Overview of Integrating Dedicated Outdoor Air Systems with Parallel Systems

1. A/E Environment PSU Overview of IntegratingDedicated Outdoor AirSystems with Parallel Systems Stanley A. Mumma, Ph.D., P.E. Professor of Architectural Engineering College of Engineering Penn State University @ University Park, PA Building Thermal and Mechanical Systems Laboratory

2. Presentation Outline • Introduction and Objective of this Presentation • Migration Path to a Dedicated OA System • Achieving Dry and Cool OA Economically • Selecting the OA Supply air Conditions • Meeting the Space Sensible Loads with a Parallel System • Integration of the thermal and Fire Suppression Transport Systems

3. Presentation Objective • Trace the Migration Path to the Dedicated OA Paradigm • Give an Overview Of Integrating Dedicated OA Systems with Parallel Terminal Cooling Systems To Show how the Other Papers in this Symposium Fit Together

4. The Migration Path toDedicated OA Systems • Ten years of Research and a Dozen Publications, Capped with a 1998 paper that analytically extended the multiple spaces concept of Std. 62 to include: Infiltration, Exfiltration/Exhaust, Interzonal transfer, and Short Circuit paths. • Conclusion, very difficult to verify that Std 62 can or has been met with an all air system. Is a Paradigm shift required?

5. Design Tool DevelopmentPeer Reviewer Comment • Each separate zone in a building is characterized by 51 variables, 49 of which are time dependent. • The time dependent variables are not known at design, much less in real time. • Reject tool development since of little value to the profession • Supports the earlier conclusion that it is very difficult to verify that an all-air system has met Std. 62.

6. The Dedicated OA Concept,the new OA paradigm! • Basic concept is to deliver conditioned OA to every space and occupant of the building. • Extension: Use the OA to remove all of the space latent load (primarily from occupants who receive a prescribed flow rate of OA). • By Decoupling the latent and sensible space loads, great flexibility in meeting the parallel sensible loads is realized!

7. The Paradigm Illustrated. High Aspiration Diffuser 20-30% less OA, Cool/Dry Supply DOAS Unit W/ Energy Recovery Building With Sensible and Latent cooling decoupled Parallel Sensible Cooling System

8. DOAS Duty • Low outside DPT: Heat or Cool the OA as necessary, and humidify if necessary • High outside DPT: Dehumidification to meet all space latent loads, and reheat if necessary • Dehumidification (Desiccants Not A topic in this symposium) • Details Topic of Paper #2.

9. Considerations when Selecting the Supply air Conditions • Low Supply air DBT reduces the load on the Parallel System (and 1st cost), but may increase terminal reheat energy use. • Low Supply air DPT reduces the space DPT, allowing the parallel system to operate at lower temp. (higher flux, smaller size, <$) without condensation. • Details subject of Paper #3.

10. Parallel Sensible Cooling System Options, operating with dry surfaces • All air VAV System • Unitary Equipment • Fan Coils • Ceiling Radiant Cooling Panels, (i.e. Chilled Ceiling). This is the subject of paper #5.

11. Functional Integration of the Thermal and Fire Suppression Transport Systems • With the Latent Load decoupled from the sensible load, the parallel system could use the uninsulated fire suppression sprinkler piping. • Is it possible, practical, legal? • Paper #4 will address NFPA, trade jurisdiction, economic, and practical issues.

12. Conclusion, and Basic Pillars of the new Paradigm • Meet ASHRAE Std. 62 with a DOAS. • Decouple the space sensible and latent loads with the DOAS. • Integrate the parallel sensible cooling equipment thermal transport system with the fire suppression system