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OrNBRT
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Posts:2
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| 02/27/2008 4:24 PM |
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| My neighbor wants to look into a heated driveway... and doesn't know too much about radiant heating. I heard somewhere that with hydronic heating, the heat diminishes the further you get from the source of heat (Boiler???). I think( being the good friend that I am ;) ) that electric is definitely the way to go in this situation. My boyfriend and I have been researching for her for the past month or so...We are really leaning on the Nexans Cables, and think that she will agree. Not to be matter of fact, but I (mistakingly) put in my driveway without doing the research, and am regretting it with every winter!! I mean, 30 Year Warranty??? Who can argue with that? Has anyone had any experience with these electric cables? Any input would be much appreciated! |
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warmsmeallup
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| 02/27/2008 6:01 PM |
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Your information about hydronic radiant in a driveway is correct. An electric radiant system will only cost when it is being asked to run by an automatic sensor. There is also no maintenance required. There are many differences and there are sites you can view that will help to define them.
There are many things to consider when designing a snow melt system: How much area you "need" to cover, what is the power supply to cover it, what is the medium it will be inserted into etc...
The "nexan" wire is a line voltage system. Tuff Cable is a low voltage system. That means that one of them feeds actual line voltage through the element and the other uses a transformer to convert the line voltage to low voltage into the element. The two biggest differences in them is the cost and repair... or should i say the ability to repair. Line voltage systems cost less because there is no transformer or computer controller that the low voltage requires. Many manufacturers won't let you repair the line voltage element (if you can find the break in the first place)without voiding the warranty. The low voltage is easily repaired by a qualified installer maintaining the warranty.
Check the prices for both as well as the power requirements to run them to be sure you can use either one with the voltage your friend has to run it.
More questions...just ask! |
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Comfort Radiant Heating |
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OrNBRT
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| 02/28/2008 11:30 AM |
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| Thanks for the very helpful info!... I heard that transormers can get WAYYY expensive- and I think she wants to avoid putting out too much money. (Atleast, I would!) Hopefully line voltage is where we wanna be? I believe, if you have a good concrete guy (again, more research) that you shouldn't have to worry about anything being damaged. Isn't this all embedded anyway? Putting out the extra money upfront for a transformer seems rediculous to me. But what do I know??? Another reason I was looking at the Nexans cable is because its pretty thick. Seems durable. Has anyone used this cable before and have any advise or pointers? |
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warmsmeallup
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| 02/28/2008 4:01 PM |
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OrNBRT:
I have no preference as to which you use. This is just what you've asked for, personal experience. In your friend's application, line voltage may be the best element to use. They both have their pro's and con's but, speaking technically, you'd be doing your friend a disservice only looking at upfront costs. The size of the element has no bearing at all when the earth moves. But hey, the earth doesn't move anywhere but in (under) California! :)
Good luck in your decision. |
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Comfort Radiant Heating |
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HandyHammer
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Posts:33
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| 02/29/2008 7:30 PM |
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I have installed all the snow melting systems above and can also speak from first-hand experience. I have also followed up with my customers and have found that ELECTRIC IS THE WAY TO GO! As a general contractor I have researched all the snow removal systems and have settled with working with the guys at Warmzone. I have installed Nexans as well and think it is a great quality heating system. What I don't like about the Nexans and tough cable is the fact that they are wire systems that have a beginning and end to them. This translates into a real mess trying to install several wires that all start and finish at the same place. Warmzone now sells me the Danfoss GX snow melt cable that has a single termination for each cable. So I can easily and safely install a driveway in a single day. The Danfoss GX system can be purchased in a pre-spaced mat or just a single cable.
Their warranty not only covers the $20 splice repair kit like Nexans and Tough Cable but covers up to 5 times the cost of the heating system to put towards other expenses that may arise. To date I have never seen one need repair. Again another benefit to electric. A good installer will mitigate any external damage to the cable. The Tough Cable system has a series of HEAVY transformers and I only installed one to determine that they were expensive, less durable and put out less heat than the others. They guys at Warmzone.com seem to have it together and have a ton of experience with heating driveways using electric heating systems. |
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warmsmeallup
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| 03/01/2008 9:06 AM |
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While the warranty coverage from Danfoss is a plus, when do you ever need it? I have never used/seen a defective element and I'm sure you won't either. Their installation manual causes you to prevent it, as do all the manufacturers manuals. Really read the warranty from Danfoss. IF you have a break, the kit can be purchased to repair it but you (your client) looses the "30 year" warranty if you do. Their "right way" requires a damaged element be replaced..in entirety. That's not the case with low voltage. With Tuff Cable, you can find and repair the element within 1 square foot of the break with a simple butt splice and some heat shrink and it maintains the 25 year non-prorated warranty.
Like you, I've researched them all too. I use Danfoss where it fits the application and I use low voltage too, where it fits. You mentioned that the low voltage system creates less heat. Low voltage creates ANY heat psf you choose, via element spacing, because it doesn't need to always be 50 watts psf. If the element has been retro-fitted into a pre-existing asphalt or concrete driveway (you can't do that with line voltage) then the element is closer to the surface and doesn't need to use more power to generate more heat. Why waste the energy or the clients money.
Now, install the element 3" in the ground, under pavers in a sand bed, perfect for Danfoss GX. There's little to no chance for damage or breakage. I like the ability to have/offer choices. The weight of the low voltage transformer doesn't dictate which element makes it into the right application. And, having to install a new driveway far outweighs the extra upfront costs of the low voltage system let alone the lower running costs.
Low voltage does take more design time and takes up more control wall space than line voltage. In the application where it's a problem, I don't use it. I use Danfoss or Heatwave (from Heatizon). I never leave out a discussion about the warranty with my client. I explain the warranty and the what-if's of "third party damage" or ground movement and how they can, and will affect the element and they decide which their money is better spent on. Then I design it and install it. |
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HandyHammer
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Posts:33
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| 03/01/2008 10:42 AM |
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I agree with 'much' of what the previous post says but do not believe the low voltage product is that strong (THHN Wire equivalent found at Lowe's for .20/ft) and your right the other products don't need to be repaired often or ever.
As per the 50 watts a square foot for the Warmzone product (Danfoss GX) They have never sold me one over 37 watts per square foot because 50 is overkill for most situations. I do, however, like that fact that I can get there if I need it. My spacing at 37 watts was 4 inches. The touch cable would probably need to be spaced at 2 inches which is an unreasonable installation and cost prohibitive to the consumer.
I prefer Warmzone's Danfoss GX electric snow melting product due to its super high quality contruction, decades of use in Denmark, the largest international manufacturer in the snow melting business and a warranty that puts its money where its mouth is ('if' there is ever a problem). No heavy controls 90 lbs per transformer), better heat control, more cost effective, and still a closed circuit system (unlike the tough cable and NEXANS) that has only one termination point per mat. I no longer have to puzzle together a heated driveway project making sure each and every cable started and finished at the same place. I love the Danfoss GX sold by Warmzone.com. Call them for more info. My account rep over there is Matt Carter - Complete professional.
Good luck! |
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Gordy43
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| 03/08/2008 7:46 PM |
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I think you need to look into snowmelt a little deeper. Hydronic snowmelt offers the benifit to use what ever fuel for the heat source you decide is the cheapest. With electric cable systems you are bound to electricity to power the system.
Don't know what a kilowatt costs by you but NG is cheaper where I live for the same BTUS..... for now. A well designed hydronic snowmelt takes into account the temperature drop in the loops of the system.
Gordy |
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mikeinnyc
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| 03/10/2008 12:16 PM |
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Unfortunately as the price of OIL rises to record highs!!! Hydronic will be the ONLY (viable choice) as electricity rises in parallel. You guys realize the power plants use oil or gas which ever is arbitraged as the lower BTU costs? If natural gas becomes in demand it goes higher in price so you have a catch 22. If Oil goes higher every plant starts burning natural gas causing demand for the fuel to rise.
As with any hydronic system you can maybe use solar hot water/glycol solution as they become more and more viable as the Arab world f%^$ us with Oil.
If you can stay away from the grid dependence. You must be smart now so that if price go higher you will survive.
Facts:
1 Kilowatt Hour = 3,412 Btu
it takes 41.03 Kwhs to make 1 gallon of Fuel #2 oil (140,000)
thus you can conclude electricity cost with tax to you door step is NYC rate .23 cent per kWh times 41.03 or $9.44 dollars per electric to be at parity with one gallon of fuel oil.
In conclusion, to get the same energy as one gallon of oil 140,000 btus you need to pay in nyc $9.44 dollars per gallon to be at parity with heating oil. And remember NYC fu$% everybody with greed and its only going higher!
What are you paying for cost per KWH with tax and deliver charges , misc charges and all fees unheard of total per kWh?
at 3.50 per US gallon of heating oil todays price
equals .085 cents to be at parity!
Thus, if you can get your electricity for less than 8.5 cents per kWh (includes all fees!!!!!) then you will beat oil. Forget standby,efficiency rating of aflue yes i know it less but either way electric is limited to the grid or high cost solar photovoltaics panels.
With Hydronics you have a future of adding Solar Hot Water as a supplement to your heating source with electricity your screwed big time and limited to the grids monopoly prices of kWh costs.
Yes, I understand some applications electric is feasible but in the future...... and think future it may become obsolete. |
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MIKE IN NYC |
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warmsmeallup
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| 03/10/2008 8:58 PM |
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Mikeinnyc:
These stats only have meaning when both systems are running for same duration of time to do the same job. Doesn't a hydronics snow melting system need to keep the tank of water/glycol hot and partially circulating 24/7 from November to March waiting for it to snow. Can this cost be calculated?
I have some questions that I don't know the answer to (since I'm not a plumber) but have to ask to learn:
- With a hydronics snow melting system, what temp does the water flow out and back at?
- Is the returning heated water basically considered a complete waste of energy used since the fuel (or electricity) used to heat it was never fully utilized?
- Since electric is only on when it's actually snowing and all (ok, give it 99%) of the electricty it draws is actually heating the area to be melted, is that considered ( close to ) 100% efficient?
P.S. The price of oil is a speculation based on our dependance and use, not their greed. It's no different than the price of corn (apples, in New York) in bad growing season. So, we could say that we are actually f**ing ourselves.
LOOKING FORWARD TO JANUARY 21, 2009 ~ |
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NRT.Rob
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Posts:413
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| 03/10/2008 9:34 PM |
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People don't install snowmelt because it's economical to run. Frankly if economics are a concern, hire a plow. I don't know much about electrical snowmelt, but for periodic-use things like snowmelt I would not rule it out even if electrical is more expensive to run, because the initial cost of hydronic snowmelt (typically a dedicated boiler, big pipe, lots of glycol) sure isn't cheap and involves some maintenance (glycol check, boiler maintenance, pumps, etc). I'm not sure what it is for electric either, but I doubt they are similar in price. Warms, do you know a typical cost for a good size driveway? For hydronic, with a boiler, it's probably $7k to $10k for most systems of any appreciable size.
note that while the same things are true for heating, operating costs are much, much, much larger for a full time heating system and then the fuel flexibility of hydronic is of significant enough benefit to *generally* outmatch fixed-source electrical mat/cable systems, IMHO.
Frankly, I don't like snowmelt of any kind if energy usage is of any concern. A tank of gas plows a lot of snow. Doesn't melt that much though.
For hydronic snowmelt:
-Water temps vary with installation method and when you measure the temp. Starting from cold, the temps may be out at 40 and back at 20 or even lower. At "cruise", you typically design for a 25 or 30 degree drop and supply temp might go as high as 140.
-Return water just picks up more heat and goes back out.. nothing is wasted there until you turn the system off, and that's a tiny amount of waste.
-Most hydronic systems are not kept warm when not in use (only the highest priority snowmelts need that kind of response time, like ambulance ramps, where you can't wait for snow to fall to start heating up the mass). They start from cold.
-I would NEVER call electric 100% efficient. Every kwH that makes it to the unit is used at 100% efficiency, that's great, but transmission losses are something like 50%, and never mind the original generation efficiency! Of course, to be fair about that you would also have to take into account drilling, refining and travel expenditures for other fuels. Gets tricky, real fast. But personally I find the 100% efficiency claims of electric to be technically "correct" as far as a bill is concerned, but a bit misleading in the long term. Supposedly all that would be properly reflected in the cost of the fuel. Sadly, I don't regard that as true for any fuel or energy storage/transmission method we're using mass market today...
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-=Northeast Radiant Technology=-
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warmsmeallup
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| 03/11/2008 7:31 AM |
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Hey Rob:
Give me a "good size" dim as well as the medium it's in and I can tell to the penny...give me a cost/kVA also and I'll tell how much it will cost per running hour as well. Keep in mind, this will be for the low voltage system. I don't install amny line voltage. Too many possible negative issues down the line.
If you don't keep the water hot, how long is response time? Can't snow build enough to bridge if you don't get it the ground up within the hour or so? |
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NRT.Rob
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| 03/11/2008 9:34 AM |
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| response time is highly variable, depends on the mass of your emitter, output of your heat source, density of your pipe, temperature of your water. |
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-=Northeast Radiant Technology=-
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ICFfam
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| 03/19/2008 8:12 PM |
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| WOW...that is a NICE picture. It was a really, really good idea to use brick, too. Not only does it look good, but you can obviously get to any breaks later. What's the substrate? My electrical cost during the winter is $0.03103/kwh. Can you tell me what the operating cost/hour would be to run my setup all electric for 1000 sq ft? |
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warmsmeallup
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| 03/19/2008 8:30 PM |
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| The substrate is a 6" compressed crusher (no insulation) and the 1" of sand. The elements are set at 4" spacing in the 1" of sand just below the pavers. A 1000sf system of the same design would cost $4.99 per running hour @ .03103/kwh. If it snows for 10 hours, the system would be on for 15 hours and cost about $75.00 to run. The extra 5 hours is to allow the remaining moisture to evaporate to prevent it from refreezing. |
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BadgerBoilerMN
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| 03/20/2008 11:37 AM |
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NOT SO FAST
I design and install both electric AND hydronic snow melting/heating systems most of which are employed as safety devices first and items of convenience second.
Electric and Hydronic systems do "work" in exactly the same way. They heat the driveway/sidewalk above the freezing point. NO, hydronic systems do not HAVE to circulate or stay ON or use any fuel while not melting snow. This is true of any snow melting system.
There are simply no differences in the performance of properly engineered snow melting systems whether they are hydronic or electric based. Operating costs are calculated by snow load and system performance or "Class" and of course the cost of the fuel being used. Here in Minnesota the typical snow melting system cost $.25 to $.50 per square foot per season to operate depending on the heat source and operating or control system.
Those who circulate disinformation only hurt the industry and themselves.
One should first look at the work being done. There are systems that "idle" or keep the slab near the freezing point for the entire snow season and are called up to working temperature only when temperature and moisture dictate. These systems are generally designed for emergency room drives and store fronts etc. There function is for safety ensuring an ice-free walking or driving area. When a snow or moisture/temperature sensor "sees" water at or near the freezing point, the systems going from idle to heating mode raising the slab temperature to say 42F.
Of course design, installation, maintenance and operating costs must be taken into consideration. Most system do not idle or maintain a minimum slab temperature, they are simply turned off like your car until you turn them on. Many systems both commercial and residential are controlled by an embedded snow sensor and microprocessors that control everything from the surface temperature of the driveway to the outdoor temperatures in which the system will run e.g. if the outside air temperature falls below 15F the system will shut down.
These control systems are used by both electric and hydronic designers.
The heat source for smaller systems e.g. sidewalks, are not as critical, as the load will be small and the operating cost modest regardless of fuel cost. This is generally where electric cable make the most sense, electricity almost always costing more than other fuel sources for reasons previously stated. On larger systems hydronic snow melting is more commonly used. The reason for this is simple math; fossil fuels generally cost less than refined electricity. There are exceptions of course but they are anomalies.
So start with the size of your project. Ask your local fuel provider for the cost of energy per BTU. Calculate the estimated snow and/or freezing rain in your area. Material and installation specification is the last thing to be considered.
So consider this.
Reliability in the short term (20 years) is no longer an issue regardless of heat source. High voltage cable should last 20 years if properly installed. PEX tubing will last indefinitely.
Electricity will generally always cost more than fossil fuels simply because the vast majority of it is created by burning one to make the other and further noting the "extreme" waste in transmission. Hardly a "Green" alternative. Many systems use waste energy, solar, condensing boilers and other earth friendly fuels. Of course most of these earth friendly fuels exclude the use of electric cable. For this reason the majority of my large snow melting systems incorporate PEX tubing.
The advantage of PEX tubing in a snow melting system is pretty straightforward. Your heat source is no longer restricted. You may still use an electric boiler and later change your mind if electricity goes up or down! The size of the project is generally unlimited and duel fuel sources are relatively easy to design and install.
As for maintenance, the more you drive the more maintenance your car will require. After all it is doing work! Maintenance is simply one more item factored into the performance, cost, return on investment equation. Like so many business decisions you have to do the math to get the right answer for your particular situation.
Finally, there is a legitimate question about how "Green" snow melting is. The answer is not simple. If one uses waste energy the cost is a moot point. Snowplows, the trucks that drive them and the considerable fuel it takes to manufacture the whole rig is anything but green. In the end, snow melting is simply Man seeking to control his immediate environment for his personal safety and convenience.
MA
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MA
www.badgerboilerservice.com |
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NRT.Rob
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| 03/22/2008 9:35 AM |
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Nice post MA. 99% is spot on. Naturally, my post will ignore all of that ;)
I will say only in response to the green statement, that if someone buys a truck ONLY to plow snow, your argument there holds water. That is rarely the case, however, so really only a portion of the truck's manufacturing cost could be applied to the plowing of X driveway. You also have to take into account the manufacture of your boiler, pipe, etc. on the other side. the math gets pretty complicated pretty quick, for sure.
Luckily, we CAN simplify it a bit:
There is *nothing* green about snowmelt, dumping precious energy into a cold slab, outdoors, is pretty well the least energy conscious thing you can do short of getting a six nozzle 12 GPM shower assembly (which gets used every day). For snow removal, green starts AND ends with shoveling. From there, it moves to plowing, or perhaps snowmelt IF your energy source is renewable or waste heat which, needless to say, is rarely the case in residential work. If you've got green energy, somehow, and you have excess of it with nothing else for it to do in the middle of winter, somehow... well hell, melt away, as long as the capital investment works for you!
That of course does not mean everyone or everything MUST be green. But snowmelt is pretty frickin' "anti-green" in the vast majority of residential situations. It a paver protection device more than anything else. Occasionally, a retirement insurance plan against icy steps. But you could pay an awful lot of neighborhood kids or trucks to plow for what it costs to install and operate a snowmelt system, and be much greener doing it.
the situations you are talking about are primarily commercial/industrial and while that might make sense, no one on this site is dealing with systems like that. There is enough greenwashing going on these days... let's not even pretend there is a case to be made for snowmelt, ok? |
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-=Northeast Radiant Technology=-
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BadgerBoilerMN
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| 03/22/2008 12:17 PM |
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Thank you Rob;
99% isn't bad, but you already know that we rarely disagree and then only in measure. However, you know also that energy is and exact term whereas, energy conservation is relative. If most of our electricity is generated by coal fired power plants and coal generates the most earth-warming CO2, then it follows, that IF we snowmelt, it would be better to use say...natural gas with half the CO2 output.
Then there are the very steep and narrow residential driveways for which snow plowing is all but impossibe. If one were just to retrofit one of these from say the 1977 and used energy saving snowmelt controls and a condensing boiler to cut the snowmelting fuel consumption by half....wouldn't that be GREEN?
There is evolution and revolution... I will choose the former until no choices remain.
Very faithfully yours,
MA |
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MA
www.badgerboilerservice.com |
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PanelCrafters
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| 03/22/2008 1:27 PM |
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Posted By NRT.Rob on 03/22/2008 9:35 AM
There is *nothing* green about snowmelt, dumping precious energy into a cold slab, outdoors, is pretty well the least energy conscious thing you can do short of getting a six nozzle 12 GPM shower assembly (which gets used every day). For snow removal, green starts AND ends with shoveling.
Hmmm. Maybe we could take a different approach. An approach that would(might) work in most of the US. Sorry Badger, Northern MN would be an exception. Think geothermal(kind of). What if you were to pump ground temperature water through the slab. Would 45° water/glycol be warm enough to do the job(albeit slowly)? After installation, your only cost would be electricity for the circulator(and solar might be able to provide that!).
Ok, it's 20° outside, and it starts to snow. You fire up the 'ol Taco. It's simply pumping a fluid through your underground pipes and then through the slab. Would that do the job? |
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....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
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NRT.Rob
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| 03/22/2008 1:38 PM |
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that's a pretty cool idea jc. erm... no pun intended ;).
You'd probably be best served with constant circ in that case.. response time would be forever, plus a day, with 45 degree water otherwise.
Be an expensive experiment though what with ground loops and all.. |
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-=Northeast Radiant Technology=-
NRTradiant.com |
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