[Bldg-sim] Representing Hotel Occupancy

[Jim Dirkes]

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

 

 

The Building Performance Team
James V. Dirkes II, P.E., BEMP , LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: Cheney [mailto:chenyu73 at gmail.com] 
Sent: Friday, October 21, 2011 1:34 PM
To: Jim Dirkes
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Representing Hotel Occupancy

 

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

 

LinkedIN @  <http://ca.linkedin.com/pub/yu-cheney-chen/27/637/72b>
http://ca.linkedin.com/pub/yu-cheney-chen/27/637/72b 





On Fri, Oct 21, 2011 at 8:51 AM, Jim Dirkes
<jim at buildingperformanceteam.com> wrote:

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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Tolerance is not agreement.  Tolerance is precisely the willingness to
restrain from the use of coercion. (and who hasn't experienced the benefit
of respectful, constructive disagreement?)

 


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