1. Energy Harvesting Day 1: Energy Review
April 15, 2013 Paul Nickelsberg Orchid Technologies Engineering and Consulting, Inc.

2. Energy Harvesting Review
Energy harvesting is the process of capturing trace amounts of naturally occurring energy from various sources.
Accumulating the Energy
Storing the Energy
Applying the Energy for Useful Purpose

3. Measures of Energy – SI Units
SI System Fundamental Units
Unit of Length is the meter (m)
Unit of Mass is the kilogram (kg)
Unit of Time is the second (s)
Also called the MKS (meter/kilogram/second) System 3

4. Measures of Energy – SI Units Base Units
Physical Measure
Unit of Measure
Modern ‘Base’ Unit Definitions
Length
Meter
Distance light travels in 1/299,792,458 Seconds
Mass
Kilogram
Mass of International Kilogram
Time
Second
Duration of 9,192,631,770 periods caesium 133
Ampere
Electric Current
Force in conductors 1m apart
Kelvin
Temperature
Fraction 1/ temperature triple point water
Mole
Quantity of Matter
Elementary particles of kg carbon 12
Candela
Light Intensity
Raiant intensity of luminous source 4

5. Measures of Energy – SI Units Derived Units of Interest
Physical Measure
Unit of Measure
Modern ‘Derived’ Unit Definitions
Newton
Force / Weight
Newton (kg m/s²)
Joule
Energy / Work / Heat
Newton – meter (kg m²/s²)
Watt
Power
Joules per second (kg m²/s³)
Coulomb
Electric Charge
Second Amps (s A)
Volt
Electromotive Force
Watt per Amps (W / A)
Ohm
Electrical Resistance
Volts per Amps (V / A)
Farad
Electrical Capacitance
Charge per Volt (C / V)
Weber
Magnetic Flux
Volt Second (V s)
Henry
Electrical Inductance
Weber per Amp (Wb / A) 5

6. Measures of Energy – SI Units Scaling Prefixes
Name
Factor
hecto- (h)
10²
centi- (c)
10¯²
kilo- (k)
10³
mili- (m)
10¯³
mega- (M)
10⁶
micro- (µ)
10¯⁶
giga- (G)
10⁹
nano- (n)
10¯⁹
tera- (T)
10¹²
pico- (p)
10¯¹²
penta- (P)
10¹⁵
femto- (f)
10¯¹⁵
exa- (E)
10¹⁸
atto- (a)
10¯¹⁸
zetta- (Z)
10²¹
zepto- (z)
10¯²¹
yotta- (Y)
10²⁴
yotta- (y)
10¯²⁴ 6

7. Units of Measure – SI Units
Force
- Newton (kg m/s²)
Work / Energy
- Newton-meter (Joule) (kg m²/s²)
Power
- Joule per second (Watt) (kg m²/s³) 7

8. Units of Measure – SI Units Mechanical Force
F = ma
mass in kilograms
acceleration in meters/sec²
A 1kg apple (big apple) accelerates at m/s² hitting the head with nm of force. 8

9. Measures of Energy – SI Units Mechanical Work
‘Work’ is the amount of energy transferred to a system by the action of force acting along a finite distance
Car pulled down level street by three people each exerting 2100N of force directly on the back of the car for 125 meters before they got tired did: (2100N * 3) * 150m = 9.45 x 10⁵ Joules
Human heart moves a cylinder of blood in a 4cm diameter aorta. Force is 0.2N,
distance is m, per beat the heart does:
0.2N * m = Joules 9

10. Units of Measure – SI Units Mechanical Power
‘Power’ is the time-rate at which a certain amount of work is performed.
The energy to move the car 150m was 9.45 x 10⁵ Joules. If it took them two and a half minutes to move the car, the power expended was:
9.45 x 10⁵j / 150s = 630 Watts
630 / = 0.84 Hp
If the heart beats 72 times per minute and we average the energy per beat
to find the power in watts generated by the heart we find:
0.0111j * 72 = joules / minute
/ 60 = Watts (13mW) 10

11. Units of Measure – SI Units Other Interesting Units
Kilowatt-hour – measure of energy
- A measure of energy
- Thousands of Watts * Hours
- 3,600,000 joules = 1.0 kWh
Horsepower – measure of power
- 1Hp = 746 Watts 11

12. Units of Measure – SI Units Unit Conversions
To Convert From To
Multiply By
BTU (Energy)
Joule
1.05 x 10³
Calorie (Energy)
4.18 x 10⁰
Electronvolt (Energy)
1.60 x 10⁻¹⁹
Foot-pound
1.35 x 10⁰
Kilowatt Hour
3.60 x 10⁶
See The International System of Units (SI) catalogue of Measures for other very helpful conversion formulas. 12

13. Energy Harvesting Review
Energy harvesting is the process of capturing trace amounts of naturally occurring energy from various sources.
Energy is that which we pay in order to get things done.
Power is the rate at which we make payment of energy in order to get things done. 13

14. Energy Harvesting Review
Energy harvesting is the clever identification of potential sources of energy, and the collection, transformation and storage of that energy for application to a particular purpose.
Clever identification: Sun Light
Collection: Solar Cell
Transformation: Solar Cell
Storage: Battery
Purpose: Save Gas 14

15. Energy Harvesting Review
Energy harvesting is the clever identification of potential sources of energy, and the collection, transformation and storage of that energy for application to a particular purpose.
Specs: Wingspan 63.4m, Solar Cell Area: 200m², Weight 1,600 kg, Motors: 4 x 7.5kW (10Hp) Each, Cruise Speed 70 km/h 15

16. Energy Harvesting Review
Energy harvesting is the clever identification of potential sources of energy, and the collection, transformation and storage of that energy for application to a particular purpose.
F = ½ * r * S * C * V²
R = air pressure
S = Surface Area
C = Lift
V = Wind Speed
Energy = F * Distance
This is a momentum equation 16

17. Energy Harvesting Review
Energy harvesting is the clever identification of potential sources of energy, and the collection, transformation and storage of that energy for application to a particular purpose.
Jaeger-LeCoultre Atmos Clock
Temperature and pressure
variation winds main spring 17

18. Energy Harvesting Review
Energy harvesting is the clever identification of potential sources of energy, and the collection, transformation and storage of that energy for application to a particular purpose.
Self-winding watch mechanism
ETA 2824
Normal arm motion winds
the main spring 18

19. Energy Harvesting Sources
Photo Electrical – Light
Magnetic Inductive – Motion / Vibration
Radiated Energy – RF Sources
Piezoelectric – Vibration
Thermal – Heat
Chemical - Batteries 19

20. Energy Harvesting Sources
The World of Energy Sources
RF Energy
Vibration Energy
Thermal Energy
Photovolatic
Energy
Density 0.1 µW/cm²
Density 1 mW/cm²
Density 10 mW/cm²
Density 100 mW/cm² 20

21. Energy Harvesting Review
Step 1: Identify Energy Needs
Operate valve motor twice daily
Operate Ignition once daily
Step 2: Match Energy Source
Polycrystalline Solar Cell
Lithium Ion Battery
Step 3: Implement Device
Select Motor / Valves
Select Igniter
Select Control Microprocessor
Select Monitor Sensors
Step 4: Consider Failure Modes 21

22. Energy Harvesting Review
Come back tomorrow 22