Hourly space temperatura after cooling

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Hi all,

If I open the BEPS Building Energy Performance, there are 155 unmet hours. I would like to get the temperature values throughout the year after cooling, but the only related option that I can see is the SS-O Space Temperature Summary where the temperatures above the set point are much more than the unmet hours. It seems that is the report of the space before cooling.

How could I get the space temperature after cooling to have relation with the unmet hours?

Kind Regards,

Paul Caicedo

Mechanical Engineering Consultant

IntegralMECH

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SS-R will tell you what zone is throwing unmet hours.

SS-F will show you which month the unmet hours are occuring in for that/
those zone(s) and the corresponding max and min temperatures.

SS-O shows you the time of day when it occurs.

In SS-O, this is the space temperature after heating and cooling is
applied for hours when the fan schedule is on.

From there, you may wish to create an hourly report on the zone
temperatures or unit supply temperatures and airflows.

Other items to check:
- fan, heating and cooling schedule
- night ventilation control -- cycle on any?? - stay off (in which night
setback temperatures may not be met)
- throttling range
- thermostat action (reverse action?? proportional?)

155 hours is not very many to worry about.

Brian

On 22/03/2019 9:51 a.m., Integral Mechanical Engineering Designs via >

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Hi David,

Thanks for the answer. I don?t think that explain the data because the system is working most of the time during the year, and a note in the SS-O report shows that the temperature counts are made only for the hours when the fans are on. The cooling schedule matches with the occupancy schedule.
[cid:image002.png at 01D4E17B.EA656E90]
The set point is 75 ?F and the throttle range is 2 ?R.
[cid:image003.png at 01D4E17C.85F7A260]
The BEPS report shows that are 155 unmet hours, but the SS-O report gives a value of at least 2505 (adding from 80-85 and above 85).

Kind Regards,

Paul Caicedo

Mechanical Engineering Consultant

IntegralMECH

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Hi Paul,
The 75 ?F input that you shared below for "Indoor Design Temperature" is the DESIGN-COOL-T which is used for sizing calculations (and is optional when using DOE-2.3). The hourly thermostat setpoint is part of the thermostat schedule so you need to look at the day schedules within the S1 Sys1 (PSZ) Cool Sch.
Regards,
~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

[Pathfinder-EA-logo-2]T: (585) 698-1956 F: (585) 325-6005
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Paul, others,

Being an old DOE-2 user, I would recommend getting the hourly reports for zone
temperature, setpoint temperature,? and cooling load, and then aggregating these by hour
of day and month, i.e., get 12 average hourly profiles by month, which would tell you
what's going on. I don't know if there's an hourly report variable for unmet load, but it
should be detectable as hours where the zone temperature exceeds the setpoint
temperature.? I know how to set up hourly reports in DOE-2, but? don't know how can be
done in eQUEST.

Joe

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Thanks Joe!

Your participation prompts me to ask the question that is at the heart of
this discussion - it looks like an attempt to "reverse engineer" a
definition. We have all done it. FYI - and it's a massive but educational
time pit. Does anyone [Joe] know the programmed definition for eQUEST,
[probably from DOE2] on unmet hours?
*i.e DOE2 will mark an Unmet hour if a zone is: Outside the throttling
range? How many degrees outside range (.1, 1 etc)? Plus Occupied? Plus Coil
capacities are exceeded? Plus Any other conditions?*

Agreed about the hourly reports. The hourly one for eQUEST that I use is
under thermal zone for the "amount of load that's unmet" for an hour.
Include the zone temperature that hour and that should get you what you
want (but possibly not what you need). There is probably an unmet hours
flag to enable (0 or 1), but I might be thinking of the wrong software
package? I try not to look at individual unmet hours for spaces - the
space/zone is usually not the actual problem.

A few notables from the images sent:

- Fans are running over 7500 hours per year. I doubt the building is
occupied that many hours.
- Schedule seems to be a default schedule from the wizard? Defaults like
this are often unoccupied on weekends and 12 hours per day.
- That would be around 3000 occupied hours.
- Similar default schedules allow 82 degrees for unoccupied hours -->
Possibly >5500 hours requiring 85 to be outside the throttling range, and
they are unoccupied

Best Regards,

Bob

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Hello,

Thank you for all your answers. There have been really helpful, and the problem was that I had 90 ?F in the day schedules within the S1 Sys1 (PSZ) Cool SCH (different value as mentioned by Bill). The solution was to correct the value to 75 ?F, and now the unmet hours match with the SS-O report.

Kind Regards,

Paul Caicedo

Mechanical Engineering Consultant

IntegralMECH

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Good for you! But now my OCD is triggered.

To repeat the question if anyone is just looking at this email:

Does anyone happen to know the computational definition of an unmet hour
for eQUEST? Especially as stated:

*i.e DOE2 will mark an Unmet hour if a zone is: Outside the throttling
range? How many degrees outside range (.1, 1 etc)? Plus Occupied? Plus Coil
capacities are exceeded? Plus Any other conditions?*
I guess I can dig for it, but it's likely one of you knows this officially,

Bob
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On Tue, Mar 26, 2019 at 10:28 AM Integral Mechanical Engineering Designs

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The DOE-2 help file for BEPS plant report provides context on unmet hours (similar language for HEATING):
HOURS ANY ZONE ABOVE COOLING THROTTLING RANGE is the percentage of hours when the temperature in any conditioned zone is above the zone thermostat?s cooling throttling range by more than 1?F. This is a measure of the HVAC systems? ability to hold zone thermostat set points. Note that, in a given hour, it does not matter how many zones are above the cooling throttling range; as long as at least one zone is above the throttling range, the hour is counted. For this reason, the value may or may not match the total shown in report(s) SS-F and SS-R.
Additional background provided by Steve Gates on 21-Jan-2010:

Throttling range is the temperature band between no output and full output,
with the setpoint in the middle of the range. If the VAV cooling setpoint
is 76F with a throttling range of 2F, then the VAV box is at minimum position
at75F, and at maximum at 77F.

The BEPS and BEPU reports count hours as outside the throttling range if the
zone temperature is more than 1F outside the temperature band. In the above
example, a zone greater than 78F or less than 74F would be considered out of
control.

~Bill

William Bishop, PE, BEMP, BEAP, CEM, LEED AP
Senior Energy Engineer

[Pathfinder-EA-logo-2]T: (585) 698-1956 F: (585) 325-6005
bbishop at pathfinder-ea.com www.pathfinder-ea.com
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I have a training/teaching topic I?ve delivered around the subject of unmet hours? it includes this definition (my technical understanding):

An unmet hour is reported when a zone?s hourly temperature diverges from the thermostat setpoint/setback temperature by at least the throttling range + 1?F.

Further, because this definition in isolation (and the associated reference manual entries on the topic) can lead other astray without further context, I immediately follow this definition with the following:

A popular misconception is that throttling range is a panacea for resolving unmet hours.

Tweaking throttling range in isolation however is rarely an effective "treatment" for unmet hours in practice. It does not address any of the most common root causes/resolutions for unmet hours (to my experience):
? Inadequate capacities:

* airflow
* heating
* cooling
* Emphasis for inadequate airflow: Where a model relies heavily upon auto-sizing, airflow by far the most common capacity issue I?ve encountered when troubleshooting.
? System / conditioning availability (scheduling / night-cycling / lockouts)
? Assumptions / errors for the inputs concerning the interior & envelope loads being handled by the systems
? End-user vs. interface errors in developing/tweaking thermostat schedules within the eQuest interface.
? Thermostat schedules being automatically assigned from wizards and therefore reporting unmet hours where comfort isn?t truly being measured/maintained in real life (i.e. does anyone really care if a garage gets warm in the summer?).

This isn?t really a ?computational? response in hindsight, but I had this material at-hand to easily share. Hope this helps in any case!

~Nick

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I agree with Nick?s points. I find adjusting the baseline model minimum heating flows takes time. I have many models where zones need a higher minimum flow than 0.4cfm/sf, 30% in 90.1-2010. I also question the use of REVERSE ACTION thermostats for the baseline VAV box control. I have only come across one building with reverse action VAV boxes.

Christopher R Jones, P.Eng.
T+ 1 416-644-0252

[cid:image002.png at 01D4E3FF.7EF02520]

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Spoke too soon. The PNNL manual promotes Dual Maximum control for VAV boxes. But it doesn?t apply to the baseline.

Christopher R Jones, P.Eng.
T+ 1 416-644-0252

[cid:image001.png at 01D4E400.3111F3A0]

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I can't confirm this, but my recollection is that DOE-2 will report an
unmet hour anytime the zone temperature exceeds the thermostat setting
plus the throttling range, if that's defined.

Joe

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