Fellow eQuesters,
I'm sorry to continue posting such basic questions, but I am, as usual,
lost.
It seems that entering data for lighting and for HVAC (in the detailed
model) involves hundreds of fields, many of which really don't seem
relevant. For example, the lighting fields include many questions about
photometrics. However, obviously, if I have a lighting time schedule and
the lighting systems defined, I should be able, using simple arithmetic, to
calculate how much energy it uses. However, eQuest wants a bunch of other
information (such as photometrics), which has taken me forever to calculate.
However, I dare not omit such data since I don't know what eQuest's
algorithms are.
I am just starting to model the HVAC systems and things appear even
worse. I don't need eQuest to design the systems for me. The systems exist
on paper. How do I eliminate all of the irrelevant fields and just enter
the important stuff that actually describes my systems? I am especially
perplexed when there are three fields asking for A, B, and the ratio of A to
B. Why doesn't it just ask for two rather than all three such data? What
if a user enters conflicting data, such as A=2, B=3, and A/B=7? Again, it
is alot like the lighting: I don't care about CFM/person or CFM/sq-ft. I
have the CFM, the number of people, and the square feet for a zone. How can
avoid the hundreds of questions?
Any ideas? How can I tell what fields eQuest will actually use in doing
the energy modeling so that I can ignore the rest?
Lars Fetzek, EI
Good questions ...
First to lighting - I typically do not enter all of the photometric info.
I simply enter the lighting power density (W/sq-ft) for each of my model
spaces. I think you will find this is typical of most modellers.
Spreadsheets help here.
Second, to HVAC - most of those fields are there so you can enter one of
them depending on the information you have. You are quite correct you
don't need to enter cfm/sq-ft if you have cfm -- just put in cfm and leave
the rest. Similarly, for OA -- if you put in values for OA cfm,
cfm/person and cfm/sq-ft, eQUEST will use the cfm value and ignore the
cfm/person and cfm/sq-ft values.
You can calculate fan energy as either kW/cfm OR static pressure x flow
(divided by a constant and total efficiency).
Another note - when it comes to HVAC, many fields can be entered at both
the system and zonal level. Zonal takes precedence. (i.e if you enter a
total system cfm and some zonal cfm then the remainder of the system cfm
values is distributed proportionally between the zones without zonal
values entered). This is especially notable for OA as the wizards put the
OA values to the zones.
Look to your output reports -- especially the SV-A report for HVAC to show
you how eQUEST is interpreting your HVAC entries.
Good luck.
Lars,
I'm intrigued by this - I've never had to input photometric data. What
exactly was it asking you for?
With regards to your second question, you typically specify only one
(either cfm/person or cfm.ft2 or total cfm). If you have issues with
any of these commands try right clicking and going to either topic help,
or item help for more specific help. eQUEST has pretty good help files.
For instance when you go to item help under the Outside airflow, you get
the text below:
OUTSIDE-AIR-FLOW
The minimum flow rate of outside ventilation air for the zone.
Alternatively, or additionally, outside air flow rate may be specified
by the keywords OA-FLOW/PER and OA-CHANGES (or by
SYSTEM:MIN-OUTSIDE-AIR). The program calculates outside air flow rate
based on each entry and normally uses the larger value except if it sees
data entry for OUTSIDE-AIR-FLOW, which overrides other values. Note that
specifying outside ventilation air at the zone level takes precedence
over specifying it at the system level. Although the specified
quantities may be modified by the program for the sake of consistency,
the flow of outside ventilation air is an uninterrupted flow as long as
the fans are operating. The outside ventilation air quantity is not
determined by the design space heating or cooling demands except when an
economizer is specified. Use either OUTSIDE-AIR-FLOW or OA-FLOW/PER or
OA-CHANGES.
Hope this helps
Vikram Sami, LEED AP
Vikram,
In answer to your question - in the "space properties" section, it asks
for illuminance (footcandles), ceiling-to-luminary distance (feet), and
workplane height (feet). In the "lighting systems" section, it asks for
total lamp lumens and for the coefficient of utilization.
That having been said, B. Fountain has kindly addressed my question.
The upshot is that the photometric data is not necessary or relevant if use
the "luminaire count" lighting data input method in the "space properties"
section and have properly defined the electrical power used by each lighting
system. The photometric data is relevant only if I intend eQuest to
calculate the quantity of fixtures necessary to enforce a certain level of
illumination.
As for your advising me to right-click for help - thanks very much!
Previously, I went to "help" through the menu system, which gives me just
about nothing.
Lars Fetzek, EI