Radiant floor could be a liability in the long run?

Discussion in 'Radiant Heating and Cooling' started by TJamesW, Dec 25, 2012.

  1. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    As Mark above.

    We have a 406 system running radiant cooling. Our particular concern for this house wasn't the actual cooling. It has a considerable amount of glass and sits on the top of a mountain here. So heat was the main concern and radiant is a great answer.

    BUT, if the homeowner's left all there blinds open for a week in summer, they would be hard pressed to get the heat out of that large house; thus, radiant cooling was a great fit. They also have an HRV on a timer for fresh air and hydronic fan coil mainly for the dehumidification.

    But, all our radiant houses have ducting for fresh air (code). Except maybe the odd old leaky house that tore out their wood boiler. The benefit for our region, is we can downsize that ducting to only serve cooling and/or fresh air loads. About 1/2 our heating loads.
     
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Will do Doc, I do not think we will use the 406 for cooling as we have a pair of chilled water high velosity units that are zoned with Arzel.

    The advantage that I see for possible use of radiant for cooling is running a small pump instead of a big blower motor. Guess I'll go see what new stuff Robert Bean is up to on radiant cooling.

    Mark
     
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Our peak cooling load is about 50% of the peak heating load, and only 10% of the total annual load. But we also get a healthy amount of humidity from the lakes. I guess once you go down the path where you have ductwork in the house, I don't see the need to deal with the complexity of controlling the dew-point. So why do you put in the 406 if you don't use it for cooling?
     
  4. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I too have issues with Lake Erie humidity as you know.

    I have been building this system for over five years. The house is served by a pair of 5 ton water to water units with the loops in a pond. When the economy tanked we picked up a Crown boiler because some one needed cash flow. We got it below the wholesaler's cost. The boiler is our backup aux heat.

    Basement and first floor are both radiant. The second floor is served by one of the two HV air handlers. Most of the time the heat pumps can handle the load but in winter we need more BTUH than we have and we add the boiler.

    I did not install a buffering tank between the heat emitters and the heat pump, at the owner's request and my objection. That will change next month. Adding the buffer to the system will allow me to pipe the heat pumps to the tank instead of the individual air handlers and the radiant floors. The current piping requires that if I turn on the boiler I need to turn off the heat pumps.

    I will, with minor piping and an additional pump, be able to have the pump that feeds water from the hot boiler loop to the cooler geo loop system become a variable speed injection pump.

    The 406 along with 315 wiring center will:

    Stage the heat pumps and the boiler and allow for full boiler without heat pumps with a button push. That is desirable due to very low coast natural gas from the customer's co-op.

    Handle the seven zones in the home in heating and cooling.

    Control all of the pumps and actuators.

    Having to trace all the controls through miles of wire, relays, aquastats and a few zone panels and the Arzel boards

    At least that is the plan as of this writing. I will keep you posted.

    Attached is a photo of the mechanical room.

    Mark
     

    Attached Files:

  5. TJamesW

    TJamesW Member

    Mark that is quite impressive. Clearly well thought out and executed.
     
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Thanks. Except the owner kept changing how we were going to control things.

    It is simpler than it looks. That is all copper. I now use CPVC and draw the piping by hand or in visio.

    Mark
     
  7. TJamesW

    TJamesW Member

    I'd like to avoid the gypcrete pour. That leaves me with the laid out plywood (?) strips in between the hose. Maybe with the metal sections. Is there a preferred material other than ply or OSB or does it not matter much? This would work and the hardwood could be nailed right to the ply / whatever. I would imagine a warm wood floor would earn me points with the Mrs.
     
  8. Injecting a little levity here. Doc, If we could control the dew point we could probably turn off the Lake Erie snow machine. Let us know if you figure it out!:rolleyes:
     
  9. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    T:

    I do not have pictures of the dry floor my customer installed in Avon, OH as a WIP, but you are correct we table sawed OSB into strips and found some cheap steel heat transfer plates. The plates go in the grove then add pex. You do not care if you nail the hard wood nails through the plates just the pipe. He floored it with air in the pipe in case he hit the pex.

    I will try to find you a how to link. Points with others is also good. You are a troll?

    I am attaching a pic of the Avon mechanical room.

    Mark
     

    Attached Files:

    Last edited: Dec 29, 2012
  10. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I like the snow! I moved to Buffalo for the weather!
     
  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Mark, why so any pumps?
     
  12. TJamesW

    TJamesW Member

    Well then it seems that the radiant floor is a solid choice for heating. I suppose I should start another thread on the type of AC system to use in this instance.

    Sure appreciate the help all-
     
  13. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Doc:

    The customer changes his mind. 6400 square feet house and 4000 +/- walk out basement.
     
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Well, I meant that you seem to put a small circulator on each Zone circuit, and also one for each heatpump. I moved to 1 variable speed pump for the load side and all the zones, and either have thermostatic valves or motorized valves controlled by thermostats. Example in the link below.

    Temperature and Energy logging by: Web Energy Logger



    James, no matter what you do if you want A/C you need some kind of ductwork to reduce the humidity.
     
    Last edited: Dec 30, 2012
  15. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    And no matter what you do, you still need ductwork for fresh air (at least it's code around here). The benefit being you can now size ductwork for the smaller loads of cooling/fresh air vs. heating.
     
  16. TJamesW

    TJamesW Member

    Thank you both. Standard ducting but smaller. I like that.

    Thanks-
     
  17. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Doc:

    Like your comments to Dan about pumping piping, I need the pumps for control. BTW there is over 3.5 miles of pex in this home.

    TjamesW: Look at Unico.

    Mark
     
  18. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Doc:

    After the review you where asking about the Avon project and I was explaining about the Valley City Project.

    My bad.

    The Avon job picture with all the pumps was the customer choice. The house is spray foam insulation so we are yet to need to add aux heat. The customer knows and likes pumps so he chose that over ECM pumping and zone valves. The pumps are all the same and he liked the redundancy of being able to chose a zone and swap out a pump in case of a failure.

    I cross threaded my threads.

    Mark
     
  19. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I moved more and more to the WILO stratos pumps and zone valves. You can debate wether to go with one or two pumps for redundancy. They have been amazingly reliable and efficient. We run the entire load side of the heatpump and 20-30 zones on a single WILO.
     
  20. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Doc:

    I get both sides of this idea. I present both and let the customer pick what he likes.

    I think I may start a thread on the Tekmar 406 conversion.

    What do you think?

    Mark
     

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