[Bldg-sim] VRV System Equipment Efficiency

Mon Mar 15 07:49:50 PDT 2010

I understand that ventilation is modeled separately as DOAS, or dummy
outdoor air system for certain hybrid strategies, but would anyone have a
good idea of why dummy zones are modeled, from a building physics
perspective? Thank you.

On 3/15/10, Tim Reynolds <tim.reynolds at cbengineers.com> wrote:
>
>  Gavin is correct that modeling VRV systems as heat pumps will not
> demonstrate efficiencies related to part load operation.  Additionally,
> efficiencies related to heat reclaim during periods of the year when
> applicable will not be captured in the model.  Energy Pro, by Energysoft, is
> the only software I am aware of that has the appropriate algorithms
> programmed to provide accurate simulations.  Energy Pro is a front end
> software package for DOE-2 simulation.  We have used it on several occasions
> to demonstrate anticipated energy savings.
>
>
>
> *TIM REYNOLDS, P.E., LEED AP*
>
> Associate Principal
>
> CB Engineers
>
>
>
> 600 108th Ave NE Suite 600 | Bellevue, WA 98004
>
> T  425 564 8400 Ext 8431 | C 206 422 2547 | F 425 564 8517
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> tim.reynolds at cbengineers.com | cbengineers.com<http://www.cbengineers.com/>
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> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Gavin Gui
> *Sent:* Monday, March 15, 2010 6:54 AM
> *To:* Larry Degelman; Shubhra Kothari; reniel barroso
>
> *Cc:* bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] VRV System Equipment Efficiency
>
>
>
> I agree with Larry. There is no exact system specified in the ASHRAE 90.1
> that matches the VRV system. We used to model the VRV system using the
> efficiencies in Table 6.8.1B, however note that these efficiencies are
> typically for full load operations, hence it will not capture the advantage
> of the part load capability of the VRV systems. I.e. to say, the savings
> calculated as such will be typically conservative.
>
>
>
> Also note that VRV systems are generally waived from the DOE test procedure
> applicable to commercial package air-cooled central air conditioners and
> heat pumps (2 systems that I know of are the Mitsubishi City-Multi and Sanyo
> VRV-III systems) although they have to comply with the alternate testing
> procedure. So just take note of the system efficiencies used for the
> modeling.
>
>
>
> -------------------------------------------------
>
> Gavin Gui
>
> Project Engineer
>
> ERS, Inc.
>
> 120 Water Street, Ste. 350
>
> North Andover, MA 01845
>
> Ph: 978-521-2550, x 236
>
> Fax: 978-521-4588
>
> ggui at ers-inc.com <jrogers at ers-inc.com>
>
> www.ers-inc.com
>
> -------------------------------------------------
>
>
>
> *From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Larry Degelman
> *Sent:* Monday, March 15, 2010 9:24 AM
> *To:* Shubhra Kothari; reniel barroso
> *Cc:* bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] VRV System Equipment Efficiency
>
>
>
> Here's another opinion (non-authoritative): I believe the VRV efficiency
> requirements would match best with the "air cooled, cooling and heating
> modes" requirements in Table 6.8.1B (for heat pumps).  In the ECB method,
> this would most likely be system 8, Packaged terminal heat pumps.  I agree
> that the ventilation should be modeled separately as a DOAS.
>
>
>
> LOD
>
> ===========================
> Larry O. Degelman, P.E.
> Professor Emeritus of Architecture
> Texas A&M University
> ===========================
>
>
>
> *From:* Shubhra Kothari <shubhrakothari at gmail.com>
>
> *Sent:* Monday, March 15, 2010 12:32 AM
>
> *To:* reniel barroso <renielbarroso at yahoo.com>
>
> *Cc:* bldg-sim at lists.onebuilding.org
>
> *Subject:* Re: [Bldg-sim] VRV System Equipment Efficiency
>
>
>
> Well, there seems to be no ARI standard for testing VRV yet. So, you won't
> find it in 90.1.
>
> The closest you can get is packaged single zone (match cooling capacity) i
> believe but you'll have to figure out a way of modelling the fresh air side-
> as DOAS or others.
>
> Thanks
> Shubhra Kothari
>
> On Mon, Mar 15, 2010 at 12:26 AM, reniel barroso <renielbarroso at yahoo.com>
> wrote:
>
> Hi to all!
>
>
>
> Where can we find the Minimum Requirement System Efficiency of a VRV
> System in ASHRAE 90.1?
>
> Which of those systems mentioned in the ASHRAE 90.1 can we use to compare
> such equipment?
>
>
>
>
>
> Thanks
>
>
>
>
>
> Reniel
>
>
>  ------------------------------
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