Sunday, January 1, 2012

Advantages and Disadvantages of Wind Energy

!±8± Advantages and Disadvantages of Wind Energy

Wind energy is the fastest growing renewable energy source in the world. The technology is now seen as having so many advantages that in Europe and the United States, wind-powered generating capacity increased by 18 percent and 27 percent, respectively, in 2005 alone.

Foremost of those advantages; it is a clean source of electricity produced when specially designed wind turbines capture the wind to generate electricity. In the same way as historical windmills, modern wind turbines generate power from the wind. The latest technology produces wind energy reliably and efficiently. Unlike other power plants, wind energy systems require minimal maintenance and have low operating expenses.

Wind energy is, in fact, a method by which solar energy is converted into electrical power. The sun's radiation heats different parts of the earth at different rates - most notably during the day and night, but also when different surfaces (for example, water and land,) absorb or reflect at different rates. That creates the winds that wind turbines use to create electricity, and the electricity they produce is generated right up on the mast behind the turbine blades. A simple cable then conducts the power into the electrical power grid

Wind is a clean fuel; wind farms produce no air or water pollution because no fuel is burned. This means that wind energy is also a source of clean, green non-polluting, electricity. Unlike conventional power plants which burn carbonaceous fuels, wind plants emit no air pollutants or greenhouse gases.

Wind energy is one of the cheapest of the renewable energy technologies. It is competitive with new clean coal fired power stations and cheaper than new nuclear power. Small wonder then that wind energy is the leading renewable energy technology.

It can be developed much further and given the right support it could provide up to 28% of EU electricity by 2030. Wind energy is popular as well. Dozens of surveys have been conducted in the U.S. that have shown its popularity. One reason why it is popular, especially in remote windy areas, is partly due to the fact that wind energy creates 27 percent more jobs than advanced coal technology and twenty times more jobs than natural gas combined cycle.

Wind energy is plentiful in most parts of the world, renewable, widely distributed, clean, and reduces greenhouse gas emissions by displacing fossil-fuel-derived electricity. Therefore, it is considered by experts to be more environmentally friendly than most other energy sources. Wind energy is also a permanently available form of energy. The wind will exist for as long as the sun exists, which is roughly another four billion years!

Wind energy is clean energy. Unlike coal or natural gas, every kilowatt-hour of wind energy is free of the toxic emissions that pollute our air and water.

Wind energy is one of the fastest-growing forms of electricity generation in the world. The United States can currently generate more than 10,000 megawatts (MW) of electricity from the wind, which is enough to power 2.5 million average American homes. Wind energy is a pollution-free, infinitely sustainable form of energy. It doesnâEUR(TM)t use fuel; it doesnâEUR(TM)t produce greenhouse gases once built, and it doesnâEUR(TM)t produce toxic or radioactive waste.

Wind energy tends to be available in winter when power is needed and is available overnight, when solar energy is unable to provide direct power.

However, wind energy is not immune from disadvantages.

This form of energy is intermittent at any one site, and can only be generated when wind velocities are within a certain range. During high winds which would possibly damage the turbine blades the turbine is stopped and automatically furled, and when wind velocities are too low they can obviously not provide power either.

This means that there will always need to be backup fossil fuel power stations which the generating company will need to hold in readiness for windless days, and providing these plants will be very expensive.

Some say that if the power grid extends across several nations there will always be somewhere that is windy enough to be generating power at any time. However, they tend to forget that there are energy losses in the power distribution lines which eventually, across large distances, render such large distribution distances uneconomic.

Therefore, as the proportion of wind energy supplying national grid systems increases, power engineers will face an ever increasing challenge to balance the power across the system and provide all their users with a dependable continuous supply on airless and calm days. It is not clear how that can be achieved once the proportion of wind energy rises above a certain threshold.

There are many other disadvantages of wind power, which are less important, but nevertheless of great concern to those which will need to accommodate wind turbines as their close neighbors.

Modern windmills are not devoid of environmental impacts upon their localities and the most important of these can be listed as:-

- turbine blade noise
- potential for disturbance to wildlife and a hazard to flying birds which may be hit by the blades
- visual intrusion, especially since the highest winds are usually found in some of the most remote, beautiful and most unspoilt places around the world.

Nevertheless, in more than 50 countries the locals are clearly being willing to reduce as far as possible these impacts by careful site selection and turbine design. Then they are coming to terms with those disadvantages which remain, to help their nations maintain power supplies against rising oil price rises, and do this in a renewable way, at low cost, and with very low greenhouse gas emissions.

For this reason we say that all of us must expect to see more and more wind farms being built right across the countryside and out at sea as well.


Advantages and Disadvantages of Wind Energy

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Friday, December 30, 2011

HVLP Spray Guns - Atomization Technologies - Part 2

!±8± HVLP Spray Guns - Atomization Technologies - Part 2

In essence, an HVLP gun is still an air spray gun as it uses air as its primary atomization force. Both HVLP and conventional air spray guns use the same two components of compressed air, pressure and volume but in different quantities. The pressure, which is normally noted in terms of pounds per square inch or PSI and volume, which is noted in terms of cubic feet per minute, are both necessary for either gun to work.

Originally HVLP guns where designed to use extremely high volumes of CFM that were generated by turbines rather than compressors. These turbines delivered, in some cases, hundreds of CFM but very little pressure. In order to remain competitive with the turbine HVLP guns, the manufacturers of the traditional air spray guns soon figured out how to convert their guns to HVLP using compressed air rather than turbine air. Today HVLP guns are as common as the old conventional guns.

HVLP technology proved that if you used a lot of volume of air instead of a lot of pressure like conventional guns did, you could not only atomize coatings but also do so more efficiently. The efficiency improvement was mostly related to the fact that the atomized paint particles traveled at a slower speed than paint particles that were atomized with high air pressure. We refer to this characteristic as spray particle velocity. The higher the velocity of the paint particle the lower the efficiency would be.

I like to use the analogy of a tennis ball and a cement wall. The paint particle is representative of the atomized paint particle and the wall represents the substrate being coated. The harder you throw the ball against the wall, the further the ball bounces from the wall. During air spray atomization the paint particle can travel at speeds greater than 30 feet per second or FPS. When the same coating is atomized with HVLP technology, the FPS drops to 10 to 23 FPS. The slower the particle velocity, the less bounce back and over spray, the more efficient the technology will be.

In addition to spray particle velocity, another characteristic that affects guns that use a lot of volume of air such as HVLP is air damming. Here I like to use the analogy of a 2' high by 2' wide by 2' deep box and blocks that are 1' high by 1' wide by 1' deep. In this scenario the box is the inside of a cabinet and the blocks represent a cubic foot of air from your gun. Try to imagine these blocks of air as they exit the spray gun and enter the box. When you spray into the box you are filling it with the blocks of air. The inside area of the box can only hold 8 cubic feet or 8 blocks, but the gun you are using is putting out 20 cubic feet per minute or 20t blocks per minute.

The result is that within seconds you are putting too many blocks into the box and those extra blocks are preventing you from putting in more blocks and they are spilling out all over the place. The volume of air has to go somewhere because it usually can't pass through the item you are trying to spray. The high volume of air from the gun is preventing more air and most importantly, the coating from getting into the box. This is an example of air damming and the higher the volume of air the more damming you will get.

In addition to air damming there is the problem of air turbulence. Turbulence results from sudden changes in wind direction and velocity. This causes the aircraft to bounce and move rapidly in directions that are not intended. Anyone that has ever flown in an airplane or jet has probably experienced it first hand. As the atomizing air exits the spray gun it begins to interact with the coating and the surrounding air in the atmosphere creating turbulence. Additionally, the air and coating interact with the substrates' geometry creating eddies and currents which add to the turbulence. All guns create their own turbulence during atomization but guns with high atomizing pressures or high volumes of air will create more turbulence than guns that use low pressures and very low volumes of air.

So aside from these characteristics that are shared by conventional air spray, HVLP, LVLP and RP guns, one should also understand the benefits and limitations of HVLP. For the most part the benefit is reduced coating usage as HVLP has been proven to increase ones' transfer efficiency. In essence transfer efficiency is than percent of paint solids that leave the spray gun during atomization that actually end up on the substrate and not in the spray booth filters, booth walls or the booths floor. Some manufacturers have seen coating savings per square foot of up to 50% while others may only see savings of 15 to 20%. Much depends on your coating, your environment, your finishers and how well your conventional gun was set up in the first place.

As for the limitations, HVLP guns use substantially more CFM than conventional guns. This means that you will most likely be paying more for electricity to run your compressor at best or you might need to upgrade to a larger compressor at worst. Although the overall atomization of HVLP has greatly improved, atomization quality can be negatively affected by high viscosity and or high flow rates. Most states require that HVLP guns be limited to 10 psi at the air cap because pressures higher than that begin to decrease the guns' efficiency substantially. So if your material is viscous or if you are running high flow rates you may be hampered by this 10-psi limit or by the declining efficiency should you exceed 10 psi.

Low Volume Low Pressure

To help users with limited compressed air availability, some gun manufacturers have introduced Low Volume Low Pressure guns. These guns are designed to reduce spray particle velocity like HVLP guns, but can actually use less air than a conventional gun. This can help reduce the high electricity costs associated with the high cfm demand of HVLP guns. However, it is recommended that you evaluate these guns thoroughly for finish quality and efficiency before automatically switching to this technology. The money you save in electricity may be outweighed by a loss in efficiency or finish quality. Then again, you may find that some of they are actually more efficient or give you a better finish and save you money on your electric bill. The only way to be sure is to try them at your facility, with your coatings and your finishers.

Another advantage of this technology is their ability to deliver pressures substantially higher than HVLP. For companies or industries that are not restricted by state environmental regulations concerning the 10-psi limit, these guns can handle higher viscosities and flow rates than HVLP guns but most likely at lower efficiencies. However, the efficiencies are usually significantly higher than Conventional Air Spray. LVLP guns are considered HVLP compliant but only if operated at 10 psi or less at the air cap.

All of the above low fluid pressure, air spray technologies are available in siphon, gravity and pressure feed formats. However, keep in mind the limited siphoning ability of some of these guns, especially if your material is viscous or if you need to spray at high flow rates. It is also important that you make sure that the gun you select can be operated within the compliant pressure range (10 psi for HVLP) or that it is recognized as a compliant technology, if you are required to do so by any state environmental regulations.


HVLP Spray Guns - Atomization Technologies - Part 2

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Tuesday, December 27, 2011

Fuji 9600-4 Fuji Xpc HVLP Turbine Spray Gun

!±8±Fuji 9600-4 Fuji Xpc HVLP Turbine Spray Gun

Brand : Fuji
Rate :
Price : $299.00
Post Date : Dec 27, 2011 13:48:51
Usually ships in 24 hours



The Fuji XPC spray gun features a side pattern control knob to adjust the size of the fan from small round to large and any size in between. The pattern control knob allows you to adjust to the exact size of the object you are spraying. This is a tremendous improvement over the antiquated collar pattern adjustment still used on most HVLP turbine guns that do not provide fully incremental sizes. Other desirable features include 100% stainless fluid components, stainless springs, metal knobs and collar, ergonomic handle that is always cool to the touch. 1000cc (1 qt) bottom feed cup is installed â?" this is the ideal size for medium to large sized projects such as cabinets, furniture etc. 1.4 mm air cap set #4 is installed â?" perfect size for most fine-finishing.

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