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Chiller plant sizing by cooling load simulation as a means to avoid oversized plant

HKIE Transactions Hong Kong Institution of Engineers 1999年第2期6卷 19-25页

作者： Yik, F.W.H. Lee, W.L. Burnett, J. Jones, P. Department of Building Services Engineering The Hong Kong Polytechnic University Hong Kong Welsh School of Architecture University of Wales United Kingdom

Many buildings in Hong Kong are equipped with oversized chiller plants, which often run at low part-load efficiency. In the paper, the conventional cooling load calculation method for plant sizing and the design criteria used in the calculation are reviewed. Factors that would contribute to overestimation of the required plant capacity are highlighted. With reference to six existing commercial buildings, design peak cooling loads estimated by using the conventional design load calculation method are compared with peak cooling loads predicted by detailed computer simulation, and with the capacities of the existing plants. In addition, the predicted energy use of the chillers based on their installed capacities are compared with the predicted energy use when the capacity of the plants are adjusted to the design cooling load determined using the conventional method, and to the peak load obtained by detailed simulation. It was found that the peak cooling load determined from a detailed simulation on the basis of a typical weather year of Hong Kong forms a good basis for plant sizing. Simulation calculations based on weather conditions for ten consecutive years indicates that a plant sized according to this method is able to meet the building cooling load to a sufficiently high degree of confidence. © 1999 Taylor & Francis Group, LLC.

关键词： Chiller Plant Sizing Design by Simulation Design Load Calculation Energy Efficiency. Building Energy Simulation Oversized Plants

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Determining the causal structure of rework influences in construction

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Construction Management and Economics 1999年第4期17卷 505-517页

作者： Love, P.E.D. Manual, P. Li, H. School of Architecture and Building Deakin University Geelong Vic. 3217 Australia School of Engineering and Technology Deakin University Geelong Vic. 3217 Australia Department of Building and Real Estate Hong Kong Polytechnic University Hong Kong Hong Kong

One of the most perplexing issues facing organizations in the construction industry is their inability to become quality focused. As a result sub-standard products and services often emanate, which inadvertently result in rework. Typically, rework is caused by errors made during the design process. These errors appear downstream in the procurement process and therefore have a negative impact on a project's performance. The lack of attention to quality, especially during the design process, has meant that rework has become an inevitable feature of the procurement process, and the costs have been found to be as high as 12.4% of total project costs. Such costs could be even higher because they do not represent schedule delays, litigation costs and other intangible costs of poor quality. To reduce the cost and effect of rework, an understanding of its causal structure is needed so that effective prevention strategies can be identified and the effects of rework reduced or eliminated. A case study approach based upon deductive and inductive reasoning is used to identify the major factors that influence rework in projects. From the findings and with reference to recent literature, the concept of system dynamics is used to develop a series of influence diagrams, which are then integrated to develop a conceptual causal loop model that is used to determine the overall causal structure of rework. Once an understanding of the causal structure of rework events has been acquired, effective strategies for rework prevention can be designed and implemented in order to improve project performance. This paper contributes to study of quality in construction by capturing the complexity and dynamism of those factors that influence rework and project performance in a holistic manner. © 1999 E&FNSpon.

关键词： Causal loop diagramming Quality management Rework System dynamics

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The Application of Computational Fluid Dynamics to the Prediction of Flow Generated Noise: Part 2: Turbulence-Based Prediction Technique

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Building Acoustics 1998年第3期5卷 201-215页

作者： Mak, C.M. Oldham, D.J. Department of Building Services Engineering Hong Kong Polytechnic University Kowloon Hong Kong Acoustics Research Unit School of Architecture and Building Engineering University of Liverpool LiverpoolL69 3BX United Kingdom

In this paper an engineering approach is followed to investigate the feasibility of developing a method in which information provided by standard CFD turbulence models can be employed as the basis of an airflow noise prediction technique. To this end, experimental results obtained by previous investigators have been processed and compared with CFD predictions. The turbulence-based predictive technique investigated was based on the relationship between the acoustic power radiated due to the interaction of airflow and a spoiler and the turbulent kinetic energy generated in the region of the spoiler. The sound power level of regenerated noise determined experimentally was related to the turbulent kinetic energy in the vicinity of spoiler provided by CFD simulations of the relevant configurations. A collapse of the data from the simulation models was obtained against the experimental data. The data collapse for a particular spoiler was generally excellent for the higher Strouhal numbers but was less good at lower Strouhal numbers where considerable scatter was observed. © 1998, © 1998 Published by Multi-Science Publishing Co. Ltd.

关键词： Computational fluid dynamics

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Arsenal ship program certification plan

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NAVAL ENGINEERS JOURNAL 1998年第1期110卷 249-261页

作者： Arntson, S Lind, W Turner, JJ Blaiklock, WC Tedesco, M Stephen G. Arntson is an independent consultant. A degree Naval Architect he has over 38 years of experience in the design construction and maintenance of surface ships. His experience includes 28 yeus with the Naval Sea Systems Command Naval Ship Engineering Centerl Bureau of Ships specializing in the structural design of Naval surface ships and 7 years with ABS Specializing in the application of commercial ship design practices. Most recently he worked with both NASSCO and ABS MZ the Arsenal Ship Program. Steve was very active with the Ships Structure Committee in developing R&D programs for ship structure and he is a member of the ASNE Journal Committee. Steve received a BS in Mechanical Engineering (Naval Architecture Option) from Virginia Polytechnic Institute in 1964. He is a member of the ASNE TAU BETA PI PI TAU SIGMA and PHI KAPPA PHI. William 1. Lind joined ABS in 1992 after ten years with Sparkman and Stephens Inc. He is currently ABS Amekas Manager of Engineering jm New Orleans and Cleveland. Both ofices conduct plan reviews for militavy commercial and private marine craft fm self-propelled vessels under 300 feet in length and bargus unlimited in length. As Vice-Chaimn ojthe Western Rivers Technical Committee Great Lakes Technical Committee and the Small Vessel Committee Bill participated in the writing of the 1997 ABS Guide for Building and Classing High Speed Craft and the 1997 ABS Rules for Building and Classing Steel Vessels Under 9OM. Bill received an MBA from Florida Atlantic University in 1995 a BS in Mechanical Engineering from New York Institute of Technology in 1986 and a BA in Histoy from Colgate University in 1976. He is Chaimn of SNAME HS-9 Composite Panel Testing & Fire Protection and a member of ASNE. John J. Turner is Senior Vice President of SYNTEK Technologies Inc. in Arlington Virginia. SYNTEK specializes in activities of a highly technical nature supporting both industry and government in domestic and international markets. He is a registered Professional Engineer

The Defense Advanced Research Project Agency (DARPA), in conjunction with the U.S. Navy, initiated a research program for the design and construction of a distinctive warship for the 21st century known as the Arsenal Ship. By using an innovative development and acquisition approach it was hoped to streamline the procurement process and reduce costs. In an environment where budgets are being cut, both industry and Government were challenged to develop, design, and produce the innovative ship and related mission systems to meet specific performance capabilities within strict affordability constraints. A key element of this innovative acquisition approach was a new certification scheme designed to replace the traditional test and evaluation (T&E) and acceptance process. The purpose of this paper is to describe the development of the certification plan during Phase LI of the Arsenal Ship program by the American Bureau of Shipping and the contending Shipyard teams, and to discuss the potential benefits of this alternative certification approach. Although the Arsenal Ship program was canceled late in 1997, insight derived from the exploration of new certification concepts could benefit future design and building programs.

关键词： Warships

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The Prediction of Airflow Generated Noise in Ventilation Systems

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Building Acoustics 1997年第4期4卷 275-294页

作者： Mak, C.M. Waddington, D.C. Oldham, D.J. Department of Building Services Engineering Hong Kong Polytechnic University Kowloon Hong Kong Acoustics Research Unit School of Architecture and Building Engineering University of Liverpool LiverpoolL69 3BX United Kingdom

At long distances from the primary noise source (the fan) of a ventilation system, airflow generated noise from duct fittings can become the major noise problem. There exists only a limited amount of measured data on flow generated noise produced by some in-duct elements such as bends and transition pieces. This lack of data reflects the difficulty in obtaining such information from conventional measurements techniques. As an alternative to large scale data collection, attempts have been made to develop pressure-based techniques for predicting the flow generated noise in a duct. In this paper it is shown that the work of a number of investigators over a long period of time has resulted in the development of techniques for the accurate prediction of flow generated noise due to duct components. © 1997, © 1997 SAGE Publications.

关键词： Ducts

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Trip assignment model for timed-transfer transit systems

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Transportation Research Record 1997年第1571期1571卷 24-30页

作者： Shih, Mao-Chang Mahmassani, Hani S. Baaj, M. Hadi Kaohsiung Polytechnic Institute Civil Engineering Department Kaohsiung County 84008 Taiwan Department of Civil Engineering Uneversity of Texas at Austin Austin TX 78712 United States Dept. of Civ. and Environ. Eng. Fac. of Engineering and Architecture American University of Beirut Beirut Lebanon

A trip assignment model for timed-transfer transit systems is presented. Previously proposed trip assignment models focused on uncoordinated transit systems only. In timed-transfer transit systems, routes arc coordinated and scheduled to arrive at transfer stations within preset time windows. Thus, passenger at coordinated operations terminals may fare a choice among simultaneously departing buses serving alternative routes (unlike the case for uncoordinated operations terminals, where passengers generally board the first vehicle to arrive). A general trip assigment model it proposed that applies different assignment rules for three types of transfer terminals: uncoordinated operations terminals, coordinated operations terminals with a common headway for all routes, and coordinated operations terminals with integer-ratio headways for all routes. In addition, the care of missed connections at transfer termnals (due to vehicle arriving behind schedule) is accounted for. The model has been implemented in the LISP computer language, whose "list" data structure is specially suited to handle path search and enumeration. Results from an application to an example network with defferent combinations of terminal operations and headways indicate the following: (a) demand tends to be assigned to higher-frequqncy paths in the uncordinated transit network: (b) demand is more concentrated, and tends to be assigned to paths with higher frequency and lower travel cost in the cordinated transit network: and (c) missed connections has no significant effects on trip assingment.

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Investigations on delay and CDV in an ATM-based optical access network

Investigations on delay and CDV in an ATM-based optical acce...

引用

IEEE Workshop on ATM

作者： F. Panken J.-M. Barcelo B. Miah S. Winstanley Computing Science Institute University of Nijinegen Toernooiveld Nijmegen Netherlands Computer Architecture Department Polytechnic University of Catalonia Barcelona Spain Department of Electronic Engineering Queen Mary and Westfield College London UK

Modern network technology simplifies considerably the provision of services by providing the user with a unique interface to a single integrated services network which will handle all the user needs. This, however, introduces a very high provision cost and hence cannot be used to connect small and residential users. An access network overcomes this problem, allowing a relative large number of small scale users to share resources such that traffic is concentrated and a single point of entry to the high speed network can be used in a more economical manner. This paper presents the result of an investigation carried out to explore some of the issues concerning a real optical access network which supports ATM and assumes a passive optical network with a tree topology as its distribution network. The paper describes all the important features of the network and reveals the results of the experiments that were carried out on a demonstrator. These experiments were performed using a traffic generator to multiplex heterogeneous mixes of traffic and study the performance of the access network under different load conditions. This study is compared with simulation results and reveal that the implemented access network operates as it was designed to do. Furthermore, the slot format used, which assumes only a small overhead, is seen to be sufficient for APON technology. Finally, the results show that the medium access control protocol, which was specially designed for the demonstrator, distributes the available data rate over all the termination points in a flexible, efficient and robust way.

关键词： Delay Passive optical networks Telecommunication traffic High speed optical techniques Traffic control Intserv networks Costs High-speed networks Optical fiber networks Asynchronous transfer mode

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Advanced double hull structural design technology

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 117-127页

作者： Sikora, J Grassman, JM Sensharma, P Watts, J Jerry Sikora:has been with the Naval Surface Warfare Center Carderock Division (NSWCCD) since he received his B.S. degree in physics f r m the University of Detroit in 1969. He is the head of the Design Applications Branch of the Structures and Cmposites Department. Mx Sikora began his career in the field of holographic and other optical measurements of structural parameters. Over the past decade and a half he has developed probability based loads criteria for conventional and SWATH ships. Recently he has been involved in developing structural design criteria and design methods for the cellular structure of advanced double hull ships. Jon M. Grassman:received his B.S. degree in ocean engi-neering from Texas A & M University in 1987. Following graduation he joined the Design Applications Branch at NSWCCD. He has been primarily involved in the application of finite element methods for the design and analysis of naval ships SWATHS and advanced double hull combatant and commercial ships. Pradeep Sensharma:received his B.S. degree in naval architecture from the Indian Institute of Technology Kharagpul: India in 1981. Following that he worked in the Design and Development Section of Mazagon Dock Ltd. Bombay India for five years. He received his M.S. degree in 1988 and his doctoral degree in 1993 from Virginia Polytechnic Institute and State University. Dr. Sensharma specializes in finite element analysis and optimization. He joined Designers & Planners Inc. In 1995. Recently he has been involved In the design and analysis of advanced double hull ships. Joan Watts:is currently the director of naval architecture for Designers & Planners Inc. Arlington Virginia. She graduated from the University of Michigan with a B.S.E. in naval architecture and marine engineering in 1979. Since graduation she has been employed as a naval architect with various consulting firms mainly in the Washington D. C. area.

The Mid-Term Sealift Ship Technology Development Program is a multiyear research and development effort to examine promising technologies for application to construction of sealift ships. One of the goals of this program is to enhance the competitiveness of U.S. shipbuilders by investigating a new method of hull construction that would be easier and cheaper to build and preoutfit. The concept consists of a long-spanned, unidirectionally-stiffened structural system where the main structural elements are arranged longitudinally This technology is referred to as advanced double hull (ADH). This paper describes the second year of study in which a new design criterion was applied. This criterion was based upon the results of structural testing and analysis conducted by the Naval Surface Warfare Center Carderock Division (NSWCCD) to determine the ultimate strength of cellular structure. A full ship finite element model was developed to help validate the structural criteria.

关键词： Hulls (ship)

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A bilateral negotiation model of technology pricing

A bilateral negotiation model of technology pricing

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IEEE International Conference on Systems, Man and Cybernetics

作者： Liping Fang Yuanfang Song Yingluo Wang Department of Mechanical Engineering Ryerson Polytechnic University Toronto ONT Canada Department of Mechanical Engineering Ryerson Polytechnic University Canada Department of Management Qingdao Institute of Architecture and Engineering Qingdao Shandong China School of Management Xi'an Jiaotong University Xi'an Shanxi China

ISBN: (纸本)0780332806

A bilateral negotiation model is presented to study the negotiation process involved in arriving at a price in a technology transfer transaction. It is assumed that each side in the negotiation knows his/her own reservation price and has an estimate of the other side's reservation price. An estimate for the other side's desired price at each round of the negotiation is developed and a rule is established for accepting the next offer/counteroffer made by the other side. A numerical example is used to illustrate the application of the negotiation model.

关键词： Pricing Technology transfer Manufacturing Technology management engineering management Helium

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A light duty universal direct sunlight heliodon

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Architectural Science Review 1996年第4期39卷 187-191页

作者： Lo, L.M. Sin, S.K. Cheung, K.P. Chu, C.Y. Siu, C. Department of Architecture The University of Hong Kong Pokfulam Road Hong Kong Dept. Of Mechnical and Marine Engineering Hong Kong Polytechnic University Kowloon Hung Horn Hong Kong

Direct sunlight testing of building models are currently operated with sundials and tripods (Robbins 1986a) such that the model is adjusted together with the sundial as one integral piece for choosing the time and the day for which the model is to be tested. When the sun has moved appreciably, adjustment of the set up has to be made correspondingly. Furthermore this method does not offer the convenience for testing the model quickly over a wide range of time of the same day, nor would it do so for different days of the year when a certain time (apparent solar time) is selected. This paper reports on a new universal direct sunlight heliodon that can overcome this inconvenience. © 1996 Taylor & Francis Group, LLC.

关键词： Heliodon Solarscope Sun machine

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