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Use of Outdoor Air Reset in OS/EPlus Chilled Water Loop

asked 2014-09-22 08:28:05 -0500

dannyllim gravatar image

updated 2017-04-18 08:39:55 -0500

Appendix G Section G3.1.3.9 Chilled-Water Supply Temperature Reset (Systems 7 and 8) requires that chilled water supply temperature be reset based on OA db temperature according to the schedule: 7 deg C at 27 deg C and above, 12 deg C at 16 deg C and below, and ramped linearly between 7 deg C and 12 deg C at temperatures between 27 and 16 deg C. Among the setpoint managers available in OS 1.4 is the Outdoor Air Reset SPM which I think can implement the foregoing schedule according to the logic shown in the Engineering Reference. However, my concern is the description for this SPM which says it is an outdoor air strategy for supply air temperature and does not mention it can be used also for nodes where water is flowing. I tried running my model using this SPM in my chilled water loop and the results viewer shows that for OA db temperature fluctuating between 21 and 30 deg C, chilled water supply temperature is kept between 7 and 10 deg C which is what I want to see. Looks okay but is there something I am not aware of? Will the LEED reviewer find this okay?

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@dannyllim. I don't have enough Karma to retag this question, but please use the tags openstudio and energyplus rather than oseplus so that this gets picked up appropriately.

__AmirRoth__ gravatar image__AmirRoth__ ( 2014-09-22 11:00:12 -0500 )edit

Thanks for the reminder Amir and thank you Neal for retagging.

dannyllim gravatar imagedannyllim ( 2014-09-22 18:51:25 -0500 )edit

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answered 2014-09-22 12:58:24 -0500

Archmage gravatar image

Don't worry, such setpoint managers are intended to work on plant loop nodes as well as air systems.

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answered 2014-09-22 14:17:54 -0500

updated 2014-09-22 14:18:54 -0500

If your hourly results are showing that it's functioning properly I wouldn't worry about it. I've used the OA Reset SPM on both HHW and CCW Plant Loops in OS to comply with Appendix G/LEED and in my limited experience haven't heard of reviewers picking this one apart since they cannot verify it without detailed - i.e. hourly - results. Ultimately all the reviewer will see is that you've properly selected the OA reset schedule in the Table 1.4 XLS file to document compliance.

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Thanks Matt and Archmage for your quick answers.

dannyllim gravatar imagedannyllim ( 2014-09-22 18:43:48 -0500 )edit

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Asked: 2014-09-22 08:28:05 -0500

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Last updated: Sep 22 '14