DOCSLIB.ORG

1 Assessment and Improvement of the 2019 ASHRAE Handbook Model for Exhaust-To- Intake Dilution Calculations for Rooftop Exhaust

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
1 Assessment and Improvement of the 2019 ASHRAE Handbook Model for Exhaust-To- Intake Dilution Calculations for Rooftop Exhaust Assessment and improvement of the 2019 ASHRAE Handbook model for exhaust-to- intake dilution calculations for rooftop exhaust systems (ASHRAE 1823-RP) Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Saba Zakeri Shahvari Graduate Program in Mechanical Engineering The Ohio State University 2020 Thesis Committee Jordan Clark, Advisor Andy May 1 Copyrighted by Saba Zakeri Shahvari 2020 2 Abstract The HVAC Applications volume of the 2019 ASHRAE Handbook: Chapter 46 gives multiple procedures for sizing building exhaust stacks and fans. The most complex of these procedures directly calculates dilution at a receptor of interest using plume theory and several empirical constants. There is suggestion in the literature that this model leads to overly conservative dilution predictions in some cases. The purpose of this work is to determine whether the ASHRAE model can be improved to give more accurate dilution predictions. First, the predictions of the existing equation are evaluated against several existing wind tunnel and full-scale studies and their shortcomings noted. The results show that the 2019 model under-predicts observed dilution mainly in two cases: near the stack and when the plume was within the assumed recirculation region. The assumptions for initial plume spread, height of recirculation zone region, plume spread and plume trajectory were varied parametrically to identify a better model. This optimized model can increase dilution predictions by factors between 2 and 500, while bounding measured data in all cases analyzed. This can reduce the required momentum ratio by 20-70%, leading to much more efficient fan sizing and operation. Keywords: dispersion modeling, exhaust stacks, building air intakes, plume modeling, laboratory ventilation, hospital ventilation, vivariums iii Dedication Dedicated to my supervisor Dr. Jordan Clark for his help and guidance, and my family and friends for their support and encouragement from thousands of miles away. iv Acknowledgments I wish to express my sincere gratitude to my supervisor Dr. Jordan Clark for his advice and guidance through this research project. v Vita Saba Zakeri Shahvari Education BSc. in Mechanical Engineering at Amirkabir University of Technology, Tehran, Iran, May 2018 Highschool Diploma, Farzanegan High School, Bandarabbas, Iran, June 2013 Work Teaching associate at Amirkabir University of Technology, Tehran, Iran, Winter 2018 Fields of Study Major Field: Mechanical Engineering vi Table of Contents Abstract .............................................................................................................................. iii Dedication .......................................................................................................................... iv Acknowledgments............................................................................................................... v Vita ..................................................................................................................................... vi List of Tables ..................................................................................................................... ix List of Figures ..................................................................................................................... x Chapter 1. Introduction ....................................................................................................... 1 1.1 Height of recirculation zone or tallest active obstacle, htop ....................................... 3 1.2 Initial source size, σo ................................................................................................. 5 1.3 Lateral and vertical plume spread, y and z ............................................................ 6 1.4 Surrounding terrain surface roughness, z0 ................................................................ 6 Chapter 2. Methodology ..................................................................................................... 8 2.1 Hajra and Stathopoulos, 2012 ................................................................................... 8 2.2 Gupta et al., 2012 ...................................................................................................... 8 2.3 ASHRAE Research Project 805: Petersen, et.al, 1997 ........................................... 10 2.4 Schulman & Scire, 1991 ......................................................................................... 10 2.5 Wilson & Chui, 1994 .............................................................................................. 10 2.6 Wilson & Lamb, 1994............................................................................................. 11 Chapter 3. Results ............................................................................................................. 17 3.1 Existing equation evaluation ................................................................................... 17 3.1.1 Hajra and Stathopoulos, 2012 .......................................................................... 17 3.1.2 Gupta et al., 2012 ............................................................................................. 18 3.1.3 ASHRAE Research Project 805, Petersen, et.al, 1997 .................................... 20 3.1.4 Schulman & Scire, 1991 .................................................................................. 22 3.1.5 Wilson & Chui, 1994 ....................................................................................... 24 vii 3.1.6 Wilson & Lamb, 1994...................................................................................... 24 3.2 Optimization ........................................................................................................... 26 3.3 Evaluation of the recommended procedure to choose the surface roughness ........ 31 4 Conclusions and Recommendations .............................................................................. 33 Bibliography ..................................................................................................................... 35 Appendix A. ASHRAE Minimum Dilution Model ......................................................... 36 Appendix B. Optimization Results for All Data Bases..................................................... 40 viii List of Tables Table 1 Characteristic parameters of each test from Wilson and Chui, 1994 ................... 11 Table 2 Characteristic parameters of each test from Wilson and Lamb, 1994 ................. 12 Table 3 Progressive improvement of model through addition of variables and effect on objective function.............................................................................................................. 27 Table 4 Optimized values checked on other data sets results ........................................... 30 ix List of Figures Figure 1 Relationship between htop and hplume for three different scenarios........................ 4 Figure 2 Observed and predicted dilutions for Hajra & Stathopolous (2012) .................. 17 Figure 3 Observed and predicted dilutions from Gupta et al. (2012) ............................... 18 Figure 4 Observed and predicted dilutions from ASHRAE RP 805 (1997) ..................... 20 Figure 5 Observed and predicted dilutions from Schulman & Scire (1991) .................... 22 Figure 6 Observed and predicted dilutions from Wilson & Chui (1994) ......................... 24 Figure 7 Observed and predicted dilutions from Wilson & Chui (1994) ......................... 25 Figure 8 Effect of surface roughness on predicted dilution (1) ........................................ 31 Figure 9 Effect of surface roughness on predicted dilution (2) ........................................ 32 Figure 10 Original and optimized dilution predictions for Hajra & Stathepolus (2012) .. 40 Figure 11 Original and optimized dilution predictions for Gupta et al. (2012) ................ 41 Figure 12 Original and optimized dilution predictions for ASHRAE RP 805 (0 Degree) 42 Figure 13 Original and optimized dilution predictions for ASHRAE RP 805 (45 Degree) ........................................................................................................................................... 43 Figure 14 Original and optimized dilution predictions for Schulman & Scire, 1991 (0 Degree) .............................................................................................................................. 44 Figure 15 Original and optimized dilution predictions for Schulman & Scire, 1991 (45 Degree) .............................................................................................................................. 45 Figure 16 Log of dilution ratio versus distance from the stack (Original) ....................... 46 Figure 17 Log of dilution ratio versus distance from the stack (With cut-off) ................. 46 Figure 18 Log of dilution ratio versus distance from the stack (Optimized with the variable ) .......................................................................................................................... 47 Figure 19 Log of dilution ratio versus distance from the stack (Optimized with the variables and ) .............................................................................................................. 47 Figure 20 Log of dilution ratio versus distance from the stack (Optimized with the variables ay, az, and ) ...................................................................................................
Load more

Recommended publications
  • ASHRAE Position Document on Filtration and Air Cleaning
    ASHRAE Position Document on Filtration and Air Cleaning Approved by ASHRAE Board of Directors January 29, 2015 Reaffirmed by Technology Council January 13, 2018 Expires January 23, 2021 ASHRAE 1791 Tullie Circle, NE • Atlanta, Georgia 30329-2305 404-636-8400 • fax: 404-321-5478 • www.ashrae.org © 2015 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission. COMMITTEE ROSTER The ASHRAE Position Document on Filtration and Air Cleaning was developed by the Society's Filtration and Air Cleaning Position Document Committee formed on January 6, 2012, with Pawel Wargocki as its chair. Pawel Wargocki, Chair Dean A. Saputa Technical University of Denmark UV Resources Kongens Lyngby, Denmark Santa Clarita, CA Thomas H. Kuehn William J. Fisk University of Minnesota Lawrence Berkeley National Laboratory Minneapolis, MN Berkeley, CA H.E. Barney Burroughs Jeffrey A. Siegel Building Wellness Consultancy, Inc. The University of Toronto Johns Creek, GA Toronto, ON, Canada Christopher O. Muller Mark C. Jackson Purafil Inc. The University of Texas at Austin Doraville, GA Austin, TX Ernest A. Conrad Alan Veeck BOMA International National Air Filtration Association Washington DC Virginia Beach, VA Other contributors: Dean Tompkins Madison, WI for his contribution on photocatalytic oxidizers Paul Francisco, Ex-Officio Cognizant Committee Chair Environmental Health Committee University of Illinois Champaign, IL ASHRAE is a registered trademark in the U.S. Patent and Trademark Office, owned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. © 2015 ASHRAE (www.ashrae.org). For personal use only.
    [Show full text]
  • Environmental and Safety Considerations for Solar Heating and Cooling Applications
    IMBSIR 78-1532 Environmental and Safety Con- siderations for Solar Heating and Cooling Applications David Waksman John Holton Solar Criteria and Standards Program Building Economics and Regulatory Technology Division Center for Building Technology National Engineering Laboratory National Bureau of Standards Washington, D.C. 20234 September 1978 Prepared for Department of Energy Office of Conservation and Solar Applications Washington, D.C. and Department of Housing and Urban Development Division of Energy, Building Technology and Standards Washington, D.C. 20410 "OC — 1 100 . U56 tf78-1532 / m faWeffa! Sireal of Stansf&ri* MAY 1 4 1979 NBSIR 78-1532 * »r ENVIRONMENTAL AND SAFETY CON- SIDERATIONS FOR SOLAR HEATING AND COOLING APPLICATIONS David Waksman John Holton Solar Criteria and Standards Program Building Economics and Regulatory Technology Division Center for Building Technology National Engineering Laboratory National Bureau of Standards Washington, D.C. 20234 September 1978 Prepared for Department of Energy Office of Conservation and Solar Applications Washington, D.C. and Department of Housing and Urban Development Division of Energy, Building Technology and Standards Washington, D.C. 20410 ; ; . a.c,: u j\, i \ : V. - - ( X id'..' U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary Dr. Sidney Harman, Under Secretary Jordan J. Baruch, Assistant Secretary for Science and Technology NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director TABLE OF CONTENTS Page 1. INTRODUCTION 1 2. GENERAL PROVISIONS 1 3. FIRE SAFETY PROVISIONS . 2 3.1 FLAMMABLE MATERIALS 2 3.2 FIRE RESISTANCE OF BUILDING ASSEMBLIES 6 3.3 EMERGENCY ACCESS AND EGRESS 7 A. PROTECTION OF AIR AND POTABLE WATER 8 A. 1 PROTECTION OF POTABLE WATER 9 A.
    [Show full text]
  • 2009 ASHRAE Handbook—Fundamentals Covers Basic Prin- • Chapter 20, Space Air Diffusion, Has Been Completely Rewritten to Ciples and Data Used in the HVAC&R Industry
    2009 ASHRAE HANDBOOK FUNDAMENTALS I-P Edition Supported by ASHRAE Research 2009 ASHRAE® HANDBOOK FUNDAMENTALS Inch-Pound Edition American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 1791 Tullie Circle, N.E., Atlanta, GA 30329 (404) 636-8400 http://www.ashrae.org ©2009 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. All rights reserved. DEDICATED TO THE ADVANCEMENT OF THE PROFESSION AND ITS ALLIED INDUSTRIES No part of this publication may be reproduced without permission in writing from ASHRAE, except by a reviewer who may quote brief passages or reproduce illustrations in a review with appropriate credit; nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any way or by any means—electronic, photocopying, recording, or other—without permission in writing from ASHRAE. Requests for permis- sion should be submitted at www.ashrae.org/permissions. Volunteer members of ASHRAE Technical Committees and others compiled the infor- mation in this handbook, and it is generally reviewed and updated every four years. Com- ments, criticisms, and suggestions regarding the subject matter are invited. Any errors or omissions in the data should be brought to the attention of the Editor. Additions and correc- tions to Handbook volumes in print will be published in the Handbook published the year following their verification and, as soon as verified, on the ASHRAE Internet Web site. DISCLAIMER ASHRAE has compiled this publication with care, but ASHRAE has not investigated, and ASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure, design, or the like that may be described herein.
    [Show full text]
  • Humidity and Occupants Presentation
    Humidity and Occupants What the Latest in Humidity Research Means for You Presenters Matt Nowak North American Sales Manager Armstrong International Eric Brodsky, PE Director of Technology Research Products Inc. / Aprilaire / DriSteem Duncan Curd General Manager Nortec Humidity Ltd. Jeremy Wolfe National Sales & Marketing Manager CAREL USA Agenda 1. Fundamentals of Humidity • Key Terms and Definitions • How indoor humidity changes throughout the year • Where humidification matter most 2. Humidity and People • Historical Research • Impacts of moisture to the human body • Recent advances in humidity research 3. Recent Research • Microbiome Study Details • Example of Hospital Savings • Results and Recommendations 4. Humidity in Your Building • Technologies for Humidification • Cooling and Humidifying with Adiabatic Systems • Humidification with Steam • Case Studies / Installation Examples What is Humidity and How Do We Measure It? Humidity • The amount of water vapor in the air • Measured in “Absolute” or “Relative” terms Absolute Humidity • Mass of water in particular volume of air • Expressed as mass (grains/lbda or gw/kgda) Relative Humidity • Amount of water vapor in the air relative to how much it can hold at a given temperature (%) 25 20 15 Maximum Moisture Content Of Air Depends 10 5 0 On Air Temperature Grains Grains of/ Water Cubic Foot of Air 0 5 -5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 -10 100 Air Temperature (F) How Much Water Can the Air Hold? Air Heated From 10°F @ 100% RH to 70 °F 1 lb (kg) of Air Would Only Be Less Than 10% RH 35°F (2°C) 30 gr (2g/kg) The Psychrometric Chart Typical RH in Las Vegas, NV Typical Temps in Las Vegas, NV Need for Humidification Summer (July 19th) – 104F @ 10% RH = 72F @ 27.5% RH Winter (Dec.
    [Show full text]
  • New Guidance for Residential Air Cleaners- ASHRAE Journal Sep 2019
    TECHNICAL FEATURE ©ASHRAE www.ashrae.org. Used with permission from ASHRAE Journal at www.epa.gov. This article may not be copied nor distributed in either paper or digital form without ASHRAE’s permission. For more information about ASHRAE, visit www.ashrae.org. New Guidance for Residential Air Cleaners BY LEW HARRIMAN, FELLOW/LIFE MEMBER ASHRAE; BRENT STEPHENS, PH.D, MEMBER ASHRAE; TERRY BRENNAN, MEMBER ASHRAE As HVAC&R professionals, we in the ASHRAE community are sometimes asked ques- tions about residential indoor air quality (IAQ) and how to improve it. What contami- nants are most hazardous? How do I get rid of a particular smell? Should I use this air cleaner or that filter? Sadly, our friends and family generally lose patience when we helpfully suggest: “Well, it’s complicated. But just read Chapters 46, 60 and 62 in the ASHRAE Handbook—HVAC Applications, because there’s great information in there.” In general, we find that information seekers are frustrated by such helpful advice. Usually, the question is repeated (with some heat) in a form such as: “You’re the professional. Can’t you boil it down? What should I DO in my HOUSE?” Fortunately, two new resources can help you better mainstream and social media. When you get questions answer such questions. First, the ASHRAE Residential from friends and family about residential air filtration Indoor Air Quality Guide1 is a comprehensive summary of and air cleaners, you may find the U.S. Enivronmental IAQ for homes and apartments, written by our mem- Protection Agency’s recently updated publications help- ber colleagues and published by ASHRAE in 2018.
    [Show full text]
  • Solar System Design Basics
    James M. Pleasants Company, Inc. 800-365-9010 Solar System Design Basics James M. Pleasants Company www.jmpco.com 1 Availability of Solar Energy • Solar constant at mean earth-sun distance • 441 Btu/h · ft2 winter and 413.1 Btu/h · ft2 summer • Solar Insolation is total radiation earth 1. Direct Solar radiation (()88 to 95%) 2. Diffuse Solar radiation 3. Reflected Solar radiation 3 ©Copyright 2011 James M. Pleasants Company, Inc. 1 James M. Pleasants Company, Inc. 800-365-9010 2011 ASHRAE HANDBOOK HVAC Applications I-P Edition Supported by ASHRAE Research 4 CHAPTER 35 SOLAR ENERGY USE QUALITY AND QUANTITY OF SOLAR ENERGY Solar Constant …The current value of the solar constant (which is defined as the intensity of solar radiation on a surface normal to the sun’s rays, just beyond the earth’s atmosphere at the average earth-sun distance) is 433 Btu/h · ft2. Chapter 15 of the 2009 ASHRAE Handbook-Fundamentals has further information on this topic. 5 ©Copyright 2011 James M. Pleasants Company, Inc. 2 James M. Pleasants Company, Inc. 800-365-9010 413.1 Btu/h · ft2 Summer 441 Btu/h · ft2 Winter The Earth is closest to the Sun in the Winter 6 http://en.wikipedia.org/wiki/Seasons Earth’s yearly revolution around the sun Earth revolves around the sun once per year. The axis of rotation points in the same direction throughout the yearly trip. April March February May January June 23.5o July December August November September October 7 http://www.classzone.com/books/earth_science/terc/content/visualizations/es0408/es0408page01.cfm?chapter_no=visualization ©Copyright 2011 James M.
    [Show full text]
  • Building Air Intake and Exhaust Design
    CHAPTER 46 BUILDING AIR INTAKE AND EXHAUST DESIGN Exhaust Stack and Air Intake Design Strategies........................................................................... 46.1 Geometric Method for Estimating Stack Height ........................................................................... 46.5 Exhaust-To-Intake Dilution or Concentration Calculations......................................................... 46.7 Other Considerations.................................................................................................................. 46.10 UTDOOR air enters a building through its air intake to provide O ventilation air to building occupants. Likewise, building ex- haust systems remove air from a building and expel the contaminants to the atmosphere. If the intake or exhaust system is not well de- signed, contaminants from nearby outdoor sources (e.g., vehicle ex- haust, emergency generators, exhaust stacks on nearby buildings) or from the building itself (e.g., laboratory fume hood exhaust, plumb- ing vents) can enter the building before dilution. Poorly diluted con- taminants may cause odors, health impacts, and reduced indoor air quality. This chapter discusses proper design of exhaust stacks and placement of air intakes to avoid adverse air quality impacts. Chapter 24 of the 2017 ASHRAE Handbook—Fundamentals de- scribes wind and airflow patterns around buildings in greater detail. Related information can also be found in Chapters 9, 18, 33, 34, and 35 of this volume, Chapters 11 and 12 of the 2017 ASHRAE Hand- Fig. 1 Flow Recirculation Regions and Exhaust Parameters book—Fundamentals, and Chapters 29, 30, and 35 of the 2016 (Wilson 1982) ASHRAE Handbook—HVAC Systems and Equipment. of ganged stacks. In general, for a tight cluster to be considered as a 1. EXHAUST STACK AND AIR INTAKE single stack (i.e., to add stack momentums together) in dilution cal- DESIGN STRATEGIES culations, the stacks must be uncapped and nearly be touching the middle stack of the group.
    [Show full text]
  • ANSI/ASHRAE Addendum Ae to ANSI/ASHRAE Standard 62.1-2016 Ventilation for Acceptable Indoor Air Quality
    ANSI/ASHRAE Addendum ae to ANSI/ASHRAE Standard 62.1-2016 Ventilation for Acceptable Indoor Air Quality Approved by the ASHRAE Standards Committee on June 26, 2019; by the ASHRAE Board of Directors on August 1, 2019; and by the American National Standards Institute on August 26, 2019. This addendum was approved by a Standing Standard Project Committee (SSPC) for which the Standards Committee has estab- lished a documented program for regular publication of addenda or revisions, including procedures for timely, documented, con- sensus action on requests for change to any part of the standard. Instructions for how to submit a change can be found on the ASHRAE® website (https://www.ashrae.org/continuous-maintenance). The latest edition of an ASHRAE Standard may be purchased on the ASHRAE website (www.ashrae.org) or from ASHRAE Cus- tomer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: [email protected]. Fax: 678-539-2129. Telephone: 404- 636-8400 (worldwide), or toll free 1-800-527-4723 (for orders in US and Canada). For reprint permission, go to www.ashrae.org/permissions. © 2019 ASHRAE ISSN 1041-2336 © ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission. ASHRAE Standing Standard Project Committee 62.1 Cognizant TC: 4.3, Ventilation Requirements and Infiltration SPLS Liaison: Karl L. Peterman Hoy R. Bohanon, Jr.*, Chair Enrica Galasso Lisa C. Ng Jennifer A. Isenbeck*, Co-Vice Chair Elliott Gall Daniel C. Pettway* Wayne R. Thomann*, Co-Vice Chair Gregg Gress* Stephen Ray* Nick H.
    [Show full text]
  • Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs
    ANSI/ASHRAE Addendum b to ANSI/ASHRAE Standard 140-2007 ASHRAEASHRAE STANDARDSTANDARD Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs Approved by the ASHRAE Standards Committee on January 23, 2010; by the ASHRAE Board of Directors on January 27, 2010; and by the American National Standards Institute on January 28, 2010. This standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the Standards Committee has established a documented program for regular publication of addenda or revi- sions, including procedures for timely, documented, consensus action on requests for change to any part of the standard. The change submittal form, instructions, and deadlines may be obtained in electronic form from the ASHRAE Web site, http://www.ashrae.org, or in paper form from the Manager of Standards. The latest edi- tion of an ASHRAE Standard may be purchased from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: [email protected]. Fax: 404-321-5478. Telephone: 404-636-8400 (world- wide), or toll free 1-800-527-4723 (for orders in US and Canada). For reprint permission, go to www.ashrae.org/permissions. © Copyright 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ISSN 1041-2336 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. 1791 Tullie Circle NE, Atlanta, GA 30329 www.ashrae.org ASHRAE Standing Standard Project Committee 140 Cognizant TC: TC 4.7, Energy Calculations SPLS Liaison: Nadar R. Jayaraman Ronald D. Judkoff, Chair* Sean P. Kolling Joel Neymark, Vice-Chair David E.
    [Show full text]
  • Experimental Investigation of Free Convection Heat Transfer from Horizontal Cylinder to Nanofluids
    energies Article Experimental Investigation of Free Convection Heat Transfer from Horizontal Cylinder to Nanofluids Dorota Sawicka 1, Janusz T. Cie´sli´nski 2,* and Slawomir Smolen 1 1 Faculty of Nature and Engineering, J.R. Mayer–Institute for Energy Engineering, City University of Applied Sciences Bremen, Neustadtswall 30, 28199 Bremen, Germany; [email protected] (D.S.); [email protected] (S.S.) 2 Faculty of Mechanical and Ship Technology, Institute of Energy, Gda´nskUniversity of Technology, Narutowicza 11/12, 80233 Gdansk, Poland * Correspondence: [email protected] Abstract: The results of free convection heat transfer investigation from a horizontal, uniformly heated tube immersed in a nanofluid are presented. Experiments were performed with five base fluids, i.e., ethylene glycol (EG), distilled water (W) and the mixtures of EG and water with the ratios of 60/40, 50/50, 40/60 by volume, so the Rayleigh (Ra) number range was 3 × 104 ≤ Ra ≤ 1.3 × 106 and the Prandtl (Pr) number varied from 4.4 to 176. Alumina (Al2O3) nanoparticles were tested at the mass concentrations of 0.01, 0.1 and 1%. Enhancement as well as deterioration of heat transfer performance compared to the base fluids were detected depending on the composition of the nanofluid. Based on the experimental results obtained, a correlation equation that describes the dependence of the average Nusselt (Nu) number on the Ra number, Pr number and concentration of nanoparticles is proposed. Citation: Sawicka, D.; Cie´sli´nski,J.T.; Keywords: free convection; horizontal cylinder; nanofluids; correlation equation Smolen, S. Experimental Investigation of Free Convection Heat Transfer from Horizontal Cylinder to Nanofluids.
    [Show full text]
  • Humidification Done Right
    Humidification Done Right Fundamentals and Applications Presenters Nicholas Lea, P. Eng, LEED AP BD+C Global Product Manager Nortec Humidity Ltd. Matt Nowak North American Sales Manager Armstrong International Eric Brodsky, PE Director of Technology Research Products Inc. Agenda 1. Fundamentals of Humidity • Key Terms and Definitions • Humidification Applications 2. Humidification: Commercial and Industrial • Steam Solutions • Liquid Water Solutions 3. Humidification: In the Home • Residential Applications • Technology Solutions 4. Questions What is Humidity and How Do We Measure It? Humidity • The amount of water vapor in the air • Measured in “Absolute” or “Relative” terms Absolute Humidity • Mass of water in particular volume of air • Expressed as mass (grains/lbda or gw/kgda) Relative Humidity • Amount of water vapor in the air relative to how much it can hold at a given temperature (%) How Much Water Can the Air Hold? It depends on the temperature of air! 1 lb (kg) of Air 1 lb (kg) of Air 35°F (2°C) 72°F (22°C) 30 gr (2g/kg) 30 gr (2g/kg) Sensible Heating 100% RH 25% RH How Much Water Can the Air Hold? Absolute Humidity 100% RH 120 gr (8g/kg) 25% RH 30 gr (2g/kg) 35°F 72°F 120°F (2°C) (22°C) (49°C) Temperature The Psychrometric Chart Effect of Outdoor Conditions Heating Climates • High outdoor RH does not translate indoors! RH % Indoor RH% When Heated to 70°F 100 2 4 5 6 7 9 12 17 19 23 29 36 42 53 60 1 2 3 3 4 5 7 9 11 14 17 21 26 31 50 1 1 3 3 4 4 6 8 9 12 14 18 22 26 45 1 1 2 3 3 4 6 7 8 11 13 16 20 24 40 1 1 2 3 3 4 5 7 7 10
    [Show full text]
  • Position Document on Limiting Indoor Mold and Dampness in Buildings
    ASHRAE Position Document on Limiting Indoor Mold and Dampness in Buildings Approved by ASHRAE Board of Directors June 27, 2012 Reaffirmed by ASHRAE Technology Council June 23, 2021 Expires July 1, 2023 ASHRAE 1791 Tullie Circle, NE • Atlanta, Georgia 30329-2305 404-636-8400 • fax: 404-321-5478 • www.ashrae.org COMMITTEE ROSTER The ASHRAE Position Document on Limiting Indoor Mold and Dampness in Buildings was developed by the Society’s Limiting Indoor Mold and Dampness in Buildings Position Document Committee formed on December 14, 2010. Lewis G. Harriman III, Chair Mason-Grant Portsmouth, NH Carl Grimes, CIE Healthy Habitats LLC Denver, CO K. Quinn Hart, PE U.S. Air Force Panama City, FL Michael Hodgson, PhD, MD Veterans Health Administration Washington, D.C. Lan Chi Nguyen Thi, PEng. InAIR Environmental Ltd. Ottawa, ON, Canada Francis (Bud) Offermann, PE, CIH Indoor Environmental Engineering San Francisco, CA William Rose, RA University of Illinois at Urbana-Champaign Champaign, IL COGNIZANT COMMITTEE The chairperson(s) of ASHRAE’s Technical Committee 1.12 and Environmental Health Committee served as ex-officio members. Lewis G. Harriman III ASHRAE Technical Committee 1.12, Chair Mason-Grant Portsmouth, NH Jianshun (Jensen) Zhang Environmental Health Committee, Chair Syracuse University Syracuse, NY ABSTRACT Credible research and cognizant health authorities have established an association between health problems and indoor dampness. A building’s mechanical systems, its exterior enclosure, and its occupant activities all affect the amount of wetting and drying indoors. There- fore, ASHRAE takes the position that all policymakers, regulatory authorities, building profes- sionals, and building occupants should be aware that indoor dampness, mold, and microbial growth are warnings of potential problems.
    [Show full text]