[Trace-users] Part load conditions

[Duncan S. McClellan]

A diligent engineer should know if the calcs are performed correctly by performing back-checks.  You shouldn't depend on a LEED reviewer to determine the accuracy of your methodologies.  The fan power calcs are not always right.   Sometimes they work, sometimes they don't.  If want to be sure, always back-check via hand calcs.  Scott's comment regarding "kW/cfm" is very important.  Don't input anything as "horsepower".  If you enter a 10hp fan, you're going to get a 10kW fan.  It's not a unit display issue, it's actually using 10kW.  Motor efficiency is already included in the Appendix G calc if you are performing it correctly. Here is a message I received from CDS several years ago regarding Horsepower units:

Duncan,

You're right.  3 HP does not equal 3 kW however when you select units of HP in TRACE, the program automatically assumes 75% efficiency and that 75% basically cancels the conversion between HP and kW (0.746).

Eric Sturm
CDS Marketing Engineer
Trane Commercial Systems
Ingersoll Rand
3600 Pammel Creek Rd
La Crosse, WI 54601

Office:  +1.608.787.3926
Fax:  +1.608.787.3005
Email:  cdshelp at trane.com<mailto:cdshelp at trane.com>
Website:  www.tranecds.com<http://www.tranecds.com/>


Duncan McClellan PE, BEMP, LEED AP
Mechanical Engineer

CLARK NEXSEN
Architecture & Engineering
6160 Kempsville Circle Suite 200A
Norfolk, VA 23502
757.455.5800 Office
757.455.5638 Fax
dmcclellan at clarknexsen.com<mailto:dmcclellan at clarknexsen.com>
www.clarknexsen.com<http://www.clarknexsen.com%20>


From: trace-users-bounces at lists.onebuilding.org [mailto:trace-users-bounces at lists.onebuilding.org] On Behalf Of Houcine Tlemsani
Sent: Thursday, January 24, 2013 12:31 PM
To: Caballero, Catalina; Scott Parker; trace-users at lists.onebuilding.org
Cc: Varghese, Saju
Subject: Re: [Trace-users] Part load conditions

To All

We have submitted the trace report fan power calcs to LEED on multiple jobs and we had no problems.
The calcs are accurate.


Houcine Tlemsani

Mechanical Designer

MEP Engineering Solutions

houcine at mepengsolutions.com<mailto:houcine at mepengsolutions.com>

Phone:  850.429.8288

Fax: 850.429.8334

________________________________
From: trace-users-bounces at lists.onebuilding.org<mailto:trace-users-bounces at lists.onebuilding.org> [mailto:trace-users-bounces at lists.onebuilding.org] On Behalf Of Caballero, Catalina
Sent: Thursday, January 24, 2013 8:44 AM
To: 'Scott Parker'; trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Cc: Varghese, Saju
Subject: Re: [Trace-users] Part load conditions

Scott,

What we have seen is that the Trace700 PRM Sizing works correctly  and you just need to submit the PRM report but I don't know if that particular requirement for  G3.1.3.15 Part 2 can be done using it.

Thanks.


Catalina Caballero, AIA. Assoc., LEED GA.
Johnson, Avedano, Lopez, Rodriguez & Walewski
Engineering Group, Inc.

2510 NW 97th Avenue, Suite 220, Miami, Florida 33172
Tel. (305) 594-0660 Ext. 217 Fax (305) 594-0907

Visit us online: www.jalrw.com<http://www.jalrw.com/>

[cid:image001.jpg at 01CDFA35.CAA0F810]

HVAC - Electrical - Plumbing - Fire Protection
Sustainable Development - Commissioning


This email and any files transmitted with it are confidential and are intended solely for the use of the individual or entity to which they are addressed. If you are not the intended recipient or the person responsible for delivering the email to the intended recipient, be advised that you have received this email in error and that any use, dissemination, forwarding, printing, or copying of this email is strictly prohibited.





From: Scott Parker [mailto:sparker at aeieng.com]
Sent: Thursday, January 24, 2013 9:15 AM
To: Caballero, Catalina; trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Subject: RE: Part load conditions

Catalina,

I would guess that you are working on a LEED project.  From my experience the LEED reviewer will not accept the automatic fan calculation within Trace.  You need to manually calculate the maximum break HP for each fan for the baseline systems.  I recommend putting them in units of kW/CFM.  You will need to manually do the fan power calculations according to 90.1 and adjust for any "allowances" per 90.1.  Please don't use the Full Load Energy Rate numbers I have used.  You'll need to calculate these for your specific conditions per 90.1 requirements.
[cid:image002.jpg at 01CDFA35.CAA0F810]
Scott

From: Caballero, Catalina [mailto:ccaballero at jalrw.com]
Sent: Thursday, January 24, 2013 9:03 AM
To: Scott Parker; trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Subject: RE: Part load conditions

Can the software calculate it automatically with the following feature on?

[cid:image003.jpg at 01CDFA35.CAA0F810]

Regards,

Catalina

From: Scott Parker [mailto:sparker at aeieng.com]
Sent: Thursday, January 24, 2013 9:01 AM
To: Caballero, Catalina; trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Subject: RE: Part load conditions

Catalina,

You can define a custom fan curve based on the 90.1 cubic equation, but I would recommend that you use the 90.1 fan curve library member that comes with the program.  The curve is the same for 2004 and 2007 versions of 90.1.

[cid:image007.png at 01CDFA35.CAA0F810][cid:image008.jpg at 01CDFA35.CAA0F810]
Scott

From: trace-users-bounces at lists.onebuilding.org<mailto:trace-users-bounces at lists.onebuilding.org> [mailto:trace-users-bounces at lists.onebuilding.org] On Behalf Of Caballero, Catalina
Sent: Thursday, January 24, 2013 8:53 AM
To: trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Subject: [Trace-users] Part load conditions

Hi all,

How do you show this method on Trace 700 for System 6?

[cid:image009.jpg at 01CDFA35.CAA0F810]


Thanks,


Catalina Caballero, AIA. Assoc., LEED GA.
Johnson, Avedano, Lopez, Rodriguez & Walewski
Engineering Group, Inc.

2510 NW 97th Avenue, Suite 220, Miami, Florida 33172
Tel. (305) 594-0660 Ext. 217 Fax (305) 594-0907

Visit us online: www.jalrw.com<http://www.jalrw.com/>

[cid:image001.jpg at 01CDFA35.CAA0F810]

HVAC - Electrical - Plumbing - Fire Protection
Sustainable Development - Commissioning


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