Interpreting SIM reports

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Hi everyone,

Can anyone help me assert or correct my understanding on something? This is from a model built in v3.65, b7175, doe2.2 engine (with intent to upconvert the project to doe2.3 before I'm done).

Report PV-A lists the capacity for each heating/cooling loop. Here I'm cropping to just the loops, and highlighting what I'm used to thinking of as the "peak" coincident capacity requirement for a chilled water loop - 13.909 MMBtu/hr (that's millions):

[cid:image002.jpg at 01D521E8.47C63900]

The following reports PS-H go into more detail on each item listed in PV-A. Here is the report for the same "Chilled Water Loop," with a coule more highlights:

[cid:image003.png at 01D521E8.47C63900]

Immediately, I note that 13.909 MMBtu/hr (1,159 tons) aligns with PV-A, however I do not see that number matching (intuitively) any of the other figures or sums provided on this sheet. The figure 5,625.126 kBtu/hr (469 tons) aligns with my expectations for peak load on the loop, where nominal capacity of the associated chillers on this loop are in the same ballpark (one is 444 tons and one is 210 tons on paper & @ design conditions, and I'm told they commonly do not need to engage the smaller chiller during the dead of summer).

Can anyone help me reconcile the differences between what's reported as "Cooling Capacity" in PV-A, in relation to the annual peak loads indicated for the same loop in the PS-H report?

Thanks!

~Nick

[cid:image005.png at 01D515A3.47EDD880]
Nick Caton, P.E., BEMP
Senior Energy Engineer
Regional Energy Engineering Manager
Energy and Sustainability Services
Energy Performance Contracting
D
M
F
E
913 . 564 . 6361
785 . 410 . 3317
913 . 564 . 6380
nicholas.caton at se.com
15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States
[cid:image006.png at 01D515A3.47EDD880]

Nicholas Caton2's picture
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Hi, Nick.

I think that the capacity of the cooling loop will be based on the sum of
the capacities of cooling coils connected to the loop, assuming the sizing
option for the loop is "secondary" rather than "primary". If you look at
the SV-A report and sum up capacity of all the cooling coils, does that get
you to 13 MBtu/hr? If you want the loop sized based on chiller size, then
the sizing option for the loop should be "primary".

-Erik

*Erik Kolderup, PE, LEED AP*
erik at kolderupconsulting.com | 415.531.5198 | www.kolderupconsulting.com

On Thu, Jun 13, 2019 at 11:02 AM Nicholas Caton via Equest-users <

Erik Kolderup's picture
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Nick,

I'm glad that Erik took the first shot in answering your question, as I
was leery to say too much because I haven't followed the development of
DOE-2.2 much at all and might be giving you outdated impressions from
DOE-2.1E.?? However, your question seems to ask a generic question of
why the design capacities in the verification reports (SV-A, PV-A, etc.)
differ from the peak loads in the simulation reports (SS-H, PS-H,
etc.).?? Design capacities are either input by the user or calculated
using design day conditions which are worse-case conditions, i.e.,
weather conditions at the 0.4% criteria and the building at full
operations for all zones (this is for cooling; for heating the building
is assumed to be completely off except for the HVAC).?? I apologize if
that's all? well known, in which case take this as an extended hello
prior to meeting in KC!

Joe

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Nick,
I wonder if the CAPACITY-RATIO keyword might be having an effect? I?m scanning the Dictionary.

Chris Jones

Chris Jones's picture
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Hi Nick,

The PV-A report deals with the cooling capacity which is the tons of
refrigeration of the chillers total capacity which is coming as 13.909
MMBtu/ hr.

The peak load that PS-H command is giving is the cooling load month wise of
the chiller or cooling coils totally.

As per PS-H report the monthly peak load coming in terms of kBtu/hr is the
maximum cooling load of the cooling coil or chiller that is found on the
peak day of the month. It is sort of maximum cooling load of the month on
the day when there the peak cooling load is observed.

The MMBtu/hr thing priorly observed is the cooling capacity of the chiller
(PV-A) whereas the kBtu/hr thing observed is the maximum cooling coil load
of the HVAC month-wise provided in the PS-H report.

*Thanks*,
Sharad Kumar
Freelancer
India.

......................................................................................................................................

Hi everyone,

Can anyone help me assert or correct my understanding on something? This
is from a model built in v3.65, b7175, doe2.2 engine (with intent to
upconvert the project to doe2.3 before I?m done).

Report PV-A lists the capacity for each heating/cooling loop. Here I?m
cropping to just the loops, and highlighting what I?m used to thinking of
as the ?peak? coincident capacity requirement for a chilled water loop ?
13.909 MMBtu/hr (that?s millions):

The following reports PS-H go into more detail on each item listed in
PV-A. Here is the report for the same ?Chilled Water Loop,? with a coule
more highlights:

Immediately, I note that *13.909 MMBtu/hr* (1,159 tons) aligns with PV-A,
however I do not see that number matching (intuitively) any of the other
figures or sums provided on this sheet. The figure 5,625.126 kBtu/hr (469
tons) aligns with my expectations for peak load on the loop, where nominal
capacity of the associated chillers on this loop are in the same ballpark
(one is 444 tons and one is 210 tons on paper & @ design conditions, and
I?m told they commonly do not need to engage the smaller chiller during the
dead of summer).

Can anyone help me reconcile the differences between what?s reported as
?Cooling Capacity? in PV-A, in relation to the annual peak loads indicated
for the same loop in the PS-H report?

Thanks!

~Nick

*Nick Caton, P.E., BEMP*

Senior Energy Engineer
Regional Energy Engineering Manager

Energy and Sustainability Services
Energy Performance Contracting

D
M
F
E

913 . 564 . 6361

785 . 410 . 3317

913 . 564 . 6380

*nicholas.caton at se.com *

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States

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