HVAC Climatic Design

[KZ001]

Can someone define “coincident 1% outdoor ambient dry-bulb temperature”? Thank you!

 

[317069]

Read ASHRAE, or your course book

 

[willard3]

The definition is in the term:

>>co·in·ci·dent adjective \-sə-dənt, -ˌdent>>: happening at the same time

>>Full Definition of COINCIDENT


>>: of similar nature : harmonious <a theory coincident with the facts>

>>: occupying the same space or time <coincident events>

 

[KZ001]

Thank you willard3!

I was not sure if 1% means that the design temperature has been exceeded only 1% of the time during the year or the design temperature occurs only 1% of the time during the year. However, I think that my first assumption is correct. Please let me know if I am wrong. Thanks!

 

[EnergyProfessional]

i can't decipher the coincidence language... but typically you use the 1% and 99% percentile of the climate data, which will represent a design OAT for heating and cooling.

If you use 1%, 99%, 99.6% is up to what you want or the owner wants, or code prescribes. Code also may prescribe something in addition. Here in WI the ASHRAE recommendation is -11°F (based on 1% i believe), code requires -15°F... so following the percentile rule is moot since you need to meet code.

 

[MintJulep]

It's the average dry bulb temperature that goes along with (coincides with) the design Dew Point or Humidity Ratio numbers.

Used for the design of evaporative coolers or dehumidification equipment.

 

[KZ001]

HerrKaLeun and MintJulep Thank you!