Presentations

ASHRAE Distinguished Lectures Other Lectures

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ASHRAE Distinguished Lectures

Analysis of Airflow Patterns and Flow Path of Airborne Contaminants

Recent COVID-10 pandemic necessitates an increased need for understanding the room airflow patterns and its role in containing and spreading of airborne contaminants. With air being the primary carrier of heat, moisture, and airborne contaminants the flow path of supply air plays an important role in determining the flow path of airborne contaminants in indoor facilities. This course covers the basics of airflow and particle dynamics and demonstrates how the supply air flow paths, induced air flow paths, and exhaust grille placement can work collaboratively to establish protective and effective contaminant control in a typical patient room. Several studies indicate that the design of a ventilation system and the resulting airflow patterns play a more important role in controlling the flow path of airborne contaminants than just the supply airflow rate or air changes per hour (ACH) alone. This case study evaluates the impact of supply and return locations on the airflow patterns and temperature distribution along with the resulting thermal comfort of occupants. Probable flow path of airborne particulates in a typical patient room using Computational Fluid Dynamics (CFD) simulations are demonstrated. Insightful airflow animations will show the movement of airborne particles for various applications displaying the importance of HVAC design including the locations of supply and exhaust grilles. The course provides valuable insights to HVAC design engineers, facility managers, infection prevention personnel, and building owners regarding the role of airflow patterns and resulting flow path of airborne contaminants.

Application of Computational Fluid Dynamics (CFD) for Built Environment (AIA and GBCI approved)

Air is the primary carrier of heat, moisture, and contaminants in and around built environments. Airflow patterns determine the distribution of temperature, contaminant level, and importantly air quality and thermal comfort of occupants. The HVAC design risk due to poor airflow management is often realized after commissioning and occupancy. Sometimes it is too late to mitigate the issues related to poor airflow management. This presentation will show how Computational Fluid Dynamics (CFD) can help in identifying such risks at early stages in the design and help optimize the HVAC designs for effective and energy efficient performance. After providing a brief introduction to CFD, this presentation with the help of several case studies will show applications of CFD for a wide variety of scenarios involving displacement ventilation, active and passive chilled beams, airflow patterns in enclosed spaces, radiant heating and cooling, smoke propagation in atria, clean rooms, data centers, patient rooms, laboratories, plume dispersion from cooling towers, and several other similar applications to built environment.

Airflow Management for Cleanroom Facilities (AIA and GBCI approved)

Clean spaces are developed for a variety of applications including healthcare, aerospace, microelectronics, pharmaceutical, food and beverages. The main goal of cleanroom application is to maintain high level of cleanliness in the spaces to minimize any cross contamination. Air is the primary carrier of heat, moisture, and contaminants in cleanroom facilities. The flow path of supply air plays an important role in determining the air velocities, air temperatures, particle concentration, and flow path of airborne particles. These factors in turn determine the level of cleanliness and distribution of contaminants in the space. This presentation will first cover basics of cleanroom classifications, and sources of contaminants, and then, will focus on the importance of HVAC configuration on airflow distribution and resulting flow path of airborne particles in cleanroom that affect the contaminant removal effectives. In addition, this presentation will also cover role of Air Changes per Hour (ACH), demand control ventilation, cleanroom airlocks, and dynamics of laminar diffusers in cleanrooms.

Airflow Management for Healthcare Facilities (AIA and GBCI approved)

Air is the primary carrier of heat, moisture, and contaminants in health care facilities such as patient rooms, isolation rooms, and operating rooms. The flow path of supply air plays an important role in determining the air velocities, air temperatures, concentration of contaminants, and path of airborne pathogens in these spaces. These factors in turn determine thermal comfort of occupants, indoor air quality, and potential for transmission of airborne pathogens. This presentation will focus on the importance of HVAC configuration on airflow distribution and flow path of airborne contaminants in patient rooms and operating rooms. In addition, this presentation will cover the applications of active chilled beams, radiant heating and cooling, and displacement ventilation in patient rooms.

Airflow Management for Laboratory Facilities (AIA and GBCI approved)

Air is the primary carrier of heat, moisture, and contaminants in laboratory facilities. The flow path of supply air plays an important role in determining the air velocities, air temperatures, concentration of contaminants, and path of contaminants in laboratories. Often high airflow rates or air change rates per hour (ACH) for laboratory spaces are specified to cover the risk of chemical exposure. Although high supply airflow rates can reduce the overall concentration of contaminants it may not ensure uniformity of concentrations at a low diluted level. Importantly, locations of high concentration, especially those in the breathing zone of occupants can pose potentially higher exposure risk. This presentation will focus on the importance of HVAC configuration on airflow distribution and flow path of contaminants in laboratories. In addition, this presentation will cover basics of air ventilation for laboratories and flow dynamics of fume hoods.

Stratified Air Ventilation Systems (AIA and GBCI approved)

Displacement ventilation systems and underfloor air distribution system (UFAD) which are also referred as “stratified air distribution systems” work on the principle of thermal buoyancy – hot air due to lower density rises above the cold air. Stratified distribution systems are becoming popular due to their ability to provide better indoor air quality with low energy demand. This presentation will cover the basics of stratified air distribution systems and discuss various applications showing how design and operational parameters can affect the airflow patterns and temperature distribution and resulting thermal comfort of occupants in the space.

Airflow Management Best Practices for Data Centers (AIA and GBCI approved)

Airflow management within data centers is crucial for proper cooling and energy efficiency of data centers. Proper selection as well as proper placement of various data center equipment such as CRACs, perforated tiles, and racks play an important role in airflow distribution and cooling performance of data centers. This presentation will focus on basics of data center cooling and principles of air movement in data centers with a wide variety of examples involving raised floor and flat floor data rooms, air leakages through server cabinets and containment systems, and role of rack thermal mass during power shutdown. This presentation will also discuss plume dispersion in the equipment yard around the data centers and optimum placement of air cooled chillers.

Design and Analysis of Natural Ventilation Systems (AIA and GBCI approved)

A good design of a natural ventilation system maintains harmony between the local climates, space sensible heat loads, and the design of operable openings (windows). Poorly designed systems can perform miserably even in the best climatic conditions. Several factors such as building orientation, building massing, effective opening areas and their locations, relative height differences, internal heat loads, furniture and seating arrangement within the occupied spaces can affect the performance of natural ventilation systems. This presentation will discuss basics of natural ventilation and with the help of case studies demonstrate how basic analyses can help predict number of hot and comfortable hours for occupants and how to optimize the performance of natural ventilation designs.

Basics of Air Change Rates (ACH): Facts versus Fiction (AIA and GBCI approved)

Air Changes per Hour (ACH) is often specified in ASHRAE standards, codes, design guidelines, and handbooks for required ventilation rate. Examples of such spaces are patient rooms, operating room, bathrooms, cleanroom, and laboratories. This presentation will systematically demonstrate the validity of popular notions regarding the ACH. The role of space volume in controlling and distributing the contaminant in the space will be discussed. This presentation will further demonstrate whether ACH can be a sole criterion for effective ventilation of critical spaces using the examples for patient room, hospital operating room, laboratory spaces, and cleanroom. A new concept for analyzing ventilation effectiveness for these spaces will be introduced to design and optimize the HVAC layout for healthcare, laboratory, and cleanroom facilities. In addition, a role of demand control ventilation in minimizing the ACH will be discussed. This lecture will provide valuable insights to architects, design engineers, and facilities managers into the design and operation of critical facilities.

Compassion in HVAC Designs

ASHRAE’s mission is “to serve humanity by advancing the arts and sciences of heating, ventilation, air conditioning, refrigeration and their allied fields” and the vison is “a healthy and sustainable built environment for all.” The question is how can we achieve this mission and vision? Can “human-centric” HVAC designs be created by simply following the building codes and standards? Can energy efficient buildings be also effective in creating healthy, comfortable, and productive indoor environments? In addition to these questions this presentation will answer why compassion is important during the design process to create “human-centric” HVAC designs. This presentation will demonstrate how advanced analysis techniques can help achieve ASHRAE’s mission.

Other Lectures

Basics of Computational Fluid Dynamics (CFD) – Half Day Training

Air is the primary carrier of heat, moisture, and contaminants in indoor spaces. Therefore, proper airflow management is the key for effective ventilation of built environment. The design risk due to poor airflow management is often realized after commissioning and occupancy. Sometimes it is too late to mitigate the issues due to poor airflow management and modify the lab HVAC design. The science of Computational Fluid Dynamics (CFD) can help in identifying such risks at early stages in the design and help optimize the lab HVAC designs for effective and energy efficient performance. However, beyond the colorful pictures, there is a lack of understanding about the basics, benefits, limitations, and pitfalls of CFD technology. This training session will provide a brief overview of nuts and bolts of CFD for owners, architects, and design engineers and what to watch in the CFD simulations beyond colorful pictures. This lecture will help attendees separate substance and value out of CFD simulations and will discuss a few selected applications of CFD for HVAC design analysis and optimization.

ASHRAE Learning Institute: FREE Webinar

Analysis of Airflow Patterns and Flow Path of Airborne Contaminants
Recent COVID-19 pandemic necessitates an increased need for understanding the room airflow patterns and its role in containing and spreading of airborne contaminants. With air being the primary carrier of heat, moisture, and airborne contaminants the flow path of supply air plays an important role in determining the flow path of airborne contaminants in indoor facilities. This course covers the basics of airflow and particle dynamics and demonstrates how the supply air flow paths, induced air flow paths, and exhaust grille placement can work collaboratively to establish protective and effective contaminant control in a typical patient room. Several studies indicate that the design of a ventilation system and the resulting airflow patterns play a more important role in controlling the flow path of airborne contaminants than just the supply airflow rate or air changes per hour (ACH) alone. This case study evaluates the impact of supply and return locations on the airflow patterns and temperature distribution along with the resulting thermal comfort of occupants. Probable flow path of airborne particulates in a typical patient room using Computational Fluid Dynamics (CFD) simulations are demonstrated. Insightful airflow animations will show the movement of airborne particles for various applications displaying the importance of HVAC design including the locations of supply and exhaust grilles. The course provides valuable insights to HVAC design engineers, facility managers, infection prevention personnel, and building owners regarding the role of airflow patterns and resulting flow path of airborne contaminants.

Watch Recording

Keynote Address at Roberts Gordon Sales Meeting

FREE Master Class by TIPS: The Infection Prevention Strategy

Airflow Patterns and Flow Path of Airborne Particulates
This FREE Master Class is brought to you by TIPS: The Infection Prevention Strategy
Hospital-acquired infections has been persistent in hospitals and airborne transmission plays a role in many nosocomial infections. The flow path of supply air plays an important role in determining the flow path of airborne pathogens in these spaces. The airflow distribution also determines the thermal comfort of occupants, indoor air quality, distribution of surface contamination, and potential for transmission of airborne pathogens in a room. Several studies indicate that the design of a ventilation system and the resulting airflow patterns play a more important role in controlling the flow path of contaminants than just the supply airflow rate or air changes per hour (ACH) alone. This case study evaluates the impact of supply and return locations on the airflow patterns and temperature distribution along with the resulting thermal comfort of occupants, and probable flow path of airborne pathogens in a typical patient room using Computational Fluid Dynamics (CFD) simulations. This study demonstrates that the supply air flow paths, induced air flow paths, and exhaust grille placement can work collaboratively to establish protective and effective contaminant control. The presentation with the help of insightful airflow animations will show the movement of airborne particles in a patient room and will demonstrate the important of locations supply and exhaust grills. This presentation will provide valuable insights to healthcare facilities managers, owners and design engineers in designing the HVAC systems for patient rooms.

Watch Recording

I2SL Webinar: Air Change Rate (ACR) or HVAC Configuration—Which Makes Labs Safe?

Often high airflow rates or air change rates per hour (ACH) for laboratory spaces are presumed to cover the risk of chemical exposure. Previous analysis indicated that high ACH does not necessarily create diluted indoor environment at all the time for all the occupants. This presentation with the help of Computational Fluid Dynamics (CFD) analysis will demonstrate the effect of HVAC configuration on the ventilation effectiveness of HVAC system. This study investigates the impact of number and location of exhaust grilles on the flow path of contaminants and the resulting transient and spatial distribution of contaminant concentrations in a typical lab. The ventilation effectiveness of the HVAC system is analyzed with the help of two non-dimensional indices. The analysis results are presented with insightful animations showing the progression and movement of contaminant cloud in the space.

https://www.i2sl.org/training/2020/webinar_march19.html

I2SL Webinar: Do High Air Change Rates Make Labs Safe?

This study investigates the impact of ACH on the flow path of contaminants and the resulting transient and spatial distribution of contaminant concentrations in a typical lab. A total of four ACH levels varying from 4 to 10 are analyzed for the same generation rate of the contaminant and for the same layout of the ventilation system. Time varying concentration levels are predicted at the face level of three occupants located at three different locations in the lab as well as in the exhaust duct. Based on these concentrations the time varying chemical exposure (dose) for each occupant is calculated. This analysis shows depending on the position of the occupant relative to the source of contaminant and the location of exhaust grills the exposure levels can vary. High ACH does not necessarily create diluted indoor environment at all the time for all the occupants. The analysis results are presented with insightful animations showing the progression and movement of contaminant cloud in the space.

https://www.i2sl.org/training/2019/webinar_apr18.html

I2SL Webinar: Applications of Computational Fluid Dynamics for HVAC Design Optimization

Air is the primary carrier of heat, moisture, and contaminants in laboratory spaces. Therefore, proper airflow management is the key for effective laboratory ventilation. The design risk that can cause poor airflow management in laboratory spaces is often realized after commissioning and occupancy. However, computational fluid dynamics (CFD) can help identify risks during the early stages of designing a laboratory and help optimize an effective, energy-efficient HVAC system. This presentation will explain CFD technology and how to use it. It will also examine several case studies of laboratories, clean rooms, data centers, patient rooms, operating rooms, and office spaces to demonstrate how CFD analyses helped identify the risks and optimize the HVAC designs.

https://www.i2sl.org/training/2018/webinar_feb15.html

What lecture attendees say…

“Very practical and informative, beneficial for my job, Good talk with relevant examples” , “Very experienced presenter with good sense of humor. I have Better understanding of the topic after attending the lecture”
Kuala Lumpur, Malaysia ASHRAE Chapter

“Great sense of humor and enthusiasm”, “Great presenter, very engaging”, “Highly recommended speaker”
Tucson, Arizona ASHRAE Chapter

“All HVAC engineers need to see this presentation to better understand Physics of airlow”, “Dr. Khankari was very entertaining, stated importance of the topic and demonstrated examples throughout the industry. He was great with the audience.”, “Best Speaker. Great and organized presentation. Good depth and information.”
Tampa, Florida ASHRAE Chapter

“I am a non-technical person but Dr. Khankari presented a very technical topic in an easy to understand way.”,  “Very dynamic speaker – fun to listen to – made a complicated topic very understandable.”
Detroit, Michigan ASHRAE Chapter

Request a lecture by Dr. Khankari

Lectures on applications of CFD for building HVAC, thermal comfort, and indoor air quality.