omenti

three dog nights and a changing world

My father never had the thermostat above 60°F and 55° was a more common setting,. At night it would be dropped to 50°.  The house was well insulated and the furnace didn't come on that often if it was above freezing.  During colder weather we spent most of our time in an insulated room in the basement.  We had a lot of sweaters, thick socks, and scarves.

 

Great Falls, Montana lies just East of the Rocky Mountains.  It can be much colder than its latitude suggests as cold arctic air can plunge Southward unimpeded along the Eastern slope of the Rockies.  Global warming has changed the climate a bit, but thirty years ago -40° (F or C) would happen every few years and long spells with high temperatures staying below 0°F are not uncommon these days.   It also happens to be very windy. The residents are became very good at adapting to the climate. 

 

Our house was small so I slept in a small travel trailer most of the time during my high school years. The only real insulation in the Winter was snow..  There were a lot of blankets, a down sleeping bag, a beagle and two silky terriers.  The dogs would make their own beds down to about 40°.  Below that they'd join me in the sleeping bag.   The only down side from these three dog nights was when the beagle had gas.  The sleeping arrangement was always toasty.

 

Another bit of information comes from David MacKay.  Staring in the mid 1960s someone at Cambridge interested in residential heat transport in homes put recording thermometers in a number of homes in town as well as a few other locations around England. The standard Winter daytime temperature was remarkably consistent - about 55° through the 70s.  By 2000 it had crept to 62°. Lower readings than Americans expect, but the Brits may dress more practically.    It would be interesting looking at the insulation value of standard wardrobes over time.  I suspect the emergence of low cost clothing is partly to blame.

 

Over-reliance on Russian natural gas is presenting an enormous problem in some European counties. Short term solutions other than conservation are non-existent, but conservation holds a lot of promise.  Heat people rather than spaces.  A few days ago Jheri wrote noting she's working on warm Winter clothing lines for German and Nordic markets on speculation that natural gas will be rationed for a few years.   The savings projections I've seen involve thermostat settings of 16°C (61°F) .. I know from experience you can go much lower and be perfectly comfortable.  (That said I don't know how some of the high school girls survived with miniskirts back in the day.)

 

In the medium term there are a number of things that can be done, but I struggle coming up with anything at the home level approaching the impact of serious conservation.  The same goes for petroleum usage. Infrastructure changes to encourage cycling can have a non-trivial impact.  Fortunately a few locations (Denmark and the Netherlands)  have made, or are making (Paris), great headway. 

 

The medium and long term will be dominated by power generation and distribution, but progress can and should be made with "smart" heating and cooling along with smart fabrics.   There's much to say about those areas, but for later.

 

Who knows.. maybe tech can be more meaningful than social media and blockchains..  

 

Who knows.

 

 

 

the utility of a color-coded battery

There have been predictions of a hydrogen economy for decades.  At first glance it seems like the ideal fuel.  Its specific energy - how much energy you get from a kilogram - is three times higher than gasoline.  And the byproducts of combustion with oxygen are heat and water.   So why hasn't it happened?  It turns out you should think of hydrogen as more of a battery than a fuel.

 

Hydrogen is the most common element in the Universe and common on the surface of the Earth.  Unfortunately the kind we need, molecular hydrogen H₂ , is very rare.  The only practical way to get it is to use a lot of energy to break down more complex molecules.  Methane is the most common, but other hydrocarbons like coal are used.  The process uses more energy than burning hydrogen releases and usually produces a lot of carbon dioxide and other waste products.  

 

There are many industrial uses of hydrogen, but the fossil fuel industry has been interested in expanding to new markets like transportation and heating.  They have the knowhow - all they need to do is scale their operations.  In fact they've been lobbying governments since the 80s and billions of government money have been spent investigating a fossil fuel driven hydrogen economy.   A good fraction of the funding went into the development of practical automotive fuel cells  - more on that later.

 

In grade school you probably used a battery and two wires to make a simple electrolysis machine that broke water into hydrogen and oxygen gas.  These days the best electrolyzers are something over 70% efficient.  Sounds great but there's another problem.  The energy per unit volume (energy density) of hydrogen gas at atmospheric pressure is about 2,800 times lower than gasoline.  A gas tank for a car would be bus sized.  The trick is to compress or liquify it.   Compressed hydrogen has about one seventh the amount of energy as the same volume of gasoline.  Liquid hydrogen is closer to a third.  Larger, heavier and more expensive than gas tanks, but more practical than attaching a blimp to your car.

 

A hydrogen fuel cell uses hydrogen and oxygen to produce electricity and water. The efficiency of a fuel cell running an electric motor is higher than that of an internal combustion engine so the hydrogen tank is small enough to fit in a car.   Before you can fuel the car the hydrogen needs to be compressed or liquified, both of which take a lot of energy.   About a third of the energy produced as electricity where electrolysis takes place makes it to the tank.  From there you about half of that getting it though the fuel cells and motor to the wheels.   But with the right power source it can be carbon-free.  Unfortunately most of the hydrogen cars to date use a dirtier hydrogen.  And that brings up a marketing term:  the color of hydrogen.

 

Green hydrogen is produced by electrolysis using electricity from a zero carbon source.  Brown hydrogen is produced from methane and black hydrogen from coal (much of the industrial hydrogen in Germany and China is black) Both forms have serious production carbon emissions that, when used in a hydrogen car, emit more than a conventional car.  Blue hydrogen is an attempt to deal with brown and black carbon emission problem.  It't still produced from methane or coal, but the carbon is captured and stored.  I consider that something of a pipe dream, but Japan is interested in blue hydrogen produced in Australia.¹  

 

Hydrogen is frequently mentioned as the future for low carbon airplanes.  Liquid hydrogen would be necessary and huge tanks would be needed.  There are several designs on the drawing board that couild happen in  fifteen years using turbofans designed to burn hydrogen.  They'd still produce some pollution (NO_x) from the heat of combustion and the extra water vapor would leave thicker contrails.²

 

Recent geopolitical issues have raised the issue of using hydrogen to heat homes and businesses rather than natural gas.. after all .. there's a large and very expensive infrastructure in place already.  Countries like England are experimenting with hydrogen/natural gas mixtures. You can get away with as much as 20% hydrogen and use the same furnace burners and conventional pipe infrastructure. In the UK new furnaces will have to have a dual fuel mode - natural gas or hydrogen.   An infrastructure problem is it takes about three times as much energy to move equivalent amount of hydrogen as methane. Also current pipelines may be too brittle over time.  Hydrogen leaks much more easily than methane (which is already a problem) and hydrogen leakage is an indirect greenhouse gas.  There are a lot of potentially expensive questions to answer, so I wouldn't pencil this in as a slam dunk.  On top of it you need to produce about three times as much energy to heat a house with hydrogen as you would with just electricity.  Use a heat pump and electric heating looks even better.

 

Hydrogen could be used store power for the grid, but that gets into comparing many forms of energy storage, so not now.

 

My gut tells me hydrogen could see niche applications..  Long distance trucking if battery development plateaus  soon (I wouldn't bet on that, but I wouldn't want to be a truck manufacturer) and aviation in the long term (15 years at the earliest).  

 

But a final comment - if you have enough it will gravitationally collapse and fusion ignites - you have a star.  We happen to have one.  The trick is just one of collection.  So in that sense life on Earth and almost everything we do is part of an hydrogen economy, but the convertor is about 150 million kilometers away.

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¹ Japan is big on hydrogen and had originally envisioned scaling up nuclear power, but that pathdied with a tidal wave.)  At this point I think blue hydrogen has underpants gnome issues.

² Contrails appear to be serious global warming issues.   It's possible that leaving them at night doesn't make sense and flights may have to occur at lower altitudes - say 20,000 feet rather than over 30,000.  That would mean slower speeds which means propellers may be practical so liquid hydrogen powering fuel cells to run electric motors may make sense.

 

 

what's in a name?

Surrounded by dramatic peaks on a narrow road etched into the side of the mountains you drop into forested area that continues into a string of foothills.  It's clear and you wish you were on your bike this time around.  The trees thin out and suddenly it's upon you.  You're at the summit of the last foothill and the expanse of the prairie opens up ahead.  Off in the distance is a short mountain range, but mostly it's prairie and you need to catch your breath.

 

Oceans and mountains have their appeal, but so does the prairie.  I suspect Montana Jeri and Alberta Jheri know this too. More than a few people from the area are taken by the outdoors. You find a number of artists, photographers, as well as people who are taken to learn about their surroundings.  I feel hard for the sky and have yet to recover.

 

The area is positioned such that auroras aren't uncommon during solar maximums.  Alberta and Saskatchewan have groups of serious amateur aurora watchers.   About ten years ago they realized something was different.  Something more frequent than garden variety auroras with a different color (they'd say colour) and shape.  Early spectrographic measurements revealed it was a thermal emission rather than the distinct colors of excited atoms dropping to lower energy levels.  

 

Serious work using satellites and the rich ground-based observations of the Canadian amateurs began around 2016.  It was real and not an aurora.  It needed a name.    One based on a children's movie turned out to be perfect.

 

The backronym Strong Thermal Emission Velocity Enhancement nicely suggests STEVE.

 

 

Much more is known now and the name remains.  The past week has been some beautiful displays along the Canadian Rockies.  I say them as a teenager and then again in my 30s, but didn't realize they weren't auroras.   Cheers to those curious enough to ask the questions.

 

great news! maybe the best model of how physics works is broken!

Then again it could be another false alarm.  Sometime about the W boson being too heavy.  I'll try and give a bit of background.

 

The best model of the universe - everything but gravity - is called the Standard Model. It unifies electro-magnetism, the weak force and the strong force - three of the four fundamental forces of Nature.¹   There are 17 fundamental particles (a physicist would say fields, but I'll use particles here).  The matter we see every day is built of a class of particles known as fermions.  Six quarks and six leptons. Protons and neutrons are made of two kinds of quarks and the electron is one of the leptons.  The remaining five are in a category known as bosons and are responsible for three of the four fundamental forces.  Gluons are associated with the strong force and bind quarks.  The weak force is carried by W and Z bosons and is responsible for radioactive decay and the process that makes the Sun shine.   The electromagnetic force is carried by the photon. Electricity, magnetism and the reason you don't fall through the floor.   And the Higgs boson gives the other particles mass (crudely speaking).  

 

All of this came together in the mid 70s with experiments confirming the Standard Model to higher and higher levels of confidence.  There were a few  suspicious corners, but none were showstoppers.  Until now. (maybe)

 

So what's not to love?

 

It's incomplete.  The matter I've described  - the stuff we're all made of and all of the exotic particles we're found - all of that represents a bit less than five percent of the mass-energy of the Universe.   Next to nothing is known about the remaining 95 percent!  That's a bit of a problem.  And no one has been found cleanly addresses all four forces.  

 

What scientists love to do is discover something.  Something completely new and out of the blue or perhaps overturning an accepted theory.²  That's what may have happened.  The W boson - a particle responsible for the weak force - is a very heavy and short-lived particle.  It's been carefully studied and a very careful experimental work at CERN gave us its mass.  This week the results of another very careful measurement using a different approach at FermiLab were announced.  Fermilab finds the mass is about a tenth of a percent higher.  Both measurements are so careful that the chance that that they're really the same is less than one part in thirty million..

 

It may be the CERN results are wrong and/or the Fermilab results are wrong.  Hundreds of people will be spending a lot of time reanalyzing data and checking that all of the steps along the way.  But maybe, just maybe there's new physics!  

 

Soon CERN will be taking data again after a three year long upgrade.  New measurements will be made that could settle the matter.  One of the explanations could be a fifth force of nature that is so subtle that it is only showing up here.  

 

There is real excitement although it will be several years before anything conclusive is known.  I have to add that my gut tells me there's probably a subtle bias, but my heart is hoping Fermilab is right.

 

But why?  I think there's something to fundamental curiosity.  The track record for generating useful spinoff is remarkable.  A few estimates place medical spinoff from high energy and nuclear physics in excess of twenty dollars for every dollar spent.  Of course there are issues with how long it takes, but some of you may owe your lives to these developments. 

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¹ So far no one has been able to cleanly add gravitation, but for calculations you usually consider it separately.  Something informally called Core Theory is the Standard Model with Gravitation tacked on separately.  

² In physics theory takes on a special meaning.  It's a hypothesis that has been rigorously tested to the point where it's accepted as the best description by the community.  It's a very high bar.