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Time Not Comfortable Based on Simple ASHRAE 55-2004

asked 2015-05-04 00:41:43 -0500

LiHan's avatar

updated 2015-05-04 08:13:53 -0500

Have someone knew how to reduce the time not comfortable based on simple ASHRAE 55-2004? Which variables influence the time?

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Welcome @LiHan. Please edit your question to include a tag for the software you're using so that others can benefit from it. Also, if you're asking about unmet load hours see this previous question.

MatthewSteen's avatar MatthewSteen  ( 2015-05-04 08:12:24 -0500 )edit

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answered 2015-05-04 08:47:47 -0500

updated 2015-05-04 08:50:07 -0500

Read the input/output reference manual section relative to People. You should also take a look at ASHRAE 55 directly. If you want to see how parameters affect whether it's comfortable or not, you can try the CBE Thermal Comfort Tool which is actually cited by the Input/Output reference.

Factors that come into play in the calculation:

  • Operative temperature, taken as the average of the air temperature and the mean radiant temperature. ASHRAE 55-2004, appendix C, says that this is true if the relative air speed is small (<0.2 m/s, 40 fpm)
  • All of these parameters under the People object:
    • Clothing level (clo): typical is 0.5 in summer and 1.0 in winter
    • Air velocity schedule
    • Activity level (met): Metabolic rates, depends on the type of activity is done in the space, for example 1.0 for "seated, reading or writing", 1.2 for "filing, seated", or even 5 to 7.6 for basketball playing.
    • Enable ASHRAE 55 comfort warnings: you have to enable which people objects you want to report comfort warnings.
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May Thx! It's very helpful to me!

LiHan's avatar LiHan  ( 2015-05-04 09:07:52 -0500 )edit

Make sure you upvote and mark the answer as accepted if you're satisfied, so the question gets marked as answered. See the help page for more information.

Julien Marrec's avatar Julien Marrec  ( 2015-05-04 09:33:47 -0500 )edit

@Julien In EnergyPlus, how do I track which variables actually cause the uncomfortable state? By tracking each variable in each uncomfortable hour (through detailed variable outputs)? Also, is there a reason why the ASHRAE 55 Comfort warning has different results from the "Zone Thermal Comfort ASHRAE 55 Simple Model Summer Clothes Not Comfortable"?

kirakatsui's avatar kirakatsui  ( 2023-01-04 23:51:47 -0500 )edit

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Asked: 2015-05-04 00:41:43 -0500

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Last updated: May 04 '15