[Equest-users] Boiler HIR and Section G3.1.1

Nick Caton ncaton at smithboucher.com
Tue Jul 2 08:46:54 PDT 2013


Regarding boiler HIR input vs. efficiency... Your reviewer's commentary isn't clear by your description, but you might find the attached recent discussion informative regarding thermal vs. combustion efficiencies.

The issue of whether it's appropriate to model boiler thermal efficiency (inclusive of flue/jacket losses), and if so exactly how, is to my best understanding a bit of a toss-up right now for 90.1/LEED.  The attached discussion thread takes the issue to the sidewalk's end however, so I hope you can use this to figure out where your reviewer is coming from and how to respond in turn.

~Nick

[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of r s
Sent: Tuesday, July 02, 2013 10:27 AM
To: vamshi ranga
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Boiler HIR and Section G3.1.1

Hi Vamshi,
Just wondering, you say two buildings? Was there any MPR issue raised within PIf1 in the review about having only one building per LEED submittal?

Ramya

On Tue, Jul 2, 2013 at 11:04 AM, vamshi ranga <vamshiranga at gmail.com<mailto:vamshiranga at gmail.com>> wrote:
Dear All,

I have following doubts, I would be very grateful for your valuable time,

1. We have modeled a boiler with 82% combustion efficiency in eQUEST with HIR = 1.219  which is just the inverse of boiler efficiency . But from LEED reviewer, we got comment saying that, HIR of 1.219 is equivalent to 77% efficiency. Could you please let us know, how to convert combustion efficiency to HIR

2. We have two buildings, one is Main Office building (7 day week, 8hr running and Air-Conditioned, Main Office building has 5 to 7% of total two building areas) and the other is Factory+Office building (7 day week, Factory is 24 hr running and Air-Conditioned with 100% of occupancy, lighting and equipment on all the time. While the Factory's Office is 24hr running and Air-Conditioned with 50% of occupancy, lighting and equipment on all the time) which are connected by enclosed bridge (air conditioned). These buildings are modeled together in eQUEST and it comes to be System 7 (Boiler for heating) as per Table G 3.1.1. After reading it for many number of times and to confirm my understanding of the section, doubts are as follows on ASHRAE Appendix G Section G3.1.1

                - What should be the system type for Main Office building (Conditioned area is around 45000 Sq ft)? and let me know the exception of G3.1.1 if any gets applied
                - What should be the system type for factory's Ground Floor Office building? (Area is around 150000 Sq ft) and Does the exception "Schedules that differ by 40 equivalent full load hours" gets applied? since the diversity is 50% for factory's office, if this exception is not applicable, let me know how the equivalent full load hours need to be calculated )
                - What should be the system type for Factory's First Floor office building? (This floor is total office, and ground floor factory area is of double height from ground)
                - Does the exceptions of Section G 3.1.1 applies at building level or at each system level? Exception "b" says both the things, so there is confusion
                - Does the term "Peak thermal loads" in exception "b" consider the load added due to outside air as well?

Let me know, if you need any further clarification to resolve my doubts.

Thanks,
Vamshi.

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