Post on 11-Feb-2017
Discussion of what is energyEnergy not just oil. gas or solar – not just a commodity Basic phyisical parameter/characteristic Deep connections between energy order and the development of intelligence
Physics definitionsWork = making a change in the universeEnergy = Ability to do workPower = rate at which work is done - speedometer/odometerr analogyTypes of energyUnits definitions for the aboveConverting from one unit to another (like distance measurments)No energy is “lost” – wasted energy , like a weed, is energy we have no use forMention energy quality, more detailed lecture next day
A few sample calculationsDemos? Heat things to the same temperature and have people touch them – specific heat?Solar hot waterIntroduce concept of specific energy
Lecture 1Concept of Energy
E-101 - Energy and Sustainability Professor Lonnie Gamble
Sustainable Living Department Maharishi University of Management
This presentation was prepared on solar powered computers
Work, Energy, Power
Work: Something that makes a change in the Universe
Energy: The ability to do work = Joules
Power: The rate at which the work is done = Joules per second (watt)
The Units of Energy and PowerEnergy:
JouleBTU - 1 lb water up one degree FCalorie - 1 kg of water up one degree CWatt-hour = 3600 joules Kilowatt-hour = 1000 watt hours
Power:Watts = joules/secondKilowatt = 1000 wattsBTU/hourHorsepower - 746 watts
Energy Units:British Thermal Unit (BTU)
BTU is commonly used as for measuring heat energy. A BTU is roughly amount of
energy released in striking a match
Energy Units: Watt-hours
Watt hours are typically used to measure electrical energy.
A watt-hour is a pretty small unit - it takes 50 of them to make your toast - a kilowatt-hour is 1000 watt-hours.
A typical utility-connected family uses about 1000 kilowatt-hours per month of electrical energy.
1 watt-hour=3.41 btu1 kilowatt-hour = 3410 btu
Main Point # 1Energy is the ability to do work, and is absorbed or released when change happens. Some examples: change in pressure, change in temperature, change in voltage, change in chemical concentration change in elevation in a gravitational field.Power is the rate that energy is being produced or consumed In order to do, one must think, in order think, one must be. Therefore, the source of action and change is ultimately being.
Power Units:Watt =Joule/second
A watt is a pretty small unit - it takes 1000 of them to run your toaster.
A kilowatt is 1000 watts.
1 Kilowatt (kW) = 1000 Watts = 1000 joules/sec
Main Point # 2
Power is a measure of energy flow, the rate at which energy is produced or consumed.
Consciousness flows effortlessly from being to form the universe.
Main Point # 3There are two main forms of energy:
Kinetic – energy related to movement example: flowing water, windPotential - energy related to position or state example: ball at the top of a hill
Being is pure potentiality. In contrast, the manifest universe is eternally in motion.
Energy is neither created nor destroyed – it eternally changes from one form to another. Curving back on myself I create again and againThe unchanging unified field is neither created nor destroyed but gives rise to the cycles of creation, maintenance, and destruction at the surface of life.
There is no “wasted”energy – energy doesn’t disappear
But energy can loose it’s usefulnessCar example
Example - Some Energy Transformation Calculations
Google calculator and google units converter – Use the form “10.5 cm in inches”
Solar hot water system – Krystofiak
PV system design
Energy Center web site PV watts
Heat Energy
Heat is energy that comes from molecular motion.
Heat is the form of energy that flows from warm to cold objects.
Heat flows spontaneously from hot to cold. It takes energy to move heat from cold to hot.
Other forms of energy can be converted to heat at 100% efficiency
Temperature
Temperature is what increases when energy flows into something and decreases when energy flows out of something
Ex: What involves more energy -Heating water from 112 to 212 degrees F- Lowering the temperature of a
swimming pool by 1 degree F
Heat Transfer
Conduction - heat flow by direct contact between objects
Convection - heat flow by fluid motion
Radiation - heat flow by direct transfer through space
Conduction(slowed by insulation)
Convection(stop convective
loops)
Radiation (Stopped by shiny surfaces)
Heat Loss Through Walls
Heat Loss in BTU/HR= A* (Tin-Tout)/RTin-Tout= delta T
Outside Temp = 20 deg F
Inside Temp = 70 deg F
R value = 20
Heat Storage, Specific HeatSpecific Heat: energy required to raise 1 lb
of material 1 degree FWater = 1 btu/lb per deg FStone, concrete= .23 btu/lb per deg F Sand = .19Pine = .6Gypsum = .26Copper = .09Earth Block = .25 600 tons of earth block in the SL center
What involves more heat flow:
Heating 10 lbs of water from 55 degrees to the boiling point?
OR
Lowering a 70 degree swimming pool temp to 69 degrees?
Heat Flow Time Lag
Stone, Concrete: 1 inch per hour
Desert buildings heating example(Sunspace)
Passive cooling example – masonry building
Heat and Phase ChangesLatent Heat
Water as ice at 32 degrees to water as liquid at 32 degrees requires 143 btu/lb
Liquid water at 32 degrees to liquid water at 212 requires 180 btu/lb
Water as liquid at 212 degrees to water as gas at 212 degrees requires 1040 btu/lb
Main Point #5
Heat is a special form of energy related to molecular motion that flows from warm to cold objects. Temperature drops when heat flows out of an object, temperature rises when heat flows in to an object. During meditation, the mind naturally flows from greater to lesser activity to the field of least action, being
• SAI will bring increasingly cost-competitive systems to market between now and 2015, with benefits accruing from the early SAI years.
SAI Cost Reductions
Most frequently identified non-technical barriers to solar energy implementation, listed in order of frequency.
High cost (addressed by all SAI activities, including R&D effort)Lack of trained technical personnel, reliable installers, and maintenance servicesLack of communication, information dissemination, and consumer awarenessInadequate financing optionsLack of appropriate, consistent interconnection standards
Inadequate government incentivesLack of equitable and effective net-metering guidelinesInadequate codes and standardsLiability issues / insurance requirementsPoor public perception of solar system aesthetics
Non-Technical Barriersto Solar Commercialization
“Someday, after we have mastered the winds, the waves, the tide and gravity, we shall harness for God the energies of love. Then for the second time in the history of the world, man will have discovered fire.” - Teilhard de Chardin
Specific Heat Demo• Demo 008• Specific Heat of Lead• This is not for the faint of heart or for those who religiously adhere to OSHA guidelines. Lead has a very low specific heat; this demonstration uses this fact in a dramatic way when
the demonstrator dumps hot lead pellets (100°C) onto his or her open hand.• MATERIALS• 25 g of lead shot
One large test tube (8 in)Ringstand and clampHot plate500 mL beaker with 300 mL of distilled water.Paper towels for cleanupTongs for holding hot test tubeInsulated gloves to handle the hot hotplate and water
• PREPARATION• Place the beaker containing the water on the hot plate and heat to boiling. Place the lead shot in the test tube, clamp the tube in place so that the lead-containing portion dips
well into the hot water.• PRESENTATION• This demonstration should follow a discussion of specific heat, the calculation of amounts of heat required to bring about given temperature changes, and a discussion of the
magnitudes of the specific heat of various substances. The point to make is that water has an exceptionally high specific heat and that lead metal has a very low specific heat. This demonstration exploits these facts.
• Compute the temperature change when 25 g of lead at 100°C as added to 25 g of water at 25°; it should be only 2-3 degrees. Ask the class if they believe the result of these calculations; more specifically, ask if they would be willing to have 25 g of lead at 100°C poured into their open hand (which is mostly water).
• With as much drama and flourish as you wish, remove the test tube from the boiling water and pour the hot lead shot into your hand. It will feel quite warm, but not painful. Ask whether anybody would want to repeat this with 25 g of boiling water. Be sure to demand an explanation for the expected negative response.
• DISCUSSION• Since the specific heats of water and lead are 4.184 J/g°C and 0.16 J/g°C, respectively, the quantity of heat transfered from the lead to its surroundings will be only around 4% of
the amount released by an equal weight of water.• HAZARDS• This works very well with 25 g of lead. Don't try to scale up the demonstration! There is no disposal to speak of. The lead can be recycled for the next class, and the water can be
poured down the drain after it cools a bit.• REFERENCES• None for this demonstration that I know of...maybe a book on magic tricks.