Post G23-008: Simple geometry of sun and shade, or, keep your gnomon pointing north.

 

This post is about making sure my new garden beds don’t end up in the shadow of my back porch, during the summer.  Based on the length of the shadows today, in late winter.  And, ultimately, based simply on the height of the porch roof.

To cut to the chase:  If you use Excel, and the NOAA sun-angle calculator, you can accurately predict the length of a shadow, for any date and time, anywhere on earth, via this formula:

Shadow length = obstruction height * cotangent (solar elevation angle in degrees * π / 180)

The π / 180 is there because Excel wants to see angles expressed in radians.  If you’re using a calculator that accepts angles in degrees, omit that.

 

Continue reading Post G23-008: Simple geometry of sun and shade, or, keep your gnomon pointing north.

Post #1716: COP out. Does it ever get cold enough, in Virginia, to make gas heat cheaper to run than a modern heat pump?

In Post #1706, I determined that, for heating my home here in Virginia, it was far cheaper to run my heat pumps than to run my natural gas furnace.  That’s based on costs of $1.70 per therm of natural gas, and $0.12 per kilowatt-hour (KWH) of electricity.  Like so: Continue reading Post #1716: COP out. Does it ever get cold enough, in Virginia, to make gas heat cheaper to run than a modern heat pump?

G23-006: The sunniest spot in a shady yard? Part 1, geometry.

 

This is the first of two posts on finding the sunniest spot in a yard that has shade trees on either side.  This one uses geometry.  The next one will use time-lapse photography on a sunny day.

With any luck, both approaches will tell me the same thing.

If your yard is bordered by shade trees, locate the beds so that due south (180 degrees) splits the compass bearing from your bed to each line of trees.  This gives a surprising-looking result for my back yard.  It’s not at all what you’d naively think, just looking at the trees and the yard.

Garden bed location 1:  Wrong.

I started gardening seriously during the pandemic.  Temporary raised beds were made from recycled campaign yard signs and bamboo.  I placed those in seemingly-reasonable locations in my back yard. In part, they were filling in low spots on the lawn.  But it seemed like they were located so as to get the best sun.

I’m now getting around to putting in something more permanent.  This time, I’m not going to wing it, but instead want to know what spot in my back yard gets the most sunlight.

It’s not obvious.  I have tall trees on either edge of my yard.  And, interestingly enough, what appears to be the obvious solution — locate the garden beds in the middle of the yard, away from both tree lines — isn’t even close to being right.

So, eyeball a couple of birds’-eye views of my back yard, and see if you think I put the beds in roughly the right place:

Looks pretty good, doesn’t it?  You might even say that the location doesn’t much matter, because you’re going to get the same number of hours of sunlight almost anywhere in that back yard, regardless.  What’s shaded in the morning will be sunny in the afternoon, and vice-versa.

Problem is, an hour of sun is not an hour of sun.  Sunlight is much stronger around solar noon, and is weaker the farther you are from noon.  And, because the sun is due south at noon (in the Northern hemisphere), you have to know which direction is south, in order to judge what part of the yard gets the most solar energy.

Source:  Curtonics.com

You need to figure out the locations in your yard that place due south directly between those lines of trees.  Those locations get the greatest amount of high-intensity, near-noon sunlight.

To cut to the chase, you need to calculate where your potential garden site is, relative to the obstructing trees, and to due south.  The sunniest locations in the yard will have these two properties.

  • Due south (180 degrees) bisects the angle from your location to each side of obstructing trees.  E.g., find a spot where the bearing to one set of trees is 150 degrees (180 – 30), and the bearing to the other set of trees is 210 degrees (180 + 30).  That is, you get equal hours of morning and afternoon sun.
  • The angle from your location, to the obstructing trees, is as wide as possible.  For example, the location with a 60 degree spread above will get more total sunlight than a location with a 40 degree spread.   That is, you get as many total hours of sun as possible.

So now, take a look at my back yard, oriented so that south is directly down.  Do you want to change your prior answer?  By the look of the shadows, this is about 11 AM solar time.  Note that the left edge of the yard is already in sunlight.

 


Skirting a couple of pitfalls.

Let me take a brief break to mention a couple of pitfalls that can mess up your attempts to locate your garden in the sunniest spot on the yard.

Daylight savings time.  Man I hate having to get up at 2 AM to turn all the clocks forward, as required by law.  But the upshot is that solar noon occurs around 1 PM during daylight savings time.  For example, on the hourly insolation graph above, peak insolation occurs around 13:00, or 1 PM.  That’s not a mistake, that’s just daylight savings time.  So if it’s summer, and you look to see where the shadows fall at noon, you’re screwing up.  Because noon, daylight savings time, is actually 11 AM solar time.

Above:  Compass set up for 10 degrees west magnetic declination

Magnetic declination.  Declination is the extent to which magnetic north — where the compass needle points — deviates from true north.  Because of magnetic declination, you can’t simply use the raw readings from a standard magnetic compass in order to locate your garden in the right spot.

If you have a compass made for use on land, and it’s anything but the most basic compass, chances are you can adjust the compass to account for declination.

You can find the magnetic declination for your locality at the US Geological Survey, among other places. Currently, magnetic declination at Vienna VA is about 10 degrees west.  That means that the compass needle actually points to a heading of about 350 degrees, not 360 degrees (true north).  That’s about 2.5 degrees further west than when I was a kid in the 1970s.

Magnetic declination is one of those incredibly simple topics that always manages to get an incredibly opaque explanation.  But as long as you have a compass that can be set to account for your local declination, it’s really simple.  The picture above shows a compass set up for 10 degrees west declination.  Despite the fuzziness of the photo, I think it’s obvious that the compass body has been offset 10 degrees relative to the degree ring.  When the needle points to 350 degrees (10 degrees west of true north), 360 or 0 on the degree ring shows you true north.


The sunniest spots in my back yard are directly next to the trees.

I can now take Google Earth, and start drawing in the angles between various backyard locations, and the ends of the lines of shading trees at the sides of the yard.  It’s a little crude, but the conclusion is inescapable.  I put the temporary beds too close to the middle of the yard.  For the most solar energy possible, they ought to be almost under the trees at the side of the yard.  Like so:

Which, to be honest, I would not have guessed, just eyeballing it.

Over the coming weekend, I’ll set up a stop-motion camera to film my back yard for one sunny day.  With that, I should be able to validate that the area that gets the most solar energy is the one outlined.  And I should be able to determine just how much energy I lose if I move away from that optimum spot.

Post G23-005: Wacky weather? No, just seems that way.

 

With last night’s frost, and this afternoon’s snowstorm, I’m trying to think back to the last time we had an 80 degree (F) day. 

Oh, yeah — day before yesterday.

Which got me to asking whether this most-recent temperature swing was unusual.  At Dulles Airport, they went from a high of 80F on Thursday afternoon, to a low of 27F on Friday night.   Or just over 50F swing over the course of two days.

As it turns out, that’s perfectly normal.  Below I’ve plotted the biggest two-day temperature swing, by year, at Dulles, through 2022.

Source:  Analysis of NOAA data, downloaded via https://www.ncdc.noaa.gov/cdo-web/

As you can plainly see, at least one event of this size seems to happen more-or-less every year.  The upshot is that in this part of the country, going from shorts one day to winter coat the next (or vice-versa) does not count as a particularly unusual weather event.

Post G23-004: Garden plan, 2023, step 2: When you come to a fork in the road, take it.

 

People say the ancients constructed their calendars to keep track of religious holidays, based on astronomical events.  Possibly true.  But a nice side benefit of their religion is that it gave them a clear idea of when to plant their crops in the spring.

In the modern world, of course, we eschew such religion-based planting rituals.  Thus my potatoes will go in the ground on St. Patrick’s day, and no sooner.  Because that’s Science.

If left to my own devices, I would undoubtedly plant too early.  Hence the need for my quasi-religious planting ritual.  Here in Vienna VA, today’s high is expected to be near 80.  Which definitely gets me in a gardening frame of mind.  But tomorrow’s low is well below freezing.  We’re still six weeks from our likely last-frost date.

Without getting into whys and wherefores of our ever-wackier weather, this post  presents my vegetable garden plan for the year.  It takes the form of three questions:

  • Why?
  • What?
  • How?

A brief recap

I started my current round of gardening in order to have something to do during the pit of the COVID-19 pandemic.  If nothing else, shoveling around a few tons of dirt to create raised beds provided much-needed exercise (Post G05).

Many people did the same, leading to shortages of everything gardening-related in 2020.  Starting with empty seed racks at my local hardware stores (Post #G02, April 21, 2020) and ending with a long-lasting shortage of canning jar lids (Post #G21, August 2020).

Gardening was a much nicer experience then than now.  The cessation of much local and long-distance travel meant that the air was cleaner, the skies were blue-er (Post #614, Post #618) , and neighborhoods were a lot quieter.  So quiet I could hear the hum of the bees at work in the garden (Post #G11), a sound I have not heard since.  A big bed of sunflowers, just outside my bedroom window, provided much-needed cheer during what was otherwise a fairly dark time.

But now, the air once again stinks of diesel exhaust, the Northern Virginia summer sky has returned to its traditional smog-white, the constant noise of traffic and construction smothers sound of the bees, and gyms are open for business.

In other words, things are back to normal.


1:  Why?  It’s now my hobby.

When I distill it down, I’m going to continue to garden for four reasons.

One, it gives me a physical activity that actually has a purpose.  Sure, I can go to the gym, and get exercise for exercise’s sake.  I can walk around the neighborhood, for the sake of walking around the neighborhood.  Gardening is a way to get non-pointless exercise.

Two, I really like growing plants.  I guess I can come out and say that.  Mostly food.  But flowers are OK, in moderation.

Third, I’m cheap.  As hobbies go, annual costs don’t get much cheaper than a few pounds of potatoes and a few packets of seeds.  I’m not convinced that my gardening pays for itself in the value of produce.  But the fact that I get anything at all useful out of a hobby is a bonus in and of itself.

Finally, it leaves nothing permanent.  What isn’t eaten turns to compost.  So, unlike (say) woodworking, this doesn’t produce yet-more-clutter, during a period of my life when I’m doing my best to get rid of stuff


2:  What? Only stuff we like to eat.

In an intellectual breakthrough this year, I’ve decided on the following guidelines:

  1. Only plant stuff that we actually like to eat.
  2. Don’t plant stuff that the deer like to eat
  3. Don’t  plant stuff that the bugs like to eat.
  4. Don’t plant stuff susceptible to diseases common in my garden.

Being the kind of guy I am, I of course formalized that with a spreadsheet.  But it doesn’t tell me anything I didn’t already know.

Yellow:  Certain herbs and herb-like plants rank highly here because they are extremely easy to grow, take up little room and cost an arm and a leg at the store.  So, dill and rosemary, which I already grow, and ginger and turmeric, which are apparently easy to grow from grocery-store-purchased product.

Light blue:  Potatoes, sweet potatoes, and winter squash. These all provide a lot of calories per square foot and (so far) have been both extremely easy to grow and highly productive in my garden.  Plus, we like to eat them.

Red:  Tomatoes and sweet peppers.  Easy to grow, we like to eat them.  Say no more.

Dark blue:  The entire garlic and onion clan.  I’ve had such spotty luck with these over the years, I’m going to skip them this year.  Plus, my yields have been lousy.

Green:  Peas, beans, lettuce, okra.  We like to eat them just fine, but all require significant fuss.  And, except for green beans, in a good year, yields are modest at best.  But peas and lettuce can go in when it’s cold, and my wife likes green beans.  So these are definitely going to get planted.  Some.  Not a lot.

Purple:  Cucumbers and summer squash.  I’ve had such a bad time with insect pests that I’m skipping those this year.


3:  How?  When you come to a fork in the road, take it.

After three years in the Virginia climate, my temporary raised beds are “showing their age”.  Which is a nice way of saying “falling apart”.  I put up a set of temporary raised beds during the pandemic, recycling some yard signs, bamboo, and other materials around the yard.  Their temporary nature is now showing pretty badly.

I did that to minimize my investment.  I figured that if gardening didn’t work out, I could just tear them apart, spread the dirt on the low spots on the lawn, and plant grass.  Nothing wasted.  Nothing headed for the landfill that wasn’t already headed there before I tried gardening.

So I’ve reached a fork in the road.  Either I do what I had planned on originally, take the beds down, use the dirt to even out the lawn, and be done with gardening.  Or kick it up a notch.

Separately, things snowballed beyond the mere construction of the beds.  In addition to the beds, I now have irrigation line, various types of row cover and insect netting, trellising material, tomato cages, deer deterrent devices, and so on.  Not a huge dollar investment, as these things go.  But it’s a lot of stuff that serves no purpose outside of gardening.

The upshot is that I’m now going to go back and do this right.   But only as a last resort.  The patchwork of temporary beds of varying depths, oriented along the low spots of the lawn, will be replaced by a single long bed oriented east-west, with a permanent trellis along the back.  This will simplify everything from irrigation to protection against deer, and dovetail with the remaining in-ground beds that are now devoted to cane fruits.

I quite like the coroplast (yard sign) sides, and as I have several long sheets of that around, the new bed is going to be coroplast-and-post as well.  I see no reason to import materials if I have durable materials on hand that would otherwise be trash.

As an extra added bonus, this allows me to re-shovel the multiple tons of dirt that I ordered in the first place.  Much better than wasting my time at the gym.  And see how my hugelculture experiment turned out.  There are trash pieces of wood at the bottoms of all these beds, and I’ll get to see what happened to them after three years in the soil.

The goal is to have a single, well-constructed bed of uniform depth, with trellising, deer protection, and irrigation built in.  We’ll see how close I come to that ideal.


 Conclusion

After three years of seat-of-the-pants gardening in temporary raised beds, I have reached a fork in the road.  I’m going to take what I learned in the past three years, and move forward with a single permanent bed incorporating everything I think I need to grow a bit of vegetables and flowers in my back yard.  And at that point, I’ll focus on a few things that we really like to eat fresh out of the garden and that seem to grow well in this climate.  And hope for the best.

Post #1714: Ah, crap, another 80 MPG trip.

 

I am presently recovering from a severe shoulder sprain.

It was self-inflicted, the result of patting myself on the back too hard.

The problem starts with my wife’s Prius Prime.  It has more-than-met our expectations in every respect.  In particular, as-driven, it typically exceeds the EPA mileage rating, either on gas or electricity.

Lately, I’ve been trying a few techniques to try to squeeze some extra gas mileage out of the car.  Just some around-town trips, driving it to try to keep the gas engine in its most efficient zone.  Which, per Post #1711,  boiled down to fast starts on gasoline, followed by coasting on electricity.  Below, that’s an attempt to stay on the top of the green efficiency “hill”, followed by keeping the gas engine off while driving in the aqua “EV carve out” zone.  (The labels on the contour lines are “efficiency”, the percent of the energy in the gasoline that is convert to motion.)

Results were encouraging.  A couple of test trials showed mid-70-MPG for a series of trips and test runs, entirely on gasoline (using no grid electricity).  Given that the car has an EPA rating of 55 MPG for city driving, I figured I was doing something right.

But at some point, it dawned on me that

  1. the current EPA mileage test is based on the typical U.S. driver (i.e., somebody who drives like a bat out of hell, whenever possible), and
  2. I have no idea what my “typical” city mileage is, because I almost never drive the car, around town, on gasoline.

In short, I made a classic mistake of trying to do an experiment without a control.  I had no baseline to which I could compare my results.  I literally didn’t know what mileage the car would get if I wasn’t fooling around with the accelerator pedal.

I decided to find out.  Yesterday we took a trip out to my sister-in-law’s and back.  About 15 miles, mostly on 35 MPH suburban roads, rolling hills, no traffic to speak of.  Gas only.  Didn’t need the AC or the heat.  Relatively few stop lights.  Driving normally.  (But acknowledging that I’m a light-footed driver by nature, and that monitoring the car via a Scangauge 3 has done nothing but increase that tendency.)

In short, reasonably close to ideal conditions for a trip.

Results:  The odometer clicked over to 80 MPG for the trip, just as we were returning to our driveway.

I am reminded of the following medical advice:  If untreated, the common cold will last a week.  But with proper medical attention, you can expect a full recovery in just seven days.

Thus it would appear, for urban hypermiling in a Prius Prime.  As-driven, 80 MPG, for my suburban area.  No fancy footwork required.

Post #1713: Norfolk Southern Accident History

 

As we all know by now, the cause for the recent Ohio train derailment was traced to an overheated, failed wheel bearing, per the National Transportation Safety Board.

Sounds like a random equipment failure that, in this case, had some bad consequences.

But isn’t that just part of a much larger pattern of neglect, leading to an ever-increasing rate of train derailments?

No.  And that’s easy to say, because, of course the Feds track this.  Of course you can access it.  You just need to bother to look.

From the Federal Railroad Administration, Office of Safety Analysis, Ten-year query form.  Data for 2022 are preliminary through November.

Norfolk Southern’s rate of derailments has been more-or-less the same over the past two decades.  Same for accidents involving hazardous materials.

Obviously, facts cannot possibly compete with the angertainment-fest that has become our national news reporting.  As evidenced by the comments sections on newspaper articles.

But on the off chance that you might have been wondering about this, the answer is no.  For Norfolk Southern, the rate of accidents of this type is about what it has been for the past twenty years.

Post #1712: The Balkanization of EV battery recycling

 

Background:  I can’t get rid of the damned thing.

My wife and I have been believers in electrically-powered transport for some time now.

In 2008, we bought an aftermarket battery pack to convert my wife’s 2005 Prius into a plug-in hybrid electric vehicle.  At the time, the manufacturer (A123 systems) assured us that the battery pack would be fully recyclable, and that they had partnered with Toxco, Inc. to guarantee that.

To be honest, that retrofit never worked very well.  It wasn’t the battery’s fault.  The main limitation was that a Prius of that generation wasn’t really built to function as an electric vehicle.  That placed a lot of limitations in driving in all-electric (“EV”) mode.  Gasoline savings were modest, at best.

Fast-forward to 2012.  A123 had gone bankrupt.  Toxco was no longer in the battery recycling business.  We had a problem with the charger on that battery pack, and decided to have it fixed, in large part because, at that time, there was no way to get rid of the damned thing.  Far less hassle to fix it and keep using it.

At that time, the word was that infrastructure for EV battery recycling was just around the corner.  But from a practical perspective, here in Virginia, we couldn’t find someone to take that off our hands and recycle it.

Fast forward to 2018, and the original nickel-metal-hydride traction battery in that Prius died.  We thought about scrapping the car at that point (177K miles), but everything else was fine, we dreaded the thought of buying a new car.  So we we paid to have the dealer install a new Toyota nickel-metal-hydride (NiMH) traction battery.  (Toyota recycles the dead NiMH batteries recovered through their dealerships.)   But, in part, the decision to keep the car was driven by that A123 battery pack.  We looked around for recyclers, but there was still no way to get rid of the damned thing.

Apparently, EV battery recycling was still just around the corner.

Jump to 2023.  It now looks like that 15-year-old A123 pack has finally given up the ghost.  It will no longer charge.  And at this point, we have no interest in trying to get it fixed, even if we could.  Any money spent on that would be better invested in getting a new purpose-built PHEV, such as a Prius Prime.

I’m sure you’ve guessed the punchline.   I just looked around for recyclers, and yet again, there is even still no way to get rid of the damned thing.

Now, that’s not 100% true.  There’s an on-line ad for a company that, if I give them all my information, might be willing to offer me a quote on how much they’ll charge to recycle my particular battery.  There might be a shop as close as North Carolina that might take it, if I could prepare it properly.  I haven’t bothered to inquire.  My wife’s going to call the dealer who installed it originally, after this three-day weekend, and see if they’ll remove it and dispose of it for us.  (Last time we asked, that wasn’t an option.)

My point is there’s no place within, say, 200 miles, that I can just call up, make and appointment, and drop off the battery for recycling.  It’s all either a custom, one-off service, or requires crating and shipping the battery, or required driving at least hundreds of miles, round-trip, if I can find a place that will take it.

On the plus side, I’m in no hurry.  A fully-discharged lithium-ion battery isn’t a fire hazard.  I’ve checked several sources on that, and that’s the overwhelming consensus.  A completely discharged lithium-ion battery is just dead weight, not a death trap.  You definitely don’t want to try to recharge one and power it up, once it has been over-discharged, as it can easily form internal short-circuits in an over-discharged state.  That can lead to a big problem in a short amount of time.  (And chargers in general will not allow you to try to charge a lithium-ion battery with excessively low starting voltage, for exactly this reason.)  But as long as you don’t do anything stupid — don’t bypass the charger, don’t puncture it, don’t roast it — it’ll remain intert.

On the minus side, it looks like the U.S. EV battery recycling industry is in no hurry, either.  I sure don’t perceive a lot of forward motion since the last time I looked at this.  Worse, what seems to be happening is that the industry is going to get split up along manufacturer lines.  Tesla will recycle Tesla batteries, Toyota will recycle Toyota batteries.  And if you fall into the cracks — with some off-brand battery — there will still be no way to get rid of the damned thing.


My impressions of the EV battery recycling market

I’ve been tracking this market for more than a decade now.  With the personal stake described above.  I thought I might take a minute to offer my observations.  In an unscientific way, without citation as to source.

First, it doesn’t pay to recycle these.  At least, not yet.  That was surely true a decade ago, and my reading of is that it’s still true.  So you’ll see people talk about the tons of materials saved, for ongoing operations.  But I don’t think you’ll hear anybody say what a cash cow lithium battery recycling is.

Second, EV battery recyclers start up and fail at an astonishing rate.  Near as I can tell, none of the companies involved in it, when I looked back in 2012, are still in that business.  I just looked up a current list of companies that cooperate with GM dealers for EV battery recycling, and all the names were new to me.  This “churning” of the industry has been fairly widely noted by industry observers.

Third, we’re still just around that damned corner.  The Biden infrastructure bill appears to have about a third of a billion dollars earmarked for development of EV battery recycling (source).

But surely you realize what that means.  See “First” above.  The fact that the Feds have to subsidize EV battery recycling is pretty much proof that it just doesn’t pay to recycle these big lithium-ion EV batteries.  At least not yet.

Finally, car markers are developing their own captive recyclers, for their own batteries.  Tesla has its own systems.  GM has contracts with a limited number of vendors, plausibly to serve GM dealerships.  Toyota has its own system, for batteries recovered by its dealerships.

That last move makes perfect sense.  Because recycling is a net cost, and yet a significant consumer concern, manufacturers are pledging to take care of their batteries, if they are recycled via their dealers.  But, so far, I’m not seeing any generic recycling capability for (say) any hybrid or EV showing up at a junkyard.  Let alone for my oddball A123 batteries.

Per this article, it currently costs Tesla more than $4 per pound to recycle its lithium-ion batteries.  At that cost, you can see why they might be willing to deal with their own, but they’re sure not going to take anybody else’s batteries for recycling.  It’s not clear that other processes — with less complete recycling of all the materials — are as costly as Tesla’s.  As of 2021, at least one company was in the business of simply warehousing used EV batteries on behalf of vehicle manufacturers, handing batteries replaced under warranty.   The theory is that right now, it’s cheaper to store them and hope for lower recycling costs down the road (reference).

I’m sure that big junkyards and scrap yards have some way of dealing with these, at some cost.  Surely plenty of the (e.g.) Generation 3 Toyota Prius hybrids with lithium-ion batteries have now been scrapped.  I don’t know if they can recycle via Toyota’s internal system, or if … well, I just don’t know.


Conclusion

All I know, at present, is that if I can recycle that totally dead 5 KWH A123 lithium-ion battery pack, it’s going to be either a hassle or a major expense or both.  As long as I can get it recycled, I will.

But, the fact is, until that 2005 Prius actually dies, I won’t have to face up to it.

And, in a nutshell, that characterizes the American market for lithium-ion EV battery recycling.

I’ve decided just to let that dead battery be, and let the 2005 Prius continue to haul around that 300 extra pounds of dead weight.

Because, as we all know, readily-available EV battery recycling is just around the corner.