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Originally Posted by SkyHeating

I am confused, are we somehow bidding on the same project? I don't think I am bidding on anything quite like this with two generals and I have not been asked for radiant cooling, just as I mentioned below cooling seperate from the floor.

From googling it looks like you own Custom Plus heating in redmond, we don't do any projects that side of the cascades unless your coming to my territory lol.

You are correct Sky all the way around. Our only connection is geographical right now. Which makes you my closest geographical competion that I see frequently on this site . Sorry for any confusion.

LMAO Mike DON"T get us going on engineeers/architects. I just went to an underfloor yesterday print pic and measurements were 2 different animals. Framer built U/F to measurements, put a 6"x8" beam right though the middle of my base can, pic had it behind base can. whoops! lol

Don't ya hate it when a "knowledgeable" engineer messes up what could be a good system. This may be a topic for another thread...ranting about poorly trained engineers, but I often have to work around engineers that just pick a piece of equipment out of a book and spec it. No integration and no thought about the big picture. Same as architects that draw in flush beams then say "no bulkheads for ducts", but that is another rant too.

Originally Posted by Tempted

From what I understand carpet is no problem as long as you don't hit the dew point keeping RH low.

I was just told they are now wanting to rebid the job as I was the hvac contractor for the final the 2 generals thus eliminating competitve bids.

I have mega hours into this already dealing with engineers, "which are no longer involved due to flawed design, I pointed out" now lots of my research info is going to be relayed to my competitors. #$%^(*&^). I didn't give it all up and my closest competitor here is my bud, Right Sky? lol

I am confused, are we somehow bidding on the same project? I don't think I am bidding on anything quite like this with two generals and I have not been asked for radiant cooling, just as I mentioned below cooling seperate from the floor.

From googling it looks like you own Custom Plus heating in redmond, we don't do any projects that side of the cascades unless your coming to my territory lol.

I lost it.

General "A" should of gotten the job Way better General. General "B" way low bid it and is now rebidding the whole thing trying to make it work. I won't cut corners so he is "going a different direction" he said.

General "A" is still in contact with the architect and they are watching Gen "B". So who knows?

Thanks for sharing, Tempted. Hope things work out for you on that job.

Originally Posted by Nuclrchiller

What about the effects on the flooring? I would think the use of carpet would be ruled out entirely, right?

From what I understand carpet is no problem as long as you don't hit the dew point keeping RH low.

I was just told they are now wanting to rebid the job as I was the hvac contractor for the final the 2 generals thus eliminating competitve bids.

I have mega hours into this already dealing with engineers, "which are no longer involved due to flawed design, I pointed out" now lots of my research info is going to be relayed to my competitors. #$%^(*&^). I didn't give it all up and my closest competitor here is my bud, Right Sky? lol

I am certainly curious how this will turn out, please keep us updated as the project moves forward and post pictures/videos of what you end up doing.

What about the effects on the flooring? I would think the use of carpet would be ruled out entirely, right?

Thanks Mike,Travis and Chiller.

I will keep that tube spacing in mind Mike...

I have the same concern Travis with condesation and have read and suggested using an A/H off the the HP for humidity removal an air tempering. The engineers "from Portland" don't seem to feel that it's an issue and therfore the owners are saying no forced air. I haven't talked with them since we were awarded the job though, and we are on hold right now from H/O family issues. I will definitely plead the case and get it all down in writing either way.

Chiller it is a small niche right now, but is growing. Where it stops, how long it takes who knows. I remember a house my parents built when I was a kid in the 60's in Cali with radiant, using galvi pipe. Then radiant all but dissapeared here in residentual until a better cost effective material evolved "pex". It may not be in our time it takes hold but it will be us that determines why or why not.

I would also be concerned about what happens to the flooring due to different rates of expansion between the subfloor and whatever is on top- hardwood, laminate, tile,... I think radiant infloor cooling would have to an extremely small niche. I expect to never see it myself- on the job or off.

Originally Posted by Tempted

Hi Travis, So your not actually doing radiant cooling, your just adding cooling to radiant infloor, right?

Thats correct, I have not heard of a good way for Radiant Cooling that I would feel comfortable putting in a home. There is the condensation issue with slab cooling and its very hard to remove naturally rising heat out of the floor. There is also the issue of changing over your water storage from heating to cooling and I find that in our climate this could be very inefficient without two tanks and additional controls at which point it was cheaper and more effective to go with a ducted(off the geothermal) or ductless cooling solution.

If there is a way to do it I am certainly open to learning. But in a climate such as yours and mine that requires the possiblity of heating and night and cooling during the day it can potentially be very costly to switch back and forth daily.

One thing I would look at is the tube spacing. Just as a 6" spacing will use a lower heating water temp than an 8" spacing, the 6" spacing will have a higher water temp needed for cooling.

Remember that the same rules about having a low enough output temp to reduce humidity don't apply in floor cooling. You may have to address it in another way for humidity removal but a lot of energy can be saved by keeping the tube spacing tight and keeping the water temp as high as possible for the conditions.

I know in Europe they are often using 4" spacing for heating with heat pumps just to get the approach temps as low as possible.

Also, inverter type heat pumps have a lot less value when you are using it to primarily heat/cool a slab vs a traditional air heating/cooling. There are no typical issues with cold air blowing during defrost for example.

Originally Posted by SkyHeating

We have been quoting both Mitsubishi ductless units with ceiling cassettes(for the asthetics) or putting in a ducted system with something like a Synergy 3D WaterFurnace all in one unit with two stages of ducted heating/cooling and radiant infloor heating.

Your not to far away from me, we have two radiant geo projects going on right now that are adding cooling. One is ducted cooling, the other is 8 ductless wall ports.

Hi Travis, So your not actually doing radiant cooling, your just adding cooling to radiant infloor, right?

We have been quoting both Mitsubishi ductless units with ceiling cassettes(for the asthetics) or putting in a ducted system with something like a Synergy 3D WaterFurnace all in one unit with two stages of ducted heating/cooling and radiant infloor heating.

Your not to far away from me, we have two radiant geo projects going on right now that are adding cooling. One is ducted cooling, the other is 8 ductless wall ports.

Thanks Mike. I use Rehau also. They are going to help out on the tubing design.

I use REHAU tubing almost exclusively for my floor heating so here is a link to their radiant cooling site.

http://www.rehau.com/cms/servlet/seg...diant_Cooling/

From what I have gleaned so far in researching it and without getting indepth with formulas.
The humidity control is the ongoing concern. So far the use of aqua a/h's to lower the RH is the method of choice in residentual apps. With testing they have found that use of a regular humidity control mounted at stat hieght works well as tests show no significant difference in humidity near the floor.
The combination of the the 2 systems, radiant and air has the lowest operating cost and better performance.
While most sites contain the same information, with a few relating to having experience installing. And the few with experience aren't giving out any relavant info.
I found 1 site that did testing and the results of the tests. It's from 2003 in Korea but good info with detail.

http://www.ibpsa.org/proceedings/BS2...3_0729_736.pdf

I've only been involved in a couple of radiant cooling jobs, one was a warehouse for grains and they had De-humidification by some desiccant wheels (I wasn't involved in that part). I put the tubing, sensors and other boiler equip in. I really don't know how well it worked but i do know they didn't want a lot of airflow.

While I see the benefit of sharing the came set of loops. Cooling in not radiant. Cooling is best achieved through air movement since it's percieved by evaporation. Therefore air movement nd humidity levels have a greater effect than actual temeperature. Radaint heat is effective because we ca be effectively warmed with indirect infrared energy like a hot dog on rollers in a glass case.

It seems like it would be more efficient to use an air handler and get some air movement and moisture removal.

Besides, even in summer, who wants a cold floor. Heck, I could almost see using the radiant loop for dehumidification to heat the floors a little, which would increase sensible load for longer run times. Similar ot hot gas reheat, but putting heat in hte floor rather than tempering the air.

Cooling is tricky but doable. Some of the European companies (and maybe Tekmar) have controls that will measure RH, floor surface and air temps and mix the water temp to keep the surface just below air temp but not enough to cause condensation. As said above, you still have to de-humidify.