×
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

Radiantly heated floor with vav terminal units

Radiantly heated floor with vav terminal units

Radiantly heated floor with vav terminal units

(OP)
    I have not used this forum before and hope this is an appropriate subject.
    I am searching for suggestions for control strategies.
Setting:  Child's reading room in a to-be-built public library.  The room will have hydronic radiant floor heat and a dedicated vav terminal unit for heating, cooling and outside air ventilation.  The floor is concrete structure. The total concrete slab thickness under the room is 6 1/4".  There will be 2 1/4" of concrete, 2" of rigid board insulation, the PEX tubing and 2" of concrete on top.  The radiant system has a dedicated pump.  The building will have a DDC control system.
Problem:  How to integrate control of the radiant floor and vav systems without providing heating and cooling simultaneously and/or having the systems fight each other.  I am considering maintaining the slab at a varying temperature dependent on outside ambient dry bulb and allowing the pump to come on only below a predetermined outside temperature.  The vav would provide primary heating and cooling.
I hope I've provided enough information for responses.  If anyone has successfully put a similar system together I would like to hear about it.
Thanks, Tim

RE: Radiantly heated floor with vav terminal units

I have not designed any system quite like that one, but I have a few thoughts you may want to consider.  First of all, the floor heating, I'm assuming, is for comfort of the kids (or adults) sitting on the floor.  If that is the case, you may want to set a certain temperature to maintain the floor, independent of air temperature.  If this is a ground floor, the ground temperature may cool the concrete below what is comfortable certain times of the year (depending on location).  Alternatively, there is a method (I believe the ASHRAE Fundamentals book describes it) to determine the appropriate place to turn on baseboard heating if you have a heat pump.  Modeling the floor heating as the heat pump, you may be able to use the same method to determine what limiting factor you want to use for the VAV system in fall and spring (and even winter, depending on location).  Hope this helps some.

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

eBook - Mastering Tolerances for Machined Parts
When making CNC machined parts, mastering tolerances can be challenging. Are general tolerances good enough? When does it make sense to call out for tighter tolerances? Do you need a better understanding of fits, datums, or GD&T? Learn about these topics and more in Xometry's new e-book. Download Now
eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close