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How to design an occupancy schedule based on Area/person method? what does the fract 0.0 or 0.05 or 0.2 mean?

asked 2017-08-16 10:46:48 -0500

surajtalele gravatar image

updated 2017-08-16 12:29:04 -0500

How to design an occupancy schedule based on area/person or person/area method? What do values of 0.9 or 0.05 or 0.2 mean? How to calculate maximum number occupants in the building based on this criteria of schedule?

And if we decide use directly input the ocuupant number in the building? Then, how to simulate situation were occupants are not present in the building, (for example at night)?

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I am trying to understand the methodology how to setup occupancy schedule based on area/person or person/area and how to identify what is the max number of occupants in the building?

If occupancy calculation method is area/person and schedule is as below:

Until:5:00 0.05 Until: 6:00 0.1 Until: 7:00 0.25

So how to comprehend this? I mean how to identify how many people are in the building until 5 for example?

surajtalele gravatar imagesurajtalele ( 2017-08-16 12:53:23 -0500 )edit

@surajtalele, this answer from last week can probably explain to you the relationship between the people object and the occupancy schedule.

David Goldwasser gravatar imageDavid Goldwasser ( 2017-08-16 13:05:09 -0500 )edit

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answered 2017-08-16 13:18:36 -0500

Hi @surajtalele

The occupancy schedule is based on the % of occupants that occupy a certain thermal zone at a given time. For example, in the weekday occupancy schedule example below, the office thermal zone is 95% occupied from 8am -12pm and from 2pm to 5pm. If you want the space to be fully occupied, you model it as 100% and if you want the space to be completely unoccupied, you model it as 0%.

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This schedule can be modeled using a Schedule:Compact object. You would need to define the occupancy for all days. That is, define the occupancy for design days, weekends, holidays, etc.

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The schedule above modeled in E+ looks like this: (The line that says Through:12/31 means that the same schedule is applied for the whole year. You can break the schedule for different months of an year if it is appropriate for your model.) You can look at an example file or I/O ref guide for details on how to model the ScheduleTypeLimits object for Fraction.

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This schedule can then be applied to the People object. The occupancy schedule does not depend on how the occupancy is defined here. If you know the number of occupants for a thermal zone, it is best to model the occupancy using "People" as the Number of People Calculation Method. Sometimes, the occupancy information is available as occupant density (people/area or area/person) in which case, you can use the other options. Here is a thermal zone where the occupancy schedule above was applied:

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Thank you very much for such a detailed answer. It is very helpful. Only, my question is, if I define the number of people as occupancy calculation method and enter value as 10. and I want to model the zone occupancy at 95% ocuupied area then in schedule the fraction will be entered as 0.95 and to calculate occupancy at that instatnt this fraction will be multiplied by number of people i.e. 0.95 X 10=9.5 which is approx 10 is that right?

surajtalele gravatar imagesurajtalele ( 2017-08-16 13:42:49 -0500 )edit

@surajtalele That is correct. Although 9.5 people cannot occupy a space at a given time practically, this would account for transient occupancy for the space in a simplified manner.

rsunnam gravatar imagersunnam ( 2017-08-16 13:46:59 -0500 )edit

Great.......thank you so much for your answer...... This will be very helpful. Just last suggestion from you. Which option of occupancy calculation method is more scientific.... direct input of occupants or area/person or person/area?

surajtalele gravatar imagesurajtalele ( 2017-08-16 14:32:30 -0500 )edit

I usually input input occupancy as number of people (reflecting peak occupancy). Technically it shouldn't matter how you input the occupancy in the model. However, since we may have small (or large) approximations in the geometry, the calculated occupancy by the model may be slightly unexpected when you use area/person or people/area.

rsunnam gravatar imagersunnam ( 2017-08-16 14:45:27 -0500 )edit

Yes, exactly. That was also my concern, because, while designing thermal zones I have simplified some of th geometrical areas because its irrelevant to provide too many architectural detials in energyplus input. And I specifically have a certain number of occupants in my mind which i would like to consider in simulation. So, direct input looks like a good approach to me.

surajtalele gravatar imagesurajtalele ( 2017-08-16 14:49:43 -0500 )edit

answered 2017-08-16 13:10:43 -0500

There are two things you need to provide to provide hourly schedule for the occupancy. (1.) The peak occupancy value (it's in the LOADS section under People definition (for ex: 200 sqft/person OR 0.005 person/sqft. (2.) The hourly fraction schedule (what you've described) where the values vary from 12am to 12am (generally 24 values for hourly schedule but can increase if you provide 15 min or 1 min scchedules).

Let's assume your space area is 1000 sqft, and the peak occupancy def: 200 sqft/person. The maximum number of people in the space can be = 5 persons (1000/200)

Later you need to define the total occupancy loads to the spaces (or spacetypes) where OS (or any other software) multiplies the peak occupancy (5 persons) to the fractional schedule. Let's say your fractional occupancy schedule is:

12am-5am: 0.0

5am-9am: 0.2

9am-12p: 0.6

12p-5p: 1

5p-12am: 0.4

OS will now multiply the peak occupancy to this fractional schedule to define the number of people in the spaces like this:

12am-5am: 0 person

5am-9am: 1 person

9am-12p: 3 persons

12p-5p: 5 persons (maximum value as the fractional schedule is 1)

5p-12am: 2 persons.

Hope it helps now.

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Great!!! Really helpful... Thank you very much......

surajtalele gravatar imagesurajtalele ( 2017-08-16 13:39:33 -0500 )edit

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Asked: 2017-08-16 10:46:48 -0500

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Last updated: Aug 16 '17