Representing Hotel Occupancy

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Dear Forum,
Assuming:

. 10 story hotel with 200 guest rooms facing all compass directions

. Each guest room has HVAC and outdoor air from a through-the-wall
heat pump

How can I create a simple modeling scheme and schedules which will reflect
normal occupancy variations?

As I think about it, the reality of operation is quite different than a
central HVAC unit, because random individual rooms can be completely off,
while others are on. Room temperature, ventilation and fan power are all
affected. There will be no predictable pattern for which rooms are unused
or unoccupied. ASHRAE does have some typical use patterns in their 90.1
User Manual but, for example, they assume 100% on time for fans. That's too
coarse for my taste, and will overestimate energy substantially.

I REALLY don't want to model 200 individual zones with varying schedules! I
know that I'm not the first one to wrestle with this idea, so I am hoping
for some creative insight from you.

Thanks in advance!

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Good luck.

This is a common problem, typically nothing is typical. It is all up to
judgment.

The "typical patter" is hard to define. My parents are part owners of the
hotel in a small town. Typically it is empty but it fills up during
holidays, the busiest holiday is Opening Day of Hunting Season. I'm sure
Vegas has a different "typical patter" as does the KC air port hotel, ect.

If I was modeling 200 guest rooms and wanted different schedules I would make
5 schedules. A, B, C, D and E, then assign them to the various guest rooms.
To create the schedules I would suggest talking to the owner, use judgment,
and keep in mind the goal/purpose of the model. [And see what give you the
most point. :-P]

This is just a discussion point but 'Guest rooms' are either occupied or not.
occupancy schedule says 25%, it means that there is 1/4 of a person is in
each office (Happy Halloween!). But offices are usually on a common system.
Each guest room will be independent, so I would assume the guest room
schedules will either be 100% or 0%.

John Eurek PE, LEED AP

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I quickly go through 90.1 UM and notice:

1. As per Appendix G, UM highlights that "these values may be used only if
actual schedule are not know";
2. As per schedule for occupancy -hotel/motel, the percent varies from 90%
(night) to 20% (noon). It is quite reasonable to me provided no actual
schedule are known. I guess you can further reduce it proportionally if you
are able to get more info, such as optimal occupancy rate for the hotel.
3. There is no schedule for fan running 100% but HVAC system. You can
understand it as running 100% on time for HVAC system with occupancy sensors
since you have PTHP providing both conditioning and OA in individual rooms.
Fan power will be calculated with respect to occupancy schedule in this
manner.
4. Bear in mind, your baseline will be PTAC or PTHP for hotel. You
will probably overestimate fan energy savings if you are to use the
by-default schedule (and you believe the real occupancy rate will be
differnt).
5. To me, such schedule is more important and sensitive for M&V modeling. I
will not bother about using by-default occupancy schedule for LEED/incentive
modeling.

Regards,

Cheney

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My hat is off to all of those who responded! I have plenty to think about
and am smarter than I was. All good!

James V. Dirkes II, P.E., BEMP , LEED AP

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Hi James,

You did not say which model you are using so I'll put this in eQUEST
terms. Hotels, motels, and high rise residential buildings will have
very different schedules than offices, etc., because the assumption is
that people are coming and going at different times. If you specify any
one of those building types eQUEST will give you a schedule which is
likely perfectly good for you to use for occupancy, lighting, equipment,
etc. You can at least call it up and then modify it as you see fit, if
you see fit.

With regard to the 100% on time for fans, if you read the help behind
this schedule you will probably find that it is an availability
schedule, not an actual use schedule.

Lastly, just do your best with the schedules, etc., and simplify the
model for yourself as much as you can. If you read in Appendix G about
thermal blocks, this is just the kind of building to look for them in.

Best,

Carol

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Hey folks:

The idea of five schedules or so sure seems to make sense to my feeble mind.
Ask the owner for their, or the hotel management company's occupation
projection and expected event projection and then match that up as well as
you can and have at it.

It varies widely whether or not individual rooms are turned off when
unoccupied based upon many things including but not limited to local weather
(can vary at different year parts whether or not they are turned off between
occupants), local customs, hotel brand/price point, room location in the
structure (low/high, inside/outside and so on), and, none of this deals with
the reality of what type of guest at different week and year parts (business
people tend to get up and leave.).

None of that deals with how are you handling the common areas such as
hallways, event rooms, entry and so on. Again, dependent upon location your
hallways on floors with rooms may have no units or units only at ends and/or
in stairways.

The real question is what is your goal, projecting to some semblance of
reality or points. It if is points I agree with the below, what is most
beneficial :). If it is reality, good luck, because even if you get all of
the above (and many of the companies are very accurate in what they see as
the occupation as that drives their financial decisions) you can't predict
except very roughly what individual room occupants will do. If you cater to
us old folks it will probably be set warmer than if it is others :) and most
certainly resort versus airport versus hunting as noted below will be wildly
different.

Anyway I suggest speak to the owner/hotel management folks about what their
projections are as they typically project for every night although they may
only want to share weekly or monthly occupancy and ask them if they try to
fill lower or upper or by section/wing first.

Thanks

Andy Hoover

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