Coley got me a thinking, ::) I have 3 manifolds on my OWB,only using 2 of them. The other was for a working garage,more a thinking,that never happened ::) I would like to hook up pex pipe to melt the snow off from a 6 foot by 30 foot walkway. This is next to the garage,so I know at least 4 feet out is all sand. I have small stones for a walk way,looks nice but a bother not to shovel into the rocks to remove the snow. What I do now is cover it with rubber belting and remove the snow than put the rubber belting into the garage. I don't like to leave the belting,it's slippery with snow on it. That is a bother too. I was thinking about using pex pipe and bury that into the ground. I could hook up another circulator to my spare manifold and just let it run,with no thermostat on it. Would just letting the circulator run keep the snow away? I think I would have to run some smaller lines once I get to the walk way. I would come into the walkway and out with 1 inch lines. I'm in Maine with temps that are below freezing most of the time and can get into the singles numbers for a few weeks steady. Snow fall depends,but 6-8 inches a week can happen.
It will work but, your heat load will be 250 btu's per sq ft. 45,000 btu's per hour for that walkway. The uninsulated ground under the pex tubing will become a heat sink and melt snow in a much larger area than just your walkway. It would be better to have a controlled on- off system that is used as necessary. That would require 2 circulators a plate to plate heat exchanger and anti freeze in the piping that could freeze.
Another "I was a thinking" plan goes wrong. ;D
Quote from: thecfarm on January 01, 2013, 08:22:49 AM
Another "I was a thinking" plan goes wrong. ;D
Like many plans, it can be done, but is it worth the time and money?
I would argue that it is still doable. Look at the hassle you are going through now and the difference in the right way to do it compared to what you initially thought. I see the difference as being enough antifreeze to fill the line to the walkway, a sidearm and a second pump. Do you heat your garage because if you do it becomes even easier. You could also put the sidearm in line with one of the existing pumps and simply turn the other pump on manually for the time it takes to melt the snow. Added cost from the original idea to the new is the cost of the antifreeze and the sidearm.
Meant to say that if the garage is heated I would put everything I could inside so that line loss for most of the system is not wasted.
If you were to go through the trouble of digging up the walkway to bury pex why couldn't you line the bottom and sides with 3" of foam board to keep the heat from spreading further than the walkway and use a little less heat?
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There's a commercial building east of town with heated sidewalks. It's vacant now but the now deceased builder and former owner had a large wood boiler to heat the whole place. He had a separate pump for the sidewalk loop with isolation valves in the supply and return. When the walks needed thawing he opened the valves and turned the pump on. The key to his system was anitfreeze in whole thing. It was filled with automotive antifreeze. He had connections at the air base in Oscoda that got him all the used antifreeze that was changed in Air Force vehicles :)
It certainly is a viable option for you. Insulating the area with2 to 3 " of pink or blue foam board will work. Do it once the right way and you will get years of not having to clear off the walkway. Only other thing is you will need an expansion tank for the anti freeze zone or you need to leave it open to the atmosphere, maybe a 11/4"x 10' stand pipe for expansion of the fluid. It will take 1 loop of 1/2 inch tubing spaced 6" on center to do that walkway
Cement the walkway then put up walls & a roof . save the cost of melting snow. Or waite till the first of June It will be gone. splitwood_smiley
Yes I could put down foam board,which does make since and yes the "wifes" garage can be heated. I just have to insulate it first. The heat exchanger is on the other side of the garage, but could splice into that and still keep the maniford for my "working" garage.
If you were to move the garage heat exchanger to near the walkway you would minimize the amount of antifreeze needed. The sidearm could have a small reservoir above that could also act as an expansion area and the switch for the pump would be easy to put in and convenient for use.
Sidearm exchangers are best where you are heating a tank like your hot water heater, for this project I think a plate to plate exchanger would be a better and smaller choice.
I expect a plate to plate would be a better choice but a sidearm can be homemade and with no speed expectations I think the sidearm would do the job at a modest price. If the lines under the walkway are going to be a continuous 1/2 inch pex loop then I would try a sidearm made of 3/4 and 1/2 copper. Very cheap and salvageable if it doesn't perform adequately.
Cost wise by the time you buy a heat exchanger, extra pump, expansion tank etc. and hook the extra stuff up. You could probably just fill your whole system with boiler antifreeze add one pump with isolation valves for the sidewalk circuit and be done.
You might be able to buy the anti freeze for around $65 for 5 gallons. A 50/50 mix would be how many gallons?
Maybe it wouldn't be so cost effective ;D :)
My OWB holds 155 gallons,half is about 78 gallons, divide that by 5 gallons, round that off to 15. 15-5 gallons buckets, $975. Than I think that has to be changed after so many years??? Looks like I will keep shoveling.
Probably one pail would do it if it only had to fill the sidearm, under walkway 1/2 inch pex and a small reservoir with pump attached.
Now I gotcha. :-[ That sounds much better. sorry. :-[