Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Zone air supply temperature

asked 2023-11-16 02:36:32 -0600

Iby's avatar

updated 2023-11-16 12:55:24 -0600

Hi, can someone please explain why the zone heating design supply air temperature is 50°C? see link: I expected the figure to be near the room set point temperature to be around 21 °C. Thanks

edit retag flag offensive close merge delete

1 Answer

Sort by » oldest newest most voted

answered 2023-11-16 14:34:29 -0600

50°C (122 F) is not unusual (as an initial default value) for zone heating supply air (especially for older designs), although 30°C to 35°C (~90F) is preferable. It may be higher than 50°C in some cases, yet I think 50°C is a code-set maximum temperature for insulated ductwork (foamed plastic insulation). ASHRAE 90.1 requires a maximum supply of 11°C above setpoint (e.g. 32°C if setpoint is 21°C). In any case, a decrease in heating supply air temperature involves a proportionate increase in airflow rate - a balance that would depend namely on peak heating loads IMO.

edit flag offensive delete link more


Many thanks for your explanation. I will take a look at the Ashrae document you referenced above.

Iby's avatar Iby  ( 2023-11-17 07:36:27 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2023-11-16 02:36:32 -0600

Seen: 70 times

Last updated: Nov 16