Special Project Report
  Building A DIY Aerosolar Electric Generator
 
 
 
 
 

Overview Of The Project

A Brand-New Way to Harness Solar Power

Introduction

The purpose of this project is the construction of a proof-of-concept prototype of a new type of solar technology.  I am adopting the name “aerosolar” as a convenient label for this unique method of harvesting solar energy. The term aerosolar is partially derived from the Greek aer (air) + solar (a generic english term meaning of or pertaining to the sun) - literally construed as “air sun”.

Why this new classification?  Aerosolar machines have modes of operation and characteristics that fall well outside the traditional solar technology classifications and yet have characteristics that resemble all of them.  Since a term of classification is often used as shorthand for an array of technologies and devices, use of a new descriptive terminology is warranted when such a group is not well described by older rubrics.

Consider the three main classes of traditional solar energy harvesting methods.  These are widely classified as:

  (1) solar thermal
(2) photovoltaics
(3) wind

Each of these classifications is based on the technical methods used to capture and convert incoming solar energy.  As might be expected, each main classification is further subdivided into numerous subtypes based on variations in the kind of hardware and methodology used for each.

But subdivisions aside, the basic classifications themselves reveal a lot about a given solar harvesting method.

Solar thermal systems, as their name implies, collect solar energy as heat and typically convert that into other forms of energy using heat engines or thermionic elements.  Thermal engines supply mechanical energy that is either utilized directly or converted into electricity using electrical generators.

Photovoltaic systems currently use semiconductors to convert solar photons directly into electricity (hence the name photo + voltaic) and, if needed, mechanical energy (using electric motors).  While semiconductors presently form the basis of the photovoltaic industry, other experimental methods of converting light into electrical energy are under development.

Wind power systems indirectly use the sun by capturing the mechanical energy of random atmospheric convection currents (wind) caused by solar heating, creating electricity by coupling wind turbines with electric generators.

All three of these traditional solar energy systems use collectors of one sort or another so constructed as to intercept the sun’s energy.  (i.e., flat-plate or reflecting concentrators, PV modules or wind-driven aerodynamic blades).

But the amount of power that can be extracted from solar thermal collectors and photovoltaic modules is limited due to the solar constant, clouds and darkness.  Prevailing wind speed and availability limits the performance of wind collectors.  Of the three traditional solar power systems, only wind collectors can operate after sunset without storage.  This useful trait is, unfortunately, counterbalanced by the unpredictable nature of wind.

Aerosolar devices can operate at night when the sun is not shining like wind and process atmospheric air to obtain power but do not rely on aerodynamics and natural air motion like wind turbines.  And while they use an absorbing component like solar thermal or photovoltaics, they do not rely on direct sunlight. 

Aerosolar absorbers are also more compact than solar collectors because energy is absorbed in a 3 dimensional volume, not on a 2 dimensional surface.  Since the surface of the aerosolar absorber is folded into a compact finned package, the amount of available surface inside the structure increases more rapidly than the outside dimensions. (Engineers call this effect the square-cube law) Moreover available power density far exceeds traditional solar collector values because it is not based on the solar insolation constant but rather upon the quantity of air processed by the system.

Aerosolar technology might be considered a subclass of the solar thermal category except that there are nano-electronic versions of these devices that skip the thermodynamic conversion step entirely much like photovoltaics or solar thermionic generators.

Aerosolar, as its name implies, indirectly uses solar energy in the atmosphere like wind, is as dependable as solar thermal and photovoltaics but does not suffer from the limitations or intermittent nature of those older solar production methods. 

This new solar technology is a radical break from past methodology that offers new engineering and economic tradeoffs that could finally bring solar power into the mix of mainstream energy production methods.

A Solar Power Myth

Solar energy systems have rarely been able to compete with fossil fuels like coal or oil, even in the modern era.   As a result, an entire mythology has grown up around solar leading to the unwarranted and automatic assumption that it is too expensive and weak to do more than supplement fossil fuel combustion and more recently developed nuclear processes.

While solar energy is lightly supported because of the perception that it is a “part-time” energy source, fossil fuels and nuclear power are heavily subsidized because they are considered dispatchable power production methods.

Not that these mainstream sources are without challenges of their own.  Fossil fuels in particular are subject to cartel manipulation and wild swings in prices that have caused severe economic dislocations.  More recently there have been assertions by some, hotly disputed by others, of lasting climate damage caused by unrestrained burning of these carbon-based fuels.

Other energy sources like nuclear fission have been plagued by periodic accidents, some leading to massive and explosive radiation leakage into the environment - in spite of all assurances that it is a perfectly safe form of energy production.  Time and again, just as it seems that the risk of nuclear accidents is receding, an “improbable” series of events results in yet another horrendous nuclear meltdown, undermining public trust.

Nuclear fusion, a safer and even more powerful form of atomic energy conversion, has been under development for over 50 years and yet the most optimistic estimates place the first commercial applications of that technology at least 30 years beyond the present day.

There have been reports of another type of fusion energy, LENR (Low Energy Nuclear Reactions), often pejoratively called “cold fusion” by skeptics.  But the lack of repeatable and open public experimentation makes it uncertain as to when or even if that power source will ever be available.

So while solar energy slowly develops and improves, public interest and financial investment waxes and wanes with the rise and fall in the fortunes of the economy and mainstream power production.

Each time it looks as though solar energy will finally emerge as a mainstream power source, another unfortunate turn of events marginalizes it.  These periodic reverses further perpetuate the myth that solar is the power source of the future – and always will be.

Consider the most recent series of events.  Late in the millennial decade the price of PV modules was rapidly declining and utility solar thermal projects were gaining favor.  Investment was beginning to increase and it looked for awhile that solar was finally beginning to mainstream.

Suddenly in 2008 the worldwide economy collapsed spectacularly and brought most financial investment to a halt.  In the near-depression that followed, solar energy struggled to remain relevant as it became almost impossible to capitalize solar projects.

As economic conditions improved, solar had reached the point where hardware and installation prices had fallen enough so it began to approach economic parity with other forms of energy production.  But by that time certain developments in the fossil fuel industry (“fracking”) began to unleash torrents of oil and natural gas into world energy markets.  Solar once again began to encounter strong economic headwinds.

If solar energy is ever going to become a mainstream power source, a radical departure from traditional methods of using power from the sun is required.  Aerosolar technology is just such an end-run around the technical and economic problems that have plagued conventional solar technology.

It is cheap and easily constructed, the underlying technology is well understood, it operates 24 hours a day, 7 days a week and does not use expensive fuel.  It is not subject to accidental release of radiation nor does it produce pollution while in operation.

These characteristics make it the one solar technology that can compete directly with traditional energy sources.  Because it is a brand-new approach to solar power conversion, radical improvements to this already highly desirable technology will make it even more competitive as development continues.

Technology Development

I’ve been working on aerosolar technology a long time.  For all its potential, development of this new energy production method has not attracted the attention of academic, commercial or governmental organizations.

This is really a charitable characterization.  If anything, some of these groups have done far more harm than good to solar in general and aerosolar in particular.  I have documented this issue elsewhere so there is no need to dwell on it here.

The effort to build machines to use solar energy effectively began in a small private research and development program after the oil shocks of the 1970s.  Experimental research was subsequently carried on for almost three decades without any outside investment and was funded entirely out-of-pocket.  This absence of interest or investment is not surprising, given the bizarre inability of modern organizations to identify and fund promising innovation.

 
   
     
 
An Experimental Aerosolar Facility in the Early 1980s. Work at this experimental site laid the foundations for development of new alternative energy devices and associated technology.
 
  
 
   
 
 
A special gas handler was constructed for experiments to gather data on real performance of compression and expansion machines to validate theoretical models.  The unit had electronically controlled valves, digital rotational encoders and an ultra fast pressure sensor ported directly into the cylinder.  These features allowed measurements of the dynamic conditions within the machine for comparison with theoretical models.
 
 

Many of the early experiments were concerned with constructing machinery to process heat.  Research included collection of energy, fabrication of special heat sinks, experiments with engine and compressor processes and many other related research topics.  Later efforts were aimed at integrating the new systems into a wide variety of existing technologies.

Over time, an enormous amount of knowledge and information was amassed about the new technology.  A solid theoretical foundation was established for predicting the behavior and performance of the new machines.

Perhaps the most important information to come out of this experimental program is that the aerosolar concept is scientifically sound.   A successful outcome with practical machinery is not as difficult to achieve as some experts have suggested.  Moreover the foundations have been laid for radical and impressive improvements to the technology as it begins to make headway in the market.  These innovations will revolutionize energy production.

The Effect of DIY Projects On Industry Development

The decision to start this project came about because it is necessary to make an end run around the “gatekeepers” of development, manufacturing and marketing capital.  The parallels of events in the present experimental solar industry and the early microcomputer revolution are striking.

Amid much hurmphing, technology experts and mainstream organizations dismissed microprocessors as useless for serious work.  Moreover because of technical limitations at the time, practically all concerned were flagrantly downbeat in their prognostications for the new technology, pronouncing it as little more than a fad among a few hobbyists.

This view was reinforced by the fact that much of the technology was being built in garages and in a cottage industry on low budgets.  Yet precisely because of these conditions the innovative potential was staggering.

There were some large companies involved – those making the chips, for example.  This is comparable to companies manufacturing solar panels today.  Yet even these technology providers were skeptical and did not really do much beyond supplying a growing demand and incrementally improving the hardware.

The heavy lifting was left to astute and capable amateurs who saw the potential and had a vision of the future.  From humble beginnings the computer revolution snowballed through several iterations creating an avalanche of change and new companies, completely remaking the economy in the process.

Solar is likewise in these very same early stages.  And those who dismissed the computer revolution in the beginning are making similar noises about the solar industry now.  Attitudes across vast swaths of business and industry are that solar is at best a minor player in energy production and will remain so for a very, very long time to come.

Project Focus

As I considered the best course of action for the project, decisions had to be made about what technology was best suited to a DIY project and how to make it available to as many people as possible.

There had to be reasonably rapid progress.  And yet at the same time, costs had to be kept as low as possible.  But since the goal of the project is to build something more than a “demonstrator” (i.e., toy), justifiable costs could not and should not be a barrier.

While it made sense to continue the effort to interest capital sources in investment, the project should not be held hostage to the often-capricious investor community.  That meant a slow, steady low-cost approach was absolutely necessary.

There is also the matter or future improvements.  Since I’ve spent a lot of time and money developing aerosolar technology, I did not want to throw away that investment by voiding the patent rights with unlimited public disclosure of the results of research and development activities.

What was needed was foundation technology that was already well known and could be used in an open DIY project.  That meant using existing techniques and devices that might be less effective than fancy experimental “next-generation” gadgets.

Properly constructed and applied, however, even old technology could show the benefits of this new way of harnessing solar energy.  The fact that there would clearly be room for improvement of the equipment would not diminish the fact that the concept was sound.  It might even hasten development of innovative new hardware.

Another question was how the project might be received by those engaged in DYI activities.  Because the aerosolar concept has many applications, it would be very easy to overreach by trying to make it appeal to a wider audience.

The project therefore had to be narrowly defined and highly focused.   That meant the emphasis had to be on one specific form of the technology so as not to be all over the map.  The effort also had to have personal relevance – something I had a real desire to build and could use myself.

The specific target audience was another issue.  There would probably be interest among those who are avid followers of solar technology and people who might build from a kit or plans, if available.  But the primary and most likely builder would be the serious amateur.  Such people often build from scratch and are adept at scrounging suitable alternative parts and adapting alternate methodology.

The project also had to be relatively easy to assemble by those willing to invest a reasonable amount of time and money once the end result could be shown to be worthwhile.  The process also had to be step-by step so it could be accomplished after work and on weekends, as time was available.

An online project document also would have to be drafted with photos, videos, links and graphics so an individual could solve problems that might arise based on knowledge presented in the document.

Above all, the outcome had to be achievable and hold promise for the future.  That meant a “workhorse” device at the end of it all.  It also meant that it would be necessary to detail “how-to” stuff  - like where to get certain parts, pitfalls to avoid as well as alternative methods to provide more than one route to success.

And one of the most important considerations was that the endeavor should cause interested people to start their own aerosolar projects.

One additional concern is the place where DIY amateurs live.  While it is not out of the question that somebody in the wilds of Africa or the Amazon jungle could engage in DIY construction – and many do, the current geography of technological development tends to be much closer to civilization.

For the first iteration of an aerosolar DIY project I decided to stick with a project that could be built where people have some financial resources and where technical literature and specialized parts are available.

My hope is that once aerosolar technology is unleashed, some enterprising DIY amateurs will push the boundaries.  And perhaps a few suppliers will notice their products are being used for something new and will begin to cater to this new market as happened in the computer industry.  I have no doubt that will ultimately happen – but only if the technology gets into the hands of motivated amateurs who begin building aerosolar devices.

Safety

Almost every time someone contemplates building something instead of buying a manufactured product, there are invariably people who come out of the woodwork and begin scare mongering.  There are always some who are so averse to risk that nothing is ever safe enough and there are always hazards that justify talking everyone out of everything.

Fortunately innovators have always been willing to assume reasonable risks or we would still be in the caves.  Nothing is ever completely risk-free and thousands of individuals are injured or killed every year doing things ordinarily considered “safe” by reasonable people.  Just crossing the street can result in an accident.  But that is no excuse for taking unnecessary chances or blindly creating dangerous conditions.

As any DIYer who has ever built a major project knows, it is very easy to get careless and make mistakes that can cause the neighbors to get very concerned or result in the experimenter making a trip to the emergency room. (or the funeral parlor) The old adage, ‘plan your work and work your plan applies”.

The temptation to “get started” should be resisted until you have familiarized yourself with all of the elements of the project.  That means more than just reading these project documents.  This guide is an educational tool, nothing more.  It does not pretend to be the last word on the subject.  You need to consult other sources of information and have actual experience in building things before you begin your own project.

The author of this document is providing it only as educational material and does not accept any liability for how it is used.  Work carefully and safely so you don’t end up creating unnecessary hazards.  To do otherwise is to invite a visit from the authorities, spending project money at the local hospital to get yourself patched-up and providing grist for skeptics and the local news media.

The Online Solar DIY Wasteland

Anybody who is seriously looking for solar information has probably thoroughly searched online and been disappointed with what passes for alternative energy projects.  The outcome of such searches vividly demonstrates how rare really good solar DIY projects are.

Along the way one sees practitioners who rehash the same old basics over and over again without adding anything new.  Like how to build solar panels, for the umpteenth time.  Once in awhile a solar project does rise above the rest.  I’ve discovered one or two that offer interesting variations and hard-to-find information.  But who hasn’t clicked on a promising solar project link only to find the ever-popular (and mostly useless) toy Stirling engine video?

There are also a few websites that do have good technical information useful to the DIYer but many lack any sort of focus so the result is often a mishmash of disconnected themes, a few hare-brained ideas and over-written academic papers.

Here and there are a few really serious attempts at alternative energy or DIY solar projects.  These run the gamut from corncob-fired steam engines, to large reflective solar arrays powering a steam-driven electric generator of a few kilowatts.  While these are interesting, they don’t accomplish much that couldn’t be done by using conventional solar PV modules that are a lot less trouble to operate.

And then there is my personal favorite – videos that begin with “Hi!  I’m… (fill in the name)… and here’s my new solar… (fill in the blank) that runs on… (sometimes steam but typically on air from an underpowered source).  Most of these feature cobbled up air compressors and old beater lawnmower engines barely ticking over unloaded.

But at least such efforts are justifiable as first steps towards experimental projects.  Most solar technology offerings are just demonstrator toys purchased from educational suppliers with a dog or cat video thrown in here and there for good measure.  The most annoying of these incorporate a soundtrack of music that only the person uploading the video could possibly enjoy.

And anything radically new?  Forget it.  Something like a brand-new technology that can be built by DIY amateurs just doesn’t exist.  It was against this backdrop that I began to see the need for a truly unique DIY project.

Choosing the Project Device

Of all of the devices that appear to offer the most potential for a good aerosolar project, two seem to stand out above the rest - air conditioners and electric generators.

Every summer my air conditioning bills get higher and higher as the electric power company rates go up, seemingly without limit and regardless of the actual cost of power plant fuel.  The more consumers try to reduce electric consumption, the higher the price becomes.

And perhaps the most maddening element of commercial electric utility advertising is the ceaseless ballyhoo about how much they promote solar energy.  Yet these very same utilities seem to be constantly filing for rate increases with the local public utility commissions and paying lobbyists to get legislation introduced that has the perverse effect of repealing solar incentives and preventing the spread of solar technologies.  Who knew?

Most of us use less electricity now than we did even a few years ago.  But power bills are even bigger than in times gone by.  When it comes to my electric utility bill, I sometimes feel I’m on a treadmill where I have to run faster and faster just to stay in one place.

Based on these considerations, either a solar-powered air conditioner or solar-electric generator would have broad appeal.

Since I live in the Arizona desert where it REALLY gets hot, aerosolar air conditioning makes a lot of sense.  But many people live in more temperate climates where the need for air conditioning is not as big a concern.

A few hardy souls live in cold climates where the last thing anyone needs is an air conditioner.  And if someone needs an air conditioner or a heat pump, these are readily available - if you have a source of electric power.

Another consideration was to keep the complexity of the project to a bare minimum.  Air conditioners today are not the simple machines of earlier times.  They are only relatively easy to construct if you have a manufacturing plant geared to such things.

An engine is a lot easier to build as a DIY project in a home workshop or garage in comparison to an air conditioner.  Not to say that such a project is trivial – that’s certainly NOT the case.  But an aerosolar engine has fewer components, requires less technical knowledge and is a lot less finicky than an aerosolar air conditioner.

After reflecting a bit, I decided to feature construction of an aerosolar electric power generator.  Plugging into the Earth’s planetary energy and creating power out of “thin air” like a thunderstorm or hurricane does have a certain appeal.

After several abortive attempts to have solar PV modules installed at my house, I’ve come to understand that a conventional PV array is still way too expensive.  Anything cheaper to construct than conventional solar panels that works when regular solar energy devices are useless also makes a lot of sense economically.

I do wish it were possible for aerosolar power generators to take advantage of the state and federal subsidies that are offered for conventional solar installations.  That would go a long way towards advancing radically new technology.

One of the best states for solar power of any sort is Arizona.  But a few phone calls quickly made it apparent that neither the state nor the federal government was interested in paying subsidies for a DIY installation using a brand-new technology.  So much for encouraging innovation.

The Real Nitty-gritty

With broader considerations out of the way, the time finally arrived to begin planning the actual details of my aerosolar power generator.  I quickly realized that no matter what I did, this was going to be one of the most controversial steps in the project.

I fully expect to be criticized for choosing this or that method, part or design philosophy.  My answer to such critics is that I just showed you how to build the thing.  If you don’t like my choices, feel free to build it a different way.  If you do it better and publish your project, we’ll all do it your way.

Whatever you do don’t just complain – get out there, build one and tell the rest of us about it!  Remember, these are the “wild west” days of the solar industry.  If you really have your head screwed on straight we’ll be hearing about you in the news and you might just be the next big thing.

As was noted earlier, this version of the aerosolar engine utilizes only low-cost, conventional and well-known technology.  That means we can’t use “unobtainium” or rely on pricey technical means and devices still in the R&D lab.

This is old-fashioned equipment put together in a way that operates to extract solar energy from the atmosphere.  That is really something worth accomplishing.

It won’t be the last word in efficiency or impress those pesky critics who insist on seeing the negative side of everything.  But it will provide mechanical and electrical power in a quantity at least as great as some of those high-priced solar panels.  And it will do so most of the time – not just when the sun is shining.

Getting Started

The first order of business is to decide on the basic technical approach.  Since we don’t want any unexpected surprises, we’ll use some old-fashioned equipment as was noted earlier.

Any solar engine needs a source of heat and a heat sink.  While the sun ultimately supplies the heat, there must be a device to channel it through the engine.  And since no engine can convert all the incoming heat to power, there must also be a heat sink to reject waste heat to.

For our aerosolar engine, the device channeling the sun’s heat through the engine is called an absorber.  It consists of finned coils that look much like those found on air conditioners and automobile radiators.

Here in Arizona the air gets so hot that pulling in enough heat is not really much of a problem.  There are important technical details to be sure, but when the ambient temperature is 110 to 120 degrees Farenheight, the air literally feels like it’s coming from an open oven door.  No one who ever felt a hot desert breeze will doubt that there is plenty of power in that air.

Anybody who uses a pair of binoculars to look across vast desert landscapes out west in summer has witnessed the shimmering air currents and dancing images that betray atmospheric heat.  Take a look at the back end of an engine on a jet plane as it slowly moves along the airport runway and you’ll see the same effect.  Only the amount of heat coming out of a jet engine is like a drop in the ocean compared to the amount of heat in the desert atmosphere.

The heat that the aerosolar engine rejects needs to pass into a heat sink at a lower temperature than the source of heat.  Fortunately that problem was solved by nature long ago.  Storms are powered by the evaporation of water into air.  That’s how this particular version of the aerosolar engine heat sink works as well.

While it’s true that we humans have pretty well made a mess of our fresh water sources by overuse and pollution, there is no shortage of water on earth.  We live on a planet where almost 3/4ths of the surface is water.

We are experiencing fresh water shortages because we just aren’t bothering to make more and transport it to where it’s needed.  Why lift a finger to make or move fresh water when nature provides so much of it?

Unfortunately that way of thinking has just about reached its limits.  The best way to eliminate a shortage of anything is to make more.  Conservation helps but it only goes so far.  After a certain point the law of diminishing returns sets in.

While I’m sure that using a little water to power an engine may upset some, the fact is we’re already doing it.  Almost every electric generating plant on Earth uses a water-cooled heat sink – and burns fossil fuels to boot.

And most homes in dry, hot desert locations around the world use evaporative coolers of one kind or another.  If you want to be upset about water use, kindly direct your complaints to the operators of lush golf courses or homeowners who insist on growing grass lawns in the desert.

Indignation about aerosolar water use is misplaced and shortsighted because such technology will ultimately solve the growing fresh water problem.  This version of the technology operates on the same principle as hurricanes and thunderstorms – evaporating water.  The water used in the engine can be salt water or brackish, polluted water.

After being evaporated and powering the engine, that water can be condensed as fresh water, ready to be moved to where it is needed to supplement natural sources.  The power to do this is already being supplied by the sun every day.  The aerosolar engine in this project is the first man-made device that is literally plugged into the Earth’s hydrologic cycle. 

The available power is truly staggering.  Our current energy use from ALL sources is about 15 terrawatts or so.  Solar energy available in the Earth’s atmosphere is AT LEAST 33,000 terrawatts.  That is just the heat absorbed directly by the atmosphere.

That amount is even greater if you count reradiated heat from the surface absorbed by the atmosphere.  The power source for aerosolar technology is almost literally limitless.  More than enough to make and move all the fresh water we will ever need and generate more mechanical and electrical power than we can possibly use.

Preliminary Design Considerations

The next step in the DIY aerosolar process is to choose a working fluid for the aerosolar engine.  This can be an exhausting and very convoluted process because it means weighing the advantages and disadvantages of everything from steam to organic vapor.

It also means paying attention to some pretty daunting details like thermodynamics and physics along with a lot of other subjects that give most of us a headache.  The working fluid you choose will be governed by conditions under which the system operates.

On top of this, an aerosolar device requires detailed knowledge of long-term local climatic conditions as well as cost-benefit relationships.  Large companies typically spend decades and tens of millions of dollars on these initial steps.  And prominent scientists make careers out of publishing lengthy papers on these subjects.  A DIYer just doesn’t have the luxury of overanalyzing such things.

That is not to say you should fly by the seat of your pants.  That is foolhardy.  There are simple but effective steps you can take that will ensure a successful project.  You may feel that more or less emphasis should be placed on one or another of the preliminary steps and that is the experimenter’s prerogative.

But never forget that when the big day finally comes and you press the start button, all that stands between you and an expensive dud is the early planning work and good execution of the later steps in the project.

Ideally you should already “know” it works before you ever test the device.  The experiment only confirms the soundness of the scientific, engineering and construction techniques behind it.

Local Climatic Conditions

Since I live in a small Southern Arizona town between Phoenix and Tucson, I want to know what conditions the aerosolar engine will have to deal with in order to extract atmospheric energy over a period of time.  You will need to do the same research for your particular area.  This isn’t always easy but you can usually find such information online.

Ideally, you need graphics to get a good picture of local atmospheric conditions over time.  Since you are looking for long-term trends, a graphic presentation format will save you long hours of pouring over years of tabular data.  I got lucky and found a complete set of climate graphics online at Weatherspark.

WeatherSpark is a new weather website with climatological graphs that allow you to view long-term data from many weather stations all over the world.  It was still in beta testing at the time I wrote this article so there may be glitches in the data but it works pretty well already.  Weather stations also occasionally report incorrect values and the people at Weatherspark are slowly weeding those out.

There are currently over 4,000 weather stations and more are being added as time passes.  In my case data comes from the local airport and is complete and reliable from 1992 through 2012.

While data from these sources can be helpful in advance planning, most of the information tends to be averages for the region and not very helpful in determining specific on-site conditions.  You will need to purchase or scrounge a digital thermometer and wet bulb instrument for your project to get that data.

I found a really good deal on a hand-held Amprobe brand THWD-5 temperature and relative humidity probe with a sensor that is attached to a cord with a mini-DIN connector.  The functions include wet-bulb temperature as well as dry-bulb temperature.  The probe is attached to the unit with a cord meaning I could not only check the ambient environment but also monitor conditions inside an operating aerosolar system as needed.

I immediately began collecting random samples of local ambient dry-bulb and wet-bulb temperatures for the next year.  Since the project was on a low-cost, slow track and I had a lot of other expenses on my plate, this course of action made progress on my project less rapid.

But under the circumstances this was acceptable for me.  The data I gathered also gave me a lot of insight into the temperature differentials that I could expect to have for my engine.

On the high side of the range, a dry bulb temperature of 104 F (40 C) and a wet bulb temperature of 60 F (15.5 C) results in a delta-T as high as 44 F (24.5 C).  More typical temperature differentials were in the 20-plus degree F delta-T range.  In a few cases the lowest delta-T was 3 degrees F, which was fortunately a very small amount of the time.

That meant using older technology would result in some small number of days when there would not be enough available delta-T to operate.  Still, a look at the entire year’s worth of data revealed that for the vast majority of the time I could count on having at least some operational capability.

By now the skeptics will be carping that these temperature differentials are so small as to make construction of an aerosolar engine impossible.  Let me just take a moment to point out that ocean thermal energy conversion (OTEC) uses similar temperature differentials and has been successfully employed to produce electrical power at various projects all over the world.

Nobody said it would be as easy as burning fossil fuel – which gets at the point of doing this to begin with.  If you want easy, go get yourself a gasoline generator.  Be prepared to shell out whatever the oil producers want to charge you for the privilege and content yourself with breathing air that has been through an internal combustion engine.

 

(To Be Continued)