Talk:Underfloor heating
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[edit] Neutral tone
"Underfloor heating is invisible from above and does not use valuable wall space with unsightly heating equipment." The bias in this sentence is a bit extreme, but reflective upon the whole article. It needs to be cleaned up, but I'm not the one to do it (I know nothing of underfloor heating, hence my reading the article) - Anon —Preceding unsigned comment added by 68.13.147.156 (talk) 04:15, 17 January 2008 (UTC)
This Article is about information but many people delete things that they believe to be spam when it is not. Link should lead to infomation not commercialism. Experts on Radiant Heat should only edit sections not random people who know nothing about it.
Thanks
This article still needs work to reduce commercialism ... 129.237.114.171 20:59, 21 November 2006 (UTC)
Speaking of neutral tone...
The whole section titled "Environmental issues of electric heating systems" says more to me about someone's prejudice against electric power than anything about underfloor heating. That "most electric underfloor heating is not considered environmentally friendly" is someone's opinion stated in passive voice. Not to mention that "environmentally friendly" is itself a vague quality to be judged. The overall efficiency of electric versus hot water systems will depend on too many factors of the given circumstance for an encyclopedia article to have a judgment. Even for a particular installation, reasonable arguments could be given favoring either one. I suggest the section be scrapped. SandyFace (talk) 05:20, 9 December 2007 (UTC)
I went ahead and took it out. It was POV vs. POV with little else, and that's not what this article is about.SandyFace (talk) 06:03, 9 December 2007 (UTC)
- Describing it as "prejudice against electric power" misses the point. Electric power is very useful for many things, but using it for heating is inherently wasteful, something that is not true of using it for other applications. This is probably not the place to explain that distinction, and apparently the deleted section didn't explain it well either. But since it's not an issue specific to underfloor heating, it doesn't really belong in this article. I think what we need is a brief mention of the issue with a link to the page that properly describes it. I'll see if I can find that page somewhere.Ccrrccrr (talk) 13:40, 9 December 2007 (UTC)
[edit] Introduction
This text needs clarification: "Underfloor heating is a form of central heating which utilizes radiant heat for indoor climate control, rather than forced air heating which relies on convection."
Reason: The percentage of heat transferred from a conditioned surface is a function of its orientation and whether it is in a heating or cooling mode. Radiant cooled floors and radiant heated ceilings transfer heat mostly by radiation but heated floors and cooled ceilings have natural convective currents which must be considered. By definition, the radiant must be more than 50% for the surface to be labeled as a radiant system, which generally occurs in most (but not all) projects.
Ref.: Short Course on the Fundamentals of Panel Heating and Cooling.(c) 2005 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. www.ashrae.org. by R.Bean, R.E.T. Associate Member ASHRAE, B.Kilkis, Ph.D. Fellow ASHRAE
Ref.:Vertically Integrated Systems in Stand-Alone Multistory Buildings (c) 2005 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. www.ashrae.org. by Robert Bean, R.E.T., Associate Member ASHRAE, Tim Doran, Member ASHRAE, Bjarne Olesen, Ph.D., Fellow ASHRAE, and Peter Simmonds, Ph.D, Fellow ASHRAE RBean 22:11, 27 July 2007 (UTC)
This text needs clarification: "Choice of floor finishing requires careful consideration, because changes of floor finish may affect performance."
Reason: Surfaces operating at the same temperature with similar emissivity will have the same radiant transfer ergo the same performance. Most floor coverings have emissivities in the 0.95 range (+/- 0.03). The difference is in the heat exchanger design to achieve like surface temperatures. For floors with lower conductivities (higher R values) there will be a need for more pipe, higher temperatures or both. Higher temperatures will reduce the efficiency of heat pumps and boilers but not the performance of the floor. 2000 ASHRAE Systems and Equipment Handbook,Chapter 6, Panel Heating and CoolingRBean (talk) 00:31, 14 May 2008 (UTC)
[edit] Comfort
This text needs clarification: " Radiant heating is arguably superior to convection methods because warm, buoyant air rises wastefully to the ceiling in convection-heated rooms, warming the upper body (often with some discomfort, particularly to the head) but leaving the lower body cooler."
Reason: Convection is a function, among other metrics, of envelope efficiency, room geometry and method of heating. A high performance building heated with convective methods has similar comfort levels for occupants as moderate to low performance building heated with radiant. RBean (talk) 00:51, 14 May 2008 (UTC)
The explanation for radiant comfort needs work. The reason why it's more comfortable is because of the radiant exchange between the occupant and the room mass. Radiant heats all surfaces cooler than the source not just the lower area. It's the raising of the mass temperature in heating(in comparison to an air based system) which reduces the delta t between the temperature of the skin and interior building surfaces. In radiant cooling, the mass temperature is lowered to encourage the body to shed its heat. At a met rate = 1.0, the human body exchanges over 50% of its sensible energy via radiation, the closer the interior surfaces temperatures to the skin temperature of the occupant the less heat loss from the body and thus the greater the perception of warmth in heating. In radiant cooling, it is the opposite.RBean 19:01, 20 July 2007 (UTC)
[edit] Merge Ondol article to UFH article
There seems to be more info re: ondol in the UFH article than in the ondol article, so maybe it should just be a section of the article and not an article of its own. —The preceding unsigned comment was added by 24.124.29.130 (talk) 10:42, 2 April 2007 (UTC).
oppose Replayamong23 11:47, 20 October 2007 (UTC)I removed edits by known banned sockpuppet. See here. --Nightshadow28 18:47, 27 October 2007 (UTC)
[edit] History
History section needs to be revised:
Text in question: "Underfloor heating was first used by the Romans." and "It is thought that the ondol system dates back to the Koguryo or Three Kingdoms (37 B.C-A.D. 668) period when excess heat from stoves were used to warm homes."
Reason: Archeological evidence and ancient documentation show the Chinese using underfloor radiant heating centuries before the Greeks and Romans.
From Transcripts of, "Secrets of Lost Empires: Roman Bath", a PBS NOVA production reads, “But the real genius of the Roman engineers was exploiting what they learned from other cultures….As they spread across the Mediterranean, coming into contact and actually conquering one land after another, they would absorb a lot of the ideas and develop some of the technologies that had been started in other lands”.
From, "The Battle Over Amaknak Bridge", Heather Pringle, Archeology May/June 2007, “To stay warm, some families built subterranean stone-walled homes with energy efficient heating systems consisting of a hearth, a stone chimney, and two subfloor channels. This system, says Knecht, Ph.D., would have burned firewood at hotter temperatures, leaving less charcoal. Moreover, the subfloor channels funneled heat or possibly steam to warm the house floors…Such subfloor heating technology was previously unknown in the North American Artic. But it resembles heated floors known as ondols that appeared in the Korean peninsula and in the Russian Far East during the same Neoglacier (3500 B.C.) period…” RBean 08:51, 2 August 2007 (UTC)
From a pending publication(out for peer review), "The History of Radiant Heating, Ancient China and Korea, to the Greeks and Romans, to the Modern World", "There is evidence of ‘baked earth’ floors in this region (Shenyang, China) dating between 5300-4800 B.C., as well as in Xi’an, China, with ‘raised surfaces treated by fire’, dating to 4800-4300, B.C.. This process of baking the earth is called zhi or zhidi and may be the process to which gave birth to the dikang.6 As note above, recently in Alaska's Aleutian Islands, an archelogical dig at Unalaska has found remains of a heated floor system charactrised by the Korean ondol with radiocarbon dating showing remains to be around 3,000 years old , about the time of the Zhou dynasty".
Short list of References: 1.The Battle Over Amaknak Bridge by Heather Pringle, Archeology, Volume 60 Number 3, (May/June 2007), featuring work of Archaeologists Rick Knecht and William Workman, both of the University of Alaska Fairbanks, and Rick Davis, Archaeologist at Bryn Mawr college in Pennsylvania 2.Chinese Architecture and Planning: Ideas, Methods, Techniques by Qinghua Guo, B.Arch. (Harbin) Ph.D. (CTH) Associate Professor of Asian Architecture and Planning, The University of Melbourne, (March, 2005) 3.Sergius Orata: Inventor of the Hypocaust? By Garrett G. Fagan, Phoenix Library, Vol. 50, No. 1. (Spring, 1996), pp. 56-66. 4.Sergius Orata Pioneer of Radiant Heating, J. Hilton Turner, The Classical Journal, Vol. 43, No. 8. (May, 1948), pp. 486-487. RBean 19:14, 20 July 2007 (UTC)
Text in Question: "Wright invented radiant floor heating, using hot water running through pipes instead of hot air through flues."
Reason: "The modern development of radiant heating started in 1907, when Arthur H. Barker, a British professor, discovered that small hot water pipes embedded in plaster or concrete formed a very efficient heating system.” Source T. Napier Adlam, Radiant heating. Second Edition, The Industrial Press, New York, 1949RBean 08:44, 2 August 2007 (UTC)
Reason: "Prof. Barker was granted Patent No. 28477 on this new system of heating, which he named Panel Warming." Hot Water Heating by F.E. Giesecke, M.E., C.E., Ph.D. 1947, pp 20.2RBean 10:10, 2 August 2007 (UTC)
[edit] Considerations
Terminology:
There is growing preference to use 'poured' vs 'wet' since a wet floor can be interpreted as a negative feature.
There is growing preference to use 'sub floor' vs 'dry' since a dry floor can be interpreted as a negative feature.
System Hydraulics:
This paragraph needs a rewrite: "Because it offers a good balance between cost and pressure drop, ⅝-inch diameter tubing is popular: ¾-inch and 1-inch tubing are relatively expensive, and ⅜-inch and ½-inch offer too much resistance, which means more energy consumption to pump the liquid through the pipe; and the ⅝-inch tubing is often the minimum size needed for effective thermosiphon."
Reason: Pipe dia. selection should first be selected on velocity; a function of flow based on design delta t and fluid/pipe characteristics. There can be equal or less energy consumption in 1/2" or 3/8" if the loops are shorter and velocity is lower by using larger delta t's so long as the velocity is kept above a nominal 1.5 fps. Often times inexperienced designers use larger diameter pipe without considering the effects on heat transfer or air and solids separation. Also it is very difficult to install larger diameter PEX in cold climates and in some "sub floor" systems. More often than not 3/8 and ½” are more than adequate for most projects. Where long loops are required, 5/8” to 1” should be considered but again ensuring that velocities do not drop below a nominal 1.5 fps.
Energy Savings:
This needs to be clarified. "Energy savings..." Reason: Energy can neither be created nor destroyed ergo it can not be saved. One can use more of the heat or power released from converting energy or reduce the use of energy but you can not save energy. See International Energy Association (IEA)LowExergy site re: "energy savings vs exergy savings".
This needs to be clarified "...up to 40% can be achieved compared to conventional heating systems if a condensing boiler is installed, but even with a standard boiler up to 15% energy savings are normal." Reason: There are research projects which suggest there is no measurable savings when comparing a hot air furnaces or hot water boilers of comparable combustion efficiencies. See PATH Partnership Research on Habitat for Humanity Houses. See also NRCan/IRC Research Project comparing radiant to hot air. Also, the more efficient the home the less importance in mechanical efficiency. I.e. in a net zero energy home there is no payback for high efficiency equipment or we can say the most efficient system is the one which never runs. With radaint cooling there can be significant power savings but this discussion is beyond the under floor heating topic.
There can be some reduced use of energy with radiant but the "how" must be specified. If the claim is " up to 40%" show the research/citation/reference...
Other comments to follow. RBean 04:24, 18 April 2007 (UTC)
[edit] Stack Effect
I don't buy the bit about reduced stack effect due to cooler walls. The stack effect is due to the cumulative weight of the air, and the pressure that weight produces at the bottom of the stack. Outside, with cold air, that pressure is more than inside, with warmer air. It's the total weight of air in the building that matters, not particularly the air against the wall. Ccrrccrr 02:07, 17 July 2007 (UTC)
Other misconceptions along the same lines include cooler air at ceiling reduces ceiling heat losses...if the space is conditioned with radiant floors the ceiling mass will be heated via radiation regardless of air temperature.RBean 19:24, 20 July 2007 (UTC)
[edit] Architectural Drawing
Hello,
The architectural drawing of the HVAC system is very difficult to read, is there any chance that this could be replaced by something that is easire to undestand? The JPEG format makes it quite difficult to discern the text. (edit: Also there appears to be a mouse cursor in the image!) User A1 11:50, 5 August 2007 (UTC)
Reply: Ideally there are about 8 sectional drawings for typical floor assemblies. Shown (with cursor) is a print screen of a small portion of a full scaled 36" x 48" home illustration.
Is there a chance for something different? Sure...it's just the time to put it together.
With permission from moderator Hu12, (http://en.wikipedia.org/wiki/User:Hu12) I could provide a link to a page showing what you are asking…
Conversely, if anyone has ‘generic illustrations’ they would like to contribute...in the meantime, greater details and methods can be obtained free of charge through various organizations and industry manuals…you’ll just have to dig for them.RBean 21:10, 7 August 2007 (UTC)
[edit] efficiency of electric--paragraph removed from article
I just deleted this paragraph from the environmental considerations of electric section.
"However, there are a number of systems available in the United States and worldwide that are considered energy efficient, due to the ability to significantly lower thermostat settings, ability to control heating operation through zone heating (only heating occupied rooms), thermostatic control, and low electricity usage. Average energy saved can be up to 40% on these systems, dependent upon proper use."
"that are considered energy efficient" is not meaningful or helpful. Lowering thermostat settings is valid and has been addressed elsewhere in the article. The zone heating advantage is not specific to underfloor--other electric heat options have the same advantage. Same for thermostatic control. "low energy usage" is just a meaningless assertion.
Finally, the 40% savings needs a citation, and a reference point (40% savings compared to what? Compared to heating the room by opening the electric oven door?) Ccrrccrr 01:03, 22 October 2007 (UTC)
[edit] Infiltration and stack effect
I just removed this confused section of the paragraph on infiltration.
- Infiltration may also be slightly reduced relative to other types of hydronic or electric heating systems because with underfloor heating, the air is only warmed slightly above the temperature of the thermostat setting, so the temperature differential at the outside wall is less, thereby reducing air infiltration due to the stack effect. This is because air infiltration and exfiltration increase as the difference between inside and outside temperature [AT] becomes larger, and so when heated air from a furnace or baseboard heater flows against relatively cold exterior walls, the increased temperature differential results in a stack effect that draws cold air into the house through any cracks [citation needed].
