Anatomy Of A Radiant Heating System. Part 1: The Hypocaust

May 09, 2010

Hello and welcome to FloorHeat Help, the blog devoted to radiant heating systems.

In previous installments, we touched briefly upon the history of radiant heating and talked about how hydronic systems are actually very similar to the human circulatory system.  Beginning with this and continuing for the next several installments, we'll a take a little deeper look at the history of radiant heating systems.  Along the way, we'll also take a look at the anatomy of a radiant heating system and how the various components have evolved.  We'll conclude the series with a discussion of what constitutes Radiant Warmth The Right Way.

Very often, a look at the past helps us to appreciate the present.  For example, consider the automobile.  Although what we drive today shares some similarities with the Model T, there are vast technological differences.  The same is true of modern  radiant heating systems and what came before.

The idea of radiant heating isn't new.  In fact, the Romans had a system called the "hypocaust" over 2,000  years ago.  Hypocaust means "heat from below," and the system was used for both space heating and hot water production. Buildings that incorporated the hypocaust system were constructed of masonary and had a type of crawl space under the floor. There was a firebox at one end of this crawl space and a series of small chimneys that ran through the walls to the roof.  The heated exhaust gas from the firebox would draft into the crawl space and up the chimneys, thereby warming the building's floors and walls.  In Roman bathhouses, a shallow pool, called the tepidarium, was recessed into the floor.  The heated exhaust gas from the hypocaust would circulate around the floor and walls of the tepidarium, thereby warming the water.  The following diagram shows the basics of a hypocaust system.  There's also a nice video clip on the hypocaust at http://www.youtube.com/watch?v=q-32UWMCrtE

(CLICK ON IMAGE TO ENLARGE)

All indications are that the hypocaust worked fairly well; however, the system had a few drawbacks.  First, it took a long time and massive amounts of fuel to heat a building, not to mention the tepidarium.  The Romans likely didn't see this as big problem, because trees were plentiful and slave labor was used to tend the fire. Second, there was no effective way to regulate temperatures, and a building's walls and floors could become very hot -- whereas modern radiant systems are designed for bare feet, sandals were likely the rule in buildings heated by a hypocaust.  Third, there was a potential for deadly carbon monoxide to leak into the occupied space through cracks in the walls and floors.  Realistically, though, in large, drafty buildings like a bathhouse, carbon monoxide poisoning probably wasn't a very significant threat. Still, despite these drawbacks, the hypocaust was an improvement over freestanding fireplaces in that it distributed heat more evenly throughout a building and could maintain a pool of warm bath water.  In the 12th Century, Muslim engineers in Syria developed an improved version of the hypocaust whereby heat was transmitted through underfloor ducts, rather than a crawl space, which streamlined the flow of exhaust gas from the fire.  The Spanish gloria system, which came into use in the early Middle Ages, further improved upon the hypocaust by locating the firebox outside and added shutters that regulated airflow to the firebox and provided some control over heat output. By having some control over the rate of combustion, people could use hay, rather than wood, for fuel.  Moreover, locating the firebox away from the building produced two other advantages.  While the hypocaust drew its combustion air from within the building being heated, the gloria system used outdoor air.  With no fire drawing inside air, cold drafts within buildings were reduced and there was no danger of filling the building with smoke in the event of a blocked vent. As with the Muslim system, warm exhaust gas from the firebox was transmitted through under floor ducts and vented to the outside via a vertical flue, or chimney.  In the 13th Century, the Cistercian monks at the Royal Monastery of Our Lady of the Water Wheel   developed one of the first hydronic radiant heating systems when they diverted water from the Erbo River to primitive wood-fired boilers and then circulated the heated water throughout the monastery complex. Yes, despite the name, the Royal Monastery of Our Lady of the Water Wheel is a real place that you can read about by going to http://en.wikipedia.org/wiki/Real_Monasterio_de_Nuestra_Senora_de_Rueda

Although a modern radiant heating system is a far cry from the hypocaust, the two share a common architecture comprised of three essential elements: (1) each requires a heat source; (2) both need at least one heat emitter; and (3) they require a means of transmitting heat from the heat source to the heat emitter(s). In the hypocaust system, these roles were filled respectively by the firebox; the building's floor and walls; and the crawl space under the floor.  In a modern system, there's a wide variety of heat sources available, including but not limited to solar collectors, geothermal units, combination water heaters, and high efficiency gas and electric boilers.  Regardless of the heat source, to work correctly it needs a heat emitter, like FloorHeat's EasyFloor System, and an effective means of transmitting heat to the heat emitter(s), like a FloorHeat EasyPanel.  For more information on FloorHeat products and services, please visit our website http:/www.floorheatcompany.com or watch our videos "The EasyFloor System" and "Radiant Warmth The Right Way" on You Tube at  http://www.youtube.com/user/FloorHeat2010

At about the same time the Romans were developing the hypocaust, the Koreans were developing a similar system called guun-dol, or ondol, which means "heated stone."  The ondol system was actually used in many parts of the Korean Peninsula until the 1960's and played a major role in the modern resurgence of radiant heat.  More on that next time.

That's it for this installment of FloorHeat Help. Please don't hesitate to let me know if there's a radiant heat related topic you like us to discuss. So long for now, and stay tuned!

God Bless!

Jim Szalla
The FloorHeat Company
3120 Spanish Oak Dr.
Lansing, MI 48911
Ph:  517,272,4441
Toll Free:  888.265.5455
Fax:  517.708.2304
email:  jszalla@floorheatcompany.com
http://www.floorheatcompany.com/

The Heart of Your Home

May 04, 2010

Hello and welcome to FloorHeat Help, the blog devoted to radiant heating systems. 

In the previous installment, we introduced you to The FloorHeat Company and gave you a brief introduction to radiant heat.  Properly designed and executed radiant heating systems offer a level of comfort and energy savings that forced air systems simply can't match. At The FloorHeat Company, we're dedicated to delivering  Radiant Warmth The Right Way.

So, once you're sold on the idea of radiant heat, you sit down at the computer and do some research. You type in your search terms, hit enter, and --- OMG, there's a gizillion pages of results.  With great resolve, you begin the  task of winnowing the wheat from the chaff.  However, in very short order, you find yourself more bewildered than informed.  Folks, there's a lot of good, competent dealers out there who will sell you a top notch system; however, there's also a lot of snake oil salesmen.  The dilemma faced by the consumer is how to know the difference. It's  caveat emptor at it's worse.    Naturally, we'd like to see you buy your system from The FloorHeat Company.  However, even if you don't, we'd still like to see you make a good, informed choice when purchasing a radiant heating system.  After all, bad word of mouth hurts our whole industry. Beginning with this installment of FloorHeat Help, entitled "The Heart of Your Home,"  we'll begin a somewhat in depth look at the how and why of Radiant Warmth The Right Way.

If you've ever taken a high school biology or health class, you already have a basic understanding of how a radiant heating system works.   Think about about how the human circulatory system works. As the following diagram illustrates, a radiant heating system isn't so very different.

(CLICK ON THE DIAGRAM TO ENLARGE)

In the human circulatory system, the heart pumps deoxygenated blood to the lungs via the pulmonary artery.  Reoxygenated blood then flows back to the heart via the pulmonary vein.  From there, the blood enters the aorta and is distributed to arteries and capillaries, where it gives up its oxygen.  Upon leaving the capillaries, the deoxygenated blood enters a series of veins, which merge at the vena cava.  The vena cava then carries the blood to the heart, where it's pumped to the lungs to be reoxygenated, and the cycle begins again. 

In a radiant heating system, a circulator (the heart) causes cool water to flow through the primary loop return (the pulmonary artery) to a boiler or other heat source (the lungs).  The heated water then flows through the primary loop supply to the supply manifold (the aorta) and is distributed to the  supply piping (arteries) for the heat emitters (capillaries).  As the water passes through the heat emitters (for example, a radiant floor), it gives up its heat and then enters the return piping system (veins), which carries the now cool water to the return manifold (the vena cava).  From the return manifold, the cool water flows to the primary loop return and back to the boiler to be reheated.   The heated water then leaves the boiler via the primary loop supply, and the cycle begins again.

In a nutshell, just as the human circulatory system is about oxygenating blood and distributing it to the various parts of the body, a radiant heating system is about heating water and distributing it to various the various parts of a building.

So, that's the basics.  Next time, we'll delve deeper into the anatomy of a radiant heating system by disecting the individual components and looking at how they work together to deliver Radiant Warmth The Right Way.

That's it for this installment of FloorHeat Help.  Please don't hesitate to let me know if there's a radiant heat related topic you like us to discuss. So long for now, and stay tuned!

God Bless,

Jim Szalla
The FloorHeat Company
3120 Spanish Oak Drive
Lansing, MI 48911
Ph:  517.272.4441
Toll Free:  888-265-5455
Fax:   517.708-2304
jszalla@floorheatcompany.com

http://www.floorheatcompany.com/

HELLO & WELCOME

May 3, 2010

Hello and welcome to the inagural post of FloorHeat Help, the blog devoted to radiant heating systems. My name is Jim Szalla, and I work for The FloorHeat Company. I invite you to take a few minutes to view our informational video The EasyFloor System at

http://www.youtube.com/user/FloorHeat2010

and visit our website

http://www.floorheatcompany.com/

to learn about our products and services.

Founded in 2003, FloorHeat manufactures and distributes radiant floor heating systems. Each FloorHeat system is custom designed for the specific building and is 30% -40% more efficient than forced air. Our EasyFloor System is one of the top rated radiant heat systems for sound absorption, which makes it the ultimate heating system for multi-level homes, offices, and other commercial buildings. It's not unreasonable for you to think that my touting the virtues of radiant heat is biased -- and you'd be correct. For your gratification and my credibility, I strongly urge you to read what the United States Department of Energy has to say about radiant heating systems by going to:

http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12590

Floor heating isn't a new idea. The ancient Romans and Koreans had rudimentary systems, respectively called the "hypocaust" and "ondol" thousands of years ago. In the early 1940's, famed architect Frank Lloyd Wright designed a precursor of the modern radiant system for his home Taliesin West in Arizona. Over the years, though, radiant heating systems lost ground to less expensive forced air systems -- yes, raidant heating systems are more expensive to install than forced air systems, but they deliver unsurpassed comfort and energy savings. Today, with ever rising energy costs, radiant heating systems are making a comeback.

Because of the cost factor, many people try to cut corners when choosing a radiant system. This is a bad idea! While a properly designed and executed radiant heating system is a joy, a poorly designed and executed system can be a bane. Remember that this is a system you're going to live with for a long time. Do yourself a favor and do it right.

From time to time, I'll be posting tips on things to consider when choosing a radiant system and letting you know about new and exciting products from a variety of manufacturers that will make your system even more efficient. I'll also be happy to answer reader questions submitted via email.

As I close out this first installment of FloorHeat Help, I'd like to extend my gratitude to a few people who helped to form my appreciation for and understanding of radiant heating systems. I've had the distinct pleasure of working with some of them. Others I know only from their books and contributions to trade publications. John Gross, Chuck Tate, Dave Hilliard, Jerry Simons, Charlie Krupka, Rod Rhor, Dan Holohan & John Siegenthaler, this blog is dedicated to each of you.

So, that's it for this installment. Please don't hesitate to let me know if there's a radiant heat related topic you like us to discuss. So long for now, and stay tuned!

God Bless,

Jim Szalla
The FloorHeat Company
3120 Spanish Oak Dr.
Lansing, MI 48911
Phone: 517.272.4441
Toll Free: 888-265-5455
FAX: 517.708-2304
jszalla@floorheatcompany.com

http://www.floorheatcompany.com/