[Equest-users] Equipment Sizing and % Hrs in Throttling Range

Eric O'Neill elo at MichaelsEngineering.com
Mon Jan 19 07:46:47 PST 2009

Like Karen mentioned, without the inp files we can't really figure out
what's going on. I don't know how you specified it in the wizard files
(because the after file doesn't have the GSHP setup) but there is one
thing I would check. In the wizard, when specifying the GSHP, check if
you have a system per zone (not floor or shell) set up. 

If not, it will set up the GSHP with a single zone controlling every
other zone, and just having the terminal reheat set up as "Heat Pump"
doesn't seem to fix the issue. So you'll find the control zone has very
few hours under heated/cooled, where as the rest of the zones under that
system will be at the control zone's mercy (if the loads are similar to
the control zone, you'll have fewer under heated/cooled hours than if
they are substantially different). 

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Mathew
Sent: Saturday, January 17, 2009 4:59 PM
To: Equest-users at lists.onebuilding.org
Subject: [Equest-users] Equipment Sizing and % Hrs in Throttling Range

All - I'm trying to resolve a gshp school system model, to reduce the 
number of hours outside of throttling range for LEED purposes. I have 
scowered multiple threads talking about sizing, throttling range, min 
air flow ratios, reverse-action TSTATs, night-setback, gshp's, etc. and 
have applied suggestions with minimal result. The only way I can take 
considerable hours out of the % not in throttling range is if I increase

sizing ratios way beyond design capacities and strip out everything that

makes the model accurately reflect design conditions.

I've attached the before and after (.pd2) files for reference, however 
results are still not seen. SS-R reports indicate hours in the 100+ load

range, but again this is going beyond manually specifying capacities and

using sizing ratios. Also to be noted, the ASHRAE baseline (Pkg Elec HP)

is also in the same range and is not responding to changes... which 
would suggest something common to both within Appendix G criteria.

Experience and opinions would be greatly appreciated.

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

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
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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.

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