Humidity and Occupants Presentation
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Preparing HVAC Systems Before Reoccupying a Building by JOHN MCCARTHY, SC.D., C.I.H., MEMBER ASHRAE; KEVIN COGHLAN, C.I.H
TECHNICAL FEATURE This article was published in ASHRAE Journal, January 2021. Copyright 2020 ASHRAE. Posted at www.ashrae.org. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about ASHRAE Journal, visit www.ashrae.org. Preparing HVAC Systems Before Reoccupying A Building BY JOHN MCCARTHY, SC.D., C.I.H., MEMBER ASHRAE; KEVIN COGHLAN, C.I.H. As states across the U.S. roll out new phases of reopening and ease social distanc- ing restrictions instituted to “flatten the curve” of infection from SARS-CoV-2 (the virus that causes COVID-19), commercial building owners and facility manag- ers are seeking direction in preparing their spaces to a return to near-normal levels of occupancy. World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC) recommendations have focused on “de-densifying” spaces and disinfection of surfaces, while the ASHRAE Epidemic Task Force’s comprehen- sive Building Readiness guidance addresses strategies for preparing HVAC systems for buildings reopening after COVID-19 closures.1 Still, facility engineers have been wondering whether disinfecting their facility’s HVAC system is a further protective step to take to prepare for reopening—and about what else they should do. While no blanket answer exists to fit every scenario reduced loads or turned off as an energy-saving and every building type, the current science2 indicates measure. that, in general, disinfection of mechanical systems is not likely to be necessary. However, that doesn’t mean How SARS-CoV-2 Transmission Impacts Disinfection there isn’t work to be done—or risks to address before Recommendations reopening or expanding the number of occupants To understand why HVAC system disinfection may not in the space. -
Position Document on Resiliency in the Built Environment
ASHRAE and CIBSE Position Document on Resiliency in the Built Environment Approved by ASHRAE Board of Directors June 26, 2019 Approved by the CIBSE Board July 11, 2019 Expires June 26, 2022 © 2019 ASHRAE and CIBSE ASHRAE • 1791 Tullie Circle, NE • Atlanta, Georgia 30329-2305 • 404-636-8400 • www.ashrae.org CIBSE • 222, Balham High Road • London SW12 9BS • 0208 675 5211 • www.cibse.org © 2019 ASHRAE and CIBSE. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without copyright holders' prior written permission. COMMITTEE ROSTER The ASHRAE and CIBSE Position Document on Resiliency in the Built Environment was developed by ASHRAE’s Resiliency in the Built Environment Position Document Committee formed on October 10, 2017, with David Under- wood as its chair. David Underwood Andrew Persily Retired NIST Oakville, ON, Canada Gaithersburg, MD, USA Scott Campbell Thomas Phoenix National Ready Mixed Concrete Association Clark Patterson Lee Milwaukee, WI, USA Greensboro, NC, USA Hywel Davies CIBSE Paul Torcellini London, United Kingdom Eastford, CT, USA Bill McQuade Chandra Sekhar AHRI National University of Singapore Arlington, VA, USA Singapore, Singapore The CIBSE Technology Committee was responsible for oversight of the CIBSE contribution to this position docu- ment. Cognizant Committees The chairperson of ASHRAE Technical Committee 2.10, Resilience and Security, also served as an ex-officio member: Jason DeGraw Arvada, CO, USA 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. © 2019 ASHRAE and CIBSE. For personal use only. -
Investigating Applicability of Evaporative Cooling Systems for Thermal Comfort of Poultry Birds in Pakistan
applied sciences Article Investigating Applicability of Evaporative Cooling Systems for Thermal Comfort of Poultry Birds in Pakistan Hafiz M. U. Raza 1, Hadeed Ashraf 1, Khawar Shahzad 1, Muhammad Sultan 1,* , Takahiko Miyazaki 2,3, Muhammad Usman 4,* , Redmond R. Shamshiri 5 , Yuguang Zhou 6 and Riaz Ahmad 6 1 Department of Agricultural Engineering, Bahauddin Zakariya University, Bosan Road, Multan 60800, Pakistan; [email protected] (H.M.U.R.); [email protected] (H.A.); [email protected] (K.S.) 2 Faculty of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga-shi, Fukuoka 816-8580, Japan; [email protected] 3 International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan 4 Institute for Water Resources and Water Supply, Hamburg University of Technology, Am Schwarzenberg-Campus 3, 20173 Hamburg, Germany 5 Leibniz Institute for Agricultural Engineering and Bioeconomy, Max-Eyth-Allee 100, 14469 Potsdam-Bornim, Germany; [email protected] 6 Bioenergy and Environment Science & Technology Laboratory, College of Engineering, China Agricultural University, Beijing 100083, China; [email protected] (Y.Z.); [email protected] (R.A.) * Correspondence: [email protected] (M.S.); [email protected] (M.U.); Tel.: +92-333-610-8888 (M.S.); Fax: +92-61-9210298 (M.S.) Received: 4 June 2020; Accepted: 24 June 2020; Published: 28 June 2020 Abstract: In the 21st century, the poultry sector is a vital concern for the developing economies including Pakistan. The summer conditions of the city of Multan (Pakistan) are not comfortable for poultry birds. -
Thermal Science Cooling Tower Performance Vs. Relative Humidity
thermal science Cooling Tower Performance vs. Relative Humidity BASIC THEORY AND PRACTICE Total Heat Exchange A mechanical draft cooling tower is a specialized heat exchanger G = mass rate of dry air [lb/min] in which two fluids (air and water) are in direct contact with each L = mass rate of circulating water [lb/min] other to induce the transfer of heat. Le = mass rate of evaporated water [lb/min] THW = temperature of hot water entering tower [°F] Ignoring any negligible amount of sensible heat exchange that TCW = temperature of cold water leaving tower [°F] hin = enthalpy of air entering [Btu/lb/dry air] may occur through the walls (casing) of the cooling tower, the heat hout = enthalpy of air leaving [Btu/lb/dry air] gained by the air must equal the heat lost by the water. This is Cp = specific heat of water = 4.18 [Btu/lb-°F] an enthalpy driven process. Enthalpy is the internal energy plus Win = humidity ratio of air entering [lb water/lb dry air] the product of pressure and volume. When a process occurs at Wout = humidity ratio of air leaving [lb water/lb dry air] constant pressure (atmospheric for cooling towers), the heat In order to know how much heat the air flowing through a cooling absorbed in the air is directly correlated to the change in enthalpy. tower can absorb, the enthalpy of the air entering the tower must This is shown in Equation 1. be known. This is shown on the psychrometric chart Figure 1. G (hout - hin) = L x Cp (THW - 32°) - Cp (L - Le)(TCW - 32°) (1) The lines of constant enthalpy are close to parallel to the lines of constant wet bulb. -
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. -
Recommended Qualification Test Procedure for Solar Absorber.Pdf
Date: 2004-09-10 Editor Bo Carlsson1 IEA Solar Heating and Cooling Program Task 27 Performance of Solar Façade Components Project: Service life prediction tools for Solar Collectors Recommended qualification test procedure for solar absorber surface durability 1 Address: SP Swedish National Testing and Research Institute, P.O.Box 857, SE-50115 Borås, e-mail: [email protected] Contents Page Foreword.............................................................................................................................................................iv Introduktion .........................................................................................................................................................v 1 Scope ......................................................................................................................................................1 2 Normative references ............................................................................................................................1 3 Terms and definitions ...........................................................................................................................2 4 Requirements and classification..........................................................................................................3 5 Test methods for assessing material properties as measure of absorber performance...............4 5.1 Sampling and preparation of test specimens.....................................................................................4 -
Evaluation of the Effect of Relative Humidity of Air on the Coefficients of Critical Flow Venturi Nozzles
Evaluation of the Effect of Relative Humidity of Air on the Coefficients of Critical Flow Venturi Nozzles K. Chahine and M. Ballico National Measurement Institute, Australia P O Box 264, Lindfield, NSW 2070, Australia [email protected] Abstract atmospheric pressures. To establish stable sonic conditions in the nozzle, the down-stream end of the nozzle is usually connected to a high-capacity vacuum At NMIA, volumetric standards such as Brooks pump, with the up-stream end connected to the meter- or bell provers are used to calibrate critical flow Venturi under-test. During calibration the test-flowmeter draws nozzles or “sonic nozzles”. These nozzles, which are air from the laboratory at or near atmospheric pressures extremely stable, are used by both NMIA and Australian and temperature, and with relative humidity varying accredited laboratories to establish continuous flows for between 40% and 60%. The mass flowrate produced by the calibration of gas flow meters. For operational the nozzles is calculated based on the calibrated values of reasons, sonic nozzles are generally calibrated using dry the nozzle coefficient, the measured up-stream pressure air but later used with standard atmospheric air at various and the density calculated from the air temperature, humidity levels either drawn or blown through the meter- pressure and humidity [2]. under-test. Although the accepted theoretical calculations for determining the mass flow through a sonic nozzle At present, any effect of the relative humidity on the incorporate corrections for the resulting change in air nozzle coefficients is considered as negligible, as various density, as laboratories seek to reduce uncertainties the authors have estimated the systematic error at 0.02% for validity of this assumption warrants further examination. -
Psychrometrics Outline
Psychrometrics Outline • What is psychrometrics? • Psychrometrics in daily life and food industry • Psychrometric chart – Dry bulb temperature, wet bulb temperature, absolute humidity, relative humidity, specific volume, enthalpy – Dew point temperature • Mixing two streams of air • Heating of air and using it to dry a product 2 Psychrometrics • Psychrometrics is the study of properties of mixtures of air and water vapor • Water vapor – Superheated steam (unsaturated steam) at low pressure – Superheated steam tables are on page 817 of textbook – Properties of dry air are on page 818 of textbook – Psychrometric charts are on page 819 & 820 of textbook • What are these properties of interest and why do we need to know these properties? 3 Psychrometrics in Daily Life • Sea breeze and land breeze – When and why do we get them? • How do thunderstorms, hurricanes, and tornadoes form? • What are dew, fog, mist, and frost and when do they form? • When and why does the windshield of a car fog up? – How do you de-fog it? Is it better to blow hot air or cold air? Why? • Why do you feel dry in a heated room? – Is the moisture content of hot air lower than that of cold air? • How does a fan provide relief from sweating? • How does an air conditioner provide relief from sweating? • When does a soda can “sweat”? • When and why do we “see” our breath? • Do sailboats perform better at high or low relative humidity? Key factors: Temperature, Pressure, and Moisture Content of Air 4 Do Sailboats Perform Better at low or High RH? • Does dry air or moist air provide more thrust against the sail? • Which is denser – humid air or dry air? – Avogadro’s law: At the same temperature and pressure, the no. -
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. -
Model 1830, 1850 & 1850W Dehumidifier Owner's Manual
Model 1830, 1850 & 1850W Dehumidifier Owner’s Manual PLEASE LEAVE THIS MANUAL WITH THE HOMEOWNER Installed by: _________________________________ Installer Phone: _______________________ Date Installed: _______________ ON/OFF button Up/Down Dehumidifer Control Outlet used to turn buttons used to dehumidifier on change humidity and off setting MODE button used for optional ventilation feature Inlet Filter Access Drain Power Door Switch 90-1874 WHOLE HOME Dehumidification The Aprilaire® Dehumidifier controls the humidity level in your entire home. A powerful blower inside the dehumidifier draws air into the cabinet, filters the air and removes moisture, then discharges the dry air into the HVAC system or dedicated area of the home. Inside the cabinet, a sealed refrigeration system removes moisture by moving the air through a series of tubes and fins that are kept colder than the dew point of the incoming air. The dew point is the temperature at which moisture in the air will condense, much like what occurs on the outside of a cold glass on a hot summer day. The condensed moisture drips into the dehumidifier drain pan to a drain tube routed to the nearest floor drain or condensate pump. After the moisture is removed, the air moves through a second coil where it is reheated before being sent back into the home. The air leaving the dehumidifier will be warmer and drier than the air entering the dehumidifier. SETTING THE DESIRED HUMIDITY LEVEL The dehumidifier on-board control will display the humidity setting when not running, and ENERGY SavinGS TIPS displays the measured humidity when running. Energy Savings Tip #1: Adjust the humidity setting to be as high as is comfortable to reduce dehumidifier run time. -
Factors Affecting Indoor Air Quality
Factors Affecting Indoor Air Quality The indoor environment in any building the categories that follow. The examples is a result of the interaction between the given for each category are not intended to site, climate, building system (original be a complete list. 2 design and later modifications in the Sources Outside Building structure and mechanical systems), con- struction techniques, contaminant sources Contaminated outdoor air (building materials and furnishings, n pollen, dust, fungal spores moisture, processes and activities within the n industrial pollutants building, and outdoor sources), and n general vehicle exhaust building occupants. Emissions from nearby sources The following four elements are involved n exhaust from vehicles on nearby roads Four elements— in the development of indoor air quality or in parking lots, or garages sources, the HVAC n loading docks problems: system, pollutant n odors from dumpsters Source: there is a source of contamination pathways, and or discomfort indoors, outdoors, or within n re-entrained (drawn back into the occupants—are the mechanical systems of the building. building) exhaust from the building itself or from neighboring buildings involved in the HVAC: the HVAC system is not able to n unsanitary debris near the outdoor air development of IAQ control existing air contaminants and ensure intake thermal comfort (temperature and humidity problems. conditions that are comfortable for most Soil gas occupants). n radon n leakage from underground fuel tanks Pathways: one or more pollutant pathways n contaminants from previous uses of the connect the pollutant source to the occu- site (e.g., landfills) pants and a driving force exists to move n pesticides pollutants along the pathway(s). -
ANSI/ASHRAE/ACCA Standard 180-2018
ANSI/ASHRAE/ACCA Standard 180-2018 (Supersedes ANSI/ASHRAE/ACCA Standard 180-2012) Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems Approved by ASHRAE on June 11, 2018; by the Air Conditioning Contractors of America on May 13, 2018; and by the American National Standards Institute on June 11, 2018. ASHRAE® Standards are scheduled to be updated on a five-year cycle; the date following the Standard number is the year of ASHRAE approval. The latest edition of an ASHRAE Standard may be purchased on the ASHRAE website (www.ashrae.org) or from ASHRAE Customer 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. © 2018 ASHRAE and ACCA® ISSN 1041-2336 ASHRAE Standard Project Committee 180 Lead Cognizant TC: 7.3, Operation and Maintenance Management Co-Cognizant TCs: 2.4, Particulate Air Contaminants and Particulate Contaminant Removal Equipment; and TC 9.8, Large Building Air-Conditioning Applications SPLS Liaison: R. Lee Millies, Jr. Thomas L. Paxson*, Chair Kristin H. Heinemeier* Heather L. Platt* Donald R. Langston*, Vice-Chair Donald C. Herrmann Donald Prather* Richard A. Danks*, Secretary Peter C. Jacobs* Gregg A. Ray* Hywel Davies Michael J. Lawing* George Rodriguez* Bill R. Benito* Benjamin E. Lipscomb Dale T. Rossi* Michael Blazey Phil London* Robert J. Roth Glenn Friedman* Phil Maybee* Jeff O. Sturgeon* Michael W. Gallagher Marc Newman* John Warfield * Denotes members of voting status when the document was approved for publication ACCA–EI Standards Task Team 2018–2019 Phil Forner, Chair Warren Lupson Matt Todd Dave Galbreath, Vice-Chair Raymond Granderson Brent Ursenbach Danny Halel, Secretary Timothy Offord Tom Jackson Joe Pacella ASHRAE STANDARDS COMMITTEE 2017–2018 Steven J.