Room Air Distribution
ASHRAE Technical Committee 5.3

Past TC 5.3 Sponsored Technical Program Sessions

Long Beach Meeting, June 2017 (no presentations planned for Atlanta 2019)

Sunday, June 25, 9:45 AM - 10:45 AM  Seminar 1  Psychrometrics of Chilled Beam Systems
This seminar will explain the psychrometric calculations required for the application of a chilled beam system. Additionally, the requirements for a dedicated outside air unit will be determined for areas of high wet bulb ambient conditions. Engineers have been reluctant to design or specify these types of systems due to condensation concerns within the conditioned space. This seminar presents the correct calculations for design and selection of condensation free systems. Examples of successful installations in high wet bulb areas are presented.
1. Successful Chilled Beam System Installations
Tom Rice, Member, Semco LLC, Columbia, MO
This presentation focuses on successful installations of chilled beam systems. Correct psychrometric conditions, building pressurization and control sequences are highlighted.
2. Psychrometrics of Chilled Beam Systems
Donald Larsson, Member, United States Green Building Council, Washington, DC
This presentation demonstrates the correct use of psychrometric calculations in the application of chilled beam systems for the conditioned space.
Monday, June 26, 9:45 AM - 10:45 AM  Seminar 26  Evolution of Underfloor Design and its Application for Millennial Office Spaces
This seminar discusses the evolution of underfloor system design over the last 20 years. Early design practices and challenges are discussed and how some of those challenges led to the invent of the latest systems and their application. Project related CFD results are also shared to review how the new way of designing is pushing the envelope with energy savings. The presentation also covers items that engineers need to be aware of while applying these systems. The importance of a collaborative approach is discussed to achieve the best possible integration with building structure and services.
1. Underfloor System Design Evolution
Dan Nall, AIA, Fellow ASHRAE, Syska Hennessy, New York, NY
The major challenge for design of underfloor air distribution systems is the reconciliation of comfort requirements between the interior and perimeter zones served by the system. For a variety of reasons, the past UFAD design strategy has proved less effective. Newer strategies have been proposed and applied to overcome this issue. Each of these strategies has implications for the building architecture, first cost and performance for specific weather conditions. Some strategies may even be used together. This presentation reviews each of these strategies, discusses their benefits and limitations and presents energy modeling results for the strategies for a large office project.
2. Top Five Application Considerations for Successful UFAD Systems
Jim Megerson, P.E., Member, Design Mechanical Inc., Kansas City, KS
Presentation content includes items that engineers need to be aware of so that obstacles to a successfully operating system can be avoided. UFAD systems are highly integrated with other services and more closely couple with the building structure than compared to traditional overhead mixing systems. This inherent characteristic of UFAD systems demands an integrated and collaborative approach when working on these types of projects. This seminar addresses issues that need attention and sometimes get overlooked when designers treat UFAD projects similar to overhead mixing system during design.
Tuesday, June 27, 11:00 AM - 12:30 PM  Seminar 46  Updates in the Air Distribution Systems Design Procedure: Expansion of Air Diffusion Performance Index (ADPI) Method
This session covers the history of ADPI and the recently completed RP 1546 Expansion and Updating of the Air Diffusion Performance Index Method conduct at the University of Texas. The session consists of four presentations: Background of using ADPI in diffuser selection process, Updated ADPI tables for cooling operation, Additional development of the effective draft temperature for heating, Findings from the research to ensure ventilation effectiveness in overhead heating applications and Effect of return air placement in heating applications. A preview of the updates which will be included in the ASHRAE Application Handbook Room Air Distribution Chapter is included.
1. Updates in Air Diffusion Performance Index (ADPI) Diffuser for Cooling Operation
Atila Novoselac, Ph.D., Member, University of Texas at Austin, Austin, TX
The current diffuser selection guide described in ASHRAE handbook-fundamentals provides the correlation between diffuser characteristics, such as throw length and types, and its performance to distribute supply air and thereby to optimize space air diffusion. However, the current guideline considers only five diffuser types and the range of sensible cooling loads that is up to four times larger than those we find in today’s energy efferent buildings. This presentation shows the updated ADPI-based guideline that includes 15 diffuser types at lower cooling loads, typical for today’s buildings. The new guideline shows the minimum airflow set-point for a VAV systems.
2. A New Air Diffusion Performance Index (ADPI) for Heating Operation
Shichao Liu, Ph.D., Associate Member, Center for Built Environment at UC Berkeley, Berkeley, CA
The performance of air distribution using overhead mixing diffusers is evaluated using ADPI. The ADPI methods is often used for selection of diffusers used for both cooling and heating. However, the current diffuser selection guide confines the application to only cooling mode. This presentation introduces a new ADPI for heating mode and specify the criteria of diffuser selection from the perspectives fluid dynamics and occupant thermal comfort based on ASHRAE Standard-55. The presentation covers the development of the effective draft temperature for heating applications and the resulting ADPIs curves with various diffuser types.
3. Connection between Air Diffusion Performance Index (ADPI) and Ventilation Effectiveness (EV): Effects of Diffuser Adjustment and Return Air Placement
Hideyuki Amai, University of Texas at Austin, Austin, TX
This presentation provides fundamental design data that supports optimal diffuser selection in mixing ventilation with heating and cooling operation. It shows how diffuser adjustment, room-supply air temperature differences and return air grille location impact ADPI and EV. The study points out connections between ADPI and EV and shows similarities and differences for heating and cooling operation. It presents the operation characteristic that provide good EV while maintaining acceptable ADPI. Also, it shows how diffuser adjustment may improve EV. Furthermore, the presentation shows the cases where return air location may have a significant effect on ADPI and EV.
4. The History of Air Diffusion Performance Index (ADPI) and the Results of Research Project RP 1546 Expansion and Updating of the ADPI Method
David John, P.E., Member, Stan Weaver & Co., Tampa, FL
The effective draft temperature was experimentally developed in 1949 in Sweden. This is the current equation used to calculate ADPI for cooling. In 1972 Nevins and Miller presented an ASHRAE paper which determined that boundaries for ADPI to obtain a 70% occupant comfort level. After 33 years, this method needed many updates as buildings and air distribution systems changed. The ASHRAE RP 1546 updated and confirmed the ADPI predicted comfort levels using Standard 55. It produced the effective draft temperature equation for heating. Furthermore, it developed ADPI values that can predict thermal mixing in heating.

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ALL ASHRAE committee meetings, including this TC’s meetings at the Winter and Annual Society conferences, are open to the public at no cost nor is conference registration required. Interested visitors, local chapter members, and potential new TC members are always welcome. However to attend technical program sessions sponsored by the TC will require registration and payment of any applicable fee.

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