In ground solar powered snow melter ???

[Jeck Dl]

Hi Everyone, a newbie here :p

I have an urge to make something that will melt snow on my 360sf driveway using nothing but solar power. Any ideas on how I can accomplish this clever task? I spoke to quite few companies out there but with no luck finding a solution. I have a choice in using a concrete or asphalt on the driveway. Also I thought that I would mention that I will be using 3 panels and 15 watts per panel setup plus 1-2 12v car batteries, or more if that is suitable for the setup. Then using a converter from DC to AC will power the snow melting system?

Any takes??? I am open to all suggestions.

Thanks for you help,
Jeck :)

[Paul Bailey]

Re Snowmelt: Please be advised that snowmelt takes ALOT of BTU's (heat) .I think around 100-200 btu's Per Sq/Foot of driveway to accomplish this task depending on your local climate, until the melt is done then shut off to conserve energy. What are you going to use for controls and where are you going to get the heat From (what source)?????

[Joe Blake]

Living in Sunny West Australia, I've never been troubled by snow, but you would need a LOT of power to melt the snow. To get some idea, take a 1000 watt radiant heater and apply it to the snow. It will take a L-L-L-O-O-O-N-G time for anything appreciable to happen.

First idea that strikes me is to prevent the snow landing on your driveway in the first place. Some tent-like structure with a high, sharp peak would cause the falling snow to slide off to the side. If it were made out of a strong fabric like shade cloth, you could prod the roof from the inside without tearing the fabric to remove snow, plus any melt water would drip through the weave onto the driveway and hopefully drain away.

The second way I'd look at it would be to physically remove the snow after it's fallen. I've no first hand experience but the Wovel looks like an interesting concept.

YouTube - The Wovel - Ingenious Snow Shovel

Without knowing much (read "anything") about the design of your house, is there some way you could harvest waste heat, say from the flue of your central heating (assuming you have that), a pot of water, a few rocks to heat up, bricks etc?

If you got some "cold tolerant" water pipe, made up a reticulation system on the driveway surface, filled with concentrated brine or water/alcohol anti freeze solution and had a heat exchanger of some sort for the waste heat, the anti-freeze would still circulate under the snow and give up its heat to the snow. You'd need some way of draining the solution so as not to damage the environment, and store it for future use. By using appropriate junctions etc you could dismantle it over summer and store it away, and in the colder weather, if it does the job it can be drained, lifted up out of the way when you wish to use the driveway then put back in place later.

Another thought might be to have a raised track running across something such as cinder blocks, with a metal treadway that allows water to drip through, so when the snow DOES fall the track is either higher than the snow is deep, or the snow is not deep enough to cause difficulties. Further, the tread would give better traction than an icy surface.

If you have a strong fixed point such as a big tree or bollard, and a hand winch (a la Turfa or similar) lay pipes lengthways along the driveway and cover them with the shade cloth. When the snow has fallen, attach the winch to the reinforced edge of the shade cloth, and using the pipes as rollers, DRAG the entire packet across the driveway, removing the snow in one fell swoop - - er sweep. (This will of course only work if the winch and the holdfast point are strong enough.) If you drag the load over a larger diameter pipe, it may be possible to cause the snow to fall off as the cloth runs over the pipe. This could be set up to work in sections, rather than the entire driveway.

If you have ropes fixed to the ground on the WINCH side, running UNDER the roller pipes to the side opposite to the winch, and attached to the shade cloth, it may even be possible to gather up the rollers at the same time.

I think there are many ideas that need to be looked at, that won't require oodles of energy, except mental.

Do you have a swimming pool? There's quite a lot of heat retained in water, that can be harvested perhaps.

Joe

[Jeck Dl]

Hi All,

Thank for the quick reply...

Anyways I took everything into consideration and decided that it will be better to work with liquids than just plain electricity. I think it will be more efficient that way.

Here is my problem. I will be using 3 solar panels @ 15 watts each making the total 45 watts. The trick is can it be that 45 watts of power, then connected to 3 batteries then connected to a water 4 heaters ( this is them here (http://www.kitchencollection.com/Temp_Products.cfm?sku=01057082)), be enough to heat up 15.5 gal of water in a beer keg?

So from panels > inverter > batteries > dc/ac converter > power strip > 4 water heaters.

Will this be enough to make the water hot with 45 watts of panels?

Thanx again,

Jeck Dl

[Rob Beckers]

Hi Jeck,

Let's try a little engineering: I'm not sure where you are located, but obviously it's someplace that gets snow in winter. That means you're far enough north to get at best around 2.5 sun-hours per day (if that). That means your 45 Watt in panels will produce 2.5*45 = 112 Watt-hours of energy.

Now, nothing is perfect in this world, least of all in engineering, and there are losses. A reasonable assumption is that you'll net about 70% of that energy at the business end; to heat water. So that makes 78 Watt-hours of energy per day.

To raise 1 gram of water in temperature by 1 degree centigrade takes 4.2 Joule. A liter is 1000 grams (more or less), so that takes 4200 Joule, or 1.17 Watt-hour of energy to raise by one degree centigrade. Your 15.5 gallon is 59 liters, so raising it 1C takes 59*1.17 = 69 Watt-hours.

You have (optimistically, if the sun is shining) about 78 Watt-hours available, so that will heat your water tank by 78/69 = 1.13 degrees centigrade, or 2.03 degrees Fahrenheit per day.

In other words, this ain't gonna fly. You'd be better off using your hands to melt the snow, or pis..., eh, urinate on it. :eek:

-RoB-

[Joe Blake]

Rob's point about losses is very valid. So I thought why bother going through all the hoops of paying for PV cells, wiring, inverters etc when a simple solution involving nothing more than a paper guillotine, lots of old CDs and some PVC piping?

Make a cardboard or plywood template of a hexagon the same diameter as the discarded CD/DVD and using the guillotine, cut the CDs into a hexagon. As anybody who's ever looked at a beehive knows, the hexagon is the most efficient packing shape. Make sure you cut the CD with the transparent side down, otherwise the action of the cutter will start peeling the reflective aluminium off the CD. (If you wish to be finicky, a smear of some glue around the cut edge will seal the coating in place.)

Using the PVC pipe build a frame to hold as many CDs as you reckon you'll need. The CDs make an EXCELLENT light/heat reflector, so when you've built this reflector, turn it onto the snow. To my mind, this is the most efficient way of using the sun's heat, with very small loss. If this won't melt the snow then it's highly unlikely that a solar panel of the same surface area will generate sufficient power to do the job.

The prototype I built

http://i82.photobucket.com/albums/j245/saxeharp/general/Picture21.jpg

while not built on a PVC pipe frame, nevertheless (in summer) gave roughly 10% increase in output from this array.

http://i82.photobucket.com/albums/j245/saxeharp/trike/trike03.jpg

I'm hoping to build a larger reflector integrated into the PV array, so I can just put the array in position, get the angles right and then open out the reflector.

You might refer to this thread I created a while ago.

http://www.greenpowertalk.org/archive/index.php/t-1919.html


A more elegant solution may be to build the reflector with a focal point to concentrate the sunlight. (The "Death Ray"!!!)


Joe

[Gil Martino]

Newbie here.

I'm interested in this as well, we live in NY state, midstate.

I seem to remember something about a geothermal piping system that is below the frost line, about 4 feet down that could pump a liquid through some pipes and "retrieve" heat. Is this possible?

Gil

[Joe Blake]

Newbie here.

I'm interested in this as well, we live in NY state, midstate.

I seem to remember something about a geothermal piping system that is below the frost line, about 4 feet down that could pump a liquid through some pipes and "retrieve" heat. Is this possible?

Gil


I certainly think it's "possible", given that the soil would permit it to be done (eg it's not solid rock, as around my house). However, without knowing all the figures, I'd be pessimistic about how much of a hole one would need to dig. I'd probably put two piping systems, one on top, one underneath, so it could be used collect heat winter from the outside to warm up the house, and to collect heat and dump it in the atmosphere in summer time to cool the house.

An alternative might be to lay a couple of feet of sand inside a largish frame or an old water tank, and make a "raised garden" using a piping system. I think there many variations on this theme.

I've even seen a system which relied on old builders rubble; rocks, bricks, chunks of concrete. Anything that has a high thermal mass can be used for a "heat bank". Put this inside a "greenhouse" in an exposed location that will collect heat and store it till you need it.

One rather fanciful idea that has crossed my mind over the years is to buy a couple of pallets of house bricks and use them as a thermal bank for a decade or two, and then when the price of bricks has risen to a suitable level, sell them for a profit to someone building a house. Since the pallet loads will already have spaces in to allow for lifting and transport, maybe it would possible to create your piping system with very little effort. Just feed some garden hose through the bricks?

;)


Joe

[Gil Martino]

Hey Joe,
I did purchase a Wovel, and I like it. It's a novelty of course, but the reality is that it saves my back the strain of a shovel. I used it quite a bit over this past winter. You are pushing down, as you 'flip' the snow over the side. Now, when there is a lot of snow or it is heavy you need to push it then lift, then wheel it to its location, then flip it, then wheel it back to the lifting point...etc. It's great for us folks that want to protect our backs.

It is sooo much better for me than a typical shovel.
Thanks,
Gil

[Gil Martino]

Joe,
You bring up a great point about clearing my driveway. I've been thinking about adding some PVC piping into the blacktop to push some heat through it to melt the snow.

However, I believe that you are correct that there MUST be better ways to remove the snow that are logical that don't require power. ie. the building of the pyramids.

So, I will be heading down this path a bit over the summer. That is, designing something that will remove the snow which will not require me to shovel. I suspect something designed with ropes and pulleys would be plausible.

Ideally it would be easily set up, and done by having 1 or 2 people pull on a rope, or some kind of crank. Let's assume that anchors are not a problem, since we could drive rebar into the ground and attach climbing ropes with pulleys to them.

Gil

[Joe Blake]

Great news. Glad to help. That's why the forum exists.

Now if only we could find some way to get your excess snow over to sunny Western Australia.:bigsmile:

Joe

[Brian McGowan]

Melting snow with power from PV panels is a waste if time. Those panels you have are probably only about 5-10% efficient. Your best bet is to harvest the sun with a solar water heater and pump that through the pipes under the driveway. This can be up to 80% or more efficient as opposed to the 22% max for the most expensive panels out there. This is a simple insulated box with a double or triple pane glass and a piece of metal with pipe attached to it and painted black so plate and pipe both collect sun. When you do not have to defrost the driveway you could route the heat into your house to decrease your heating fuel usage so there would be a secondary use for it. Use the solar panels and battery you have to drive a pump to move the water from the heater to the driveway or house. Use Glycol mix in the heater arrangement to avoid freezing. You can increase the efficiency of the solar water heater by making reflectors to direct additional sunlite to your heater. Joe's CD reflector is probably very good for this. Once you get the snow to the point where sunlight can shine through it, the driveway itself will also act like a collector and help to speed the process along if the sun shines on it. At that point you are heating from the top and the bottom. Also, if sunlight hits your driveway you could get some kind of black sand or gravel and spread that on the snow. The sun would heat the gravel and it would melt down through the snow until it gets to the surface at which point once again the driveway becomes the collector. When the snow is gone sweep up the gravel and get it ready for the next use. Sweeping up the gravel will be easier than shoveling the snow.
That's my thought.
Brian