The comment about having excess hot water and dumping it does not make any sense to me. Solar hot water systems used in this climate typically have a heat transfer fluid that transfers heat to water via a heat exchanger, so if water is not run through the exchanger b/c a need for hot water has not been triggerd then you are not producing excess hot water.

Have you ruled out using a solar system for its current typical use of supplying your house with domestic hot water? Keeping the technologies separate for your domestic hot water and your home heating, at this stage of technology, may be the best bet. The DOE estimates that you can reduce your hot water energy bills by up to 80% using solar hot water. In our climate you won't produce 100% of your hot water needs, but in the summer my research has shown that you can meet up to 90% of your needs, 60% in the winter, so there is never a waste issue. See my website www.ecobrownstone.com for an article about water heating which has a section on solar thermal systems.

A condensation boiler, by the way, is a very efficient technology (runs 96% to 97% efficient, as opposed to standard boilers that can go up to 86% efficient). They are more efficient because they have individualized compartments that "fire" separately for a given zone, so the entire boiler does not fire up if the thermostat only triggers on the parlor floor, for example. What's more, one of the "zones" can be a hot water heater so it's like having an on-demand hot water heater running on gas, and solar thermal can be tied into the hot water storage tank used from the condensation boiler to further reduce boiler burns. Condensation boilers also burn more cleanly with far less particulate matter than conventional boilers, and they are "direct venting" which means they can vent out of a side wall so you do NOT need to run a vent stack all the way up from the basement to the roof. We are in the process of writing a detailed article about heating and cooling, including condensation boilers, to be published in the next couple of weeks so check the website (www.ecobrownstone.com) if you'd like more information.

Also, the site will be chronicling in great detail the entire renovation of a 5-story brownstone at 168 Clinton St. in Brooklyn Heights which is just commencing, so you might find other useful information on the site as well (the site has gone live just recently, in connection with this project).
--Noreen

Posted by: Ecobrownstone at May 15, 2008 11:55 PM in response to Solar hot water and radiant floor heating

oops, I see you posted a clarification while I was drafting my comment, so some of my comments are moot.

Posted by: Ecobrownstone at May 16, 2008 12:01 AM in response to Solar hot water and radiant floor heating

oops, I see you posted a clarification while I was drafting my comment, so some of my comments are moot.

Posted by: Ecobrownstone at May 16, 2008 12:01 AM in response to Solar hot water and radiant floor heating

this comment was made earlier but people make systems with a "radiator" in the loop on the roof that dissipates excess heat (steam). there are systems designed this way. also, you don't have to size some kind of massive system to get *some* radiant floor heat gain, you can size it down to a reasonable amount and get some heating gain but likely not 100% or even 80% of your heat from the sun. think of it as something like a pre-heat for winter instead of covering all of the heating, this would still cut down on heating bills. also, if you're already installing a HW system on yr roof, then i don't understand why costs are going to be so much crazier by adding another collector for your heating.

and for the person who said "About as green as that hybrid car paul macartney just had flown from japan to england in a private cargo plane", you are completely wrong dude. go learn some stuff and come back to the discussion if you want to contribute.

Posted by: guest at May 16, 2008 10:03 PM in response to Solar hot water and radiant floor heating

I do hope people don't go ahead and install this system without first figuring out how to avoid having the excess hot water in Summer. Dumping excess water cold or hot down the sewers is BAD.

Water is the new oil. We can't waste it and on top of it we can't overtax the sewers with excess water dumping.

Posted by: guest at May 17, 2008 12:18 PM in response to Solar hot water and radiant floor heating

you could size the system to pre-heat your boiler water for the winter (not for domestic hot water, or only for some) and then in the fall and spring it could provide both domestic and heat, then in the summer it could provide just domestic.

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Excerpt from the Civil War News... "As he prepared for his Shenandoah Valley Campaign, Sheridan assembled the makings of what would be the largest field hospital of the Civil War. Immediately following the … Battle at Winchester, a 500-tent hospital was constructed (and in) …operation for three months as what is now referred to as an evacuation hospital. The tents featured a unique radiant floor heating system, which proved invaluable in the cold fall and early winter months of 1864."
_____________________________________________

the heating system was adopted from the frontiers during the gold rush in the 1840/50’s. The hospital site is being restored and there is a reenactment each year of the hospital in action including a demonstration of the heating system...it was the Civil Wars version of a MASH unit.

Tent Hospitals

The common pre-war United States Army practice was to requisition buildings to serve as hospitals. However, early in the war the isolation of some battle sites and unprecedented patient volume compelled the increasing use of tents. Surgeon Bernard J. D. Irwin established the first regular tent hospital after the Battle of Shiloh in April, 1862. The practice soon spread to the Army of the Potomac medical system under Surgeon Jonathan Letterman. Union commander in the Shenandoah Valley, Major General Philip Sheridan, insisted that every aspect of the developing medical system be made available to his Middle Military Division when he took command.
The standard hospital tent in use was 14 feet long and wide and 4½ feet high with flaps that allowed it to be buttoned to others to make a larger ward. Each tent could hold eight patients and normally was pitched two paces apart from others in rows called "streets." Every effort was made to make the tents as comfortable as possible. Boards were laid over sleepers for flooring and each tent was surrounded by a drainage ditch to keep the interior dry. Tents were heated with the so-called "California Plan." A pit was dug about 2½ feet deep in front of the tent from which a trench the same depth extended the length of the tent to its outside rear. There a chimney of some sort was built. The trench was covered with stones or sheet iron. The resulting system provided a crude, but comfortable form of radiant heat. Storehouses, kitchens and officers were placed in spare tents or temporary structures and shelters convenient to the hospital streets.

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A Rose by any other name

The Chinese called it a "Kang", for the Manchuria, it was known as ''Nahan", the Koreans an "Ondol", the Romans a "Hypocaust"...they were all forms of radiant heating and still used to this day.

The heating system used at the Civil war hospital was a form of ancient heat...it was referred to as the "Californian System" which may be a result of the Asian cultural and architectural influence in California during the era of building the railroads and the Gold Rush.

Sleeping like a Stone

The other night Dong Kwang was talking about the difference between sleeping areas here and in Korea. Traditionally, people sleep on the floor in Korea, he told us. And the floor is made of stone, or concrete.

But isn’t it very hard - and very cold, we enquired? No, he explained. There is a hole under the floor, with a fire in it, and hot air passes underneath the entire stone floor so that it’s very comfortable to sleep on it.

Posted by: guest at May 19, 2008 6:23 AM in response to Solar hot water and radiant floor heating

The following is from: "The Medical and Surgical History of the War of the Rebellion. (1861-65.) Part III, Volume II, Chapter XIV.--The Medical Staff and Materia Chirugica"

"The bedsteads used in the hospital tents were cots of a light frame-work of stout wood, provided with four folding legs and furnished with a jointed support near the head. The whole frame-work was covered with sacking, and throughout the war proved a most useful and satisfactory hospital cot. It was light, strong, easily transported, and was comfortable to the patient.
Various modes were employed for heating hospital tents in the field. Wood-burning stoves were largely used, their chief objection being the difficulty of transportation. The plan which was most generally in vogue, particularly in the Army of the Potomac, and which gave the utmost satisfaction, was that known as the California plan. A pit was dug about two-and-a-half feet deep outside the door of the hospital tent; from this a trench passed longitudinally through the tent, terminating outside its farther or closed extremity. At this point, a chimney was formed by barrels placed one upon the other, or by some other simple plan. The joints and crevices of this chimney were cemented with clay. The trench in the interior of the tent was roofed over with plates of sheet-iron issued for that purpose by the Quartermaster's Department. A fire was built in the pit, and the resulting heat, radiating from the sheet-iron plates, kept the interior of the tent warm and comfortable even in the coldest weather. In the western armies, in the trench in the interior of the tent, railroad iron was placed in regular layers and covered with iron plates when possible to procure them, or with stone slabs. Occasionally funnel-shaped stoves, open at the bottom, resting upon the ground, and provided with a short pipe, were used."

'HEADQUARTERS FOURTH DIVISION, ARMY OF THE OHIO,
FIELD OF SHILOH, April 12, 1862.

Medical Volume of the Medical and Surgical History of the War.

Posted by: guest at May 19, 2008 6:31 AM in response to Solar hot water and radiant floor heating