[Equest-users] VRV Special case: is it worth modeling?
Eddie Corwin
ecorwin at altanova-energy.com
Thu Oct 14 10:41:49 PDT 2010
Omar, attached is an example .inp file (when opening, make sure you are viewing
INP files, and not PD2 files only)
You need to change your system to PVVT, then go throughput an setup the proper
inputs (fan power, schedules, condenser type...). There is one issue that I ran
into, and that is the following:
On the first tab, labeled "Basics", there is an option that says "WL/GS Heat
Pump" I selected YES (because selecting NO gave me unrealistically high
results), even though it is an air-to-air heat pump. After reading through the
literature, this does seem to be a proper selection, as long as
your condenser is set to air-cooled. After that, just make sure you have the
proper curves (Daikin can provide you curves for their unit).
Let me know if you run into more problems, but don't be afraid to dive right in.
-Eddie
________________________________
From: Omar Katanani <omar at ecoconsulting.net>
To: Eddie Corwin <ecorwin at altanova-energy.com>;
Gary.Schrader at buildings.schneider-electric.com
Sent: Thu, October 14, 2010 12:14:36 PM
Subject: RE: [Equest-users] VRV Special case: is it worth modeling?
Thanks a lot guys!
The EER of the VRV is 10 (I had read it wrong).
COP= EER / 3.412
EQUEST asks for Elec. Input Ratio (inverse of COP). So I assume the EIRis
3.412/10 = 0.3412… correct?
As for modeling the VRV:
Can you please detail to me how to extract the performance curves from
Residential VVT and how/where to input them? I don’t have heating in my VRV
system (zones served are elec rooms & UPSrooms)? I have attached my file in this
email. Would it be possible to help me by roughly inputting data into 1 of the 4
zones (I called the systems: VRV-1, VRV-2, VRV-3, and VRV-4)?
If any of you helps me with this I can submit my simulation results and report
by mid-next week, and this would be awesome and I’ll be grateful!
I know each one of us is busy, but Eddie gave me the impression that it would
take a couple of minutes to fill the inputs! If you think that would take more
time, I would much appreciate it if you detail to me what should I do as much as
possible!
Many thanks again,
Omar
___________________________
Omar Katanani
Sustainable Design Engineer
Email: omar at ecoconsulting.net
EcoConsulting (Lebanon)
NahasBuilding, 4th floor
4 St-Maron Street/ Georges Haddad Avenue
Postal Code: 2028 5806 SAIFI
Beirut, Lebanon
Tel: +961 (0) 1 971 266
Mobile: +961 (0) 3 045 045
EcoConsulting (UK) Ltd
28 Marshalsea Road
London, SE1 1HF
Tel: +44 (0) 207 939 0989
Fax: +44 (0) 207 939 0981
Website: www.ecoconsulting.net
-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Eddie Corwin
Sent: 14 October 2010 18:28
To: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] VRV Special case: is it worth modeling?
For the most part, I agree with Gary. I believe that you will also find
significant savings from part-load performance from the VRV system. VRV
systems operate more efficiency at part-load, especially when compares to a
chiller. I just finished modeling a VRV system, and with the newest version of
eQuest, it is not that difficult. Simply use the PVVT system, and set the
compressor to variable speed. You will need a low-speed curve for both heating
and cooling. I took those curves from the ResidentialPVVT system.
I also agree that a COP of 10 seems unreasonable, but I assumed that you meant
an EER of 10
-Eddie
________________________________
From:"Gary.Schrader at buildings.schneider-electric.com"
<Gary.Schrader at buildings.schneider-electric.com>
To: omar at ecoconsulting.net; equest-users at lists.onebuilding.org
Sent: Thu, October 14, 2010 11:10:43 AM
Subject: Re: [Equest-users] VRV Special case: is it worth modeling?
Omar,
The only thing that would save you a significant amount of energy in my opinion
would have been scheduling large VAV air handling and plant equipment that was
originally serving them. I had a project where I took data closets off of the
VAV units and put VRV units in the closets so that the VAV units no longer had
to run 24/7. Scheduling these large VAV units had a significant savings impact.
In your case, it sounds like you may have something similar but I would need
clarification. You said that your closets (that you want to convert to VRV) are
currently FCU. I assume that these FCUs are served by chilled water. By
switching these closets over to VRV, are you able to now schedule the chiller
off? If yes, I would assume that significant savings would result by not running
a chiller (and pumping) 24/7, even with a high unloading capability and
variable-speed pumping. (If you had low unloading capability and constant
pumping, more savings would result)
At face value, simply changing the efficiency of the cooling equipment isn’t
enough to evaluate energy savings. If, however, you can significantly change the
schedule of plant equipment because it is isolated from zones that require 24/7
operation, savings could be significant and I would certainly recommend a model.
Sidenote: 10 COP seems very, very high for even the best VRV equipment. I would
check that value to ensure accuracy…
Best luck,
Gary
_______________________________________________________________________________________________________________________
Gary Schrader| Schneider Electric | Buildings Business | Energy Solutions |
Engineer I
Phone: +1 913 217 8068 | Fax: +1 913 469 0206
Email: gary.schrader at buildings.schneider-electric.com | Site:
www.schneider-electric.com/buildings | Address: 16011 College Boulevard, Suite
212 , Lenexa , KS 66219 , USA
*** Please consider the environment before printing this email.
________________________________
From:equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Omar Katanani
Sent: Thursday, October 14, 2010 5:41 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] VRV Special case: is it worth modeling?
Dear all,
My school has some 200 zones including classrooms, storage rooms, offices...
The HVAC system is a VAV one, with FCU for 17 offices/storage rooms.
In the new updated design, 4 of these FCUs were replaced with a VRV system. I am
about to model that:
Do you think that these 4 small zones (electrical room (x 2), UPS room,
telephone room) will significantly change the Space Cooling results (not that no
heating is required)? I mean, these zones had FCUs and were conditioned. All
that changed is that a VRV (COP=10) replaced the chiller (COP=5.4) for only 4
zones!
I would like to avoid the complexity of modeling VRVs if possible!
Many thanks,
Omar
___________________________
Omar Katanani
Sustainable Design Engineer
Email: omar at ecoconsulting.net
EcoConsulting ( Lebanon )
Nahas Building, 4th floor
4 St-Maron Street / Georges Haddad Avenue
Postal Code: 2028 5806 SAIFI
Beirut, Lebanon
Tel: +961 (0) 1 971 266
Mobile : +961 (0) 3 045 045
EcoConsulting ( UK ) Ltd
28 Marshalsea Road
London , SE1 1HF
Tel: +44 (0) 207 939 0989
Fax: +44 (0) 207 939 0981
Website: www.ecoconsulting.net
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