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'...
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To which he responded:
Quote:
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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 ºF 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.
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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