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

[Nick Caton]

Hi Daniel!

The wrench in the spokes is that 90.1 prescribes a combustion efficiency (less flue/jacket losses), without providing any further guidance for how to arrive at an overall thermal efficiency for modeling purposes.

It isn't a problem isolated to eQuest/DOE2, but put another way 90.1/LEED only provide part of what we need to define baseline HIR inputs for a comparison to real-world equipment and losses.  A full discussion is within the attached thread if you're interested =).

This of course might have nothing to do with Vamshi's reviewer's commentary - I don't think that issue has been made clear just yet...

~Nick

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 

-----Original Message-----
From: Daniel Knapp [mailto:danielk at arborus.ca] 
Sent: Tuesday, July 02, 2013 11:13 AM
To: Nick Caton
Cc: r s; vamshi ranga; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Boiler HIR and Section G3.1.1

I don't know if this helps, but from the perspective of eQuest/DOE-2, the HIR is the ratio of the fuel heat input to the boiler to the heating capacity at full load.  I.e. all DOE-2 cares about is how much fuel to assign each unit of heat produced for the building.  If you know what the fuel input and the heating capacity at full load are you may be able to bypass the thorny nature of the combustion efficiency vs. thermal efficiency question?

Cheers,
Dan

-
Daniel Knapp, PhD, P Phys, LEED(r) AP O+M
danielk at arborus.ca

Arborus Consulting
Energy Strategies for the Built Environment www.arborus.ca
76 Chamberlain Avenue
Ottawa, ON, K1S 1V9
Phone: (613) 234-7178 ext. 113
Fax: (613) 234-0740




On 2013-07-02, at 11:46 AM, Nick Caton <ncaton at smithboucher.com> wrote:

> 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
>  
> <image001.jpg>
>  
> 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> 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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