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Building was Built in the 70s What would I use for Design OA and Infiltration

asked 2024-05-14 15:53:21 -0500

DSMEAEP's avatar

updated 2024-05-16 06:23:09 -0500

First time using this EnergyPLus and Openstudio. Currently I am trying to model a school building in the 50s with an extension built in the 70s. Below are some of my questions:

  • The building is mainly window A/Cs, how would I model these
  • For heating the Unit ventilators have OA intakes that periodically open, how would I model this?

Thank you so much!

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answered 2024-05-17 13:10:57 -0500

If you are looking for the efficiency level and air flow rates that make sense for a building that age you might want to take a look at reference buildings that NREL has modeled for pre-1980. The models are for reference buildings but the assumptions made in them might help you figure out the assumptions for both questions. My instinct is that a window A/C unit from that era has a 6 EER to 8 EER for efficiency when new. With the amount of maintenance that window A/C unit usually get, the efficiency probably has dropped significantly since the units were new.

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I imported the pre1980s library and used the values for the building type for infiltration

DSMEAEP's avatar DSMEAEP  ( 2024-05-17 15:28:36 -0500 )edit

answered 2024-05-17 11:39:20 -0500

Greg Estep's avatar

updated 2024-05-17 11:40:00 -0500

For window AC, use PTAC. For the unit ventilators, I would use PTAC with outdoor air supply. If the unit ventilators have energy recovery device, then you will need to use an air loop and an AHU. You then use schedules to control the OA.

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The UV are connected to a hydronic boiler loop with 2 boilers. Im gong to attempt to model that in a bit - in the loop do I need to include both boilers? Simple question probably I know but Im not entirely sure. I see that there is a heating only unit ventilator option in the zone equiptment. Any reason I shouldnt use that aside from the OA damper issue?

DSMEAEP's avatar DSMEAEP  ( 2024-05-17 15:27:39 -0500 )edit

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Asked: 2024-05-14 15:53:21 -0500

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Last updated: May 17