Post #1852: The USDA says to #leavetheleaves.

 

No less an authority than the USDA is now on the bandwagon for #leavetheleavesThat is, the idea that gathering and disposing of fallen autumn leaves is foolish from an environmental standpoint.

The conspiracy-minded among you may view this as just another facet of the Deep State, an evil cabal within the U.S. Civil Service determined to disrupt every facet of the American Way.  Yes, stooping so low as to attack that most harmless of small-town fall rituals … 

requesting that citizens rake/blow leaves to the curb, so the Town can repeatedly drive its high-decibel fleet of dedicated leaf-vacuuming equipment through town, and so spend hundreds of thousands of dollars to suck up those leaves, then trucking hundreds of tons of leaves down the interstate so that they can be sterilized via hot composting at some remote location, ensuring that no offspring of this year’s crop of butterflies and similar insects survive.

Well, at least, that’s the tradition in my small town.  It’s an industrial-scale process that’s a far cry from Normal Rockwell, if you get my drift.

Source:  Pinterest.

The USDA is just the most recent in a long line of organizations that have gotten behind the idea that leaf collection and disposal of this type is a relic of the past.  Historically, in this area, it’s the immediate successor to the era in which suburbanites routinely raked up and burned fall leaves.  Before that was banned owing to the resulting air pollution.

Locally, even the surrounding county (Fairfax County, VA) has proposed to stop doing vacuum leaf collection (see Post #1821).  In part, because that turned out to be a real hassle for county staff this past year.  But also for all the good reasons outlined on the USDA web page.

But in Vienna, VA, traditions die hard, unless there’s some profit to be made in killing them.  And new learning percolates excruciatingly slowly.  Town-wide, this is mostly about doing our bit to slow the insect apocalypse (reference National Academies of Science).  Not sure that matters to most residents, even though it should, from a survival-of-our-species standpoint.  All said and done, it’s still an open question as to whether we can break ourselves of this 40-year-old tradition.  Just to benefit a bunch of butterflies and such.

My prior screeds on this subject include:

  • Post 1822, on the fuel used in this process.
  • Post 1821, on Fairfax County staff recommending no leaf vacuuming.
  • Post 1612, on the emissions from gas versus electric leaf blowers.
  • Post G22-034, on vacuum leaf collection being a relic of the past.
  • Post 1463, on putting the environment first in the Town’s decision-making.

This, in addition to several posts on the economics of the Town of Vienna’s centralized leaf collection and disposal process.

 

Pictures in this post are mainly from Gencraft.com and Freepik AI

Post #1851: Who put the weather on fast-forward? Tropical storm Ophelia.

 

Tonight and tomorrow, it’s going to rain like crazy around here.  In the DC area, we’re expecting to get about three inches, with some significant probability of tropic storm force winds (sustained winds in excess of 39 MPH).  My brother lives in the Tidewater area, and he’s right on the edge of the region where four to six inches of rain are expected.  Along with maybe a four foot tidal surge.  All from tropical storm Ophelia.

What I find odd about is that the very first mention of this disturbance was late yesterday morning.  That’s based on a check of the archives at the the National Hurricane Center.  The very first mention of Ophelia — the point at which it became a named tropical storm — was the forecast update as of late afternoon today.

Source:  National Hurricane Center.

In short, the interval between this thing becoming a name tropical storm, and the start of the deluge, here in NoVA, is maybe eight hours.  Plus or minus. Even worse, my brother in the Tidewater area got about 6 hours’ warning between the time Ophelia became a named storm, and the time that tropical-storm-force winds are expected to hit his area.

I don’t think the weather used to work this way.  Either that, or my memory has become so clouded that I don’t recall the times this has occurred in the past.

I used to have a sailboat, down in Tidewater Virginia, a couple of hours’ drive from where I live.  I spent many autumns tuned into the hurricane forecast for this area, because a major storm meant that I had to move the boat off its dock and moor it in the middle of the river.  (Because, if you don’t, the storm surge floats your boat up and over the dock, at which point wave action destroys both the boat and the dock to which it is tied.  So it’s not optional.  It was written into the contract allowing me to use the dock.)  This, along with everybody else who kept a boat at the same dock.  It was quite a fire drill every time.

My recollection is that major tropical cyclones were well-anticipated events, and that you’re read about them for days before they made landfall.  I’d have plenty of time to gear up, arrange time off work, and get the boat prepped for the oncoming storm.

I further recall that when a few such storms “popped up” in the Gulf of Mexico two years ago, without crossing the Atlantic first, that was news, meteorologically-speaking.

But maybe the short-cycling of tropical storms is now the new normal.  Plausibly, this is brought about by elevated Atlantic Coast sea surface temperatures.  Warm ocean temperatures in the Gulf of Mexico got all the headlines with the most recent hurricane.  But in fact, ocean water temperatures are a few degrees above historical averages all up and down the U.S. East Coast.  And, apparently, a few degrees is all it takes to whirl up a tropical storm in a couple of days, flat.

And so, this went from literally nothing on the weather map, to landfall of a tropical storm, in just about exactly two days.

And, unlike those pop-up tropical depressions of a couple of years back, that doesn’t even seem to be triggering comment this time around.

It’s just the way the world works now.  Having days of warning for a tropical storm landfall?  That’s so last-century.

Get used to it.

All pictures here are from Gencraft.com AI.  We never really did have a meeting of the minds over what I meant by “hurricane”.

Post G23-058: Solar tomato drying fail.

 

A few days back I set up a batch of tomato slices to dry in my tote-based solar food dehydrator.  Without perfect weather, it was a race between sunlight and mold.

Mold won, as shown above.

At the minimum, this convinces me that I need an indirect solar dryer, as described in the just-prior post.  My little plastic-tote dryer just doesn’t have enough power to dry tomatoes in less-than-perfect weather.

The interior of the tote seemed to get pretty hot, in full sunlight.  As in 130F, loaded with just two small trays of tomato slices.  So I’m not quite sure why this failed so badly.

One possibility is lack of direct ventilation of the tomato slices.  I had a computer fan pulling air through this tote.  While that did in fact exhaust the humid air in the tote, there was nothing blowing on the tomatoes to disrupt the  “boundary layer” of air directly adjacent to each tomato slice.  I would then guess that the air directly adjacent to each slice stayed quite humid, thus encouraging mold growth.

A second possibility is the lack of sterilizing UV radiation inside the tote.  I believe the clear Sterilite tote is made of polyethylene, which is a reasonably good absorber of UV radiation.  UV strongly inhibits mold growth, so the presence of warmth without UV was less than ideal.

Yet a third is the level of cloud cover.  Depending on the day and the hour, the summer sky in Virginia can be quite cloudy.  This power-ventilated box is going to cool off pretty rapidly in any extended period of cloud cover.

My bottom line is that if the weather is good enough to use this tote-based direct solar dehydrator, I’d be better off just sun-drying my tomatoes the traditional way.  Lay them on a screen, cover them with netting, and expose them to the breeze and the sunlight.

 

Illustrations in this post are from Gencraft.com and Freepik AI.  The only real picture is the first one, of blackened tomato slices sitting on drying trays.

Post G23-057: Solar food drying, a better understanding

 

Upshot:  Direct solar food drying — putting your food out in the sun (with or without some clear cover) — is an inherently low-powered and slow way to dry food.

By contrast, indirect solar food drying — connecting a solar heat collector to a box full of food to be dried — can be much, much faster.  That’s because you can increase the power of the device.  Mostly, you can greatly increase the efficiency of the solar collector, relative to direct solar drying.  Secondarily, you can also make it larger, if you choose — there’s no necessary relationship between solar collection area and the area covered by food.

And faster drying means lower taxes!!!  Uh, no, I meant, faster drying means fewer days-in-a-row at the mercy of the weather.

The key, to all this new-found wisdom?  Figuring out that a box-with-clear-lidfood dryer is, technically speaking, a flat-plate solar collectorThen realizing that flat-plate is really inefficient, relative to other things I could make.

I need to make an indirect solar food dehydrator.  And it only took me two or three years to figure this out.

In the interest of reducing TL;DR, I’m breaking this into two posts. This post is just the setup.  Next post should be the actual construction and use, if any. Continue reading Post G23-057: Solar food drying, a better understanding

Post G23-053: It’s a beautiful day in the neighborhood.

 

Today feels like a fine autumn day, here in Vienna, VA.  So I thought I’d write something unalloyedly nice.  On the screen porch, feet up, sipping iced tea.

Listening to the katydids sing.  As I type.

Or whatever those damned bugs are.  Maybe the right name is locusts, but locusts get such a bad rap that I’ll cut them some slack and call them something nicer.  You might find that loud chirruping annoying, where you live.  But where I live, the katydids are Nature’s white noise machine.  They mask what would otherwise be unrelenting traffic noise, lawn mowers, leaf blowers, and so on.

I say autumn day, because the air is cool and the humidity is low.  After the heat and humidity of summer, this is a welcome change.  So it feels like fall, even if the autumnal equinox is still almost a month away.

Here are my observations on three nice things that are happening in my garden. Continue reading Post G23-053: It’s a beautiful day in the neighborhood.

Post G23-052: I dried my underwear in my food dehydrator.

 

I know what you’re thinking.  You’re thinking “Hey, dummy, that’s what the microwave is for.”

And while I acknowledge the truthiness of that statement, my excuse is that I baked my briefs in this manner for Science.

This post focuses on a seemingly simple question:  Why is an electric food dehydrator such an incredibly energy-intensive way to preserve food?

The answer is unsatisfying.  In roughly equal parts:

  • Evaporating water is energy-intensive
  • Evaporation water out of food is even more so.
  • My particular dehydrator is somewhat inefficient.

My bottom line is that drying a pound of wet produce, in my electric dryer, under optimal conditions, takes about 2 kilowatt-hours of electricity.  And there ain’t much I can do about that, other than coming up with a solar dryer that will function in my climate.  My first attempt at that turned out mediocre (Post G22-015).

Continue reading Post G23-052: I dried my underwear in my food dehydrator.

Post #1843: Why are ceiling fans vastly more efficient than box fans?

 

In a nutshell?  To provide the same flow (CFM or cubic feet per minute), a small fan (like a box fan) has to move air a lot faster than a larger fan (like a ceiling fan).  And to move air fast, it takes disproportionately more pressure — and hence energy — than it takes to move it slowly.

The rest is just arithmetic.

I’m not talking slightly more efficient.  It’s well-established that ceiling fans are the most efficient type of home fan you can buy (reference).

I’m talking on-order-of five times as efficient as a box fan.  That, comparing the elderly ceiling fans in my house, against the most efficient modern box fan currently sold at Home Depot.

My main point is that the efficiency advantage of ceiling fans is rooted in basic physics.   It’s purely a consequence of their larger size.  It has nothing to do with (e.g.) the grilles on the box fan or the efficiency of various styles of electric motors.  It is simply that to achieve some given rate of air movement (cubic feet/minute), it takes far less energy to move a large volume, slowly, than to move a small volume, quickly.

Not only are ceiling fans more efficient than box fans, they always have been, and always will be.  It’s not the motor, or the housing, or the grille, or any of that.  It’s just physics.

Edit:  This also explains why bathroom fans are so slow at clearing the air.  If you wanted a bathroom fan that could move as much air as a box fan, it would require a 500 watt motor (Post #1859).

 

Continue reading Post #1843: Why are ceiling fans vastly more efficient than box fans?