Science Bar

Wednesday 6 January 2016

Hydroelectric Power Station


Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation – 3,427 terawatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years.

Hydropower is produced in 150 countries, with the Asia pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use.
The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour. It is also a flexible source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing energy demands. However, damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and wildlife. Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the (CO2) than fossil fuel powered energy plants.
TUTORIAL LINK: Can be made as a model. LEDs can be added along with batteries to show electricity production.



Tuesday 5 January 2016

Electric Car


An electric car is an automibi that is propelled by one or more electric motors, using electrical energy stored in rechargeable batteries or another energy storage device. Electric motors give electric cars instant torque, creating strong and smooth acceleration. They are also around three times as efficient as cars with an Internal combustion engine.

The first electric cars were produced in the 1880s. Electric cars were popular in the late 19th century and early 20th century, until advances in internal combustion engine and mass production of cheaper gasoline vehicles led to a decline in the use of electric drive vehicles.

Sunday 3 January 2016

Rain Sensor


rain sensor or rain switch is a switching device activated by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall. The second is a device used to protect the interior of an automobile from rain and to support the automatic mode of windscreen vipers. An additional application in professional satellite communications antennas is to trigger a rain blower on the aperture of the antenna feed, to remove water droplets from the mylar cover that keeps pressurized and dry air inside the wave-guides.

Rain sensors for irrigation systems are available in both wireless and hard-wired versions, most employing hygroscopic disks that swell in the presence of rain and shrink back down again as they dry out — an electrical switch is in turn depressed or released by the hygroscopic disk stack, and the rate of drying is typically adjusted by controlling the ventilation reaching the stack. However, some electrical type sensors are also marketed that use tipping bucket or conductance type probes to measure rainfall. Wireless and wired versions both use similar mechanisms to temporarily suspend watering by the irrigation controller — specifically they are connected to the irrigation controller's sensor terminals, or are installed in series with the solenoid valve common circuit such that they prevent the opening of any valves when rain has been sensed.

Some irrigation rain sensors also contain a freeze sensor to keep the system from operating in freezing temperatures, particularly where irrigation systems are still used over the winter.

Saturday 2 January 2016

Current Sensor


current sensor is a device that detects electric current (AC or DC) in a wire, and generates a signal proportional to it. The generated signal could be analog voltage or current or even digital output. It can be then utilized to display the measured current in an ammeter or can be stored for further analysis in a data acquisition system or can be utilized for control purpose.

TUTORIAL LINK: https://m.youtube.com/watch?v=pN_IKGnDwIg

Friday 1 January 2016

Carbon Catcher And Storage


Carbon capture and storage (CCS) (or carbon capture and sequestration) is the process of capturing waste carbondioxide (CO2) from large point sources, such as fossil fuel power plant, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation. The aim is to prevent the release of large quantities of CO2 into the atmosphere (from fossil fuel use in power generation and other industries). It is a potential means of mitigating the contribution of fossil fuel emission to global warming and ocean acidification. Although CO2 has been injected into geological formations for several decades for various purposes, including enchanced oil recovery, the long term storage of CO2 is a relatively new concept. 

An integrated pilot-scale CCS power plant was to begin operating in September 2008 in the eastern German power plant Shwarze Pumpe run by utility Vattenfall, to test the technological feasibility and economic efficiency. CCS applied to a modern conventional power plant could reduce CO2 emissions to the atmosphere by approximately 80–90% compared to a plant without CCS. The IPCC estimates that the economic potential of CCS could be between 10% and 55% of the total carbon mitigation effort until year 2100.

Capturing and compressing CO2 may increase the fuel needs of a coal-fired CCS plant by 25–40%. These and other system costs are estimated to increase the cost of the energy produced by 21–91% for purpose built plants. Applying the technology to existing plants would be more expensive especially if they are far from a sequestration site. Recent industry reports suggest that with successful research, development and deployment (RD&D), sequestered coal-based electricity generation in 2025 may cost less than unsequestered coal-based electricity generation today. Storage of the CO2 is envisaged either in deep geological formations, or in the form of mineral carbonates. Deep ocean storage is not currently considered feasible due to the associated effect of ocean acidification. Geological formations are currently considered the most promising sequestration sites. The National Energy Technology Laboratary (NETL) reported that North America has enough storage capacity for more than 900 years worth of carbon dioxide at current production rates. A general problem is that long term predictions about submarine or underground storage security are very difficult and uncertain, and there is still the risk that CO2 might leak into the atmosphere.