furthermore, based on a battery degradation model, the conversion of power demand by PE function and PE matrix is applied to evaluate the relationship between the available energy stored in HESS and the serving life of battery pack. Therefore, according to the approach which could decouple parameters matching and optimal control of the HESS, the process of battery degradation and its serving life estimation for HESS has been summed up.

  13. Tree species composition in areas of Atlantic Forest in southeastern Brazil is consistent with a new system for classifying the vegetation of South America

    Directory of Open Access Journals (Sweden)

    Pedro Vasconcellos Eisenlohr

    2014-06-01

    Full Text Available Rigorous and well-defined criteria for the classification of vegetation constitute a prerequisite for effective biodiversity conservation strategies. In 2009, a new classification system was proposed for vegetation types in extra-Andean tropical and subtropical South America. The new system expanded upon the criteria established in the existing Brazilian Institute of Geography and Statistics classification system. Here, we attempted to determine whether the tree species composition of the formations within the Atlantic Forest Biome of Brazil is consistent with this new classification system. We compiled floristic surveys of 394 sites in southeastern Brazil (between 15º and 25ºS; and between the Atlantic coast and 55ºW. To assess the floristic consistency of the vegetation types, we performed non-metric multidimensional scaling (NMDS ordination analysis, followed by multifactorial ANOVA. The vegetation types, especially in terms of their thermal regimes, elevational belts and top-tier vegetation categories, were consistently discriminated in the first NMDS axis, and all assessed attributes showed at least one significant difference in the second axis. As was expected on the basis of the theoretical background, we found that tree species composition, in the areas of Atlantic Forest studied, was highly consistent with the new system of classification. Our findings not only help solidify the position of this new classification system but also contribute to expanding the knowledge of the patterns and underlying driving forces of the distribution of vegetation in the region.

  14. Testing Postural Stability: Are the Star Excursion Balance Test and Biodex Balance System Limits of Stability Tests Consistent?

    Science.gov (United States)

    Glave, A Page; Didier, Jennifer J; Weatherwax, Jacqueline; Browning, Sarah J; Fiaud, Vanessa

    2016-01-01

    There are a variety of options to test postural stability; however many physical tests lack validity information. Two tests of postural stability - the Star Excursion Balance Test (SEBT) and Biodex Balance System Limits of Stability Test (LOS) - were examined to determine if similar components of balance were measured. Healthy adults (n=31) completed the LOS (levels 6 and 12) and SEBT (both legs). SEBT directions were offset by 180° to approximate LOS direction. Correlations and partial correlations controlling for height were analyzed. Correlations were significant for SEBT 45° and LOS back-left (6: r=-0.41; 12: r=-0.42; pbalance. Research is needed to determine and define what specific components of balance are being assessed. Care must be taken when choosing balance tests to best match the test to the purpose of testing (fall risk, athletic performance, etc.).

  15. Analysis and comparison of NoSQL databases with an introduction to consistent references in big data storage systems

    Science.gov (United States)

    Dziedzic, Adam; Mulawka, Jan

    2014-11-01

    NoSQL is a new approach to data storage and manipulation. The aim of this paper is to gain more insight into NoSQL databases, as we are still in the early stages of understanding when to use them and how to use them in an appropriate way. In this submission descriptions of selected NoSQL databases are presented. Each of the databases is analysed with primary focus on its data model, data access, architecture and practical usage in real applications. Furthemore, the NoSQL databases are compared in fields of data references. The relational databases offer foreign keys, whereas NoSQL databases provide us with limited references. An intermediate model between graph theory and relational algebra which can address the problem should be created. Finally, the proposal of a new approach to the problem of inconsistent references in Big Data storage systems is introduced.

  16. Consistent pattern of local adaptation during an experimental heat wave in a pipefish-trematode host-parasite system.

    Directory of Open Access Journals (Sweden)

    Susanne H Landis

    Full Text Available Extreme climate events such as heat waves are expected to increase in frequency under global change. As one indirect effect, they can alter magnitude and direction of species interactions, for example those between hosts and parasites. We simulated a summer heat wave to investigate how a changing environment affects the interaction between the broad-nosed pipefish (Syngnathus typhle as a host and its digenean trematode parasite (Cryptocotyle lingua. In a fully reciprocal laboratory infection experiment, pipefish from three different coastal locations were exposed to sympatric and allopatric trematode cercariae. In order to examine whether an extreme climatic event disrupts patterns of locally adapted host-parasite combinations we measured the parasite's transmission success as well as the host's adaptive and innate immune defence under control and heat wave conditions. Independent of temperature, sympatric cercariae were always more successful than allopatric ones, indicating that parasites are locally adapted to their hosts. Hosts suffered from heat stress as suggested by fewer cells of the adaptive immune system (lymphocytes compared to the same groups that were kept at 18°C. However, the proportion of the innate immune cells (monocytes was higher in the 18°C water. Contrary to our expectations, no interaction between host immune defence, parasite infectivity and temperature stress were found, nor did the pattern of local adaptation change due to increased water temperature. Thus, in this host-parasite interaction, the sympatric parasite keeps ahead of the coevolutionary dynamics across sites, even under increasing temperatures as expected under marine global warming.

  17. Effectiveness of HVAC duct cleaning procedures in improving indoor air quality.

    Science.gov (United States)

    Ahmad, I; Tansel, B; Mitrani, J D

    2001-12-01

    Indoor air quality has become one of the most serious environmental concerns as an average person spends about 22 hr indoors on a daily basis. The study reported in this article, was conducted to determine the effectiveness of three commercial HVAC (Heating Ventilation Air Conditioning) duct cleaning processes in reducing the level of airborne particulate matter and viable bioaerosols. The three HVAC sanitation processes were: (1) Contact method (use of conventional vacuum cleaning of interior duct surfaces); (2) Air sweep method (use of compressed air to dislodging dirt and debris); (3) Rotary brush method (insertion of a rotary brush into the ductwork to agitate and dislodge the debris). Effectiveness of these sanitation processes was evaluated in terms of airborne particulate and viable bioaerosol concentrations in residential homes. Eight identical homes were selected in the same neighborhood. Two homes were cleaned using each procedure and two were used as controls. It was found that both particle count readings and bioaerosol concentrations were higher when cleaning was being performed than before or after cleaning, which suggests that dirt, debris and other pollutants may become airborne as a result of disturbances caused by the cleaning processes. Particle count readings at 0.3 micron size were found to have increased due to cigarette smoking. Particle counts at 1.0 micron size were reduced due to HVAC duct cleaning. Post-level bioaerosol concentrations, taken two days after cleaning, were found to be lower than the pre-level concentrations suggesting that the cleaning procedures were effective to some extent. Homes cleaned with the Air Sweep procedure showed the highest degree of reduction in bioaerosol concentration among the three procedures investigated.

  18. R and D opportunities for commercial HVAC (heating, air conditioning, and ventilation) equipment

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, S.A.; Zaloudek, F.R.

    1987-03-01

    The overall objective of this project is to identify and characterize generic HVAC equipment research that will provide the best investment opportunities for DOE R and D funds. The prerequisites of a DOE research program include research efforts that are potentially significant in energy conservation impact and that are cost-effective, long-term, and high risk. These prerequisites form the basic guidelines for the R and D opportunities assessed. The assessment excludes the R and D areas that have potential or current private sector sponsors. Finally, R and D areas which are included in DOE programs generally are not addressed.

  19. Improving air handler efficiency in residential HVAC applications

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S.; Mingee, Michael D.; Brenner, Douglas E.

    2003-08-01

    In continuing the development of energy efficiency standards, consideration has turned to air handlers used for heating and air conditioning of consumer residences. These air handlers have typical efficiencies of about 10% to 15% due to poor electric motor performance and aerodynamically poor fans and fan housings. This study was undertaken to examine some of these performance issues, under carefully controlled laboratory conditions, to support potential regulatory changes. In addition, this study examined the performance of a prototype air handler fan assembly that offers the potential for substantial increases in performance. This prototype and a standard production fan were tested in a full-scale duct system and test chamber at LBNL which was specifically designed for testing heating, ventilation, and air conditioning systems. The laboratory tests compared efficiency, total airflow, sensitivity to duct system flow resistance, and the effects of installation in a smaller cabinet. The test results showed that, averaged over a wide range of operating conditions, the prototype air handler had about twice the efficiency of the standard air handler and was less sensitive to duct system flow resistance changes. The performance of both air handlers was significantly reduced by reducing the space between the air handler and the cabinet it was installed in. Therefore any fan rating needs to be performed using the actual cabinet it will be used in.

  20. The relationship between type 2 diabetic patients' early medical care-seeking consistency to the same clinician and health care system and their clinical outcomes.

    Science.gov (United States)

    Liao, Pei-Ju; Lin, Zu-Yu; Huang, Jui-Chu; Hsu, Kuang-Hung

    2015-02-01

    The literature has demonstrated that the continuity of diabetes care can lower medical service utilization and expenses. However, few studies have examined the effects of patients' medical care-seeking behaviors in the early stage after the diagnosis of diabetes on their long-term prognoses. This study aimed to examine the association of medical care-seeking behavior in the first year following diabetes diagnosis on the occurrence of diabetes-related complications among patients in Taiwan. This is a retrospective data collection with follow-up analysis and a nationwide population-based dataset in Taiwan. A total of 89,428 newly diagnosed type 2 diabetes mellitus patients during the period from 2000 to 2006 were followed up until 2010. The patients' medical care-seeking behaviors were classified as follows: high consistency to a physician, high consistency to a medical setting, medium consistency to providers, and low consistency to providers. The occurrence of diabetes-related complications and all-cause mortality were the primary outcomes of this study. Chi-square tests, ANOVAs, and Cox proportional hazard models were applied to examine the relationships between the predictors and medical outcomes. Compared to the patients with high medical care-seeking consistency to a physician, the multivariate-adjusted hazard ratios of diabetes-related complications occurrence among patients in the high consistency to a medical setting, medium consistency, and low consistency categories were 1.112 (95% CI 1.089-1.136, P patient relationship management should be reinforced during the early stage of diabetes care in future medical care systems.

  1. Support Vector Regression and Genetic Algorithm for HVAC Optimal Operation

    Directory of Open Access Journals (Sweden)

    Ching-Wei Chen

    2016-01-01

    Full Text Available This study covers records of various parameters affecting the power consumption of air-conditioning systems. Using the Support Vector Machine (SVM, the chiller power consumption model, secondary chilled water pump power consumption model, air handling unit fan power consumption model, and air handling unit load model were established. In addition, it was found that R2 of the models all reached 0.998, and the training time was far shorter than that of the neural network. Through genetic programming, a combination of operating parameters with the least power consumption of air conditioning operation was searched. Moreover, the air handling unit load in line with the air conditioning cooling load was predicted. The experimental results show that for the combination of operating parameters with the least power consumption in line with the cooling load obtained through genetic algorithm search, the power consumption of the air conditioning systems under said combination of operating parameters was reduced by 22% compared to the fixed operating parameters, thus indicating significant energy efficiency.

  2. Inbreeding avoidance drives consistent variation of fine-scale genetic structure caused by dispersal in the seasonal mating system of Brandt's voles.

    Directory of Open Access Journals (Sweden)

    Xiao Hui Liu

    Full Text Available Inbreeding depression is a major evolutionary and ecological force influencing population dynamics and the evolution of inbreeding-avoidance traits such as mating systems and dispersal. Mating systems and dispersal are fundamental determinants of population genetic structure. Resolving the relationships among genetic structure, seasonal breeding-related mating systems and dispersal will facilitate our understanding of the evolution of inbreeding avoidance. The goals of this study were as follows: (i to determine whether females actively avoided mating with relatives in a group-living rodent species, Brandt's voles (Lasiopodomys brandtii, by combined analysis of their mating system, dispersal and genetic structure; and (ii to analyze the relationships among the variation in fine-genetic structure, inbreeding avoidance, season-dependent mating strategies and individual dispersal. Using both individual- and population-level analyses, we found that the majority of Brandt's vole groups consisted of close relatives. However, both group-specific FISs, an inbreeding coefficient that expresses the expected percentage rate of homozygosity arising from a given breeding system, and relatedness of mates showed no sign of inbreeding. Using group pedigrees and paternity analysis, we show that the mating system of Brandt's voles consists of a type of polygyny for males and extra-group polyandry for females, which may decrease inbreeding by increasing the frequency of mating among distantly-related individuals. The consistent variation in within-group relatedness, among-group relatedness and fine-scale genetic structures was mostly due to dispersal, which primarily occurred during the breeding season. Biologically relevant variation in the fine-scale genetic structure suggests that dispersal during the mating season may be a strategy to avoid inbreeding and drive the polygynous and extra-group polyandrous mating system of this species.

  3. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    OpenAIRE

    H. Mirinejad; Sadati, S.H.; M Ghasemian; H. Torab

    2008-01-01

    Problem statement: Heating, Ventilating and Air Conditioning (HVAC) systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort fiel...

  4. Consistent quantum measurements

    Science.gov (United States)

    Griffiths, Robert B.

    2015-11-01

    In response to recent criticisms by Okon and Sudarsky, various aspects of the consistent histories (CH) resolution of the quantum measurement problem(s) are discussed using a simple Stern-Gerlach device, and compared with the alternative approaches to the measurement problem provided by spontaneous localization (GRW), Bohmian mechanics, many worlds, and standard (textbook) quantum mechanics. Among these CH is unique in solving the second measurement problem: inferring from the measurement outcome a property of the measured system at a time before the measurement took place, as is done routinely by experimental physicists. The main respect in which CH differs from other quantum interpretations is in allowing multiple stochastic descriptions of a given measurement situation, from which one (or more) can be selected on the basis of its utility. This requires abandoning a principle (termed unicity), central to classical physics, that at any instant of time there is only a single correct description of the world.

  5. RPP-PRT-58489, Revision 1, One Systems Consistent Safety Analysis Methodologies Report. 24590-WTP-RPT-MGT-15-014

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Mukesh [URS Professional Solutions LLC, Aiken, SC (United States); Niemi, Belinda [Washington River Protection Solutions, LLC, Richland, WA (United States); Paik, Ingle [Washington River Protection Solutions, LLC, Richland, WA (United States)

    2015-09-02

    In 2012, One System Nuclear Safety performed a comparison of the safety bases for the Tank Farms Operations Contractor (TOC) and Hanford Tank Waste Treatment and Immobilization Plant (WTP) (RPP-RPT-53222 / 24590-WTP-RPT-MGT-12-018, “One System Report of Comparative Evaluation of Safety Bases for Hanford Waste Treatment and Immobilization Plant Project and Tank Operations Contract”), and identified 25 recommendations that required further evaluation for consensus disposition. This report documents ten NSSC approved consistent methodologies and guides and the results of the additional evaluation process using a new set of evaluation criteria developed for the evaluation of the new methodologies.

  6. Long-range Coulomb interactions in surface systems: a first-principles description within self-consistently combined GW and dynamical mean-field theory.

    Science.gov (United States)

    Hansmann, P; Ayral, T; Vaugier, L; Werner, P; Biermann, S

    2013-04-19

    Systems of adatoms on semiconductor surfaces display competing ground states and exotic spectral properties typical of two-dimensional correlated electron materials which are dominated by a complex interplay of spin and charge degrees of freedom. We report a fully ab initio derivation of low-energy Hamiltonians for the adatom systems Si(111):X, with X=Sn, Si, C, Pb, that we solve within self-consistently combined GW and dynamical mean-field theory. Calculated photoemission spectra are in agreement with available experimental data. We rationalize experimentally observed trends from Mott physics toward charge ordering along the series as resulting from substantial long-range interactions.

  7. Chip Multithreaded Consistency Model

    Institute of Scientific and Technical Information of China (English)

    Zu-Song Li; Dan-Dan Huan; Wei-Wu Hu; Zhi-Min Tang

    2008-01-01

    Multithreaded technique is the developing trend of high performance processor. Memory consistency model is essential to the correctness, performance and complexity of multithreaded processor. The chip multithreaded consistency model adapting to multithreaded processor is proposed in this paper. The restriction imposed on memory event ordering by chip multithreaded consistency is presented and formalized. With the idea of critical cycle built by Wei-Wu Hu, we prove that the proposed chip multithreaded consistency model satisfies the criterion of correct execution of sequential consistency model. Chip multithreaded consistency model provides a way of achieving high performance compared with sequential consistency model and ensures the compatibility of software that the execution result in multithreaded processor is the same as the execution result in uniprocessor. The implementation strategy of chip multithreaded consistency model in Godson-2 SMT processor is also proposed. Godson-2 SMT processor supports chip multithreaded consistency model correctly by exception scheme based on the sequential memory access queue of each thread.

  8. Cooling Floor AC Systems

    Science.gov (United States)

    Jun, Lu; Hao, Ding; Hong, Zhang; Ce, Gao Dian

    The present HVAC equipments for the residential buildings in the Hot-summer-and-Cold-winter climate region are still at a high energy consuming level. So that the high efficiency HVAC system is an urgently need for achieving the preset government energy saving goal. With its advantage of highly sanitary, highly comfortable and uniform of temperature field, the hot-water resource floor radiation heating system has been widely accepted. This paper has put forward a new way in air-conditioning, which combines the fresh-air supply unit and such floor radiation system for the dehumidification and cooling in summer or heating in winter. By analyze its advantages and limitations, we found that this so called Cooling/ Heating Floor AC System can improve the IAQ of residential building while keep high efficiency quality. We also recommend a methodology for the HVAC system designing, which will ensure the reduction of energy cost of users.

  9. Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

    Science.gov (United States)

    The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

  10. High-throughput powder diffraction measurement system consisting of multiple MYTHEN detectors at beamline BL02B2 of SPring-8

    Science.gov (United States)

    Kawaguchi, S.; Takemoto, M.; Osaka, K.; Nishibori, E.; Moriyoshi, C.; Kubota, Y.; Kuroiwa, Y.; Sugimoto, K.

    2017-08-01

    In this study, we developed a user-friendly automatic powder diffraction measurement system for Debye-Scherrer geometry using a capillary sample at beamline BL02B2 of SPring-8. The measurement system consists of six one-dimensional solid-state (MYTHEN) detectors, a compact auto-sampler, wide-range temperature control systems, and a gas handling system. This system enables to do the automatic measurement of temperature dependence of the diffraction patterns for multiple samples. We introduced two measurement modes in the MYTHEN system and developed new attachments for the sample environment such as a gas handling system. The measurement modes and the attachments can offer in situ and/or time-resolved measurements in an extended temperature range between 25 K and 1473 K and various gas atmospheres and pressures. The results of the commissioning and performance measurements using reference materials (NIST CeO2 674b and Si 640c), V2O3 and Ti2O3, and a nanoporous coordination polymer are presented.

  11. Self-consistent system of equations for a kinetic description of the low-pressure discharges accounting for the nonlocal and collisionless electron dynamics.

    Science.gov (United States)

    Kaganovich, Igor D; Polomarov, Oleg

    2003-08-01

    In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function (EEDF) deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments made use of simplifying assumptions: a uniform density profile and a Maxwellian EEDF. In the present study, a self-consistent system of equations for the kinetic description of nonlocal, nonuniform, nearly collisionless plasmas of low-pressure discharges is derived. It consists of the nonlocal conductivity operator and the averaged kinetic equation for calculation of the non-Maxwellian EEDF. The importance of accounting for the nonuniform plasma density profile on both the current density profile and the EEDF is demonstrated.

  12. Proposal for a Simple and Efficient Monthly Quality Management Program Assessing the Consistency of Robotic Image-Guided Small Animal Radiation Systems.

    Science.gov (United States)

    Brodin, N Patrik; Guha, Chandan; Tomé, Wolfgang A

    2015-11-01

    Modern pre-clinical radiation therapy (RT) research requires high precision and accurate dosimetry to facilitate the translation of research findings into clinical practice. Several systems are available that provide precise delivery and on-board imaging capabilities, highlighting the need for a quality management program (QMP) to ensure consistent and accurate radiation dose delivery. An ongoing, simple, and efficient QMP for image-guided robotic small animal irradiators used in pre-clinical RT research is described. Protocols were developed and implemented to assess the dose output constancy (based on the AAPM TG-61 protocol), cone-beam computed tomography (CBCT) image quality and object representation accuracy (using a custom-designed imaging phantom), CBCT-guided target localization accuracy and consistency of the CBCT-based dose calculation. To facilitate an efficient read-out and limit the user dependence of the QMP data analysis, a semi-automatic image analysis and data representation program was developed using the technical computing software MATLAB. The results of the first 6-mo experience using the suggested QMP for a Small Animal Radiation Research Platform (SARRP) are presented, with data collected on a bi-monthly basis. The dosimetric output constancy was established to be within ±1 %, the consistency of the image resolution was within ±0.2 mm, the accuracy of CBCT-guided target localization was within ±0.5 mm, and dose calculation consistency was within ±2 s (±3%) per treatment beam. Based on these results, this simple quality assurance program allows for the detection of inconsistencies in dosimetric or imaging parameters that are beyond the acceptable variability for a reliable and accurate pre-clinical RT system, on a monthly or bi-monthly basis.

  13. Reading Development in two Alphabetic Systems Differing in Orthographic Consistency: A longitudinal study of French-speaking children enrolled in a Dutch immersion program

    Directory of Open Access Journals (Sweden)

    Katia Lecocq

    2009-06-01

    Full Text Available Studies examining reading development in bilinguals have led to conflicting conclusions regarding the language in which reading development should take place first. Whereas some studies suggest that reading instruction should take place in the most proficient language first, other studies suggest that reading acquisition should take place in the most consistent orthographic system first. The present study examined two research questions: (1 the relative impact of oral proficiency and orthographic transparency in second-language reading acquisition, and (2 the influence of reading acquisition in one language on the development of reading skills in the other language. To examine these questions, we compared reading development in French-native children attending a Dutch immersion program and learning to read either in Dutch first (most consistent orthography or in French first (least consistent orthography but native language. Following a longitudinal design, the data were gathered over different sessions spanning from Grade 1 to Grade 3. The children in immersion were presented with a series of experimental and standardised tasks examining their levels of oral proficiency as well as their reading abilities in their first and, subsequently in their second, languages of reading instruction. Their performances were compared to the ones of French and Dutch monolinguals. The results showed that by the end of Grade 2, the children instructed to read in Dutch first read in both languages as well as their monolingual peers. In contrast, the children instructed to read in French first lagged behind the other Dutch-speaking groups in Dutch reading tasks. These findings extend the notion that differences across languages in terms of orthographic transparency impact on reading development to the French-Dutch pair, and strongly support the view that there are potentially significant benefits to learn to read in the most consistent orthographic system first

  14. A Dietary Feedback System for the Delivery of Consistent Personalized Dietary Advice in the Web-Based Multicenter Food4Me Study.

    Science.gov (United States)

    Forster, Hannah; Walsh, Marianne C; O'Donovan, Clare B; Woolhead, Clara; McGirr, Caroline; Daly, E J; O'Riordan, Richard; Celis-Morales, Carlos; Fallaize, Rosalind; Macready, Anna L; Marsaux, Cyril F M; Navas-Carretero, Santiago; San-Cristobal, Rodrigo; Kolossa, Silvia; Hartwig, Kai; Mavrogianni, Christina; Tsirigoti, Lydia; Lambrinou, Christina P; Godlewska, Magdalena; Surwiłło, Agnieszka; Gjelstad, Ingrid Merethe Fange; Drevon, Christian A; Manios, Yannis; Traczyk, Iwona; Martinez, J Alfredo; Saris, Wim H M; Daniel, Hannelore; Lovegrove, Julie A; Mathers, John C; Gibney, Michael J; Gibney, Eileen R; Brennan, Lorraine

    2016-06-30

    Despite numerous healthy eating campaigns, the prevalence of diets high in saturated fatty acids, sugar, and salt and low in fiber, fruit, and vegetables remains high. With more people than ever accessing the Internet, Web-based dietary assessment instruments have the potential to promote healthier dietary behaviors via personalized dietary advice. The objectives of this study were to develop a dietary feedback system for the delivery of consistent personalized dietary advice in a multicenter study and to examine the impact of automating the advice system. The development of the dietary feedback system included 4 components: (1) designing a system for categorizing nutritional intakes; (2) creating a method for prioritizing 3 nutrient-related goals for subsequent targeted dietary advice; (3) constructing decision tree algorithms linking data on nutritional intake to feedback messages; and (4) developing personal feedback reports. The system was used manually by researchers to provide personalized nutrition advice based on dietary assessment to 369 participants during the Food4Me randomized controlled trial, with an automated version developed on completion of the study. Saturated fatty acid, salt, and dietary fiber were most frequently selected as nutrient-related goals across the 7 centers. Average agreement between the manual and automated systems, in selecting 3 nutrient-related goals for personalized dietary advice across the centers, was highest for nutrient-related goals 1 and 2 and lower for goal 3, averaging at 92%, 87%, and 63%, respectively. Complete agreement between the 2 systems for feedback advice message selection averaged at 87% across the centers. The dietary feedback system was used to deliver personalized dietary advice within a multi-country study. Overall, there was good agreement between the manual and automated feedback systems, giving promise to the use of automated systems for personalizing dietary advice. Clinicaltrials.gov NCT01530139

  15. 绿色的熊猫兽舍--天津光合谷熊猫兽舍通风空调设计%HVAC of the Green Pander Lair in Tianjin Guanghe Valley

    Institute of Scientific and Technical Information of China (English)

    张骋

    2014-01-01

    熊猫生活在高海拔山区,以其生活环境来分析,其兽舍的通风空调系统的具体要求为:室内无异味、低噪声、低温、潮湿。本工程以“动物福利”为核心,尽量模拟熊猫的生活环境;以绿色建筑为目标,最大限度地实现被动通风,达到较高的室内舒适度;以简单、实用、安全为标准,尽量降低工程造价;力图在使用效果、使用成本、建设成本三者间找到一个平衡点,并使通风空调系统具备多种、灵活的调节手段,使系统达到较高的性价比,从而实现熊猫兽舍通风空调设计的可持续发展。%The giant panda lives high altitude mountain area. Pander lair HVAC requires no smell, no noise, low temperature and humidity by analyzing its survival environment. The lair achieve the target on the passive ventilation as much as possible and indoor comfort level as high as possible, basing‘animal welfare’, simulating real survival environment, aiming to build the green pander lair by taking ordinary, practical and safe HVAC system, and to lower down the cost by building balance among three factors, namely using effect, using cost and building cost. The high cost performance HVAC can be adjusted flexi-bly with diversified methods, in order to achieving the sustainable design of panda lair.

  16. Laboratory measurement of secondary pollutant yields from ozone reaction with HVAC filters.

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Chen, Wenhao; Apte, Michael; Li, Nuan; Spears, Michael; Almosni, J& #233; r& #233; mie; Zhang, Jianshun (Jensen); Fisk, William J.

    2009-09-09

    We used Proton Transfer Reaction - Mass Spectrometry (PTR-MS) and conventional sampling methods to monitor and identify trace level organic pollutants formed in heterogeneous reactions between ozone and HVAC filters in real time. Experiments were carried out using a bench-scale flow tube reactor operating with dry air and humidified air (50% RH), at realistically high ozone concentrations (150 ppbv). We explored different filter media (i.e., fiberglass and cotton/polyester blends) and different particle loadings (i.e., clean filter and filters loaded with particles for 3 months at the Lawrence Berkeley National Laboratory and the Port of Oakland, CA). Detailed emission dynamics of very low levels of certain organic pollutants from filter media upon ozone exposure in the presence of moisture have been obtained and analyzed.

  17. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    Science.gov (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  18. Description of nuclear systems with a self-consistent configuration mixing approach. I: Theory and Algorithm - Application to the $^{12}$C test nucleus

    CERN Document Server

    Robin, C; Arteaga, D Peña; Berger, J -F

    2015-01-01

    Although self-consistent multi-configuration methods have been used for decades to address the description of atomic and molecular many-body systems, only a few trials have been made in the context of nuclear structure. This work aims at the development of such an approach to describe in a unified way various types of correlations in nuclei, in a self-consistent manner where the mean-field is improved as correlations are introduced. The goal is to reconcile the usually set apart Shell-Model and Self-Consistent Mean-Field methods. This approach is referred as "variational multiparticle-multihole configuration mixing method". It is based on a double variational principle which yields a set of two coupled equations that determine at the same time the expansion coefficients of the many-body wave function and the single particle states. The formalism is derived and discussed in a general context, starting from a three-body Hamiltonian. Links to existing many-body techniques such as the formalism of Green's functio...

  19. Market assessment for active solar heating and cooling products. Category B: a survey of decision-makers in the HVAC marketplace. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-09-01

    A comprehensive evaluation of the market for solar heating and cooling products for new and retrofit markets is reported. The emphasis is on the analysis of solar knowledge among HVAC decision makers and a comprehensive evaluation of their solar attitudes and behavior. The data from each of the following sectors are described and analyzed: residential consumers, organizational and manufacturing buildings, HVAC engineers and architects, builders/developers, and commercial/institutional segments. (MHR)

  20. No consistent bimetric gravity?

    CERN Document Server

    Deser, S; Waldron, A

    2013-01-01

    We discuss the prospects for a consistent, nonlinear, partially massless (PM), gauge symmetry of bimetric gravity (BMG). Just as for single metric massive gravity, ultimate consistency of both BMG and the putative PM BMG theory relies crucially on this gauge symmetry. We argue, however, that it does not exist.