[Equest-users] Modeling ISMRE

Fri Apr 5 09:58:28 PDT 2019

Fascinating! (I've got deadlines today so naturally something catches my eye in the mailing list...)

On first pass through that article, it seems to me that the ASHRAE 90.1 committee dropped the ball with respect to considering performance rating energy simulation inputs.

There appears to be no immediately clear path for an energy simulator to get from a prescribed minimum ISMRE / ISCOP to a steady state EER or COP inputs you could apply to typical/library performance curves.

It might be possible to iteratively worsen the inputs of a standard DX unit accomplishing dehumidification and hot gas reheat to generate 70F air, then calculate its resulting "virtual lab" ISMRE / ISCOP rating using custom hourly reports for capacity/input at the stated testing conditions from the  new standard 920 (tables in the linked paper summarize)... tweaking the weather/loading profiles may be necessary to replicate each testing condition - not a small venture.  You could alternatively assemble all of the associated library curves and make a virtual benchmarking spreadsheet to model in parallel what doe2 would output for power in and capacity given [evaporator DB, evaporator WB, condenser DB, PLR], which would make it easier to punch in the various PLR and temperature conditions as variables.  You could then run a solver function on the steady state EIR you'll enter for the unit to arrive at the exact/target prescribed rating. You could then post here and potentially sell copies of your work for 5 bucks a pop until 90.1 catches up...  I'd pay that readily if a conundrum like this were in front of me today.

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Seems to me the ASHRAE Standard 90.1 committee has a little more homework to address this topic fully.  I suggest either:

  1.  Come up with some concurrent steady-state performance criteria and a set of performance curves to fully describe the systems corresponding to the listed ISMRE / ISCOP ratings (rather than dump this legwork on all of the end-users, the majority of which will struggle and probably get the math wrong), or
  2.  Come up with a broad-stroke "derate" of the listed baseline efficiency for a normal DX system performing DOAS duties to fairly account for extra energies resulting from subcooling/hot gas reheat

Then again maybe I'm missing something... does this proposal make sense to anyone?

OK I better get back to work!

~Nick

[cid:image001.png at 01D4EB97.3D7B0B10]
Nick Caton, P.E., BEMP
  Senior Energy Engineer
  Regional Energy Engineering Manager
  Energy and Sustainability Services
  Energy Performance Contracting

D
M
F
E

913 . 564 . 6361
785 . 410 . 3317
913 . 564 . 6380
nicholas.caton at se.com<mailto:nicholas.caton at se.com>

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

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From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Lee Shaver via Equest-users
Sent: Friday, April 05, 2019 9:08 AM
To: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Modeling ISMRE

[External email: Use caution with links and attachments]

________________________________

Hi all,

ASHRAE 90.1-2013 addendum cd adds tables 6.8.1-14 and -15 which include an ISMRE requirement for "electrically operated DX-DOAS units, single package and remote condenser."

ISMRE stands for "Integrated Seasonal Moisture Removal Efficiency" and is measured in pounds of water removed per kWh of electrical energy consumed (lb/kWh).

TRANE has a great article<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.trane.com%2Fcontent%2Fdam%2FTrane%2FCommercial%2Fglobal%2Fproducts-systems%2Feducation-training%2Fengineers-newsletters%2Fstandards-codes%2FADM-APN060-EN_110116.pdf&data=02%7C01%7CNicholas.Caton%40se.com%7Cb5c3aa2118f64e4f25fc08d6b9d0267e%7C6e51e1adc54b4b39b5980ffe9ae68fef%7C0%7C0%7C636900700993138894&sdata=hT9LSLOD1J9MJEZ%2F6wzWJ7tBS1Vzz4%2FdelUH9pTqhrE%3D&reserved=0> on ISMRE and why it's now included in ASHRAE 90.1.

Currently, I'm working on a model with a parametric run for a DOAS unit with an ISMRE that is better than baseline, and an EER that is worse than the baseline.

How can I accurately model this improvement in ISMRE, and the resulting reduction in energy usage for the DOAS units?

Googling "eQuest ISMRE" returns only four hits<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.google.com%2Fsearch%3Fq%3D%2522eQuest%2522%2B%2522ISMRE%2522&data=02%7C01%7CNicholas.Caton%40se.com%7Cb5c3aa2118f64e4f25fc08d6b9d0267e%7C6e51e1adc54b4b39b5980ffe9ae68fef%7C0%7C0%7C636900700993148902&sdata=hDJI4CoBE7wKIHzf2Y%2BvIVUjkVmwdyO22Dc8vkYuc%2FI%3D&reserved=0>, none of which are relevant.
Thanks,

Lee Shaver, Project Manager
Slipstream
608.210.7145 slipstreaminc.org<https://eur02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fslipstreaminc.org%2F&data=02%7C01%7CNicholas.Caton%40se.com%7Cb5c3aa2118f64e4f25fc08d6b9d0267e%7C6e51e1adc54b4b39b5980ffe9ae68fef%7C0%7C0%7C636900700993148902&sdata=4%2B77LWmQyhiXmZPuASZ23n8oT1CXvmE4v5bE1d32F4g%3D&reserved=0>

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