You would not start form here

There is an international joke which goes something like this: "A sharp dressed man on a horse or car asks a farmer for directions to the big city who replies 'You wouldn't start from here'".  Much the same applies to a sustainable energy economy.

A street gas light (from somewhere posh?)

I recently came across a copy of "Everybody's Pocket Encyclopedia" dated 1891.   Somethings never change and others become irrelevant.  The list of 47 celebrities includes Prince Bismark who unified a number of German states into a single country and gave his name to at least one battleship.  Further down the pages is the actress Lilly Langtry who would have been a gift to today's Celeb magazines.  In the same spirit is a table of the  probability of a woman marrying at a given age and her weight for her height, evidently no such data was available for men.  In contrast there is a somewhat confusing method for estimating sidereal time and local time from longitude which implies the book was carried by people crossing continents (A lot of my family went west to America and East to Australia in the early part of the 20th century).  I'm guessing, but today few people are interested in the correct way to address a bishop.

At the end of the 19th century electricity was coming into general use but gas was a common fuel for lighting and coal provided warmth and the power for industry and transport.  The Encyclopedia's list of economic events is a bit patchy on electricity, for instance there is no reference to Nikola Tesla (who among other things developed the transformer) or to Charles Parson (steam turbines were a good way to turn generators).  However, the it has a few milestones for gas lighting:

• 1780 - The invention of the Argand Burner in Geneva
• 1786 - Lebon's Gas light invented
• 1792 - Murdoch's Gas Lighting Trial
• 1804 - Windor's Gas Patent
• 1807 - Clegg's Gas Works built
• 1813 - Westminster Bridge lit by Gas
• 1815 - Clegg;s Gas meter invented
• 1860 - Hugon's Gas Patent (Gas engine)

These events describe the production, use and commercialization of gas as a fuel.   From 1850, references to electricity become more frequent.  Whilst the displacement of gas lighting started in the latter years of the 19th century, the process did not approach completion until the 1920s, a span of approximately one generation.

There are plenty of fossils from the age of gas.  My own house has the remains of a network of gas pipes which supplied light fittings and geysers.  All this was installed before the advent of "Part P" regulations and some of the notches in the joists are well positioned.  Skips are a good source of social history, when a Victorian property is "gutted" gas pipes are often part of debris.

Edwardian fossils: The wall has a blanked off pipe showing the location of a gas lamp and the grate was part of the house's zoned heating system.

And my point is.....

The acceptance of a "new" technology which does not have to displace an old one, such as mobile phones, can be quite rapid, however, displacement can be a slower process.  In my view, the key technologies for the large scale adoption of sustainable energy sources are storage and management.  This includes devices such as the Tesla "PowerWall" and the internet of things both of which are recent innovations.  Utility scale wind turbines started appearing in the 1980's, solar PV became a mass market technology after 2000.  The table above spans a period of 80 years, these things take time, but if you were starting from scratch......

A very short social history of plumbing

Also, a personal and possibly inaccurate one.  I started last week hunched up over a toilet with my head between the rafters and ended it sitting on the toilet staring at a pressure gauge.  In the intervening week I had seen a century of plumbing and possibly social history.  The renovation of my house has got to the point where some plumbing needs to be dealt with before I can move on.

Lead Piping

The house was built in 1901, at that time a plumber earned about £2 per week or £100 per year and a "professional" e.g. doctor, vicar or solicitor might have received £400 per year.  This is a ratio of 4:1.  Today, plumbers are professionals and the equivalent ratio is 1:1 or less.  Assuming the relative cost of  materials to be the same, the proportion of a job represented by labor has increased.  I dredged these figures from some long forgotten book, so this theory hangs by a very slender thread.

Iron pipe blocked with rust and limescale

When the house was built all the things that used water were clustered together, albeit over two floors.  The piping was lead, bits of it are still embedded in the plaster.  I have never worked with lead but I'm guessing that it's a difficult material.  Whilst it is soft and malleable, it is thick walled and some form of bending tool would be needed to get it round corners and because it is heavy it may have taken two men to install, one to hold it in position and the other to fasten it.  Jointing would require some skill, too much heat from a blow lamp and the stuff would melt or collapse.  I have welded thin sheet metal and know the frustration of letting the work get too hot and watching a hole appear and then grow large.  So I'm guessing that plumbing in 1901 was slow, heavy and skilled work.

A screwed-up fragment of the Daily Mirror from 1949 with the remains of a Jane cartoon strip

Sometime around 1949, an attempt was made to replace some of the lead plumbing with iron piping.  I found a fragment of a "Jane" cartoon from the Daily Mirror dated 1949 which was probably associated with the installation of back boiler in what was then the kitchen.  From 1932 to 1959, Jane was forever saving the nation and losing her clothes with equal frequency, when I worked in a factory in the 1970s old men remembered her with affection/lust.  Iron is not an ideal material for a domestic hot water system, if for no other reason than it rusts. by 1980, much of this pipework was blocked with limescale and rust.  Unlike lead piping which could be bent into position, iron has to be got round corners with threaded elbows.  This required different skills from those needed for lead.  The pipe had to be cut with a hack saw, then each end of the pipe had to be threaded.  Yet again, I'm guessing, but it was probably the apprentice who did the cutting.  A few times in my life I have had to cut up bar stock for some reason or another and I know it to be hard, dull work.  The man who installed the iron pipe was highly skilled as he got it round brickwork and joists in a way that would be hard to do with copper.  It took me a week to remove this pipework.  I used a hole saw to get out the "hidden" lengths which could not be reached with a hack saw, the trick was to drill the pilot hole through the pipe, then use this to guide a hole saw which was half an inch larger than the pipe.

By 1980, the plumbing consisted of lead piping with repairs for frost damage and blocked iron pipe.  The owner decided that enough was enough and had the house re-plumbed with copper pipes.  This would have been a big job and one which I think was "done to a price".  The best routes had been taken by the iron pipes and it was probably cheaper put in 20 metres of copper pipe to take bath water a distance of 7 metres.  The boiler heated the hot water using a gravity feed system which was none to efficient, but all this was better than the original installation.    I have spectacularly made a mess of plumbing using copper pipe, my biggest mistake being not to practice soldering before I started the main job.  These days before I tackle anything big, I find something small to practice on which will either tell me I'm incompetent or teach me how to do it.  With the forgoing caveat, copper piping is reasonably easy to work with, it cuts easily, the fittings are not expensive and solder joints can be made quickly.  As a novice, I tend to use "Yorkshire" fittings which are more expensive than "end feed" but only require even heating with a gas torch.  No one seems to be using lead or iron pipe any more.

Copper pipe with insulation

My skills not being adequate to run copper along the path used by the iron pipe, I investigated "plastic" plumbing.  What limited experience and training I have is with metal, but I was told by several merchants, that this stuff is the future and it was only the "old" blokes that won't use it, so I decided to give it a go.  It's more expensive than copper, but allowing for the need for supports every half metre or less, it is very quick to work with and has a 50 year guarantee (I am an  "old bloke", so I may not be able validate that).  I would not have pressure tested a copper pipe, but I did with the plastic and it held 20 psi for 15 minutes, what pressure drop there was, was probably due to the attachment of the pressure gauge which might have been a bit flaky.  The job was more like running cables than plumbing.  This takes me back to my starting point, if labour is expensive, then productivity becomes important and this seems to be the driving force behind the enthusiasm for plastic plumbing.

Plastic plumbing (before making good the plaster)

At the time of writing, I have yet to connect the pipework to tanks and taps, what I'm hoping for is a much lower heat loss as the water moves from the hot water cylinder to the taps.

Images added after original post

This lead tee join supplied the bathroom with water from the main

Small Things

Some time back a journalist friend got to visit a nuclear facility, he not only came back with some good stories but got to wear a hard hat.  For whatever reason, for the past couple of years I've become my own builder and have been renovating my house.  The project has got to the stage where not much more can be done until the plumbing has been dealt with.

It seems that the current system is at least the third version.  The house was build in 1901 with an

extensive network of gas pipes which supplied mantles around the house and geysers in the bathroom and scullery.  A geyser is not a bad solution to the hot water problem, it heats water where it is going to be used, thus if you want 20 liters of bathwater, that's all you pay for.  I suspect that the original device discharged it's combustion products into the bathroom as there is not evidence of a vent to the outside world.    The current concern would be risk of carbon monoxide poisoning but the original inhabitants probably appreciated a warm bathroom.

Around 1950 someone thought that central heating was worth a try.  I'm guessing that the original solid fuel range was replaced by some coal burning object.  The geyser was dispensed with and bathroom was supplied with hot water from a tank in the kitchen via iron pipes.  If this arrangement bought any benefits they were short lived because rust and calcium deposits soon obstructed the flow of hot bath water.  Whilst the choice of pipe material was less than ideal (was there an alternative at the time?), it was installed with great skill along the shortest possible route.

By 1980, the house must have been inhabited by cold, unwashed people.  Someone decided enough was enough and installed a gas fired central heating system with copper pipes.  At that time energy was cheap and labor expensive.  The logical pipe routes were taken up by thick iron pipes, the alternative route from boiler to bathroom required a run of 50 meters of 3/4 inch pipe. which required approximately 15 liters to fill.  To get enough warm water to fill the basin for a shave or make-up removal resulted in running about 25 liters of hot water.  The hot water cylinder has a capacity of 100 liters and is heated by a 20 kw gas boiler (approx. cost: £2000) .  To summarize, the most energy efficient/environmental friendly way of shaving or doing the washing up is to boil a kettle (approx. cost: £20).

The big project is to reduce the pipe run from 50 meters to 10 meters.  Will it make a big difference?  Probably not but it will make a small one, both gas and water consumption should be reduced, maybe by 3 - 5 kwh/day and 25 liters/day respectively.  However, scale these saving up to a million homes (the UK has more than 20 million of them) and the reduction might be significant.  A plant producing 5,000,000 kwh is the type of place where you have to wear a hard hat.

Taking the temperature

In recent years I have become interested in the relationship between weather data and the potential output of wind and solar devices.  Today there are a variety of reporting mechanisms which provide regular and reliable data including automated weather stations, offshore buoys, satellites and the internet of things to which many small weather stations are connected.  All this stuff gets dumped into databases and is an incredible resource.

In the early seventies I had a brief career as a merchant seaman, by general agreement, this was not a good choice and a decade later I was working as a computer programmer where I was only a minor hazard to those around me.   However, the experience did give me an appreciation of conditions offshore where the wind can be smooth and steady and then become violent in a storm.  Offshore installations have to be built to withstand extreme conditions,

One of the more agreeable jobs on the morning eight to twelve watch was taking the sea temperature before the weather report was sent (in morse code) just before noon.  An alternative was chipping and scraping which was not agreeable.  This task was not without risk.  The ship was moving at around 14 knots and the drill was to throw a bucket on the end of a line ahead of the ship where with luck it might end up just below where you were standing and then haul it back onboard and poke it with a thermometer.  If you were not quick, the bucket went aft and became a small sea anchor.  The biggest risk was losing the bucket in which case one would have to explain to the bosun the loss a valuable item of equipment and request/steal a replacement.  A related problem was staying calm whilst spectators expected you to loose the bucket.   It was good practice to tie the shipboard end of the line to a railing, this cut down the loss of buckets but at the risk of getting fingers trapped between rope and railing.  In a calm sea it was not too difficult to stay dry, but if the ship was rolling and the bucket was full on arrival, there was a chance of a wet boiler suit.

I think that current practice for measuring sea water temperature is to have a sensor on a cooling water intake which takes the fun out the process at the expense of better data.  If the weather conditions where such that risk of bucket loss was high, then no data was collected.

This experience taught me to be both respectful and cautious of environmental data

Clear Sky Fraction

I live in a temperate maritime climate (i.e. the south coast of England) where clouds in various forms are frequently present in the sky.  Some simple experiments using a very small solar panel suggested that clouds have a significant effect on the performance of solar devices.  On a clear summer day, the global horizontal irradiance (GHI) at noon can be close to 1000 watts/ms, a few days later when the sky is overcast this can fall to less than 200 watts/m2.  In winter, the higher frequency of occurrence of clouds further increases the overall attenuating effect.  Also, the nature of the irradiance changes, under a clear sky the diffuse fraction might be around 15% with, under an overcast cloud sky, the diffuse fraction rises to 100% and there is no direct beam irradiance.  I wanted to quantify the attenuating effect of clouds one possibility is a statistic called the clear sky fraction (CSF).

This work has not been reviewed and should be treated with caution.

CSF is defined as the ratio of observed GHI under a cloud sky, to the estimated GHI under a clear sky (i.e.if the clouds were not present in the sky).

Unlike wind whose velocity can be more-or-less over several hours, solar irradiance is constantly changing, it is close to zero at sunrise and sunset and at a maximum around solar noon.  This makes it desirable to use a ratio which is independent of Sun-Earth geometry. The principal input for models of solar irradiance is air mass (AM) which is a ratio describing the amount of atmosphere the Sun's rays most pass before reaching the Earth's surface.  At solar noon close to the equator, the value of air mass is close to 1, whilst it is approximately 15 around sunrise and sunset in the temperate latitudes during the summer.  Based on observations in the south east of england, the author suggests that the "economic" range of air mass values is in the range 1 to 6.  At an air mass values of 6, the zenith angle is approx. 75 degrees (corresponding to an altitude of 15 degrees).  Depending on the terrain, when the sun is low in the sky, the shadow of hills, trees, buildings etc. effect the irradiance up a flat surface.  Experience suggests that within the range 1 to 6, CSF is more of less independent of air mass.

Horizontal irradiance was chosen because of the importance of diffuse irradiance under a cloud sky. Under a thick overcast sky there is no direct beam element to the irradiance which is all diffuse and is evenly distributed around the hemisphere of the sky.  Whilst it would be more convenient to consider a sloping surface (which is the normal way of mounding most solar devices), this would not account

 for all the diffuse irradiance.  Also, GHI is the most commonly collected form of solar irradiance data.

A problem in calculating CSF is the choice of method for estimating the clear sky irradiance.  There are two options.  The simplest is to use some form of model, many of these use atmospheric data such as water column and aerosol optical density and if this data is available, are capable of producing good estimates of direct and diffuse irradiance, the downside of these models is that detailed atmospheric data may not be available for the location where the observations are being made.  An alternative is to use observations of clear sky irradiance at the chosen location and the correlate thises with air mass.  Either approach has a degree of uncertainty associated with it.  not least of which is that whilst the reflection and absorption of clouds will be the dominant atmospheric effect, others such as moisture content will also have an impact.

I am currently messing with cloud sky models of irradiance which are based on CSF.

The Signature of Clouds

Experience with a 4.5 watt solar panel in 2009 showed that clouds were a significant factor in the energy yield of the device.  Under a clear, summer sky the panel might generate a current of 300mA at noon, under an overcast sky in the same month, this would drop to less than 50mA.  My first attempt at understanding the attenuating effects of clouds was to sit in the backyard with a flat photodiode and a multimeter and watch the output change as clouds passed overhead.  Later I found some datasets which allowed some form of statistical analysis, whilst these have been instructive, there is a lot to be learnt from simply staring at the sky.  Whilst the objective was to suggest some form of model which related observed cloud cover to the attenuating effect of clouds, the variations in the meter readings suggested that cloud types have distinctive signatures.  This post is based on some hand sketched graphs based on staring at a digital multimeter.  I have recently acquired a Raspberry Pi and an interesting project would be to explore this concept further using the Pi to record images of the sky and the output of a photodiode.  One day...............

One way of describing the attenuating effect of clouds is the Clear Sky Fraction which is defined as:

Clear sky irradiance is constantly changing, it is close to zero at sunrise and sunset and peaks at solar noon, the attraction of this ratio is that it is independent of sun-earth geometry.  Experience suggests that it is more or less independent of air mass for values in the range 1 to 6.  Under a perfect clear sky, CSF is close to 1.0.

Samples of CSF for a given cloud base and extent (excluding an overcast sky) will form a bimodal distribution, but the nature of short time series may indicate the type of cloud. The graphics below are sketches based on manual observation, rather than a comprehensive analysis from the output of a data logger, thus they should be treated with caution.

Cumulus is a common feature of an English summer sky, typically the CSF varies between 0.4 and 1.1.  CSF values greater than 1.0 occur when the edge of a cloud pass passes across the sun's rays causing a short period of increased diffuse irradiance.  The ratio of the duration of high and low periods depends on the extent of the cloud.

In winter, the sky is typically overcast with a thick layer of stratus, then the CSF is generally in the range 0.2 to 0.4 with only small random fluctuations.

 High level cloud, such as cirrus,  has a much less attenuating effect than types such as cumulus,

These sketches are the result of observations from a sky with only a single layer of cloud.  The author's experience suggests that as the number, extent and complexity of the cloud layers increases, the values of CSF tend to behave like an overcast sky, thus a complex sky might not fit these somewhat idealized patterns.

Cloud Poles

Google Earth and KML are useful tools for visualizing a varied range of datasets. A project which is well into extra time involves correlating the attenuation of solar irradiance with the cloud cover contained in the Metar reports used in aviation.  This project has, and still does present many challenges.  One of these has been the variations in the data contained in the Metar reports.  For example an international airport or big military base might report cloud up to 30,000 feet whilst a small aerodrome supporting general aviation might only report low cloud up to 6,000 feet and stations equipped with automated observing equipment  will report up to 12,000 feet.  The Cloud Poles were an attempt to make variations in reporting visible on a map, this is still work in progress.

Each reporting station is marked with a pole, each layer of cloud is represented by a polygon positioned on the pole to represent it's base height and the extent is indicated by the diameter of the polygon.  The surface color of the polygon is set by the base height, those representing low cloud are red, the polygons for medium level cloud are green and the high level ones are blue.  If no cloud is reported the pole is yellow and blue if there are one or more reported layers.  A yellow pole does not necessarily mean a clear sky, it may mean that medium and high level cloud has not been reported. The example shows cloud reports for Texas at noon on a randomly selected spring day in 2011.

The "front" end of the cloud poles application is a relatively small number of lines of Python code accessing an SqLite database.  The attraction of kml is that for some tasks, it can be constructed using nothing more than a text editor.

As I have messed with weather and related data in an effort to understand wind and solar energy, the combination of Google Earth and kml has provided a quick and easy way to explore ideas. for example, looking at the location of old windmills.  This could have been done just using Google Earth alone, but by using elevation data from the SRTM mission, it was possible to produce contour maps in the form of bitmaps and then overlay these on Google Earth.  This work suggested that many windmills are sited on ridges (hence the large number places called "mill hill") and on slopes exposed to the prevailing wind.

I did not develop the idea, but it is possible to use bitmaps displaying small graphs and use this a placemarks.  Each placemark can either have its own image file or select one from a palette by specifying an offset into a single, specially compiled image file, sadly, I did nor preserve an example of this work.