[Bldg-sim] differences between energy simulations programs

[Clark Denson]

The way I understand it, the effect of thermal mass is all in how the
heating/cooling loads are calculated.  TRACE is unique from many other
programs in that the user can choose the heating/cooling load
methodology that will be used.  Depending on your choice, thermal mass
will be calculated differently.  Most incorporate some kind of Transfer
Function Method (TFM), and each method is based on calculations and
algorithms from ASHRAE publications such as the 1972, 1985, and 2001
ASHRAE Fundamentals Handbooks, ASHRAE Research Project #359, and the
ASHRAE Toolkit for Building Load Calculations.

So the question of "What are the differences between TRACE and Energy
Simulation program 'X'?" is complicated by the additional question,
"Which Load Calculation Methodology in TRACE did you select?"

Clark Denson, PE


-----Original Message-----
From: Paul Grahovac [mailto:paul.grahovac at prosoco.com] 
Sent: Wednesday, March 24, 2010 10:36 AM
To: Eurek, John S NWO; Peterson, John (EYP/HP CFS);
bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] differences between energy simulations programs

FYI, another comment on TRANE Trace 700:  the modeling engineers I hired
told me, after consultation with TRANE, that exposed interior concrete
floors, when modeled against the ASHRAE baseline of carpeted floors,
showed a reduction in the cooling load, but an increase in the heating
load.  An increase in the heating load was contrary to my reading in
passive solar books.  I used a simplified simulator for lay people, and
it showed exposed interior concrete floors improved cold-weather
performance over carpeted concrete (HEED, www2.aud.ucla.edu/heed).

I have since heard that TRANE does not model thermal mass well.  I have
also not been able to find anyone with experience modeling the thermal
mass of interior exposed concrete floors using any simulation tool.

Paul Grahovac, LEED AP
PROSOCO, Inc.
785-830-7355

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Eurek, John
S NWO
Sent: Wednesday, March 17, 2010 3:32 PM
To: Peterson, John (EYP/HP CFS); bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Discrepancy between Equest & Trace 6.2

John,

It is like buying a car.  Do you want a truck, manual/automatic,
something
fast.......  You are asking for information overload.  If you know
exactly
what you want it may be easier for us (in this list) to help guide you
to the
best option.

I also was once curious and found the link below.  The end of the paper
has
charts comparing different features.
http://apps1.eere.energy.gov/buildings/tools_directory/pdfs/contrasting_
the_c
apabilities_of_building_energy_performance_simulation_programs_v1.0.pdf 

Another sight.
http://www.wbdg.org/resources/energyanalysis.php


I use Trace 700 (v6.2.4).  Why? Because the first, second and third
company I
worked for used it.  It is good for running loads, but so-so for energy
modeling.  Also I have never used anything else.  I have looked at
equest and
DOE, they both look like learning a completely new programming language.


I wouldn't mind hearing other people's brief views of the programs they
use.
Equest, DOE, HAP, ect.



John Eurek LEED AP
Mechanical Engineer, 
US Army Corps of Engineers
Omaha District CENWO-ED-DA
1616 Capitol Avenue
Omaha, NE 68102
Phone: (402) 995-2134
email: john.s.eurek at usace.army.mil


-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Peterson,
John
(EYP/HP CFS)
Sent: Wednesday, March 17, 2010 2:03 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Discrepancy between Equest & Trace 6.2

 

Has there been any information released on the differences between
energy
simulation programs?  We have a bid requirement with a certain
percentage
listed and we have been asked to address the differences between the bid
model and the newly proposed model.  

 

Thanks in advance -

John

 

John Peterson, PE, LEED AP

HP Critical Facilities Services delivered by EYP

6600 Rockledge Drive, 4th Floor

Bethesda, MD  20817

cell: 202-731-5835 

 

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