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When to use summer and winter design day profiles in the schedule definition of openstudio?

asked 2014-11-24 07:22:11 -0500

Xandrika gravatar image

updated 2015-09-29 07:39:25 -0500

I am defining some new schedule sets for my small hotel model in Nepal. My particular concern is how to represent the occupancy rate in the hotel that changes from season to season.
From the tutorials I learned how to define Run Period Profiles for different period. But I also saw the option of defining Summer and Winter Design Day profiles and could not find any information about this option. For what purpose does this option exist? What would be the appropriate approach to represent ocupancy rate in hotel: Summer/Winter Design Day Profiles or Run period profiles?

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answered 2014-11-24 07:40:58 -0500

updated 2014-11-24 07:53:36 -0500

The Design Day profiles you've seen are Sizing Period profiles used for HVAC system sizing. See the docs on Design Objects for clarification, and also the schedules documentation on Day Types which tells you what types of day you can specify in a schedule.

There must be at least 2 (up to any number) SizingPeriod objects present. Normally one will be for summer conditions and one for winter. The summer day should normally have the field Day Type set to SummerDesignDay. The winter design day should normally have Day Type set to WinterDesignDay.

So to answer your question, no these aren't normally used to represent schedules for entire seasons. You should probably build up a compact schedule.

Edit: This is an explanation from the EnergyPlus end of things. I don't really use OpenStudio so perhaps someone else can explain exactly how it applies there.

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OpenStudio uses design day schedules in the same way as EnergyPlus. You will need them for sizing HVAC equipment but they are not applied during the annual simulation. OpenStudio has a graphical schedule editor for creating schedules and choosing when they apply during the annual simulation, see this link for more details.

macumber gravatar imagemacumber ( 2014-11-24 09:45:41 -0500 )edit

More generally, OpenStudio basically is EnergyPlus. That's a gross oversimplification not to mention a mixing of metaphors and comparison of incomparables, but from a modeling standpoint OpenStudio essentially exposes EnergyPlus capabilities. It is not an energy simulation engine in and of itself.

__AmirRoth__ gravatar image__AmirRoth__ ( 2014-11-24 10:44:08 -0500 )edit

How can I define COMPACT SCHEDULES in Openstudio? I could not find any compact schedule in one of the templates.

I was also wondering where to apply this COMPACT SCHEDULE in my model. I guess in the schedule set in Hours of Operation. Am I right?

However, I am not yet clear on how to apply the occupancy rate of a hotel in OS/Energyplus schedules. In the OS schedule it is all about a daily profiles. For Example: If the occupancy rate is 70%. Only 70% of the room are occupied and I would like to run the indivudual HVAC Split System in a room ONLY the time when it is occupied.

Xandrika gravatar imageXandrika ( 2014-11-26 05:32:41 -0500 )edit

It looks like this video will take you through the process link.

Jamie Bull gravatar imageJamie Bull ( 2014-11-26 05:42:45 -0500 )edit

On the second question, you'd probably need to set up a schedule for each room and have the occupancy as either 100% or 0%.

Jamie Bull gravatar imageJamie Bull ( 2014-11-26 05:53:55 -0500 )edit

answered 2014-11-30 11:32:40 -0500

@Xandrika there are several questions floating around in this thread

1) hours of operation is an OpenStudio only schedule, it is not used by EnergyPlus, it is meant to be used by OpenStudio measures

2) OpenStudio allows you to specify a schedule at the building schedule set level. This is applied to all spaces below (unless those spaces override the building level default). Normally, a single schedule representing an average occupancy (e.g. occupancy = 0.8) is acceptable. However, it sounds like you need 0 or 1 only schedules in all spaces such that the area weighted average will come out to 0.8. OpenStudio does not have any mechanism to do this. You could probably write an OpenStudio measure to do this or use EnergyPlus EMS objects.

3) OpenStudio does not yet support Schedule:File but that is on the roadmap to add soon.

4) OpenStudio uses an object call OS:ScheduleRuleset to define schedules, this is equivalent to but different from Schedule:Compact in EnergyPlus. OpenStudio uses its own format in order to support the graphical schedule editor.

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@macumber Several questions: you are right. Therefore, I opened a new thread about the hotel occupance rate here Thanks for your answer. I am not a programmer and I have never written a OS measure. I am thinking to work something out similiar to the seasonal changes in OS school templates. I know that you can define schedule set on building level. But I am wondering what output variable I have to address. With such "building operational schedule" I would like to overide all schedules.

Xandrika gravatar imageXandrika ( 2014-12-01 11:55:23 -0500 )edit

Hey @Xandrika, there isn't a single schedule that you can use to change all the other schedules. So the best approach for you would be to create seasonally varying versions of the lighting, occupancy, equipment, and all other schedules. It just up to you to make sure the seasons line up correctly between all the schedules.

Thanks for sticking with the learning curve on this, I think you are getting close. Also, just because you aren't a programmer doesn't mean you can't write a measure, they are really pretty easy! Once you get a few models under your belt you should try one out :-)

macumber gravatar imagemacumber ( 2014-12-01 14:16:55 -0500 )edit

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Asked: 2014-11-24 07:22:11 -0500

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Last updated: Nov 30 '14