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Radiant Cooling In Panel Rads?

OaklandNS Member Posts: 51
I installed a DIY radiant heating system about 5 years ago with a ton of help from this forum. Following best practices I read about here, I oversized my panel radiators and ended up with a system that keeps everyone extremely comfortable at low water temperatures (the range is 85--115 degrees on my outdoor reset curve currently). I'm working on a solar installation and considering converting to a heat pump system to replace my gas-fired condensing boiler.

Down the road, we are likely to do a gut remodel of the house and I'd likely install ceiling panels to handle radiant heating and cooling (big surface area, low heating temps, high cooling temps). But because the remodel is down the road, I was curious about whether I'd get any cooling benefit from running cool water through the radiators on a condensation control system. Does anyone know if there a mathematical formula that I can use to calculate the theoretical cooling benefit of cool water assuming given air temp, cool water temp, and surface area of the radiators (Runtals) to see if the heat pump might be worth buying sooner than the actual remodel to run off the current radiators?

Radiant cooling seems viable to me because I live in the Bay Area and we don't have much cooling need. We generally only need cooling a few times a year when the outside air temp gets really high. For example, if it's 100 degrees outside my house will top out at 82-85 degrees. It would be great to drop the temp into the 70s. We'd probably use cooling most often to take the edge off/drop the indoor temp by a couple of degrees.


  • hot_rod
    hot_rod Member Posts: 22,348
    Condensation would be one issue. Probably far too little surface area also. Chilled beams, chilled ceiling grids, air handlers, or radiant slabs are a few other hydronic options.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Big Ed_4
    Big Ed_4 Member Posts: 2,818
    Maybe a good dehumidifier may work best for you , 85* no humidity is perfect , welcome to Aruba :)

    There was an error rendering this rich post.

  • Tim_D
    Tim_D Member Posts: 129
    Due to the low position in the space, you will be unable to develop a convective current and will therefore be limited to about 1 btu/sqft of surface per degree of difference between the radiant surface and the space.
  • jumper
    jumper Member Posts: 2,306
    Now that efficient dehumidifiers are available; ceiling radiant cooling can work.
    One can be comfortable in warm dry air when radiant temperature is moderate.