[Equest-users] VRV Special case: is it worth modeling?

[Eddie Corwin]

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

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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 )
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
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London ,  SE1 1HF
Tel:  +44 (0) 207 939 0989
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