×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Manufacturer Extended Performance Data

Manufacturer Extended Performance Data

Manufacturer Extended Performance Data

(OP)
The "extended performance" data published by manufacturers is apparently linear. In the back of Manual S they show a linear equation to recreate performance data tables.

When you plot the actual published performance data on a graph, it is also - apparently - linear.

However DuPont published an interesting .pdf that shows R410a after about 105F ambient starts to drop off in a VERY non-linear manner.

http://refrigerants.dupont.com/Suva/en_US/pdf/k05738.pdf

(See page 2).



So what can I conclude except the manufacturer performance data is misleading above 105F?

What do you think.

RE: Manufacturer Extended Performance Data

I think you should stay within the published data.  Outside the "wire" is an unknown territory.  Without testing, you just don't know.  I would never spec a piece of equipment that has to operate at the very limit of it's envelope.  If your calcs are wrong, you can only go down.  Pick a unit that operates in the middle of its range, so you have some "wiggle" room, up or down.

RE: Manufacturer Extended Performance Data

(OP)
That is one of the puzzles I'm trying to solve.

a) An existing R-22, 5 ton residential unit is replaced.
b) The new R-410a system does not cool as well at high temperatures.
c) Why. It seems to keep happening.

I have plotted 30 published extended performance data from a single manufacturer, and found no unit in the past 40 years deviates from the average performance by more than 2,500 BTUs at any outdoor ambient temperature (published data from 75F through 125F).

However I still am puzzled why the performance data are all straight lines, when R-410a clearly loses capacity within the published data ranges.



Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources