Chapter 1: Energy

From the sun to you in two easy steps

Lectures by Mark Manteuffel, St.

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

What are biofuels?

Cars that run on french fry oil? Organisms and machines need energy to work.

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.

Energy has three forms.

Kinetic , PotentialAnd

Inertia

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.

What is energy?

The capacity to do work

Work•Moving matter against an opposing

force

Kinetic Energy The energy of moving objects

•Heat energy•Light energy

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.

Inertia Energy

Chemical Energy

As energy is captured and converted, the amount of energy available to do work decreases.

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%?

Thermodynamics

The study of the transformation of energy from one type to another

First Law of Thermodynamics

Energy can never be created or destroyed.

It can only change from one form to another.

ThermographShowing heat on connections of a voltage

regulator

After repair the temperature was lowered by 77.0F

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!

Electrons That Leave the Photosystem Are Replenished

Where does oxygen come from?

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.

by-products of cellular metabolism in the absence of oxygen.

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.

Fluid Power and Energy

Hydraulics – How it works

Liquids have no shape of their own

Liquids are practically incompressible

Liquids transmit applied pressure in all directions, and act with equal

force at right angels to all surfaces

Liquid under pressure follow the path of least resistance

Pressure can be created only by a resistance to flow

Flow across an orifice results in a pressure drop

Hydraulic systems can provide a great increases in work force

Energy put into a hydraulic system in the form of flow under pressure

will result in either work or heat

Pressure, Area, Displacement and Flow

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

Force is pressure Multiplied by area

Basic Hydraulic Systems

Reservoir and Check valves

Open Center System

Open Center System at Work

Close Center Systems

Closed Center Systems at Work

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)

Series Connections

Series Valves Activated

Series-Parallel Connection

Flow Dividers

Variable Displacement Pumps

Closed Center, with Accumulators

Priority Valves

Pressure Compensated Systems

Flow Compensated

Hydrostatic, Closed Looped Systems

Steering Systems With Drag Link

Poppet Type Hydrostatic Steering

Metering Pump Steering

Metering Valve

Hydraulic Brakes

Hydraulic Facts