The Stirling Engine

A ‘Stirling Engine’ is in the family of heat engines. It is a closed cycle regenerative hot air (or other permanent gas) engine.. Closed cycle means that there is a fixed volume of the ‘working fluid’ in the system. There is no intake, there is no exhaust.

The Stirling engine was first patented in 1816 by Dr. Robert Stirling. The original patent focused more on ‘The Economizer’ which was a heat exchange unit that saw primary interest for use as the first incarnation of the solar water heater.

Originally the Stirling engine was developed by Robert Stirling and his brother James. It resulted in many patents and the first Sterling in commercial use was used to pump water in a quarry in 1818. After more development many patents for various improvements, including pressurization, which directly affected the amount of work or force the engine could produce, came about in 1845. By this time, the power output of this engine had been brought up to the level that it could drive all the machinery at a Dundee iron foundry.

The engine was promoted as being very fuel conserving and was pushed to be a safer alternative to steam engines of the time that had many deadly incidents involve exploding boilers. However because of the heat required and the level of exchange required, coupled with the materials of the day, the Stirling engine could never really give the steam engine serious competition, and by the late 1930’s the Stirling was all but forgotten in mainstream science and industry and only represented in odd toys and small ventilation fans.

Around this time, Philips, the large electrical and electronic manufacturer was seeing to expand its market for radio sets into areas where a power source or supply of batteries was considered unstable. Philips further developed the Stirling engine through World War II and really only achieved commercial success with the ‘reversed Stirling engine’ cryocooler. However Philips did take out quite a few patents and gain a large amount of information about the Stirling engine.

Since the Stirling engine is a closed cycle, it contains a fixed mass of gas called the “working fluid”, most commonly air, hydrogen or helium. In normal operation, the engine is sealed and no gas enters or leaves the engine. No valves are required, unlike other types of piston engines. The Stirling engine, like most heat-engines, cycles through four main processes: cooling, compression, heating and expansion. This is accomplished by moving the gas back and forth between hot and cold heat exchangers. The hot heat exchanger is in thermal contact with an external heat source, e.g. a fuel burner, and the cold heat exchanger being in thermal contact with an external heat sink, e.g. air fins. A change in gas temperature will cause a corresponding change in gas pressure, while the motion of the piston causes the gas to be alternately expanded and compressed.

The gas follows the behavior described by the gas laws which describe how a gas’s pressure, temperature and volume are related. When the gas is heated, because it is in a sealed chamber, the pressure rises and this then acts on the power piston to produce a power stroke. When the gas is cooled the pressure drops and this means that less work needs to be done by the piston to compress the gas on the return stroke, thus yielding a net power output.

When one side of the piston is open to the atmosphere, the operation is slightly different. As the sealed volume of working gas comes in contact with the hot side, it expands, doing work on both the piston and on the atmosphere. When the working gas contacts the cold side, the atmosphere does work on the gas and “compresses” it. Atmospheric pressure, which is greater than the cooled working gas, pushes on the piston.

To summarize, the Stirling engine uses the temperature difference between its hot end and cold end to establish a cycle of a fixed mass of gas expanding and contracting within the engine, thus converting thermal energy into mechanical power. The greater the temperature difference between the hot and cold sources, the greater the potential Carnot cycle efficiency.

Pros and Cons of Stirling Engines


  • They can run directly on any available heat source, not just one produced by combustion, so they can be employed to run on heat from solar, geothermal, biological, nuclear sources or waste heat from any industrial process.

  • A continuous combustion process can be used to supply heat, so most types of emissions can be greatly reduced.

  • Most types of Stirling engines have the bearing and seals on the cool side of the engine; consequently, they require less lubricant and last significantly longer between overhauls than other reciprocating engine types.

  • The engine mechanisms are in some ways simpler than other types of reciprocating engine types, i.e. no valves are needed, and the fuel burner system can be relatively simple.

  • A Stirling engine uses a single-phase working fluid which maintains an internal pressure close to the design pressure, and thus for a properly designed system the risk of explosion is relatively low. In comparison, a steam engine uses a two-phase gas/liquid working fluid, so a faulty relief valve can cause an over-pressure condition and a potentially dangerous explosion.

  • In some cases, low operating pressure allows the use of lightweight cylinders.

  • They can be built to run very quietly and without an air supply, for air-independent propulsion use in submarines or in space.

  • They start easily (albeit slowly, after a warm-up period) and run more efficiently in cold weather, in contrast to the internal combustion which starts quickly in warm weather, but not in cold weather.

  • A Stirling engine used for pumping water can be configured so that the pumped water cools the compression space. This is, of course, most effective when pumping cold water.

  • They are extremely flexible. They can be used as CHP (Combined Heat and Power) in the winter and as coolers in summers.

  • Waste heat is relatively easily harvested (compared to waste heat from an internal combustion engine) making Stirling engines useful for dual-output heat and power systems


Power and torque issues

  • Stirling engines, especially those that run on small temperature differentials, are quite large for the amount of power that they produce (i.e. they have low specific power). This is primarily due to the low heat transfer coefficient of gaseous convection which limits the heat flux that can be attained in an internal heat exchanger to about 4 – 20 W/(m*K). This makes it very challenging for the engine designer to transfer heat into and out of the working gas. Increasing the temperature differential and/or pressure allows Stirling engines to produce more power, assuming the heat exchangers are designed for the increased heat load, and can deliver the convected heat flux necessary.

  • A Stirling engine cannot start instantly; it literally needs to “warm up”. This is true of all external combustion engines, but the warm up time may be shorter for Stirlings than for others of this type such as steam engines. Stirling engines are best used as constant speed engines.

  • Power output of a Stirling tends to be constant and to adjust it can sometimes require careful design and additional mechanisms. Typically, changes in output are achieved by varying the displacement of the engine (often through use of a swashplate crankshaft arrangement), or by changing the quantity of working fluid, or by altering the piston/displacer phase angle, or in some cases simply by altering the engine load. This property is less of a drawback in hybrid electric propulsion or “base load” utility generation where constant power output is actually desirable.

Gas Choice Issues

  • Hydrogen’s low viscosity, high thermal conductivity and specific heat make it the most efficient working gas, in terms of thermodynamics and fluid dynamics, to use in a Stirling engine. However, given the high diffusion rate associated with this low molecular weight gas, hydrogen will leak through solid metal, thus it is very difficult to maintain pressure inside the engine for any length of time without replacement of the gas. Typically, auxiliary systems need to be added to maintain the proper quantity of working fluid. These systems can be a gas storage bottle or a gas generator. Hydrogen can be generated either by electrolysis of water, or by the reaction of acid on metal. Hydrogen can also cause the embrittlement of metals. Hydrogen is also a very flammable gas, while helium is inert.

  • Most technically advanced Stirling engines, like those developed for United States government labs, use helium as the working gas, because it functions close to the efficiency and power density of hydrogen with fewer of the material containment issues. Helium is relatively expensive, and must be supplied by bottled gas. One test showed hydrogen to be 5% absolutely (24% relatively) more efficient than helium in the GPU-3 Stirling engine.[14]

  • Some engines use air or nitrogen as the working fluid. These gases are less thermodynamically efficient but they minimize the problems of gas containment and supply. The use of Compressed air in contact with flammable materials or substances such as lubricating oil, introduces an explosion hazard, because compressed air contains a high partial pressure of oxygen. However, oxygen can be removed from air through an oxidation reaction, or bottled nitrogen can be used.

Size and Cost Issues

  • Stirling engine designs require heat exchangers for heat input and for heat output, and these must contain the pressure of the working fluid, where the pressure is proportional to the engine power output. In addition, the expansion-side heat exchanger is often at very high temperature, so the materials must resist the corrosive effects of the heat source, and have low creep (deformation). Typically these material requirements substantially increase the cost of the engine. The materials and assembly costs for a high temperature heat exchanger typically accounts for 40% of the total engine cost. (Hargraves)

  • All thermodynamic cycles require large temperature differentials for efficient operation; however, in an external combustion engine, the heater temperature always equals or exceeds the expansion temperature. This means that the metallurgical requirements for the heater material are very demanding. This is similar to a Gas turbine, but is in contrast to a Otto engine or Diesel engine, where the expansion temperature can far exceed the metallurgical limit of the engine materials, because the input heat-source is not conducted through the engine; so the engine materials operate closer to the average temperature of the working gas.

  • Dissipation of waste heat is especially complicated because the coolant temperature is kept as low as possible to maximize thermal efficiency. This increases the size of the radiators, which can make packaging difficult. Along with materials cost, this has been one of the factors limiting the adoption of Stirling engines as automotive prime movers. However, for other applications high power density is not required, such as Ship propulsion, and stationary microgeneration systems using combined heat and power (CHP).[13]

    There are many possible uses for the Stirling design. More research and devolopment will help move the technology along.

Source by Michael Motley

How to Find a Free Deep Cycle Battery

Maybe you are looking for a set of deep cycle batteries to replace your old ones. Maybe you want to find a free deep cycle battery to try desulfating it so it is near new and then try to sell it. Some people are even getting a large deep cycle battery and removing all the good cells so they can sell them for renewable energy systems.

A home renewable energy system using wind or solar needs anywhere from 12 volts to 48 volts. Each cell from a deep cycle battery is about 2 volts, so it takes 6 cells for every 12 volt section. If you were to buy these cells new, then they cost between $300 – $600 each. A small 12 volt 650 amp hour battery setup would cost about $1,800 for the forklift battery cells. You could use golf cart batteries at about $80 each and 220 amp hours each. It would take 6 of them to do it and it would cost about $500.

Here is the kicker, though. A deep cycle battery cell from a fork lift battery lasts about 4 times as long as a golf cart battery. You could refurbish the cells out of the forklift battery and sell them for $100 each. They would easily last twice as long (or more) as the golf cart batteries and you could make a handsome profit for doing it.

My first pair of forklift batteries that I got for free happened to be Yuasa batteries, but all kinds are available. What I discovered is that usually most cells in the battery are still pretty good. Usually it is one or two bad cells. Most places just have their batteries picked up for recycling when the battery doesn’t make it though a 8 hour shift. These two batteries to the left had all good cells except 3 of them. There are 12 cells in each (these are 24 volt, 700 amphour), so that gives me 21 good cells.

So, if you’re selling these cells, you can make up to $2,100 profit. If you keep them for your own use (which is what I did), then you could make 3 banks of 12 volts at 600 amp hours each, or 12 volts at 1800 amp hours total. I say 600 amp hours instead of 700 because even after checking fluid levels and using my homemade desulfator, the amp hour capacity never gets up to brand new levels. But you can usually get 70% to 90% capacity, especially if you remove the bad cells. In the above example, you will use 18 of the cells total, leaving 3 good ones. You will probably have to just recycle those last 3 cells.

To get the batteries free, just call around to anyplace with a warehouse that uses forklifts. The first two in the picture above were picked up at the local post office main hub. You could just go through the yellow pages. Ask if they use electric forklifts, if so, do they plan on replacing their batteries in the near future. If you have a pickup truck, I would stick with the 12 or 24 volt ones. You can tell them that you can take them off their hands for free and that you will sign any environmental forms that they require.

There is another way to get forklift batteries but it costs a little money. Just look in the phone book and find the local forklift company. Almost all of them sell new batteries and deliver them as well. But they will also come and pickup old forklift batteries to recycle. They always have several sitting around. On Vancouver Island in Canada, the local company gets about 3 cents per pound from the local recycler. I can go to the forklift company and pick the best of the used ones and pay by the pound. A 24 volt like the one above weighs about 1,100 pounds or so. I can move those with a engine hoist and my V6 nissan pickup. Any bigger and you need other arrangements. They will also deliver the batteries to my home and plop them wherever I like. At 3 cents a pound, I could pay $66 for the two batteries in the above picture. Then they would charge about $70 per hour for the delivery. Let’s say, worse case, it cost 2 hours in labor, that is $206 for both batteries. If I sell individual cells in 12 volt groups, then I could sell 18 of them (3 cells were bad) and make $1,800. That gives me $1,600 profit. Not bad.

Source by R. C. Lewis

Advantages of a Perpetual Motion Machine

As the name may suggest, a perpetual motion machine is a device used to provide cost free energy and if used well, it can be available for all human beings. Well, to begin with, it’s important to understand that it’s very difficult to understand, rather to conceptualize a perpetual motion machine because it can take decades to create it. Still on point, there are very many contradicting theories as to how one can come up with a perpetual motion machine because in real sense, it’s very difficult, near impossible. However, thanks to advancement in technology and various scientific breakthroughs such as using magnets as the main material for this machine, people have started conceptualizing the idea in their minds.

There are numerous advantages of a perpetual motion machine in any given home. First off, although it’s not particularly visually appealing hence cannot be perceived as an aesthetic value in a home, it can still be used as a decoration and a source of pride for many, thanks to its design. It would be a source of pride as homeowners will be able to display their scientific knowledge and provide a sense of speculation to the visitors who know nothing about its functioning. It would be a piece of technology that will provide endless hours of conversation as the homeowner tries to explain the mechanism behind it, trying to explain the endless continuous motion. The main merit however that a perpetual motion machine provides lies primarily in the idea that it possesses a life changing functionality and not necessarily in its aesthetic or decorative aspect, although they cannot go unmentioned.

As a source of power in the house, its long term advantages are numerous particularly when it’s full potential is utilized well in a way that will emit even a portion of its real potential. However, the device has been an object of a lot of research as well as a source of controversy as to whether or not there is a possibility to come up with such a machine. But with the tangible evidence available at hand, it’s believed that a perpetual motion machine is certainly able to be used as an alternative source of power just like a wind energy thermal, a solar energy and various other alternative energies that the human species currently utilizes. With the current findings at hand, it’s believed that this type of alternative energy will be the cheapest source of energy when one factors in the cost of having it and the amount of work required to maintain it properly.

A perpetual motion machine is said to emit energy at nearly no cost at all. In other words, scientists are saying that this source of power will be affordable to many and one wouldn’t be required to invest a lot of money to get energy from it. While a few decades ago this technology was just a legend, thanks to the efforts of scientists and advancement in technology, the legend is no more a legend but a reality. Magnets have been used to make this legend a reality, while the current technology provides the backup necessary to turn the motion created into usable energy. As per the look of things, a perpetual motion machine is arguably the best technological breakthrough in regards to alternative energy in the current generation, all with the aim of making life easier and simpler.

Source by Ted Wilson

No Deposit Texas Electric Service

A few electricity providers offer some alternative ways for low or no credit Texas energy consumers to have their electric service turned on without having to fork over the equivalent of 1 months rent for many of these Texas electricity customers. You will hear three different options when it comes to low or no deposit electric service. These options are post paid, no deposit guaranteed, and prepaid electricity service. The post paid energy service is what most people have. You simply are billed for the electricity service you used the previous month and you pay that amount. The problem is if you have bad credit most electricity companies in Texas are going to want a deposit.

Post paid electricity service is the ideal situation because you get billed for your usage after you have used it and you pay on the designated due date. This gives you time to read your bill and study how much energy you have used. You can then pay your bill online or by mail and maybe work on using less next month. The post paid electric service plans are usually cheaper then prepaid electric service. Many post paid plans available are fixed rates. These rates have been locked in for a 6 month, 1 year or 2 year electricity price. When signing up on a fixed rate you know exactly what you will be charged for electric service each and every month because the price does not change. The problem with trying to get on a fixed rate on a post paid service is that most providers will need a deposit if you have no credit or just bad credit. Many consumers have to skip this choice because the deposit amount is way outside what they can afford to pay.

There is another Texas electricity service choice called prepaid electricity. This type of service requires the Texas electric provider to come out to your home or apartment premises and install their own meter. This electricity meter allows you to prepay for electric service in advance. The main issue with prepaid electricity service in Texas is that many customers have complained that their electric service was cut off prematurely for being a little late on prepaying for their service. The Texas government requires that Texas electricity companies give the energy consumer fair warning before turning off their electric service but many consumers have complained that this is not what happens. The PUCT is supposed to fine the energy companies that break the rules but many consumers do not file the appropriate evidence that proves to the state that the Texas electricity company is not following the consumer protection laws. It is up to the consumer that was wronged to call the Public Utility Commission of Texas and explain what the Texas energy company has done to them in order for the state to take appropriate action.

The final Texas electricity service choice for low income or no credit customers is the no deposit guaranteed option. For those Texas energy consumers that have had their credit dinged by some late payments or a credit card that was charged off there is still an option for them. The no deposit guaranteed choice requires that the Texas energy consumer have a valid credit card. As long as a valid credit card is available there is a second chance for someone who needs to get Texas electric service turned on right away without having to worry about how they are going to come up with $200 – $1000 for a deposit. The way the no deposit plan works is the consumer pays a slightly higher electricity service rate the first 3 months they are with the no deposit Texas electric company. After the customer has paid on time the first 3 months the electric company will proactively lower the energy price to the lowest available electric rate they offer in Texas. This gives the no credit or bad credit customer a second chance of reestablishing themselves as a responsible customer who pays their bill on time. Instead of penalizing the customer for their mistakes in the past this company rewards the customer provided they pay their bill on time the first 3 months.

When choosing between post paid, prepaid and no deposit guaranteed electricity service in Texas there are only a few things to consider. The decision is a no-brainer for most people in a bad or no credit situation because most people want as little headache with their energy company as possible while still being given the chance to sign up for affordable energy service. Prepaid electricity is not the right choice for most people because the rate is usually much higher then other electric companies and the track record of these energy companies turning off electric service prematurely is pretty high. Post paid electricity service is not an option for most bad credit risk customers because they would have to come up with a very high deposit amount just to get electric service turned on in their name. No deposit guaranteed Texas electricity service becomes the best option for someone looking to sign up and order electric service in their name and completely avoid the high deposit scenario. The electricity service gets turned on fast and the headaches associated with shopping for an electric provider that will not charge a deposit are over. No Deposit Texas Electricity service is considered post paid electricity but without the need for a deposit. For most bad or no credit customers in Texas this represents the best possible option until their credit improves. Since a valid credit card is required some bad credit customers who do not have a credit card must sign up on a prepaid electric service plan because there are no other options then this if the customers credit is bad, they have no credit card, and they cannot afford to pay a deposit.

Source by Ron Giles

Benefits Of Future Technology

In this write up, the readers will get information on future technology and learn to what extent modern technology has been developed to assist the growth of human civilization.

Technology of the Future would be more sophisticated and user friendly. The rapid technological advancement will make technology more convenient and usable. New technology should be used for the benefit of the society. Now, it is better to say to what extent science and technology have been acceptable to the present generation. In comparison to conventional devices and equipment, future technology news states that ultramodern devices are more workable and powerful in their functionality. According to scientists and researchers, modern technology can make modification and upgrading of common things for their proper usage applying modern methods. The world will be more glamorous and attractive with newer technology and without any trace of carbon footprint.

If you check future technology news, you will find that there are newly launched products and technical accessories which have multifunctional features. For instance, recently Kevin Cheng invented Solar Planter which protects the natural green resources of nature. Plants will be highly protected using the Solar Planter which artificially creates solar energy to preserve green plants in a perfect way. The device is also equipped with powerful exhaust fans to clean out stagnant air from within the Solar Planter. Air will be circulated well inside the planter for the safe keeping of trees and plants. The Solar Planter is also energy efficient and environment friendly. According to future technology news nature will be completely protected from pollution using these new technologies as it will not produce any lethal or hazardous chemical solvents or gasoline products into the air.

In the sphere of the telecommunication, future and modern technology is very powerful and has contributed extensively for the betterment of the communication system. The invention of the humanoid robot is a burning example. Future technology news say that this robotic structure will be sent to out of the planet to strengthen the communication system. Experiments are still going on the upgrade of this robot.

Concept Cloud Blackberry is a sophisticated mobile phone which is both eco friendly and pollution free. This mobile is activated by liquid fuel which doesn’t disturb the peace of nature. Future technology will bring a lot more inventions and accessories to upgrade human lifestyles. The scientists believe that modern science is very effective to make the world green. Future technology must be more user friendly and should not hamper the natural growth of the human race. It must not disturb nature or the society.

Science is a boon and man needs to utilize this for the overall development of the world. Future technology these days not concentrated only on the benefit of humans. Scientists are trying to create technology that will be beneficial to the earth as well.

Conclusion: To get updated information on latest technology, you can check future technology news on the Internet. There are new discoveries and upgrades available every day.

Source by Ruth Caldon

3 Darrieus Wind Turbine Facts You’ll Want to Know

When it comes to green energy alternatives wind turbines are certainly up there with solar energy and hydropower generators as being one of the most attractive green energy options. In the paragraphs to follow I’m going to be sharing with you some Darrieus wind turbine facts you may not be aware of, including important distinctions between the popular and iconic propeller driven wind turbines and the somewhat mysterious Darrieus types. These vertical axis wind turbines (VAWT’s for short) can very easily be seen as a superior design, let’s take a look at exactly why that is.

Low Wind Efficiency

When considering which type of wind turbine to go for one obvious factor stands out and that’s efficiency. After all the whole point here is to generate as much electricity as possible and remarkably this is where the Darrieus type of wind turbine really shines. Typical propeller designs are optimised to function best when the wind direction is headed straight into the front of the propeller which means when the wind changes (as it does on a moment by moment basis) the propeller stops spinning or at best severely reduces its rotation speed until the wind once again hits that sweet spot, which often must be achieved by rotating the propeller to face into the wind.

The Darrieus wind turbine however has a number of unique characteristics which enhance its performance, even under low wind conditions. The first being the unique shape of the aerofoil blades, curved out and shaped just like that of an aeroplanes wing, which when wind is applied produces high pressure on the inner side of the blade and low pressure on the outer side which then propels the blades and shaft around in a circular motion. The second and probably most distinctive attribute of this type of wind turbine is that while many have only two blades they typically can have three to four blades also, which means regardless of which direction the wind is blowing the shaft will continue to turn so long as there is wind. Even in low wind conditions the Darrieus wind turbines will keep spinning, only stopping when the wind comes to a complete stop.

Residential Friendliness

In a world where we’re trying to become more energy independent, sources of renewable green energy must also be practical… and practicality starts at home. When talking about wind turbines Darrieus versions are well known for being super quiet, which is crucial considering they are typically active day and night and I’m sure the last thing you want are complaining neighbours. So it’s important. They are well balanced and because they vibrate less they simply don’t produce as much noise.

A common problem often associated with wind turbines is that of birds flying into them and meeting their maker. This is obviously something to avoid and in this case, it’s something that can be avoid with great success. Many owners of Darrieus wind turbines report of having no such issues with birds flying into them, as opposed to propeller type wind turbines which have an unfortunate track record of causing harm to birds. This is likely due to the fact that because of the way the Darrieus turbines are designed, they appear like more of a solid object to birds and they tend to keep away from them.

Take Your Pick

There are a number of different designs which can be classed as Darrieus wind turbines. They share many similarities, however they also share key differences each with their own advantages. Giromills or H-bars as they are otherwise known are a “less efficient” design in normal conditions compared to the Darrieus designs, however often work well and in fact better in more turbulent wind conditions. They’re also more affordable.

Cycloturbines are an interesting creation as each blade is mounted so that it can rotate around its own vertical axis. This allows for the blades to be pitched for the optimum angle of attack which results in improved performance in a variety of wind conditions. The ability to adapt makes this design easily the most effective and most powerful Darrieus wind turbines available because it can produce more consistent torque. It’s also able to self start much easier because of the ability to pitch the blades. The only real downside is the complexity and added weight and cost of the pitch mechanism.

And finally the helical design is well known for it’s ability to spread the torque evenly over the entire rotation, which prevents what could otherwise be destructive pulsations, especially in turbulent conditions. These are often smaller units making them a great choice in residential areas.

All in all, nothing is perfect. Green energy has always been a challenging field, especially when competing with the dirty forms of energy we as a society have become so dependent upon. This of course is not a comprehensive list of pro’s and con’s, however it was never mean’t to be. It’s designed to get you thinking and considering Darrieus wind turbines as a viable green energy alternative.

The great thing about green energy technologies such as these (and a huge advantage over polluting alternatives) is that once you’ve set them up, they just run and run and run. You always need more coal, more oil, more “stuff” to break down, burn, etc.

But with wind power, it-just-works!

Source by Daniel Birch

Introduction to Battery Chargers

Battery chargers vary a great deal in intelligence, the types of batteries they can charge, how they maintain batteries, and how long they take to charge. As batteries are such a big investment when it comes to off grid solar power systems, it’s important to get the right one for your off grid solar power system. 

A general rule of thumb is to charge a battery at about 10% of  its amp hour capacity. For example, and 80Ah deep cycle battery should be changed at a rate of about 8A.

Different types of batteries require different charging regimes. For example, SLA (sealed lead acid), AGM (absorbent glass matt) and gel batteries are traditionally charged at a lower voltage than flooded lead acid batteries. This varies depending on the manufacturer and you should always check what charging voltage is required before you buy batteries and a battery charger.

Types of battery chargers

A simple charger works by providing a constant DC power to the battery. A simple charger will not alter its output based on time or the charge on the battery. These type of battery chargers are usually cheap, but there is a trade-off in quality. Typically, a simple charger takes far longer to charge a battery, and a battery left in a simple charger for too long will be severely damaged by over-charging.

Timer based chargers operate much like a simple charger, but (as the name would suggest) they operate on a timer. The timing  would be set for a particular battery and then left. However, if batteries of lower capacity were charged they would be then overcharged and if batteries of higher capacity were charged they would be only partly charged. Timer based chargers also have the drawback that charging batteries that were not fully discharged, even if those batteries were of the correct capacity for the particular timed charger, would result in over-charging.

Battery charger output current depends upon the battery’s state. An intelligent charger may monitor the battery’s voltage, temperature and/or time under charge to determine the optimum charge current at that instant. Charging is terminated when a combination of the voltage, temperature and/or time indicates that the battery is fully charged. In a sense, the batteries tell the charger when they are full.

Some chargers use pulse technology or pulse width modulationin which a pulse is fed to the battery. This DC pulse has a strictly controlled rise time, shape, pulse width, frequency and amplitude. This technology is said to work with any size, voltage, capacity or chemistry of batteries, including automotive and valve-regulated batteries. Most good quality chargers and charge controller use this kind of technology.

Selecting the right charger

As with any component of a solar power system, it’s always best to consult with a battery expert first before purchasing to ensure you’re getting a charger suited to your particular set up. While all chargers work well off a mains power supply, you’ll likely be using yours in conjunction with a generator, so check that the charger you’re interested in is up to the task – some just refuse to function properly in this application.

Source by Michael Bloch

What Radiant Energy Is and How You Can Use It to Power Your Home

Radiant energy is a wonderful source of power. We use it in our daily lives from listening to the radio and talking on our cellphones and much more. It envelops the atmosphere from day to day, year to year, 24/7. The supply of this energy never runs out and only gets bigger every year.

But what is radiant energy, anyway? Radiant energy is simply the forms of electromagnetic waves that collide in our electro sphere. What does that mean? Well it’s quite simple really. They are waves of energy and radiation that we cannot see with our eyes. Because they have different wavelengths there are different types of waves. For example. one such wave could be an x-ray. You probably have been to a hospital sometime in your life. If you have had a broken bone in your body you probably would have had an x-ray checkup with a radiologist.

If radiant energy is common, why don’t we use it? But we already do. Like I said before we use it to power our cellphone signals. our radio towers, and even our microwaves. However when I refer to this energy, I am referring to a different use of this energy. Instead of using it to directly power certain appliances we can use an energy generator to power our appliances. That’s because radiant energy is in essence a form of energy. By converting that energy (in the form of waves) to electricity, much like solar panels do, we can power our homes with it.

How can we use radiant energy to power our homes? In order to convert the energy into a usable form of electricity we will need a specific generator than can use this power. They are called radiant energy generators. These generators sort through the different waves of energy in the air, or more precisely the atmosphere, and convert it into electricity. Some waves cannot be converted and that’s why it sorts through the different frequencies that are compatible.

Where can we get such a thing? The easiest place to get it would be from a company who specializes in these kind of plans. Of course they would only be large-scale archetypes and not actual working models. Currently energy efficiency labs are only focusing their r&d (research and development) in large-scale versions of radiant energy generators. It’s mainly because these small generators are hard to upscale after a few upgrades. Small-scale radiant energy generators are much easier to build though and also happen to be affordable, if you can find the schematics for it. I have actually come across and interesting site that claims to have plans for a radiant energy generator. I was a bit skeptical though, but I decided to check it out. The plans were called ” Sky 4 Energy “. I spent my spare time in the week building it and the results were fantastic. I would tell you more but I already wrote the results in my review site where I objectively reviewed several popular energy generator plans similar to this one.

Source by Tim Jametson

Prepaid and Postpaid System for Electricity

Consumers of electricity these days now have the option on having their electricity put on prepaid or postpaid plans. Prepaid plan on electricity is where consumers deposit first or pay in advance to be able to use electricity while postpaid plan is when a consumer pays for his or her electricity after using it.

How does a prepaid electricity system work?

Mainly, consumers must first purchase a card that has special numbers on it that can be loaded by credits that will then enable them to use electricity, depending on the credits that was loaded. For them to use more electricity they can just simply load their accounts again and by loading their accounts regularly, they also eliminate the possibility of being disconnected from the electric company. In some places, loading an account directly is impossible, what must be done is for them to go to the electric company’s billing center and pay a cashier who will then load credits onto their accounts giving them the electricity supply that they can then use.

How does a postpaid electricity system work?

A postpaid electricity system is what is commonly used all over the world in terms of electricity usage and electrical bills. A meter is installed that will then measure the usage of electricity that has been used in a household or building. The consumers will then be billed on a monthly basis. If an instance like a consumer was not able to pay his or her bills, then that person will be disconnected from the system and will no longer be able to use electricity.

Advantages and disadvantages

Of course like any other system, there is always an advantage and a disadvantage. The advantage for having a prepaid system is that the consumers will have control as to when they would want to use electricity and will never have to pay late on bills. The disadvantage in using a prepaid system is that when a possibility like consumers having to forget to load their accounts, they will not have any electricity to use at home and that can be very inconvenient. While postpaid system however, guarantees that consumers always have electricity supplies except of course during blackouts.

And because of the meter that was installed and being used to measure the consumer’s electricity usage, personnel from the electric company will come on a regular basis to check the amount of electricity that the consumers have used thus eliminating the effort on checking their own meter reading. The disadvantage of postpaid systems is that it requires an expensive amount of deposit. When deciding to terminate a customer relationship from the electric company, the refund that the company will give back takes long enough.

Source by Gerardo Burns

Fossil Fuels and Classifications


Fossil fuel-

· Fuel can be defined as a combustible substance which contains carbon as its main components, which gives large amount of heat on proper burning.

· Carbon can be used economically for domestic and industrial requirements.

· Common example involving wood, charcoal, coal, kerosene, petrol, diesel, producer gas, oil gas, etc.

· During combustion process of a fuel (like coal), the atoms of carbon, hydrogen, etc. combine with oxygen with the simultaneous release of heat at a speedy rate.

· This energy is released due to the “rearrangement of valence elections” in these atoms, resulting in the formation of new compounds like methane and water.


· Coals and petroleum oils are the main source of the fuel; the available quantity of these sources is reduced day by day.

· Fossil fuels are composed by natural resources such as anaerobic decomposition of buried dead organisms.

· The age of the organisms and their resulting fossil fuels is more than millions of years.

· They are non-renewable resources because they take thousands of years to form, and reserves are being decomposed much faster than new ones are being made.

· Its uses and production raise environmental issue.


1. Solid fuel

· Solid fuel is defined as raw materials which are used as a primary fuel to produce energy and provide heating.

· Common example under this category includes wood, charcoal, peat, coal, Hexamine fuel tablets, and pellets made from wood, wheat, rye and other grains.

· It also used in solid fuel rocket technology.

· For creating fire, it has been used.

· Coal is used for firing furnaces, to running steam engines.

· Steam locomotives engines are operated by using wood as fuel.

· In electricity generation, peat and coals are used.

· Due to unsafe levels of toxic emissions, use of some solid fuels is restricted or prohibited in some urban areas.

2. Liquid Fuel

· Liquid fuels are defined as combustible or energy-generating molecules which are used to produce mechanical energy.

· Fumes of these fuels are flammable instead of the fluid.

· Most liquid fuels which are used for various purpose in now days, are derived from petroleum.

Types of liquid fuel:


· It is a by-product of petroleum, contains carbon and hydrogen.

· Gasoline or petrol is produce by hydrocarbon molecules forming aliphatic compounds, or chains of carbons with hydrogen atoms attached.

· Engines that use unleaded gasoline releases fewer hydrocarbons, have fewer combustion chamber deposits, and provide a longer life for spark plugs, exhaust system and carburetors.

· It is generated by distillation of crude oil.

· The desirable liquid is taken out from the crude oil in refineries.

· For the formation of gasoline, petroleum must first be removed from crude oil.

· Gasoline itself is actually not burned, but the fumes it creates ignite.

Diesel fuel

· It is a mixture of aliphatic hydrocarbons extracted from petroleum.

· Diesel may cost less than gasoline; it costs less for production because the extraction processes used are simpler.

· It can hold dirt particles in suspension longer than gasoline because it is heavier and more viscous.

· Its efficiency varies with the type of engine.

· Use of a polluted fuel or an improper grade of fuel can cause hard starting, incomplete combustion, and a Smokey exhaust.


· Kerosene is defined as flammable hydrocarbon oil usually obtained by distillation of petroleum and used as a fuel, solvent, and thinner.

· It is sometimes used as an additive in diesel fuel to prevent gelling or waxing in cold temperatures.

· Heat of combustion of kerosene is similar to that of diesel

· It is generally used for heating and fueling vehicles.

3. Fuel gas

· Fuel gas can be referred to any of several gases burned to produce thermal energy.

Natural gas (methane) is the most common example of fuel gas, others include:

· Coal gas or Town gas

· Syngas

· Mond gas

· Propane

· Butane

· Regasified liquefied petroleum gas

· Wood gas

· Producer gas

· Water gas


Source by Prashant Chahar