Thursday, May 14, 2009

Construction of Alternate Power Source

Previously I described the different practical alternate power sources that I could use to power my Deep Deep Dark Green computer system but I have not touched upon some items that need to be discussed. One item is how to get the maximum efficiency from the alternate power source. Just taking a solar array, slapping it on top of a house, connecting the array to a voltage regulator then connecting the voltage regulator to the battery seems like the thing to do but there are some issues that need to be taken into account to maximize the efficiency of a power delivery system. Since we are dealing with limited power resources as we only have sunlight for some part of the 24-hour "daily" cycle, and the total amount of sunlight varies from Summer to Winter we need to optimize our power system as much as practical.

Since I am using solar cell technology for the prime power source for the deep deep dark green computer system I need to determine approximately how much electrical power I will potentially have available for the project. In doing some research I ran across the chart you see to the right. I would suggest you right-click on the image and open either a new tab or window to view the image as it is rather large in size - about 40-km per pixel displayed but gives you a pretty good idea of how much energy is potentially available in your area of the United States. My locale is on the east coast of Florida - yes, I can watch space shuttle launches from the front yard (grin). My area receives about 4.0 - 4.5 KWh per day per meter of surface area. Not too bad - of course this is for a clear day so I expect it to be less. My hope is the solar array I have will be large enough to supply the power I need for the computer system to be used for about two to three hours a day. The total per day use of the system may be higher or lower but that is about the average per week I use the computer - and of course it is possible, with the system I am using to have the computer go into a power-saving mode when not actually being used.

Given all of the power derived from sunlight is supplied by the solar array we need to make sure we are using the most optimum methods to collect the sunlight for the solar array. We don't want to be wasteful here as the solar array is the power "input" for the rest of the system. We need to insure we derive as much usable power as we can since everything from the solar array to the power storage system induces some loss of the collected power. Just the nature of the real world. I figure the solar array I have is around 10% efficient - in other words it will convert around 10% of the solar energy to electrical power as long as it is receiving direct sunlight.

The "total" square meter area of the solar array I have is around 0.28 sq. meters in size ( 1-foot X 3-foot). Given the potential solar energy in my area of the world is around 4-kWh per day per square meter of surface area then the best possible conversion I can expect is around (0.28 X 4000-watts) 1120-watts per day. Sounds wonderful - but - there is a problem using such a simplistic calculation. The calculation assumes you would collect ALL the solar energy falling on the 0.28-sq. meter area on a given day AND you had perfectly clear days all the time. Not going to happen in my case or anyone else for that matter!

There is also the problem of incidence angle - the angle of the solar array surface relative to the Sun's position in the sky directly affects the total energy conversion process. To extract the maximum amount of energy from sunlight you want the sunlight to shine directly on the solar array. Any deviation from having the sunlight strike the solar array directly reduces the collected power output from the solar array. An example would be the solar array directly faces the Sun at Noon but it is 9-AM in the morning. The Sun's apparent angle in the sky at Noon is directly overhead (for this example) but is approximately only 45-degrees above the horizon at 9-AM (assuming the horizon is 0-deg and Noon is 90-deg). If the solar array is oriented to receive the maximum amount of sunlight at Noon then the angle of incidence with respect to the Sun will be 45-Degrees at 9-AM. The power output from a solar array referenced to the angle of incidence for the sunlight striking it follows the Sin of the angle of incidence. What this translates to is a reduction of 15 - 25% of the total energy potentially collected by the solar array. Of course to capture the maximum amount of energy possible there needs to be a method to "track" the Sun across the sky which increases complexity and power requirements (something has to drive the solar array to track the Sun).
You can calculate the loss due to the angle of incidence difference between directly on the solar array verses a different angle by just looking at the angle value of the difference in the table on the right and multiplying the total power output value for the solar array by the Sin value for that angle. It is pretty close and accurate for most practical applications. At least my solar array follows it pretty closely!

Given the above information we can get closer to what is actually expected in terms of total power potentially available from the solar array. I am using a fixed position solar array that is mounted on my home's roof (which is south facing) and the pitch of the roof is such that I do not need to adjust for the latitude location (28.2-deg. North) as the pitch is pretty close already ( about 24-deg.). I am making the allowance of the angle difference on the conservative side and reducing the possible energy collected by 5% to compensate. Given the angle difference is only about 4-deg. and based on the Sin Chart I would expect a reduction of around 1% of the value I am going with a very conservative estimate here!

The following are the percentage values of loss for the different variables previously described:
  • 5% for difference in solar panel angle vs latitude location.
  • 3% for the cover glass on the solar panel (remember the cover glass?).
  • 25% for the fact it is a fixed position solar panel (conservative here again).
This gives me a net loss of around 33% so I am going to go more conservative with a 35% loss to work with. Now, the total potential energy that falls in a square meter in my area works out to be between 4 - 4.5 KWh total for a day. Given the solar array is approximately 0.28 square meters is size that will reduce the total potential energy available to 1.12 - 1.26 KWh total for a day. We can not get that much power as the solar array would have to be 100% efficient in converting all the sunlight striking it to electrical power so we need to multiply the total potential energy by 10% (0.1) which yields around 112 - 126 watt-hours total per day Now you see why there is a big move to increase the efficiency of solar cells! 85 - 90% of the total potential power is lost due to the conversion efficiency factor of the current solar cell technologies.
Now we know the approximate total available power our solar array is capable of if everything is optimal for collecting the available sunlight. We do not have an optimal configuration as the solar array is in a fixed position (does not track the Sun) and is not at the optimal angle for the latitude location (24 vs 28.4 deg). Given these two inadequacies we have to multiply our previous calculation results by 0.65 (35 % loss) to account for those incurred losses. The calculated value of the total potential available power per day works out to 73 - 82 watts-hour for the day. That is a far cry from the total potential power available over a 0.28 square meter but it still does not take into account everything! This sure adds a whole new meaning to "losing daylight"!
Solar array specifications can be a little misleading (say it isn't so!) where the manufacturer specifies the "total power" the panel is capable of collecting. They use the maximum voltage the panel is capable of producing then will increase the amount of current drawn from the panel to reduce the voltage produced to about 80% of the total "open circuit" voltage - the current times the voltage is the "power" rating for the solar panel. This is well and good if you have the power storage system operating at the solar array 80% open voltage point but most battery storage systems do not. Case in point - the solar array I am using is capable of generating an open-circuit voltage of 20-VDC is direct sunlight. This number is empirically derived (took the panel out in the sunlight at 1-PM on a perfectly clear day and measured the open-circuit voltage). While it is nice to get that much voltage I don't have any battery storage systems that operate at the 80% value for that voltage ( 16-VDC ) but instead use around 13.8-VDC for the charging voltage. Since the solar array I am using is rated at 20-Watts at 16-VDC I have to "de-rate" the solar array to take into account the lower voltage of operation - which works out to around 14 % less power available, or around 17.2-Watts for the solar panel. What all of this means is the solar panel will not supply it's rated 20-watts of power in direct sunlight due to the lower voltage of operation required for the battery charging operations so I lose about another 14 % of the total potential power available per day (this one always trips people up!). So now my 73 - 82 Watt/hours per day potential energy drops down to 14 % less or about 63 - 71 Watts/Hour per day. We are starting to get a little "slim" on power here (grin). As you can see there are a good number of variables and trade-offs that can affect the total efficiency of a solar system. In my case I will be running at the lower end of the efficiency spectrum due to simplification of the system. Given the power limitations of the computer system to less than 20-watts total power draw the above calculations indicate I should be able to run the system for about three hours total on a really good day. Of course - the lower the power drain by the computer system the longer the operational time. I may be adding an additional solar panel to my system in order to get longer operational time. At $90 for a panel it is not too expensive to do this and may still be within budget.
Bottom line....
Some may think this is just not worth the effort that is required to build and install a solar array power system. And, for the most part, they would be correct if you did not take into account the possibility of no power being available! Case in point - I live in an area that is susceptible to power outages due to such things as Lightning induced or Hurricane induced power outages. During the 2004 Hurricane season I saw five different storms affect my area with a resultant power outage of three days for each storm. I personally know people who were without power for weeks on end due to the storms - downed power lines that were not restored for weeks are not uncommon from Hurricanes. My biggest issue with no power was the lack of communications during those power out days - even the phone lines and cell phones were not working for a couple of days after the storms. The phone lines were down for various reasons - no power at the telephone sub-station due to problems with generators or batteries being discharged. The cell towers had the same issues. Hopefully they have taken steps to correct those deficiencies but being telephone company owned I do have my doubts - does not add to their bottom line and they would just claim those are rare events anyway. Having a self-powered system would have been an advantage as I have a satellite Internet system so I would have had communications if I had a self-powered system. I would not be at the mercy of the local telephone companies for communications...

Friday, May 8, 2009

Alternate Power Sources

In looking at the power requirements for a home computing system I decided it needs to be as compact and unobtrusive as possible - don't want to upset the neighbors (grin). The alternate power source or sources must be safe to service and maintain. Since I am looking at different alternate power sources and the system is not connected to the local power grid it goes without saying there will need to be some form or forms of power storage. These methods of power storage will need to be safe methods, which goes without saying (grin).

Alternate forms of practical energy:

The following describes a couple of the practical alternate energy sources I have found to date. It is by no means an exhaustive list or comparison of potential energy sources but does describe some of the information that I have collected over the course of the last several months in researching an off-grid power source for this project.


Currently there is a great push to move some of the world's power source to Solar. In the research I have been doing lately there are some very interesting progress being made in this field - specifically in the types of materials used for solar power generation. There is even some talk of solar paint with the capability of generating electrical power from a "paint". If course these types of power sources are still "on the horizon" so I am not looking at them directly. I am keeping more with existing commercially available hardware which limits the list to just the normal silicon-based solar panels or thin-film technologies solar panels. Both types of solar panels available to the home experimenter I think it is the best method to approach solar power applications at the present time. I found a source of thin-film solar panels with a 20-watt rating - but - that is at an output (in direct sunlight) of around 18-Volts. Since normal lead-acid storage cells (batteries) run around 12.8-Volts the actual output from the solar panel will be more along the lines of 13 or so watts. I am trying to keep the cost of this project down to something reasonable so given this solar panel is around $80 I may go this route. As you keep reading you will see why shortly.

Hydrogen/Oxygen Fuel Cell:

Fuel Cell technologies are a "hot" topic, not only in fixed power systems but also mobile power systems. The military and the automotive industry have a vested interest in mobile power sources for reasons I won't go into here since neither have anything to do with my project - I just wanted to mention them in passing as some of the technologies they are looking at also are directly applicable to my project.

Hydrogen/Oxygen Fuel Cells: Ahhh yes - the staple of the space program! Hydrogen/Oxygen fuel cells have been around for a good while and the method of operation is pretty well understood. Place hydrogen gas on one side of a ion-conductive membrane and Oxygen gas on the other side, add a catalyst and a method to conduct electrons from one side of the membrane to the other you get electrical current (the definition of current is electrons moving in one direction through a conductor). Sounds simple enough - but there is a little more to it than that.

First, you need a source of Hydrogen gas as fuel for the fuel cell. There are numerous ways to obtain Hydrogen gas but in my case the only viable method would be electrolysis - the other methods are way to complex for a home system and commercial sized systems usually don't scale down to home-sized systems very well. Secondly, you need platinum for the catalyst material in a fuel cell. While the requirement for platinum as the the catalyst material is not large (requires a very small amount) it is still rather expensive. Third - you need a ion-conductive membrane material that will conduct Hydrogen ions (an Ion is nothing more than a atom with an electron stripped off of it giving it a net positive charge) and handle the heat levels generated within the fuel cell. The membrane material needs to be rather thin to allow rapid transfer of the Hydrogen ions through the membrane but think enough not to break due to pressure differentials across the membrane - usually the membrane is around 10 - 20 mils think. Again - there is a cost factor involved not to mention the construction factor in fabricating a working membrane with the catalyst material coated on both sides of the active areas of the membrane. From some if my research there are sites on the Internet where you can learn to "build" a Hydrogen/Oxygen fuel cell and they don't look too difficult to construct. But - buying the materials to build a fuel cell then actually building one with a fair amount of efficiency are two distinctly different things! Not only are they not so easy to construct you will need to construct multiple fuel cells as they normally only have about 0.5-Volt output - you actually need a fuel cell stack to get enough voltage to be useful. If you are looking to produce around 5-volts, the voltage needed for my project, you will need to either buy or fabricate 10 to 12 fuel cells.

While I am not trying to dissuade anyone from attempting to build their own fuel cell stack it is not something I care to tackle myself - I will leave it to the companies that do that sort of thing best as they have the expertise and required skills to produce viable fuel cells. Besides, I don't have the time nor inclination to go through all of the steps to design and build an efficient fuel cell stack.

A second thing that turns me away from fuel cell technologies for this application is the fact they are still expensive! An average Hydrogen/Oxygen fuel cell stack that produces around 6-volts @ 20 Watts (around 3-Amperes of current) will set you back about $500.00 USD (that is my budget for the whole project!). If you have some interest in PEM (Polymer Electrolyte Membrane) Fuel Cells a good source for them, at a reasonable price, is The Fuel Cell Store for the 20-watt version (pictured to the right). Of course you will still need a method of storing the Hydrogen gas and a way to produce it as well! This fuel cell requires Dry Hydrogen gas at around 3-PSIG @ 280ml/minute to produce 20-watts of electrical power (6.6-VDC @ 3.3-Amps) so you will need at least some method to pressurize the Hydrogen gas and store at least 400+ liters of gas for a 24-hour operational period at full rated power. This does not sound like a simple method to me for achieving a cost effective power system for my project.

Ethanol/Oxygen Fuel Cells:

There exist other types of fuel cells which use a different fuel than Hydrogen. One such fuel cell is the Ethanol/Oxygen fuel cell. The basic operation is the same with one exception - the 'fuel' is Ethanol and the Ethanol Hydrogen/Carbon chain is broken down by catalytic action to release the Hydrogen ions for combination with the Oxygen to form water. Of course the Carbon has to go somewhere which is in the form of CO2 (carbon dioxide - a green house gas). While this form of fuel cell does add to the carbon footprint (releases green house gas) the fuel source is from a renewable energy source - that of fermentation of grains. Since the plants remove carbon dioxide from the atmosphere as part of the growth process you basically are just recycling the carbon dioxide instead of releasing "new" carbon dioxide into the atmosphere as is done with fossil fuels. There are some who would argue this defeats the purpose but in my mind it is not adding to the total green house gas problem. A second advantage with using an Ethanol based fuel cell system is you remove the issues of storing a highly flammable fuel - Hydrogen. To store Hydrogen in any quantity you need either a large storage tank for atmospheric pressure storage of you will need some form of compressor to pressurize the Hydrogen gas for storage under pressure. Given we are attempting to "save" energy it just does not make sense to run a compressor to store Hydrogen gas under pressure. With Ethanol all we need is a storage tank for the liquid - the Ethanol is acting as the 'storage' vessel for the Hydrogen used in the fuel cell system. Personally, I think it is a much more efficient storage system as you remove the possible Hydrogen Gas flammability issue. For those who don't know - Hydrogen Gas has a flammability ratio to air of 4% - 97% which means that anywhere within the two percent ranges Hydrogen is highly flammable - almost to the point of being explosive! The flammability range of Hydrogen is the highest of all flammable materials. Hydrogen as burns at a very fast rate - about 11000 ft/sec which makes it fairly explosive when burned (high expansion rate). Ever wonder why Hydrogen is used as the liquid fuel for the Space Shuttle main engines??? Now you know! Of course there are some current "drawbacks" to the use of Ethanol as a fuel for fuel cells. One of the drawbacks is the need for platinum as a catalyst material in the Anode and Cathode of the fuel cell. There have been strides made in the last year to find suitable, cheaper materials to use for the catalyst materials and it should be only a matter of time before a suitable material or alloy is found to replace platinum in the fuel cell's construction.
Needless to say - a fuel cell solution is not quite there yet but it is on it's way!

There also exists a fuel cell which utilizes Methanol as the fuel source - of course this is probably not the way to go as Methanol is rather toxic and is produced from fossil fuels commercially - not my preferred choice of a deep green system power source and the CO2 released is "new" greenhouse gas as apposed to the CO2 released from Ethanol, which is "recycled".

The more exotic fuel cell systems are basically out of reach for most experimenters so I will not go into them any further - if you are interesting in fuel cell technologies as a whole or are looking for information about them just use Wikipedia and do a search for "fuel cells" - there is all sorts of good, easy to understand information there along with links to more information than a person can read in a lifetime!


There is a great deal touted about the virtues of wind power. Of course you need to live in an area that has wind blowing most of the time to gain an advantage in using wind power! The part of the United States in which I currently reside normally does not have wind speeds great enough to utilize wind power as a viable solution. Needless to say this is one form of alternate energy I can not tap into easily so will not go any further into it.

My Final Solution:

From the previous information I have posted here, which is just a small fraction of the information I have been gathering for the last few months I decided my best option is to use a solar solution for my power needs. Living in Florida has the advantage of a fairly good solar supply most of the time - not as good as living out in the western part of the United States in the desert but over all it is fair. Living at a lower latitude also has the advantage of being able to place the solar array on the roof of the house and not requiring elaborate solar array mounts to raise the angle of the solar array to match the latitude (best for capturing the most amount of energy).

The use of a solar array also reduces the complexity of storing the collected energy for use during "dark" periods as apposed to fuel cell technologies which require storing either highly flammable Hydrogen gas or some form of liquid fuel - such as Ethanol or Methanol. The only additional components for the solar array system is a storage battery and a power regulator to control the charging of the storage battery by the solar array panel. The power regulator can be either complex or simple, depending on the bells and whistles you are looking for. Some allow remote connection by a computer to monitor the system but in my case I only need something to efficiently regulate the solar panel output so as not to overcharge the storage battery. One such regulator is produced by SunGuard and meets all of my requirements. If you are interested you can find more information here: Regulator

The solar array I finally settled on is a thin-film design - in other words the active material is deposited on a thin sheet of glass instead of being built up on a silicon wafer. I chose this design for the simple reason I found a 20-Watt rated solar array for $90 instead of the usual $160+ price you normally find for a 20-Watt solar array! My source is: Electronic Goldmine which is an electronics website for parts. Now - this is just the solar array and needs to be mounted to a support frame. I leave it to you to perform this as there are all sorts of methods to mount the solar array - just be aware it is thin glass and as such needs the proper support to keep it from breaking! By my estimate it is about 1/16th of an inch thick. When I built my mount I used a 3/4-inch X 1-Foot X 3-Foot board as the backing material and a 1/16th inch think piece of glass over the top to protect the actual solar array. The additional glass cover reduced the effective sunlight conversion by about 3% but the tradeoff in protecting the solar array was worth it in my opinion.

Power Storage:

Since the power for the computer system will be supplied from a solar cell and the location where I live (and most people on the planet for that matter) is not in direct sunlight 24-hours I need a method to "save" the power supplied by the solar panel. We have the technology! It is called a lead-acid storage cell array (Lead-Acid Battery by any other name). Kidding aside I decided to use a deep-cycle lead-acid battery as the storage medium for several reasons:

Price - a deep-cycle lead-acid batter handles deeper discharge rates much better than the normal lead-acid battery you find in a car or truck. It is designed (uses a higher purity lead and the plates are thicker) to supply current for long durations without causing issues that would occur with a normal automotive lead-acid battery. The biggest issue is the life of the battery itself. Automotive lead-acid batteries are designed to handle the vibration generated in an automobile from such sources as the engine, potholes, out of balance tires and so on. In order to do this the lead contains some impurities to make it harder than it would be otherwise. This "hardening" of the lead allows the battery to survive much better than it would otherwise - at a price. Since there are impurities in the lead they don't add to the total storage capacity of the battery. The impurities also cause other issues when the battery is discharged close to the maximum of it's total capacity - as in the form of conductive material that accumulates in the bottom of each battery cell. Once the accumulation reaches the bottom of the lead plates within the cell they "short" out and will no longer hold a charge. This can cause all sorts of nasty things to occur - even to the point where the battery cell generates enough heat to cause a fire! Not a good thing! A second point is the actual plate construction. Automotive batteries are designed to supply high cranking current to start the engine. In order to do this they are constructed more like a sponge - to increase the total surface area of the plate. The larger the surface area the more instantaneous current can be obtained. The lead forming the "spongy" material is like a woven mesh and is small in diameter. When you deep discharge this type of battery the "spongy" lead gets consumed due to the electrochemical process of releasing the electrical current and some falls to the bottom of the cell as well.
Now - you are probably wondering why I said "price" as the heading here - that is because if you use an automotive battery you will go through around three or more of them as you would using a battery designed for this application. The total "cost" of the power storage system is actually less using the deep-discharge lead-acid battery over the life of the storage system than the total cost using automotive battery technology!

Total Usable Energy Capacity - Automotive batteries have one job to perform and that is powering the cranking system of the automobile to start the engine. They are designed to supply large currents for a short period of time and not designed for deep-cycle operation. Deep-cycle batteries are designed to allow up to 80% discharge whereas an automotive duty battery usually will not tolerate such "deep discharge cycles" without failing prematurely. Once the engine is running the Alternator takes over powering the electrical system in the car and also re-charges the battery back to it's full charge for the next cranking exercise. The automotive lead-acid battery is not designed to output current continuously for long periods of time. They are designed to supply the cranking current needed to start the automobile. This normally is around a couple of hundred amperes of current for a short amount of time. If you ever have attempted to start a flooding engine you know you can not keep on cranking without the battery getting low pretty quickly! When you try to draw low current levels for long periods of time the battery voltage drops quicker than with a deep-discharge lead-acid battery.

Total recharge cycles - An automotive battery does not handle being discharged to it's lowest usable level then recharged very well. The impurities within the lead that harden the lead is the biggest culprit of this issue as well as the actual construction of the plates with a "spongy" lead material to increase the total surface area of the plates. A deep discharge lead-acid battery does not suffer from this issue anywhere near as much as an automotive battery because of the high purity of the lead used in it's construction and thicker solid plates. An additional advantage if the high purity lead is the discharge of the battery is more consistant than in the automotive battery and the re-charge cycle tends to be shorter as well given the total surface area of a deep-cycle battery plate is less than in an automotive battery.

If you are interested in the different types of lead-acid batteries a real good website is:
Wind & Sun who have a great FAQ on the subject - a must read if you are looking to use solar technologies for alternate energy!

Tuesday, May 5, 2009

What is Deep Deep Dark Green?

What the heck is a "Deep Deep Dark Green"?

Simple question with a simple answer - a Deep Deep Dark Green is any device that either uses very little power or does not rely on the power grid for it's power! Did I make that up - Not sure but it sure sounds good!

With all the interest in becoming energy independent I thought a good idea would be to design and build a computer system that does not rely on fossil fuels for operation. Using a laptop is not going deep green as you use a power adapter to re-charge the battery pack - guess what, that power adapter is powered from the power company! If you are using a charger designed for an automobile you still are not running deep green as you have to re-charge the car battery and that requires running the engine (which is burning gas)! Nope - you have to think "alternate" energy as the power source - not converting grid power or burning fossil fuel for power... think "fuel cell, wind power, and/or solar power sources! Now - I know what you are thinking! Fuel cells? That requires a "fuel" and an oxidizer (usually oxygen) to "create" an electrical current! Yes - that is a true statement, but there are ways to generate hydrogen without requiring the burning of fossil fuels (that is where wind and solar power sources come to play).

As one would guess this task is really not as easy as you might think. The reasons for this statement are many but I will try to condense them to something reasonable to make it easier to understand. From understanding power sources to ways to make the computer system more efficient are the subject of this blog! Even the choice of operating system for the computer comes into play.

Most of today's modern personal computers have a great deal of capability built into them. Home computers of today actually have more computing power than most mainframes did in the 1980s and with the advances being made in computer technologies you can now buy a home computer that will run rings around some 1990's Mainframe computers as well! The advances in electronics miniaturization and the ability to pack more and more transistors in the same space has led to the advent of multicore microprocessors that run at very high speeds - all sitting on your desk or in your laptop!

All of this computing power comes with a price - they are very power hungry machines! Most hi-end home computers have power supplies in them that consume around 550 - 750 Watts of electrical energy when they are running at full capacity and around 100-watts sitting idle. This can be compared to running 7 to 10 75-Watt light bulbs for the same amount of time as the computer is turned on and being used. If you use the computer system a great deal the cost of running it can be surprising! For example - if you use your computer for 3-hours a day and it consumes 300-watts on average during use then you will have used 27-Kilowatts of electricity over a 30-day period. 27-Kilowatts may not sound like too much as most homes use around 10,656 kilowatt-hours (kWh) per year (Ref: ). My example would use around 900 Kilowatt-hours a year to run the computer or about 8.4% of the national average for a average home. If you leave the computer running all the time then the numbers definitely increase! Not only would you use 900-Kilowatt-hours of electricity during your sessions on the computer but an additional 63-Kilowatt-hours a month ( 756 Kilowatt-hours a year) when the machine is idling at 100-watts. This translates to about 15.5% of the total yearly power used in an average home!

If you own a gaming machine it probably has at least a 750-Watt power supply and some now come with 1000-Watt (that is a kilowatt by the way) power supply to power the multi-video cards needed for hi-end gaming software! What this means is the gaming machines (PCs) use even more power than a normal home computer. One thing though - they sure have some real pretty graphics capabilities! Of course all that power must be going somewhere and that somewhere is in the form of heat. They not only generate a good deal of heat (which you have to get rid of or enjoy a dry sauna unless you live above the arctic circle) but adds to your carbon footprint (love that term - still - have not found any carbon footprints on the sidewalk yet) or the amount of carbon released into the atmosphere by the power company supplying the power to run your computer.

I wanted to break away from the "more power" cycle for my personal computer so I started looking into "alternative" computing systems. Just to be fair I own one of the hi-end home computer systems which contains two very power-hungry video cards, two dual-core processors (total of four processor cores), very high-speed memory (also very power-hungry) and massive storage capacity - in a nutshell it is not a machine I want to have running all the time! Given the configuration of my "home" system I burn through about 700-watt/hour of electricity and given today's cost for grid power that has become unacceptable to me.

In today's world of miniaturization there exist computer systems most people are not aware of with some impressive capabilities but are very small in size. These computer systems are built for the "embedded" computing market so the normal consumer never runs across the devices except when they are built into something else. Some examples would be your cell-phone (ever wonder how they can do all the things they do?), a PDA device (which now seems to be a cell-phone as well), modern medical equipment such as is found in most emergency rooms to monitor patients or in the hospital rooms to monitor things such as blood pressure, heart-rate and so on, car navigation and entertainment systems, portable GPS devices and the list goes on. What most people do not realize is the capabilities of these "embedded" computers has reached the level of home computer capabilities of machine built just 4 or 5 years ago but with a much smaller physical size and very low power requirements!

In thinking about the power waste of my home system I hit upon the idea of looking into an alternative method of accessing information and email, things I do every day but don't necessarily require the capabilities of my home computer system. To this end I have created a "partial list" of things I would want a general use home computer system to perform. Part of my criteria for a home computing system are:

  1. Capable of browsing the Internet with relative ease - what good is using a computer to view web pages if it is a hassle to do so? This includes the capability to view Flash-based and Java applet based websites along with the normal video streaming technologies used to display video.

  2. Capable of getting and sending my email, again with relative ease. It should have the capability of accessing email using several different protocols to allow the access to multiple email accounts on different systems (personally I have 7 distinct email accounts - and need each one too).

  3. It should have plenty of storage space to allow me to store documents, pictures and music. Given the power requirements of most physical hard drives I am using solid-state drives - about 2 -watts of power total per drive. Even the 2.5-inch hard drives draw over twice that much power and are subject to mechanical failure whereas a solid-state drive has no moving parts so is not subject to mechanical failure (bump it while running and it does not crash!).

  4. It should be capable of playing music. It should be capable of displaying my pictures in different formats. I realize this is more of an "applications" requirement but for audio and video/picture capability you need the proper hardware so I am including it in my "list".

  5. It should be capable of sending and receiving files so I can load and remove files from storage. This requirement implies the capability to connect the computer to some form of a network.

  6. It should have the capability to connect to my wireless home network with security capabilities. Here is the connectivity alluded to in item number 5. The system should also allow for a method to connect to a wired network as well - not everyone uses wireless networking for one reason or another.

  7. I don't normally play hi-end games so that is not a requirement for me - but it would be a nice thing as I am sure others may want to. I don't expect a system such as I am describing to have the capability of running any hi-end, fast paced games (such as Day of Defeat or other compute-intensive First-person Shooter games). If you want to do gaming at a relatively low energy requirement get a PlayStation-3 or X-Box 360 Gaming console. An added advantage of the PlayStation-3 is the built-in BlueRay player - you can watch movies as well using it as the player. They are built specifically for running hi-end games without using a great deal or electrical power.

  8. It should allow me to use Bluetooth devices such as a keyboard, mouse and headphones to keep the wiring clutter to a minimum. I prefer to use Bluetooth in place of some other "wireless" technologies since it is very prevalent now and my PDA/Phone is Bluetooth capable so I can link to the PDA/Phone for either internet access or to move music/video/data files between the two systems.

  9. It should be small so as not to take up much desk space - if it is capable of being connected to the back of a monitor so much the better!

  10. USB-OTG 2.0 capable - For those of you who are not aware of the OTG part it stands for "On The Go" and is an extension to the USB specification. Basically it allows the USB port to either act as a host or slave port. Connecting a USB device such as a USB keyboard or USB Thumb-Drive to the port will cause the port to act as a Host port. If you want to connect, say, a PDA/Phone with a USB port on it you may want the USB-OTG port to act as a Slave port for the link if you are looking to access the Internet through the PDA/Phone. The PDA/Phone will act as the Host port and allow TCP/IP communications (if configured) between the PDA/Phone's Wireless Network connection and the computer system. (Very handy if you don't have Internet connectivity due to no grid power or fallen trees across the phone lines/cable lines after a Hurricane or Violent Storm (natural disaster).

  11. It should consume no more than 20 watts of power total - monitor and all! Preferably less if possible!

  12. It should not require power from the local power grid!

Wait a minute - did you read that last requirement correctly???

Yes - You DID!!!

I want the system to perform all of the above functions with a power footprint of less than 20 Watts TOTAL and no reliance on the local power grid! The lower the power requirements the better! Not only should it require less than 20-watts total it also must not rely in any way on the local power grid for it's power requirements! This is the reason I call it the Deep Deep Dark Green computer system.


Hehehe - you decide as you read more about this idea and it's implementation!