As energy demands increase, a newer energy alternative are becoming more important to our society and also consumers want a safer and cleaner energy for our environment.
Capstone Micro Turbine generator is a new technology founded in 1988 is similar to jet engine and has a size of refrigerator, the first micro turbine was sold in 1998 after a research development and field application of advanced has turbine driven generator technology. In General we know the old traditional type of generator that uses pistons and oil to lubricate or coolant. However this type of Generator is way different. It has only one moving part called the shaft. Works on an air bearing technology connected to a digital power controller. Capstone Turbine operates on liquid fuels.
It can be used in different application which produce electricity and by installing an absorption chiller to the exhaust (waste) which we can use it for air condition and cool/hot water.
However the micro turbine provides input
mechanical energy, which is converted by the generator to electrical energy. The generator frequency is usually in the range of1.4-4 kHz. This frequency is converted to the supply
frequency of 50 Hz by a converter .The electrical energy
passes through a transformer, is delivered to the
distribution system and the local load .
Operation of Capstone Turbine
The capstone micro turbine generator uses the methane gas from anaerobic digester as fuel to produce electricity.
Capstone use expansion of high-pressure gas in the generator to produce electricity, Capstone Micro turbine is different. The fuel is mixed with air, compressed, combusted and expands using only one moving part supported by patented air bearing called the shaft and this shaft spins up to 50000-120,000 rpm (round per minute), and it doesn't require any lubricant or coolant that means no need for oil to change.
The Digital power electronics controls the turbine operation and all power conversion functions it used to convert high frequency power from the generator into useful 50 to 60 Hz in three phases out. 400-480V
Capstone operates on 5 different liquid fuels
- Natural Gas
-Biogas (landfill, wastewater treatment centers, anaerobic)
-Diesel
-Propane
-Kerosene
Capstone makes different sizes of Micro Turbines: 30kW, 65kW, and 200kW.
Classification of the Shaft
The shaft works on an air bearing technology the provides a lubrication solution. The air bearings in Capstone turbine provides longer engine life and requires no maintenance and reduces the footprint in the air.
What is the secret of this shaft!
The resisting force and the heat it creates energy loss and leads to material breakdown. Lubricants are used to reduce friction between bodies help transfer heat generated by their motion against one another. And the usage of oil cause many problems by friction. However this kind of technology solve all those problems and makes it oil free, and it has many advantages and beneficial to the environment.
Technical Background
Capstone Turbine contain of a turbine, compressor, generator and power electronics to deliver the power to the grid.
The MTG be divided into three primary sub-
systems:
Mechanical : including turbine, generator ,compressor
and recuperator.
Electrical: including main control software, inverter and
power firmware.
Fuel: including fuel delivery and combustion chamber
During engine operation, engine air is drawn into the
system and passes through the recuperator where temperature is increased by hot gases. The air flows into the
Combustor where it's mixed with fuel, lights up and burnt. This is used only during start up and then the flame is self supporting.
The combusted gas passes through the turbine converting into thermal energy of the hot
expanding gases to rotating mechanical energy of the turbine.
Recuperated, is a heat exchanger which
recover the heat from the exhaust gas to boost
the temperature of combustion and increase
the efficiency. Therefore To reduce the amount of fuel required by the turbine.
The design is digital to give it the flexibility of
adaptation to different engine types.
Power Conditioning System
Converts the unregulated, variable-frequency output of the generator
into a regulated waveform and manages the
interaction with any applied load both in stand-alone and
Utility connect modes.
Output voltage and frequency are software
adjustable between 380-480 V and 50-60 Hz, allowing the
system to be easily configured for operation.
Power Controller
The overall power conversion process is managed
by an advanced microprocessor-based control system.
Unique control algorithms and active filtering techniques.
Operating Modes
Grid connect
Allows micro turbine to be connected in parallel with an electric utility. When a utility grid disturbance happens, the protective relay functions integrated into the turbine will automatically shut down the system. The turbine can restart automatically to resume supplying electricity to connected loads once grid power returns to normal. In grid Connect mode, the microturbine is a current source only- the electric utility use for both voltage and frequency. The turbine can be used to provide base load power or shave peak power based on loads .
Stand Alone or Dual mode option
This option allows operation either with or without connection to an electric grid (Grid connect or Stand Alone operation) this Dual mode includes two large battery packs used start and transient electrical load management. The battery packs are lead-acid type and completely sealed. When operating Stand Alone option, the system can power connected loads at user voltage and frequency set points. It can power remote facilities such as construction sites, oil fields and other location where the electric utility grid is not available.
Stand Alone Application
This application is more complicated than Grid Connect because only the turbine is being relied upon for load power. Each turbine will try to maintain its pre-set voltage, regardless of the connected loads, if the load is above the capability of the engine to provide continuous power, the batteries in the turbine will supply the shortfall in an attempty to keep the system running. If this overload condition continues, the batteries will die and the system will shut down.
Capstone Performance Test
Endurance: is a measurement of Micro Turbine.
Daily operating: fuel flow, air pressure, operating
temperature and humidity, energy [Kwh], and Pressure.
Transient Response: Micro Turbine should be able to respond
Immediately to load changes.
Harmonic Distortion: the power output will be measured for
Total harmonic distortion as well as power factor of the total loaded unit to identify whether the Micro turbine achieves rated output when connected to the utility grid.
Noise Measurement: Measurement of Noise of the motor meter during operation
Emissions Level Monitoring: to check whether NOx and CO
levels are within the levels with a small tolerance .
Combined cooling, heating & power CCHP
It provides both electricity and heat. The electricity can be used for loads near the site, or can be fed into the electric grid. The electric generation equipment in the CCHP system is usually driven by the combustion of fuel. Part of the combustion heat can't be used to generate electricity; the combined heat and power system recovers this heat into cooling using absorption chiller refrigeration equipment for heating Jacuzzis and produce domestic hot water for consumers
Normally the production of electricity is not efficient, due to heat rejected to the environment. By making use of this waste heat, the overall system efficiency is improved and more usefully energy is produced per unit of fuel. This can result in reduces total greenhouse gas and other pollution emission like NOx .
The benefits of capstone micro Turbine
Uses waste gas to produce heat and electricity.
Uses air bearing means no lubricating oil or coolant.
Low emissions ( no pollution, friendly for the environment)
One moving part : low maintenance
Remote monitoring (small computer checking)
Small, modular design allows for easy , low cost installation and easy transportation
Reliable: tens of millions of run hours
Works 24/7)
Where Capstone micro turbine is used
Office buildings & large Retailers
Providing power security and economic benefits for large retailers
Hospitals
Where is more fuel efficient and environmentally beneficial than boiler heating significantly cutting monthly bills
Hotels & Universities
The exhaust heat from capstone micro turbine provide hot water or drive an absorption chiller for air-conditioning and heating.
Digesters ( waste from animals)
Captured methane has from digesters as fuels for capstone while reducing green house has emissions.
Landfills/Garbage Processing
Ability to run on various gases from Garbage gases.
Waste water treatment plants
Capstone use methane gas created by digesters to generate electricity & heat.
Data center & telecom ( provide main power for data centers and telecom sites
Facts
Capstone turbines provide 35% of building's day to day electricity needs and up to 80% of heating needs
Turbines cut the CO2 footprint in half or better.
During "grid event" the turbines reconfigure to provide back up power to designated protected load.
Capstone is a leader in developing Micro turbine technology and has nearly 100 patents worldwide
The highly reduced emission of pollutants resulted in annual emissions reductions equivalent planting 49,932 acres of forest or removing the emissions of 33,288 cars.
Conclusion
This modern technology of power generation has many important aspects in our lives, as we are pay attention and care for our environment friendly power generations.
Micro Turbine generator is becoming popular around the world because of its eco friendly nature along with power delivery with high efficiency.
As another solution of hot water heat from the waste heat of the Micro Turbine as this solutions used for absorption chiller (air-condition) and backup power functions resulting in saving money and increase in power reliability, with clean emissions, as well as reducing greenhouse gas productions.
The development of Micro turbine technology is also applied for transportation system applications.
