[Equest-users] LEED review comments for System 5 heating source

[Paul Riemer]

Lan,
I have always taken G.3.1.3.2 to mean the same FOSSIL fuel as the proposed design to prevent switching between natural gas, fuel oil, coal, and propane.  Reading electric might feel okay until you get to the natural draft clause.

Assuming your Proposed electric heating consumption includes both your misc. heaters and VFR compressors operating in heating mode, I suggest your system is Fossil/Electric Hybrid heat and that you should model system 5 with natural gas boiler(s) and check the 'other' box noting hybrid heat.  If you want to be compared against electric heated (system 6 with fan powered boxes & electric resistance), you need to get the gas in your OA unit set aside like an old CIR did for gas preheat.

The beta LEED interpretations database has elevated some CIRs to be precedent setting for LEED 2009+, maybe that gas preheat one made the list.  Their website has been a bit skittish for me lately, so I suggest you to go USGBC.org, use the sign in link and then go to LEED - Certification Tools - LEED Interpretations.  I say skittish because I get an error if I try navigate to the interpretations page and then log in.

Paul Riemer, PE, LEED AP
DUNHAM

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Carol Gardner
Sent: Thursday, June 30, 2011 10:31 PM
To: Paul Diglio
Cc: equest-users at lists.onebuilding.org; Li, Lan
Subject: Re: [Equest-users] LEED review comments for System 5 heating source

Lan,

Since you said that your rooftop unit which is providing your outside air uses gas, I think you have modeled it correctly. Something you might want to do is look at using a different thermostat schedule for your electric resistance heaters, It sounds like it might be justifiable to set them to meet a lower heating temperature. As long as you keep the schedule for them the same between the baseline and the proposed building you should be okay..

Carol


On Thu, Jun 30, 2011 at 2:48 PM, Paul Diglio <paul.diglio at sbcglobal.net<mailto:paul.diglio at sbcglobal.net>> wrote:
Lan:

90.1-2007 requires a system 5 with a fossil fuel hot water boiler as you have modeled, but in 90.1-2007 Table G3.1 Number 10 HVAC Systems Base Building Performance column it states that you need to meet any system-specific requirements in Section G3.1.3.

In G3.1.3.2, it states that for system 5, the boiler plant shall use the same fuel as the proposed design, which in your case is electric resistance and compressor heat pump energy.  I would model electric hot water boilers.

Paul Diglio

________________________________
From: "Li, Lan" <lli at sbmce.com<mailto:lli at sbmce.com>>
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Sent: Thu, June 30, 2011 4:24:27 PM
Subject: [Equest-users] LEED review comments for System 5 heating source

Dear eQuesters,

I just got LEED review comments for my project. Our proposed design is VRF system with roof top unit providing ventilation air. Roof top unit is using gas as heating source. There are misc. elec. heaters in the building for places like entries. I interpreted my building heating source as "electric hybrid" and used hot water fossil fuel boiler as my base design. The comments I got read as the follows:

Section 1.1.A of the form indicates that the primary heating source is fossil fuel. However, the electric heating energy use reported in Table EAp2-5 for the Proposed Case exceeds the fossil fuel heating energy use. Please verify that the correct heating source has been selected. If electric heating is the primary heating source, please change the Baseline system type accordingly. Provide updated simulation results and a revised Prerequisite Form as necessary.

I couldn't find an official definition either on LEED reference book or 90.1. What is your take on this?

Your input is highly appreciated! Thank you very much!

Lan




Lan Li, PE, LEED AP BD+C
Mechanical Engineer
Scheeser Buckley Mayfield LLC
1540 Corporate Woods Parkway
Uniontown, OH 44685
Phone: (330) 896-4664<tel:%28330%29%20896-4664> ext. 123
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lli at sbmce.com<mailto:lli at sbmce.com>
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--
Carol Gardner PE
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