90.1 2010 - ERV - Fan Power Limitation Pressure Drop Adjustment

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Hello,

With 90.1 2010, I wonder how to apply the fan power limitation pressure drop adjustment formula for an ERV:

(2.2 * Energy Recovery Effectiveness) - 0.5 in w.c. for each airstream

I don't find example in the 90.1 user's manual about ERV, does the "for each stream" statement apply to the "0.5 in w.c." or to the all formula ?

With a 10,000 cfm ventilation fan and a sensible wheel with a 60% efficiency, what would be the pressure drop adjustment for the ERV?

? 10,000 * ( (2.2 * 0.6 ) - 0.5 * 2) = 3,200 hp

Or

? 10,000 * 2 * ( (2.2 * 0.6 ) - 0.5)=16,400 hp

It's definitively not the same !
Thanks

Julien

Julien Dutel, ing., CEM, CMVP.
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Julien.Dutel at mern.gouv.qc.ca's picture
Joined: 2015-06-05
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Hello Julien,
The entire formula is applied to each air stream, on the system, with an energy recovery device other than Runaround Coil.

When calculating A for each device, the flow CFMD, is the flow through the device, not the total system flow. For example, the flow through an enthalpy wheel might be the only the outdoor air portion of the total system flow.

It?s a good question though. I can see how the wording might trip you up.

[cid:image003.png at 01D09C46.E75BA0D0]
Christopher Jones, P.Eng.
Senior Engineer

WSP Canada Inc.
2300 Yonge Street, Suite 2300
Toronto, ON M4P 1E4
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Jones, Christopher's picture
Joined: 2015-06-11
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?Fan power adjustment is always on the total CFM and by evaluating
following options in similar line of thought, I feel option:1 is the right
approach because in the option:1 the total CFM remains 10,000 whereas it
doubles ~20,000 ?in option:2.

I hope other experts could chime in and share their experience.

Thank you,

2015-08-26 19:01 GMT+05:30 :

--

Javed Iqbal, LEED AP, CEA
Sr. Energy Analyst

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Here is a quick schematic of my project

[cid:image002.jpg at 01D0DFEE.DBFBB0E0]

During design condition (heating and cooling) economiser is off, wheel is on, and OA is at minimum (20% of the supply air). 10,000 cfm ? 20% goes on each stream of the erv.

So based on your last answer the adjustment would be:

? Adjustement for supply air = 10,000 ? 20% ? ( (2.2 ? 0.6 ) - 0.5 ) = 1 640 hp

? Adjustement for return air = 10,000 ? 20% ? ( (2.2 ? 0.6 ) - 0.5 ) = 1 640 hp

Adjustments for the ERV would be : 1640 +1640 = 3280 hp

Am I correct ?

Thanks
Julien

Julien Dutel, ing., CEM, CMVP.
T?l?phone : 418 627-6379, poste 8060

De : Jones, Christopher [mailto:Christopher.r.Jones at wspgroup.com]
Envoy? : 26 ao?t 2015 09:48
? : Dutel, Julien (BEIE); bldg-sim at lists.onebuilding.org
Objet : RE: [Bldg-sim] 90.1 2010 - ERV - Fan Power Limitation Pressure Drop Adjustment

Hello Julien,
The entire formula is applied to each air stream, on the system, with an energy recovery device other than Runaround Coil.

When calculating A for each device, the flow CFMD, is the flow through the device, not the total system flow. For example, the flow through an enthalpy wheel might be the only the outdoor air portion of the total system flow.

It?s a good question though. I can see how the wording might trip you up.

[cid:image001.png at 01D0DFE7.76898DB0]
Christopher Jones, P.Eng.
Senior Engineer

WSP Canada Inc.
2300 Yonge Street, Suite 2300
Toronto, ON M4P 1E4
T +1 416-644-4226
F +1 416-487-9766
C +1 416-697-0065

www.wspgroup.com

Julien.Dutel at mern.gouv.qc.ca's picture
Joined: 2015-06-05
Reputation: 0

It is worth noting that you only get to apply the baseline pressure drop adjustment for an ERV if the baseline is required to have an ERV.

Cory Duggin, PE, LEED AP BD+C
Associate/Energy Modeling Wizard, j.g.
[cid:image001.jpg at 01D0DFE8.D0B20A00]
TLC Engineering for Architecture
direct:

615-346-1939

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Julien,

You need to look at the rest of Table 6.5.3.1.1.A to do the calculation.
A = sum of (PD x CFMD/4131)
You do the calculation for each applicable device listed in Table 6.5.3.1.1.B. (As Cory mentioned, you only include the ERV adjustment if the baseline is required to have an ERV.)
For your ERV only, you have ((2.2 x 0.6) ? 0.5) x (10,000 x 0.2)/4131 = 0.397 for each airstream, or 0.794 total.
With no other pressure drop adjustments, A = 0.794.
You then calculate total baseline fan power individually for each system, = CFMS x 0.00094 + A (for constant volume), using the baseline system supply CFM.
If, for example, the baseline system with energy recovery has 12,000 cfm supply airflow rate, bhp = (12,000 x 0.00094) + 0.794 = 12.074 bhp.
Then Pfan = bhp x 746 / Fan Motor Efficiency, using Table 10.8 for motor efficiency.
You have to split the value for Pfan between the supply, return, exhaust and relief fans in the baseline in the same proportion as the proposed design.

Hopefully I did that right and didn?t forget anything too important.

Best regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

[cid:image002.jpg at 01D0DFF4.BF17D9D0] [cid:image003.jpg at 01D0DFF4.BF17D9D0]

134 South Fitzhugh Street Rochester, NY 14608

T: (585) 698-1956 F: (585) 325-6005

bbishop at pathfinder-ea.com www.pathfinder-ea.com

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Here is my understanding of your answer:

? Yes if the project needs to comply with ECB method or Annex G

? No if the project needs to comply with the prescriptive path 6.5 : I can use the ERV adjustement even if ERV is not required by article 6.5.6.1.

Julien Dutel, ing., CEM, CMVP.
T?l?phone : 418 627-6379, poste 8060

De : Duggin, Cory [mailto:Cory.Duggin at tlc-eng.com]
Envoy? : 26 ao?t 2015 11:20
? : Dutel, Julien (BEIE); Christopher.r.Jones at wspgroup.com
Cc : bldg-sim at lists.onebuilding.org
Objet : RE: [Bldg-sim] 90.1 2010 - ERV - Fan Power Limitation Pressure Drop Adjustment

It is worth noting that you only get to apply the baseline pressure drop adjustment for an ERV if the baseline is required to have an ERV.

Cory Duggin, PE, LEED AP BD+C
Associate/Energy Modeling Wizard, j.g.
[cid:image001.jpg at 01D0DFF3.49B7E5A0]
TLC Engineering for Architecture
direct:

615-346-1939

Julien.Dutel at mern.gouv.qc.ca's picture
Joined: 2015-06-05
Reputation: 0

Bill,

Wow: my 3280 hp wouldn?t make sense at all?: I was mixed up between the SI and IP version and I forgot to divide by 4131 to find bhp.

So yes, you?re right: regarding only the ERV, adjustment would be 0,794 bhp, which need to be add to the rest of the VAV formula or the CV formula.

Thanks for you clear answer.

Julien Dutel, ing., CEM, CMVP.
T?l?phone : 418 627-6379, poste 8060

De : Bishop, Bill [mailto:bbishop at pathfinder-ea.com]
Envoy? : 26 ao?t 2015 11:46
? : Dutel, Julien (BEIE); Christopher.r.Jones at wspgroup.com; Duggin, Cory
Cc : bldg-sim at lists.onebuilding.org
Objet : RE: [Bldg-sim] 90.1 2010 - ERV - Fan Power Limitation Pressure Drop Adjustment

Julien,

You need to look at the rest of Table 6.5.3.1.1.A to do the calculation.
A = sum of (PD x CFMD/4131)
You do the calculation for each applicable device listed in Table 6.5.3.1.1.B. (As Cory mentioned, you only include the ERV adjustment if the baseline is required to have an ERV.)
For your ERV only, you have ((2.2 x 0.6) ? 0.5) x (10,000 x 0.2)/4131 = 0.397 for each airstream, or 0.794 total.
With no other pressure drop adjustments, A = 0.794.
You then calculate total baseline fan power individually for each system, = CFMS x 0.00094 + A (for constant volume), using the baseline system supply CFM.
If, for example, the baseline system with energy recovery has 12,000 cfm supply airflow rate, bhp = (12,000 x 0.00094) + 0.794 = 12.074 bhp.
Then Pfan = bhp x 746 / Fan Motor Efficiency, using Table 10.8 for motor efficiency.
You have to split the value for Pfan between the supply, return, exhaust and relief fans in the baseline in the same proportion as the proposed design.

Hopefully I did that right and didn?t forget anything too important.

Best regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP | Pathfinder Engineers & Architects LLP
Senior Energy Engineer

[cid:image001.jpg at 01D0DFF6.0735F570] [cid:image002.jpg at 01D0DFF6.0735F570]

134 South Fitzhugh Street Rochester, NY 14608

T: (585) 698-1956 F: (585) 325-6005

bbishop at pathfinder-ea.com www.pathfinder-ea.com

[cid:image003.png at 01D0DFF6.0735F570]Carbon Fee and Dividend - simple, effective, and market-based.

Julien.Dutel at mern.gouv.qc.ca's picture
Joined: 2015-06-05
Reputation: 0

If your App G. baseline or Ch 11 Budget Building is required to have an ERV per section 6.5.6.1, then you can apply the pressure drop adjust to your baseline fan power. If you have an ERV in your design, but it is not required by section 6.5.6.1, then you don?t get to apply the ERV PD to the baseline. The idea here is the design decision was made that the heating and cooling savings from the ERV outweigh the increase in fan energy, so you don?t get to increase the baseline power because of a design decision that will benefit the proposed.

I would defer to Bill?s message on the details on the calculation as I didn?t go over it thoroughly.

Cory Duggin, PE, LEED AP BD+C
Associate/Energy Modeling Wizard, j.g.
[cid:image001.jpg at 01D0DFF0.29AA8310]
TLC Engineering for Architecture
direct:

615-346-1939

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Great summary Bill.

Note that if the baseline system includes parallel fan powered boxes, the boxes are to have the default power of 0.35W/cfm.

For those who use eQuest to generate the 90.1-2007 baseline model, only a supply fan is created for each system. You have to add in any return/relief fans and zone exhaust fans as appropriate, splitting the power proportionally to match the proposed case model.

[cid:image003.png at 01D09C46.E75BA0D0]
Christopher Jones, P.Eng.
Senior Engineer

WSP Canada Inc.
2300 Yonge Street, Suite 2300
Toronto, ON M4P 1E4
T +1 416-644-4226
F +1 416-487-9766
C +1 416-697-0065

www.wspgroup.com

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Joined: 2015-06-11
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