Sunday, July 30, 2017

pushing electrons

The photovoltaic phenomenon is described as photons knocking electrons out of their valence orbital and creating a net charge in a semiconductor. There are holes, and dopants, and depletion zones, but I don't pretend to understand the nitty gritty physics of it. Sure is a handy property of semiconductors.

Lots of physics research, material science, high tech fabrication techniques, and government encouragement went in to the solar panels we installed this summer.

The key here, is that once the PV cells and panels are built, they keep generating electricity from sunlight for a really long time. Big payment up front, then "free" power for years.

I know that the federal tax credit for installing residential renewable energy is phasing out over the next few years, so decided to make our move now.

We are now producing our sun driven electricity, to the tune of 4.9 kW nameplate capacity. So far, our peak output was 4.4 kW, but don't know what has to align to get the full capacity. For the year, this is prime solar weather, as the winter and spring are more cloudy.

We decided on ground mount, as we have plenty of unobstructed southern facing land, and I'd just as soon not mess with the roof unless that was a much better option. I also had initially planned to design and build the rack myself. ( maybe another blog entry on how that went down).


Here I am, driving a Bobcat skid steer for the first time, with the 24" (600mm ) dia. auger for drilling the holes for the concrete piers. I am still a terrible operator, but did not kill the guys who came to help. It helped that they were both nimble and quick on their feet.

Here are the rack columns in the concrete forms, braced and ready for the  pour. The holes are six feet deep. This rack is not going anywhere.


The design for the rack required huge piers, totaling 2.5 cubic yards ( 1.9 cubic meters) of concrete between the three of them. I looked at renting a mixer and doing it by hand, but the cost was not that much higher to order the truck, and WAY less labor.

Had to dig the trench from the array to the inverter in the barn by hand. No fun in the heavy clay mixed with large rocks. Code requires top of conduit to be 18" (450mm) below ground.


Here is the finished array, soaking up the sunshine. The panels themselves are super easy to install ( as long as the rack was put up level, straight, and plumb!), and the cabling is all premade with simple plug ends. This particular design is a single string, 350VDC output with optimizers at each panel.

Pulling the home runs, terminating, tying in to the power panel were done by an electrician. I might have been able to figure it out, but he was way quicker than I would have been, and one of the grants we are going for requires a master electrician to sign off on it.

If we decide to go off grid, we will need to spend for the batteries, as well as the charge controller and a different inverter. We are a ways off from that, as we would need to reduce our load, and really do some self reflection on how much lifestyle change we would be comfortable with.



Monday, July 3, 2017

There are more things in Heaven and Earth, Horatio..........

https://en.wikipedia.org/wiki/Tacit_knowledge

This concept came to my attention the other day, and got me to thinking how it applies to our present society.

Tacit knowledge is knowledge that is difficult to transfer through written or spoken methods. Some examples are throwing a ball, playing an instrument, recognizing someone's face, or kneading dough. Many, but not all examples of tacit knowledge involve physical activities or modes of expression.

Since I have recently been trying to learn to identify edible plants, and to identify trees by their bark, I  find that words just can't cut it sometimes, and when it comes to eating a foraged plant, I darn sure want to walk the woods a few times with a pro until I finally see the essential differentiators of the plant, even if I find it hard to put in to words.

In the past, tradesmen, craftsmen, artisans took on apprentices, and over time, their knowledge was transferred, but was very difficult to codify.

In our ( at least in modern western countries) economies and social networks, things have become very written and oral and much less face to face or involve mind body coordination. Petabytes of information scurry around the world, as humans communicate and conduct commerce, but what is this doing, what has it done to our psychological makeup?

How does it affect our ability to empathize, to have a grounded feel for what might be true? The subtleties that abound in perfecting any new skill help one realize that sometimes the truth is too hard to capture on paper, and that maybe there are more things in heaven and earth than are dreamt of in our philosophies?

Are our brains being stretched to the limits by so much of one kind of learning , but much less of another? Why are those skills that involve kinesthetic intelligence or hands on craft abilities less prestigious or remunerated in our society?

The future I see is one where tacit knowledge transfer will regain prominence and will supplant the current mode of explicit knowledge transfer. In fact, further, the types of skills that are considered tacit knowledge will become much more important as muscle power and local economies slowly replace our fossil fuel driven economy.

Our education system has for a long time been losing its way, and not preparing our young for the real world they will have to navigate and earn a living in. Many are sensing that now, but how will the transition happen?




Thursday, April 20, 2017

descent engineering

My career before I retired was as an engineer for a large design/construction company. I helped build the energy industry infrastructure all over the world. If I had it to do over, I would not have contributed to the extraction of nonrenewable resources, but that's what happened, and time to move on.

Engineering has a very large number of sub disciplines, but the general categories are usually listed as civil, mechanical, electrical, and chemical. A few others that sometimes are considered top level categories are cost, biomedical, and systems engineering. If someone thinks another should be added, I'd not quibble. 

Engineering is still a very important human activity, but as with all other human endeavors, needs to be marshaled wisely, instead of being yoked to the short term profit driven economy we now "enjoy". Even from the long term view, our ability to take raw materials, and through methodical steps, fashion all manner of artifacts is amazing. During this fossil fuel enabled bonanza, we have been able to create millions of items, devices, and structures to make our lives easier.

As we face the end of cheap energy, the end of fossil fuels, and the general decline in easily extracted raw materials, we are on the cusp of a new phase in human history, and a large challenge in fashioning the artifacts that enables us to live in reasonable comfort.

So how will the engineering professions have to change? What do you do when the dozens of manufacturers ready to supply any component you need for your design are no longer there? What do you do when the advanced materials and techniques are no longer economic or even available?

I've begun a list of the new parameters that future engineers will need to consider and take in to account for their designs. This list is more on the technical side of things, and assumes that the ethical, sociological, environmental and systems thinking parameters are already a given. ( They are not yet, but that is a whole other post)

For that matter, will we even have "engineering" in the far future, meaning design using stress analysis, calculus, other forms of higher math, or will our built environment and artifacts be done at the level of craftsmen and passed down experience? I think for a generation or two at least, we'll have engineering, but it will have to change with the newly prominent parameters.

What are the new design parameters? How far down the road are they useful and relevant? How quickly will we be needing these new approaches? 

In no particular order, here are some. 

corrosion- Right now, nearly all ferrous things are just assumed to rust away as part of the natural way of things. Everything from ocean going ships to fencing to pipelines to cars are given some level of corrosion protection, but not enough to extend their lives beyond years or decades. Certainly not centuries or indefinitely. As iron ores and mining of same reach lower concentration levels, the continual input of new steel will end. We will be left with what we've refined, and must marshal it carefully. Any design will need to minimize the steel used, and make it very protected from rusting away. It would be a damn shame if we slid back to the stone age a couple centuries from now simply because we frittered away our iron.

longevity- Current economics dictate that many items are made to last about a day longer than the warranty. There will need to be a reevaluation on which items can truly be thrown away, made from renewable, quickly fashioned materials, versus items that have a lot of embedded energy, and should be made to last a very long time. There are old farm tractors made decades ago, that are still sound and operational, as they were built to last, and just need periodic maintenance and replacement of small components. Newer tractors have electronics, computers, and have had the weight trimmed to minimize cost, at the loss of longevity. They won't last as long without ongoing high tech support.

design for disassembly, maintenance, repair- this goes hand in hand with the longevity point. It also adds the issue that things should be repairable by the user, and not some tech center that will replace much more than necessary, just to do it quickly. The current approach makes sense when  labor is more expensive than replacement parts, but that will not be the case in the future. This approach to design may well mean first cost is greater, but life cycle cost is much less. In the future we are entering, life cycle costs will predominate, not first cost.

design for renewable inputs only-  where possible, some things should be designed from natural materials. This will limit the possible designs, but function will once again govern rather than form. Folks like Calatrava or Gehry will not be getting commissions. One can look at the amazing cathedrals and stadiums that were built hundreds or thousands of years ago to see that there is still much that can be done with stone and wood.


design for technology suites that won't domino- While it is hard to predict which ones with certainty, some technologies and fabrication techniques will be more likely to become impossible or vastly more expensive. Artifacts in the future should be designed so that they are not prone to single point failure in the supply chain. If semiconductor chip fab ends, then anything using them, even if for a simple sensor, might fail if this one single component is critical for function, so technology selection needs to consider only robust and simple components.

design for simple fabrication techniques- The extremely advanced fabrication techniques we have now are dependent on being part of a fully functioning industrial economy, so it's not just materials getting scarce, fab capabilities will likely degrade as well.

design for intermittent or batch production-  Many parts of our industrial ecology are designed to work 24/7 to make full advantage of the capital investment, and because many processes do not lend themselves to lots of stops and starts. Oil refineries and power plants run for months on end, only stopping for preventative maintenance. Factories, food processing, transportation, heck, everything in our society stops and starts whenever it chooses, because electricity and fuels are ready 24/7. If one starts relying on solar power for heat and or power, then one is forced in to the daily batch cycle, or providing very expensive storage and the associated additional conversion losses. Whatever industry we may have in the future will need to scale to the available solar time frame and energy density.

design for easy bio/tech split- ( McDonough and Braungart)- in their book "Cradle to Cradle", they point out how much of our environment pollution problems are because we mix the technical and biological ecosystems, causing it to be very difficult to recycle or compost. Design needs to keep these two material streams easily separated after an artifact has reached the end of its useful life. Europe is much further along in this area than the U.S. In essence, this concept takes recycling to its full closed loop conclusion.

I will continue to add more of these as they occur to me, but this is already a seismic change in what engineers normally have to consider in designing things.

Thursday, February 16, 2017

chicken predators

We are going in to the start of our third year raising chickens. We'll be ordering some meat bird chicks for starting in May, but figure our laying hens are still producing enough we will go another year with them.

 Chickens are plump, tasty morsels, and they can't fly or fight very well. So all manner of predators just love them. I had seen some signs of digging at the foundation a few times this past summer, and refilled the holes, but the hardware cloth I had buried did its job, and entry was denied. Overall, we'd been lucky, with no hawks, coyotes, or raccoons taking any.

Then...........this February, we had our first predator get in to the coop. Turns out weasels are really small, and after reading up on them a bit, I realize now that I could have avoided this, so had to start working to rectify things.

Here is what happened: First- the uneaten feed in the feeding troughs was attracting mice and rats, who helped clean things up overnight while the chicken slept in the roost. 

Second, they dug some tunnels from under the concrete slab section of the barn, providing access from a direction that had not occurred to me.

Third- they are food for weasels, who, by late winter, were getting  a might peckish. I had not minded the mice too  much, and when I saw signs of rats this late fall/winter, decided to start trapping. I got one, but then noticed that there were few new signs, and knew I hadn't scared them off, so wasn't sure what was going on. Maybe they were just getting more sneaky after one fatality?

Well, I now know that the rats attracted a weasel, who mowed through them, but with the rat's thoughtfully provided tunnel system, started taking a chicken every other night or so. 
(Weasels are actually a good thing to have on a farm, as they eat mice, voles, other critters who want their share of my garden. Just gotta keep them out of your coop!)

The first chicken had the classic weasel pattern, with the head nearly decapitated, but no the damage to the rest of the chicken ( what a waste!). I mixed up some cement, shoved it up under the slab where the rat holes emerged, and looked around for smaller holes than I had originally thought I would need to worry about. A couple days later, another two hens got it. I found a couple more holes and plugged them. Before it was all over, seven hens had been killed. 

Finally, no more hens were being taken, so I figured I had sealed all the holes. 

Then this happened

This beautiful, maybe even cute ( but blood thirsty) fellow went in to the rat zapper I had left on in another area of the barn, and got zapped. I had rather he hadn't gotten killed, and actually hope another one takes over his territory, to keep the rats away, just so long as he doesn't get in my coop.

You can see from his size that they definitely punch above their weight. It's surprising that they can take a much larger animal, but this stoat, ermine, or short tailed weasel ( all names for the same animal, you can see the black tip on his tail) is quite the fearless predator.

Anyone building a chicken coop- make it very tight, and if a rat can get in, so can a weasel.

Tuesday, January 31, 2017

cross cut sawyering

Our primary winter heating is with firewood, in our Russian furnace. ( masonry stove).

I cut and split my own firewood, using a chain saw for felling and bucking, and a maul for splitting.

I have been doing a bit of cross cut saw bucking ( cutting logs to firewood lengths), but am starting to get more serious about it. It's just one more step toward using less fossil fuels, and getting "functional exercise". I bought a new crosscut saw on line, and it works ok, but recently got an old one to add to my kit.

Turns out that sharpening a crosscut saw is more technical than I had realized. The definitive instructions are at this location, and what I have used for reference.

https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf77712508/pdf77712508dpi72.pdf

I am taking a couple short cuts to their complete sharpening system, ( sharpening a saw correctly is time consuming!) but after I get better at filing, I may spring for the jointer tool, and try swaging the raker teeth that need it.

To be clear, I am no expert yet, and have a ways to go, but am sharing what I've learned so far.

Here is my homemade saw vise. I copied the design from a friend who crosscut saws and is good at improvising quick and functional tools. This is an old crosscut saw I was able to acquire that was still in pretty good shape. It had a few teeth that had not been sharpened correctly, but mostly I was just resharpening teeth that had dulled.


One end of the vise. You can see the wing nut and support stand. The vise can be tilted to out of vertical to one side or the other if desired for better angle for filing. This saw has Tuttle, or Champion tooth pattern, better for cutting hardwoods. 




From left to right: 
a spider, used to check the cutting teeth offset.

 A feeler gauge, used to adjust the spider, and to check the projection of the cutting teeth past the raker teeth.

A triangular file, for dressing the underside of the raker teeth.

A flat file, for sharpening the raker teeth tops and the cutting teeth.

A peening hammer, for adjusting the cutting teeth offset
a straight edge, for spanning between the cutting teeth to check the projection past the raker teeth, used with the feeler gauge.

A mini anvil, used with the hammer to make the offset bend in the cutting teeth.



I am not ready to fell trees with a crosscut yet, but might work toward that if I practice two man sawing with a friend. I also acquired a felling saw, but it needs a lot of work, so it will be a while before it's ready to cut.

I guess it's obvious, but buck the wood while it's still green! I have some dead elm and a few seasoned logs that didn't get bucked when green, so I will use my chainsaw on them.

One more thing I learned, is that a "normal" saw buck stand as found on the internet is too low for crosscut sawing. To prevent hunching over while sawing, the log needs to be up higher off the ground than you might get away with using a chainsaw. This also makes the base wider, which helps resist the side thrust that crosscut sawing causes, unlike chainsawing. I had made a sawbuck a few years ago for use with my chainsaw, but just added leg extensions to it, to much better effect on my back. This is the design I built, but have since raised it a good two feet( .6m).

http://www.arboristsite.com/community/threads/how-to-build-a-folding-sawbuck.247300/




Sunday, December 25, 2016

The Resettling of America


Wendell Berry is a national treasure. He's a productive writer, and is also known for his environmental activism based on a strong moral sense and unique ability to state deeper truths. He is by far known for his poetry and fiction, but his nonfiction essays are what are most compelling to me. (Though I do need to read more of his fiction)

Wendell Berry's book "The Unsettling of America: Culture and Agriculture" was written in 1977, the year I was a junior in college. I read the book three years ago, at age 58, after having just bought 44 acres and returned to the land after decades of urban/suburban life.

In this book, he critiqued the long term trend here in America of urbanization. As more people moved from the land, farming changed into a fossil fueled industrial model.  People's connection to the land was no longer central, and a sense of stewardship was replaced by profit at all cost. He argued that the very fabric of our society became torn. He pointed out several governmental and institutional enablers for the trend. The great urbanization, and decline of family farms and rural America is still where we are today.

The wikipedia article on Wendell gives more info on his views and impact on our culture, so go there for more of that. My point here is to follow up on his observations in the Unsettling book.  He felt that the land grant colleges had become beholden to industrial ag, and no longer helped innovate and research ways for small farms to succeed. He also felt that the government itself was captured by corporate interests, and had abandoned the family farm.

I was part of the urbanization trend, and not so much by choice. Small family farms were going bankrupt in the late seventies, early eighties, and it looked like a dead end trap to many of us farm kids. None of my brothers or I stayed on the farm.  



But now, in 2016, I think we are beginning to see a reversal of the urbanization trend, and I do not mean white flight to the suburbs. While the rural/urban split is still the norm, I have begun to notice that young folks are recognizing the suburban lifestyle feels like something is missing.

As our economic empire slowly declines, there are less opportunities for them in the "knowledge economy", and the service sector is a rigged game and a poverty trap. Living where I do, I have met many young folks who have moved to the area with no more to their names than a car, some clothes, and a glimmer of an idea. They are determined to figure out how to make an intentional living by growing food, and reconnect with the land.



Of course, long term ( two to four hundred years, give or take? ) , resettling the land as a more agrarian culture and economy will be inescapable as fossil fuel enabled mechanization will become more expensive, and eventually very minimal. Human and animal labor will replace hydrocarbons to an uncertain extent over time. We should recall that at one time, well over 50% of the population worked at farming, and they fed the rest of the population. It's not like human scale farming is an unknown thing. It will be fascinating to see what blend of traditional ways and more recent knowledge our future farming will become.

In the coming years, we will once again learn the true cost of food. 

Now is the time to get back through the learning curve of farming without diesel fuel or synthetic fertilizers. Much of the knowledge is still out there, ( I live near Amish, who farm with horses, as well as some homesteaders who are off grid and making a go of it) with a few practitioners already leading the way, but it needs to be spread and shared, and above all, practiced. I find that leafing through the books gives me a good start, but real hands on experience is irreplaceable. I personally am only early in my journey, but know where I am headed.

We are at the very early start of another great transition, and in some ways, it is exciting, but no mistake, weaning off of fossil fuels will be painful and a hardship. The earlier we start, ( with the training wheels on, so to speak) the easier it will be. While inescapable, the reestablishment of community and local connections will be I think a positive result.

( As a post script, I am aware that this reflection is only about the European experience, and does not address the fact that the continent was already fully settled and in equilibrium with the land before we arrived. I may post thoughts on that sad genocide some other time)






Sunday, October 23, 2016

fanning mills

Well, I just today did my first Craig's List purchase. My kids are embarrassed but accepting of my backward "technophobe" behavior, and I still haven't bought anything through ebay, but this item was too intriguing to pass up. 

I have been researching manual threshing, winnowing, and there are not a lot of recent or current developments available. There are one or two gems shared on youtube, and lots of klutzy half hearted gadgets, but no commercial options, or detailed plans. There are a few commercially available "desktop" electrically powered seed cleaners out there, but they are pretty expensive. Of course India and China are teaming with businesses that would appear to be cranking out small scale agricultural equipment, but how does one get more detail than a fuzzy image on the screen or find a local distributor?

So I bought a fanning mill. It is in fairly good shape, and I see what needs repair, and feel confident I can make the fixes.

We are currently growing dry beans for soups, and have been hand threshing, shelling and winnowing. We have the time, and it's not that bad to sit and shell pods for a while each evening, but as we begin to do more and more food preservation and start growing small grains, our time will need to become more efficient.

The one I bought was made by Johnson and Fields, a fairly prominent brand at the time. The model was named the "Racine". The history has been hard for me to track down so far, but apparently Racine Wisconsin was a hotbed for fanning mill manufacturers, so Racine almost became a generic term for this general style of mill. At one time, there were scores of fanning mill makers, and thousands were sold every year for about 40-60 years. 

The history of fanning mills here in the states is interesting for a few reasons. They were first invented in the late 1700's, and as the fertile midwest and great plains expansion happened in the 1800's, there were thousands of small farms needing more efficient ways to process small grains for seed and for market. Going from flails and winnowing baskets to fanning mills was a big step, but once steam powered threshers started coming into agriculture, these fanning mills got tucked away in the barn, or left outside, nearly all to eventually rot and disappear. Seed cleaning is now nearly all done by commercial grain elevators, but there are still a few farmers out there, especially in the upper midwest grain belt that clean seed using electrical powered modern equipment. 

Here is the fanning  mill. You can see the overall shape and size here. 


Here is a closeup of the hand crank, gearing, and the fan blades inside the housing. I plan to change from hand crank to pedal power. The bushing where the crank mounts through the wooden support leg is wallowed out, so I need to fix that.


Here are the screens and the exit point for chaff. I've pulled out the screens for repair and to get dimensions so I can order screen with various sized holes/mesh.



A view of the fan housing from the other side. The fan axle is steel, all the other fan components are wood.


Here is the feed hopper. A screw adjustment allows setting flow rate to optimize speed without overloading the screens.


I will do another post in the future to update with repairs made and our first winnowing trials. Maybe next spring I'll plant what Gene Lodgsdon called a "pancake patch". Just enough wheat to make flour for pancakes on occasion.