[Bldg-sim] Bldg-sim Digest, Vol 209, Issue 2
Jason Glazer
jglazer at gard.com
Mon Apr 14 04:28:39 PDT 2025
Holly
Thanks for providing the background on such an interesting
approach. Do you end up with a map of COPs at different
operating conditions in your spreadsheets, especially for 2?
Is that something you could share?
Jason
On 4/11/2025 4:27 PM, Samuelson, Holly via Bldg-sim wrote:
> Hi Jason,
> Regarding modeling the efficiency of equipment...
> It depends on whether you're modeling a specific system
> for a specific building project, or if you're trying to
> model generalized performance, for example for research.
> I'll comment on the latter scenario. For generalized
> research purposes, where we don't know the exact heat pump
> system and configuration, my team has found that energy
> simulation results are too sensitive to many of the heat
> pump details in the energy model. Therefore, to avoid our
> results being overly-specific to one heat pump model and
> configuration we've done one of the following two things.
>
> 1.
> We've output the annual heating and cooling demands
> from tour energy model, then applied the heat pump
> heating or cooling COPs in a spreadsheet. We've
> found the COPs from a published study with realized,
> weather-dependent, COPs (from representative climates
> and buildings)
>
> 2.
> We've also done this with hourly performance, based on
> realized, weather-dependent COPs at different
> temperatures from representative field studies. For
> interpolation, we've calculated the maximum possible
> COP (based on the Carnot Cycle) for each time step,
> then scaled those values down to something more
> realistic, based on the results from the published
> field studies.
>
> Hope this helps.
> Best,
> Holly
>
>
> A black and white letter h Description automatically generated
>
>
>
> *Holly Samuelson*
>
> Associate Professor of Architecture
>
> Harvard University | Graduate School of Design
>
> www.hollysamuelson.com <http://www.hollysamuelson.com/>
>
> /Unless otherwise noted, I do not expect a reply outside
> your normal working hours. /
>
>
>
> ------------------------------------------------------------
> *From:* Bldg-sim <bldg-sim-bounces at lists.onebuilding.org>
> on behalf of bldg-sim-request at lists.onebuilding.org
> <bldg-sim-request at lists.onebuilding.org>
> *Sent:* Thursday, April 10, 2025 4:00 PM
> *To:* bldg-sim at lists.onebuilding.org
> <bldg-sim at lists.onebuilding.org>
> *Subject:* Bldg-sim Digest, Vol 209, Issue 2
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> Today's Topics:
>
> 1. How do you model minimum and high efficiency DX
> cooling and
> heat pump equipment? (Jason Glazer)
> 2. Re: How do you model minimum and high efficiency DX
> cooling
> and heat pump equipment? (chris.malcolm.yates at gmail.com)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 10 Apr 2025 08:28:44 -0500
> From: Jason Glazer <jglazer at gard.com>
> To: bldg-sim at onebuilding.org
> Subject: [Bldg-sim] How do you model minimum and high
> efficiency DX
> cooling and heat pump equipment?
> Message-ID: <bf88e843-c541-47e9-9462-0ff92a23c74a at gard.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> I just posted a question on unmet hours:
>
> https://unmethours.com/question/101487/how-do-you-model-minimum-and-high-efficiency-dx-cooling-and-heat-pump-equipment/
> <https://unmethours.com/question/101487/how-do-you-model-minimum-and-high-efficiency-dx-cooling-and-heat-pump-equipment/>
>
> "I?m trying to get an understanding of the practice of
> modelers when comparing minimum efficiency and
> high-efficiency DX equipment and heat pumps for different
> applications. I know that detailed performance data is
> sometimes difficult to get. How successful have you been in
> trying to get detailed performance data from vendors? If you
> can?t get data like that, how do you model the equipment?
> How do you model the indoor fan? If you know it is
> multispeed, how do you figure out those details? What if all
> you have is the AHRI data (EER/EER2, SEER2/IEER, COP at
> 17/47, capacities, full load/intermediate/minimum airflows)
> what assumptions do you have to make? What performance
> curves do you use? If you can get data from the
> manufacturer, what assumptions do you still need to make? Is
> it different for residential size equipment than commercial?"
>
> If you can respond to this email or post a response on
> unmethours, I would appreciate it.
>
> Thanks
>
> Jsaon
>
>
> --
> Jason Glazer, P.E., BEMP, GARD Analytics, ASHRAE 209 chair
> Admin for onebuilding.org building performance mailing lists
>
>
>
> ------------------------------
>
> Message: 2
> Date: Thu, 10 Apr 2025 15:47:12 +0100
> From: <chris.malcolm.yates at gmail.com>
> To: "'Jason Glazer'" <jglazer at gard.com>,
> <bldg-sim at onebuilding.org>
> Subject: Re: [Bldg-sim] How do you model minimum and high
> efficiency
> DX cooling and heat pump equipment?
> Message-ID: <000801dbaa27$72659cf0$5730d6d0$@gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Hi Jason,
>
> I asked this question over a decade ago to a couple of
> different suppliers in the UK. What intrigued me was the
> very high efficiency that suppliers (e.g., Mitsubishi,
> Daikin) quoted - figures that we just plugged into
> building code calculations. Based on these figures it
> seemed like a no-brainer to just rip out centrifugal
> chillers and replace them with acres of DX systems! My
> enquiries came to little. The only interesting thing that
> I got (from a Danish academic) was that the market was
> very Germany-centric which resulted in SEER & COP being
> established at what seemed like, for the UK at least,
> quite extreme temperature bins.
>
> The impression I got is that, locally, there is some
> design experience within the sales teams but it's limited
> to sizing. The best I got back in terms of energy was
> something along the lines of "we've got some boffins over
> in Japan, we can try asking them."
>
> I don't doubt that they have some very clever people. Are
> they clever enough to get centrifugal-like performance out
> of a scroll compressor? I don't know. Reading your
> message, it's interesting to see that maybe the US market
> is subject to the same "black box" issues!
>
> Good luck. I'll keep an eye on this thread and Unmet hours.
>
> Cheers
>
> Chris
>
> -----Original Message-----
> From: Bldg-sim <bldg-sim-bounces at lists.onebuilding.org> On
> Behalf Of Jason Glazer via Bldg-sim
> Sent: 10 April 2025 14:29
> To: bldg-sim at onebuilding.org
> Subject: [Bldg-sim] How do you model minimum and high
> efficiency DX cooling and heat pump equipment?
>
> I just posted a question on unmet hours:
>
> https://unmethours.com/question/101487/how-do-you-model-minimum-and-high-efficiency-dx-cooling-and-heat-pump-equipment/
> <https://unmethours.com/question/101487/how-do-you-model-minimum-and-high-efficiency-dx-cooling-and-heat-pump-equipment/>
>
> "I?m trying to get an understanding of the practice of
> modelers when comparing minimum efficiency and
> high-efficiency DX equipment and heat pumps for different
> applications. I know that detailed performance data is
> sometimes difficult to get. How successful have you been
> in trying to get detailed performance data from vendors?
> If you can?t get data like that, how do you model the
> equipment?
> How do you model the indoor fan? If you know it is
> multispeed, how do you figure out those details? What if
> all you have is the AHRI data (EER/EER2, SEER2/IEER, COP
> at 17/47, capacities, full load/intermediate/minimum
> airflows) what assumptions do you have to make? What
> performance curves do you use? If you can get data from
> the manufacturer, what assumptions do you still need to
> make? Is it different for residential size equipment than
> commercial?"
>
> If you can respond to this email or post a response on
> unmethours, I would appreciate it.
>
> Thanks
>
> Jsaon
>
>
> --
> Jason Glazer, P.E., BEMP, GARD Analytics, ASHRAE 209 chair
> Admin for onebuilding.org building performance mailing lists
>
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>
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> ------------------------------
>
> End of Bldg-sim Digest, Vol 209, Issue 2
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--
Jason Glazer, P.E., BEMP, GARD Analytics, ASHRAE 209 chair
Admin for onebuilding.org building performance mailing lists
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