[Equest-users] eQUEST - serious trouble with LEED review

Omar Katanani omar at ecoconsulting.net
Thu Jan 27 07:38:12 PST 2011


Thanks Bill & Ravi,

 

Assigning to the secondary loop fixed the problem.

 

I have a couple of extra questions:

 

1.	The Loop Design DT for the Primary CHW loop is 10F, as per the
Mechanical specifications. I was wondering if I need to put the same
number for the Secondary CHW loop. Shall I put the Secondary CHW loop
design DT to be 10F, or should it be zero ( in order not to consider the
delta 10deg twice) ?
2.	I have more than 1 secondary CHW pump in my design.  However, it
seems that I can only specify 1 secondary CHW pump. Any suggestions? (I
currently have 1 pump with the capacity kW and flow (gpm) equal to the
sum of the proposed secondary pumps.

 

Many thanks for your continuous help,

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 <http://www.ecoconsulting.net/> 

 

  

________________________________

From: Bishop, Bill [mailto:wbishop at pathfinder-ea.com] 
Sent: 26 January 2011 21:04
To: Omar Katanani; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] eQUEST - serious trouble with LEED review

 

Omar,

You have to assign your systems/coils to the new secondary loop. They
are currently all assigned to the primary loop.

Bill

 

________________________________

From: Omar Katanani [mailto:omar at ecoconsulting.net] 
Sent: Wednesday, January 26, 2011 12:58 PM
To: Bishop, Bill; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] eQUEST - serious trouble with LEED review

 

Oh and 1 more thing,

 

I am getting an error once I do perform a run. It says:

 

            "Secondary Chilled Water Loop has zero design flow. Check
input for consistency, or specify design loads."


Any idea of what may be the reason?

 

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 <http://www.ecoconsulting.net/> 

 

 

________________________________

From: Omar Katanani 
Sent: 26 January 2011 19:26
To: 'Bishop, Bill'; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] eQUEST - serious trouble with LEED review

 


Dear Bill,


 


Many thanks for your feedback. I am really grateful!


 


Attached are updated screenshots as per your email. Please find my
questions/comments below:


 


*       For "Secondary CHW Pump.JPG", there appears to be a conflict in
the "Capacity Control" input box with your previous email:


 


If you check the help function of "Capacity Control", you get the
following:


CAP-CTRL


Accepts a code-word that defines how the pump modulates as the flow
varies. When you specify NUMBER to be more than one,  then the pumps
will first stage according to the load and then modulate capacity
according to the CAP-CTRL mode:

ONE-SPEED-PUMP        The pump rides its curve as the flow varies (2-way
valves in at least one system are necessary for this to happen).

TWO-SPEED-PUMP        The pump can operate at two speeds. The low-speed
is determined by MIN-SPEED. You should choose MIN-SPEED to match the
actual low speed ratio of the pump, typically 0.67 or 0.5.

VAR-SPEED-PUMP        The pump has a variable frequency drive. The
minimum pump speed is specified by MIN-SPEED. Note that a pump's speed
is not usually proportional to flow; speed is a function of both the
pump flow as well as the pump head requirement. If the pump head
requirement does not fall off as the square of flow (for example, when
the pump has a fixed head setpoint), then the pump will operate at a
speed higher than it would otherwise.


As per Appendix G, my conditioned area is less than 11,148 m2, therefore
the secondary pump must ride the curve. According to the DOE help above
(underlined), 2-way valves must be selected in order for the pump to
ride its curve. You said in your email that 3-way valves are required if
the pump rides the curve. 


*       Shall I input 3-way or 2-way valves for the "Valve Type" of the
secondary chilled water loop ("Secondary CHW Loop.JPG")?


 


In total, there are 3 inputs which I need to make sure of and hereby
request your kind comments:

 

1.	Air-Side HVAC System Properties > Cooling > CHW Valve Type
2.	Secondary Chiller Water Loop > Basic Specifications > Valve Type
3.	Secondary Chiller Water Pump > Basic Specifications > Capacity
Control

 

 

Thanks again!

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 <http://www.ecoconsulting.net/> 

 

 

________________________________

From: Bishop, Bill [mailto:wbishop at pathfinder-ea.com] 
Sent: 26 January 2011 18:10
To: Omar Katanani; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] eQUEST - serious trouble with LEED review

 

Hello Omar,

 

I assume you are doing a LEED model using ASHRAE 90.1-2007, Appendix G.
(2004 is not much different.) My comments below apply to modeling the
baseline.

 

*	Correct, CHW pumps attached to chillers should be constant flow.
Appendix G does not specify if condenser water pumps should be variable
or not. I would argue for constant flow since G3.1.3.11 specifies
two-speed fans for tower capacity control.
*	Correct, two pumps per chiller and none for the primary CHW
loop. However, you need to create a secondary CHW loop and pump and
control it per G3.1.3.10.
*	Correct, use a single HW pump on the HW loop and none for the
boiler(s).
*	Correct, subtype for a primary CHW loop should be "primary". The
secondary CHW loop that you need to create will be "secondary". For the
baseline, "secondary" sizing is correct, since you are not specifying
chiller capacity manually.
*	CHW valves at the system/zone coils should be 2-way if the
secondary CHW loop pump is variable speed, and 3-way if the pump rides
the curve. G3.1.3.10 tells you which way to model the secondary CHW
pump.

 

Regards,

Bill

________________________________

From: Omar Katanani [mailto:omar at ecoconsulting.net] 
Sent: Tuesday, January 25, 2011 4:12 AM
To: Bishop, Bill; Heinrich.ib-bauklima.de;
equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] eQUEST - serios trouble with LEED review

 

Dear Bill,

 

I hope I understood your email properly. 

 

Please find attached 3 printscreens of my Baseline input.

 

*       For the "Chiller Loop Attachments.jpg", is the "Flow Ctrl"
correct? i.e., Constant flor for the Chiller Water Pump and Variable
Flow for the Condenser Water Pump

*       For the "Water Side.jpg", is the number of pumps correct on the
left tab? i.e., 2 for each chiller and none under the Chilled Water Loop

*       I assume that I do not have to do the same for the Hot Water
Loop, right? Should I create 1 pump under each boiler?

*       For the "Chilled Water Loop.jpg", is the Loop Subtype (Primary)
and the Sizing Option (Secondary) the correct inputs?

 

I set my CHW Valves to 2-way valves as per your email..

 

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 <http://www.ecoconsulting.net/> 

 

 

________________________________

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Bishop,
Bill
Sent: 24 January 2011 20:49
To: Heinrich.ib-bauklima.de; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] eQUEST - serios trouble with LEED review

 

Heinrich,

 

The chiller pumps requirement your reviewer is referring to is in
Section G3.1.3.11 (not G3.1.11). The model you sent currently has one
primary CHW pump attached to each of your two chillers, a separate
primary CHW pump on the primary loop, one secondary CHW pump and one
condenser water pump. You labeled your primary chiller pumps "Secondary
Pump CHW 1" and "Secondary Pump CHW 2", which is probably why the
reviewer thinks you only have one primary pump (the one on the primary
CHW loop labeled "Primary CHW Pump"). I suggest making the following
changes:

*	Delete the separate pump attached to the primary CHW loop
*	Relabel the chiller pumps to indicate they are primary loop
pumps
*	Add condenser water pumps for each chiller through the "Loop
Attachments" tab of the chillers; delete the other CW pump.
*	Change both the primary loop and secondary loop sizing option to
"secondary" to allow eQUEST to size based on coil loads.
*	Change the chiller capacity ratio for each chiller to 0.50. (Or
use 0.575 if you want to oversize by 15% per G3.1.2.2 - I don't know if
this is supposed to apply to chillers.) Each chiller will be sized for
half the total load.
*	Allow the chiller capacity to default (remove the 0.9 MBtu/h).
*	Make sure you include both/all pages of the PS-C report - your
reviewer will then see that the secondary CHW pump is variable flow.
(Your zones have two-way valves already.)
*	The PV-A report will show that the total primary CHW pump flow
will nearly match the secondary CHW pump flow.

 

Regards,

Bill

 

William Bishop, PE, BEMP, LEED(r) AP | Pathfinder Engineers & Architects
LLP

Mechanical Engineer

 

 134 South Fitzhugh Street                 Rochester, NY 14608
T: (585) 325-6004 Ext. 114            F: (585) 325-6005

wbishop at pathfinder-ea.com           www.pathfinder-ea.com
<http://www.pathfinder-ea.com/> 

P   Sustainability - the forest AND the trees. P 

________________________________

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of
Heinrich.ib-bauklima.de
Sent: Monday, January 24, 2011 12:28 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] eQUEST - serios trouble with LEED review

 

Hi Everyone,

 

I got a review comment that got me in big trouble and I can't find the
solution yet.

May be there is no solution for this in eQUEST....!

I rate this forum as the very best address for difficulties with eQUEST
and LEED EAc1 simulation.

So please give me some guidance and feel free to testthe model attached.

 

Hereare the two comments of the reviewer.

"It appears as if the pumps and circulation loops were not modeled
correctly for the Baseline Case. It appears based on the PS-C reports
that there is only one primary chilled water pump and one condenser
water pump for the Baseline Case. However, ASHRAE 90.1 Section G3.1.11
requires that each chiller be modeled with separate condenser water and
chilled water pumps interlocked to operate with each associated chiller.
Please model two primary chilled water pumps and two primary condenser
water pumps in accordance with Section G3.1.11. Also update the chilled
water valves to two-way valves so that the secondary chilled water loop
operates as a variable flow loop with pumps riding the curve. Provide
updated PS-C reports confirming that the changes have been made."

"It is unclear why the pump flow for the secondary chilled water loop is
so much larger than that of the primary chilled water loop when the
temperature differential for both loops is expected to be the same. It
also appears based on the outputs in PS-C that the secondary chilled
water loop is operated at the same load for every hour that it is on
even though it is a variable speed pump. Please update the secondary
chilled water loop flow to be consistent with the primary chilled water
loop flow, and confirm that the secondary chilled water loop is
operating as a variable flow loop."

 

I have to say:

I didn't see any equest-model modeled with separate condenser water and
chilled water pumps interlocked to operate with each associated chiller.


I manually resized the boilers and chillers with reference to SS-D
report, because auto sizing of eQUEST generated capacities that were
double the size of SS-D report. Resizing of the volume flow of secondary
loop of chillers according to primary loop of chillers generated
warningmessages but changed nothing.

 

Heinrich

 

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