Solar Powered, Geothermal Heated Snowless Driveway and Walkway

Geothermal / Radient Heat

Snow and ice covered driveways and walks have been plaguing man for many winters now. we have created tools and machines to assist us in our efforts of snow removal, but they still require bundling up and facing the cold. Would it not be wonderful to watch the snow melt away as it lands on your walk, no matter what the current weather conditions? I think I have formulated a solution to achieve this kind of winter wonderland.

To get started we will be discussing to types of heating systems; geothermal and in floor radiate heat. Then we will combine them as one and use them in a different way then normal, let us begin.

Geothermal Heat pump / Ground Source Heat

A ground source heat is an alternative energy heating and cooling system that uses the natural heat of the earth to heat and cool our homes. The concept is simple, below the frost line the ground maintains a constant 65 degrees F. Water or a water antifreeze mix is circulated in pipes that are buried below the frost line or deeper, they are connected to heat exchanging unit in the home where the heat from the earth that has been transferred to the water is used to warm the home. In some cases the water may be heated by other means ( lp, natural gas, electric)once in reaches the exchanging unit. This is actually an efficient way to heat your home, due to the fact that you are only heating the water from its already warm 65 degrees.

In Floor Radiant Heat

In Floor Radiant heating is a heating system which uses heat conduction to warm the floor then the heat rises and warms the room. Most commonly these systems consists heating and circulating warm water in a closed system of pipes. Similar to our previously discussed ground source heat, water is used as the medium for heat transfer. I believe that a combination of these system has been used before for in home heat, but we are talking about warming our walks to melt snow.

Now on to the system.


Snowless Sidewalk

Now to the topic at hand, there may be a system that does warm the walks and melt the snow as it falls but what I am purposing here is a system that uses little to no additional energy. Combining these to effcient heating systems to create a warm, snow resist, shovel free walkway is easy. Frist we aquire some tubing like that used in the ground source system and that used in the radient floor system and design a system of circulation. Then using the figure below as a guide we will need to bury some of it below the frost line and lay some in the poured concrete of our walks and ways. This will need to be done at the time the walk and driveways are poured or the exsisting will need to be destoyed and replaced, unless you can figure out a way to lay the tubing under your exsisting walkways without damaging it (if you do let us know). I will guess that a 4 to 1 ratio of tubing will be sufficent to accomplish our goal. This means we will bury 4 foot of tubing for every 1 foot in the walkway. We will also need a pump to circulate the water and a few valves for maintenance access and system bleed. I suggest laying the tubing in a zig zag pattern with about 8-10inch gap between lines, see figure for illustration. Now our goal is to keep the walk way surface above freezing which is 32 degrees F, so if the water from the earth is 65 degrees then there should be no need for additional heat. With that in mind the only energy require to run our system is a small amount of electrical for the circulating pump. Any small electrical pump will work just fine. For complete efficiency I suggest a small DC pump and small solar panel kit and battery to run it, this can provide circulation at no additional cost. Now you can sip your coffee while standing in the window watching your neighbors shoveling their walks in the freezeing cold.

This hub it not very detailed or specific and the contents are purely speculative and theoretical. This design has not been proven or tested in anyway. I in no way claim to be an expert in the areas I am about to discuss. I also take no responsibility of damages or expenses cause by the implementation of these ideas. I recommend researching the two heat systems mentioned before attempting to build a system like this. I also recommend professional asssistence in any DIY project.

With all that said I am greatly interested in comments and discussion from expert individuals who have or are willing to experiment with the following idea.

Thanks for reading, I look forward to your comments.

Design layout

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Comments 14 comments

Ben Zoltak profile image

Ben Zoltak 6 years ago from Lake Mills, Jefferson County, Wisconsin USA

I like theory pieces! Cool work Ben. I can see this application, I especially like your section:

"For complete efficiency I suggest a small DC pump and small solar panel kit and battery to run it, this can provide circulation at no additional cost. Now you can sip your coffee while standing in the window watching your neighbors shoveling their walks in the freezing cold."

I can see a lot of older folks especially, who rely on private individuals to plow their lawns, making use of this technology. The solar panels are the cherry on top.

Well done.

Ben


helene.bliss 6 years ago

Great hub! it is very interesting and really caught my attention.


Christien Stone 5 years ago

I'm glad to see someone is thinking along the lines that I am. I have been thinking about using geothermal to keep walks and drives clear for about a year now. I'm a landscaper and being able to offer a system that should be installed before work is completed makes a lot more sense to a lot of people.

Your system, from my point of view, a little back up plan glycol, should work fine. I'm not any sort of expert in the field either, just have a lot of experience making sure frost doesn't move my stonework. I also pondered burying a sealed unit about 5 feet down which could contain all necessary material.

My system design is in another direction though. Trials will be done this coming winter. Hopefully I'll be able to chuck the snow shovels.

Good idea,

Chris


JOE FIORETTO 5 years ago

I AM LOOKING FOR A SYSTEM FOR EXISTING DRIVEWAY WHICH IS PN A SEVERE INCLINE FOR A SYSTEM AND CONTRACTOR IN NW ILLINOIS WHO DOES THIS KIND OF WORK, AND A BALL PARK DOLLAR AMOUNT SO I KNOW WHAT I AM GETTING INTO.THE DRIVEWAY IS 3 CAR AND ABOUT 69FEET LONG THANK YOU


blackmarx profile image

blackmarx 5 years ago from Rice Lake, WI Author

Christien Stone thanks for the comment. This was just something I worked out off the top of my head. it would be nice to see it work with our any additional energy cost.


Don Flumerfelt 4 years ago

I want to try this! My driveway and walkways are made from dryset bricks so retrofitting is certainly feasible. Would the pump really be necessary? Would not convection alone keep the surfaces warm?


blackmarx profile image

blackmarx 4 years ago from Rice Lake, WI Author

Don Flumerfelt, you could try it without a pump, I feel the pump would increase the effectiveness and ensure circulation and good heat exchange. If you do try a system without the pump please let us know how it works for you, and you may want to plan your system for the addition of a pump later if the convection does not work. Good luck, and thanks for the comment.


Dave 4 years ago

I think you need a pump. The pump-less process you describe is called thermosiphoning. Thermosiphoning would probably work if the opposite sides of the loop were differentially heated but in this case that would not be so. The top and bottom portions of the loop would be differentially heated - warm low down, cold high up, but it's a closed system. So, in the simplest case - a single loop - the warmer coolant on the right side in the lower part of the loop would want to rise, which would exert pressure through the cold upper part of the coolant to bear down on the left side of the loop. Problem is, the left side of the loop low down wants to rise with equal pressure, transferring back through the cold coolant in the top part of the loop, and bearing down on the right side of the loop with exactly the same force the right side of the loop is exerting upward. Net result: no coolant movement, because the forces cancel out. Now, if you could figure out some way to differentially heat one SIDE of the loop rather than having the top and bottom heated differentially, but equally, within their respective zones, you might get a thermosiphon going.

As an aside, that would only work in a gravitational field, but fortunately, there's gravity everywhere on Earth. In outer space, heating any part of the loop would only warm the locally heated area, and increase internal pressure within the loop, but thermosiphoning would not occur because the expanding heated coolant would exert equal pressure both ways around the loop. Thermosiphoning only works because of the tendency for heat to rise and heat can only rise where "up" exists, i.e. in a gravitational field. Outside a gravitational field, there is no "up", so heat can't rise.

Isn't physics wonderful?


blackmarx profile image

blackmarx 4 years ago from Rice Lake, WI Author

Thanks Dave for your wonderful explanation. I was thinking along those line.


Fort Collins Colorado 4 years ago

Perhaps a buried holding tank, connected to a passive hot H20 solar panel and a PV panel to power the DC pump. Add alcohol to the system (can get to -17 here) and slightly bevel the sidewalk surface allowing runoff rather than evaporation. Thoughts?


blackmarx profile image

blackmarx 4 years ago from Rice Lake, WI Author

thanks for the good ideas.


Logan 4 years ago

I've had this notion before too. :o)

Dave, what if the system were a closed loop of air? Similar to the envelop house concept.

As far as powering a pump, solar is not the only renewable power source, there is also wind and piezoelectric.

My thought though, is if you're going to install a solar/wind/piezoelectric power generator to operate a pump that has to generate enough force to pump so much volume of fluid or air, why not just set up an electrically heated sidewalk in the first place?

From http://www.drivewayheating.com/site/page/heated-dr...

"At the recommended spacing of 4 inches, the average operational cost is approximately $.28 per 100-square feet per hour. This is based on a 35-watts per square foot snow melting system, with a kilowatt hour rate of $0.08 per hour.

When using the recommended heat cable spacing of 4 inches for a heated driveway, a 240 volt 30-amp breaker is needed for every 175 square feet of snow melting system."

BTW, have you seen this? http://creativemachines.cornell.edu/node/116 another concept I've thought of after a visit to Hawaii. Hawaii should be able to produce all their power from wind, wave, and solar power. They are right in the path of the trade winds. But folk find the wind turbines ugly and a blight on their scenic views. This got me thinking, what if we made artificial trees that generated power as they bend in the wind and rain? cover the leaves and branches with PVC's and you get power from light as well.


Ben 2 years ago

I have been working on this for a while, and once I can get comfortable with the engineering, will install (anticipated 2016) and have a couple additions to the article.

1) My concrete will be dyed black to absord as much heat from sunlight as I can.

2) There will be insulation under the concrete.

3) The driveway will have 3 tracks. 2 where tires go and 1 in the middle. The middle track will be dyed cement without sand (Just stones and cement). This will drain the water. Lastly, the middle track will have no insulation underneath it.

4) The ground temperature under the frost line is usually closer to 54 degrees.

5) The ratio of 4:1 is probably closer to 3:1 given the NJ Geothermal study here http://geoheat.oit.edu/bulletin/bull21-2/art4.pdf (Look on page 14) which uses 2:1. The NJ project removes 1/4" an hour on average and has a ground temp between 48-57 degrees.

I am considering adding a heat exchanger to the system. Running my closed loop driveway system, thru a heated (from a wood burning pot-bellied stove) well. This would allow me to 'boost' the system when snow exceeds 6" in 24 hours. In lower Michigan, this is typically a once or twice a year event.


BGri5th 4 months ago

My descent into madness continues....I am now more familiar with the engineering behind why this idea wont work. Essentially, the cold fluid in the driveway cools your wells and reduces (an already minimal) heat exchange from the ground. The BTU output is WAY to low to melt anything. It will not even accelerate the melting in any meaningful way. Sorry.

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