Learning Objectives
Understand and be able to explain the following:
How energy flows from the sun and through all life on earth
How photosynthesis uses energy from sunlight to make food and other forms of energy
Biofuels and Fossil Fuels
Chains of carbon and hydrogen atoms•Energy is stored in the bonds
Animal fats and oils
Algae is another viable sources of energy
How do fuels provide energy?
The activities of living organisms are fueled by breaking chemical bonds and harnessing the released energy.
Energy Conversions
All life depends on capturing energy from the sun and converting it into a form that living organisms can use.
Two key processes•Photosynthesis•Cellular respiration
Take-home message
The sun is the source of the energy that powers all living organisms and other “machines.”
The energy from sunlight is stored in the chemical bonds of molecules.
Take – home message
• Kinetic energy is the energy of moving objects.
. Potential energy is stored energy or the capacity to do work that results from the position or location of an object.
• Inertia energy is the property of an object to resist changes in its motion.
Potential Energy
A capacity to do work that results from the location or position of an object
Concentration gradients and potential energy
Inertia Energy
If a body is at rest, it tends to remain at rest. If a body is moving
at constant velocity, it tends to keep moving at that velocity.
Energy Conversions Only ~1% of the energy released by the sun
that earth receives is captured and converted by plants.
•Converted into chemical bond energy What happens to the other 99%?
First Law of Thermodynamics
Energy can never be created or destroyed.
It can only change from one form to another.
Showing the heat in the hydraulic cylinders and where there bypassing
*>74.4°C
*<25.3°C
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
70.0
Energy Tax! Every time energy is converted from one form to
another the conversion isn’t perfectly efficient. Some of the energy is always converted to the least
usable form of kinetic energy: heat.
Second Law of Thermodynamics
Every conversion of energy includes the transformation of some energy into heat.
Heat is almost completely useless to living organisms
Take-home message
Energy is neither created nor destroyed but can change forms.
Each conversion of energy is inefficient and some of the usable energy is converted to less useful heat energy.
Light energy travels in waves: plant pigments absorb specific wavelengths
Light Energy
A type of kinetic energy
Made up of little energy packets called photons
Light Energy
Different photons carry different amounts of energy, carried as waves.
Length of the wave = amount of energy the photon contains.
Electromagnetic Spectrum Range of
energy that is organized into waves of different lengths.
Shorter the wavelength, higher the energy.
Take-home message
Photosynthesis is powered by light energy, a type of kinetic energy made up from energy packets called photons.
Photosynthesis in detail: the energy of sunlight is captured as chemical energy.
FOLLOW THE ELECTRONS!
Take-home message
There are two parts of photosynthesis.
The first is the “photo” part, in which light energy is transformed into chemical energy while splitting water molecules and producing oxygen.
Take-home message
Living organisms extract energy through a process called cellular respiration in which the high-energy bonds of sugar and other energy-rich molecules are broken, releasing the energy that went into creating them.
Take-home message
Oxygen deficiency limits the breakdown of fuel because the electron transport chain requires oxygen as the final acceptor of the electrons generated during the rebuilding cycle.
Liquids transmit applied pressure in all directions, and act with equal
force at right angels to all surfaces
Energy put into a hydraulic system in the form of flow under pressure
will result in either work or heat
Hydraulics is the means of power transmission.
Energy Formulas
1 Kw = 1.3 hp
1 hp = 550 ft. lbs/s
Hydraulic hp = Gpm x psi
1714
Torque (in. lbs) = psi x disp. (in3/rev.)
6.28
Torque (in. lbs) = hp x 63025
rpm
Hp = Torque (ft.lbs) x rpm
5252
Btu (per hour) = psi x gpm x 1.5
Work (in:lbs) = force (lbs)x distance (in)
Power = Force x Distance
Time
Important: As all systems are less then 10% efficient and efficiency factor must be added to the calculated input horsepower.
Example: Input hp = 10 gpm x 1500 psi = 8.75 hp = 10hp
1714 (constant) 0.85 (efficiency)
Rule of thumb: 1 gpm @ 1500 psi = 1.0 input hp
Energy Formulas
Flow Formula1 gal= 231 in/3
Cylinder Volume Displaced (in/3) = stroke x Effective Area
Cylinder Speed (ft/min)= gpm x 19.25
Effective area (in/3)
Gpm (theoretical) = Pump rpm x in 3/rev
231
Volume required (gpm) =
Volume Displaced x 60
Tlme(s) x 231
Volume Required (Hyd. Motor) =
rpm x disp. (in/3)
231
Pressure Formula1 Bar = 14.5 psi.
Psi = lbs = Pounds per square inch
in/2__________________________
Force (lbs) = Pressure (psi) x area (in/3)
Pressure (psi) = Force (lb)
Area (in/2)
Area (in/2) = Force (lb)
Presuure (psi)_____________
Area = d/2 x 0.7854
There are Two Types of Hydraulics
• The hydrostatic drive is a fluid drive which uses fluid under pressure to transmit engine power to the drive wheels of the machine.
• Hydrostatics is the use of fluids at high pressure but relatively low speeds.
• Hydrodynamics is the use of fluids at high speeds that impact another member to supply power. (Kinetic energy)
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