Talk:Underfloor heating

Neutral tone

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)[reply]

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)[reply]

Comfort

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)[reply]

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).[reply]

oppose Replayamong23 11:47, 20 October 2007 (UTC)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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)[reply]

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]

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)[reply]