Green Energy Experimenter

Ever get a rounded off bolt? Normally, I’ve JB welded a nut to it, waited for it to cure, and hope it bonded well enough to remove the bolt. On top of all that, I never have what I need and have to make a otherwise needless trip into town.

I recently bought a used vehicle and decided it would be a good idea to change the oil. As luck would have it, the oil plug bolt was rounded. I tried pounding a socket over it to remove it, but it didn’t do the trick. Upon reflection, it dawned on me that a pipe wrench can grip round pipes, so why not a rounded bolt head? Check out this video for the results:

Shopping in thrift stores to some might be a embarrassing thing to admit to, but to each his own. I enjoy checking out the electronics while my wife looks for clothes. Occasionally I find something I can’t pass up. Like this UPS I picked up for 5 bucks:

UPS found at thrift store

For those who don’t know, a UPS means Uninterruptible Power Supply. Your electronics plug into the device and it in turn is plugged into grid power. A good UPS like this one will filter the wall current leading to better power for your electronics. When the grid power goes down, a small battery runs an inverter in the UPS, giving enough time for you to save your work and shut your computer down properly.

I bought it knowing the battery would probably be shot, but the inverter should be intact. Sure enough, the battery was toast. I can pick up 10 cents a pound on the battery at the local scrap yard. The inverter works flawlessly. The great thing about this type of inverter is the efficiency. These run around 96% efficiency as opposed to 87% from your typical inverter. There is no cooling fan, lending credibility to the manufacturer’s efficiency claims. These also seem to put out a better signal. Some disadvantages are the size and weight of the unit and the fact that it only has a 250 watt output.

Inverter output side

Still, 250 watts is enough to keep a laptop running, run a fan, etc. By swapping out the battery for a larger one, you can increase the run time of the unit. Here’s the old battery:

Battery from the UPS

These are supposed to be replaced every 3 to 6 years depending on the environment and usage. What I’m going to do is wire a 12v cigarette plug to the UPS through the case. I can then attach it to my lawn mower battery with the alum electrolyte.

Alum battery running my cheap inverter from a computer UPS

As you can see, I’ve got an entire 250 watt system that cost me under $10 to build. The 150 watt inverter I destroyed a couple weeks ago cost me $20. There are a couple of ways to recharge the battery. First, you can use this as a backup system. The UPS will recharge the battery and keep it floating when plugged in. The other way is to leave the unit unplugged and recharge the battery from solar, wind, or some other energy supply.

I hope this gives you an idea of how cheap a small alternative energy system can be. Don’t be shy about thrift store shopping. Part of being “green” is repurposing old equipment. If done right, you can save money and keep the landfills a little less full.

This isn’t necessarily a energy project, but it does involve saving money and doing things with your time, so I’ll go ahead and post it for what it is worth. My wife and kids have recently acquired an interest in astronomy, so I decided to build a simple telescope to see if the interest would grow. Unfortunately, the place I ordered from sent me a wrong lens so the resulting telescope isn’t quite what I had in mind. The one I ordered had a focal length of 100 cm, and they sent me a 30 cm one instead.

Homemade Telescope

Focal length is one of the important ingredients of a telescope. To calculate the magnification, you simply divide the focal length of the objective by the focal length of the eyepiece. My eyepiece lens has a focal length of 5 cm.  Dividing my objective of 30 cm by the eyepiece of 5 cm, you obtain 6x magnification. I originally planned on 20x, and will do so when the new lens comes in.

The size of the objective also is important, the bigger the lens, the better the light gathering and resolving power. I’m using 50 mm lenses for both the objective and the eyepiece. The problem with this build was that I cannot purchase 50 mm inner diameter pipe locally.

To make up for this, I purchased some 2″ PVC pipe, which has an inner diameter of 2.047″. 50 mm is 1.96″. To make up the difference, I cut a 3/4″ piece of the 2″ pipe and cut slots at 90 degrees from each other. I then glued 1/4″ long pieces of rubber band in the center of each quarter.

Homemade lens holder

The lens is then placed into the piece of pipe, held in place by the rubber bands.

Lens in mount

To make the lens more secure and to attach the lens to the telescope tube, this lens holder is then inserted into a 2″ coupling. As the lens holder is pushed deeper into the coupling, it tightens and holds the lens in place. The coupling is then pushed onto the telescope tube and held in place by friction. This allows the lenses to be adjusted for focus. One is made for the objective and the other is made for the eyepiece. To make this simple, I used a 50 mm lens for the eyepiece. To get higher power and better images, you can use bushings to reduce the 2″ pipe to fit smaller lenses.

Lens mount attached to tube

To get a more stable image, I drilled and tapped a 1/4″-20 hole in the tube so I could attach it to my portable camera tripod as seen in the first picture.  The tripod is fairly stable with the legs retracted and placed on top of a car.

1/4″-20 hole for tripod mounting

Since the objective focal length is fairly small, this telescope has a good amount of chromatic aberration. This is caused by the glass bending different wavelengths of light at different angles. By having a longer focal length, you can lessen this effect. There are better ways of overcoming this, but it is beyond the scope of this article. The eyepiece being 50 mm causes some distortion around the edge of the lens, but you still have a good field of view in the center. As mentioned before, you can use smaller lenses that will work better for the eyepiece to overcome this. Another thing is the image will be upside down, like most telescopes will do. Here’s a picture shot through the telescope with my cell phone:

View throught the homemade telescope

When my new objective comes in, I’ll take a picture of the same thing through it to compare. If I have a clear night, I’ll take a picture of the moon through it so you can see its night time performance. Hope that gives you some inspiration on building your own telescope.

My old woodgas stove cooktop design was too tall to be really practical. I have trimmed it down, making it much easier to pack around. It also heats better with the cook surface being closer to the fire. Take a look at it now:

Woodgas stove with cooktop

The cooktop now only adds 2 inches of extra height to the overall setup. By comparison, the old design amounted to two coffee cans stacked on top of each other. Here’s the internals of the entire system:

Parts of the woodgas stove

On the front row left to right, you have the feed ramp and intake blower. The forced air induction boosts the heat output by a significant margin and is easily powered by a 9v battery. I normally just use my alum battery when I use it in my backyard. On the back row left to right, there is the cooktop, the burn chamber, and the outer shell. The cooktop is made from a cut down coffee can and the outer shell is made from a coffee can with a hole cut in the top for the burn chamber and another hole in the side for the blower.

The burn chamber is made from a quart sized paint can with 1/2″ holes drilled at random in the bottom and sides. To give an idea of how long these things can last, I’ve been using this same can for a year and a half. This slides into the outer shell. The blower forces air into the area between the outer shell and burn chamber, preheating the combustion air. The end result is a fairly efficient camp stove that is suitable for outdoor heat and cooking, all smoke free.

Another important part of this design is the feed ramp. Most woodgas stoves run in batches, so if your food isn’t cooked or your water boiled, you have to remove the pot, add fuel, and get the fire going again. With the forced air induction and feed port, you can keep the fire going as long as you like. The feed ramp ensures that the fuel goes into the burn chamber:

Woodgas stove feed ramp

In the above picture you can see how the feed ramp extends downward leading to the burn chamber. The fuel is fed through the port and down the ramp. There are 4 ports at 90 degree angles to each other. This enables 4 people to sit around the fire and enjoy a lot of warmth while food is being prepared on top. The ports are also great for roasting hot dogs or marshmallows.

Smoking trout and keeping warm around the woodgas stove

As you can tell, there is a lot of heat output. On the top, I have my smoker with a couple trout being prepared for dinner. You can see 3 out of the 4 ports going full blast. If you don’t want to produce extra heat, feed it just enough fuel to prevent the flames from going out the sides. For those of you that haven’t seen my fish smoker, check out the following video (which shows the old cooktop):

While I had a bit of a set back with my battery charge experiment, I have figured out how to use the parasite’s ability to charge capacitors. I have successfully ran a modified joule thief circuit off the parasite:

Pretty brief flashes of light, but this means I will be able to trickle charge my AA batteries using nothing more than power scavenged off CFL lights. Another benefit of using capacitors with the joule thief is that you can run the circuit directly off a small solar panel, boosting its output, which should enable you to charge batteries in low light conditions.

Another thing I plan to do with this circuit is to tune it into strong AM radio stations to get free for me electricity. Is it possible with the right antenna to harvest other forms of electromagnetic radiation? Hmmm….

This experiment has met with some success and failure. I checked the battery charge on a regular basis for a couple of hours and within that time, it went from .585v to .822v. Pleased with the progress, I left it alone for another couple of hours. I checked it at 9:34 PM and it had only gone to .880v. I then began to monitor it, and by 9:41 PM, it had dropped to .877v. I’m not sure what the peak voltage was, so I decided to pull the battery off the charger to see what I could do with the energy it gained.

To my disappointment, the joule thief flashed, and shut off. The battery seems to be defective, not really surprising for a NiCad battery that had been left for a year. I’ve tried playing around with other batteries, but the charge seems to stall out when 1v is approached.

On the success side, I hooked up a capacitor to charge this morning. After charging for an hour, the voltage is now up to 14.56v. It seems that capacitors do better on this circuit than batteries do. I guess I’ll have to order some supercapacitors and see if I can come up with a more reliable way of charging batteries with this setup. I’ll continue posting updates as this project develops.

I’ve been playing around with circuits that can gather waste forms of energy and turn them into something useful, in this case charging a AA battery. The components are very cheap, 4 switching diodes, 2 ceramic caps, and 2 electrolytic caps. A antenna wire is needed to pick up the signal and a ground wire is needed to create an electrical difference. I call this circuit the parasite, since it leeches off wasted energy from electric circuits. Here’s what it looks like shortly after I hooked it all up:

The parasite right after hook up.

The source of wasted power is a CFL light bulb. These are a great candidate for energy harvesting because of the small transformer found inside them. They also tend to get used for several hours each evening. Here’s how I ran the antenna wire to my workshop light:

The antenna wire for the parasite.

I connected my ground wire to the ground on an extension cord plugged into my house wiring:

The ground wire for the parasite.

This is what creates an electrical difference making energy production possible. If you detach the ground wire, the circuit ceases energy harvesting. If you detach the antenna, the circuit produces very little power at all.

So how well does it work? Based on my observation, it is capable of charging a nickel cadmium cell at a rate of .12v/hr. I started the experiment at 5:23PM at .585v. It should be up to a full charge of 1.2v around 10:30 tonight. I’ll post updates as this experiment progresses.

The parasite after 10-15 minutes of charging.

While the power produced is small, it is enough to charge your the batteries in your small electronics for free. The charger only cost a couple dollars to build and uses energy that would normally go to waste. When you consider all the sources of electromagnetic fields all around us, you’ll realize the potential that derivatives of this circuit have.

Stainless-Epsom Secondary Cell

In researching easily-made secondary cells, I came across a most excellent Youtube channel called Lidmotor. He has made a cell using epsom salt (magnesium sulfate * 7H2O) and cheap stainless steel scrubbers. I’ve kind of duplicated this cell by splitting one of these scrubbers in half to form the electrodes. I made a highly concentrated electrolyte with distilled water and epsom salt. To prevent the electrodes from shorting out, I spaced them with a folded paper towel. All of this sits in a canning jar. To charge, I hooked it to a 12v battery charger and let it off gas for a couple of minutes. Here’s the cell running a LED through a joule thief:

Stainless steel and epsom salt secondary cell.

It is a fairly low current cell, but it manages to run the LED for quite some time. One strange behavior, also noted by Lidmotor, is the dramatic voltage rise when the load is removed. After sitting without a load for several minutes, it can again power the LED for quite some time. Interesting, and it deserves more experimentation. I have a higher capacity and more durable cell design in the works right now.

Lead-Epsom Cell

While reflecting on the chemistry of the stainless-epsom cell, it dawned on me that magnesium sulfate just might make a electrolyte suitable for use with lead electrodes, much like my alum cell. The benefit of epsom salt is that it is far cheaper than alum and even safer. I cast some new lead electrodes, this time smaller than the ones I had experimented with previously. Another thing I did a bit differently was to rough the surfaces of them with a wire brush to increase the surface area, thus increasing the capacity of the cell.

After forming the electrodes with a 12v charger, I hooked it up to a joule thief. It performed quite brilliantly and lasted longer than the alum cell did:

Lead epsom cell running a LED through a joule thief.

Based off the initial results of this cell, I think my mower battery deserves an electrolyte swap. It has undergone 8 charge/deep discharge cycles and is still going strong. The alum electrolyte seems to be a good way to get a longer life out of old lead acid batteries. I hope that epsom salt will work just as well, if not better, as it is far easier and cheaper to obtain.

You may notice the little circuit to the left of the joule thief. This is another project I’ve been working on that so far has been successful in harvesting energy from electrical fields found in my house. I’ll be posting more about this experiment in the near future…

There seems to be a lot of legend associated with rocket stoves. I often hear of a rocket stove as being something you can put a tiny amount of wood in and magically heat your home. While a properly built one is capable of high efficiency, one has to keep in mind the limited nature of the fuel being fed to it. Let’s consider a good hardwood that most of us have access to – oak. On average, across species, seasoned oak will have at least 6200 BTU per pound. So if our rocket stove burns that amount of wood with 100% efficiency in an hour and transfers that heat energy to the air with 100% efficiency, our best output is 6200 BTU/hr. The real number is going to be lower. Let’s figure efficiency off the fire and exhaust temperatures. Supposing the hottest combustion temperature is 2000 degrees and your measured exhaust temperature is 200 degrees. This is going to give you a 90% efficiency, which gives us a real world output of 5580 BTU/hr.

To put this into perspective, that is just a bit more heat output than your run of the mill space heater. Can you heat your entire home off a space heater? Contrary to what certain manufacturers claim, the answer is no. You can maintain a 45 degree temperature difference in a 1152 cubic foot room (the volume of a average sized bedroom) with that kind of heat output. To heat your average 1200 sq. ft. home, you’ll need something between 30,000 and 40,000 BTU to maintain good heat in the winter.

What does that 45 degree temperature difference mean? Let’s say the average overall temperature is 25 degrees outdoors. With a 45 degree difference, you’ll have a nice comfortable 70 degrees inside. You’ll need between 5 and 7 pounds of wood an hour to do so, even with a 90% efficient rocket stove. At this rate, you’ll go through a cord of wood in a month. That’s with a 90% efficient stove and a well insulated house.

If you want to heat your indoor air, regardless of the type of stove, you are going to have to burn a lot of wood. So where do people get the idea that rocket stoves are miserly on wood consumption? The answer is in the rocket mass heater. Instead of heating air, they focus on heating your personal space. People who use them dress warmer and maintain a much lower temperature differential. With a blanket over you, sitting on a bench that doubles as the thermal battery, it doesn’t take much energy to keep warm at all. Kind of how a heating blanket can keep you warmer with 130 watts than a 1500 watt space heater can.

For a great read on heating your personal space vs. air, check out this great link: http://www.richsoil.com/electric-heat.jsp

It seems that people confuse the term rocket mass heater with any type of rocket stove heating system. While all rocket stove heaters have a rocket stove at their core, how they handle the heat output is where they all differ. I believe some clarification is needed starting with this popular term:

Rocket Mass Heaters

Rocket mass heaters use a rocket stove to efficiently burn wood. The hot exhaust is then tunneled through a maze like pipe that goes through a thermal mass. As it does so, the heat is transferred from the exhaust to the thermal mass, where it exits the outside relatively cool. So what is this thermal mass? Think of it as a battery for heat instead of electricity. It is made of materials such as rock, brick, and cob that absorb massive amounts of heat and then slowly release that heat energy to the surroundings. Many people have turned this thermal mass into something decorative and functional by styling benches and furniture out of it.

Rocket mass heaters have the advantage of only needing an active fire for a couple hours at a time throughout the day. By burning a hot fire for a couple of hours, the thermal mass is recharged and can pump heat slowly into the room for several more hours to come. Once the mass has cooled, it is time to start another fire and the process continues. To balance the slow steady heat release of the mass, often rocket mass heaters will incorporate a radiant system to provide quick room warm ups when the fire is going. This is often in the form of a metal barrel placed over the heat riser. This provides a quick heat transfer to the room and a cooktop to boot. This radiant system brings me to the next type of rocket stove heater.

Radiant Rocket Stove Heaters

Most radiant type of rocket stove heaters are small and are used to heat garages and workshops quickly. As mentioned in the previous section, sometimes they form a hybrid with the mass type heating systems to provide quick heat. Typically, these tend to be a bit inefficient because they are often built without insulation. The lack of insulation leads to more combustion byproducts. By taking time to add insulation, their efficiency can be improved and the exhaust made cleaner. Heat from the exhaust is radiated to the surroundings by exposed metal surfaces from the stove and pipe, much as is the case in traditional wood stoves. Between often times lacking insulation and a lot of heat escaping through the exhaust, the radiant rocket stove heaters are of dubious advantage over traditional wood stoves with a small hot fire.

Forced Air Rocket Stove Heaters

By building a small insulated shed around a rocket stove with the hot exhaust passing through a couple of barrels, one can build a outdoor forced air furnace. A blower transfers the cool indoor air around the barrels, heating the air, and transferring it back indoors. With a well made rocket stove, efficiency can be better than commercially made units. The main drawback to this system is that air is a poor heat transfer medium and those blowers consume a decent amount of power to do so. The main advantage is simplicity.

Rocket Stove Boilers

By placing a coil of pipe above the heat riser in a rocket stove and pumping water through it, a rocket stove boiler can be made. From there, the hot water can be pumped into a in-floor radiant system, radiators or baseboards, or a heat exchanger in an existing furnace. It is for this reason that I recommend rocket stove boilers for most people with existing homes. The main drawbacks in a boiler system are complexity and cost. Much of this is offset if you are using one to replace an existing boiler and using the remaining system.  The advantages are the fact that they are easily integrated into existing homes, can heat greenhouses, barns, pools, etc., and can provide domestic hot water. It is the type I chose to use myself for these reasons.

Conclusion

So we see from all this that not all rocket stove heaters are the mass type. Which one is best for you depends on a lot of factors. I hope this makes you able to make a better decision when choosing one for your needs.