Radiant Cooling - again

Bob Gagnon plumbing and heating

Here is how I piped mine. Thanks, Bob Gagnon


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Metro Man

Radiant Cooling - again

Been looking for a good read for as up to date data as I can get for radiant cooling. I'm playing with a residential radiant heating/cooling project that would probably use concrete basement floors and gyp on all others. We space out tubing close to get down to the lowest delivery temps as possible. Conversely cooling should benefit by same strategy. Continuous circulation of floor w/heating and cooling will be designed into system.

System will be in arid Denver, CO so condensation should be held in check with proper controls.

The hurtle as always with selling radiant is when there is a AC demand. Some homeowner elect to use furnaces w/AC as the whole house system. Never mind the $50,000 granite counter and Italian marble.

I've done some initial reading from past posts here and out in cyber land. What I am looking for is some specific engineering or "how I did it" literature.

Some reads mention in radiant floor cooling a layered air affect. I would suspect this to be minimal due to the low delta T's from the cont. circ system?

I would appreciate hearing from anyone with more info, experience or direction.

Thanks in advance.

Metro Man

Derheatmeister

Solar Cooooling/dewpoint

Talk to easy E.. Danfoss has a control for this and did something with this! Must watch the dew point/humidity level so things do not condense and create damage or "Shrooms/ Mold Growing. He knows how to point you in the right direction.

We ( BO, Eric and ME) will be meeting on Saturday and installing a Solar Cooling software program which is a all German Program at my Place and will also be looking for a "party Haus" for the ISH in Germany... Ja.

Mark Eatherton

Contact....

Uponor/Wirsbo. They have a gentleman in their products development division, can't remember his name but it is Chinese, that has significant experience in the radiant cooling section. Ling Chow rings a dull bell...Could be Ling Shu, and then again, I could be all wet.

ME

Mark Custis

We have

a geothermanl radiant system with slab loops and an air handler. Still looking for a change over valve that is full port to switch from floor to air handler.

We have used gypcrete overpours too. Gypcrete does not like water.

My take on using the radiant floors for cooling is since a slab is high mass and slow to react one would need weather informtion better than we have to prevent condensation on the floor. The gypecrete may be faster to respond than concrete but not fast enough.

You could reverse and re-heat the floor in the event of a fast moving weather system, but that seems a large waste of energy. I would think rather large dehumidification systems would be needed to prevent condensation. What makes them work? D/X a/c and airflow.

I do not think I would mix the two, I see a skating rink in the basement covered by water erroded gypcrete from above.

Constantin

Consider the KARO system

Ceiling-based capillary tubes for heating and cooling. Supplement the KARO system with a small AC system for HRV, humidification, and dehumidification purposes and you may be all set in most non-humid climates.

I considered it, then rejected it on the basis of my installer not being familiar with it. This is the sort of project that requires more thought up front than your average manual-J (if that!) AC job. Good luck!

Bob Gagnon plumbing and heating

Radiant Cooling

Install some aluminum plates in the ceiling to lower your heating supply temperatures even more and the ceilings will give you a greater radiant cooling effect also. But most important is to have a fan coil unit to cool and move the air, and to remove humidity. I power my fan coil unit only with 56 degree well water and it works great, it has to be bigger than a standard fan coil unit, because the well water isn't as cold as refrigerant. Put some PEX under those granite countertops also, it will greatly increase the heating/cooling output. I installed radiant cooling in my house 8 years ago and it works great, radiant cooling in the summer, is as comfortable radiant heating in the winter.

Thanks, Bob Gagnon

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GMcD

Radiant cooling

If you haven't already checked out Robert Bean's Healthy Heating website (lots of radiant cooling "total comfort system" design material there), and done some Google searches for "radiant cooling" then I'm not sure what more you can gain here- there is a ton of material out there on the web-library on how to do it, how to design it, and doing the load calculations. The most important part of the system is building envelope quality (must be high) and solar gain control design. Regardless of whether a slab is doing radiant heating only, or combined radiant cooling and heating, the thermal mass reaction time must be understood - and this means that the building envelope has to be designed and built in a way that MINIMIZES fast-acting heating/cooling load changes inside the rooms. Then apply the heating/cooling system, then apply the controls. There are three legs of the human comfort stool- mean radiant temperature control, ventilation air control, and humidity control. Anything less and the stool falls down.

The suggestion by Bob Gagnon about using the ceiling is also a good idea- faster system reaction time compared to a slab system, and more exposed surface area, so the hydronics can operate at slightly lower heating temperatures and slightly higher cooling temperatures with all that surface area working for you (better system efficiency/lower energy use). Floors are always problematical- floor coverings/finishes, furniture masking, etc.

Metro Man

condensation

Bob,

What are you using for condensation controls for radiant cooling? I like the sprinkler tie-in. Any idea of what temps the exchanger cools loop to?

When system is running is the fan coil and the rad cooing on at same time?

I take it if your not using the sprinklers you are not cooling...

Any issues with the mix valve on rad. cooling loop?

Thanks to all who have contributed. I think I will sharpen my pencil and sift through all the info to see what makes sense. I would rather keep system(s) integrated. May look at what increasing wall spaces will get me for cooling. I really think by using a variable speed constant recirc system that I won't see those sudden calls for cooling loads. Would really like to keep away from fans and fan coil units if possible.

I looked at the capillary tubing for cooling and the stuff reminds me of the old solar roll. Brings back bad memories. if I did go with ceiling rad cooling probably would pick plates. One thought would be to NOT insulate between the floors as usually done with heating. Problem is how would you thermostatically control since part of cooling load is coming from above zone...... may need my friends hops and barley to answer this one.

Metro Man

Mark Eatherton

I am ALL wet...

My good friend and mentor, Robert Bean reminded me of the Uponor gent's real name.

It is Him Ly, pronounced Hymn (the n is silent) Lee

him.ly@uponor-usa.com

One sharp cookie.

Thanks for keeping me in line Robert. It's a full time job :-)

ME

ME

Bob Gagnon plumbing and heating

No condensaton controls

But I think I could put in a dew point sensor in the floor radiant, to cut out that pump, until the fan coil lowers the dew point in the house. But running them together has worked out great, no condensation problems at all. I could run the cooling without the sprinklers, I ran a separate pipe to my sump pit outside but I never use it. I need the cooling when it's hot out, and that is when you need to water more, it makes the system even more efficient. I have a 12 zone sprinkler system and give some water to my neighbors, so getting rid of it is no problem. I also water real deep for hours, I know they tell you that watering for more than an hour is a waste, but I don't believe it. I'll water deep for hours when the cooing is needed, then I don't water for the rest of the year. I worried about the thermostatic mixing valve too, but it is no problem, the temperature stays on maximum cold no mattter where you turn the dial. I haven't insulated the ceiling above the plates because I haven't had the time or money, but I think it would work even better, do you anticipate any problems? Are you doing this project at your own house? I urge you to do it, it was easier and is more comfortable than I imagined. Remember people with geothermal radiant cooling are REALLY COOL!

Thanks, Bob Gagnon

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Wayne_29

REHAU Can Also Help!

http://na.rehau.com/construction/heating...plumbing/radiant.cooling/system.overview.shtml

800-947-3428

GMcD

Condensation

I always hear this fear of condensation with radiant cooling - what temperature do you think you "need" to run the radiant cooling system and surface at? Typically 64F will provide about 19-22 btuh/SF from a ceiling surface at 64F surface temperature. A properly designed ventilation system (one of the three legs of the stool) has to be designed to dehumidify the outside air you must provide into the house/room/building, if you are in a humid climate. Yes, the dehumidification of the air can result in cooled ventilation air being provided, so then you can run the radiant cooling system a bit warmer (66-67F) to "blend" the sensible cooling from the de-humidified ventilation air with the radiant cooling to achieve the cooling load balance in the room.

If this is new construction, build it tight (Buildingscience.com) and infiltration of humid air should not be an issue. Penn State (Stan Mumma) has done some studies on how much effort you need to get visible drops of condensation on a radiant cooling panel, and it does take quite an effort! See this link: http://doas-radiant.psu.edu/papers.html and find the paper entitled: "Chilled Ceiling Condensation Control", plus there are others there along the same vein.

Bob Gagnon plumbing and heating

Solar Cooling?

Can you tell us more about that? Are they using hot water for air conditioning?

Thanks, Bob Gagnon

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Unknown

Working on one right now...

The plan at this point is to put 45-55* water to the concrete overpour and taking the slab to 66* as this seems to be the magic number I have found in my reading. According to psychometric chart 70* air at 50%RH will condense out at 53* so 66* floor should never condense. I'll be using Unico air handlers with lots of extra outlets and running on low speed to reduce velocity noise (because it's a recordig studio)and to cause the system to remove as much moisture as possible as air passes through the coil(s). Plus I am trying to minimalize the load they are picking up by limiting them to minimum gpm supply so they do act as dehumidifiers and not coolers. Basically I'm undersizing them as best as they will allow. I chose high velocity air handlers as they are supposed to be more efficient at removing moisture than conventional types. The idea is to have them run on humidistats primarily and come on if humidity exceeds 50%. Haven't yet decided whether I want to shut off the floors when the A/Hs come on. My thoughts now are to do a minimalist install in terms of controls, fire it up to see what I have and then determine the particulars as I gain data during the initial operation. There are provisions being installed that will allow me to add an injection pump for the floors if necessary, then the floors are layed out in zones but without actuators for now and the air system is also ducted in zones but again without automatic dampers for the time being. My thought is intermittent floor circs based on slab temp and continous low speed air circ with intermittent pumps to dehumidify as needed. I'm thinking the continous air will serve to even out the temp/humidity throughout the structure and zoning will not be necessary. If I'm wrong it will be fairly simple to make the additions to gain tighter control. There are areas where the floors will not be conditioned but I'm hoping the continous air will "rob" from the truly conditioned areas and "give" to the areas that are not. Again, if this proves to be a pipe dream I can add automatic zoning to the air system in order to use the air to condition the non floor areas. If all goes well, it should be up and running by the end of the month. I'll keep you all posted if anyone's interested. I'll be taking pics soon too if anyone would like to see them. The big hold up is the town ok-ing the pour in terms of satisfying handicapped accessability and their feet have been dragging on it. I'm supposed to get the go ahead Monday.

Mark Custis

MPF? What

are you heating and cooling with? Geothermal?

Did you know Unico makes chiller water modual? Use lots of sound attenuator tubing before the diffuser to lower the noise level. We have never had a noise complaint on a Unico install.

Arzel Zoning Technologies, here is Cleveland makes stuff designed to zone Unico. We have a four ton DX system that is zoned and it was so quiet we never added a bypass damper.

Unknown

I'm using,,,

the Robur air source heat pump. Reversible ammonia based chiller. Exceeds 100% heating efficiency under average conditions. The unico I'm using for both buildings is the 1218CW so it is not modular but I know what you're talking about, the 1218 is the only size that is not modular. Right now I'm not using any zone dampers at all save a couple manual types back at the unit(s)for balancing. I talked to the factory and the Long Island rep and they ok'd Aprilaire's dampers if I feel the need to use them once I get it going. With the Aprilaire you can adjust the dampers so that the off zone will remain partially open and you use the off zone to absorb the excess air instead of bypassing or dumping it. They are interested in the results. The guy says, "We like when people try new things with our systems because it helps us broaden our knowledge of what they're capable of." I'm going to use 12' of attenuator to all recording areas but limit the non recording areas to 6' as noise is not an issue. The velocity should be low enough that noise won't be a problem anyways. I'm basically going to install what I think are the minimum requirements at first and see what I have before I start adding any bells and whistles. The system will incorporate Robur, Unico, Honeywell, Tekmar, Wirsbo/Uponor, Heat-Flo (buffer tank / hydronic separator)and either Taco or Wilo so there are a lot of mfgs who have a hand in this and are all providing input as well as being interested in the results. Plus the local gas co (CT Nat Gas) is very interested in how it turns out and wants to collect data on the operation. They provided the owner with a substantial rebate, pretty much covering the difference between your average run of the mill system and all the fancy stuff, which is pretty much what sold the job. Meanwhile I'm gettin' antsy cause I want to pour and get my baby up and running.

other than the pour I'm about 80-85% completed

Here's a link to the unit:

http://www.robur.com/us/products/gahp-line/air-to-water-reversible-heat-pump-ar-rtar-series/description.html