[Equest-users] [Bldg-sim] Expert advice on Wall Insulation study in eQuest

Tue Apr 28 18:29:17 PDT 2015

HI All,

How we present data is also important. Speaking of the "law of diminishing
returns" in a tropical climate, the scale / granularity of your graph can
make a relatively flat graph  'look' linear. In the case of New Delhi, as
indicated by the graph the the impact of 0.7 U-value versus 0.2 U-value is
about 0.4% difference in energy consumption per unit area. See below.  I
expect this percentage to be higher for temperate climates and dependent on
the amount of exterior surface area (shape of the building) and the kind of
space types within the building.

[image: Inline image 1]
Regards

Ramya Shivkumar

On Tue, Apr 28, 2015 at 3:39 PM, Nicholas Caton <ncaton at catonenergy.com>
wrote:

> Great discussion!
>
>
>
> Since this thread has clearly gathered attentions of the right
> individuals, I’d like to layer on a query which may further inform Mayank’s
> efforts:
>
>
>
> Is the “law of diminishing returns” as you improve envelope insulation
> universal to ALL climates, in practice or in theory?  While I have reliably
> observed such behavior exploring comparable ECM’s in temperate climates, I
> am curious whether tropical or arctic climates should expect (all else
> being equal) a relatively “flatter” curve when plotting R-value against
> annual energy savings?
>
>
>
> My gut tells me the reduced opportunity to leverage airside economizer
> function or operable windows would make incremental insulation increases
> more attractive for annual energy consumption, but experience has taught me
> to question my gut on such matters (…Thanks Joe!).
>
> Regards,
>
>
>
> ~Nick
>
>
>
> *NICK CATON, P.E.*
> *Owner*
>
>
>
> *Caton Energy Consulting*
>   1150 N. 192nd St., #4-202
>
>   Shoreline, WA 98133
>   office:  785.410.3317
>
> www.catonenergy.com
>
>
>
> *From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
> Behalf Of *Joe Huang
> *Sent:* Tuesday, April 28, 2015 11:56 AM
> *To:* Daniel Knapp; Mayank Bhatnagar
> *Cc:* eQUEST Users List
> *Subject:* Re: [Equest-users] [Bldg-sim] Expert advice on Wall Insulation
> study in eQuest
>
>
>
> Dan,
>
> Very good point!   I didn't even think about this, i.e., that the plot was
> against conductance and not resistance.
> Therefore, I would conclude that eQUEST is behaving properly.
>
> Joe
>
> Joe Huang
>
> White Box Technologies, Inc.
>
> 346 Rheem Blvd., Suite 205A
>
> Moraga CA 94556
>
> yjhuang at whiteboxtechnologies.com
>
> http://weather.whiteboxtechnologies.com for simulation-ready weather data
>
> (o) (925)388-0265
>
> (c) (510)928-2683
>
> "building energy simulations at your fingertips"
>
> On 4/27/2015 11:12 AM, Daniel Knapp wrote:
>
> Hi Mayank,
>
>
>
> I think on further reflection you are seeing exactly what you should be
> seeing. The energy consumption should go down linearly with the U-value.
> What does saturate is the energy savings compared to insulation thickness
> or R-value which is plotted as 1/U. Here is a graph of energy vs. U and
> energy vs R for your building:
>
>
>
> All the best,
>
> Dan
>
>
>
>
>
>
>
> —
> Daniel Knapp, PhD, PPhys, LEED® 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 Apr 27, 2015, at 6:15 AM, Mayank Bhatnagar <mayank.23aug at gmail.com>
> wrote:
>
> Thank you Joe and Daniel for your response.
>
> As you suggested, I checked LS-C report for wall conduction variation
> w.r.t. U-value. It is also giving linear trend for wall conduction.
> Additionally, I have done same analysis for without internal loads
> (occupancy, lighting and equipment load) as Joe indicated about the
> compounding effect. I still get linear trend between the energy consumption
> and U-value.
>
> For your reference, I am attaching inp, pd2 and weather file.
>
>
>
> On Thu, Apr 23, 2015 at 8:10 PM, Joe Huang <
> yjhuang at whiteboxtechnologies.com> wrote:
> Mayank, Daniel,
>
> I think it's a good idea to look at the component loads in the LS-C
> reports, but I want to add some words of caution.
> The loads (actually heat flows) shown in those reports are calculated at
> the constant Reference Temperature, and categorized as either heating
> or cooling if the total load of the building that hour is negative or
> positive. These loads are corrected when DOE-2 solves for the actual
> room temperature based on simple UA-deltaT principles.  If you want the
> corrected wall loads, you need to get an hourly report of the wall loads
> and then correct for the temperature difference Troom - Treference.
>
> I'm not sure if this level of detail is warranted, though.  I also suspect
> there's some other compounding effect that's giving you the results that
> you report.
>
> Joe
>
> Joe Huang
> White Box Technologies, Inc.
> 346 Rheem Blvd., Suite 205A
> Moraga CA 94556
> yjhuang at whiteboxtechnologies.com
> http://weather.whiteboxtechnologies.com for simulation-ready weather data
> http://www.whiteboxtechnologies.com
> (o) (925)388-0265
> (c) (510)928-2683
> "building energy simulations at your fingertips"
>
>
> On 4/23/2015 6:18 AM, Daniel Knapp wrote:
> Hi Mayank,
>
> I recommend opening up the SIM file (you can do this by going to Tools ->
> View Simulation Output) and looking at the LS-C and LV-D reports. In the
> LS-C report you can find the contribution to the peak heating and cooling
> loads that come from the walls. From this you should be able to figure out
> how the wall conduction is changing as a fraction of the peak loads as you
> decrease the wall U-value. In the LV-D report (scroll to the very end of
> it) there is a summary of the U-values for each exterior surface. This
> might be a good place to look to make sure that the effective U-values that
> eQUEST is simulating are matching up with your expectations of what the
> U-values should be.
>
> I would agree that the energy savings should saturate at some point.
>
> All the best,
> Dan
>
>
> —
> Daniel Knapp, PhD, PPhys, LEED® 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 Apr 23, 2015, at 5:00 AM, Mayank Bhatnagar <mayank.23aug at gmail.com>
> <mayank.23aug at gmail.com> wrote:
>
> Hi Claire,
>
> Thanks for your response.
>
> The analysis has been done on an 8 hour operating office building in New
> Delhi. The mechanical system is packaged single zone system with electric
> resistance heating.
>
> Please let me know if you need more information.
>
> Thanks
>
> Regards,
> Mayank
>
> On Thu, Apr 23, 2015 at 2:25 PM, Claire Das Bhaumik
> <claire at inklingllp.com> <claire at inklingllp.com> wrote:
> Mayank,
>
> I think we need to know a bit more about the building:
> - Location (some parts of India are cool, others hot!)
> - Building usage - office, domestic, retail? Hours of use?
> - Servicing - heating and cooling? Mechanical or natural vent?
>
> Regards,
>
> Dr Claire Das Bhaumik CEng FCIBSE
>
> Partner - Inkling LLP
>
>
> e: claire at inklingllp.com
>
> t:  07950 282800
>
> w: www.inklingllp.com
>
> Follow us on Twitter: @DasInkling
>
> Partnership No. OC367619
>
>
> On Thu, Apr 23, 2015 at 9:51 AM, Mayank Bhatnagar <mayank.23aug at gmail.com>
> <mayank.23aug at gmail.com> wrote:
> Dear All,
>
> We are working on a national level research project in India. A building
> envelope analysis is a part of this project. By doing analysis, we
> have found a vague results in trend (linearly downward) of reduction in
> energy consumption with reducing wall U-value in eQUEST.
>
> Theoretically, the energy consumption should approach to stagnant with
> reduction in wall U-value.
>
> Please refer figure.
>
> Appreciate if anyone put light on this.
>
> Thank you.
>
> Regards,
>
> Mayank Bhatnagar
>
> Theoretical should come like this.
> <image.png>
>
> In eQuest the trend is-
> <image.png>
>
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> <Small Office Bldg_v5_4.pd2><Small Office
> Bldg_v5_4.inp><IND_New.Delhi.421820_ISHRAE.BIN>
>
>
>
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