Thursday, 28 November 2013
Modern Radiators have their filler necks covered with a Pressure Cap. It maintains an air tight joint which helps to keep the coolant at a pressure higher than atmospheric pressure.
This helps in the following ways:
1. The engine can operate at higher temperature without boiling the coolant. This ensures higher rate of heat transfer. (Rate of heat transfer depends on the difference in temperature between the Coolant and Atmosphere. Higher difference in temperature ensures higher rate of heat transfer.)
2. At higher altitude, atmospheric pressure is low. This causes the coolant to boil at comparatively low temperature. With the Pressure Cap, a higher pressure is maintained inside, irrespective of any change in atmospheric pressure. Thus maintaining cooling system efficiency.
The Pressure Cap contains a Pressure Valve and a Vacuum Valve. If, due to severe working condition, the coolant starts boiling or vaporise, the pressure in the system exceeds a certain value, the Pressure Valve opens and releases the excess pressure to the atmosphere through an over flow pipe.
On the other hand if sudden cooling happens, a vacuum is created inside the Radiator, then the vacuum valve opens to avoid collapse of the Radiator.
It is important to remember that the Pressure Cap should never be opened when the Radiator is still hot. Because, on removing the cap, the pressure inside the Radiator will suddenly drop, causing the boiling point of the coolant to decrease all of a sudden. This causes the coolant to start boiling immediately. This may cause spill over and burn anyone standing nearby. In case of loss of a Pressure Cap, the replacement cap should be of the same pressure rating as the original one.
In most of the modern engines, instead of overflow pipe an Expansion Tank is provided. This tank is so connected with the Radiator that it receives the excess coolant when the engine is heated. When temperature decreases, the coolant volume reduces and the coolant in the Expansion Tank returns to the Radiator. This ensures that the Radiator is always full of coolant. The reservoir is usually made of semi transparent plastic so that it can indicate the level of coolant.
Such a system is also called as Coolant Recovery System, it has the following advantages:
1. There is no loss of coolant due to overflow.
2. Air does not enter into the system. Corrosion of the cooling jackets is reduced considerably.
Wednesday, 27 November 2013
Electricity is an integral utility in modern society, with links to everything from a human's subconscious fear of the dark to the practical need for working illumination in an industrialized world. The entire world essentially runs on electricity, in one form or another, and while combustibles are essential at the present time as well, their time is nearing an end. Electricity is not only ingrained in modern life, it is also critical for its continued existence, as electricity will soon be the main source of power produced world-wide.
All of the modern energy alternatives are focused on creating electricity by renewable means, such as wind turbines, solar arrays and geothermic heating, ultimately using steam to turn large turbines, creating electricity. Electricity is the future but it is also the past and present, as without a continuous power supply, many living with assistance would not be able to cope. Most of the modern medical treatments that are commonplace today would be extremely risky if not impossible, without modern power and lighting.
Lighting alone is the backbone of civilization. Without proper lighting, travel would be a life-threatening process at every step, risking collisions, getting lost frequently and impacts with stationary objects, even with the modern, high-power headlights on vehicles today. Electric power runs the world, with governments, corporations and financial institutions relying on it daily for communication, commerce and even direct trading. The grip of electric power also extends to the smallest and seemingly insignificant aspects of the average citizen, from mobile communications to the ability to cook indoors. Electric power is and will continue to be, one of the most important energy forms available to the human race as a whole and as fossil fuels steadily run out, more and more dependence upon it will become the standard.
People depend on electricity for everything. From television to refrigerators and kitchen appliances to mobile phones; it powers virtually everything in our life. Everything requires electricity to function. Banks and ATMs require electricity to maintain their databases without which no transactions could be made. Gas pumps and gas companies need a lot of electricity to operate without which people cannot travel. Fridges in grocery stores and in people’s apartments need constant electricity as canned and unsealed foods like meats, chicken, poultry etc can get spoilt. Traffic lights and safety systems find electricity indispensable.
In today’s era, energy demands are exponentially high and energy resources are depleting rapidly. It’s now time to come up with some innovative and brilliant ideas to generate environment friendly and low cost energy without utilizing the already becoming extinct energy resources. The following list is a compilation of some excellent ways to generate power.
· Cycling to generate electricity - The Crown Plaza Hotel in Copenhagen, Denmark, was the first one who came forward with an exciting and innovative way to generate power. They offer a free meal to any guest who produces electricity for the hotel on an exercise bike attached to a generator. The guests have to produce at least 10 watt hours of electricity which is around 15 minutes of cycling to get a meal vouchers worth $36 (26 euros). This system gives health benefits as a byproduct to the generated electricity. The energy produced can generate energy to run a laptop for approximately 30 minutes. The idea is easy to implement and can be implemented by anyone on an individual’s level.
· Car washing - The innovative device designed by Vandenbussche, POWA Water Generator, is a small turbine that is placed in between the hosepipe used to wash to cars or water the lawn. As the water rushes through the pipe, the blades of the small turbine turn and generate electricity. This company envisioned the system to charge the batteries of the electric cars but this electricity can be used for other purposes also.
· Dancing on Floor of a Club - Till date it has been known that clubs are the maximum consumers of electricity as the music and the lighting systems consume a lot of power on daily basis. Now the clubs are an excellent place to generate power too. The idea was implemented by a club, Bar Surya, in London, that re-outfitted its floor with springs. The springs when compressed by dancers, produce electrical current. This current is stored in batteries and consumed to run the devices in the club. The dance floor can now power 60 percent of the club’s energy needs.
· Exhaust of a Vehicle - The unconsumed fuel of the vehicle comes out from the exhaust in the form of heat. This heat can be harnessed to generate electricity. Thermoelectric generators convert heat into electrical energy by making use of a temperature gradient. The greater the temperature difference, the more current can be produced. Researchers say that the temperature difference between the exhaust pipe and a pipe carrying engine cooling fluid can thus be several hundred degrees Celsius. This temperature difference is used to generate current. This electricity can cover a fairly good proportion of car’s power requirements.
· Solar Panels on Rooftops - An interesting way to generate electricity is by covering the roof of the house with a layer of solar panels. These panels serve dual purpose as they in addition to generating electricity provide insulation and lower the temperature of the house. The panels can also be placed in the backyard.
New and further developments have taken place in the domain of energy and power generation by various industries. The use of cutting-edge technology for fossil fuel generation has been made possible by one such technology known as the CO2 Capture and Storage technology which aims at impacting the environment in minimal ways.
CCS (Carbon Capture and Storage) technology is a totally innovative process. Firstly, CO2 is separated from other gases produced in coal-fuelled plants, and then it is captured and transported to storage sites. Thus, the carbon dioxide produced in plants is seized and trapped in geological formations, such as depleted gas and oil reservoirs and deep saline aquifers.
Tuesday, 12 November 2013
A light-emitting diode (LED) is a semiconductor of light source. LEDs are used as indicator lamps in many devices and are increasingly used for general lighting. Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor.
The lifespan of an LED surpasses the short life of an incandescent bulb by thousands of hours. Studies reveal that LED bulbs produce less carbon than older bulbs, which can be very useful to get rid of the ill effects of global warming.
These energy saving bulbs have a very long life, and they are able to remain consistent despite of long-term use. In other words, they are not easily hampered, even if you are using them for long hours. So, one can buy the bulbs according to their preference, those which do not need to be swapped frequently.
Light-emitting diodes are used in applications as diverse as aviation lighting, automotive lighting, advertising, general lighting, and traffic signals. LEDs have allowed new text, video displays, and sensors to be developed, while their high switching rates are also useful in advanced communications technology. LED grow lights have been one of the best innovations in farming as it helps improve the different aspects of gardening. There are interesting applications also which uses LED bulbs such as UV-LEDs for the sterilization of water and disinfection of devices and to enhance the photosynthesis in plants as a grow light.
Wednesday, 6 November 2013
ENVIRONMENTAL IMPACT OF ELECTRICITY GENERATION
All energy conversion methods used to produce electricity have some environmental impact. The impact may have an active effect like the emission of airborne pollutants, or may have a passive effect like aesthetics or habitat modification. Even methods considered environmentally friendly, like wind, solar, and hydro, have some impact on the environment. Not only does the final production of electricity have an environmental impact but the transmission of electricity with concerns over electromagnetic fields, aesthetics, and land use, also impacts the environment.
The whole cycle of electricity generation must be considered when looking at the environmental impact. This includes the production and transportation of fuel for the conversion process. This is especially true of fossil fuel and nuclear power plants, which use large quantities of fuel taken from the earth. Energy system environmental impact consists of fuel recovery and production, fuel transportation, electricity transmission, and spent fuel emissions.
Fossil fuel power plants generally have the most widespread effect on the environment, as the combustion process produces airborne pollutants that spread over a wide area. Nuclear power plants have the most potentially dangerous effect. An operating accident at a nuclear station could allow a large release of radioactive particles to occur. Solar, hydro, and wind power plants generally have smaller effects on the environment.
Nonetheless, these renewable sources of energy provide substantial benefits for our climate, our health and our economy. Each source of renewable energy has unique benefits and costs like little to no global warming emissions, improved public health and environmental quality and a vast and inexhaustible energy supply etc.
ENVIRONMENTAL IMPACTS OF HYDROELECTRIC POWER
Hydroelectric power includes both massive hydroelectric dams and small run-of-the-river plants. Large-scale hydroelectric dams continue to be built in many parts of the world leaving a lasting impact on the world. The amount of water usage is often of great concern for electricity generating systems as populations increase and droughts become a concern.
Still, hydroelectric power is the most energy efficient power generator. Currently, hydropower is capable of converting 90% of the available energy into electricity. This can be compared to the most efficient fossil fuel plants, which are only 60% efficient.
LAND USEThe size of the reservoir created by a hydroelectric project can vary widely, depending largely on the size of the hydroelectric generators and the topography of the land. Hydroelectric plants in flat areas tend to require much more land than those in hilly areas or canyons where deeper reservoirs can hold more volume of water in a smaller space. Flooding land for a hydroelectric reservoir has an extreme environmental impact: it destroys forest, wildlife habitat, agricultural land, and scenic lands. In many instances, such as the Three Gorges Dam in China, entire communities have also had to be relocated to make way for reservoirs.
Dammed reservoirs are used for multiple purposes, such as agricultural irrigation, flood control, and recreation, however hydroelectric facilities can still have a major impact on aquatic ecosystems. For example, though there are a variety of methods to minimize the impact (including fish ladders and in-take screens), fish and other organisms can be injured and killed by turbine blades.
Yet, before a project can be developed, it must go through a rigorous process of screening that examines the impact the project would have on the environment and the local communities. Water flow, water quality, water shed management, fish passage, habitat protection as well as the welfare and lifestyle of the local communities are taken into consideration.
Although hydroelectric power can prove to be a challenge to the environment, it yet has a distinct advantage over fossil fueled generator plants: it is clean, green and renewable and has very low operating costs. It is renewable because it draws its essential energy from the sun that drives the hydrological cycle, which in turn provides a continuous renewable supply of water. Hydropower does not contribute to local air pollution.