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Changing setpoints with measure files

asked 2022-09-11 18:40:21 -0500

updated 2022-09-16 14:56:16 -0500

I'm trying to run a measure file on my model. It only changes the thermostat value for some hours in the year's first three months. The problem is first, that loads vary, not only in those hours but throughout the year, even in months with no measure input. And second, it does not specifically lower the demand in hours which the measure decreases the setpoint and vice versa. The Default temp is 21 for heating and I change it to 23 and 18 to increase and decrease the load respectively. Does anyone have an idea of how this can happen?

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answered 2022-09-14 20:59:37 -0500

This leads me to another question to check the effect of hourly thermostat scheduling on the buildings' indoor temperature. Is there a way that the hourly indoor temperature can be reported in the model's outputs?

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You might try adding the following to the .idf file:

Output:Variable,*,Zone Air Temperature,hourly; !- HVAC Average [C] 
Output:Variable,*,Zone Thermostat Air Temperature,hourly; !- HVAC Average [C]
Output:Variable,*,Zone Thermostat Heating Setpoint Temperature,hourly; !- HVAC Average [C]
Output:Variable,*,Zone Thermostat Cooling Setpoint Temperature,hourly; !- HVAC Average [C]

You can then open the eplusout.sql file with DView to see zone temperature vs. setpoints. Is that what you are looking for?

mattkoch's avatar mattkoch  ( 2022-09-16 17:14:01 -0500 )edit

Thank you for the suggestion, Matt! This is actually a way that I can test that the setpoint changing measure files to work correctly.

I can put my main question at a higher level, though. Is there any method, other than the Ruby-based measure files, that I can change setpoints in certain hours automatically?

Mohammad Miri's avatar Mohammad Miri  ( 2022-09-16 19:05:55 -0500 )edit

As you're likely running OpenStudio (re: measures), you can activate the output variables Matt suggested directly in the App (or through the SDK). In addition to plotting setpoint vs sensed temperatures, you could also do a diff between .osm files (before vs after running the measure), as well as checking the eplusout.err file ... i.e., is the measure inadvertently doing more than expected?

Denis Bourgeois's avatar Denis Bourgeois  ( 2022-09-17 06:19:28 -0500 )edit

What do you mean by "changing setpoints at certain hours automatically"? Dynamically e.g., based on runtime variable outputs? If so, EMS would be well suited for this (which you can also define via the SDK).

Denis Bourgeois's avatar Denis Bourgeois  ( 2022-09-17 06:27:39 -0500 )edit

Thanks for the details, Denis. I mean for the setpoint to be set during certain hours (which is already known as an exogenous output) through a series of scripts (similar to what the measure intends to do). As I am facing issue doing it with the measure files, I'm thinking of finding an alternative method.

Mohammad Miri's avatar Mohammad Miri  ( 2022-09-19 13:01:09 -0500 )edit

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Asked: 2022-09-11 18:40:21 -0500

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Last updated: Sep 16