Does any one know how the "PERCENT OF HOURS ANY SYSTEM ZONE OUTSIDE OF
THROTTLING RANGE" from detailed output BEPS is calculated? I am
assuming it is the maximum total number of ours any given system zone is
not within the throttling range divided by 8760. If this is true, why
can't I seem to find the total number of hours from any of the reports
to give me this percentage? Any information concerning this is greatly
appreciated.
David Dowling
David,
There is a lot of speculation on this, and unfortunately I'm going to add to
it.
At a recent training, Marlin Addison explained that the denominator hours is
equal to the fan hours on on the SS-E report.
In DOE-2 Help file I found this definition within the BEPS REPORT on the
"Percent Hours...":
"...is the percentage of hours when the temperature in any conditioned zone
is outside the zone thermostat's throttling range. This is a measure of the
HVAC system's ability to hold thermostat setpoints."
Based on the "any conditioned zone" clause, I'd speculate that the numerator
is similar. In both cases, the program is looking across the building for
each hour to determine if any fan is on and if any zone is out of range.
This procedure could be used to determine the percentage, but I dont have an
easy way to verify it...
Regards,
Rich
David,
?
If several zones have the unmet hour?at the same time, it is counted as one unmet hour instead of several unmet hours for each zone. DOE-2 report SS-F shows the unmet hours for each zone.
?
I hope this will help
?
Shaojie?
Thank you for pointing this section out, it explains this concept very
clearly and I have attached it for reference if anyone else is having
the same problem.
This is explained on page 108 of 135 from the "Detailed Simulation
Reports Summery" under the tutorials and reference menu under help:
"HOURS OUTSIDE THROTTLING RANGE:
The denominator used for this % calculation is the # of hours at least
one system is running. For example, a bldg with two fan systems running
12 hrs/day & 7 days/wk with identical start/stop hours will yield 4380
total fan hrs (8760 / 2). If the start & stop times for one of these fan
schedules is shifted one hour (+/- one hour but still 4380 hrs on each
fan), the new total fan hrs = 4745 (4380 + 365). Total fan hours are
reported on SS-E as Hours Fans ON' (includes night cycle control hours,
if any).
To calculate the total number of hours outside the throttling range,
multiply the percentage reported here by the 'Hours Fans ON' reported on
SS-E.
IMPORTANT NOTE:
Any hours outside throttling range that occur during night cycle control
hours are included in the total hours outside throttling range implied
in the percentage above. Any hours outside throttling range that occur
during night venting hours or during natural ventilation hours are
excluded.
To investigate any hours outside the throttling range, see SS-R, then
SS-F, and SS-O to isolate the system & zone (SS-R), time of year (SS-F),
and time of day (SS-O) the control problems occur. In eQUEST's Detailed
Interface, see also the Air-Side Summary report."
David Dowling