Post by perfumefactory on Dec 30, 2015 19:04:56 GMT -6
Most professionals call them plates, I call them fins. I'm a homeowner with plenty of copper soldering experience, 5 decades of electronics, and know tools. When I bought my first home about 12 years ago in Princeton, I learned after the papers were signed and bank emptied, the house had no insulation at all. The $500 home inspector missed this. It is a 1950's "Modern" slab, in a beautiful rural spot; my neighbor used to be George Washington...a little before me. It has exquisite construction, but some aspects I just couldn't figure out, how the sideboard heating seemed to be not quite at home...crossing, for example, what was clearly a kitchen back door, now a large window.
My plumbing skills could take care of any homeowner routines, but nothing further. Middle of the first NJ winter both the boiler & the hot water tank failed totally under too many below zero days...with a 1 year old child. Russian wife it didn't really bother! The cost of replacing both [HVAC, not wife & child] were painful, not to mention running at around $350-400 per winter month for gas. To make an already too long story short, after about 5 months of intensive web research -- back then there wasn't much information -- I began a six month installation of a solar hydronic & electrical, radiant floor system on my own. Since I didn't know theory, I put in many extra valves, temp and pressure gauges. It's amazing how a pipe will not tell you what it is doing, without the monitoring. I used a exquisite double-coiled German 80 gallon tank and a Munchkin boiler. I went room by room, demolishing, insulating, and a proprietary floor system I evolved with blue board for insulation and pex spacing, and 1/4" concrete backer board on top to retain heat and spread out the cycles. It worked automatically and perfectly for the remaining ten years I lived there. The total utility costs were lowered by about 85%. it was heavy on automated electronics long before the stuff that is around now, most of it German.
I have two questions here. In the case study "The Rigors of Mountain Hydronics", it is stated that they like the piping here because it flattens slightly, unlike pex. Back when I started my home project, I researched this question carefully, not for the expense, which is trivial, rather that my major in college was physics. I found diverse professional opinion, all unsubstantiated, until I came across a university study on the exact subject, the heat transfer efficiency of all known types of radiant floor heating...sorry, I no longer have the link. It clearly showed a dramatic difference in the heat transfer, very little by stapled tube when compared to using the fins. Flattening the tube is a minute surface area difference! I had thermistors on several of my room zones, what actually went in and what came out each room, so I could see the heat distribution was extremely efficient as long as the approximate 200 foot max pex length in a zone was not exceeded. I placed the fins closer together along exterior walls. The study showed there's miniscule transfer without the fins! What am I missing on this technique, or does it remain voodoo...closer, more dense piping than the 7 inch standard spread?
Second, the government radiant sites say 40% of radiant concrete slab heating is lost through the bottom. This is typical of all the 1950's system put in, which ruined the name of hydronic heating for decades; they all failed. In the case study photos here no bottom insulation is shown; is this not a practice with snowmelt? Wouldn't it be ideally done with a melt system, say 3-5 inches of blueboard first? And what are the driveway surface load considerations, if the piping had a masonry skim to protect the pipe from loading, could a crushed rock surface be used? In NJ any asphalt or concrete covering has zoning, drainage limitations.
Thank you. And by the way, a master plumber was over the my place for a septic problem, I showed him six, close-spaced, copper stubs, sticking up in the dark back of the former utility closet, which I had transferred to a bigger location that wasn't in the middle of the house...that's what is so great about pex, the utter flexibility of placement. I couldn't figure out these pipes, thinking an old, long gone bathroom. He immediate reply: "1950's hydronic!" I was about half-done with approximately a total 8000 square feet, the large living room & kitchen remaining. The 3" added floor thickness was a major issue in the kitchen. I was over to Costco within the hour, bought a compressor, soldered in a fitting and pressure gauge, saw the needle climbing. Hit ~80 lbs, shut it off, saw no change, went to get a coke....10 pounds on return. Googled for a couple of weeks, no cure short of running radioactive stuff through to locate the leaks, like a heart stress test, with an exotic portable detection system...then digging up the slab for each probable leak. Moreover, from my air tests, they had five zones, but only ONE return line for all. They should have known the chemistry back then, the reaction of the caustic concrete with either copper or the probably the solder. This failure, which must have been a homeowner disaster, with masonry walls & no wall internal space, even for insulation, plumbing runs were almost impossible. I sued the ceiling, which with pex was not too bad, even with 75' runs. This explained the weird sideboard heating, which severely altered the ambience of the home...and without insulation, was not up to the job. If only I had known!
Thank you!
My plumbing skills could take care of any homeowner routines, but nothing further. Middle of the first NJ winter both the boiler & the hot water tank failed totally under too many below zero days...with a 1 year old child. Russian wife it didn't really bother! The cost of replacing both [HVAC, not wife & child] were painful, not to mention running at around $350-400 per winter month for gas. To make an already too long story short, after about 5 months of intensive web research -- back then there wasn't much information -- I began a six month installation of a solar hydronic & electrical, radiant floor system on my own. Since I didn't know theory, I put in many extra valves, temp and pressure gauges. It's amazing how a pipe will not tell you what it is doing, without the monitoring. I used a exquisite double-coiled German 80 gallon tank and a Munchkin boiler. I went room by room, demolishing, insulating, and a proprietary floor system I evolved with blue board for insulation and pex spacing, and 1/4" concrete backer board on top to retain heat and spread out the cycles. It worked automatically and perfectly for the remaining ten years I lived there. The total utility costs were lowered by about 85%. it was heavy on automated electronics long before the stuff that is around now, most of it German.
I have two questions here. In the case study "The Rigors of Mountain Hydronics", it is stated that they like the piping here because it flattens slightly, unlike pex. Back when I started my home project, I researched this question carefully, not for the expense, which is trivial, rather that my major in college was physics. I found diverse professional opinion, all unsubstantiated, until I came across a university study on the exact subject, the heat transfer efficiency of all known types of radiant floor heating...sorry, I no longer have the link. It clearly showed a dramatic difference in the heat transfer, very little by stapled tube when compared to using the fins. Flattening the tube is a minute surface area difference! I had thermistors on several of my room zones, what actually went in and what came out each room, so I could see the heat distribution was extremely efficient as long as the approximate 200 foot max pex length in a zone was not exceeded. I placed the fins closer together along exterior walls. The study showed there's miniscule transfer without the fins! What am I missing on this technique, or does it remain voodoo...closer, more dense piping than the 7 inch standard spread?
Second, the government radiant sites say 40% of radiant concrete slab heating is lost through the bottom. This is typical of all the 1950's system put in, which ruined the name of hydronic heating for decades; they all failed. In the case study photos here no bottom insulation is shown; is this not a practice with snowmelt? Wouldn't it be ideally done with a melt system, say 3-5 inches of blueboard first? And what are the driveway surface load considerations, if the piping had a masonry skim to protect the pipe from loading, could a crushed rock surface be used? In NJ any asphalt or concrete covering has zoning, drainage limitations.
Thank you. And by the way, a master plumber was over the my place for a septic problem, I showed him six, close-spaced, copper stubs, sticking up in the dark back of the former utility closet, which I had transferred to a bigger location that wasn't in the middle of the house...that's what is so great about pex, the utter flexibility of placement. I couldn't figure out these pipes, thinking an old, long gone bathroom. He immediate reply: "1950's hydronic!" I was about half-done with approximately a total 8000 square feet, the large living room & kitchen remaining. The 3" added floor thickness was a major issue in the kitchen. I was over to Costco within the hour, bought a compressor, soldered in a fitting and pressure gauge, saw the needle climbing. Hit ~80 lbs, shut it off, saw no change, went to get a coke....10 pounds on return. Googled for a couple of weeks, no cure short of running radioactive stuff through to locate the leaks, like a heart stress test, with an exotic portable detection system...then digging up the slab for each probable leak. Moreover, from my air tests, they had five zones, but only ONE return line for all. They should have known the chemistry back then, the reaction of the caustic concrete with either copper or the probably the solder. This failure, which must have been a homeowner disaster, with masonry walls & no wall internal space, even for insulation, plumbing runs were almost impossible. I sued the ceiling, which with pex was not too bad, even with 75' runs. This explained the weird sideboard heating, which severely altered the ambience of the home...and without insulation, was not up to the job. If only I had known!
Thank you!