a crazy radiant cooling phone call today

hot_rod

new home, the builder installed pex in the concrete ICF (foam block walls) A heat pump chills water to 50F, runs through the pex.

Hot humid home, so the builder brings by a dehumidifier. Exposed pex in the attic dripping.

I can't imagine the 2" of foam on the inside of those blocks will allow much wall cooling? 97°F today, probably more energy going outside than in.

I told him to get the load calc and design from the builder/ installer.

Maybe I should just link him to some mini split sites

Mark Eatherton

These situations are going to happen until the wannabe's realize that Dew Point is real, and that radiant cooling can NOT address the latent needs of cooling. And it's things like this that give our industry a bad name. All because someone didn't do their home work.

If you don't have time to do it right, where are you going to find time to do it a second time...

Let me know if you need help with him HR. I'd be glad to help.

I just went back and re-read your post. Radiant walls in an ICF form? Really?

ME

SWEI

What is the control strategy managing chilled water temp? Outdoor reset with dewpoint management is pretty much a minimum here.

Wait -- they ran the PEX inside the insulation? Yikes. Is there a DOAS of some sort?

hot_rod

I'm not sure I want to get in the middle of this one. If no load or design was performed, I think he has plenty of ammo for a potential lawsuit.

I've bumped into this builder before. He build a handful of SIP homes with his "clever" SIP design. He built the SIPS with metal studs and metal joists with 4 or 6" foam between, no wood.
It sounded like a good idea until sun comes up!
Those homes pop, bang, and creak for 20- 30 minutes when the sun hits the roof panels with all that metal tied together trying to expand. Same at night when the building metal cools down. Back to the drawing board

ChrisJ

I don't understand the point?
To me, dehumidification is just as important if not often more important than the actual cooling when it comes to air conditioning.

If radiant cooling can't provide dehumidification (and I hope it can't... wet floors sounds bad) then it seems useless.

Mark Eatherton

Chris, radiant cooling has been used commercially for over 20 years. Residential applications are becoming more common, but it does require a plan of attack, and this one is obviously missing major components. And yes, dehumidification is critical, and in most cases (but not all, obviously) is handled separately by a MUCH smaller air handling system.

Cooling with radiant can in fact address the larger of the two loads (in most cases...) which is the sensible load, and a primary factor in maintaining good human comfort. People experience radiant cooling effect all the time and don't realize it. When you walk from upstairs to down stairs in a home with a basement, your brain can sense the lower MRT and feels comfortable, even though the air temperature is the same downstairs as it is up stairs. It has been proven many times over that radiant cooling with a proper DOAS (if necessary) and a separate system to address internal humidity can result in a significant reduction in parasitic energy cost/consumption. Like up to 50% reductions.

But in order to have it work correctly, a lot of critical math has to be done and details followed. Just because it worked in your brain doesn't mean it will work in the field. Sounds like this guy has had numerous entreprunerial seizures and needs to go to Uponor school to learn the BASICS of radiant/hydronic cooling AND heating.

I hate to admit it HR, but I think your suggestion about mini splits is probably appropriate. That or some small hydronic air handlers connected to his existing system. This builder needs to be straightened out, by someone.

In cases where the latent energy is minimal at best (Colorado, Arizona, New Mexico) dehumidification is still critical because the dew point can change in a heart beat due to fast moving thunderstorms and internal gains. It can be ignored, but will cause discomfort during parts of the year, and that doesn't fit the description of human comfort.

Robert Bean has a class on radiant cooling at Heatspring.com He helped to construct the charts, graphs and manuals for Uponor, and ASHRAE.

ME

ChrisJ

When I was at the eye doctor yesterday it seemed like a minisplit was on, and yet I couldn't hear it. Can they run the fans that slow?

Mark,
Still seems strange. My window units are dumping so much water out right now it's impressive to say the least.

SWEI

Modern minisplits can be amazingly quiet.

The basic idea here is to use the radiant system to cool the structure so the ducted or ductless system only needs to be big enough to manage the air. In a typical commercial space, the demands on that air system are almost entirely driven by occupancy, which opens up significant opportunities for controls optimization.

Rich_49

The direction homes are going Chris radiant cooling makes loads of sense . Radiant tubing can be used to heat and cool . When dew point in the home is high dedicated outdoor air systems or the ventilation systems most tight houses are requiring can handle the latent load . Even in our swampy damp environment like NJ inside dewpoint in new tighter homes does not align with the outdoor Rh but even if it did an evaporative coil can be brought online to handle that load , this coil could be within the ventilation scheme .

Now houses only have to have ductwork to ventilate and manage moisture . We can sell more and by the way better systems since people can be made aware that they don't also have to do forced air or feel as if they have to make a choice contrary to what they really wanted . Radiant .

ChrisJ

Rich said:

The direction homes are going Chris radiant cooling makes loads of sense . Radiant tubing can be used to heat and cool . When dew point in the home is high dedicated outdoor air systems or the ventilation systems most tight houses are requiring can handle the latent load . Even in our swampy damp environment like NJ inside dewpoint in new tighter homes does not align with the outdoor Rh but even if it did an evaporative coil can be brought online to handle that load , this coil could be within the ventilation scheme .

Now houses only have to have ductwork to ventilate and manage moisture . We can sell more and by the way better systems since people can be made aware that they don't also have to do forced air or feel as if they have to make a choice contrary to what they really wanted . Radiant .

Awesome.
But how does all of this come into play with forced hot dust owning something like 90% of the market?

Too many Americans prefer cheap over quality and it seems to be getting worse.

Mark Eatherton

When energy become scarce, it becomes extremely expensive, and THAT is when our light will shine.

In the mean time, we sell COMFORT with extreme efficiency, and there is a BIG difference in the comfort delivered by a forced error system versus a hydronic radiant system.

I've been doing it (up selling versus F.A.) for over half my life. If I can do, ANYONE can do it. First hand experience (having a hydronic/radiant system in your own home for example) goes a long ways towards convincing the consumer that your idea is worthy of their investment, and it IS an investment. An investment in their health, their financial health, and the health of the environment.

In all the years I have been in this industry, I have found that the one way to get the consumers attention is to grab their wallet. As soon as you start taking money out of their wallet, they become VERY interested in conservation... Conservation of their own money.

I only hope it happens in my life and time... But trust me on this, it WILL eventually happen.

ME

4Johnpipe

@ChrisJ The homeowners don't know and the builders either don't know or know and don't care. Well most of them. When we get educated then we become the educators...Nobody else will.

hot_rod

I agree John, completely.

What I have discovered is the ones that need the education most, never show up or even think they need education.

Another classic example are some of the online purveyors of radiant and hydronics.

Mark Eatherton

I honestly believe that this is one of the major reasons that the RPA is being held back membership wise. Too many internet "experts" out there telling people that it's not rocket science. He who has the best SEO wins, and when everything goes to heck in a hand basket, it's not the purveyors fault. Ever. Last time I did a Google search on radiant, the RPA site was MANY pages down.

TImes they are a changing, but when it comes to education, our job (RPA) has just begun, and we've only been doing it for 20+ years...

Heat and comfort are dependent upon each other, but are not one in the same. Comfort and efficiency cost more and deliver more value. Just because it puts out "heat" doesn't guarantee human comfort. All one has to do is peruse the Radiant section of this sight. Lots of problems rolling by...

ME

Rich_49

" Price is only an issue in the absence of Value "
What do you think happens shortly when we can compete (somewhat) cost wise or when someone actually adds up all the ignored costs of the extra stuff that needs done to use garbage ?
Example ; bulkheads to hide ductwork , insulating the roof plane as opposed to the ceiling plane because trash will reside there , having a ready chimney ( the ducts) in every house to assist in the spread of fire , doing it right and lowering the ESP of the ductwork entails oversizing it which costs more money and nobody (hardly) does it anyway . VAV only conditions some of the air some of the time , VRF has stuff that requires a hazmat suit when handled right inside the built environment . Time to get a bit creative guys .and show the math to who matters .