Friday, September 11, 2020

Renewable Energy Sources

Integrating Wind Power into the Electricity Grid of Bangladesh” 

                               Chapter-1

1.1 Introduction

In the near future, wind energy will be the most cost effective renewable source of electrical power. In fact, a good case can be made for saying that it has already achieved this status. By 2050 except coal all other fossil fuel sources (oil & gas) will be depleted.

Wind energy has a fundamental advantage over traditional solar power, however in that its energy is more and the wind being available in a mechanical form is easily converted to useful work.

The major technology developments enabling wind power commercialization have already been made. India has been working well in wind energy. They have taken a master plan to generate 1200MW power from the wind mills.

1.2 Wind energy 

A windmill is a machine with rotating blades that is designed to convert the energy of the wind into more useful forms. Most modern windmills, more appropriately called wind turbines, are used to generate electric power. Generation of electricity by the kinetic energy of wind requires a minimum average wind speed of 21.6 km/hr, which equals 11.67 knots (1 knot = 1.85 km/hr). In Bangladesh there are some coastal areas which have similar wind power to install a wind mill. Compared to other renewable energy wind mill is most familiar in the world because in the most of the country of the world like Denmark, USA, UK, Sweden, Netherland, Argentina, Bulgeria, Kenya, are established in wind mill. India has done better in wind mill.

Wind data from Bangladesh Meteorological Department and different previous and ongoing wind resource assessment projects are briefly described in the subsequent sections.

1.2.1 Advantages:

·         This energy is the least expensive. It is available round the clock.

 

·         It doesn't cause any pollution like power plants do. Power plants depend on the combustion of fossil fuels which can pollute the air.

 

·         Windmill generators do not give off atmospheric emissions that can cause acid rain and greenhouse affect.

       ·         As wind turbines are usually built on ranches and farms, these places benefit most from them. Farm owners get rent payment from the power plant owners and at the same time, they can continue to work on their property since these turbines only use a portion of the land.

·         One of the greatest advantages of wind energy is that it is simple and renewable. The cost of producing wind energy has come down by at least eighty percent since the eighties. Along with economy, Wind Energy is also said to diminish the greenhouse effect.

·         One other advantage of wind energy that it is readily available around the clock. Wind energy may be the answer to the globe's question of energy in the face of the rising petroleum and gas prices.

·         Before the invention of steam engine wind energy was extensively used in boats, ships etc.

1.2.2 Characteristics of Wind Power:

 

1. Wind power systems are non-polluting

2. It is a renewable source of energy

3. The energy generated by wind power systems it cheaper

4. Wind energy system avoid fuel provision and transport 

1.2.3 Wind Energy Source:

All referable energy ultimately comes from the sun about 1-2% of sun’s energy that received by the earth is converted to wind energy. A wind turbine obtains its power by converting the force of the wind into torque acting on the rotor blades.

 1.3 Others Sources of Renewable Energy:

1.3.1 Biogas energy

Biogas may be the most promising renewable energy resource for Bangladesh. Presently there are tens of thousands of households and village-level biogas plants in place throughout the country. Biogas units are of three major types: floating cover, fixed cover, and plastic bag plants. Of these models, the fixed cover (dome) model has become very popular and units are disseminated throughout the country by the Institute of Fuel Research & Development (IFRD) of BCSIR. These is a real Potential to harness basic biogas technology rural electrification, via village-level biogas production and internal combustion (or even micro turbine) power generation. Such an arrangement would have the added value of providing some self-sufficiency to rural populations during periods of power shortfalls and load shedding.

 

1.3.2 Hydro energy

Micro-hydro and Mini-hydro have limited application in Bangladesh, with the exception of Chittagong and Chittagong Hill tracts. Previous hydropower assessments have identified a handful of possible sites from 10 KW to 5 MW; however, no appreciable capacity has been installed. There is one large hydro facility in the country at Kaptai, installed in the 1960s and producing 230 MW (Three unit of 50 MW and four unit of 20 MW).

 

1.3.3 Bio-diesel energy

Bio-diesel may also be one of the promising sources of energy in Bangladesh. Government of Bangladesh has taken necessary steps for Jatropha plantation, a source of Bio-diesel. A Pilot project has already been considered to verify its commercial viability. This may be a potential source of renewable energy.

1.3.4 Biomass power

Biomass is the most significant energy source in Bangladesh which accounts for 70% of the total final energy consumption in Bangladesh. The main sources of biomass fuels are

  • Trees (wood fuels, twigs, leaves, plant residues)
  • Agricultural Residues (paddy husk, bran, bagasse, jute stick etc.) and
  • Livestock (animal dung).

 Land use pattern and different biomass fuels of Bangladesh are described below in separate subsections. Approximate land use pattern of the country is

  • Agricultural land : 64 %
  • Forests : 18 %
  • Human Settlement : 8 %
  • Water and other : 10 %

1.3.5 Geothermal power

Geothermal energy is the natural heat of the Earth. It is a renewable source of energy if the exploration process doesn’t hamper the ecosystem or emit greenhouse gases. Geothermal reservoirs that are close enough to the surface to be reached by drilling can occur in places where geologic processes have allowed magma to rise up through the crust, near to the surface, or where it flows out as lava. The crust of the Earth is made up of huge plates, which are in constant but very slow motion relative to one another. Magma can reach near the surface in three main geologic areas:

  • Where Earth's large oceanic and crystal plates collide and one slides beneath another, called a subduction zone The best example of these hot regions around plate margins is the Ring of Fire and the areas bordering the Pacific Ocean: the South American Andes, Central America, Mexico, the Cascade Range of the U.S. and Canada, the Aleutian Range of Alaska, the Kamchatka Peninsula of Russia, Japan, the Philippines, Indonesia and New Zealand.
  • Spreading centers, where these plates are sliding apart (such as Iceland, the rift valleys of Africa, the mid-Atlantic Ridge and the Basin and Range Province in the U.S.A.).
  • Places called hot spots fixed points in the mantle that continually produce magma to the surface.

Because the plate is continually moving across the hot spot, strings of volcanoes are formed, such as the chain of Hawaiian Islands. There is a known hot salt water spring, known as Labanakhya, in Bangladesh at 5 kilometer to the north of Sitakunda (40 kilometer from Chittagong). Possibility of extracting energy from this site or any other unknown sites can be investigated by Satellite Remote Sensing or Physical Surveys.

1.3.6 Marine power

Bangladesh has got 710 km (441 mi) long coastal belt along the Bay of Bengal. If the marine RETs become viable option in the future, then the country may harness energy from marine RETs. The main marine RETs are

  • Tidal
  • Wave
  • Oceanic Thermal Energy Conversion
Integrating Wind Power into the Electricity Grid of Bangladesh” is a bona-fide record of work done by S.M Mizanul Haque.
ØInformation has been collected from different books, internet websites etc.

Sunday, August 24, 2014

Brushed DC Motors

Brushed DC Motors

DC Brushed motors have been used in the RC hobby from the beginning of electric flight. Until recently, the only electric motor typically found on model trains, planes, cars and boats was a DC brushed motor.
For reference, the term “brushed” simply means that there is something (brushes) touching the rotor (commutator) in order to form an electrical circuit between the battery and the armature coil windings (the copper wires you see inside). The armature is mounted to the steel axle and has multiple coil windings attached, each providing an electromagnetic force when energized by the current flowing from the brushes through the commutator.


The commutator is made of multiple contact surfaces wired to each coil so that the brushes are “handing off” energy to the next coil in order to maintain rotation of the rotor. Each rotation hands the coils off to the opposite brush which means each armature coil is energized creating magnetic attraction, pulling itself towards the next permanent magnet. The motor housing has fixed, permanent magnets of opposite poles mounted around the spinning armature. This sets the stage for a consistent magnetic environment for which the armature coils can either push or pull, creating rotation.

Airplane Use

Pros and Cons:

Inexpensive Performance degrades over time
Easy to wireHigher resistance than brushless
Electronic Speed Controls (ESCs) are cheaperLess powerful than brushless
Can be “ganged” together in parallel and powered by the same ESCHeavier than brushless counterpart

Common Types

Canned/Can Motors

The picture above is of a typical “canned” motor. Canned motors are usually included in a kit, are very inexpensive, use lower strength ferrite permanent magnets, plastic or porous brass bearings and are non-serviceable. They will fly the model they were supplied with just fine but if you want to get higher performance out of your airplane, you can upgrade to a brushed motor with higher quality components and, specifically, better magnets and brushes or even move into a brushless configuration.

Rare Earth Motors

Rare earth motors commonly use Cobalt or Neodymium magnets to achieve much higher performance than their ferrite counterparts. Another added advantage is that Cobalt and Neodymium experience less performance degradation than Ferrite as temperatures increase.
Rare earth brushed motors are made of better materials all around, such as:
  • Better cases with improved heat dissipation
  • Roller bearings for reduced friction
  • Replaceable brushes for longer overall serviceable life
  • Higher quality components with better conductivity and less wear

General Considerations

An unfortunate characteristic of magnets is that they lose strength the hotter they get. Higher quality magnets perform better in higher temperatures but also cost significantly more.
You can install a heat sink over the motor housing (avoid covering air holes) to help dissipate heat and maintain performance. Check for proper clearance before mounting; heat sinks require more room than the stock motor alone. The following image is a typical slip-on heat sink for an electric motor.


Another unfortunate characteristic related to brushed motors is that the brushes and commutator break contact during rotation. This results in a loss of energy transferred to each stator coil. This also causes all of the stored electrical energy to “arc”, resulting in Radio Frequency Interference (RFI). This electrical “noise” can wreak havoc on your radio receiver and even your servos. 2.4 GHz radios operate outside of the susceptible frequency range but you can still get interference to your other components.
The effective use of a capacitor on each motor lead can isolate or “buffer” this condition and reduce or eliminate any interference the motor is generating. Some motors already have capacitors installed internally but you should always investigate before launching your model and losing control! There is more information regarding interference in the Radio Systems section and the break-in section below.

Wiring

**Always use caution and keep your hands and all other objects out of the path of a moving prop. These seem like toys but smaller models can remove finger tips and larger models can actually amputate fingers and even cause death**
One of the benefits of a brushed DC motor is that it uses only two wires to operate. As conventional as it seems, you have a positive and negative lead from the Electronic Speed Control (ESC) that provided variable current to the motor for proportional (gradual) control from idle to full speed. Connections are polarity sensitive and in order to get the correct rotational direction you may have to reverse the leads from the ESC going to the motor NOT FROM THE BATTERY TO THE ESC!!!.

Connect the esc to the motor without the prop installed (safest) and gently increase the throttle to see which way it is turning. If it is turning in the wrong direction, power off, reverse the two wires, and reconnect. The illustration above shows a brushed DC motor properly connected to an ESC, connected to a battery and radio receiver.


See the Tools section for our
Motor Sizing Calculator.

DC Brushed Motor Break-In

As the old saying goes with gas engines: “Break it in, or [you'll] break it down!” While it’s nothing quite that extreme with electric motors, a properly broken-in brushed DC motor will give many hours of cooler, more efficient and more powerful operation. Breaking-in a motor refers to “seating” the brushes properly on the commutator. The goal is to gently wear the brushes against the commutator in order to achieve a smooth fit, maximizing the contact surface area. This makes for a more efficient transfer of energy and reduces arcing which results in less heat created on the commutator surface as well as less Radio Frequency Interference (RFI). A broken-in motor can produce 10-30% more power than one pulled out of the box and put into full service.
** Note ** All procedures mentioned are assuming a bare motor, with no prop attached or gearbox. Break-in procedures are most effective under no load! Also, break-in the motor in the intended operational direction for most effectiveness.

Methods and Variables

Let the debate begin! Each hobbyist has a different method they swear by for breaking in a DC brushed motor. Manufacturers even have their own procedures. I would recommend for starters investigating the manufacturer’s recommended break-in procedures for your specific motor as any other method may void the warranty. But, if there are no specific recommendations and you are comfortable going out on your own, let’s begin with the major factors to consider:
Low Temperature - Heat is not required to break in a motor! In fact, room temperature is just right. Some people even ice their motors during break-in.
Minimal Arcing - Arcing causes pits to form both on the brush surface as well as the commutator. Arcing also generates unwanted heat. Break-in recommendations are to supply 1/3 to 1/2 the normal operating voltage. This greatly reduces arcing.
Cleanliness - As the brushes wear against the commutator, small carbon particles begin to collect and blow around inside the motor. While this is relatively minimal, the particles do stick everywhere and also grind between the brushes and commutator. Some people say this is beneficial to getting a good seat and I’m not here to debate the point, but my personal preference is to keep the motor clean during break-in.
Voltage - Break-in recommendations typically average the supply voltage to around 1/3 to 1/2 operating voltage. Again, the goal is to minimize heat and arcing and allow the brushes to gracefully seat themselves into the commutator. So, on a 12 volt motor you’d break it in on 4-6 volts. It’s perfectly ok to start at 2 or 3 volts and ramp up to a higher voltage over time. Something you will see during the break-in is the amperage will decrease going to the motor. If you’re savvy with a multi-meter, or have an amp meter, watch the amperage decline while the motor is running as the brushes become more efficient!
Time - Most break-in procedures range from 60-120 minutes. Some battery chargers even have a motor break-in feature that allow you to set the step voltage and time for your motor break-in to your liking. It will automatically increase the voltage over the course of the break-in for a gentle ramp through the RPM range. If you monitor the amperage draw, you will see it “level off” at some point. Once this is achieved, the break-in is finished and you’re ready to run your motor at standard operating speeds. If you are using the battery method and cannot monitor the amperage draw, I would recommend at least an hour break-in to obtain effective results.

DuraTrax IntelliPeak ICE charger breaking-in a Brushed DC motor

** Note ** Do not directly connect Lithium Polymer or Nickel-Metal Hydride rechargeable batteries for motor break-in unless you plan to disconnect them before they reach minimum voltage. Lithium Polymer (Li-Po/Li-poly) and Nickel-Metal Hydride (NiMH) batteries should not be discharged below certain levels or they become permanently damaged or suffer reduced life and performance. See the Batteries section for more information about proper usage of your rechargeable batteries. If you plan to use a direct-connected rechargeable source, I keep an old 4 cell (4.8 volts) Nickel-Cadmium (Ni-Cd) battery around; they have no problem with being fully discharged.

Wet -vs- Dry

Wet
Wet break-ins involve submerging the motor (not the battery or anything else) in liquid in order to keep it cool and wash away carbon debris. A common myth is that the water will cause a short in the motor and even overheat the battery. Simply not true.
Some people use Distilled Water, Rubbing Alcohol or common tap water. I would caution the use of tap water due to the fact that minerals in the water leave deposits all over the inside of your motor. Those same minerals also greatly increase the conductivity of the water, not that this is really a problem during break-in, but I’m not keen on leaving abrasive, conductive minerals all over inside my electric motor.
Rubbing Alcohol does pose some fire risk, albeit minimal, but evaporates nicely after the break-in is finished. Consider performing the break-in outdoors and away from structures if you are using rubbing alcohol. Water break-ins must be cleaned afterwards to avoid corrosion and rust. I use compressed air through the holes and this works pretty well. You also will want to lubricate the bushings at the end of the axle with some very light weight hobby oil or even a couple drops of 3-in-1 or sewing machine oil. GO SPARINGLY. An oily motor collects dirt and can greatly interfere with your commutator/brush efficiency. Avoid getting it all over inside the motor and avoid penetrating lubricants such as WD-40. Just a drop on the bushings from the outside will do. Don’t disassemble the motor after break-in! The brushes typically do not seat the same after re-assembly.
Dry
Dry break-ins are most common and are very easy. In fact, many people do their break-ins with alkaline batteries as the power source and a heat sink snapped over the motor to help keep it cool. They simply let it run until the batteries are dead. Again, we have almost nothing to lose here! Even a partially broken-in motor will out-perform a new one. With dry break-ins, keep the motor in a well ventilated area, away from heat sources, and you’ll have excellent success. Use the Voltage recommendations below to properly size your source batteries.

Sunday, August 10, 2014

Researchers Develop New Amp to Study Universe


Researchers at NASA’s Jet Propulsion Laboratory (JPL) and the California Institute of Technology (Caltech), both in Pasadena, have developed a new type of amplifier for boosting electrical signals. The device can be used for everything from studying stars, galaxies and black holes to exploring the quantum world and developing quantum computers.
“This amplifier will redefine what it is possible to measure,” said Jonas Zmuidzinas, chief technologist at JPL, who is Caltech’s Merle Kingsley Professor of Physics and a member of the research team.
An amplifier is a device that increases the strength of a weak signal. “Amplifiers play a basic role in a wide range of scientific measurements and in electronics in general,” said Peter Day, a principal scientist at JPL and a visiting associate in physics at Caltech. “For many tasks, current amplifiers are good enough. But for the most demanding applications, the shortcomings of the available technologies limit us.”
The new amplifier (above) consists of a superconducting material, niobium titanium nitride, coiled into a double spiral 16 millimeters in diameter.
Although the amplifier has a host of potential applications, the reason the researchers built the device was to help them study the universe. The team built the instrument to boost microwave signals, but the new design can be used to build amplifiers that help astronomers observe in a wide range of wavelengths, from radio waves to X-rays.

Green Technology

Green Technology

Greenhouse emissions and Global warming are not just news stories; they are concerns that are driving change. Electrical "Green" technologies are gathering momentum for new development; retrofit solar- electric augmentation, energy smart homes and commercial buildings. Are you ready?
We at E & S Electric are staying above the curve of the latest technologies in our industry. We can assist in the designing, application, installation, analysis, LEED certification, and work with your local utilities reimbursements process.
"Green" Technology often translates into huge savings especially on electricity costs, enough to pay for the project over the long-run. Also it could mean tax breaks. Remember save the Earth and save money too. We've been researching and implementing "green" for years. Our ongoing research and training will give our clients the best for this evolving change "green" has to offer.
Here is a list of the "Green" Retrofit jobs we have completed.
  • St Vincent DePaul locations in Madison, Waunakee and Stoughton
  • Mt. Horeb School District
  • Sun Prairie School District
  • Belleville School District
  • Suttle Straus, Waunakee
  • VFW Post 7591, Madison
  • Monroe Lumber
  • Piggly Wiggly Sauk City
  • St. John Catholic School Waunakee
  • CL Swanson, Madison
  • Federal Industries, Belleville
  • Mt. Horeb Youth Center
  • Robert W. Baird, Madison
  • Movie Gallery, Mt. Horeb
Here is a list of completed jobs with energy saving lighting controls:
  • Iconica, Madison
  • Madison National Life Insurance, Madison
  • Wells Fargo, Madison
  • Tomotherapy, Madison
  • Associated Bank, Madison
  • State Bank of Cross Plains, Mt. Horeb
  • Amcore Bank, Madison
  • Farmers Saving Bank, Mt. Horeb
  • First National Bank of Platteville
  • UW Credit Union locations in Madison, Monona, Glendale, Sun Prairie, Middleton
  • Holliday Inn, Madison
  • USDA, Madison
  • The Gialamas Company, Madison
  • Kalahari, Lake Delton
  • Minitube, Mt. Horeb
  • Mirus, Madison
  • Hill & Wilson Dental Clinic, Madison
  • Madison Vein and Laser, Madison

What is LEED?

LEED stands for - Leadership in Energy and Environmental Design.
LEED provides third-party certification for buildings to meet the highest standards for energy efficiency and environmental responsibility. LEED provides building owners and operators with the tools they need to have an immediate and measurable impact on their buildings. The LEED program is helping the industry; adopt where we design, locate, build and retrofit buildings to achieve sustainability in our work and life styles" E & S Electric goal is to be doing green (vs. going green)with help from loyal customer and our community to generate sustainable revenue, achieving sustainability now and for the future for Mother Earth. LEED Accredited professionals are professionals who understand the green building practices, principles and a familiarity with LEED requirements, they can help you understand the LEED process and be the resource for you to move to the sustainability movement by following guidelines of the USGBC.
THE U.S.GREEN BUILDING COUCIL (USGBC) is a nonprofit composed of leaders from every sector of the building industry working to promote building communities that are environmentally responsible, profitable, and healthy place to live and work.