×
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

DOAS systems

DOAS systems

DOAS systems

(OP)
ayone constructed DOAS air conditioning system in real before ? I have a few questions .

RE: DOAS systems

Posting those questions would help us a lot answering them :)

RE: DOAS systems

So......what is your question?

RE: DOAS systems

(OP)
for the following doas :

In the process of design I need to substitute in the following equation linking enthalpy wheel sensible and latent effectiveness with t and w as follows :



The question is : what is meant by capacitance flow rate and minimum pass flow rate ?

RE: DOAS systems

(OP)
for the following doas :

In the process of design I need to substitute in the following equation linking enthalpy wheel sensible and latent effectiveness with t and w as follows :

The question is : what is meant by capacitance flow rate and minimum pass flow rate ?

RE: DOAS systems

As this clearly is a homework question, I suggest you ask your teacher.
Capacitance flowrate is mass flowrate times heat capacity... which probably was explained in class.

this looks like a Semco Pinnacle system.

RE: DOAS systems

(OP)

Quote (As this clearly is a homework question, I suggest you ask your teacher. )


no it isnt homework and not explained in class

Quote (this looks like a Semco Pinnacle system.)

yup
its an ASHRAE paper talking about the design steps of DOAS system coupled with a CRCP .

Quote (Capacitance flowrate is mass flowrate times heat capacity... which probably was explained in class. )

So what does it physically resemble ?
And what do you suggest I shall substitute for Cp with ?
If putting Cp = 1.02 KJ/Kg then whats the point of Cp in the equation if its going to be cancelled in num and den . Cps(Cp and Cp_min) should have different values.But how to find each ?

RE: DOAS systems

Specific capacity of OA and EA could be different. Imagine -15°F OA with almost no moisture, and 70°F EA with a lot of moisture.

What are you trying to do? In most cases the manufacturer would have a software for their equipment that you can use for sizing. You wouldn't know the specific wheel effectivenesses at a specific flowarate anyway.
for example a 3000 cfm ERV has different effectiveness at 2000 cfm than at 3000 cfm.

If you really want to get into detail, I suggest reading up on the Thermodynamics book and use EES





RE: DOAS systems

(OP)

Quote (HerrKaLeun )

If you have done this before . How do you design and size the system in real guys ? I need information from engineers whom have done this allot of times before .

RE: DOAS systems

You need to find an Engineer who does this to give you some help.

You aren't going to get enough design information on a web forum.

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