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Nailing the lid on the Suspended Tube Coffin
Comments
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No
Adequate is a big word that covers more ground than the industry seems willing to discuss. It's wrong to think that the ability of a distribution system to carry a thermostat setpoint under design is necessarily "adequate".
We all agree that the "suspended tube" radiant floor is the cheapest and lowest quality radiant floor available, right?
I'm saying that it's possible to design and install a radiator system for as much or less money that is much more effective, more efficient, more reliable and of MUCH less questionable quality than this stupidly cheap radiant floor heating method. And just as "comfortable", if not more so by virtue of the enormous increase in control and effectiveness.
Comfortable, toasty, etc. are all feel good words that may relate to the human condition but in reality don't mean much. It's not necessarily radiant floors that produce that condition. It's wrong to think that condition can't be produced other ways. All those feelings all relate back to security and satisfaction (terms used by ashrae) and true security is produced efficient, effective and reliable heating systems. If you are all these thiings than you will also be "comfortable".
I especially love "toasty". It's got so much spin on it that I have a hard time keeping a straight face when I use it in sales presentations. You can put a sickening amount of spin on comfortable by finding ways to change it to "comfy", as in; "Buffy will find the warm marble floors in the master bath of your trophy home especially comfy, Mr. Rockefeller." (Buffy squirms in her chair at the mere thought of such hedonistic pleasures)
Performance is something that can be measured and expressed mathematically. Comfort or the lack of it is that can get be demonstrated in many people to experience by simply suggesting it to them. Any one who has ever seen a stage hypnotist or is close to marketing people can attest to this.
I think that there is no question that many folks with staple up radiant floors assume that they must be more "comfortable" simply because they have been told so. The significant dollar outlay helps reinforce the impression. They never know the path they didn't travel, so they really don't know if there wasn't some other alternative that might have been of much higher quality and just as "comfortable." Especially if it was promoted as such. Despite my encounters with Buffy and Malcolm, I don't sell on "comfort". If I do a good heating system of any kind it will be there. Comfort follows performance. You can measure performance.
I think that we understand each other Rob, i enjoy the discussion point and counterpoint.
Dale0 -
So what you are saying is that it's a great heating system to have in a climate and a building where it doesn't run much.
Dale0 -
Ok Ok
If your loads are minimal. However where I work it is rarely acceptable. I will not ride that fine line. We need heat here. I'm battling the notion that one still needs heat installed(Warm air. So where is the economy? If a secondary system is required when it gets cold. Or who accepts the liability when these systems don't perform? I have yet to see any major manufacturer or wholesaler stand behind their heat loss. That is criminal!0 -
They will...
They will stand behind the formula, and the math.
The person providing the dimensions, the insulation values, the infiltration quantity, and the type and QUALITY of construction would guarantee those items.
I've had to stand behind ours.
Noel
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Not all are reputable
I've had a wholesaler calculate two jobs for me in almost 22 years. One took 6 weeks to get (done by then) and the other was off by 25,000 BTUH. Sounded low so I checked it, design temp diff wrong and 60 sq ft of glass was missed. I have since been on a few jobs calculated by this wholesaler that were insufficient and NO reparations were made and ANY culpability denied.
I realize not all are the same and sincerely hope my experience is the anomoly.0 -
Assumption Reports
are a great idea. Some manufacture's heatload and design software programs provide this important report.
Have the owner or contractor sign them agreeing to the window type and area, insulation R, and floor coverings. The only tough one to "know" is workmanship, i.e. the insulation contractor and siders.
If the heat loss and design is based on tile and hardwood and you arrive to carpet and pad, pull out the signed Assumption Reports
Keep in ming there is a lot more wiggle room with transfer plates if you need to overcome some missed or changed design criteria. Keep an eye on flooring surface and underlayment temperatures when you need to boost output, however.
hot rod
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Hey Dale,
What part of the country are you located in?
Design characteristic temps are different all over the country. Just because the temperature in San Francisco doesn't get down to single digits doesn't mean that a contractor has to install a job like it was in Minnesota or Wisconsin.
Design criteria in HVAC, as well, is different in various areas of the country. Houston has incredible latent cooling loads and the same size house in Denver may be 25% of the Houston home. The system is sized and installed for the particular area. One size doesn't fit all.
Tom0 -
well Dale
Once again, it's not YOUR definition of comfortable that matters. Many people have been in homes with radiators and baseboards and decided they wanted radiant floors. Warm floors. You can have warm floors without plates. That is fact. If you need 15BTUs/sq ft, no one except the components of the radiant system and maybe the fuel bill knows whether that 15 BTUs/sq ft are being driven by conduction or under floor convective loops. If you are getting the quantifiable performance needed, then it can be considered adequate.
Whether the extra cost of going radiant over radiator panels is worth moving the source of heat from a wall to the floor is not your decision to make. It is the homeowners. That's not a quantifiable measure of comfort. That is a measure only the occupants of the building can put value on. Because it's their desire that determines what Value is.
Look, I'm almost as big of a radiant snob as you are. I just object to black and white characterizations. There are times and places for suspended tube installations. Saying there is not is simple sloganeering. And I'm enjoying this too, I always love a good debate in good faith!!
_______________________________
Northeast Radiant Technology, LLC
Robert Brown, Co-Owner
NRTradiant.com0 -
Boys, Boys, Boys !!!!
My dad used to say when a couple of us brothers would get in a heated discussion. Then he'd sit us down and referee the bout whilst we discussed (or whatever) to our hearts content.
Kind of what we need to do here......
We can see from all the above posts that some have had rotten experience with suspended tube. Some have had excellent results with many systems in and working just fine, thankyouverymuch. We have to look for the common denominator in the systems that have yielded both results........ and this should be an excellent lesson for ALL the homeowners, DIY'ers and heating guy wannabe's reading this post.
In a nutshell the lesson is this:
The success of a suspended tube system, or any hydronic system for that matter, depends entirely and completely on the skill, forethought and knowledge of the person doing the design and installation. Bill Clinton has had many satisfied customers with this type of system. Others, myself included, have seen horror stories in action brought on by the "one size fits all" mentality of nearly all the WWW tubing companies.
For a homeowner to go to one of these con arti..... I mean companies and buy a radiant "system" from someone who has never laid eyes on their home is incomprehensible to me. Maybe that's just because of the experience I've had in trying to straighten out some of these complete disasters. Just look at the poor sucker that I mentioned in an above post. And I do mean SUCKER!!! There are TOO MANY VARIABLES on any radiant heating job to just say "do it like this" and expect it to work.
Maybe it's the American, mass production way, to try and simplify a job, process or product so that anyone can do it. Even with their eyes closed if you will. Hydronic heating in general and radiant heating in particular will never be able to be reduced to the current level that forced air heating is at for example.
There are a myriad number of ways in which any radiant heating situation can be addressed. Many of them are wrong and only a few are correct. That's what I love about this trade. Each job presents its own set of challenges and circumstances. I have to figure out which is right based on the building load, the construction type, the homeowners budget, and a host of other minor factors that enter into every job.
The beauty of hydronic heating is that I have a whole menu of "pieces" to choose from. The possibilties are limited only by design considerations and budget. The wise installer will be able to match the system to the task at hand and the budget. The wise homeowner will be selective about his installer and be aware that many things can and do go dreadfully wrong if the pieces are not matched to his job.
As always, the good things in life, the things that really work, are worth the price. As always, the person who buys something that's notably less expensive but "does the same thing", usually gets screwed.
To sum this all up, there is a time and place for almost any product and method currently "out there" in radiant land. There is no blanket method that covers all the bases. To blindly just suspend this and plate that and panel the other thing is a recipe for a heating system FUBAR.
As Mark E. says "Happy Hydronicin'".0 -
Same difference
Rob, you, and the radiant market are telling the customer what constitutes comfort. You are telling your customers that radiant floors are more comfortable than a decent radiator system, (for example) but you don't know it to be true. And it's not true.
Radiant floors are not the only way to create a comfortable heating system. That's just hype and hubris that can't be supported.
I tell people that I can produce an equally comfortable, but much more efficient and effective heating system using other, more reliable and effective techniques and we all know that it's true, and if you ask them later, they would tell you that it's true. Are you saying that they are "uncomfortable", or that they would be more comfortable with a cheap and cheesy radiant floor that is so constipated that it may not even be able to produce enough heat at design? I think that they would disagree.
For what it's worth, ASHRAE does define comfort as "that indoor condition at which an occupant expresses satisfaction with the thermal enviroment." They go on to say that different individuals, depending on their health and age and degree of physical activity etc will define comfort in differert ways. Engineers actually only have to "satisfy" 80% of the occupants of a building to be considered legally "successful". It's hard to account for the other 20% or exactly how "uncomfortable" they are.
Again, I notice that no one in this thread is responding to any discussion about performance issues. All I hear are discussions revolving around the raw ability of a heating system to carry design load. THAT IS NOT WHAT I MEAN WHEN I USE THE WORD "PERFORMANCE". I think that's unsophisticated, shallow thinking. You mentioned the possibility of "higher fuel bills". Your customers may be interested in this. This is one of the real measues of performance.
Also, Rob, I doubt very much much whether many folks in this country have much experience with a high performance radiator system. One with generous radiating surface in the room, above the floor and it's thermal resistance, one moving heat by convection directly into the room air, one on full reset that drives the boiler temp down to the lowest possible temp, one that is appropriately zoned to deliver the right amount of heat where and when it's needed, one that may even use proportional TRV's ir eveb proportional zone valves rather than on/off thermostats to provide the final measure of control to regulate space temperature, to provide homeostasis. That's what we are after, homeostasis, or consistant and controllable thermal equilibrium with the lowest possible energy input. That is where "comfort" comes from. The absence of discomfort. Satisfaction with the thermal environment.
We owe it to ourselves, our customers and our environment to carefully define comfort, performance, efficiency, and effectiveness. We're the pro's, it may seem arrogant, but we really do know more about comfort and performance and efficiency than our customers do. We live and breathe this ........ stuff. {private grin} We live with and, (hopefully), learn from our mistakes and improve our methods. Our customers respect us and pay us for our expertise, experience and best advice, just as we respect and pay others for theirs.
Monitor a heating system for a couple of years and evaluate the several numerical variables that constitute performance and then talk to me about comfort. There is much more to this issue that is being ignored and is only revealed to those willing to take a much closer, objective, look. The devil, as they say, is in the details.
Dale
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Hello Tom,
I live in south, central Montana, just norh of Yellowstone Park. A real heating climate.
I understand very well your point regarding design conditions. I have been trying to address the several operational performance variables that the staple up folks are preferring to ignore or deny.
Dale0 -
Very well said !!!! ....NM
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what are you telling me?
You're telling me one of two things. Either you're telling me I've never been on a suspended tube jobsite and felt warm floors, or you're telling anyone who has and liked it that they are wrong.
I'm sorry Dale, it's not that black and white. It may not have Value to you. It does to some. and before I get pigeonholed by people as a suspended tube advocate, remember that I literally do this only 1% of our projects out of choice. But telling someone who wants a warm floor that they have to spend $4k on aluminum for a low loss area or it's just not "good enough" when I know it will be would be irresponsible of me.
_______________________________
Northeast Radiant Technology, LLC
Robert Brown, Co-Owner
NRTradiant.com0 -
Performance
Rob: I think what Dale is saying is that the "warm floor comfort" can be possible, but at much better performance (in terms of capital cost, operating cost and impact on the environment) if it is applied efficiently. Staple up systems may meet part of the overall "performance" definition, but from this design engineers' point of view, staple up systems are not very efficient from an operating cost point of view. Trying to heat up a floor with insulating barriers between the heat source and the radiant emitter is just not good engineering. Let's open up our points of view- there are a lot more ways to achieve high performance radiant heating systems than strictly floor systems. Radiant ceilings, panels, slabs, applied capillary tubes, etc.
Human comfort is made up of three major items: mean radiant temperature, air movement/convection (which includes air temperature), and humidity/perspiration. Satisfying all three of those variables creates "comfort". A radiant floor system coupled with an adequate ventilation system, with humidity control, can satisfy all of those parameters. Now, the trick is to do it efficiently, using less energy and materials, hence less pollution, hence lower operating costs, at a budget.
The right start is the building envelope. The North American HVAC industry treats HVAC systems as something that can be applied anytime, anywhere, to suit whatever building envelope design has been created. I suggest that the HVAC engineer should be much more involved in designing the building envelope performance in terms of eliminating heat losses and solar gains outside the building, using passive systems designed into the envelope. Architects and homeowners know squat about glass performance and solar gains so somebody has to help point them in the right direction. Who better than the guy who has to deal with energy guzzling HVAC systems to react to those poor building envelopes. I'd rather design simple passive HVAC systems that have low maintenance, long life and provide reduced operating costs - it has to be "whole building design approach" rather than a bunch of separate entities parachuted in to provide "reactive" solutions to what someone else has designed.0 -
in most cases
yes. in low loss areas though payback can take a loooooong time.
I completely agree with the envelope first approach and try my best to push for good windows and insulation when we can. However as we all know, this is not an ideal world, and many is the time I don't get to look at a planset until the envelope is already standing there waiting for someone to put heat into it immediately. There are many tools in the toolbox as you mention, I myself usually shoot for ceiling in areas where suspended tube might be adequate typically. But then sometimes you can't do that either (lots of post and beam/timberframe homes up here with no ability to put heat in the exposed beam/floor ceilings).
Finally, you guys keep talking comfort like it's a constant for everyone. Remember, some people just want warm floors. You can satisfy the "major parameters" however you like and that's great, but it's not a warm floor, and some people just want that warm floor, that is, they want to feel the warmth from the floor, on their feet. Would they be comfortable with other heat? quite possibly. Would they be as Happy? That is not your decision to make.
None of these situations are the norm and I do not suggest suspended tube is a great application or should be used in most jobs. It does, however, have its place. It's a small place, but it's there.
_______________________________
Northeast Radiant Technology, LLC
Robert Brown, Co-Owner
NRTradiant.com0 -
i just read this.....
i would like to say we are telling each other what we already know:).........Really like a fine heating system we should keep it to a whisper:) remember with ten different plumbers you will get (n!-00-1) different ways to get the work accomplished:)0 -
*~/:)
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Yes, Yes, Yes
You are barking up the right tree, Geoff. I think that we understand each other. When we talk about performance, we have to look at the whole thing. The entire system includes the building. HVAC pro's do, or should know more about what makes up "comfort" than most of our customers. We also know more about what is mechanically tenable and what is mechanically obtuse.
We also take responsibility and liability for the things we design and install. It may sound arrogant, but we don't do things just because people want us to. Most of our customers indulge in some form of "compulsive engineering", especially when it comes to radiant heating, solar etc. And that's cool, our job is to educate them and work out their needs and desires in reality.
But there are all kinds of things that we simply won't do. Staple up has always been one of them. Ironically, the ThermoFin was born over 15 years ago when a rancher in BigTimber MT wanted to retrofit the old farmhouse by stapling polybutylene under the floor. I threw some holy water over my shoulder and politely declined. I never imagined in my wildest dreams that it would work at all. (Big Timber MT has got to be one of the windiest places in the world.)
That was our first extrusion project, we used copper for that one and several others until we got access to pex. If you want a system that really snaps, using copper over pex in the ThermoFin can drop your operating water temperature another 10 deg. It's a LOT of work and you spend some time picking flux out of your nose afterward. Nothing like sweat soldering with your head in the joist bay. : -)
Thanks for posting Geoff.....let's hear more.
Dale0 -
Rob,
The adverse effect on the system performance, which shows up in the economic performance is not related strictly to the lost effciency of staple up used in the "low loss zone". Payback doesn't neccesarily take a long time.
The loss in performance is more related to how the higher water temperatures affect the rest of the distribution system and heat source. There is not a one to one relationship between water temperature and flue gas temperature. Raising the operating temperature by 20--60 deg has a large impact on flue gas temperature. Producing the hot water for the single, small, "low loss zone" affects the efficiency of the entire system.
Just because over heated boiler rooms are credited to the efficiency under AFUE, doesn 't mean the the credit shows up in your pocket. The reality is that heat that's not delivered, is lost in non useful ways.
Non condensing boilers can be operated at water temps as low as 120. Hydronic heating distribution systems want to be designed operate with minimum return water temperatures that are in this range most of the time. That's where the economics come from.
BTW, many folks don't realize that "payback", where the original investment value is returned, is the inverse of return on investment, ROI. Paybacks that may not look that attractive, may actually represent returns at rates that are not available to the "investor" otherwise.
Many folks don't distinguish between investment and consumption.
Buying / building a house and a heating system is / should be investment.
Dale0 -
absolutely
It's not *necessarily* a long time. But it can be and that's where doing the math is important. And it's not appropriate that every customer should feel like they absolutely must pay a much larger cost up front in order to "make money" ten years down the road, if that's what their actual performance would indicate.
Furthermore, your arguement is true, of course, it's out the window with most hybrid systems out there, and they are quite common, aren't they? Baseboard second floors happen in your neck of the woods too, right? Finally, you can get return temps in the range you are talking about in many heavily insulated homes even in my climate; as siggy says it can be a fine choice for the 15BTU/sq ft range. Especially if you are using reset controls to modulate system temperature with demand!!
You can't make a specific arguement without a specific case. My only arguement is that in general, some of those specific cases do not justify the much larger up front cost of plate systems, for a variety of reasons, and not all those reasons are quantifiable, though many are. I don't see how you can argue that that isn't true.
_______________________________
Northeast Radiant Technology, LLC
Robert Brown, Co-Owner
NRTradiant.com0 -
Sure,
We do baseboard and radiators all the time, that's what I've been arguing, but these days, with the controls we have available, it's easy to size them to work with reset as well, while the lower temp zones are tempered to their own reset curve.
Both of these devices behave quite differently than a couple of plastic pipes below the floor. While they may need higher water temps at design than we like, that doesn't happen that often and they can be reset just like radiant floors for lower outputs at lower water temps. 120 deg radiators are "quite toasty". Much of the year they can run at pretty low temps and drag the boiler and the rest of the distribution system temperature down as well.
But BB and Rads are not constipated like staple up. When you put more heat to them, you get more output. If for somoe reason a customer doesn't get enough heat, you walk up to the control and change the reset curve or the parallel shift. Building extra capacity in the distribution system gives us flexibility. Also, beats going to court.
The suspended tubes especially have to be run hard to get anything out of them at all, and they are so constipated that, as we have established in this thread, it's hard to increase their output much beyond the "10 btu/ft2" at any water temp. So their operating characteristic is to circulate constantly at fairly high water temps with virtually no temp drop across the zone. The return line comes back hot immediately, even on start up because there is no coupling to the mass of the floor. Turn the water temp up a lot and get slow, sluggish or no response.
This isn't directed heating, this is almost inadvertant, happenstance heating. Efficiency (and comfort) comes from creating just the heat you need and directing it to the right place at the right time in the right amount without losing a bunch of it along the way. With modern hot water systems, we can do that.
As far as economics go, this is the future.
Dale0 -
I'm So Sorry this caused so much grief,,,
Honestly,
In the words of our former (somewhat respectable President) ; William Jefferson Clinton--"
" I Have Never Suspended Tube with That Woman."
I would have rather seen all of you telling me how awesome my last Vitodens project was. It's the way of the world. I just can't keep pace with Heatboy:( Who can?
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Don't you ever be sorry fer bein' honest, sonny!
This stuff needs to be talked about.
Staple up does suck. Just like hot air systems with collapsed-flex-duct-hung-with-baling-wire sucks. Just like anything that stops heat flow and runs the appliance up to it's limit without dumping much of the heat sucks.
It's obvious isn't it?
Why should an adequate system be the standard? Why shouldn't a more efficient system be the standard?
Yesh, yesh.... I know what yer thinkin'... Yer thinkin' I bin drinkin' in the wee hours of the mornin'. Well, yer right. I'm fulla wild ideas. And I'm truth talkin'. There's nothin' wrong with the truth, is there? Or am I just foolin' myself? *snicker*
There ya have it.0 -
I intentionally stayed away from this thread
to see if anyone would mention copper tube stable up.
No one did.
Am I the only contractor who:
1) uses it - almost exclusively.
2) and sees the potential for 50BTU's/SF.
3) the absence of product failure with occassional 210° water temp.
4) virtually no dT accross the panel by virtue of 2-pipe reverse return design.
5) no noise.
6) highest thermal conductivity of any and all tube "forms" on the planet - including PEX/AL/PEX.
7) with Dale's plates, would be the highest output of any material known to man ever installed - at the lowest water temp conceivable.
8) no proprietary fittings, manifolds, zone controllers.
9) no spaghetti on viagra "bird's nests look" at the supply and return manifolds.
10) no "model of the year" problems with parts obsolecense and euro designed special tool crimps/connectors THAT ALWAYS LEAK BEFORE YEAR 5.
11) never have to worry about how long it laid in the sun.
12 never a concern about chafing or latent kinks.
13) 100% of the material is always O2 impermeable, not some miniscule but trace amount of permeation like ALL synthetics.
14) expansion and contraction issues non-existent (at least compared to plastic or rubber).
15) always straight - can't "droop" and fall away from the underfloor.
16) held in place by simple cc 2-hole straps
17) ask customer, "Would you prefer a plastic tube job radiant"? "Or would you prefer copper"?
18) the warranty on copper is lifetime.
19) the warranty on on plastic is ~ 20 years
20) I have some old Entran I could install at real good price. Maybe I could get it for free. Is free okay?
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copper staple-up
Verrry interesting. I remember impressive infra-red pics from hr showing apparently very good output from copper. You say you use copper two hole straps to hang it. How do you avoid expansion noises? My preference (using pex) has been to suspend the tube both to avoid noises and to maximize convection on the theory that the contact patch is so small that most of the heat must go through the convection phase: What is your opinion on this theory?
Gotta tell you I always phantasized about getting one of those 430 cube Marauders: thought I was the only one on the planet who even knew they ever existed--and you actually had one! If you welded those spider gears, you must have been taking it out to the drag strip. How did it do?
Bill0 -
I asked about that lifetime warranty.
They told me the only way I could have a lifetime warranty is if they killed me as soon as I walked out the supply house door.
So yer sayin' I can git all my money back on that pinholed copper I keep fixin'?0 -
Pappy,
Sorry your staple-up sucks---the ones we have done heat. All of the Pex with plates and Onix with no plates have done everything we have asked. Please don't tell my wife that her 2nd floor Sewing Room (with 3 outside walls and carpeted floors) that has Pex/Plates is uncomfortable, she doesn't feel any difference in it than she does with the tile/hardwood floor with Pex in the slab.
TA
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There you go Pappy
Yes, this does "need to be talked about." I think us wetheads need to learn a little about energy conservation, energy economics and how to look at the big picture.
I like the analogy of the collapsed flex duct. It's always been hard to understand how anyone could be proud of such a "system". Some of the installations that we have all seen are enough to make one gag.
The "radiant panel industry" seems to have no standards and promotes no sophistication. Anything that sells a lot of plastic pipe goes. Major manufacturers have no problem promoting the staple up - suspended tube approach. As soon as Siggy published his article they immediately came to the defense of the "method" and rationalized the bad news. Apparently, doing enough calculations will efficiently heat the house.
It puts them in the same class with and adherent to the same poor standards as our friends who promote weird oversize "partially" xlinke plastic, barb fittings, hose clamps, open loop system and of course, staple up "staple up radiant floor heating". Whatever it takes to give you those wonderful "warm" floors.
Jesus Pizza, it's a heating system, not a sex toy!
As you said, Pappy, anything that "stops heat flow and runs the appliance to it's limit sucks."
That's the operating characteristic of these systems, constant circulation at high temps with virtually no delta T across the floor because there is no heat transfer to speak of. Boiler short cycling on limit. Lots of extraneous heat loss from the distribution piping, boiler etc. No control, No response. No chance for regulation.
No one would intentionally size a real hydronic or air based heating distribution system to behave this way.
Some folks have a hard time with the truth Pappy.
Dale0 -
Conduction over convection
Bill,
The staple up systems, where the tubing has some contact area with bottom of the subfloor perform much better, move more heat per deg dt (water temp - air temp) and have much faster response. Because it can be squashed and present more contact area with the bottom side of the sub floor, the rubber hose will perform better, (btu/ft2 (dt water temp - indoor air temp) ) than the rigid tube, pex staple up system. The increased contact area makes an enomous difference.
Passive air spaces make good insulators, not good heat transfer mechanisms.
In the U Kansas study, simply pulling the rigid, 2" extruded polystrene insulation 2" away from the tubing increased the time to equilibrium or "ramp up to steady state" from 4.26 hrs for the system where the insulation pushed the tubing tight to the floor vs
10.05 hours for the system leaving the 2" air space where the tubing was allow to sag and lose contact with the subfloor.
In the same study, the Thermofin system by contrast took 3.89 hours to reach equilibrium with the insulation pressed tight (5/8" air space), and 5.04 hours to reach equilirium with the insulation pulled 2" away.
The ThermoFin system reached equilibrium at heat transfer rate of 47.6 btu/ft2 @ 140 deg f supply water.
The staple up system reached equilibrium at at rate of 22.4 btu/ft2 @ 140 deg f supply temp.
The resistance was a single layer of 3/4" plywood. Just a subfloor, no finish floor. Both systems used 1/2" nom. pex. tubing, 8" oc.
Air spaces make good insulators, if that's what you're after.
Dale0 -
Copper in ThermoFin
You're right about that Ken. As I noted elsewhere in this thread, use of copper over pex will buy you a 10+ deg drop in operating temp.
We are starting to experiment with radiant cooliing panels. We need to use copper in the aluminum extrusions because we have such a narrow temp range to work with. 40 deg f chilled water to 70 deg f air. Only 30 deg max. Using pex immediately sucks 10 deg off it. We're bonding the copper in the snap channels with a high heat transfer epoxy so there are no air spaces.
With a heating system we can go 110+ deg max dt water temp - air temp. Not that we should, but with heating we have a lot more driving force to work with.
I remember the copper ThermoFin floor heating systems we did involved picking flux out of ones nose after one was done sweat solder in the joist bay. I suppose these days the copper crimp fitting would be the way to go. I'd recommend copper in ThermoFin over pex for some systems, condensing boilers, ground source heat pumps and solar systems. These systems are all about economics. Constipating the delivery system constipates the entire investment in efficient hardware.
Dale0 -
I confess
Obviously the laws of Pickard physics prove that suspended tube can't work without voodoo help from the beyond. Our dirty little secret is that on every job we seal into the joist cavity a copy of Dan's "666 Ways of Screwing Up." Calling on that magic number gives us systems that heat up in a reasonable time, are quite controllable, transfer the heat we want, etc, etc, AND et cetera. I know come judgement day, I'll pay for this but for now my suspended tube systems work just fine--- As do my radiator systems, baseboard systems, radiant ceiling systems, and my favorite: radiant floor with tube embedded in mortar or gyp laid on top of wood sub-floor and topped off with tile or stone; whatever meets my customer's needs best.
By the way, I disagree with your disparagement of the emphasis on "comfort". The delightful thing about radiant floor heating is that you can use it to shift the conductive/convective/radiant components of thermal comfort way over on the side of radiant. This means you can have an ambience of cool air while still being quite warm. It's wonderful! Of course with tight efficient houses everything including the air reaches an equilibrium so you can't maintain that radiant advantage unless you do something wild and crazy like open the windows while cranking up the floor. Try it: it's great! Inefficient? Irrational? Poor engineering? So sue me.
Bill
0 -
You should
come to Wetstock.Retired and loving it.0 -
Bill,
We ran 'A' Gass class at Island Dragway in Hackettstown, NJ. We never understood the wheel hop phenominen while coming off the line and must have broken 10 trannies from the shock of wheel hops. By the time we put two extra beefy leaves in the rear springs to prvent the cause (rear leaf spring "wind-up") we only ran three more races before packing it in and growing up.
Prior to the spring fix, we lost every race with a blown trans. After the spring fix we won all races by 2 or more seconds! If memory serves, our best ET was something like 8.9 @ 145 MPH. The weight of the car was over 5,000 pounds. Which didn't help at all.
RE: the copper output... We used true size 1/2" two-hole straps and would put two wraps of teflon tape on the pipe where the strap would jam the tube tight to the sub-floor. If the runs were longer than 9'2", we would use 3/4" straps on 1/2" copper 'm' tube and intentionally allow it to hang down from the sub-floor that sisxteenth to prevent creaking noises.
The 9'3" number was derived by the fact that we would pre-solder all the 'U's by taking 20' ltgths of tube and cut them to two 9'2" lgths., and the 8" remainder would be the connecting remainder to allow the two lgths to be joined and would result in a pefect 8" spacing of each supply and return "trombone."
Matter of fact, the picture shown in our "Find a contractor" ad link below was one of the highest output copper radiant jobs we ever did. Note the kitchen shot and the wall of glass we had to overcopme to get the required 70° dT of the load. The load required 45 BTU's /S.F. and we got it. They had 115° surface temps along the glass wall because we did the last wall edge tubing not as a simple 8" 'U' - but did two 4" spaced double 'U's like this U¯U. We also made sure a 2-hole strap was tightly secured on the center of the ¯ part to assure as intimate a contact point as could be mustered - where the trombones ended at the glass wall.
The underside was fitted with 2" thick foil faced rigid foam, wedged in each joist bay. There was a 2" void between the foil face and the tubing. The system was frequently challenged by temps dropping below design temps by 10° a few times and never needed help. I must say, to maintain the perimeter/glass wall surface temps and the comfort inside, we saw water temps at 190° more than once. But those tiles were almost too hot to stand on for more than a minute or two - without discomfort. That WAS however, only the perimeter edge. Since no one stands with their shoulder to a glass wall or door, it was no problem either way.
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
UltraNeedy
You guys may be missing the magic elixir, of course. All you have to do is add a lot of labor, weaken the structure, and buy a space-age product to adapt these high-temp systems into maxi-thermo, largo-dynamo, plop-plop-fizz-fizz, human-orgasmo, warm floor master maintainers.
In essence, you need OmnipotentFin! No, sorry, UltraFin! Geez, to think you have wasted all this bandwidth, and have not even developed a consensus document that would solve all your problems! You slackers! [grin]
Strap on the Ultra! Hey, it has third party documentation! It has the approval of every Tom, **** and Harry who has just started out in the radiant biz! Siggy wont condemn it; as it has worth (in some areas of the country worth might be debatable, definable, or elective, dependant on the percentage of professionals currently employed). It has the shiny, shiny, metal. It is aerodynamically neutral! Easy to paint, light in weight! Can be installed by InUtero children with very little training required.
You can solder it--sort of--to copper pipe so they won't spin around and around (unless you design them to spin around and around...and around).
Birds and rodents don't like them when enclosed in joist spaces because they look like predators! They might even be sharp, razor sharp, if you add a bit more labor.
Remember, plastic tubing costs a lot of money, so designing with UltraFin or the much dreamed-about UltraAbsorbentFin (dream-patent pending), might be in your future.
Labor is really cheap, as is energy. These things are fact! Stop flip-flopping and deal with the facts! Labor and energy = cheap. Excessive plastic tubing = waste of money.
And what about high-quality extrusions? Heck, no one in their right mind would want to make money in an honorable fashion, in this day and age. Lets drop the pretenses and get down to the buck-stoppages. Heat transfer is funny and too hard for the masses to understand, let alone installers. We need to work towards a good concerted effort of selling material goods. Period. And lots of them! Let the trade-zines be our bibles.
If the world were my oyster, I would pull a random page from a random trade-zine and buy a hundred items from the advertisement that would surely be on that page. This, in the marketing world is a way of inspiring salesmen! Yeah, you bought it, you should design your systems around what you have in stock! Robo-clap. Not contagious.
Lets get back to the basics and sell a bunch of stuff from the largest corporation we can lay hands on! Are you with me!? Yeah! I thought so. [big fat self reflecting chuckle]
Note: All characters or ideas in the above are rooted in some sort of melancholy sarcasm I think. Sorry.
In all honesty, thanks for a very enlivened thread, folks. Its good to see Dale back in top form, and Ken still working his marvelous copper magic .If only Lenman were allowed! Or the unspeakable beast of the beyond--unameable .I guess there are more than one of them!
Michael Ward0 -
Sorry that you fell so threatened Bill. I suppose it must be how the dodo felt. If you want to continue thinking that air spaces make for good heat transfer between surfaces, please don't let me interrupt your fantasy.
But when you have no technical arguments, you resort to making sleazy comments. I'm sorry that you don't want to acknowledge any kind of engineering or economic definition of performance, but that doesn't mean you have to snidely scorn some very good reasoning and the investigative engineering or others.
This thread was started because John Siegenthaler, a very knowledgeable and reputable engineer, quite experienced and practiced in the trade, felt compelled to write articles in the trade press, warning contractors, designers and installers off of the staple up/suspended tube approach. Why? Because they fail.
Most of the participants in this thread, even if they want to concede some place for these methods in the industry, also have stories to tell about how it doesn't work. The method has little or no latitude, and it's efficacy almost always uncertain, despite how many silly calculations one performs. When these systems fail, they cost big money, pain, anquish, consternation, blame and loss of reputation.
All I am doing is pointing out how these systems fail even when they still manage to muster the output to meet a thermostat setpoint at design. Though you may prefer to ignore all nuance of performance and and effectiveness in your mechanical designs, many of us are want to polish distinction, especially economic, engineering and installation distinction. You can see it in the excellent tradecraft that you often see illustrated and documented among the progressive contractors on the here on the Wall.
About comfort . I can define comfort in quite specific terms with a psychrometric chart. I really don't need terms like "ambience". So when you "open the windows and crank up the floor" does it make you excited? Sounds more like a drug experience than a heating system. It must be quite "delightful" and "wonderful" that you would spend energy and money on it. Perhaps it might be synthesized in pill form for sale on street corners.
Must be California thing, like Viagra. Maybe I can explain. Here in Montana, we have this thing called Winter. In Winter, it gets cold. It snows and the wiind blows. There are times that it's just, well, it's just uncomfortable outside. We design heating systems for buildings, because, without them, the buildings get cold. Centuries of experience tells us that cold is uncomfortable and expensive. So we try to avoid it. Getting cold that is. Or spending too much money getting warm. I'm not sure that many of us knew that there was more to it than that, but then, we're not too bright.
I hope that helps.
Dale
0 -
Crazy
Good to hear from you Mike. You're crazy as a 'coon!
Here's an interesting thought experiment. Calculate the area available for heat transfer in the typical Ultra Fin, ThermoFin, and staple up / suspended tube appliation. Use, say.....25 btu/ft2.
Calculate the energy density at the tube/plate/ultrafin interface. Use all surfaces, both side so the plates/ultrafin and all of the circumferencial area of the tubing. Compare and contrast. I think you'll find the results "illuminating".
Dale0 -
R.O.F.L.M.A.O....
You crack me up Mike.... I've got tears of laughter in my eyes from laughing. Thanks, this place needed that!!
Oh Lordy...
ME
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
All I can say is...
paint 'em flat elm leaf green and the insides of the bays flat black and see what happens (seen a guy do it, swear to ...Oh wait, I quit swearin'...:-)
This "debate" will NEVER end... Rightfully so...
It's all about heat transfer, and conduction is King!!
ME
To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"0 -
Slurry Mood
Wowza, Dale! You know I can't do those kinds of calculations. But thanks for letting me envision myself at a low table, with colored sticks and wood blocks, trying to work it out! [grin]
Just tell us what you have figured out, dude! It sounds interesting. Then we can hire the high-priced spinner of marketing or the high-priced engineering guru to put you in your place! [snort-laugh-snort] Ooops...slipped back into some sort of cynical politico eavesdropper mode. Sorry. [backs into corner, thumb to mouth, fetal once again] Must learn...must learn...must learn...speak is bad. Thanks, Dale!
Thinktanked,
Michael Ward0 -
Situational Mag Fighting
Hey McGyver,
You are certainly welcome. Thanks for the laughter.
Got the latest Contractor Rag today, but haven't been able to turn to your page yet. Was waylaid by a bunch of really cool advertisements and such. Will get there soon!
Hey, they printed the same little bit about hydronic marketing in CB as they did in C! Never noticed that they were sister publications before--if memory serves!
Man, that's probably the first rule of critical thinking...look to the sources--any sources, any connections. I knew I would lose my brain one day. [g] I guess I need to simply get back to basics and read every little bit of every little thing they choose to publish.
Nope, nope, nope...and positively nope. [g]
Have fun,
Michael Ward0
This discussion has been closed.
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