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Old 08-28-14, 02:25 PM   #1
AC_Hacker
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Default Report Back from Heatspring Webinar...

I posted a link previously about a free webinar at Heatspring dot com.

There were so many outrageous technical failures of the webinar that I could easily fill this entire post with the disappointing details...

But the reason I was interested was that John Siegenthaler was the featured speaker at the event, and the topic was "Low Temperature Heat Emitter Options in Hydronic Systems", which is a keen interest of mine.

John Siegenthaler is the most well respected authority on hydronic heating and cooling in the US, but certainly not in the world... the US is lagging behind Europe in general, and Germany in particular.

My interest in this event was that Siegenthaler's influence pretty much sets the upper boundary of expectations for the hydronics industry in the US, and I wanted to see what that upper boundary was, and low temperature heating and high temperature cooling are at the cutting edge.

So, the webinar was about 50 minutes long, and it consisted of Mr. Siegenthaler talking while a series of 12 slides were being displayed.

I don't know that I have the right to share with you the series of slides from the presentation.

But...

I did find on the Internet, a series of slides that were used by Siegenthaler for a presentation in Diluth, MN titled, "Hydronic Heating for Low Energy Houses" that was 167 slides long, and when I searched through it, I discovered that beginning with slide #31, and continuing to slide #58, it was virtually identical to the slides from the Heatsprings Webinar.

So, the only thing lacking is the audio, which I just happen to have recorded. But even after editing, saving as mono, and using the lowest bitrate in the compression that would still sound audible, I came up with a file that is about 7.21Mb, too big for attaching. If anybody has a brainstorm for that problem, I have the sound file.

My overall impression, aside from the fact that it was a straight-across re-hash of a previous presentation, was that Sieganthaler definitely has his physics and engineering fully together.

From the perspective of information that would be usable to our DIY community, I'd say that Sieganthaler's audience is the US installer and architectural market, and that he doesn't really want to get his hands dirty with people like us, who really do want to get our hands dirty... and why should he, there's no money in it for him.

So if a body of information that is pertinent to sound approaches and best practices for the DIY world, is ever to be found, we will have to DIY that too.

All of which makes websites like EcoRenovator, and BuildItSolar, and others that are similarly good, very valuable real estate. It should also make belligerent, irrelevant postings a serious concern to us all.


As a last note, I was able to get one question answered, the question was:

Quote:

If a primary design goal for an ultra-low temp heating system was to design a system which would satisfy heat requirements, while using feed temps as low as possible, what would be the general design principles that one would look for?

For instance, it seems to me that a ceiling-emitter system would face a higher temperature due to stratification, which would result in the need for greater delta-T to drive heat into the room. So this might be seen as a less desirable configuration, given the design goal.

I'm sure that there are other practices also, that do not favor an ultra-low temperature solution. I am seeking the approaches that would most favor the lowest-temperature feeds.

I am asking this because I live in Western Oregon, where there is an abundance of solar energy, but there is almost always a cloud layer between the sun and earth. Solar thermal collectors, particularly evacuated tube collectors can supply heat, but the heat is definitely low-exergy, but this low-exergy heat is available in vast abundance.

So, Mr Siegenthaler, I am asking you, based on your enormous wealth of experience, what would be the general avenues of approach that you would take in designing an ultra-low radiant system?

This endeavor could be considered 'cutting edge'...

To which he responded:


Quote:
A ceiling that is heated over its entire area would yield the lowest supply water temperature. a radiant ceiling, wall or floor in a very well insulated building envelope would only need to be a few degrees above room air temperature to keep up with the load. Supply water temperatures in the range of 73 to perhaps 80 F would work. The general concept is to use as much radiant panel surface as possible in combination with the lowest possible load. I would avoid forced air delivery or natural convection at such low water temperatures.
His answer brings up some vital points:
  • the lowest possible load.
  • as much radiant panel surface as possible

"the lowest possible load" - This gets us right back to the ideas of
  • infiltration reduction first priority
  • insulation maximizing nest priority

Some of us are learning that standard building practices will not yield a high performance building, and that upgrading will definitely improve the situation, but will never get as far as a house that employs superior energy reduction in it's design, beginning at the surface upon which the foundation is to be poured.

And "as much radiant panel surface as possible" opens up an idea that has not been explored very much in this forum, of radiant [interior] walls, hopefully in combination with radiant floors (and ceilings).

Siegenthaler is definitely advocating the idea of using radiant ceiling cooling, which would need constant electronic monitoring for dewpoint, which is constantly changing. (Germany has been using this idea for at least the last ten years)


I'm not so sure that I agree that a heated ceiling would be better than a heated floor, areas of each being equal... but then he has the 'creds' and I do not.

Best,

-AC

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Old 08-28-14, 04:29 PM   #2
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What I got from that statement of his, was that ANY radiant panel is a good radiant panel but from what I have read of his writings over the years indicates that he still favours floor over ceiling for heat and ceiling over floor for cooling. This is a logical thought. You framed the question in terms of ceiling radiant for heat (rather than ceiling being better than floor) so I think he just continued on with that point.

Was the original point about ceiling radiant?
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Old 08-28-14, 07:39 PM   #3
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Quote:
Originally Posted by Mikesolar View Post
What I got from that statement of his, was that ANY radiant panel is a good radiant panel but from what I have read of his writings over the years indicates that he still favours floor over ceiling for heat and ceiling over floor for cooling. This is a logical thought. You framed the question in terms of ceiling radiant for heat (rather than ceiling being better than floor) so I think he just continued on with that point.
It's unfortunate that the audio recording of his entire presentation is not available for you to hear. I think you would be surprised.

> Was the original point about ceiling radiant?

I'm not completely certain what you mean by 'original point'?

Please clarify.

-AC
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Old 08-28-14, 09:30 PM   #4
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You said:

"For instance, it seems to me that a ceiling-emitter system would face a higher temperature due to stratification, which would result in the need for greater delta-T to drive heat into the room. So this might be seen as a less desirable configuration, given the design goal."

Therefore I thought that your question had something to do with some previous topic. Perhaps you were just using it as a way to illustrate your question and he responded to that alone.
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Old 08-28-14, 10:42 PM   #5
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Quote:
Originally Posted by Mikesolar View Post
You said:

"For instance, it seems to me that a ceiling-emitter system would face a higher temperature due to stratification, which would result in the need for greater delta-T to drive heat into the room. So this might be seen as a less desirable configuration, given the design goal."

Therefore I thought that your question had something to do with some previous topic. Perhaps you were just using it as a way to illustrate your question and he responded to that alone.
You know, I just discovered something...

The title of the Heatspring Webinar was, "Low Temperature Heat Emitter Options"

The title of the Diluth presentation I linked to was, "Low Mass Hydronic Emitters"

They were both the same talks... maybe the guy is just skating by.

Did you actually go through the slides that I linked to? I think that if you looked at the slides (beginning with slide 31 or 32) you'll see that floors were not the deluxe topic.

I was surprised that he didn't spend a great amount of time talking about the design of a high-performance floor. That was what I was expecting to encounter, and that is why I signed up for the webinar.

He did talk a bit about high-mass floors (like concrete & gypcrete), but he very quickly switched to the problems of high-mass floors when the heating demand for a house changes a lot. Then he went on to high-performance radiators (all European & low mass), and how radiant walls & ceilings avoid the decor problems of radiant floors (thick rugs, etc).

Near the end, he did show an example of a concrete floor, and what to avoid if you want to go with lower-feed temps (tubes in the center of the slab, good insulation under, minimize edge contact with cold foundation, etc).

Again, I wish I could post the audio, and you could step through the slides. A lot was in the audio.

As an aside, I do have to say that the discussion setup, in terms of the software, etc. that we have here at EcoRenovator, is so far superior to what they had at this Heatspring place, that it is like leaving a Mercedes, and climbing into a Yugo... we got it good here.

But, there was one person's follow-up after the presentation, that raised the question (as I did later) about temperature stratification, and delta-T and inefficiency, that could result from a ceiling heating setup. And JS really didn't pay it that much attention... pretty much said it works fine.

That was part of the reason that I inserted that issue into my question, to make sure that I understood. I mean, I have, on several occasions, measured the temperatures in various rooms in my house, and I can clearly see that temperature stratification happens, and that a higher feed temp should be required to drive heat into the room, if the surface is warmer... it's physics.

So there it was, and if somebody comes up with a way, the audio could be yours to hear.

* * *

I am beginning to think that he does get 'sponsored' by various manufacturers of hydronics products. If this is true, it could strongly shape what he says. I mean somebody did mention Warmboard, and he seemed to be only slightly aware of it.. he knew it was covered with .032" aluminum, used 1/2" PEX that was 12" on center... that's it. But the expensive European low mass radiators, got a detailed description, with cut-away Thermal Image photos, etc.


-AC
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Old 08-29-14, 06:51 AM   #6
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Nope, haven't had time to look through the slides but I will in the next day or so. I have been doing floor heat for 25+ years along with solar and other technologies and at the time I started, the ONLY info came from Wirsbo and from REHAU (and to a lesser degree HeatLink). I still have those old binders with the design criteria which I took to heart and other than for radiant cooling, the ideas have not changed.

But we in North America are always trying to re-invent or re-discover something and make it our own. It is logical to some degree because the Europeans don't build with wood structured floors the way we do and weh have to put up with nutty owners or architects trying to get 60btu/ft2 from a floor system. In Europe, this would just not happen because architects must have a heating background as well.

I have always tried to build to the designs that come from over there because I have seen that everything new and more efficient in the heating world is European and has been since I started.

Their rules of thumb are mass, mass and mass, tighter spacing for tubing and lower temps. Period. They do ceiling stuff and wall stuff but 99% is floor and there must be a reason.

There is a diagram which you have probably seen showing the temp gradients with floor heat, ceiling heat, convectors and forced air. It was around 30 years ago and is still quite valid.

I think Siggy is trying to be brand neutral and focus on fundamentals which to me haven't changed in decades so I don't go for the webinars that rehash these things. OTOH, if there was one on the Swedish bikini team building a slab on grade, very high insulation, slab heated foundation, I would probably watch, haha.
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Old 08-29-14, 12:41 PM   #7
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Quote:
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Their rules of thumb are mass, mass and mass, tighter spacing for tubing and lower temps...
As I mentioned, this presentation was about low-mass and low-temp options.

As far as I can tell, not having your wealth of experience, the high mass solutions work best for conditions where it gets cold and stays cold, with more gradual variations in heat load.

As you surely know, with low-mass emitters, the buffer tank becomes the thermal mass, and when temps change rapidly, the heating system is able to adjust to those changes.

My interest is more in ultra high efficiency (fossil fuel is not part of the picture), which would call for ultra low feed temps, so heat load reduction (massive insulation) and maximizing radiant area seem to be the answer to this. Low mass or high mass makes no difference to me personally.

There are issues with optimum flow rate and distribution optimization that I have not come to grips with yet.

BTW, I just asked him why he did give significant mention to already existing low mass high efficiency floor options in his presentation... I'll share that with you when the answer comes in.

-AC
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Old 08-29-14, 05:24 PM   #8
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Mikesolar,

OK, the webanar is now officially over.

We had Tuesday, Wednesday, Thursday and Friday to post questions.

The discussion area of the Heatspring website is really lame, but to the best of my ability to see what was going on, only 6 of the 55 people there asked any questions, one of them asked two questions, I asked three.

So this was my third question:

Quote:
I noticed that at this presentation, and your Duluth presentation, both of which addressed low mass, low feed temp solutions, you seemed to give preference for wall and ceiling radiant, and also low mass high performance free-standing emitters.

It is curious that low-mass, low feed temp floor solutions such as Warmboard, Roth Panel, RauPanel, etc. had nary a mention (I'm not connected in any way with these products).

Is your thinking shifting away from floor emitters in applications that demand ultra high efficiency?
Today was open for questions, no other question was asked, I got my question in early.

Seemed like a reasonable, respectful question...

He did not respond.


-AC
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Old 08-29-14, 07:26 PM   #9
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Quote:
Originally Posted by AC_Hacker View Post
As I mentioned, this presentation was about low-mass and low-temp options.

As far as I can tell, not having your wealth of experience, the high mass solutions work best for conditions where it gets cold and stays cold, with more gradual variations in heat load.

As you surely know, with low-mass emitters, the buffer tank becomes the thermal mass, and when temps change rapidly, the heating system is able to adjust to those changes.

My interest is more in ultra high efficiency (fossil fuel is not part of the picture), which would call for ultra low feed temps, so heat load reduction (massive insulation) and maximizing radiant area seem to be the answer to this. Low mass or high mass makes no difference to me personally.

There are issues with optimum flow rate and distribution optimization that I have not come to grips with yet.

BTW, I just asked him why he did give significant mention to already existing low mass high efficiency floor options in his presentation... I'll share that with you when the answer comes in.

-AC
Oddly enough, although I like the high mass methods more, I'm not against the low mass technologies. I think they have their place with our building methods but I do think low mass users lose some of the benefits of high mass systems (which I believe are greater than the benefits of low mass systems). I have put low mass systems into places where there is a lot of solar gain like some office buildings and moved the heat generated over to the rest of the building that is in the shade.

We all know (those who have lived in a radiant house) that the radiant floor is comfortable throughout a wide range of floor surface temps (unlike scorched air, which, when it is off, you know it's off). This is easier to achieve with a high mass floor over a low mass floor which will respond more like a steel rad than a 10 ton block of concrete. The floor will only give off the heat at the rate needed and since we are seeing (at least where we live) an increasing number of blackout situations and having the built up heat in a 6" or thicker slab is very welcome.
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Old 08-29-14, 07:28 PM   #10
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Mikesolar,

OK, the webanar is now officially over.

We had Tuesday, Wednesday, Thursday and Friday to post questions.

The discussion area of the Heatspring website is really lame, but to the best of my ability to see what was going on, only 6 of the 55 people there asked any questions, one of them asked two questions, I asked three.

So this was my third question:



Today was open for questions, no other question was asked, I got my question in early.

Seemed like a reasonable, respectful question...

He did not respond.


-AC
Maybe he will yet....

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