Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question
3

Implementation of electrochromic window in OpenStudio

asked 2017-08-24 16:55:05 -0600

ADD's avatar

updated 2017-09-08 11:21:07 -0600

I have searched unmet hours to find a way for modeling of dynamic glazing and find out there is a way in EnergyPlus and example called Thermochromic window. In the example, there were different 19 temperatures for windows surface temperatures to change material properties. But instead of giving different surface temperatures I want to define different SHGC values for each phase that may be possible for window properties. Do you have any idea or example to enter different SHGC values? Hope I could define correctly what I want.

edit retag flag offensive close merge delete

Comments

How many states would you like to model? You can use a switchable glazing object if you are ok with 2 states.

mdahlhausen's avatar mdahlhausen  ( 2017-09-12 12:36:26 -0600 )edit

Do you want to change window properties depending upon temperature, or change window properties depending upon SHGC?

Aaron Boranian's avatar Aaron Boranian  ( 2017-09-12 17:35:14 -0600 )edit

I want to model 4 steps depending upon SHGC.

ADD's avatar ADD  ( 2017-09-14 12:00:15 -0600 )edit

1 Answer

Sort by ยป oldest newest most voted
1

answered 2017-09-15 18:14:17 -0600

Let me start by saying that if you are a new user of OpenStudio / EnergyPlus, what you want to do is quite complicated.

In order to change a window construction assembly based upon the SHGC, you can use the Energy Management System (EMS) capability of EnergyPlus. This will require that for EACH window surface, you create:

  • Two EMS:Sensor objects to read the output variables 'Zone Windows Total Transmitted Solar Radiation Rate' and 'Surface Outside Face Incident Solar Radiation Rate per Area' from a window surface
  • One EMS:InternalVariable to read the area of the window surface
  • One EMS:Actuator object to change the Construction State of the window surface.

The remaining EMS objects you will require are:

  • Four EMS:ConstructionIndexVariable object to point to the four Construction objects that define the four window tint states you want to model.
  • One EMS:Program to define the code that determines what the four SHGC values / ranges are where you want to change the window tint state. Be sure to multiply the sensor for "Surface Outside Face Incident Solar Radiation Rate per Area" by the internal variable for window surface area to get the overall radiation rate in W.
  • One EMS:ProgramCallingManager to let EnergyPlus know when to execute the code in the EMS Program.

There is a worked out example of changing construction assembly surface assignment in the EMS Application Guide you can refer to.

Note that this approach will only work if the window construction assemblies are defined as individual layers using WindowMaterial:Glazing and similar objects instead of the WindowMaterial:SimpleGlazingSystem that assumes constant SHGC.

You cannot create or edit EMS objects within the OpenStudio application, so you will need to write a measure to incorporate this. There are EMS objects that have recently been added to the OpenStudio SDK, so you can write an OpenStudio measure instead of an EnergyPlus measure.

edit flag offensive delete link more

Comments

I have gone through that EMS example for Thermochromic glazing to understand the idea behind EMS. I will try your steps. Writing measure seemed to me as another option if I decide to use openStudio instead of EP. But I am not so experienced to write measure for now. Thank you so much.

ADD's avatar ADD  ( 2017-09-18 15:44:00 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Training Workshops

Careers

Question Tools

1 follower

Stats

Asked: 2017-08-24 16:55:05 -0600

Seen: 979 times

Last updated: Sep 15 '17