[Equest-users] [External] Re: % LOAD ATTRIBUTED TO OA DELIVERY
Porter, Frederick NOR
fporter at noresco.com
Fri Oct 16 09:09:25 PDT 2015
I second all that from Dan.
My opinion is that the .sim files are wholly inadequate for a proper model review though LEED has allowed it for years. For instance, one can’t tell if a “MIN-AIR-SCH” is even applied to a system from the SV-A report. I don’t think one can even tell what the OA control (economizer or not, type, setpoints...) is.
Why do you need to know the “OA load” then? Do savings from some measure (let me guess, "DCV"), or cooling and heating loads, seem excessive? Does your review require that you calculate it? In any case, Dan has pretty well nailed down what you need to do. Knock the ball back in their court and go find the nearest Oktoberfest. It is Friday again, somehow!
Fred Porter, BEMP, LEED© AP
Principal Engineer
Sustainability Services
NORESCO
2540 Frontier Ave, Suite 100, Boulder, CO 80301
-----Original Message-----
From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Daniel Knapp
Sent: Friday, October 16, 2015 9:57 AM
To: Mark Hallman
Cc: equest-users at lists.onebuilding.org
Subject: [External] Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
Hi Mark,
I don’t think there is a good way to to what you want. As Joe Huang and others have pointed out, the method that you describe is not a reliable or accurate way to separate out the outdoor air load from the other loads. If you’re reviewing the model as a third party and you don’t trust the results, then I would recommend that you ask for clarification on whatever issues/discrepancies you are concerned about. I would also note that we require that modelling files be provided for third party reviews that we carry out. If you don’t have the luxury of getting either the modelling files or further feedback from the modeller, I suggest you simply call out the problems that you see in the results in your report and specify the steps that would need to be taken to alleviate your concerns.
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 Oct 16, 2015, at 11:27 AM, Mark Hallman <Mark.Hallman at rwdi.com> wrote:
>
> Thanks for all the helpful comments, folks.
>
> Is there anyway of parsing this out without having the model available, just the SIM files? I’m reviewing results as a 3rd party but don’t have access to the model nor the hourly results. What I’ve been doing so far is:
>
> Cooling Load without OA = LS-C cooling load Cooling Load with OA =
> Plant Cooling Load (SS-D report) + System Cooling Load (Max Cooling
> elec load from SS-H report)
>
> Tx!
> Mark.
>
> mark hallman
> p.eng. leed ap bd&c
> project engineer
>
> mdh at rwdi.com
> 519 823 1311 x2494
> RWDI: the science of buildings, structures & the environment. See what we do HERE.
>
> From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org]
> On Behalf Of Shaun Martin
> Sent: Thursday, October 15, 2015 13:11
> To: 'Keith Swartz'; 'Porter, Frederick NOR'; 'Nathan Miller'; 'Daniel
> Knapp'; equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
>
> With MIN-AIR-SCH, you have to zero out all zone exhausts, because exhaust overrides the schedule. And, almost every building I work on has ventilation heat recovery, which affects the mixed air temp. I’m not quite sure what will happen at MIN-AIR-SCH =.001. Be careful with the control strategy.
>
> Shaun Martin LEED-AP, BEMP
> Principal
> Shaun Martin Consulting
> #90 – 425 Carrall Street
> Vancouver, BC V6B 6E3
> p. 604-789-1095
>
>
> From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org]
> On Behalf Of Keith Swartz
> Sent: Thursday, October 15, 2015 6:51 AM
> To: Porter, Frederick NOR <fporter at noresco.com>; Nathan Miller
> <nathanm at rushingco.com>; Daniel Knapp <danielk at arborus.ca>
> Cc: equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
>
> Here are details from the help screen:
>
>
> <image001.png>
>
> Keith Swartz, PE | Senior Energy Engineer Seventhwave |
> Madison.Chicago.Minneapolis
> 608.210.7123 seventhwave.org
>
> -----Original Message-----
> From: Porter, Frederick NOR [mailto:fporter at noresco.com]
> Sent: Wednesday, October 14, 2015 11:46 AM
> To: Nathan Miller <nathanm at rushingco.com>; Daniel Knapp
> <danielk at arborus.ca>
> Cc: equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
>
> All,
> Bill describes how to do this easily in his initial reply. The MIN-AIR-SCH at the system level over-rides the zone OA inputs (Actually, I'm not positive what happens if there are zone exhaust fans in the model! I avoid these like the plague.) MOST AHU models should have a SYSTEM MIN-AIR-SCH which is either -999 (default, model uses sum of zone OA flows, or system MIN-OA if there are no zone OA flows) during occupied periods or 0.0 (no econ, no damper leakage) or 0.01-0.03 or so (leakage, economizer allowed) for hours when the system can cycle on during unoccupied periods. Changing this one system schedule to one with zero or 0.01 at all hours is absolutely the easiest way to do a run with "no" OA. It is very easy to do as a "parametric."
>
> Fred
>
> -----Original Message-----
> From: Nathan Miller [mailto:nathanm at rushingco.com]
> Sent: Wednesday, October 14, 2015 7:35 AM
> To: Daniel Knapp; Porter, Frederick NOR
> Cc: equest-users at lists.onebuilding.org
> Subject: [External] RE: [Equest-users] % LOAD ATTRIBUTED TO OA
> DELIVERY
>
> Depending on your system, you can allow economizer by assigning an arbirtrary, tiny OA CFM (like 0.01 CFM) to the zone. Then there is essentially no OA being delivered in normal operation, but economizer can be engaged.
>
>
> Nathan Miller, PE, LEED AP BD+C - Mechanical Engineer/Senior Energy
> Analyst RUSHING | D 206-788-4577 | O 206-285-7100 www.rushingco.com
>
> -----Original Message-----
> From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org]
> On Behalf Of Daniel Knapp
> Sent: Wednesday, October 14, 2015 9:32 AM
> To: Porter, Frederick NOR <fporter at noresco.com>
> Cc: equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
>
> There should be a way to run without outdoor air while still allowing economizer operation. If you set the outdoor air to zero at the zone level, and allow for an economizer at the system level, I imagine that eQUEST would do this. It would be worth looking at the hourly reports for the OA fraction at the system level to confirm that the outdoor air flow rate is behaving as expected.
>
> All the best,
>
> Dan
>
>
> -
> Daniel Knapp, PhD, PPhys, 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 Oct 13, 2015, at 7:37 PM, Porter, Frederick NOR <fporter at noresco.com> wrote:
> >
> > Mark,
> > I'd stick with Bill's original suggestion. Run the model with "zero" OA and compare to the "proposed" case. Seem's close enough to me... As Joe notes, in the end there can be some ambiguity about exactly how the total hourly coil load should be apportioned. If you are curious about how the model works on an hourly basis, generate some hourly AHU reports (coil loads, MA and SA conditions), from the two runs. Do not just compare L- and S- loads reports. L- reports are at a constant temp, and in addition to OA, do not include any "false" loads from overcool/reheat, fan heat... I'm sure there are more.
> >
> > One thing to check first; make sure your coil capacity with the OA is large enough to fully condition the air at each timestep. Also, for models that use it, set the "cooling coil/cool control range" to 0.1F or so to avoid possible small changes in the coil leaving air temps between runs.
> >
> > I think Trace and HAP provide a "ventilation load" in reports they probably do some intermediate calculation each hour for the AHU w/ and w/o OA. They may even allocate it per zone.
> >
> > Food for thought: In buildings without high exhaust flows, some of the "OA ventilation load," imposed by OA at the AHU, actually offsets some infiltration load that would occur throughout the building if that OA was not brought in, or ended up in an ERV somehow. "Simple" simulation programs attempt to account for this with schedules that are applied to infiltration based on initial AHU operating schedules, however those infiltration schedules are not directly linked to OA schedules. I've seen "efficient" buildings that were not adequately pressurized because the nifty heat recovery ventilator exhaust fan used up all the air that would otherwise kept the building pressurized.
> >
> > Fred
> > Fred Porter, BEMP, LEED(c) AP
> > Principal Engineer
> > Sustainability Services
> > NORESCO
> > 2540 Frontier Ave, Suite 100, Boulder, CO 80301 Phone 303.459.7425
> > | Cell 303.748.4536 | fporter at noresco.com www.noresco.com
> >
> > Confidentiality Note:
> > Dissemination, distribution or copying of this e-mail or the information herein by anyone other than the intended recipient, or an employee or agent of a system responsible for delivering the message to the intended recipient, is prohibited. If you are not the intended recipient, please inform the sender and delete all copies.
> >
> >
> >
> >
> > From: Equest-users
> > [mailto:equest-users-bounces at lists.onebuilding.org]
> > On Behalf Of Joe Huang
> > Sent: Tuesday, October 13, 2015 1:58 PM
> > To: equest-users at lists.onebuilding.org
> > Subject: [External] Re: [Equest-users] % LOAD ATTRIBUTED TO OA
> > DELIVERY
> >
> > There are so many differences between what's reported in the LS-D and SS-D that I would not use this method for anything more than an extremely crude look at the load attributable to OA. In Loads, all the heat flows are calculated at the reference temperature (TLOADS) and counted as Cooling if the net space load that hour is positive or Heating if it's negative. In Systems, these loads are corrected to the actual zone temperature and the load from OA and interzone heat transfer added, while solving for the zone temperature. If the zone temperature is outside the thermostat deadband, a deficit would be considered a heating load and an excess as a cooling load on the HVAC system.
> >
> > There's a much better way to get the OA load, but it would take some work, either with a User-Function, which unfortunately is not available in DOE-2.2 (although I've heard that Expressions could do much the same thing...), or by post-processing hourly outputs. Print out an Hourly Report with the following parameters: Outdoor Air Temp (To), Room Air Temperature (Trm), Outside Air CFM, and the Zone Load. Then, use Excel or awk ( my favorite :-) :-) ) to calculate the load due to the OA as (Trm-To)*CFM*Cp of air . This can then be compared to the Zone Load, but you'll notice some anomalies such as during the swing season when the OA Load is actually "free cooling". You'll then have to decide how to attribute the OA heat flows to the HVAC loads, which can be tricky.
> >
> > Various people, including me, Dan Fisher, Jason Glazer, etc., have
> > wandered into this area of deriving component loads, and have found
> > that it ultimately raises philosophical questions. :-) :-)
> >
> > 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 10/13/2015 9:02 AM, Keith Swartz wrote:
> > Good point, David. The system report adds more than just ventilation load to the space load.
> >
> > Keith Swartz, PE | Senior Energy Engineer Seventhwave |
> > Madison.Chicago.Minneapolis
> > 608.210.7123 seventhwave.org
> >
> > From: David Eldridge [mailto:DEldridge at grummanbutkus.com]
> > Sent: Tuesday, October 13, 2015 10:47 AM
> > To: Keith Swartz <KSwartz at seventhwave.org>; Mark.Hallman at rwdi.com
> > Subject: RE: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > I'm not sure if that will exactly give the ventilation loads - the "L" reports are the building space loads, but the "S" reports will include other system effects such as fan heat, reheat, heat gain to the return air, so that the difference might not exactly be a ventilation load, and might be pretty far from an OA-only load.
> >
> > If there is a preheat coil, you can set up a report to trend that coil's load if you are after the heating loads. You could trend the cooling coil load as well, but this is a function of economizer operation and outside air temperature as well.
> >
> > David
> >
> >
> >
> >
> > David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP
> > Grumman/Butkus Associates
> >
> >
> >
> > From: Equest-users
> > [mailto:equest-users-bounces at lists.onebuilding.org]
> > On Behalf Of Keith Swartz
> > Sent: Monday, October 12, 2015 8:55 AM
> > To: equest-users at lists.onebuilding.org
> > Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > Mark,
> >
> > Look at the differences between values in reports LS-D and SS-D.
> > SS-D includes ventilation. LS-D does not. (The first letter "S"
> > stands for "system." "L" is for "load," the load in the space.)
> >
> > Keith Swartz, PE | Senior Energy Engineer Seventhwave |
> > Madison.Chicago.Minneapolis
> > 608.210.7123 seventhwave.org
> >
> > From: Shaun Martin [mailto:smartin at shaunmartinconsulting.com]
> > Sent: Friday, October 09, 2015 12:13 PM
> > To: 'Mark Hallman' <Mark.Hallman at rwdi.com>; 'Bishop, Bill'
> > <bbishop at pathfinder-ea.com>; equest-users at lists.onebuilding.org
> > Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > Hi Mark,
> >
> > You can use hourly reports to pull out the outside air volume (variable PO) plus the supply and return volumes and temperatures. Then off to a spreadsheet.
> >
> > Or, if you're feeling ambitious, you could write an input function (see Topics).
> >
> > Shaun
> >
> > Shaun Martin LEED-AP, BEMP
> > Principal
> > Shaun Martin Consulting
> > #90 - 425 Carrall Street
> > Vancouver, BC V6B 6E3
> > p. 604-789-1095
> >
> >
> >
> >
> > From: Equest-users
> > [mailto:equest-users-bounces at lists.onebuilding.org]
> > On Behalf Of Mark Hallman
> > Sent: Wednesday, October 7, 2015 7:59 PM
> > To: 'Bishop, Bill' <bbishop at pathfinder-ea.com>;
> > 'equest-users at lists.onebuilding.org'
> > <equest-users at lists.onebuilding.org>
> > Subject: Re: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > Thanks Bill, nice tip. Any way of parsing it out without running two simulations?
> >
> > Tx!
> > Mark.
> >
> > mark hallman
> > p.eng. leed ap bd&c
> > project engineer
> >
> > mdh at rwdi.com
> > 519 823 1311 x2494
> > RWDI: the science of buildings, structures & the environment. See what we do HERE.
> >
> > From: Bishop, Bill [mailto:bbishop at pathfinder-ea.com]
> > Sent: Wednesday, October 07, 2015 11:12
> > To: Mark Hallman; 'equest-users at lists.onebuilding.org'
> > Subject: RE: % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > One way would be to create a MIN-AIR-SCH with all hourly values set to 0 (or 0.001 to activate economizer), apply it to all SYSTEMs and use the difference in the outputs.
> >
> > Regards,
> > ~Bill
> >
> > William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers
> > & Architects LLP Senior Energy Engineer <image001.jpg>
> > <image002.jpg>
> >
> > 134 South Fitzhugh Street Rochester, NY 14608
> > T: (585) 698-1956 F: (585) 325-6005
> > bbishop at pathfinder-ea.com www.pathfinder-ea.com
> > <image003.png>Carbon Fee and Dividend - simple, effective, and market-based.
> >
> >
> > From: Equest-users
> > [mailto:equest-users-bounces at lists.onebuilding.org]
> > On Behalf Of Mark Hallman
> > Sent: Wednesday, October 07, 2015 10:59 AM
> > To: 'equest-users at lists.onebuilding.org'
> > <equest-users at lists.onebuilding.org>
> > Subject: [Equest-users] % LOAD ATTRIBUTED TO OA DELIVERY
> >
> > Hi there,
> >
> > Is there a way to accurately parse out from the eQUEST output file the percentage of the cooling and heating load that is attributed to OA delivery? Any advice would be appreciated.
> >
> > Thanks in advance!
> > Mark Hallman.
> >
> >
> >
> >
> > mark hallman
> > p.eng. leed ap bd&c
> > project engineer
> >
> > mdh at rwdi.com
> > 519 823 1311 x2494
> > RWDI: the science of buildings, structures & the environment. See what we do HERE.
> >
> >
> >
> >
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