Does This Energy Storage System Have Potential? ENGINEERING.com

Does This Energy Storage System Have Potential? ENGINEERING.com

t’s not a new concept: When a wind turbine or solar array generates more energy than you’re using, the excess energy can be stored by pumping water into an elevated holding tank, converting kinetic energy into potential energy. When energy is needed, the water flows down and spins a turbine that generates electricity.

Engineers at MIT are proposing a similar system for off-shore wind turbines, but instead of an elevated holding tank, the water would be stored in a 25 meter concrete spherical tank that also anchors the floating turbine to the ocean floor. The sphere is placed at a depth of 400 meters. Excess electrical energy pumps water out of the tank and into the ocean, and when energy is needed the water flows back into the sphere and drives a hydroelectric generator. 

ANALYSIS OF FUEL CELL TECHNOLOGY FOR SUSTAINABLE POWER GENERATION

ABSTRACT: In today’s developing world the need for energy is growing exponentially on the other hand it’s environmental effects are attracting our attention. Researchers believe that increasing levels of greenhouse gas emissions are changing the climate around the globe. Fulfilling the growing energy needs and solving environmental problems at present would be a big investment for our future. Although renewable energy sources can provide superior environmental performance but for long term, incremental investments in a new domestic energy source infrastructure is necessary for the next century. Trend in energy use from the past indicates a slow transition from fuels with high carbon content, starting from wood to fuels with more hydrogen. Hydrogen is the most suitable fuel for fuel cells because of excellent electrochemical reactivity as well as zero emission characteristics. Fuel cells were used in the past in the space program to provide electricity and drinking water for the astronauts.  In future, the combination of high efficiency fuel cells and fuels from renewable energy sources would nearly eliminate greenhouse gas emissions. The early transition to lower carbon based fuels will begin to create cleaner air and will satisfy the growing energy needs. In this paper analysis of developing Fuel cell Technology is carried out and is presented for different applications.

Keywords: Clean fuels, Fuel Cell, Power Generation, Renewable Energy.

INTRODUCTION

World is witnessing a worsening global warming situation as generation is continuously being increased throughout the world using fossil fuels. Higher energy generation through fossil fuel imparts environmental degradation and is now a matter of concern globally. The balance of evidence suggests that there is a discernible human influence on global climate. This calls for optimization of generation of energy through well-known sources and also for conservation in the utilization front as short term measure. The long-term measure really calls for search of new sources, preferably renewable energy for commercial exploitation.  In comparison to other renewable sources fuel cells have a distinct advantage that it can produce continuous power as long as they are supplied with a constant supply of hydrogen (Appleby and Foulkes, 1989; Fuel Cell Handbook, 2000; USDOE, 1998). This ability to deliver uninterruptible electrical energy makes fuel cells well suited for various applications such as for security application. However, the use of fuel cell is limited due to high cost of manufacturing of it’s components. Now due to better technology and bulk requirements fuel cells are finally coming into the market (Wayne, 2001).

In principle, a fuel cell operates like a battery but it does not run out or require recharging. It will produce energy in the form of electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes sandwiched around an electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricity, water and heat. Hydrogen fuel is fed into the anode of the fuel cell. Air (or oxygen) enters the fuel cell through the cathode. Encouraged by the catalyst hydrogen atom splits into proton and electron, which takes different paths towards the cathode. The proton passes through the electrolyte. The electrons create a separate current that can be utilized before they return to the cathode, to be reunited with the hydrogen and oxygen in a molecule of water. A fuel cell system which includes a “fuel reformer” can utilize the hydrogen from any hydrocarbon fuel like from natural gas to methanol, and even gasoline. Since the fuel cell relies on chemistry and not on combustion, emissions from this type of a system would still be much smaller than emissions from the cleanest fuel combustion processes available (Gerlach , 2002; Twidel,1986).

FUEL CELLS

A fuel cell is an electrochemical device used to generate electricity. The fuel cell stack is just one component of the overall fuel cell system. The system has three basic sub-systems: the fuel processor, the fuel cell stack, and the power conditioner. “Balance of plant” components include pumps, compressors, heat exchangers, motors, controllers and batteries. In many cases, standard “off-the-shelf” components are just not suitable for use in a fuel cell system, and specialized components must be designed and manufactured. The fuel cell stack utilizes a hydrogen rich gas stream, and there are several approaches to supplying the hydrogen on-board the vehicle. Hydrogen can be stored as a cryogenic liquid at -423ºF, held as a gas in pressurized tanks, or contained with metal or chemical hydrides (which employ chemical reactions to store and release hydrogen). Or, the hydrogen can be extracted or “reformed” from liquid fuels such as gasoline, synthetic hydrocarbon fuels, methanol and ethanol, that act as hydrogen carriers. Fuel cells are direct current (DC) power generators. In some fuel cell vehicle applications the fuel cell’s DC power is converted to alternating current (AC) to run AC induction motors, requiring the use of AC motor controllers (Bose, 2000). In other cases, DC motors are used, governed by DC motor control systems. Much of the of work and resources committed to the development of battery electric vehicle drive trains in recent decades is being applied to fuel cell vehicle applications.

Fuel cells have a distinct advantage over other clean generators such as wind turbines and Photovoltaic that it can produce continuous power as long as it is supplied with a constant supply of hydrogen (Tyagi, 2005; Ellis, 2001). This ability to produce continuous power makes fuel cells well suited for supporting critical loads for security applications. The power output of fuel cells is also of high quality in that it is clean and provides computer grade power free from voltage disturbances such as sags, spikes or transients. Distributed power is a new approach utility companies are beginning to implement by locating small, energy-saving power generators closer to where the need is. Because fuel cells are modular in design and highly efficient, these small units can be placed on-site (Tyagi, 2005). Installation is less of a financial risk for utility planners and modules can be added as demand increases. Utility systems are currently being designed to use regenerative fuel cell technology and renewable sources of electricity. 

MATLAB output for node deployment and clustering of wireless network for optimum allocation

MATLAB program for sizing and siting of Distributed Generators for simple % % Radial power system

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Sample bus complex powers (P & Q) in MW %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

P1 = 7.5; P2 = 6; P3 = 4; P4 = 2; P5 = 1.5; P6 = 1; % IEEE source simulation purpose
Q1 = 6.61; Q2 = 3; Q3 = 2.3; Q4 = 0.45; Q5 = 0.25; Q6 = 0.5;

% Complex power at each node

C1 = P1+i*Q1; C2 = P2+i*Q2; C3 = P3+i*Q3; C4 = P4+i*Q4; C5 = P5+i*Q5;
C6 = P6+i*Q6;

%%%%%%%%%%%%%%%%%%%%%%%%
% Bus voltages in Volts %
%%%%%%%%%%%%%%%%%%%%%%%%

V1 = 480; V2 = 480*(0.6996-0.0923i); V3= 480*(0.1624-0.0915i); V4 = 480*(0.0051-0.0152i); V5 = 480*(0.0735+0.0425i); V6 = 480*(0.1172-0.1123i); % Distribution network is assumed to be local

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Branch Resistance or Tie bus resistance in Ohm %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

R1 = 05; R2 = 0.1; R3 = 0.15; R4 = 0.1; R5 = 0.1; R6 =0.15;

Res = [R2, R3, R4, R5, R6];

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Equivelent Current Injection %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I1 = (P1 + j*Q1)'/V1;
I2 = (P2 + j*Q2)'/V2;
I3 = (P3 + j*Q3)'/V3;
I4 = (P4 + j*Q4)'/V4;
I5 = (P5 + j*Q5)'/V5;
I6 = (P6 + j*Q6)'/V6;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Current Injection Matrix %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I = [I2; I3; I4; I5; I6];

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Bus injection to branch current (BIBC) Matrix %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

R = [1 1 1 1 1; 0 1 1 1 1; 0 0 1 1 0; 0 0 0 1 0; 0 0 0 0 1];

% Bus Relation Matrix

B = R * I;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Power Loss in the system %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%

PLOSS = Res'.* real(B);

bus = 2:1:6;

bar(bus,PLOSS,0.5,'g')

title('\bf TotalPower loss in each bus')

xlabel('Bus Number')

ylabel('Power loss')

Magnetic circuits Assignment: course Basic Electrical Engineering

Assignment # 1

Basic electrical engineering

Q1. Define the following terms as applied to a magnetic circuit:

Permeability, Magneto-Motive Force (MMF), Reluctance, Permeance, Reluctivity

Q2. Give analogy between electric & magnetic circuits.

Q3. Explain briefly the following two types of losses which occurs in magnetic materials: hysteresis losses, eddy current losses

Q4. What do you understand by electromagnetic induction?

Q5. Explain briefly faradays first & second laws of electromagnetic induction.

Q6. State and explain Flemings right hand rule.

Q7. What is lenz’s law?

Q8. What is the difference between the dynamically and statically induced emf?

Q9. A three phase load consists of three similar inductive coils, each of 50 Ω and inductance 0.3 h. the supply is 415 v, 50 hz. Determine line current, power factor, total power when load is star connected and delta connected.

Matlab code for famous Mexican hat

code


% program to plot Maxican hat

[x,y] = meshgrid(-8:0.5:8);
r = sqrt(x.^2+y.^2)+eps;
z = sin(r)./r;
surfc(z), shading flat
axis off

Instrumentation and Measurement Objection Question book bank

  

(1) Instrument is a device for determining

(a) the magnitude of a quantity

(b) the physics of a variable

(c) either of the above

(d) both (a) and (b)

(2) Electronic instruments are preferred because they have

(a) no indicating part

(b) low resistance in parallel circuit

(c) very fast response

(d) high resistance in series circuit

(e) no passive elements.

(3) A DC wattmeter essentially consist of

(a) two ammeters

(b) two voltmeters

(c) a voltmeter and an ammeter

(d) a current and potential transformer

(4) Decibel is a unit of

(a) power

(b) impedance

(c) frequency

(d) power ratio

(5) A dc voltmeter may be used directly to measure

(a) frequency

(b) polarity

(c) power factor

(d)power

(6) An accurate voltmeter must have an internal impedance of

(a) very low value

(b) low value

(c) medium value

(d) very high value

(7) The insulation resistance of a transformer winding can be easily measured with

(a) Wheatstone bridge

(b) megger

(c) Kelvin bridge

(d) voltmeter

(8) A 100 V voltmeter has full-scale accuracy of 5%. At its reading of 50 V it will give an error of

(a) 10%

(b) 5%

(c) 2.5%

(d) 1.25%

(9) You are required to check the p. f. of an electric load. No p.f. meter is available. You would use:

(a) a wattmeter

(b) a ammeter, a voltmeter and a wattmeter

(c) a voltmeter and a ammeter

(d) a kWh meter

(10) The resistance of a field coil may be correctly measured by using

(a) a voltmeter and an ammeter

(b) Schering bridge

(c) a Kelvin double bridge

(d) a Maxwell bridge

(11) An analog instrument has output

(a) Pulsating in nature

(b) Sinusoidal in nature

(c) Which is continuous function of time and bears a constant relation to its input

(d) Independent of the input quantity

(12) Basic charge measuring instrument is

(a) Duddel's oscillograph

(b) Cathode ray oscillograph

(c) Vibration Galvanometer

(d) Bailastic Galvanometer

(e) Battery Charging equipment

(13) A.C. voltage can be measured (using a d.c. instrument) as a value obtained

(a) by subtracting the d.c. reading from it's a.c. reading.

(b) Using the output function of the multimeter

(c) By using a suitable inductor in series with it

(d) By using a parallel capacitor with it

(e) None of the above

(14) A moving coil permanent magnet ammeter can be used to measure

(a) D. C. current only

(b) A. C. current only

(c) A. C. and D. C. currents

(d) voltage by incorporating a shunt resistance

(e) none of these

(15) Select the wrong statement

(a) the internal resistance of the voltmeter must be high

(b) the internal resistance of ammeter must be low

(c) the poor overload capacity is the main disadvantage of hot wires instrument

(d) the check continuity with multimeter, the highest range should be used.

(e) In moving iron voltmeter, frequency compensation is achieved by connecting a capacitor across its fixed coil.

(16) Which of the following instrument is suitable for measuring both a.c. and d.c.

quantities.

(a) permanent magnet moving coil ammeter.

(b) Induction type ammeter.

(c) Quadrant electrometer.

(d) Moving iron repulsion type ammeter.

(e) Moving iron attraction type voltmeter.

(17) Swamping resistance is used in moving coil instruments to reduce error due to

(a) thermal EMF

(b) temperature

(c) power taken by the instrument

(d) galvanometer sensitivity.

(18) A power factor meter is based on the principle of

(a) electrostatic instrument

(b) Electrodynamometer instrument

(c) Electro thermo type instrument

(d) Rectifier type instrument.

(19) A potentiometer recorder is used for

(a) AC singles

(b) DC signals

(c) both (a) and (b)

(d) time varying signals

(e) none of these.

(20) Transformers used in conjunction with measuring instruments for measuring purposes are called

(a) Measuring transformers

(b) transformer meters

(c) power transformers

(d) instrument transformers

(e) pulse transformers.

(21) Leakage flux in an electrical machine is measure by

(a) Ballistic galvanometer

(b) Flux meter

(c) Either (a) or (b)

(d) Vibration galvanometer

(e) CRO

(22) A C.R.O. is used to indicate

(a) supply waveform

(b) magnitude of the applied voltage

(c) B.H. loop

(d) all of these

(e) Magnitude of the current flowing in it.

(23) An oscillator is a

(a) an amplifier having feedback network

(b) a high gain amplifier

(c) a wide band amplifier

(d) a untuned amplifier

(e) None of these

(24) Distortion can be measured by

(a) Wave meter

(b) Digital filters

(c) Wein bridge circuit

(d) Bridge T filter circuit

(25) Series connected Q- meter is preferable for measurement of components having

(a) high impedance

(b) low impedance

(c) both (a) and (b)

(d) high frequency

(e) low capacitance

(26) A potentiometer is

(a) an active transducer

(b) a passive transducer

(c) a secondary transducer

(d) a digital transducer

(e) a current sensing transducer

(27) The basic components of a digital voltmeter are:

(a) A/D converter and a counter

(b) A/D converted and a rectifier

(c) D/A converter and a counter

(d) Ramp generator and counter

(e) Comparator

(28) Which of the following electrical equipment cannot convert ac into dc

(a) diode

(b) converter

(c) transformer

(d) mercury arc rectifier

(29) Voltage measurement are often taken by using either a voltmeter or

(a) an ammeter

(b) an ohmmeter

(c) an oscillator

(d) a watt-meter

(30)The electric device which blocks DC but allows AC is called:

(a) capacitance

(b) inductor

(c) an oscilloscope

(d) a watt-meter

(31 ) The range of an ammeter can be extended by using a

(a) shunt in series

(b) shunt in parallel

(c) multiplier in series

(d) multiplier in parallel

(32)A device that changes one form of energy to another is called

(a) rheostat

(b) oscillator

(c) transducer

(d) varicap

(33) Aquadag is used in CRO to collect

(a) primary electron

(b) secondary electron

(c) both primary and secondary

(d) none of above

(34) A vertical amplifier for CRO can be designed for

(a) only a high gain

(b) only a broad bandwidth

(c) a constant gain time bandwidth product

(d)all of the above

(35) One of the following is active transducer

(a) Strain gauge

(b) Selsyn

(c) Photovoltic cell

(d) Photo emissive cell

(36) The dynamic characteristics of capacitive transducer are similar to those of

(a) low pass filter

(b) high pass filter

(c) band pass filter

(d) band stop filter

(37) Thermocouples are

(a) passive transducers

(b) active transducers

(c) both active and passive transducers

(d) output transducers

(38) The size of air cored transducers as compare to iron core counter part are

(a) bigger

(b) smaller

(c) same

(39) From the point of view of safety, the resistance of earthing electrode should be:

(a) low

(b) high

(c) medium

(d) the value of resistance of electrode does not effect the safety

(40) In CRT the focusing anode is located

(a) between pre accelerating and accelerating anodes

(b) after accelerating anodes

(c) before pre accelerating anodes

(d) none of above

(41) Which transducer converts heat energy into electrical energy

(a) I. V. D. T.

(b) thermocouple

(c) photoconductor

(d) none of the above

(42) Which of photoelectric transducer is used for production of electric energy by converting solar energy

(a) photo emission cell

(b) photo diode

(c) photo transistor

(d) both (b) and (c)

(43) Which of the following instruments consumes maximum power during measurement?

(a) induction instruments

(b) hot wire instruments

(c) thermocouple instruments

(d) electrodynamometer instruments

(44) Which of the following meters has the best accurancy

(a) moving iron meter

(b) moving coil meter

(c) rectifier type meter

(d) thermocouple meter

(45) The function of the safety resistor in ohm meter is to

(a) limit the current in the coil

(b) increase the voltage drop across the coil

(c) increase the current in the coil

(d) protect the battery

(46) Which of the following instruments is free from hysteresis and eddy current losses?

(a) M.l. instrument

(b) electrostatic instrument

(c) electrodynamometer type instrument

(d)all of these

(47) The dielectric loss of a capacitance can be measured by

(a) Wien bridge

(b) Owen bridge

(c) Schering bridge

(d) Maxwell bridge

(48) Reed frequency meter is essentially a

(a) recording system

(b) deflection measuring system

(c) vibration measuring system

(d) oscillatory measuring system

(49) In measurements made using a Q meter, high impedance elements should preferably be connected in

(a) star

(b) delta

(c) series

(d) parallel

(50) A digital voltmeter measures

(a) peak value

(b) peak-to-peak value

(c) rms value

(d) average value