[Equest-users] sources of undercooling?

[Nick Caton]

Lauren,

 

I can't offer any "typical" reasons that would sound like specific solutions based on my memory... but as you asked a general question here's my general thought-process...

 

Unmet load hours generally mean one of 3 basic things, and each of those have things to explore: 

 

o   Your heating and/or cooling loads are too high

§  Check internal loads (i.e. people/equipment)

§  Check envelope constructions and elements (i.e. walls/windows/shades)

§  Check schedules

o   Your systems are undersized

§  Check airflow CFM's for expected/entered values

§  Check hydronic GPM's for expected/entered values

§  Check any entered capacities for all components - autosizing something previously specified and re-simulating sometimes gives you a clue or eliminates a possibility...

§  Check any water and air temperature setpoints and coil delta-T's

o   Your systems are not operating correctly in the model.

§  Check operation/schedules of systems to be sure they can run when they need to

§  Heed any cautions/warnings/errors presented in your SIM ATTN and try to resolve

§  Check thermostat setpoints/throttling ranges and such

 

Much more similar advice can be found searching the mailing list archives - others have put together more specific lists you may want to peruse =)!  

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Lauren Rosenthal
Sent: Thursday, May 06, 2010 5:25 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] sources of undercooling?

 

All,

 

What are some common sources/inputs that could cause unmet load hours, especially for cooling hours?

 

Almost all of my systems are creating unmet load hours and I'm not sure what inputs could be the cause.

 

Any suggestions would be greatly appreciated.

 

Thanks,

 

____________________________________

Lauren Rosenthal

Mechanical Engineer

 

Los Angeles CA

 

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