×
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

VE considerations for new Courthouse.

VE considerations for new Courthouse.

VE considerations for new Courthouse.

(OP)
Hi, I have been working with an earlie design (Design/development phase) for a new Courthouse and the engineers suggested some VE Items. The problems is that I am not sure of what he or she really wants. Here are the VE items.

1. Specify R-134 chiller in lieu of R-123 chillers.
   ~~The design has 2-250Ton water cooled chillers. The narrative suggest the usage of centrifugal chillers. In my understanding I should use screw chillers in order to change my gas to R-134. No taking in considaration other future costs, does the present cost of a screw chiller will be lower than a centrifugal chiller?

2.Provide outdoor air varaible volume intake fan system   in lieu of outdoor air preconditioning unit.
~~The design has an OA AHU of 10KCFM. They want to replace the preconditioning unit with an AVV(air varaible volume)intake fan. Does this will affect the performance of my AHU's? Do I have to change the capacity of the unit that  is connected to this OAAHU?

3.Use draw-out type breakers vs. insulated case power breakers in main distribution switchboards.
Like I said at the beginning, I am working with DD drawings, therefore I do not have a complete breakdown of the different power distribution equipment. The building will have an estimated load of 4Kamp@277/480V service. It will have Switchboard,Switchgears as the MDPE 's(main distributions panels). What will be the difference of an average percentage in cost between a draw-out type and an insulated case power breakers type braekers?

4. Add UV filter on AHU's.
 What is the difference in cost and use between an UV filter and a HEPA filter?
.

RE: VE considerations for new Courthouse.

1. There are centrifugals for R134a but they run at higher pressres than that of R123. You can have better capacity control with centrifugals particularly if you have VFD and antisurge controls. Screw chillers are relatively cheaper.

2. If you are not pretreating the outside air then you have to do it in your AHUs and it is one and same either way. Moreover, variable volume outside system is not an alternative for outside air preconditioning system. It may be that you have to equip your outside air preconditioning system with variable volume system.

3. Not an expert on this. Electric Power Engineering is the right place to ask.

4. It may be a UV bank. HEPA filters can stop bacteria to some extent from entering into the area but you have to use disinfectants to kill them later. UV light kills bacteria but it can't take care of particulate matter where as HEPA filters do this effectively. Cost difference is irrelevant.

Regards,


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