[Bldg-sim] Title 24: natural ventilation and chilled beams

[Fred Porter]

All
Since Eric has not "corrected" Mathew, I will:
The eQuest POWERED induction unit SYSTEM (i.e. TYPE = PIU) just refers to fan-powered reHEAT boxes in VAV systems. The eQuest INDUCTION UNIT SYSTEM models an archaic system that can be made somewhat analogous to modern ACTIVE chilled beam systems by overriding some of the system defaults. However, no matter what the user specifies in the zone, this simulates constant volume airflow to all connected zones whenever the central AHU is active. 
 
The natural ventilation system keywords only apply to PSZ and related SYSTEM types, so can only be utilized in the most basic small commercial building models. And I'm fairly certain wind direction is not considered even by the more sophisticated S-G method, among other shortcomings. 
 
Fred Porter
Architectural Energy

>>> Mathew Higgins <higgins at edi-arch.com> 12/23/2008 12:05 PM >>>
Eric, please correct me if I'm wrong but I though a chilled beam was an 
induction unit; and eQuest has both powered and non-powered induction 
units. Also, if you look at the HVAC units you input there is an Outdoor 
Air tab that will let you specify either an Air Change Rate or 
Sherman-Grimsrud Method (based on wind) for Natural Ventilation. Either 
method requires the creation of schedules, but I've found both to be 
effective.

Matthew Higgins, LEED AP + ASHRAE-HPBD
Technical Specialist
Environmental Dynamics, Inc.
Architecture and Sustainability Consulting Services
505.242.2851

Any data provided by the Consultant, verbal or written, are to be considered opinions of building energy and/or daylight performance. The Client understands that the Consultant has no control of occupant habits, equipment or material performance or characteristics, site or climate conditions or the Contractor's method of assembly, and that the Consultant's opinions regarding building energy/daylight performance are made on the basis of the Consultant's professional judgment and experience. The Consultant makes no warranty, express or implied, that the energy/daylight performance of the building will not vary from the Consultant's opinion of building energy/daylight performance.

Eric Shadd wrote:

> Since eQUEST/DOE2.2 can't don't have natural ventilation or chilled 
> beam systems, how are these handled for Title 24 compliance?
>  
> Regards,
> Eric Shadd, PE
> Project Manager, Energy Analysis Services
> Architectural Energy Corporation
> 142 Minna Street
> San Francisco, CA  94105
> PH:  415-970-6511
> FX:  415-957-1381
>
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