Air-cooled chiller screening noise analysis with preliminary building project information

2021 ◽  
Vol 263 (1) ◽  
pp. 5038-5046
Author(s):  
Mark Storm
Keyword(s):  
Noise Analysis ◽  
Cooling Load ◽  
Hvac System ◽  
Noise Emission ◽  
Noise Sources ◽  
Building Projects ◽  
Air Cooled Condensers ◽  
And Function ◽  
Function Information ◽  
Building Project

For Inter-noise 2018, the author submitted a paper proposing techniques to derive reasonable preliminary estimates of building project stationary noise emission levels from sparse but available data that may seem unrelated to noise or vibration such as gross square footage (GSF), expected occupancy, and land use or function. Results from these predictions would be used to support or refine established buffer distances between exposed outdoor heating, ventilating, and air-conditioning (HVAC) system noise sources and nearby noise-sensitive receptors, helping planners tasked with ambitious infill or growth goals better fit building projects into complicated campus development puzzles. This paper provides supplemental guidance by linking the same preliminary building project GSF, occupancy, and function information to estimates of cooling load (expressed as refrigeration tonnage) and thus an additional HVAC consideration not discussed in the author's previous study. When such refrigeration relies upon air-cooled condensers installed outdoors on building rooftops or at grade, substantial noise sources are introduced to the environment. Thus, this new study shares data and methodology to help expand the value and utility of the previous work and potentially provide more comprehensive building HVAC noise estimates for use by building developers and planners.

Microscopy of porous ceramics

1989 ◽  
Vol 47 ◽  
pp. 438-439
Author(s):  
H. M. Kerch ◽  
R. A. Gerhardt
Keyword(s):  
Porous Ceramics ◽  
Specimen Preparation ◽  
High Porosity ◽  
Ion Milling ◽  
Forming Process ◽  
Preparation Methods ◽  
Pore Texture ◽  
Proper Design ◽  
And Function ◽  
Function Information

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.

The role of team leadership in achieving LEED certification in a green building project

2015 ◽  
Vol 5 (2) ◽  
pp. 170-183 ◽  
Author(s):  
Sepani Senaratne ◽  
Prasanna Rajitha Hewamanage
Keyword(s):  
Green Building ◽  
Team Leadership ◽  
Project Team ◽  
Research Approach ◽  
Building Projects ◽  
Content Type ◽  
Leed Certification ◽  
Certification Procedure ◽  
Building Project

Purpose – Leadership of the project team is vital for green building projects in achieving LEED certification. Literature findings confirm the need for managing green building projects differently from ordinary projects. The team leader should be able to work with the project team to manage the general project activities while following the LEED certification procedure to finally achieve LEED certification. The paper aims to discuss these issues. Design/methodology/approach – This paper presents a research project which was aimed to explore the role of team leadership in achieving LEED certification in a green building project through a case study research approach. Findings – The research findings revealed the importance of utilizing the appropriate leadership roles of project team members in addition to the project leader’s role to achieve LEED certification for green building projects successfully. The research proposed four team leadership processes required to meet the LEED challenges; namely, proactive planning and visualization; collective implementation; teamwork for win-win; and, continuous learning and knowledge sharing. Originality/value – Based on these findings, the research suggests a new project team environment enabled by effective team leadership to meet the LEED challenges. It is argued that the team leadership role of every team member is unique and best suited when used synergistically to achieve LEED certification for the project. The research is original in applying team leadership concepts to green building projects in a real-life setting.

scholarly journals Scheduling of building projects taking into account the time buffers determined on the basis of risk analysis

2013 ◽  
Vol 12 (1) ◽  
pp. 047-052
Author(s):  
Mieczysław Połoński
Keyword(s):  
Risk Analysis ◽  
Building Projects ◽  
Time Limits ◽  
Duration Time ◽  
Building Project ◽  
Construction Works ◽  
Reliable Basis

The methodology of development of building project schedules, proposed in the article, is based on an attempt to combine two independent approaches in order to increase the probability of fulfillment of time limits planned in the CPM schedules during the performance of construction works. The analysis of the risk associated with the planned building project will allow for the determination of those tasks which are most threatened by the exceeding of the planned duration time. The application of time buffers, their proper location in the schedule and the determination of their duration, taking into account the expected risk of delays, allow to develop the schedules that contain the appropriate time reserves to compensating for the possible delays. Such a schedule may serve not only as a reliable basis for the determination of the expected deadline for completion of construction works, but also for the management of these works during performance. Selected components of MOCRA and MP-KP methods were proposed in the article.

Experimental Investigation of Noise Sources in a Needle Roller Bearing System

1999 ◽  
Author(s):  
Niccolò Baldanzini ◽  
Federico Beraldo ◽  
Monica Carfagni
Keyword(s):  
Experimental Investigation ◽  
Online Monitoring ◽  
Roller Bearing ◽  
Practical Method ◽  
Sound Power ◽  
Noise Emission ◽  
Noise Sources ◽  
Outer Race ◽  
Bearing System ◽  
Race Analysis

Abstract An experimental investigation was undertaken to determine the causes of noise emission scatter in hosiery machines. Following the experimental measurement of the sound power levels, the hosiery machine’s mechanical system was assembled and tested with components of various sizes. The results indicated that the source of the noise emissions was a bearing’s outer race. Analysis of the outer race’s roundness profile in relation to vibrations provided accurate predictions of machine behavior. On the basis of a correlation between noise and vibrations, a practical method of online monitoring was developed.

Exposure to industrial noise: impacts on cognitive performance

2021 ◽  
Vol 263 (4) ◽  
pp. 2590-2600
Author(s):  
Luiz Henrique Mesa Casa Pereira ◽  
Björn Knöfel ◽  
Jan Troge ◽  
Welf-Guntram Drossel ◽  
Marcel Klein ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Noise Analysis ◽  
Low Frequency ◽  
Cumulative Effect ◽  
Noise Sources ◽  
Industrial Noise ◽  
Sound Levels ◽  
Office Environments ◽  
High Sound ◽  
High Frequency Content

Research on the relation between exposure to noise and cognitive performance inside industrial environments is not as broad as on office environments. For a better understanding of the specific industrial noise problems, participants performed arithmetic tests inside a hemi anechoic room while they were exposed to sounds of five typical industrial noise sources. The subjects also classified how annoying they perceived the noise signals. The effect of noise on the arithmetic test's performance was larger on accuracy than on velocity, which was verified using a Student t-test. Spectral-temporal characteristics - especially high frequency content and strong low frequency modulation - appear to relate better with lower performance on the test than high sound levels. Subjects that evaluated noise as more annoying performed worse in a final arithmetic test (under silence) after being exposed to the noises, indicating a possible cumulative effect of noise on performance. The findings provide a better insight in the cognitive behavior of people who are exposed to industrial noise. Hence, the study will proceed with the specific noise analysis of single industrial workplaces.

scholarly journals A review of causes of variation order in the construction of terrace housing projects in Malaysia

2019 ◽  
Vol 277 ◽  
pp. 03013
Author(s):  
Noraziah Mohammad ◽  
Zabidi Hamzah
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Construction Project ◽  
Extensive Literature ◽  
Time Cost ◽  
Construction Time ◽  
Building Projects ◽  
Housing Projects ◽  
Building Project

Variation order refers to any changes from the scope, plan, specification or contract document in the construction project. This changes of work is a common problem in construction projects in Malaysia. It is inevitable in any construction project and this problem can become more serious when variation order causes work progress to be impaired as a results it increased the construction time and cost that affects the construction industry in Malaysia. This paper critically review the causes of variation order in the construction industry on the double-storey terrace housing project in Malaysia. The discussions began with the construction industry in Malaysia and then related parties involved in the construction industry. The extensive local and abroad literature review on the definitions of variation order and analysis of past studies conducted on variation order and the previous study of the prediction model of variation. The extensive literature on variation order in the construction of building project may help to improve the performance in term of time, cost and quality of the construction of building projects in Malaysia.

Experimental Studies of Excess Noise Sources in Concrete Based Materials as a Limiting Factor for Electromagnetic Emission Measurement

2013 ◽  
Vol 592-593 ◽  
pp. 529-532
Author(s):  
Robert Macků ◽  
Pavel Koktavý ◽  
Tomas Trčka ◽  
Vladimir Holcman
Keyword(s):  
Flicker Noise ◽  
Noise Analysis ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Dielectric Materials ◽  
Excess Noise ◽  
Limiting Factor ◽  
Emission Measurement ◽  
Noise Sources ◽  
Geometrical Properties

This paper deals with excess noise sources in dielectric materials. We focus especially on the concrete samples that are frequently tested to ensure information about the reliability and level of degradation. Nevertheless, the testing methods are limited mainly by the proper contact creation, signal detection and noise defined sensitivity. Our efforts are directed to the noise properties assessment. It turns out that the Johnson-Nyquist noise and the 1/f (flicker) noise are generated in the different regions with the different response to the internal or external electric field. In addition the noise analysis is affected by the internal polarization phenomena and the material residual humidity. This issue in connection with the sample geometrical properties and the dielectric noise measurement methodology take part in this paper.

Synthetic Sound Source Generation for Acoustical Measurements in Turbomachines

2013 ◽  
Author(s):  
Michael Bartelt ◽  
Juan D. Laguna ◽  
Joerg R. Seume
Keyword(s):  
Wind Tunnel ◽  
Sound Source ◽  
Sound Propagation ◽  
Microphone Array ◽  
Sound Field ◽  
Acoustic Mode ◽  
Acoustic Excitation ◽  
Noise Emission ◽  
Noise Sources ◽  
Sound Fields

One of the greatest challenges in modern aircraft propulsion design is the reduction of the engine noise emission in order to develop quieter aircrafts. In the course of a current research project, the sound transport in low pressure turbines is investigated. For the corresponding experimental measurements, a specific acoustic excitation system is developed which can be implemented into the inlet of a turbine test rig and into an aeroacoustic wind tunnel. This allows for an acoustic mode generation and a synthesis of various sound source patterns to simulate typical turbomachinery noise sources such as rotor-stator interaction, etc. The paper presents the acoustical and technical design methodology in detail and addresses the experimental options of the system. Particular attention is paid to the design and the numerical optimization of the acoustic excitation units. To validate the sound generator during operation, measurements are performed in an aeroacoustic wind tunnel. For this purpose, an in-duct microphone array with a specific beamforming algorithm for hard-walled ducts is developed and applied to identify the source locations. The synthetically excited sound fields and the propagating acoustic modes are measured and analyzed by means of modal decomposition techniques. The measurement principles and the results are discussed in detail and it is shown that the intended sound source is produced and the intended sound field is excited. This paper shall contribute to help guide the development of excitation systems for aeroacoustic experiments to better understanding the physics of sound propagation within turbomachines.

Review and Evaluation of Using R-C Thermal Modeling of Cooling Load Prediction for HVAC System Control Purpose

2012 ◽  
Author(s):  
Oluwaseyi T. Ogunsola ◽  
Li Song
Keyword(s):  
Thermal Modeling ◽  
Model Performance ◽  
Hvac Systems ◽  
Measured Data ◽  
System Control ◽  
Cooling Load ◽  
Hvac System ◽  
Monitoring And Control ◽  
Load Prediction ◽  
Total Energy Consumption

Heating and cooling loads which are compensated by heating, ventilation, and air-conditioning (HVAC) systems, are the main reason for energy uses in buildings. Energy utilized by HVAC system accounts for two-thirds of a building’s total energy consumption. Excessive energy is consumed when HVAC systems fail to operate as intended. This is often due to several factors such as inappropriate monitoring and control strategy, lack of understanding of the dynamics of thermal loads, and system complexity. Amidst several models, estimation of cooling load using Resistance Capacitance (RC) models have proved to provide more robust and accurate estimates of the building load based on measured data but the use of this method is not without challenges. This study aims to highlight common challenges associated with implementation of the RC method for thermal modeling of cooling load. Past and current research have handled some of the challenges by introducing simplifying assumptions which if not adequately selected can lead to significant deviation between model performance and measured data. Without proper understanding of the challenges, engineers may not be able to place a high degree of confidence in load calculation methods and the computer implementations that they use.

Sign in / Sign up

Export Citation Format

Share Document