Dan,
[I copied the equest-users instead of bldg-sim.]
You need to enter zone-level OA as OA-FLOW/PER and/or OA-FLOW/AREA. The
OA flow/per (person) is what will vary the OA on an hourly basis, based
on your occupancy schedule(s). (Hourly OA = (# of people) * OA-FLOW/PER
* (% occupancy in schedule)). In order to turn OA off during unoccupied
hours, I create a MIN-AIR-SCH, coinciding with the fan schedule, set to
zero when fan is off (or night cycling) and -999 when fan is on. The
hourly OA can be verified by creating a new hourly report for the system
to track total system supply air flow rate and ratio of outside air to
total supply air.
Regards,
Bill
William Bishop, EIT, BEMP, LEED(r) AP
Dan,
eQuest cannot properly model ASHRAE 62.1 outdoor air rates, as it takes
the maximum OA value from OA-FLOW/PER or OA-FLOW/AREA, not the combined
sum as required by ASHRAE 62.1. However there is a very tedious
workaround to this. Using your occupancy schedule, you need to
calculate the total OA requirement (area and person) for each hour, and
enter that into your zone OA schedule as a fraction of the design flow
of the RTU (OA cfm / RTU cfm). Basically, you need to replace all the
-999 values to a desired hourly fraction value. Unoccupied hours should
be set to zero. You need to repeat this for every OA schedule in each
hvac zone that has DCV. Do not use the 'DCV zone sensors' option, as it
is useless in this case. Use the default (should be 'Fraction of Design
Flow'). It gets messy if you have more than one occupancy schedule.
Regards,
VICTOR YEUNG, BASc, LEED(r) AP